Merge pull request #352 from telemt/bump

Update Cargo.toml

.github/workflows/release.yml

@@ -3,11 +3,12 @@ name: Release
 on:
   push:
     tags:
-      - '[0-9]+.[0-9]+.[0-9]+'  # Matches tags like 3.0.0, 3.1.2, etc.
-  workflow_dispatch:  # Manual trigger from GitHub Actions UI
+      - '[0-9]+.[0-9]+.[0-9]+'
+  workflow_dispatch:
 
 permissions:
   contents: read
+  packages: write
 
 env:
   CARGO_TERM_COLOR: always
@@ -37,11 +38,9 @@ jobs:
             asset_name: telemt-aarch64-linux-musl
 
     steps:
-      - name: Checkout repository
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@v4
 
-      - name: Install stable Rust toolchain
-        uses: dtolnay/rust-toolchain@888c2e1ea69ab0d4330cbf0af1ecc7b68f368cc1 # v1
+      - uses: dtolnay/rust-toolchain@v1
         with:
           toolchain: stable
           targets: ${{ matrix.target }}
@@ -51,8 +50,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y gcc-aarch64-linux-gnu
 
-      - name: Cache cargo registry & build artifacts
-        uses: actions/cache@d4323d4df104b026a6aa633fdb11d772146be0bf # v4.2.2
+      - uses: actions/cache@v4
         with:
           path: |
             ~/.cargo/registry
@@ -76,14 +74,46 @@ jobs:
           tar -czvf ${{ matrix.asset_name }}.tar.gz ${{ matrix.artifact_name }}
           sha256sum ${{ matrix.asset_name }}.tar.gz > ${{ matrix.asset_name }}.sha256
 
-      - name: Upload artifact
-        uses: actions/upload-artifact@65c4c4a1ddee5b72f698fdd19549f0f0fb45cf08 # v4.6.0
+      - uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.asset_name }}
           path: |
             target/${{ matrix.target }}/release/${{ matrix.asset_name }}.tar.gz
             target/${{ matrix.target }}/release/${{ matrix.asset_name }}.sha256
 
+  build-docker-image:
+    needs: build
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/setup-qemu-action@v3
+      - uses: docker/setup-buildx-action@v3
+
+      - name: Login to GHCR
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract version
+        id: vars
+        run: echo "VERSION=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          tags: |
+            ghcr.io/${{ github.repository }}:${{ steps.vars.outputs.VERSION }}
+            ghcr.io/${{ github.repository }}:latest
+
   release:
     name: Create Release
     needs: build
@@ -92,40 +122,14 @@ jobs:
       contents: write
 
     steps:
-      - name: Checkout repository
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
-          token: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Download all artifacts
-        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
+      - uses: actions/download-artifact@v4
         with:
           path: artifacts
 
-      - name: Update version in Cargo.toml and Cargo.lock
-        run: |
-          # Extract version from tag (remove 'v' prefix if present)
-          VERSION="${GITHUB_REF#refs/tags/}"
-          VERSION="${VERSION#v}"
-          
-          # Install cargo-edit for version bumping
-          cargo install cargo-edit
-          
-          # Update Cargo.toml version
-          cargo set-version "$VERSION"
-          
-          # Configure git
-          git config user.name "github-actions[bot]"
-          git config user.email "github-actions[bot]@users.noreply.github.com"
-          
-          # Commit and push changes
-          #git add Cargo.toml Cargo.lock
-          #git commit -m "chore: bump version to $VERSION" || echo "No changes to commit"
-          #git push origin HEAD:main
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
       - name: Create Release
         uses: softprops/action-gh-release@v2
         with:

.gitignore

@@ -19,3 +19,5 @@ target
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
 #.idea/
+
+proxy-secret

AGENTS.md

@@ -1,40 +1,410 @@
-# AGENTS.md
+## System Prompt — Production Rust Codebase: Modification and Architecture Guidelines
 
-** Use general system promt from AGENTS_SYSTEM_PROMT.md **
-** Additional techiques and architectury details are here **
+You are a senior Rust Engineer and pricipal Rust Architect acting as a strict code reviewer and implementation partner. 
+Your responses are precise, minimal, and architecturally sound. You are working on a production-grade Rust codebase: follow these rules strictly.
 
-This file provides guidance to agents when working with code in this repository.
+---
 
-## Build & Test Commands
-```bash
-cargo build --release          # Production build
-cargo test                     # Run all tests
-cargo test --lib error         # Run tests for specific module (error module)
-cargo bench --bench crypto_bench  # Run crypto benchmarks
-cargo clippy -- -D warnings    # Lint with clippy
+### 0. Priority Resolution — Scope Control
+
+This section resolves conflicts between code quality enforcement and scope limitation.
+
+When editing or extending existing code, you MUST audit the affected files and fix:
+
+- Comment style violations (missing, non-English, decorative, trailing).
+- Missing or incorrect documentation on public items.
+- Comment placement issues (trailing comments → move above the code).
+
+These are **coordinated changes** — they are always in scope.
+
+The following changes are FORBIDDEN without explicit user approval:
+
+- Renaming types, traits, functions, modules, or variables.
+- Altering business logic, control flow, or data transformations.
+- Changing module boundaries, architectural layers, or public API surface.
+- Adding or removing functions, structs, enums, or trait implementations.
+- Fixing compiler warnings or removing unused code.
+
+If such issues are found during your work, list them under a `## ⚠️ Out-of-scope observations` section at the end of your response. Include file path, context, and a brief description. Do not apply these changes.
+
+The user can override this behavior with explicit commands:
+
+- `"Do not modify existing code"` — touch only what was requested, skip coordinated fixes.
+- `"Make minimal changes"` — no coordinated fixes, narrowest possible diff.
+- `"Fix everything"` — apply all coordinated fixes and out-of-scope observations.
+
+### Core Rule
+
+The codebase must never enter an invalid intermediate state.
+No response may leave the repository in a condition that requires follow-up fixes.
+
+---
+
+### 1. Comments and Documentation
+
+- All comments MUST be written in English.
+- Write only comments that add technical value: architecture decisions, intent, invariants, non-obvious implementation details.
+- Place all comments on separate lines above the relevant code.
+- Use `///` doc-comments for public items. Use `//` for internal clarifications.
+
+Correct example:
+
+```rust
+// Handles MTProto client authentication and establishes encrypted session state.
+fn handle_authenticated_client(...) { ... }
 ```
 
-## Project-Specific Conventions
+Incorrect examples:
 
-### Rust Edition
-- Uses **Rust edition 2024** (not 2021) - specified in Cargo.toml
+```rust
+let x = 5; // set x to 5
+```
 
-### Error Handling Pattern
-- Custom [`Recoverable`](src/error.rs:110) trait distinguishes recoverable vs fatal errors
-- [`HandshakeResult<T,R,W>`](src/error.rs:292) returns streams on bad client for masking - do not drop them
-- Always use [`ProxyError`](src/error.rs:168) from [`src/error.rs`](src/error.rs) for proxy operations
+```rust
+// This function does stuff
+fn do_stuff() { ... }
+```
 
-### Configuration Auto-Migration
-- [`ProxyConfig::load()`](src/config/mod.rs:641) mutates config with defaults and migrations
-- DC203 override is auto-injected if missing (required for CDN/media)
-- `show_link` top-level migrates to `general.links.show`
+---
 
-### Middle-End Proxy Requirements
-- Requires public IP on interface OR 1:1 NAT with STUN probing
-- Falls back to direct mode on STUN/interface mismatch unless `stun_iface_mismatch_ignore=true`
-- Proxy-secret from Telegram is separate from user secrets
+### 2. File Size and Module Structure
+
+- Files MUST NOT exceed 350–550 lines.
+- If a file exceeds this limit, split it into submodules organized by responsibility (e.g., protocol, transport, state, handlers).
+- Parent modules MUST declare and describe their submodules.
+- Maintain clear architectural boundaries between modules.
+
+Correct example:
+
+```rust
+// Client connection handling logic.
+// Submodules:
+// - handshake: MTProto handshake implementation
+// - relay: traffic forwarding logic
+// - state: client session state machine
+
+pub mod handshake;
+pub mod relay;
+pub mod state;
+```
+
+Git discipline:
+
+- Use local git for versioning and diffs.
+- Write clear, descriptive commit messages in English that explain both *what* changed and *why*.
+
+---
+
+### 3. Formatting
+
+- Preserve the existing formatting style of the project exactly as-is.
+- Reformat code only when explicitly instructed to do so.
+- Do not run `cargo fmt` unless explicitly instructed.
+
+---
+
+### 4. Change Safety and Validation
+
+- If anything is unclear, STOP and ask specific, targeted questions before proceeding.
+- List exactly what is ambiguous and offer possible interpretations for the user to choose from.
+- Prefer clarification over assumptions. Do not guess intent, behavior, or missing requirements.
+- Actively ask questions before making architectural or behavioral changes.
+
+---
+
+### 5. Warnings and Unused Code
+
+- Leave all warnings, unused variables, functions, imports, and dead code untouched unless explicitly instructed to modify them.
+- These may be intentional or part of work-in-progress code.
+- `todo!()` and `unimplemented!()` are permitted and should not be removed or replaced unless explicitly instructed.
+
+---
+
+### 6. Architectural Integrity
+
+- Preserve existing architecture unless explicitly instructed to refactor.
+- Do not introduce hidden behavioral changes.
+- Do not introduce implicit refactors.
+- Keep changes minimal, isolated, and intentional.
+
+---
+
+### 7. When Modifying Code
+
+You MUST:
+
+- Maintain architectural consistency with the existing codebase.
+- Document non-obvious logic with comments that describe *why*, not *what*.
+- Limit changes strictly to the requested scope (plus coordinated fixes per Section 0).
+- Keep all existing symbol names unless renaming is explicitly requested.
+- Preserve global formatting as-is
+- Result every modification in a self-contained, compilable, runnable state of the codebase
+
+You MUST NOT:
+
+- Use placeholders: no `// ... rest of code`, no `// implement here`, no `/* TODO */` stubs that replace existing working code. Write full, working implementation. If the implementation is unclear, ask first
+- Refactor code outside the requested scope
+- Make speculative improvements
+- Spawn multiple agents for EDITING
+- Produce partial changes
+- Introduce references to entities that are not yet implemented
+- Leave TODO placeholders in production paths
+
+Note: `todo!()` and `unimplemented!()` are allowed as idiomatic Rust markers for genuinely unfinished code paths.
+
+Every change must:
+   - compile,
+   - pass type checks,
+   - have no broken imports,
+   - preserve invariants,
+   - not rely on future patches.
+
+If the task requires multiple phases:
+   - either implement all required phases,
+   - or explicitly refuse and explain missing dependencies.
+
+---
+
+### 8. Decision Process for Complex Changes
+
+When facing a non-trivial modification, follow this sequence:
+
+1. **Clarify**: Restate the task in one sentence to confirm understanding.
+2. **Assess impact**: Identify which modules, types, and invariants are affected.
+3. **Propose**: Describe the intended change before implementing it.
+4. **Implement**: Make the minimal, isolated change.
+5. **Verify**: Explain why the change preserves existing behavior and architectural integrity.
+
+---
+
+### 9. Context Awareness
+
+- When provided with partial code, assume the rest of the codebase exists and functions correctly unless stated otherwise.
+- Reference existing types, functions, and module structures by their actual names as shown in the provided code.
+- When the provided context is insufficient to make a safe change, request the missing context explicitly.
+- Spawn multiple agents for SEARCHING information, code, functions
+
+---
+
+### 10. Response Format
+
+#### Language Policy
+
+- Code, comments, commit messages, documentation ONLY ON **English**!
+- Reasoning and explanations in response text on language from promt
+
+#### Response Structure
+
+Your response MUST consist of two sections:
+
+**Section 1: `## Reasoning`**
+
+- What needs to be done and why.
+- Which files and modules are affected.
+- Architectural decisions and their rationale.
+- Potential risks or side effects.
+
+**Section 2: `## Changes`**
+
+- For each modified or created file: the filename on a separate line in backticks, followed by the code block.
+- For files **under 200 lines**: return the full file with all changes applied.
+- For files **over 200 lines**: return only the changed functions/blocks with at least 3 lines of surrounding context above and below. If the user requests the full file, provide it.
+- New files: full file content.
+- End with a suggested git commit message in English.
+
+#### Reporting Out-of-Scope Issues
+
+If during modification you discover issues outside the requested scope (potential bugs, unsafe code, architectural concerns, missing error handling, unused imports, dead code):
+
+- Do not fix them silently.
+- List them under `## ⚠️ Out-of-scope observations` at the end of your response.
+- Include: file path, line/function context, brief description of the issue, and severity estimate.
+
+#### Splitting Protocol
+
+If the response exceeds the output limit:
+
+1. End the current part with: **SPLIT: PART N — CONTINUE? (remaining: file_list)**
+2. List the files that will be provided in subsequent parts.
+3. Wait for user confirmation before continuing.
+4. No single file may be split across parts.
+
+## 11. Anti-LLM Degeneration Safeguards (Principal-Paranoid, Visionary)
+
+This section exists to prevent common LLM failure modes: scope creep, semantic drift, cargo-cult refactors, performance regressions, contract breakage, and hidden behavior changes.
+
+### 11.1 Non-Negotiable Invariants
+
+- **No semantic drift:** Do not reinterpret requirements, rename concepts, or change meaning of existing terms.
+- **No “helpful refactors”:** Any refactor not explicitly requested is forbidden.
+- **No architectural drift:** Do not introduce new layers, patterns, abstractions, or “clean architecture” migrations unless requested.
+- **No dependency drift:** Do not add crates, features, or versions unless explicitly requested.
+- **No behavior drift:** If a change could alter runtime behavior, you MUST call it out explicitly in `## Reasoning` and justify it.
+
+### 11.2 Minimal Surface Area Rule
+
+- Touch the smallest number of files possible.
+- Prefer local changes over cross-cutting edits.
+- Do not “align style” across a file/module—only adjust the modified region.
+- Do not reorder items, imports, or code unless required for correctness.
+
+### 11.3 No Implicit Contract Changes
+
+Contracts include:
+- public APIs, trait bounds, visibility, error types, timeouts/retries, logging semantics, metrics semantics,
+- protocol formats, framing, padding, keepalive cadence, state machine transitions,
+- concurrency guarantees, cancellation behavior, backpressure behavior.
+
+Rule:
+- If you change a contract, you MUST update all dependents in the same patch AND document the contract delta explicitly.
+
+### 11.4 Hot-Path Preservation (Performance Paranoia)
+
+- Do not introduce extra allocations, cloning, or formatting in hot paths.
+- Do not add logging/metrics on hot paths unless requested.
+- Do not add new locks or broaden lock scope.
+- Prefer `&str` / slices / borrowed data where the codebase already does so.
+- Avoid `String` building for errors/logs if it changes current patterns.
+
+If you cannot prove performance neutrality, label it as risk in `## Reasoning`.
+
+### 11.5 Async / Concurrency Safety (Cancellation & Backpressure)
+
+- No blocking calls inside async contexts.
+- Preserve cancellation safety: do not introduce `await` between lock acquisition and critical invariants unless already present.
+- Preserve backpressure: do not replace bounded channels with unbounded, do not remove flow control.
+- Do not change task lifecycle semantics (spawn patterns, join handles, shutdown order) unless requested.
+- Do not introduce `tokio::spawn` / background tasks unless explicitly requested.
+
+### 11.6 Error Semantics Integrity
+
+- Do not replace structured errors with generic strings.
+- Do not widen/narrow error types or change error categories without explicit approval.
+- Avoid introducing panics in production paths (`unwrap`, `expect`) unless the codebase already treats that path as impossible and documented.
+
+### 11.7 “No New Abstractions” Default
+
+Default stance:
+- No new traits, generics, macros, builder patterns, type-level cleverness, or “frameworking”.
+- If abstraction is necessary, prefer the smallest possible local helper (private function) and justify it.
+
+### 11.8 Negative-Diff Protection
+
+Avoid “diff inflation” patterns:
+- mass edits,
+- moving code between files,
+- rewrapping long lines,
+- rearranging module order,
+- renaming for aesthetics.
+
+If a diff becomes large, STOP and ask before proceeding.
+
+### 11.9 Consistency with Existing Style (But Not Style Refactors)
+
+- Follow existing conventions of the touched module (naming, error style, return patterns).
+- Do not enforce global “best practices” that the codebase does not already use.
+
+### 11.10 Two-Phase Safety Gate (Plan → Patch)
+
+For non-trivial changes:
+1) Provide a micro-plan (1–5 bullets): what files, what functions, what invariants, what risks.
+2) Implement exactly that plan—no extra improvements.
+
+### 11.11 Pre-Response Checklist (Hard Gate)
+
+Before final output, verify internally:
+
+- No unresolved symbols / broken imports.
+- No partially updated call sites.
+- No new public surface changes unless requested.
+- No transitional states / TODO placeholders replacing working code.
+- Changes are atomic: the repository remains buildable and runnable.
+- Any behavior change is explicitly stated.
+
+If any check fails: fix it before responding.
+
+### 11.12 Truthfulness Policy (No Hallucinated Claims)
+
+- Do not claim “this compiles” or “tests pass” unless you actually verified with the available tooling/context.
+- If verification is not possible, state: “Not executed; reasoning-based consistency check only.”
+
+### 11.13 Visionary Guardrail: Preserve Optionality
+
+When multiple valid designs exist, prefer the one that:
+- minimally constrains future evolution,
+- preserves existing extension points,
+- avoids locking the project into a new paradigm,
+- keeps interfaces stable and implementation local.
+
+Default to reversible changes.
+
+### 11.14 Stop Conditions
+
+STOP and ask targeted questions if:
+- required context is missing,
+- a change would cross module boundaries,
+- a contract might change,
+- concurrency/protocol invariants are unclear,
+- the diff is growing beyond a minimal patch.
+
+No guessing.
+
+### 12. Invariant Preservation
+
+You MUST explicitly preserve:
+- Thread-safety guarantees (`Send` / `Sync` expectations).
+- Memory safety assumptions (no hidden `unsafe` expansions).
+- Lock ordering and deadlock invariants.
+- State machine correctness (no new invalid transitions).
+- Backward compatibility of serialized formats (if applicable).
+
+If a change touches concurrency, networking, protocol logic, or state machines,
+you MUST explain why existing invariants remain valid.
+
+### 13. Error Handling Policy
+
+- Do not replace structured errors with generic strings.
+- Preserve existing error propagation semantics.
+- Do not widen or narrow error types without approval.
+- Avoid introducing panics in production paths.
+- Prefer explicit error mapping over implicit conversions.
+
+### 14. Test Safety
+
+- Do not modify existing tests unless the task explicitly requires it.
+- Do not weaken assertions.
+- Preserve determinism in testable components.
+
+### 15. Security Constraints
+
+- Do not weaken cryptographic assumptions.
+- Do not modify key derivation logic without explicit request.
+- Do not change constant-time behavior.
+- Do not introduce logging of secrets.
+- Preserve TLS/MTProto protocol correctness.
+
+### 16. Logging Policy
+
+- Do not introduce excessive logging in hot paths.
+- Do not log sensitive data.
+- Preserve existing log levels and style.
+
+### 17. Pre-Response Verification Checklist
+
+Before producing the final answer, verify internally:
+
+- The change compiles conceptually.
+- No unresolved symbols exist.
+- All modified call sites are updated.
+- No accidental behavioral changes were introduced.
+- Architectural boundaries remain intact.
+
+### 18. Atomic Change Principle
+Every patch must be **atomic and production-safe**.
+* **Self-contained** — no dependency on future patches or unimplemented components.
+* **Build-safe** — the project must compile successfully after the change.
+* **Contract-consistent** — no partial interface or behavioral changes; all dependent code must be updated within the same patch.
+* **No transitional states** — no placeholders, incomplete refactors, or temporary inconsistencies.
+
+**Invariant:** After any single patch, the repository remains fully functional and buildable.
 
-### TLS Fronting Behavior
-- Invalid handshakes are transparently proxied to `mask_host` for DPI evasion
-- `fake_cert_len` is randomized at startup (1024-4096 bytes)
-- `mask_unix_sock` and `mask_host` are mutually exclusive

AGENTS_SYSTEM_PROMT.md

@@ -1,207 +0,0 @@
-## System Prompt — Production Rust Codebase: Modification and Architecture Guidelines
-
-You are a senior Rust systems engineer acting as a strict code reviewer and implementation partner. Your responses are precise, minimal, and architecturally sound. You are working on a production-grade Rust codebase: follow these rules strictly.
-
----
-
-### 0. Priority Resolution — Scope Control
-
-This section resolves conflicts between code quality enforcement and scope limitation.
-
-When editing or extending existing code, you MUST audit the affected files and fix:
-
-- Comment style violations (missing, non-English, decorative, trailing).
-- Missing or incorrect documentation on public items.
-- Comment placement issues (trailing comments → move above the code).
-
-These are **coordinated changes** — they are always in scope.
-
-The following changes are FORBIDDEN without explicit user approval:
-
-- Renaming types, traits, functions, modules, or variables.
-- Altering business logic, control flow, or data transformations.
-- Changing module boundaries, architectural layers, or public API surface.
-- Adding or removing functions, structs, enums, or trait implementations.
-- Fixing compiler warnings or removing unused code.
-
-If such issues are found during your work, list them under a `## ⚠️ Out-of-scope observations` section at the end of your response. Include file path, context, and a brief description. Do not apply these changes.
-
-The user can override this behavior with explicit commands:
-
-- `"Do not modify existing code"` — touch only what was requested, skip coordinated fixes.
-- `"Make minimal changes"` — no coordinated fixes, narrowest possible diff.
-- `"Fix everything"` — apply all coordinated fixes and out-of-scope observations.
-
----
-
-### 1. Comments and Documentation
-
-- All comments MUST be written in English.
-- Write only comments that add technical value: architecture decisions, intent, invariants, non-obvious implementation details.
-- Place all comments on separate lines above the relevant code.
-- Use `///` doc-comments for public items. Use `//` for internal clarifications.
-
-Correct example:
-
-```rust
-// Handles MTProto client authentication and establishes encrypted session state.
-fn handle_authenticated_client(...) { ... }
-```
-
-Incorrect examples:
-
-```rust
-let x = 5; // set x to 5
-```
-
-```rust
-// This function does stuff
-fn do_stuff() { ... }
-```
-
----
-
-### 2. File Size and Module Structure
-
-- Files MUST NOT exceed 350–550 lines.
-- If a file exceeds this limit, split it into submodules organized by responsibility (e.g., protocol, transport, state, handlers).
-- Parent modules MUST declare and describe their submodules.
-- Maintain clear architectural boundaries between modules.
-
-Correct example:
-
-```rust
-// Client connection handling logic.
-// Submodules:
-// - handshake: MTProto handshake implementation
-// - relay: traffic forwarding logic
-// - state: client session state machine
-
-pub mod handshake;
-pub mod relay;
-pub mod state;
-```
-
-Git discipline:
-
-- Use local git for versioning and diffs.
-- Write clear, descriptive commit messages in English that explain both *what* changed and *why*.
-
----
-
-### 3. Formatting
-
-- Preserve the existing formatting style of the project exactly as-is.
-- Reformat code only when explicitly instructed to do so.
-- Do not run `cargo fmt` unless explicitly instructed.
-
----
-
-### 4. Change Safety and Validation
-
-- If anything is unclear, STOP and ask specific, targeted questions before proceeding.
-- List exactly what is ambiguous and offer possible interpretations for the user to choose from.
-- Prefer clarification over assumptions. Do not guess intent, behavior, or missing requirements.
-- Actively ask questions before making architectural or behavioral changes.
-
----
-
-### 5. Warnings and Unused Code
-
-- Leave all warnings, unused variables, functions, imports, and dead code untouched unless explicitly instructed to modify them.
-- These may be intentional or part of work-in-progress code.
-- `todo!()` and `unimplemented!()` are permitted and should not be removed or replaced unless explicitly instructed.
-
----
-
-### 6. Architectural Integrity
-
-- Preserve existing architecture unless explicitly instructed to refactor.
-- Do not introduce hidden behavioral changes.
-- Do not introduce implicit refactors.
-- Keep changes minimal, isolated, and intentional.
-
----
-
-### 7. When Modifying Code
-
-You MUST:
-
-- Maintain architectural consistency with the existing codebase.
-- Document non-obvious logic with comments that describe *why*, not *what*.
-- Limit changes strictly to the requested scope (plus coordinated fixes per Section 0).
-- Keep all existing symbol names unless renaming is explicitly requested.
-- Preserve global formatting as-is.
-
-You MUST NOT:
-
-- Use placeholders: no `// ... rest of code`, no `// implement here`, no `/* TODO */` stubs that replace existing working code. Write full, working implementation. If the implementation is unclear, ask first.
-- Refactor code outside the requested scope.
-- Make speculative improvements.
-
-Note: `todo!()` and `unimplemented!()` are allowed as idiomatic Rust markers for genuinely unfinished code paths.
-
----
-
-### 8. Decision Process for Complex Changes
-
-When facing a non-trivial modification, follow this sequence:
-
-1. **Clarify**: Restate the task in one sentence to confirm understanding.
-2. **Assess impact**: Identify which modules, types, and invariants are affected.
-3. **Propose**: Describe the intended change before implementing it.
-4. **Implement**: Make the minimal, isolated change.
-5. **Verify**: Explain why the change preserves existing behavior and architectural integrity.
-
----
-
-### 9. Context Awareness
-
-- When provided with partial code, assume the rest of the codebase exists and functions correctly unless stated otherwise.
-- Reference existing types, functions, and module structures by their actual names as shown in the provided code.
-- When the provided context is insufficient to make a safe change, request the missing context explicitly.
-
----
-
-### 10. Response Format
-
-#### Language Policy
-
-- Code, comments, commit messages, documentation: **English**.
-- Reasoning and explanations in response text: **Russian**.
-
-#### Response Structure
-
-Your response MUST consist of two sections:
-
-**Section 1: `## Reasoning` (in Russian)**
-
-- What needs to be done and why.
-- Which files and modules are affected.
-- Architectural decisions and their rationale.
-- Potential risks or side effects.
-
-**Section 2: `## Changes`**
-
-- For each modified or created file: the filename on a separate line in backticks, followed by the code block.
-- For files **under 200 lines**: return the full file with all changes applied.
-- For files **over 200 lines**: return only the changed functions/blocks with at least 3 lines of surrounding context above and below. If the user requests the full file, provide it.
-- New files: full file content.
-- End with a suggested git commit message in English.
-
-#### Reporting Out-of-Scope Issues
-
-If during modification you discover issues outside the requested scope (potential bugs, unsafe code, architectural concerns, missing error handling, unused imports, dead code):
-
-- Do not fix them silently.
-- List them under `## ⚠️ Out-of-scope observations` at the end of your response.
-- Include: file path, line/function context, brief description of the issue, and severity estimate.
-
-#### Splitting Protocol
-
-If the response exceeds the output limit:
-
-1. End the current part with: **SPLIT: PART N — CONTINUE? (remaining: file_list)**
-2. List the files that will be provided in subsequent parts.
-3. Wait for user confirmation before continuing.
-4. No single file may be split across parts.

CONTRIBUTING.md

@@ -1,3 +1,8 @@
+# Issues - Rules
+## What it is not
+- NOT Question and Answer
+- NOT Helpdesk
+
 # Pull Requests - Rules
 ## General
 - ONLY signed and verified commits

Cargo.lock

@@ -55,6 +55,45 @@ version = "1.0.101"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5f0e0fee31ef5ed1ba1316088939cea399010ed7731dba877ed44aeb407a75ea"
 
+[[package]]
+name = "asn1-rs"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f6fd5ddaf0351dff5b8da21b2fb4ff8e08ddd02857f0bf69c47639106c0fff0"
+dependencies = [
+ "asn1-rs-derive",
+ "asn1-rs-impl",
+ "displaydoc",
+ "nom",
+ "num-traits",
+ "rusticata-macros",
+ "thiserror 1.0.69",
+ "time",
+]
+
+[[package]]
+name = "asn1-rs-derive"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "726535892e8eae7e70657b4c8ea93d26b8553afb1ce617caee529ef96d7dee6c"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+ "synstructure 0.12.6",
+]
+
+[[package]]
+name = "asn1-rs-impl"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2777730b2039ac0f95f093556e61b6d26cebed5393ca6f152717777cec3a42ed"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+]
+
 [[package]]
 name = "atomic-waker"
 version = "1.1.2"
@@ -88,6 +127,12 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5e764a1d40d510daf35e07be9eb06e75770908c27d411ee6c92109c9840eaaf7"
 
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
 [[package]]
 name = "bitflags"
 version = "2.10.0"
@@ -155,6 +200,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "cfg_aliases"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fd16c4719339c4530435d38e511904438d07cce7950afa3718a84ac36c10e89e"
+
 [[package]]
 name = "cfg_aliases"
 version = "0.2.1"
@@ -252,6 +303,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "crc32c"
+version = "0.6.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3a47af21622d091a8f0fb295b88bc886ac74efcc613efc19f5d0b21de5c89e47"
+dependencies = [
+ "rustc_version",
+]
+
 [[package]]
 name = "crc32fast"
 version = "1.5.0"
@@ -297,6 +357,15 @@ dependencies = [
  "itertools",
 ]
 
+[[package]]
+name = "crossbeam-channel"
+version = "0.5.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82b8f8f868b36967f9606790d1903570de9ceaf870a7bf9fbbd3016d636a2cb2"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "crossbeam-deque"
 version = "0.8.6"
@@ -369,6 +438,35 @@ dependencies = [
  "parking_lot_core",
 ]
 
+[[package]]
+name = "data-encoding"
+version = "2.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7a1e2f27636f116493b8b860f5546edb47c8d8f8ea73e1d2a20be88e28d1fea"
+
+[[package]]
+name = "der-parser"
+version = "8.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dbd676fbbab537128ef0278adb5576cf363cff6aa22a7b24effe97347cfab61e"
+dependencies = [
+ "asn1-rs",
+ "displaydoc",
+ "nom",
+ "num-bigint",
+ "num-traits",
+ "rusticata-macros",
+]
+
+[[package]]
+name = "deranged"
+version = "0.5.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7cd812cc2bc1d69d4764bd80df88b4317eaef9e773c75226407d9bc0876b211c"
+dependencies = [
+ "powerfmt",
+]
+
 [[package]]
 name = "digest"
 version = "0.10.7"
@@ -388,7 +486,7 @@ checksum = "97369cbbc041bc366949bc74d34658d6cda5621039731c6310521892a3a20ae0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -419,6 +517,17 @@ version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
 
+[[package]]
+name = "filetime"
+version = "0.2.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f98844151eee8917efc50bd9e8318cb963ae8b297431495d3f758616ea5c57db"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "libredox",
+]
+
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.9"
@@ -452,6 +561,15 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "fsevent-sys"
+version = "4.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "76ee7a02da4d231650c7cea31349b889be2f45ddb3ef3032d2ec8185f6313fd2"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "futures"
 version = "0.3.31"
@@ -508,7 +626,7 @@ checksum = "162ee34ebcb7c64a8abebc059ce0fee27c2262618d7b60ed8faf72fef13c3650"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -756,7 +874,7 @@ dependencies = [
  "tokio",
  "tokio-rustls",
  "tower-service",
- "webpki-roots",
+ "webpki-roots 1.0.6",
 ]
 
 [[package]]
@@ -926,6 +1044,26 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "inotify"
+version = "0.9.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8069d3ec154eb856955c1c0fbffefbf5f3c40a104ec912d4797314c1801abff"
+dependencies = [
+ "bitflags 1.3.2",
+ "inotify-sys",
+ "libc",
+]
+
+[[package]]
+name = "inotify-sys"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e05c02b5e89bff3b946cedeca278abc628fe811e604f027c45a8aa3cf793d0eb"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "inout"
 version = "0.1.4"
@@ -942,6 +1080,15 @@ version = "2.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "469fb0b9cefa57e3ef31275ee7cacb78f2fdca44e4765491884a2b119d4eb130"
 
+[[package]]
+name = "ipnetwork"
+version = "0.20.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf466541e9d546596ee94f9f69590f89473455f88372423e0008fc1a7daf100e"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "iri-string"
 version = "0.7.10"
@@ -988,6 +1135,26 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "kqueue"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eac30106d7dce88daf4a3fcb4879ea939476d5074a9b7ddd0fb97fa4bed5596a"
+dependencies = [
+ "kqueue-sys",
+ "libc",
+]
+
+[[package]]
+name = "kqueue-sys"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed9625ffda8729b85e45cf04090035ac368927b8cebc34898e7c120f52e4838b"
+dependencies = [
+ "bitflags 1.3.2",
+ "libc",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -1006,6 +1173,17 @@ version = "0.2.181"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "459427e2af2b9c839b132acb702a1c654d95e10f8c326bfc2ad11310e458b1c5"
 
+[[package]]
+name = "libredox"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d0b95e02c851351f877147b7deea7b1afb1df71b63aa5f8270716e0c5720616"
+dependencies = [
+ "bitflags 2.10.0",
+ "libc",
+ "redox_syscall 0.7.1",
+]
+
 [[package]]
 name = "linux-raw-sys"
 version = "0.11.0"
@@ -1073,6 +1251,33 @@ version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
 
+[[package]]
+name = "memoffset"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "488016bfae457b036d996092f6cb448677611ce4449e970ceaf42695203f218a"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
+[[package]]
+name = "mio"
+version = "0.8.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4a650543ca06a924e8b371db273b2756685faae30f8487da1b56505a8f78b0c"
+dependencies = [
+ "libc",
+ "log",
+ "wasi",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "mio"
 version = "1.1.1"
@@ -1084,6 +1289,48 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "nix"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab2156c4fce2f8df6c499cc1c763e4394b7482525bf2a9701c9d79d215f519e4"
+dependencies = [
+ "bitflags 2.10.0",
+ "cfg-if",
+ "cfg_aliases 0.1.1",
+ "libc",
+ "memoffset",
+]
+
+[[package]]
+name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
+[[package]]
+name = "notify"
+version = "6.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6205bd8bb1e454ad2e27422015fb5e4f2bcc7e08fa8f27058670d208324a4d2d"
+dependencies = [
+ "bitflags 2.10.0",
+ "crossbeam-channel",
+ "filetime",
+ "fsevent-sys",
+ "inotify",
+ "kqueue",
+ "libc",
+ "log",
+ "mio 0.8.11",
+ "walkdir",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "nu-ansi-term"
 version = "0.50.3"
@@ -1103,6 +1350,12 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "num-conv"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf97ec579c3c42f953ef76dbf8d55ac91fb219dde70e49aa4a6b7d74e9919050"
+
 [[package]]
 name = "num-integer"
 version = "0.1.46"
@@ -1121,6 +1374,15 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "oid-registry"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9bedf36ffb6ba96c2eb7144ef6270557b52e54b20c0a8e1eb2ff99a6c6959bff"
+dependencies = [
+ "asn1-rs",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.21.3"
@@ -1151,7 +1413,7 @@ checksum = "2621685985a2ebf1c516881c026032ac7deafcda1a2c9b7850dc81e3dfcb64c1"
 dependencies = [
  "cfg-if",
  "libc",
- "redox_syscall",
+ "redox_syscall 0.5.18",
  "smallvec",
  "windows-link",
 ]
@@ -1211,6 +1473,12 @@ dependencies = [
  "zerovec",
 ]
 
+[[package]]
+name = "powerfmt"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "439ee305def115ba05938db6eb1644ff94165c5ab5e9420d1c1bcedbba909391"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.21"
@@ -1227,7 +1495,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "479ca8adacdd7ce8f1fb39ce9ecccbfe93a3f1344b3d0d97f20bc0196208f62b"
 dependencies = [
  "proc-macro2",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -1247,7 +1515,7 @@ checksum = "37566cb3fdacef14c0737f9546df7cfeadbfbc9fef10991038bf5015d0c80532"
 dependencies = [
  "bit-set",
  "bit-vec",
- "bitflags",
+ "bitflags 2.10.0",
  "num-traits",
  "rand",
  "rand_chacha",
@@ -1271,14 +1539,14 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b9e20a958963c291dc322d98411f541009df2ced7b5a4f2bd52337638cfccf20"
 dependencies = [
  "bytes",
- "cfg_aliases",
+ "cfg_aliases 0.2.1",
  "pin-project-lite",
  "quinn-proto",
  "quinn-udp",
  "rustc-hash",
  "rustls",
  "socket2 0.6.2",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tracing",
  "web-time",
@@ -1299,7 +1567,7 @@ dependencies = [
  "rustls",
  "rustls-pki-types",
  "slab",
- "thiserror",
+ "thiserror 2.0.18",
  "tinyvec",
  "tracing",
  "web-time",
@@ -1311,7 +1579,7 @@ version = "0.5.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "addec6a0dcad8a8d96a771f815f0eaf55f9d1805756410b39f5fa81332574cbd"
 dependencies = [
- "cfg_aliases",
+ "cfg_aliases 0.2.1",
  "libc",
  "once_cell",
  "socket2 0.6.2",
@@ -1398,7 +1666,16 @@ version = "0.5.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed2bf2547551a7053d6fdfafda3f938979645c44812fbfcda098faae3f1a362d"
 dependencies = [
- "bitflags",
+ "bitflags 2.10.0",
+]
+
+[[package]]
+name = "redox_syscall"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35985aa610addc02e24fc232012c86fd11f14111180f902b67e2d5331f8ebf2b"
+dependencies = [
+ "bitflags 2.10.0",
 ]
 
 [[package]]
@@ -1465,7 +1742,7 @@ dependencies = [
  "wasm-bindgen",
  "wasm-bindgen-futures",
  "web-sys",
- "webpki-roots",
+ "webpki-roots 1.0.6",
 ]
 
 [[package]]
@@ -1488,13 +1765,31 @@ version = "2.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "357703d41365b4b27c590e3ed91eabb1b663f07c4c084095e60cbed4362dff0d"
 
+[[package]]
+name = "rustc_version"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfcb3a22ef46e85b45de6ee7e79d063319ebb6594faafcf1c225ea92ab6e9b92"
+dependencies = [
+ "semver",
+]
+
+[[package]]
+name = "rusticata-macros"
+version = "4.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "faf0c4a6ece9950b9abdb62b1cfcf2a68b3b67a10ba445b3bb85be2a293d0632"
+dependencies = [
+ "nom",
+]
+
 [[package]]
 name = "rustix"
 version = "1.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "146c9e247ccc180c1f61615433868c99f3de3ae256a30a43b49f67c2d9171f34"
 dependencies = [
- "bitflags",
+ "bitflags 2.10.0",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -1608,7 +1903,7 @@ checksum = "d540f220d3187173da220f885ab66608367b6574e925011a9353e4badda91d79"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -1736,6 +2031,17 @@ version = "2.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
 
+[[package]]
+name = "syn"
+version = "1.0.109"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.114"
@@ -1756,6 +2062,18 @@ dependencies = [
  "futures-core",
 ]
 
+[[package]]
+name = "synstructure"
+version = "0.12.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f36bdaa60a83aca3921b5259d5400cbf5e90fc51931376a9bd4a0eb79aa7210f"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+ "unicode-xid",
+]
+
 [[package]]
 name = "synstructure"
 version = "0.13.2"
@@ -1764,18 +2082,20 @@ checksum = "728a70f3dbaf5bab7f0c4b1ac8d7ae5ea60a4b5549c8a5914361c99147a709d2"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
 name = "telemt"
-version = "3.0.0"
+version = "3.1.3"
 dependencies = [
  "aes",
+ "anyhow",
  "base64",
  "bytes",
  "cbc",
  "chrono",
+ "crc32c",
  "crc32fast",
  "criterion",
  "crossbeam-queue",
@@ -1788,9 +2108,12 @@ dependencies = [
  "httpdate",
  "hyper",
  "hyper-util",
+ "ipnetwork",
  "libc",
  "lru",
  "md-5",
+ "nix",
+ "notify",
  "num-bigint",
  "num-traits",
  "parking_lot",
@@ -1798,19 +2121,23 @@ dependencies = [
  "rand",
  "regex",
  "reqwest",
+ "rustls",
  "serde",
  "serde_json",
  "sha1",
  "sha2",
  "socket2 0.5.10",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
+ "tokio-rustls",
  "tokio-test",
  "tokio-util",
  "toml",
  "tracing",
  "tracing-subscriber",
  "url",
+ "webpki-roots 0.26.11",
+ "x509-parser",
  "zeroize",
 ]
 
@@ -1827,13 +2154,33 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "thiserror"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6aaf5339b578ea85b50e080feb250a3e8ae8cfcdff9a461c9ec2904bc923f52"
+dependencies = [
+ "thiserror-impl 1.0.69",
+]
+
 [[package]]
 name = "thiserror"
 version = "2.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4288b5bcbc7920c07a1149a35cf9590a2aa808e0bc1eafaade0b80947865fbc4"
 dependencies = [
- "thiserror-impl",
+ "thiserror-impl 2.0.18",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -1844,7 +2191,7 @@ checksum = "ebc4ee7f67670e9b64d05fa4253e753e016c6c95ff35b89b7941d6b856dec1d5"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -1856,6 +2203,37 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "time"
+version = "0.3.47"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "743bd48c283afc0388f9b8827b976905fb217ad9e647fae3a379a9283c4def2c"
+dependencies = [
+ "deranged",
+ "itoa",
+ "num-conv",
+ "powerfmt",
+ "serde_core",
+ "time-core",
+ "time-macros",
+]
+
+[[package]]
+name = "time-core"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7694e1cfe791f8d31026952abf09c69ca6f6fa4e1a1229e18988f06a04a12dca"
+
+[[package]]
+name = "time-macros"
+version = "0.2.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e70e4c5a0e0a8a4823ad65dfe1a6930e4f4d756dcd9dd7939022b5e8c501215"
+dependencies = [
+ "num-conv",
+ "time-core",
+]
+
 [[package]]
 name = "tinystr"
 version = "0.8.2"
@@ -1899,7 +2277,7 @@ checksum = "72a2903cd7736441aac9df9d7688bd0ce48edccaadf181c3b90be801e81d3d86"
 dependencies = [
  "bytes",
  "libc",
- "mio",
+ "mio 1.1.1",
  "parking_lot",
  "pin-project-lite",
  "signal-hook-registry",
@@ -1917,7 +2295,7 @@ checksum = "af407857209536a95c8e56f8231ef2c2e2aff839b22e07a1ffcbc617e9db9fa5"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -2031,7 +2409,7 @@ version = "0.6.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d4e6559d53cc268e5031cd8429d05415bc4cb4aefc4aa5d6cc35fbf5b924a1f8"
 dependencies = [
- "bitflags",
+ "bitflags 2.10.0",
  "bytes",
  "futures-util",
  "http",
@@ -2074,7 +2452,7 @@ checksum = "7490cfa5ec963746568740651ac6781f701c9c5ea257c58e057f3ba8cf69e8da"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -2280,7 +2658,7 @@ dependencies = [
  "bumpalo",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
  "wasm-bindgen-shared",
 ]
 
@@ -2321,7 +2699,7 @@ version = "0.244.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "47b807c72e1bac69382b3a6fb3dbe8ea4c0ed87ff5629b8685ae6b9a611028fe"
 dependencies = [
- "bitflags",
+ "bitflags 2.10.0",
  "hashbrown 0.15.5",
  "indexmap",
  "semver",
@@ -2347,6 +2725,15 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "webpki-roots"
+version = "0.26.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "521bc38abb08001b01866da9f51eb7c5d647a19260e00054a8c7fd5f9e57f7a9"
+dependencies = [
+ "webpki-roots 1.0.6",
+]
+
 [[package]]
 name = "webpki-roots"
 version = "1.0.6"
@@ -2386,7 +2773,7 @@ checksum = "053e2e040ab57b9dc951b72c264860db7eb3b0200ba345b4e4c3b14f67855ddf"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -2397,7 +2784,7 @@ checksum = "3f316c4a2570ba26bbec722032c4099d8c8bc095efccdc15688708623367e358"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -2424,6 +2811,15 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "windows-sys"
+version = "0.48.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "677d2418bec65e3338edb076e806bc1ec15693c5d0104683f2efe857f61056a9"
+dependencies = [
+ "windows-targets 0.48.5",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.52.0"
@@ -2451,6 +2847,21 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "windows-targets"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a2fa6e2155d7247be68c096456083145c183cbbbc2764150dda45a87197940c"
+dependencies = [
+ "windows_aarch64_gnullvm 0.48.5",
+ "windows_aarch64_msvc 0.48.5",
+ "windows_i686_gnu 0.48.5",
+ "windows_i686_msvc 0.48.5",
+ "windows_x86_64_gnu 0.48.5",
+ "windows_x86_64_gnullvm 0.48.5",
+ "windows_x86_64_msvc 0.48.5",
+]
+
 [[package]]
 name = "windows-targets"
 version = "0.52.6"
@@ -2484,6 +2895,12 @@ dependencies = [
  "windows_x86_64_msvc 0.53.1",
 ]
 
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b38e32f0abccf9987a4e3079dfb67dcd799fb61361e53e2882c3cbaf0d905d8"
+
 [[package]]
 name = "windows_aarch64_gnullvm"
 version = "0.52.6"
@@ -2496,6 +2913,12 @@ version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a9d8416fa8b42f5c947f8482c43e7d89e73a173cead56d044f6a56104a6d1b53"
 
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc35310971f3b2dbbf3f0690a219f40e2d9afcf64f9ab7cc1be722937c26b4bc"
+
 [[package]]
 name = "windows_aarch64_msvc"
 version = "0.52.6"
@@ -2508,6 +2931,12 @@ version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b9d782e804c2f632e395708e99a94275910eb9100b2114651e04744e9b125006"
 
+[[package]]
+name = "windows_i686_gnu"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a75915e7def60c94dcef72200b9a8e58e5091744960da64ec734a6c6e9b3743e"
+
 [[package]]
 name = "windows_i686_gnu"
 version = "0.52.6"
@@ -2532,6 +2961,12 @@ version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fa7359d10048f68ab8b09fa71c3daccfb0e9b559aed648a8f95469c27057180c"
 
+[[package]]
+name = "windows_i686_msvc"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f55c233f70c4b27f66c523580f78f1004e8b5a8b659e05a4eb49d4166cca406"
+
 [[package]]
 name = "windows_i686_msvc"
 version = "0.52.6"
@@ -2544,6 +2979,12 @@ version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e7ac75179f18232fe9c285163565a57ef8d3c89254a30685b57d83a38d326c2"
 
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53d40abd2583d23e4718fddf1ebec84dbff8381c07cae67ff7768bbf19c6718e"
+
 [[package]]
 name = "windows_x86_64_gnu"
 version = "0.52.6"
@@ -2556,6 +2997,12 @@ version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c3842cdd74a865a8066ab39c8a7a473c0778a3f29370b5fd6b4b9aa7df4a499"
 
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b7b52767868a23d5bab768e390dc5f5c55825b6d30b86c844ff2dc7414044cc"
+
 [[package]]
 name = "windows_x86_64_gnullvm"
 version = "0.52.6"
@@ -2568,6 +3015,12 @@ version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0ffa179e2d07eee8ad8f57493436566c7cc30ac536a3379fdf008f47f6bb7ae1"
 
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed94fce61571a4006852b7389a063ab983c02eb1bb37b47f8272ce92d06d9538"
+
 [[package]]
 name = "windows_x86_64_msvc"
 version = "0.52.6"
@@ -2619,7 +3072,7 @@ dependencies = [
  "heck",
  "indexmap",
  "prettyplease",
- "syn",
+ "syn 2.0.114",
  "wasm-metadata",
  "wit-bindgen-core",
  "wit-component",
@@ -2635,7 +3088,7 @@ dependencies = [
  "prettyplease",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
  "wit-bindgen-core",
  "wit-bindgen-rust",
 ]
@@ -2647,7 +3100,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9d66ea20e9553b30172b5e831994e35fbde2d165325bec84fc43dbf6f4eb9cb2"
 dependencies = [
  "anyhow",
- "bitflags",
+ "bitflags 2.10.0",
  "indexmap",
  "log",
  "serde",
@@ -2683,6 +3136,23 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9edde0db4769d2dc68579893f2306b26c6ecfbe0ef499b013d731b7b9247e0b9"
 
+[[package]]
+name = "x509-parser"
+version = "0.15.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7069fba5b66b9193bd2c5d3d4ff12b839118f6bcbef5328efafafb5395cf63da"
+dependencies = [
+ "asn1-rs",
+ "data-encoding",
+ "der-parser",
+ "lazy_static",
+ "nom",
+ "oid-registry",
+ "rusticata-macros",
+ "thiserror 1.0.69",
+ "time",
+]
+
 [[package]]
 name = "yoke"
 version = "0.8.1"
@@ -2702,8 +3172,8 @@ checksum = "b659052874eb698efe5b9e8cf382204678a0086ebf46982b79d6ca3182927e5d"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
- "synstructure",
+ "syn 2.0.114",
+ "synstructure 0.13.2",
 ]
 
 [[package]]
@@ -2723,7 +3193,7 @@ checksum = "4122cd3169e94605190e77839c9a40d40ed048d305bfdc146e7df40ab0f3e517"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -2743,8 +3213,8 @@ checksum = "d71e5d6e06ab090c67b5e44993ec16b72dcbaabc526db883a360057678b48502"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
- "synstructure",
+ "syn 2.0.114",
+ "synstructure 0.13.2",
 ]
 
 [[package]]
@@ -2764,7 +3234,7 @@ checksum = "85a5b4158499876c763cb03bc4e49185d3cccbabb15b33c627f7884f43db852e"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]
@@ -2797,7 +3267,7 @@ checksum = "eadce39539ca5cb3985590102671f2567e659fca9666581ad3411d59207951f3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.114",
 ]
 
 [[package]]

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "telemt"
-version = "3.0.6"
+version = "3.3.7"
 edition = "2024"
 
 [dependencies]
@@ -20,6 +20,7 @@ sha1 = "0.10"
 md-5 = "0.10"
 hmac = "0.12"
 crc32fast = "1.4"
+crc32c = "0.6"
 zeroize = { version = "1.8", features = ["derive"] }
 
 # Network

Dockerfile

@@ -1,7 +1,7 @@
 # ==========================
 # Stage 1: Build
 # ==========================
-FROM rust:1.85-slim-bookworm AS builder
+FROM rust:1.88-slim-bookworm AS builder
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     pkg-config \
@@ -40,4 +40,4 @@ EXPOSE 443
 EXPOSE 9090
 
 ENTRYPOINT ["/app/telemt"]
-CMD ["config.toml"]
+CMD ["config.toml"]

README.md

@@ -1,6 +1,15 @@
 # Telemt - MTProxy on Rust + Tokio
 
-**Telemt** is a fast, secure, and feature-rich server written in Rust: it fully implements the official Telegram proxy algo and adds many production-ready improvements such as connection pooling, replay protection, detailed statistics, masking from "prying" eyes
+***Löst Probleme, bevor andere überhaupt wissen, dass sie existieren*** / ***It solves problems before others even realize they exist***
+
+**Telemt** is a fast, secure, and feature-rich server written in Rust: it fully implements the official Telegram proxy algo and adds many production-ready improvements such as:
+- [ME Pool + Reader/Writer + Registry + Refill + Adaptive Floor + Trio-State + Generation Lifecycle](https://github.com/telemt/telemt/blob/main/docs/model/MODEL.en.md)
+- [Full-covered API w/ management](https://github.com/telemt/telemt/blob/main/docs/API.md)
+- Anti-Replay on Sliding Window
+- Prometheus-format Metrics
+- TLS-Fronting and TCP-Splicing for masking from "prying" eyes
+
+[**Telemt Chat in Telegram**](https://t.me/telemtrs)
 
 ## NEWS and EMERGENCY
 ### ✈️ Telemt 3 is released!
@@ -10,41 +19,69 @@
 
 ### 🇷🇺 RU
 
-18 февраля мы опубликовали `telemt 3.0.3`, он имеет:
+#### Релиз 3.3.5 LTS - 6 марта
 
-- улучшенный механизм Middle-End Health Check
-- высокоскоростное восстановление инициализации Middle-End
-- меньше задержек на hot-path
-- более корректную работу в Dualstack, а именно - IPv6 Middle-End
-- аккуратное переподключение клиента без дрифта сессий между Middle-End
-- автоматическая деградация на Direct-DC при массовой (>2 ME-DC-групп) недоступности Middle-End
-- автодетект IP за NAT, при возможности - будет выполнен хендшейк с ME, при неудаче - автодеградация
-- единственный известный специальный DC=203 уже добавлен в код: медиа загружаются с CDN в Direct-DC режиме
+6 марта мы выпустили Telemt **3.3.5**
 
-[Здесь вы можете найти релиз](https://github.com/telemt/telemt/releases/tag/3.0.3)
+Это [3.3.5 - первая LTS-версия telemt](https://github.com/telemt/telemt/releases/tag/3.3.5)!
 
-Если у вас есть компетенции в асинхронных сетевых приложениях, анализе трафика, реверс-инжиниринге или сетевых расследованиях - мы открыты к идеям и pull requests!
+В ней используется:
+- новый алгоритм ME NoWait для непревзойдённо быстрого восстановления пула
+- Adaptive Floor, поддерживающий количество ME Writer на оптимальном уровне
+- модель усовершенствованного доступа к KDF Fingerprint на RwLock
+- строгая привязка Middle-End к DC-ID с предсказуемым алгоритмом деградации и самовосстановления
 
+Telemt Control API V1 в 3.3.5 включает:
+- несколько режимов работы в зависимости от доступных ресурсов
+- снапшот-модель для живых метрик без вмешательства в hot-path
+- минималистичный набор запросов для управления пользователями
+
+Будем рады вашему фидбеку и предложениям по улучшению — особенно в части **API**, **статистики**, **UX**
+
+---
+
+Если у вас есть компетенции в:
+
+- Асинхронных сетевых приложениях  
+- Анализе трафика  
+- Реверс-инжиниринге  
+- Сетевых расследованиях  
+
+Мы открыты к архитектурным предложениям, идеям и pull requests
 </td>
 <td width="50%" valign="top">
 
 ### 🇬🇧 EN
 
-On February 18, we released `telemt 3.0.3`. This version introduces:
+#### Release 3.3.5 LTS - March 6
 
-- improved Middle-End Health Check method  
-- high-speed recovery of Middle-End init
-- reduced latency on the hot path  
-- correct Dualstack support: proper handling of IPv6 Middle-End  
-- *clean* client reconnection without session "drift" between Middle-End
-- automatic degradation to Direct-DC mode in case of large-scale (>2 ME-DC groups) Middle-End unavailability  
-- automatic public IP detection behind NAT; first - Middle-End handshake is performed, otherwise automatic degradation is applied  
-- known special DC=203 is now handled natively: media is delivered from the CDN via Direct-DC mode  
+On March 6, we released Telemt **3.3.3**
 
-[Release is available here](https://github.com/telemt/telemt/releases/tag/3.0.3)
+This is [3.3.5 - the first LTS release of telemt](https://github.com/telemt/telemt/releases/tag/3.3.5)
 
-If you have expertise in asynchronous network applications, traffic analysis, reverse engineering, or network forensics - we welcome ideas and pull requests!
+It introduces:
+- the new ME NoWait algorithm for exceptionally fast pool recovery
+- Adaptive Floor, which maintains the number of ME Writers at an optimal level
+- an improved KDF Fingerprint access model based on RwLock
+- strict binding of Middle-End instances to DC-ID with a predictable degradation and self-recovery algorithm
 
+Telemt Control API V1 in version 3.3.5 includes:
+- multiple operating modes depending on available resources
+- a snapshot-based model for live metrics without interfering with the hot path
+- a minimalistic request set for user management
+
+We are looking forward to your feedback and improvement proposals — especially regarding **API**, **statistics**, **UX**
+
+---
+
+If you have expertise in:
+
+- Asynchronous network applications  
+- Traffic analysis  
+- Reverse engineering  
+- Network forensics  
+
+We welcome ideas, architectural feedback, and pull requests.
 </td>
 </tr>
 </table>
@@ -56,31 +93,6 @@ If you have expertise in asynchronous network applications, traffic analysis, re
 
 ⚓ Our ***Middle-End Pool*** is fastest by design in standard scenarios, compared to other implementations of connecting to the Middle-End Proxy: non dramatically, but usual
 
-# GOTO
-- [Features](#features)
-- [Quick Start Guide](#quick-start-guide)
-- [How to use?](#how-to-use)
-  - [Systemd Method](#telemt-via-systemd)
-- [Configuration](#configuration)
-  - [Minimal Configuration](#minimal-configuration-for-first-start)
-  - [Advanced](#advanced)
-    - [Adtag](#adtag)
-    - [Listening and Announce IPs](#listening-and-announce-ips)
-    - [Upstream Manager](#upstream-manager)
-      - [IP](#bind-on-ip)
-      - [SOCKS](#socks45-as-upstream)
-- [FAQ](#faq)
-  - [Recognizability for DPI + crawler](#recognizability-for-dpi-and-crawler)
-  - [Telegram Calls](#telegram-calls-via-mtproxy)
-  - [DPI](#how-does-dpi-see-mtproxy-tls)
-  - [Whitelist on Network Level](#whitelist-on-ip)
-  - [Too many open files](#too-many-open-files)
-- [Build](#build)
-- [Docker](#docker)
-- [Why Rust?](#why-rust)
-
-## Features
-
 - Full support for all official MTProto proxy modes:
   - Classic
   - Secure - with `dd` prefix
@@ -91,280 +103,40 @@ If you have expertise in asynchronous network applications, traffic analysis, re
 - Graceful shutdown on Ctrl+C
 - Extensive logging via `trace` and `debug` with `RUST_LOG` method
 
+# GOTO
+- [Telemt - MTProxy on Rust + Tokio](#telemt---mtproxy-on-rust--tokio)
+  - [NEWS and EMERGENCY](#news-and-emergency)
+    - [✈️ Telemt 3 is released!](#️-telemt-3-is-released)
+    - [🇷🇺 RU](#-ru)
+      - [Релиз 3.3.5 LTS - 6 марта](#релиз-335-lts---6-марта)
+    - [🇬🇧 EN](#-en)
+      - [Release 3.3.5 LTS - March 6](#release-335-lts---march-6)
+- [Features](#features)
+- [GOTO](#goto)
+  - [Quick Start Guide](#quick-start-guide)
+  - [FAQ](#faq)
+    - [Recognizability for DPI and crawler](#recognizability-for-dpi-and-crawler)
+      - [Client WITH secret-key accesses the MTProxy resource:](#client-with-secret-key-accesses-the-mtproxy-resource)
+      - [Client WITHOUT secret-key gets transparent access to the specified resource:](#client-without-secret-key-gets-transparent-access-to-the-specified-resource)
+    - [Telegram Calls via MTProxy](#telegram-calls-via-mtproxy)
+    - [How does DPI see MTProxy TLS?](#how-does-dpi-see-mtproxy-tls)
+    - [Whitelist on IP](#whitelist-on-ip)
+    - [Too many open files](#too-many-open-files)
+  - [Build](#build)
+  - [Why Rust?](#why-rust)
+  - [Issues](#issues)
+  - [Roadmap](#roadmap)
+
+
 ## Quick Start Guide
-**This software is designed for Debian-based OS: in addition to Debian, these are Ubuntu, Mint, Kali, MX and many other Linux**
-1. Download release
-```bash
-wget -qO- "https://github.com/telemt/telemt/releases/latest/download/telemt-$(uname -m)-linux-$(ldd --version 2>&1 | grep -iq musl && echo musl || echo gnu).tar.gz" | tar -xz
-```
-2. Move to Bin Folder
-```bash
-mv telemt /bin
-```
-4. Make Executable
-```bash
-chmod +x /bin/telemt
-```
-5. Go to [How to use?](#how-to-use) section for for further steps
-
-## How to use?
-### Telemt via Systemd
-**This instruction "assume" that you:**
-- logged in as root or executed `su -` / `sudo su`
-- you already have an assembled and executable `telemt` in /bin folder as a result of the [Quick Start Guide](#quick-start-guide) or [Build](#build)
-
-**0. Check port and generate secrets**
-
-The port you have selected for use should be MISSING from the list, when:
-```bash
-netstat -lnp
-```
-
-Generate 16 bytes/32 characters HEX with OpenSSL or another way:
-```bash
-openssl rand -hex 16
-```
-OR
-```bash
-xxd -l 16 -p /dev/urandom
-```
-OR
-```bash
-python3 -c 'import os; print(os.urandom(16).hex())'
-```
-
-**1. Place your config to /etc/telemt.toml**
-
-Open nano
-```bash
-nano /etc/telemt.toml
-```
-paste your config from [Configuration](#configuration) section
-
-then Ctrl+X -> Y -> Enter to save
-
-**2. Create service on /etc/systemd/system/telemt.service**
-
-Open nano
-```bash
-nano /etc/systemd/system/telemt.service
-```
-paste this Systemd Module
-```bash
-[Unit]
-Description=Telemt
-After=network.target
-
-[Service]
-Type=simple
-WorkingDirectory=/bin
-ExecStart=/bin/telemt /etc/telemt.toml
-Restart=on-failure
-LimitNOFILE=65536
-
-[Install]
-WantedBy=multi-user.target
-```
-then Ctrl+X -> Y -> Enter to save
-
-**3.**  In Shell type `systemctl start telemt` - it must start with zero exit-code
-
-**4.** In Shell type `systemctl status telemt` - there you can reach info about current MTProxy status
-
-**5.** In Shell type `systemctl enable telemt` - then telemt will start with system startup, after the network is up
-
-## Configuration
-### Minimal Configuration for First Start
-```toml
-# === General Settings ===
-[general]
-fast_mode = true
-use_middle_proxy = true
-# ad_tag = "00000000000000000000000000000000"
-# Path to proxy-secret binary (auto-downloaded if missing).
-proxy_secret_path = "proxy-secret"
-# disable_colors = false  # Disable colored output in logs (useful for files/systemd)
-
-# === Log Level ===
-# Log level: debug | verbose | normal | silent
-# Can be overridden with --silent or --log-level CLI flags
-# RUST_LOG env var takes absolute priority over all of these
-log_level = "normal"
-
-# === Middle Proxy - ME ===
-# Public IP override for ME KDF when behind NAT; leave unset to auto-detect.
-# middle_proxy_nat_ip = "203.0.113.10"
-# Enable STUN probing to discover public IP:port for ME.
-middle_proxy_nat_probe = true
-# Primary STUN server (host:port); defaults to Telegram STUN when empty.
-middle_proxy_nat_stun = "stun.l.google.com:19302"
-# Optional fallback STUN servers list.
-middle_proxy_nat_stun_servers = ["stun1.l.google.com:19302", "stun2.l.google.com:19302"]
-# Desired number of concurrent ME writers in pool.
-middle_proxy_pool_size = 16
-# Pre-initialized warm-standby ME connections kept idle.
-middle_proxy_warm_standby = 8
-# Ignore STUN/interface mismatch and keep ME enabled even if IP differs.
-stun_iface_mismatch_ignore = false
-# Keepalive padding frames - fl==4
-me_keepalive_enabled = true
-me_keepalive_interval_secs = 25           # Period between keepalives
-me_keepalive_jitter_secs = 5              # Jitter added to interval
-me_keepalive_payload_random = true        # Randomize 4-byte payload (vs zeros)
-# Stagger extra ME connections on warmup to de-phase lifecycles.
-me_warmup_stagger_enabled = true
-me_warmup_step_delay_ms = 500             # Base delay between extra connects
-me_warmup_step_jitter_ms = 300            # Jitter for warmup delay
-# Reconnect policy knobs.
-me_reconnect_max_concurrent_per_dc = 1    # Parallel reconnects per DC - EXPERIMENTAL! UNSTABLE!
-me_reconnect_backoff_base_ms = 500        # Backoff start
-me_reconnect_backoff_cap_ms = 30000       # Backoff cap
-me_reconnect_fast_retry_count = 11        # Quick retries before backoff
-
-[general.modes]
-classic = false
-secure = false
-tls = true
-
-[general.links]
-show = "*"
-# show = ["alice", "bob"] # Only show links for alice and bob
-# show = "*"              # Show links for all users
-# public_host = "proxy.example.com"  # Host (IP or domain) for tg:// links
-# public_port = 443                  # Port for tg:// links (default: server.port)
-
-# === Network Parameters ===
-[network]
-# Enable/disable families: true/false/auto(None)
-ipv4 = true
-ipv6 = false # UNSTABLE WITH ME
-# prefer = 4 or 6
-prefer = 4
-multipath = false # EXPERIMENTAL!
-
-# === Server Binding ===
-[server]
-port = 443
-listen_addr_ipv4 = "0.0.0.0"
-listen_addr_ipv6 = "::"
-# listen_unix_sock = "/var/run/telemt.sock" # Unix socket
-# listen_unix_sock_perm = "0666" # Socket file permissions
-# metrics_port = 9090
-# metrics_whitelist = [
-#    "192.168.0.0/24",
-#    "172.16.0.0/12",
-#    "127.0.0.1/32",
-#    "::1/128"
-#]
-
-# Listen on multiple interfaces/IPs - IPv4
-[[server.listeners]]
-ip = "0.0.0.0"
-
-# Listen on multiple interfaces/IPs - IPv6
-[[server.listeners]]
-ip = "::"
-
-# === Timeouts (in seconds) ===
-[timeouts]
-client_handshake = 30
-tg_connect = 10
-client_keepalive = 60
-client_ack = 300
-# Quick ME reconnects for single-address DCs (count and per-attempt timeout, ms).
-me_one_retry = 12
-me_one_timeout_ms = 1200
-
-# === Anti-Censorship & Masking ===
-[censorship]
-tls_domain = "petrovich.ru"
-mask = true
-mask_port = 443
-# mask_host = "petrovich.ru" # Defaults to tls_domain if not set
-# mask_unix_sock = "/var/run/nginx.sock" # Unix socket (mutually exclusive with mask_host)
-fake_cert_len = 2048
-
-# === Access Control & Users ===
-[access]
-replay_check_len = 65536
-replay_window_secs = 1800
-ignore_time_skew = false
-
-[access.users]
-# format: "username" = "32_hex_chars_secret"
-hello = "00000000000000000000000000000000"
-
-# [access.user_max_tcp_conns]
-# hello = 50
-
-# [access.user_max_unique_ips]
-# hello = 5
-
-# [access.user_data_quota]
-# hello = 1073741824 # 1 GB
-
-# === Upstreams & Routing ===
-[[upstreams]]
-type = "direct"
-enabled = true
-weight = 10
-
-# [[upstreams]]
-# type = "socks5"
-# address = "127.0.0.1:1080"
-# enabled = false
-# weight = 1
-
-# === DC Address Overrides ===
-# [dc_overrides]
-# "203" = "91.105.192.100:443"
-
-```
-### Advanced
-#### Adtag
-To use channel advertising and usage statistics from Telegram, get Adtag from [@mtproxybot](https://t.me/mtproxybot), add this parameter to section `[General]`
-```toml
-ad_tag = "00000000000000000000000000000000" # Replace zeros to your adtag from @mtproxybot
-```
-#### Listening and Announce IPs
-To specify listening address and/or address in links, add to section `[[server.listeners]]` of config.toml:
-```toml
-[[server.listeners]]
-ip = "0.0.0.0"          # 0.0.0.0 = all IPs; your IP = specific listening
-announce_ip = "1.2.3.4" # IP in links; comment with # if not used
-```
-#### Upstream Manager
-To specify upstream, add to section `[[upstreams]]` of config.toml:
-##### Bind on IP
-```toml
-[[upstreams]]
-type = "direct"
-weight = 1
-enabled = true
-interface = "192.168.1.100" # Change to your outgoing IP
-```
-##### SOCKS4/5 as Upstream
-- Without Auth:
-```toml
-[[upstreams]]
-type = "socks5"            # Specify SOCKS4 or SOCKS5
-address = "1.2.3.4:1234"   # SOCKS-server Address
-weight = 1                 # Set Weight for Scenarios
-enabled = true
-```
-
-- With Auth:
-```toml
-[[upstreams]]
-type = "socks5"            # Specify SOCKS4 or SOCKS5
-address = "1.2.3.4:1234"   # SOCKS-server Address
-username = "user"          # Username for Auth on SOCKS-server
-password = "pass"          # Password for Auth on SOCKS-server
-weight = 1                 # Set Weight for Scenarios
-enabled = true
-```
+- [Quick Start Guide RU](docs/QUICK_START_GUIDE.ru.md)
+- [Quick Start Guide EN](docs/QUICK_START_GUIDE.en.md)
 
 ## FAQ
+
+- [FAQ RU](docs/FAQ.ru.md)
+- [FAQ EN](docs/FAQ.en.md)
+
 ### Recognizability for DPI and crawler
 Since version 1.1.0.0, we have debugged masking perfectly: for all clients without "presenting" a key, 
 we transparently direct traffic to the target host!
@@ -509,41 +281,6 @@ chmod +x /bin/telemt
 telemt config.toml
 ```
 
-## Docker
-**Quick start (Docker Compose)**
-
-1. Edit `config.toml` in repo root (at least: port, users secrets, tls_domain)
-2. Start container:
-```bash
-docker compose up -d --build
-```
-3. Check logs:
-```bash
-docker compose logs -f telemt
-```
-4. Stop:
-```bash
-docker compose down
-```
-
-**Notes**
-- `docker-compose.yml` maps `./config.toml` to `/app/config.toml` (read-only)
-- By default it publishes `443:443` and runs with dropped capabilities (only `NET_BIND_SERVICE` is added)
-- If you really need host networking (usually only for some IPv6 setups) uncomment `network_mode: host`
-
-**Run without Compose**
-```bash
-docker build -t telemt:local .
-docker run --name telemt --restart unless-stopped \
-  -p 443:443 \
-  -e RUST_LOG=info \
-  -v "$PWD/config.toml:/app/config.toml:ro" \
-  --read-only \
-  --cap-drop ALL --cap-add NET_BIND_SERVICE \
-  --ulimit nofile=65536:65536 \
-  telemt:local
-```
-
 ## Why Rust?
 - Long-running reliability and idempotent behavior
 - Rust's deterministic resource management - RAII 

config.full.toml

@@ -0,0 +1,697 @@
+# ==============================================================================
+#
+#   TELEMT — Advanced Rust-based Telegram MTProto Proxy
+#   Full Configuration Reference
+#
+#   This file is both a working config and a complete documentation.
+#   Every parameter is explained. Read it top to bottom before deploying.
+#
+#   Quick Start:
+#     1. Set [server].port to your desired port (443 recommended)
+#     2. Generate a secret: openssl rand -hex 16
+#     3. Put it in [access.users] under a name you choose
+#     4. Set [censorship].tls_domain to a popular unblocked HTTPS site
+#     5. Set your public IP in [general].middle_proxy_nat_ip
+#        and [general.links].public_host
+#     6. Set announce IP in [[server.listeners]]
+#     7. Run Telemt. It prints a tg:// link. Send it to your users.
+#
+#   Modes of Operation:
+#     Direct Mode  (use_middle_proxy = false)
+#       Connects straight to Telegram DCs via TCP. Simple, fast, low overhead.
+#       No ad_tag support. No CDN DC support (203, etc).
+#
+#     Middle-Proxy Mode  (use_middle_proxy = true)
+#       Connects to Telegram Middle-End servers via RPC protocol.
+#       Required for ad_tag monetization and CDN support.
+#       Requires proxy_secret_path and a valid public IP.
+#
+# ==============================================================================
+
+
+# ==============================================================================
+# LEGACY TOP-LEVEL FIELDS
+# ==============================================================================
+
+# Deprecated. Use [general.links].show instead.
+# Accepts "*" for all users, or an array like ["alice", "bob"].
+show_link = ["0"]
+
+# Fallback Datacenter index (1-5) when a client requests an unknown DC ID.
+# DC 2 is Amsterdam (Europe), closest for most CIS users.
+# default_dc = 2
+
+
+# ==============================================================================
+# GENERAL SETTINGS
+# ==============================================================================
+
+[general]
+
+# ------------------------------------------------------------------------------
+# Core Protocol
+# ------------------------------------------------------------------------------
+
+# Coalesce the MTProto handshake and first data payload into a single TCP packet.
+# Significantly reduces connection latency. No reason to disable.
+fast_mode = true
+
+# How the proxy connects to Telegram servers.
+# false = Direct TCP to Telegram DCs (simple, low overhead)
+# true  = Middle-End RPC protocol (required for ad_tag and CDN DCs)
+use_middle_proxy = true
+
+# 32-char hex Ad-Tag from @MTProxybot for sponsored channel injection.
+# Only works when use_middle_proxy = true.
+# Obtain yours: message @MTProxybot on Telegram, register your proxy.
+# ad_tag = "00000000000000000000000000000000"
+
+# ------------------------------------------------------------------------------
+# Middle-End Authentication
+# ------------------------------------------------------------------------------
+
+# Path to the Telegram infrastructure AES key file.
+# Auto-downloaded from https://core.telegram.org/getProxySecret on first run.
+# This key authenticates your proxy with Middle-End servers.
+proxy_secret_path = "proxy-secret"
+
+# ------------------------------------------------------------------------------
+# Public IP Configuration (Critical for Middle-Proxy Mode)
+# ------------------------------------------------------------------------------
+
+# Your server's PUBLIC IPv4 address.
+# Middle-End servers need this for the cryptographic Key Derivation Function.
+# If your server has a direct public IP, set it here.
+# If behind NAT (AWS, Docker, etc.), this MUST be your external IP.
+# If omitted, Telemt uses STUN to auto-detect (see middle_proxy_nat_probe).
+# middle_proxy_nat_ip = "203.0.113.10"
+
+# Auto-detect public IP via STUN servers defined in [network].
+# Set to false if you hardcoded middle_proxy_nat_ip above.
+# Set to true if you want automatic detection.
+middle_proxy_nat_probe = true
+
+# ------------------------------------------------------------------------------
+# Middle-End Connection Pool
+# ------------------------------------------------------------------------------
+
+# Number of persistent multiplexed RPC connections to ME servers.
+# All client traffic is routed through these "fat pipes".
+# 8 handles thousands of concurrent users comfortably.
+middle_proxy_pool_size = 8
+
+# Legacy field. Connections kept initialized but idle as warm standby.
+middle_proxy_warm_standby = 16
+
+# ------------------------------------------------------------------------------
+# Middle-End Keepalive
+# Telegram ME servers aggressively kill idle TCP connections.
+# These settings send periodic RPC_PING frames to keep pipes alive.
+# ------------------------------------------------------------------------------
+
+me_keepalive_enabled = true
+
+# Base interval between pings in seconds.
+me_keepalive_interval_secs = 25
+
+# Random jitter added to interval to prevent all connections pinging simultaneously.
+me_keepalive_jitter_secs = 5
+
+# Randomize ping payload bytes to prevent DPI from fingerprinting ping patterns.
+me_keepalive_payload_random = true
+
+# ------------------------------------------------------------------------------
+# Client-Side Limits
+# ------------------------------------------------------------------------------
+
+# Max buffered ciphertext per client (bytes) when upstream is slow.
+# Acts as backpressure to prevent memory exhaustion. 256KB is safe.
+crypto_pending_buffer = 262144
+
+# Maximum single MTProto frame size from client. 16MB is protocol standard.
+max_client_frame = 16777216
+
+# ------------------------------------------------------------------------------
+# Crypto Desynchronization Logging
+# Desync errors usually mean DPI/GFW is tampering with connections.
+# ------------------------------------------------------------------------------
+
+# true  = full forensics (trace ID, IP hash, hex dumps) for EVERY desync event
+# false = deduplicated logging, one entry per time window (prevents log spam)
+# Set true if you are actively debugging DPI interference.
+desync_all_full = true
+
+# ------------------------------------------------------------------------------
+# Beobachten — Built-in Honeypot / Active Probe Tracker
+# Tracks IPs that fail handshakes or behave like TLS scanners.
+# Output file can be fed into fail2ban or iptables for auto-blocking.
+# ------------------------------------------------------------------------------
+
+beobachten = true
+
+# How long (minutes) to remember a suspicious IP before expiring it.
+beobachten_minutes = 30
+
+# How often (seconds) to flush tracker state to disk.
+beobachten_flush_secs = 15
+
+# File path for the tracker output.
+beobachten_file = "cache/beobachten.txt"
+
+# ------------------------------------------------------------------------------
+# Hardswap — Zero-Downtime ME Pool Rotation
+# When Telegram updates ME server IPs, Hardswap creates a completely new pool,
+# waits until it is fully ready, migrates traffic, then kills the old pool.
+# Users experience zero interruption.
+# ------------------------------------------------------------------------------
+
+hardswap = true
+
+# ------------------------------------------------------------------------------
+# ME Pool Warmup Staggering
+# When creating a new pool, connections are opened one by one with delays
+# to avoid a burst of SYN packets that could trigger ISP flood protection.
+# ------------------------------------------------------------------------------
+
+me_warmup_stagger_enabled = true
+
+# Delay between each connection creation (milliseconds).
+me_warmup_step_delay_ms = 500
+
+# Random jitter added to the delay (milliseconds).
+me_warmup_step_jitter_ms = 300
+
+# ------------------------------------------------------------------------------
+# ME Reconnect Backoff
+# If an ME server drops the connection, Telemt retries with this strategy.
+# ------------------------------------------------------------------------------
+
+# Max simultaneous reconnect attempts per DC.
+me_reconnect_max_concurrent_per_dc = 8
+
+# Exponential backoff base (milliseconds).
+me_reconnect_backoff_base_ms = 500
+
+# Backoff ceiling (milliseconds). Will never wait longer than this.
+me_reconnect_backoff_cap_ms = 30000
+
+# Number of instant retries before switching to exponential backoff.
+me_reconnect_fast_retry_count = 12
+
+# ------------------------------------------------------------------------------
+# NAT Mismatch Behavior
+# If STUN-detected IP differs from local interface IP (you are behind NAT).
+# false = abort ME mode (safe default)
+# true  = force ME mode anyway (use if you know your NAT setup is correct)
+# ------------------------------------------------------------------------------
+
+stun_iface_mismatch_ignore = false
+
+# ------------------------------------------------------------------------------
+# Logging
+# ------------------------------------------------------------------------------
+
+# File to log unknown DC requests (DC IDs outside standard 1-5).
+unknown_dc_log_path = "unknown-dc.txt"
+
+# Verbosity: "debug" | "verbose" | "normal" | "silent"
+log_level = "normal"
+
+# Disable ANSI color codes in log output (useful for file logging).
+disable_colors = false
+
+# ------------------------------------------------------------------------------
+# FakeTLS Record Sizing
+# Buffer small MTProto packets into larger TLS records to mimic real HTTPS.
+# Real HTTPS servers send records close to MTU size (~1400 bytes).
+# A stream of tiny TLS records is a strong DPI signal.
+# Set to 0 to disable. Set to 1400 for realistic HTTPS emulation.
+# ------------------------------------------------------------------------------
+
+fast_mode_min_tls_record = 1400
+
+# ------------------------------------------------------------------------------
+# Periodic Updates
+# ------------------------------------------------------------------------------
+
+# How often (seconds) to re-fetch ME server lists and proxy secrets
+# from core.telegram.org. Keeps your proxy in sync with Telegram infrastructure.
+update_every = 300
+
+# How often (seconds) to force a Hardswap even if the ME map is unchanged.
+# Shorter intervals mean shorter-lived TCP flows, harder for DPI to profile.
+me_reinit_every_secs = 600
+
+# ------------------------------------------------------------------------------
+# Hardswap Warmup Tuning
+# Fine-grained control over how the new pool is warmed up before traffic switch.
+# ------------------------------------------------------------------------------
+
+me_hardswap_warmup_delay_min_ms = 1000
+me_hardswap_warmup_delay_max_ms = 2000
+me_hardswap_warmup_extra_passes = 3
+me_hardswap_warmup_pass_backoff_base_ms = 500
+
+# ------------------------------------------------------------------------------
+# Config Update Debouncing
+# Telegram sometimes pushes transient/broken configs. Debouncing requires
+# N consecutive identical fetches before applying a change.
+# ------------------------------------------------------------------------------
+
+# ME server list must be identical for this many fetches before applying.
+me_config_stable_snapshots = 2
+
+# Minimum seconds between config applications.
+me_config_apply_cooldown_secs = 300
+
+# Proxy secret must be identical for this many fetches before applying.
+proxy_secret_stable_snapshots = 2
+
+# ------------------------------------------------------------------------------
+# Proxy Secret Rotation
+# ------------------------------------------------------------------------------
+
+# Apply newly downloaded secrets at runtime without restart.
+proxy_secret_rotate_runtime = true
+
+# Maximum acceptable secret length (bytes). Rejects abnormally large secrets.
+proxy_secret_len_max = 256
+
+# ------------------------------------------------------------------------------
+# Hardswap Drain Settings
+# Controls graceful shutdown of old ME connections during pool rotation.
+# ------------------------------------------------------------------------------
+
+# Seconds to keep old connections alive for in-flight data before force-closing.
+me_pool_drain_ttl_secs = 90
+
+# Minimum ratio of healthy connections in new pool before draining old pool.
+# 0.8 = at least 80% of new pool must be ready.
+me_pool_min_fresh_ratio = 0.8
+
+# Maximum seconds to wait for drain to complete before force-killing.
+me_reinit_drain_timeout_secs = 120
+
+# ------------------------------------------------------------------------------
+# NTP Clock Check
+# MTProto uses timestamps. Clock drift > 30 seconds breaks handshakes.
+# Telemt checks on startup and warns if out of sync.
+# ------------------------------------------------------------------------------
+
+ntp_check = true
+ntp_servers = ["pool.ntp.org"]
+
+# ------------------------------------------------------------------------------
+# Auto-Degradation
+# If ME servers become completely unreachable (ISP blocking),
+# automatically fall back to Direct Mode so users stay connected.
+# ------------------------------------------------------------------------------
+
+auto_degradation_enabled = true
+
+# Number of DC groups that must be unreachable before triggering fallback.
+degradation_min_unavailable_dc_groups = 2
+
+
+# ==============================================================================
+# ALLOWED CLIENT PROTOCOLS
+# Only enable what you need. In censored regions, TLS-only is safest.
+# ==============================================================================
+
+[general.modes]
+
+# Classic MTProto. Unobfuscated length prefixes. Trivially detected by DPI.
+# No reason to enable unless you have ancient clients.
+classic = false
+
+# Obfuscated MTProto with randomized padding. Better than classic, but
+# still detectable by statistical analysis of packet sizes.
+secure = false
+
+# FakeTLS (ee-secrets). Wraps MTProto in TLS 1.3 framing.
+# To DPI, it looks like a normal HTTPS connection.
+# This should be the ONLY enabled mode in censored environments.
+tls = true
+
+
+# ==============================================================================
+# STARTUP LINK GENERATION
+# Controls what tg:// invite links are printed to console on startup.
+# ==============================================================================
+
+[general.links]
+
+# Which users to generate links for.
+# "*" = all users, or an array like ["alice", "bob"].
+show = "*"
+
+# IP or domain to embed in the tg:// link.
+# If omitted, Telemt uses STUN to auto-detect.
+# Set this to your server's public IP or domain for reliable links.
+# public_host = "proxy.example.com"
+
+# Port to embed in the tg:// link.
+# If omitted, uses [server].port.
+# public_port = 443
+
+
+# ==============================================================================
+# NETWORK & IP RESOLUTION
+# ==============================================================================
+
+[network]
+
+# Enable IPv4 for outbound connections to Telegram.
+ipv4 = true
+
+# Enable IPv6 for outbound connections to Telegram.
+ipv6 = false
+
+# Prefer IPv4 (4) or IPv6 (6) when both are available.
+prefer = 4
+
+# Experimental: use both IPv4 and IPv6 ME servers simultaneously.
+# May improve reliability but doubles connection count.
+multipath = false
+
+# STUN servers for external IP discovery.
+# Used for Middle-Proxy KDF (if nat_probe=true) and link generation.
+stun_servers = [
+    "stun.l.google.com:5349",
+    "stun1.l.google.com:3478",
+    "stun.gmx.net:3478",
+    "stun.l.google.com:19302"
+]
+
+# If UDP STUN is blocked, attempt TCP-based STUN as fallback.
+stun_tcp_fallback = true
+
+# If all STUN fails, use HTTP APIs to discover public IP.
+http_ip_detect_urls = [
+    "https://ifconfig.me/ip",
+    "https://api.ipify.org"
+]
+
+# Cache discovered public IP to this file to survive restarts.
+cache_public_ip_path = "cache/public_ip.txt"
+
+
+# ==============================================================================
+# SERVER BINDING & METRICS
+# ==============================================================================
+
+[server]
+
+# TCP port to listen on.
+# 443 is recommended (looks like normal HTTPS traffic).
+port = 443
+
+# IPv4 bind address. "0.0.0.0" = all interfaces.
+listen_addr_ipv4 = "0.0.0.0"
+
+# IPv6 bind address. "::" = all interfaces.
+listen_addr_ipv6 = "::"
+
+# Unix socket listener (for reverse proxy setups with Nginx/HAProxy).
+# listen_unix_sock = "/var/run/telemt.sock"
+# listen_unix_sock_perm = "0660"
+
+# Enable PROXY protocol header parsing.
+# Set true ONLY if Telemt is behind HAProxy/Nginx that injects PROXY headers.
+# If enabled without a proxy in front, clients will fail to connect.
+proxy_protocol = false
+
+# Prometheus metrics HTTP endpoint port.
+# Uncomment to enable. Access at http://your-server:9090/metrics
+# metrics_port = 9090
+
+# IP ranges allowed to access the metrics endpoint.
+metrics_whitelist = [
+    "127.0.0.1/32",
+    "::1/128"
+]
+
+# ------------------------------------------------------------------------------
+# Listener Overrides
+# Define explicit listeners with specific bind IPs and announce IPs.
+# The announce IP is what gets embedded in tg:// links and sent to ME servers.
+# You MUST set announce to your server's public IP for ME mode to work.
+# ------------------------------------------------------------------------------
+
+# [[server.listeners]]
+# ip = "0.0.0.0"
+# announce = "203.0.113.10"
+# reuse_allow = false
+
+
+# ==============================================================================
+# TIMEOUTS (seconds unless noted)
+# ==============================================================================
+
+[timeouts]
+
+# Maximum time for client to complete FakeTLS + MTProto handshake.
+client_handshake = 15
+
+# Maximum time to establish TCP connection to upstream Telegram DC.
+tg_connect = 10
+
+# TCP keepalive interval for client connections.
+client_keepalive = 60
+
+# Maximum client inactivity before dropping the connection.
+client_ack = 300
+
+# Instant retry count for a single ME endpoint before giving up on it.
+me_one_retry = 3
+
+# Timeout (milliseconds) for a single ME endpoint connection attempt.
+me_one_timeout_ms = 1500
+
+
+# ==============================================================================
+# ANTI-CENSORSHIP / FAKETLS / MASKING
+# This is where Telemt becomes invisible to Deep Packet Inspection.
+# ==============================================================================
+
+[censorship]
+
+# ------------------------------------------------------------------------------
+# TLS Domain Fronting
+# The SNI (Server Name Indication) your proxy presents to connecting clients.
+# Must be a popular, unblocked HTTPS website in your target country.
+# DPI sees traffic to this domain. Choose carefully.
+# Good choices: major CDNs, banks, government sites, search engines.
+# Bad choices: obscure sites, already-blocked domains.
+# ------------------------------------------------------------------------------
+
+tls_domain = "www.google.com"
+
+# ------------------------------------------------------------------------------
+# Active Probe Masking
+# When someone connects but fails the MTProto handshake (wrong secret),
+# they might be an ISP active prober testing if this is a proxy.
+#
+# mask = false: drop the connection (prober knows something is here)
+# mask = true:  transparently proxy them to mask_host (prober sees a real website)
+#
+# With mask enabled, your server is indistinguishable from a real web server
+# to anyone who doesn't have the correct secret.
+# ------------------------------------------------------------------------------
+
+mask = true
+
+# The real web server to forward failed handshakes to.
+# If omitted, defaults to tls_domain.
+# mask_host = "www.google.com"
+
+# Port on the mask host to connect to.
+mask_port = 443
+
+# Inject PROXY protocol header when forwarding to mask host.
+# 0 = disabled, 1 = v1, 2 = v2. Leave disabled unless mask_host expects it.
+# mask_proxy_protocol = 0
+
+# ------------------------------------------------------------------------------
+# TLS Certificate Emulation
+# ------------------------------------------------------------------------------
+
+# Size (bytes) of the locally generated fake TLS certificate.
+# Only used when tls_emulation is disabled.
+fake_cert_len = 2048
+
+# KILLER FEATURE: Real-Time TLS Emulation.
+# Telemt connects to tls_domain, fetches its actual TLS 1.3 certificate chain,
+# and exactly replicates the byte sizes of ServerHello and Certificate records.
+# Defeats DPI that uses TLS record length heuristics to detect proxies.
+# Strongly recommended in censored environments.
+tls_emulation = true
+
+# Directory to cache fetched TLS certificates.
+tls_front_dir = "tlsfront"
+
+# ------------------------------------------------------------------------------
+# ServerHello Timing
+# Real web servers take 30-150ms to respond to ClientHello due to network
+# latency and crypto processing. A proxy responding in <1ms is suspicious.
+# These settings add realistic delay to mimic genuine server behavior.
+# ------------------------------------------------------------------------------
+
+# Minimum delay before sending ServerHello (milliseconds).
+server_hello_delay_min_ms = 50
+
+# Maximum delay before sending ServerHello (milliseconds).
+server_hello_delay_max_ms = 150
+
+# ------------------------------------------------------------------------------
+# TLS Session Tickets
+# Real TLS 1.3 servers send 1-2 NewSessionTicket messages after handshake.
+# A server that sends zero tickets is anomalous and may trigger DPI flags.
+# Set this to match your tls_domain's behavior (usually 2).
+# ------------------------------------------------------------------------------
+
+# tls_new_session_tickets = 0
+
+# ------------------------------------------------------------------------------
+# Full Certificate Frequency
+# When tls_emulation is enabled, this controls how often (per client IP)
+# to send the complete emulated certificate chain.
+#
+# > 0: Subsequent connections within TTL seconds get a smaller cached version.
+#       Saves bandwidth but creates a detectable size difference between
+#       first and repeat connections.
+#
+# = 0: Every connection gets the full certificate. More bandwidth but
+#       perfectly consistent behavior, no anomalies for DPI to detect.
+# ------------------------------------------------------------------------------
+
+tls_full_cert_ttl_secs = 0
+
+# ------------------------------------------------------------------------------
+# ALPN Enforcement
+# Ensure ServerHello responds with the exact ALPN protocol the client requested.
+# Mismatched ALPN (e.g., client asks h2, server says http/1.1) is a DPI red flag.
+# ------------------------------------------------------------------------------
+
+alpn_enforce = true
+
+
+# ==============================================================================
+# ACCESS CONTROL & USERS
+# ==============================================================================
+
+[access]
+
+# ------------------------------------------------------------------------------
+# Replay Attack Protection
+# DPI can record a legitimate user's handshake and replay it later to probe
+# whether the server is a proxy. Telemt remembers recent handshake nonces
+# and rejects duplicates.
+# ------------------------------------------------------------------------------
+
+# Number of nonce slots in the replay detection buffer.
+replay_check_len = 65536
+
+# How long (seconds) to remember nonces before expiring them.
+replay_window_secs = 1800
+
+# Allow clients with incorrect system clocks to connect.
+# false = reject clients with significant time skew (more secure)
+# true  = accept anyone regardless of clock (more permissive)
+ignore_time_skew = false
+
+# ------------------------------------------------------------------------------
+# User Secrets
+# Each user needs a unique 32-character hex string as their secret.
+# Generate with: openssl rand -hex 16
+#
+# This secret is embedded in the tg:// link. Anyone with it can connect.
+# Format: username = "hex_secret"
+# ------------------------------------------------------------------------------
+
+[access.users]
+# alice = "0123456789abcdef0123456789abcdef"
+# bob = "fedcba9876543210fedcba9876543210"
+
+# ------------------------------------------------------------------------------
+# Per-User Connection Limits
+# Limits concurrent TCP connections per user to prevent secret sharing.
+# Uncomment and set for each user as needed.
+# ------------------------------------------------------------------------------
+
+[access.user_max_tcp_conns]
+# alice = 100
+# bob = 50
+
+# ------------------------------------------------------------------------------
+# Per-User Expiration Dates
+# Automatically revoke access after the specified date (ISO 8601 format).
+# ------------------------------------------------------------------------------
+
+[access.user_expirations]
+# alice = "2025-12-31T23:59:59Z"
+# bob = "2026-06-15T00:00:00Z"
+
+# ------------------------------------------------------------------------------
+# Per-User Data Quotas
+# Maximum total bytes transferred per user. Connection refused after limit.
+# ------------------------------------------------------------------------------
+
+[access.user_data_quota]
+# alice = 107374182400
+# bob = 53687091200
+
+# ------------------------------------------------------------------------------
+# Per-User Unique IP Limits
+# Maximum number of different IP addresses that can use this secret
+# at the same time. Highly effective against secret leaking/sharing.
+# Set to 1 for single-device, 2-3 for phone+desktop, etc.
+# ------------------------------------------------------------------------------
+
+[access.user_max_unique_ips]
+# alice = 3
+# bob = 2
+
+
+# ==============================================================================
+# UPSTREAM ROUTING
+# Controls how Telemt connects to Telegram servers (or ME servers).
+# If omitted entirely, uses the OS default route.
+# ==============================================================================
+
+# ------------------------------------------------------------------------------
+# Direct upstream: use the server's own network interface.
+# You can optionally bind to a specific interface or local IP.
+# ------------------------------------------------------------------------------
+
+# [[upstreams]]
+# type = "direct"
+# interface = "eth0"
+# bind_addresses = ["192.0.2.10"]
+# weight = 1
+# enabled = true
+# scopes = "*"
+
+# ------------------------------------------------------------------------------
+# SOCKS5 upstream: route Telegram traffic through a SOCKS5 proxy.
+# Useful if your server's IP is blocked from reaching Telegram DCs.
+# ------------------------------------------------------------------------------
+
+# [[upstreams]]
+# type = "socks5"
+# address = "198.51.100.30:1080"
+# username = "proxy-user"
+# password = "proxy-pass"
+# weight = 1
+# enabled = true
+
+
+# ==============================================================================
+# DATACENTER OVERRIDES
+# Force specific DC IDs to route to specific IP:Port combinations.
+# DC 203 (CDN) is auto-injected by Telemt if not specified here.
+# ==============================================================================
+
+# [dc_overrides]
+# "201" = "149.154.175.50:443"
+# "202" = ["149.154.167.51:443", "149.154.175.100:443"]

config.toml

@@ -1,11 +1,13 @@
+### Telemt Based Config.toml
+# We believe that these settings are sufficient for most scenarios 
+# where cutting-egde methods and parameters or special solutions are not needed
+
 # === General Settings ===
 [general]
-fast_mode = true
-use_middle_proxy = true
+use_middle_proxy = false
+# Global ad_tag fallback when user has no per-user tag in [access.user_ad_tags]
 # ad_tag = "00000000000000000000000000000000"
-# Path to proxy-secret binary (auto-downloaded if missing).
-proxy_secret_path = "proxy-secret"
-# disable_colors = false  # Disable colored output in logs (useful for files/systemd)
+# Per-user ad_tag in [access.user_ad_tags] (32 hex from @MTProxybot)
 
 # === Log Level ===
 # Log level: debug | verbose | normal | silent
@@ -13,36 +15,6 @@ proxy_secret_path = "proxy-secret"
 # RUST_LOG env var takes absolute priority over all of these
 log_level = "normal"
 
-# === Middle Proxy - ME ===
-# Public IP override for ME KDF when behind NAT; leave unset to auto-detect.
-# middle_proxy_nat_ip = "203.0.113.10"
-# Enable STUN probing to discover public IP:port for ME.
-middle_proxy_nat_probe = true
-# Primary STUN server (host:port); defaults to Telegram STUN when empty.
-middle_proxy_nat_stun = "stun.l.google.com:19302"
-# Optional fallback STUN servers list.
-middle_proxy_nat_stun_servers = ["stun1.l.google.com:19302", "stun2.l.google.com:19302"]
-# Desired number of concurrent ME writers in pool.
-middle_proxy_pool_size = 16
-# Pre-initialized warm-standby ME connections kept idle.
-middle_proxy_warm_standby = 8
-# Ignore STUN/interface mismatch and keep ME enabled even if IP differs.
-stun_iface_mismatch_ignore = false
-# Keepalive padding frames - fl==4
-me_keepalive_enabled = true
-me_keepalive_interval_secs = 25           # Period between keepalives
-me_keepalive_jitter_secs = 5              # Jitter added to interval
-me_keepalive_payload_random = true        # Randomize 4-byte payload (vs zeros)
-# Stagger extra ME connections on warmup to de-phase lifecycles.
-me_warmup_stagger_enabled = true
-me_warmup_step_delay_ms = 500             # Base delay between extra connects
-me_warmup_step_jitter_ms = 300            # Jitter for warmup delay
-# Reconnect policy knobs.
-me_reconnect_max_concurrent_per_dc = 1    # Parallel reconnects per DC - EXPERIMENTAL! UNSTABLE!
-me_reconnect_backoff_base_ms = 500        # Backoff start
-me_reconnect_backoff_cap_ms = 30000       # Backoff cap
-me_reconnect_fast_retry_count = 11        # Quick retries before backoff
-
 [general.modes]
 classic = false
 secure = false
@@ -55,89 +27,31 @@ show = "*"
 # public_host = "proxy.example.com"  # Host (IP or domain) for tg:// links
 # public_port = 443                  # Port for tg:// links (default: server.port)
 
-# === Network Parameters ===
-[network]
-# Enable/disable families: true/false/auto(None)
-ipv4 = true
-ipv6 = false # UNSTABLE WITH ME
-# prefer = 4 or 6
-prefer = 4
-multipath = false # EXPERIMENTAL!
-
 # === Server Binding ===
 [server]
 port = 443
-listen_addr_ipv4 = "0.0.0.0"
-listen_addr_ipv6 = "::"
-# listen_unix_sock = "/var/run/telemt.sock" # Unix socket
-# listen_unix_sock_perm = "0666" # Socket file permissions
 # proxy_protocol = false           # Enable if behind HAProxy/nginx with PROXY protocol
 # metrics_port = 9090
-# metrics_whitelist = ["127.0.0.1", "::1"]
+# metrics_whitelist = ["127.0.0.1", "::1", "0.0.0.0/0"]
+
+[server.api]
+enabled = true
+listen = "0.0.0.0:9091"
+whitelist = ["127.0.0.0/8"]
+minimal_runtime_enabled = false
+minimal_runtime_cache_ttl_ms = 1000
 
 # Listen on multiple interfaces/IPs - IPv4
 [[server.listeners]]
 ip = "0.0.0.0"
 
-# Listen on multiple interfaces/IPs - IPv6
-[[server.listeners]]
-ip = "::"
-
-# === Timeouts (in seconds) ===
-[timeouts]
-client_handshake = 30
-tg_connect = 10
-client_keepalive = 60
-client_ack = 300
-# Quick ME reconnects for single-address DCs (count and per-attempt timeout, ms).
-me_one_retry = 12
-me_one_timeout_ms = 1200
-
 # === Anti-Censorship & Masking ===
 [censorship]
 tls_domain = "petrovich.ru"
-# tls_domains = ["example.com", "cdn.example.net"] # Additional domains for EE links
 mask = true
-mask_port = 443
-# mask_host = "petrovich.ru" # Defaults to tls_domain if not set
-# mask_unix_sock = "/var/run/nginx.sock" # Unix socket (mutually exclusive with mask_host)
-fake_cert_len = 2048
-# tls_emulation = false        # Fetch real cert lengths and emulate TLS records
-# tls_front_dir = "tlsfront"   # Cache directory for TLS emulation
-
-# === Access Control & Users ===
-[access]
-replay_check_len = 65536
-replay_window_secs = 1800
-ignore_time_skew = false
+tls_emulation = true        # Fetch real cert lengths and emulate TLS records
+tls_front_dir = "tlsfront"   # Cache directory for TLS emulation
 
 [access.users]
 # format: "username" = "32_hex_chars_secret"
 hello = "00000000000000000000000000000000"
-
-# [access.user_max_tcp_conns]
-# hello = 50
-
-# [access.user_max_unique_ips]
-# hello = 5
-
-# [access.user_data_quota]
-# hello = 1073741824 # 1 GB
-
-# === Upstreams & Routing ===
-[[upstreams]]
-type = "direct"
-enabled = true
-weight = 10
-# interface = "192.168.1.100"           # Bind outgoing to specific IP or iface name
-# bind_addresses = ["192.168.1.100"]    # List for round-robin binding (family must match target)
-
-# [[upstreams]]
-# type = "socks5"
-# address = "127.0.0.1:1080"
-# enabled = false
-# weight = 1
-
-# === DC Address Overrides ===
-# [dc_overrides]
-# "203" = "91.105.192.100:443"

docker-compose.yml

@@ -1,11 +1,12 @@
 services:
   telemt:
+    image: ghcr.io/telemt/telemt:latest
     build: .
     container_name: telemt
     restart: unless-stopped
     ports:
       - "443:443"
-      - "9090:9090"
+      - "127.0.0.1:9090:9090"
     # Allow caching 'proxy-secret' in read-only container
     working_dir: /run/telemt
     volumes:

docs/API.md

@@ -0,0 +1,673 @@
+# Telemt Control API
+
+## Purpose
+Control-plane HTTP API for runtime visibility and user/config management.
+Data-plane MTProto traffic is out of scope.
+
+## Runtime Configuration
+API runtime is configured in `[server.api]`.
+
+| Field | Type | Default | Description |
+| --- | --- | --- | --- |
+| `enabled` | `bool` | `false` | Enables REST API listener. |
+| `listen` | `string` (`IP:PORT`) | `127.0.0.1:9091` | API bind address. |
+| `whitelist` | `CIDR[]` | `127.0.0.1/32, ::1/128` | Source IP allowlist. Empty list means allow all. |
+| `auth_header` | `string` | `""` | Exact value for `Authorization` header. Empty disables header auth. |
+| `request_body_limit_bytes` | `usize` | `65536` | Maximum request body size. Must be `> 0`. |
+| `minimal_runtime_enabled` | `bool` | `false` | Enables runtime snapshot endpoints requiring ME pool read-lock aggregation. |
+| `minimal_runtime_cache_ttl_ms` | `u64` | `1000` | Cache TTL for minimal snapshots. `0` disables cache; valid range is `[0, 60000]`. |
+| `runtime_edge_enabled` | `bool` | `false` | Enables runtime edge endpoints with cached aggregation payloads. |
+| `runtime_edge_cache_ttl_ms` | `u64` | `1000` | Cache TTL for runtime edge summary payloads. `0` disables cache. |
+| `runtime_edge_top_n` | `usize` | `10` | Top-N rows for runtime edge leaderboard payloads. |
+| `runtime_edge_events_capacity` | `usize` | `256` | Ring-buffer size for `/v1/runtime/events/recent`. |
+| `read_only` | `bool` | `false` | Disables mutating endpoints. |
+
+`server.admin_api` is accepted as an alias for backward compatibility.
+
+Runtime validation for API config:
+- `server.api.listen` must be a valid `IP:PORT`.
+- `server.api.request_body_limit_bytes` must be `> 0`.
+- `server.api.minimal_runtime_cache_ttl_ms` must be within `[0, 60000]`.
+- `server.api.runtime_edge_cache_ttl_ms` must be within `[0, 60000]`.
+- `server.api.runtime_edge_top_n` must be within `[1, 1000]`.
+- `server.api.runtime_edge_events_capacity` must be within `[16, 4096]`.
+
+## Protocol Contract
+
+| Item | Value |
+| --- | --- |
+| Transport | HTTP/1.1 |
+| Content type | `application/json; charset=utf-8` |
+| Prefix | `/v1` |
+| Optimistic concurrency | `If-Match: <revision>` on mutating requests (optional) |
+| Revision format | SHA-256 hex of current `config.toml` content |
+
+### Success Envelope
+```json
+{
+  "ok": true,
+  "data": {},
+  "revision": "sha256-hex"
+}
+```
+
+### Error Envelope
+```json
+{
+  "ok": false,
+  "error": {
+    "code": "machine_code",
+    "message": "human-readable"
+  },
+  "request_id": 1
+}
+```
+
+## Request Processing Order
+
+Requests are processed in this order:
+1. `api_enabled` gate (`503 api_disabled` if disabled).
+2. Source IP whitelist gate (`403 forbidden`).
+3. `Authorization` header gate when configured (`401 unauthorized`).
+4. Route and method matching (`404 not_found` or `405 method_not_allowed`).
+5. `read_only` gate for mutating routes (`403 read_only`).
+6. Request body read/limit/JSON decode (`413 payload_too_large`, `400 bad_request`).
+7. Business validation and config write path.
+
+Notes:
+- Whitelist is evaluated against the direct TCP peer IP (`SocketAddr::ip`), without `X-Forwarded-For` support.
+- `Authorization` check is exact string equality against configured `auth_header`.
+
+## Endpoint Matrix
+
+| Method | Path | Body | Success | `data` contract |
+| --- | --- | --- | --- | --- |
+| `GET` | `/v1/health` | none | `200` | `HealthData` |
+| `GET` | `/v1/system/info` | none | `200` | `SystemInfoData` |
+| `GET` | `/v1/runtime/gates` | none | `200` | `RuntimeGatesData` |
+| `GET` | `/v1/limits/effective` | none | `200` | `EffectiveLimitsData` |
+| `GET` | `/v1/security/posture` | none | `200` | `SecurityPostureData` |
+| `GET` | `/v1/security/whitelist` | none | `200` | `SecurityWhitelistData` |
+| `GET` | `/v1/stats/summary` | none | `200` | `SummaryData` |
+| `GET` | `/v1/stats/zero/all` | none | `200` | `ZeroAllData` |
+| `GET` | `/v1/stats/upstreams` | none | `200` | `UpstreamsData` |
+| `GET` | `/v1/stats/minimal/all` | none | `200` | `MinimalAllData` |
+| `GET` | `/v1/stats/me-writers` | none | `200` | `MeWritersData` |
+| `GET` | `/v1/stats/dcs` | none | `200` | `DcStatusData` |
+| `GET` | `/v1/runtime/me_pool_state` | none | `200` | `RuntimeMePoolStateData` |
+| `GET` | `/v1/runtime/me_quality` | none | `200` | `RuntimeMeQualityData` |
+| `GET` | `/v1/runtime/upstream_quality` | none | `200` | `RuntimeUpstreamQualityData` |
+| `GET` | `/v1/runtime/nat_stun` | none | `200` | `RuntimeNatStunData` |
+| `GET` | `/v1/runtime/connections/summary` | none | `200` | `RuntimeEdgeConnectionsSummaryData` |
+| `GET` | `/v1/runtime/events/recent` | none | `200` | `RuntimeEdgeEventsData` |
+| `GET` | `/v1/stats/users` | none | `200` | `UserInfo[]` |
+| `GET` | `/v1/users` | none | `200` | `UserInfo[]` |
+| `POST` | `/v1/users` | `CreateUserRequest` | `201` | `CreateUserResponse` |
+| `GET` | `/v1/users/{username}` | none | `200` | `UserInfo` |
+| `PATCH` | `/v1/users/{username}` | `PatchUserRequest` | `200` | `UserInfo` |
+| `DELETE` | `/v1/users/{username}` | none | `200` | `string` (deleted username) |
+| `POST` | `/v1/users/{username}/rotate-secret` | `RotateSecretRequest` or empty body | `404` | `ErrorResponse` (`not_found`, current runtime behavior) |
+
+## Common Error Codes
+
+| HTTP | `error.code` | Trigger |
+| --- | --- | --- |
+| `400` | `bad_request` | Invalid JSON, validation failures, malformed request body. |
+| `401` | `unauthorized` | Missing/invalid `Authorization` when `auth_header` is configured. |
+| `403` | `forbidden` | Source IP is not allowed by whitelist. |
+| `403` | `read_only` | Mutating endpoint called while `read_only=true`. |
+| `404` | `not_found` | Unknown route, unknown user, or unsupported sub-route (including current `rotate-secret` route). |
+| `405` | `method_not_allowed` | Unsupported method for `/v1/users/{username}` route shape. |
+| `409` | `revision_conflict` | `If-Match` revision mismatch. |
+| `409` | `user_exists` | User already exists on create. |
+| `409` | `last_user_forbidden` | Attempt to delete last configured user. |
+| `413` | `payload_too_large` | Body exceeds `request_body_limit_bytes`. |
+| `500` | `internal_error` | Internal error (I/O, serialization, config load/save). |
+| `503` | `api_disabled` | API disabled in config. |
+
+## Routing and Method Edge Cases
+
+| Case | Behavior |
+| --- | --- |
+| Path matching | Exact match on `req.uri().path()`. Query string does not affect route matching. |
+| Trailing slash | Not normalized. Example: `/v1/users/` is `404`. |
+| Username route with extra slash | `/v1/users/{username}/...` is not treated as user route and returns `404`. |
+| `PUT /v1/users/{username}` | `405 method_not_allowed`. |
+| `POST /v1/users/{username}` | `404 not_found`. |
+| `POST /v1/users/{username}/rotate-secret` | `404 not_found` in current release due route matcher limitation. |
+
+## Body and JSON Semantics
+
+- Request body is read only for mutating routes that define a body contract.
+- Body size limit is enforced during streaming read (`413 payload_too_large`).
+- Invalid transport body frame returns `400 bad_request` (`Invalid request body`).
+- Invalid JSON returns `400 bad_request` (`Invalid JSON body`).
+- `Content-Type` is not required for JSON parsing.
+- Unknown JSON fields are ignored by deserialization.
+- `PATCH` updates only provided fields and does not support explicit clearing of optional fields.
+- `If-Match` supports both quoted and unquoted values; surrounding whitespace is trimmed.
+
+## Request Contracts
+
+### `CreateUserRequest`
+| Field | Type | Required | Description |
+| --- | --- | --- | --- |
+| `username` | `string` | yes | `[A-Za-z0-9_.-]`, length `1..64`. |
+| `secret` | `string` | no | Exactly 32 hex chars. If missing, generated automatically. |
+| `user_ad_tag` | `string` | no | Exactly 32 hex chars. |
+| `max_tcp_conns` | `usize` | no | Per-user concurrent TCP limit. |
+| `expiration_rfc3339` | `string` | no | RFC3339 expiration timestamp. |
+| `data_quota_bytes` | `u64` | no | Per-user traffic quota. |
+| `max_unique_ips` | `usize` | no | Per-user unique source IP limit. |
+
+### `PatchUserRequest`
+| Field | Type | Required | Description |
+| --- | --- | --- | --- |
+| `secret` | `string` | no | Exactly 32 hex chars. |
+| `user_ad_tag` | `string` | no | Exactly 32 hex chars. |
+| `max_tcp_conns` | `usize` | no | Per-user concurrent TCP limit. |
+| `expiration_rfc3339` | `string` | no | RFC3339 expiration timestamp. |
+| `data_quota_bytes` | `u64` | no | Per-user traffic quota. |
+| `max_unique_ips` | `usize` | no | Per-user unique source IP limit. |
+
+### `RotateSecretRequest`
+| Field | Type | Required | Description |
+| --- | --- | --- | --- |
+| `secret` | `string` | no | Exactly 32 hex chars. If missing, generated automatically. |
+
+Note: the request contract is defined, but the corresponding route currently returns `404` (see routing edge cases).
+
+## Response Data Contracts
+
+### `HealthData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `status` | `string` | Always `"ok"`. |
+| `read_only` | `bool` | Mirrors current API `read_only` mode. |
+
+### `SummaryData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `uptime_seconds` | `f64` | Process uptime in seconds. |
+| `connections_total` | `u64` | Total accepted client connections. |
+| `connections_bad_total` | `u64` | Failed/invalid client connections. |
+| `handshake_timeouts_total` | `u64` | Handshake timeout count. |
+| `configured_users` | `usize` | Number of configured users in config. |
+
+### `SystemInfoData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `version` | `string` | Binary version (`CARGO_PKG_VERSION`). |
+| `target_arch` | `string` | Target architecture (`std::env::consts::ARCH`). |
+| `target_os` | `string` | Target OS (`std::env::consts::OS`). |
+| `build_profile` | `string` | Build profile (`PROFILE` env when available). |
+| `git_commit` | `string?` | Optional commit hash from build env metadata. |
+| `build_time_utc` | `string?` | Optional build timestamp from build env metadata. |
+| `rustc_version` | `string?` | Optional compiler version from build env metadata. |
+| `process_started_at_epoch_secs` | `u64` | Process start time as Unix epoch seconds. |
+| `uptime_seconds` | `f64` | Process uptime in seconds. |
+| `config_path` | `string` | Active config file path used by runtime. |
+| `config_hash` | `string` | SHA-256 hash of current config content (same value as envelope `revision`). |
+| `config_reload_count` | `u64` | Number of successfully observed config updates since process start. |
+| `last_config_reload_epoch_secs` | `u64?` | Unix epoch seconds of the latest observed config reload; null/absent before first reload. |
+
+### `RuntimeGatesData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `accepting_new_connections` | `bool` | Current admission-gate state for new listener accepts. |
+| `conditional_cast_enabled` | `bool` | Whether conditional ME admission logic is enabled (`general.use_middle_proxy`). |
+| `me_runtime_ready` | `bool` | Current ME runtime readiness status used for conditional gate decisions. |
+| `me2dc_fallback_enabled` | `bool` | Whether ME -> direct fallback is enabled. |
+| `use_middle_proxy` | `bool` | Current transport mode preference. |
+
+### `EffectiveLimitsData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `update_every_secs` | `u64` | Effective unified updater interval. |
+| `me_reinit_every_secs` | `u64` | Effective ME periodic reinit interval. |
+| `me_pool_force_close_secs` | `u64` | Effective stale-writer force-close timeout. |
+| `timeouts` | `EffectiveTimeoutLimits` | Effective timeout policy snapshot. |
+| `upstream` | `EffectiveUpstreamLimits` | Effective upstream connect/retry limits. |
+| `middle_proxy` | `EffectiveMiddleProxyLimits` | Effective ME pool/floor/reconnect limits. |
+| `user_ip_policy` | `EffectiveUserIpPolicyLimits` | Effective unique-IP policy mode/window. |
+
+#### `EffectiveTimeoutLimits`
+| Field | Type | Description |
+| --- | --- | --- |
+| `client_handshake_secs` | `u64` | Client handshake timeout. |
+| `tg_connect_secs` | `u64` | Upstream Telegram connect timeout. |
+| `client_keepalive_secs` | `u64` | Client keepalive interval. |
+| `client_ack_secs` | `u64` | ACK timeout. |
+| `me_one_retry` | `u8` | Fast retry count for single-endpoint ME DC. |
+| `me_one_timeout_ms` | `u64` | Fast retry timeout per attempt for single-endpoint ME DC. |
+
+#### `EffectiveUpstreamLimits`
+| Field | Type | Description |
+| --- | --- | --- |
+| `connect_retry_attempts` | `u32` | Upstream connect retry attempts. |
+| `connect_retry_backoff_ms` | `u64` | Upstream retry backoff delay. |
+| `connect_budget_ms` | `u64` | Total connect wall-clock budget across retries. |
+| `unhealthy_fail_threshold` | `u32` | Consecutive fail threshold for unhealthy marking. |
+| `connect_failfast_hard_errors` | `bool` | Whether hard errors skip additional retries. |
+
+#### `EffectiveMiddleProxyLimits`
+| Field | Type | Description |
+| --- | --- | --- |
+| `floor_mode` | `string` | Effective floor mode (`static` or `adaptive`). |
+| `adaptive_floor_idle_secs` | `u64` | Adaptive floor idle threshold. |
+| `adaptive_floor_min_writers_single_endpoint` | `u8` | Adaptive floor minimum for single-endpoint DCs. |
+| `adaptive_floor_recover_grace_secs` | `u64` | Adaptive floor recovery grace period. |
+| `reconnect_max_concurrent_per_dc` | `u32` | Max concurrent reconnects per DC. |
+| `reconnect_backoff_base_ms` | `u64` | Reconnect base backoff. |
+| `reconnect_backoff_cap_ms` | `u64` | Reconnect backoff cap. |
+| `reconnect_fast_retry_count` | `u32` | Number of fast retries before standard backoff strategy. |
+| `me2dc_fallback` | `bool` | Effective ME -> direct fallback flag. |
+
+#### `EffectiveUserIpPolicyLimits`
+| Field | Type | Description |
+| --- | --- | --- |
+| `mode` | `string` | Unique-IP policy mode (`active_window`, `time_window`, `combined`). |
+| `window_secs` | `u64` | Time window length used by unique-IP policy. |
+
+### `SecurityPostureData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `api_read_only` | `bool` | Current API read-only state. |
+| `api_whitelist_enabled` | `bool` | Whether whitelist filtering is active. |
+| `api_whitelist_entries` | `usize` | Number of configured whitelist CIDRs. |
+| `api_auth_header_enabled` | `bool` | Whether `Authorization` header validation is active. |
+| `proxy_protocol_enabled` | `bool` | Global PROXY protocol accept setting. |
+| `log_level` | `string` | Effective log level (`debug`, `verbose`, `normal`, `silent`). |
+| `telemetry_core_enabled` | `bool` | Core telemetry toggle. |
+| `telemetry_user_enabled` | `bool` | Per-user telemetry toggle. |
+| `telemetry_me_level` | `string` | ME telemetry level (`silent`, `normal`, `debug`). |
+
+### `SecurityWhitelistData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `generated_at_epoch_secs` | `u64` | Snapshot generation timestamp. |
+| `enabled` | `bool` | `true` when whitelist has at least one CIDR entry. |
+| `entries_total` | `usize` | Number of whitelist CIDR entries. |
+| `entries` | `string[]` | Whitelist CIDR entries as strings. |
+
+### Runtime Min Endpoints
+- `/v1/runtime/me_pool_state`: generations, hardswap state, writer contour/health counts, refill inflight snapshot.
+- `/v1/runtime/me_quality`: ME error/drift/reconnect counters and per-DC RTT coverage snapshot.
+- `/v1/runtime/upstream_quality`: upstream runtime policy, connect counters, health summary and per-upstream DC latency/IP preference.
+- `/v1/runtime/nat_stun`: NAT/STUN runtime flags, server lists, reflection cache state and backoff remaining.
+
+### Runtime Edge Endpoints
+- `/v1/runtime/connections/summary`: cached connection totals (`total/me/direct`), active users and top-N users by connections/traffic.
+- `/v1/runtime/events/recent?limit=N`: bounded control-plane ring-buffer events (`limit` clamped to `[1, 1000]`).
+- If `server.api.runtime_edge_enabled=false`, runtime edge endpoints return `enabled=false` with `reason=feature_disabled`.
+
+### `ZeroAllData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `generated_at_epoch_secs` | `u64` | Snapshot time (Unix epoch seconds). |
+| `core` | `ZeroCoreData` | Core counters and telemetry policy snapshot. |
+| `upstream` | `ZeroUpstreamData` | Upstream connect counters/histogram buckets. |
+| `middle_proxy` | `ZeroMiddleProxyData` | ME protocol/health counters. |
+| `pool` | `ZeroPoolData` | ME pool lifecycle counters. |
+| `desync` | `ZeroDesyncData` | Frame desync counters. |
+
+#### `ZeroCoreData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `uptime_seconds` | `f64` | Process uptime. |
+| `connections_total` | `u64` | Total accepted connections. |
+| `connections_bad_total` | `u64` | Failed/invalid connections. |
+| `handshake_timeouts_total` | `u64` | Handshake timeouts. |
+| `configured_users` | `usize` | Configured user count. |
+| `telemetry_core_enabled` | `bool` | Core telemetry toggle. |
+| `telemetry_user_enabled` | `bool` | User telemetry toggle. |
+| `telemetry_me_level` | `string` | ME telemetry level (`off|normal|verbose`). |
+
+#### `ZeroUpstreamData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `connect_attempt_total` | `u64` | Total upstream connect attempts. |
+| `connect_success_total` | `u64` | Successful upstream connects. |
+| `connect_fail_total` | `u64` | Failed upstream connects. |
+| `connect_failfast_hard_error_total` | `u64` | Fail-fast hard errors. |
+| `connect_attempts_bucket_1` | `u64` | Connect attempts resolved in 1 try. |
+| `connect_attempts_bucket_2` | `u64` | Connect attempts resolved in 2 tries. |
+| `connect_attempts_bucket_3_4` | `u64` | Connect attempts resolved in 3-4 tries. |
+| `connect_attempts_bucket_gt_4` | `u64` | Connect attempts requiring more than 4 tries. |
+| `connect_duration_success_bucket_le_100ms` | `u64` | Successful connects <=100 ms. |
+| `connect_duration_success_bucket_101_500ms` | `u64` | Successful connects 101-500 ms. |
+| `connect_duration_success_bucket_501_1000ms` | `u64` | Successful connects 501-1000 ms. |
+| `connect_duration_success_bucket_gt_1000ms` | `u64` | Successful connects >1000 ms. |
+| `connect_duration_fail_bucket_le_100ms` | `u64` | Failed connects <=100 ms. |
+| `connect_duration_fail_bucket_101_500ms` | `u64` | Failed connects 101-500 ms. |
+| `connect_duration_fail_bucket_501_1000ms` | `u64` | Failed connects 501-1000 ms. |
+| `connect_duration_fail_bucket_gt_1000ms` | `u64` | Failed connects >1000 ms. |
+
+### `UpstreamsData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `enabled` | `bool` | Runtime upstream snapshot availability according to API config. |
+| `reason` | `string?` | `feature_disabled` or `source_unavailable` when runtime snapshot is unavailable. |
+| `generated_at_epoch_secs` | `u64` | Snapshot generation time. |
+| `zero` | `ZeroUpstreamData` | Always available zero-cost upstream counters block. |
+| `summary` | `UpstreamSummaryData?` | Runtime upstream aggregate view, null when unavailable. |
+| `upstreams` | `UpstreamStatus[]?` | Per-upstream runtime status rows, null when unavailable. |
+
+#### `UpstreamSummaryData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `configured_total` | `usize` | Total configured upstream entries. |
+| `healthy_total` | `usize` | Upstreams currently marked healthy. |
+| `unhealthy_total` | `usize` | Upstreams currently marked unhealthy. |
+| `direct_total` | `usize` | Number of direct upstream entries. |
+| `socks4_total` | `usize` | Number of SOCKS4 upstream entries. |
+| `socks5_total` | `usize` | Number of SOCKS5 upstream entries. |
+
+#### `UpstreamStatus`
+| Field | Type | Description |
+| --- | --- | --- |
+| `upstream_id` | `usize` | Runtime upstream index. |
+| `route_kind` | `string` | Upstream route kind: `direct`, `socks4`, `socks5`. |
+| `address` | `string` | Upstream address (`direct` for direct route kind). Authentication fields are intentionally omitted. |
+| `weight` | `u16` | Selection weight. |
+| `scopes` | `string` | Configured scope selector string. |
+| `healthy` | `bool` | Current health flag. |
+| `fails` | `u32` | Consecutive fail counter. |
+| `last_check_age_secs` | `u64` | Seconds since the last health-check update. |
+| `effective_latency_ms` | `f64?` | Effective upstream latency used by selector. |
+| `dc` | `UpstreamDcStatus[]` | Per-DC latency/IP preference snapshot. |
+
+#### `UpstreamDcStatus`
+| Field | Type | Description |
+| --- | --- | --- |
+| `dc` | `i16` | Telegram DC id. |
+| `latency_ema_ms` | `f64?` | Per-DC latency EMA value. |
+| `ip_preference` | `string` | Per-DC IP family preference: `unknown`, `prefer_v4`, `prefer_v6`, `both_work`, `unavailable`. |
+
+#### `ZeroMiddleProxyData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `keepalive_sent_total` | `u64` | ME keepalive packets sent. |
+| `keepalive_failed_total` | `u64` | ME keepalive send failures. |
+| `keepalive_pong_total` | `u64` | Keepalive pong responses received. |
+| `keepalive_timeout_total` | `u64` | Keepalive timeout events. |
+| `rpc_proxy_req_signal_sent_total` | `u64` | RPC proxy activity signals sent. |
+| `rpc_proxy_req_signal_failed_total` | `u64` | RPC proxy activity signal failures. |
+| `rpc_proxy_req_signal_skipped_no_meta_total` | `u64` | Signals skipped due to missing metadata. |
+| `rpc_proxy_req_signal_response_total` | `u64` | RPC proxy signal responses received. |
+| `rpc_proxy_req_signal_close_sent_total` | `u64` | RPC proxy close signals sent. |
+| `reconnect_attempt_total` | `u64` | ME reconnect attempts. |
+| `reconnect_success_total` | `u64` | Successful reconnects. |
+| `handshake_reject_total` | `u64` | ME handshake rejects. |
+| `handshake_error_codes` | `ZeroCodeCount[]` | Handshake rejects grouped by code. |
+| `reader_eof_total` | `u64` | ME reader EOF events. |
+| `idle_close_by_peer_total` | `u64` | Idle closes initiated by peer. |
+| `route_drop_no_conn_total` | `u64` | Route drops due to missing bound connection. |
+| `route_drop_channel_closed_total` | `u64` | Route drops due to closed channel. |
+| `route_drop_queue_full_total` | `u64` | Route drops due to full queue (total). |
+| `route_drop_queue_full_base_total` | `u64` | Route drops in base queue mode. |
+| `route_drop_queue_full_high_total` | `u64` | Route drops in high queue mode. |
+| `socks_kdf_strict_reject_total` | `u64` | SOCKS KDF strict rejects. |
+| `socks_kdf_compat_fallback_total` | `u64` | SOCKS KDF compat fallbacks. |
+| `endpoint_quarantine_total` | `u64` | Endpoint quarantine activations. |
+| `kdf_drift_total` | `u64` | KDF drift detections. |
+| `kdf_port_only_drift_total` | `u64` | KDF port-only drift detections. |
+| `hardswap_pending_reuse_total` | `u64` | Pending hardswap reused events. |
+| `hardswap_pending_ttl_expired_total` | `u64` | Pending hardswap TTL expiry events. |
+| `single_endpoint_outage_enter_total` | `u64` | Entered single-endpoint outage mode. |
+| `single_endpoint_outage_exit_total` | `u64` | Exited single-endpoint outage mode. |
+| `single_endpoint_outage_reconnect_attempt_total` | `u64` | Reconnect attempts in outage mode. |
+| `single_endpoint_outage_reconnect_success_total` | `u64` | Reconnect successes in outage mode. |
+| `single_endpoint_quarantine_bypass_total` | `u64` | Quarantine bypasses in outage mode. |
+| `single_endpoint_shadow_rotate_total` | `u64` | Shadow writer rotations. |
+| `single_endpoint_shadow_rotate_skipped_quarantine_total` | `u64` | Shadow rotations skipped because of quarantine. |
+| `floor_mode_switch_total` | `u64` | Total floor mode switches. |
+| `floor_mode_switch_static_to_adaptive_total` | `u64` | Static -> adaptive switches. |
+| `floor_mode_switch_adaptive_to_static_total` | `u64` | Adaptive -> static switches. |
+
+#### `ZeroCodeCount`
+| Field | Type | Description |
+| --- | --- | --- |
+| `code` | `i32` | Handshake error code. |
+| `total` | `u64` | Events with this code. |
+
+#### `ZeroPoolData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `pool_swap_total` | `u64` | Pool swap count. |
+| `pool_drain_active` | `u64` | Current active draining pools. |
+| `pool_force_close_total` | `u64` | Forced pool closes by timeout. |
+| `pool_stale_pick_total` | `u64` | Stale writer picks for binding. |
+| `writer_removed_total` | `u64` | Writer removals total. |
+| `writer_removed_unexpected_total` | `u64` | Unexpected writer removals. |
+| `refill_triggered_total` | `u64` | Refill triggers. |
+| `refill_skipped_inflight_total` | `u64` | Refill skipped because refill already in-flight. |
+| `refill_failed_total` | `u64` | Refill failures. |
+| `writer_restored_same_endpoint_total` | `u64` | Restores on same endpoint. |
+| `writer_restored_fallback_total` | `u64` | Restores on fallback endpoint. |
+
+#### `ZeroDesyncData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `secure_padding_invalid_total` | `u64` | Invalid secure padding events. |
+| `desync_total` | `u64` | Desync events total. |
+| `desync_full_logged_total` | `u64` | Fully logged desync events. |
+| `desync_suppressed_total` | `u64` | Suppressed desync logs. |
+| `desync_frames_bucket_0` | `u64` | Desync frames bucket 0. |
+| `desync_frames_bucket_1_2` | `u64` | Desync frames bucket 1-2. |
+| `desync_frames_bucket_3_10` | `u64` | Desync frames bucket 3-10. |
+| `desync_frames_bucket_gt_10` | `u64` | Desync frames bucket >10. |
+
+### `MinimalAllData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `enabled` | `bool` | Whether minimal runtime snapshots are enabled by config. |
+| `reason` | `string?` | `feature_disabled` or `source_unavailable` when applicable. |
+| `generated_at_epoch_secs` | `u64` | Snapshot generation time. |
+| `data` | `MinimalAllPayload?` | Null when disabled; fallback payload when source unavailable. |
+
+#### `MinimalAllPayload`
+| Field | Type | Description |
+| --- | --- | --- |
+| `me_writers` | `MeWritersData` | ME writer status block. |
+| `dcs` | `DcStatusData` | DC aggregate status block. |
+| `me_runtime` | `MinimalMeRuntimeData?` | Runtime ME control snapshot. |
+| `network_path` | `MinimalDcPathData[]` | Active IP path selection per DC. |
+
+#### `MinimalMeRuntimeData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `active_generation` | `u64` | Active pool generation. |
+| `warm_generation` | `u64` | Warm pool generation. |
+| `pending_hardswap_generation` | `u64` | Pending hardswap generation. |
+| `pending_hardswap_age_secs` | `u64?` | Pending hardswap age in seconds. |
+| `hardswap_enabled` | `bool` | Hardswap mode toggle. |
+| `floor_mode` | `string` | Writer floor mode. |
+| `adaptive_floor_idle_secs` | `u64` | Idle threshold for adaptive floor. |
+| `adaptive_floor_min_writers_single_endpoint` | `u8` | Minimum writers for single-endpoint DC in adaptive mode. |
+| `adaptive_floor_recover_grace_secs` | `u64` | Grace period for floor recovery. |
+| `me_keepalive_enabled` | `bool` | ME keepalive toggle. |
+| `me_keepalive_interval_secs` | `u64` | Keepalive period. |
+| `me_keepalive_jitter_secs` | `u64` | Keepalive jitter. |
+| `me_keepalive_payload_random` | `bool` | Randomized keepalive payload toggle. |
+| `rpc_proxy_req_every_secs` | `u64` | Period for RPC proxy request signal. |
+| `me_reconnect_max_concurrent_per_dc` | `u32` | Reconnect concurrency per DC. |
+| `me_reconnect_backoff_base_ms` | `u64` | Base reconnect backoff. |
+| `me_reconnect_backoff_cap_ms` | `u64` | Max reconnect backoff. |
+| `me_reconnect_fast_retry_count` | `u32` | Fast retry attempts before normal backoff. |
+| `me_pool_drain_ttl_secs` | `u64` | Pool drain TTL. |
+| `me_pool_force_close_secs` | `u64` | Hard close timeout for draining writers. |
+| `me_pool_min_fresh_ratio` | `f32` | Minimum fresh ratio before swap. |
+| `me_bind_stale_mode` | `string` | Stale writer bind policy. |
+| `me_bind_stale_ttl_secs` | `u64` | Stale writer TTL. |
+| `me_single_endpoint_shadow_writers` | `u8` | Shadow writers for single-endpoint DCs. |
+| `me_single_endpoint_outage_mode_enabled` | `bool` | Outage mode toggle for single-endpoint DCs. |
+| `me_single_endpoint_outage_disable_quarantine` | `bool` | Quarantine behavior in outage mode. |
+| `me_single_endpoint_outage_backoff_min_ms` | `u64` | Outage mode min reconnect backoff. |
+| `me_single_endpoint_outage_backoff_max_ms` | `u64` | Outage mode max reconnect backoff. |
+| `me_single_endpoint_shadow_rotate_every_secs` | `u64` | Shadow rotation interval. |
+| `me_deterministic_writer_sort` | `bool` | Deterministic writer ordering toggle. |
+| `me_socks_kdf_policy` | `string` | Current SOCKS KDF policy mode. |
+| `quarantined_endpoints_total` | `usize` | Total quarantined endpoints. |
+| `quarantined_endpoints` | `MinimalQuarantineData[]` | Quarantine details. |
+
+#### `MinimalQuarantineData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `endpoint` | `string` | Endpoint (`ip:port`). |
+| `remaining_ms` | `u64` | Remaining quarantine duration. |
+
+#### `MinimalDcPathData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `dc` | `i16` | Telegram DC identifier. |
+| `ip_preference` | `string?` | Runtime IP family preference. |
+| `selected_addr_v4` | `string?` | Selected IPv4 endpoint for this DC. |
+| `selected_addr_v6` | `string?` | Selected IPv6 endpoint for this DC. |
+
+### `MeWritersData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `middle_proxy_enabled` | `bool` | `false` when minimal runtime is disabled or source unavailable. |
+| `reason` | `string?` | `feature_disabled` or `source_unavailable` when not fully available. |
+| `generated_at_epoch_secs` | `u64` | Snapshot generation time. |
+| `summary` | `MeWritersSummary` | Coverage/availability summary. |
+| `writers` | `MeWriterStatus[]` | Per-writer statuses. |
+
+#### `MeWritersSummary`
+| Field | Type | Description |
+| --- | --- | --- |
+| `configured_dc_groups` | `usize` | Number of configured DC groups. |
+| `configured_endpoints` | `usize` | Total configured ME endpoints. |
+| `available_endpoints` | `usize` | Endpoints currently available. |
+| `available_pct` | `f64` | `available_endpoints / configured_endpoints * 100`. |
+| `required_writers` | `usize` | Required writers based on current floor policy. |
+| `alive_writers` | `usize` | Writers currently alive. |
+| `coverage_pct` | `f64` | `alive_writers / required_writers * 100`. |
+
+#### `MeWriterStatus`
+| Field | Type | Description |
+| --- | --- | --- |
+| `writer_id` | `u64` | Runtime writer identifier. |
+| `dc` | `i16?` | DC id if mapped. |
+| `endpoint` | `string` | Endpoint (`ip:port`). |
+| `generation` | `u64` | Pool generation owning this writer. |
+| `state` | `string` | Writer state (`warm`, `active`, `draining`). |
+| `draining` | `bool` | Draining flag. |
+| `degraded` | `bool` | Degraded flag. |
+| `bound_clients` | `usize` | Number of currently bound clients. |
+| `idle_for_secs` | `u64?` | Idle age in seconds if idle. |
+| `rtt_ema_ms` | `f64?` | RTT exponential moving average. |
+
+### `DcStatusData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `middle_proxy_enabled` | `bool` | `false` when minimal runtime is disabled or source unavailable. |
+| `reason` | `string?` | `feature_disabled` or `source_unavailable` when not fully available. |
+| `generated_at_epoch_secs` | `u64` | Snapshot generation time. |
+| `dcs` | `DcStatus[]` | Per-DC status rows. |
+
+#### `DcStatus`
+| Field | Type | Description |
+| --- | --- | --- |
+| `dc` | `i16` | Telegram DC id. |
+| `endpoints` | `string[]` | Endpoints in this DC (`ip:port`). |
+| `available_endpoints` | `usize` | Endpoints currently available in this DC. |
+| `available_pct` | `f64` | `available_endpoints / endpoints_total * 100`. |
+| `required_writers` | `usize` | Required writer count for this DC. |
+| `alive_writers` | `usize` | Alive writers in this DC. |
+| `coverage_pct` | `f64` | `alive_writers / required_writers * 100`. |
+| `rtt_ms` | `f64?` | Aggregated RTT for DC. |
+| `load` | `usize` | Active client sessions bound to this DC. |
+
+### `UserInfo`
+| Field | Type | Description |
+| --- | --- | --- |
+| `username` | `string` | Username. |
+| `user_ad_tag` | `string?` | Optional ad tag (32 hex chars). |
+| `max_tcp_conns` | `usize?` | Optional max concurrent TCP limit. |
+| `expiration_rfc3339` | `string?` | Optional expiration timestamp. |
+| `data_quota_bytes` | `u64?` | Optional data quota. |
+| `max_unique_ips` | `usize?` | Optional unique IP limit. |
+| `current_connections` | `u64` | Current live connections. |
+| `active_unique_ips` | `usize` | Current active unique source IPs. |
+| `total_octets` | `u64` | Total traffic octets for this user. |
+| `links` | `UserLinks` | Active connection links derived from current config. |
+
+#### `UserLinks`
+| Field | Type | Description |
+| --- | --- | --- |
+| `classic` | `string[]` | Active `tg://proxy` links for classic mode. |
+| `secure` | `string[]` | Active `tg://proxy` links for secure/DD mode. |
+| `tls` | `string[]` | Active `tg://proxy` links for EE-TLS mode (for each host+TLS domain). |
+
+Link generation uses active config and enabled modes:
+- `[general.links].public_host/public_port` have priority.
+- If `public_host` is not set, startup-detected public IPs are used (`IPv4`, `IPv6`, or both when available).
+- Fallback host sources: listener `announce`, `announce_ip`, explicit listener `ip`.
+- Legacy fallback: `listen_addr_ipv4` and `listen_addr_ipv6` when routable.
+- Startup-detected IPs are fixed for process lifetime and refreshed on restart.
+- User rows are sorted by `username` in ascending lexical order.
+
+### `CreateUserResponse`
+| Field | Type | Description |
+| --- | --- | --- |
+| `user` | `UserInfo` | Created or updated user view. |
+| `secret` | `string` | Effective user secret. |
+
+## Mutation Semantics
+
+| Endpoint | Notes |
+| --- | --- |
+| `POST /v1/users` | Creates user and validates resulting config before atomic save. |
+| `PATCH /v1/users/{username}` | Partial update of provided fields only. Missing fields remain unchanged. |
+| `POST /v1/users/{username}/rotate-secret` | Currently returns `404` in runtime route matcher; request schema is reserved for intended behavior. |
+| `DELETE /v1/users/{username}` | Deletes user and related optional settings. Last user deletion is blocked. |
+
+All mutating endpoints:
+- Respect `read_only` mode.
+- Accept optional `If-Match` for optimistic concurrency.
+- Return new `revision` after successful write.
+- Use process-local mutation lock + atomic write (`tmp + rename`) for config persistence.
+
+## Runtime State Matrix
+
+| Endpoint | `minimal_runtime_enabled=false` | `minimal_runtime_enabled=true` + source unavailable | `minimal_runtime_enabled=true` + source available |
+| --- | --- | --- | --- |
+| `/v1/stats/minimal/all` | `enabled=false`, `reason=feature_disabled`, `data=null` | `enabled=true`, `reason=source_unavailable`, fallback `data` with disabled ME blocks | `enabled=true`, `reason` omitted, full payload |
+| `/v1/stats/me-writers` | `middle_proxy_enabled=false`, `reason=feature_disabled` | `middle_proxy_enabled=false`, `reason=source_unavailable` | `middle_proxy_enabled=true`, runtime snapshot |
+| `/v1/stats/dcs` | `middle_proxy_enabled=false`, `reason=feature_disabled` | `middle_proxy_enabled=false`, `reason=source_unavailable` | `middle_proxy_enabled=true`, runtime snapshot |
+| `/v1/stats/upstreams` | `enabled=false`, `reason=feature_disabled`, `summary/upstreams` omitted, `zero` still present | `enabled=true`, `reason=source_unavailable`, `summary/upstreams` omitted, `zero` present | `enabled=true`, `reason` omitted, `summary/upstreams` present, `zero` present |
+
+`source_unavailable` conditions:
+- ME endpoints: ME pool is absent (for example direct-only mode or failed ME initialization).
+- Upstreams endpoint: non-blocking upstream snapshot lock is unavailable at request time.
+
+## Serialization Rules
+
+- Success responses always include `revision`.
+- Error responses never include `revision`; they include `request_id`.
+- Optional fields with `skip_serializing_if` are omitted when absent.
+- Nullable payload fields may still be `null` where contract uses `?` (for example `UserInfo` option fields).
+- For `/v1/stats/upstreams`, authentication details of SOCKS upstreams are intentionally omitted.
+
+## Operational Notes
+
+| Topic | Details |
+| --- | --- |
+| API startup | API listener is spawned only when `[server.api].enabled=true`. |
+| `listen` port `0` | API spawn is skipped when parsed listen port is `0` (treated as disabled bind target). |
+| Bind failure | Failed API bind logs warning and API task exits (no auto-retry loop). |
+| ME runtime status endpoints | `/v1/stats/me-writers`, `/v1/stats/dcs`, `/v1/stats/minimal/all` require `[server.api].minimal_runtime_enabled=true`; otherwise they return disabled payload with `reason=feature_disabled`. |
+| Upstream runtime endpoint | `/v1/stats/upstreams` always returns `zero`, but runtime fields (`summary`, `upstreams`) require `[server.api].minimal_runtime_enabled=true`. |
+| Restart requirements | `server.api` changes are restart-required for predictable behavior. |
+| Hot-reload nuance | A pure `server.api`-only config change may not propagate through watcher broadcast; a mixed change (with hot fields) may propagate API flags while still warning that restart is required. |
+| Runtime apply path | Successful writes are picked up by existing config watcher/hot-reload path. |
+| Exposure | Built-in TLS/mTLS is not provided. Use loopback bind + reverse proxy if needed. |
+| Pagination | User list currently has no pagination/filtering. |
+| Serialization side effect | Config comments/manual formatting are not preserved on write. |
+
+## Known Limitations (Current Release)
+
+- `POST /v1/users/{username}/rotate-secret` is currently unreachable in route matcher and returns `404`.
+- API runtime controls under `server.api` are documented as restart-required; hot-reload behavior for these fields is not strictly uniform in all change combinations.

docs/FAQ.en.md

@@ -0,0 +1,112 @@
+## How to set up "proxy sponsor" channel and statistics via @MTProxybot bot
+
+1. Go to @MTProxybot bot.
+2. Enter the command `/newproxy`
+3. Send the server IP and port. For example: 1.2.3.4:443
+4. Open the config `nano /etc/telemt.toml`.
+5. Copy and send the user secret from the [access.users] section to the bot.
+6. Copy the tag received from the bot. For example 1234567890abcdef1234567890abcdef.
+> [!WARNING]
+> The link provided by the bot will not work. Do not copy or use it!
+7. Uncomment the ad_tag parameter and enter the tag received from the bot.
+8. Uncomment/add the parameter `use_middle_proxy = true`.
+
+Config example:
+```toml
+[general]
+ad_tag = "1234567890abcdef1234567890abcdef"
+use_middle_proxy = true
+```
+9. Save the config. Ctrl+S -> Ctrl+X.
+10. Restart telemt `systemctl restart telemt`.
+11. In the bot, send the command /myproxies and select the added server.
+12. Click the "Set promotion" button.
+13. Send a **public link** to the channel. Private channels cannot be added!
+14. Wait approximately 1 hour for the information to update on Telegram servers.
+> [!WARNING]
+> You will not see the "proxy sponsor" if you are already subscribed to the channel.
+
+**You can also set up different channels for different users.**
+```toml
+[access.user_ad_tags]
+hello = "ad_tag"
+hello2 = "ad_tag2"
+```
+
+## How many people can use 1 link
+
+By default, 1 link can be used by any number of people.  
+You can limit the number of IPs using the proxy.
+```toml
+[access.user_max_unique_ips]
+hello = 1
+```
+This parameter limits how many unique IPs can use 1 link simultaneously. If one user disconnects, a second user can connect. Also, multiple users can sit behind the same IP.
+
+## How to create multiple different links
+
+1. Generate the required number of secrets `openssl rand -hex 16`
+2. Open the config `nano /etc/telemt.toml`
+3. Add new users.
+```toml
+[access.users]
+user1 = "00000000000000000000000000000001"
+user2 = "00000000000000000000000000000002"
+user3 = "00000000000000000000000000000003"
+```
+4. Save the config. Ctrl+S -> Ctrl+X. You don't need to restart telemt.
+5. Get the links via `journalctl -u telemt -n -g "links" --no-pager -o cat | tac`
+
+## How to view metrics
+
+1. Open the config `nano /etc/telemt.toml`
+2. Add the following parameters
+```toml
+[server]
+metrics_port = 9090
+metrics_whitelist = ["127.0.0.1/32", "::1/128", "0.0.0.0/0"]
+```
+3. Save the config. Ctrl+S -> Ctrl+X.
+4. Metrics are available at SERVER_IP:9090/metrics.
+> [!WARNING]
+> "0.0.0.0/0" in metrics_whitelist opens access from any IP. Replace with your own IP. For example "1.2.3.4"
+
+## Additional parameters
+
+### Domain in link instead of IP
+To specify a domain in the links, add to the `[general.links]` section of the config file.
+```toml
+[general.links]
+public_host = "proxy.example.com"
+```
+
+### Upstream Manager
+To specify an upstream, add to the `[[upstreams]]` section of the config.toml file:
+#### Binding to IP
+```toml
+[[upstreams]]
+type = "direct"
+weight = 1
+enabled = true
+interface = "192.168.1.100" # Change to your outgoing IP
+```
+#### SOCKS4/5 as Upstream
+- Without authentication:
+```toml
+[[upstreams]]
+type = "socks5"            # Specify SOCKS4 or SOCKS5
+address = "1.2.3.4:1234"   # SOCKS-server Address
+weight = 1                 # Set Weight for Scenarios
+enabled = true
+```
+
+- With authentication:
+```toml
+[[upstreams]]
+type = "socks5"            # Specify SOCKS4 or SOCKS5
+address = "1.2.3.4:1234"   # SOCKS-server Address
+username = "user"          # Username for Auth on SOCKS-server
+password = "pass"          # Password for Auth on SOCKS-server
+weight = 1                 # Set Weight for Scenarios
+enabled = true
+```

docs/FAQ.ru.md

@@ -0,0 +1,112 @@
+## Как настроить канал "спонсор прокси" и статистику через бота @MTProxybot
+
+1. Зайти в бота @MTProxybot.
+2. Ввести команду `/newproxy`
+3. Отправить IP и порт сервера. Например: 1.2.3.4:443
+4. Открыть конфиг `nano /etc/telemt.toml`.
+5. Скопировать и отправить боту секрет пользователя из раздела [access.users].
+6. Скопировать полученный tag у бота. Например 1234567890abcdef1234567890abcdef.
+> [!WARNING]
+> Ссылка, которую выдает бот, не будет работать. Не копируйте и не используйте её!
+7. Раскомментировать параметр ad_tag и вписать tag, полученный у бота.
+8. Раскомментировать/добавить параметр use_middle_proxy = true.
+
+Пример конфига:
+```toml
+[general]
+ad_tag = "1234567890abcdef1234567890abcdef"
+use_middle_proxy = true
+```
+9.  Сохранить конфиг. Ctrl+S -> Ctrl+X.
+10. Перезапустить telemt `systemctl restart telemt`.
+11. В боте отправить команду /myproxies и выбрать добавленный сервер.
+12. Нажать кнопку "Set promotion".
+13. Отправить **публичную ссылку** на канал. Приватный канал добавить нельзя!
+14. Подождать примерно 1 час, пока информация обновится на серверах Telegram.
+> [!WARNING]
+> У вас не будет отображаться "спонсор прокси" если вы уже подписаны на канал.
+
+**Также вы можете настроить разные каналы для разных пользователей.**
+```toml
+[access.user_ad_tags]
+hello = "ad_tag"
+hello2 = "ad_tag2"
+```
+
+## Сколько человек может пользоваться 1 ссылкой
+
+По умолчанию 1 ссылкой может пользоваться сколько угодно человек.  
+Вы можете ограничить число IP, использующих прокси.
+```toml
+[access.user_max_unique_ips]
+hello = 1
+```
+Этот параметр ограничивает, сколько уникальных IP может использовать 1 ссылку одновременно. Если один пользователь отключится, второй сможет подключиться. Также с одного IP может сидеть несколько пользователей.
+
+## Как сделать несколько разных ссылок
+
+1. Сгенерируйте нужное число секретов `openssl rand -hex 16`
+2. Открыть конфиг `nano /etc/telemt.toml`
+3. Добавить новых пользователей.
+```toml
+[access.users]
+user1 = "00000000000000000000000000000001"
+user2 = "00000000000000000000000000000002"
+user3 = "00000000000000000000000000000003"
+```
+4. Сохранить конфиг. Ctrl+S -> Ctrl+X. Перезапускать telemt не нужно.
+5. Получить ссылки через `journalctl -u telemt -n -g "links" --no-pager -o cat | tac`
+
+## Как посмотреть метрики
+
+1. Открыть конфиг `nano /etc/telemt.toml`
+2. Добавить следующие параметры
+```toml
+[server]
+metrics_port = 9090
+metrics_whitelist = ["127.0.0.1/32", "::1/128", "0.0.0.0/0"]
+```
+3. Сохранить конфиг. Ctrl+S -> Ctrl+X.
+4. Метрики доступны по адресу SERVER_IP:9090/metrics. 
+> [!WARNING]
+> "0.0.0.0/0" в metrics_whitelist открывает доступ с любого IP. Замените на свой ip. Например "1.2.3.4"
+
+## Дополнительные параметры
+
+### Домен в ссылке вместо IP
+Чтобы указать домен в ссылках, добавьте в секцию `[general.links]` файла config.
+```toml
+[general.links]
+public_host = "proxy.example.com"
+```
+
+### Upstream Manager
+Чтобы указать апстрим, добавьте в секцию `[[upstreams]]` файла config.toml:
+#### Привязка к IP
+```toml
+[[upstreams]]
+type = "direct"
+weight = 1
+enabled = true
+interface = "192.168.1.100" # Change to your outgoing IP
+```
+#### SOCKS4/5 как Upstream
+- Без авторизации:
+```toml
+[[upstreams]]
+type = "socks5"            # Specify SOCKS4 or SOCKS5
+address = "1.2.3.4:1234"   # SOCKS-server Address
+weight = 1                 # Set Weight for Scenarios
+enabled = true
+```
+
+- С авторизацией:
+```toml
+[[upstreams]]
+type = "socks5"            # Specify SOCKS4 or SOCKS5
+address = "1.2.3.4:1234"   # SOCKS-server Address
+username = "user"          # Username for Auth on SOCKS-server
+password = "pass"          # Password for Auth on SOCKS-server
+weight = 1                 # Set Weight for Scenarios
+enabled = true
+```

docs/MIDDLE-END-KDF.de.md

@@ -0,0 +1,40 @@
+# Middle-End Proxy
+
+## KDF-Adressierung — Implementierungs-FAQ
+
+### Benötigt die C-Referenzimplementierung sowohl externe IP-Adresse als auch Port für die KDF?
+
+Ja.
+
+In der C-Referenzimplementierung werden **sowohl IP-Adresse als auch Port in die KDF einbezogen** — auf beiden Seiten der Verbindung.
+
+In `aes_create_keys()` enthält der KDF-Input:
+
+- `server_ip + client_port`
+- `client_ip + server_port`
+- sowie Secret / Nonces
+
+Für IPv6:
+
+- IPv4-Felder werden auf 0 gesetzt
+- IPv6-Adressen werden ergänzt
+
+Die **Ports bleiben weiterhin Bestandteil der KDF**.
+
+> Wenn sich externe IP oder Port (z. B. durch NAT, SOCKS oder Proxy) von den erwarteten Werten unterscheiden, entstehen unterschiedliche Schlüssel — der Handshake schlägt fehl.
+
+---
+
+### Kann der Port aus der KDF ausgeschlossen werden (z. B. durch Port = 0)?
+
+**Nein!**
+
+Die C-Referenzimplementierung enthält **keine Möglichkeit, den Port zu ignorieren**:
+- `client_port` und `server_port` sind fester Bestandteil der KDF
+- Es werden immer reale Socket-Ports übergeben:
+  - `c->our_port`
+  - `c->remote_port`
+
+Falls ein Port den Wert `0` hat, wird er dennoch als `0` in die KDF übernommen.
+
+Eine „Port-Ignore“-Logik existiert nicht.

docs/MIDDLE-END-KDF.en.md

@@ -0,0 +1,41 @@
+# Middle-End Proxy
+
+## KDF Addressing — Implementation FAQ
+
+### Does the C-implementation require both external IP address and port for the KDF?
+
+**Yes!**
+
+In the C reference implementation, **both IP address and port are included in the KDF input** from both sides of the connection.
+
+Inside `aes_create_keys()`, the KDF input explicitly contains:
+
+- `server_ip + client_port`
+- `client_ip + server_port`
+- followed by shared secret / nonces
+
+For IPv6:
+
+- IPv4 fields are zeroed
+- IPv6 addresses are inserted
+
+However, **client_port and server_port remain part of the KDF regardless of IP version**.
+
+> If externally observed IP or port (e.g. due to NAT, SOCKS, or proxy traversal) differs from what the peer expects, the derived keys will not match and the handshake will fail.
+
+---
+
+### Can port be excluded from KDF (e.g. by using port = 0)?
+
+**No!**
+
+The C-implementation provides **no mechanism to ignore the port**:
+
+- `client_port` and `server_port` are explicitly included in the KDF input
+- Real socket ports are always passed:
+  - `c->our_port`
+  - `c->remote_port`
+
+If a port is `0`, it is still incorporated into the KDF as `0`.
+
+There is **no conditional logic to exclude ports**

docs/MIDDLE-END-KDF.ru.md

@@ -0,0 +1,41 @@
+# Middle-End Proxy
+
+## KDF Addressing — FAQ по реализации
+
+### Требует ли C-референсная реализация KDF внешний IP и порт?
+
+**Да**
+
+В C-референсе **в KDF участвуют и IP-адрес, и порт** — с обеих сторон соединения.
+
+В `aes_create_keys()` в строку KDF входят:
+
+- `server_ip + client_port`
+- `client_ip + server_port`
+- далее secret / nonces
+
+Для IPv6:
+
+- IPv4-поля заполняются нулями
+- добавляются IPv6-адреса
+
+Однако **порты client_port и server_port всё равно участвуют в KDF**.
+
+> Если внешний IP или порт (например, из-за NAT, SOCKS или прокси) не совпадает с ожидаемым другой стороной — ключи расходятся и handshake ломается.
+
+---
+
+### Можно ли исключить порт из KDF (например, установив порт = 0)?
+
+**Нет.**
+
+В C-референсе **нет механики отключения порта**.
+
+- `client_port` и `server_port` явно включены в KDF
+- Передаются реальные порты сокета:
+  - `c->our_port`
+  - `c->remote_port`
+
+Если порт равен `0`, он всё равно попадёт в KDF как `0`.
+
+Отдельной логики «игнорировать порт» не предусмотрено.

docs/QUICK_START_GUIDE.en.md

@@ -0,0 +1,165 @@
+# Telemt via Systemd
+
+## Installation
+
+This software is designed for Debian-based OS: in addition to Debian, these are Ubuntu, Mint, Kali, MX and many other Linux
+
+**1. Download**
+```bash
+wget -qO- "https://github.com/telemt/telemt/releases/latest/download/telemt-$(uname -m)-linux-$(ldd --version 2>&1 | grep -iq musl && echo musl || echo gnu).tar.gz" | tar -xz
+```
+**2. Move to the Bin folder**
+```bash
+mv telemt /bin
+```
+**3. Make the file executable**
+```bash
+chmod +x /bin/telemt
+```
+
+## How to use?
+
+**This guide "assumes" that you:**
+- logged in as root or executed `su -` / `sudo su`
+- Already have the "telemt" executable file in the /bin folder. Read the **[Installation](#Installation)** section.
+
+---
+
+**0. Check port and generate secrets**
+
+The port you have selected for use should be MISSING from the list, when:
+```bash
+netstat -lnp
+```
+
+Generate 16 bytes/32 characters HEX with OpenSSL or another way:
+```bash
+openssl rand -hex 16
+```
+OR
+```bash
+xxd -l 16 -p /dev/urandom
+```
+OR
+```bash
+python3 -c 'import os; print(os.urandom(16).hex())'
+```
+Save the obtained result somewhere. You will need it later!
+
+---
+
+**1. Place your config to /etc/telemt.toml**
+
+Open nano
+```bash
+nano /etc/telemt.toml
+```
+paste your config
+
+```toml
+# === General Settings ===
+[general]
+# ad_tag = "00000000000000000000000000000000"
+use_middle_proxy = false
+
+[general.modes]
+classic = false
+secure = false
+tls = true
+
+[server.api]
+enabled = true
+# listen = "127.0.0.1:9091"
+# whitelist = ["127.0.0.1/32"]
+# read_only = true
+
+# === Anti-Censorship & Masking ===
+[censorship]
+tls_domain = "petrovich.ru"
+
+[access.users]
+# format: "username" = "32_hex_chars_secret"
+hello = "00000000000000000000000000000000"
+```
+
+then Ctrl+S -> Ctrl+X to save
+
+> [!WARNING]
+> Replace the value of the hello parameter with the value you obtained in step 0. 
+> Replace the value of the tls_domain parameter with another website.
+
+---
+
+**2. Create service on /etc/systemd/system/telemt.service**
+
+Open nano
+```bash
+nano /etc/systemd/system/telemt.service
+```
+
+paste this Systemd Module
+```bash
+[Unit]
+Description=Telemt
+After=network.target
+
+[Service]
+Type=simple
+WorkingDirectory=/bin
+ExecStart=/bin/telemt /etc/telemt.toml
+Restart=on-failure
+LimitNOFILE=65536
+
+[Install]
+WantedBy=multi-user.target
+```
+then Ctrl+S -> Ctrl+X to save
+
+
+**3.** To start it, enter the command `systemctl start telemt`
+
+**4.** To get status information, enter `systemctl status telemt`
+
+**5.** For automatic startup at system boot, enter `systemctl enable telemt`
+
+**6.** To get the link(s), enter
+```bash
+curl -s http://127.0.0.1:9091/v1/users | jq
+```
+
+> Any number of people can use one link.
+
+---
+
+# Telemt via Docker Compose
+
+**1. Edit `config.toml` in repo root (at least: port, users secrets, tls_domain)**  
+**2. Start container:**
+```bash
+docker compose up -d --build
+```
+**3. Check logs:**
+```bash
+docker compose logs -f telemt
+```
+**4. Stop:**
+```bash
+docker compose down
+```
+> [!NOTE]
+> - `docker-compose.yml` maps `./config.toml` to `/app/config.toml` (read-only)
+> - By default it publishes `443:443` and runs with dropped capabilities (only `NET_BIND_SERVICE` is added)
+> - If you really need host networking (usually only for some IPv6 setups) uncomment `network_mode: host`
+
+**Run without Compose**
+```bash
+docker build -t telemt:local .
+docker run --name telemt --restart unless-stopped \
+  -p 443:443 \
+  -e RUST_LOG=info \
+  -v "$PWD/config.toml:/app/config.toml:ro" \
+  --read-only \
+  --cap-drop ALL --cap-add NET_BIND_SERVICE \
+  --ulimit nofile=65536:65536 \
+  telemt:local
+```

docs/QUICK_START_GUIDE.ru.md

@@ -0,0 +1,167 @@
+# Telemt через Systemd
+
+## Установка
+
+Это программное обеспечение разработано для ОС на базе Debian: помимо Debian, это Ubuntu, Mint, Kali, MX и многие другие Linux
+
+**1. Скачать**
+```bash
+wget -qO- "https://github.com/telemt/telemt/releases/latest/download/telemt-$(uname -m)-linux-$(ldd --version 2>&1 | grep -iq musl && echo musl || echo gnu).tar.gz" | tar -xz
+```
+**2. Переместить в папку Bin**
+```bash
+mv telemt /bin
+```
+**3. Сделать файл исполняемым**
+```bash
+chmod +x /bin/telemt
+```
+
+## Как правильно использовать?
+
+**Эта инструкция "предполагает", что вы:**
+- Авторизовались как пользователь root или выполнил `su -` / `sudo su`
+- У вас уже есть исполняемый файл "telemt" в папке /bin. Читайте раздел **[Установка](#установка)**
+
+---
+
+**0. Проверьте порт и сгенерируйте секреты**
+
+Порт, который вы выбрали для использования, должен отсутствовать в списке:
+```bash
+netstat -lnp
+```
+
+Сгенерируйте 16 bytes/32 символа в шестнадцатеричном формате с помощью OpenSSL или другим способом:
+```bash
+openssl rand -hex 16
+```
+ИЛИ
+```bash
+xxd -l 16 -p /dev/urandom
+```
+ИЛИ
+```bash
+python3 -c 'import os; print(os.urandom(16).hex())'
+```
+Полученный результат сохраняем где-нибудь. Он понадобиться вам дальше!
+
+---
+
+**1. Поместите свою конфигурацию в файл /etc/telemt.toml**
+
+Открываем nano
+```bash
+nano /etc/telemt.toml
+```
+Вставьте свою конфигурацию
+
+```toml
+# === General Settings ===
+[general]
+# ad_tag = "00000000000000000000000000000000"
+use_middle_proxy = false
+
+[general.modes]
+classic = false
+secure = false
+tls = true
+
+[server.api]
+enabled = true
+# listen = "127.0.0.1:9091"
+# whitelist = ["127.0.0.1/32"]
+# read_only = true
+
+# === Anti-Censorship & Masking ===
+[censorship]
+tls_domain = "petrovich.ru"
+
+[access.users]
+# format: "username" = "32_hex_chars_secret"
+hello = "00000000000000000000000000000000"
+```
+
+Затем нажмите Ctrl+S -> Ctrl+X, чтобы сохранить
+
+> [!WARNING]
+> Замените значение параметра hello на значение, которое вы получили в пункте 0.  
+> Так же замените значение параметра tls_domain на другой сайт.
+
+---
+
+**2. Создайте службу в /etc/systemd/system/telemt.service**
+
+Открываем nano
+```bash
+nano /etc/systemd/system/telemt.service
+```
+
+Вставьте этот модуль Systemd
+```bash
+[Unit]
+Description=Telemt
+After=network.target
+
+[Service]
+Type=simple
+WorkingDirectory=/bin
+ExecStart=/bin/telemt /etc/telemt.toml
+Restart=on-failure
+LimitNOFILE=65536
+
+[Install]
+WantedBy=multi-user.target
+```
+Затем нажмите Ctrl+S -> Ctrl+X, чтобы сохранить
+
+
+**3.** Для запуска введите команду `systemctl start telemt`
+
+**4.** Для получения информации о статусе введите `systemctl status telemt`
+
+**5.** Для автоматического запуска при запуске системы в введите `systemctl enable telemt`
+
+**6.** Для получения ссылки/ссылок введите 
+```bash
+curl -s http://127.0.0.1:9091/v1/users | jq
+```
+> Одной ссылкой модет пользоваться сколько угодно человек.
+
+> [!WARNING]
+> Рабочую ссылку может выдать только команда из 6 пункта. Не пытайтесь делать ее самостоятельно или копировать откуда-либо если вы не уверены в том, что делаете!
+
+---
+
+# Telemt через Docker Compose
+
+**1. Отредактируйте `config.toml` в корневом каталоге репозитория (как минимум: порт, пользовательские секреты, tls_domain)**  
+**2. Запустите контейнер:**
+```bash
+docker compose up -d --build
+```
+**3. Проверьте логи:**
+```bash
+docker compose logs -f telemt
+```
+**4. Остановите контейнер:**
+```bash
+docker compose down
+```
+> [!NOTE]
+> - В `docker-compose.yml` файл `./config.toml` монтируется в `/app/config.toml` (доступно только для чтения)  
+> - По умолчанию публикуются порты 443:443, а контейнер запускается со сброшенными привилегиями (добавлена только `NET_BIND_SERVICE`)  
+> - Если вам действительно нужна сеть хоста (обычно это требуется только для некоторых конфигураций IPv6), раскомментируйте `network_mode: host`
+
+**Запуск в Docker Compose**
+```bash
+docker build -t telemt:local .
+docker run --name telemt --restart unless-stopped \
+  -p 443:443 \
+  -e RUST_LOG=info \
+  -v "$PWD/config.toml:/app/config.toml:ro" \
+  --read-only \
+  --cap-drop ALL --cap-add NET_BIND_SERVICE \
+  --ulimit nofile=65536:65536 \
+  telemt:local
+```

docs/TUNING.de.md

@@ -0,0 +1,219 @@
+# Telemt Tuning-Leitfaden: Middle-End und Upstreams
+
+Dieses Dokument beschreibt das aktuelle Laufzeitverhalten für Middle-End (ME) und Upstream-Routing basierend auf:
+- `src/config/types.rs`
+- `src/config/defaults.rs`
+- `src/config/load.rs`
+- `src/transport/upstream.rs`
+
+Die unten angegebenen `Default`-Werte sind Code-Defaults (bei fehlendem Schlüssel), nicht zwingend die Werte aus `config.full.toml`.
+
+## Middle-End-Parameter
+
+### 1) ME-Grundmodus, NAT und STUN
+
+| Parameter | Typ | Default | Einschränkungen / Validierung | Laufzeiteffekt | Beispiel |
+|---|---|---:|---|---|---|
+| `general.use_middle_proxy` | `bool` | `true` | keine | Aktiviert den ME-Transportmodus. Bei `false` wird Direct-Modus verwendet. | `use_middle_proxy = true` |
+| `general.proxy_secret_path` | `Option<String>` | `"proxy-secret"` | Pfad kann `null` sein | Pfad zur Telegram-Infrastrukturdatei `proxy-secret`. | `proxy_secret_path = "proxy-secret"` |
+| `general.middle_proxy_nat_ip` | `Option<IpAddr>` | `null` | gültige IP bei gesetztem Wert | Manueller Override der öffentlichen NAT-IP für ME-Adressmaterial. | `middle_proxy_nat_ip = "203.0.113.10"` |
+| `general.middle_proxy_nat_probe` | `bool` | `true` | wird auf `true` erzwungen, wenn `use_middle_proxy=true` | Aktiviert NAT-Probing für ME. | `middle_proxy_nat_probe = true` |
+| `general.stun_nat_probe_concurrency` | `usize` | `8` | muss `> 0` sein | Maximale parallele STUN-Probes während NAT-Erkennung. | `stun_nat_probe_concurrency = 16` |
+| `network.stun_use` | `bool` | `true` | keine | Globaler STUN-Schalter. Bei `false` wird STUN deaktiviert. | `stun_use = true` |
+| `network.stun_servers` | `Vec<String>` | integrierter öffentlicher Pool | Duplikate/leer werden entfernt | Primäre STUN-Serverliste für NAT/Public-Endpoint-Erkennung. | `stun_servers = ["stun1.l.google.com:19302"]` |
+| `network.stun_tcp_fallback` | `bool` | `true` | keine | Aktiviert TCP-Fallback, wenn UDP-STUN blockiert ist. | `stun_tcp_fallback = true` |
+| `network.http_ip_detect_urls` | `Vec<String>` | `ifconfig.me` + `api.ipify.org` | keine | HTTP-Fallback zur öffentlichen IPv4-Erkennung, falls STUN ausfällt. | `http_ip_detect_urls = ["https://api.ipify.org"]` |
+| `general.stun_iface_mismatch_ignore` | `bool` | `false` | keine | Reserviertes Feld in der aktuellen Revision (derzeit kein aktiver Runtime-Verbrauch). | `stun_iface_mismatch_ignore = false` |
+| `timeouts.me_one_retry` | `u8` | `12` | keine | Anzahl schneller Reconnect-Versuche bei Single-Endpoint-DC-Fällen. | `me_one_retry = 6` |
+| `timeouts.me_one_timeout_ms` | `u64` | `1200` | keine | Timeout pro schnellem Einzelversuch (ms). | `me_one_timeout_ms = 1500` |
+
+### 2) Poolgröße, Keepalive und Reconnect-Policy
+
+| Parameter | Typ | Default | Einschränkungen / Validierung | Laufzeiteffekt | Beispiel |
+|---|---|---:|---|---|---|
+| `general.middle_proxy_pool_size` | `usize` | `8` | keine | Zielgröße des aktiven ME-Writer-Pools. | `middle_proxy_pool_size = 12` |
+| `general.middle_proxy_warm_standby` | `usize` | `16` | keine | Reserviertes Kompatibilitätsfeld in der aktuellen Revision (kein aktiver Runtime-Consumer). | `middle_proxy_warm_standby = 16` |
+| `general.me_keepalive_enabled` | `bool` | `true` | keine | Aktiviert periodischen ME-Keepalive/Ping-Traffic. | `me_keepalive_enabled = true` |
+| `general.me_keepalive_interval_secs` | `u64` | `25` | keine | Basisintervall für Keepalive (Sekunden). | `me_keepalive_interval_secs = 20` |
+| `general.me_keepalive_jitter_secs` | `u64` | `5` | keine | Keepalive-Jitter zur Vermeidung synchroner Peaks. | `me_keepalive_jitter_secs = 3` |
+| `general.me_keepalive_payload_random` | `bool` | `true` | keine | Randomisiert Keepalive-Payload-Bytes. | `me_keepalive_payload_random = true` |
+| `general.me_warmup_stagger_enabled` | `bool` | `true` | keine | Aktiviert gestaffeltes Warmup zusätzlicher ME-Verbindungen. | `me_warmup_stagger_enabled = true` |
+| `general.me_warmup_step_delay_ms` | `u64` | `500` | keine | Basisverzögerung zwischen Warmup-Schritten (ms). | `me_warmup_step_delay_ms = 300` |
+| `general.me_warmup_step_jitter_ms` | `u64` | `300` | keine | Zusätzlicher zufälliger Warmup-Jitter (ms). | `me_warmup_step_jitter_ms = 200` |
+| `general.me_reconnect_max_concurrent_per_dc` | `u32` | `8` | keine | Begrenzung paralleler Reconnect-Worker pro DC. | `me_reconnect_max_concurrent_per_dc = 12` |
+| `general.me_reconnect_backoff_base_ms` | `u64` | `500` | keine | Initiales Reconnect-Backoff (ms). | `me_reconnect_backoff_base_ms = 250` |
+| `general.me_reconnect_backoff_cap_ms` | `u64` | `30000` | keine | Maximales Reconnect-Backoff (ms). | `me_reconnect_backoff_cap_ms = 10000` |
+| `general.me_reconnect_fast_retry_count` | `u32` | `16` | keine | Budget für Sofort-Retries vor längerem Backoff. | `me_reconnect_fast_retry_count = 8` |
+
+### 3) Reinit/Hardswap, Secret-Rotation und Degradation
+
+| Parameter | Typ | Default | Einschränkungen / Validierung | Laufzeiteffekt | Beispiel |
+|---|---|---:|---|---|---|
+| `general.hardswap` | `bool` | `true` | keine | Aktiviert generation-basierte Hardswap-Strategie für den ME-Pool. | `hardswap = true` |
+| `general.me_reinit_every_secs` | `u64` | `900` | muss `> 0` sein | Intervall für periodische ME-Reinitialisierung. | `me_reinit_every_secs = 600` |
+| `general.me_hardswap_warmup_delay_min_ms` | `u64` | `1000` | muss `<= me_hardswap_warmup_delay_max_ms` sein | Untere Grenze für Warmup-Dial-Abstände. | `me_hardswap_warmup_delay_min_ms = 500` |
+| `general.me_hardswap_warmup_delay_max_ms` | `u64` | `2000` | muss `> 0` sein | Obere Grenze für Warmup-Dial-Abstände. | `me_hardswap_warmup_delay_max_ms = 1200` |
+| `general.me_hardswap_warmup_extra_passes` | `u8` | `3` | Bereich `[0,10]` | Zusätzliche Warmup-Pässe nach dem Basispass. | `me_hardswap_warmup_extra_passes = 2` |
+| `general.me_hardswap_warmup_pass_backoff_base_ms` | `u64` | `500` | muss `> 0` sein | Basis-Backoff zwischen zusätzlichen Warmup-Pässen. | `me_hardswap_warmup_pass_backoff_base_ms = 400` |
+| `general.me_config_stable_snapshots` | `u8` | `2` | muss `> 0` sein | Anzahl identischer ME-Config-Snapshots vor Apply. | `me_config_stable_snapshots = 3` |
+| `general.me_config_apply_cooldown_secs` | `u64` | `300` | keine | Cooldown zwischen angewendeten ME-Map-Updates. | `me_config_apply_cooldown_secs = 120` |
+| `general.proxy_secret_stable_snapshots` | `u8` | `2` | muss `> 0` sein | Anzahl identischer Secret-Snapshots vor Rotation. | `proxy_secret_stable_snapshots = 3` |
+| `general.proxy_secret_rotate_runtime` | `bool` | `true` | keine | Aktiviert Runtime-Rotation des Proxy-Secrets. | `proxy_secret_rotate_runtime = true` |
+| `general.proxy_secret_len_max` | `usize` | `256` | Bereich `[32,4096]` | Obergrenze für akzeptierte Secret-Länge. | `proxy_secret_len_max = 512` |
+| `general.update_every` | `Option<u64>` | `300` | wenn gesetzt: `> 0`; bei `null`: Legacy-Min-Fallback | Einheitliches Refresh-Intervall für ME-Config + Secret-Updater. | `update_every = 300` |
+| `general.me_pool_drain_ttl_secs` | `u64` | `90` | keine | Zeitraum, in dem stale Writer noch als Fallback zulässig sind. | `me_pool_drain_ttl_secs = 120` |
+| `general.me_pool_min_fresh_ratio` | `f32` | `0.8` | Bereich `[0.0,1.0]` | Coverage-Schwelle vor Drain der alten Generation. | `me_pool_min_fresh_ratio = 0.9` |
+| `general.me_reinit_drain_timeout_secs` | `u64` | `120` | `0` = kein Force-Close; wenn `>0 && < TTL`, dann auf TTL angehoben | Force-Close-Timeout für draining stale Writer. | `me_reinit_drain_timeout_secs = 0` |
+| `general.auto_degradation_enabled` | `bool` | `true` | keine | Reserviertes Kompatibilitätsfeld in aktueller Revision (kein aktiver Runtime-Consumer). | `auto_degradation_enabled = true` |
+| `general.degradation_min_unavailable_dc_groups` | `u8` | `2` | keine | Reservierter Kompatibilitäts-Schwellenwert in aktueller Revision (kein aktiver Runtime-Consumer). | `degradation_min_unavailable_dc_groups = 2` |
+
+## Deprecated / Legacy Parameter
+
+| Parameter | Status | Ersatz | Aktuelles Verhalten | Migrationshinweis |
+|---|---|---|---|---|
+| `general.middle_proxy_nat_stun` | Deprecated | `network.stun_servers` | Wird nur dann in `network.stun_servers` gemerged, wenn `network.stun_servers` nicht explizit gesetzt ist. | Wert nach `network.stun_servers` verschieben, Legacy-Key entfernen. |
+| `general.middle_proxy_nat_stun_servers` | Deprecated | `network.stun_servers` | Wird nur dann in `network.stun_servers` gemerged, wenn `network.stun_servers` nicht explizit gesetzt ist. | Werte nach `network.stun_servers` verschieben, Legacy-Key entfernen. |
+| `general.proxy_secret_auto_reload_secs` | Deprecated | `general.update_every` | Nur aktiv, wenn `update_every = null` (Legacy-Fallback). | `general.update_every` explizit setzen, Legacy-Key entfernen. |
+| `general.proxy_config_auto_reload_secs` | Deprecated | `general.update_every` | Nur aktiv, wenn `update_every = null` (Legacy-Fallback). | `general.update_every` explizit setzen, Legacy-Key entfernen. |
+
+## Wie Upstreams konfiguriert werden
+
+### Upstream-Schema
+
+| Feld | Gilt für | Typ | Pflicht | Default | Bedeutung |
+|---|---|---|---|---|---|
+| `[[upstreams]].type` | alle Upstreams | `"direct" \| "socks4" \| "socks5"` | ja | n/a | Upstream-Transporttyp. |
+| `[[upstreams]].weight` | alle Upstreams | `u16` | nein | `1` | Basisgewicht für weighted-random Auswahl. |
+| `[[upstreams]].enabled` | alle Upstreams | `bool` | nein | `true` | Deaktivierte Einträge werden beim Start ignoriert. |
+| `[[upstreams]].scopes` | alle Upstreams | `String` | nein | `""` | Komma-separierte Scope-Tags für Request-Routing. |
+| `interface` | `direct` | `Option<String>` | nein | `null` | Interface-Name (z. B. `eth0`) oder lokale Literal-IP. |
+| `bind_addresses` | `direct` | `Option<Vec<IpAddr>>` | nein | `null` | Explizite Source-IP-Kandidaten (strikter Vorrang vor `interface`). |
+| `address` | `socks4` | `String` | ja | n/a | SOCKS4-Server (`ip:port` oder `host:port`). |
+| `interface` | `socks4` | `Option<String>` | nein | `null` | Wird nur genutzt, wenn `address` als `ip:port` angegeben ist. |
+| `user_id` | `socks4` | `Option<String>` | nein | `null` | SOCKS4 User-ID für CONNECT. |
+| `address` | `socks5` | `String` | ja | n/a | SOCKS5-Server (`ip:port` oder `host:port`). |
+| `interface` | `socks5` | `Option<String>` | nein | `null` | Wird nur genutzt, wenn `address` als `ip:port` angegeben ist. |
+| `username` | `socks5` | `Option<String>` | nein | `null` | SOCKS5 Benutzername. |
+| `password` | `socks5` | `Option<String>` | nein | `null` | SOCKS5 Passwort. |
+
+### Runtime-Regeln (wichtig)
+
+1. Wenn `[[upstreams]]` fehlt, injiziert der Loader einen Default-`direct`-Upstream.
+2. Scope-Filterung basiert auf exaktem Token-Match:
+- mit Request-Scope -> nur Einträge, deren `scopes` genau dieses Token enthält;
+- ohne Request-Scope -> nur Einträge mit leerem `scopes`.
+3. Unter healthy Upstreams erfolgt die Auswahl per weighted random: `weight * latency_factor`.
+4. Gibt es im gefilterten Set keinen healthy Upstream, wird zufällig aus dem gefilterten Set gewählt.
+5. `direct`-Bind-Auflösung:
+- zuerst `bind_addresses` (nur gleiche IP-Familie wie Target);
+- bei `interface` (Name) + `bind_addresses` wird jede Candidate-IP gegen Interface-Adressen validiert;
+- ungültige Kandidaten werden mit `WARN` verworfen;
+- bleiben keine gültigen Kandidaten übrig, erfolgt unbound direct connect (`bind_ip=None`);
+- wenn `bind_addresses` nicht passt, wird `interface` verwendet (Literal-IP oder Interface-Primäradresse).
+6. Für `socks4/socks5` mit Hostname-`address` ist Interface-Binding nicht unterstützt und wird mit Warnung ignoriert.
+7. Runtime DNS Overrides werden für Hostname-Auflösung bei Upstream-Verbindungen genutzt.
+8. Im ME-Modus wird der gewählte Upstream auch für den ME-TCP-Dial-Pfad verwendet.
+9. Im ME-Modus ist bei `direct` mit bind/interface die STUN-Reflection bind-aware für KDF-Adressmaterial.
+10. Im ME-Modus werden bei SOCKS-Upstream `BND.ADDR/BND.PORT` für KDF verwendet, wenn gültig/öffentlich und gleiche IP-Familie.
+
+## Upstream-Konfigurationsbeispiele
+
+### Beispiel 1: Minimaler direct Upstream
+
+```toml
+[[upstreams]]
+type = "direct"
+weight = 1
+enabled = true
+```
+
+### Beispiel 2: direct mit Interface + expliziten bind IPs
+
+```toml
+[[upstreams]]
+type = "direct"
+interface = "eth0"
+bind_addresses = ["192.168.1.100", "192.168.1.101"]
+weight = 3
+enabled = true
+```
+
+### Beispiel 3: SOCKS5 Upstream mit Authentifizierung
+
+```toml
+[[upstreams]]
+type = "socks5"
+address = "198.51.100.30:1080"
+username = "proxy-user"
+password = "proxy-pass"
+weight = 2
+enabled = true
+```
+
+### Beispiel 4: Gemischte Upstreams mit Scopes
+
+```toml
+[[upstreams]]
+type = "direct"
+weight = 5
+enabled = true
+scopes = ""
+
+[[upstreams]]
+type = "socks5"
+address = "203.0.113.40:1080"
+username = "edge"
+password = "edgepass"
+weight = 3
+enabled = true
+scopes = "premium,me"
+```
+
+### Beispiel 5: ME-orientiertes Tuning-Profil
+
+```toml
+[general]
+use_middle_proxy = true
+proxy_secret_path = "proxy-secret"
+middle_proxy_nat_probe = true
+stun_nat_probe_concurrency = 16
+middle_proxy_pool_size = 12
+me_keepalive_enabled = true
+me_keepalive_interval_secs = 20
+me_keepalive_jitter_secs = 4
+me_reconnect_max_concurrent_per_dc = 12
+me_reconnect_backoff_base_ms = 300
+me_reconnect_backoff_cap_ms = 10000
+me_reconnect_fast_retry_count = 10
+hardswap = true
+me_reinit_every_secs = 600
+me_hardswap_warmup_delay_min_ms = 500
+me_hardswap_warmup_delay_max_ms = 1200
+me_hardswap_warmup_extra_passes = 2
+me_hardswap_warmup_pass_backoff_base_ms = 400
+me_config_stable_snapshots = 3
+me_config_apply_cooldown_secs = 120
+proxy_secret_stable_snapshots = 3
+proxy_secret_rotate_runtime = true
+proxy_secret_len_max = 512
+update_every = 300
+me_pool_drain_ttl_secs = 120
+me_pool_min_fresh_ratio = 0.9
+me_reinit_drain_timeout_secs = 180
+
+[timeouts]
+me_one_retry = 8
+me_one_timeout_ms = 1200
+
+[network]
+stun_use = true
+stun_tcp_fallback = true
+stun_servers = [
+  "stun1.l.google.com:19302",
+  "stun2.l.google.com:19302"
+]
+http_ip_detect_urls = [
+  "https://api.ipify.org",
+  "https://ifconfig.me/ip"
+]
+```

docs/TUNING.en.md

@@ -0,0 +1,219 @@
+# Telemt Tuning Guide: Middle-End and Upstreams
+
+This document describes the current runtime behavior for Middle-End (ME) and upstream routing based on:
+- `src/config/types.rs`
+- `src/config/defaults.rs`
+- `src/config/load.rs`
+- `src/transport/upstream.rs`
+
+Defaults below are code defaults (used when a key is omitted), not necessarily values from `config.full.toml` examples.
+
+## Middle-End Parameters
+
+### 1) Core ME mode, NAT, and STUN
+
+| Parameter | Type | Default | Constraints / validation | Runtime effect | Example |
+|---|---|---:|---|---|---|
+| `general.use_middle_proxy` | `bool` | `true` | none | Enables ME transport mode. If `false`, Direct mode is used. | `use_middle_proxy = true` |
+| `general.proxy_secret_path` | `Option<String>` | `"proxy-secret"` | path may be `null` | Path to Telegram infrastructure proxy-secret file. | `proxy_secret_path = "proxy-secret"` |
+| `general.middle_proxy_nat_ip` | `Option<IpAddr>` | `null` | valid IP when set | Manual public NAT IP override for ME address material. | `middle_proxy_nat_ip = "203.0.113.10"` |
+| `general.middle_proxy_nat_probe` | `bool` | `true` | auto-forced to `true` when `use_middle_proxy=true` | Enables ME NAT probing. | `middle_proxy_nat_probe = true` |
+| `general.stun_nat_probe_concurrency` | `usize` | `8` | must be `> 0` | Max parallel STUN probes during NAT discovery. | `stun_nat_probe_concurrency = 16` |
+| `network.stun_use` | `bool` | `true` | none | Global STUN switch. If `false`, STUN probing is disabled. | `stun_use = true` |
+| `network.stun_servers` | `Vec<String>` | built-in public pool | deduplicated + empty values removed | Primary STUN server list for NAT/public endpoint discovery. | `stun_servers = ["stun1.l.google.com:19302"]` |
+| `network.stun_tcp_fallback` | `bool` | `true` | none | Enables TCP fallback path when UDP STUN is blocked. | `stun_tcp_fallback = true` |
+| `network.http_ip_detect_urls` | `Vec<String>` | `ifconfig.me` + `api.ipify.org` | none | HTTP fallback for public IPv4 detection if STUN is unavailable. | `http_ip_detect_urls = ["https://api.ipify.org"]` |
+| `general.stun_iface_mismatch_ignore` | `bool` | `false` | none | Reserved flag in current revision (not consumed by runtime path). | `stun_iface_mismatch_ignore = false` |
+| `timeouts.me_one_retry` | `u8` | `12` | none | Fast reconnect attempts for single-endpoint DC cases. | `me_one_retry = 6` |
+| `timeouts.me_one_timeout_ms` | `u64` | `1200` | none | Timeout per quick single-endpoint attempt (ms). | `me_one_timeout_ms = 1500` |
+
+### 2) Pool size, keepalive, and reconnect policy
+
+| Parameter | Type | Default | Constraints / validation | Runtime effect | Example |
+|---|---|---:|---|---|---|
+| `general.middle_proxy_pool_size` | `usize` | `8` | none | Target active ME writer pool size. | `middle_proxy_pool_size = 12` |
+| `general.middle_proxy_warm_standby` | `usize` | `16` | none | Reserved compatibility field in current revision (no active runtime consumer). | `middle_proxy_warm_standby = 16` |
+| `general.me_keepalive_enabled` | `bool` | `true` | none | Enables periodic ME keepalive/ping traffic. | `me_keepalive_enabled = true` |
+| `general.me_keepalive_interval_secs` | `u64` | `25` | none | Base keepalive interval (seconds). | `me_keepalive_interval_secs = 20` |
+| `general.me_keepalive_jitter_secs` | `u64` | `5` | none | Keepalive jitter to avoid synchronization bursts. | `me_keepalive_jitter_secs = 3` |
+| `general.me_keepalive_payload_random` | `bool` | `true` | none | Randomizes keepalive payload bytes. | `me_keepalive_payload_random = true` |
+| `general.me_warmup_stagger_enabled` | `bool` | `true` | none | Staggers extra ME warmup dials to avoid spikes. | `me_warmup_stagger_enabled = true` |
+| `general.me_warmup_step_delay_ms` | `u64` | `500` | none | Base delay between warmup dial steps (ms). | `me_warmup_step_delay_ms = 300` |
+| `general.me_warmup_step_jitter_ms` | `u64` | `300` | none | Additional random delay for warmup steps (ms). | `me_warmup_step_jitter_ms = 200` |
+| `general.me_reconnect_max_concurrent_per_dc` | `u32` | `8` | none | Limits concurrent reconnect workers per DC in health recovery. | `me_reconnect_max_concurrent_per_dc = 12` |
+| `general.me_reconnect_backoff_base_ms` | `u64` | `500` | none | Initial reconnect backoff (ms). | `me_reconnect_backoff_base_ms = 250` |
+| `general.me_reconnect_backoff_cap_ms` | `u64` | `30000` | none | Maximum reconnect backoff (ms). | `me_reconnect_backoff_cap_ms = 10000` |
+| `general.me_reconnect_fast_retry_count` | `u32` | `16` | none | Immediate retry budget before long backoff behavior. | `me_reconnect_fast_retry_count = 8` |
+
+### 3) Reinit/hardswap, secret rotation, and degradation
+
+| Parameter | Type | Default | Constraints / validation | Runtime effect | Example |
+|---|---|---:|---|---|---|
+| `general.hardswap` | `bool` | `true` | none | Enables generation-based ME hardswap strategy. | `hardswap = true` |
+| `general.me_reinit_every_secs` | `u64` | `900` | must be `> 0` | Periodic ME reinit interval. | `me_reinit_every_secs = 600` |
+| `general.me_hardswap_warmup_delay_min_ms` | `u64` | `1000` | must be `<= me_hardswap_warmup_delay_max_ms` | Lower bound for hardswap warmup dial spacing. | `me_hardswap_warmup_delay_min_ms = 500` |
+| `general.me_hardswap_warmup_delay_max_ms` | `u64` | `2000` | must be `> 0` | Upper bound for hardswap warmup dial spacing. | `me_hardswap_warmup_delay_max_ms = 1200` |
+| `general.me_hardswap_warmup_extra_passes` | `u8` | `3` | must be within `[0,10]` | Additional warmup passes after base pass. | `me_hardswap_warmup_extra_passes = 2` |
+| `general.me_hardswap_warmup_pass_backoff_base_ms` | `u64` | `500` | must be `> 0` | Base backoff between extra warmup passes. | `me_hardswap_warmup_pass_backoff_base_ms = 400` |
+| `general.me_config_stable_snapshots` | `u8` | `2` | must be `> 0` | Number of identical ME config snapshots required before apply. | `me_config_stable_snapshots = 3` |
+| `general.me_config_apply_cooldown_secs` | `u64` | `300` | none | Cooldown between applied ME map updates. | `me_config_apply_cooldown_secs = 120` |
+| `general.proxy_secret_stable_snapshots` | `u8` | `2` | must be `> 0` | Number of identical proxy-secret snapshots required before rotation. | `proxy_secret_stable_snapshots = 3` |
+| `general.proxy_secret_rotate_runtime` | `bool` | `true` | none | Enables runtime proxy-secret rotation. | `proxy_secret_rotate_runtime = true` |
+| `general.proxy_secret_len_max` | `usize` | `256` | must be within `[32,4096]` | Upper limit for accepted proxy-secret length. | `proxy_secret_len_max = 512` |
+| `general.update_every` | `Option<u64>` | `300` | if set: must be `> 0`; if `null`: legacy min fallback | Unified refresh interval for ME config + secret updater. | `update_every = 300` |
+| `general.me_pool_drain_ttl_secs` | `u64` | `90` | none | Time window where stale writers remain fallback-eligible. | `me_pool_drain_ttl_secs = 120` |
+| `general.me_pool_min_fresh_ratio` | `f32` | `0.8` | must be within `[0.0,1.0]` | Coverage threshold before stale generation can be drained. | `me_pool_min_fresh_ratio = 0.9` |
+| `general.me_reinit_drain_timeout_secs` | `u64` | `120` | `0` means no force-close; if `>0 && < TTL` it is bumped to TTL | Force-close timeout for draining stale writers. | `me_reinit_drain_timeout_secs = 0` |
+| `general.auto_degradation_enabled` | `bool` | `true` | none | Reserved compatibility flag in current revision (no active runtime consumer). | `auto_degradation_enabled = true` |
+| `general.degradation_min_unavailable_dc_groups` | `u8` | `2` | none | Reserved compatibility threshold in current revision (no active runtime consumer). | `degradation_min_unavailable_dc_groups = 2` |
+
+## Deprecated / Legacy Parameters
+
+| Parameter | Status | Replacement | Current behavior | Migration recommendation |
+|---|---|---|---|---|
+| `general.middle_proxy_nat_stun` | Deprecated | `network.stun_servers` | Merged into `network.stun_servers` only when `network.stun_servers` is not explicitly set. | Move value into `network.stun_servers` and remove legacy key. |
+| `general.middle_proxy_nat_stun_servers` | Deprecated | `network.stun_servers` | Merged into `network.stun_servers` only when `network.stun_servers` is not explicitly set. | Move values into `network.stun_servers` and remove legacy key. |
+| `general.proxy_secret_auto_reload_secs` | Deprecated | `general.update_every` | Used only when `update_every = null` (legacy fallback path). | Set `general.update_every` explicitly and remove legacy key. |
+| `general.proxy_config_auto_reload_secs` | Deprecated | `general.update_every` | Used only when `update_every = null` (legacy fallback path). | Set `general.update_every` explicitly and remove legacy key. |
+
+## How Upstreams Are Configured
+
+### Upstream schema
+
+| Field | Applies to | Type | Required | Default | Meaning |
+|---|---|---|---|---|---|
+| `[[upstreams]].type` | all upstreams | `"direct" \| "socks4" \| "socks5"` | yes | n/a | Upstream transport type. |
+| `[[upstreams]].weight` | all upstreams | `u16` | no | `1` | Base weight for weighted-random selection. |
+| `[[upstreams]].enabled` | all upstreams | `bool` | no | `true` | Disabled entries are ignored at startup. |
+| `[[upstreams]].scopes` | all upstreams | `String` | no | `""` | Comma-separated scope tags for request-level routing. |
+| `interface` | `direct` | `Option<String>` | no | `null` | Interface name (e.g. `eth0`) or literal local IP for bind selection. |
+| `bind_addresses` | `direct` | `Option<Vec<IpAddr>>` | no | `null` | Explicit local source IP candidates (strict priority over `interface`). |
+| `address` | `socks4` | `String` | yes | n/a | SOCKS4 server endpoint (`ip:port` or `host:port`). |
+| `interface` | `socks4` | `Option<String>` | no | `null` | Used only for SOCKS server `ip:port` dial path. |
+| `user_id` | `socks4` | `Option<String>` | no | `null` | SOCKS4 user ID for CONNECT request. |
+| `address` | `socks5` | `String` | yes | n/a | SOCKS5 server endpoint (`ip:port` or `host:port`). |
+| `interface` | `socks5` | `Option<String>` | no | `null` | Used only for SOCKS server `ip:port` dial path. |
+| `username` | `socks5` | `Option<String>` | no | `null` | SOCKS5 username auth. |
+| `password` | `socks5` | `Option<String>` | no | `null` | SOCKS5 password auth. |
+
+### Runtime rules (important)
+
+1. If `[[upstreams]]` is omitted, loader injects one default `direct` upstream.
+2. Scope filtering is exact-token based:
+- when request scope is set -> only entries whose `scopes` contains that exact token;
+- when request scope is not set -> only entries with empty `scopes`.
+3. Healthy upstreams are selected by weighted random using: `weight * latency_factor`.
+4. If no healthy upstream exists in filtered set, random selection is used among filtered entries.
+5. `direct` bind resolution order:
+- `bind_addresses` candidates (same IP family as target) first;
+- if `interface` is an interface name and `bind_addresses` is set, each candidate IP is validated against addresses currently assigned to that interface;
+- invalid candidates are dropped with `WARN`;
+- if no valid candidate remains, connection falls back to unbound direct connect (`bind_ip=None`);
+- if no `bind_addresses` candidate, `interface` is used (literal IP or resolved interface primary IP).
+6. For `socks4/socks5` with `address` as hostname, interface binding is not supported and is ignored with warning.
+7. Runtime DNS overrides are used for upstream hostname resolution.
+8. In ME mode, the selected upstream is also used for ME TCP dial path.
+9. In ME mode for `direct` upstream with bind/interface, STUN reflection logic is bind-aware for KDF source material.
+10. In ME mode for SOCKS upstream, SOCKS `BND.ADDR/BND.PORT` is used for KDF when it is valid/public for the same family.
+
+## Upstream Configuration Examples
+
+### Example 1: Minimal direct upstream
+
+```toml
+[[upstreams]]
+type = "direct"
+weight = 1
+enabled = true
+```
+
+### Example 2: Direct with interface + explicit bind addresses
+
+```toml
+[[upstreams]]
+type = "direct"
+interface = "eth0"
+bind_addresses = ["192.168.1.100", "192.168.1.101"]
+weight = 3
+enabled = true
+```
+
+### Example 3: SOCKS5 upstream with authentication
+
+```toml
+[[upstreams]]
+type = "socks5"
+address = "198.51.100.30:1080"
+username = "proxy-user"
+password = "proxy-pass"
+weight = 2
+enabled = true
+```
+
+### Example 4: Mixed upstreams with scopes
+
+```toml
+[[upstreams]]
+type = "direct"
+weight = 5
+enabled = true
+scopes = ""
+
+[[upstreams]]
+type = "socks5"
+address = "203.0.113.40:1080"
+username = "edge"
+password = "edgepass"
+weight = 3
+enabled = true
+scopes = "premium,me"
+```
+
+### Example 5: ME-focused tuning profile
+
+```toml
+[general]
+use_middle_proxy = true
+proxy_secret_path = "proxy-secret"
+middle_proxy_nat_probe = true
+stun_nat_probe_concurrency = 16
+middle_proxy_pool_size = 12
+me_keepalive_enabled = true
+me_keepalive_interval_secs = 20
+me_keepalive_jitter_secs = 4
+me_reconnect_max_concurrent_per_dc = 12
+me_reconnect_backoff_base_ms = 300
+me_reconnect_backoff_cap_ms = 10000
+me_reconnect_fast_retry_count = 10
+hardswap = true
+me_reinit_every_secs = 600
+me_hardswap_warmup_delay_min_ms = 500
+me_hardswap_warmup_delay_max_ms = 1200
+me_hardswap_warmup_extra_passes = 2
+me_hardswap_warmup_pass_backoff_base_ms = 400
+me_config_stable_snapshots = 3
+me_config_apply_cooldown_secs = 120
+proxy_secret_stable_snapshots = 3
+proxy_secret_rotate_runtime = true
+proxy_secret_len_max = 512
+update_every = 300
+me_pool_drain_ttl_secs = 120
+me_pool_min_fresh_ratio = 0.9
+me_reinit_drain_timeout_secs = 180
+
+[timeouts]
+me_one_retry = 8
+me_one_timeout_ms = 1200
+
+[network]
+stun_use = true
+stun_tcp_fallback = true
+stun_servers = [
+  "stun1.l.google.com:19302",
+  "stun2.l.google.com:19302"
+]
+http_ip_detect_urls = [
+  "https://api.ipify.org",
+  "https://ifconfig.me/ip"
+]
+```

docs/TUNING.ru.md

@@ -0,0 +1,219 @@
+# Руководство по тюнингу Telemt: Middle-End и Upstreams
+
+Документ описывает актуальное поведение Middle-End (ME) и маршрутизации через upstream на основе:
+- `src/config/types.rs`
+- `src/config/defaults.rs`
+- `src/config/load.rs`
+- `src/transport/upstream.rs`
+
+Значения `Default` ниже — это значения из кода при отсутствии ключа в конфиге, а не обязательно значения из примеров `config.full.toml`.
+
+## Параметры Middle-End
+
+### 1) Базовый режим ME, NAT и STUN
+
+| Параметр | Тип | Default | Ограничения / валидация | Влияние на runtime | Пример |
+|---|---|---:|---|---|---|
+| `general.use_middle_proxy` | `bool` | `true` | нет | Включает транспорт ME. При `false` используется Direct-режим. | `use_middle_proxy = true` |
+| `general.proxy_secret_path` | `Option<String>` | `"proxy-secret"` | путь может быть `null` | Путь к инфраструктурному proxy-secret Telegram. | `proxy_secret_path = "proxy-secret"` |
+| `general.middle_proxy_nat_ip` | `Option<IpAddr>` | `null` | валидный IP при задании | Ручной override публичного NAT IP для адресного материала ME. | `middle_proxy_nat_ip = "203.0.113.10"` |
+| `general.middle_proxy_nat_probe` | `bool` | `true` | авто-принудительно `true`, если `use_middle_proxy=true` | Включает NAT probing для ME. | `middle_proxy_nat_probe = true` |
+| `general.stun_nat_probe_concurrency` | `usize` | `8` | должно быть `> 0` | Максимум параллельных STUN-проб при NAT-детекте. | `stun_nat_probe_concurrency = 16` |
+| `network.stun_use` | `bool` | `true` | нет | Глобальный переключатель STUN. При `false` STUN отключен. | `stun_use = true` |
+| `network.stun_servers` | `Vec<String>` | встроенный публичный пул | удаляются дубликаты и пустые значения | Основной список STUN-серверов для NAT/public endpoint discovery. | `stun_servers = ["stun1.l.google.com:19302"]` |
+| `network.stun_tcp_fallback` | `bool` | `true` | нет | Включает TCP fallback, если UDP STUN недоступен. | `stun_tcp_fallback = true` |
+| `network.http_ip_detect_urls` | `Vec<String>` | `ifconfig.me` + `api.ipify.org` | нет | HTTP fallback для определения публичного IPv4 при недоступности STUN. | `http_ip_detect_urls = ["https://api.ipify.org"]` |
+| `general.stun_iface_mismatch_ignore` | `bool` | `false` | нет | Зарезервированный флаг в текущей ревизии (runtime его не использует). | `stun_iface_mismatch_ignore = false` |
+| `timeouts.me_one_retry` | `u8` | `12` | нет | Количество быстрых reconnect-попыток для DC с одним endpoint. | `me_one_retry = 6` |
+| `timeouts.me_one_timeout_ms` | `u64` | `1200` | нет | Таймаут одной быстрой попытки (мс). | `me_one_timeout_ms = 1500` |
+
+### 2) Размер пула, keepalive и reconnect-политика
+
+| Параметр | Тип | Default | Ограничения / валидация | Влияние на runtime | Пример |
+|---|---|---:|---|---|---|
+| `general.middle_proxy_pool_size` | `usize` | `8` | нет | Целевой размер активного пула ME-writer соединений. | `middle_proxy_pool_size = 12` |
+| `general.middle_proxy_warm_standby` | `usize` | `16` | нет | Зарезервированное поле совместимости в текущей ревизии (активного runtime-consumer нет). | `middle_proxy_warm_standby = 16` |
+| `general.me_keepalive_enabled` | `bool` | `true` | нет | Включает периодические keepalive/ping кадры ME. | `me_keepalive_enabled = true` |
+| `general.me_keepalive_interval_secs` | `u64` | `25` | нет | Базовый интервал keepalive (сек). | `me_keepalive_interval_secs = 20` |
+| `general.me_keepalive_jitter_secs` | `u64` | `5` | нет | Джиттер keepalive для предотвращения синхронных всплесков. | `me_keepalive_jitter_secs = 3` |
+| `general.me_keepalive_payload_random` | `bool` | `true` | нет | Рандомизирует payload keepalive-кадров. | `me_keepalive_payload_random = true` |
+| `general.me_warmup_stagger_enabled` | `bool` | `true` | нет | Включает staggered warmup дополнительных ME-коннектов. | `me_warmup_stagger_enabled = true` |
+| `general.me_warmup_step_delay_ms` | `u64` | `500` | нет | Базовая задержка между шагами warmup (мс). | `me_warmup_step_delay_ms = 300` |
+| `general.me_warmup_step_jitter_ms` | `u64` | `300` | нет | Дополнительный случайный warmup-джиттер (мс). | `me_warmup_step_jitter_ms = 200` |
+| `general.me_reconnect_max_concurrent_per_dc` | `u32` | `8` | нет | Ограничивает параллельные reconnect worker'ы на один DC. | `me_reconnect_max_concurrent_per_dc = 12` |
+| `general.me_reconnect_backoff_base_ms` | `u64` | `500` | нет | Начальный backoff reconnect (мс). | `me_reconnect_backoff_base_ms = 250` |
+| `general.me_reconnect_backoff_cap_ms` | `u64` | `30000` | нет | Верхняя граница backoff reconnect (мс). | `me_reconnect_backoff_cap_ms = 10000` |
+| `general.me_reconnect_fast_retry_count` | `u32` | `16` | нет | Бюджет быстрых retry до длинного backoff. | `me_reconnect_fast_retry_count = 8` |
+
+### 3) Reinit/hardswap, ротация секрета и деградация
+
+| Параметр | Тип | Default | Ограничения / валидация | Влияние на runtime | Пример |
+|---|---|---:|---|---|---|
+| `general.hardswap` | `bool` | `true` | нет | Включает generation-based стратегию hardswap для ME-пула. | `hardswap = true` |
+| `general.me_reinit_every_secs` | `u64` | `900` | должно быть `> 0` | Интервал периодического reinit ME-пула. | `me_reinit_every_secs = 600` |
+| `general.me_hardswap_warmup_delay_min_ms` | `u64` | `1000` | должно быть `<= me_hardswap_warmup_delay_max_ms` | Нижняя граница пауз между warmup dial попытками. | `me_hardswap_warmup_delay_min_ms = 500` |
+| `general.me_hardswap_warmup_delay_max_ms` | `u64` | `2000` | должно быть `> 0` | Верхняя граница пауз между warmup dial попытками. | `me_hardswap_warmup_delay_max_ms = 1200` |
+| `general.me_hardswap_warmup_extra_passes` | `u8` | `3` | диапазон `[0,10]` | Дополнительные warmup-проходы после базового. | `me_hardswap_warmup_extra_passes = 2` |
+| `general.me_hardswap_warmup_pass_backoff_base_ms` | `u64` | `500` | должно быть `> 0` | Базовый backoff между extra-pass в warmup. | `me_hardswap_warmup_pass_backoff_base_ms = 400` |
+| `general.me_config_stable_snapshots` | `u8` | `2` | должно быть `> 0` | Количество одинаковых snapshot перед применением ME map update. | `me_config_stable_snapshots = 3` |
+| `general.me_config_apply_cooldown_secs` | `u64` | `300` | нет | Cooldown между применёнными обновлениями ME map. | `me_config_apply_cooldown_secs = 120` |
+| `general.proxy_secret_stable_snapshots` | `u8` | `2` | должно быть `> 0` | Количество одинаковых snapshot перед runtime-rotation proxy-secret. | `proxy_secret_stable_snapshots = 3` |
+| `general.proxy_secret_rotate_runtime` | `bool` | `true` | нет | Включает runtime-ротацию proxy-secret. | `proxy_secret_rotate_runtime = true` |
+| `general.proxy_secret_len_max` | `usize` | `256` | диапазон `[32,4096]` | Верхний лимит длины принимаемого proxy-secret. | `proxy_secret_len_max = 512` |
+| `general.update_every` | `Option<u64>` | `300` | если задано: `> 0`; если `null`: fallback на legacy минимум | Единый интервал refresh для ME config + secret updater. | `update_every = 300` |
+| `general.me_pool_drain_ttl_secs` | `u64` | `90` | нет | Время, когда stale writer ещё может использоваться как fallback. | `me_pool_drain_ttl_secs = 120` |
+| `general.me_pool_min_fresh_ratio` | `f32` | `0.8` | диапазон `[0.0,1.0]` | Порог покрытия fresh-поколения перед drain старого поколения. | `me_pool_min_fresh_ratio = 0.9` |
+| `general.me_reinit_drain_timeout_secs` | `u64` | `120` | `0` = без force-close; если `>0 && < TTL`, поднимается до TTL | Таймаут force-close для draining stale writer. | `me_reinit_drain_timeout_secs = 0` |
+| `general.auto_degradation_enabled` | `bool` | `true` | нет | Зарезервированный флаг совместимости в текущей ревизии (активного runtime-consumer нет). | `auto_degradation_enabled = true` |
+| `general.degradation_min_unavailable_dc_groups` | `u8` | `2` | нет | Зарезервированный порог совместимости в текущей ревизии (активного runtime-consumer нет). | `degradation_min_unavailable_dc_groups = 2` |
+
+## Устаревшие / legacy параметры
+
+| Параметр | Статус | Замена | Текущее поведение | Рекомендация миграции |
+|---|---|---|---|---|
+| `general.middle_proxy_nat_stun` | Deprecated | `network.stun_servers` | Добавляется в `network.stun_servers`, только если `network.stun_servers` не задан явно. | Перенести значение в `network.stun_servers`, legacy-ключ удалить. |
+| `general.middle_proxy_nat_stun_servers` | Deprecated | `network.stun_servers` | Добавляется в `network.stun_servers`, только если `network.stun_servers` не задан явно. | Перенести значения в `network.stun_servers`, legacy-ключ удалить. |
+| `general.proxy_secret_auto_reload_secs` | Deprecated | `general.update_every` | Используется только если `update_every = null` (legacy fallback). | Явно задать `general.update_every`, legacy-ключ удалить. |
+| `general.proxy_config_auto_reload_secs` | Deprecated | `general.update_every` | Используется только если `update_every = null` (legacy fallback). | Явно задать `general.update_every`, legacy-ключ удалить. |
+
+## Как конфигурируются Upstreams
+
+### Схема upstream
+
+| Поле | Применимость | Тип | Обязательно | Default | Назначение |
+|---|---|---|---|---|---|
+| `[[upstreams]].type` | все upstream | `"direct" \| "socks4" \| "socks5"` | да | n/a | Тип upstream транспорта. |
+| `[[upstreams]].weight` | все upstream | `u16` | нет | `1` | Базовый вес в weighted-random выборе. |
+| `[[upstreams]].enabled` | все upstream | `bool` | нет | `true` | Выключенные записи игнорируются на старте. |
+| `[[upstreams]].scopes` | все upstream | `String` | нет | `""` | Список scope-токенов через запятую для маршрутизации. |
+| `interface` | `direct` | `Option<String>` | нет | `null` | Имя интерфейса (например `eth0`) или literal локальный IP. |
+| `bind_addresses` | `direct` | `Option<Vec<IpAddr>>` | нет | `null` | Явные кандидаты source IP (имеют приоритет над `interface`). |
+| `address` | `socks4` | `String` | да | n/a | Адрес SOCKS4 сервера (`ip:port` или `host:port`). |
+| `interface` | `socks4` | `Option<String>` | нет | `null` | Используется только если `address` задан как `ip:port`. |
+| `user_id` | `socks4` | `Option<String>` | нет | `null` | SOCKS4 user ID в CONNECT-запросе. |
+| `address` | `socks5` | `String` | да | n/a | Адрес SOCKS5 сервера (`ip:port` или `host:port`). |
+| `interface` | `socks5` | `Option<String>` | нет | `null` | Используется только если `address` задан как `ip:port`. |
+| `username` | `socks5` | `Option<String>` | нет | `null` | Логин SOCKS5 auth. |
+| `password` | `socks5` | `Option<String>` | нет | `null` | Пароль SOCKS5 auth. |
+
+### Runtime-правила
+
+1. Если `[[upstreams]]` отсутствует, loader добавляет один upstream `direct` по умолчанию.
+2. Scope-фильтрация — по точному совпадению токена:
+- если scope запроса задан -> используются только записи, где `scopes` содержит такой же токен;
+- если scope запроса не задан -> используются только записи с пустым `scopes`.
+3. Среди healthy upstream используется weighted-random выбор: `weight * latency_factor`.
+4. Если в отфильтрованном наборе нет healthy upstream, выбирается случайный из отфильтрованных.
+5. Порядок выбора bind для `direct`:
+- сначала `bind_addresses` (только IP нужного семейства);
+- если одновременно заданы `interface` (имя) и `bind_addresses`, каждый IP проверяется на принадлежность интерфейсу;
+- несовпадающие IP отбрасываются с `WARN`;
+- если валидных IP не осталось, используется unbound direct connect (`bind_ip=None`);
+- если `bind_addresses` не подходит, применяется `interface` (literal IP или адрес интерфейса).
+6. Для `socks4/socks5` с `address` в виде hostname интерфейсный bind не поддерживается и игнорируется с предупреждением.
+7. Runtime DNS overrides применяются к резолвингу hostname в upstream-подключениях.
+8. В ME-режиме выбранный upstream также используется для ME TCP dial path.
+9. В ME-режиме для `direct` upstream с bind/interface STUN-рефлексия выполняется bind-aware для KDF материала.
+10. В ME-режиме для SOCKS upstream используются `BND.ADDR/BND.PORT` для KDF, если адрес валиден/публичен и соответствует IP family.
+
+## Примеры конфигурации Upstreams
+
+### Пример 1: минимальный direct upstream
+
+```toml
+[[upstreams]]
+type = "direct"
+weight = 1
+enabled = true
+```
+
+### Пример 2: direct с interface + явными bind IP
+
+```toml
+[[upstreams]]
+type = "direct"
+interface = "eth0"
+bind_addresses = ["192.168.1.100", "192.168.1.101"]
+weight = 3
+enabled = true
+```
+
+### Пример 3: SOCKS5 upstream с аутентификацией
+
+```toml
+[[upstreams]]
+type = "socks5"
+address = "198.51.100.30:1080"
+username = "proxy-user"
+password = "proxy-pass"
+weight = 2
+enabled = true
+```
+
+### Пример 4: смешанные upstream с scopes
+
+```toml
+[[upstreams]]
+type = "direct"
+weight = 5
+enabled = true
+scopes = ""
+
+[[upstreams]]
+type = "socks5"
+address = "203.0.113.40:1080"
+username = "edge"
+password = "edgepass"
+weight = 3
+enabled = true
+scopes = "premium,me"
+```
+
+### Пример 5: профиль тюнинга под ME
+
+```toml
+[general]
+use_middle_proxy = true
+proxy_secret_path = "proxy-secret"
+middle_proxy_nat_probe = true
+stun_nat_probe_concurrency = 16
+middle_proxy_pool_size = 12
+me_keepalive_enabled = true
+me_keepalive_interval_secs = 20
+me_keepalive_jitter_secs = 4
+me_reconnect_max_concurrent_per_dc = 12
+me_reconnect_backoff_base_ms = 300
+me_reconnect_backoff_cap_ms = 10000
+me_reconnect_fast_retry_count = 10
+hardswap = true
+me_reinit_every_secs = 600
+me_hardswap_warmup_delay_min_ms = 500
+me_hardswap_warmup_delay_max_ms = 1200
+me_hardswap_warmup_extra_passes = 2
+me_hardswap_warmup_pass_backoff_base_ms = 400
+me_config_stable_snapshots = 3
+me_config_apply_cooldown_secs = 120
+proxy_secret_stable_snapshots = 3
+proxy_secret_rotate_runtime = true
+proxy_secret_len_max = 512
+update_every = 300
+me_pool_drain_ttl_secs = 120
+me_pool_min_fresh_ratio = 0.9
+me_reinit_drain_timeout_secs = 180
+
+[timeouts]
+me_one_retry = 8
+me_one_timeout_ms = 1200
+
+[network]
+stun_use = true
+stun_tcp_fallback = true
+stun_servers = [
+  "stun1.l.google.com:19302",
+  "stun2.l.google.com:19302"
+]
+http_ip_detect_urls = [
+  "https://api.ipify.org",
+  "https://ifconfig.me/ip"
+]
+```

docs/XRAY-SINGBOX-ROUTING.ru.md

@@ -0,0 +1,321 @@
+# SNI-маршрутизация в xray-core / sing-box + TLS-fronting
+
+## Термины (в контексте этого кейса)
+
+- **TLS-fronting домен** — домен, который фигурирует в TLS ClientHello как **SNI** (например, `petrovich.ru`): он используется как "маска" на L7 и как ключ маршрутизации в прокси-роутере.
+- **xray-core / sing-box** — локальный или удалённый L7/TLS-роутер (прокси), который:
+  1) принимает входящее TCP/TLS-соединение,
+  2) читает TLS ClientHello,
+  3) извлекает SNI,
+  4) по SNI выбирает outbound/апстрим,
+  5) устанавливает новое TCP-соединение к целевому хосту уже **от себя**.
+- **SNI (Server Name Indication)** — поле в TLS ClientHello, где клиент Telegram сообщает доменное имя для "маскировки"
+- **DNS-resolve на стороне L7-роутера** — если выходной адрес задан доменом (или роутер решил "всё равно идти по SNI"), то DNS резолвится **на стороне xray/sing-box**, а не на стороне Telegram-клиента
+
+---
+
+## Ключевая идея: куда на самом деле идёт соединение решает не то, что вы указали клиенту, а то как L7-роутер трактует SNI
+
+Механика:
+
+1) Telegram-клиенту вы можете указать **IP/домен telemt**,как "сервер".
+2) Между клиентом и telemt стоит xray-core/sing-box, который принимает TCP, читает TLS ClientHello и видит **SNI=petrovich.ru**
+3) Дальше роутер говорит: "Вижу SNI - направить на апстрим/маршрут N"
+4) И устанавливает исходящее соединение не "по тому IP, который пользователь подразумевал", а **по домену из SNI** (или по сопоставлению SNI→outbound), используя для определния его IP собственный DNS-кеш или резолвер
+5) `petrovich.ru` по A-записи указывает **не на IP telemt**, а значит при L7-маршрутизации трафик уйдёт на "оригинальный" сайт за этим доменом, а не в telemt: Telegram-клиент, естественно, не сможет получить ожидаемое поведение, потому что ответить с handshake на той стороне некому
+
+---
+
+## Схема №1 "Как это НЕ работает"
+
+```text
+Telegram Client
+   |
+   |  (указан IP/домен telemt)
+   v
+telemt instance
+````
+
+Ожидание: "я указал telemt -> значит трафик попадёт в telemt" - **нет!**
+
+---
+
+## Схема №2. "Как это реально работает с TLS/L7-роутером и SNI"
+
+```text
+Telegram Client
+   |
+   | 1) TCP/TLS connection: 
+   |    - ClientHello: 
+   |      - SNI=petrovich.ru
+   v
+xray-core / sing-box / любой L7 router
+   |
+   | 2) читает ClientHello -> вытаскивает SNI
+   | 3) выбирает маршрут по SNI
+   | 4) делает DNS для petrovich.ru 
+   | 5) подключается к полученному IP по TLS с этим SNI
+   v
+"Оригинальный" сайт, A-запись которого не на telemt
+   |
+   X  не telemt -> Telegram-клиент не коннектится как ожидалось
+```
+
+---
+
+## Почему указанный в клиенте IP/домен telemt "не спасает"
+
+Потому что в таком режиме xray/sing-box выступает как **точка терминации TCP/TLS**, можно сказать - TLS-инспектор на уровне ClientHello, это означает:
+
+* TCP-сессия от Telegram-клиента заканчивается на xray/sing-box
+* Дальше создаётся **новая** TCP-сессия "от имени" xray/sing-box к апстриму
+* Выбор апстрима делается правилами роутинга, а в TLS-сценариях самый удобный и распространённый ключ — **SNI**
+
+То есть, "куда идти дальше" определяется логикой L7-роутера:
+
+* либо правилами вида `if SNI == petrovich.ru -> outbound X`,
+* либо более "автоматическим" поведением: `подключаться к тому хосту, который указан в SNI`,
+* плюс кэш DNS и собственные резолверы роутера
+
+---
+
+## Что именно извлекается из TLS ClientHello и почему этого достаточно
+
+TLS ClientHello отправляется **в начале** TLS-сессии и, в классическом TLS без ECH, содержит SNI в открытом виде.
+
+Упрощённо:
+
+```text
+ClientHello:
+  - supported_versions
+  - cipher_suites
+  - extensions:
+      - server_name: petrovich.ru   <-- SNI
+      - alpn: h2/http1.1/...
+      - ...
+```
+
+Роутеру не нужно расшифровывать трафик и завершать TLS "как сервер" — часто достаточно просто прочитать первые пакеты и распарсить ClientHello, чтобы получить SNI и принять решение
+
+---
+
+## Типовой алгоритм SNI-роутинга
+
+1. Принять входящий TCP.
+2. Подождать первые байты.
+3. Определить протокол:
+
+   * если видим TLS ClientHello → парсим SNI/ALPN
+4. Применить route rules:
+
+   * match по `server_name` / `domain` / `tls.sni`
+5. Выбрать outbound:
+
+   * direct / proxy / specific upstream / detour
+6. Установить исходящее соединение:
+
+   * либо на фиксированный IP:порт,
+   * либо на домен через DNS-resolve на стороне роутера
+7. Начать проксирование данных между входом и выходом
+
+---
+
+## Почему "A-запись фронтинг-домена не на telemt" ломает кейс
+
+### Ситуация
+
+* В ClientHello: `SNI = petrovich.ru`
+* DNS: `petrovich.ru -> 203.0.113.77`  - "оригинальный" сайт
+* telemt живёт на: `198.51.100.10`
+
+### Что делает роутер
+
+* Видит SNI `petrovich.ru`
+* Либо:
+
+  * (а) напрямую коннектится к `petrovich.ru:443`, резолвя A-запись в `203.0.113.77`,
+  * либо:
+  * (б) выбирает outbound, который указывает на `petrovich.ru` как destination,
+  * либо:
+  * (в) делает sniffing/override destination по SNI
+
+В итоге исходящий коннект идёт на `203.0.113.77:443`, а не на telemt!
+Другой сервер, другой протокол, другая логика, где telemt не участвует
+
+---
+
+## "Где именно происходит подмена destination на SNI"
+
+Это зависит от конфигурации, но типовые варианты:
+
+### Вариант A: outbound задан доменом (и он совпадает с SNI)
+
+Правило по SNI выбирает outbound, у которого destination задан доменом фронтинга, 
+тогда DNS резолвится на стороне роутера и вы уходите на "оригинальный" хост
+
+### Вариант B: destination override / sniffing
+
+Роутер "снифает" SNI и **перезаписывает** destination на домен из SNI (даже если вход изначально был на IP telemt),
+это особенно коварно: пользователь видит "я подключаюсь к IP telemt", но роутер после sniffing решает иначе
+
+### Вариант C: split DNS / кеш / независимый резолвер
+
+Даже если клиент "где-то" резолвит иначе, это не важно: конечный DNS для исходящего коннекта — на стороне xray/sing-box,
+который может иметь:
+
+* свой DoH/DoT,
+* свой кеш,
+* свои правила fake-ip / system resolver,
+* и, как следствие, своя "карта" **домен/SNI -> IP**
+
+---
+
+## Признаки того, что трафик "утёк на оригинал", а не попал в telemt
+
+* На стороне telemt отсутствуют входящие соединения/логи
+* На стороне роутера видно, что destination — домен фронтинга, а IP соответствует публичному сайту
+* TLS-метрики/сертификат на выходе соответствует "оригинальному" сайту в записах трафика
+* Telegram-клиент получает неожиданный тип ответов/ошибку handshaking/timeout в debug-режиме
+
+---
+
+## Best-practice решение для этого кейса: свой домен фронтинга + заглушка на telemt + Let's Encrypt
+
+### Цель
+
+Сделать так, чтобы:
+
+* SNI (фронтинг-домен) **резолвился в IP telemt**,
+* на IP telemt реально был TLS-сервис с валидным сертификатом под этот домен,
+* даже если кто-то "попробует открыть домен как сайт", он увидит нормальную заглушку, а не "пустоту"
+
+### Что это даёт
+
+* xray/sing-box, маршрутизируя по SNI, будет неизбежно приходить на telemt, потому что DNS(SNI-домен) → IP telemt
+* Внешний вид будет правдоподобным: обычный домен с обычным сертификатом
+* Устойчивость: меньше сюрпризов от DNS-кеша/перерезолва/"умных" правил роутера
+
+---
+
+## Рекомендуемая схема (целевое состояние)
+
+```text
+Telegram Client
+   |
+   | TLS ClientHello: SNI = hello.example.com
+   v
+xray-core / sing-box
+   |
+   | Route by SNI -> outbound -> connect to hello.example.com:443
+   | DNS(hello.example.com) = IP telemt
+   v
+telemt instance (IP telemt)
+   |
+   | TLS cert for hello.example.com (Let's Encrypt)
+   | + сайт-заглушка / health endpoint
+   v
+OK
+```
+
+---
+
+## Практический чеклист (минимальный)
+
+1. Купить/иметь домен: `hello.example.com`
+2. В DNS:
+
+   * `A hello.example.com -> <IP telemt>`
+   * (опционально) AAAA, если используете IPv6 и он стабилен
+3. На telemt-хосте:
+
+   * поднять TLS endpoint на 443 с валидным сертификатом LE под `hello.example.com`
+   * отдать "заглушку" (например, статический сайт), чтобы домен выглядел как обычный веб-сервис
+4. В xray/sing-box правилах:
+
+   * маршрутизировать нужный трафик по SNI = `hello.example.com` в "правильный" outbound (к telemt)
+   * избегать конфигураций, где destination override уводит на чужой домен
+5. Важно:
+
+   * если вы используете кеш DNS на роутере — сбросить/обновить его после смены A-записи
+
+---
+
+## Пояснение про сайт-заглушку
+
+Для эмуляции TLS, telemt имеет подсистему TLS-F в `src/tls_front`:
+- её модуль - fetcher, собирает TLS-профили, чтоб максимально поведенчески корректно повторять TLS конкретно указанного сайта
+
+Когда вы указываете сайт, который не отвечает по TLS:
+- fetcher не может собрать TLS-профиль и происходит fallback на `fake_cert_len` - примитивный алгоритм,
+- он забивает служебную информацию TLS рандомными байтами,
+- простые системы DPI не распознают это
+- однако, продвинутые системы, такие как nEdge или Fraud Control в сетях мобильной связи легко заблокируют или замедлят такой трафик
+
+Создав сайт-заглушку с Let's Encrypt сертификатом, вы даёте TLS-F возможность получить данные сертификата и корректно его "повторять" в дальнейшем
+
+---
+
+## Вариант конфиг-подхода: "SNI строго привязываем к telemt - фиксированный IP"
+
+Чтобы полностью исключить зависимость от DNS если вам это нужно, можно сделать outbound, который ходит на **фиксированный IP telemt**, но при этом выставляет SNI/Host как `hello.example.com`.
+
+Идея:
+
+* destination: `IP:443`
+* SNI: `hello.example.com`
+* сертификат на telemt именно под `hello.example.com`
+
+Так вы получаете:
+
+* TLS выглядит корректно, ведь SNI совпадает с сертификатом,
+* а routing никогда не уйдёт на "оригинал", потому что A-запись указывает на telemt и контроллируется вами!
+
+Но в вашем описании проблема как раз в том, что роутер "сам решает по SNI и резолвит домен", поэтому самый универсальный вариант — сделать так, чтобы DNS всегда приводил в telemt
+
+---
+
+## Пример логики правил на псевдоконфиге L7-роутера
+
+```text
+if inbound is TLS and sni == "hello.example.com":
+    route -> outbound "telemt"
+else:
+    route -> outbound "default"
+```
+
+Outbound `telemt`:
+
+* destination: `hello.example.com:443`
+* TLS enabled
+* SNI: `hello.example.com`
+
+---
+
+## Отдельно: что может неожиданно сломать даже "правильный" DNS
+
+* **Кеширование DNS** на xray/sing-box или на системном резолвере, особенно при смене A-записи
+* **Split-horizon DNS**: разные ответы внутри/снаружи, попытки подмены/терминирования в других точках
+* **IPv6**: если есть AAAA и он указывает не туда, роутер может предпочесть IPv6: помните, что поддержка v6 нестабильна и не рекомендуется в prod
+* **DoH/DoT** на роутере: он может резолвить не тем резолвером, которым вы проверяли
+
+Минимальная гигиена:
+
+* контролировать A/AAAA,
+* держать TTL разумным,
+* проверять, каким резолвером пользуется именно роутер,
+* при необходимости отключить/ограничить destination override
+
+---
+
+## Итог
+
+В режиме TLS-fronting с xray-core/sing-box как L7/TLS-роутером **SNI становится приоритетным "source-of-truth" для маршрутизации**
+
+Если фронтинг-домен по DNS указывает не на IP telemt, роутер честно уводит трафик на "оригинальный" сайт, потому что он строит исходящее соединение "по SNI"
+
+Надёжное решение для этого кейса:
+
+* использовать **свой домен** для фронтинга,
+* направить его **A/AAAA** на IP telemt,
+* поднять на telemt **TLS-сервис с Let’s Encrypt сертификатом** под этот домен,
+* (желательно) держать **сайт-заглушку**, чтобы 443 выглядел как обычный HTTPS

docs/model/MODEL.en.md

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+# Telemt Runtime Model
+
+## Scope
+This document defines runtime concepts used by the Middle-End (ME) transport pipeline and the orchestration logic around it.
+
+It focuses on:
+- `ME Pool / Reader / Writer / Refill / Registry`
+- `Adaptive Floor`
+- `Trio-State`
+- `Generation Lifecycle`
+
+## Core Entities
+
+### ME Pool
+`ME Pool` is the runtime orchestrator for all Middle-End writers.
+
+Responsibilities:
+- Holds writer inventory by DC/family/endpoint.
+- Maintains routing primitives and writer selection policy.
+- Tracks generation state (`active`, `warm`, `draining` context).
+- Applies runtime policies (floor mode, refill, reconnect, reinit, fallback behavior).
+- Exposes readiness gates used by admission logic (for conditional accept/cast behavior).
+
+Non-goals:
+- It does not own client protocol decoding.
+- It does not own per-client business policy (quotas/limits).
+
+### ME Writer
+`ME Writer` is a long-lived ME RPC tunnel bound to one concrete ME endpoint (`ip:port`), with:
+- Outbound command channel (send path).
+- Associated reader loop (inbound path).
+- Health/degraded flags.
+- Contour/state and generation metadata.
+
+A writer is the actual data plane carrier for client sessions once bound.
+
+### ME Reader
+`ME Reader` is the inbound parser/dispatcher for one writer:
+- Reads/decrypts ME RPC frames.
+- Validates sequence/checksum.
+- Routes payloads to client-connection channels via `Registry`.
+- Emits close/ack/data events and updates telemetry.
+
+Design intent:
+- Reader must stay non-blocking as much as possible.
+- Backpressure on a single client route must not stall the whole writer stream.
+
+### Refill
+`Refill` is the recovery mechanism that restores writer coverage when capacity drops:
+- Per-endpoint restore (same endpoint first).
+- Per-DC restore to satisfy required floor.
+- Optional outage-mode/shadow behavior for fragile single-endpoint DCs.
+
+Refill works asynchronously and should not block hot routing paths.
+
+### Registry
+`Registry` is the routing index between ME and client sessions:
+- `conn_id -> client response channel`
+- `conn_id <-> writer_id` binding map
+- writer activity snapshots and idle tracking
+
+Main invariants:
+- A `conn_id` routes to at most one active response channel.
+- Writer loss triggers safe unbind/cleanup and close propagation.
+- Registry state is the source of truth for active ME-bound session mapping.
+
+## Adaptive Floor
+
+### What it is
+`Adaptive Floor` is a runtime policy that changes target writer count per DC based on observed activity, instead of always holding static peak floor.
+
+### Why it exists
+Goals:
+- Reduce idle writer churn under low traffic.
+- Keep enough warm capacity to avoid client-visible stalls on burst recovery.
+- Limit needless reconnect storms on unstable endpoints.
+
+### Behavioral model
+- Under activity: floor converges toward configured static requirement.
+- Under prolonged idle: floor can shrink to a safe minimum.
+- Recovery/grace windows prevent aggressive oscillation.
+
+### Safety constraints
+- Never violate minimal survivability floor for a DC group.
+- Refill must still restore quickly on demand.
+- Floor adaptation must not force-drop already bound healthy sessions.
+
+## Trio-State
+
+`Trio-State` is writer contouring:
+- `Warm`
+- `Active`
+- `Draining`
+
+### State semantics
+- `Warm`: connected and validated, not primary for new binds.
+- `Active`: preferred for new binds and normal traffic.
+- `Draining`: no new regular binds; existing sessions continue until graceful retirement rules apply.
+
+### Transition intent
+- `Warm -> Active`: when coverage/readiness conditions are satisfied.
+- `Active -> Draining`: on generation swap, endpoint replacement, or controlled retirement.
+- `Draining -> removed`: after drain TTL/force-close policy (or when naturally empty).
+
+This separation reduces SPOF and keeps cutovers predictable.
+
+## Generation Lifecycle
+
+Generation isolates pool epochs during reinit/reconfiguration.
+
+### Lifecycle phases
+1. `Bootstrap`: initial writers are established.
+2. `Warmup`: next generation writers are created and validated.
+3. `Activation`: generation promoted to active when coverage gate passes.
+4. `Drain`: previous generation becomes draining, existing sessions are allowed to finish.
+5. `Retire`: old generation writers are removed after graceful rules.
+
+### Operational guarantees
+- No partial generation activation without minimum coverage.
+- Existing healthy client sessions should not be dropped just because a new generation appears.
+- Draining generation exists to absorb in-flight traffic during swap.
+
+### Readiness and admission
+Pool readiness is not equivalent to “all endpoints fully saturated”.
+Typical gating strategy:
+- Open admission when per-DC minimal alive coverage exists.
+- Continue background saturation for multi-endpoint DCs.
+
+This keeps startup latency low while preserving eventual full capacity.
+
+## Interactions Between Concepts
+
+- `Generation` defines pool epochs.
+- `Trio-State` defines per-writer role inside/around those epochs.
+- `Adaptive Floor` defines how much capacity should be maintained right now.
+- `Refill` is the actuator that closes the gap between desired and current capacity.
+- `Registry` keeps per-session routing correctness while all of the above changes over time.
+
+## Architectural Approach
+
+### Layered Design
+The runtime is intentionally split into two planes:
+- `Control Plane`: decides desired topology and policy (`floor`, `generation swap`, `refill`, `fallback`).
+- `Data Plane`: executes packet/session transport (`reader`, `writer`, routing, acks, close propagation).
+
+Architectural rule:
+- Control Plane may change writer inventory and policy.
+- Data Plane must remain stable and low-latency while those changes happen.
+
+### Ownership Model
+Ownership is centered around explicit state domains:
+- `MePool` owns writer lifecycle and policy state.
+- `Registry` owns per-connection routing bindings.
+- `Writer task` owns outbound ME socket send progression.
+- `Reader task` owns inbound ME socket parsing and event dispatch.
+
+This prevents accidental cross-layer mutation and keeps invariants local.
+
+### Control Plane Responsibilities
+Control Plane is event-driven and policy-driven:
+- Startup initialization and readiness gates.
+- Runtime reinit (periodic or config-triggered).
+- Coverage checks per DC/family/endpoint group.
+- Floor enforcement (static/adaptive).
+- Refill scheduling and retry orchestration.
+- Generation transition (`warm -> active`, previous `active -> draining`).
+
+Control Plane must prioritize determinism over short-term aggressiveness.
+
+### Data Plane Responsibilities
+Data Plane is throughput-first and allocation-sensitive:
+- Session bind to writer.
+- Per-frame parsing/validation and dispatch.
+- Ack and close signal propagation.
+- Route drop behavior under missing connection or closed channel.
+- Minimal critical logging in hot path.
+
+Data Plane should avoid waiting on operations that are not strictly required for frame correctness.
+
+## Concurrency and Synchronization
+
+### Concurrency Principles
+- Per-writer isolation: each writer has independent send/read task loops.
+- Per-connection isolation: client channel state is scoped by `conn_id`.
+- Asynchronous recovery: refill/reconnect runs outside the packet hot path.
+
+### Synchronization Strategy
+- Shared maps use fine-grained, short-lived locking.
+- Read-mostly paths avoid broad write-lock windows.
+- Backpressure decisions are localized at route/channel boundary.
+
+Design target:
+- A slow consumer should degrade only itself (or its route), not global writer progress.
+
+### Cancellation and Shutdown
+Writer and reader loops are cancellation-aware:
+- explicit cancel token / close command support;
+- safe unbind and cleanup via registry;
+- deterministic order: stop admission -> drain/close -> release resources.
+
+## Consistency Model
+
+### Session Consistency
+For one `conn_id`:
+- exactly one active route target at a time;
+- close and unbind must be idempotent;
+- writer loss must not leave dangling bindings.
+
+### Generation Consistency
+Generational consistency guarantees:
+- New generation is not promoted before minimum coverage gate.
+- Previous generation remains available in `draining` state during handover.
+- Forced retirement is policy-bound (`drain ttl`, optional force-close), not immediate.
+
+### Policy Consistency
+Policy changes (`adaptive/static floor`, fallback mode, retries) should apply without violating established active-session routing invariants.
+
+## Backpressure and Flow Control
+
+### Route-Level Backpressure
+Route channels are bounded by design.
+When pressure increases:
+- short burst absorption is allowed;
+- prolonged congestion triggers controlled drop semantics;
+- drop accounting is explicit via metrics/counters.
+
+### Reader Non-Blocking Priority
+Inbound ME reader path should never be serialized behind one congested client route.
+Practical implication:
+- prefer non-blocking route attempt in the parser loop;
+- move heavy recovery to async side paths.
+
+## Failure Domain Strategy
+
+### Endpoint-Level Failure
+Failure of one endpoint should trigger endpoint-scoped recovery first:
+- same endpoint reconnect;
+- endpoint replacement within same DC group if applicable.
+
+### DC-Level Degradation
+If a DC group cannot satisfy floor:
+- keep service via remaining coverage if policy allows;
+- continue asynchronous refill saturation in background.
+
+### Whole-Pool Readiness Loss
+If no sufficient ME coverage exists:
+- admission gate can hold new accepts (conditional policy);
+- existing sessions should continue when their path remains healthy.
+
+## Performance Architecture Notes
+
+### Hotpath Discipline
+Allowed in hotpath:
+- fixed-size parsing and cheap validation;
+- bounded channel operations;
+- precomputed or low-allocation access patterns.
+
+Avoid in hotpath:
+- repeated expensive decoding;
+- broad locks with awaits inside critical sections;
+- verbose high-frequency logging.
+
+### Throughput Stability Over Peak Spikes
+Architecture prefers stable throughput and predictable latency over short peak gains that increase churn or long-tail reconnect times.
+
+## Evolution and Extension Rules
+
+To evolve this model safely:
+- Add new policy knobs in Control Plane first.
+- Keep Data Plane contracts stable (`conn_id`, route semantics, close semantics).
+- Validate generation and registry invariants before enabling by default.
+- Introduce new retry/recovery strategies behind explicit config.
+
+## Failure and Recovery Notes
+
+- Single-endpoint DC failure is a normal degraded mode case; policy should prioritize fast reconnect and optional shadow/probing strategies.
+- Idle close by peer should be treated as expected when upstream enforces idle timeout.
+- Reconnect backoff must protect against synchronized churn while still allowing fast first retries.
+- Fallback (`ME -> direct DC`) is a policy switch, not a transport bug by itself.
+
+## Terminology Summary
+- `Coverage`: enough live writers to satisfy per-DC acceptance policy.
+- `Floor`: target minimum writer count policy.
+- `Churn`: frequent writer reconnect/remove cycles.
+- `Hotpath`: per-packet/per-connection data path where extra waits/allocations are expensive.

docs/model/MODEL.ru.md

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+# Runtime-модель Telemt
+
+## Область описания
+Документ фиксирует ключевые runtime-понятия пайплайна Middle-End (ME) и оркестрации вокруг него.
+
+Фокус:
+- `ME Pool / Reader / Writer / Refill / Registry`
+- `Adaptive Floor`
+- `Trio-State`
+- `Generation Lifecycle`
+
+## Базовые сущности
+
+### ME Pool
+`ME Pool` — центральный оркестратор всех Middle-End writer-ов.
+
+Зона ответственности:
+- хранит инвентарь writer-ов по DC/family/endpoint;
+- управляет выбором writer-а и маршрутизацией;
+- ведёт состояние поколений (`active`, `warm`, `draining` контекст);
+- применяет runtime-политики (floor, refill, reconnect, reinit, fallback);
+- отдаёт сигналы готовности для admission-логики (conditional accept/cast).
+
+Что не делает:
+- не декодирует клиентский протокол;
+- не реализует бизнес-политику пользователя (квоты/лимиты).
+
+### ME Writer
+`ME Writer` — долгоживущий ME RPC-канал к конкретному endpoint (`ip:port`), у которого есть:
+- канал команд на отправку;
+- связанный reader loop для входящего потока;
+- флаги состояния/деградации;
+- метаданные contour/state и generation.
+
+Writer — это фактический data-plane носитель клиентских сессий после бинда.
+
+### ME Reader
+`ME Reader` — входной parser/dispatcher одного writer-а:
+- читает и расшифровывает ME RPC-фреймы;
+- проверяет sequence/checksum;
+- маршрутизирует payload в client-каналы через `Registry`;
+- обрабатывает close/ack/data и обновляет телеметрию.
+
+Инженерный принцип:
+- Reader должен оставаться неблокирующим.
+- Backpressure одной клиентской сессии не должен останавливать весь поток writer-а.
+
+### Refill
+`Refill` — механизм восстановления покрытия writer-ов при просадке:
+- восстановление на том же endpoint в первую очередь;
+- восстановление по DC до требуемого floor;
+- опциональные outage/shadow-режимы для хрупких single-endpoint DC.
+
+Refill работает асинхронно и не должен блокировать hotpath.
+
+### Registry
+`Registry` — маршрутизационный индекс между ME и клиентскими сессиями:
+- `conn_id -> канал ответа клиенту`;
+- map биндов `conn_id <-> writer_id`;
+- снимки активности writer-ов и idle-трекинг.
+
+Ключевые инварианты:
+- один `conn_id` маршрутизируется максимум в один активный канал ответа;
+- потеря writer-а приводит к безопасному unbind/cleanup и отправке close;
+- именно `Registry` является источником истины по активным ME-биндам.
+
+## Adaptive Floor
+
+### Что это
+`Adaptive Floor` — runtime-политика, которая динамически меняет целевое число writer-ов на DC в зависимости от активности, а не держит всегда фиксированный статический floor.
+
+### Зачем
+Цели:
+- уменьшить churn на idle-трафике;
+- сохранить достаточную прогретую ёмкость для быстрых всплесков;
+- снизить лишние reconnect-штормы на нестабильных endpoint.
+
+### Модель поведения
+- при активности floor стремится к статическому требованию;
+- при длительном idle floor может снижаться до безопасного минимума;
+- grace/recovery окна не дают системе "флапать" слишком резко.
+
+### Ограничения безопасности
+- нельзя нарушать минимальный floor выживаемости DC-группы;
+- refill обязан быстро нарастить покрытие по запросу;
+- адаптация не должна принудительно ронять уже привязанные healthy-сессии.
+
+## Trio-State
+
+`Trio-State` — контурная роль writer-а:
+- `Warm`
+- `Active`
+- `Draining`
+
+### Семантика состояний
+- `Warm`: writer подключён и валиден, но не основной для новых биндов.
+- `Active`: приоритетный для новых биндов и обычного трафика.
+- `Draining`: новые обычные бинды не назначаются; текущие сессии живут до правил graceful-вывода.
+
+### Логика переходов
+- `Warm -> Active`: когда достигнуты условия покрытия/готовности.
+- `Active -> Draining`: при swap поколения, замене endpoint или контролируемом выводе.
+- `Draining -> removed`: после drain TTL/force-close политики (или естественного опустошения).
+
+Такое разделение снижает SPOF-риски и делает cutover предсказуемым.
+
+## Generation Lifecycle
+
+Generation изолирует эпохи пула при reinit/reconfiguration.
+
+### Фазы жизненного цикла
+1. `Bootstrap`: поднимается начальный набор writer-ов.
+2. `Warmup`: создаётся и валидируется новое поколение.
+3. `Activation`: новое поколение становится active после прохождения coverage-gate.
+4. `Drain`: предыдущее поколение переводится в draining, текущим сессиям дают завершиться.
+5. `Retire`: старое поколение удаляется по graceful-правилам.
+
+### Операционные гарантии
+- нельзя активировать поколение частично без минимального покрытия;
+- healthy-клиенты не должны теряться только из-за появления нового поколения;
+- draining-поколение служит буфером для in-flight трафика во время swap.
+
+### Готовность и приём клиентов
+Готовность пула не равна "все endpoint полностью насыщены".
+Типичная стратегия:
+- открыть admission при минимально достаточном alive-покрытии по DC;
+- параллельно продолжать saturation для multi-endpoint DC.
+
+Это уменьшает startup latency и сохраняет выход на полную ёмкость.
+
+## Как понятия связаны между собой
+
+- `Generation` задаёт эпохи пула.
+- `Trio-State` задаёт роль каждого writer-а внутри/между эпохами.
+- `Adaptive Floor` задаёт, сколько ёмкости нужно сейчас.
+- `Refill` — исполнитель, который закрывает разницу между desired и current capacity.
+- `Registry` гарантирует корректную маршрутизацию сессий, пока всё выше меняется.
+
+## Архитектурный подход
+
+### Слоистая модель
+Runtime специально разделён на две плоскости:
+- `Control Plane`: принимает решения о целевой топологии и политиках (`floor`, `generation swap`, `refill`, `fallback`).
+- `Data Plane`: исполняет транспорт сессий и пакетов (`reader`, `writer`, маршрутизация, ack, close).
+
+Ключевое правило:
+- Control Plane может менять состав writer-ов и policy.
+- Data Plane должен оставаться стабильным и низколатентным в момент этих изменений.
+
+### Модель владения состоянием
+Владение разделено по доменам:
+- `MePool` владеет жизненным циклом writer-ов и policy-state.
+- `Registry` владеет routing-биндами клиентских сессий.
+- `Writer task` владеет исходящей прогрессией ME-сокета.
+- `Reader task` владеет входящим парсингом и dispatch-событиями.
+
+Это ограничивает побочные мутации и локализует инварианты.
+
+### Обязанности Control Plane
+Control Plane работает событийно и policy-ориентированно:
+- стартовая инициализация и readiness-gate;
+- runtime reinit (периодический и/или по изменению конфигурации);
+- проверки покрытия по DC/family/endpoint group;
+- применение floor-политики (static/adaptive);
+- планирование refill и orchestration retry;
+- переходы поколений (`warm -> active`, прежний `active -> draining`).
+
+Для него важнее детерминизм, чем агрессивная краткосрочная реакция.
+
+### Обязанности Data Plane
+Data Plane ориентирован на пропускную способность и предсказуемую задержку:
+- bind клиентской сессии к writer-у;
+- per-frame parsing/validation/dispatch;
+- распространение ack/close;
+- корректная реакция на missing conn/closed channel;
+- минимальный лог-шум в hotpath.
+
+Data Plane не должен ждать операций, не критичных для корректности текущего фрейма.
+
+## Конкурентность и синхронизация
+
+### Принципы конкурентности
+- Изоляция по writer-у: у каждого writer-а независимые send/read loop.
+- Изоляция по сессии: состояние канала локально для `conn_id`.
+- Асинхронное восстановление: refill/reconnect выполняются вне пакетного hotpath.
+
+### Стратегия синхронизации
+- Для shared map используются короткие и узкие lock-секции.
+- Read-heavy пути избегают длительных write-lock окон.
+- Решения по backpressure локализованы на границе route/channel.
+
+Цель:
+- медленный consumer должен деградировать локально, не останавливая глобальный прогресс writer-а.
+
+### Cancellation и shutdown
+Reader/Writer loop должны быть cancellation-aware:
+- явные cancel token / close command;
+- безопасный unbind/cleanup через registry;
+- детерминированный порядок: stop admission -> drain/close -> release resources.
+
+## Модель согласованности
+
+### Согласованность сессии
+Для одного `conn_id`:
+- одновременно ровно один активный route-target;
+- close/unbind операции идемпотентны;
+- потеря writer-а не оставляет dangling-бинды.
+
+### Согласованность поколения
+Гарантии generation:
+- новое поколение не активируется до прохождения минимального coverage-gate;
+- предыдущее поколение остаётся в `draining` на время handover;
+- принудительный вывод writer-ов ограничен policy (`drain ttl`, optional force-close), а не мгновенный.
+
+### Согласованность политик
+Изменение policy (`adaptive/static floor`, fallback mode, retries) не должно ломать инварианты маршрутизации уже активных сессий.
+
+## Backpressure и управление потоком
+
+### Route-level backpressure
+Route-каналы намеренно bounded.
+При росте нагрузки:
+- кратковременный burst поглощается;
+- длительная перегрузка переходит в контролируемую drop-семантику;
+- все drop-сценарии должны быть прозрачно видны в метриках.
+
+### Приоритет неблокирующего Reader
+Входящий ME-reader path не должен сериализоваться из-за одной перегруженной клиентской сессии.
+Практически это означает:
+- использовать неблокирующую попытку route в parser loop;
+- выносить тяжёлое восстановление в асинхронные side-path.
+
+## Стратегия доменов отказа
+
+### Отказ отдельного endpoint
+Сначала применяется endpoint-local recovery:
+- reconnect в тот же endpoint;
+- затем замена endpoint внутри той же DC-группы (если доступно).
+
+### Деградация уровня DC
+Если DC-группа не набирает floor:
+- сервис сохраняется на остаточном покрытии (если policy разрешает);
+- saturation refill продолжается асинхронно в фоне.
+
+### Потеря готовности всего пула
+Если достаточного ME-покрытия нет:
+- admission gate может временно закрыть приём новых подключений (conditional policy);
+- уже активные сессии продолжают работать, пока их маршрут остаётся healthy.
+
+## Архитектурные заметки по производительности
+
+### Дисциплина hotpath
+Допустимо в hotpath:
+- фиксированный и дешёвый parsing/validation;
+- bounded channel operations;
+- precomputed/low-allocation доступ к данным.
+
+Нежелательно в hotpath:
+- повторные дорогие decode;
+- широкие lock-секции с `await` внутри;
+- высокочастотный подробный logging.
+
+### Стабильность важнее пиков
+Архитектура приоритетно выбирает стабильную пропускную способность и предсказуемую latency, а не краткосрочные пики ценой churn и long-tail reconnect.
+
+## Правила эволюции модели
+
+Чтобы расширять модель безопасно:
+- новые policy knobs сначала внедрять в Control Plane;
+- контракты Data Plane (`conn_id`, route/close семантика) держать стабильными;
+- перед дефолтным включением проверять generation/registry инварианты;
+- новые recovery/retry стратегии вводить через явный config-флаг.
+
+## Нюансы отказов и восстановления
+
+- падение single-endpoint DC — штатный деградированный сценарий; приоритет: быстрый reconnect и, при необходимости, shadow/probing;
+- idle-close со стороны peer должен считаться нормальным событием при upstream idle-timeout;
+- backoff reconnect-логики должен ограничивать синхронный churn, но сохранять быстрые первые попытки;
+- fallback (`ME -> direct DC`) — это переключаемая policy-ветка, а не автоматический признак бага транспорта.
+
+## Краткий словарь
+- `Coverage`: достаточное число живых writer-ов для политики приёма по DC.
+- `Floor`: целевая минимальная ёмкость writer-ов.
+- `Churn`: частые циклы reconnect/remove writer-ов.
+- `Hotpath`: пер-пакетный/пер-коннектный путь, где любые лишние ожидания и аллокации особенно дороги.

install.sh

@@ -0,0 +1,73 @@
+sudo bash -c '
+set -e
+
+# --- Проверка на существующую установку ---
+if systemctl list-unit-files | grep -q telemt.service; then
+    # --- РЕЖИМ ОБНОВЛЕНИЯ ---
+    echo "--- Обнаружена существующая установка Telemt. Запускаю обновление... ---"
+
+    echo "[*] Остановка службы telemt..."
+    systemctl stop telemt || true # Игнорируем ошибку, если служба уже остановлена
+
+    echo "[1/2] Скачивание последней версии Telemt..."
+    wget -qO- "https://github.com/telemt/telemt/releases/latest/download/telemt-$(uname -m)-linux-$(ldd --version 2>&1 | grep -iq musl && echo musl || echo gnu).tar.gz" | tar -xz
+
+    echo "[1/2] Замена исполняемого файла в /usr/local/bin..."
+    mv telemt /usr/local/bin/telemt
+    chmod +x /usr/local/bin/telemt
+
+    echo "[2/2] Запуск службы..."
+    systemctl start telemt
+
+    echo "--- Обновление Telemt успешно завершено! ---"
+    echo
+    echo "Для проверки статуса службы выполните:"
+    echo "   systemctl status telemt"
+
+else
+    # --- РЕЖИМ НОВОЙ УСТАНОВКИ ---
+    echo "--- Начало автоматической установки Telemt ---"
+
+    # Шаг 1: Скачивание и установка бинарного файла
+    echo "[1/5] Скачивание последней версии Telemt..."
+    wget -qO- "https://github.com/telemt/telemt/releases/latest/download/telemt-$(uname -m)-linux-$(ldd --version 2>&1 | grep -iq musl && echo musl || echo gnu).tar.gz" | tar -xz
+
+    echo "[1/5] Перемещение исполняемого файла в /usr/local/bin и установка прав..."
+    mv telemt /usr/local/bin/telemt
+    chmod +x /usr/local/bin/telemt
+
+    # Шаг 2: Генерация секрета
+    echo "[2/5] Генерация секретного ключа..."
+    SECRET=$(openssl rand -hex 16)
+
+    # Шаг 3: Создание файла конфигурации
+    echo "[3/5] Создание файла конфигурации /etc/telemt.toml..."
+    printf "# === General Settings ===\n[general]\n[general.modes]\nclassic = false\nsecure = false\ntls = true\n\n# === Anti-Censorship & Masking ===\n[censorship]\n# !!! ВАЖНО: Замените на ваш домен или домен, который вы хотите использовать для маскировки !!!\ntls_domain = \"petrovich.ru\"\n\n[access.users]\nhello = \"%s\"\n" "$SECRET" > /etc/telemt.toml
+
+    # Шаг 4: Создание службы Systemd
+    echo "[4/5] Создание службы systemd..."
+    printf "[Unit]\nDescription=Telemt Proxy\nAfter=network.target\n\n[Service]\nType=simple\nExecStart=/usr/local/bin/telemt /etc/telemt.toml\nRestart=on-failure\nRestartSec=5\nLimitNOFILE=65536\n\n[Install]\nWantedBy=multi-user.target\n" > /etc/systemd/system/telemt.service
+
+    # Шаг 5: Запуск службы
+    echo "[5/5] Перезагрузка systemd, запуск и включение службы telemt..."
+    systemctl daemon-reload
+    systemctl start telemt
+    systemctl enable telemt
+
+    echo "--- Установка и запуск Telemt успешно завершены! ---"
+    echo
+    echo "ВАЖНАЯ ИНФОРМАЦИЯ:"
+    echo "==================="
+    echo "1. Вам НЕОБХОДИМО отредактировать файл /etc/telemt.toml и заменить '\''petrovich.ru'\'' на другой домен"
+    echo "   с помощью команды:"
+    echo "   nano /etc/telemt.toml"
+    echo "   После редактирования файла перезапустите службу командой:"
+    echo "   sudo systemctl restart telemt"
+    echo
+    echo "2. Для проверки статуса службы выполните команду:"
+    echo "   systemctl status telemt"
+    echo
+    echo "3. Для получения ссылок на подключение выполните команду:"
+    echo "   journalctl -u telemt -n -g '\''links'\'' --no-pager -o cat | tac"
+fi
+'

src/api/config_store.rs

@@ -0,0 +1,107 @@
+use std::io::Write;
+use std::path::{Path, PathBuf};
+
+use hyper::header::IF_MATCH;
+use sha2::{Digest, Sha256};
+
+use crate::config::ProxyConfig;
+
+use super::model::ApiFailure;
+
+pub(super) fn parse_if_match(headers: &hyper::HeaderMap) -> Option<String> {
+    headers
+        .get(IF_MATCH)
+        .and_then(|value| value.to_str().ok())
+        .map(str::trim)
+        .filter(|value| !value.is_empty())
+        .map(|value| value.trim_matches('"').to_string())
+}
+
+pub(super) async fn ensure_expected_revision(
+    config_path: &Path,
+    expected_revision: Option<&str>,
+) -> Result<(), ApiFailure> {
+    let Some(expected) = expected_revision else {
+        return Ok(());
+    };
+    let current = current_revision(config_path).await?;
+    if current != expected {
+        return Err(ApiFailure::new(
+            hyper::StatusCode::CONFLICT,
+            "revision_conflict",
+            "Config revision mismatch",
+        ));
+    }
+    Ok(())
+}
+
+pub(super) async fn current_revision(config_path: &Path) -> Result<String, ApiFailure> {
+    let content = tokio::fs::read_to_string(config_path)
+        .await
+        .map_err(|e| ApiFailure::internal(format!("failed to read config: {}", e)))?;
+    Ok(compute_revision(&content))
+}
+
+pub(super) fn compute_revision(content: &str) -> String {
+    let mut hasher = Sha256::new();
+    hasher.update(content.as_bytes());
+    hex::encode(hasher.finalize())
+}
+
+pub(super) async fn load_config_from_disk(config_path: &Path) -> Result<ProxyConfig, ApiFailure> {
+    let config_path = config_path.to_path_buf();
+    tokio::task::spawn_blocking(move || ProxyConfig::load(config_path))
+        .await
+        .map_err(|e| ApiFailure::internal(format!("failed to join config loader: {}", e)))?
+        .map_err(|e| ApiFailure::internal(format!("failed to load config: {}", e)))
+}
+
+pub(super) async fn save_config_to_disk(
+    config_path: &Path,
+    cfg: &ProxyConfig,
+) -> Result<String, ApiFailure> {
+    let serialized = toml::to_string_pretty(cfg)
+        .map_err(|e| ApiFailure::internal(format!("failed to serialize config: {}", e)))?;
+    write_atomic(config_path.to_path_buf(), serialized.clone()).await?;
+    Ok(compute_revision(&serialized))
+}
+
+async fn write_atomic(path: PathBuf, contents: String) -> Result<(), ApiFailure> {
+    tokio::task::spawn_blocking(move || write_atomic_sync(&path, &contents))
+        .await
+        .map_err(|e| ApiFailure::internal(format!("failed to join writer: {}", e)))?
+        .map_err(|e| ApiFailure::internal(format!("failed to write config: {}", e)))
+}
+
+fn write_atomic_sync(path: &Path, contents: &str) -> std::io::Result<()> {
+    let parent = path.parent().unwrap_or_else(|| Path::new("."));
+    std::fs::create_dir_all(parent)?;
+
+    let tmp_name = format!(
+        ".{}.tmp-{}",
+        path.file_name()
+            .and_then(|s| s.to_str())
+            .unwrap_or("config.toml"),
+        rand::random::<u64>()
+    );
+    let tmp_path = parent.join(tmp_name);
+
+    let write_result = (|| {
+        let mut file = std::fs::OpenOptions::new()
+            .create_new(true)
+            .write(true)
+            .open(&tmp_path)?;
+        file.write_all(contents.as_bytes())?;
+        file.sync_all()?;
+        std::fs::rename(&tmp_path, path)?;
+        if let Ok(dir) = std::fs::File::open(parent) {
+            let _ = dir.sync_all();
+        }
+        Ok(())
+    })();
+
+    if write_result.is_err() {
+        let _ = std::fs::remove_file(&tmp_path);
+    }
+    write_result
+}

src/api/events.rs

@@ -0,0 +1,90 @@
+use std::collections::VecDeque;
+use std::sync::Mutex;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use serde::Serialize;
+
+#[derive(Clone, Serialize)]
+pub(super) struct ApiEventRecord {
+    pub(super) seq: u64,
+    pub(super) ts_epoch_secs: u64,
+    pub(super) event_type: String,
+    pub(super) context: String,
+}
+
+#[derive(Clone, Serialize)]
+pub(super) struct ApiEventSnapshot {
+    pub(super) capacity: usize,
+    pub(super) dropped_total: u64,
+    pub(super) events: Vec<ApiEventRecord>,
+}
+
+struct ApiEventsInner {
+    capacity: usize,
+    dropped_total: u64,
+    next_seq: u64,
+    events: VecDeque<ApiEventRecord>,
+}
+
+/// Bounded ring-buffer for control-plane API/runtime events.
+pub(crate) struct ApiEventStore {
+    inner: Mutex<ApiEventsInner>,
+}
+
+impl ApiEventStore {
+    pub(super) fn new(capacity: usize) -> Self {
+        let bounded = capacity.max(16);
+        Self {
+            inner: Mutex::new(ApiEventsInner {
+                capacity: bounded,
+                dropped_total: 0,
+                next_seq: 1,
+                events: VecDeque::with_capacity(bounded),
+            }),
+        }
+    }
+
+    pub(super) fn record(&self, event_type: &str, context: impl Into<String>) {
+        let now_epoch_secs = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .unwrap_or_default()
+            .as_secs();
+        let mut context = context.into();
+        if context.len() > 256 {
+            context.truncate(256);
+        }
+
+        let mut guard = self.inner.lock().expect("api event store mutex poisoned");
+        if guard.events.len() == guard.capacity {
+            guard.events.pop_front();
+            guard.dropped_total = guard.dropped_total.saturating_add(1);
+        }
+        let seq = guard.next_seq;
+        guard.next_seq = guard.next_seq.saturating_add(1);
+        guard.events.push_back(ApiEventRecord {
+            seq,
+            ts_epoch_secs: now_epoch_secs,
+            event_type: event_type.to_string(),
+            context,
+        });
+    }
+
+    pub(super) fn snapshot(&self, limit: usize) -> ApiEventSnapshot {
+        let guard = self.inner.lock().expect("api event store mutex poisoned");
+        let bounded_limit = limit.clamp(1, guard.capacity.max(1));
+        let mut items: Vec<ApiEventRecord> = guard
+            .events
+            .iter()
+            .rev()
+            .take(bounded_limit)
+            .cloned()
+            .collect();
+        items.reverse();
+
+        ApiEventSnapshot {
+            capacity: guard.capacity,
+            dropped_total: guard.dropped_total,
+            events: items,
+        }
+    }
+}

src/api/http_utils.rs

@@ -0,0 +1,91 @@
+use http_body_util::{BodyExt, Full};
+use hyper::StatusCode;
+use hyper::body::{Bytes, Incoming};
+use serde::Serialize;
+use serde::de::DeserializeOwned;
+
+use super::model::{ApiFailure, ErrorBody, ErrorResponse, SuccessResponse};
+
+pub(super) fn success_response<T: Serialize>(
+    status: StatusCode,
+    data: T,
+    revision: String,
+) -> hyper::Response<Full<Bytes>> {
+    let payload = SuccessResponse {
+        ok: true,
+        data,
+        revision,
+    };
+    let body = serde_json::to_vec(&payload).unwrap_or_else(|_| b"{\"ok\":false}".to_vec());
+    hyper::Response::builder()
+        .status(status)
+        .header("content-type", "application/json; charset=utf-8")
+        .body(Full::new(Bytes::from(body)))
+        .unwrap()
+}
+
+pub(super) fn error_response(
+    request_id: u64,
+    failure: ApiFailure,
+) -> hyper::Response<Full<Bytes>> {
+    let payload = ErrorResponse {
+        ok: false,
+        error: ErrorBody {
+            code: failure.code,
+            message: failure.message,
+        },
+        request_id,
+    };
+    let body = serde_json::to_vec(&payload).unwrap_or_else(|_| {
+        format!(
+            "{{\"ok\":false,\"error\":{{\"code\":\"internal_error\",\"message\":\"serialization failed\"}},\"request_id\":{}}}",
+            request_id
+        )
+        .into_bytes()
+    });
+    hyper::Response::builder()
+        .status(failure.status)
+        .header("content-type", "application/json; charset=utf-8")
+        .body(Full::new(Bytes::from(body)))
+        .unwrap()
+}
+
+pub(super) async fn read_json<T: DeserializeOwned>(
+    body: Incoming,
+    limit: usize,
+) -> Result<T, ApiFailure> {
+    let bytes = read_body_with_limit(body, limit).await?;
+    serde_json::from_slice(&bytes).map_err(|_| ApiFailure::bad_request("Invalid JSON body"))
+}
+
+pub(super) async fn read_optional_json<T: DeserializeOwned>(
+    body: Incoming,
+    limit: usize,
+) -> Result<Option<T>, ApiFailure> {
+    let bytes = read_body_with_limit(body, limit).await?;
+    if bytes.is_empty() {
+        return Ok(None);
+    }
+    serde_json::from_slice(&bytes)
+        .map(Some)
+        .map_err(|_| ApiFailure::bad_request("Invalid JSON body"))
+}
+
+async fn read_body_with_limit(body: Incoming, limit: usize) -> Result<Vec<u8>, ApiFailure> {
+    let mut collected = Vec::new();
+    let mut body = body;
+    while let Some(frame_result) = body.frame().await {
+        let frame = frame_result.map_err(|_| ApiFailure::bad_request("Invalid request body"))?;
+        if let Some(chunk) = frame.data_ref() {
+            if collected.len().saturating_add(chunk.len()) > limit {
+                return Err(ApiFailure::new(
+                    StatusCode::PAYLOAD_TOO_LARGE,
+                    "payload_too_large",
+                    format!("Body exceeds {} bytes", limit),
+                ));
+            }
+            collected.extend_from_slice(chunk);
+        }
+    }
+    Ok(collected)
+}

src/api/mod.rs

@@ -0,0 +1,529 @@
+use std::convert::Infallible;
+use std::net::{IpAddr, SocketAddr};
+use std::path::PathBuf;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
+
+use http_body_util::Full;
+use hyper::body::{Bytes, Incoming};
+use hyper::header::AUTHORIZATION;
+use hyper::server::conn::http1;
+use hyper::service::service_fn;
+use hyper::{Method, Request, Response, StatusCode};
+use tokio::net::TcpListener;
+use tokio::sync::{Mutex, watch};
+use tracing::{debug, info, warn};
+
+use crate::config::ProxyConfig;
+use crate::ip_tracker::UserIpTracker;
+use crate::stats::Stats;
+use crate::transport::middle_proxy::MePool;
+use crate::transport::UpstreamManager;
+
+mod config_store;
+mod events;
+mod http_utils;
+mod model;
+mod runtime_edge;
+mod runtime_min;
+mod runtime_stats;
+mod runtime_watch;
+mod runtime_zero;
+mod users;
+
+use config_store::{current_revision, parse_if_match};
+use http_utils::{error_response, read_json, read_optional_json, success_response};
+use events::ApiEventStore;
+use model::{
+    ApiFailure, CreateUserRequest, HealthData, PatchUserRequest, RotateSecretRequest, SummaryData,
+};
+use runtime_edge::{
+    EdgeConnectionsCacheEntry, build_runtime_connections_summary_data,
+    build_runtime_events_recent_data,
+};
+use runtime_min::{
+    build_runtime_me_pool_state_data, build_runtime_me_quality_data, build_runtime_nat_stun_data,
+    build_runtime_upstream_quality_data, build_security_whitelist_data,
+};
+use runtime_stats::{
+    MinimalCacheEntry, build_dcs_data, build_me_writers_data, build_minimal_all_data,
+    build_upstreams_data, build_zero_all_data,
+};
+use runtime_zero::{
+    build_limits_effective_data, build_runtime_gates_data, build_security_posture_data,
+    build_system_info_data,
+};
+use runtime_watch::spawn_runtime_watchers;
+use users::{create_user, delete_user, patch_user, rotate_secret, users_from_config};
+
+pub(super) struct ApiRuntimeState {
+    pub(super) process_started_at_epoch_secs: u64,
+    pub(super) config_reload_count: AtomicU64,
+    pub(super) last_config_reload_epoch_secs: AtomicU64,
+    pub(super) admission_open: AtomicBool,
+}
+
+#[derive(Clone)]
+pub(super) struct ApiShared {
+    pub(super) stats: Arc<Stats>,
+    pub(super) ip_tracker: Arc<UserIpTracker>,
+    pub(super) me_pool: Option<Arc<MePool>>,
+    pub(super) upstream_manager: Arc<UpstreamManager>,
+    pub(super) config_path: PathBuf,
+    pub(super) startup_detected_ip_v4: Option<IpAddr>,
+    pub(super) startup_detected_ip_v6: Option<IpAddr>,
+    pub(super) mutation_lock: Arc<Mutex<()>>,
+    pub(super) minimal_cache: Arc<Mutex<Option<MinimalCacheEntry>>>,
+    pub(super) runtime_edge_connections_cache: Arc<Mutex<Option<EdgeConnectionsCacheEntry>>>,
+    pub(super) runtime_edge_recompute_lock: Arc<Mutex<()>>,
+    pub(super) runtime_events: Arc<ApiEventStore>,
+    pub(super) request_id: Arc<AtomicU64>,
+    pub(super) runtime_state: Arc<ApiRuntimeState>,
+}
+
+impl ApiShared {
+    fn next_request_id(&self) -> u64 {
+        self.request_id.fetch_add(1, Ordering::Relaxed)
+    }
+}
+
+pub async fn serve(
+    listen: SocketAddr,
+    stats: Arc<Stats>,
+    ip_tracker: Arc<UserIpTracker>,
+    me_pool: Option<Arc<MePool>>,
+    upstream_manager: Arc<UpstreamManager>,
+    config_rx: watch::Receiver<Arc<ProxyConfig>>,
+    admission_rx: watch::Receiver<bool>,
+    config_path: PathBuf,
+    startup_detected_ip_v4: Option<IpAddr>,
+    startup_detected_ip_v6: Option<IpAddr>,
+    process_started_at_epoch_secs: u64,
+) {
+    let listener = match TcpListener::bind(listen).await {
+        Ok(listener) => listener,
+        Err(error) => {
+            warn!(
+                error = %error,
+                listen = %listen,
+                "Failed to bind API listener"
+            );
+            return;
+        }
+    };
+
+    info!("API endpoint: http://{}/v1/*", listen);
+
+    let runtime_state = Arc::new(ApiRuntimeState {
+        process_started_at_epoch_secs,
+        config_reload_count: AtomicU64::new(0),
+        last_config_reload_epoch_secs: AtomicU64::new(0),
+        admission_open: AtomicBool::new(*admission_rx.borrow()),
+    });
+
+    let shared = Arc::new(ApiShared {
+        stats,
+        ip_tracker,
+        me_pool,
+        upstream_manager,
+        config_path,
+        startup_detected_ip_v4,
+        startup_detected_ip_v6,
+        mutation_lock: Arc::new(Mutex::new(())),
+        minimal_cache: Arc::new(Mutex::new(None)),
+        runtime_edge_connections_cache: Arc::new(Mutex::new(None)),
+        runtime_edge_recompute_lock: Arc::new(Mutex::new(())),
+        runtime_events: Arc::new(ApiEventStore::new(
+            config_rx.borrow().server.api.runtime_edge_events_capacity,
+        )),
+        request_id: Arc::new(AtomicU64::new(1)),
+        runtime_state: runtime_state.clone(),
+    });
+
+    spawn_runtime_watchers(
+        config_rx.clone(),
+        admission_rx.clone(),
+        runtime_state.clone(),
+        shared.runtime_events.clone(),
+    );
+
+    loop {
+        let (stream, peer) = match listener.accept().await {
+            Ok(v) => v,
+            Err(error) => {
+                warn!(error = %error, "API accept error");
+                continue;
+            }
+        };
+
+        let shared_conn = shared.clone();
+        let config_rx_conn = config_rx.clone();
+        tokio::spawn(async move {
+            let svc = service_fn(move |req: Request<Incoming>| {
+                let shared_req = shared_conn.clone();
+                let config_rx_req = config_rx_conn.clone();
+                async move { handle(req, peer, shared_req, config_rx_req).await }
+            });
+            if let Err(error) = http1::Builder::new()
+                .serve_connection(hyper_util::rt::TokioIo::new(stream), svc)
+                .await
+            {
+                debug!(error = %error, "API connection error");
+            }
+        });
+    }
+}
+
+async fn handle(
+    req: Request<Incoming>,
+    peer: SocketAddr,
+    shared: Arc<ApiShared>,
+    config_rx: watch::Receiver<Arc<ProxyConfig>>,
+) -> Result<Response<Full<Bytes>>, Infallible> {
+    let request_id = shared.next_request_id();
+    let cfg = config_rx.borrow().clone();
+    let api_cfg = &cfg.server.api;
+
+    if !api_cfg.enabled {
+        return Ok(error_response(
+            request_id,
+            ApiFailure::new(
+                StatusCode::SERVICE_UNAVAILABLE,
+                "api_disabled",
+                "API is disabled",
+            ),
+        ));
+    }
+
+    if !api_cfg.whitelist.is_empty()
+        && !api_cfg
+            .whitelist
+            .iter()
+            .any(|net| net.contains(peer.ip()))
+    {
+        return Ok(error_response(
+            request_id,
+            ApiFailure::new(StatusCode::FORBIDDEN, "forbidden", "Source IP is not allowed"),
+        ));
+    }
+
+    if !api_cfg.auth_header.is_empty() {
+        let auth_ok = req
+            .headers()
+            .get(AUTHORIZATION)
+            .and_then(|v| v.to_str().ok())
+            .map(|v| v == api_cfg.auth_header)
+            .unwrap_or(false);
+        if !auth_ok {
+            return Ok(error_response(
+                request_id,
+                ApiFailure::new(
+                    StatusCode::UNAUTHORIZED,
+                    "unauthorized",
+                    "Missing or invalid Authorization header",
+                ),
+            ));
+        }
+    }
+
+    let method = req.method().clone();
+    let path = req.uri().path().to_string();
+    let query = req.uri().query().map(str::to_string);
+    let body_limit = api_cfg.request_body_limit_bytes;
+
+    let result: Result<Response<Full<Bytes>>, ApiFailure> = async {
+        match (method.as_str(), path.as_str()) {
+            ("GET", "/v1/health") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = HealthData {
+                    status: "ok",
+                    read_only: api_cfg.read_only,
+                };
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/system/info") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_system_info_data(shared.as_ref(), cfg.as_ref(), &revision);
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/runtime/gates") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_runtime_gates_data(shared.as_ref(), cfg.as_ref());
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/limits/effective") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_limits_effective_data(cfg.as_ref());
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/security/posture") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_security_posture_data(cfg.as_ref());
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/security/whitelist") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_security_whitelist_data(cfg.as_ref());
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/stats/summary") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = SummaryData {
+                    uptime_seconds: shared.stats.uptime_secs(),
+                    connections_total: shared.stats.get_connects_all(),
+                    connections_bad_total: shared.stats.get_connects_bad(),
+                    handshake_timeouts_total: shared.stats.get_handshake_timeouts(),
+                    configured_users: cfg.access.users.len(),
+                };
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/stats/zero/all") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_zero_all_data(&shared.stats, cfg.access.users.len());
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/stats/upstreams") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_upstreams_data(shared.as_ref(), api_cfg);
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/stats/minimal/all") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_minimal_all_data(shared.as_ref(), api_cfg).await;
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/stats/me-writers") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_me_writers_data(shared.as_ref(), api_cfg).await;
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/stats/dcs") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_dcs_data(shared.as_ref(), api_cfg).await;
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/runtime/me_pool_state") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_runtime_me_pool_state_data(shared.as_ref()).await;
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/runtime/me_quality") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_runtime_me_quality_data(shared.as_ref()).await;
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/runtime/upstream_quality") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_runtime_upstream_quality_data(shared.as_ref()).await;
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/runtime/nat_stun") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_runtime_nat_stun_data(shared.as_ref()).await;
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/runtime/connections/summary") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_runtime_connections_summary_data(shared.as_ref(), cfg.as_ref()).await;
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/runtime/events/recent") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let data = build_runtime_events_recent_data(
+                    shared.as_ref(),
+                    cfg.as_ref(),
+                    query.as_deref(),
+                );
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
+            ("GET", "/v1/stats/users") | ("GET", "/v1/users") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let users = users_from_config(
+                    &cfg,
+                    &shared.stats,
+                    &shared.ip_tracker,
+                    shared.startup_detected_ip_v4,
+                    shared.startup_detected_ip_v6,
+                )
+                .await;
+                Ok(success_response(StatusCode::OK, users, revision))
+            }
+            ("POST", "/v1/users") => {
+                if api_cfg.read_only {
+                    return Ok(error_response(
+                        request_id,
+                        ApiFailure::new(
+                            StatusCode::FORBIDDEN,
+                            "read_only",
+                            "API runs in read-only mode",
+                        ),
+                    ));
+                }
+                let expected_revision = parse_if_match(req.headers());
+                let body = read_json::<CreateUserRequest>(req.into_body(), body_limit).await?;
+                let result = create_user(body, expected_revision, &shared).await;
+                let (data, revision) = match result {
+                    Ok(ok) => ok,
+                    Err(error) => {
+                        shared.runtime_events.record("api.user.create.failed", error.code);
+                        return Err(error);
+                    }
+                };
+                shared
+                    .runtime_events
+                    .record("api.user.create.ok", format!("username={}", data.user.username));
+                Ok(success_response(StatusCode::CREATED, data, revision))
+            }
+            _ => {
+                if let Some(user) = path.strip_prefix("/v1/users/")
+                    && !user.is_empty()
+                    && !user.contains('/')
+                {
+                    if method == Method::GET {
+                        let revision = current_revision(&shared.config_path).await?;
+                        let users = users_from_config(
+                            &cfg,
+                            &shared.stats,
+                            &shared.ip_tracker,
+                            shared.startup_detected_ip_v4,
+                            shared.startup_detected_ip_v6,
+                        )
+                        .await;
+                        if let Some(user_info) = users.into_iter().find(|entry| entry.username == user)
+                        {
+                            return Ok(success_response(StatusCode::OK, user_info, revision));
+                        }
+                        return Ok(error_response(
+                            request_id,
+                            ApiFailure::new(StatusCode::NOT_FOUND, "not_found", "User not found"),
+                        ));
+                    }
+                    if method == Method::PATCH {
+                        if api_cfg.read_only {
+                            return Ok(error_response(
+                                request_id,
+                                ApiFailure::new(
+                                    StatusCode::FORBIDDEN,
+                                    "read_only",
+                                    "API runs in read-only mode",
+                                ),
+                            ));
+                        }
+                        let expected_revision = parse_if_match(req.headers());
+                        let body = read_json::<PatchUserRequest>(req.into_body(), body_limit).await?;
+                        let result = patch_user(user, body, expected_revision, &shared).await;
+                        let (data, revision) = match result {
+                            Ok(ok) => ok,
+                            Err(error) => {
+                                shared.runtime_events.record(
+                                    "api.user.patch.failed",
+                                    format!("username={} code={}", user, error.code),
+                                );
+                                return Err(error);
+                            }
+                        };
+                        shared
+                            .runtime_events
+                            .record("api.user.patch.ok", format!("username={}", data.username));
+                        return Ok(success_response(StatusCode::OK, data, revision));
+                    }
+                    if method == Method::DELETE {
+                        if api_cfg.read_only {
+                            return Ok(error_response(
+                                request_id,
+                                ApiFailure::new(
+                                    StatusCode::FORBIDDEN,
+                                    "read_only",
+                                    "API runs in read-only mode",
+                                ),
+                            ));
+                        }
+                        let expected_revision = parse_if_match(req.headers());
+                        let result = delete_user(user, expected_revision, &shared).await;
+                        let (deleted_user, revision) = match result {
+                            Ok(ok) => ok,
+                            Err(error) => {
+                                shared.runtime_events.record(
+                                    "api.user.delete.failed",
+                                    format!("username={} code={}", user, error.code),
+                                );
+                                return Err(error);
+                            }
+                        };
+                        shared.runtime_events.record(
+                            "api.user.delete.ok",
+                            format!("username={}", deleted_user),
+                        );
+                        return Ok(success_response(StatusCode::OK, deleted_user, revision));
+                    }
+                    if method == Method::POST
+                        && let Some(base_user) = user.strip_suffix("/rotate-secret")
+                        && !base_user.is_empty()
+                        && !base_user.contains('/')
+                    {
+                        if api_cfg.read_only {
+                            return Ok(error_response(
+                                request_id,
+                                ApiFailure::new(
+                                    StatusCode::FORBIDDEN,
+                                    "read_only",
+                                    "API runs in read-only mode",
+                                ),
+                            ));
+                        }
+                        let expected_revision = parse_if_match(req.headers());
+                        let body =
+                            read_optional_json::<RotateSecretRequest>(req.into_body(), body_limit)
+                                .await?;
+                        let result = rotate_secret(
+                            base_user,
+                            body.unwrap_or_default(),
+                            expected_revision,
+                            &shared,
+                        )
+                        .await;
+                        let (data, revision) = match result {
+                            Ok(ok) => ok,
+                            Err(error) => {
+                                shared.runtime_events.record(
+                                    "api.user.rotate_secret.failed",
+                                    format!("username={} code={}", base_user, error.code),
+                                );
+                                return Err(error);
+                            }
+                        };
+                        shared.runtime_events.record(
+                            "api.user.rotate_secret.ok",
+                            format!("username={}", base_user),
+                        );
+                        return Ok(success_response(StatusCode::OK, data, revision));
+                    }
+                    if method == Method::POST {
+                        return Ok(error_response(
+                            request_id,
+                            ApiFailure::new(StatusCode::NOT_FOUND, "not_found", "Route not found"),
+                        ));
+                    }
+                    return Ok(error_response(
+                        request_id,
+                        ApiFailure::new(
+                            StatusCode::METHOD_NOT_ALLOWED,
+                            "method_not_allowed",
+                            "Unsupported HTTP method for this route",
+                        ),
+                    ));
+                }
+                Ok(error_response(
+                    request_id,
+                    ApiFailure::new(StatusCode::NOT_FOUND, "not_found", "Route not found"),
+                ))
+            }
+        }
+    }
+    .await;
+
+    match result {
+        Ok(resp) => Ok(resp),
+        Err(error) => Ok(error_response(request_id, error)),
+    }
+}

src/api/model.rs

@@ -0,0 +1,458 @@
+use std::net::IpAddr;
+
+use chrono::{DateTime, Utc};
+use hyper::StatusCode;
+use rand::Rng;
+use serde::{Deserialize, Serialize};
+
+const MAX_USERNAME_LEN: usize = 64;
+
+#[derive(Debug)]
+pub(super) struct ApiFailure {
+    pub(super) status: StatusCode,
+    pub(super) code: &'static str,
+    pub(super) message: String,
+}
+
+impl ApiFailure {
+    pub(super) fn new(status: StatusCode, code: &'static str, message: impl Into<String>) -> Self {
+        Self {
+            status,
+            code,
+            message: message.into(),
+        }
+    }
+
+    pub(super) fn internal(message: impl Into<String>) -> Self {
+        Self::new(StatusCode::INTERNAL_SERVER_ERROR, "internal_error", message)
+    }
+
+    pub(super) fn bad_request(message: impl Into<String>) -> Self {
+        Self::new(StatusCode::BAD_REQUEST, "bad_request", message)
+    }
+}
+
+#[derive(Serialize)]
+pub(super) struct ErrorBody {
+    pub(super) code: &'static str,
+    pub(super) message: String,
+}
+
+#[derive(Serialize)]
+pub(super) struct ErrorResponse {
+    pub(super) ok: bool,
+    pub(super) error: ErrorBody,
+    pub(super) request_id: u64,
+}
+
+#[derive(Serialize)]
+pub(super) struct SuccessResponse<T> {
+    pub(super) ok: bool,
+    pub(super) data: T,
+    pub(super) revision: String,
+}
+
+#[derive(Serialize)]
+pub(super) struct HealthData {
+    pub(super) status: &'static str,
+    pub(super) read_only: bool,
+}
+
+#[derive(Serialize)]
+pub(super) struct SummaryData {
+    pub(super) uptime_seconds: f64,
+    pub(super) connections_total: u64,
+    pub(super) connections_bad_total: u64,
+    pub(super) handshake_timeouts_total: u64,
+    pub(super) configured_users: usize,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct ZeroCodeCount {
+    pub(super) code: i32,
+    pub(super) total: u64,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct ZeroCoreData {
+    pub(super) uptime_seconds: f64,
+    pub(super) connections_total: u64,
+    pub(super) connections_bad_total: u64,
+    pub(super) handshake_timeouts_total: u64,
+    pub(super) configured_users: usize,
+    pub(super) telemetry_core_enabled: bool,
+    pub(super) telemetry_user_enabled: bool,
+    pub(super) telemetry_me_level: String,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct ZeroUpstreamData {
+    pub(super) connect_attempt_total: u64,
+    pub(super) connect_success_total: u64,
+    pub(super) connect_fail_total: u64,
+    pub(super) connect_failfast_hard_error_total: u64,
+    pub(super) connect_attempts_bucket_1: u64,
+    pub(super) connect_attempts_bucket_2: u64,
+    pub(super) connect_attempts_bucket_3_4: u64,
+    pub(super) connect_attempts_bucket_gt_4: u64,
+    pub(super) connect_duration_success_bucket_le_100ms: u64,
+    pub(super) connect_duration_success_bucket_101_500ms: u64,
+    pub(super) connect_duration_success_bucket_501_1000ms: u64,
+    pub(super) connect_duration_success_bucket_gt_1000ms: u64,
+    pub(super) connect_duration_fail_bucket_le_100ms: u64,
+    pub(super) connect_duration_fail_bucket_101_500ms: u64,
+    pub(super) connect_duration_fail_bucket_501_1000ms: u64,
+    pub(super) connect_duration_fail_bucket_gt_1000ms: u64,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct UpstreamDcStatus {
+    pub(super) dc: i16,
+    pub(super) latency_ema_ms: Option<f64>,
+    pub(super) ip_preference: &'static str,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct UpstreamStatus {
+    pub(super) upstream_id: usize,
+    pub(super) route_kind: &'static str,
+    pub(super) address: String,
+    pub(super) weight: u16,
+    pub(super) scopes: String,
+    pub(super) healthy: bool,
+    pub(super) fails: u32,
+    pub(super) last_check_age_secs: u64,
+    pub(super) effective_latency_ms: Option<f64>,
+    pub(super) dc: Vec<UpstreamDcStatus>,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct UpstreamSummaryData {
+    pub(super) configured_total: usize,
+    pub(super) healthy_total: usize,
+    pub(super) unhealthy_total: usize,
+    pub(super) direct_total: usize,
+    pub(super) socks4_total: usize,
+    pub(super) socks5_total: usize,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct UpstreamsData {
+    pub(super) enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    pub(super) zero: ZeroUpstreamData,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) summary: Option<UpstreamSummaryData>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) upstreams: Option<Vec<UpstreamStatus>>,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct ZeroMiddleProxyData {
+    pub(super) keepalive_sent_total: u64,
+    pub(super) keepalive_failed_total: u64,
+    pub(super) keepalive_pong_total: u64,
+    pub(super) keepalive_timeout_total: u64,
+    pub(super) rpc_proxy_req_signal_sent_total: u64,
+    pub(super) rpc_proxy_req_signal_failed_total: u64,
+    pub(super) rpc_proxy_req_signal_skipped_no_meta_total: u64,
+    pub(super) rpc_proxy_req_signal_response_total: u64,
+    pub(super) rpc_proxy_req_signal_close_sent_total: u64,
+    pub(super) reconnect_attempt_total: u64,
+    pub(super) reconnect_success_total: u64,
+    pub(super) handshake_reject_total: u64,
+    pub(super) handshake_error_codes: Vec<ZeroCodeCount>,
+    pub(super) reader_eof_total: u64,
+    pub(super) idle_close_by_peer_total: u64,
+    pub(super) route_drop_no_conn_total: u64,
+    pub(super) route_drop_channel_closed_total: u64,
+    pub(super) route_drop_queue_full_total: u64,
+    pub(super) route_drop_queue_full_base_total: u64,
+    pub(super) route_drop_queue_full_high_total: u64,
+    pub(super) socks_kdf_strict_reject_total: u64,
+    pub(super) socks_kdf_compat_fallback_total: u64,
+    pub(super) endpoint_quarantine_total: u64,
+    pub(super) kdf_drift_total: u64,
+    pub(super) kdf_port_only_drift_total: u64,
+    pub(super) hardswap_pending_reuse_total: u64,
+    pub(super) hardswap_pending_ttl_expired_total: u64,
+    pub(super) single_endpoint_outage_enter_total: u64,
+    pub(super) single_endpoint_outage_exit_total: u64,
+    pub(super) single_endpoint_outage_reconnect_attempt_total: u64,
+    pub(super) single_endpoint_outage_reconnect_success_total: u64,
+    pub(super) single_endpoint_quarantine_bypass_total: u64,
+    pub(super) single_endpoint_shadow_rotate_total: u64,
+    pub(super) single_endpoint_shadow_rotate_skipped_quarantine_total: u64,
+    pub(super) floor_mode_switch_total: u64,
+    pub(super) floor_mode_switch_static_to_adaptive_total: u64,
+    pub(super) floor_mode_switch_adaptive_to_static_total: u64,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct ZeroPoolData {
+    pub(super) pool_swap_total: u64,
+    pub(super) pool_drain_active: u64,
+    pub(super) pool_force_close_total: u64,
+    pub(super) pool_stale_pick_total: u64,
+    pub(super) writer_removed_total: u64,
+    pub(super) writer_removed_unexpected_total: u64,
+    pub(super) refill_triggered_total: u64,
+    pub(super) refill_skipped_inflight_total: u64,
+    pub(super) refill_failed_total: u64,
+    pub(super) writer_restored_same_endpoint_total: u64,
+    pub(super) writer_restored_fallback_total: u64,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct ZeroDesyncData {
+    pub(super) secure_padding_invalid_total: u64,
+    pub(super) desync_total: u64,
+    pub(super) desync_full_logged_total: u64,
+    pub(super) desync_suppressed_total: u64,
+    pub(super) desync_frames_bucket_0: u64,
+    pub(super) desync_frames_bucket_1_2: u64,
+    pub(super) desync_frames_bucket_3_10: u64,
+    pub(super) desync_frames_bucket_gt_10: u64,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct ZeroAllData {
+    pub(super) generated_at_epoch_secs: u64,
+    pub(super) core: ZeroCoreData,
+    pub(super) upstream: ZeroUpstreamData,
+    pub(super) middle_proxy: ZeroMiddleProxyData,
+    pub(super) pool: ZeroPoolData,
+    pub(super) desync: ZeroDesyncData,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct MeWritersSummary {
+    pub(super) configured_dc_groups: usize,
+    pub(super) configured_endpoints: usize,
+    pub(super) available_endpoints: usize,
+    pub(super) available_pct: f64,
+    pub(super) required_writers: usize,
+    pub(super) alive_writers: usize,
+    pub(super) coverage_pct: f64,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct MeWriterStatus {
+    pub(super) writer_id: u64,
+    pub(super) dc: Option<i16>,
+    pub(super) endpoint: String,
+    pub(super) generation: u64,
+    pub(super) state: &'static str,
+    pub(super) draining: bool,
+    pub(super) degraded: bool,
+    pub(super) bound_clients: usize,
+    pub(super) idle_for_secs: Option<u64>,
+    pub(super) rtt_ema_ms: Option<f64>,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct MeWritersData {
+    pub(super) middle_proxy_enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    pub(super) summary: MeWritersSummary,
+    pub(super) writers: Vec<MeWriterStatus>,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct DcStatus {
+    pub(super) dc: i16,
+    pub(super) endpoints: Vec<String>,
+    pub(super) available_endpoints: usize,
+    pub(super) available_pct: f64,
+    pub(super) required_writers: usize,
+    pub(super) floor_min: usize,
+    pub(super) floor_target: usize,
+    pub(super) floor_max: usize,
+    pub(super) floor_capped: bool,
+    pub(super) alive_writers: usize,
+    pub(super) coverage_pct: f64,
+    pub(super) rtt_ms: Option<f64>,
+    pub(super) load: usize,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct DcStatusData {
+    pub(super) middle_proxy_enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    pub(super) dcs: Vec<DcStatus>,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct MinimalQuarantineData {
+    pub(super) endpoint: String,
+    pub(super) remaining_ms: u64,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct MinimalDcPathData {
+    pub(super) dc: i16,
+    pub(super) ip_preference: Option<&'static str>,
+    pub(super) selected_addr_v4: Option<String>,
+    pub(super) selected_addr_v6: Option<String>,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct MinimalMeRuntimeData {
+    pub(super) active_generation: u64,
+    pub(super) warm_generation: u64,
+    pub(super) pending_hardswap_generation: u64,
+    pub(super) pending_hardswap_age_secs: Option<u64>,
+    pub(super) hardswap_enabled: bool,
+    pub(super) floor_mode: &'static str,
+    pub(super) adaptive_floor_idle_secs: u64,
+    pub(super) adaptive_floor_min_writers_single_endpoint: u8,
+    pub(super) adaptive_floor_min_writers_multi_endpoint: u8,
+    pub(super) adaptive_floor_recover_grace_secs: u64,
+    pub(super) adaptive_floor_writers_per_core_total: u16,
+    pub(super) adaptive_floor_cpu_cores_override: u16,
+    pub(super) adaptive_floor_max_extra_writers_single_per_core: u16,
+    pub(super) adaptive_floor_max_extra_writers_multi_per_core: u16,
+    pub(super) adaptive_floor_cpu_cores_detected: u32,
+    pub(super) adaptive_floor_cpu_cores_effective: u32,
+    pub(super) adaptive_floor_global_cap_raw: u64,
+    pub(super) adaptive_floor_global_cap_effective: u64,
+    pub(super) adaptive_floor_target_writers_total: u64,
+    pub(super) me_keepalive_enabled: bool,
+    pub(super) me_keepalive_interval_secs: u64,
+    pub(super) me_keepalive_jitter_secs: u64,
+    pub(super) me_keepalive_payload_random: bool,
+    pub(super) rpc_proxy_req_every_secs: u64,
+    pub(super) me_reconnect_max_concurrent_per_dc: u32,
+    pub(super) me_reconnect_backoff_base_ms: u64,
+    pub(super) me_reconnect_backoff_cap_ms: u64,
+    pub(super) me_reconnect_fast_retry_count: u32,
+    pub(super) me_pool_drain_ttl_secs: u64,
+    pub(super) me_pool_force_close_secs: u64,
+    pub(super) me_pool_min_fresh_ratio: f32,
+    pub(super) me_bind_stale_mode: &'static str,
+    pub(super) me_bind_stale_ttl_secs: u64,
+    pub(super) me_single_endpoint_shadow_writers: u8,
+    pub(super) me_single_endpoint_outage_mode_enabled: bool,
+    pub(super) me_single_endpoint_outage_disable_quarantine: bool,
+    pub(super) me_single_endpoint_outage_backoff_min_ms: u64,
+    pub(super) me_single_endpoint_outage_backoff_max_ms: u64,
+    pub(super) me_single_endpoint_shadow_rotate_every_secs: u64,
+    pub(super) me_deterministic_writer_sort: bool,
+    pub(super) me_socks_kdf_policy: &'static str,
+    pub(super) quarantined_endpoints_total: usize,
+    pub(super) quarantined_endpoints: Vec<MinimalQuarantineData>,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct MinimalAllPayload {
+    pub(super) me_writers: MeWritersData,
+    pub(super) dcs: DcStatusData,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) me_runtime: Option<MinimalMeRuntimeData>,
+    pub(super) network_path: Vec<MinimalDcPathData>,
+}
+
+#[derive(Serialize, Clone)]
+pub(super) struct MinimalAllData {
+    pub(super) enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) data: Option<MinimalAllPayload>,
+}
+
+#[derive(Serialize)]
+pub(super) struct UserLinks {
+    pub(super) classic: Vec<String>,
+    pub(super) secure: Vec<String>,
+    pub(super) tls: Vec<String>,
+}
+
+#[derive(Serialize)]
+pub(super) struct UserInfo {
+    pub(super) username: String,
+    pub(super) user_ad_tag: Option<String>,
+    pub(super) max_tcp_conns: Option<usize>,
+    pub(super) expiration_rfc3339: Option<String>,
+    pub(super) data_quota_bytes: Option<u64>,
+    pub(super) max_unique_ips: Option<usize>,
+    pub(super) current_connections: u64,
+    pub(super) active_unique_ips: usize,
+    pub(super) active_unique_ips_list: Vec<IpAddr>,
+    pub(super) recent_unique_ips: usize,
+    pub(super) recent_unique_ips_list: Vec<IpAddr>,
+    pub(super) total_octets: u64,
+    pub(super) links: UserLinks,
+}
+
+#[derive(Serialize)]
+pub(super) struct CreateUserResponse {
+    pub(super) user: UserInfo,
+    pub(super) secret: String,
+}
+
+#[derive(Deserialize)]
+pub(super) struct CreateUserRequest {
+    pub(super) username: String,
+    pub(super) secret: Option<String>,
+    pub(super) user_ad_tag: Option<String>,
+    pub(super) max_tcp_conns: Option<usize>,
+    pub(super) expiration_rfc3339: Option<String>,
+    pub(super) data_quota_bytes: Option<u64>,
+    pub(super) max_unique_ips: Option<usize>,
+}
+
+#[derive(Deserialize)]
+pub(super) struct PatchUserRequest {
+    pub(super) secret: Option<String>,
+    pub(super) user_ad_tag: Option<String>,
+    pub(super) max_tcp_conns: Option<usize>,
+    pub(super) expiration_rfc3339: Option<String>,
+    pub(super) data_quota_bytes: Option<u64>,
+    pub(super) max_unique_ips: Option<usize>,
+}
+
+#[derive(Default, Deserialize)]
+pub(super) struct RotateSecretRequest {
+    pub(super) secret: Option<String>,
+}
+
+pub(super) fn parse_optional_expiration(
+    value: Option<&str>,
+) -> Result<Option<DateTime<Utc>>, ApiFailure> {
+    let Some(raw) = value else {
+        return Ok(None);
+    };
+    let parsed = DateTime::parse_from_rfc3339(raw)
+        .map_err(|_| ApiFailure::bad_request("expiration_rfc3339 must be valid RFC3339"))?;
+    Ok(Some(parsed.with_timezone(&Utc)))
+}
+
+pub(super) fn is_valid_user_secret(secret: &str) -> bool {
+    secret.len() == 32 && secret.chars().all(|c| c.is_ascii_hexdigit())
+}
+
+pub(super) fn is_valid_ad_tag(tag: &str) -> bool {
+    tag.len() == 32 && tag.chars().all(|c| c.is_ascii_hexdigit())
+}
+
+pub(super) fn is_valid_username(user: &str) -> bool {
+    !user.is_empty()
+        && user.len() <= MAX_USERNAME_LEN
+        && user
+            .chars()
+            .all(|ch| ch.is_ascii_alphanumeric() || matches!(ch, '_' | '-' | '.'))
+}
+
+pub(super) fn random_user_secret() -> String {
+    let mut bytes = [0u8; 16];
+    rand::rng().fill(&mut bytes);
+    hex::encode(bytes)
+}

src/api/runtime_edge.rs

@@ -0,0 +1,294 @@
+use std::cmp::Reverse;
+use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
+
+use serde::Serialize;
+
+use crate::config::ProxyConfig;
+
+use super::ApiShared;
+use super::events::ApiEventRecord;
+
+const FEATURE_DISABLED_REASON: &str = "feature_disabled";
+const SOURCE_UNAVAILABLE_REASON: &str = "source_unavailable";
+const EVENTS_DEFAULT_LIMIT: usize = 50;
+const EVENTS_MAX_LIMIT: usize = 1000;
+
+#[derive(Clone, Serialize)]
+pub(super) struct RuntimeEdgeConnectionUserData {
+    pub(super) username: String,
+    pub(super) current_connections: u64,
+    pub(super) total_octets: u64,
+}
+
+#[derive(Clone, Serialize)]
+pub(super) struct RuntimeEdgeConnectionTotalsData {
+    pub(super) current_connections: u64,
+    pub(super) current_connections_me: u64,
+    pub(super) current_connections_direct: u64,
+    pub(super) active_users: usize,
+}
+
+#[derive(Clone, Serialize)]
+pub(super) struct RuntimeEdgeConnectionTopData {
+    pub(super) limit: usize,
+    pub(super) by_connections: Vec<RuntimeEdgeConnectionUserData>,
+    pub(super) by_throughput: Vec<RuntimeEdgeConnectionUserData>,
+}
+
+#[derive(Clone, Serialize)]
+pub(super) struct RuntimeEdgeConnectionCacheData {
+    pub(super) ttl_ms: u64,
+    pub(super) served_from_cache: bool,
+    pub(super) stale_cache_used: bool,
+}
+
+#[derive(Clone, Serialize)]
+pub(super) struct RuntimeEdgeConnectionTelemetryData {
+    pub(super) user_enabled: bool,
+    pub(super) throughput_is_cumulative: bool,
+}
+
+#[derive(Clone, Serialize)]
+pub(super) struct RuntimeEdgeConnectionsSummaryPayload {
+    pub(super) cache: RuntimeEdgeConnectionCacheData,
+    pub(super) totals: RuntimeEdgeConnectionTotalsData,
+    pub(super) top: RuntimeEdgeConnectionTopData,
+    pub(super) telemetry: RuntimeEdgeConnectionTelemetryData,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeEdgeConnectionsSummaryData {
+    pub(super) enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) data: Option<RuntimeEdgeConnectionsSummaryPayload>,
+}
+
+#[derive(Clone)]
+pub(crate) struct EdgeConnectionsCacheEntry {
+    pub(super) expires_at: Instant,
+    pub(super) payload: RuntimeEdgeConnectionsSummaryPayload,
+    pub(super) generated_at_epoch_secs: u64,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeEdgeEventsPayload {
+    pub(super) capacity: usize,
+    pub(super) dropped_total: u64,
+    pub(super) events: Vec<ApiEventRecord>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeEdgeEventsData {
+    pub(super) enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) data: Option<RuntimeEdgeEventsPayload>,
+}
+
+pub(super) async fn build_runtime_connections_summary_data(
+    shared: &ApiShared,
+    cfg: &ProxyConfig,
+) -> RuntimeEdgeConnectionsSummaryData {
+    let now_epoch_secs = now_epoch_secs();
+    let api_cfg = &cfg.server.api;
+    if !api_cfg.runtime_edge_enabled {
+        return RuntimeEdgeConnectionsSummaryData {
+            enabled: false,
+            reason: Some(FEATURE_DISABLED_REASON),
+            generated_at_epoch_secs: now_epoch_secs,
+            data: None,
+        };
+    }
+
+    let (generated_at_epoch_secs, payload) = match get_connections_payload_cached(
+        shared,
+        api_cfg.runtime_edge_cache_ttl_ms,
+        api_cfg.runtime_edge_top_n,
+    )
+    .await
+    {
+        Some(v) => v,
+        None => {
+            return RuntimeEdgeConnectionsSummaryData {
+                enabled: true,
+                reason: Some(SOURCE_UNAVAILABLE_REASON),
+                generated_at_epoch_secs: now_epoch_secs,
+                data: None,
+            };
+        }
+    };
+
+    RuntimeEdgeConnectionsSummaryData {
+        enabled: true,
+        reason: None,
+        generated_at_epoch_secs,
+        data: Some(payload),
+    }
+}
+
+pub(super) fn build_runtime_events_recent_data(
+    shared: &ApiShared,
+    cfg: &ProxyConfig,
+    query: Option<&str>,
+) -> RuntimeEdgeEventsData {
+    let now_epoch_secs = now_epoch_secs();
+    let api_cfg = &cfg.server.api;
+    if !api_cfg.runtime_edge_enabled {
+        return RuntimeEdgeEventsData {
+            enabled: false,
+            reason: Some(FEATURE_DISABLED_REASON),
+            generated_at_epoch_secs: now_epoch_secs,
+            data: None,
+        };
+    }
+
+    let limit = parse_recent_events_limit(query, EVENTS_DEFAULT_LIMIT, EVENTS_MAX_LIMIT);
+    let snapshot = shared.runtime_events.snapshot(limit);
+
+    RuntimeEdgeEventsData {
+        enabled: true,
+        reason: None,
+        generated_at_epoch_secs: now_epoch_secs,
+        data: Some(RuntimeEdgeEventsPayload {
+            capacity: snapshot.capacity,
+            dropped_total: snapshot.dropped_total,
+            events: snapshot.events,
+        }),
+    }
+}
+
+async fn get_connections_payload_cached(
+    shared: &ApiShared,
+    cache_ttl_ms: u64,
+    top_n: usize,
+) -> Option<(u64, RuntimeEdgeConnectionsSummaryPayload)> {
+    if cache_ttl_ms > 0 {
+        let now = Instant::now();
+        let cached = shared.runtime_edge_connections_cache.lock().await.clone();
+        if let Some(entry) = cached
+            && now < entry.expires_at
+        {
+            let mut payload = entry.payload;
+            payload.cache.served_from_cache = true;
+            payload.cache.stale_cache_used = false;
+            return Some((entry.generated_at_epoch_secs, payload));
+        }
+    }
+
+    let Ok(_guard) = shared.runtime_edge_recompute_lock.try_lock() else {
+        let cached = shared.runtime_edge_connections_cache.lock().await.clone();
+        if let Some(entry) = cached {
+            let mut payload = entry.payload;
+            payload.cache.served_from_cache = true;
+            payload.cache.stale_cache_used = true;
+            return Some((entry.generated_at_epoch_secs, payload));
+        }
+        return None;
+    };
+
+    let generated_at_epoch_secs = now_epoch_secs();
+    let payload = recompute_connections_payload(shared, cache_ttl_ms, top_n).await;
+
+    if cache_ttl_ms > 0 {
+        let entry = EdgeConnectionsCacheEntry {
+            expires_at: Instant::now() + Duration::from_millis(cache_ttl_ms),
+            payload: payload.clone(),
+            generated_at_epoch_secs,
+        };
+        *shared.runtime_edge_connections_cache.lock().await = Some(entry);
+    }
+
+    Some((generated_at_epoch_secs, payload))
+}
+
+async fn recompute_connections_payload(
+    shared: &ApiShared,
+    cache_ttl_ms: u64,
+    top_n: usize,
+) -> RuntimeEdgeConnectionsSummaryPayload {
+    let mut rows = Vec::<RuntimeEdgeConnectionUserData>::new();
+    let mut active_users = 0usize;
+    for entry in shared.stats.iter_user_stats() {
+        let user_stats = entry.value();
+        let current_connections = user_stats
+            .curr_connects
+            .load(std::sync::atomic::Ordering::Relaxed);
+        let total_octets = user_stats
+            .octets_from_client
+            .load(std::sync::atomic::Ordering::Relaxed)
+            .saturating_add(
+                user_stats
+                    .octets_to_client
+                    .load(std::sync::atomic::Ordering::Relaxed),
+            );
+        if current_connections > 0 {
+            active_users = active_users.saturating_add(1);
+        }
+        rows.push(RuntimeEdgeConnectionUserData {
+            username: entry.key().clone(),
+            current_connections,
+            total_octets,
+        });
+    }
+
+    let limit = top_n.max(1);
+    let mut by_connections = rows.clone();
+    by_connections.sort_by_key(|row| (Reverse(row.current_connections), row.username.clone()));
+    by_connections.truncate(limit);
+
+    let mut by_throughput = rows;
+    by_throughput.sort_by_key(|row| (Reverse(row.total_octets), row.username.clone()));
+    by_throughput.truncate(limit);
+
+    let telemetry = shared.stats.telemetry_policy();
+    RuntimeEdgeConnectionsSummaryPayload {
+        cache: RuntimeEdgeConnectionCacheData {
+            ttl_ms: cache_ttl_ms,
+            served_from_cache: false,
+            stale_cache_used: false,
+        },
+        totals: RuntimeEdgeConnectionTotalsData {
+            current_connections: shared.stats.get_current_connections_total(),
+            current_connections_me: shared.stats.get_current_connections_me(),
+            current_connections_direct: shared.stats.get_current_connections_direct(),
+            active_users,
+        },
+        top: RuntimeEdgeConnectionTopData {
+            limit,
+            by_connections,
+            by_throughput,
+        },
+        telemetry: RuntimeEdgeConnectionTelemetryData {
+            user_enabled: telemetry.user_enabled,
+            throughput_is_cumulative: true,
+        },
+    }
+}
+
+fn parse_recent_events_limit(query: Option<&str>, default_limit: usize, max_limit: usize) -> usize {
+    let Some(query) = query else {
+        return default_limit;
+    };
+    for pair in query.split('&') {
+        let mut split = pair.splitn(2, '=');
+        if split.next() == Some("limit")
+            && let Some(raw) = split.next()
+            && let Ok(parsed) = raw.parse::<usize>()
+        {
+            return parsed.clamp(1, max_limit);
+        }
+    }
+    default_limit
+}
+
+fn now_epoch_secs() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}

src/api/runtime_min.rs

@@ -0,0 +1,534 @@
+use std::collections::BTreeSet;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use serde::Serialize;
+
+use crate::config::ProxyConfig;
+
+use super::ApiShared;
+
+const SOURCE_UNAVAILABLE_REASON: &str = "source_unavailable";
+
+#[derive(Serialize)]
+pub(super) struct SecurityWhitelistData {
+    pub(super) generated_at_epoch_secs: u64,
+    pub(super) enabled: bool,
+    pub(super) entries_total: usize,
+    pub(super) entries: Vec<String>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMePoolStateGenerationData {
+    pub(super) active_generation: u64,
+    pub(super) warm_generation: u64,
+    pub(super) pending_hardswap_generation: u64,
+    pub(super) pending_hardswap_age_secs: Option<u64>,
+    pub(super) draining_generations: Vec<u64>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMePoolStateHardswapData {
+    pub(super) enabled: bool,
+    pub(super) pending: bool,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMePoolStateWriterContourData {
+    pub(super) warm: usize,
+    pub(super) active: usize,
+    pub(super) draining: usize,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMePoolStateWriterHealthData {
+    pub(super) healthy: usize,
+    pub(super) degraded: usize,
+    pub(super) draining: usize,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMePoolStateWriterData {
+    pub(super) total: usize,
+    pub(super) alive_non_draining: usize,
+    pub(super) draining: usize,
+    pub(super) degraded: usize,
+    pub(super) contour: RuntimeMePoolStateWriterContourData,
+    pub(super) health: RuntimeMePoolStateWriterHealthData,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMePoolStateRefillDcData {
+    pub(super) dc: i16,
+    pub(super) family: &'static str,
+    pub(super) inflight: usize,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMePoolStateRefillData {
+    pub(super) inflight_endpoints_total: usize,
+    pub(super) inflight_dc_total: usize,
+    pub(super) by_dc: Vec<RuntimeMePoolStateRefillDcData>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMePoolStatePayload {
+    pub(super) generations: RuntimeMePoolStateGenerationData,
+    pub(super) hardswap: RuntimeMePoolStateHardswapData,
+    pub(super) writers: RuntimeMePoolStateWriterData,
+    pub(super) refill: RuntimeMePoolStateRefillData,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMePoolStateData {
+    pub(super) enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) data: Option<RuntimeMePoolStatePayload>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMeQualityCountersData {
+    pub(super) idle_close_by_peer_total: u64,
+    pub(super) reader_eof_total: u64,
+    pub(super) kdf_drift_total: u64,
+    pub(super) kdf_port_only_drift_total: u64,
+    pub(super) reconnect_attempt_total: u64,
+    pub(super) reconnect_success_total: u64,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMeQualityRouteDropData {
+    pub(super) no_conn_total: u64,
+    pub(super) channel_closed_total: u64,
+    pub(super) queue_full_total: u64,
+    pub(super) queue_full_base_total: u64,
+    pub(super) queue_full_high_total: u64,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMeQualityDcRttData {
+    pub(super) dc: i16,
+    pub(super) rtt_ema_ms: Option<f64>,
+    pub(super) alive_writers: usize,
+    pub(super) required_writers: usize,
+    pub(super) coverage_pct: f64,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMeQualityPayload {
+    pub(super) counters: RuntimeMeQualityCountersData,
+    pub(super) route_drops: RuntimeMeQualityRouteDropData,
+    pub(super) dc_rtt: Vec<RuntimeMeQualityDcRttData>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeMeQualityData {
+    pub(super) enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) data: Option<RuntimeMeQualityPayload>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeUpstreamQualityPolicyData {
+    pub(super) connect_retry_attempts: u32,
+    pub(super) connect_retry_backoff_ms: u64,
+    pub(super) connect_budget_ms: u64,
+    pub(super) unhealthy_fail_threshold: u32,
+    pub(super) connect_failfast_hard_errors: bool,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeUpstreamQualityCountersData {
+    pub(super) connect_attempt_total: u64,
+    pub(super) connect_success_total: u64,
+    pub(super) connect_fail_total: u64,
+    pub(super) connect_failfast_hard_error_total: u64,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeUpstreamQualitySummaryData {
+    pub(super) configured_total: usize,
+    pub(super) healthy_total: usize,
+    pub(super) unhealthy_total: usize,
+    pub(super) direct_total: usize,
+    pub(super) socks4_total: usize,
+    pub(super) socks5_total: usize,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeUpstreamQualityDcData {
+    pub(super) dc: i16,
+    pub(super) latency_ema_ms: Option<f64>,
+    pub(super) ip_preference: &'static str,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeUpstreamQualityUpstreamData {
+    pub(super) upstream_id: usize,
+    pub(super) route_kind: &'static str,
+    pub(super) address: String,
+    pub(super) weight: u16,
+    pub(super) scopes: String,
+    pub(super) healthy: bool,
+    pub(super) fails: u32,
+    pub(super) last_check_age_secs: u64,
+    pub(super) effective_latency_ms: Option<f64>,
+    pub(super) dc: Vec<RuntimeUpstreamQualityDcData>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeUpstreamQualityData {
+    pub(super) enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    pub(super) policy: RuntimeUpstreamQualityPolicyData,
+    pub(super) counters: RuntimeUpstreamQualityCountersData,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) summary: Option<RuntimeUpstreamQualitySummaryData>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) upstreams: Option<Vec<RuntimeUpstreamQualityUpstreamData>>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeNatStunReflectionData {
+    pub(super) addr: String,
+    pub(super) age_secs: u64,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeNatStunFlagsData {
+    pub(super) nat_probe_enabled: bool,
+    pub(super) nat_probe_disabled_runtime: bool,
+    pub(super) nat_probe_attempts: u8,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeNatStunServersData {
+    pub(super) configured: Vec<String>,
+    pub(super) live: Vec<String>,
+    pub(super) live_total: usize,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeNatStunReflectionBlockData {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) v4: Option<RuntimeNatStunReflectionData>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) v6: Option<RuntimeNatStunReflectionData>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeNatStunPayload {
+    pub(super) flags: RuntimeNatStunFlagsData,
+    pub(super) servers: RuntimeNatStunServersData,
+    pub(super) reflection: RuntimeNatStunReflectionBlockData,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) stun_backoff_remaining_ms: Option<u64>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeNatStunData {
+    pub(super) enabled: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) generated_at_epoch_secs: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) data: Option<RuntimeNatStunPayload>,
+}
+
+pub(super) fn build_security_whitelist_data(cfg: &ProxyConfig) -> SecurityWhitelistData {
+    let entries = cfg
+        .server
+        .api
+        .whitelist
+        .iter()
+        .map(ToString::to_string)
+        .collect::<Vec<_>>();
+    SecurityWhitelistData {
+        generated_at_epoch_secs: now_epoch_secs(),
+        enabled: !entries.is_empty(),
+        entries_total: entries.len(),
+        entries,
+    }
+}
+
+pub(super) async fn build_runtime_me_pool_state_data(shared: &ApiShared) -> RuntimeMePoolStateData {
+    let now_epoch_secs = now_epoch_secs();
+    let Some(pool) = &shared.me_pool else {
+        return RuntimeMePoolStateData {
+            enabled: false,
+            reason: Some(SOURCE_UNAVAILABLE_REASON),
+            generated_at_epoch_secs: now_epoch_secs,
+            data: None,
+        };
+    };
+
+    let status = pool.api_status_snapshot().await;
+    let runtime = pool.api_runtime_snapshot().await;
+    let refill = pool.api_refill_snapshot().await;
+
+    let mut draining_generations = BTreeSet::<u64>::new();
+    let mut contour_warm = 0usize;
+    let mut contour_active = 0usize;
+    let mut contour_draining = 0usize;
+    let mut draining = 0usize;
+    let mut degraded = 0usize;
+    let mut healthy = 0usize;
+
+    for writer in &status.writers {
+        if writer.draining {
+            draining_generations.insert(writer.generation);
+            draining += 1;
+        }
+        if writer.degraded && !writer.draining {
+            degraded += 1;
+        }
+        if !writer.degraded && !writer.draining {
+            healthy += 1;
+        }
+        match writer.state {
+            "warm" => contour_warm += 1,
+            "active" => contour_active += 1,
+            _ => contour_draining += 1,
+        }
+    }
+
+    RuntimeMePoolStateData {
+        enabled: true,
+        reason: None,
+        generated_at_epoch_secs: status.generated_at_epoch_secs,
+        data: Some(RuntimeMePoolStatePayload {
+            generations: RuntimeMePoolStateGenerationData {
+                active_generation: runtime.active_generation,
+                warm_generation: runtime.warm_generation,
+                pending_hardswap_generation: runtime.pending_hardswap_generation,
+                pending_hardswap_age_secs: runtime.pending_hardswap_age_secs,
+                draining_generations: draining_generations.into_iter().collect(),
+            },
+            hardswap: RuntimeMePoolStateHardswapData {
+                enabled: runtime.hardswap_enabled,
+                pending: runtime.pending_hardswap_generation != 0,
+            },
+            writers: RuntimeMePoolStateWriterData {
+                total: status.writers.len(),
+                alive_non_draining: status.writers.len().saturating_sub(draining),
+                draining,
+                degraded,
+                contour: RuntimeMePoolStateWriterContourData {
+                    warm: contour_warm,
+                    active: contour_active,
+                    draining: contour_draining,
+                },
+                health: RuntimeMePoolStateWriterHealthData {
+                    healthy,
+                    degraded,
+                    draining,
+                },
+            },
+            refill: RuntimeMePoolStateRefillData {
+                inflight_endpoints_total: refill.inflight_endpoints_total,
+                inflight_dc_total: refill.inflight_dc_total,
+                by_dc: refill
+                    .by_dc
+                    .into_iter()
+                    .map(|entry| RuntimeMePoolStateRefillDcData {
+                        dc: entry.dc,
+                        family: entry.family,
+                        inflight: entry.inflight,
+                    })
+                    .collect(),
+            },
+        }),
+    }
+}
+
+pub(super) async fn build_runtime_me_quality_data(shared: &ApiShared) -> RuntimeMeQualityData {
+    let now_epoch_secs = now_epoch_secs();
+    let Some(pool) = &shared.me_pool else {
+        return RuntimeMeQualityData {
+            enabled: false,
+            reason: Some(SOURCE_UNAVAILABLE_REASON),
+            generated_at_epoch_secs: now_epoch_secs,
+            data: None,
+        };
+    };
+
+    let status = pool.api_status_snapshot().await;
+    RuntimeMeQualityData {
+        enabled: true,
+        reason: None,
+        generated_at_epoch_secs: status.generated_at_epoch_secs,
+        data: Some(RuntimeMeQualityPayload {
+            counters: RuntimeMeQualityCountersData {
+                idle_close_by_peer_total: shared.stats.get_me_idle_close_by_peer_total(),
+                reader_eof_total: shared.stats.get_me_reader_eof_total(),
+                kdf_drift_total: shared.stats.get_me_kdf_drift_total(),
+                kdf_port_only_drift_total: shared.stats.get_me_kdf_port_only_drift_total(),
+                reconnect_attempt_total: shared.stats.get_me_reconnect_attempts(),
+                reconnect_success_total: shared.stats.get_me_reconnect_success(),
+            },
+            route_drops: RuntimeMeQualityRouteDropData {
+                no_conn_total: shared.stats.get_me_route_drop_no_conn(),
+                channel_closed_total: shared.stats.get_me_route_drop_channel_closed(),
+                queue_full_total: shared.stats.get_me_route_drop_queue_full(),
+                queue_full_base_total: shared.stats.get_me_route_drop_queue_full_base(),
+                queue_full_high_total: shared.stats.get_me_route_drop_queue_full_high(),
+            },
+            dc_rtt: status
+                .dcs
+                .into_iter()
+                .map(|dc| RuntimeMeQualityDcRttData {
+                    dc: dc.dc,
+                    rtt_ema_ms: dc.rtt_ms,
+                    alive_writers: dc.alive_writers,
+                    required_writers: dc.required_writers,
+                    coverage_pct: dc.coverage_pct,
+                })
+                .collect(),
+        }),
+    }
+}
+
+pub(super) async fn build_runtime_upstream_quality_data(
+    shared: &ApiShared,
+) -> RuntimeUpstreamQualityData {
+    let generated_at_epoch_secs = now_epoch_secs();
+    let policy = shared.upstream_manager.api_policy_snapshot();
+    let counters = RuntimeUpstreamQualityCountersData {
+        connect_attempt_total: shared.stats.get_upstream_connect_attempt_total(),
+        connect_success_total: shared.stats.get_upstream_connect_success_total(),
+        connect_fail_total: shared.stats.get_upstream_connect_fail_total(),
+        connect_failfast_hard_error_total: shared.stats.get_upstream_connect_failfast_hard_error_total(),
+    };
+
+    let Some(snapshot) = shared.upstream_manager.try_api_snapshot() else {
+        return RuntimeUpstreamQualityData {
+            enabled: false,
+            reason: Some(SOURCE_UNAVAILABLE_REASON),
+            generated_at_epoch_secs,
+            policy: RuntimeUpstreamQualityPolicyData {
+                connect_retry_attempts: policy.connect_retry_attempts,
+                connect_retry_backoff_ms: policy.connect_retry_backoff_ms,
+                connect_budget_ms: policy.connect_budget_ms,
+                unhealthy_fail_threshold: policy.unhealthy_fail_threshold,
+                connect_failfast_hard_errors: policy.connect_failfast_hard_errors,
+            },
+            counters,
+            summary: None,
+            upstreams: None,
+        };
+    };
+
+    RuntimeUpstreamQualityData {
+        enabled: true,
+        reason: None,
+        generated_at_epoch_secs,
+        policy: RuntimeUpstreamQualityPolicyData {
+            connect_retry_attempts: policy.connect_retry_attempts,
+            connect_retry_backoff_ms: policy.connect_retry_backoff_ms,
+            connect_budget_ms: policy.connect_budget_ms,
+            unhealthy_fail_threshold: policy.unhealthy_fail_threshold,
+            connect_failfast_hard_errors: policy.connect_failfast_hard_errors,
+        },
+        counters,
+        summary: Some(RuntimeUpstreamQualitySummaryData {
+            configured_total: snapshot.summary.configured_total,
+            healthy_total: snapshot.summary.healthy_total,
+            unhealthy_total: snapshot.summary.unhealthy_total,
+            direct_total: snapshot.summary.direct_total,
+            socks4_total: snapshot.summary.socks4_total,
+            socks5_total: snapshot.summary.socks5_total,
+        }),
+        upstreams: Some(
+            snapshot
+                .upstreams
+                .into_iter()
+                .map(|upstream| RuntimeUpstreamQualityUpstreamData {
+                    upstream_id: upstream.upstream_id,
+                    route_kind: match upstream.route_kind {
+                        crate::transport::UpstreamRouteKind::Direct => "direct",
+                        crate::transport::UpstreamRouteKind::Socks4 => "socks4",
+                        crate::transport::UpstreamRouteKind::Socks5 => "socks5",
+                    },
+                    address: upstream.address,
+                    weight: upstream.weight,
+                    scopes: upstream.scopes,
+                    healthy: upstream.healthy,
+                    fails: upstream.fails,
+                    last_check_age_secs: upstream.last_check_age_secs,
+                    effective_latency_ms: upstream.effective_latency_ms,
+                    dc: upstream
+                        .dc
+                        .into_iter()
+                        .map(|dc| RuntimeUpstreamQualityDcData {
+                            dc: dc.dc,
+                            latency_ema_ms: dc.latency_ema_ms,
+                            ip_preference: match dc.ip_preference {
+                                crate::transport::upstream::IpPreference::Unknown => "unknown",
+                                crate::transport::upstream::IpPreference::PreferV6 => "prefer_v6",
+                                crate::transport::upstream::IpPreference::PreferV4 => "prefer_v4",
+                                crate::transport::upstream::IpPreference::BothWork => "both_work",
+                                crate::transport::upstream::IpPreference::Unavailable => "unavailable",
+                            },
+                        })
+                        .collect(),
+                })
+                .collect(),
+        ),
+    }
+}
+
+pub(super) async fn build_runtime_nat_stun_data(shared: &ApiShared) -> RuntimeNatStunData {
+    let now_epoch_secs = now_epoch_secs();
+    let Some(pool) = &shared.me_pool else {
+        return RuntimeNatStunData {
+            enabled: false,
+            reason: Some(SOURCE_UNAVAILABLE_REASON),
+            generated_at_epoch_secs: now_epoch_secs,
+            data: None,
+        };
+    };
+
+    let snapshot = pool.api_nat_stun_snapshot().await;
+    RuntimeNatStunData {
+        enabled: true,
+        reason: None,
+        generated_at_epoch_secs: now_epoch_secs,
+        data: Some(RuntimeNatStunPayload {
+            flags: RuntimeNatStunFlagsData {
+                nat_probe_enabled: snapshot.nat_probe_enabled,
+                nat_probe_disabled_runtime: snapshot.nat_probe_disabled_runtime,
+                nat_probe_attempts: snapshot.nat_probe_attempts,
+            },
+            servers: RuntimeNatStunServersData {
+                configured: snapshot.configured_servers,
+                live: snapshot.live_servers.clone(),
+                live_total: snapshot.live_servers.len(),
+            },
+            reflection: RuntimeNatStunReflectionBlockData {
+                v4: snapshot.reflection_v4.map(|entry| RuntimeNatStunReflectionData {
+                    addr: entry.addr.to_string(),
+                    age_secs: entry.age_secs,
+                }),
+                v6: snapshot.reflection_v6.map(|entry| RuntimeNatStunReflectionData {
+                    addr: entry.addr.to_string(),
+                    age_secs: entry.age_secs,
+                }),
+            },
+            stun_backoff_remaining_ms: snapshot.stun_backoff_remaining_ms,
+        }),
+    }
+}
+
+fn now_epoch_secs() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}

src/api/runtime_stats.rs

@@ -0,0 +1,502 @@
+use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
+
+use crate::config::ApiConfig;
+use crate::stats::Stats;
+use crate::transport::upstream::IpPreference;
+use crate::transport::UpstreamRouteKind;
+
+use super::ApiShared;
+use super::model::{
+    DcStatus, DcStatusData, MeWriterStatus, MeWritersData, MeWritersSummary, MinimalAllData,
+    MinimalAllPayload, MinimalDcPathData, MinimalMeRuntimeData, MinimalQuarantineData,
+    UpstreamDcStatus, UpstreamStatus, UpstreamSummaryData, UpstreamsData, ZeroAllData,
+    ZeroCodeCount, ZeroCoreData, ZeroDesyncData, ZeroMiddleProxyData, ZeroPoolData,
+    ZeroUpstreamData,
+};
+
+const FEATURE_DISABLED_REASON: &str = "feature_disabled";
+const SOURCE_UNAVAILABLE_REASON: &str = "source_unavailable";
+
+#[derive(Clone)]
+pub(crate) struct MinimalCacheEntry {
+    pub(super) expires_at: Instant,
+    pub(super) payload: MinimalAllPayload,
+    pub(super) generated_at_epoch_secs: u64,
+}
+
+pub(super) fn build_zero_all_data(stats: &Stats, configured_users: usize) -> ZeroAllData {
+    let telemetry = stats.telemetry_policy();
+    let handshake_error_codes = stats
+        .get_me_handshake_error_code_counts()
+        .into_iter()
+        .map(|(code, total)| ZeroCodeCount { code, total })
+        .collect();
+
+    ZeroAllData {
+        generated_at_epoch_secs: now_epoch_secs(),
+        core: ZeroCoreData {
+            uptime_seconds: stats.uptime_secs(),
+            connections_total: stats.get_connects_all(),
+            connections_bad_total: stats.get_connects_bad(),
+            handshake_timeouts_total: stats.get_handshake_timeouts(),
+            configured_users,
+            telemetry_core_enabled: telemetry.core_enabled,
+            telemetry_user_enabled: telemetry.user_enabled,
+            telemetry_me_level: telemetry.me_level.to_string(),
+        },
+        upstream: build_zero_upstream_data(stats),
+        middle_proxy: ZeroMiddleProxyData {
+            keepalive_sent_total: stats.get_me_keepalive_sent(),
+            keepalive_failed_total: stats.get_me_keepalive_failed(),
+            keepalive_pong_total: stats.get_me_keepalive_pong(),
+            keepalive_timeout_total: stats.get_me_keepalive_timeout(),
+            rpc_proxy_req_signal_sent_total: stats.get_me_rpc_proxy_req_signal_sent_total(),
+            rpc_proxy_req_signal_failed_total: stats.get_me_rpc_proxy_req_signal_failed_total(),
+            rpc_proxy_req_signal_skipped_no_meta_total: stats
+                .get_me_rpc_proxy_req_signal_skipped_no_meta_total(),
+            rpc_proxy_req_signal_response_total: stats.get_me_rpc_proxy_req_signal_response_total(),
+            rpc_proxy_req_signal_close_sent_total: stats
+                .get_me_rpc_proxy_req_signal_close_sent_total(),
+            reconnect_attempt_total: stats.get_me_reconnect_attempts(),
+            reconnect_success_total: stats.get_me_reconnect_success(),
+            handshake_reject_total: stats.get_me_handshake_reject_total(),
+            handshake_error_codes,
+            reader_eof_total: stats.get_me_reader_eof_total(),
+            idle_close_by_peer_total: stats.get_me_idle_close_by_peer_total(),
+            route_drop_no_conn_total: stats.get_me_route_drop_no_conn(),
+            route_drop_channel_closed_total: stats.get_me_route_drop_channel_closed(),
+            route_drop_queue_full_total: stats.get_me_route_drop_queue_full(),
+            route_drop_queue_full_base_total: stats.get_me_route_drop_queue_full_base(),
+            route_drop_queue_full_high_total: stats.get_me_route_drop_queue_full_high(),
+            socks_kdf_strict_reject_total: stats.get_me_socks_kdf_strict_reject(),
+            socks_kdf_compat_fallback_total: stats.get_me_socks_kdf_compat_fallback(),
+            endpoint_quarantine_total: stats.get_me_endpoint_quarantine_total(),
+            kdf_drift_total: stats.get_me_kdf_drift_total(),
+            kdf_port_only_drift_total: stats.get_me_kdf_port_only_drift_total(),
+            hardswap_pending_reuse_total: stats.get_me_hardswap_pending_reuse_total(),
+            hardswap_pending_ttl_expired_total: stats.get_me_hardswap_pending_ttl_expired_total(),
+            single_endpoint_outage_enter_total: stats.get_me_single_endpoint_outage_enter_total(),
+            single_endpoint_outage_exit_total: stats.get_me_single_endpoint_outage_exit_total(),
+            single_endpoint_outage_reconnect_attempt_total: stats
+                .get_me_single_endpoint_outage_reconnect_attempt_total(),
+            single_endpoint_outage_reconnect_success_total: stats
+                .get_me_single_endpoint_outage_reconnect_success_total(),
+            single_endpoint_quarantine_bypass_total: stats
+                .get_me_single_endpoint_quarantine_bypass_total(),
+            single_endpoint_shadow_rotate_total: stats.get_me_single_endpoint_shadow_rotate_total(),
+            single_endpoint_shadow_rotate_skipped_quarantine_total: stats
+                .get_me_single_endpoint_shadow_rotate_skipped_quarantine_total(),
+            floor_mode_switch_total: stats.get_me_floor_mode_switch_total(),
+            floor_mode_switch_static_to_adaptive_total: stats
+                .get_me_floor_mode_switch_static_to_adaptive_total(),
+            floor_mode_switch_adaptive_to_static_total: stats
+                .get_me_floor_mode_switch_adaptive_to_static_total(),
+        },
+        pool: ZeroPoolData {
+            pool_swap_total: stats.get_pool_swap_total(),
+            pool_drain_active: stats.get_pool_drain_active(),
+            pool_force_close_total: stats.get_pool_force_close_total(),
+            pool_stale_pick_total: stats.get_pool_stale_pick_total(),
+            writer_removed_total: stats.get_me_writer_removed_total(),
+            writer_removed_unexpected_total: stats.get_me_writer_removed_unexpected_total(),
+            refill_triggered_total: stats.get_me_refill_triggered_total(),
+            refill_skipped_inflight_total: stats.get_me_refill_skipped_inflight_total(),
+            refill_failed_total: stats.get_me_refill_failed_total(),
+            writer_restored_same_endpoint_total: stats.get_me_writer_restored_same_endpoint_total(),
+            writer_restored_fallback_total: stats.get_me_writer_restored_fallback_total(),
+        },
+        desync: ZeroDesyncData {
+            secure_padding_invalid_total: stats.get_secure_padding_invalid(),
+            desync_total: stats.get_desync_total(),
+            desync_full_logged_total: stats.get_desync_full_logged(),
+            desync_suppressed_total: stats.get_desync_suppressed(),
+            desync_frames_bucket_0: stats.get_desync_frames_bucket_0(),
+            desync_frames_bucket_1_2: stats.get_desync_frames_bucket_1_2(),
+            desync_frames_bucket_3_10: stats.get_desync_frames_bucket_3_10(),
+            desync_frames_bucket_gt_10: stats.get_desync_frames_bucket_gt_10(),
+        },
+    }
+}
+
+fn build_zero_upstream_data(stats: &Stats) -> ZeroUpstreamData {
+    ZeroUpstreamData {
+        connect_attempt_total: stats.get_upstream_connect_attempt_total(),
+        connect_success_total: stats.get_upstream_connect_success_total(),
+        connect_fail_total: stats.get_upstream_connect_fail_total(),
+        connect_failfast_hard_error_total: stats.get_upstream_connect_failfast_hard_error_total(),
+        connect_attempts_bucket_1: stats.get_upstream_connect_attempts_bucket_1(),
+        connect_attempts_bucket_2: stats.get_upstream_connect_attempts_bucket_2(),
+        connect_attempts_bucket_3_4: stats.get_upstream_connect_attempts_bucket_3_4(),
+        connect_attempts_bucket_gt_4: stats.get_upstream_connect_attempts_bucket_gt_4(),
+        connect_duration_success_bucket_le_100ms: stats
+            .get_upstream_connect_duration_success_bucket_le_100ms(),
+        connect_duration_success_bucket_101_500ms: stats
+            .get_upstream_connect_duration_success_bucket_101_500ms(),
+        connect_duration_success_bucket_501_1000ms: stats
+            .get_upstream_connect_duration_success_bucket_501_1000ms(),
+        connect_duration_success_bucket_gt_1000ms: stats
+            .get_upstream_connect_duration_success_bucket_gt_1000ms(),
+        connect_duration_fail_bucket_le_100ms: stats.get_upstream_connect_duration_fail_bucket_le_100ms(),
+        connect_duration_fail_bucket_101_500ms: stats
+            .get_upstream_connect_duration_fail_bucket_101_500ms(),
+        connect_duration_fail_bucket_501_1000ms: stats
+            .get_upstream_connect_duration_fail_bucket_501_1000ms(),
+        connect_duration_fail_bucket_gt_1000ms: stats
+            .get_upstream_connect_duration_fail_bucket_gt_1000ms(),
+    }
+}
+
+pub(super) fn build_upstreams_data(shared: &ApiShared, api_cfg: &ApiConfig) -> UpstreamsData {
+    let generated_at_epoch_secs = now_epoch_secs();
+    let zero = build_zero_upstream_data(&shared.stats);
+    if !api_cfg.minimal_runtime_enabled {
+        return UpstreamsData {
+            enabled: false,
+            reason: Some(FEATURE_DISABLED_REASON),
+            generated_at_epoch_secs,
+            zero,
+            summary: None,
+            upstreams: None,
+        };
+    }
+
+    let Some(snapshot) = shared.upstream_manager.try_api_snapshot() else {
+        return UpstreamsData {
+            enabled: true,
+            reason: Some(SOURCE_UNAVAILABLE_REASON),
+            generated_at_epoch_secs,
+            zero,
+            summary: None,
+            upstreams: None,
+        };
+    };
+
+    let summary = UpstreamSummaryData {
+        configured_total: snapshot.summary.configured_total,
+        healthy_total: snapshot.summary.healthy_total,
+        unhealthy_total: snapshot.summary.unhealthy_total,
+        direct_total: snapshot.summary.direct_total,
+        socks4_total: snapshot.summary.socks4_total,
+        socks5_total: snapshot.summary.socks5_total,
+    };
+    let upstreams = snapshot
+        .upstreams
+        .into_iter()
+        .map(|upstream| UpstreamStatus {
+            upstream_id: upstream.upstream_id,
+            route_kind: map_route_kind(upstream.route_kind),
+            address: upstream.address,
+            weight: upstream.weight,
+            scopes: upstream.scopes,
+            healthy: upstream.healthy,
+            fails: upstream.fails,
+            last_check_age_secs: upstream.last_check_age_secs,
+            effective_latency_ms: upstream.effective_latency_ms,
+            dc: upstream
+                .dc
+                .into_iter()
+                .map(|dc| UpstreamDcStatus {
+                    dc: dc.dc,
+                    latency_ema_ms: dc.latency_ema_ms,
+                    ip_preference: map_ip_preference(dc.ip_preference),
+                })
+                .collect(),
+        })
+        .collect();
+
+    UpstreamsData {
+        enabled: true,
+        reason: None,
+        generated_at_epoch_secs,
+        zero,
+        summary: Some(summary),
+        upstreams: Some(upstreams),
+    }
+}
+
+pub(super) async fn build_minimal_all_data(
+    shared: &ApiShared,
+    api_cfg: &ApiConfig,
+) -> MinimalAllData {
+    let now = now_epoch_secs();
+    if !api_cfg.minimal_runtime_enabled {
+        return MinimalAllData {
+            enabled: false,
+            reason: Some(FEATURE_DISABLED_REASON),
+            generated_at_epoch_secs: now,
+            data: None,
+        };
+    }
+
+    let Some((generated_at_epoch_secs, payload)) =
+        get_minimal_payload_cached(shared, api_cfg.minimal_runtime_cache_ttl_ms).await
+    else {
+        return MinimalAllData {
+            enabled: true,
+            reason: Some(SOURCE_UNAVAILABLE_REASON),
+            generated_at_epoch_secs: now,
+            data: Some(MinimalAllPayload {
+                me_writers: disabled_me_writers(now, SOURCE_UNAVAILABLE_REASON),
+                dcs: disabled_dcs(now, SOURCE_UNAVAILABLE_REASON),
+                me_runtime: None,
+                network_path: Vec::new(),
+            }),
+        };
+    };
+
+    MinimalAllData {
+        enabled: true,
+        reason: None,
+        generated_at_epoch_secs,
+        data: Some(payload),
+    }
+}
+
+pub(super) async fn build_me_writers_data(
+    shared: &ApiShared,
+    api_cfg: &ApiConfig,
+) -> MeWritersData {
+    let now = now_epoch_secs();
+    if !api_cfg.minimal_runtime_enabled {
+        return disabled_me_writers(now, FEATURE_DISABLED_REASON);
+    }
+
+    let Some((_, payload)) =
+        get_minimal_payload_cached(shared, api_cfg.minimal_runtime_cache_ttl_ms).await
+    else {
+        return disabled_me_writers(now, SOURCE_UNAVAILABLE_REASON);
+    };
+    payload.me_writers
+}
+
+pub(super) async fn build_dcs_data(shared: &ApiShared, api_cfg: &ApiConfig) -> DcStatusData {
+    let now = now_epoch_secs();
+    if !api_cfg.minimal_runtime_enabled {
+        return disabled_dcs(now, FEATURE_DISABLED_REASON);
+    }
+
+    let Some((_, payload)) =
+        get_minimal_payload_cached(shared, api_cfg.minimal_runtime_cache_ttl_ms).await
+    else {
+        return disabled_dcs(now, SOURCE_UNAVAILABLE_REASON);
+    };
+    payload.dcs
+}
+
+async fn get_minimal_payload_cached(
+    shared: &ApiShared,
+    cache_ttl_ms: u64,
+) -> Option<(u64, MinimalAllPayload)> {
+    if cache_ttl_ms > 0 {
+        let now = Instant::now();
+        let cached = shared.minimal_cache.lock().await.clone();
+        if let Some(entry) = cached
+            && now < entry.expires_at
+        {
+            return Some((entry.generated_at_epoch_secs, entry.payload));
+        }
+    }
+
+    let pool = shared.me_pool.as_ref()?;
+    let status = pool.api_status_snapshot().await;
+    let runtime = pool.api_runtime_snapshot().await;
+    let generated_at_epoch_secs = status.generated_at_epoch_secs;
+
+    let me_writers = MeWritersData {
+        middle_proxy_enabled: true,
+        reason: None,
+        generated_at_epoch_secs,
+        summary: MeWritersSummary {
+            configured_dc_groups: status.configured_dc_groups,
+            configured_endpoints: status.configured_endpoints,
+            available_endpoints: status.available_endpoints,
+            available_pct: status.available_pct,
+            required_writers: status.required_writers,
+            alive_writers: status.alive_writers,
+            coverage_pct: status.coverage_pct,
+        },
+        writers: status
+            .writers
+            .into_iter()
+            .map(|entry| MeWriterStatus {
+                writer_id: entry.writer_id,
+                dc: entry.dc,
+                endpoint: entry.endpoint.to_string(),
+                generation: entry.generation,
+                state: entry.state,
+                draining: entry.draining,
+                degraded: entry.degraded,
+                bound_clients: entry.bound_clients,
+                idle_for_secs: entry.idle_for_secs,
+                rtt_ema_ms: entry.rtt_ema_ms,
+            })
+            .collect(),
+    };
+    let dcs = DcStatusData {
+        middle_proxy_enabled: true,
+        reason: None,
+        generated_at_epoch_secs,
+        dcs: status
+            .dcs
+            .into_iter()
+            .map(|entry| DcStatus {
+                dc: entry.dc,
+                endpoints: entry
+                    .endpoints
+                    .into_iter()
+                    .map(|value| value.to_string())
+                    .collect(),
+                available_endpoints: entry.available_endpoints,
+                available_pct: entry.available_pct,
+                required_writers: entry.required_writers,
+                floor_min: entry.floor_min,
+                floor_target: entry.floor_target,
+                floor_max: entry.floor_max,
+                floor_capped: entry.floor_capped,
+                alive_writers: entry.alive_writers,
+                coverage_pct: entry.coverage_pct,
+                rtt_ms: entry.rtt_ms,
+                load: entry.load,
+            })
+            .collect(),
+    };
+    let me_runtime = MinimalMeRuntimeData {
+        active_generation: runtime.active_generation,
+        warm_generation: runtime.warm_generation,
+        pending_hardswap_generation: runtime.pending_hardswap_generation,
+        pending_hardswap_age_secs: runtime.pending_hardswap_age_secs,
+        hardswap_enabled: runtime.hardswap_enabled,
+        floor_mode: runtime.floor_mode,
+        adaptive_floor_idle_secs: runtime.adaptive_floor_idle_secs,
+        adaptive_floor_min_writers_single_endpoint: runtime
+            .adaptive_floor_min_writers_single_endpoint,
+        adaptive_floor_min_writers_multi_endpoint: runtime
+            .adaptive_floor_min_writers_multi_endpoint,
+        adaptive_floor_recover_grace_secs: runtime.adaptive_floor_recover_grace_secs,
+        adaptive_floor_writers_per_core_total: runtime
+            .adaptive_floor_writers_per_core_total,
+        adaptive_floor_cpu_cores_override: runtime.adaptive_floor_cpu_cores_override,
+        adaptive_floor_max_extra_writers_single_per_core: runtime
+            .adaptive_floor_max_extra_writers_single_per_core,
+        adaptive_floor_max_extra_writers_multi_per_core: runtime
+            .adaptive_floor_max_extra_writers_multi_per_core,
+        adaptive_floor_cpu_cores_detected: runtime.adaptive_floor_cpu_cores_detected,
+        adaptive_floor_cpu_cores_effective: runtime.adaptive_floor_cpu_cores_effective,
+        adaptive_floor_global_cap_raw: runtime.adaptive_floor_global_cap_raw,
+        adaptive_floor_global_cap_effective: runtime.adaptive_floor_global_cap_effective,
+        adaptive_floor_target_writers_total: runtime.adaptive_floor_target_writers_total,
+        me_keepalive_enabled: runtime.me_keepalive_enabled,
+        me_keepalive_interval_secs: runtime.me_keepalive_interval_secs,
+        me_keepalive_jitter_secs: runtime.me_keepalive_jitter_secs,
+        me_keepalive_payload_random: runtime.me_keepalive_payload_random,
+        rpc_proxy_req_every_secs: runtime.rpc_proxy_req_every_secs,
+        me_reconnect_max_concurrent_per_dc: runtime.me_reconnect_max_concurrent_per_dc,
+        me_reconnect_backoff_base_ms: runtime.me_reconnect_backoff_base_ms,
+        me_reconnect_backoff_cap_ms: runtime.me_reconnect_backoff_cap_ms,
+        me_reconnect_fast_retry_count: runtime.me_reconnect_fast_retry_count,
+        me_pool_drain_ttl_secs: runtime.me_pool_drain_ttl_secs,
+        me_pool_force_close_secs: runtime.me_pool_force_close_secs,
+        me_pool_min_fresh_ratio: runtime.me_pool_min_fresh_ratio,
+        me_bind_stale_mode: runtime.me_bind_stale_mode,
+        me_bind_stale_ttl_secs: runtime.me_bind_stale_ttl_secs,
+        me_single_endpoint_shadow_writers: runtime.me_single_endpoint_shadow_writers,
+        me_single_endpoint_outage_mode_enabled: runtime.me_single_endpoint_outage_mode_enabled,
+        me_single_endpoint_outage_disable_quarantine: runtime
+            .me_single_endpoint_outage_disable_quarantine,
+        me_single_endpoint_outage_backoff_min_ms: runtime.me_single_endpoint_outage_backoff_min_ms,
+        me_single_endpoint_outage_backoff_max_ms: runtime.me_single_endpoint_outage_backoff_max_ms,
+        me_single_endpoint_shadow_rotate_every_secs: runtime
+            .me_single_endpoint_shadow_rotate_every_secs,
+        me_deterministic_writer_sort: runtime.me_deterministic_writer_sort,
+        me_socks_kdf_policy: runtime.me_socks_kdf_policy,
+        quarantined_endpoints_total: runtime.quarantined_endpoints.len(),
+        quarantined_endpoints: runtime
+            .quarantined_endpoints
+            .into_iter()
+            .map(|entry| MinimalQuarantineData {
+                endpoint: entry.endpoint.to_string(),
+                remaining_ms: entry.remaining_ms,
+            })
+            .collect(),
+    };
+    let network_path = runtime
+        .network_path
+        .into_iter()
+        .map(|entry| MinimalDcPathData {
+            dc: entry.dc,
+            ip_preference: entry.ip_preference,
+            selected_addr_v4: entry.selected_addr_v4.map(|value| value.to_string()),
+            selected_addr_v6: entry.selected_addr_v6.map(|value| value.to_string()),
+        })
+        .collect();
+
+    let payload = MinimalAllPayload {
+        me_writers,
+        dcs,
+        me_runtime: Some(me_runtime),
+        network_path,
+    };
+
+    if cache_ttl_ms > 0 {
+        let entry = MinimalCacheEntry {
+            expires_at: Instant::now() + Duration::from_millis(cache_ttl_ms),
+            payload: payload.clone(),
+            generated_at_epoch_secs,
+        };
+        *shared.minimal_cache.lock().await = Some(entry);
+    }
+
+    Some((generated_at_epoch_secs, payload))
+}
+
+fn disabled_me_writers(now_epoch_secs: u64, reason: &'static str) -> MeWritersData {
+    MeWritersData {
+        middle_proxy_enabled: false,
+        reason: Some(reason),
+        generated_at_epoch_secs: now_epoch_secs,
+        summary: MeWritersSummary {
+            configured_dc_groups: 0,
+            configured_endpoints: 0,
+            available_endpoints: 0,
+            available_pct: 0.0,
+            required_writers: 0,
+            alive_writers: 0,
+            coverage_pct: 0.0,
+        },
+        writers: Vec::new(),
+    }
+}
+
+fn disabled_dcs(now_epoch_secs: u64, reason: &'static str) -> DcStatusData {
+    DcStatusData {
+        middle_proxy_enabled: false,
+        reason: Some(reason),
+        generated_at_epoch_secs: now_epoch_secs,
+        dcs: Vec::new(),
+    }
+}
+
+fn map_route_kind(value: UpstreamRouteKind) -> &'static str {
+    match value {
+        UpstreamRouteKind::Direct => "direct",
+        UpstreamRouteKind::Socks4 => "socks4",
+        UpstreamRouteKind::Socks5 => "socks5",
+    }
+}
+
+fn map_ip_preference(value: IpPreference) -> &'static str {
+    match value {
+        IpPreference::Unknown => "unknown",
+        IpPreference::PreferV6 => "prefer_v6",
+        IpPreference::PreferV4 => "prefer_v4",
+        IpPreference::BothWork => "both_work",
+        IpPreference::Unavailable => "unavailable",
+    }
+}
+
+fn now_epoch_secs() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}

src/api/runtime_watch.rs

@@ -0,0 +1,66 @@
+use std::sync::Arc;
+use std::sync::atomic::Ordering;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use tokio::sync::watch;
+
+use crate::config::ProxyConfig;
+
+use super::ApiRuntimeState;
+use super::events::ApiEventStore;
+
+pub(super) fn spawn_runtime_watchers(
+    config_rx: watch::Receiver<Arc<ProxyConfig>>,
+    admission_rx: watch::Receiver<bool>,
+    runtime_state: Arc<ApiRuntimeState>,
+    runtime_events: Arc<ApiEventStore>,
+) {
+    let mut config_rx_reload = config_rx;
+    let runtime_state_reload = runtime_state.clone();
+    let runtime_events_reload = runtime_events.clone();
+    tokio::spawn(async move {
+        loop {
+            if config_rx_reload.changed().await.is_err() {
+                break;
+            }
+            runtime_state_reload
+                .config_reload_count
+                .fetch_add(1, Ordering::Relaxed);
+            runtime_state_reload
+                .last_config_reload_epoch_secs
+                .store(now_epoch_secs(), Ordering::Relaxed);
+            runtime_events_reload.record("config.reload.applied", "config receiver updated");
+        }
+    });
+
+    let mut admission_rx_watch = admission_rx;
+    tokio::spawn(async move {
+        runtime_state
+            .admission_open
+            .store(*admission_rx_watch.borrow(), Ordering::Relaxed);
+        runtime_events.record(
+            "admission.state",
+            format!("accepting_new_connections={}", *admission_rx_watch.borrow()),
+        );
+        loop {
+            if admission_rx_watch.changed().await.is_err() {
+                break;
+            }
+            let admission_open = *admission_rx_watch.borrow();
+            runtime_state
+                .admission_open
+                .store(admission_open, Ordering::Relaxed);
+            runtime_events.record(
+                "admission.state",
+                format!("accepting_new_connections={}", admission_open),
+            );
+        }
+    });
+}
+
+fn now_epoch_secs() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}

src/api/runtime_zero.rs

@@ -0,0 +1,247 @@
+use std::sync::atomic::Ordering;
+
+use serde::Serialize;
+
+use crate::config::{MeFloorMode, ProxyConfig, UserMaxUniqueIpsMode};
+
+use super::ApiShared;
+
+#[derive(Serialize)]
+pub(super) struct SystemInfoData {
+    pub(super) version: String,
+    pub(super) target_arch: String,
+    pub(super) target_os: String,
+    pub(super) build_profile: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) git_commit: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) build_time_utc: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) rustc_version: Option<String>,
+    pub(super) process_started_at_epoch_secs: u64,
+    pub(super) uptime_seconds: f64,
+    pub(super) config_path: String,
+    pub(super) config_hash: String,
+    pub(super) config_reload_count: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) last_config_reload_epoch_secs: Option<u64>,
+}
+
+#[derive(Serialize)]
+pub(super) struct RuntimeGatesData {
+    pub(super) accepting_new_connections: bool,
+    pub(super) conditional_cast_enabled: bool,
+    pub(super) me_runtime_ready: bool,
+    pub(super) me2dc_fallback_enabled: bool,
+    pub(super) use_middle_proxy: bool,
+}
+
+#[derive(Serialize)]
+pub(super) struct EffectiveTimeoutLimits {
+    pub(super) client_handshake_secs: u64,
+    pub(super) tg_connect_secs: u64,
+    pub(super) client_keepalive_secs: u64,
+    pub(super) client_ack_secs: u64,
+    pub(super) me_one_retry: u8,
+    pub(super) me_one_timeout_ms: u64,
+}
+
+#[derive(Serialize)]
+pub(super) struct EffectiveUpstreamLimits {
+    pub(super) connect_retry_attempts: u32,
+    pub(super) connect_retry_backoff_ms: u64,
+    pub(super) connect_budget_ms: u64,
+    pub(super) unhealthy_fail_threshold: u32,
+    pub(super) connect_failfast_hard_errors: bool,
+}
+
+#[derive(Serialize)]
+pub(super) struct EffectiveMiddleProxyLimits {
+    pub(super) floor_mode: &'static str,
+    pub(super) adaptive_floor_idle_secs: u64,
+    pub(super) adaptive_floor_min_writers_single_endpoint: u8,
+    pub(super) adaptive_floor_min_writers_multi_endpoint: u8,
+    pub(super) adaptive_floor_recover_grace_secs: u64,
+    pub(super) adaptive_floor_writers_per_core_total: u16,
+    pub(super) adaptive_floor_cpu_cores_override: u16,
+    pub(super) adaptive_floor_max_extra_writers_single_per_core: u16,
+    pub(super) adaptive_floor_max_extra_writers_multi_per_core: u16,
+    pub(super) reconnect_max_concurrent_per_dc: u32,
+    pub(super) reconnect_backoff_base_ms: u64,
+    pub(super) reconnect_backoff_cap_ms: u64,
+    pub(super) reconnect_fast_retry_count: u32,
+    pub(super) me2dc_fallback: bool,
+}
+
+#[derive(Serialize)]
+pub(super) struct EffectiveUserIpPolicyLimits {
+    pub(super) mode: &'static str,
+    pub(super) window_secs: u64,
+}
+
+#[derive(Serialize)]
+pub(super) struct EffectiveLimitsData {
+    pub(super) update_every_secs: u64,
+    pub(super) me_reinit_every_secs: u64,
+    pub(super) me_pool_force_close_secs: u64,
+    pub(super) timeouts: EffectiveTimeoutLimits,
+    pub(super) upstream: EffectiveUpstreamLimits,
+    pub(super) middle_proxy: EffectiveMiddleProxyLimits,
+    pub(super) user_ip_policy: EffectiveUserIpPolicyLimits,
+}
+
+#[derive(Serialize)]
+pub(super) struct SecurityPostureData {
+    pub(super) api_read_only: bool,
+    pub(super) api_whitelist_enabled: bool,
+    pub(super) api_whitelist_entries: usize,
+    pub(super) api_auth_header_enabled: bool,
+    pub(super) proxy_protocol_enabled: bool,
+    pub(super) log_level: String,
+    pub(super) telemetry_core_enabled: bool,
+    pub(super) telemetry_user_enabled: bool,
+    pub(super) telemetry_me_level: String,
+}
+
+pub(super) fn build_system_info_data(
+    shared: &ApiShared,
+    _cfg: &ProxyConfig,
+    revision: &str,
+) -> SystemInfoData {
+    let last_reload_epoch_secs = shared
+        .runtime_state
+        .last_config_reload_epoch_secs
+        .load(Ordering::Relaxed);
+    let last_config_reload_epoch_secs = (last_reload_epoch_secs > 0).then_some(last_reload_epoch_secs);
+
+    let git_commit = option_env!("TELEMT_GIT_COMMIT")
+        .or(option_env!("VERGEN_GIT_SHA"))
+        .or(option_env!("GIT_COMMIT"))
+        .map(ToString::to_string);
+    let build_time_utc = option_env!("BUILD_TIME_UTC")
+        .or(option_env!("VERGEN_BUILD_TIMESTAMP"))
+        .map(ToString::to_string);
+    let rustc_version = option_env!("RUSTC_VERSION")
+        .or(option_env!("VERGEN_RUSTC_SEMVER"))
+        .map(ToString::to_string);
+
+    SystemInfoData {
+        version: env!("CARGO_PKG_VERSION").to_string(),
+        target_arch: std::env::consts::ARCH.to_string(),
+        target_os: std::env::consts::OS.to_string(),
+        build_profile: option_env!("PROFILE").unwrap_or("unknown").to_string(),
+        git_commit,
+        build_time_utc,
+        rustc_version,
+        process_started_at_epoch_secs: shared.runtime_state.process_started_at_epoch_secs,
+        uptime_seconds: shared.stats.uptime_secs(),
+        config_path: shared.config_path.display().to_string(),
+        config_hash: revision.to_string(),
+        config_reload_count: shared.runtime_state.config_reload_count.load(Ordering::Relaxed),
+        last_config_reload_epoch_secs,
+    }
+}
+
+pub(super) fn build_runtime_gates_data(shared: &ApiShared, cfg: &ProxyConfig) -> RuntimeGatesData {
+    let me_runtime_ready = if !cfg.general.use_middle_proxy {
+        true
+    } else {
+        shared
+            .me_pool
+            .as_ref()
+            .map(|pool| pool.is_runtime_ready())
+            .unwrap_or(false)
+    };
+
+    RuntimeGatesData {
+        accepting_new_connections: shared.runtime_state.admission_open.load(Ordering::Relaxed),
+        conditional_cast_enabled: cfg.general.use_middle_proxy,
+        me_runtime_ready,
+        me2dc_fallback_enabled: cfg.general.me2dc_fallback,
+        use_middle_proxy: cfg.general.use_middle_proxy,
+    }
+}
+
+pub(super) fn build_limits_effective_data(cfg: &ProxyConfig) -> EffectiveLimitsData {
+    EffectiveLimitsData {
+        update_every_secs: cfg.general.effective_update_every_secs(),
+        me_reinit_every_secs: cfg.general.effective_me_reinit_every_secs(),
+        me_pool_force_close_secs: cfg.general.effective_me_pool_force_close_secs(),
+        timeouts: EffectiveTimeoutLimits {
+            client_handshake_secs: cfg.timeouts.client_handshake,
+            tg_connect_secs: cfg.timeouts.tg_connect,
+            client_keepalive_secs: cfg.timeouts.client_keepalive,
+            client_ack_secs: cfg.timeouts.client_ack,
+            me_one_retry: cfg.timeouts.me_one_retry,
+            me_one_timeout_ms: cfg.timeouts.me_one_timeout_ms,
+        },
+        upstream: EffectiveUpstreamLimits {
+            connect_retry_attempts: cfg.general.upstream_connect_retry_attempts,
+            connect_retry_backoff_ms: cfg.general.upstream_connect_retry_backoff_ms,
+            connect_budget_ms: cfg.general.upstream_connect_budget_ms,
+            unhealthy_fail_threshold: cfg.general.upstream_unhealthy_fail_threshold,
+            connect_failfast_hard_errors: cfg.general.upstream_connect_failfast_hard_errors,
+        },
+        middle_proxy: EffectiveMiddleProxyLimits {
+            floor_mode: me_floor_mode_label(cfg.general.me_floor_mode),
+            adaptive_floor_idle_secs: cfg.general.me_adaptive_floor_idle_secs,
+            adaptive_floor_min_writers_single_endpoint: cfg
+                .general
+                .me_adaptive_floor_min_writers_single_endpoint,
+            adaptive_floor_min_writers_multi_endpoint: cfg
+                .general
+                .me_adaptive_floor_min_writers_multi_endpoint,
+            adaptive_floor_recover_grace_secs: cfg.general.me_adaptive_floor_recover_grace_secs,
+            adaptive_floor_writers_per_core_total: cfg
+                .general
+                .me_adaptive_floor_writers_per_core_total,
+            adaptive_floor_cpu_cores_override: cfg
+                .general
+                .me_adaptive_floor_cpu_cores_override,
+            adaptive_floor_max_extra_writers_single_per_core: cfg
+                .general
+                .me_adaptive_floor_max_extra_writers_single_per_core,
+            adaptive_floor_max_extra_writers_multi_per_core: cfg
+                .general
+                .me_adaptive_floor_max_extra_writers_multi_per_core,
+            reconnect_max_concurrent_per_dc: cfg.general.me_reconnect_max_concurrent_per_dc,
+            reconnect_backoff_base_ms: cfg.general.me_reconnect_backoff_base_ms,
+            reconnect_backoff_cap_ms: cfg.general.me_reconnect_backoff_cap_ms,
+            reconnect_fast_retry_count: cfg.general.me_reconnect_fast_retry_count,
+            me2dc_fallback: cfg.general.me2dc_fallback,
+        },
+        user_ip_policy: EffectiveUserIpPolicyLimits {
+            mode: user_max_unique_ips_mode_label(cfg.access.user_max_unique_ips_mode),
+            window_secs: cfg.access.user_max_unique_ips_window_secs,
+        },
+    }
+}
+
+pub(super) fn build_security_posture_data(cfg: &ProxyConfig) -> SecurityPostureData {
+    SecurityPostureData {
+        api_read_only: cfg.server.api.read_only,
+        api_whitelist_enabled: !cfg.server.api.whitelist.is_empty(),
+        api_whitelist_entries: cfg.server.api.whitelist.len(),
+        api_auth_header_enabled: !cfg.server.api.auth_header.is_empty(),
+        proxy_protocol_enabled: cfg.server.proxy_protocol,
+        log_level: cfg.general.log_level.to_string(),
+        telemetry_core_enabled: cfg.general.telemetry.core_enabled,
+        telemetry_user_enabled: cfg.general.telemetry.user_enabled,
+        telemetry_me_level: cfg.general.telemetry.me_level.to_string(),
+    }
+}
+
+fn user_max_unique_ips_mode_label(mode: UserMaxUniqueIpsMode) -> &'static str {
+    match mode {
+        UserMaxUniqueIpsMode::ActiveWindow => "active_window",
+        UserMaxUniqueIpsMode::TimeWindow => "time_window",
+        UserMaxUniqueIpsMode::Combined => "combined",
+    }
+}
+
+fn me_floor_mode_label(mode: MeFloorMode) -> &'static str {
+    match mode {
+        MeFloorMode::Static => "static",
+        MeFloorMode::Adaptive => "adaptive",
+    }
+}

src/api/users.rs

@@ -0,0 +1,499 @@
+use std::net::IpAddr;
+
+use hyper::StatusCode;
+
+use crate::config::ProxyConfig;
+use crate::ip_tracker::UserIpTracker;
+use crate::stats::Stats;
+
+use super::ApiShared;
+use super::config_store::{
+    ensure_expected_revision, load_config_from_disk, save_config_to_disk,
+};
+use super::model::{
+    ApiFailure, CreateUserRequest, CreateUserResponse, PatchUserRequest, RotateSecretRequest,
+    UserInfo, UserLinks, is_valid_ad_tag, is_valid_user_secret, is_valid_username,
+    parse_optional_expiration, random_user_secret,
+};
+
+pub(super) async fn create_user(
+    body: CreateUserRequest,
+    expected_revision: Option<String>,
+    shared: &ApiShared,
+) -> Result<(CreateUserResponse, String), ApiFailure> {
+    if !is_valid_username(&body.username) {
+        return Err(ApiFailure::bad_request(
+            "username must match [A-Za-z0-9_.-] and be 1..64 chars",
+        ));
+    }
+
+    let secret = match body.secret {
+        Some(secret) => {
+            if !is_valid_user_secret(&secret) {
+                return Err(ApiFailure::bad_request(
+                    "secret must be exactly 32 hex characters",
+                ));
+            }
+            secret
+        }
+        None => random_user_secret(),
+    };
+
+    if let Some(ad_tag) = body.user_ad_tag.as_ref() && !is_valid_ad_tag(ad_tag) {
+        return Err(ApiFailure::bad_request(
+            "user_ad_tag must be exactly 32 hex characters",
+        ));
+    }
+
+    let expiration = parse_optional_expiration(body.expiration_rfc3339.as_deref())?;
+    let _guard = shared.mutation_lock.lock().await;
+    let mut cfg = load_config_from_disk(&shared.config_path).await?;
+    ensure_expected_revision(&shared.config_path, expected_revision.as_deref()).await?;
+
+    if cfg.access.users.contains_key(&body.username) {
+        return Err(ApiFailure::new(
+            StatusCode::CONFLICT,
+            "user_exists",
+            "User already exists",
+        ));
+    }
+
+    cfg.access.users.insert(body.username.clone(), secret.clone());
+    if let Some(ad_tag) = body.user_ad_tag {
+        cfg.access.user_ad_tags.insert(body.username.clone(), ad_tag);
+    }
+    if let Some(limit) = body.max_tcp_conns {
+        cfg.access.user_max_tcp_conns.insert(body.username.clone(), limit);
+    }
+    if let Some(expiration) = expiration {
+        cfg.access
+            .user_expirations
+            .insert(body.username.clone(), expiration);
+    }
+    if let Some(quota) = body.data_quota_bytes {
+        cfg.access.user_data_quota.insert(body.username.clone(), quota);
+    }
+
+    let updated_limit = body.max_unique_ips;
+    if let Some(limit) = updated_limit {
+        cfg.access
+            .user_max_unique_ips
+            .insert(body.username.clone(), limit);
+    }
+
+    cfg.validate()
+        .map_err(|e| ApiFailure::bad_request(format!("config validation failed: {}", e)))?;
+
+    let revision = save_config_to_disk(&shared.config_path, &cfg).await?;
+    drop(_guard);
+
+    if let Some(limit) = updated_limit {
+        shared.ip_tracker.set_user_limit(&body.username, limit).await;
+    }
+
+    let users = users_from_config(
+        &cfg,
+        &shared.stats,
+        &shared.ip_tracker,
+        shared.startup_detected_ip_v4,
+        shared.startup_detected_ip_v6,
+    )
+    .await;
+    let user = users
+        .into_iter()
+        .find(|entry| entry.username == body.username)
+        .unwrap_or(UserInfo {
+            username: body.username.clone(),
+            user_ad_tag: None,
+            max_tcp_conns: None,
+            expiration_rfc3339: None,
+            data_quota_bytes: None,
+            max_unique_ips: updated_limit,
+            current_connections: 0,
+            active_unique_ips: 0,
+            active_unique_ips_list: Vec::new(),
+            recent_unique_ips: 0,
+            recent_unique_ips_list: Vec::new(),
+            total_octets: 0,
+            links: build_user_links(
+                &cfg,
+                &secret,
+                shared.startup_detected_ip_v4,
+                shared.startup_detected_ip_v6,
+            ),
+        });
+
+    Ok((CreateUserResponse { user, secret }, revision))
+}
+
+pub(super) async fn patch_user(
+    user: &str,
+    body: PatchUserRequest,
+    expected_revision: Option<String>,
+    shared: &ApiShared,
+) -> Result<(UserInfo, String), ApiFailure> {
+    if let Some(secret) = body.secret.as_ref() && !is_valid_user_secret(secret) {
+        return Err(ApiFailure::bad_request(
+            "secret must be exactly 32 hex characters",
+        ));
+    }
+    if let Some(ad_tag) = body.user_ad_tag.as_ref() && !is_valid_ad_tag(ad_tag) {
+        return Err(ApiFailure::bad_request(
+            "user_ad_tag must be exactly 32 hex characters",
+        ));
+    }
+    let expiration = parse_optional_expiration(body.expiration_rfc3339.as_deref())?;
+    let _guard = shared.mutation_lock.lock().await;
+    let mut cfg = load_config_from_disk(&shared.config_path).await?;
+    ensure_expected_revision(&shared.config_path, expected_revision.as_deref()).await?;
+
+    if !cfg.access.users.contains_key(user) {
+        return Err(ApiFailure::new(
+            StatusCode::NOT_FOUND,
+            "not_found",
+            "User not found",
+        ));
+    }
+
+    if let Some(secret) = body.secret {
+        cfg.access.users.insert(user.to_string(), secret);
+    }
+    if let Some(ad_tag) = body.user_ad_tag {
+        cfg.access.user_ad_tags.insert(user.to_string(), ad_tag);
+    }
+    if let Some(limit) = body.max_tcp_conns {
+        cfg.access.user_max_tcp_conns.insert(user.to_string(), limit);
+    }
+    if let Some(expiration) = expiration {
+        cfg.access.user_expirations.insert(user.to_string(), expiration);
+    }
+    if let Some(quota) = body.data_quota_bytes {
+        cfg.access.user_data_quota.insert(user.to_string(), quota);
+    }
+
+    let mut updated_limit = None;
+    if let Some(limit) = body.max_unique_ips {
+        cfg.access.user_max_unique_ips.insert(user.to_string(), limit);
+        updated_limit = Some(limit);
+    }
+
+    cfg.validate()
+        .map_err(|e| ApiFailure::bad_request(format!("config validation failed: {}", e)))?;
+
+    let revision = save_config_to_disk(&shared.config_path, &cfg).await?;
+    drop(_guard);
+    if let Some(limit) = updated_limit {
+        shared.ip_tracker.set_user_limit(user, limit).await;
+    }
+    let users = users_from_config(
+        &cfg,
+        &shared.stats,
+        &shared.ip_tracker,
+        shared.startup_detected_ip_v4,
+        shared.startup_detected_ip_v6,
+    )
+    .await;
+    let user_info = users
+        .into_iter()
+        .find(|entry| entry.username == user)
+        .ok_or_else(|| ApiFailure::internal("failed to build updated user view"))?;
+
+    Ok((user_info, revision))
+}
+
+pub(super) async fn rotate_secret(
+    user: &str,
+    body: RotateSecretRequest,
+    expected_revision: Option<String>,
+    shared: &ApiShared,
+) -> Result<(CreateUserResponse, String), ApiFailure> {
+    let secret = body.secret.unwrap_or_else(random_user_secret);
+    if !is_valid_user_secret(&secret) {
+        return Err(ApiFailure::bad_request(
+            "secret must be exactly 32 hex characters",
+        ));
+    }
+
+    let _guard = shared.mutation_lock.lock().await;
+    let mut cfg = load_config_from_disk(&shared.config_path).await?;
+    ensure_expected_revision(&shared.config_path, expected_revision.as_deref()).await?;
+
+    if !cfg.access.users.contains_key(user) {
+        return Err(ApiFailure::new(
+            StatusCode::NOT_FOUND,
+            "not_found",
+            "User not found",
+        ));
+    }
+
+    cfg.access.users.insert(user.to_string(), secret.clone());
+    cfg.validate()
+        .map_err(|e| ApiFailure::bad_request(format!("config validation failed: {}", e)))?;
+    let revision = save_config_to_disk(&shared.config_path, &cfg).await?;
+    drop(_guard);
+
+    let users = users_from_config(
+        &cfg,
+        &shared.stats,
+        &shared.ip_tracker,
+        shared.startup_detected_ip_v4,
+        shared.startup_detected_ip_v6,
+    )
+    .await;
+    let user_info = users
+        .into_iter()
+        .find(|entry| entry.username == user)
+        .ok_or_else(|| ApiFailure::internal("failed to build updated user view"))?;
+
+    Ok((
+        CreateUserResponse {
+            user: user_info,
+            secret,
+        },
+        revision,
+    ))
+}
+
+pub(super) async fn delete_user(
+    user: &str,
+    expected_revision: Option<String>,
+    shared: &ApiShared,
+) -> Result<(String, String), ApiFailure> {
+    let _guard = shared.mutation_lock.lock().await;
+    let mut cfg = load_config_from_disk(&shared.config_path).await?;
+    ensure_expected_revision(&shared.config_path, expected_revision.as_deref()).await?;
+
+    if !cfg.access.users.contains_key(user) {
+        return Err(ApiFailure::new(
+            StatusCode::NOT_FOUND,
+            "not_found",
+            "User not found",
+        ));
+    }
+    if cfg.access.users.len() <= 1 {
+        return Err(ApiFailure::new(
+            StatusCode::CONFLICT,
+            "last_user_forbidden",
+            "Cannot delete the last configured user",
+        ));
+    }
+
+    cfg.access.users.remove(user);
+    cfg.access.user_ad_tags.remove(user);
+    cfg.access.user_max_tcp_conns.remove(user);
+    cfg.access.user_expirations.remove(user);
+    cfg.access.user_data_quota.remove(user);
+    cfg.access.user_max_unique_ips.remove(user);
+
+    cfg.validate()
+        .map_err(|e| ApiFailure::bad_request(format!("config validation failed: {}", e)))?;
+    let revision = save_config_to_disk(&shared.config_path, &cfg).await?;
+    drop(_guard);
+    shared.ip_tracker.remove_user_limit(user).await;
+    shared.ip_tracker.clear_user_ips(user).await;
+
+    Ok((user.to_string(), revision))
+}
+
+pub(super) async fn users_from_config(
+    cfg: &ProxyConfig,
+    stats: &Stats,
+    ip_tracker: &UserIpTracker,
+    startup_detected_ip_v4: Option<IpAddr>,
+    startup_detected_ip_v6: Option<IpAddr>,
+) -> Vec<UserInfo> {
+    let mut names = cfg.access.users.keys().cloned().collect::<Vec<_>>();
+    names.sort();
+    let active_ip_lists = ip_tracker.get_active_ips_for_users(&names).await;
+    let recent_ip_lists = ip_tracker.get_recent_ips_for_users(&names).await;
+
+    let mut users = Vec::with_capacity(names.len());
+    for username in names {
+        let active_ip_list = active_ip_lists
+            .get(&username)
+            .cloned()
+            .unwrap_or_else(Vec::new);
+        let recent_ip_list = recent_ip_lists
+            .get(&username)
+            .cloned()
+            .unwrap_or_else(Vec::new);
+        let links = cfg
+            .access
+            .users
+            .get(&username)
+            .map(|secret| {
+                build_user_links(
+                    cfg,
+                    secret,
+                    startup_detected_ip_v4,
+                    startup_detected_ip_v6,
+                )
+            })
+            .unwrap_or(UserLinks {
+                classic: Vec::new(),
+                secure: Vec::new(),
+                tls: Vec::new(),
+            });
+        users.push(UserInfo {
+            user_ad_tag: cfg.access.user_ad_tags.get(&username).cloned(),
+            max_tcp_conns: cfg.access.user_max_tcp_conns.get(&username).copied(),
+            expiration_rfc3339: cfg
+                .access
+                .user_expirations
+                .get(&username)
+                .map(chrono::DateTime::<chrono::Utc>::to_rfc3339),
+            data_quota_bytes: cfg.access.user_data_quota.get(&username).copied(),
+            max_unique_ips: cfg.access.user_max_unique_ips.get(&username).copied(),
+            current_connections: stats.get_user_curr_connects(&username),
+            active_unique_ips: active_ip_list.len(),
+            active_unique_ips_list: active_ip_list,
+            recent_unique_ips: recent_ip_list.len(),
+            recent_unique_ips_list: recent_ip_list,
+            total_octets: stats.get_user_total_octets(&username),
+            links,
+            username,
+        });
+    }
+    users
+}
+
+fn build_user_links(
+    cfg: &ProxyConfig,
+    secret: &str,
+    startup_detected_ip_v4: Option<IpAddr>,
+    startup_detected_ip_v6: Option<IpAddr>,
+) -> UserLinks {
+    let hosts = resolve_link_hosts(cfg, startup_detected_ip_v4, startup_detected_ip_v6);
+    let port = cfg.general.links.public_port.unwrap_or(cfg.server.port);
+    let tls_domains = resolve_tls_domains(cfg);
+
+    let mut classic = Vec::new();
+    let mut secure = Vec::new();
+    let mut tls = Vec::new();
+
+    for host in &hosts {
+        if cfg.general.modes.classic {
+            classic.push(format!(
+                "tg://proxy?server={}&port={}&secret={}",
+                host, port, secret
+            ));
+        }
+        if cfg.general.modes.secure {
+            secure.push(format!(
+                "tg://proxy?server={}&port={}&secret=dd{}",
+                host, port, secret
+            ));
+        }
+        if cfg.general.modes.tls {
+            for domain in &tls_domains {
+                let domain_hex = hex::encode(domain);
+                tls.push(format!(
+                    "tg://proxy?server={}&port={}&secret=ee{}{}",
+                    host, port, secret, domain_hex
+                ));
+            }
+        }
+    }
+
+    UserLinks {
+        classic,
+        secure,
+        tls,
+    }
+}
+
+fn resolve_link_hosts(
+    cfg: &ProxyConfig,
+    startup_detected_ip_v4: Option<IpAddr>,
+    startup_detected_ip_v6: Option<IpAddr>,
+) -> Vec<String> {
+    if let Some(host) = cfg
+        .general
+        .links
+        .public_host
+        .as_deref()
+        .map(str::trim)
+        .filter(|value| !value.is_empty())
+    {
+        return vec![host.to_string()];
+    }
+
+    let mut startup_hosts = Vec::new();
+    if let Some(ip) = startup_detected_ip_v4 {
+        push_unique_host(&mut startup_hosts, &ip.to_string());
+    }
+    if let Some(ip) = startup_detected_ip_v6 {
+        push_unique_host(&mut startup_hosts, &ip.to_string());
+    }
+    if !startup_hosts.is_empty() {
+        return startup_hosts;
+    }
+
+    let mut hosts = Vec::new();
+    for listener in &cfg.server.listeners {
+        if let Some(host) = listener
+            .announce
+            .as_deref()
+            .map(str::trim)
+            .filter(|value| !value.is_empty())
+        {
+            push_unique_host(&mut hosts, host);
+            continue;
+        }
+        if let Some(ip) = listener.announce_ip {
+            if !ip.is_unspecified() {
+                push_unique_host(&mut hosts, &ip.to_string());
+            }
+            continue;
+        }
+        if !listener.ip.is_unspecified() {
+            push_unique_host(&mut hosts, &listener.ip.to_string());
+        }
+    }
+
+    if hosts.is_empty() {
+        if let Some(host) = cfg.server.listen_addr_ipv4.as_deref() {
+            push_host_from_legacy_listen(&mut hosts, host);
+        }
+        if let Some(host) = cfg.server.listen_addr_ipv6.as_deref() {
+            push_host_from_legacy_listen(&mut hosts, host);
+        }
+    }
+
+    hosts
+}
+
+fn push_host_from_legacy_listen(hosts: &mut Vec<String>, raw: &str) {
+    let candidate = raw.trim();
+    if candidate.is_empty() {
+        return;
+    }
+
+    match candidate.parse::<IpAddr>() {
+        Ok(ip) if ip.is_unspecified() => {}
+        Ok(ip) => push_unique_host(hosts, &ip.to_string()),
+        Err(_) => push_unique_host(hosts, candidate),
+    }
+}
+
+fn push_unique_host(hosts: &mut Vec<String>, candidate: &str) {
+    if !hosts.iter().any(|existing| existing == candidate) {
+        hosts.push(candidate.to_string());
+    }
+}
+
+fn resolve_tls_domains(cfg: &ProxyConfig) -> Vec<&str> {
+    let mut domains = Vec::with_capacity(1 + cfg.censorship.tls_domains.len());
+    let primary = cfg.censorship.tls_domain.as_str();
+    if !primary.is_empty() {
+        domains.push(primary);
+    }
+    for domain in &cfg.censorship.tls_domains {
+        let value = domain.as_str();
+        if value.is_empty() || domains.contains(&value) {
+            continue;
+        }
+        domains.push(value);
+    }
+    domains
+}

src/cli.rs

@@ -194,6 +194,12 @@ prefer_ipv6 = false
 fast_mode = true
 use_middle_proxy = false
 log_level = "normal"
+desync_all_full = false
+update_every = 43200
+hardswap = false
+me_pool_drain_ttl_secs = 90
+me_pool_min_fresh_ratio = 0.8
+me_reinit_drain_timeout_secs = 120
 
 [network]
 ipv4 = true
@@ -213,6 +219,7 @@ listen_addr_ipv6 = "::"
 
 [[server.listeners]]
 ip = "0.0.0.0"
+# reuse_allow = false # Set true only when intentionally running multiple telemt instances on same port
 
 [[server.listeners]]
 ip = "::"
@@ -228,6 +235,7 @@ tls_domain = "{domain}"
 mask = true
 mask_port = 443
 fake_cert_len = 2048
+tls_full_cert_ttl_secs = 90
 
 [access]
 replay_check_len = 65536

src/config/defaults.rs

@@ -1,9 +1,30 @@
-use std::net::IpAddr;
 use std::collections::HashMap;
 use ipnetwork::IpNetwork;
 use serde::Deserialize;
 
 // Helper defaults kept private to the config module.
+const DEFAULT_NETWORK_IPV6: Option<bool> = Some(false);
+const DEFAULT_STUN_TCP_FALLBACK: bool = true;
+const DEFAULT_MIDDLE_PROXY_WARM_STANDBY: usize = 16;
+const DEFAULT_ME_RECONNECT_MAX_CONCURRENT_PER_DC: u32 = 8;
+const DEFAULT_ME_RECONNECT_FAST_RETRY_COUNT: u32 = 16;
+const DEFAULT_ME_SINGLE_ENDPOINT_SHADOW_WRITERS: u8 = 2;
+const DEFAULT_ME_ADAPTIVE_FLOOR_IDLE_SECS: u64 = 90;
+const DEFAULT_ME_ADAPTIVE_FLOOR_MIN_WRITERS_SINGLE_ENDPOINT: u8 = 1;
+const DEFAULT_ME_ADAPTIVE_FLOOR_MIN_WRITERS_MULTI_ENDPOINT: u8 = 1;
+const DEFAULT_ME_ADAPTIVE_FLOOR_RECOVER_GRACE_SECS: u64 = 180;
+const DEFAULT_ME_ADAPTIVE_FLOOR_WRITERS_PER_CORE_TOTAL: u16 = 48;
+const DEFAULT_ME_ADAPTIVE_FLOOR_CPU_CORES_OVERRIDE: u16 = 0;
+const DEFAULT_ME_ADAPTIVE_FLOOR_MAX_EXTRA_WRITERS_SINGLE_PER_CORE: u16 = 1;
+const DEFAULT_ME_ADAPTIVE_FLOOR_MAX_EXTRA_WRITERS_MULTI_PER_CORE: u16 = 2;
+const DEFAULT_USER_MAX_UNIQUE_IPS_WINDOW_SECS: u64 = 30;
+const DEFAULT_UPSTREAM_CONNECT_RETRY_ATTEMPTS: u32 = 2;
+const DEFAULT_UPSTREAM_UNHEALTHY_FAIL_THRESHOLD: u32 = 5;
+const DEFAULT_UPSTREAM_CONNECT_BUDGET_MS: u64 = 3000;
+const DEFAULT_LISTEN_ADDR_IPV6: &str = "::";
+const DEFAULT_ACCESS_USER: &str = "default";
+const DEFAULT_ACCESS_SECRET: &str = "00000000000000000000000000000000";
+
 pub(crate) fn default_true() -> bool {
     true
 }
@@ -13,7 +34,7 @@ pub(crate) fn default_port() -> u16 {
 }
 
 pub(crate) fn default_tls_domain() -> String {
-    "www.google.com".to_string()
+    "petrovich.ru".to_string()
 }
 
 pub(crate) fn default_mask_port() -> u16 {
@@ -37,7 +58,7 @@ pub(crate) fn default_replay_window_secs() -> u64 {
 }
 
 pub(crate) fn default_handshake_timeout() -> u64 {
-    15
+    30
 }
 
 pub(crate) fn default_connect_timeout() -> u64 {
@@ -52,17 +73,21 @@ pub(crate) fn default_ack_timeout() -> u64 {
     300
 }
 pub(crate) fn default_me_one_retry() -> u8 {
-    3
+    12
 }
 
 pub(crate) fn default_me_one_timeout() -> u64 {
-    1500
+    1200
 }
 
 pub(crate) fn default_listen_addr() -> String {
     "0.0.0.0".to_string()
 }
 
+pub(crate) fn default_listen_addr_ipv4() -> Option<String> {
+    Some(default_listen_addr())
+}
+
 pub(crate) fn default_weight() -> u16 {
     1
 }
@@ -74,24 +99,101 @@ pub(crate) fn default_metrics_whitelist() -> Vec<IpNetwork> {
     ]
 }
 
+pub(crate) fn default_api_listen() -> String {
+    "127.0.0.1:9091".to_string()
+}
+
+pub(crate) fn default_api_whitelist() -> Vec<IpNetwork> {
+    default_metrics_whitelist()
+}
+
+pub(crate) fn default_api_request_body_limit_bytes() -> usize {
+    64 * 1024
+}
+
+pub(crate) fn default_api_minimal_runtime_enabled() -> bool {
+    false
+}
+
+pub(crate) fn default_api_minimal_runtime_cache_ttl_ms() -> u64 {
+    1000
+}
+
+pub(crate) fn default_api_runtime_edge_enabled() -> bool { false }
+pub(crate) fn default_api_runtime_edge_cache_ttl_ms() -> u64 { 1000 }
+pub(crate) fn default_api_runtime_edge_top_n() -> usize { 10 }
+pub(crate) fn default_api_runtime_edge_events_capacity() -> usize { 256 }
+
+pub(crate) fn default_proxy_protocol_header_timeout_ms() -> u64 {
+    500
+}
+
 pub(crate) fn default_prefer_4() -> u8 {
     4
 }
 
+pub(crate) fn default_network_ipv6() -> Option<bool> {
+    DEFAULT_NETWORK_IPV6
+}
+
+pub(crate) fn default_stun_tcp_fallback() -> bool {
+    DEFAULT_STUN_TCP_FALLBACK
+}
+
 pub(crate) fn default_unknown_dc_log_path() -> Option<String> {
     Some("unknown-dc.txt".to_string())
 }
 
+pub(crate) fn default_unknown_dc_file_log_enabled() -> bool {
+    false
+}
+
 pub(crate) fn default_pool_size() -> usize {
-    2
+    8
+}
+
+pub(crate) fn default_proxy_secret_path() -> Option<String> {
+    Some("proxy-secret".to_string())
+}
+
+pub(crate) fn default_proxy_config_v4_cache_path() -> Option<String> {
+    Some("cache/proxy-config-v4.txt".to_string())
+}
+
+pub(crate) fn default_proxy_config_v6_cache_path() -> Option<String> {
+    Some("cache/proxy-config-v6.txt".to_string())
+}
+
+pub(crate) fn default_middle_proxy_nat_stun() -> Option<String> {
+    None
+}
+
+pub(crate) fn default_middle_proxy_nat_stun_servers() -> Vec<String> {
+    Vec::new()
+}
+
+pub(crate) fn default_stun_nat_probe_concurrency() -> usize {
+    8
+}
+
+pub(crate) fn default_middle_proxy_warm_standby() -> usize {
+    DEFAULT_MIDDLE_PROXY_WARM_STANDBY
+}
+
+pub(crate) fn default_me_init_retry_attempts() -> u32 {
+    0
+}
+
+pub(crate) fn default_me2dc_fallback() -> bool {
+    true
 }
 
 pub(crate) fn default_keepalive_interval() -> u64 {
-    25
+    8
 }
 
 pub(crate) fn default_keepalive_jitter() -> u64 {
-    5
+    2
 }
 
 pub(crate) fn default_warmup_step_delay_ms() -> u64 {
@@ -110,6 +212,334 @@ pub(crate) fn default_reconnect_backoff_cap_ms() -> u64 {
     30_000
 }
 
+pub(crate) fn default_me_reconnect_max_concurrent_per_dc() -> u32 {
+    DEFAULT_ME_RECONNECT_MAX_CONCURRENT_PER_DC
+}
+
+pub(crate) fn default_me_reconnect_fast_retry_count() -> u32 {
+    DEFAULT_ME_RECONNECT_FAST_RETRY_COUNT
+}
+
+pub(crate) fn default_me_single_endpoint_shadow_writers() -> u8 {
+    DEFAULT_ME_SINGLE_ENDPOINT_SHADOW_WRITERS
+}
+
+pub(crate) fn default_me_single_endpoint_outage_mode_enabled() -> bool {
+    true
+}
+
+pub(crate) fn default_me_single_endpoint_outage_disable_quarantine() -> bool {
+    true
+}
+
+pub(crate) fn default_me_single_endpoint_outage_backoff_min_ms() -> u64 {
+    250
+}
+
+pub(crate) fn default_me_single_endpoint_outage_backoff_max_ms() -> u64 {
+    3000
+}
+
+pub(crate) fn default_me_single_endpoint_shadow_rotate_every_secs() -> u64 {
+    900
+}
+
+pub(crate) fn default_me_adaptive_floor_idle_secs() -> u64 {
+    DEFAULT_ME_ADAPTIVE_FLOOR_IDLE_SECS
+}
+
+pub(crate) fn default_me_adaptive_floor_min_writers_single_endpoint() -> u8 {
+    DEFAULT_ME_ADAPTIVE_FLOOR_MIN_WRITERS_SINGLE_ENDPOINT
+}
+
+pub(crate) fn default_me_adaptive_floor_min_writers_multi_endpoint() -> u8 {
+    DEFAULT_ME_ADAPTIVE_FLOOR_MIN_WRITERS_MULTI_ENDPOINT
+}
+
+pub(crate) fn default_me_adaptive_floor_recover_grace_secs() -> u64 {
+    DEFAULT_ME_ADAPTIVE_FLOOR_RECOVER_GRACE_SECS
+}
+
+pub(crate) fn default_me_adaptive_floor_writers_per_core_total() -> u16 {
+    DEFAULT_ME_ADAPTIVE_FLOOR_WRITERS_PER_CORE_TOTAL
+}
+
+pub(crate) fn default_me_adaptive_floor_cpu_cores_override() -> u16 {
+    DEFAULT_ME_ADAPTIVE_FLOOR_CPU_CORES_OVERRIDE
+}
+
+pub(crate) fn default_me_adaptive_floor_max_extra_writers_single_per_core() -> u16 {
+    DEFAULT_ME_ADAPTIVE_FLOOR_MAX_EXTRA_WRITERS_SINGLE_PER_CORE
+}
+
+pub(crate) fn default_me_adaptive_floor_max_extra_writers_multi_per_core() -> u16 {
+    DEFAULT_ME_ADAPTIVE_FLOOR_MAX_EXTRA_WRITERS_MULTI_PER_CORE
+}
+
+pub(crate) fn default_upstream_connect_retry_attempts() -> u32 {
+    DEFAULT_UPSTREAM_CONNECT_RETRY_ATTEMPTS
+}
+
+pub(crate) fn default_upstream_connect_retry_backoff_ms() -> u64 {
+    100
+}
+
+pub(crate) fn default_upstream_unhealthy_fail_threshold() -> u32 {
+    DEFAULT_UPSTREAM_UNHEALTHY_FAIL_THRESHOLD
+}
+
+pub(crate) fn default_upstream_connect_budget_ms() -> u64 {
+    DEFAULT_UPSTREAM_CONNECT_BUDGET_MS
+}
+
+pub(crate) fn default_upstream_connect_failfast_hard_errors() -> bool {
+    false
+}
+
+pub(crate) fn default_rpc_proxy_req_every() -> u64 {
+    0
+}
+
+pub(crate) fn default_crypto_pending_buffer() -> usize {
+    256 * 1024
+}
+
+pub(crate) fn default_max_client_frame() -> usize {
+    16 * 1024 * 1024
+}
+
+pub(crate) fn default_desync_all_full() -> bool {
+    false
+}
+
+pub(crate) fn default_me_route_backpressure_base_timeout_ms() -> u64 {
+    25
+}
+
+pub(crate) fn default_me_route_backpressure_high_timeout_ms() -> u64 {
+    120
+}
+
+pub(crate) fn default_me_route_backpressure_high_watermark_pct() -> u8 {
+    80
+}
+
+pub(crate) fn default_me_route_no_writer_wait_ms() -> u64 {
+    250
+}
+
+pub(crate) fn default_me_route_inline_recovery_attempts() -> u32 {
+    3
+}
+
+pub(crate) fn default_me_route_inline_recovery_wait_ms() -> u64 {
+    3000
+}
+
+pub(crate) fn default_beobachten_minutes() -> u64 {
+    10
+}
+
+pub(crate) fn default_beobachten_flush_secs() -> u64 {
+    15
+}
+
+pub(crate) fn default_beobachten_file() -> String {
+    "cache/beobachten.txt".to_string()
+}
+
+pub(crate) fn default_tls_new_session_tickets() -> u8 {
+    0
+}
+
+pub(crate) fn default_tls_full_cert_ttl_secs() -> u64 {
+    90
+}
+
+pub(crate) fn default_server_hello_delay_min_ms() -> u64 {
+    0
+}
+
+pub(crate) fn default_server_hello_delay_max_ms() -> u64 {
+    0
+}
+
+pub(crate) fn default_alpn_enforce() -> bool {
+    true
+}
+
+pub(crate) fn default_stun_servers() -> Vec<String> {
+    vec![
+        "stun.l.google.com:5349".to_string(),
+        "stun1.l.google.com:3478".to_string(),
+        "stun.gmx.net:3478".to_string(),
+        "stun.l.google.com:19302".to_string(),
+        "stun.1und1.de:3478".to_string(),
+        "stun1.l.google.com:19302".to_string(),
+        "stun2.l.google.com:19302".to_string(),
+        "stun3.l.google.com:19302".to_string(),
+        "stun4.l.google.com:19302".to_string(),
+        "stun.services.mozilla.com:3478".to_string(),
+        "stun.stunprotocol.org:3478".to_string(),
+        "stun.nextcloud.com:3478".to_string(),
+        "stun.voip.eutelia.it:3478".to_string(),
+    ]
+}
+
+pub(crate) fn default_http_ip_detect_urls() -> Vec<String> {
+    vec![
+        "https://ifconfig.me/ip".to_string(),
+        "https://api.ipify.org".to_string(),
+    ]
+}
+
+pub(crate) fn default_cache_public_ip_path() -> String {
+    "cache/public_ip.txt".to_string()
+}
+
+pub(crate) fn default_proxy_secret_reload_secs() -> u64 {
+    60 * 60
+}
+
+pub(crate) fn default_proxy_config_reload_secs() -> u64 {
+    60 * 60
+}
+
+pub(crate) fn default_update_every_secs() -> u64 {
+    5 * 60
+}
+
+pub(crate) fn default_update_every() -> Option<u64> {
+    Some(default_update_every_secs())
+}
+
+pub(crate) fn default_me_reinit_every_secs() -> u64 {
+    15 * 60
+}
+
+pub(crate) fn default_me_reinit_singleflight() -> bool {
+    true
+}
+
+pub(crate) fn default_me_reinit_trigger_channel() -> usize {
+    64
+}
+
+pub(crate) fn default_me_reinit_coalesce_window_ms() -> u64 {
+    200
+}
+
+pub(crate) fn default_me_hardswap_warmup_delay_min_ms() -> u64 {
+    1000
+}
+
+pub(crate) fn default_me_hardswap_warmup_delay_max_ms() -> u64 {
+    2000
+}
+
+pub(crate) fn default_me_hardswap_warmup_extra_passes() -> u8 {
+    3
+}
+
+pub(crate) fn default_me_hardswap_warmup_pass_backoff_base_ms() -> u64 {
+    500
+}
+
+pub(crate) fn default_me_config_stable_snapshots() -> u8 {
+    2
+}
+
+pub(crate) fn default_me_config_apply_cooldown_secs() -> u64 {
+    300
+}
+
+pub(crate) fn default_me_snapshot_require_http_2xx() -> bool {
+    true
+}
+
+pub(crate) fn default_me_snapshot_reject_empty_map() -> bool {
+    true
+}
+
+pub(crate) fn default_me_snapshot_min_proxy_for_lines() -> u32 {
+    1
+}
+
+pub(crate) fn default_proxy_secret_stable_snapshots() -> u8 {
+    2
+}
+
+pub(crate) fn default_proxy_secret_rotate_runtime() -> bool {
+    true
+}
+
+pub(crate) fn default_me_secret_atomic_snapshot() -> bool {
+    true
+}
+
+pub(crate) fn default_proxy_secret_len_max() -> usize {
+    256
+}
+
+pub(crate) fn default_me_reinit_drain_timeout_secs() -> u64 {
+    120
+}
+
+pub(crate) fn default_me_pool_drain_ttl_secs() -> u64 {
+    90
+}
+
+pub(crate) fn default_me_bind_stale_ttl_secs() -> u64 {
+    default_me_pool_drain_ttl_secs()
+}
+
+pub(crate) fn default_me_pool_min_fresh_ratio() -> f32 {
+    0.8
+}
+
+pub(crate) fn default_me_deterministic_writer_sort() -> bool {
+    true
+}
+
+pub(crate) fn default_hardswap() -> bool {
+    true
+}
+
+pub(crate) fn default_ntp_check() -> bool {
+    true
+}
+
+pub(crate) fn default_ntp_servers() -> Vec<String> {
+    vec!["pool.ntp.org".to_string()]
+}
+
+pub(crate) fn default_fast_mode_min_tls_record() -> usize {
+    0
+}
+
+pub(crate) fn default_degradation_min_unavailable_dc_groups() -> u8 {
+    2
+}
+
+pub(crate) fn default_listen_addr_ipv6() -> String {
+    DEFAULT_LISTEN_ADDR_IPV6.to_string()
+}
+
+pub(crate) fn default_listen_addr_ipv6_opt() -> Option<String> {
+    Some(default_listen_addr_ipv6())
+}
+
+pub(crate) fn default_access_users() -> HashMap<String, String> {
+    HashMap::from([(
+        DEFAULT_ACCESS_USER.to_string(),
+        DEFAULT_ACCESS_SECRET.to_string(),
+    )])
+}
+
+pub(crate) fn default_user_max_unique_ips_window_secs() -> u64 {
+    DEFAULT_USER_MAX_UNIQUE_IPS_WINDOW_SECS
+}
+
 // Custom deserializer helpers
 
 #[derive(Deserialize)]

src/crypto/aes.rs

@@ -11,6 +11,8 @@
 //!   `HandshakeSuccess`, `ObfuscationParams`) are responsible for
 //!   zeroizing their own copies.
 
+#![allow(dead_code)]
+
 use aes::Aes256;
 use ctr::{Ctr128BE, cipher::{KeyIvInit, StreamCipher}};
 use zeroize::Zeroize;
@@ -21,13 +23,13 @@ type Aes256Ctr = Ctr128BE<Aes256>;
 // ============= AES-256-CTR =============
 
 /// AES-256-CTR encryptor/decryptor
-/// 
+///
 /// CTR mode is symmetric — encryption and decryption are the same operation.
 ///
 /// **Zeroize note:** The inner `Aes256Ctr` cipher state (expanded key schedule
-/// + counter) is opaque and cannot be zeroized. If you need to protect key
-/// material, zeroize the `[u8; 32]` key and `u128` IV at the call site
-/// before dropping them.
+///     + counter) is opaque and cannot be zeroized. If you need to protect key
+///     material, zeroize the `[u8; 32]` key and `u128` IV at the call site
+///     before dropping them.
 pub struct AesCtr {
     cipher: Aes256Ctr,
 }
@@ -147,7 +149,7 @@ impl AesCbc {
     ///
     /// CBC Encryption: C[i] = AES_Encrypt(P[i] XOR C[i-1]), where C[-1] = IV
     pub fn encrypt(&self, data: &[u8]) -> Result<Vec<u8>> {
-        if data.len() % Self::BLOCK_SIZE != 0 {
+        if !data.len().is_multiple_of(Self::BLOCK_SIZE) {
             return Err(ProxyError::Crypto(
                 format!("CBC data must be aligned to 16 bytes, got {}", data.len())
             ));
@@ -178,7 +180,7 @@ impl AesCbc {
     ///
     /// CBC Decryption: P[i] = AES_Decrypt(C[i]) XOR C[i-1], where C[-1] = IV
     pub fn decrypt(&self, data: &[u8]) -> Result<Vec<u8>> {
-        if data.len() % Self::BLOCK_SIZE != 0 {
+        if !data.len().is_multiple_of(Self::BLOCK_SIZE) {
             return Err(ProxyError::Crypto(
                 format!("CBC data must be aligned to 16 bytes, got {}", data.len())
             ));
@@ -207,7 +209,7 @@ impl AesCbc {
     
     /// Encrypt data in-place
     pub fn encrypt_in_place(&self, data: &mut [u8]) -> Result<()> {
-        if data.len() % Self::BLOCK_SIZE != 0 {
+        if !data.len().is_multiple_of(Self::BLOCK_SIZE) {
             return Err(ProxyError::Crypto(
                 format!("CBC data must be aligned to 16 bytes, got {}", data.len())
             ));
@@ -240,7 +242,7 @@ impl AesCbc {
     
     /// Decrypt data in-place
     pub fn decrypt_in_place(&self, data: &mut [u8]) -> Result<()> {
-        if data.len() % Self::BLOCK_SIZE != 0 {
+        if !data.len().is_multiple_of(Self::BLOCK_SIZE) {
             return Err(ProxyError::Crypto(
                 format!("CBC data must be aligned to 16 bytes, got {}", data.len())
             ));

src/crypto/hash.rs

@@ -55,10 +55,16 @@ pub fn crc32(data: &[u8]) -> u32 {
     crc32fast::hash(data)
 }
 
+/// CRC32C (Castagnoli)
+pub fn crc32c(data: &[u8]) -> u32 {
+    crc32c::crc32c(data)
+}
+
 /// Build the exact prekey buffer used by Telegram Middle Proxy KDF.
 ///
 /// Returned buffer layout (IPv4):
 /// nonce_srv | nonce_clt | clt_ts | srv_ip | clt_port | purpose | clt_ip | srv_port | secret | nonce_srv | [clt_v6 | srv_v6] | nonce_clt
+#[allow(clippy::too_many_arguments)]
 pub fn build_middleproxy_prekey(
     nonce_srv: &[u8; 16],
     nonce_clt: &[u8; 16],
@@ -103,6 +109,7 @@ pub fn build_middleproxy_prekey(
 /// Uses MD5 + SHA-1 as mandated by the Telegram Middle Proxy protocol.
 /// These algorithms are NOT replaceable here — changing them would break
 /// interoperability with Telegram's middle proxy infrastructure.
+#[allow(clippy::too_many_arguments)]
 pub fn derive_middleproxy_keys(
     nonce_srv: &[u8; 16],
     nonce_clt: &[u8; 16],

src/crypto/mod.rs

@@ -5,5 +5,7 @@ pub mod hash;
 pub mod random;
 
 pub use aes::{AesCtr, AesCbc};
-pub use hash::{sha256, sha256_hmac, sha1, md5, crc32, derive_middleproxy_keys, build_middleproxy_prekey};
+pub use hash::{
+    build_middleproxy_prekey, crc32, crc32c, derive_middleproxy_keys, sha256, sha256_hmac,
+};
 pub use random::SecureRandom;

src/crypto/random.rs

@@ -1,5 +1,8 @@
 //! Pseudorandom
 
+#![allow(deprecated)]
+#![allow(dead_code)]
+
 use rand::{Rng, RngCore, SeedableRng};
 use rand::rngs::StdRng;
 use parking_lot::Mutex;
@@ -18,6 +21,7 @@ struct SecureRandomInner {
     rng: StdRng,
     cipher: AesCtr,
     buffer: Vec<u8>,
+    buffer_start: usize,
 }
 
 impl Drop for SecureRandomInner {
@@ -45,23 +49,50 @@ impl SecureRandom {
                 rng,
                 cipher,
                 buffer: Vec::with_capacity(1024),
+                buffer_start: 0,
             }),
         }
     }
     
-    /// Generate random bytes
-    pub fn bytes(&self, len: usize) -> Vec<u8> {
+    /// Fill a caller-provided buffer with random bytes.
+    pub fn fill(&self, out: &mut [u8]) {
         let mut inner = self.inner.lock();
         const CHUNK_SIZE: usize = 512;
-        
-        while inner.buffer.len() < len {
-            let mut chunk = vec![0u8; CHUNK_SIZE];
-            inner.rng.fill_bytes(&mut chunk);
-            inner.cipher.apply(&mut chunk);
-            inner.buffer.extend_from_slice(&chunk);
+
+        let mut written = 0usize;
+        while written < out.len() {
+            if inner.buffer_start >= inner.buffer.len() {
+                inner.buffer.clear();
+                inner.buffer_start = 0;
+            }
+
+            if inner.buffer.is_empty() {
+                let mut chunk = vec![0u8; CHUNK_SIZE];
+                inner.rng.fill_bytes(&mut chunk);
+                inner.cipher.apply(&mut chunk);
+                inner.buffer.extend_from_slice(&chunk);
+                inner.buffer_start = 0;
+            }
+
+            let available = inner.buffer.len().saturating_sub(inner.buffer_start);
+            let take = (out.len() - written).min(available);
+            let start = inner.buffer_start;
+            let end = start + take;
+            out[written..written + take].copy_from_slice(&inner.buffer[start..end]);
+            inner.buffer_start = end;
+            if inner.buffer_start >= inner.buffer.len() {
+                inner.buffer.clear();
+                inner.buffer_start = 0;
+            }
+            written += take;
         }
-        
-        inner.buffer.drain(..len).collect()
+    }
+
+    /// Generate random bytes
+    pub fn bytes(&self, len: usize) -> Vec<u8> {
+        let mut out = vec![0u8; len];
+        self.fill(&mut out);
+        out
     }
     
     /// Generate random number in range [0, max)
@@ -79,7 +110,7 @@ impl SecureRandom {
             return 0;
         }
         
-        let bytes_needed = (k + 7) / 8;
+        let bytes_needed = k.div_ceil(8);
         let bytes = self.bytes(bytes_needed.min(8));
         
         let mut result = 0u64;

src/error.rs

@@ -1,5 +1,7 @@
 //! Error Types
 
+#![allow(dead_code)]
+
 use std::fmt;
 use std::net::SocketAddr;
 use thiserror::Error;
@@ -89,7 +91,7 @@ impl From<StreamError> for std::io::Error {
                 std::io::Error::new(std::io::ErrorKind::UnexpectedEof, err)
             }
             StreamError::Poisoned { .. } => {
-                std::io::Error::new(std::io::ErrorKind::Other, err)
+                std::io::Error::other(err)
             }
             StreamError::BufferOverflow { .. } => {
                 std::io::Error::new(std::io::ErrorKind::OutOfMemory, err)
@@ -98,7 +100,7 @@ impl From<StreamError> for std::io::Error {
                 std::io::Error::new(std::io::ErrorKind::InvalidData, err)
             }
             StreamError::PartialRead { .. } | StreamError::PartialWrite { .. } => {
-                std::io::Error::new(std::io::ErrorKind::Other, err)
+                std::io::Error::other(err)
             }
         }
     }
@@ -133,12 +135,7 @@ impl Recoverable for StreamError {
     }
     
     fn can_continue(&self) -> bool {
-        match self {
-            Self::Poisoned { .. } => false,
-            Self::UnexpectedEof => false,
-            Self::BufferOverflow { .. } => false,
-            _ => true,
-        }
+        !matches!(self, Self::Poisoned { .. } | Self::UnexpectedEof | Self::BufferOverflow { .. })
     }
 }
 

src/ip_tracker.rs

@@ -1,250 +1,278 @@
-// src/ip_tracker.rs
-// Модуль для отслеживания и ограничения уникальных IP-адресов пользователей
+// IP address tracking and per-user unique IP limiting.
 
-use std::collections::{HashMap, HashSet};
+#![allow(dead_code)]
+
+use std::collections::HashMap;
 use std::net::IpAddr;
 use std::sync::Arc;
+use std::time::{Duration, Instant};
+
 use tokio::sync::RwLock;
 
-/// Трекер уникальных IP-адресов для каждого пользователя MTProxy
-/// 
-/// Предоставляет thread-safe механизм для:
-/// - Отслеживания активных IP-адресов каждого пользователя
-/// - Ограничения количества уникальных IP на пользователя
-/// - Автоматической очистки при отключении клиентов
+use crate::config::UserMaxUniqueIpsMode;
+
 #[derive(Debug, Clone)]
 pub struct UserIpTracker {
-    /// Маппинг: Имя пользователя -> Множество активных IP-адресов
-    active_ips: Arc<RwLock<HashMap<String, HashSet<IpAddr>>>>,
-    
-    /// Маппинг: Имя пользователя -> Максимально разрешенное количество уникальных IP
+    active_ips: Arc<RwLock<HashMap<String, HashMap<IpAddr, usize>>>>,
+    recent_ips: Arc<RwLock<HashMap<String, HashMap<IpAddr, Instant>>>>,
     max_ips: Arc<RwLock<HashMap<String, usize>>>,
+    limit_mode: Arc<RwLock<UserMaxUniqueIpsMode>>,
+    limit_window: Arc<RwLock<Duration>>,
 }
 
 impl UserIpTracker {
-    /// Создать новый пустой трекер
     pub fn new() -> Self {
         Self {
             active_ips: Arc::new(RwLock::new(HashMap::new())),
+            recent_ips: Arc::new(RwLock::new(HashMap::new())),
             max_ips: Arc::new(RwLock::new(HashMap::new())),
+            limit_mode: Arc::new(RwLock::new(UserMaxUniqueIpsMode::ActiveWindow)),
+            limit_window: Arc::new(RwLock::new(Duration::from_secs(30))),
         }
     }
 
-    /// Установить лимит уникальных IP для конкретного пользователя
-    /// 
-    /// # Arguments
-    /// * `username` - Имя пользователя
-    /// * `max_ips` - Максимальное количество одновременно активных IP-адресов
+    pub async fn set_limit_policy(&self, mode: UserMaxUniqueIpsMode, window_secs: u64) {
+        {
+            let mut current_mode = self.limit_mode.write().await;
+            *current_mode = mode;
+        }
+        let mut current_window = self.limit_window.write().await;
+        *current_window = Duration::from_secs(window_secs.max(1));
+    }
+
     pub async fn set_user_limit(&self, username: &str, max_ips: usize) {
         let mut limits = self.max_ips.write().await;
         limits.insert(username.to_string(), max_ips);
     }
 
-    /// Загрузить лимиты из конфигурации
-    /// 
-    /// # Arguments
-    /// * `limits` - HashMap с лимитами из config.toml
-    pub async fn load_limits(&self, limits: &HashMap<String, usize>) {
-        let mut max_ips = self.max_ips.write().await;
-        for (user, limit) in limits {
-            max_ips.insert(user.clone(), *limit);
-        }
+    pub async fn remove_user_limit(&self, username: &str) {
+        let mut limits = self.max_ips.write().await;
+        limits.remove(username);
+    }
+
+    pub async fn load_limits(&self, limits: &HashMap<String, usize>) {
+        let mut max_ips = self.max_ips.write().await;
+        max_ips.clone_from(limits);
+    }
+
+    fn prune_recent(user_recent: &mut HashMap<IpAddr, Instant>, now: Instant, window: Duration) {
+        if user_recent.is_empty() {
+            return;
+        }
+        user_recent.retain(|_, seen_at| now.duration_since(*seen_at) <= window);
     }
 
-    /// Проверить, может ли пользователь подключиться с данного IP-адреса
-    /// и добавить IP в список активных, если проверка успешна
-    /// 
-    /// # Arguments
-    /// * `username` - Имя пользователя
-    /// * `ip` - IP-адрес клиента
-    /// 
-    /// # Returns
-    /// * `Ok(())` - Подключение разрешено, IP добавлен в активные
-    /// * `Err(String)` - Подключение отклонено с описанием причины
     pub async fn check_and_add(&self, username: &str, ip: IpAddr) -> Result<(), String> {
-        // Получаем лимит для пользователя
-        let max_ips = self.max_ips.read().await;
-        let limit = match max_ips.get(username) {
-            Some(limit) => *limit,
-            None => {
-                // Если лимит не задан - разрешаем безлимитный доступ
-                drop(max_ips);
-                let mut active_ips = self.active_ips.write().await;
-                let user_ips = active_ips
-                    .entry(username.to_string())
-                    .or_insert_with(HashSet::new);
-                user_ips.insert(ip);
-                return Ok(());
-            }
+        let limit = {
+            let max_ips = self.max_ips.read().await;
+            max_ips.get(username).copied()
         };
-        drop(max_ips);
+        let mode = *self.limit_mode.read().await;
+        let window = *self.limit_window.read().await;
+        let now = Instant::now();
 
-        // Проверяем и обновляем активные IP
         let mut active_ips = self.active_ips.write().await;
-        let user_ips = active_ips
+        let user_active = active_ips
             .entry(username.to_string())
-            .or_insert_with(HashSet::new);
+            .or_insert_with(HashMap::new);
 
-        // Если IP уже есть в списке - это повторное подключение, разрешаем
-        if user_ips.contains(&ip) {
+        let mut recent_ips = self.recent_ips.write().await;
+        let user_recent = recent_ips
+            .entry(username.to_string())
+            .or_insert_with(HashMap::new);
+        Self::prune_recent(user_recent, now, window);
+
+        if let Some(count) = user_active.get_mut(&ip) {
+            *count = count.saturating_add(1);
+            user_recent.insert(ip, now);
             return Ok(());
         }
 
-        // Проверяем, не превышен ли лимит
-        if user_ips.len() >= limit {
-            return Err(format!(
-                "IP limit reached for user '{}': {}/{} unique IPs already connected",
-                username,
-                user_ips.len(),
-                limit
-            ));
+        if let Some(limit) = limit {
+            let active_limit_reached = user_active.len() >= limit;
+            let recent_limit_reached = user_recent.len() >= limit;
+            let deny = match mode {
+                UserMaxUniqueIpsMode::ActiveWindow => active_limit_reached,
+                UserMaxUniqueIpsMode::TimeWindow => recent_limit_reached,
+                UserMaxUniqueIpsMode::Combined => active_limit_reached || recent_limit_reached,
+            };
+
+            if deny {
+                return Err(format!(
+                    "IP limit reached for user '{}': active={}/{} recent={}/{} mode={:?}",
+                    username,
+                    user_active.len(),
+                    limit,
+                    user_recent.len(),
+                    limit,
+                    mode
+                ));
+            }
         }
 
-        // Лимит не превышен - добавляем новый IP
-        user_ips.insert(ip);
+        user_active.insert(ip, 1);
+        user_recent.insert(ip, now);
         Ok(())
     }
 
-    /// Удалить IP-адрес из списка активных при отключении клиента
-    /// 
-    /// # Arguments
-    /// * `username` - Имя пользователя
-    /// * `ip` - IP-адрес отключившегося клиента
     pub async fn remove_ip(&self, username: &str, ip: IpAddr) {
         let mut active_ips = self.active_ips.write().await;
-        
         if let Some(user_ips) = active_ips.get_mut(username) {
-            user_ips.remove(&ip);
-            
-            // Если у пользователя не осталось активных IP - удаляем запись
-            // для экономии памяти
+            if let Some(count) = user_ips.get_mut(&ip) {
+                if *count > 1 {
+                    *count -= 1;
+                } else {
+                    user_ips.remove(&ip);
+                }
+            }
             if user_ips.is_empty() {
                 active_ips.remove(username);
             }
         }
     }
 
-    /// Получить текущее количество активных IP-адресов для пользователя
-    /// 
-    /// # Arguments
-    /// * `username` - Имя пользователя
-    /// 
-    /// # Returns
-    /// Количество уникальных активных IP-адресов
-    pub async fn get_active_ip_count(&self, username: &str) -> usize {
-        let active_ips = self.active_ips.read().await;
-        active_ips
-            .get(username)
-            .map(|ips| ips.len())
-            .unwrap_or(0)
+    pub async fn get_recent_counts_for_users(&self, users: &[String]) -> HashMap<String, usize> {
+        let window = *self.limit_window.read().await;
+        let now = Instant::now();
+        let recent_ips = self.recent_ips.read().await;
+
+        let mut counts = HashMap::with_capacity(users.len());
+        for user in users {
+            let count = if let Some(user_recent) = recent_ips.get(user) {
+                user_recent
+                    .values()
+                    .filter(|seen_at| now.duration_since(**seen_at) <= window)
+                    .count()
+            } else {
+                0
+            };
+            counts.insert(user.clone(), count);
+        }
+        counts
+    }
+
+    pub async fn get_active_ips_for_users(&self, users: &[String]) -> HashMap<String, Vec<IpAddr>> {
+        let active_ips = self.active_ips.read().await;
+        let mut out = HashMap::with_capacity(users.len());
+        for user in users {
+            let mut ips = active_ips
+                .get(user)
+                .map(|per_ip| per_ip.keys().copied().collect::<Vec<_>>())
+                .unwrap_or_else(Vec::new);
+            ips.sort();
+            out.insert(user.clone(), ips);
+        }
+        out
+    }
+
+    pub async fn get_recent_ips_for_users(&self, users: &[String]) -> HashMap<String, Vec<IpAddr>> {
+        let window = *self.limit_window.read().await;
+        let now = Instant::now();
+        let recent_ips = self.recent_ips.read().await;
+
+        let mut out = HashMap::with_capacity(users.len());
+        for user in users {
+            let mut ips = if let Some(user_recent) = recent_ips.get(user) {
+                user_recent
+                    .iter()
+                    .filter(|(_, seen_at)| now.duration_since(**seen_at) <= window)
+                    .map(|(ip, _)| *ip)
+                    .collect::<Vec<_>>()
+            } else {
+                Vec::new()
+            };
+            ips.sort();
+            out.insert(user.clone(), ips);
+        }
+        out
+    }
+
+    pub async fn get_active_ip_count(&self, username: &str) -> usize {
+        let active_ips = self.active_ips.read().await;
+        active_ips.get(username).map(|ips| ips.len()).unwrap_or(0)
     }
 
-    /// Получить список всех активных IP-адресов для пользователя
-    /// 
-    /// # Arguments
-    /// * `username` - Имя пользователя
-    /// 
-    /// # Returns
-    /// Вектор с активными IP-адресами
     pub async fn get_active_ips(&self, username: &str) -> Vec<IpAddr> {
         let active_ips = self.active_ips.read().await;
         active_ips
             .get(username)
-            .map(|ips| ips.iter().copied().collect())
+            .map(|ips| ips.keys().copied().collect())
             .unwrap_or_else(Vec::new)
     }
 
-    /// Получить статистику по всем пользователям
-    /// 
-    /// # Returns
-    /// Вектор кортежей: (имя_пользователя, количество_активных_IP, лимит)
     pub async fn get_stats(&self) -> Vec<(String, usize, usize)> {
         let active_ips = self.active_ips.read().await;
         let max_ips = self.max_ips.read().await;
 
         let mut stats = Vec::new();
-        
-        // Собираем статистику по пользователям с активными подключениями
         for (username, user_ips) in active_ips.iter() {
             let limit = max_ips.get(username).copied().unwrap_or(0);
             stats.push((username.clone(), user_ips.len(), limit));
         }
-        
-        stats.sort_by(|a, b| a.0.cmp(&b.0)); // Сортируем по имени пользователя
+
+        stats.sort_by(|a, b| a.0.cmp(&b.0));
         stats
     }
 
-    /// Очистить все активные IP для пользователя (при необходимости)
-    /// 
-    /// # Arguments
-    /// * `username` - Имя пользователя
     pub async fn clear_user_ips(&self, username: &str) {
         let mut active_ips = self.active_ips.write().await;
         active_ips.remove(username);
+        drop(active_ips);
+
+        let mut recent_ips = self.recent_ips.write().await;
+        recent_ips.remove(username);
     }
 
-    /// Очистить всю статистику (использовать с осторожностью!)
     pub async fn clear_all(&self) {
         let mut active_ips = self.active_ips.write().await;
         active_ips.clear();
+        drop(active_ips);
+
+        let mut recent_ips = self.recent_ips.write().await;
+        recent_ips.clear();
     }
 
-    /// Проверить, подключен ли пользователь с данного IP
-    /// 
-    /// # Arguments
-    /// * `username` - Имя пользователя
-    /// * `ip` - IP-адрес для проверки
-    /// 
-    /// # Returns
-    /// `true` если IP активен, `false` если нет
     pub async fn is_ip_active(&self, username: &str, ip: IpAddr) -> bool {
         let active_ips = self.active_ips.read().await;
         active_ips
             .get(username)
-            .map(|ips| ips.contains(&ip))
+            .map(|ips| ips.contains_key(&ip))
             .unwrap_or(false)
     }
 
-    /// Получить лимит для пользователя
-    /// 
-    /// # Arguments
-    /// * `username` - Имя пользователя
-    /// 
-    /// # Returns
-    /// Лимит IP-адресов или None, если лимит не установлен
     pub async fn get_user_limit(&self, username: &str) -> Option<usize> {
         let max_ips = self.max_ips.read().await;
         max_ips.get(username).copied()
     }
 
-    /// Форматировать статистику в читаемый текст
-    /// 
-    /// # Returns
-    /// Строка со статистикой для логов или мониторинга
     pub async fn format_stats(&self) -> String {
         let stats = self.get_stats().await;
-        
+
         if stats.is_empty() {
             return String::from("No active users");
         }
-        
+
         let mut output = String::from("User IP Statistics:\n");
         output.push_str("==================\n");
-        
+
         for (username, active_count, limit) in stats {
             output.push_str(&format!(
                 "User: {:<20} Active IPs: {}/{}\n",
                 username,
                 active_count,
-                if limit > 0 { limit.to_string() } else { "unlimited".to_string() }
+                if limit > 0 {
+                    limit.to_string()
+                } else {
+                    "unlimited".to_string()
+                }
             ));
-            
+
             let ips = self.get_active_ips(&username).await;
             for ip in ips {
-                output.push_str(&format!("  └─ {}\n", ip));
+                output.push_str(&format!("  - {}\n", ip));
             }
         }
-        
+
         output
     }
 }
@@ -255,10 +283,6 @@ impl Default for UserIpTracker {
     }
 }
 
-// ============================================================================
-// ТЕСТЫ
-// ============================================================================
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -281,17 +305,33 @@ mod tests {
         let ip2 = test_ipv4(192, 168, 1, 2);
         let ip3 = test_ipv4(192, 168, 1, 3);
 
-        // Первые два IP должны быть приняты
         assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
         assert!(tracker.check_and_add("test_user", ip2).await.is_ok());
-
-        // Третий IP должен быть отклонен
         assert!(tracker.check_and_add("test_user", ip3).await.is_err());
 
-        // Проверяем счетчик
         assert_eq!(tracker.get_active_ip_count("test_user").await, 2);
     }
 
+    #[tokio::test]
+    async fn test_active_window_rejects_new_ip_and_keeps_existing_session() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 1).await;
+        tracker
+            .set_limit_policy(UserMaxUniqueIpsMode::ActiveWindow, 30)
+            .await;
+
+        let ip1 = test_ipv4(10, 10, 10, 1);
+        let ip2 = test_ipv4(10, 10, 10, 2);
+
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        assert!(tracker.is_ip_active("test_user", ip1).await);
+        assert!(tracker.check_and_add("test_user", ip2).await.is_err());
+
+        // Existing session remains active; only new unique IP is denied.
+        assert!(tracker.is_ip_active("test_user", ip1).await);
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 1);
+    }
+
     #[tokio::test]
     async fn test_reconnection_from_same_ip() {
         let tracker = UserIpTracker::new();
@@ -299,16 +339,29 @@ mod tests {
 
         let ip1 = test_ipv4(192, 168, 1, 1);
 
-        // Первое подключение
         assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
-        
-        // Повторное подключение с того же IP должно пройти
         assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
-        
-        // Счетчик не должен увеличиться
         assert_eq!(tracker.get_active_ip_count("test_user").await, 1);
     }
 
+    #[tokio::test]
+    async fn test_same_ip_disconnect_keeps_active_while_other_session_alive() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 2).await;
+
+        let ip1 = test_ipv4(192, 168, 1, 1);
+
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 1);
+
+        tracker.remove_ip("test_user", ip1).await;
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 1);
+
+        tracker.remove_ip("test_user", ip1).await;
+        assert_eq!(tracker.get_active_ip_count("test_user").await, 0);
+    }
+
     #[tokio::test]
     async fn test_ip_removal() {
         let tracker = UserIpTracker::new();
@@ -318,36 +371,28 @@ mod tests {
         let ip2 = test_ipv4(192, 168, 1, 2);
         let ip3 = test_ipv4(192, 168, 1, 3);
 
-        // Добавляем два IP
         assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
         assert!(tracker.check_and_add("test_user", ip2).await.is_ok());
-        
-        // Третий не должен пройти
         assert!(tracker.check_and_add("test_user", ip3).await.is_err());
 
-        // Удаляем первый IP
         tracker.remove_ip("test_user", ip1).await;
-        
-        // Теперь третий должен пройти
+
         assert!(tracker.check_and_add("test_user", ip3).await.is_ok());
-        
         assert_eq!(tracker.get_active_ip_count("test_user").await, 2);
     }
 
     #[tokio::test]
     async fn test_no_limit() {
         let tracker = UserIpTracker::new();
-        // Не устанавливаем лимит для test_user
 
         let ip1 = test_ipv4(192, 168, 1, 1);
         let ip2 = test_ipv4(192, 168, 1, 2);
         let ip3 = test_ipv4(192, 168, 1, 3);
 
-        // Без лимита все IP должны проходить
         assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
         assert!(tracker.check_and_add("test_user", ip2).await.is_ok());
         assert!(tracker.check_and_add("test_user", ip3).await.is_ok());
-        
+
         assert_eq!(tracker.get_active_ip_count("test_user").await, 3);
     }
 
@@ -360,11 +405,9 @@ mod tests {
         let ip1 = test_ipv4(192, 168, 1, 1);
         let ip2 = test_ipv4(192, 168, 1, 2);
 
-        // user1 может использовать 2 IP
         assert!(tracker.check_and_add("user1", ip1).await.is_ok());
         assert!(tracker.check_and_add("user1", ip2).await.is_ok());
 
-        // user2 может использовать только 1 IP
         assert!(tracker.check_and_add("user2", ip1).await.is_ok());
         assert!(tracker.check_and_add("user2", ip2).await.is_err());
     }
@@ -377,10 +420,9 @@ mod tests {
         let ipv4 = test_ipv4(192, 168, 1, 1);
         let ipv6 = test_ipv6();
 
-        // Должны работать оба типа адресов
         assert!(tracker.check_and_add("test_user", ipv4).await.is_ok());
         assert!(tracker.check_and_add("test_user", ipv6).await.is_ok());
-        
+
         assert_eq!(tracker.get_active_ip_count("test_user").await, 2);
     }
 
@@ -415,8 +457,7 @@ mod tests {
 
         let stats = tracker.get_stats().await;
         assert_eq!(stats.len(), 2);
-        
-        // Проверяем наличие обоих пользователей в статистике
+
         assert!(stats.iter().any(|(name, _, _)| name == "user1"));
         assert!(stats.iter().any(|(name, _, _)| name == "user2"));
     }
@@ -425,10 +466,10 @@ mod tests {
     async fn test_clear_user_ips() {
         let tracker = UserIpTracker::new();
         let ip1 = test_ipv4(192, 168, 1, 1);
-        
+
         tracker.check_and_add("test_user", ip1).await.unwrap();
         assert_eq!(tracker.get_active_ip_count("test_user").await, 1);
-        
+
         tracker.clear_user_ips("test_user").await;
         assert_eq!(tracker.get_active_ip_count("test_user").await, 0);
     }
@@ -438,9 +479,9 @@ mod tests {
         let tracker = UserIpTracker::new();
         let ip1 = test_ipv4(192, 168, 1, 1);
         let ip2 = test_ipv4(192, 168, 1, 2);
-        
+
         tracker.check_and_add("test_user", ip1).await.unwrap();
-        
+
         assert!(tracker.is_ip_active("test_user", ip1).await);
         assert!(!tracker.is_ip_active("test_user", ip2).await);
     }
@@ -448,15 +489,85 @@ mod tests {
     #[tokio::test]
     async fn test_load_limits_from_config() {
         let tracker = UserIpTracker::new();
-        
+
         let mut config_limits = HashMap::new();
         config_limits.insert("user1".to_string(), 5);
         config_limits.insert("user2".to_string(), 3);
-        
+
         tracker.load_limits(&config_limits).await;
-        
+
         assert_eq!(tracker.get_user_limit("user1").await, Some(5));
         assert_eq!(tracker.get_user_limit("user2").await, Some(3));
         assert_eq!(tracker.get_user_limit("user3").await, None);
     }
+
+    #[tokio::test]
+    async fn test_load_limits_replaces_previous_map() {
+        let tracker = UserIpTracker::new();
+
+        let mut first = HashMap::new();
+        first.insert("user1".to_string(), 2);
+        first.insert("user2".to_string(), 3);
+        tracker.load_limits(&first).await;
+
+        let mut second = HashMap::new();
+        second.insert("user2".to_string(), 5);
+        tracker.load_limits(&second).await;
+
+        assert_eq!(tracker.get_user_limit("user1").await, None);
+        assert_eq!(tracker.get_user_limit("user2").await, Some(5));
+    }
+
+    #[tokio::test]
+    async fn test_time_window_mode_blocks_recent_ip_churn() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 1).await;
+        tracker
+            .set_limit_policy(UserMaxUniqueIpsMode::TimeWindow, 30)
+            .await;
+
+        let ip1 = test_ipv4(10, 0, 0, 1);
+        let ip2 = test_ipv4(10, 0, 0, 2);
+
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        tracker.remove_ip("test_user", ip1).await;
+        assert!(tracker.check_and_add("test_user", ip2).await.is_err());
+    }
+
+    #[tokio::test]
+    async fn test_combined_mode_enforces_active_and_recent_limits() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 1).await;
+        tracker
+            .set_limit_policy(UserMaxUniqueIpsMode::Combined, 30)
+            .await;
+
+        let ip1 = test_ipv4(10, 0, 1, 1);
+        let ip2 = test_ipv4(10, 0, 1, 2);
+
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ip2).await.is_err());
+
+        tracker.remove_ip("test_user", ip1).await;
+        assert!(tracker.check_and_add("test_user", ip2).await.is_err());
+    }
+
+    #[tokio::test]
+    async fn test_time_window_expires() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 1).await;
+        tracker
+            .set_limit_policy(UserMaxUniqueIpsMode::TimeWindow, 1)
+            .await;
+
+        let ip1 = test_ipv4(10, 1, 0, 1);
+        let ip2 = test_ipv4(10, 1, 0, 2);
+
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        tracker.remove_ip("test_user", ip1).await;
+        assert!(tracker.check_and_add("test_user", ip2).await.is_err());
+
+        tokio::time::sleep(Duration::from_millis(1100)).await;
+        assert!(tracker.check_and_add("test_user", ip2).await.is_ok());
+    }
 }

src/network/dns_overrides.rs

@@ -0,0 +1,197 @@
+//! Runtime DNS overrides for `host:port` targets.
+
+use std::collections::HashMap;
+use std::net::{IpAddr, Ipv6Addr, SocketAddr};
+use std::sync::{OnceLock, RwLock};
+
+use crate::error::{ProxyError, Result};
+
+type OverrideMap = HashMap<(String, u16), IpAddr>;
+
+static DNS_OVERRIDES: OnceLock<RwLock<OverrideMap>> = OnceLock::new();
+
+fn overrides_store() -> &'static RwLock<OverrideMap> {
+    DNS_OVERRIDES.get_or_init(|| RwLock::new(HashMap::new()))
+}
+
+fn parse_ip_spec(ip_spec: &str) -> Result<IpAddr> {
+    if ip_spec.starts_with('[') && ip_spec.ends_with(']') {
+        let inner = &ip_spec[1..ip_spec.len() - 1];
+        let ipv6 = inner.parse::<Ipv6Addr>().map_err(|_| {
+            ProxyError::Config(format!(
+                "network.dns_overrides IPv6 override is invalid: '{ip_spec}'"
+            ))
+        })?;
+        return Ok(IpAddr::V6(ipv6));
+    }
+
+    let ip = ip_spec.parse::<IpAddr>().map_err(|_| {
+        ProxyError::Config(format!(
+            "network.dns_overrides IP is invalid: '{ip_spec}'"
+        ))
+    })?;
+    if matches!(ip, IpAddr::V6(_)) {
+        return Err(ProxyError::Config(format!(
+            "network.dns_overrides IPv6 must be bracketed: '{ip_spec}'"
+        )));
+    }
+    Ok(ip)
+}
+
+fn parse_entry(entry: &str) -> Result<((String, u16), IpAddr)> {
+    let trimmed = entry.trim();
+    if trimmed.is_empty() {
+        return Err(ProxyError::Config(
+            "network.dns_overrides entry cannot be empty".to_string(),
+        ));
+    }
+
+    let first_sep = trimmed.find(':').ok_or_else(|| {
+        ProxyError::Config(format!(
+            "network.dns_overrides entry must use host:port:ip format: '{trimmed}'"
+        ))
+    })?;
+    let second_sep = trimmed[first_sep + 1..]
+        .find(':')
+        .map(|idx| first_sep + 1 + idx)
+        .ok_or_else(|| {
+            ProxyError::Config(format!(
+                "network.dns_overrides entry must use host:port:ip format: '{trimmed}'"
+            ))
+        })?;
+
+    let host = trimmed[..first_sep].trim();
+    let port_str = trimmed[first_sep + 1..second_sep].trim();
+    let ip_str = trimmed[second_sep + 1..].trim();
+
+    if host.is_empty() {
+        return Err(ProxyError::Config(format!(
+            "network.dns_overrides host cannot be empty: '{trimmed}'"
+        )));
+    }
+    if host.contains(':') {
+        return Err(ProxyError::Config(format!(
+            "network.dns_overrides host must be a domain name without ':' in this format: '{trimmed}'"
+        )));
+    }
+
+    let port = port_str.parse::<u16>().map_err(|_| {
+        ProxyError::Config(format!(
+            "network.dns_overrides port is invalid: '{trimmed}'"
+        ))
+    })?;
+    let ip = parse_ip_spec(ip_str)?;
+
+    Ok(((host.to_ascii_lowercase(), port), ip))
+}
+
+fn parse_entries(entries: &[String]) -> Result<OverrideMap> {
+    let mut parsed = HashMap::new();
+    for entry in entries {
+        let (key, ip) = parse_entry(entry)?;
+        parsed.insert(key, ip);
+    }
+    Ok(parsed)
+}
+
+/// Validate `network.dns_overrides` entries without updating runtime state.
+pub fn validate_entries(entries: &[String]) -> Result<()> {
+    let _ = parse_entries(entries)?;
+    Ok(())
+}
+
+/// Replace runtime DNS overrides with a new validated snapshot.
+pub fn install_entries(entries: &[String]) -> Result<()> {
+    let parsed = parse_entries(entries)?;
+    let mut guard = overrides_store()
+        .write()
+        .map_err(|_| ProxyError::Config("network.dns_overrides runtime lock is poisoned".to_string()))?;
+    *guard = parsed;
+    Ok(())
+}
+
+/// Resolve a hostname override for `(host, port)` if present.
+pub fn resolve(host: &str, port: u16) -> Option<IpAddr> {
+    let key = (host.to_ascii_lowercase(), port);
+    overrides_store()
+        .read()
+        .ok()
+        .and_then(|guard| guard.get(&key).copied())
+}
+
+/// Resolve a hostname override and construct a socket address when present.
+pub fn resolve_socket_addr(host: &str, port: u16) -> Option<SocketAddr> {
+    resolve(host, port).map(|ip| SocketAddr::new(ip, port))
+}
+
+/// Parse a runtime endpoint in `host:port` format.
+///
+/// Supports:
+/// - `example.com:443`
+/// - `[2001:db8::1]:443`
+pub fn split_host_port(endpoint: &str) -> Option<(String, u16)> {
+    if endpoint.starts_with('[') {
+        let bracket_end = endpoint.find(']')?;
+        if endpoint.as_bytes().get(bracket_end + 1) != Some(&b':') {
+            return None;
+        }
+        let host = endpoint[1..bracket_end].trim();
+        let port = endpoint[bracket_end + 2..].trim().parse::<u16>().ok()?;
+        if host.is_empty() {
+            return None;
+        }
+        return Some((host.to_ascii_lowercase(), port));
+    }
+
+    let split_idx = endpoint.rfind(':')?;
+    let host = endpoint[..split_idx].trim();
+    let port = endpoint[split_idx + 1..].trim().parse::<u16>().ok()?;
+    if host.is_empty() || host.contains(':') {
+        return None;
+    }
+
+    Some((host.to_ascii_lowercase(), port))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn validate_accepts_ipv4_and_bracketed_ipv6() {
+        let entries = vec![
+            "example.com:443:127.0.0.1".to_string(),
+            "example.net:8443:[2001:db8::10]".to_string(),
+        ];
+        assert!(validate_entries(&entries).is_ok());
+    }
+
+    #[test]
+    fn validate_rejects_unbracketed_ipv6() {
+        let entries = vec!["example.net:443:2001:db8::10".to_string()];
+        let err = validate_entries(&entries).unwrap_err().to_string();
+        assert!(err.contains("must be bracketed"));
+    }
+
+    #[test]
+    fn install_and_resolve_are_case_insensitive_for_host() {
+        let entries = vec!["MyPetrovich.ru:8443:127.0.0.1".to_string()];
+        install_entries(&entries).unwrap();
+
+        let resolved = resolve("mypetrovich.ru", 8443);
+        assert_eq!(resolved, Some("127.0.0.1".parse().unwrap()));
+    }
+
+    #[test]
+    fn split_host_port_parses_supported_shapes() {
+        assert_eq!(
+            split_host_port("example.com:443"),
+            Some(("example.com".to_string(), 443))
+        );
+        assert_eq!(
+            split_host_port("[2001:db8::1]:443"),
+            Some(("2001:db8::1".to_string(), 443))
+        );
+        assert_eq!(split_host_port("2001:db8::1:443"), None);
+    }
+}

src/network/mod.rs

@@ -1,3 +1,4 @@
+pub mod dns_overrides;
 pub mod probe;
 pub mod stun;
 

src/network/probe.rs

@@ -1,10 +1,16 @@
-use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, UdpSocket};
+#![allow(dead_code)]
 
-use tracing::{info, warn};
+use std::collections::HashMap;
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, UdpSocket};
+use std::time::Duration;
+
+use tokio::task::JoinSet;
+use tokio::time::timeout;
+use tracing::{debug, info, warn};
 
 use crate::config::NetworkConfig;
 use crate::error::Result;
-use crate::network::stun::{stun_probe_dual, DualStunResult, IpFamily};
+use crate::network::stun::{stun_probe_dual, DualStunResult, IpFamily, StunProbeResult};
 
 #[derive(Debug, Clone, Default)]
 pub struct NetworkProbe {
@@ -47,7 +53,13 @@ impl NetworkDecision {
     }
 }
 
-pub async fn run_probe(config: &NetworkConfig, stun_addr: Option<String>, nat_probe: bool) -> Result<NetworkProbe> {
+const STUN_BATCH_TIMEOUT: Duration = Duration::from_secs(5);
+
+pub async fn run_probe(
+    config: &NetworkConfig,
+    nat_probe: bool,
+    stun_nat_probe_concurrency: usize,
+) -> Result<NetworkProbe> {
     let mut probe = NetworkProbe::default();
 
     probe.detected_ipv4 = detect_local_ip_v4();
@@ -56,21 +68,38 @@ pub async fn run_probe(config: &NetworkConfig, stun_addr: Option<String>, nat_pr
     probe.ipv4_is_bogon = probe.detected_ipv4.map(is_bogon_v4).unwrap_or(false);
     probe.ipv6_is_bogon = probe.detected_ipv6.map(is_bogon_v6).unwrap_or(false);
 
-    let stun_server = stun_addr.unwrap_or_else(|| "stun.l.google.com:19302".to_string());
-    let stun_res = if nat_probe {
-        match stun_probe_dual(&stun_server).await {
-            Ok(res) => res,
-            Err(e) => {
-                warn!(error = %e, "STUN probe failed, continuing without reflection");
-                DualStunResult::default()
-            }
+    let stun_res = if nat_probe && config.stun_use {
+        let servers = collect_stun_servers(config);
+        if servers.is_empty() {
+            warn!("STUN probe is enabled but network.stun_servers is empty");
+            DualStunResult::default()
+        } else {
+            probe_stun_servers_parallel(
+                &servers,
+                stun_nat_probe_concurrency.max(1),
+            )
+            .await
         }
+    } else if nat_probe {
+        info!("STUN probe is disabled by network.stun_use=false");
+        DualStunResult::default()
     } else {
         DualStunResult::default()
     };
     probe.reflected_ipv4 = stun_res.v4.map(|r| r.reflected_addr);
     probe.reflected_ipv6 = stun_res.v6.map(|r| r.reflected_addr);
 
+    // If STUN is blocked but IPv4 is private, try HTTP public-IP fallback.
+    if nat_probe
+        && probe.reflected_ipv4.is_none()
+        && probe.detected_ipv4.map(is_bogon_v4).unwrap_or(false)
+    {
+        if let Some(public_ip) = detect_public_ipv4_http(&config.http_ip_detect_urls).await {
+            probe.reflected_ipv4 = Some(SocketAddr::new(IpAddr::V4(public_ip), 0));
+            info!(public_ip = %public_ip, "STUN unavailable, using HTTP public IPv4 fallback");
+        }
+    }
+
     probe.ipv4_nat_detected = match (probe.detected_ipv4, probe.reflected_ipv4) {
         (Some(det), Some(reflected)) => det != reflected.ip(),
         _ => false,
@@ -92,24 +121,127 @@ pub async fn run_probe(config: &NetworkConfig, stun_addr: Option<String>, nat_pr
     Ok(probe)
 }
 
+async fn detect_public_ipv4_http(urls: &[String]) -> Option<Ipv4Addr> {
+    let client = reqwest::Client::builder()
+        .timeout(Duration::from_secs(3))
+        .build()
+        .ok()?;
+
+    for url in urls {
+        let response = match client.get(url).send().await {
+            Ok(response) => response,
+            Err(_) => continue,
+        };
+
+        let body = match response.text().await {
+            Ok(body) => body,
+            Err(_) => continue,
+        };
+
+        let Ok(ip) = body.trim().parse::<Ipv4Addr>() else {
+            continue;
+        };
+        if !is_bogon_v4(ip) {
+            return Some(ip);
+        }
+    }
+
+    None
+}
+
+fn collect_stun_servers(config: &NetworkConfig) -> Vec<String> {
+    let mut out = Vec::new();
+    for s in &config.stun_servers {
+        if !s.is_empty() && !out.contains(s) {
+            out.push(s.clone());
+        }
+    }
+    out
+}
+
+async fn probe_stun_servers_parallel(
+    servers: &[String],
+    concurrency: usize,
+) -> DualStunResult {
+    let mut join_set = JoinSet::new();
+    let mut next_idx = 0usize;
+    let mut best_v4_by_ip: HashMap<IpAddr, (usize, StunProbeResult)> = HashMap::new();
+    let mut best_v6_by_ip: HashMap<IpAddr, (usize, StunProbeResult)> = HashMap::new();
+
+    while next_idx < servers.len() || !join_set.is_empty() {
+        while next_idx < servers.len() && join_set.len() < concurrency {
+            let stun_addr = servers[next_idx].clone();
+            next_idx += 1;
+            join_set.spawn(async move {
+                let res = timeout(STUN_BATCH_TIMEOUT, stun_probe_dual(&stun_addr)).await;
+                (stun_addr, res)
+            });
+        }
+
+        let Some(task) = join_set.join_next().await else {
+            break;
+        };
+
+        match task {
+            Ok((stun_addr, Ok(Ok(result)))) => {
+                if let Some(v4) = result.v4 {
+                    let entry = best_v4_by_ip.entry(v4.reflected_addr.ip()).or_insert((0, v4));
+                    entry.0 += 1;
+                }
+                if let Some(v6) = result.v6 {
+                    let entry = best_v6_by_ip.entry(v6.reflected_addr.ip()).or_insert((0, v6));
+                    entry.0 += 1;
+                }
+                if result.v4.is_some() || result.v6.is_some() {
+                    debug!(stun = %stun_addr, "STUN server responded within probe timeout");
+                }
+            }
+            Ok((stun_addr, Ok(Err(e)))) => {
+                debug!(error = %e, stun = %stun_addr, "STUN probe failed");
+            }
+            Ok((stun_addr, Err(_))) => {
+                debug!(stun = %stun_addr, "STUN probe timeout");
+            }
+            Err(e) => {
+                debug!(error = %e, "STUN probe task join failed");
+            }
+        }
+    }
+
+    let mut out = DualStunResult::default();
+    if let Some((_, best)) = best_v4_by_ip
+        .into_values()
+        .max_by_key(|(count, _)| *count)
+    {
+        info!("STUN-Quorum reached, IP: {}", best.reflected_addr.ip());
+        out.v4 = Some(best);
+    }
+    if let Some((_, best)) = best_v6_by_ip
+        .into_values()
+        .max_by_key(|(count, _)| *count)
+    {
+        info!("STUN-Quorum reached, IP: {}", best.reflected_addr.ip());
+        out.v6 = Some(best);
+    }
+    out
+}
+
 pub fn decide_network_capabilities(config: &NetworkConfig, probe: &NetworkProbe) -> NetworkDecision {
-    let mut decision = NetworkDecision::default();
+    let ipv4_dc = config.ipv4 && probe.detected_ipv4.is_some();
+    let ipv6_dc = config.ipv6.unwrap_or(probe.detected_ipv6.is_some()) && probe.detected_ipv6.is_some();
 
-    decision.ipv4_dc = config.ipv4 && probe.detected_ipv4.is_some();
-    decision.ipv6_dc = config.ipv6.unwrap_or(probe.detected_ipv6.is_some()) && probe.detected_ipv6.is_some();
-
-    decision.ipv4_me = config.ipv4
+    let ipv4_me = config.ipv4
         && probe.detected_ipv4.is_some()
         && (!probe.ipv4_is_bogon || probe.reflected_ipv4.is_some());
 
     let ipv6_enabled = config.ipv6.unwrap_or(probe.detected_ipv6.is_some());
-    decision.ipv6_me = ipv6_enabled
+    let ipv6_me = ipv6_enabled
         && probe.detected_ipv6.is_some()
         && (!probe.ipv6_is_bogon || probe.reflected_ipv6.is_some());
 
-    decision.effective_prefer = match config.prefer {
-        6 if decision.ipv6_me || decision.ipv6_dc => 6,
-        4 if decision.ipv4_me || decision.ipv4_dc => 4,
+    let effective_prefer = match config.prefer {
+        6 if ipv6_me || ipv6_dc => 6,
+        4 if ipv4_me || ipv4_dc => 4,
         6 => {
             warn!("prefer=6 requested but IPv6 unavailable; falling back to IPv4");
             4
@@ -117,10 +249,17 @@ pub fn decide_network_capabilities(config: &NetworkConfig, probe: &NetworkProbe)
         _ => 4,
     };
 
-    let me_families = decision.ipv4_me as u8 + decision.ipv6_me as u8;
-    decision.effective_multipath = config.multipath && me_families >= 2;
+    let me_families = ipv4_me as u8 + ipv6_me as u8;
+    let effective_multipath = config.multipath && me_families >= 2;
 
-    decision
+    NetworkDecision {
+        ipv4_dc,
+        ipv6_dc,
+        ipv4_me,
+        ipv6_me,
+        effective_prefer,
+        effective_multipath,
+    }
 }
 
 fn detect_local_ip_v4() -> Option<Ipv4Addr> {

src/network/stun.rs

@@ -1,9 +1,13 @@
+#![allow(unreachable_code)]
+#![allow(dead_code)]
+
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
 
 use tokio::net::{lookup_host, UdpSocket};
 use tokio::time::{timeout, Duration, sleep};
 
 use crate::error::{ProxyError, Result};
+use crate::network::dns_overrides::{resolve, split_host_port};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum IpFamily {
@@ -37,16 +41,31 @@ pub async fn stun_probe_dual(stun_addr: &str) -> Result<DualStunResult> {
 }
 
 pub async fn stun_probe_family(stun_addr: &str, family: IpFamily) -> Result<Option<StunProbeResult>> {
+    stun_probe_family_with_bind(stun_addr, family, None).await
+}
+
+pub async fn stun_probe_family_with_bind(
+    stun_addr: &str,
+    family: IpFamily,
+    bind_ip: Option<IpAddr>,
+) -> Result<Option<StunProbeResult>> {
     use rand::RngCore;
 
-    let bind_addr = match family {
-        IpFamily::V4 => "0.0.0.0:0",
-        IpFamily::V6 => "[::]:0",
+    let bind_addr = match (family, bind_ip) {
+        (IpFamily::V4, Some(IpAddr::V4(ip))) => SocketAddr::new(IpAddr::V4(ip), 0),
+        (IpFamily::V6, Some(IpAddr::V6(ip))) => SocketAddr::new(IpAddr::V6(ip), 0),
+        (IpFamily::V4, Some(IpAddr::V6(_))) | (IpFamily::V6, Some(IpAddr::V4(_))) => {
+            return Ok(None);
+        }
+        (IpFamily::V4, None) => SocketAddr::new(IpAddr::V4(Ipv4Addr::UNSPECIFIED), 0),
+        (IpFamily::V6, None) => SocketAddr::new(IpAddr::V6(Ipv6Addr::UNSPECIFIED), 0),
     };
 
-    let socket = UdpSocket::bind(bind_addr)
-        .await
-        .map_err(|e| ProxyError::Proxy(format!("STUN bind failed: {e}")))?;
+    let socket = match UdpSocket::bind(bind_addr).await {
+        Ok(socket) => socket,
+        Err(_) if bind_ip.is_some() => return Ok(None),
+        Err(e) => return Err(ProxyError::Proxy(format!("STUN bind failed: {e}"))),
+    };
 
     let target_addr = resolve_stun_addr(stun_addr, family).await?;
     if let Some(addr) = target_addr {
@@ -195,16 +214,21 @@ async fn resolve_stun_addr(stun_addr: &str, family: IpFamily) -> Result<Option<S
         });
     }
 
-    let addrs = lookup_host(stun_addr)
+    if let Some((host, port)) = split_host_port(stun_addr)
+        && let Some(ip) = resolve(&host, port)
+    {
+        let addr = SocketAddr::new(ip, port);
+        return Ok(match (addr.is_ipv4(), family) {
+            (true, IpFamily::V4) | (false, IpFamily::V6) => Some(addr),
+            _ => None,
+        });
+    }
+
+    let mut addrs = lookup_host(stun_addr)
         .await
         .map_err(|e| ProxyError::Proxy(format!("STUN resolve failed: {e}")))?;
 
     let target = addrs
-        .filter(|a| match (a.is_ipv4(), family) {
-            (true, IpFamily::V4) => true,
-            (false, IpFamily::V6) => true,
-            _ => false,
-        })
-        .next();
+        .find(|a| matches!((a.is_ipv4(), family), (true, IpFamily::V4) | (false, IpFamily::V6)));
     Ok(target)
 }

src/protocol/constants.rs

@@ -1,6 +1,10 @@
 //! Protocol constants and datacenter addresses
 
-use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+#![allow(dead_code)]
+
+use std::net::{IpAddr, Ipv4Addr};
+
+use crate::crypto::SecureRandom;
 use std::sync::LazyLock;
 
 // ============= Telegram Datacenters =============
@@ -151,7 +155,32 @@ pub const TLS_RECORD_ALERT: u8 = 0x15;
 /// Maximum TLS record size
 pub const MAX_TLS_RECORD_SIZE: usize = 16384;
 /// Maximum TLS chunk size (with overhead)
-pub const MAX_TLS_CHUNK_SIZE: usize = 16384 + 24;
+/// RFC 8446 §5.2 allows up to 16384 + 256 bytes of ciphertext
+pub const MAX_TLS_CHUNK_SIZE: usize = 16384 + 256;
+
+/// Secure Intermediate payload is expected to be 4-byte aligned.
+pub fn is_valid_secure_payload_len(data_len: usize) -> bool {
+    data_len.is_multiple_of(4)
+}
+
+/// Compute Secure Intermediate payload length from wire length.
+/// Secure mode strips up to 3 random tail bytes by truncating to 4-byte boundary.
+pub fn secure_payload_len_from_wire_len(wire_len: usize) -> Option<usize> {
+    if wire_len < 4 {
+        return None;
+    }
+    Some(wire_len - (wire_len % 4))
+}
+
+/// Generate padding length for Secure Intermediate protocol.
+/// Data must be 4-byte aligned; padding is 1..=3 so total is never divisible by 4.
+pub fn secure_padding_len(data_len: usize, rng: &SecureRandom) -> usize {
+    debug_assert!(
+        is_valid_secure_payload_len(data_len),
+        "Secure payload must be 4-byte aligned, got {data_len}"
+    );
+    rng.range(3) + 1
+}
 
 // ============= Timeouts =============
 
@@ -202,7 +231,6 @@ pub static RESERVED_NONCE_CONTINUES: &[[u8; 4]] = &[
 // ============= RPC Constants (for Middle Proxy) =============
 
 /// RPC Proxy Request
-
 /// RPC Flags (from Erlang mtp_rpc.erl)
 pub const RPC_FLAG_NOT_ENCRYPTED: u32 = 0x2;
 pub const RPC_FLAG_HAS_AD_TAG: u32    = 0x8;
@@ -284,6 +312,10 @@ pub mod rpc_flags {
         pub const FLAG_ABRIDGED: u32      = 0x40000000;
         pub const FLAG_QUICKACK: u32      = 0x80000000;
     }
+
+    pub mod rpc_crypto_flags {
+        pub const USE_CRC32C: u32 = 0x800;
+    }
     
     pub const ME_CONNECT_TIMEOUT_SECS: u64 = 5;
     pub const ME_HANDSHAKE_TIMEOUT_SECS: u64 = 10;
@@ -319,4 +351,43 @@ mod tests {
         assert_eq!(TG_DATACENTERS_V4.len(), 5);
         assert_eq!(TG_DATACENTERS_V6.len(), 5);
     }
-}
+
+    #[test]
+    fn secure_padding_never_produces_aligned_total() {
+        let rng = SecureRandom::new();
+        for data_len in (0..1000).step_by(4) {
+            for _ in 0..100 {
+                let padding = secure_padding_len(data_len, &rng);
+                assert!(
+                    padding <= 3,
+                    "padding out of range: data_len={data_len}, padding={padding}"
+                );
+                assert_ne!(
+                    (data_len + padding) % 4,
+                    0,
+                    "invariant violated: data_len={data_len}, padding={padding}, total={}",
+                    data_len + padding
+                );
+            }
+        }
+    }
+
+    #[test]
+    fn secure_wire_len_roundtrip_for_aligned_payload() {
+        for payload_len in (4..4096).step_by(4) {
+            for padding in 0..=3usize {
+                let wire_len = payload_len + padding;
+                let recovered = secure_payload_len_from_wire_len(wire_len);
+                assert_eq!(recovered, Some(payload_len));
+            }
+        }
+    }
+
+    #[test]
+    fn secure_wire_len_rejects_too_short_frames() {
+        assert_eq!(secure_payload_len_from_wire_len(0), None);
+        assert_eq!(secure_payload_len_from_wire_len(1), None);
+        assert_eq!(secure_payload_len_from_wire_len(2), None);
+        assert_eq!(secure_payload_len_from_wire_len(3), None);
+    }
+}

src/protocol/frame.rs

@@ -1,5 +1,7 @@
 //! MTProto frame types and metadata
 
+#![allow(dead_code)]
+
 use std::collections::HashMap;
 
 /// Extra metadata associated with a frame
@@ -83,7 +85,7 @@ impl FrameMode {
 pub fn validate_message_length(len: usize) -> bool {
     use super::constants::{MIN_MSG_LEN, MAX_MSG_LEN, PADDING_FILLER};
     
-    len >= MIN_MSG_LEN && len <= MAX_MSG_LEN && len % PADDING_FILLER.len() == 0
+    (MIN_MSG_LEN..=MAX_MSG_LEN).contains(&len) && len.is_multiple_of(PADDING_FILLER.len())
 }
 
 #[cfg(test)]

src/protocol/mod.rs

@@ -5,7 +5,11 @@ pub mod frame;
 pub mod obfuscation;
 pub mod tls;
 
+#[allow(unused_imports)]
 pub use constants::*;
+#[allow(unused_imports)]
 pub use frame::*;
+#[allow(unused_imports)]
 pub use obfuscation::*;
+#[allow(unused_imports)]
 pub use tls::*;

src/protocol/obfuscation.rs

@@ -1,8 +1,9 @@
 //! MTProto Obfuscation
 
+#![allow(dead_code)]
+
 use zeroize::Zeroize;
 use crate::crypto::{sha256, AesCtr};
-use crate::error::Result;
 use super::constants::*;
 
 /// Obfuscation parameters from handshake

src/protocol/tls.rs

@@ -4,8 +4,11 @@
 //! for domain fronting. The handshake looks like valid TLS 1.3 but
 //! actually carries MTProto authentication data.
 
+#![allow(dead_code)]
+
 use crate::crypto::{sha256_hmac, SecureRandom};
-use crate::error::{ProxyError, Result};
+#[cfg(test)]
+use crate::error::ProxyError;
 use super::constants::*;
 use std::time::{SystemTime, UNIX_EPOCH};
 use num_bigint::BigUint;
@@ -32,6 +35,7 @@ pub const TIME_SKEW_MAX: i64 = 10 * 60;  // 10 minutes after
 mod extension_type {
     pub const KEY_SHARE: u16 = 0x0033;
     pub const SUPPORTED_VERSIONS: u16 = 0x002b;
+    pub const ALPN: u16 = 0x0010;
 }
 
 /// TLS Cipher Suites
@@ -62,6 +66,7 @@ pub struct TlsValidation {
 // ============= TLS Extension Builder =============
 
 /// Builder for TLS extensions with correct length calculation
+#[derive(Clone)]
 struct TlsExtensionBuilder {
     extensions: Vec<u8>,
 }
@@ -108,6 +113,27 @@ impl TlsExtensionBuilder {
         
         self
     }
+
+    /// Add ALPN extension with a single selected protocol.
+    fn add_alpn(&mut self, proto: &[u8]) -> &mut Self {
+        // Extension type: ALPN (0x0010)
+        self.extensions.extend_from_slice(&extension_type::ALPN.to_be_bytes());
+
+        // ALPN extension format:
+        // extension_data length (2 bytes)
+        //   protocols length (2 bytes)
+        //     protocol name length (1 byte)
+        //     protocol name bytes
+        let proto_len = proto.len() as u8;
+        let list_len: u16 = 1 + proto_len as u16;
+        let ext_len: u16 = 2 + list_len;
+
+        self.extensions.extend_from_slice(&ext_len.to_be_bytes());
+        self.extensions.extend_from_slice(&list_len.to_be_bytes());
+        self.extensions.push(proto_len);
+        self.extensions.extend_from_slice(proto);
+        self
+    }
     
     /// Build final extensions with length prefix
     fn build(self) -> Vec<u8> {
@@ -144,6 +170,8 @@ struct ServerHelloBuilder {
     compression: u8,
     /// Extensions
     extensions: TlsExtensionBuilder,
+    /// Selected ALPN protocol (if any)
+    alpn: Option<Vec<u8>>,
 }
 
 impl ServerHelloBuilder {
@@ -154,6 +182,7 @@ impl ServerHelloBuilder {
             cipher_suite: cipher_suite::TLS_AES_128_GCM_SHA256,
             compression: 0x00,
             extensions: TlsExtensionBuilder::new(),
+            alpn: None,
         }
     }
     
@@ -167,10 +196,19 @@ impl ServerHelloBuilder {
         self.extensions.add_supported_versions(0x0304);
         self
     }
+
+    fn with_alpn(mut self, proto: Option<Vec<u8>>) -> Self {
+        self.alpn = proto;
+        self
+    }
     
     /// Build ServerHello message (without record header)
     fn build_message(&self) -> Vec<u8> {
-        let extensions = self.extensions.extensions.clone();
+        let mut ext_builder = self.extensions.clone();
+        if let Some(ref alpn) = self.alpn {
+            ext_builder.add_alpn(alpn);
+        }
+        let extensions = ext_builder.extensions.clone();
         let extensions_len = extensions.len() as u16;
         
         // Calculate total length
@@ -297,7 +335,7 @@ pub fn validate_tls_handshake(
             // This is a quirk in some clients that use uptime instead of real time
             let is_boot_time = timestamp < 60 * 60 * 24 * 1000; // < ~2.7 years in seconds
             
-            if !is_boot_time && (time_diff < TIME_SKEW_MIN || time_diff > TIME_SKEW_MAX) {
+            if !is_boot_time && !(TIME_SKEW_MIN..=TIME_SKEW_MAX).contains(&time_diff) {
                 continue;
             }
         }
@@ -350,16 +388,19 @@ pub fn build_server_hello(
     session_id: &[u8],
     fake_cert_len: usize,
     rng: &SecureRandom,
+    alpn: Option<Vec<u8>>,
+    new_session_tickets: u8,
 ) -> Vec<u8> {
     const MIN_APP_DATA: usize = 64;
     const MAX_APP_DATA: usize = 16640; // RFC 8446 §5.2 upper bound
-    let fake_cert_len = fake_cert_len.max(MIN_APP_DATA).min(MAX_APP_DATA);
+    let fake_cert_len = fake_cert_len.clamp(MIN_APP_DATA, MAX_APP_DATA);
     let x25519_key = gen_fake_x25519_key(rng);
     
     // Build ServerHello
     let server_hello = ServerHelloBuilder::new(session_id.to_vec())
         .with_x25519_key(&x25519_key)
         .with_tls13_version()
+        .with_alpn(alpn)
         .build_record();
     
     // Build Change Cipher Spec record
@@ -376,21 +417,35 @@ pub fn build_server_hello(
     app_data_record.push(TLS_RECORD_APPLICATION);
     app_data_record.extend_from_slice(&TLS_VERSION);
     app_data_record.extend_from_slice(&(fake_cert_len as u16).to_be_bytes());
-    if fake_cert_len > 17 {
-        app_data_record.extend_from_slice(&fake_cert[..fake_cert_len - 17]);
-        app_data_record.push(0x16); // inner content type marker
-        app_data_record.extend_from_slice(&rng.bytes(16)); // AEAD-like tag mimic
-    } else {
-        app_data_record.extend_from_slice(&fake_cert);
-    }
+    // Fill ApplicationData with fully random bytes of desired length to avoid
+    // deterministic DPI fingerprints (fixed inner content type markers).
+    app_data_record.extend_from_slice(&fake_cert);
     
+    // Build optional NewSessionTicket records (TLS 1.3 handshake messages are encrypted;
+    // here we mimic with opaque ApplicationData records of plausible size).
+    let mut tickets = Vec::new();
+    if new_session_tickets > 0 {
+        for _ in 0..new_session_tickets {
+            let ticket_len: usize = rng.range(48) + 48; // 48-95 bytes
+            let mut record = Vec::with_capacity(5 + ticket_len);
+            record.push(TLS_RECORD_APPLICATION);
+            record.extend_from_slice(&TLS_VERSION);
+            record.extend_from_slice(&(ticket_len as u16).to_be_bytes());
+            record.extend_from_slice(&rng.bytes(ticket_len));
+            tickets.push(record);
+        }
+    }
+
     // Combine all records
     let mut response = Vec::with_capacity(
-        server_hello.len() + change_cipher_spec.len() + app_data_record.len()
+        server_hello.len() + change_cipher_spec.len() + app_data_record.len() + tickets.iter().map(|r| r.len()).sum::<usize>()
     );
     response.extend_from_slice(&server_hello);
     response.extend_from_slice(&change_cipher_spec);
     response.extend_from_slice(&app_data_record);
+    for t in &tickets {
+        response.extend_from_slice(t);
+    }
     
     // Compute HMAC for the response
     let mut hmac_input = Vec::with_capacity(TLS_DIGEST_LEN + response.len());
@@ -470,10 +525,10 @@ pub fn extract_sni_from_client_hello(handshake: &[u8]) -> Option<String> {
                 if sn_pos + name_len > sn_end {
                     break;
                 }
-                if name_type == 0 && name_len > 0 {
-                    if let Ok(host) = std::str::from_utf8(&handshake[sn_pos..sn_pos + name_len]) {
-                        return Some(host.to_string());
-                    }
+                if name_type == 0 && name_len > 0
+                    && let Ok(host) = std::str::from_utf8(&handshake[sn_pos..sn_pos + name_len])
+                {
+                    return Some(host.to_string());
                 }
                 sn_pos += name_len;
             }
@@ -484,85 +539,53 @@ pub fn extract_sni_from_client_hello(handshake: &[u8]) -> Option<String> {
     None
 }
 
-/// Extract ALPN protocol list from TLS ClientHello.
-pub fn extract_alpn_from_client_hello(handshake: &[u8]) -> Option<Vec<String>> {
-    if handshake.len() < 43 || handshake[0] != TLS_RECORD_HANDSHAKE {
-        return None;
-    }
-
+/// Extract ALPN protocol list from ClientHello, return in offered order.
+pub fn extract_alpn_from_client_hello(handshake: &[u8]) -> Vec<Vec<u8>> {
     let mut pos = 5; // after record header
-    if handshake.get(pos).copied()? != 0x01 {
-        return None; // not ClientHello
+    if handshake.get(pos) != Some(&0x01) {
+        return Vec::new();
     }
-
-    // Handshake length bytes
-    pos += 4; // type + len (3)
-
-    // version (2) + random (32)
-    pos += 2 + 32;
-    if pos + 1 > handshake.len() {
-        return None;
-    }
-
-    let session_id_len = *handshake.get(pos)? as usize;
+    pos += 4; // type + len
+    pos += 2 + 32; // version + random
+    if pos >= handshake.len() { return Vec::new(); }
+    let session_id_len = *handshake.get(pos).unwrap_or(&0) as usize;
     pos += 1 + session_id_len;
-    if pos + 2 > handshake.len() {
-        return None;
-    }
-
-    let cipher_suites_len = u16::from_be_bytes([handshake[pos], handshake[pos + 1]]) as usize;
-    pos += 2 + cipher_suites_len;
-    if pos + 1 > handshake.len() {
-        return None;
-    }
-
-    let comp_len = *handshake.get(pos)? as usize;
+    if pos + 2 > handshake.len() { return Vec::new(); }
+    let cipher_len = u16::from_be_bytes([handshake[pos], handshake[pos+1]]) as usize;
+    pos += 2 + cipher_len;
+    if pos >= handshake.len() { return Vec::new(); }
+    let comp_len = *handshake.get(pos).unwrap_or(&0) as usize;
     pos += 1 + comp_len;
-    if pos + 2 > handshake.len() {
-        return None;
-    }
-
-    let ext_len = u16::from_be_bytes([handshake[pos], handshake[pos + 1]]) as usize;
+    if pos + 2 > handshake.len() { return Vec::new(); }
+    let ext_len = u16::from_be_bytes([handshake[pos], handshake[pos+1]]) as usize;
     pos += 2;
     let ext_end = pos + ext_len;
-    if ext_end > handshake.len() {
-        return None;
-    }
-
+    if ext_end > handshake.len() { return Vec::new(); }
+    let mut out = Vec::new();
     while pos + 4 <= ext_end {
-        let etype = u16::from_be_bytes([handshake[pos], handshake[pos + 1]]);
-        let elen = u16::from_be_bytes([handshake[pos + 2], handshake[pos + 3]]) as usize;
+        let etype = u16::from_be_bytes([handshake[pos], handshake[pos+1]]);
+        let elen = u16::from_be_bytes([handshake[pos+2], handshake[pos+3]]) as usize;
         pos += 4;
-        if pos + elen > ext_end {
+        if pos + elen > ext_end { break; }
+        if etype == extension_type::ALPN && elen >= 3 {
+            let list_len = u16::from_be_bytes([handshake[pos], handshake[pos+1]]) as usize;
+            let mut lp = pos + 2;
+            let list_end = (pos + 2).saturating_add(list_len).min(pos + elen);
+            while lp < list_end {
+                let plen = handshake[lp] as usize;
+                lp += 1;
+                if lp + plen > list_end { break; }
+                out.push(handshake[lp..lp+plen].to_vec());
+                lp += plen;
+            }
             break;
         }
-
-        if etype == 0x0010 && elen >= 3 {
-            // ALPN
-            let list_len = u16::from_be_bytes([handshake[pos], handshake[pos + 1]]) as usize;
-            let mut alpn_pos = pos + 2;
-            let list_end = std::cmp::min(alpn_pos + list_len, pos + elen);
-            let mut protocols = Vec::new();
-            while alpn_pos < list_end {
-                let proto_len = *handshake.get(alpn_pos)? as usize;
-                alpn_pos += 1;
-                if alpn_pos + proto_len > list_end {
-                    break;
-                }
-                if let Ok(p) = std::str::from_utf8(&handshake[alpn_pos..alpn_pos + proto_len]) {
-                    protocols.push(p.to_string());
-                }
-                alpn_pos += proto_len;
-            }
-            return Some(protocols);
-        }
-
         pos += elen;
     }
-
-    None
+    out
 }
 
+
 /// Check if bytes look like a TLS ClientHello
 pub fn is_tls_handshake(first_bytes: &[u8]) -> bool {
     if first_bytes.len() < 3 {
@@ -593,7 +616,7 @@ pub fn parse_tls_record_header(header: &[u8; 5]) -> Option<(u8, u16)> {
 ///
 /// This is useful for testing that our ServerHello is well-formed.
 #[cfg(test)]
-fn validate_server_hello_structure(data: &[u8]) -> Result<()> {
+fn validate_server_hello_structure(data: &[u8]) -> Result<(), ProxyError> {
     if data.len() < 5 {
         return Err(ProxyError::InvalidTlsRecord {
             record_type: 0,
@@ -741,7 +764,7 @@ mod tests {
         let session_id = vec![0xAA; 32];
         
         let rng = SecureRandom::new();
-        let response = build_server_hello(secret, &client_digest, &session_id, 2048, &rng);
+        let response = build_server_hello(secret, &client_digest, &session_id, 2048, &rng, None, 0);
         
         // Should have at least 3 records
         assert!(response.len() > 100);
@@ -774,8 +797,8 @@ mod tests {
         let session_id = vec![0xAA; 32];
         
         let rng = SecureRandom::new();
-        let response1 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng);
-        let response2 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng);
+        let response1 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng, None, 0);
+        let response2 = build_server_hello(secret, &client_digest, &session_id, 1024, &rng, None, 0);
         
         // Digest position should have non-zero data
         let digest1 = &response1[TLS_DIGEST_POS..TLS_DIGEST_POS + TLS_DIGEST_LEN];
@@ -904,8 +927,12 @@ mod tests {
         alpn_data.push(2);
         alpn_data.extend_from_slice(b"h2");
         let ch = build_client_hello_with_exts(vec![(0x0010, alpn_data)], "alpn.test");
-        let alpn = extract_alpn_from_client_hello(&ch).unwrap();
-        assert_eq!(alpn, vec!["h2"]);
+        let alpn = extract_alpn_from_client_hello(&ch);
+        let alpn_str: Vec<String> = alpn
+            .iter()
+            .map(|p| std::str::from_utf8(p).unwrap().to_string())
+            .collect();
+        assert_eq!(alpn_str, vec!["h2"]);
     }
 
     #[test]
@@ -920,7 +947,11 @@ mod tests {
         alpn_data.push(2);
         alpn_data.extend_from_slice(b"h3");
         let ch = build_client_hello_with_exts(vec![(0x0010, alpn_data)], "alpn.test");
-        let alpn = extract_alpn_from_client_hello(&ch).unwrap();
-        assert_eq!(alpn, vec!["h2", "spdy", "h3"]);
+        let alpn = extract_alpn_from_client_hello(&ch);
+        let alpn_str: Vec<String> = alpn
+            .iter()
+            .map(|p| std::str::from_utf8(p).unwrap().to_string())
+            .collect();
+        assert_eq!(alpn_str, vec!["h2", "spdy", "h3"]);
     }
 }

src/proxy/client.rs

@@ -1,7 +1,7 @@
 //! Client Handler
 
 use std::future::Future;
-use std::net::SocketAddr;
+use std::net::{IpAddr, SocketAddr};
 use std::pin::Pin;
 use std::sync::Arc;
 use std::time::Duration;
@@ -27,6 +27,7 @@ use crate::error::{HandshakeResult, ProxyError, Result};
 use crate::ip_tracker::UserIpTracker;
 use crate::protocol::constants::*;
 use crate::protocol::tls;
+use crate::stats::beobachten::BeobachtenStore;
 use crate::stats::{ReplayChecker, Stats};
 use crate::stream::{BufferPool, CryptoReader, CryptoWriter};
 use crate::transport::middle_proxy::MePool;
@@ -39,6 +40,36 @@ use crate::proxy::handshake::{HandshakeSuccess, handle_mtproto_handshake, handle
 use crate::proxy::masking::handle_bad_client;
 use crate::proxy::middle_relay::handle_via_middle_proxy;
 
+fn beobachten_ttl(config: &ProxyConfig) -> Duration {
+    Duration::from_secs(config.general.beobachten_minutes.saturating_mul(60))
+}
+
+fn record_beobachten_class(
+    beobachten: &BeobachtenStore,
+    config: &ProxyConfig,
+    peer_ip: IpAddr,
+    class: &str,
+) {
+    if !config.general.beobachten {
+        return;
+    }
+    beobachten.record(class, peer_ip, beobachten_ttl(config));
+}
+
+fn record_handshake_failure_class(
+    beobachten: &BeobachtenStore,
+    config: &ProxyConfig,
+    peer_ip: IpAddr,
+    error: &ProxyError,
+) {
+    let class = if error.to_string().contains("expected 64 bytes, got 0") {
+        "expected_64_got_0"
+    } else {
+        "other"
+    };
+    record_beobachten_class(beobachten, config, peer_ip, class);
+}
+
 pub async fn handle_client_stream<S>(
     mut stream: S,
     peer: SocketAddr,
@@ -51,6 +82,7 @@ pub async fn handle_client_stream<S>(
     me_pool: Option<Arc<MePool>>,
     tls_cache: Option<Arc<TlsFrontCache>>,
     ip_tracker: Arc<UserIpTracker>,
+    beobachten: Arc<BeobachtenStore>,
     proxy_protocol_enabled: bool,
 ) -> Result<()>
 where
@@ -59,9 +91,17 @@ where
     stats.increment_connects_all();
     let mut real_peer = normalize_ip(peer);
 
+    // For non-TCP streams, use a synthetic local address; may be overridden by PROXY protocol dst
+    let mut local_addr: SocketAddr = format!("0.0.0.0:{}", config.server.port)
+        .parse()
+        .unwrap_or_else(|_| "0.0.0.0:443".parse().unwrap());
+
     if proxy_protocol_enabled {
-        match parse_proxy_protocol(&mut stream, peer).await {
-            Ok(info) => {
+        let proxy_header_timeout = Duration::from_millis(
+            config.server.proxy_protocol_header_timeout_ms.max(1),
+        );
+        match timeout(proxy_header_timeout, parse_proxy_protocol(&mut stream, peer)).await {
+            Ok(Ok(info)) => {
                 debug!(
                     peer = %peer,
                     client = %info.src_addr,
@@ -69,12 +109,22 @@ where
                     "PROXY protocol header parsed"
                 );
                 real_peer = normalize_ip(info.src_addr);
+                if let Some(dst) = info.dst_addr {
+                    local_addr = dst;
+                }
             }
-            Err(e) => {
+            Ok(Err(e)) => {
                 stats.increment_connects_bad();
                 warn!(peer = %peer, error = %e, "Invalid PROXY protocol header");
+                record_beobachten_class(&beobachten, &config, peer.ip(), "other");
                 return Err(e);
             }
+            Err(_) => {
+                stats.increment_connects_bad();
+                warn!(peer = %peer, timeout_ms = proxy_header_timeout.as_millis(), "PROXY protocol header timeout");
+                record_beobachten_class(&beobachten, &config, peer.ip(), "other");
+                return Err(ProxyError::InvalidProxyProtocol);
+            }
         }
     }
 
@@ -82,11 +132,9 @@ where
 
     let handshake_timeout = Duration::from_secs(config.timeouts.client_handshake);
     let stats_for_timeout = stats.clone();
-
-    // For non-TCP streams, use a synthetic local address
-    let local_addr: SocketAddr = format!("0.0.0.0:{}", config.server.port)
-        .parse()
-        .unwrap_or_else(|_| "0.0.0.0:443".parse().unwrap());
+    let config_for_timeout = config.clone();
+    let beobachten_for_timeout = beobachten.clone();
+    let peer_for_timeout = real_peer.ip();
 
     // Phase 1: handshake (with timeout)
     let outcome = match timeout(handshake_timeout, async {
@@ -103,7 +151,16 @@ where
                 debug!(peer = %real_peer, tls_len = tls_len, "TLS handshake too short");
                 stats.increment_connects_bad();
                 let (reader, writer) = tokio::io::split(stream);
-                handle_bad_client(reader, writer, &first_bytes, &config).await;
+                handle_bad_client(
+                    reader,
+                    writer,
+                    &first_bytes,
+                    real_peer,
+                    local_addr,
+                    &config,
+                    &beobachten,
+                )
+                .await;
                 return Ok(HandshakeOutcome::Handled);
             }
 
@@ -113,14 +170,23 @@ where
 
             let (read_half, write_half) = tokio::io::split(stream);
 
-            let (mut tls_reader, tls_writer, _tls_user) = match handle_tls_handshake(
+            let (mut tls_reader, tls_writer, tls_user) = match handle_tls_handshake(
                 &handshake, read_half, write_half, real_peer,
                 &config, &replay_checker, &rng, tls_cache.clone(),
             ).await {
                 HandshakeResult::Success(result) => result,
                 HandshakeResult::BadClient { reader, writer } => {
                     stats.increment_connects_bad();
-                    handle_bad_client(reader, writer, &handshake, &config).await;
+                    handle_bad_client(
+                        reader,
+                        writer,
+                        &handshake,
+                        real_peer,
+                        local_addr,
+                        &config,
+                        &beobachten,
+                    )
+                    .await;
                     return Ok(HandshakeOutcome::Handled);
                 }
                 HandshakeResult::Error(e) => return Err(e),
@@ -133,7 +199,7 @@ where
 
             let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
                 &mtproto_handshake, tls_reader, tls_writer, real_peer,
-                &config, &replay_checker, true,
+                &config, &replay_checker, true, Some(tls_user.as_str()),
             ).await {
                 HandshakeResult::Success(result) => result,
                 HandshakeResult::BadClient { reader: _, writer: _ } => {
@@ -156,7 +222,16 @@ where
                 debug!(peer = %real_peer, "Non-TLS modes disabled");
                 stats.increment_connects_bad();
                 let (reader, writer) = tokio::io::split(stream);
-                handle_bad_client(reader, writer, &first_bytes, &config).await;
+                handle_bad_client(
+                    reader,
+                    writer,
+                    &first_bytes,
+                    real_peer,
+                    local_addr,
+                    &config,
+                    &beobachten,
+                )
+                .await;
                 return Ok(HandshakeOutcome::Handled);
             }
 
@@ -168,12 +243,21 @@ where
 
             let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
                 &handshake, read_half, write_half, real_peer,
-                &config, &replay_checker, false,
+                &config, &replay_checker, false, None,
             ).await {
                 HandshakeResult::Success(result) => result,
                 HandshakeResult::BadClient { reader, writer } => {
                     stats.increment_connects_bad();
-                    handle_bad_client(reader, writer, &handshake, &config).await;
+                    handle_bad_client(
+                        reader,
+                        writer,
+                        &handshake,
+                        real_peer,
+                        local_addr,
+                        &config,
+                        &beobachten,
+                    )
+                    .await;
                     return Ok(HandshakeOutcome::Handled);
                 }
                 HandshakeResult::Error(e) => return Err(e),
@@ -200,11 +284,23 @@ where
         Ok(Ok(outcome)) => outcome,
         Ok(Err(e)) => {
             debug!(peer = %peer, error = %e, "Handshake failed");
+            record_handshake_failure_class(
+                &beobachten_for_timeout,
+                &config_for_timeout,
+                peer_for_timeout,
+                &e,
+            );
             return Err(e);
         }
         Err(_) => {
             stats_for_timeout.increment_handshake_timeouts();
             debug!(peer = %peer, "Handshake timeout");
+            record_beobachten_class(
+                &beobachten_for_timeout,
+                &config_for_timeout,
+                peer_for_timeout,
+                "other",
+            );
             return Err(ProxyError::TgHandshakeTimeout);
         }
     };
@@ -230,6 +326,7 @@ pub struct RunningClientHandler {
     me_pool: Option<Arc<MePool>>,
     tls_cache: Option<Arc<TlsFrontCache>>,
     ip_tracker: Arc<UserIpTracker>,
+    beobachten: Arc<BeobachtenStore>,
     proxy_protocol_enabled: bool,
 }
 
@@ -246,6 +343,7 @@ impl ClientHandler {
         me_pool: Option<Arc<MePool>>,
         tls_cache: Option<Arc<TlsFrontCache>>,
         ip_tracker: Arc<UserIpTracker>,
+        beobachten: Arc<BeobachtenStore>,
         proxy_protocol_enabled: bool,
     ) -> RunningClientHandler {
         RunningClientHandler {
@@ -260,6 +358,7 @@ impl ClientHandler {
             me_pool,
             tls_cache,
             ip_tracker,
+            beobachten,
             proxy_protocol_enabled,
         }
     }
@@ -271,7 +370,7 @@ impl RunningClientHandler {
 
         self.peer = normalize_ip(self.peer);
         let peer = self.peer;
-        let ip_tracker = self.ip_tracker.clone();
+        let _ip_tracker = self.ip_tracker.clone();
         debug!(peer = %peer, "New connection");
 
         if let Err(e) = configure_client_socket(
@@ -284,17 +383,32 @@ impl RunningClientHandler {
 
         let handshake_timeout = Duration::from_secs(self.config.timeouts.client_handshake);
         let stats = self.stats.clone();
+        let config_for_timeout = self.config.clone();
+        let beobachten_for_timeout = self.beobachten.clone();
+        let peer_for_timeout = peer.ip();
 
         // Phase 1: handshake (with timeout)
         let outcome = match timeout(handshake_timeout, self.do_handshake()).await {
             Ok(Ok(outcome)) => outcome,
             Ok(Err(e)) => {
                 debug!(peer = %peer, error = %e, "Handshake failed");
+                record_handshake_failure_class(
+                    &beobachten_for_timeout,
+                    &config_for_timeout,
+                    peer_for_timeout,
+                    &e,
+                );
                 return Err(e);
             }
             Err(_) => {
                 stats.increment_handshake_timeouts();
                 debug!(peer = %peer, "Handshake timeout");
+                record_beobachten_class(
+                    &beobachten_for_timeout,
+                    &config_for_timeout,
+                    peer_for_timeout,
+                    "other",
+                );
                 return Err(ProxyError::TgHandshakeTimeout);
             }
         };
@@ -307,9 +421,19 @@ impl RunningClientHandler {
     }
 
     async fn do_handshake(mut self) -> Result<HandshakeOutcome> {
+        let mut local_addr = self.stream.local_addr().map_err(ProxyError::Io)?;
+
         if self.proxy_protocol_enabled {
-            match parse_proxy_protocol(&mut self.stream, self.peer).await {
-                Ok(info) => {
+            let proxy_header_timeout = Duration::from_millis(
+                self.config.server.proxy_protocol_header_timeout_ms.max(1),
+            );
+            match timeout(
+                proxy_header_timeout,
+                parse_proxy_protocol(&mut self.stream, self.peer),
+            )
+            .await
+            {
+                Ok(Ok(info)) => {
                     debug!(
                         peer = %self.peer,
                         client = %info.src_addr,
@@ -317,12 +441,36 @@ impl RunningClientHandler {
                         "PROXY protocol header parsed"
                     );
                     self.peer = normalize_ip(info.src_addr);
+                    if let Some(dst) = info.dst_addr {
+                        local_addr = dst;
+                    }
                 }
-                Err(e) => {
+                Ok(Err(e)) => {
                     self.stats.increment_connects_bad();
                     warn!(peer = %self.peer, error = %e, "Invalid PROXY protocol header");
+                    record_beobachten_class(
+                        &self.beobachten,
+                        &self.config,
+                        self.peer.ip(),
+                        "other",
+                    );
                     return Err(e);
                 }
+                Err(_) => {
+                    self.stats.increment_connects_bad();
+                    warn!(
+                        peer = %self.peer,
+                        timeout_ms = proxy_header_timeout.as_millis(),
+                        "PROXY protocol header timeout"
+                    );
+                    record_beobachten_class(
+                        &self.beobachten,
+                        &self.config,
+                        self.peer.ip(),
+                        "other",
+                    );
+                    return Err(ProxyError::InvalidProxyProtocol);
+                }
             }
         }
 
@@ -331,20 +479,20 @@ impl RunningClientHandler {
 
         let is_tls = tls::is_tls_handshake(&first_bytes[..3]);
         let peer = self.peer;
-        let ip_tracker = self.ip_tracker.clone();
+        let _ip_tracker = self.ip_tracker.clone();
 
         debug!(peer = %peer, is_tls = is_tls, "Handshake type detected");
 
         if is_tls {
-            self.handle_tls_client(first_bytes).await
+            self.handle_tls_client(first_bytes, local_addr).await
         } else {
-            self.handle_direct_client(first_bytes).await
+            self.handle_direct_client(first_bytes, local_addr).await
         }
     }
 
-    async fn handle_tls_client(mut self, first_bytes: [u8; 5]) -> Result<HandshakeOutcome> {
+    async fn handle_tls_client(mut self, first_bytes: [u8; 5], local_addr: SocketAddr) -> Result<HandshakeOutcome> {
         let peer = self.peer;
-        let ip_tracker = self.ip_tracker.clone();
+        let _ip_tracker = self.ip_tracker.clone();
 
         let tls_len = u16::from_be_bytes([first_bytes[3], first_bytes[4]]) as usize;
 
@@ -354,7 +502,16 @@ impl RunningClientHandler {
             debug!(peer = %peer, tls_len = tls_len, "TLS handshake too short");
             self.stats.increment_connects_bad();
             let (reader, writer) = self.stream.into_split();
-            handle_bad_client(reader, writer, &first_bytes, &self.config).await;
+            handle_bad_client(
+                reader,
+                writer,
+                &first_bytes,
+                peer,
+                local_addr,
+                &self.config,
+                &self.beobachten,
+            )
+            .await;
             return Ok(HandshakeOutcome::Handled);
         }
 
@@ -367,10 +524,9 @@ impl RunningClientHandler {
         let stats = self.stats.clone();
         let buffer_pool = self.buffer_pool.clone();
 
-        let local_addr = self.stream.local_addr().map_err(ProxyError::Io)?;
         let (read_half, write_half) = self.stream.into_split();
 
-        let (mut tls_reader, tls_writer, _tls_user) = match handle_tls_handshake(
+        let (mut tls_reader, tls_writer, tls_user) = match handle_tls_handshake(
             &handshake,
             read_half,
             write_half,
@@ -385,7 +541,16 @@ impl RunningClientHandler {
             HandshakeResult::Success(result) => result,
             HandshakeResult::BadClient { reader, writer } => {
                 stats.increment_connects_bad();
-                handle_bad_client(reader, writer, &handshake, &config).await;
+                handle_bad_client(
+                    reader,
+                    writer,
+                    &handshake,
+                    peer,
+                    local_addr,
+                    &config,
+                    &self.beobachten,
+                )
+                .await;
                 return Ok(HandshakeOutcome::Handled);
             }
             HandshakeResult::Error(e) => return Err(e),
@@ -405,6 +570,7 @@ impl RunningClientHandler {
             &config,
             &replay_checker,
             true,
+            Some(tls_user.as_str()),
         )
         .await
         {
@@ -438,15 +604,24 @@ impl RunningClientHandler {
         )))
     }
 
-    async fn handle_direct_client(mut self, first_bytes: [u8; 5]) -> Result<HandshakeOutcome> {
+    async fn handle_direct_client(mut self, first_bytes: [u8; 5], local_addr: SocketAddr) -> Result<HandshakeOutcome> {
         let peer = self.peer;
-        let ip_tracker = self.ip_tracker.clone();
+        let _ip_tracker = self.ip_tracker.clone();
 
         if !self.config.general.modes.classic && !self.config.general.modes.secure {
             debug!(peer = %peer, "Non-TLS modes disabled");
             self.stats.increment_connects_bad();
             let (reader, writer) = self.stream.into_split();
-            handle_bad_client(reader, writer, &first_bytes, &self.config).await;
+            handle_bad_client(
+                reader,
+                writer,
+                &first_bytes,
+                peer,
+                local_addr,
+                &self.config,
+                &self.beobachten,
+            )
+            .await;
             return Ok(HandshakeOutcome::Handled);
         }
 
@@ -459,7 +634,6 @@ impl RunningClientHandler {
         let stats = self.stats.clone();
         let buffer_pool = self.buffer_pool.clone();
 
-        let local_addr = self.stream.local_addr().map_err(ProxyError::Io)?;
         let (read_half, write_half) = self.stream.into_split();
 
         let (crypto_reader, crypto_writer, success) = match handle_mtproto_handshake(
@@ -470,13 +644,23 @@ impl RunningClientHandler {
             &config,
             &replay_checker,
             false,
+            None,
         )
         .await
         {
             HandshakeResult::Success(result) => result,
             HandshakeResult::BadClient { reader, writer } => {
                 stats.increment_connects_bad();
-                handle_bad_client(reader, writer, &handshake, &config).await;
+                handle_bad_client(
+                    reader,
+                    writer,
+                    &handshake,
+                    peer,
+                    local_addr,
+                    &config,
+                    &self.beobachten,
+                )
+                .await;
                 return Ok(HandshakeOutcome::Handled);
             }
             HandshakeResult::Error(e) => return Err(e),
@@ -522,42 +706,16 @@ impl RunningClientHandler {
         R: AsyncRead + Unpin + Send + 'static,
         W: AsyncWrite + Unpin + Send + 'static,
     {
-        let user = &success.user;
+        let user = success.user.clone();
 
-        if let Err(e) = Self::check_user_limits_static(user, &config, &stats, peer_addr, &ip_tracker).await {
+        if let Err(e) = Self::check_user_limits_static(&user, &config, &stats, peer_addr, &ip_tracker).await {
             warn!(user = %user, error = %e, "User limit exceeded");
             return Err(e);
         }
 
-        // IP Cleanup Guard: автоматически удаляет IP при выходе из scope
-        struct IpCleanupGuard {
-            tracker: Arc<UserIpTracker>,
-            user: String,
-            ip: std::net::IpAddr,
-        }
-        
-        impl Drop for IpCleanupGuard {
-            fn drop(&mut self) {
-                let tracker = self.tracker.clone();
-                let user = self.user.clone();
-                let ip = self.ip;
-                tokio::spawn(async move {
-                    tracker.remove_ip(&user, ip).await;
-                    debug!(user = %user, ip = %ip, "IP cleaned up on disconnect");
-                });
-            }
-        }
-        
-        let _cleanup = IpCleanupGuard {
-            tracker: ip_tracker,
-            user: user.clone(),
-            ip: peer_addr.ip(),
-        };
-
-        // Decide: middle proxy or direct
-        if config.general.use_middle_proxy {
+        let relay_result = if config.general.use_middle_proxy {
             if let Some(ref pool) = me_pool {
-                return handle_via_middle_proxy(
+                handle_via_middle_proxy(
                     client_reader,
                     client_writer,
                     success,
@@ -568,23 +726,38 @@ impl RunningClientHandler {
                     local_addr,
                     rng,
                 )
-                .await;
+                .await
+            } else {
+                warn!("use_middle_proxy=true but MePool not initialized, falling back to direct");
+                handle_via_direct(
+                    client_reader,
+                    client_writer,
+                    success,
+                    upstream_manager,
+                    stats,
+                    config,
+                    buffer_pool,
+                    rng,
+                )
+                .await
             }
-            warn!("use_middle_proxy=true but MePool not initialized, falling back to direct");
-        }
+        } else {
+            // Direct mode (original behavior)
+            handle_via_direct(
+                client_reader,
+                client_writer,
+                success,
+                upstream_manager,
+                stats,
+                config,
+                buffer_pool,
+                rng,
+            )
+            .await
+        };
 
-        // Direct mode (original behavior)
-        handle_via_direct(
-            client_reader,
-            client_writer,
-            success,
-            upstream_manager,
-            stats,
-            config,
-            buffer_pool,
-            rng,
-        )
-        .await
+        ip_tracker.remove_ip(&user, peer_addr.ip()).await;
+        relay_result
     }
 
     async fn check_user_limits_static(
@@ -594,41 +767,55 @@ impl RunningClientHandler {
         peer_addr: SocketAddr,
         ip_tracker: &UserIpTracker,
     ) -> Result<()> {
-        if let Some(expiration) = config.access.user_expirations.get(user) {
-            if chrono::Utc::now() > *expiration {
-                return Err(ProxyError::UserExpired {
-                    user: user.to_string(),
-                });
-            }
-        }
-
-        // IP limit check
-        if let Err(reason) = ip_tracker.check_and_add(user, peer_addr.ip()).await {
-            warn!(
-                user = %user, 
-                ip = %peer_addr.ip(),
-                reason = %reason,
-                "IP limit exceeded"
-            );
-            return Err(ProxyError::ConnectionLimitExceeded {
+        if let Some(expiration) = config.access.user_expirations.get(user)
+            && chrono::Utc::now() > *expiration
+        {
+            return Err(ProxyError::UserExpired {
                 user: user.to_string(),
             });
         }
 
-        if let Some(limit) = config.access.user_max_tcp_conns.get(user) {
-            if stats.get_user_curr_connects(user) >= *limit as u64 {
+        let mut ip_reserved = false;
+        // IP limit check
+        match ip_tracker.check_and_add(user, peer_addr.ip()).await {
+            Ok(()) => {
+                ip_reserved = true;
+            }
+            Err(reason) => {
+                warn!(
+                    user = %user,
+                    ip = %peer_addr.ip(),
+                    reason = %reason,
+                    "IP limit exceeded"
+                );
                 return Err(ProxyError::ConnectionLimitExceeded {
                     user: user.to_string(),
                 });
             }
         }
 
-        if let Some(quota) = config.access.user_data_quota.get(user) {
-            if stats.get_user_total_octets(user) >= *quota {
-                return Err(ProxyError::DataQuotaExceeded {
-                    user: user.to_string(),
-                });
+        if let Some(limit) = config.access.user_max_tcp_conns.get(user)
+            && stats.get_user_curr_connects(user) >= *limit as u64
+        {
+            if ip_reserved {
+                ip_tracker.remove_ip(user, peer_addr.ip()).await;
+                stats.increment_ip_reservation_rollback_tcp_limit_total();
             }
+            return Err(ProxyError::ConnectionLimitExceeded {
+                user: user.to_string(),
+            });
+        }
+
+        if let Some(quota) = config.access.user_data_quota.get(user)
+            && stats.get_user_total_octets(user) >= *quota
+        {
+            if ip_reserved {
+                ip_tracker.remove_ip(user, peer_addr.ip()).await;
+                stats.increment_ip_reservation_rollback_quota_limit_total();
+            }
+            return Err(ProxyError::DataQuotaExceeded {
+                user: user.to_string(),
+            });
         }
 
         Ok(())

src/proxy/direct_relay.rs

@@ -34,7 +34,7 @@ where
     let user = &success.user;
     let dc_addr = get_dc_addr_static(success.dc_idx, &config)?;
 
-    info!(
+    debug!(
         user = %user,
         peer = %success.peer,
         dc = success.dc_idx,
@@ -57,6 +57,7 @@ where
 
     stats.increment_user_connects(user);
     stats.increment_user_curr_connects(user);
+    stats.increment_current_connections_direct();
 
     let relay_result = relay_bidirectional(
         client_reader,
@@ -69,6 +70,7 @@ where
     )
     .await;
 
+    stats.decrement_current_connections_direct();
     stats.decrement_user_curr_connects(user);
 
     match &relay_result {
@@ -118,10 +120,16 @@ fn get_dc_addr_static(dc_idx: i16, config: &ProxyConfig) -> Result<SocketAddr> {
     // Unknown DC requested by client without override: log and fall back.
     if !config.dc_overrides.contains_key(&dc_key) {
         warn!(dc_idx = dc_idx, "Requested non-standard DC with no override; falling back to default cluster");
-        if let Some(path) = &config.general.unknown_dc_log_path {
-            if let Ok(mut file) = OpenOptions::new().create(true).append(true).open(path) {
-                let _ = writeln!(file, "dc_idx={dc_idx}");
-            }
+        if config.general.unknown_dc_file_log_enabled
+            && let Some(path) = &config.general.unknown_dc_log_path
+            && let Ok(handle) = tokio::runtime::Handle::try_current()
+        {
+            let path = path.clone();
+            handle.spawn_blocking(move || {
+                if let Ok(mut file) = OpenOptions::new().create(true).append(true).open(path) {
+                    let _ = writeln!(file, "dc_idx={dc_idx}");
+                }
+            });
         }
     }
 
@@ -178,8 +186,9 @@ async fn do_tg_handshake_static(
 
     let (read_half, write_half) = stream.into_split();
 
+    let max_pending = config.general.crypto_pending_buffer;
     Ok((
         CryptoReader::new(read_half, tg_decryptor),
-        CryptoWriter::new(write_half, tg_encryptor),
+        CryptoWriter::new(write_half, tg_encryptor, max_pending),
     ))
 }

src/proxy/handshake.rs

@@ -1,12 +1,16 @@
 //! MTProto Handshake
 
+#![allow(dead_code)]
+
 use std::net::SocketAddr;
 use std::sync::Arc;
+use std::time::Duration;
 use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt};
-use tracing::{debug, warn, trace, info};
+use tracing::{debug, warn, trace};
 use zeroize::Zeroize;
 
 use crate::crypto::{sha256, AesCtr, SecureRandom};
+use rand::Rng;
 use crate::protocol::constants::*;
 use crate::protocol::tls;
 use crate::stream::{FakeTlsReader, FakeTlsWriter, CryptoReader, CryptoWriter};
@@ -15,6 +19,31 @@ use crate::stats::ReplayChecker;
 use crate::config::ProxyConfig;
 use crate::tls_front::{TlsFrontCache, emulator};
 
+fn decode_user_secrets(
+    config: &ProxyConfig,
+    preferred_user: Option<&str>,
+) -> Vec<(String, Vec<u8>)> {
+    let mut secrets = Vec::with_capacity(config.access.users.len());
+
+    if let Some(preferred) = preferred_user
+        && let Some(secret_hex) = config.access.users.get(preferred)
+        && let Ok(bytes) = hex::decode(secret_hex)
+    {
+        secrets.push((preferred.to_string(), bytes));
+    }
+
+    for (name, secret_hex) in &config.access.users {
+        if preferred_user.is_some_and(|preferred| preferred == name.as_str()) {
+            continue;
+        }
+        if let Ok(bytes) = hex::decode(secret_hex) {
+            secrets.push((name.clone(), bytes));
+        }
+    }
+
+    secrets
+}
+
 /// Result of successful handshake
 ///
 /// Key material (`dec_key`, `dec_iv`, `enc_key`, `enc_iv`) is
@@ -78,11 +107,7 @@ where
         return HandshakeResult::BadClient { reader, writer };
     }
 
-    let secrets: Vec<(String, Vec<u8>)> = config.access.users.iter()
-        .filter_map(|(name, hex)| {
-            hex::decode(hex).ok().map(|bytes| (name.clone(), bytes))
-        })
-        .collect();
+    let secrets = decode_user_secrets(config, None);
 
     let validation = match tls::validate_tls_handshake(
         handshake,
@@ -107,11 +132,23 @@ where
 
     let cached = if config.censorship.tls_emulation {
         if let Some(cache) = tls_cache.as_ref() {
-            if let Some(sni) = tls::extract_sni_from_client_hello(handshake) {
-                Some(cache.get(&sni).await)
+            let selected_domain = if let Some(sni) = tls::extract_sni_from_client_hello(handshake) {
+                if cache.contains_domain(&sni).await {
+                    sni
+                } else {
+                    config.censorship.tls_domain.clone()
+                }
             } else {
-                Some(cache.get(&config.censorship.tls_domain).await)
-            }
+                config.censorship.tls_domain.clone()
+            };
+            let cached_entry = cache.get(&selected_domain).await;
+            let use_full_cert_payload = cache
+                .take_full_cert_budget_for_ip(
+                    peer.ip(),
+                    Duration::from_secs(config.censorship.tls_full_cert_ttl_secs),
+                )
+                .await;
+            Some((cached_entry, use_full_cert_payload))
         } else {
             None
         }
@@ -119,13 +156,33 @@ where
         None
     };
 
-    let response = if let Some(cached_entry) = cached {
+    let alpn_list = if config.censorship.alpn_enforce {
+        tls::extract_alpn_from_client_hello(handshake)
+    } else {
+        Vec::new()
+    };
+    let selected_alpn = if config.censorship.alpn_enforce {
+        if alpn_list.iter().any(|p| p == b"h2") {
+            Some(b"h2".to_vec())
+        } else if alpn_list.iter().any(|p| p == b"http/1.1") {
+            Some(b"http/1.1".to_vec())
+        } else {
+            None
+        }
+    } else {
+        None
+    };
+
+    let response = if let Some((cached_entry, use_full_cert_payload)) = cached {
         emulator::build_emulated_server_hello(
             secret,
             &validation.digest,
             &validation.session_id,
             &cached_entry,
+            use_full_cert_payload,
             rng,
+            selected_alpn.clone(),
+            config.censorship.tls_new_session_tickets,
         )
     } else {
         tls::build_server_hello(
@@ -134,9 +191,25 @@ where
             &validation.session_id,
             config.censorship.fake_cert_len,
             rng,
+            selected_alpn.clone(),
+            config.censorship.tls_new_session_tickets,
         )
     };
 
+    // Optional anti-fingerprint delay before sending ServerHello.
+    if config.censorship.server_hello_delay_max_ms > 0 {
+        let min = config.censorship.server_hello_delay_min_ms;
+        let max = config.censorship.server_hello_delay_max_ms.max(min);
+        let delay_ms = if max == min {
+            max
+        } else {
+            rand::rng().random_range(min..=max)
+        };
+        if delay_ms > 0 {
+            tokio::time::sleep(std::time::Duration::from_millis(delay_ms)).await;
+        }
+    }
+
     debug!(peer = %peer, response_len = response.len(), "Sending TLS ServerHello");
 
     if let Err(e) = writer.write_all(&response).await {
@@ -149,7 +222,7 @@ where
         return HandshakeResult::Error(ProxyError::Io(e));
     }
 
-    info!(
+    debug!(
         peer = %peer,
         user = %validation.user,
         "TLS handshake successful"
@@ -171,6 +244,7 @@ pub async fn handle_mtproto_handshake<R, W>(
     config: &ProxyConfig,
     replay_checker: &ReplayChecker,
     is_tls: bool,
+    preferred_user: Option<&str>,
 ) -> HandshakeResult<(CryptoReader<R>, CryptoWriter<W>, HandshakeSuccess), R, W>
 where
     R: AsyncRead + Unpin + Send,
@@ -187,11 +261,9 @@ where
 
     let enc_prekey_iv: Vec<u8> = dec_prekey_iv.iter().rev().copied().collect();
 
-    for (user, secret_hex) in &config.access.users {
-        let secret = match hex::decode(secret_hex) {
-            Ok(s) => s,
-            Err(_) => continue,
-        };
+    let decoded_users = decode_user_secrets(config, preferred_user);
+
+    for (user, secret) in decoded_users {
 
         let dec_prekey = &dec_prekey_iv[..PREKEY_LEN];
         let dec_iv_bytes = &dec_prekey_iv[PREKEY_LEN..];
@@ -217,7 +289,11 @@ where
 
         let mode_ok = match proto_tag {
             ProtoTag::Secure => {
-                if is_tls { config.general.modes.tls } else { config.general.modes.secure }
+                if is_tls {
+                    config.general.modes.tls || config.general.modes.secure
+                } else {
+                    config.general.modes.secure || config.general.modes.tls
+                }
             }
             ProtoTag::Intermediate | ProtoTag::Abridged => config.general.modes.classic,
         };
@@ -255,7 +331,7 @@ where
             is_tls,
         };
 
-        info!(
+        debug!(
             peer = %peer,
             user = %user,
             dc = dc_idx,
@@ -264,9 +340,10 @@ where
             "MTProto handshake successful"
         );
 
+        let max_pending = config.general.crypto_pending_buffer;
         return HandshakeResult::Success((
             CryptoReader::new(reader, decryptor),
-            CryptoWriter::new(writer, encryptor),
+            CryptoWriter::new(writer, encryptor, max_pending),
             success,
         ));
     }

src/proxy/masking.rs

@@ -1,6 +1,7 @@
 //! Masking - forward unrecognized traffic to mask host
 
 use std::str;
+use std::net::SocketAddr;
 use std::time::Duration;
 use tokio::net::TcpStream;
 #[cfg(unix)]
@@ -9,6 +10,9 @@ use tokio::io::{AsyncRead, AsyncWrite, AsyncReadExt, AsyncWriteExt};
 use tokio::time::timeout;
 use tracing::debug;
 use crate::config::ProxyConfig;
+use crate::network::dns_overrides::resolve_socket_addr;
+use crate::stats::beobachten::BeobachtenStore;
+use crate::transport::proxy_protocol::{ProxyProtocolV1Builder, ProxyProtocolV2Builder};
 
 const MASK_TIMEOUT: Duration = Duration::from_secs(5);
 /// Maximum duration for the entire masking relay.
@@ -19,12 +23,12 @@ const MASK_BUFFER_SIZE: usize = 8192;
 /// Detect client type based on initial data
 fn detect_client_type(data: &[u8]) -> &'static str {
     // Check for HTTP request
-    if data.len() > 4 {
-        if data.starts_with(b"GET ") || data.starts_with(b"POST") ||
+    if data.len() > 4
+        && (data.starts_with(b"GET ") || data.starts_with(b"POST") ||
            data.starts_with(b"HEAD") || data.starts_with(b"PUT ") ||
-           data.starts_with(b"DELETE") || data.starts_with(b"OPTIONS") {
-            return "HTTP";
-        }
+           data.starts_with(b"DELETE") || data.starts_with(b"OPTIONS"))
+    {
+        return "HTTP";
     }
 
     // Check for TLS ClientHello (0x16 = handshake, 0x03 0x01-0x03 = TLS version)
@@ -50,20 +54,27 @@ pub async fn handle_bad_client<R, W>(
     reader: R,
     writer: W,
     initial_data: &[u8],
+    peer: SocketAddr,
+    local_addr: SocketAddr,
     config: &ProxyConfig,
+    beobachten: &BeobachtenStore,
 )
 where
     R: AsyncRead + Unpin + Send + 'static,
     W: AsyncWrite + Unpin + Send + 'static,
 {
+    let client_type = detect_client_type(initial_data);
+    if config.general.beobachten {
+        let ttl = Duration::from_secs(config.general.beobachten_minutes.saturating_mul(60));
+        beobachten.record(client_type, peer.ip(), ttl);
+    }
+
     if !config.censorship.mask {
         // Masking disabled, just consume data
         consume_client_data(reader).await;
         return;
     }
 
-    let client_type = detect_client_type(initial_data);
-
     // Connect via Unix socket or TCP
     #[cfg(unix)]
     if let Some(ref sock_path) = config.censorship.mask_unix_sock {
@@ -77,7 +88,29 @@ where
         let connect_result = timeout(MASK_TIMEOUT, UnixStream::connect(sock_path)).await;
         match connect_result {
             Ok(Ok(stream)) => {
-                let (mask_read, mask_write) = stream.into_split();
+                let (mask_read, mut mask_write) = stream.into_split();
+                let proxy_header: Option<Vec<u8>> = match config.censorship.mask_proxy_protocol {
+                    0 => None,
+                    version => {
+                        let header = match version {
+                            2 => ProxyProtocolV2Builder::new().with_addrs(peer, local_addr).build(),
+                            _ => match (peer, local_addr) {
+                                (SocketAddr::V4(src), SocketAddr::V4(dst)) =>
+                                    ProxyProtocolV1Builder::new().tcp4(src.into(), dst.into()).build(),
+                                (SocketAddr::V6(src), SocketAddr::V6(dst)) =>
+                                    ProxyProtocolV1Builder::new().tcp6(src.into(), dst.into()).build(),
+                                _ =>
+                                    ProxyProtocolV1Builder::new().build(),
+                            },
+                        };
+                        Some(header)
+                    }
+                };
+                if let Some(header) = proxy_header {
+                    if mask_write.write_all(&header).await.is_err() {
+                        return;
+                    }
+                }
                 if timeout(MASK_RELAY_TIMEOUT, relay_to_mask(reader, writer, mask_read, mask_write, initial_data)).await.is_err() {
                     debug!("Mask relay timed out (unix socket)");
                 }
@@ -106,12 +139,37 @@ where
         "Forwarding bad client to mask host"
     );
 
-    // Connect to mask host
-    let mask_addr = format!("{}:{}", mask_host, mask_port);
+    // Apply runtime DNS override for mask target when configured.
+    let mask_addr = resolve_socket_addr(mask_host, mask_port)
+        .map(|addr| addr.to_string())
+        .unwrap_or_else(|| format!("{}:{}", mask_host, mask_port));
     let connect_result = timeout(MASK_TIMEOUT, TcpStream::connect(&mask_addr)).await;
     match connect_result {
         Ok(Ok(stream)) => {
-            let (mask_read, mask_write) = stream.into_split();
+            let proxy_header: Option<Vec<u8>> = match config.censorship.mask_proxy_protocol {
+                0 => None,
+                version => {
+                    let header = match version {
+                        2 => ProxyProtocolV2Builder::new().with_addrs(peer, local_addr).build(),
+                        _ => match (peer, local_addr) {
+                            (SocketAddr::V4(src), SocketAddr::V4(dst)) =>
+                                ProxyProtocolV1Builder::new().tcp4(src.into(), dst.into()).build(),
+                            (SocketAddr::V6(src), SocketAddr::V6(dst)) =>
+                                ProxyProtocolV1Builder::new().tcp6(src.into(), dst.into()).build(),
+                            _ =>
+                                ProxyProtocolV1Builder::new().build(),
+                        },
+                    };
+                    Some(header)
+                }
+            };
+
+            let (mask_read, mut mask_write) = stream.into_split();
+            if let Some(header) = proxy_header {
+                if mask_write.write_all(&header).await.is_err() {
+                    return;
+                }
+            }
             if timeout(MASK_RELAY_TIMEOUT, relay_to_mask(reader, writer, mask_read, mask_write, initial_data)).await.is_err() {
                 debug!("Mask relay timed out");
             }

src/proxy/middle_relay.rs

@@ -1,25 +1,202 @@
-use std::net::SocketAddr;
-use std::sync::Arc;
+use std::collections::HashMap;
+use std::collections::hash_map::DefaultHasher;
+use std::hash::{Hash, Hasher};
+use std::net::{IpAddr, SocketAddr};
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::{Arc, Mutex, OnceLock};
+use std::time::{Duration, Instant};
 
 use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
-use tracing::{debug, info, trace};
+use tokio::sync::{mpsc, oneshot};
+use tracing::{debug, trace, warn};
 
 use crate::config::ProxyConfig;
 use crate::crypto::SecureRandom;
 use crate::error::{ProxyError, Result};
-use crate::protocol::constants::*;
+use crate::protocol::constants::{*, secure_padding_len};
 use crate::proxy::handshake::HandshakeSuccess;
 use crate::stats::Stats;
 use crate::stream::{BufferPool, CryptoReader, CryptoWriter};
 use crate::transport::middle_proxy::{MePool, MeResponse, proto_flags_for_tag};
 
+enum C2MeCommand {
+    Data { payload: Vec<u8>, flags: u32 },
+    Close,
+}
+
+const DESYNC_DEDUP_WINDOW: Duration = Duration::from_secs(60);
+const DESYNC_ERROR_CLASS: &str = "frame_too_large_crypto_desync";
+const C2ME_CHANNEL_CAPACITY: usize = 1024;
+const C2ME_SOFT_PRESSURE_MIN_FREE_SLOTS: usize = 64;
+const C2ME_SENDER_FAIRNESS_BUDGET: usize = 32;
+static DESYNC_DEDUP: OnceLock<Mutex<HashMap<u64, Instant>>> = OnceLock::new();
+
+struct RelayForensicsState {
+    trace_id: u64,
+    conn_id: u64,
+    user: String,
+    peer: SocketAddr,
+    peer_hash: u64,
+    started_at: Instant,
+    bytes_c2me: u64,
+    bytes_me2c: Arc<AtomicU64>,
+    desync_all_full: bool,
+}
+
+fn hash_value<T: Hash>(value: &T) -> u64 {
+    let mut hasher = DefaultHasher::new();
+    value.hash(&mut hasher);
+    hasher.finish()
+}
+
+fn hash_ip(ip: IpAddr) -> u64 {
+    hash_value(&ip)
+}
+
+fn should_emit_full_desync(key: u64, all_full: bool, now: Instant) -> bool {
+    if all_full {
+        return true;
+    }
+
+    let dedup = DESYNC_DEDUP.get_or_init(|| Mutex::new(HashMap::new()));
+    let mut guard = dedup.lock().expect("desync dedup mutex poisoned");
+    guard.retain(|_, seen_at| now.duration_since(*seen_at) < DESYNC_DEDUP_WINDOW);
+
+    match guard.get_mut(&key) {
+        Some(seen_at) => {
+            if now.duration_since(*seen_at) >= DESYNC_DEDUP_WINDOW {
+                *seen_at = now;
+                true
+            } else {
+                false
+            }
+        }
+        None => {
+            guard.insert(key, now);
+            true
+        }
+    }
+}
+
+fn report_desync_frame_too_large(
+    state: &RelayForensicsState,
+    proto_tag: ProtoTag,
+    frame_counter: u64,
+    max_frame: usize,
+    len: usize,
+    raw_len_bytes: Option<[u8; 4]>,
+    stats: &Stats,
+) -> ProxyError {
+    let len_buf = raw_len_bytes.unwrap_or((len as u32).to_le_bytes());
+    let looks_like_tls = raw_len_bytes
+        .map(|b| b[0] == 0x16 && b[1] == 0x03)
+        .unwrap_or(false);
+    let looks_like_http = raw_len_bytes
+        .map(|b| matches!(b[0], b'G' | b'P' | b'H' | b'C' | b'D'))
+        .unwrap_or(false);
+    let now = Instant::now();
+    let dedup_key = hash_value(&(
+        state.user.as_str(),
+        state.peer_hash,
+        proto_tag,
+        DESYNC_ERROR_CLASS,
+    ));
+    let emit_full = should_emit_full_desync(dedup_key, state.desync_all_full, now);
+    let duration_ms = state.started_at.elapsed().as_millis() as u64;
+    let bytes_me2c = state.bytes_me2c.load(Ordering::Relaxed);
+
+    stats.increment_desync_total();
+    stats.observe_desync_frames_ok(frame_counter);
+    if emit_full {
+        stats.increment_desync_full_logged();
+        warn!(
+            trace_id = format_args!("0x{:016x}", state.trace_id),
+            conn_id = state.conn_id,
+            user = %state.user,
+            peer_hash = format_args!("0x{:016x}", state.peer_hash),
+            proto = ?proto_tag,
+            mode = "middle_proxy",
+            is_tls = true,
+            duration_ms,
+            bytes_c2me = state.bytes_c2me,
+            bytes_me2c,
+            raw_len = len,
+            raw_len_hex = format_args!("0x{:08x}", len),
+            raw_bytes = format_args!(
+                "{:02x} {:02x} {:02x} {:02x}",
+                len_buf[0], len_buf[1], len_buf[2], len_buf[3]
+            ),
+            max_frame,
+            tls_like = looks_like_tls,
+            http_like = looks_like_http,
+            frames_ok = frame_counter,
+            dedup_window_secs = DESYNC_DEDUP_WINDOW.as_secs(),
+            desync_all_full = state.desync_all_full,
+            full_reason = if state.desync_all_full { "desync_all_full" } else { "first_in_dedup_window" },
+            error_class = DESYNC_ERROR_CLASS,
+            "Frame too large — crypto desync forensics"
+        );
+        debug!(
+            trace_id = format_args!("0x{:016x}", state.trace_id),
+            conn_id = state.conn_id,
+            user = %state.user,
+            peer = %state.peer,
+            "Frame too large forensic peer detail"
+        );
+    } else {
+        stats.increment_desync_suppressed();
+        debug!(
+            trace_id = format_args!("0x{:016x}", state.trace_id),
+            conn_id = state.conn_id,
+            user = %state.user,
+            peer_hash = format_args!("0x{:016x}", state.peer_hash),
+            proto = ?proto_tag,
+            duration_ms,
+            bytes_c2me = state.bytes_c2me,
+            bytes_me2c,
+            raw_len = len,
+            frames_ok = frame_counter,
+            dedup_window_secs = DESYNC_DEDUP_WINDOW.as_secs(),
+            error_class = DESYNC_ERROR_CLASS,
+            "Frame too large — crypto desync forensic suppressed"
+        );
+    }
+
+    ProxyError::Proxy(format!(
+        "Frame too large: {len} (max {max_frame}), frames_ok={frame_counter}, conn_id={}, trace_id=0x{:016x}",
+        state.conn_id,
+        state.trace_id
+    ))
+}
+
+fn should_yield_c2me_sender(sent_since_yield: usize, has_backlog: bool) -> bool {
+    has_backlog && sent_since_yield >= C2ME_SENDER_FAIRNESS_BUDGET
+}
+
+async fn enqueue_c2me_command(
+    tx: &mpsc::Sender<C2MeCommand>,
+    cmd: C2MeCommand,
+) -> std::result::Result<(), mpsc::error::SendError<C2MeCommand>> {
+    match tx.try_send(cmd) {
+        Ok(()) => Ok(()),
+        Err(mpsc::error::TrySendError::Closed(cmd)) => Err(mpsc::error::SendError(cmd)),
+        Err(mpsc::error::TrySendError::Full(cmd)) => {
+            // Cooperative yield reduces burst catch-up when the per-conn queue is near saturation.
+            if tx.capacity() <= C2ME_SOFT_PRESSURE_MIN_FREE_SLOTS {
+                tokio::task::yield_now().await;
+            }
+            tx.send(cmd).await
+        }
+    }
+}
+
 pub(crate) async fn handle_via_middle_proxy<R, W>(
     mut crypto_reader: CryptoReader<R>,
-    mut crypto_writer: CryptoWriter<W>,
+    crypto_writer: CryptoWriter<W>,
     success: HandshakeSuccess,
     me_pool: Arc<MePool>,
     stats: Arc<Stats>,
-    _config: Arc<ProxyConfig>,
+    config: Arc<ProxyConfig>,
     _buffer_pool: Arc<BufferPool>,
     local_addr: SocketAddr,
     rng: Arc<SecureRandom>,
@@ -31,88 +208,266 @@ where
     let user = success.user.clone();
     let peer = success.peer;
     let proto_tag = success.proto_tag;
+    let pool_generation = me_pool.current_generation();
 
-    info!(
+    debug!(
         user = %user,
         peer = %peer,
         dc = success.dc_idx,
         proto = ?proto_tag,
         mode = "middle_proxy",
+        pool_generation,
         "Routing via Middle-End"
     );
 
-    let (conn_id, mut me_rx) = me_pool.registry().register().await;
+    let (conn_id, me_rx) = me_pool.registry().register().await;
+    let trace_id = conn_id;
+    let bytes_me2c = Arc::new(AtomicU64::new(0));
+    let mut forensics = RelayForensicsState {
+        trace_id,
+        conn_id,
+        user: user.clone(),
+        peer,
+        peer_hash: hash_ip(peer.ip()),
+        started_at: Instant::now(),
+        bytes_c2me: 0,
+        bytes_me2c: bytes_me2c.clone(),
+        desync_all_full: config.general.desync_all_full,
+    };
 
     stats.increment_user_connects(&user);
     stats.increment_user_curr_connects(&user);
+    stats.increment_current_connections_me();
 
-    let proto_flags = proto_flags_for_tag(proto_tag, me_pool.has_proxy_tag());
+    // Per-user ad_tag from access.user_ad_tags; fallback to general.ad_tag (hot-reloadable)
+    let user_tag: Option<Vec<u8>> = config
+        .access
+        .user_ad_tags
+        .get(&user)
+        .and_then(|s| hex::decode(s).ok())
+        .filter(|v| v.len() == 16);
+    let global_tag: Option<Vec<u8>> = config
+        .general
+        .ad_tag
+        .as_ref()
+        .and_then(|s| hex::decode(s).ok())
+        .filter(|v| v.len() == 16);
+    let effective_tag = user_tag.or(global_tag);
+
+    let proto_flags = proto_flags_for_tag(proto_tag, effective_tag.is_some());
     debug!(
+        trace_id = format_args!("0x{:016x}", trace_id),
         user = %user,
         conn_id,
+        peer_hash = format_args!("0x{:016x}", forensics.peer_hash),
+        desync_all_full = forensics.desync_all_full,
         proto_flags = format_args!("0x{:08x}", proto_flags),
+        pool_generation,
         "ME relay started"
     );
 
     let translated_local_addr = me_pool.translate_our_addr(local_addr);
 
-    let result: Result<()> = loop {
-        tokio::select! {
-            client_frame = read_client_payload(&mut crypto_reader, proto_tag) => {
-                match client_frame {
-                    Ok(Some((payload, quickack))) => {
-                        trace!(conn_id, bytes = payload.len(), "C->ME frame");
-                        stats.add_user_octets_from(&user, payload.len() as u64);
-                        let mut flags = proto_flags;
-                        if quickack {
-                            flags |= RPC_FLAG_QUICKACK;
-                        }
-                        if payload.len() >= 8 && payload[..8].iter().all(|b| *b == 0) {
-                            flags |= RPC_FLAG_NOT_ENCRYPTED;
-                        }
-                        me_pool.send_proxy_req(
-                            conn_id,
-                            success.dc_idx,
-                            peer,
-                            translated_local_addr,
-                            &payload,
-                            flags,
-                        ).await?;
+    let frame_limit = config.general.max_client_frame;
+
+    let (c2me_tx, mut c2me_rx) = mpsc::channel::<C2MeCommand>(C2ME_CHANNEL_CAPACITY);
+    let me_pool_c2me = me_pool.clone();
+    let effective_tag = effective_tag;
+    let c2me_sender = tokio::spawn(async move {
+        let mut sent_since_yield = 0usize;
+        while let Some(cmd) = c2me_rx.recv().await {
+            match cmd {
+                C2MeCommand::Data { payload, flags } => {
+                    me_pool_c2me.send_proxy_req(
+                        conn_id,
+                        success.dc_idx,
+                        peer,
+                        translated_local_addr,
+                        &payload,
+                        flags,
+                        effective_tag.as_deref(),
+                    ).await?;
+                    sent_since_yield = sent_since_yield.saturating_add(1);
+                    if should_yield_c2me_sender(sent_since_yield, !c2me_rx.is_empty()) {
+                        sent_since_yield = 0;
+                        tokio::task::yield_now().await;
                     }
-                    Ok(None) => {
-                        debug!(conn_id, "Client EOF");
-                        let _ = me_pool.send_close(conn_id).await;
-                        break Ok(());
-                    }
-                    Err(e) => break Err(e),
                 }
-            }
-            me_msg = me_rx.recv() => {
-                match me_msg {
-                    Some(MeResponse::Data { flags, data }) => {
-                        trace!(conn_id, bytes = data.len(), flags, "ME->C data");
-                        stats.add_user_octets_to(&user, data.len() as u64);
-                        write_client_payload(&mut crypto_writer, proto_tag, flags, &data, rng.as_ref()).await?;
-                    }
-                    Some(MeResponse::Ack(confirm)) => {
-                        trace!(conn_id, confirm, "ME->C quickack");
-                        write_client_ack(&mut crypto_writer, proto_tag, confirm).await?;
-                    }
-                    Some(MeResponse::Close) => {
-                        debug!(conn_id, "ME sent close");
-                        break Ok(());
-                    }
-                    None => {
-                        debug!(conn_id, "ME channel closed");
-                        break Err(ProxyError::Proxy("ME connection lost".into()));
-                    }
+                C2MeCommand::Close => {
+                    let _ = me_pool_c2me.send_close(conn_id).await;
+                    return Ok(());
                 }
             }
         }
+        Ok(())
+    });
+
+    let (stop_tx, mut stop_rx) = oneshot::channel::<()>();
+    let mut me_rx_task = me_rx;
+    let stats_clone = stats.clone();
+    let rng_clone = rng.clone();
+    let user_clone = user.clone();
+    let bytes_me2c_clone = bytes_me2c.clone();
+    let me_writer = tokio::spawn(async move {
+        let mut writer = crypto_writer;
+        let mut frame_buf = Vec::with_capacity(16 * 1024);
+        loop {
+            tokio::select! {
+                msg = me_rx_task.recv() => {
+                    match msg {
+                        Some(MeResponse::Data { flags, data }) => {
+                            trace!(conn_id, bytes = data.len(), flags, "ME->C data");
+                            bytes_me2c_clone.fetch_add(data.len() as u64, Ordering::Relaxed);
+                            stats_clone.add_user_octets_to(&user_clone, data.len() as u64);
+                            write_client_payload(
+                                &mut writer,
+                                proto_tag,
+                                flags,
+                                &data,
+                                rng_clone.as_ref(),
+                                &mut frame_buf,
+                            )
+                            .await?;
+
+                            // Drain all immediately queued ME responses and flush once.
+                            while let Ok(next) = me_rx_task.try_recv() {
+                                match next {
+                                    MeResponse::Data { flags, data } => {
+                                        trace!(conn_id, bytes = data.len(), flags, "ME->C data (batched)");
+                                        bytes_me2c_clone.fetch_add(data.len() as u64, Ordering::Relaxed);
+                                        stats_clone.add_user_octets_to(&user_clone, data.len() as u64);
+                                        write_client_payload(
+                                            &mut writer,
+                                            proto_tag,
+                                            flags,
+                                            &data,
+                                            rng_clone.as_ref(),
+                                            &mut frame_buf,
+                                        ).await?;
+                                    }
+                                    MeResponse::Ack(confirm) => {
+                                        trace!(conn_id, confirm, "ME->C quickack (batched)");
+                                        write_client_ack(&mut writer, proto_tag, confirm).await?;
+                                    }
+                                    MeResponse::Close => {
+                                        debug!(conn_id, "ME sent close (batched)");
+                                        let _ = writer.flush().await;
+                                        return Ok(());
+                                    }
+                                }
+                            }
+
+                            writer.flush().await.map_err(ProxyError::Io)?;
+                        }
+                        Some(MeResponse::Ack(confirm)) => {
+                            trace!(conn_id, confirm, "ME->C quickack");
+                            write_client_ack(&mut writer, proto_tag, confirm).await?;
+                        }
+                        Some(MeResponse::Close) => {
+                            debug!(conn_id, "ME sent close");
+                            let _ = writer.flush().await;
+                            return Ok(());
+                        }
+                        None => {
+                            debug!(conn_id, "ME channel closed");
+                            return Err(ProxyError::Proxy("ME connection lost".into()));
+                        }
+                    }
+                }
+                _ = &mut stop_rx => {
+                    debug!(conn_id, "ME writer stop signal");
+                    return Ok(());
+                }
+            }
+        }
+    });
+
+    let mut main_result: Result<()> = Ok(());
+    let mut client_closed = false;
+    let mut frame_counter: u64 = 0;
+    loop {
+        match read_client_payload(
+            &mut crypto_reader,
+            proto_tag,
+            frame_limit,
+            &forensics,
+            &mut frame_counter,
+            &stats,
+        ).await {
+            Ok(Some((payload, quickack))) => {
+                trace!(conn_id, bytes = payload.len(), "C->ME frame");
+                forensics.bytes_c2me = forensics
+                    .bytes_c2me
+                    .saturating_add(payload.len() as u64);
+                stats.add_user_octets_from(&user, payload.len() as u64);
+                let mut flags = proto_flags;
+                if quickack {
+                    flags |= RPC_FLAG_QUICKACK;
+                }
+                if payload.len() >= 8 && payload[..8].iter().all(|b| *b == 0) {
+                    flags |= RPC_FLAG_NOT_ENCRYPTED;
+                }
+                // Keep client read loop lightweight: route heavy ME send path via a dedicated task.
+                if enqueue_c2me_command(&c2me_tx, C2MeCommand::Data { payload, flags })
+                    .await
+                    .is_err()
+                {
+                    main_result = Err(ProxyError::Proxy("ME sender channel closed".into()));
+                    break;
+                }
+            }
+            Ok(None) => {
+                debug!(conn_id, "Client EOF");
+                client_closed = true;
+                let _ = enqueue_c2me_command(&c2me_tx, C2MeCommand::Close).await;
+                break;
+            }
+            Err(e) => {
+                main_result = Err(e);
+                break;
+            }
+        }
+    }
+
+    drop(c2me_tx);
+    let c2me_result = c2me_sender
+        .await
+        .unwrap_or_else(|e| Err(ProxyError::Proxy(format!("ME sender join error: {e}"))));
+
+    let _ = stop_tx.send(());
+    let mut writer_result = me_writer
+        .await
+        .unwrap_or_else(|e| Err(ProxyError::Proxy(format!("ME writer join error: {e}"))));
+
+    // When client closes, but ME channel stopped as unregistered - it isnt error
+    if client_closed
+        && matches!(
+            writer_result,
+            Err(ProxyError::Proxy(ref msg)) if msg == "ME connection lost"
+        )
+    {
+        writer_result = Ok(());
+    }
+
+    let result = match (main_result, c2me_result, writer_result) {
+        (Ok(()), Ok(()), Ok(())) => Ok(()),
+        (Err(e), _, _) => Err(e),
+        (_, Err(e), _) => Err(e),
+        (_, _, Err(e)) => Err(e),
     };
 
-    debug!(user = %user, conn_id, "ME relay cleanup");
+    debug!(
+        user = %user,
+        conn_id,
+        trace_id = format_args!("0x{:016x}", trace_id),
+        duration_ms = forensics.started_at.elapsed().as_millis() as u64,
+        bytes_c2me = forensics.bytes_c2me,
+        bytes_me2c = forensics.bytes_me2c.load(Ordering::Relaxed),
+        frames_ok = frame_counter,
+        "ME relay cleanup"
+    );
     me_pool.registry().unregister(conn_id).await;
+    stats.decrement_current_connections_me();
     stats.decrement_user_curr_connects(&user);
     result
 }
@@ -120,66 +475,111 @@ where
 async fn read_client_payload<R>(
     client_reader: &mut CryptoReader<R>,
     proto_tag: ProtoTag,
+    max_frame: usize,
+    forensics: &RelayForensicsState,
+    frame_counter: &mut u64,
+    stats: &Stats,
 ) -> Result<Option<(Vec<u8>, bool)>>
 where
     R: AsyncRead + Unpin + Send + 'static,
 {
-    let (len, quickack) = match proto_tag {
-        ProtoTag::Abridged => {
-            let mut first = [0u8; 1];
-            match client_reader.read_exact(&mut first).await {
-                Ok(_) => {}
-                Err(e) if e.kind() == std::io::ErrorKind::UnexpectedEof => return Ok(None),
-                Err(e) => return Err(ProxyError::Io(e)),
+    loop {
+        let (len, quickack, raw_len_bytes) = match proto_tag {
+            ProtoTag::Abridged => {
+                let mut first = [0u8; 1];
+                match client_reader.read_exact(&mut first).await {
+                    Ok(_) => {}
+                    Err(e) if e.kind() == std::io::ErrorKind::UnexpectedEof => return Ok(None),
+                    Err(e) => return Err(ProxyError::Io(e)),
+                }
+
+                let quickack = (first[0] & 0x80) != 0;
+                let len_words = if (first[0] & 0x7f) == 0x7f {
+                    let mut ext = [0u8; 3];
+                    client_reader
+                        .read_exact(&mut ext)
+                        .await
+                        .map_err(ProxyError::Io)?;
+                    u32::from_le_bytes([ext[0], ext[1], ext[2], 0]) as usize
+                } else {
+                    (first[0] & 0x7f) as usize
+                };
+
+                let len = len_words
+                    .checked_mul(4)
+                    .ok_or_else(|| ProxyError::Proxy("Abridged frame length overflow".into()))?;
+                (len, quickack, None)
             }
-
-            let quickack = (first[0] & 0x80) != 0;
-            let len_words = if (first[0] & 0x7f) == 0x7f {
-                let mut ext = [0u8; 3];
-                client_reader
-                    .read_exact(&mut ext)
-                    .await
-                    .map_err(ProxyError::Io)?;
-                u32::from_le_bytes([ext[0], ext[1], ext[2], 0]) as usize
-            } else {
-                (first[0] & 0x7f) as usize
-            };
-
-            let len = len_words
-                .checked_mul(4)
-                .ok_or_else(|| ProxyError::Proxy("Abridged frame length overflow".into()))?;
-            (len, quickack)
-        }
-        ProtoTag::Intermediate | ProtoTag::Secure => {
-            let mut len_buf = [0u8; 4];
-            match client_reader.read_exact(&mut len_buf).await {
-                Ok(_) => {}
-                Err(e) if e.kind() == std::io::ErrorKind::UnexpectedEof => return Ok(None),
-                Err(e) => return Err(ProxyError::Io(e)),
+            ProtoTag::Intermediate | ProtoTag::Secure => {
+                let mut len_buf = [0u8; 4];
+                match client_reader.read_exact(&mut len_buf).await {
+                    Ok(_) => {}
+                    Err(e) if e.kind() == std::io::ErrorKind::UnexpectedEof => return Ok(None),
+                    Err(e) => return Err(ProxyError::Io(e)),
+                }
+                let quickack = (len_buf[3] & 0x80) != 0;
+                (
+                    (u32::from_le_bytes(len_buf) & 0x7fff_ffff) as usize,
+                    quickack,
+                    Some(len_buf),
+                )
             }
-            let quickack = (len_buf[3] & 0x80) != 0;
-            ((u32::from_le_bytes(len_buf) & 0x7fff_ffff) as usize, quickack)
+        };
+
+        if len == 0 {
+            continue;
         }
-    };
-
-    if len > 16 * 1024 * 1024 {
-        return Err(ProxyError::Proxy(format!("Frame too large: {len}")));
-    }
-
-    let mut payload = vec![0u8; len];
-    client_reader
-        .read_exact(&mut payload)
-        .await
-        .map_err(ProxyError::Io)?;
-
-    // Secure Intermediate: remove random padding (last len%4 bytes)
-    if proto_tag == ProtoTag::Secure {
-        let rem = len % 4;
-        if rem != 0 && payload.len() >= rem {
-            payload.truncate(len - rem);
+        if len < 4 && proto_tag != ProtoTag::Abridged {
+            warn!(
+                trace_id = format_args!("0x{:016x}", forensics.trace_id),
+                conn_id = forensics.conn_id,
+                user = %forensics.user,
+                len,
+                proto = ?proto_tag,
+                "Frame too small — corrupt or probe"
+            );
+            return Err(ProxyError::Proxy(format!("Frame too small: {len}")));
         }
+
+        if len > max_frame {
+            return Err(report_desync_frame_too_large(
+                forensics,
+                proto_tag,
+                *frame_counter,
+                max_frame,
+                len,
+                raw_len_bytes,
+                stats,
+            ));
+        }
+
+        let secure_payload_len = if proto_tag == ProtoTag::Secure {
+            match secure_payload_len_from_wire_len(len) {
+                Some(payload_len) => payload_len,
+                None => {
+                    stats.increment_secure_padding_invalid();
+                    return Err(ProxyError::Proxy(format!(
+                        "Invalid secure frame length: {len}"
+                    )));
+                }
+            }
+        } else {
+            len
+        };
+
+        let mut payload = vec![0u8; len];
+        client_reader
+            .read_exact(&mut payload)
+            .await
+            .map_err(ProxyError::Io)?;
+
+        // Secure Intermediate: strip validated trailing padding bytes.
+        if proto_tag == ProtoTag::Secure {
+            payload.truncate(secure_payload_len);
+        }
+        *frame_counter += 1;
+        return Ok(Some((payload, quickack)));
     }
-    Ok(Some((payload, quickack)))
 }
 
 async fn write_client_payload<W>(
@@ -188,6 +588,7 @@ async fn write_client_payload<W>(
     flags: u32,
     data: &[u8],
     rng: &SecureRandom,
+    frame_buf: &mut Vec<u8>,
 ) -> Result<()>
 where
     W: AsyncWrite + Unpin + Send + 'static,
@@ -196,7 +597,7 @@ where
 
     match proto_tag {
         ProtoTag::Abridged => {
-            if data.len() % 4 != 0 {
+            if !data.len().is_multiple_of(4) {
                 return Err(ProxyError::Proxy(format!(
                     "Abridged payload must be 4-byte aligned, got {}",
                     data.len()
@@ -209,8 +610,12 @@ where
                 if quickack {
                     first |= 0x80;
                 }
+                frame_buf.clear();
+                frame_buf.reserve(1 + data.len());
+                frame_buf.push(first);
+                frame_buf.extend_from_slice(data);
                 client_writer
-                    .write_all(&[first])
+                    .write_all(frame_buf)
                     .await
                     .map_err(ProxyError::Io)?;
             } else if len_words < (1 << 24) {
@@ -219,8 +624,12 @@ where
                     first |= 0x80;
                 }
                 let lw = (len_words as u32).to_le_bytes();
+                frame_buf.clear();
+                frame_buf.reserve(4 + data.len());
+                frame_buf.extend_from_slice(&[first, lw[0], lw[1], lw[2]]);
+                frame_buf.extend_from_slice(data);
                 client_writer
-                    .write_all(&[first, lw[0], lw[1], lw[2]])
+                    .write_all(frame_buf)
                     .await
                     .map_err(ProxyError::Io)?;
             } else {
@@ -229,47 +638,40 @@ where
                     data.len()
                 )));
             }
-
-            client_writer
-                .write_all(data)
-                .await
-                .map_err(ProxyError::Io)?;
         }
         ProtoTag::Intermediate | ProtoTag::Secure => {
             let padding_len = if proto_tag == ProtoTag::Secure {
-                (rng.bytes(1)[0] % 4) as usize
+                if !is_valid_secure_payload_len(data.len()) {
+                    return Err(ProxyError::Proxy(format!(
+                        "Secure payload must be 4-byte aligned, got {}",
+                        data.len()
+                    )));
+                }
+                secure_padding_len(data.len(), rng)
             } else {
                 0
             };
-            let mut len = (data.len() + padding_len) as u32;
+            let mut len_val = (data.len() + padding_len) as u32;
             if quickack {
-                len |= 0x8000_0000;
+                len_val |= 0x8000_0000;
             }
-            client_writer
-                .write_all(&len.to_le_bytes())
-                .await
-                .map_err(ProxyError::Io)?;
-            client_writer
-                .write_all(data)
-                .await
-                .map_err(ProxyError::Io)?;
+            let total = 4 + data.len() + padding_len;
+            frame_buf.clear();
+            frame_buf.reserve(total);
+            frame_buf.extend_from_slice(&len_val.to_le_bytes());
+            frame_buf.extend_from_slice(data);
             if padding_len > 0 {
-                let pad = rng.bytes(padding_len);
-                client_writer
-                    .write_all(&pad)
-                    .await
-                    .map_err(ProxyError::Io)?;
+                let start = frame_buf.len();
+                frame_buf.resize(start + padding_len, 0);
+                rng.fill(&mut frame_buf[start..]);
             }
+            client_writer
+                .write_all(frame_buf)
+                .await
+                .map_err(ProxyError::Io)?;
         }
     }
 
-    // Avoid unconditional per-frame flush (throughput killer on large downloads).
-    // Flush only when low-latency ack semantics are requested or when
-    // CryptoWriter has buffered pending ciphertext that must be drained.
-    if quickack || client_writer.has_pending() {
-        client_writer.flush().await.map_err(ProxyError::Io)?;
-    }
-
     Ok(())
 }
 
@@ -293,3 +695,84 @@ where
     // ACK should remain low-latency.
     client_writer.flush().await.map_err(ProxyError::Io)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tokio::time::{Duration as TokioDuration, timeout};
+
+    #[test]
+    fn should_yield_sender_only_on_budget_with_backlog() {
+        assert!(!should_yield_c2me_sender(0, true));
+        assert!(!should_yield_c2me_sender(C2ME_SENDER_FAIRNESS_BUDGET - 1, true));
+        assert!(!should_yield_c2me_sender(C2ME_SENDER_FAIRNESS_BUDGET, false));
+        assert!(should_yield_c2me_sender(C2ME_SENDER_FAIRNESS_BUDGET, true));
+    }
+
+    #[tokio::test]
+    async fn enqueue_c2me_command_uses_try_send_fast_path() {
+        let (tx, mut rx) = mpsc::channel::<C2MeCommand>(2);
+        enqueue_c2me_command(
+            &tx,
+            C2MeCommand::Data {
+                payload: vec![1, 2, 3],
+                flags: 0,
+            },
+        )
+        .await
+        .unwrap();
+
+        let recv = timeout(TokioDuration::from_millis(50), rx.recv())
+            .await
+            .unwrap()
+            .unwrap();
+        match recv {
+            C2MeCommand::Data { payload, flags } => {
+                assert_eq!(payload, vec![1, 2, 3]);
+                assert_eq!(flags, 0);
+            }
+            C2MeCommand::Close => panic!("unexpected close command"),
+        }
+    }
+
+    #[tokio::test]
+    async fn enqueue_c2me_command_falls_back_to_send_when_queue_is_full() {
+        let (tx, mut rx) = mpsc::channel::<C2MeCommand>(1);
+        tx.send(C2MeCommand::Data {
+            payload: vec![9],
+            flags: 9,
+        })
+        .await
+        .unwrap();
+
+        let tx2 = tx.clone();
+        let producer = tokio::spawn(async move {
+            enqueue_c2me_command(
+                &tx2,
+                C2MeCommand::Data {
+                    payload: vec![7, 7],
+                    flags: 7,
+                },
+            )
+            .await
+            .unwrap();
+        });
+
+        let _ = timeout(TokioDuration::from_millis(100), rx.recv())
+            .await
+            .unwrap();
+        producer.await.unwrap();
+
+        let recv = timeout(TokioDuration::from_millis(100), rx.recv())
+            .await
+            .unwrap()
+            .unwrap();
+        match recv {
+            C2MeCommand::Data { payload, flags } => {
+                assert_eq!(payload, vec![7, 7]);
+                assert_eq!(flags, 7);
+            }
+            C2MeCommand::Close => panic!("unexpected close command"),
+        }
+    }
+}

src/proxy/mod.rs

@@ -8,6 +8,9 @@ pub mod middle_relay;
 pub mod relay;
 
 pub use client::ClientHandler;
+#[allow(unused_imports)]
 pub use handshake::*;
+#[allow(unused_imports)]
 pub use masking::*;
+#[allow(unused_imports)]
 pub use relay::*;

src/stats/beobachten.rs

@@ -0,0 +1,117 @@
+//! Per-IP forensic buckets for scanner and handshake failure observation.
+
+use std::collections::{BTreeMap, HashMap};
+use std::net::IpAddr;
+use std::time::{Duration, Instant};
+
+use parking_lot::Mutex;
+
+const CLEANUP_INTERVAL: Duration = Duration::from_secs(30);
+
+#[derive(Default)]
+struct BeobachtenInner {
+    entries: HashMap<(String, IpAddr), BeobachtenEntry>,
+    last_cleanup: Option<Instant>,
+}
+
+#[derive(Clone, Copy)]
+struct BeobachtenEntry {
+    tries: u64,
+    last_seen: Instant,
+}
+
+/// In-memory, TTL-scoped per-IP counters keyed by source class.
+pub struct BeobachtenStore {
+    inner: Mutex<BeobachtenInner>,
+}
+
+impl Default for BeobachtenStore {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl BeobachtenStore {
+    pub fn new() -> Self {
+        Self {
+            inner: Mutex::new(BeobachtenInner::default()),
+        }
+    }
+
+    pub fn record(&self, class: &str, ip: IpAddr, ttl: Duration) {
+        if class.is_empty() || ttl.is_zero() {
+            return;
+        }
+
+        let now = Instant::now();
+        let mut guard = self.inner.lock();
+        Self::cleanup_if_needed(&mut guard, now, ttl);
+
+        let key = (class.to_string(), ip);
+        let entry = guard.entries.entry(key).or_insert(BeobachtenEntry {
+            tries: 0,
+            last_seen: now,
+        });
+        entry.tries = entry.tries.saturating_add(1);
+        entry.last_seen = now;
+    }
+
+    pub fn snapshot_text(&self, ttl: Duration) -> String {
+        if ttl.is_zero() {
+            return "beobachten disabled\n".to_string();
+        }
+
+        let now = Instant::now();
+        let mut guard = self.inner.lock();
+        Self::cleanup(&mut guard, now, ttl);
+        guard.last_cleanup = Some(now);
+
+        let mut grouped = BTreeMap::<String, Vec<(IpAddr, u64)>>::new();
+        for ((class, ip), entry) in &guard.entries {
+            grouped
+                .entry(class.clone())
+                .or_default()
+                .push((*ip, entry.tries));
+        }
+
+        if grouped.is_empty() {
+            return "empty\n".to_string();
+        }
+
+        let mut out = String::with_capacity(grouped.len() * 64);
+        for (class, entries) in &mut grouped {
+            out.push('[');
+            out.push_str(class);
+            out.push_str("]\n");
+
+            entries.sort_by(|(ip_a, tries_a), (ip_b, tries_b)| {
+                tries_b
+                    .cmp(tries_a)
+                    .then_with(|| ip_a.to_string().cmp(&ip_b.to_string()))
+            });
+
+            for (ip, tries) in entries {
+                out.push_str(&format!("{ip}-{tries}\n"));
+            }
+        }
+
+        out
+    }
+
+    fn cleanup_if_needed(inner: &mut BeobachtenInner, now: Instant, ttl: Duration) {
+        let should_cleanup = match inner.last_cleanup {
+            Some(last) => now.saturating_duration_since(last) >= CLEANUP_INTERVAL,
+            None => true,
+        };
+        if should_cleanup {
+            Self::cleanup(inner, now, ttl);
+            inner.last_cleanup = Some(now);
+        }
+    }
+
+    fn cleanup(inner: &mut BeobachtenInner, now: Instant, ttl: Duration) {
+        inner.entries.retain(|_, entry| {
+            now.saturating_duration_since(entry.last_seen) <= ttl
+        });
+    }
+}

src/stats/telemetry.rs

@@ -0,0 +1,29 @@
+use crate::config::{MeTelemetryLevel, TelemetryConfig};
+
+/// Runtime telemetry policy used by hot-path counters.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct TelemetryPolicy {
+    pub core_enabled: bool,
+    pub user_enabled: bool,
+    pub me_level: MeTelemetryLevel,
+}
+
+impl Default for TelemetryPolicy {
+    fn default() -> Self {
+        Self {
+            core_enabled: true,
+            user_enabled: true,
+            me_level: MeTelemetryLevel::Normal,
+        }
+    }
+}
+
+impl TelemetryPolicy {
+    pub fn from_config(cfg: &TelemetryConfig) -> Self {
+        Self {
+            core_enabled: cfg.core_enabled,
+            user_enabled: cfg.user_enabled,
+            me_level: cfg.me_level,
+        }
+    }
+}

src/stream/buffer_pool.rs

@@ -3,6 +3,8 @@
 //! This module provides a thread-safe pool of BytesMut buffers
 //! that can be reused across connections to reduce allocation pressure.
 
+#![allow(dead_code)]
+
 use bytes::BytesMut;
 use crossbeam_queue::ArrayQueue;
 use std::ops::{Deref, DerefMut};

src/stream/crypto_stream.rs

@@ -18,6 +18,8 @@
 //!   is either written to upstream or stored in our pending buffer
 //! - when upstream is pending -> ciphertext is buffered/bounded and backpressure is applied
 //!
+
+#![allow(dead_code)]
 //! =======================
 //! Writer state machine
 //! =======================
@@ -34,7 +36,7 @@
 //! └────────────────────────────────────────┘
 //!
 //! Backpressure
-//! - pending ciphertext buffer is bounded (MAX_PENDING_WRITE)
+//! - pending ciphertext buffer is bounded (configurable per connection)
 //! - pending is full and upstream is pending 
 //!   -> poll_write returns Poll::Pending
 //!   -> do not accept any plaintext
@@ -45,7 +47,7 @@
 //! - when upstream is Pending but pending still has room: accept `to_accept` bytes and
 //!   encrypt+append ciphertext directly into pending (in-place encryption of appended range)
 
-//! Encrypted stream wrappers using AES-CTR
+//!   Encrypted stream wrappers using AES-CTR
 //!
 //! This module provides stateful async stream wrappers that handle
 //! encryption/decryption with proper partial read/write handling.
@@ -55,17 +57,16 @@ use std::io::{self, ErrorKind, Result};
 use std::pin::Pin;
 use std::task::{Context, Poll};
 use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
-use tracing::{debug, trace, warn};
+use tracing::{debug, trace};
 
 use crate::crypto::AesCtr;
 use super::state::{StreamState, YieldBuffer};
 
 // ============= Constants =============
 
-/// Maximum size for pending ciphertext buffer (bounded backpressure).
-/// Reduced to 64KB to prevent bufferbloat on mobile networks.
-/// 512KB was causing high latency on 3G/LTE connections.
-const MAX_PENDING_WRITE: usize = 64 * 1024;
+/// Default size for pending ciphertext buffer (bounded backpressure).
+/// Actual limit is supplied at runtime from configuration.
+const DEFAULT_MAX_PENDING_WRITE: usize = 64 * 1024;
 
 /// Default read buffer capacity (reader mostly decrypts in-place into caller buffer).
 const DEFAULT_READ_CAPACITY: usize = 16 * 1024;
@@ -152,9 +153,9 @@ impl<R> CryptoReader<R> {
     fn take_poison_error(&mut self) -> io::Error {
         match &mut self.state {
             CryptoReaderState::Poisoned { error } => error.take().unwrap_or_else(|| {
-                io::Error::new(ErrorKind::Other, "stream previously poisoned")
+                io::Error::other("stream previously poisoned")
             }),
-            _ => io::Error::new(ErrorKind::Other, "stream not poisoned"),
+            _ => io::Error::other("stream not poisoned"),
         }
     }
 }
@@ -167,6 +168,7 @@ impl<R: AsyncRead + Unpin> AsyncRead for CryptoReader<R> {
     ) -> Poll<Result<()>> {
         let this = self.get_mut();
 
+        #[allow(clippy::never_loop)]
         loop {
             match &mut this.state {
                 CryptoReaderState::Poisoned { .. } => {
@@ -334,22 +336,35 @@ impl PendingCiphertext {
     }
 
     fn remaining_capacity(&self) -> usize {
-        self.max_len.saturating_sub(self.buf.len())
+        self.max_len.saturating_sub(self.pending_len())
+    }
+
+    fn compact_consumed_prefix(&mut self) {
+        if self.pos == 0 {
+            return;
+        }
+
+        if self.pos >= self.buf.len() {
+            self.buf.clear();
+            self.pos = 0;
+            return;
+        }
+
+        let _ = self.buf.split_to(self.pos);
+        self.pos = 0;
     }
 
     fn advance(&mut self, n: usize) {
         self.pos = (self.pos + n).min(self.buf.len());
 
         if self.pos == self.buf.len() {
-            self.buf.clear();
-            self.pos = 0;
+            self.compact_consumed_prefix();
             return;
         }
 
         // Compact when a large prefix was consumed.
         if self.pos >= 16 * 1024 {
-            let _ = self.buf.split_to(self.pos);
-            self.pos = 0;
+            self.compact_consumed_prefix();
         }
     }
 
@@ -377,6 +392,11 @@ impl PendingCiphertext {
             ));
         }
 
+        // Reclaim consumed prefix when physical storage is the only limiter.
+        if self.pos > 0 && self.buf.len() + plaintext.len() > self.max_len {
+            self.compact_consumed_prefix();
+        }
+
         let start = self.buf.len();
         self.buf.reserve(plaintext.len());
         self.buf.extend_from_slice(plaintext);
@@ -427,15 +447,22 @@ pub struct CryptoWriter<W> {
     encryptor: AesCtr,
     state: CryptoWriterState,
     scratch: BytesMut,
+    max_pending_write: usize,
 }
 
 impl<W> CryptoWriter<W> {
-    pub fn new(upstream: W, encryptor: AesCtr) -> Self {
+    pub fn new(upstream: W, encryptor: AesCtr, max_pending_write: usize) -> Self {
+        let max_pending = if max_pending_write == 0 {
+            DEFAULT_MAX_PENDING_WRITE
+        } else {
+            max_pending_write
+        };
         Self {
             upstream,
             encryptor,
             state: CryptoWriterState::Idle,
             scratch: BytesMut::with_capacity(16 * 1024),
+            max_pending_write: max_pending.max(4 * 1024),
         }
     }
 
@@ -477,17 +504,17 @@ impl<W> CryptoWriter<W> {
     fn take_poison_error(&mut self) -> io::Error {
         match &mut self.state {
             CryptoWriterState::Poisoned { error } => error.take().unwrap_or_else(|| {
-                io::Error::new(ErrorKind::Other, "stream previously poisoned")
+                io::Error::other("stream previously poisoned")
             }),
-            _ => io::Error::new(ErrorKind::Other, "stream not poisoned"),
+            _ => io::Error::other("stream not poisoned"),
         }
     }
 
     /// Ensure we are in Flushing state and return mutable pending buffer.
-    fn ensure_pending<'a>(state: &'a mut CryptoWriterState) -> &'a mut PendingCiphertext {
+    fn ensure_pending(state: &mut CryptoWriterState, max_pending: usize) -> &mut PendingCiphertext {
         if matches!(state, CryptoWriterState::Idle) {
             *state = CryptoWriterState::Flushing {
-                pending: PendingCiphertext::new(MAX_PENDING_WRITE),
+                pending: PendingCiphertext::new(max_pending),
             };
         }
 
@@ -498,14 +525,14 @@ impl<W> CryptoWriter<W> {
     }
 
     /// Select how many plaintext bytes can be accepted in buffering path
-    fn select_to_accept_for_buffering(state: &CryptoWriterState, buf_len: usize) -> usize {
+    fn select_to_accept_for_buffering(state: &CryptoWriterState, buf_len: usize, max_pending: usize) -> usize {
         if buf_len == 0 {
             return 0;
         }
 
         match state {
             CryptoWriterState::Flushing { pending } => buf_len.min(pending.remaining_capacity()),
-            CryptoWriterState::Idle => buf_len.min(MAX_PENDING_WRITE),
+            CryptoWriterState::Idle => buf_len.min(max_pending),
             CryptoWriterState::Poisoned { .. } => 0,
         }
     }
@@ -603,7 +630,7 @@ impl<W: AsyncWrite + Unpin> AsyncWrite for CryptoWriter<W> {
                 Poll::Pending => {
                     // Upstream blocked. Apply ideal backpressure
                     let to_accept =
-                        Self::select_to_accept_for_buffering(&this.state, buf.len());
+                        Self::select_to_accept_for_buffering(&this.state, buf.len(), this.max_pending_write);
 
                     if to_accept == 0 {
                         trace!(
@@ -618,7 +645,7 @@ impl<W: AsyncWrite + Unpin> AsyncWrite for CryptoWriter<W> {
 
                     // Disjoint borrows
                     let encryptor = &mut this.encryptor;
-                    let pending = Self::ensure_pending(&mut this.state);
+                    let pending = Self::ensure_pending(&mut this.state, this.max_pending_write);
 
                     if let Err(e) = pending.push_encrypted(encryptor, plaintext) {
                         if e.kind() == ErrorKind::WouldBlock {
@@ -635,7 +662,7 @@ impl<W: AsyncWrite + Unpin> AsyncWrite for CryptoWriter<W> {
         // 2) Fast path: pending empty -> write-through
         debug_assert!(matches!(this.state, CryptoWriterState::Idle));
 
-        let to_accept = buf.len().min(MAX_PENDING_WRITE);
+        let to_accept = buf.len().min(this.max_pending_write);
         let plaintext = &buf[..to_accept];
 
         Self::encrypt_into_scratch(&mut this.encryptor, &mut this.scratch, plaintext);
@@ -645,7 +672,7 @@ impl<W: AsyncWrite + Unpin> AsyncWrite for CryptoWriter<W> {
                 // Upstream blocked: buffer FULL ciphertext for accepted bytes.
                 let ciphertext = std::mem::take(&mut this.scratch);
 
-                let pending = Self::ensure_pending(&mut this.state);
+                let pending = Self::ensure_pending(&mut this.state, this.max_pending_write);
                 pending.replace_with(ciphertext);
 
                 Poll::Ready(Ok(to_accept))
@@ -672,7 +699,7 @@ impl<W: AsyncWrite + Unpin> AsyncWrite for CryptoWriter<W> {
                 let remainder = this.scratch.split_off(n);
                 this.scratch.clear();
 
-                let pending = Self::ensure_pending(&mut this.state);
+                let pending = Self::ensure_pending(&mut this.state, this.max_pending_write);
                 pending.replace_with(remainder);
 
                 Poll::Ready(Ok(to_accept))
@@ -767,4 +794,71 @@ impl<S: AsyncWrite + Unpin> AsyncWrite for PassthroughStream<S> {
     fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>> {
         Pin::new(&mut self.inner).poll_shutdown(cx)
     }
-}
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn test_ctr() -> AesCtr {
+        AesCtr::new(&[0x11; 32], 0x0102_0304_0506_0708_1112_1314_1516_1718)
+    }
+
+    #[test]
+    fn pending_capacity_reclaims_after_partial_advance_without_compaction_threshold() {
+        let mut pending = PendingCiphertext::new(1024);
+        let mut ctr = test_ctr();
+        let payload = vec![0x41; 900];
+        pending.push_encrypted(&mut ctr, &payload).unwrap();
+
+        // Keep position below compaction threshold to validate logical-capacity accounting.
+        pending.advance(800);
+        assert_eq!(pending.pending_len(), 100);
+        assert_eq!(pending.remaining_capacity(), 924);
+    }
+
+    #[test]
+    fn push_encrypted_respects_pending_limit() {
+        let mut pending = PendingCiphertext::new(64);
+        let mut ctr = test_ctr();
+
+        pending.push_encrypted(&mut ctr, &[0x10; 64]).unwrap();
+        let err = pending.push_encrypted(&mut ctr, &[0x20]).unwrap_err();
+        assert_eq!(err.kind(), ErrorKind::WouldBlock);
+    }
+
+    #[test]
+    fn push_encrypted_compacts_prefix_when_physical_buffer_would_overflow() {
+        let mut pending = PendingCiphertext::new(64);
+        let mut ctr = test_ctr();
+
+        pending.push_encrypted(&mut ctr, &[0x22; 60]).unwrap();
+        pending.advance(30);
+        pending.push_encrypted(&mut ctr, &[0x33; 30]).unwrap();
+
+        assert_eq!(pending.pending_len(), 60);
+        assert!(pending.buf.len() <= 64);
+    }
+
+    #[test]
+    fn pending_ciphertext_preserves_stream_order_across_drain_and_append() {
+        let mut pending = PendingCiphertext::new(128);
+        let mut ctr = test_ctr();
+
+        let first = vec![0xA1; 80];
+        let second = vec![0xB2; 40];
+
+        pending.push_encrypted(&mut ctr, &first).unwrap();
+        pending.advance(50);
+        pending.push_encrypted(&mut ctr, &second).unwrap();
+
+        let mut baseline_ctr = test_ctr();
+        let mut baseline_plain = Vec::with_capacity(first.len() + second.len());
+        baseline_plain.extend_from_slice(&first);
+        baseline_plain.extend_from_slice(&second);
+        baseline_ctr.apply(&mut baseline_plain);
+
+        let expected = &baseline_plain[50..];
+        assert_eq!(pending.pending_slice(), expected);
+    }
+}

src/stream/frame.rs

@@ -3,6 +3,8 @@
 //! This module defines the common types and traits used by all
 //! frame encoding/decoding implementations.
 
+#![allow(dead_code)]
+
 use bytes::{Bytes, BytesMut};
 use std::io::Result;
 use std::sync::Arc;

src/stream/frame_codec.rs

@@ -3,12 +3,16 @@
 //! This module provides Encoder/Decoder implementations compatible
 //! with tokio-util's Framed wrapper for easy async frame I/O.
 
+#![allow(dead_code)]
+
 use bytes::{Bytes, BytesMut, BufMut};
 use std::io::{self, Error, ErrorKind};
 use std::sync::Arc;
 use tokio_util::codec::{Decoder, Encoder};
 
-use crate::protocol::constants::ProtoTag;
+use crate::protocol::constants::{
+    ProtoTag, is_valid_secure_payload_len, secure_padding_len, secure_payload_len_from_wire_len,
+};
 use crate::crypto::SecureRandom;
 use super::frame::{Frame, FrameMeta, FrameCodec as FrameCodecTrait};
 
@@ -135,7 +139,7 @@ fn encode_abridged(frame: &Frame, dst: &mut BytesMut) -> io::Result<()> {
     let data = &frame.data;
     
     // Validate alignment
-    if data.len() % 4 != 0 {
+    if !data.len().is_multiple_of(4) {
         return Err(Error::new(
             ErrorKind::InvalidInput,
             format!("abridged frame must be 4-byte aligned, got {} bytes", data.len())
@@ -274,13 +278,13 @@ fn decode_secure(src: &mut BytesMut, max_size: usize) -> io::Result<Option<Frame
         return Ok(None);
     }
     
-    // Calculate padding (indicated by length not divisible by 4)
-    let padding_len = len % 4;
-    let data_len = if padding_len != 0 {
-        len - padding_len
-    } else {
-        len
-    };
+    let data_len = secure_payload_len_from_wire_len(len).ok_or_else(|| {
+        Error::new(
+            ErrorKind::InvalidData,
+            format!("invalid secure frame length: {len}"),
+        )
+    })?;
+    let padding_len = len - data_len;
     
     meta.padding_len = padding_len as u8;
     
@@ -303,14 +307,15 @@ fn encode_secure(frame: &Frame, dst: &mut BytesMut, rng: &SecureRandom) -> io::R
         return Ok(());
     }
     
-    // Generate padding to make length not divisible by 4
-    let padding_len = if data.len() % 4 == 0 {
-        // Add 1-3 bytes to make it non-aligned
-        (rng.range(3) + 1) as usize
-    } else {
-        // Already non-aligned, can add 0-3
-        rng.range(4) as usize
-    };
+    if !is_valid_secure_payload_len(data.len()) {
+        return Err(Error::new(
+            ErrorKind::InvalidData,
+            format!("secure payload must be 4-byte aligned, got {}", data.len()),
+        ));
+    }
+
+    // Generate padding that keeps total length non-divisible by 4.
+    let padding_len = secure_padding_len(data.len(), rng);
     
     let total_len = data.len() + padding_len;
     dst.reserve(4 + total_len);
@@ -625,4 +630,4 @@ mod tests {
         let result = codec.decode(&mut buf);
         assert!(result.is_err());
     }
-}
+}

src/stream/frame_stream.rs

@@ -1,6 +1,8 @@
 //! MTProto frame stream wrappers
 
-use bytes::{Bytes, BytesMut};
+#![allow(dead_code)]
+
+use bytes::Bytes;
 use std::io::{Error, ErrorKind, Result};
 use tokio::io::{AsyncRead, AsyncWrite, AsyncReadExt, AsyncWriteExt};
 use crate::protocol::constants::*;
@@ -76,7 +78,7 @@ impl<W> AbridgedFrameWriter<W> {
 impl<W: AsyncWrite + Unpin> AbridgedFrameWriter<W> {
     /// Write a frame
     pub async fn write_frame(&mut self, data: &[u8], meta: &FrameMeta) -> Result<()> {
-        if data.len() % 4 != 0 {
+        if !data.len().is_multiple_of(4) {
             return Err(Error::new(
                 ErrorKind::InvalidInput,
                 format!("Abridged frame must be aligned to 4 bytes, got {}", data.len()),
@@ -232,11 +234,13 @@ impl<R: AsyncRead + Unpin> SecureIntermediateFrameReader<R> {
         let mut data = vec![0u8; len];
         self.upstream.read_exact(&mut data).await?;
         
-        // Strip padding (not aligned to 4)
-        if len % 4 != 0 {
-            let actual_len = len - (len % 4);
-            data.truncate(actual_len);
-        }
+        let payload_len = secure_payload_len_from_wire_len(len).ok_or_else(|| {
+            Error::new(
+                ErrorKind::InvalidData,
+                format!("Invalid secure frame length: {len}"),
+            )
+        })?;
+        data.truncate(payload_len);
         
         Ok((Bytes::from(data), meta))
     }
@@ -267,8 +271,15 @@ impl<W: AsyncWrite + Unpin> SecureIntermediateFrameWriter<W> {
             return Ok(());
         }
         
-        // Add random padding (0-3 bytes)
-        let padding_len = self.rng.range(4);
+        if !is_valid_secure_payload_len(data.len()) {
+            return Err(Error::new(
+                ErrorKind::InvalidData,
+                format!("Secure payload must be 4-byte aligned, got {}", data.len()),
+            ));
+        }
+
+        // Add padding so total length is never divisible by 4 (MTProto Secure)
+        let padding_len = secure_padding_len(data.len(), &self.rng);
         let padding = self.rng.bytes(padding_len);
         
         let total_len = data.len() + padding_len;
@@ -320,7 +331,7 @@ impl<R: AsyncRead + Unpin> MtprotoFrameReader<R> {
             }
             
             // Validate length
-            if len < MIN_MSG_LEN || len > MAX_MSG_LEN || len % PADDING_FILLER.len() != 0 {
+            if !(MIN_MSG_LEN..=MAX_MSG_LEN).contains(&len) || !len.is_multiple_of(PADDING_FILLER.len()) {
                 return Err(Error::new(
                     ErrorKind::InvalidData,
                     format!("Invalid message length: {}", len),
@@ -550,9 +561,7 @@ mod tests {
         writer.flush().await.unwrap();
         
         let (received, _meta) = reader.read_frame().await.unwrap();
-        // Received should have padding stripped to align to 4
-        let expected_len = (data.len() / 4) * 4;
-        assert_eq!(received.len(), expected_len);
+        assert_eq!(received.len(), data.len());
     }
     
     #[tokio::test]
@@ -585,4 +594,4 @@ mod tests {
         let (received, _) = reader.read_frame().await.unwrap();
         assert_eq!(&received[..], &data[..]);
     }
-}
+}

src/stream/mod.rs

@@ -12,32 +12,38 @@ pub mod frame_codec;
 pub mod frame_stream;
 
 // Re-export state machine types
+#[allow(unused_imports)]
 pub use state::{
     StreamState, Transition, PollResult,
     ReadBuffer, WriteBuffer, HeaderBuffer, YieldBuffer,
 };
 
 // Re-export buffer pool
+#[allow(unused_imports)]
 pub use buffer_pool::{BufferPool, PooledBuffer, PoolStats};
 
 // Re-export stream implementations
+#[allow(unused_imports)]
 pub use crypto_stream::{CryptoReader, CryptoWriter, PassthroughStream};
 pub use tls_stream::{FakeTlsReader, FakeTlsWriter};
 
 // Re-export frame types
+#[allow(unused_imports)]
 pub use frame::{Frame, FrameMeta, FrameCodec as FrameCodecTrait, create_codec};
 
-// Re-export tokio-util compatible codecs  
+// Re-export tokio-util compatible codecs
+#[allow(unused_imports)]
 pub use frame_codec::{
     FrameCodec,
     AbridgedCodec, IntermediateCodec, SecureCodec,
 };
 
 // Legacy re-exports for compatibility
+#[allow(unused_imports)]
 pub use frame_stream::{
     AbridgedFrameReader, AbridgedFrameWriter,
     IntermediateFrameReader, IntermediateFrameWriter,
     SecureIntermediateFrameReader, SecureIntermediateFrameWriter,
     MtprotoFrameReader, MtprotoFrameWriter,
     FrameReaderKind, FrameWriterKind,
-};
+};

src/stream/state.rs

@@ -3,6 +3,8 @@
 //! This module provides core types and traits for implementing
 //! stateful async streams with proper partial read/write handling.
 
+#![allow(dead_code)]
+
 use bytes::{Bytes, BytesMut};
 use std::io;
 

src/stream/tls_stream.rs

@@ -18,6 +18,8 @@
 //! - Explicit state machines for all async operations
 //! - Never lose data on partial reads
 //! - Atomic TLS record formation for writes
+
+#![allow(dead_code)]
 //! - Proper handling of all TLS record types
 //!
 //! Important nuance (Telegram FakeTLS):
@@ -25,7 +27,8 @@
 //! - However, the on-the-wire record length can exceed 16384 because TLS 1.3
 //!   uses AEAD and can include tag/overhead/padding.
 //! - Telegram FakeTLS clients (notably iOS) may send Application Data records
-//!   with length up to 16384 + 24 bytes. We accept that as MAX_TLS_CHUNK_SIZE.
+//!   with length up to 16384 + 256 bytes (RFC 8446 §5.2). We accept that as
+//!   MAX_TLS_CHUNK_SIZE.
 //!
 //! If you reject those (e.g. validate length <= 16384), you will see errors like:
 //!   "TLS record too large: 16408 bytes"
@@ -52,9 +55,8 @@ use super::state::{StreamState, HeaderBuffer, YieldBuffer, WriteBuffer};
 const TLS_HEADER_SIZE: usize = 5;
 
 /// Maximum TLS fragment size we emit for Application Data.
-/// Real TLS 1.3 ciphertexts often add ~16-24 bytes AEAD overhead, so to mimic
-/// on-the-wire record sizes we allow up to 16384 + 24 bytes of plaintext.
-const MAX_TLS_PAYLOAD: usize = 16384 + 24;
+/// Real TLS 1.3 allows up to 16384 + 256 bytes of ciphertext (incl. tag).
+const MAX_TLS_PAYLOAD: usize = 16384 + 256;
 
 /// Maximum pending write buffer for one record remainder.
 /// Note: we never queue unlimited amount of data here; state holds at most one record.
@@ -91,7 +93,7 @@ impl TlsRecordHeader {
     /// - We accept TLS 1.0 header version for ClientHello-like records (0x03 0x01),
     ///   and TLS 1.2/1.3 style version bytes for the rest (we use TLS_VERSION = 0x03 0x03).
     /// - For Application Data, Telegram FakeTLS may send payload length up to
-    ///   MAX_TLS_CHUNK_SIZE (16384 + 24).
+    ///   MAX_TLS_CHUNK_SIZE (16384 + 256).
     /// - For other record types we keep stricter bounds to avoid memory abuse.
     fn validate(&self) -> Result<()> {
         // Version: accept TLS 1.0 header (ClientHello quirk) and TLS_VERSION (0x0303).
@@ -105,7 +107,7 @@ impl TlsRecordHeader {
         let len = self.length as usize;
 
         // Length checks depend on record type.
-        // Telegram FakeTLS: ApplicationData length may be 16384 + 24.
+        // Telegram FakeTLS: ApplicationData length may be 16384 + 256.
         match self.record_type {
             TLS_RECORD_APPLICATION => {
                 if len > MAX_TLS_CHUNK_SIZE {
@@ -133,7 +135,7 @@ impl TlsRecordHeader {
     }
 
     /// Build header bytes
-    fn to_bytes(&self) -> [u8; 5] {
+    fn to_bytes(self) -> [u8; 5] {
         [
             self.record_type,
             self.version[0],
@@ -258,9 +260,9 @@ impl<R> FakeTlsReader<R> {
     fn take_poison_error(&mut self) -> io::Error {
         match &mut self.state {
             TlsReaderState::Poisoned { error } => error.take().unwrap_or_else(|| {
-                io::Error::new(ErrorKind::Other, "stream previously poisoned")
+                io::Error::other("stream previously poisoned")
             }),
-            _ => io::Error::new(ErrorKind::Other, "stream not poisoned"),
+            _ => io::Error::other("stream not poisoned"),
         }
     }
 }
@@ -295,7 +297,7 @@ impl<R: AsyncRead + Unpin> AsyncRead for FakeTlsReader<R> {
                 TlsReaderState::Poisoned { error } => {
                     this.state = TlsReaderState::Poisoned { error: None };
                     let err = error.unwrap_or_else(|| {
-                        io::Error::new(ErrorKind::Other, "stream previously poisoned")
+                        io::Error::other("stream previously poisoned")
                     });
                     return Poll::Ready(Err(err));
                 }
@@ -614,9 +616,9 @@ impl<W> FakeTlsWriter<W> {
     fn take_poison_error(&mut self) -> io::Error {
         match &mut self.state {
             TlsWriterState::Poisoned { error } => error.take().unwrap_or_else(|| {
-                io::Error::new(ErrorKind::Other, "stream previously poisoned")
+                io::Error::other("stream previously poisoned")
             }),
-            _ => io::Error::new(ErrorKind::Other, "stream not poisoned"),
+            _ => io::Error::other("stream not poisoned"),
         }
     }
 
@@ -680,7 +682,7 @@ impl<W: AsyncWrite + Unpin> AsyncWrite for FakeTlsWriter<W> {
             TlsWriterState::Poisoned { error } => {
                 this.state = TlsWriterState::Poisoned { error: None };
                 let err = error.unwrap_or_else(|| {
-                    Error::new(ErrorKind::Other, "stream previously poisoned")
+                    Error::other("stream previously poisoned")
                 });
                 return Poll::Ready(Err(err));
             }
@@ -755,9 +757,6 @@ impl<W: AsyncWrite + Unpin> AsyncWrite for FakeTlsWriter<W> {
                     payload_size: chunk_size,
                 };
 
-                // Wake to retry flushing soon.
-                cx.waker().wake_by_ref();
-
                 Poll::Ready(Ok(chunk_size))
             }
         }
@@ -772,7 +771,7 @@ impl<W: AsyncWrite + Unpin> AsyncWrite for FakeTlsWriter<W> {
             TlsWriterState::Poisoned { error } => {
                 this.state = TlsWriterState::Poisoned { error: None };
                 let err = error.unwrap_or_else(|| {
-                    Error::new(ErrorKind::Other, "stream previously poisoned")
+                    Error::other("stream previously poisoned")
                 });
                 return Poll::Ready(Err(err));
             }

src/stream/traits.rs

@@ -1,5 +1,7 @@
 //! Stream traits and common types
 
+#![allow(dead_code)]
+
 use bytes::Bytes;
 use std::io::Result;
 use std::pin::Pin;

src/tls_front/cache.rs

@@ -1,7 +1,8 @@
 use std::collections::HashMap;
+use std::net::IpAddr;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
-use std::time::{SystemTime, Duration};
+use std::time::{Duration, Instant, SystemTime};
 
 use tokio::sync::RwLock;
 use tokio::time::sleep;
@@ -14,9 +15,11 @@ use crate::tls_front::types::{CachedTlsData, ParsedServerHello, TlsFetchResult};
 pub struct TlsFrontCache {
     memory: RwLock<HashMap<String, Arc<CachedTlsData>>>,
     default: Arc<CachedTlsData>,
+    full_cert_sent: RwLock<HashMap<IpAddr, Instant>>,
     disk_path: PathBuf,
 }
 
+#[allow(dead_code)]
 impl TlsFrontCache {
     pub fn new(domains: &[String], default_len: usize, disk_path: impl AsRef<Path>) -> Self {
         let default_template = ParsedServerHello {
@@ -31,6 +34,7 @@ impl TlsFrontCache {
         let default = Arc::new(CachedTlsData {
             server_hello_template: default_template,
             cert_info: None,
+            cert_payload: None,
             app_data_records_sizes: vec![default_len],
             total_app_data_len: default_len,
             fetched_at: SystemTime::now(),
@@ -45,6 +49,7 @@ impl TlsFrontCache {
         Self {
             memory: RwLock::new(map),
             default,
+            full_cert_sent: RwLock::new(HashMap::new()),
             disk_path: disk_path.as_ref().to_path_buf(),
         }
     }
@@ -54,6 +59,45 @@ impl TlsFrontCache {
         guard.get(sni).cloned().unwrap_or_else(|| self.default.clone())
     }
 
+    pub async fn contains_domain(&self, domain: &str) -> bool {
+        self.memory.read().await.contains_key(domain)
+    }
+
+    /// Returns true when full cert payload should be sent for client_ip
+    /// according to TTL policy.
+    pub async fn take_full_cert_budget_for_ip(
+        &self,
+        client_ip: IpAddr,
+        ttl: Duration,
+    ) -> bool {
+        if ttl.is_zero() {
+            self.full_cert_sent
+                .write()
+                .await
+                .insert(client_ip, Instant::now());
+            return true;
+        }
+
+        let now = Instant::now();
+        let mut guard = self.full_cert_sent.write().await;
+        guard.retain(|_, seen_at| now.duration_since(*seen_at) < ttl);
+
+        match guard.get_mut(&client_ip) {
+            Some(seen_at) => {
+                if now.duration_since(*seen_at) >= ttl {
+                    *seen_at = now;
+                    true
+                } else {
+                    false
+                }
+            }
+            None => {
+                guard.insert(client_ip, now);
+                true
+            }
+        }
+    }
+
     pub async fn set(&self, domain: &str, data: CachedTlsData) {
         let mut guard = self.memory.write().await;
         guard.insert(domain.to_string(), Arc::new(data));
@@ -71,12 +115,32 @@ impl TlsFrontCache {
                     if !name.ends_with(".json") {
                         continue;
                     }
-                    if let Ok(data) = tokio::fs::read(entry.path()).await {
-                        if let Ok(cached) = serde_json::from_slice::<CachedTlsData>(&data) {
-                            let domain = cached.domain.clone();
-                            self.set(&domain, cached).await;
-                            loaded += 1;
+                    if let Ok(data) = tokio::fs::read(entry.path()).await
+                        && let Ok(mut cached) = serde_json::from_slice::<CachedTlsData>(&data)
+                    {
+                        if cached.domain.is_empty()
+                            || cached.domain.len() > 255
+                            || !cached.domain.chars().all(|c| c.is_ascii_alphanumeric() || c == '.' || c == '-')
+                        {
+                            warn!(file = %name, "Skipping TLS cache entry with invalid domain");
+                            continue;
                         }
+                        // fetched_at is skipped during deserialization; approximate with file mtime if available.
+                        if let Ok(meta) = entry.metadata().await
+                            && let Ok(modified) = meta.modified()
+                        {
+                            cached.fetched_at = modified;
+                        }
+                        // Drop entries older than 72h
+                        if let Ok(age) = cached.fetched_at.elapsed()
+                            && age > Duration::from_secs(72 * 3600)
+                        {
+                            warn!(domain = %cached.domain, "Skipping stale TLS cache entry (>72h)");
+                            continue;
+                        }
+                        let domain = cached.domain.clone();
+                        self.set(&domain, cached).await;
+                        loaded += 1;
                     }
                 }
             }
@@ -110,7 +174,7 @@ impl TlsFrontCache {
         tokio::spawn(async move {
             loop {
                 for domain in &domains {
-                    fetcher(domain.clone()).await;
+                    let _ = fetcher(domain.clone()).await;
                 }
                 sleep(interval).await;
             }
@@ -122,6 +186,7 @@ impl TlsFrontCache {
         let data = CachedTlsData {
             server_hello_template: fetched.server_hello_parsed,
             cert_info: fetched.cert_info,
+            cert_payload: fetched.cert_payload,
             app_data_records_sizes: fetched.app_data_records_sizes.clone(),
             total_app_data_len: fetched.total_app_data_len,
             fetched_at: SystemTime::now(),
@@ -141,3 +206,50 @@ impl TlsFrontCache {
         &self.disk_path
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[tokio::test]
+    async fn test_take_full_cert_budget_for_ip_uses_ttl() {
+        let cache = TlsFrontCache::new(
+            &["example.com".to_string()],
+            1024,
+            "tlsfront-test-cache",
+        );
+        let ip: IpAddr = "127.0.0.1".parse().expect("ip");
+        let ttl = Duration::from_millis(80);
+
+        assert!(cache
+            .take_full_cert_budget_for_ip(ip, ttl)
+            .await);
+        assert!(!cache
+            .take_full_cert_budget_for_ip(ip, ttl)
+            .await);
+
+        tokio::time::sleep(Duration::from_millis(90)).await;
+
+        assert!(cache
+            .take_full_cert_budget_for_ip(ip, ttl)
+            .await);
+    }
+
+    #[tokio::test]
+    async fn test_take_full_cert_budget_for_ip_zero_ttl_always_allows_full_payload() {
+        let cache = TlsFrontCache::new(
+            &["example.com".to_string()],
+            1024,
+            "tlsfront-test-cache",
+        );
+        let ip: IpAddr = "127.0.0.1".parse().expect("ip");
+        let ttl = Duration::ZERO;
+
+        assert!(cache
+            .take_full_cert_budget_for_ip(ip, ttl)
+            .await);
+        assert!(cache
+            .take_full_cert_budget_for_ip(ip, ttl)
+            .await);
+    }
+}

src/tls_front/emulator.rs

@@ -3,7 +3,7 @@ use crate::protocol::constants::{
     TLS_RECORD_APPLICATION, TLS_RECORD_CHANGE_CIPHER, TLS_RECORD_HANDSHAKE, TLS_VERSION,
 };
 use crate::protocol::tls::{TLS_DIGEST_LEN, TLS_DIGEST_POS, gen_fake_x25519_key};
-use crate::tls_front::types::CachedTlsData;
+use crate::tls_front::types::{CachedTlsData, ParsedCertificateInfo};
 
 const MIN_APP_DATA: usize = 64;
 const MAX_APP_DATA: usize = 16640; // RFC 8446 §5.2 allows up to 2^14 + 256
@@ -12,7 +12,7 @@ fn jitter_and_clamp_sizes(sizes: &[usize], rng: &SecureRandom) -> Vec<usize> {
     sizes
         .iter()
         .map(|&size| {
-            let base = size.max(MIN_APP_DATA).min(MAX_APP_DATA);
+            let base = size.clamp(MIN_APP_DATA, MAX_APP_DATA);
             let jitter_range = ((base as f64) * 0.03).round() as i64;
             if jitter_range == 0 {
                 return base;
@@ -27,13 +27,84 @@ fn jitter_and_clamp_sizes(sizes: &[usize], rng: &SecureRandom) -> Vec<usize> {
         .collect()
 }
 
+fn app_data_body_capacity(sizes: &[usize]) -> usize {
+    sizes.iter().map(|&size| size.saturating_sub(17)).sum()
+}
+
+fn ensure_payload_capacity(mut sizes: Vec<usize>, payload_len: usize) -> Vec<usize> {
+    if payload_len == 0 {
+        return sizes;
+    }
+
+    let mut body_total = app_data_body_capacity(&sizes);
+    if body_total >= payload_len {
+        return sizes;
+    }
+
+    if let Some(last) = sizes.last_mut() {
+        let free = MAX_APP_DATA.saturating_sub(*last);
+        let grow = free.min(payload_len - body_total);
+        *last += grow;
+        body_total += grow;
+    }
+
+    while body_total < payload_len {
+        let remaining = payload_len - body_total;
+        let chunk = (remaining + 17).clamp(MIN_APP_DATA, MAX_APP_DATA);
+        sizes.push(chunk);
+        body_total += chunk.saturating_sub(17);
+    }
+
+    sizes
+}
+
+fn build_compact_cert_info_payload(cert_info: &ParsedCertificateInfo) -> Option<Vec<u8>> {
+    let mut fields = Vec::new();
+
+    if let Some(subject) = cert_info.subject_cn.as_deref() {
+        fields.push(format!("CN={subject}"));
+    }
+    if let Some(issuer) = cert_info.issuer_cn.as_deref() {
+        fields.push(format!("ISSUER={issuer}"));
+    }
+    if let Some(not_before) = cert_info.not_before_unix {
+        fields.push(format!("NB={not_before}"));
+    }
+    if let Some(not_after) = cert_info.not_after_unix {
+        fields.push(format!("NA={not_after}"));
+    }
+    if !cert_info.san_names.is_empty() {
+        let san = cert_info
+            .san_names
+            .iter()
+            .take(8)
+            .map(String::as_str)
+            .collect::<Vec<_>>()
+            .join(",");
+        fields.push(format!("SAN={san}"));
+    }
+
+    if fields.is_empty() {
+        return None;
+    }
+
+    let mut payload = fields.join(";").into_bytes();
+    if payload.len() > 512 {
+        payload.truncate(512);
+    }
+    Some(payload)
+}
+
 /// Build a ServerHello + CCS + ApplicationData sequence using cached TLS metadata.
 pub fn build_emulated_server_hello(
     secret: &[u8],
     client_digest: &[u8; TLS_DIGEST_LEN],
     session_id: &[u8],
     cached: &CachedTlsData,
+    use_full_cert_payload: bool,
     rng: &SecureRandom,
+    alpn: Option<Vec<u8>>,
+    new_session_tickets: u8,
 ) -> Vec<u8> {
     // --- ServerHello ---
     let mut extensions = Vec::new();
@@ -48,6 +119,15 @@ pub fn build_emulated_server_hello(
     extensions.extend_from_slice(&0x002bu16.to_be_bytes());
     extensions.extend_from_slice(&(2u16).to_be_bytes());
     extensions.extend_from_slice(&0x0304u16.to_be_bytes());
+    if let Some(alpn_proto) = &alpn {
+        extensions.extend_from_slice(&0x0010u16.to_be_bytes());
+        let list_len: u16 = 1 + alpn_proto.len() as u16;
+        let ext_len: u16 = 2 + list_len;
+        extensions.extend_from_slice(&ext_len.to_be_bytes());
+        extensions.extend_from_slice(&list_len.to_be_bytes());
+        extensions.push(alpn_proto.len() as u8);
+        extensions.extend_from_slice(alpn_proto);
+    }
 
     let extensions_len = extensions.len() as u16;
 
@@ -98,15 +178,52 @@ pub fn build_emulated_server_hello(
     if sizes.is_empty() {
         sizes.push(cached.total_app_data_len.max(1024));
     }
-    let sizes = jitter_and_clamp_sizes(&sizes, rng);
+    let mut sizes = jitter_and_clamp_sizes(&sizes, rng);
+    let compact_payload = cached
+        .cert_info
+        .as_ref()
+        .and_then(build_compact_cert_info_payload);
+    let selected_payload: Option<&[u8]> = if use_full_cert_payload {
+        cached
+            .cert_payload
+            .as_ref()
+            .map(|payload| payload.certificate_message.as_slice())
+            .filter(|payload| !payload.is_empty())
+            .or(compact_payload.as_deref())
+    } else {
+        compact_payload.as_deref()
+    };
+
+    if let Some(payload) = selected_payload {
+        sizes = ensure_payload_capacity(sizes, payload.len());
+    }
 
     let mut app_data = Vec::new();
+    let mut payload_offset = 0usize;
     for size in sizes {
         let mut rec = Vec::with_capacity(5 + size);
         rec.push(TLS_RECORD_APPLICATION);
         rec.extend_from_slice(&TLS_VERSION);
         rec.extend_from_slice(&(size as u16).to_be_bytes());
-        if size > 17 {
+
+        if let Some(payload) = selected_payload {
+            if size > 17 {
+                let body_len = size - 17;
+                let remaining = payload.len().saturating_sub(payload_offset);
+                let copy_len = remaining.min(body_len);
+                if copy_len > 0 {
+                    rec.extend_from_slice(&payload[payload_offset..payload_offset + copy_len]);
+                    payload_offset += copy_len;
+                }
+                if body_len > copy_len {
+                    rec.extend_from_slice(&rng.bytes(body_len - copy_len));
+                }
+                rec.push(0x16); // inner content type marker (handshake)
+                rec.extend_from_slice(&rng.bytes(16)); // AEAD-like tag
+            } else {
+                rec.extend_from_slice(&rng.bytes(size));
+            }
+        } else if size > 17 {
             let body_len = size - 17;
             rec.extend_from_slice(&rng.bytes(body_len));
             rec.push(0x16); // inner content type marker (handshake)
@@ -118,10 +235,25 @@ pub fn build_emulated_server_hello(
     }
 
     // --- Combine ---
-    let mut response = Vec::with_capacity(server_hello.len() + change_cipher_spec.len() + app_data.len());
+    // Optional NewSessionTicket mimic records (opaque ApplicationData for fingerprint).
+    let mut tickets = Vec::new();
+    if new_session_tickets > 0 {
+        for _ in 0..new_session_tickets {
+            let ticket_len: usize = rng.range(48) + 48;
+            let mut rec = Vec::with_capacity(5 + ticket_len);
+            rec.push(TLS_RECORD_APPLICATION);
+            rec.extend_from_slice(&TLS_VERSION);
+            rec.extend_from_slice(&(ticket_len as u16).to_be_bytes());
+            rec.extend_from_slice(&rng.bytes(ticket_len));
+            tickets.extend_from_slice(&rec);
+        }
+    }
+
+    let mut response = Vec::with_capacity(server_hello.len() + change_cipher_spec.len() + app_data.len() + tickets.len());
     response.extend_from_slice(&server_hello);
     response.extend_from_slice(&change_cipher_spec);
     response.extend_from_slice(&app_data);
+    response.extend_from_slice(&tickets);
 
     // --- HMAC ---
     let mut hmac_input = Vec::with_capacity(TLS_DIGEST_LEN + response.len());
@@ -132,3 +264,125 @@ pub fn build_emulated_server_hello(
 
     response
 }
+
+#[cfg(test)]
+mod tests {
+    use std::time::SystemTime;
+
+    use crate::tls_front::types::{CachedTlsData, ParsedServerHello, TlsCertPayload};
+
+    use super::build_emulated_server_hello;
+    use crate::crypto::SecureRandom;
+    use crate::protocol::constants::{
+        TLS_RECORD_APPLICATION, TLS_RECORD_CHANGE_CIPHER, TLS_RECORD_HANDSHAKE,
+    };
+
+    fn first_app_data_payload(response: &[u8]) -> &[u8] {
+        let hello_len = u16::from_be_bytes([response[3], response[4]]) as usize;
+        let ccs_start = 5 + hello_len;
+        let ccs_len = u16::from_be_bytes([response[ccs_start + 3], response[ccs_start + 4]]) as usize;
+        let app_start = ccs_start + 5 + ccs_len;
+        let app_len = u16::from_be_bytes([response[app_start + 3], response[app_start + 4]]) as usize;
+        &response[app_start + 5..app_start + 5 + app_len]
+    }
+
+    fn make_cached(cert_payload: Option<TlsCertPayload>) -> CachedTlsData {
+        CachedTlsData {
+            server_hello_template: ParsedServerHello {
+                version: [0x03, 0x03],
+                random: [0u8; 32],
+                session_id: Vec::new(),
+                cipher_suite: [0x13, 0x01],
+                compression: 0,
+                extensions: Vec::new(),
+            },
+            cert_info: None,
+            cert_payload,
+            app_data_records_sizes: vec![64],
+            total_app_data_len: 64,
+            fetched_at: SystemTime::now(),
+            domain: "example.com".to_string(),
+        }
+    }
+
+    #[test]
+    fn test_build_emulated_server_hello_uses_cached_cert_payload() {
+        let cert_msg = vec![0x0b, 0x00, 0x00, 0x05, 0x00, 0xaa, 0xbb, 0xcc, 0xdd];
+        let cached = make_cached(Some(TlsCertPayload {
+            cert_chain_der: vec![vec![0x30, 0x01, 0x00]],
+            certificate_message: cert_msg.clone(),
+        }));
+        let rng = SecureRandom::new();
+        let response = build_emulated_server_hello(
+            b"secret",
+            &[0x11; 32],
+            &[0x22; 16],
+            &cached,
+            true,
+            &rng,
+            None,
+            0,
+        );
+
+        assert_eq!(response[0], TLS_RECORD_HANDSHAKE);
+        let hello_len = u16::from_be_bytes([response[3], response[4]]) as usize;
+        let ccs_start = 5 + hello_len;
+        assert_eq!(response[ccs_start], TLS_RECORD_CHANGE_CIPHER);
+        let app_start = ccs_start + 6;
+        assert_eq!(response[app_start], TLS_RECORD_APPLICATION);
+
+        let payload = first_app_data_payload(&response);
+        assert!(payload.starts_with(&cert_msg));
+    }
+
+    #[test]
+    fn test_build_emulated_server_hello_random_fallback_when_no_cert_payload() {
+        let cached = make_cached(None);
+        let rng = SecureRandom::new();
+        let response = build_emulated_server_hello(
+            b"secret",
+            &[0x22; 32],
+            &[0x33; 16],
+            &cached,
+            true,
+            &rng,
+            None,
+            0,
+        );
+
+        let payload = first_app_data_payload(&response);
+        assert!(payload.len() >= 64);
+        assert_eq!(payload[payload.len() - 17], 0x16);
+    }
+
+    #[test]
+    fn test_build_emulated_server_hello_uses_compact_payload_after_first() {
+        let cert_msg = vec![0x0b, 0x00, 0x00, 0x05, 0x00, 0xaa, 0xbb, 0xcc, 0xdd];
+        let mut cached = make_cached(Some(TlsCertPayload {
+            cert_chain_der: vec![vec![0x30, 0x01, 0x00]],
+            certificate_message: cert_msg,
+        }));
+        cached.cert_info = Some(crate::tls_front::types::ParsedCertificateInfo {
+            not_after_unix: Some(1_900_000_000),
+            not_before_unix: Some(1_700_000_000),
+            issuer_cn: Some("Issuer".to_string()),
+            subject_cn: Some("example.com".to_string()),
+            san_names: vec!["example.com".to_string(), "www.example.com".to_string()],
+        });
+
+        let rng = SecureRandom::new();
+        let response = build_emulated_server_hello(
+            b"secret",
+            &[0x44; 32],
+            &[0x55; 16],
+            &cached,
+            false,
+            &rng,
+            None,
+            0,
+        );
+
+        let payload = first_app_data_payload(&response);
+        assert!(payload.starts_with(b"CN=example.com"));
+    }
+}

src/tls_front/fetcher.rs

@@ -1,9 +1,11 @@
 use std::sync::Arc;
 use std::time::Duration;
 
-use anyhow::{Context, Result, anyhow};
-use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use anyhow::{Result, anyhow};
+use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
 use tokio::net::TcpStream;
+#[cfg(unix)]
+use tokio::net::UnixStream;
 use tokio::time::timeout;
 use tokio_rustls::client::TlsStream;
 use tokio_rustls::TlsConnector;
@@ -18,8 +20,16 @@ use x509_parser::prelude::FromDer;
 use x509_parser::certificate::X509Certificate;
 
 use crate::crypto::SecureRandom;
+use crate::network::dns_overrides::resolve_socket_addr;
 use crate::protocol::constants::{TLS_RECORD_APPLICATION, TLS_RECORD_HANDSHAKE};
-use crate::tls_front::types::{ParsedServerHello, TlsExtension, TlsFetchResult, ParsedCertificateInfo};
+use crate::transport::proxy_protocol::{ProxyProtocolV1Builder, ProxyProtocolV2Builder};
+use crate::tls_front::types::{
+    ParsedCertificateInfo,
+    ParsedServerHello,
+    TlsCertPayload,
+    TlsExtension,
+    TlsFetchResult,
+};
 
 /// No-op verifier: accept any certificate (we only need lengths and metadata).
 #[derive(Debug)]
@@ -204,7 +214,10 @@ fn gen_key_share(rng: &SecureRandom) -> [u8; 32] {
     key
 }
 
-async fn read_tls_record(stream: &mut TcpStream) -> Result<(u8, Vec<u8>)> {
+async fn read_tls_record<S>(stream: &mut S) -> Result<(u8, Vec<u8>)>
+where
+    S: AsyncRead + Unpin,
+{
     let mut header = [0u8; 5];
     stream.read_exact(&mut header).await?;
     let len = u16::from_be_bytes([header[3], header[4]]) as usize;
@@ -315,18 +328,114 @@ fn parse_cert_info(certs: &[CertificateDer<'static>]) -> Option<ParsedCertificat
     })
 }
 
-async fn fetch_via_raw_tls(
+fn u24_bytes(value: usize) -> Option<[u8; 3]> {
+    if value > 0x00ff_ffff {
+        return None;
+    }
+    Some([
+        ((value >> 16) & 0xff) as u8,
+        ((value >> 8) & 0xff) as u8,
+        (value & 0xff) as u8,
+    ])
+}
+
+async fn connect_with_dns_override(
     host: &str,
     port: u16,
+    connect_timeout: Duration,
+) -> Result<TcpStream> {
+    if let Some(addr) = resolve_socket_addr(host, port) {
+        return Ok(timeout(connect_timeout, TcpStream::connect(addr)).await??);
+    }
+    Ok(timeout(connect_timeout, TcpStream::connect((host, port))).await??)
+}
+
+async fn connect_tcp_with_upstream(
+    host: &str,
+    port: u16,
+    connect_timeout: Duration,
+    upstream: Option<std::sync::Arc<crate::transport::UpstreamManager>>,
+) -> Result<TcpStream> {
+    if let Some(manager) = upstream {
+        if let Some(addr) = resolve_socket_addr(host, port) {
+            match manager.connect(addr, None, None).await {
+                Ok(stream) => return Ok(stream),
+                Err(e) => {
+                    warn!(
+                        host = %host,
+                        port = port,
+                        error = %e,
+                        "Upstream connect failed, using direct connect"
+                    );
+                }
+            }
+        } else if let Ok(mut addrs) = tokio::net::lookup_host((host, port)).await {
+            if let Some(addr) = addrs.find(|a| a.is_ipv4()) {
+                match manager.connect(addr, None, None).await {
+                    Ok(stream) => return Ok(stream),
+                    Err(e) => {
+                        warn!(
+                            host = %host,
+                            port = port,
+                            error = %e,
+                            "Upstream connect failed, using direct connect"
+                        );
+                    }
+                }
+            }
+        }
+    }
+    connect_with_dns_override(host, port, connect_timeout).await
+}
+
+fn encode_tls13_certificate_message(cert_chain_der: &[Vec<u8>]) -> Option<Vec<u8>> {
+    if cert_chain_der.is_empty() {
+        return None;
+    }
+
+    let mut certificate_list = Vec::new();
+    for cert in cert_chain_der {
+        if cert.is_empty() {
+            return None;
+        }
+        certificate_list.extend_from_slice(&u24_bytes(cert.len())?);
+        certificate_list.extend_from_slice(cert);
+        certificate_list.extend_from_slice(&0u16.to_be_bytes()); // cert_entry extensions
+    }
+
+    // Certificate = context_len(1) + certificate_list_len(3) + entries
+    let body_len = 1usize
+        .checked_add(3)?
+        .checked_add(certificate_list.len())?;
+
+    let mut message = Vec::with_capacity(4 + body_len);
+    message.push(0x0b); // HandshakeType::certificate
+    message.extend_from_slice(&u24_bytes(body_len)?);
+    message.push(0x00); // certificate_request_context length
+    message.extend_from_slice(&u24_bytes(certificate_list.len())?);
+    message.extend_from_slice(&certificate_list);
+    Some(message)
+}
+
+async fn fetch_via_raw_tls_stream<S>(
+    mut stream: S,
     sni: &str,
     connect_timeout: Duration,
-) -> Result<TlsFetchResult> {
-    let addr = format!("{host}:{port}");
-    let mut stream = timeout(connect_timeout, TcpStream::connect(addr)).await??;
-
+    proxy_protocol: u8,
+) -> Result<TlsFetchResult>
+where
+    S: AsyncRead + AsyncWrite + Unpin,
+{
     let rng = SecureRandom::new();
     let client_hello = build_client_hello(sni, &rng);
     timeout(connect_timeout, async {
+        if proxy_protocol > 0 {
+            let header = match proxy_protocol {
+                2 => ProxyProtocolV2Builder::new().build(),
+                _ => ProxyProtocolV1Builder::new().build(),
+            };
+            stream.write_all(&header).await?;
+        }
         stream.write_all(&client_hello).await?;
         stream.flush().await?;
         Ok::<(), std::io::Error>(())
@@ -338,7 +447,7 @@ async fn fetch_via_raw_tls(
     for _ in 0..4 {
         match timeout(connect_timeout, read_tls_record(&mut stream)).await {
             Ok(Ok(rec)) => records.push(rec),
-            Ok(Err(e)) => return Err(e.into()),
+            Ok(Err(e)) => return Err(e),
             Err(_) => break,
         }
         if records.len() >= 3 && records.iter().any(|(t, _)| *t == TLS_RECORD_APPLICATION) {
@@ -368,46 +477,73 @@ async fn fetch_via_raw_tls(
         },
         total_app_data_len,
         cert_info: None,
+        cert_payload: None,
     })
 }
 
-/// Fetch real TLS metadata for the given SNI: negotiated cipher and cert lengths.
-pub async fn fetch_real_tls(
+async fn fetch_via_raw_tls(
     host: &str,
     port: u16,
     sni: &str,
     connect_timeout: Duration,
     upstream: Option<std::sync::Arc<crate::transport::UpstreamManager>>,
+    proxy_protocol: u8,
+    unix_sock: Option<&str>,
 ) -> Result<TlsFetchResult> {
-    // Preferred path: raw TLS probe for accurate record sizing
-    match fetch_via_raw_tls(host, port, sni, connect_timeout).await {
-        Ok(res) => return Ok(res),
-        Err(e) => {
-            warn!(sni = %sni, error = %e, "Raw TLS fetch failed, falling back to rustls");
+    #[cfg(unix)]
+    if let Some(sock_path) = unix_sock {
+        match timeout(connect_timeout, UnixStream::connect(sock_path)).await {
+            Ok(Ok(stream)) => {
+                debug!(
+                    sni = %sni,
+                    sock = %sock_path,
+                    "Raw TLS fetch using mask unix socket"
+                );
+                return fetch_via_raw_tls_stream(stream, sni, connect_timeout, proxy_protocol).await;
+            }
+            Ok(Err(e)) => {
+                warn!(
+                    sni = %sni,
+                    sock = %sock_path,
+                    error = %e,
+                    "Raw TLS unix socket connect failed, falling back to TCP"
+                );
+            }
+            Err(_) => {
+                warn!(
+                    sni = %sni,
+                    sock = %sock_path,
+                    "Raw TLS unix socket connect timed out, falling back to TCP"
+                );
+            }
         }
     }
 
-    // Fallback: rustls handshake to at least get certificate sizes
-    let stream = if let Some(manager) = upstream {
-        // Resolve host to SocketAddr
-        if let Ok(mut addrs) = tokio::net::lookup_host((host, port)).await {
-            if let Some(addr) = addrs.find(|a| a.is_ipv4()) {
-                match manager.connect(addr, None, None).await {
-                    Ok(s) => s,
-                    Err(e) => {
-                        warn!(sni = %sni, error = %e, "Upstream connect failed, using direct connect");
-                        timeout(connect_timeout, TcpStream::connect((host, port))).await??
-                    }
-                }
-            } else {
-                timeout(connect_timeout, TcpStream::connect((host, port))).await??
-            }
-        } else {
-            timeout(connect_timeout, TcpStream::connect((host, port))).await??
-        }
-    } else {
-        timeout(connect_timeout, TcpStream::connect((host, port))).await??
-    };
+    #[cfg(not(unix))]
+    let _ = unix_sock;
+
+    let stream = connect_tcp_with_upstream(host, port, connect_timeout, upstream).await?;
+    fetch_via_raw_tls_stream(stream, sni, connect_timeout, proxy_protocol).await
+}
+
+async fn fetch_via_rustls_stream<S>(
+    mut stream: S,
+    host: &str,
+    sni: &str,
+    proxy_protocol: u8,
+) -> Result<TlsFetchResult>
+where
+    S: AsyncRead + AsyncWrite + Unpin,
+{
+    // rustls handshake path for certificate and basic negotiated metadata.
+    if proxy_protocol > 0 {
+        let header = match proxy_protocol {
+            2 => ProxyProtocolV2Builder::new().build(),
+            _ => ProxyProtocolV1Builder::new().build(),
+        };
+        stream.write_all(&header).await?;
+        stream.flush().await?;
+    }
 
     let config = build_client_config();
     let connector = TlsConnector::from(config);
@@ -416,7 +552,7 @@ pub async fn fetch_real_tls(
         .or_else(|_| ServerName::try_from(host.to_owned()))
         .map_err(|_| RustlsError::General("invalid SNI".into()))?;
 
-    let tls_stream: TlsStream<TcpStream> = connector.connect(server_name, stream).await?;
+    let tls_stream: TlsStream<S> = connector.connect(server_name, stream).await?;
 
     // Extract negotiated parameters and certificates
     let (_io, session) = tls_stream.get_ref();
@@ -429,8 +565,19 @@ pub async fn fetch_real_tls(
         .peer_certificates()
         .map(|slice| slice.to_vec())
         .unwrap_or_default();
+    let cert_chain_der: Vec<Vec<u8>> = certs.iter().map(|c| c.as_ref().to_vec()).collect();
+    let cert_payload = encode_tls13_certificate_message(&cert_chain_der).map(|certificate_message| {
+        TlsCertPayload {
+            cert_chain_der: cert_chain_der.clone(),
+            certificate_message,
+        }
+    });
 
-    let total_cert_len: usize = certs.iter().map(|c| c.len()).sum::<usize>().max(1024);
+    let total_cert_len = cert_payload
+        .as_ref()
+        .map(|payload| payload.certificate_message.len())
+        .unwrap_or_else(|| cert_chain_der.iter().map(Vec::len).sum::<usize>())
+        .max(1024);
     let cert_info = parse_cert_info(&certs);
 
     // Heuristic: split across two records if large to mimic real servers a bit.
@@ -453,6 +600,7 @@ pub async fn fetch_real_tls(
         sni = %sni,
         len = total_cert_len,
         cipher = format!("0x{:04x}", u16::from_be_bytes(cipher_suite)),
+        has_cert_payload = cert_payload.is_some(),
         "Fetched TLS metadata via rustls"
     );
 
@@ -461,5 +609,148 @@ pub async fn fetch_real_tls(
         app_data_records_sizes: app_data_records_sizes.clone(),
         total_app_data_len: app_data_records_sizes.iter().sum(),
         cert_info,
+        cert_payload,
     })
 }
+
+async fn fetch_via_rustls(
+    host: &str,
+    port: u16,
+    sni: &str,
+    connect_timeout: Duration,
+    upstream: Option<std::sync::Arc<crate::transport::UpstreamManager>>,
+    proxy_protocol: u8,
+    unix_sock: Option<&str>,
+) -> Result<TlsFetchResult> {
+    #[cfg(unix)]
+    if let Some(sock_path) = unix_sock {
+        match timeout(connect_timeout, UnixStream::connect(sock_path)).await {
+            Ok(Ok(stream)) => {
+                debug!(
+                    sni = %sni,
+                    sock = %sock_path,
+                    "Rustls fetch using mask unix socket"
+                );
+                return fetch_via_rustls_stream(stream, host, sni, proxy_protocol).await;
+            }
+            Ok(Err(e)) => {
+                warn!(
+                    sni = %sni,
+                    sock = %sock_path,
+                    error = %e,
+                    "Rustls unix socket connect failed, falling back to TCP"
+                );
+            }
+            Err(_) => {
+                warn!(
+                    sni = %sni,
+                    sock = %sock_path,
+                    "Rustls unix socket connect timed out, falling back to TCP"
+                );
+            }
+        }
+    }
+
+    #[cfg(not(unix))]
+    let _ = unix_sock;
+
+    let stream = connect_tcp_with_upstream(host, port, connect_timeout, upstream).await?;
+    fetch_via_rustls_stream(stream, host, sni, proxy_protocol).await
+}
+
+/// Fetch real TLS metadata for the given SNI.
+///
+/// Strategy:
+/// 1) Probe raw TLS for realistic ServerHello and ApplicationData record sizes.
+/// 2) Fetch certificate chain via rustls to build cert payload.
+/// 3) Merge both when possible; otherwise auto-fallback to whichever succeeded.
+pub async fn fetch_real_tls(
+    host: &str,
+    port: u16,
+    sni: &str,
+    connect_timeout: Duration,
+    upstream: Option<std::sync::Arc<crate::transport::UpstreamManager>>,
+    proxy_protocol: u8,
+    unix_sock: Option<&str>,
+) -> Result<TlsFetchResult> {
+    let raw_result = match fetch_via_raw_tls(
+        host,
+        port,
+        sni,
+        connect_timeout,
+        upstream.clone(),
+        proxy_protocol,
+        unix_sock,
+    )
+    .await
+    {
+        Ok(res) => Some(res),
+        Err(e) => {
+            warn!(sni = %sni, error = %e, "Raw TLS fetch failed");
+            None
+        }
+    };
+
+    match fetch_via_rustls(
+        host,
+        port,
+        sni,
+        connect_timeout,
+        upstream,
+        proxy_protocol,
+        unix_sock,
+    )
+    .await
+    {
+        Ok(rustls_result) => {
+            if let Some(mut raw) = raw_result {
+                raw.cert_info = rustls_result.cert_info;
+                raw.cert_payload = rustls_result.cert_payload;
+                debug!(sni = %sni, "Fetched TLS metadata via raw probe + rustls cert chain");
+                Ok(raw)
+            } else {
+                Ok(rustls_result)
+            }
+        }
+        Err(e) => {
+            if let Some(raw) = raw_result {
+                warn!(sni = %sni, error = %e, "Rustls cert fetch failed, using raw TLS metadata only");
+                Ok(raw)
+            } else {
+                Err(e)
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::encode_tls13_certificate_message;
+
+    fn read_u24(bytes: &[u8]) -> usize {
+        ((bytes[0] as usize) << 16) | ((bytes[1] as usize) << 8) | (bytes[2] as usize)
+    }
+
+    #[test]
+    fn test_encode_tls13_certificate_message_single_cert() {
+        let cert = vec![0x30, 0x03, 0x02, 0x01, 0x01];
+        let message = encode_tls13_certificate_message(&[cert.clone()]).expect("message");
+
+        assert_eq!(message[0], 0x0b);
+        assert_eq!(read_u24(&message[1..4]), message.len() - 4);
+        assert_eq!(message[4], 0x00);
+
+        let cert_list_len = read_u24(&message[5..8]);
+        assert_eq!(cert_list_len, cert.len() + 5);
+
+        let cert_len = read_u24(&message[8..11]);
+        assert_eq!(cert_len, cert.len());
+        assert_eq!(&message[11..11 + cert.len()], cert.as_slice());
+        assert_eq!(&message[11 + cert.len()..13 + cert.len()], &[0x00, 0x00]);
+    }
+
+    #[test]
+    fn test_encode_tls13_certificate_message_empty_chain() {
+        assert!(encode_tls13_certificate_message(&[]).is_none());
+    }
+}

src/tls_front/mod.rs

@@ -4,4 +4,5 @@ pub mod fetcher;
 pub mod emulator;
 
 pub use cache::TlsFrontCache;
+#[allow(unused_imports)]
 pub use types::{CachedTlsData, TlsFetchResult};

src/tls_front/types.rs

@@ -29,11 +29,23 @@ pub struct ParsedCertificateInfo {
     pub san_names: Vec<String>,
 }
 
+/// TLS certificate payload captured from profiled upstream.
+///
+/// `certificate_message` stores an encoded TLS 1.3 Certificate handshake
+/// message body that can be replayed as opaque ApplicationData bytes in FakeTLS.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct TlsCertPayload {
+    pub cert_chain_der: Vec<Vec<u8>>,
+    pub certificate_message: Vec<u8>,
+}
+
 /// Cached data per SNI used by the emulator.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct CachedTlsData {
     pub server_hello_template: ParsedServerHello,
     pub cert_info: Option<ParsedCertificateInfo>,
+    #[serde(default)]
+    pub cert_payload: Option<TlsCertPayload>,
     pub app_data_records_sizes: Vec<usize>,
     pub total_app_data_len: usize,
     #[serde(default = "now_system_time", skip_serializing, skip_deserializing)]
@@ -52,4 +64,5 @@ pub struct TlsFetchResult {
     pub app_data_records_sizes: Vec<usize>,
     pub total_app_data_len: usize,
     pub cert_info: Option<ParsedCertificateInfo>,
+    pub cert_payload: Option<TlsCertPayload>,
 }

src/transport/middle_proxy/codec.rs

@@ -1,6 +1,6 @@
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
 
-use crate::crypto::{AesCbc, crc32};
+use crate::crypto::{AesCbc, crc32, crc32c};
 use crate::error::{ProxyError, Result};
 use crate::protocol::constants::*;
 
@@ -8,17 +8,46 @@ use crate::protocol::constants::*;
 pub(crate) enum WriterCommand {
     Data(Vec<u8>),
     DataAndFlush(Vec<u8>),
-    Keepalive,
     Close,
 }
 
-pub(crate) fn build_rpc_frame(seq_no: i32, payload: &[u8]) -> Vec<u8> {
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) enum RpcChecksumMode {
+    Crc32,
+    Crc32c,
+}
+
+impl RpcChecksumMode {
+    pub(crate) fn from_handshake_flags(flags: u32) -> Self {
+        if (flags & rpc_crypto_flags::USE_CRC32C) != 0 {
+            Self::Crc32c
+        } else {
+            Self::Crc32
+        }
+    }
+
+    pub(crate) fn advertised_flags(self) -> u32 {
+        match self {
+            Self::Crc32 => 0,
+            Self::Crc32c => rpc_crypto_flags::USE_CRC32C,
+        }
+    }
+}
+
+pub(crate) fn rpc_crc(mode: RpcChecksumMode, data: &[u8]) -> u32 {
+    match mode {
+        RpcChecksumMode::Crc32 => crc32(data),
+        RpcChecksumMode::Crc32c => crc32c(data),
+    }
+}
+
+pub(crate) fn build_rpc_frame(seq_no: i32, payload: &[u8], crc_mode: RpcChecksumMode) -> Vec<u8> {
     let total_len = (4 + 4 + payload.len() + 4) as u32;
     let mut frame = Vec::with_capacity(total_len as usize);
     frame.extend_from_slice(&total_len.to_le_bytes());
     frame.extend_from_slice(&seq_no.to_le_bytes());
     frame.extend_from_slice(payload);
-    let c = crc32(&frame);
+    let c = rpc_crc(crc_mode, &frame);
     frame.extend_from_slice(&c.to_le_bytes());
     frame
 }
@@ -45,7 +74,7 @@ pub(crate) async fn read_rpc_frame_plaintext(
 
     let crc_offset = total_len - 4;
     let expected_crc = u32::from_le_bytes(full[crc_offset..crc_offset + 4].try_into().unwrap());
-    let actual_crc = crc32(&full[..crc_offset]);
+    let actual_crc = rpc_crc(RpcChecksumMode::Crc32, &full[..crc_offset]);
     if expected_crc != actual_crc {
         return Err(ProxyError::InvalidHandshake(format!(
             "CRC mismatch: 0x{expected_crc:08x} vs 0x{actual_crc:08x}"
@@ -95,26 +124,53 @@ pub(crate) fn build_handshake_payload(
     our_port: u16,
     peer_ip: [u8; 4],
     peer_port: u16,
+    flags: u32,
 ) -> [u8; 32] {
     let mut p = [0u8; 32];
     p[0..4].copy_from_slice(&RPC_HANDSHAKE_U32.to_le_bytes());
+    p[4..8].copy_from_slice(&flags.to_le_bytes());
 
-    // Keep C memory layout compatibility for PID IPv4 bytes.
+    // process_id sender_pid
     p[8..12].copy_from_slice(&our_ip);
     p[12..14].copy_from_slice(&our_port.to_le_bytes());
-    let pid = (std::process::id() & 0xffff) as u16;
-    p[14..16].copy_from_slice(&pid.to_le_bytes());
-    let utime = std::time::SystemTime::now()
-        .duration_since(std::time::UNIX_EPOCH)
-        .unwrap_or_default()
-        .as_secs() as u32;
-    p[16..20].copy_from_slice(&utime.to_le_bytes());
+    p[14..16].copy_from_slice(&process_pid16().to_le_bytes());
+    p[16..20].copy_from_slice(&process_utime().to_le_bytes());
 
+    // process_id peer_pid
     p[20..24].copy_from_slice(&peer_ip);
     p[24..26].copy_from_slice(&peer_port.to_le_bytes());
+    p[26..28].copy_from_slice(&0u16.to_le_bytes());
+    p[28..32].copy_from_slice(&0u32.to_le_bytes());
     p
 }
 
+pub(crate) fn parse_handshake_flags(payload: &[u8]) -> Result<u32> {
+    if payload.len() != 32 {
+        return Err(ProxyError::InvalidHandshake(format!(
+            "Bad handshake payload len: {}",
+            payload.len()
+        )));
+    }
+    let hs_type = u32::from_le_bytes(payload[0..4].try_into().unwrap());
+    if hs_type != RPC_HANDSHAKE_U32 {
+        return Err(ProxyError::InvalidHandshake(format!(
+            "Expected HANDSHAKE 0x{RPC_HANDSHAKE_U32:08x}, got 0x{hs_type:08x}"
+        )));
+    }
+    Ok(u32::from_le_bytes(payload[4..8].try_into().unwrap()))
+}
+
+fn process_pid16() -> u16 {
+    (std::process::id() & 0xffff) as u16
+}
+
+fn process_utime() -> u32 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs() as u32
+}
+
 pub(crate) fn cbc_encrypt_padded(
     key: &[u8; 32],
     iv: &[u8; 16],
@@ -160,12 +216,13 @@ pub(crate) struct RpcWriter {
     pub(crate) key: [u8; 32],
     pub(crate) iv: [u8; 16],
     pub(crate) seq_no: i32,
+    pub(crate) crc_mode: RpcChecksumMode,
 }
 
 impl RpcWriter {
     pub(crate) async fn send(&mut self, payload: &[u8]) -> Result<()> {
-        let frame = build_rpc_frame(self.seq_no, payload);
-        self.seq_no += 1;
+        let frame = build_rpc_frame(self.seq_no, payload, self.crc_mode);
+        self.seq_no = self.seq_no.wrapping_add(1);
 
         let pad = (16 - (frame.len() % 16)) % 16;
         let mut buf = frame;
@@ -189,12 +246,4 @@ impl RpcWriter {
         self.send(payload).await?;
         self.writer.flush().await.map_err(ProxyError::Io)
     }
-
-    pub(crate) async fn send_keepalive(&mut self, payload: [u8; 4]) -> Result<()> {
-        // Keepalive is a frame with fl == 4 and 4 bytes payload.
-        let mut frame = Vec::with_capacity(8);
-        frame.extend_from_slice(&4u32.to_le_bytes());
-        frame.extend_from_slice(&payload);
-        self.send(&frame).await
-    }
 }

src/transport/middle_proxy/config_updater.rs

@@ -1,16 +1,20 @@
 use std::collections::HashMap;
+use std::hash::{DefaultHasher, Hash, Hasher};
 use std::net::IpAddr;
+use std::path::Path;
 use std::sync::Arc;
 use std::time::Duration;
 
 use httpdate;
+use tokio::sync::{mpsc, watch};
 use tracing::{debug, info, warn};
 
+use crate::config::ProxyConfig;
 use crate::error::Result;
 
 use super::MePool;
-use super::secret::download_proxy_secret;
-use crate::crypto::SecureRandom;
+use super::rotation::{MeReinitTrigger, enqueue_reinit_trigger};
+use super::secret::download_proxy_secret_with_max_len;
 use std::time::SystemTime;
 
 async fn retry_fetch(url: &str) -> Option<ProxyConfigData> {
@@ -35,17 +39,188 @@ async fn retry_fetch(url: &str) -> Option<ProxyConfigData> {
 pub struct ProxyConfigData {
     pub map: HashMap<i32, Vec<(IpAddr, u16)>>,
     pub default_dc: Option<i32>,
+    pub http_status: u16,
+    pub proxy_for_lines: u32,
+}
+
+pub fn parse_proxy_config_text(text: &str, http_status: u16) -> ProxyConfigData {
+    let mut map: HashMap<i32, Vec<(IpAddr, u16)>> = HashMap::new();
+    let mut proxy_for_lines: u32 = 0;
+    for line in text.lines() {
+        if let Some((dc, ip, port)) = parse_proxy_line(line) {
+            map.entry(dc).or_default().push((ip, port));
+            proxy_for_lines = proxy_for_lines.saturating_add(1);
+        }
+    }
+
+    let default_dc = text.lines().find_map(|l| {
+        let t = l.trim();
+        if let Some(rest) = t.strip_prefix("default") {
+            return rest.trim().trim_end_matches(';').parse::<i32>().ok();
+        }
+        None
+    });
+
+    ProxyConfigData {
+        map,
+        default_dc,
+        http_status,
+        proxy_for_lines,
+    }
+}
+
+pub async fn load_proxy_config_cache(path: &str) -> Result<ProxyConfigData> {
+    let text = tokio::fs::read_to_string(path).await.map_err(|e| {
+        crate::error::ProxyError::Proxy(format!("read proxy-config cache '{path}' failed: {e}"))
+    })?;
+    Ok(parse_proxy_config_text(&text, 200))
+}
+
+pub async fn save_proxy_config_cache(path: &str, raw_text: &str) -> Result<()> {
+    if let Some(parent) = Path::new(path).parent()
+        && !parent.as_os_str().is_empty()
+    {
+        tokio::fs::create_dir_all(parent).await.map_err(|e| {
+            crate::error::ProxyError::Proxy(format!(
+                "create proxy-config cache dir '{}' failed: {e}",
+                parent.display()
+            ))
+        })?;
+    }
+
+    tokio::fs::write(path, raw_text).await.map_err(|e| {
+        crate::error::ProxyError::Proxy(format!("write proxy-config cache '{path}' failed: {e}"))
+    })?;
+    Ok(())
+}
+
+pub async fn fetch_proxy_config_with_raw(url: &str) -> Result<(ProxyConfigData, String)> {
+    let resp = reqwest::get(url)
+        .await
+        .map_err(|e| crate::error::ProxyError::Proxy(format!("fetch_proxy_config GET failed: {e}")))?
+        ;
+    let http_status = resp.status().as_u16();
+
+    if let Some(date) = resp.headers().get(reqwest::header::DATE)
+        && let Ok(date_str) = date.to_str()
+        && let Ok(server_time) = httpdate::parse_http_date(date_str)
+        && let Ok(skew) = SystemTime::now().duration_since(server_time).or_else(|e| {
+            server_time.duration_since(SystemTime::now()).map_err(|_| e)
+        })
+    {
+        let skew_secs = skew.as_secs();
+        if skew_secs > 60 {
+            warn!(skew_secs, "Time skew >60s detected from fetch_proxy_config Date header");
+        } else if skew_secs > 30 {
+            warn!(skew_secs, "Time skew >30s detected from fetch_proxy_config Date header");
+        }
+    }
+
+    let text = resp
+        .text()
+        .await
+        .map_err(|e| crate::error::ProxyError::Proxy(format!("fetch_proxy_config read failed: {e}")))?;
+    let parsed = parse_proxy_config_text(&text, http_status);
+    Ok((parsed, text))
+}
+
+#[derive(Debug, Default)]
+struct StableSnapshot {
+    candidate_hash: Option<u64>,
+    candidate_hits: u8,
+    applied_hash: Option<u64>,
+}
+
+impl StableSnapshot {
+    fn observe(&mut self, hash: u64) -> u8 {
+        if self.candidate_hash == Some(hash) {
+            self.candidate_hits = self.candidate_hits.saturating_add(1);
+        } else {
+            self.candidate_hash = Some(hash);
+            self.candidate_hits = 1;
+        }
+        self.candidate_hits
+    }
+
+    fn is_applied(&self, hash: u64) -> bool {
+        self.applied_hash == Some(hash)
+    }
+
+    fn mark_applied(&mut self, hash: u64) {
+        self.applied_hash = Some(hash);
+    }
+}
+
+#[derive(Debug, Default)]
+struct UpdaterState {
+    config_v4: StableSnapshot,
+    config_v6: StableSnapshot,
+    secret: StableSnapshot,
+    last_map_apply_at: Option<tokio::time::Instant>,
+}
+
+fn hash_proxy_config(cfg: &ProxyConfigData) -> u64 {
+    let mut hasher = DefaultHasher::new();
+    cfg.default_dc.hash(&mut hasher);
+
+    let mut by_dc: Vec<(i32, Vec<(IpAddr, u16)>)> =
+        cfg.map.iter().map(|(dc, addrs)| (*dc, addrs.clone())).collect();
+    by_dc.sort_by_key(|(dc, _)| *dc);
+    for (dc, mut addrs) in by_dc {
+        dc.hash(&mut hasher);
+        addrs.sort_unstable();
+        for (ip, port) in addrs {
+            ip.hash(&mut hasher);
+            port.hash(&mut hasher);
+        }
+    }
+
+    hasher.finish()
+}
+
+fn hash_secret(secret: &[u8]) -> u64 {
+    let mut hasher = DefaultHasher::new();
+    secret.hash(&mut hasher);
+    hasher.finish()
+}
+
+fn map_apply_cooldown_ready(
+    last_applied: Option<tokio::time::Instant>,
+    cooldown: Duration,
+) -> bool {
+    if cooldown.is_zero() {
+        return true;
+    }
+    match last_applied {
+        Some(ts) => ts.elapsed() >= cooldown,
+        None => true,
+    }
+}
+
+fn map_apply_cooldown_remaining_secs(
+    last_applied: tokio::time::Instant,
+    cooldown: Duration,
+) -> u64 {
+    if cooldown.is_zero() {
+        return 0;
+    }
+    cooldown
+        .checked_sub(last_applied.elapsed())
+        .map(|d| d.as_secs())
+        .unwrap_or(0)
 }
 
 fn parse_host_port(s: &str) -> Option<(IpAddr, u16)> {
-    if let Some(bracket_end) = s.rfind(']') {
-        if s.starts_with('[') && bracket_end + 1 < s.len() && s.as_bytes().get(bracket_end + 1) == Some(&b':') {
-            let host = &s[1..bracket_end];
-            let port_str = &s[bracket_end + 2..];
-            let ip = host.parse::<IpAddr>().ok()?;
-            let port = port_str.parse::<u16>().ok()?;
-            return Some((ip, port));
-        }
+    if let Some(bracket_end) = s.rfind(']')
+        && s.starts_with('[')
+        && bracket_end + 1 < s.len()
+        && s.as_bytes().get(bracket_end + 1) == Some(&b':')
+    {
+        let host = &s[1..bracket_end];
+        let port_str = &s[bracket_end + 2..];
+        let ip = host.parse::<IpAddr>().ok()?;
+        let port = port_str.parse::<u16>().ok()?;
+        return Some((ip, port));
     }
 
     let idx = s.rfind(':')?;
@@ -77,100 +252,319 @@ fn parse_proxy_line(line: &str) -> Option<(i32, IpAddr, u16)> {
 }
 
 pub async fn fetch_proxy_config(url: &str) -> Result<ProxyConfigData> {
-    let resp = reqwest::get(url)
+    fetch_proxy_config_with_raw(url)
         .await
-        .map_err(|e| crate::error::ProxyError::Proxy(format!("fetch_proxy_config GET failed: {e}")))?
-        ;
+        .map(|(parsed, _raw)| parsed)
+}
 
-    if let Some(date) = resp.headers().get(reqwest::header::DATE) {
-        if let Ok(date_str) = date.to_str() {
-            if let Ok(server_time) = httpdate::parse_http_date(date_str) {
-                if let Ok(skew) = SystemTime::now().duration_since(server_time).or_else(|e| {
-                    server_time.duration_since(SystemTime::now()).map_err(|_| e)
-                }) {
-                    let skew_secs = skew.as_secs();
-                    if skew_secs > 60 {
-                        warn!(skew_secs, "Time skew >60s detected from fetch_proxy_config Date header");
-                    } else if skew_secs > 30 {
-                        warn!(skew_secs, "Time skew >30s detected from fetch_proxy_config Date header");
+fn snapshot_passes_guards(
+    cfg: &ProxyConfig,
+    snapshot: &ProxyConfigData,
+    snapshot_name: &'static str,
+) -> bool {
+    if cfg.general.me_snapshot_require_http_2xx
+        && !(200..=299).contains(&snapshot.http_status)
+    {
+        warn!(
+            snapshot = snapshot_name,
+            http_status = snapshot.http_status,
+            "ME snapshot rejected by non-2xx HTTP status"
+        );
+        return false;
+    }
+
+    let min_proxy_for = cfg.general.me_snapshot_min_proxy_for_lines;
+    if snapshot.proxy_for_lines < min_proxy_for {
+        warn!(
+            snapshot = snapshot_name,
+            parsed_proxy_for_lines = snapshot.proxy_for_lines,
+            min_proxy_for_lines = min_proxy_for,
+            "ME snapshot rejected by proxy_for line floor"
+        );
+        return false;
+    }
+
+    true
+}
+
+async fn run_update_cycle(
+    pool: &Arc<MePool>,
+    cfg: &ProxyConfig,
+    state: &mut UpdaterState,
+    reinit_tx: &mpsc::Sender<MeReinitTrigger>,
+) {
+    pool.update_runtime_reinit_policy(
+        cfg.general.hardswap,
+        cfg.general.me_pool_drain_ttl_secs,
+        cfg.general.effective_me_pool_force_close_secs(),
+        cfg.general.me_pool_min_fresh_ratio,
+        cfg.general.me_hardswap_warmup_delay_min_ms,
+        cfg.general.me_hardswap_warmup_delay_max_ms,
+        cfg.general.me_hardswap_warmup_extra_passes,
+        cfg.general.me_hardswap_warmup_pass_backoff_base_ms,
+        cfg.general.me_bind_stale_mode,
+        cfg.general.me_bind_stale_ttl_secs,
+        cfg.general.me_secret_atomic_snapshot,
+        cfg.general.me_deterministic_writer_sort,
+        cfg.general.me_single_endpoint_shadow_writers,
+        cfg.general.me_single_endpoint_outage_mode_enabled,
+        cfg.general.me_single_endpoint_outage_disable_quarantine,
+        cfg.general.me_single_endpoint_outage_backoff_min_ms,
+        cfg.general.me_single_endpoint_outage_backoff_max_ms,
+        cfg.general.me_single_endpoint_shadow_rotate_every_secs,
+        cfg.general.me_floor_mode,
+        cfg.general.me_adaptive_floor_idle_secs,
+        cfg.general.me_adaptive_floor_min_writers_single_endpoint,
+        cfg.general.me_adaptive_floor_min_writers_multi_endpoint,
+        cfg.general.me_adaptive_floor_recover_grace_secs,
+        cfg.general.me_adaptive_floor_writers_per_core_total,
+        cfg.general.me_adaptive_floor_cpu_cores_override,
+        cfg.general.me_adaptive_floor_max_extra_writers_single_per_core,
+        cfg.general.me_adaptive_floor_max_extra_writers_multi_per_core,
+    );
+
+    let required_cfg_snapshots = cfg.general.me_config_stable_snapshots.max(1);
+    let required_secret_snapshots = cfg.general.proxy_secret_stable_snapshots.max(1);
+    let apply_cooldown = Duration::from_secs(cfg.general.me_config_apply_cooldown_secs);
+    let mut maps_changed = false;
+
+    let mut ready_v4: Option<(ProxyConfigData, u64)> = None;
+    let cfg_v4 = retry_fetch("https://core.telegram.org/getProxyConfig").await;
+    if let Some(cfg_v4) = cfg_v4 {
+        if snapshot_passes_guards(cfg, &cfg_v4, "getProxyConfig") {
+            let cfg_v4_hash = hash_proxy_config(&cfg_v4);
+            let stable_hits = state.config_v4.observe(cfg_v4_hash);
+            if stable_hits < required_cfg_snapshots {
+                debug!(
+                    stable_hits,
+                    required_cfg_snapshots,
+                    snapshot = format_args!("0x{cfg_v4_hash:016x}"),
+                    "ME config v4 candidate observed"
+                );
+            } else if state.config_v4.is_applied(cfg_v4_hash) {
+                debug!(
+                    snapshot = format_args!("0x{cfg_v4_hash:016x}"),
+                    "ME config v4 stable snapshot already applied"
+                );
+            } else {
+                ready_v4 = Some((cfg_v4, cfg_v4_hash));
+            }
+        }
+    }
+
+    let mut ready_v6: Option<(ProxyConfigData, u64)> = None;
+    let cfg_v6 = retry_fetch("https://core.telegram.org/getProxyConfigV6").await;
+    if let Some(cfg_v6) = cfg_v6 {
+        if snapshot_passes_guards(cfg, &cfg_v6, "getProxyConfigV6") {
+            let cfg_v6_hash = hash_proxy_config(&cfg_v6);
+            let stable_hits = state.config_v6.observe(cfg_v6_hash);
+            if stable_hits < required_cfg_snapshots {
+                debug!(
+                    stable_hits,
+                    required_cfg_snapshots,
+                    snapshot = format_args!("0x{cfg_v6_hash:016x}"),
+                    "ME config v6 candidate observed"
+                );
+            } else if state.config_v6.is_applied(cfg_v6_hash) {
+                debug!(
+                    snapshot = format_args!("0x{cfg_v6_hash:016x}"),
+                    "ME config v6 stable snapshot already applied"
+                );
+            } else {
+                ready_v6 = Some((cfg_v6, cfg_v6_hash));
+            }
+        }
+    }
+
+    if ready_v4.is_some() || ready_v6.is_some() {
+        if map_apply_cooldown_ready(state.last_map_apply_at, apply_cooldown) {
+            let update_v4 = ready_v4
+                .as_ref()
+                .map(|(snapshot, _)| snapshot.map.clone())
+                .unwrap_or_default();
+            let update_v6 = ready_v6
+                .as_ref()
+                .map(|(snapshot, _)| snapshot.map.clone());
+            let update_is_empty =
+                update_v4.is_empty() && update_v6.as_ref().is_none_or(|v| v.is_empty());
+            let apply_outcome = if update_is_empty && !cfg.general.me_snapshot_reject_empty_map {
+                super::pool_config::SnapshotApplyOutcome::AppliedNoDelta
+            } else {
+                pool.update_proxy_maps(update_v4, update_v6).await
+            };
+
+            if matches!(
+                apply_outcome,
+                super::pool_config::SnapshotApplyOutcome::RejectedEmpty
+            ) {
+                warn!("ME config stable snapshot rejected (empty endpoint map)");
+            } else {
+                if let Some((snapshot, hash)) = ready_v4 {
+                    if let Some(dc) = snapshot.default_dc {
+                        pool.default_dc
+                            .store(dc, std::sync::atomic::Ordering::Relaxed);
+                    }
+                    state.config_v4.mark_applied(hash);
+                }
+
+                if let Some((_snapshot, hash)) = ready_v6 {
+                    state.config_v6.mark_applied(hash);
+                }
+
+                state.last_map_apply_at = Some(tokio::time::Instant::now());
+
+                if apply_outcome.changed() {
+                    maps_changed = true;
+                    info!("ME config update applied after stable-gate");
+                } else {
+                    debug!("ME config stable-gate applied with no map delta");
+                }
+            }
+        } else if let Some(last) = state.last_map_apply_at {
+            let wait_secs = map_apply_cooldown_remaining_secs(last, apply_cooldown);
+            debug!(
+                wait_secs,
+                "ME config stable snapshot deferred by cooldown"
+            );
+        }
+    }
+
+    if maps_changed {
+        enqueue_reinit_trigger(reinit_tx, MeReinitTrigger::MapChanged);
+    }
+
+    pool.reset_stun_state();
+
+    if cfg.general.proxy_secret_rotate_runtime {
+        match download_proxy_secret_with_max_len(cfg.general.proxy_secret_len_max).await {
+            Ok(secret) => {
+                let secret_hash = hash_secret(&secret);
+                let stable_hits = state.secret.observe(secret_hash);
+                if stable_hits < required_secret_snapshots {
+                    debug!(
+                        stable_hits,
+                        required_secret_snapshots,
+                        snapshot = format_args!("0x{secret_hash:016x}"),
+                        "proxy-secret candidate observed"
+                    );
+                } else if state.secret.is_applied(secret_hash) {
+                    debug!(
+                        snapshot = format_args!("0x{secret_hash:016x}"),
+                        "proxy-secret stable snapshot already applied"
+                    );
+                } else {
+                    let rotated = pool.update_secret(secret).await;
+                    state.secret.mark_applied(secret_hash);
+                    if rotated {
+                        info!("proxy-secret rotated after stable-gate");
+                    } else {
+                        debug!("proxy-secret stable snapshot confirmed as unchanged");
                     }
                 }
             }
+            Err(e) => warn!(error = %e, "proxy-secret update failed"),
         }
+    } else {
+        debug!("proxy-secret runtime rotation disabled by config");
     }
-
-    let text = resp
-        .text()
-        .await
-        .map_err(|e| crate::error::ProxyError::Proxy(format!("fetch_proxy_config read failed: {e}")))?;
-
-    let mut map: HashMap<i32, Vec<(IpAddr, u16)>> = HashMap::new();
-    for line in text.lines() {
-        if let Some((dc, ip, port)) = parse_proxy_line(line) {
-            map.entry(dc).or_default().push((ip, port));
-        }
-    }
-
-    let default_dc = text
-        .lines()
-        .find_map(|l| {
-            let t = l.trim();
-            if let Some(rest) = t.strip_prefix("default") {
-                return rest
-                    .trim()
-                    .trim_end_matches(';')
-                    .parse::<i32>()
-                    .ok();
-            }
-            None
-        });
-
-    Ok(ProxyConfigData { map, default_dc })
 }
 
-pub async fn me_config_updater(pool: Arc<MePool>, rng: Arc<SecureRandom>, interval: Duration) {
-    let mut tick = tokio::time::interval(interval);
-    // skip immediate tick to avoid double-fetch right after startup
-    tick.tick().await;
+pub async fn me_config_updater(
+    pool: Arc<MePool>,
+    mut config_rx: watch::Receiver<Arc<ProxyConfig>>,
+    reinit_tx: mpsc::Sender<MeReinitTrigger>,
+) {
+    let mut state = UpdaterState::default();
+    let mut update_every_secs = config_rx
+        .borrow()
+        .general
+        .effective_update_every_secs()
+        .max(1);
+    let mut update_every = Duration::from_secs(update_every_secs);
+    let mut next_tick = tokio::time::Instant::now() + update_every;
+    info!(update_every_secs, "ME config updater started");
+
     loop {
-        tick.tick().await;
+        let sleep = tokio::time::sleep_until(next_tick);
+        tokio::pin!(sleep);
 
-        // Update proxy config v4
-        let cfg_v4 = retry_fetch("https://core.telegram.org/getProxyConfig").await;
-        if let Some(cfg) = cfg_v4 {
-            let changed = pool.update_proxy_maps(cfg.map.clone(), None).await;
-            if let Some(dc) = cfg.default_dc {
-                pool.default_dc.store(dc, std::sync::atomic::Ordering::Relaxed);
+        tokio::select! {
+            _ = &mut sleep => {
+                let cfg = config_rx.borrow().clone();
+                run_update_cycle(&pool, cfg.as_ref(), &mut state, &reinit_tx).await;
+                let refreshed_secs = cfg.general.effective_update_every_secs().max(1);
+                if refreshed_secs != update_every_secs {
+                    info!(
+                        old_update_every_secs = update_every_secs,
+                        new_update_every_secs = refreshed_secs,
+                        "ME config updater interval changed"
+                    );
+                    update_every_secs = refreshed_secs;
+                    update_every = Duration::from_secs(update_every_secs);
+                }
+                next_tick = tokio::time::Instant::now() + update_every;
             }
-            if changed {
-                info!("ME config updated (v4), reconciling connections");
-                pool.reconcile_connections(&rng).await;
-            } else {
-                debug!("ME config v4 unchanged");
-            }
-        }
+            changed = config_rx.changed() => {
+                if changed.is_err() {
+                    warn!("ME config updater stopped: config channel closed");
+                    break;
+                }
+                let cfg = config_rx.borrow().clone();
+                pool.update_runtime_reinit_policy(
+                    cfg.general.hardswap,
+                    cfg.general.me_pool_drain_ttl_secs,
+                    cfg.general.effective_me_pool_force_close_secs(),
+                    cfg.general.me_pool_min_fresh_ratio,
+                    cfg.general.me_hardswap_warmup_delay_min_ms,
+                    cfg.general.me_hardswap_warmup_delay_max_ms,
+                    cfg.general.me_hardswap_warmup_extra_passes,
+                    cfg.general.me_hardswap_warmup_pass_backoff_base_ms,
+                    cfg.general.me_bind_stale_mode,
+                    cfg.general.me_bind_stale_ttl_secs,
+                    cfg.general.me_secret_atomic_snapshot,
+                    cfg.general.me_deterministic_writer_sort,
+                    cfg.general.me_single_endpoint_shadow_writers,
+                    cfg.general.me_single_endpoint_outage_mode_enabled,
+                    cfg.general.me_single_endpoint_outage_disable_quarantine,
+                    cfg.general.me_single_endpoint_outage_backoff_min_ms,
+                    cfg.general.me_single_endpoint_outage_backoff_max_ms,
+                    cfg.general.me_single_endpoint_shadow_rotate_every_secs,
+                    cfg.general.me_floor_mode,
+                    cfg.general.me_adaptive_floor_idle_secs,
+                    cfg.general.me_adaptive_floor_min_writers_single_endpoint,
+                    cfg.general.me_adaptive_floor_min_writers_multi_endpoint,
+                    cfg.general.me_adaptive_floor_recover_grace_secs,
+                    cfg.general.me_adaptive_floor_writers_per_core_total,
+                    cfg.general.me_adaptive_floor_cpu_cores_override,
+                    cfg.general.me_adaptive_floor_max_extra_writers_single_per_core,
+                    cfg.general.me_adaptive_floor_max_extra_writers_multi_per_core,
+                );
+                let new_secs = cfg.general.effective_update_every_secs().max(1);
+                if new_secs == update_every_secs {
+                    continue;
+                }
 
-        // Update proxy config v6 (optional)
-        let cfg_v6 = retry_fetch("https://core.telegram.org/getProxyConfigV6").await;
-        if let Some(cfg_v6) = cfg_v6 {
-            let changed = pool.update_proxy_maps(HashMap::new(), Some(cfg_v6.map)).await;
-            if changed {
-                info!("ME config updated (v6), reconciling connections");
-                pool.reconcile_connections(&rng).await;
-            } else {
-                debug!("ME config v6 unchanged");
-            }
-        }
-        pool.reset_stun_state();
-
-        // Update proxy-secret
-        match download_proxy_secret().await {
-            Ok(secret) => {
-                if pool.update_secret(secret).await {
-                    info!("proxy-secret updated and pool reconnect scheduled");
+                if new_secs < update_every_secs {
+                    info!(
+                        old_update_every_secs = update_every_secs,
+                        new_update_every_secs = new_secs,
+                        "ME config updater interval decreased, running immediate refresh"
+                    );
+                    update_every_secs = new_secs;
+                    update_every = Duration::from_secs(update_every_secs);
+                    run_update_cycle(&pool, cfg.as_ref(), &mut state, &reinit_tx).await;
+                    next_tick = tokio::time::Instant::now() + update_every;
+                } else {
+                    info!(
+                        old_update_every_secs = update_every_secs,
+                        new_update_every_secs = new_secs,
+                        "ME config updater interval increased"
+                    );
+                    update_every_secs = new_secs;
+                    update_every = Duration::from_secs(update_every_secs);
+                    next_tick = tokio::time::Instant::now() + update_every;
                 }
             }
-            Err(e) => warn!(error = %e, "proxy-secret update failed"),
         }
     }
 }

src/transport/middle_proxy/handshake.rs

@@ -1,5 +1,8 @@
 use std::net::{IpAddr, SocketAddr};
+use std::sync::atomic::Ordering;
 use std::time::{Duration, Instant};
+use std::collections::hash_map::DefaultHasher;
+use std::hash::{Hash, Hasher};
 use socket2::{SockRef, TcpKeepalive};
 #[cfg(target_os = "linux")]
 use libc;
@@ -14,21 +17,43 @@ use tokio::net::{TcpStream, TcpSocket};
 use tokio::time::timeout;
 use tracing::{debug, info, warn};
 
+use crate::config::MeSocksKdfPolicy;
 use crate::crypto::{SecureRandom, build_middleproxy_prekey, derive_middleproxy_keys, sha256};
 use crate::error::{ProxyError, Result};
 use crate::network::IpFamily;
+use crate::network::probe::is_bogon;
 use crate::protocol::constants::{
-    ME_CONNECT_TIMEOUT_SECS, ME_HANDSHAKE_TIMEOUT_SECS, RPC_CRYPTO_AES_U32, RPC_HANDSHAKE_ERROR_U32,
-    RPC_HANDSHAKE_U32, RPC_PING_U32, RPC_PONG_U32, RPC_NONCE_U32,
+    ME_CONNECT_TIMEOUT_SECS, ME_HANDSHAKE_TIMEOUT_SECS, RPC_CRYPTO_AES_U32,
+    RPC_HANDSHAKE_ERROR_U32, rpc_crypto_flags,
 };
+use crate::transport::{UpstreamEgressInfo, UpstreamRouteKind};
 
 use super::codec::{
-    build_handshake_payload, build_nonce_payload, build_rpc_frame, cbc_decrypt_inplace,
-    cbc_encrypt_padded, parse_nonce_payload, read_rpc_frame_plaintext,
+    RpcChecksumMode, build_handshake_payload, build_nonce_payload, build_rpc_frame,
+    cbc_decrypt_inplace, cbc_encrypt_padded, parse_handshake_flags, parse_nonce_payload,
+    read_rpc_frame_plaintext, rpc_crc,
 };
 use super::wire::{extract_ip_material, IpMaterial};
 use super::MePool;
 
+const ME_KDF_DRIFT_STRICT: bool = false;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+enum KdfClientPortSource {
+    LocalSocket = 0,
+    SocksBound = 1,
+}
+
+impl KdfClientPortSource {
+    fn from_socks_bound_port(socks_bound_port: Option<u16>) -> Self {
+        if socks_bound_port.is_some() {
+            Self::SocksBound
+        } else {
+            Self::LocalSocket
+        }
+    }
+}
+
 /// Result of a successful ME handshake with timings.
 pub(crate) struct HandshakeOutput {
     pub rd: ReadHalf<TcpStream>,
@@ -37,16 +62,90 @@ pub(crate) struct HandshakeOutput {
     pub read_iv: [u8; 16],
     pub write_key: [u8; 32],
     pub write_iv: [u8; 16],
+    pub crc_mode: RpcChecksumMode,
     pub handshake_ms: f64,
 }
 
 impl MePool {
+    fn kdf_material_fingerprint(
+        local_ip_nat: IpAddr,
+        peer_addr_nat: SocketAddr,
+        reflected_ip: Option<IpAddr>,
+        socks_bound_ip: Option<IpAddr>,
+        client_port_source: KdfClientPortSource,
+    ) -> u64 {
+        let mut hasher = DefaultHasher::new();
+        local_ip_nat.hash(&mut hasher);
+        peer_addr_nat.hash(&mut hasher);
+        reflected_ip.hash(&mut hasher);
+        socks_bound_ip.hash(&mut hasher);
+        client_port_source.hash(&mut hasher);
+        hasher.finish()
+    }
+
+    async fn resolve_dc_idx_for_endpoint(&self, addr: SocketAddr) -> Option<i16> {
+        i16::try_from(self.resolve_dc_for_endpoint(addr).await).ok()
+    }
+
+    fn direct_bind_ip_for_stun(
+        family: IpFamily,
+        upstream_egress: Option<UpstreamEgressInfo>,
+    ) -> Option<IpAddr> {
+        let info = upstream_egress?;
+        if info.route_kind != UpstreamRouteKind::Direct {
+            return None;
+        }
+        match (family, info.direct_bind_ip) {
+            (IpFamily::V4, Some(IpAddr::V4(ip))) => Some(IpAddr::V4(ip)),
+            (IpFamily::V6, Some(IpAddr::V6(ip))) => Some(IpAddr::V6(ip)),
+            _ => None,
+        }
+    }
+
+    fn select_socks_bound_addr(
+        family: IpFamily,
+        upstream_egress: Option<UpstreamEgressInfo>,
+    ) -> Option<SocketAddr> {
+        let info = upstream_egress?;
+        if !matches!(
+            info.route_kind,
+            UpstreamRouteKind::Socks4 | UpstreamRouteKind::Socks5
+        ) {
+            return None;
+        }
+        let bound = info.socks_bound_addr?;
+        let family_matches = matches!(
+            (family, bound.ip()),
+            (IpFamily::V4, IpAddr::V4(_)) | (IpFamily::V6, IpAddr::V6(_))
+        );
+        if !family_matches || is_bogon(bound.ip()) || bound.ip().is_unspecified() {
+            return None;
+        }
+        Some(bound)
+    }
+
+    fn is_socks_route(upstream_egress: Option<UpstreamEgressInfo>) -> bool {
+        matches!(
+            upstream_egress.map(|info| info.route_kind),
+            Some(UpstreamRouteKind::Socks4 | UpstreamRouteKind::Socks5)
+        )
+    }
+
     /// TCP connect with timeout + return RTT in milliseconds.
-    pub(crate) async fn connect_tcp(&self, addr: SocketAddr) -> Result<(TcpStream, f64)> {
+    pub(crate) async fn connect_tcp(
+        &self,
+        addr: SocketAddr,
+    ) -> Result<(TcpStream, f64, Option<UpstreamEgressInfo>)> {
         let start = Instant::now();
-        let connect_fut = async {
-            if addr.is_ipv6() {
-                if let Some(v6) = self.detected_ipv6 {
+        let (stream, upstream_egress) = if let Some(upstream) = &self.upstream {
+            let dc_idx = self.resolve_dc_idx_for_endpoint(addr).await;
+            let (stream, egress) = upstream.connect_with_details(addr, dc_idx, None).await?;
+            (stream, Some(egress))
+        } else {
+            let connect_fut = async {
+                if addr.is_ipv6()
+                    && let Some(v6) = self.detected_ipv6
+                {
                     match TcpSocket::new_v6() {
                         Ok(sock) => {
                             if let Err(e) = sock.bind(SocketAddr::new(IpAddr::V6(v6), 0)) {
@@ -61,13 +160,17 @@ impl MePool {
                         Err(e) => debug!(error = %e, "ME IPv6 socket creation failed, falling back to default connect"),
                     }
                 }
-            }
-            TcpStream::connect(addr).await
+                TcpStream::connect(addr).await
+            };
+
+            let stream = timeout(Duration::from_secs(ME_CONNECT_TIMEOUT_SECS), connect_fut)
+                .await
+                .map_err(|_| ProxyError::ConnectionTimeout {
+                    addr: addr.to_string(),
+                })??;
+            (stream, None)
         };
 
-        let stream = timeout(Duration::from_secs(ME_CONNECT_TIMEOUT_SECS), connect_fut)
-            .await
-            .map_err(|_| ProxyError::ConnectionTimeout { addr: addr.to_string() })??;
         let connect_ms = start.elapsed().as_secs_f64() * 1000.0;
         stream.set_nodelay(true).ok();
         if let Err(e) = Self::configure_keepalive(&stream) {
@@ -77,7 +180,7 @@ impl MePool {
         if let Err(e) = Self::configure_user_timeout(stream.as_raw_fd()) {
             warn!(error = %e, "ME TCP_USER_TIMEOUT setup failed");
         }
-        Ok((stream, connect_ms))
+        Ok((stream, connect_ms, upstream_egress))
     }
 
     fn configure_keepalive(stream: &TcpStream) -> std::io::Result<()> {
@@ -115,12 +218,14 @@ impl MePool {
         &self,
         stream: TcpStream,
         addr: SocketAddr,
+        upstream_egress: Option<UpstreamEgressInfo>,
         rng: &SecureRandom,
     ) -> Result<HandshakeOutput> {
         let hs_start = Instant::now();
 
         let local_addr = stream.local_addr().map_err(ProxyError::Io)?;
-        let peer_addr = stream.peer_addr().map_err(ProxyError::Io)?;
+        let transport_peer_addr = stream.peer_addr().map_err(ProxyError::Io)?;
+        let peer_addr = addr;
 
         let _ = self.maybe_detect_nat_ip(local_addr.ip()).await;
         let family = if local_addr.ip().is_ipv4() {
@@ -128,8 +233,32 @@ impl MePool {
         } else {
             IpFamily::V6
         };
-        let reflected = if self.nat_probe {
-            self.maybe_reflect_public_addr(family).await
+        let is_socks_route = Self::is_socks_route(upstream_egress);
+        let socks_bound_addr = Self::select_socks_bound_addr(family, upstream_egress);
+        let reflected = if let Some(bound) = socks_bound_addr {
+            Some(bound)
+        } else if is_socks_route {
+            match self.socks_kdf_policy() {
+                MeSocksKdfPolicy::Strict => {
+                    self.stats.increment_me_socks_kdf_strict_reject();
+                    return Err(ProxyError::InvalidHandshake(
+                        "SOCKS route returned no valid BND.ADDR for ME KDF (strict policy)"
+                            .to_string(),
+                    ));
+                }
+                MeSocksKdfPolicy::Compat => {
+                    self.stats.increment_me_socks_kdf_compat_fallback();
+                    if self.nat_probe {
+                        let bind_ip = Self::direct_bind_ip_for_stun(family, upstream_egress);
+                        self.maybe_reflect_public_addr(family, bind_ip).await
+                    } else {
+                        None
+                    }
+                }
+            }
+        } else if self.nat_probe {
+            let bind_ip = Self::direct_bind_ip_for_stun(family, upstream_egress);
+            self.maybe_reflect_public_addr(family, bind_ip).await
         } else {
             None
         };
@@ -144,9 +273,18 @@ impl MePool {
             .unwrap_or_default()
             .as_secs() as u32;
 
-        let ks = self.key_selector().await;
+        let secret_atomic_snapshot = self.secret_atomic_snapshot.load(Ordering::Relaxed);
+        let (ks, secret) = if secret_atomic_snapshot {
+            let snapshot = self.secret_snapshot().await;
+            (snapshot.key_selector, snapshot.secret)
+        } else {
+            // Backward-compatible mode: key selector and secret may come from different updates.
+            let key_selector = self.key_selector().await;
+            let secret = self.secret_snapshot().await.secret;
+            (key_selector, secret)
+        };
         let nonce_payload = build_nonce_payload(ks, crypto_ts, &my_nonce);
-        let nonce_frame = build_rpc_frame(-2, &nonce_payload);
+        let nonce_frame = build_rpc_frame(-2, &nonce_payload, RpcChecksumMode::Crc32);
         let dump = hex_dump(&nonce_frame[..nonce_frame.len().min(44)]);
         debug!(
             key_selector = format_args!("0x{ks:08x}"),
@@ -195,7 +333,9 @@ impl MePool {
             %local_addr_nat,
             reflected_ip = reflected.map(|r| r.ip()).as_ref().map(ToString::to_string),
             %peer_addr,
+            %transport_peer_addr,
             %peer_addr_nat,
+            socks_bound_addr = socks_bound_addr.map(|v| v.to_string()),
             key_selector = format_args!("0x{ks:08x}"),
             crypto_schema = format_args!("0x{schema:08x}"),
             skew_secs = skew,
@@ -204,7 +344,56 @@ impl MePool {
 
         let ts_bytes = crypto_ts.to_le_bytes();
         let server_port_bytes = peer_addr_nat.port().to_le_bytes();
-        let client_port_bytes = local_addr_nat.port().to_le_bytes();
+        let socks_bound_port = socks_bound_addr
+            .map(|bound| bound.port())
+            .filter(|port| *port != 0);
+        let client_port_for_kdf = socks_bound_port.unwrap_or(local_addr_nat.port());
+        let client_port_source = KdfClientPortSource::from_socks_bound_port(socks_bound_port);
+        let kdf_fingerprint = Self::kdf_material_fingerprint(
+            local_addr_nat.ip(),
+            peer_addr_nat,
+            reflected.map(|value| value.ip()),
+            socks_bound_addr.map(|value| value.ip()),
+            client_port_source,
+        );
+        let previous_kdf_fingerprint = {
+            let kdf_fingerprint_guard = self.kdf_material_fingerprint.read().await;
+            kdf_fingerprint_guard.get(&peer_addr_nat).copied()
+        };
+        if let Some((prev_fingerprint, prev_client_port)) = previous_kdf_fingerprint
+        {
+            if prev_fingerprint != kdf_fingerprint {
+                self.stats.increment_me_kdf_drift_total();
+                warn!(
+                    %peer_addr_nat,
+                    %local_addr_nat,
+                    client_port_for_kdf,
+                    client_port_source = ?client_port_source,
+                    "ME KDF material drift detected for endpoint"
+                );
+                if ME_KDF_DRIFT_STRICT {
+                    return Err(ProxyError::InvalidHandshake(
+                        "ME KDF material drift detected (strict mode)".to_string(),
+                    ));
+                }
+            } else if prev_client_port != client_port_for_kdf {
+                self.stats.increment_me_kdf_port_only_drift_total();
+                debug!(
+                    %peer_addr_nat,
+                    previous_client_port_for_kdf = prev_client_port,
+                    client_port_for_kdf,
+                    client_port_source = ?client_port_source,
+                    "ME KDF client port changed with stable material"
+                );
+            }
+        }
+        // Keep fingerprint updates eventually consistent for diagnostics while avoiding
+        // serializing all concurrent handshakes on a single async mutex.
+        let mut kdf_fingerprint_guard = self.kdf_material_fingerprint.write().await;
+        kdf_fingerprint_guard.insert(peer_addr_nat, (kdf_fingerprint, client_port_for_kdf));
+        drop(kdf_fingerprint_guard);
+
+        let client_port_bytes = client_port_for_kdf.to_le_bytes();
 
         let server_ip = extract_ip_material(peer_addr_nat);
         let client_ip = extract_ip_material(local_addr_nat);
@@ -228,8 +417,6 @@ impl MePool {
 
         let diag_level: u8 = std::env::var("ME_DIAG").ok().and_then(|v| v.parse().ok()).unwrap_or(0);
 
-        let secret: Vec<u8> = self.proxy_secret.read().await.clone();
-
         let prekey_client = build_middleproxy_prekey(
             &srv_nonce,
             &my_nonce,
@@ -284,8 +471,15 @@ impl MePool {
             srv_v6_opt.as_ref(),
         );
 
-        let hs_payload = build_handshake_payload(hs_our_ip, local_addr.port(), hs_peer_ip, peer_addr.port());
-        let hs_frame = build_rpc_frame(-1, &hs_payload);
+        let requested_crc_mode = RpcChecksumMode::Crc32c;
+        let hs_payload = build_handshake_payload(
+            hs_our_ip,
+            local_addr.port(),
+            hs_peer_ip,
+            peer_addr.port(),
+            requested_crc_mode.advertised_flags(),
+        );
+        let hs_frame = build_rpc_frame(-1, &hs_payload, RpcChecksumMode::Crc32);
         if diag_level >= 1 {
             info!(
                 write_key = %hex_dump(&wk),
@@ -314,7 +508,7 @@ impl MePool {
             );
         }
 
-        let (encrypted_hs, mut write_iv) = cbc_encrypt_padded(&wk, &wi, &hs_frame)?;
+        let (encrypted_hs, write_iv) = cbc_encrypt_padded(&wk, &wi, &hs_frame)?;
         if diag_level >= 1 {
             info!(
                 hs_cipher = %hex_dump(&encrypted_hs),
@@ -328,6 +522,7 @@ impl MePool {
         let mut enc_buf = BytesMut::with_capacity(256);
         let mut dec_buf = BytesMut::with_capacity(256);
         let mut read_iv = ri;
+        let mut negotiated_crc_mode = RpcChecksumMode::Crc32;
         let mut handshake_ok = false;
 
         while Instant::now() < deadline && !handshake_ok {
@@ -375,29 +570,47 @@ impl MePool {
                 let frame = dec_buf.split_to(fl);
                 let pe = fl - 4;
                 let ec = u32::from_le_bytes(frame[pe..pe + 4].try_into().unwrap());
-                let ac = crate::crypto::crc32(&frame[..pe]);
+                let ac = rpc_crc(RpcChecksumMode::Crc32, &frame[..pe]);
                 if ec != ac {
                     return Err(ProxyError::InvalidHandshake(format!(
                         "HS CRC mismatch: 0x{ec:08x} vs 0x{ac:08x}"
                     )));
                 }
 
-                let hs_type = u32::from_le_bytes(frame[8..12].try_into().unwrap());
+                let hs_payload = &frame[8..pe];
+                if hs_payload.len() < 4 {
+                    return Err(ProxyError::InvalidHandshake(
+                        "Handshake payload too short".to_string(),
+                    ));
+                }
+                let hs_type = u32::from_le_bytes(hs_payload[0..4].try_into().unwrap());
                 if hs_type == RPC_HANDSHAKE_ERROR_U32 {
-                    let err_code = if frame.len() >= 16 {
-                        i32::from_le_bytes(frame[12..16].try_into().unwrap())
+                    let err_code = if hs_payload.len() >= 8 {
+                        i32::from_le_bytes(hs_payload[4..8].try_into().unwrap())
                     } else {
                         -1
                     };
+                    self.stats.increment_me_handshake_reject_total();
+                    self.stats.increment_me_handshake_error_code(err_code);
                     return Err(ProxyError::InvalidHandshake(format!(
                         "ME rejected handshake (error={err_code})"
                     )));
                 }
-                if hs_type != RPC_HANDSHAKE_U32 {
+                let hs_flags = parse_handshake_flags(hs_payload)?;
+                if hs_flags & 0xff != 0 {
                     return Err(ProxyError::InvalidHandshake(format!(
-                        "Expected HANDSHAKE 0x{RPC_HANDSHAKE_U32:08x}, got 0x{hs_type:08x}"
+                        "Unsupported handshake flags: 0x{hs_flags:08x}"
                     )));
                 }
+                negotiated_crc_mode = if (hs_flags & requested_crc_mode.advertised_flags()) != 0 {
+                    RpcChecksumMode::from_handshake_flags(hs_flags)
+                } else if (hs_flags & rpc_crypto_flags::USE_CRC32C) != 0 {
+                    return Err(ProxyError::InvalidHandshake(format!(
+                        "Peer negotiated unsupported CRC flags: 0x{hs_flags:08x}"
+                    )));
+                } else {
+                    RpcChecksumMode::Crc32
+                };
 
                 handshake_ok = true;
                 break;
@@ -418,6 +631,7 @@ impl MePool {
             read_iv,
             write_key: wk,
             write_iv,
+            crc_mode: negotiated_crc_mode,
             handshake_ms,
         })
     }

src/transport/middle_proxy/mod.rs

@@ -1,29 +1,42 @@
 //! Middle Proxy RPC transport.
 
 mod codec;
+mod config_updater;
 mod handshake;
 mod health;
 mod pool;
+mod pool_config;
+mod pool_init;
 mod pool_nat;
+mod pool_refill;
+mod pool_reinit;
+mod pool_runtime_api;
+mod pool_writer;
 mod ping;
 mod reader;
 mod registry;
+mod rotation;
 mod send;
 mod secret;
-mod rotation;
-mod config_updater;
 mod wire;
+mod pool_status;
 
 use bytes::Bytes;
 
 pub use health::me_health_monitor;
-pub use ping::{run_me_ping, format_sample_line, MePingReport, MePingSample, MePingFamily};
+#[allow(unused_imports)]
+pub use ping::{run_me_ping, format_sample_line, format_me_route, MePingReport, MePingSample, MePingFamily};
 pub use pool::MePool;
+#[allow(unused_imports)]
 pub use pool_nat::{stun_probe, detect_public_ip};
 pub use registry::ConnRegistry;
 pub use secret::fetch_proxy_secret;
-pub use config_updater::{fetch_proxy_config, me_config_updater};
-pub use rotation::me_rotation_task;
+#[allow(unused_imports)]
+pub use config_updater::{
+    ProxyConfigData, fetch_proxy_config, fetch_proxy_config_with_raw, load_proxy_config_cache,
+    me_config_updater, save_proxy_config_cache,
+};
+pub use rotation::{MeReinitTrigger, me_reinit_scheduler, me_rotation_task};
 pub use wire::proto_flags_for_tag;
 
 #[derive(Debug)]

src/transport/middle_proxy/ping.rs

@@ -2,8 +2,12 @@ use std::collections::HashMap;
 use std::net::{IpAddr, SocketAddr};
 use std::sync::Arc;
 
+use tokio::net::UdpSocket;
+
+use crate::config::{UpstreamConfig, UpstreamType};
 use crate::crypto::SecureRandom;
 use crate::error::ProxyError;
+use crate::transport::{UpstreamEgressInfo, UpstreamRouteKind};
 
 use super::MePool;
 
@@ -17,6 +21,7 @@ pub enum MePingFamily {
 pub struct MePingSample {
     pub dc: i32,
     pub addr: SocketAddr,
+    pub route: Option<String>,
     pub connect_ms: Option<f64>,
     pub handshake_ms: Option<f64>,
     pub error: Option<String>,
@@ -24,6 +29,7 @@ pub struct MePingSample {
 }
 
 #[derive(Debug, Clone)]
+#[allow(dead_code)]
 pub struct MePingReport {
     pub dc: i32,
     pub family: MePingFamily,
@@ -49,6 +55,208 @@ pub fn format_sample_line(sample: &MePingSample) -> String {
     }
 }
 
+fn format_direct_with_config(
+    interface: &Option<String>,
+    bind_addresses: &Option<Vec<String>>,
+) -> Option<String> {
+    let mut direct_parts: Vec<String> = Vec::new();
+    if let Some(dev) = interface.as_deref().filter(|v| !v.is_empty()) {
+        direct_parts.push(format!("dev={dev}"));
+    }
+    if let Some(src) = bind_addresses.as_ref().filter(|v| !v.is_empty()) {
+        direct_parts.push(format!("src={}", src.join(",")));
+    }
+    if direct_parts.is_empty() {
+        None
+    } else {
+        Some(format!("direct {}", direct_parts.join(" ")))
+    }
+}
+
+fn pick_target_for_family(reports: &[MePingReport], family: MePingFamily) -> Option<SocketAddr> {
+    reports.iter().find_map(|report| {
+        if report.family != family {
+            return None;
+        }
+        report
+            .samples
+            .iter()
+            .find(|s| s.error.is_none() && s.handshake_ms.is_some())
+            .map(|s| s.addr)
+    })
+}
+
+fn route_from_egress(egress: Option<UpstreamEgressInfo>) -> Option<String> {
+    let info = egress?;
+    match info.route_kind {
+        UpstreamRouteKind::Direct => {
+            let src_ip = info
+                .direct_bind_ip
+                .or_else(|| info.local_addr.map(|addr| addr.ip()));
+            let ip = src_ip?;
+            let mut parts = Vec::new();
+            if let Some(dev) = detect_interface_for_ip(ip) {
+                parts.push(format!("dev={dev}"));
+            }
+            parts.push(format!("src={ip}"));
+            Some(format!("direct {}", parts.join(" ")))
+        }
+        UpstreamRouteKind::Socks4 => {
+            let route = info
+                .socks_proxy_addr
+                .map(|addr| format!("socks4://{addr}"))
+                .unwrap_or_else(|| "socks4://unknown".to_string());
+            Some(match info.socks_bound_addr {
+                Some(bound) => format!("{route} bnd={bound}"),
+                None => route,
+            })
+        }
+        UpstreamRouteKind::Socks5 => {
+            let route = info
+                .socks_proxy_addr
+                .map(|addr| format!("socks5://{addr}"))
+                .unwrap_or_else(|| "socks5://unknown".to_string());
+            Some(match info.socks_bound_addr {
+                Some(bound) => format!("{route} bnd={bound}"),
+                None => route,
+            })
+        }
+    }
+}
+
+#[cfg(unix)]
+fn detect_interface_for_ip(ip: IpAddr) -> Option<String> {
+    use nix::ifaddrs::getifaddrs;
+
+    if let Ok(addrs) = getifaddrs() {
+        for iface in addrs {
+            if let Some(address) = iface.address {
+                if let Some(v4) = address.as_sockaddr_in() {
+                    if IpAddr::V4(v4.ip()) == ip {
+                        return Some(iface.interface_name);
+                    }
+                } else if let Some(v6) = address.as_sockaddr_in6() {
+                    if IpAddr::V6(v6.ip()) == ip {
+                        return Some(iface.interface_name);
+                    }
+                }
+            }
+        }
+    }
+    None
+}
+
+#[cfg(not(unix))]
+fn detect_interface_for_ip(_ip: IpAddr) -> Option<String> {
+    None
+}
+
+async fn detect_direct_route_details(
+    reports: &[MePingReport],
+    prefer_ipv6: bool,
+    v4_ok: bool,
+    v6_ok: bool,
+) -> Option<String> {
+    let target_addr = if prefer_ipv6 && v6_ok {
+        pick_target_for_family(reports, MePingFamily::V6)
+            .or_else(|| pick_target_for_family(reports, MePingFamily::V4))
+    } else if v4_ok {
+        pick_target_for_family(reports, MePingFamily::V4)
+            .or_else(|| pick_target_for_family(reports, MePingFamily::V6))
+    } else {
+        pick_target_for_family(reports, MePingFamily::V6)
+            .or_else(|| pick_target_for_family(reports, MePingFamily::V4))
+    }?;
+
+    let local_ip = if target_addr.is_ipv4() {
+        let sock = UdpSocket::bind("0.0.0.0:0").await.ok()?;
+        sock.connect(target_addr).await.ok()?;
+        sock.local_addr().ok().map(|a| a.ip())
+    } else {
+        let sock = UdpSocket::bind("[::]:0").await.ok()?;
+        sock.connect(target_addr).await.ok()?;
+        sock.local_addr().ok().map(|a| a.ip())
+    };
+
+    let mut parts = Vec::new();
+    if let Some(ip) = local_ip {
+        if let Some(dev) = detect_interface_for_ip(ip) {
+            parts.push(format!("dev={dev}"));
+        }
+        parts.push(format!("src={ip}"));
+    }
+
+    if parts.is_empty() {
+        None
+    } else {
+        Some(format!("direct {}", parts.join(" ")))
+    }
+}
+
+pub async fn format_me_route(
+    upstreams: &[UpstreamConfig],
+    reports: &[MePingReport],
+    prefer_ipv6: bool,
+    v4_ok: bool,
+    v6_ok: bool,
+) -> String {
+    if let Some(route) = reports
+        .iter()
+        .flat_map(|report| report.samples.iter())
+        .find(|sample| sample.error.is_none() && sample.handshake_ms.is_some())
+        .and_then(|sample| sample.route.clone())
+    {
+        return route;
+    }
+
+    let enabled_upstreams: Vec<_> = upstreams.iter().filter(|u| u.enabled).collect();
+    if enabled_upstreams.is_empty() {
+        return detect_direct_route_details(reports, prefer_ipv6, v4_ok, v6_ok)
+            .await
+            .unwrap_or_else(|| "direct".to_string());
+    }
+
+    if enabled_upstreams.len() == 1 {
+        return match &enabled_upstreams[0].upstream_type {
+            UpstreamType::Direct {
+                interface,
+                bind_addresses,
+            } => {
+                if let Some(route) = format_direct_with_config(interface, bind_addresses) {
+                    route
+                } else {
+                    detect_direct_route_details(reports, prefer_ipv6, v4_ok, v6_ok)
+                        .await
+                        .unwrap_or_else(|| "direct".to_string())
+                }
+            }
+            UpstreamType::Socks4 { address, .. } => format!("socks4://{address}"),
+            UpstreamType::Socks5 { address, .. } => format!("socks5://{address}"),
+        };
+    }
+
+    let has_direct = enabled_upstreams
+        .iter()
+        .any(|u| matches!(u.upstream_type, UpstreamType::Direct { .. }));
+    let has_socks4 = enabled_upstreams
+        .iter()
+        .any(|u| matches!(u.upstream_type, UpstreamType::Socks4 { .. }));
+    let has_socks5 = enabled_upstreams
+        .iter()
+        .any(|u| matches!(u.upstream_type, UpstreamType::Socks5 { .. }));
+    let mut kinds = Vec::new();
+    if has_direct {
+        kinds.push("direct");
+    }
+    if has_socks4 {
+        kinds.push("socks4");
+    }
+    if has_socks5 {
+        kinds.push("socks5");
+    }
+    format!("mixed upstreams ({})", kinds.join(", "))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -63,6 +271,7 @@ mod tests {
         let s = sample(MePingSample {
             dc: 4,
             addr: SocketAddr::new(IpAddr::V4(Ipv4Addr::new(1, 2, 3, 4)), 8888),
+            route: Some("direct src=1.2.3.4".to_string()),
             connect_ms: Some(12.3),
             handshake_ms: Some(34.7),
             error: None,
@@ -79,6 +288,7 @@ mod tests {
         let s = sample(MePingSample {
             dc: -5,
             addr: SocketAddr::new(IpAddr::V4(Ipv4Addr::new(5, 6, 7, 8)), 80),
+            route: Some("socks5".to_string()),
             connect_ms: Some(10.0),
             handshake_ms: None,
             error: Some("handshake timeout".to_string()),
@@ -119,11 +329,13 @@ pub async fn run_me_ping(pool: &Arc<MePool>, rng: &SecureRandom) -> Vec<MePingRe
             let mut connect_ms = None;
             let mut handshake_ms = None;
             let mut error = None;
+            let mut route = None;
 
             match pool.connect_tcp(addr).await {
-                Ok((stream, conn_rtt)) => {
+                Ok((stream, conn_rtt, upstream_egress)) => {
                     connect_ms = Some(conn_rtt);
-                    match pool.handshake_only(stream, addr, rng).await {
+                    route = route_from_egress(upstream_egress);
+                    match pool.handshake_only(stream, addr, upstream_egress, rng).await {
                         Ok(hs) => {
                             handshake_ms = Some(hs.handshake_ms);
                             // drop halves to close
@@ -143,6 +355,7 @@ pub async fn run_me_ping(pool: &Arc<MePool>, rng: &SecureRandom) -> Vec<MePingRe
             samples.push(MePingSample {
                 dc,
                 addr,
+                route,
                 connect_ms,
                 handshake_ms,
                 error,

src/transport/middle_proxy/pool_config.rs

@@ -0,0 +1,119 @@
+use std::collections::HashMap;
+use std::net::IpAddr;
+use std::sync::Arc;
+use std::time::Duration;
+
+use tracing::warn;
+
+use super::pool::MePool;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum SnapshotApplyOutcome {
+    AppliedChanged,
+    AppliedNoDelta,
+    RejectedEmpty,
+}
+
+impl SnapshotApplyOutcome {
+    pub fn changed(self) -> bool {
+        matches!(self, SnapshotApplyOutcome::AppliedChanged)
+    }
+}
+
+impl MePool {
+    pub async fn update_proxy_maps(
+        &self,
+        new_v4: HashMap<i32, Vec<(IpAddr, u16)>>,
+        new_v6: Option<HashMap<i32, Vec<(IpAddr, u16)>>>,
+    ) -> SnapshotApplyOutcome {
+        if new_v4.is_empty() && new_v6.as_ref().is_none_or(|v| v.is_empty()) {
+            return SnapshotApplyOutcome::RejectedEmpty;
+        }
+
+        let mut changed = false;
+        {
+            let mut guard = self.proxy_map_v4.write().await;
+            if !new_v4.is_empty() && *guard != new_v4 {
+                *guard = new_v4;
+                changed = true;
+            }
+        }
+        if let Some(v6) = new_v6 {
+            let mut guard = self.proxy_map_v6.write().await;
+            if !v6.is_empty() && *guard != v6 {
+                *guard = v6;
+                changed = true;
+            }
+        }
+        // Ensure negative DC entries mirror positives when absent (Telegram convention).
+        {
+            let mut guard = self.proxy_map_v4.write().await;
+            let keys: Vec<i32> = guard.keys().cloned().collect();
+            for k in keys.iter().cloned().filter(|k| *k > 0) {
+                if !guard.contains_key(&-k)
+                    && let Some(addrs) = guard.get(&k).cloned()
+                {
+                    guard.insert(-k, addrs);
+                    changed = true;
+                }
+            }
+        }
+        {
+            let mut guard = self.proxy_map_v6.write().await;
+            let keys: Vec<i32> = guard.keys().cloned().collect();
+            for k in keys.iter().cloned().filter(|k| *k > 0) {
+                if !guard.contains_key(&-k)
+                    && let Some(addrs) = guard.get(&k).cloned()
+                {
+                    guard.insert(-k, addrs);
+                    changed = true;
+                }
+            }
+        }
+        if changed {
+            self.rebuild_endpoint_dc_map().await;
+            self.writer_available.notify_waiters();
+        }
+        if changed {
+            SnapshotApplyOutcome::AppliedChanged
+        } else {
+            SnapshotApplyOutcome::AppliedNoDelta
+        }
+    }
+
+    pub async fn update_secret(self: &Arc<Self>, new_secret: Vec<u8>) -> bool {
+        if new_secret.len() < 32 {
+            warn!(len = new_secret.len(), "proxy-secret update ignored (too short)");
+            return false;
+        }
+        let mut guard = self.proxy_secret.write().await;
+        if guard.secret != new_secret {
+            guard.secret = new_secret;
+            guard.key_selector = if guard.secret.len() >= 4 {
+                u32::from_le_bytes([
+                    guard.secret[0],
+                    guard.secret[1],
+                    guard.secret[2],
+                    guard.secret[3],
+                ])
+            } else {
+                0
+            };
+            guard.epoch = guard.epoch.saturating_add(1);
+            drop(guard);
+            self.reconnect_all().await;
+            return true;
+        }
+        false
+    }
+
+    pub async fn reconnect_all(self: &Arc<Self>) {
+        let ws = self.writers.read().await.clone();
+        for w in ws {
+            if let Ok(()) = self.connect_one(w.addr, self.rng.as_ref()).await {
+                self.mark_writer_draining(w.id).await;
+                tokio::time::sleep(Duration::from_secs(2)).await;
+            }
+        }
+    }
+}

src/transport/middle_proxy/pool_init.rs

@@ -0,0 +1,224 @@
+use std::collections::HashSet;
+use std::net::{IpAddr, SocketAddr};
+use std::sync::Arc;
+
+use rand::Rng;
+use rand::seq::SliceRandom;
+use tracing::{debug, info, warn};
+
+use crate::crypto::SecureRandom;
+use crate::error::{ProxyError, Result};
+
+use super::pool::MePool;
+
+impl MePool {
+    pub async fn init(self: &Arc<Self>, pool_size: usize, rng: &Arc<SecureRandom>) -> Result<()> {
+        let family_order = self.family_order();
+        let connect_concurrency = self.me_reconnect_max_concurrent_per_dc.max(1) as usize;
+        let ks = self.key_selector().await;
+        info!(
+            me_servers = self.proxy_map_v4.read().await.len(),
+            pool_size,
+            connect_concurrency,
+            key_selector = format_args!("0x{ks:08x}"),
+            secret_len = self.proxy_secret.read().await.secret.len(),
+            "Initializing ME pool"
+        );
+
+        for family in family_order {
+            let map = self.proxy_map_for_family(family).await;
+            let mut dc_addrs: Vec<(i32, Vec<(IpAddr, u16)>)> = map
+                .into_iter()
+                .map(|(dc, mut addrs)| {
+                    addrs.sort_unstable();
+                    addrs.dedup();
+                    (dc, addrs)
+                })
+                .filter(|(_, addrs)| !addrs.is_empty())
+                .collect();
+            dc_addrs.sort_unstable_by_key(|(dc, _)| *dc);
+            dc_addrs.sort_by_key(|(_, addrs)| (addrs.len() != 1, addrs.len()));
+
+            // Stage 1: build base coverage for conditional-cast.
+            // Single-endpoint DCs are prefilled first; multi-endpoint DCs require one live writer.
+            let mut join = tokio::task::JoinSet::new();
+            for (dc, addrs) in dc_addrs.iter().cloned() {
+                if addrs.is_empty() {
+                    continue;
+                }
+                let target_writers = if addrs.len() == 1 {
+                    self.required_writers_for_dc_with_floor_mode(addrs.len(), false)
+                } else {
+                    1usize
+                };
+                let endpoints: HashSet<SocketAddr> = addrs
+                    .iter()
+                    .map(|(ip, port)| SocketAddr::new(*ip, *port))
+                    .collect();
+                if self.active_writer_count_for_endpoints(&endpoints).await >= target_writers {
+                    continue;
+                }
+                let pool = Arc::clone(self);
+                let rng_clone = Arc::clone(rng);
+                join.spawn(async move {
+                    pool.connect_primary_for_dc(
+                        dc,
+                        addrs,
+                        target_writers,
+                        rng_clone,
+                        connect_concurrency,
+                    )
+                    .await
+                });
+            }
+            while join.join_next().await.is_some() {}
+
+            let mut missing_dcs = Vec::new();
+            for (dc, addrs) in &dc_addrs {
+                let endpoints: HashSet<SocketAddr> = addrs
+                    .iter()
+                    .map(|(ip, port)| SocketAddr::new(*ip, *port))
+                    .collect();
+                if self.active_writer_count_for_endpoints(&endpoints).await == 0 {
+                    missing_dcs.push(*dc);
+                }
+            }
+            if !missing_dcs.is_empty() {
+                return Err(ProxyError::Proxy(format!(
+                    "ME init incomplete: no live writers for DC groups {missing_dcs:?}"
+                )));
+            }
+
+            // Stage 2: continue saturating multi-endpoint DC groups in background.
+            let pool = Arc::clone(self);
+            let rng_clone = Arc::clone(rng);
+            let dc_addrs_bg = dc_addrs.clone();
+            tokio::spawn(async move {
+                let mut join_bg = tokio::task::JoinSet::new();
+                for (dc, addrs) in dc_addrs_bg {
+                    if addrs.len() <= 1 {
+                        continue;
+                    }
+                    let target_writers = pool.required_writers_for_dc_with_floor_mode(addrs.len(), false);
+                    let pool_clone = Arc::clone(&pool);
+                    let rng_clone_local = Arc::clone(&rng_clone);
+                    join_bg.spawn(async move {
+                        pool_clone
+                            .connect_primary_for_dc(
+                                dc,
+                                addrs,
+                                target_writers,
+                                rng_clone_local,
+                                connect_concurrency,
+                            )
+                            .await
+                    });
+                }
+                while join_bg.join_next().await.is_some() {}
+                debug!(
+                    current_pool_size = pool.connection_count(),
+                    "Background ME saturation warmup finished"
+                );
+            });
+
+            if !self.decision.effective_multipath && self.connection_count() > 0 {
+                break;
+            }
+        }
+
+        if self.writers.read().await.is_empty() {
+            return Err(ProxyError::Proxy("No ME connections".into()));
+        }
+        info!(
+            active_writers = self.connection_count(),
+            "ME primary pool ready; reserve warmup continues in background"
+        );
+        Ok(())
+    }
+
+    async fn connect_primary_for_dc(
+        self: Arc<Self>,
+        dc: i32,
+        mut addrs: Vec<(IpAddr, u16)>,
+        target_writers: usize,
+        rng: Arc<SecureRandom>,
+        connect_concurrency: usize,
+    ) -> bool {
+        if addrs.is_empty() {
+            return false;
+        }
+        let target_writers = target_writers.max(1);
+        addrs.shuffle(&mut rand::rng());
+        let endpoints: Vec<SocketAddr> = addrs
+            .iter()
+            .map(|(ip, port)| SocketAddr::new(*ip, *port))
+            .collect();
+        let endpoint_set: HashSet<SocketAddr> = endpoints.iter().copied().collect();
+
+        loop {
+            let alive = self.active_writer_count_for_endpoints(&endpoint_set).await;
+            if alive >= target_writers {
+                info!(
+                    dc = %dc,
+                    alive,
+                    target_writers,
+                    "ME connected"
+                );
+                return true;
+            }
+
+            let missing = target_writers.saturating_sub(alive).max(1);
+            let concurrency = connect_concurrency.max(1).min(missing);
+            let mut join = tokio::task::JoinSet::new();
+            for _ in 0..concurrency {
+                let pool = Arc::clone(&self);
+                let rng_clone = Arc::clone(&rng);
+                let endpoints_clone = endpoints.clone();
+                join.spawn(async move {
+                    pool.connect_endpoints_round_robin(&endpoints_clone, rng_clone.as_ref())
+                        .await
+                });
+            }
+
+            let mut progress = false;
+            while let Some(res) = join.join_next().await {
+                match res {
+                    Ok(true) => {
+                        progress = true;
+                    }
+                    Ok(false) => {}
+                    Err(e) => {
+                        warn!(dc = %dc, error = %e, "ME connect task failed");
+                    }
+                }
+            }
+
+            let alive_after = self.active_writer_count_for_endpoints(&endpoint_set).await;
+            if alive_after >= target_writers {
+                info!(
+                    dc = %dc,
+                    alive = alive_after,
+                    target_writers,
+                    "ME connected"
+                );
+                return true;
+            }
+            if !progress {
+                warn!(
+                    dc = %dc,
+                    alive = alive_after,
+                    target_writers,
+                    "All ME servers for DC failed at init"
+                );
+                return false;
+            }
+
+            if self.me_warmup_stagger_enabled {
+                let jitter = rand::rng()
+                    .random_range(0..=self.me_warmup_step_jitter.as_millis() as u64);
+                let delay_ms = self.me_warmup_step_delay.as_millis() as u64 + jitter;
+                tokio::time::sleep(std::time::Duration::from_millis(delay_ms)).await;
+            }
+        }
+    }
+}

src/transport/middle_proxy/pool_nat.rs

@@ -1,28 +1,139 @@
+use std::collections::HashMap;
 use std::net::{IpAddr, Ipv4Addr};
 use std::time::Duration;
 
-use tracing::{info, warn, debug};
+use tokio::task::JoinSet;
+use tokio::time::timeout;
+use tracing::{debug, info, warn};
 
 use crate::error::{ProxyError, Result};
 use crate::network::probe::is_bogon;
-use crate::network::stun::{stun_probe_dual, IpFamily, StunProbeResult};
+use crate::network::stun::{stun_probe_dual, stun_probe_family_with_bind, IpFamily};
 
 use super::MePool;
 use std::time::Instant;
+
+const STUN_BATCH_TIMEOUT: Duration = Duration::from_secs(5);
+
+#[allow(dead_code)]
 pub async fn stun_probe(stun_addr: Option<String>) -> Result<crate::network::stun::DualStunResult> {
-    let stun_addr = stun_addr.unwrap_or_else(|| "stun.l.google.com:19302".to_string());
+    let stun_addr = stun_addr.unwrap_or_else(|| {
+        crate::config::defaults::default_stun_servers()
+            .into_iter()
+            .next()
+            .unwrap_or_default()
+    });
+    if stun_addr.is_empty() {
+        return Err(ProxyError::Proxy("STUN server is not configured".to_string()));
+    }
     stun_probe_dual(&stun_addr).await
 }
 
+#[allow(dead_code)]
 pub async fn detect_public_ip() -> Option<IpAddr> {
     fetch_public_ipv4_with_retry().await.ok().flatten().map(IpAddr::V4)
 }
 
 impl MePool {
+    fn configured_stun_servers(&self) -> Vec<String> {
+        if !self.nat_stun_servers.is_empty() {
+            return self.nat_stun_servers.clone();
+        }
+        if let Some(s) = &self.nat_stun
+            && !s.trim().is_empty()
+        {
+            return vec![s.clone()];
+        }
+        Vec::new()
+    }
+
+    async fn probe_stun_batch_for_family(
+        &self,
+        servers: &[String],
+        family: IpFamily,
+        attempt: u8,
+        bind_ip: Option<IpAddr>,
+    ) -> (Vec<String>, Option<std::net::SocketAddr>) {
+        let mut join_set = JoinSet::new();
+        let mut next_idx = 0usize;
+        let mut live_servers = Vec::new();
+        let mut best_by_ip: HashMap<IpAddr, (usize, std::net::SocketAddr)> = HashMap::new();
+        let concurrency = self.nat_probe_concurrency.max(1);
+
+        while next_idx < servers.len() || !join_set.is_empty() {
+            while next_idx < servers.len() && join_set.len() < concurrency {
+                let stun_addr = servers[next_idx].clone();
+                next_idx += 1;
+                join_set.spawn(async move {
+                    let res = timeout(
+                        STUN_BATCH_TIMEOUT,
+                        stun_probe_family_with_bind(&stun_addr, family, bind_ip),
+                    )
+                    .await;
+                    (stun_addr, res)
+                });
+            }
+
+            let Some(task) = join_set.join_next().await else {
+                break;
+            };
+
+            match task {
+                Ok((stun_addr, Ok(Ok(picked)))) => {
+                    if let Some(result) = picked {
+                        live_servers.push(stun_addr.clone());
+                        let entry = best_by_ip
+                            .entry(result.reflected_addr.ip())
+                            .or_insert((0, result.reflected_addr));
+                        entry.0 += 1;
+                        debug!(
+                            local = %result.local_addr,
+                            reflected = %result.reflected_addr,
+                            family = ?family,
+                            stun = %stun_addr,
+                            "NAT probe: reflected address"
+                        );
+                    }
+                }
+                Ok((stun_addr, Ok(Err(e)))) => {
+                    debug!(
+                        error = %e,
+                        stun = %stun_addr,
+                        attempt = attempt + 1,
+                        "NAT probe failed, trying next server"
+                    );
+                }
+                Ok((stun_addr, Err(_))) => {
+                    debug!(
+                        stun = %stun_addr,
+                        attempt = attempt + 1,
+                        "NAT probe timeout, trying next server"
+                    );
+                }
+                Err(e) => {
+                    debug!(
+                        error = %e,
+                        attempt = attempt + 1,
+                        "NAT probe task join failed"
+                    );
+                }
+            }
+        }
+
+        live_servers.sort_unstable();
+        live_servers.dedup();
+        let best_reflected = best_by_ip
+            .into_values()
+            .max_by_key(|(count, _)| *count)
+            .map(|(_, addr)| addr);
+
+        (live_servers, best_reflected)
+    }
+
     pub(super) fn translate_ip_for_nat(&self, ip: IpAddr) -> IpAddr {
         let nat_ip = self
             .nat_ip_cfg
-            .or_else(|| self.nat_ip_detected.try_read().ok().and_then(|g| (*g).clone()));
+            .or_else(|| self.nat_ip_detected.try_read().ok().and_then(|g| *g));
 
         let Some(nat_ip) = nat_ip else {
             return ip;
@@ -72,7 +183,7 @@ impl MePool {
             return None;
         }
 
-        if let Some(ip) = self.nat_ip_detected.read().await.clone() {
+        if let Some(ip) = *self.nat_ip_detected.read().await {
             return Some(ip);
         }
 
@@ -96,70 +207,142 @@ impl MePool {
     pub(super) async fn maybe_reflect_public_addr(
         &self,
         family: IpFamily,
+        bind_ip: Option<IpAddr>,
     ) -> Option<std::net::SocketAddr> {
         const STUN_CACHE_TTL: Duration = Duration::from_secs(600);
-        // Backoff window
-        if let Some(until) = *self.stun_backoff_until.read().await {
-            if Instant::now() < until {
-                if let Ok(cache) = self.nat_reflection_cache.try_lock() {
-                    let slot = match family {
-                        IpFamily::V4 => cache.v4,
-                        IpFamily::V6 => cache.v6,
-                    };
-                    return slot.map(|(_, addr)| addr);
-                }
-                return None;
+        let use_shared_cache = bind_ip.is_none();
+        if !use_shared_cache {
+            match (family, bind_ip) {
+                (IpFamily::V4, Some(IpAddr::V4(_)))
+                | (IpFamily::V6, Some(IpAddr::V6(_)))
+                | (_, None) => {}
+                _ => return None,
             }
         }
+        // Backoff window
+        if use_shared_cache
+            && let Some(until) = *self.stun_backoff_until.read().await
+            && Instant::now() < until
+        {
+            if let Ok(cache) = self.nat_reflection_cache.try_lock() {
+                let slot = match family {
+                    IpFamily::V4 => cache.v4,
+                    IpFamily::V6 => cache.v6,
+                };
+                return slot.map(|(_, addr)| addr);
+            }
+            return None;
+        }
 
-        if let Ok(mut cache) = self.nat_reflection_cache.try_lock() {
+        if use_shared_cache
+            && let Ok(mut cache) = self.nat_reflection_cache.try_lock()
+        {
             let slot = match family {
                 IpFamily::V4 => &mut cache.v4,
                 IpFamily::V6 => &mut cache.v6,
             };
-            if let Some((ts, addr)) = slot {
-                if ts.elapsed() < STUN_CACHE_TTL {
-                    return Some(*addr);
-                }
+            if let Some((ts, addr)) = slot
+                && ts.elapsed() < STUN_CACHE_TTL
+            {
+                return Some(*addr);
             }
         }
 
-        let attempt = self.nat_probe_attempts.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
-        let servers = if !self.nat_stun_servers.is_empty() {
-            self.nat_stun_servers.clone()
-        } else if let Some(s) = &self.nat_stun {
-            vec![s.clone()]
+        let _singleflight_guard = if use_shared_cache {
+            Some(match family {
+                IpFamily::V4 => self.nat_reflection_singleflight_v4.lock().await,
+                IpFamily::V6 => self.nat_reflection_singleflight_v6.lock().await,
+            })
         } else {
-            vec!["stun.l.google.com:19302".to_string()]
+            None
         };
 
-        for stun_addr in servers {
-            match stun_probe_dual(&stun_addr).await {
-                Ok(res) => {
-                    let picked: Option<StunProbeResult> = match family {
-                        IpFamily::V4 => res.v4,
-                        IpFamily::V6 => res.v6,
-                    };
-                    if let Some(result) = picked {
-                        info!(local = %result.local_addr, reflected = %result.reflected_addr, family = ?family, stun = %stun_addr, "NAT probe: reflected address");
-                        self.nat_probe_attempts.store(0, std::sync::atomic::Ordering::Relaxed);
-                        if let Ok(mut cache) = self.nat_reflection_cache.try_lock() {
-                            let slot = match family {
-                                IpFamily::V4 => &mut cache.v4,
-                                IpFamily::V6 => &mut cache.v6,
-                            };
-                            *slot = Some((Instant::now(), result.reflected_addr));
-                        }
-                        return Some(result.reflected_addr);
-                    }
-                }
-                Err(e) => {
-                    warn!(error = %e, stun = %stun_addr, attempt = attempt + 1, "NAT probe failed, trying next server");
-                }
+        if use_shared_cache
+            && let Some(until) = *self.stun_backoff_until.read().await
+            && Instant::now() < until
+        {
+            if let Ok(cache) = self.nat_reflection_cache.try_lock() {
+                let slot = match family {
+                    IpFamily::V4 => cache.v4,
+                    IpFamily::V6 => cache.v6,
+                };
+                return slot.map(|(_, addr)| addr);
+            }
+            return None;
+        }
+
+        if use_shared_cache
+            && let Ok(mut cache) = self.nat_reflection_cache.try_lock()
+        {
+            let slot = match family {
+                IpFamily::V4 => &mut cache.v4,
+                IpFamily::V6 => &mut cache.v6,
+            };
+            if let Some((ts, addr)) = slot
+                && ts.elapsed() < STUN_CACHE_TTL
+            {
+                return Some(*addr);
             }
         }
-        let backoff = Duration::from_secs(60 * 2u64.pow((attempt as u32).min(6)));
-        *self.stun_backoff_until.write().await = Some(Instant::now() + backoff);
+
+        let attempt = if use_shared_cache {
+            self.nat_probe_attempts.fetch_add(1, std::sync::atomic::Ordering::Relaxed)
+        } else {
+            0
+        };
+        let configured_servers = self.configured_stun_servers();
+        let live_snapshot = self.nat_stun_live_servers.read().await.clone();
+        let primary_servers = if live_snapshot.is_empty() {
+            configured_servers.clone()
+        } else {
+            live_snapshot
+        };
+
+        let (mut live_servers, mut selected_reflected) = self
+            .probe_stun_batch_for_family(&primary_servers, family, attempt, bind_ip)
+            .await;
+
+        if selected_reflected.is_none() && !configured_servers.is_empty() && primary_servers != configured_servers {
+            let (rediscovered_live, rediscovered_reflected) = self
+                .probe_stun_batch_for_family(&configured_servers, family, attempt, bind_ip)
+                .await;
+            live_servers = rediscovered_live;
+            selected_reflected = rediscovered_reflected;
+        }
+
+        let live_server_count = live_servers.len();
+        if !live_servers.is_empty() {
+            *self.nat_stun_live_servers.write().await = live_servers;
+        } else {
+            self.nat_stun_live_servers.write().await.clear();
+        }
+
+        if let Some(reflected_addr) = selected_reflected {
+            if use_shared_cache {
+                self.nat_probe_attempts.store(0, std::sync::atomic::Ordering::Relaxed);
+            }
+            info!(
+                family = ?family,
+                live_servers = live_server_count,
+                "STUN-Quorum reached, IP: {}",
+                reflected_addr.ip()
+            );
+            if use_shared_cache
+                && let Ok(mut cache) = self.nat_reflection_cache.try_lock()
+            {
+                let slot = match family {
+                    IpFamily::V4 => &mut cache.v4,
+                    IpFamily::V6 => &mut cache.v6,
+                };
+                *slot = Some((Instant::now(), reflected_addr));
+            }
+            return Some(reflected_addr);
+        }
+
+        if use_shared_cache {
+            let backoff = Duration::from_secs(60 * 2u64.pow((attempt as u32).min(6)));
+            *self.stun_backoff_until.write().await = Some(Instant::now() + backoff);
+        }
         None
     }
 }

src/transport/middle_proxy/pool_refill.rs

@@ -0,0 +1,303 @@
+use std::collections::HashSet;
+use std::net::SocketAddr;
+use std::sync::Arc;
+use std::sync::atomic::Ordering;
+use std::time::{Duration, Instant};
+
+use tracing::{debug, info, warn};
+
+use crate::crypto::SecureRandom;
+use crate::network::IpFamily;
+
+use super::pool::{MePool, RefillDcKey, WriterContour};
+
+const ME_FLAP_UPTIME_THRESHOLD_SECS: u64 = 20;
+const ME_FLAP_QUARANTINE_SECS: u64 = 25;
+
+impl MePool {
+    pub(super) async fn maybe_quarantine_flapping_endpoint(
+        &self,
+        addr: SocketAddr,
+        uptime: Duration,
+    ) {
+        if uptime > Duration::from_secs(ME_FLAP_UPTIME_THRESHOLD_SECS) {
+            return;
+        }
+
+        let until = Instant::now() + Duration::from_secs(ME_FLAP_QUARANTINE_SECS);
+        let mut guard = self.endpoint_quarantine.lock().await;
+        guard.retain(|_, expiry| *expiry > Instant::now());
+        guard.insert(addr, until);
+        self.stats.increment_me_endpoint_quarantine_total();
+        warn!(
+            %addr,
+            uptime_ms = uptime.as_millis(),
+            quarantine_secs = ME_FLAP_QUARANTINE_SECS,
+            "ME endpoint temporarily quarantined due to rapid writer flap"
+        );
+    }
+
+    pub(super) async fn is_endpoint_quarantined(&self, addr: SocketAddr) -> bool {
+        let mut guard = self.endpoint_quarantine.lock().await;
+        let now = Instant::now();
+        guard.retain(|_, expiry| *expiry > now);
+        guard.contains_key(&addr)
+    }
+
+    async fn connectable_endpoints(&self, endpoints: &[SocketAddr]) -> Vec<SocketAddr> {
+        if endpoints.is_empty() {
+            return Vec::new();
+        }
+
+        let mut guard = self.endpoint_quarantine.lock().await;
+        let now = Instant::now();
+        guard.retain(|_, expiry| *expiry > now);
+
+        let mut ready = Vec::<SocketAddr>::with_capacity(endpoints.len());
+        let mut earliest_quarantine: Option<(SocketAddr, Instant)> = None;
+        for addr in endpoints {
+            if let Some(expiry) = guard.get(addr).copied() {
+                match earliest_quarantine {
+                    Some((_, current_expiry)) if current_expiry <= expiry => {}
+                    _ => earliest_quarantine = Some((*addr, expiry)),
+                }
+            } else {
+                ready.push(*addr);
+            }
+        }
+
+        if !ready.is_empty() {
+            return ready;
+        }
+
+        if let Some((addr, expiry)) = earliest_quarantine {
+            debug!(
+                %addr,
+                wait_ms = expiry.saturating_duration_since(now).as_millis(),
+                "All ME endpoints are quarantined for the DC group; retrying earliest one"
+            );
+            return vec![addr];
+        }
+
+        Vec::new()
+    }
+
+    pub(super) async fn has_refill_inflight_for_endpoints(&self, endpoints: &[SocketAddr]) -> bool {
+        if endpoints.is_empty() {
+            return false;
+        }
+
+        {
+            let guard = self.refill_inflight.lock().await;
+            if endpoints.iter().any(|addr| guard.contains(addr)) {
+                return true;
+            }
+        }
+
+        let dc_keys = self.resolve_refill_dc_keys_for_endpoints(endpoints).await;
+        if dc_keys.is_empty() {
+            return false;
+        }
+        let guard = self.refill_inflight_dc.lock().await;
+        dc_keys.iter().any(|key| guard.contains(key))
+    }
+
+    async fn resolve_refill_dc_key_for_addr(&self, addr: SocketAddr) -> Option<RefillDcKey> {
+        let family = if addr.is_ipv4() {
+            IpFamily::V4
+        } else {
+            IpFamily::V6
+        };
+        Some(RefillDcKey {
+            dc: self.resolve_dc_for_endpoint(addr).await,
+            family,
+        })
+    }
+
+    async fn resolve_refill_dc_keys_for_endpoints(
+        &self,
+        endpoints: &[SocketAddr],
+    ) -> HashSet<RefillDcKey> {
+        let mut out = HashSet::<RefillDcKey>::new();
+        for addr in endpoints {
+            if let Some(key) = self.resolve_refill_dc_key_for_addr(*addr).await {
+                out.insert(key);
+            }
+        }
+        out
+    }
+
+    pub(super) async fn connect_endpoints_round_robin(
+        self: &Arc<Self>,
+        endpoints: &[SocketAddr],
+        rng: &SecureRandom,
+    ) -> bool {
+        self.connect_endpoints_round_robin_with_generation_contour(
+            endpoints,
+            rng,
+            self.current_generation(),
+            WriterContour::Active,
+        )
+        .await
+    }
+
+    pub(super) async fn connect_endpoints_round_robin_with_generation_contour(
+        self: &Arc<Self>,
+        endpoints: &[SocketAddr],
+        rng: &SecureRandom,
+        generation: u64,
+        contour: WriterContour,
+    ) -> bool {
+        let candidates = self.connectable_endpoints(endpoints).await;
+        if candidates.is_empty() {
+            return false;
+        }
+        let start = (self.rr.fetch_add(1, Ordering::Relaxed) as usize) % candidates.len();
+        for offset in 0..candidates.len() {
+            let idx = (start + offset) % candidates.len();
+            let addr = candidates[idx];
+            match self
+                .connect_one_with_generation_contour(addr, rng, generation, contour)
+                .await
+            {
+                Ok(()) => return true,
+                Err(e) => debug!(%addr, error = %e, "ME connect failed during round-robin warmup"),
+            }
+        }
+        false
+    }
+
+    async fn endpoints_for_same_dc(&self, addr: SocketAddr) -> Vec<SocketAddr> {
+        let mut endpoints = HashSet::<SocketAddr>::new();
+        let target_dc = self.resolve_dc_for_endpoint(addr).await;
+
+        if self.decision.ipv4_me {
+            let map = self.proxy_map_v4.read().await;
+            if let Some(addrs) = map.get(&target_dc) {
+                for (ip, port) in addrs {
+                    endpoints.insert(SocketAddr::new(*ip, *port));
+                }
+            }
+        }
+
+        if self.decision.ipv6_me {
+            let map = self.proxy_map_v6.read().await;
+            if let Some(addrs) = map.get(&target_dc) {
+                for (ip, port) in addrs {
+                    endpoints.insert(SocketAddr::new(*ip, *port));
+                }
+            }
+        }
+
+        let mut sorted: Vec<SocketAddr> = endpoints.into_iter().collect();
+        sorted.sort_unstable();
+        sorted
+    }
+
+    async fn refill_writer_after_loss(self: &Arc<Self>, addr: SocketAddr) -> bool {
+        let fast_retries = self.me_reconnect_fast_retry_count.max(1);
+        let same_endpoint_quarantined = self.is_endpoint_quarantined(addr).await;
+
+        if !same_endpoint_quarantined {
+            for attempt in 0..fast_retries {
+                self.stats.increment_me_reconnect_attempt();
+                match self.connect_one(addr, self.rng.as_ref()).await {
+                    Ok(()) => {
+                        self.stats.increment_me_reconnect_success();
+                        self.stats.increment_me_writer_restored_same_endpoint_total();
+                        info!(
+                            %addr,
+                            attempt = attempt + 1,
+                            "ME writer restored on the same endpoint"
+                        );
+                        return true;
+                    }
+                    Err(e) => {
+                        debug!(
+                            %addr,
+                            attempt = attempt + 1,
+                            error = %e,
+                            "ME immediate same-endpoint reconnect failed"
+                        );
+                    }
+                }
+            }
+        } else {
+            debug!(
+                %addr,
+                "Skipping immediate same-endpoint reconnect because endpoint is quarantined"
+            );
+        }
+
+        let dc_endpoints = self.endpoints_for_same_dc(addr).await;
+        if dc_endpoints.is_empty() {
+            self.stats.increment_me_refill_failed_total();
+            return false;
+        }
+
+        for attempt in 0..fast_retries {
+            self.stats.increment_me_reconnect_attempt();
+            if self
+                .connect_endpoints_round_robin(&dc_endpoints, self.rng.as_ref())
+                .await
+            {
+                self.stats.increment_me_reconnect_success();
+                self.stats.increment_me_writer_restored_fallback_total();
+                info!(
+                    %addr,
+                    attempt = attempt + 1,
+                    "ME writer restored via DC fallback endpoint"
+                );
+                return true;
+            }
+        }
+
+        self.stats.increment_me_refill_failed_total();
+        false
+    }
+
+    pub(crate) fn trigger_immediate_refill(self: &Arc<Self>, addr: SocketAddr) {
+        let pool = Arc::clone(self);
+        tokio::spawn(async move {
+            let dc_endpoints = pool.endpoints_for_same_dc(addr).await;
+            let dc_keys = pool.resolve_refill_dc_keys_for_endpoints(&dc_endpoints).await;
+
+            {
+                let mut guard = pool.refill_inflight.lock().await;
+                if !guard.insert(addr) {
+                    pool.stats.increment_me_refill_skipped_inflight_total();
+                    return;
+                }
+            }
+
+            if !dc_keys.is_empty() {
+                let mut dc_guard = pool.refill_inflight_dc.lock().await;
+                if dc_keys.iter().any(|key| dc_guard.contains(key)) {
+                    pool.stats.increment_me_refill_skipped_inflight_total();
+                    drop(dc_guard);
+                    let mut guard = pool.refill_inflight.lock().await;
+                    guard.remove(&addr);
+                    return;
+                }
+                dc_guard.extend(dc_keys.iter().copied());
+            }
+
+            pool.stats.increment_me_refill_triggered_total();
+
+            let restored = pool.refill_writer_after_loss(addr).await;
+            if !restored {
+                warn!(%addr, "ME immediate refill failed");
+            }
+
+            let mut guard = pool.refill_inflight.lock().await;
+            guard.remove(&addr);
+            drop(guard);
+            if !dc_keys.is_empty() {
+                let mut dc_guard = pool.refill_inflight_dc.lock().await;
+                for key in &dc_keys {
+                    dc_guard.remove(key);
+                }
+            }
+        });
+    }
+}

src/transport/middle_proxy/pool_reinit.rs

@@ -0,0 +1,493 @@
+use std::collections::{HashMap, HashSet};
+use std::hash::{Hash, Hasher};
+use std::net::SocketAddr;
+use std::sync::Arc;
+use std::sync::atomic::Ordering;
+use std::time::Duration;
+
+use rand::Rng;
+use rand::seq::SliceRandom;
+use tracing::{debug, info, warn};
+use std::collections::hash_map::DefaultHasher;
+
+use crate::crypto::SecureRandom;
+
+use super::pool::{MePool, WriterContour};
+
+const ME_HARDSWAP_PENDING_TTL_SECS: u64 = 1800;
+
+impl MePool {
+    fn desired_map_hash(desired_by_dc: &HashMap<i32, HashSet<SocketAddr>>) -> u64 {
+        let mut hasher = DefaultHasher::new();
+        let mut dcs: Vec<i32> = desired_by_dc.keys().copied().collect();
+        dcs.sort_unstable();
+        for dc in dcs {
+            dc.hash(&mut hasher);
+            let mut endpoints: Vec<SocketAddr> = desired_by_dc
+                .get(&dc)
+                .map(|set| set.iter().copied().collect())
+                .unwrap_or_default();
+            endpoints.sort_unstable();
+            for endpoint in endpoints {
+                endpoint.hash(&mut hasher);
+            }
+        }
+        hasher.finish()
+    }
+
+    fn clear_pending_hardswap_state(&self) {
+        self.pending_hardswap_generation.store(0, Ordering::Relaxed);
+        self.pending_hardswap_started_at_epoch_secs
+            .store(0, Ordering::Relaxed);
+        self.pending_hardswap_map_hash.store(0, Ordering::Relaxed);
+        self.warm_generation.store(0, Ordering::Relaxed);
+    }
+
+    async fn promote_warm_generation_to_active(&self, generation: u64) {
+        self.active_generation.store(generation, Ordering::Relaxed);
+        self.warm_generation.store(0, Ordering::Relaxed);
+
+        let ws = self.writers.read().await;
+        for writer in ws.iter() {
+            if writer.draining.load(Ordering::Relaxed) {
+                continue;
+            }
+            if writer.generation == generation {
+                writer
+                    .contour
+                    .store(WriterContour::Active.as_u8(), Ordering::Relaxed);
+            }
+        }
+    }
+
+    fn coverage_ratio(
+        desired_by_dc: &HashMap<i32, HashSet<SocketAddr>>,
+        active_writer_addrs: &HashSet<SocketAddr>,
+    ) -> (f32, Vec<i32>) {
+        if desired_by_dc.is_empty() {
+            return (1.0, Vec::new());
+        }
+
+        let mut missing_dc = Vec::<i32>::new();
+        let mut covered = 0usize;
+        for (dc, endpoints) in desired_by_dc {
+            if endpoints.is_empty() {
+                continue;
+            }
+            if endpoints
+                .iter()
+                .any(|addr| active_writer_addrs.contains(addr))
+            {
+                covered += 1;
+            } else {
+                missing_dc.push(*dc);
+            }
+        }
+
+        missing_dc.sort_unstable();
+        let total = desired_by_dc.len().max(1);
+        let ratio = (covered as f32) / (total as f32);
+        (ratio, missing_dc)
+    }
+
+    pub async fn reconcile_connections(self: &Arc<Self>, rng: &SecureRandom) {
+        let writers = self.writers.read().await;
+        let current: HashSet<SocketAddr> = writers
+            .iter()
+            .filter(|w| !w.draining.load(Ordering::Relaxed))
+            .map(|w| w.addr)
+            .collect();
+        drop(writers);
+
+        for family in self.family_order() {
+            let map = self.proxy_map_for_family(family).await;
+            for (_dc, addrs) in &map {
+                let dc_addrs: Vec<SocketAddr> = addrs
+                    .iter()
+                    .map(|(ip, port)| SocketAddr::new(*ip, *port))
+                    .collect();
+                if !dc_addrs.iter().any(|a| current.contains(a)) {
+                    let mut shuffled = dc_addrs.clone();
+                    shuffled.shuffle(&mut rand::rng());
+                    for addr in shuffled {
+                        if self.connect_one(addr, rng).await.is_ok() {
+                            break;
+                        }
+                    }
+                }
+            }
+            if !self.decision.effective_multipath && !current.is_empty() {
+                break;
+            }
+        }
+    }
+
+    async fn desired_dc_endpoints(&self) -> HashMap<i32, HashSet<SocketAddr>> {
+        let mut out: HashMap<i32, HashSet<SocketAddr>> = HashMap::new();
+
+        if self.decision.ipv4_me {
+            let map_v4 = self.proxy_map_v4.read().await.clone();
+            for (dc, addrs) in map_v4 {
+                let entry = out.entry(dc).or_default();
+                for (ip, port) in addrs {
+                    entry.insert(SocketAddr::new(ip, port));
+                }
+            }
+        }
+
+        if self.decision.ipv6_me {
+            let map_v6 = self.proxy_map_v6.read().await.clone();
+            for (dc, addrs) in map_v6 {
+                let entry = out.entry(dc).or_default();
+                for (ip, port) in addrs {
+                    entry.insert(SocketAddr::new(ip, port));
+                }
+            }
+        }
+
+        out
+    }
+
+    fn hardswap_warmup_connect_delay_ms(&self) -> u64 {
+        let min_ms = self.me_hardswap_warmup_delay_min_ms.load(Ordering::Relaxed);
+        let max_ms = self.me_hardswap_warmup_delay_max_ms.load(Ordering::Relaxed);
+        let (min_ms, max_ms) = if min_ms <= max_ms {
+            (min_ms, max_ms)
+        } else {
+            (max_ms, min_ms)
+        };
+        if min_ms == max_ms {
+            return min_ms;
+        }
+        rand::rng().random_range(min_ms..=max_ms)
+    }
+
+    fn hardswap_warmup_backoff_ms(&self, pass_idx: usize) -> u64 {
+        let base_ms = self
+            .me_hardswap_warmup_pass_backoff_base_ms
+            .load(Ordering::Relaxed);
+        let cap_ms = (self.me_reconnect_backoff_cap.as_millis() as u64).max(base_ms);
+        let shift = (pass_idx as u32).min(20);
+        let scaled = base_ms.saturating_mul(1u64 << shift);
+        let core = scaled.min(cap_ms);
+        let jitter = (core / 2).max(1);
+        core.saturating_add(rand::rng().random_range(0..=jitter))
+    }
+
+    async fn fresh_writer_count_for_endpoints(
+        &self,
+        generation: u64,
+        endpoints: &HashSet<SocketAddr>,
+    ) -> usize {
+        let ws = self.writers.read().await;
+        ws.iter()
+            .filter(|w| !w.draining.load(Ordering::Relaxed))
+            .filter(|w| w.generation == generation)
+            .filter(|w| endpoints.contains(&w.addr))
+            .count()
+    }
+
+    pub(super) async fn active_writer_count_for_endpoints(
+        &self,
+        endpoints: &HashSet<SocketAddr>,
+    ) -> usize {
+        let ws = self.writers.read().await;
+        ws.iter()
+            .filter(|w| !w.draining.load(Ordering::Relaxed))
+            .filter(|w| endpoints.contains(&w.addr))
+            .count()
+    }
+
+    async fn warmup_generation_for_all_dcs(
+        self: &Arc<Self>,
+        rng: &SecureRandom,
+        generation: u64,
+        desired_by_dc: &HashMap<i32, HashSet<SocketAddr>>,
+    ) {
+        let extra_passes = self
+            .me_hardswap_warmup_extra_passes
+            .load(Ordering::Relaxed)
+            .min(10) as usize;
+        let total_passes = 1 + extra_passes;
+
+        for (dc, endpoints) in desired_by_dc {
+            if endpoints.is_empty() {
+                continue;
+            }
+
+            let mut endpoint_list: Vec<SocketAddr> = endpoints.iter().copied().collect();
+            endpoint_list.sort_unstable();
+            let required = self.required_writers_for_dc(endpoint_list.len());
+            let mut completed = false;
+            let mut last_fresh_count = self
+                .fresh_writer_count_for_endpoints(generation, endpoints)
+                .await;
+
+            for pass_idx in 0..total_passes {
+                if last_fresh_count >= required {
+                    completed = true;
+                    break;
+                }
+
+                let missing = required.saturating_sub(last_fresh_count);
+                debug!(
+                    dc = *dc,
+                    pass = pass_idx + 1,
+                    total_passes,
+                    fresh_count = last_fresh_count,
+                    required,
+                    missing,
+                    endpoint_count = endpoint_list.len(),
+                    "ME hardswap warmup pass started"
+                );
+
+                for attempt_idx in 0..missing {
+                    let delay_ms = self.hardswap_warmup_connect_delay_ms();
+                    tokio::time::sleep(Duration::from_millis(delay_ms)).await;
+
+                    let connected = self
+                        .connect_endpoints_round_robin_with_generation_contour(
+                            &endpoint_list,
+                            rng,
+                            generation,
+                            WriterContour::Warm,
+                        )
+                        .await;
+                    debug!(
+                        dc = *dc,
+                        pass = pass_idx + 1,
+                        total_passes,
+                        attempt = attempt_idx + 1,
+                        delay_ms,
+                        connected,
+                        "ME hardswap warmup connect attempt finished"
+                    );
+                }
+
+                last_fresh_count = self
+                    .fresh_writer_count_for_endpoints(generation, endpoints)
+                    .await;
+                if last_fresh_count >= required {
+                    completed = true;
+                    info!(
+                        dc = *dc,
+                        pass = pass_idx + 1,
+                        total_passes,
+                        fresh_count = last_fresh_count,
+                        required,
+                        "ME hardswap warmup floor reached for DC"
+                    );
+                    break;
+                }
+
+                if pass_idx + 1 < total_passes {
+                    let backoff_ms = self.hardswap_warmup_backoff_ms(pass_idx);
+                    debug!(
+                        dc = *dc,
+                        pass = pass_idx + 1,
+                        total_passes,
+                        fresh_count = last_fresh_count,
+                        required,
+                        backoff_ms,
+                        "ME hardswap warmup pass incomplete, delaying next pass"
+                    );
+                    tokio::time::sleep(Duration::from_millis(backoff_ms)).await;
+                }
+            }
+
+            if !completed {
+                warn!(
+                    dc = *dc,
+                    fresh_count = last_fresh_count,
+                    required,
+                    endpoint_count = endpoint_list.len(),
+                    total_passes,
+                    "ME warmup stopped: unable to reach required writer floor for DC"
+                );
+            }
+        }
+    }
+
+    pub async fn zero_downtime_reinit_after_map_change(self: &Arc<Self>, rng: &SecureRandom) {
+        let desired_by_dc = self.desired_dc_endpoints().await;
+        if desired_by_dc.is_empty() {
+            warn!("ME endpoint map is empty; skipping stale writer drain");
+            return;
+        }
+
+        let desired_map_hash = Self::desired_map_hash(&desired_by_dc);
+        let now_epoch_secs = Self::now_epoch_secs();
+        let previous_generation = self.current_generation();
+        let hardswap = self.hardswap.load(Ordering::Relaxed);
+        let generation = if hardswap {
+            let pending_generation = self.pending_hardswap_generation.load(Ordering::Relaxed);
+            let pending_started_at = self
+                .pending_hardswap_started_at_epoch_secs
+                .load(Ordering::Relaxed);
+            let pending_map_hash = self.pending_hardswap_map_hash.load(Ordering::Relaxed);
+            let pending_age_secs = now_epoch_secs.saturating_sub(pending_started_at);
+            let pending_ttl_expired = pending_started_at > 0 && pending_age_secs > ME_HARDSWAP_PENDING_TTL_SECS;
+            let pending_matches_map = pending_map_hash != 0 && pending_map_hash == desired_map_hash;
+
+            if pending_generation != 0
+                && pending_generation >= previous_generation
+                && pending_matches_map
+                && !pending_ttl_expired
+            {
+                self.stats.increment_me_hardswap_pending_reuse_total();
+                debug!(
+                    previous_generation,
+                    generation = pending_generation,
+                    pending_age_secs,
+                    "ME hardswap continues with pending generation"
+                );
+                pending_generation
+            } else {
+                if pending_generation != 0 && pending_ttl_expired {
+                    self.stats.increment_me_hardswap_pending_ttl_expired_total();
+                    warn!(
+                        previous_generation,
+                        generation = pending_generation,
+                        pending_age_secs,
+                        pending_ttl_secs = ME_HARDSWAP_PENDING_TTL_SECS,
+                        "ME hardswap pending generation expired by TTL; starting fresh generation"
+                    );
+                }
+                let next_generation = self.generation.fetch_add(1, Ordering::Relaxed) + 1;
+                self.pending_hardswap_generation
+                    .store(next_generation, Ordering::Relaxed);
+                self.pending_hardswap_started_at_epoch_secs
+                    .store(now_epoch_secs, Ordering::Relaxed);
+                self.pending_hardswap_map_hash
+                    .store(desired_map_hash, Ordering::Relaxed);
+                self.warm_generation.store(next_generation, Ordering::Relaxed);
+                next_generation
+            }
+        } else {
+            self.clear_pending_hardswap_state();
+            self.generation.fetch_add(1, Ordering::Relaxed) + 1
+        };
+
+        if hardswap {
+            self.warm_generation.store(generation, Ordering::Relaxed);
+            self.warmup_generation_for_all_dcs(rng, generation, &desired_by_dc)
+                .await;
+        } else {
+            self.reconcile_connections(rng).await;
+        }
+
+        let writers = self.writers.read().await;
+        let active_writer_addrs: HashSet<SocketAddr> = writers
+            .iter()
+            .filter(|w| !w.draining.load(Ordering::Relaxed))
+            .map(|w| w.addr)
+            .collect();
+        let min_ratio = Self::permille_to_ratio(
+            self.me_pool_min_fresh_ratio_permille
+                .load(Ordering::Relaxed),
+        );
+        let (coverage_ratio, missing_dc) = Self::coverage_ratio(&desired_by_dc, &active_writer_addrs);
+        if !hardswap && coverage_ratio < min_ratio {
+            warn!(
+                previous_generation,
+                generation,
+                coverage_ratio = format_args!("{coverage_ratio:.3}"),
+                min_ratio = format_args!("{min_ratio:.3}"),
+                missing_dc = ?missing_dc,
+                "ME reinit coverage below threshold; keeping stale writers"
+            );
+            return;
+        }
+
+        if hardswap {
+            let mut fresh_missing_dc = Vec::<(i32, usize, usize)>::new();
+            for (dc, endpoints) in &desired_by_dc {
+                if endpoints.is_empty() {
+                    continue;
+                }
+                let required = self.required_writers_for_dc(endpoints.len());
+                let fresh_count = writers
+                    .iter()
+                    .filter(|w| !w.draining.load(Ordering::Relaxed))
+                    .filter(|w| w.generation == generation)
+                    .filter(|w| endpoints.contains(&w.addr))
+                    .count();
+                if fresh_count < required {
+                    fresh_missing_dc.push((*dc, fresh_count, required));
+                }
+            }
+            if !fresh_missing_dc.is_empty() {
+                warn!(
+                    previous_generation,
+                    generation,
+                    missing_dc = ?fresh_missing_dc,
+                    "ME hardswap pending: fresh generation coverage incomplete"
+                );
+                return;
+            }
+        } else if !missing_dc.is_empty() {
+            warn!(
+                missing_dc = ?missing_dc,
+                // Keep stale writers alive when fresh coverage is incomplete.
+                "ME reinit coverage incomplete; keeping stale writers"
+            );
+            return;
+        }
+
+        if hardswap {
+            self.promote_warm_generation_to_active(generation).await;
+        }
+
+        let desired_addrs: HashSet<SocketAddr> = desired_by_dc
+            .values()
+            .flat_map(|set| set.iter().copied())
+            .collect();
+
+        let stale_writer_ids: Vec<u64> = writers
+            .iter()
+            .filter(|w| !w.draining.load(Ordering::Relaxed))
+            .filter(|w| {
+                if hardswap {
+                    w.generation < generation
+                } else {
+                    !desired_addrs.contains(&w.addr)
+                }
+            })
+            .map(|w| w.id)
+            .collect();
+        drop(writers);
+
+        if stale_writer_ids.is_empty() {
+            if hardswap {
+                self.clear_pending_hardswap_state();
+            }
+            debug!("ME reinit cycle completed with no stale writers");
+            return;
+        }
+
+        let drain_timeout = self.force_close_timeout();
+        let drain_timeout_secs = drain_timeout.map(|d| d.as_secs()).unwrap_or(0);
+        info!(
+            stale_writers = stale_writer_ids.len(),
+            previous_generation,
+            generation,
+            hardswap,
+            coverage_ratio = format_args!("{coverage_ratio:.3}"),
+            min_ratio = format_args!("{min_ratio:.3}"),
+            drain_timeout_secs,
+            "ME reinit cycle covered; draining stale writers"
+        );
+        self.stats.increment_pool_swap_total();
+        for writer_id in stale_writer_ids {
+            self.mark_writer_draining_with_timeout(writer_id, drain_timeout, !hardswap)
+                .await;
+        }
+        if hardswap {
+            self.clear_pending_hardswap_state();
+        }
+    }
+
+    pub async fn zero_downtime_reinit_periodic(self: &Arc<Self>, rng: &SecureRandom) {
+        self.zero_downtime_reinit_after_map_change(rng).await;
+    }
+}

src/transport/middle_proxy/pool_runtime_api.rs

@@ -0,0 +1,128 @@
+use std::collections::HashMap;
+use std::time::Instant;
+
+use super::pool::{MePool, RefillDcKey};
+use crate::network::IpFamily;
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiRefillDcSnapshot {
+    pub dc: i16,
+    pub family: &'static str,
+    pub inflight: usize,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiRefillSnapshot {
+    pub inflight_endpoints_total: usize,
+    pub inflight_dc_total: usize,
+    pub by_dc: Vec<MeApiRefillDcSnapshot>,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiNatReflectionSnapshot {
+    pub addr: std::net::SocketAddr,
+    pub age_secs: u64,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiNatStunSnapshot {
+    pub nat_probe_enabled: bool,
+    pub nat_probe_disabled_runtime: bool,
+    pub nat_probe_attempts: u8,
+    pub configured_servers: Vec<String>,
+    pub live_servers: Vec<String>,
+    pub reflection_v4: Option<MeApiNatReflectionSnapshot>,
+    pub reflection_v6: Option<MeApiNatReflectionSnapshot>,
+    pub stun_backoff_remaining_ms: Option<u64>,
+}
+
+impl MePool {
+    pub(crate) async fn api_refill_snapshot(&self) -> MeApiRefillSnapshot {
+        let inflight_endpoints_total = self.refill_inflight.lock().await.len();
+        let inflight_dc_keys = self
+            .refill_inflight_dc
+            .lock()
+            .await
+            .iter()
+            .copied()
+            .collect::<Vec<RefillDcKey>>();
+
+        let mut by_dc_map = HashMap::<(i16, &'static str), usize>::new();
+        for key in inflight_dc_keys {
+            let family = match key.family {
+                IpFamily::V4 => "v4",
+                IpFamily::V6 => "v6",
+            };
+            let dc = key.dc as i16;
+            *by_dc_map.entry((dc, family)).or_insert(0) += 1;
+        }
+
+        let mut by_dc = by_dc_map
+            .into_iter()
+            .map(|((dc, family), inflight)| MeApiRefillDcSnapshot {
+                dc,
+                family,
+                inflight,
+            })
+            .collect::<Vec<_>>();
+        by_dc.sort_by_key(|entry| (entry.dc, entry.family));
+
+        MeApiRefillSnapshot {
+            inflight_endpoints_total,
+            inflight_dc_total: by_dc.len(),
+            by_dc,
+        }
+    }
+
+    pub(crate) async fn api_nat_stun_snapshot(&self) -> MeApiNatStunSnapshot {
+        let now = Instant::now();
+        let mut configured_servers = if !self.nat_stun_servers.is_empty() {
+            self.nat_stun_servers.clone()
+        } else if let Some(stun) = &self.nat_stun {
+            if stun.trim().is_empty() {
+                Vec::new()
+            } else {
+                vec![stun.clone()]
+            }
+        } else {
+            Vec::new()
+        };
+        configured_servers.sort();
+        configured_servers.dedup();
+
+        let mut live_servers = self.nat_stun_live_servers.read().await.clone();
+        live_servers.sort();
+        live_servers.dedup();
+
+        let reflection = self.nat_reflection_cache.lock().await;
+        let reflection_v4 = reflection.v4.map(|(ts, addr)| MeApiNatReflectionSnapshot {
+            addr,
+            age_secs: now.saturating_duration_since(ts).as_secs(),
+        });
+        let reflection_v6 = reflection.v6.map(|(ts, addr)| MeApiNatReflectionSnapshot {
+            addr,
+            age_secs: now.saturating_duration_since(ts).as_secs(),
+        });
+        drop(reflection);
+
+        let backoff_until = *self.stun_backoff_until.read().await;
+        let stun_backoff_remaining_ms = backoff_until.and_then(|until| {
+            (until > now).then_some(until.duration_since(now).as_millis() as u64)
+        });
+
+        MeApiNatStunSnapshot {
+            nat_probe_enabled: self.nat_probe,
+            nat_probe_disabled_runtime: self
+                .nat_probe_disabled
+                .load(std::sync::atomic::Ordering::Relaxed),
+            nat_probe_attempts: self
+                .nat_probe_attempts
+                .load(std::sync::atomic::Ordering::Relaxed),
+            configured_servers,
+            live_servers,
+            reflection_v4,
+            reflection_v6,
+            stun_backoff_remaining_ms,
+        }
+    }
+}

src/transport/middle_proxy/pool_status.rs

@@ -0,0 +1,581 @@
+use std::collections::{BTreeMap, BTreeSet, HashMap};
+use std::net::{IpAddr, SocketAddr};
+use std::sync::atomic::Ordering;
+use std::time::Instant;
+
+use super::pool::{MePool, WriterContour};
+use crate::config::{MeBindStaleMode, MeFloorMode, MeSocksKdfPolicy};
+use crate::transport::upstream::IpPreference;
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiWriterStatusSnapshot {
+    pub writer_id: u64,
+    pub dc: Option<i16>,
+    pub endpoint: SocketAddr,
+    pub generation: u64,
+    pub state: &'static str,
+    pub draining: bool,
+    pub degraded: bool,
+    pub bound_clients: usize,
+    pub idle_for_secs: Option<u64>,
+    pub rtt_ema_ms: Option<f64>,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiDcStatusSnapshot {
+    pub dc: i16,
+    pub endpoints: Vec<SocketAddr>,
+    pub available_endpoints: usize,
+    pub available_pct: f64,
+    pub required_writers: usize,
+    pub floor_min: usize,
+    pub floor_target: usize,
+    pub floor_max: usize,
+    pub floor_capped: bool,
+    pub alive_writers: usize,
+    pub coverage_pct: f64,
+    pub rtt_ms: Option<f64>,
+    pub load: usize,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiStatusSnapshot {
+    pub generated_at_epoch_secs: u64,
+    pub configured_dc_groups: usize,
+    pub configured_endpoints: usize,
+    pub available_endpoints: usize,
+    pub available_pct: f64,
+    pub required_writers: usize,
+    pub alive_writers: usize,
+    pub coverage_pct: f64,
+    pub writers: Vec<MeApiWriterStatusSnapshot>,
+    pub dcs: Vec<MeApiDcStatusSnapshot>,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiQuarantinedEndpointSnapshot {
+    pub endpoint: SocketAddr,
+    pub remaining_ms: u64,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiDcPathSnapshot {
+    pub dc: i16,
+    pub ip_preference: Option<&'static str>,
+    pub selected_addr_v4: Option<SocketAddr>,
+    pub selected_addr_v6: Option<SocketAddr>,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct MeApiRuntimeSnapshot {
+    pub active_generation: u64,
+    pub warm_generation: u64,
+    pub pending_hardswap_generation: u64,
+    pub pending_hardswap_age_secs: Option<u64>,
+    pub hardswap_enabled: bool,
+    pub floor_mode: &'static str,
+    pub adaptive_floor_idle_secs: u64,
+    pub adaptive_floor_min_writers_single_endpoint: u8,
+    pub adaptive_floor_min_writers_multi_endpoint: u8,
+    pub adaptive_floor_recover_grace_secs: u64,
+    pub adaptive_floor_writers_per_core_total: u16,
+    pub adaptive_floor_cpu_cores_override: u16,
+    pub adaptive_floor_max_extra_writers_single_per_core: u16,
+    pub adaptive_floor_max_extra_writers_multi_per_core: u16,
+    pub adaptive_floor_cpu_cores_detected: u32,
+    pub adaptive_floor_cpu_cores_effective: u32,
+    pub adaptive_floor_global_cap_raw: u64,
+    pub adaptive_floor_global_cap_effective: u64,
+    pub adaptive_floor_target_writers_total: u64,
+    pub me_keepalive_enabled: bool,
+    pub me_keepalive_interval_secs: u64,
+    pub me_keepalive_jitter_secs: u64,
+    pub me_keepalive_payload_random: bool,
+    pub rpc_proxy_req_every_secs: u64,
+    pub me_reconnect_max_concurrent_per_dc: u32,
+    pub me_reconnect_backoff_base_ms: u64,
+    pub me_reconnect_backoff_cap_ms: u64,
+    pub me_reconnect_fast_retry_count: u32,
+    pub me_pool_drain_ttl_secs: u64,
+    pub me_pool_force_close_secs: u64,
+    pub me_pool_min_fresh_ratio: f32,
+    pub me_bind_stale_mode: &'static str,
+    pub me_bind_stale_ttl_secs: u64,
+    pub me_single_endpoint_shadow_writers: u8,
+    pub me_single_endpoint_outage_mode_enabled: bool,
+    pub me_single_endpoint_outage_disable_quarantine: bool,
+    pub me_single_endpoint_outage_backoff_min_ms: u64,
+    pub me_single_endpoint_outage_backoff_max_ms: u64,
+    pub me_single_endpoint_shadow_rotate_every_secs: u64,
+    pub me_deterministic_writer_sort: bool,
+    pub me_socks_kdf_policy: &'static str,
+    pub quarantined_endpoints: Vec<MeApiQuarantinedEndpointSnapshot>,
+    pub network_path: Vec<MeApiDcPathSnapshot>,
+}
+
+impl MePool {
+    pub(crate) async fn admission_ready_conditional_cast(&self) -> bool {
+        let mut endpoints_by_dc = BTreeMap::<i16, BTreeSet<SocketAddr>>::new();
+        if self.decision.ipv4_me {
+            let map = self.proxy_map_v4.read().await.clone();
+            extend_signed_endpoints(&mut endpoints_by_dc, map);
+        }
+        if self.decision.ipv6_me {
+            let map = self.proxy_map_v6.read().await.clone();
+            extend_signed_endpoints(&mut endpoints_by_dc, map);
+        }
+
+        if endpoints_by_dc.is_empty() {
+            return false;
+        }
+
+        let writers = self.writers.read().await.clone();
+        let mut live_writers_by_endpoint = HashMap::<SocketAddr, usize>::new();
+        for writer in writers {
+            if writer.draining.load(Ordering::Relaxed) {
+                continue;
+            }
+            *live_writers_by_endpoint.entry(writer.addr).or_insert(0) += 1;
+        }
+
+        for endpoints in endpoints_by_dc.values() {
+            let alive: usize = endpoints
+                .iter()
+                .map(|endpoint| live_writers_by_endpoint.get(endpoint).copied().unwrap_or(0))
+                .sum();
+            if alive == 0 {
+                return false;
+            }
+        }
+
+        true
+    }
+
+    #[allow(dead_code)]
+    pub(crate) async fn admission_ready_full_floor(&self) -> bool {
+        let mut endpoints_by_dc = BTreeMap::<i16, BTreeSet<SocketAddr>>::new();
+        if self.decision.ipv4_me {
+            let map = self.proxy_map_v4.read().await.clone();
+            extend_signed_endpoints(&mut endpoints_by_dc, map);
+        }
+        if self.decision.ipv6_me {
+            let map = self.proxy_map_v6.read().await.clone();
+            extend_signed_endpoints(&mut endpoints_by_dc, map);
+        }
+
+        if endpoints_by_dc.is_empty() {
+            return false;
+        }
+
+        let writers = self.writers.read().await.clone();
+        let mut live_writers_by_endpoint = HashMap::<SocketAddr, usize>::new();
+        for writer in writers {
+            if writer.draining.load(Ordering::Relaxed) {
+                continue;
+            }
+            *live_writers_by_endpoint.entry(writer.addr).or_insert(0) += 1;
+        }
+
+        for endpoints in endpoints_by_dc.values() {
+            let endpoint_count = endpoints.len();
+            if endpoint_count == 0 {
+                return false;
+            }
+            let required = self.required_writers_for_dc_with_floor_mode(endpoint_count, false);
+            let alive: usize = endpoints
+                .iter()
+                .map(|endpoint| live_writers_by_endpoint.get(endpoint).copied().unwrap_or(0))
+                .sum();
+            if alive < required {
+                return false;
+            }
+        }
+
+        true
+    }
+
+    pub(crate) async fn api_status_snapshot(&self) -> MeApiStatusSnapshot {
+        let now_epoch_secs = Self::now_epoch_secs();
+
+        let mut endpoints_by_dc = BTreeMap::<i16, BTreeSet<SocketAddr>>::new();
+        if self.decision.ipv4_me {
+            let map = self.proxy_map_v4.read().await.clone();
+            extend_signed_endpoints(&mut endpoints_by_dc, map);
+        }
+        if self.decision.ipv6_me {
+            let map = self.proxy_map_v6.read().await.clone();
+            extend_signed_endpoints(&mut endpoints_by_dc, map);
+        }
+
+        let mut endpoint_to_dc = HashMap::<SocketAddr, BTreeSet<i16>>::new();
+        for (dc, endpoints) in &endpoints_by_dc {
+            for endpoint in endpoints {
+                endpoint_to_dc.entry(*endpoint).or_default().insert(*dc);
+            }
+        }
+
+        let configured_dc_groups = endpoints_by_dc.len();
+        let configured_endpoints = endpoints_by_dc.values().map(BTreeSet::len).sum();
+
+        let required_writers = endpoints_by_dc
+            .values()
+            .map(|endpoints| self.required_writers_for_dc_with_floor_mode(endpoints.len(), false))
+            .sum();
+
+        let idle_since = self.registry.writer_idle_since_snapshot().await;
+        let activity = self.registry.writer_activity_snapshot().await;
+        let rtt = self.rtt_stats.lock().await.clone();
+        let writers = self.writers.read().await.clone();
+
+        let mut live_writers_by_endpoint = HashMap::<SocketAddr, usize>::new();
+        let mut live_writers_by_dc = HashMap::<i16, usize>::new();
+        let mut dc_rtt_agg = HashMap::<i16, (f64, u64)>::new();
+        let mut writer_rows = Vec::<MeApiWriterStatusSnapshot>::with_capacity(writers.len());
+
+        for writer in writers {
+            let endpoint = writer.addr;
+            let dc = endpoint_to_dc.get(&endpoint).and_then(|dcs| {
+                if dcs.len() == 1 {
+                    dcs.iter().next().copied()
+                } else {
+                    None
+                }
+            });
+            let draining = writer.draining.load(Ordering::Relaxed);
+            let degraded = writer.degraded.load(Ordering::Relaxed);
+            let bound_clients = activity
+                .bound_clients_by_writer
+                .get(&writer.id)
+                .copied()
+                .unwrap_or(0);
+            let idle_for_secs = idle_since
+                .get(&writer.id)
+                .map(|idle_ts| now_epoch_secs.saturating_sub(*idle_ts));
+            let rtt_ema_ms = rtt.get(&writer.id).map(|(_, ema)| *ema);
+            let state = match WriterContour::from_u8(writer.contour.load(Ordering::Relaxed)) {
+                WriterContour::Warm => "warm",
+                WriterContour::Active => "active",
+                WriterContour::Draining => "draining",
+            };
+
+            if !draining {
+                *live_writers_by_endpoint.entry(endpoint).or_insert(0) += 1;
+                if let Some(dc_idx) = dc {
+                    *live_writers_by_dc.entry(dc_idx).or_insert(0) += 1;
+                    if let Some(ema_ms) = rtt_ema_ms {
+                        let entry = dc_rtt_agg.entry(dc_idx).or_insert((0.0, 0));
+                        entry.0 += ema_ms;
+                        entry.1 += 1;
+                    }
+                }
+            }
+
+            writer_rows.push(MeApiWriterStatusSnapshot {
+                writer_id: writer.id,
+                dc,
+                endpoint,
+                generation: writer.generation,
+                state,
+                draining,
+                degraded,
+                bound_clients,
+                idle_for_secs,
+                rtt_ema_ms,
+            });
+        }
+
+        writer_rows.sort_by_key(|row| (row.dc.unwrap_or(i16::MAX), row.endpoint, row.writer_id));
+
+        let mut dcs = Vec::<MeApiDcStatusSnapshot>::with_capacity(endpoints_by_dc.len());
+        let mut available_endpoints = 0usize;
+        let mut alive_writers = 0usize;
+        let floor_mode = self.floor_mode();
+        let adaptive_cpu_cores = (self
+            .me_adaptive_floor_cpu_cores_effective
+            .load(Ordering::Relaxed) as usize)
+            .max(1);
+        for (dc, endpoints) in endpoints_by_dc {
+            let endpoint_count = endpoints.len();
+            let dc_available_endpoints = endpoints
+                .iter()
+                .filter(|endpoint| live_writers_by_endpoint.contains_key(endpoint))
+                .count();
+            let base_required = self.required_writers_for_dc(endpoint_count);
+            let dc_required_writers =
+                self.required_writers_for_dc_with_floor_mode(endpoint_count, false);
+            let floor_min = if endpoint_count <= 1 {
+                (self
+                    .me_adaptive_floor_min_writers_single_endpoint
+                    .load(Ordering::Relaxed) as usize)
+                    .max(1)
+                    .min(base_required.max(1))
+            } else {
+                (self
+                    .me_adaptive_floor_min_writers_multi_endpoint
+                    .load(Ordering::Relaxed) as usize)
+                    .max(1)
+                    .min(base_required.max(1))
+            };
+            let extra_per_core = if endpoint_count <= 1 {
+                self.me_adaptive_floor_max_extra_writers_single_per_core
+                    .load(Ordering::Relaxed) as usize
+            } else {
+                self.me_adaptive_floor_max_extra_writers_multi_per_core
+                    .load(Ordering::Relaxed) as usize
+            };
+            let floor_max = base_required.saturating_add(adaptive_cpu_cores.saturating_mul(extra_per_core));
+            let floor_capped = matches!(floor_mode, MeFloorMode::Adaptive)
+                && dc_required_writers < base_required;
+            let dc_alive_writers = live_writers_by_dc.get(&dc).copied().unwrap_or(0);
+            let dc_load = activity
+                .active_sessions_by_target_dc
+                .get(&dc)
+                .copied()
+                .unwrap_or(0);
+            let dc_rtt_ms = dc_rtt_agg
+                .get(&dc)
+                .and_then(|(sum, count)| (*count > 0).then_some(*sum / (*count as f64)));
+
+            available_endpoints += dc_available_endpoints;
+            alive_writers += dc_alive_writers;
+
+            dcs.push(MeApiDcStatusSnapshot {
+                dc,
+                endpoints: endpoints.into_iter().collect(),
+                available_endpoints: dc_available_endpoints,
+                available_pct: ratio_pct(dc_available_endpoints, endpoint_count),
+                required_writers: dc_required_writers,
+                floor_min,
+                floor_target: dc_required_writers,
+                floor_max,
+                floor_capped,
+                alive_writers: dc_alive_writers,
+                coverage_pct: ratio_pct(dc_alive_writers, dc_required_writers),
+                rtt_ms: dc_rtt_ms,
+                load: dc_load,
+            });
+        }
+
+        MeApiStatusSnapshot {
+            generated_at_epoch_secs: now_epoch_secs,
+            configured_dc_groups,
+            configured_endpoints,
+            available_endpoints,
+            available_pct: ratio_pct(available_endpoints, configured_endpoints),
+            required_writers,
+            alive_writers,
+            coverage_pct: ratio_pct(alive_writers, required_writers),
+            writers: writer_rows,
+            dcs,
+        }
+    }
+
+    pub(crate) async fn api_runtime_snapshot(&self) -> MeApiRuntimeSnapshot {
+        let now = Instant::now();
+        let now_epoch_secs = Self::now_epoch_secs();
+        let pending_started_at = self
+            .pending_hardswap_started_at_epoch_secs
+            .load(Ordering::Relaxed);
+        let pending_hardswap_age_secs = (pending_started_at > 0)
+            .then_some(now_epoch_secs.saturating_sub(pending_started_at));
+
+        let mut quarantined_endpoints = Vec::<MeApiQuarantinedEndpointSnapshot>::new();
+        {
+            let guard = self.endpoint_quarantine.lock().await;
+            for (endpoint, expires_at) in guard.iter() {
+                if *expires_at <= now {
+                    continue;
+                }
+                let remaining_ms = expires_at.duration_since(now).as_millis() as u64;
+                quarantined_endpoints.push(MeApiQuarantinedEndpointSnapshot {
+                    endpoint: *endpoint,
+                    remaining_ms,
+                });
+            }
+        }
+        quarantined_endpoints.sort_by_key(|entry| entry.endpoint);
+
+        let mut network_path = Vec::<MeApiDcPathSnapshot>::new();
+        if let Some(upstream) = &self.upstream {
+            for dc in 1..=5 {
+                let dc_idx = dc as i16;
+                let ip_preference = upstream
+                    .get_dc_ip_preference(dc_idx)
+                    .await
+                    .map(ip_preference_label);
+                let selected_addr_v4 = upstream.get_dc_addr(dc_idx, false).await;
+                let selected_addr_v6 = upstream.get_dc_addr(dc_idx, true).await;
+                network_path.push(MeApiDcPathSnapshot {
+                    dc: dc_idx,
+                    ip_preference,
+                    selected_addr_v4,
+                    selected_addr_v6,
+                });
+            }
+        }
+
+        MeApiRuntimeSnapshot {
+            active_generation: self.active_generation.load(Ordering::Relaxed),
+            warm_generation: self.warm_generation.load(Ordering::Relaxed),
+            pending_hardswap_generation: self.pending_hardswap_generation.load(Ordering::Relaxed),
+            pending_hardswap_age_secs,
+            hardswap_enabled: self.hardswap.load(Ordering::Relaxed),
+            floor_mode: floor_mode_label(self.floor_mode()),
+            adaptive_floor_idle_secs: self.me_adaptive_floor_idle_secs.load(Ordering::Relaxed),
+            adaptive_floor_min_writers_single_endpoint: self
+                .me_adaptive_floor_min_writers_single_endpoint
+                .load(Ordering::Relaxed),
+            adaptive_floor_min_writers_multi_endpoint: self
+                .me_adaptive_floor_min_writers_multi_endpoint
+                .load(Ordering::Relaxed),
+            adaptive_floor_recover_grace_secs: self
+                .me_adaptive_floor_recover_grace_secs
+                .load(Ordering::Relaxed),
+            adaptive_floor_writers_per_core_total: self
+                .me_adaptive_floor_writers_per_core_total
+                .load(Ordering::Relaxed) as u16,
+            adaptive_floor_cpu_cores_override: self
+                .me_adaptive_floor_cpu_cores_override
+                .load(Ordering::Relaxed) as u16,
+            adaptive_floor_max_extra_writers_single_per_core: self
+                .me_adaptive_floor_max_extra_writers_single_per_core
+                .load(Ordering::Relaxed) as u16,
+            adaptive_floor_max_extra_writers_multi_per_core: self
+                .me_adaptive_floor_max_extra_writers_multi_per_core
+                .load(Ordering::Relaxed) as u16,
+            adaptive_floor_cpu_cores_detected: self
+                .me_adaptive_floor_cpu_cores_detected
+                .load(Ordering::Relaxed),
+            adaptive_floor_cpu_cores_effective: self
+                .me_adaptive_floor_cpu_cores_effective
+                .load(Ordering::Relaxed),
+            adaptive_floor_global_cap_raw: self
+                .me_adaptive_floor_global_cap_raw
+                .load(Ordering::Relaxed),
+            adaptive_floor_global_cap_effective: self
+                .me_adaptive_floor_global_cap_effective
+                .load(Ordering::Relaxed),
+            adaptive_floor_target_writers_total: self
+                .me_adaptive_floor_target_writers_total
+                .load(Ordering::Relaxed),
+            me_keepalive_enabled: self.me_keepalive_enabled,
+            me_keepalive_interval_secs: self.me_keepalive_interval.as_secs(),
+            me_keepalive_jitter_secs: self.me_keepalive_jitter.as_secs(),
+            me_keepalive_payload_random: self.me_keepalive_payload_random,
+            rpc_proxy_req_every_secs: self.rpc_proxy_req_every_secs.load(Ordering::Relaxed),
+            me_reconnect_max_concurrent_per_dc: self.me_reconnect_max_concurrent_per_dc,
+            me_reconnect_backoff_base_ms: self.me_reconnect_backoff_base.as_millis() as u64,
+            me_reconnect_backoff_cap_ms: self.me_reconnect_backoff_cap.as_millis() as u64,
+            me_reconnect_fast_retry_count: self.me_reconnect_fast_retry_count,
+            me_pool_drain_ttl_secs: self.me_pool_drain_ttl_secs.load(Ordering::Relaxed),
+            me_pool_force_close_secs: self.me_pool_force_close_secs.load(Ordering::Relaxed),
+            me_pool_min_fresh_ratio: Self::permille_to_ratio(
+                self.me_pool_min_fresh_ratio_permille.load(Ordering::Relaxed),
+            ),
+            me_bind_stale_mode: bind_stale_mode_label(self.bind_stale_mode()),
+            me_bind_stale_ttl_secs: self.me_bind_stale_ttl_secs.load(Ordering::Relaxed),
+            me_single_endpoint_shadow_writers: self
+                .me_single_endpoint_shadow_writers
+                .load(Ordering::Relaxed),
+            me_single_endpoint_outage_mode_enabled: self
+                .me_single_endpoint_outage_mode_enabled
+                .load(Ordering::Relaxed),
+            me_single_endpoint_outage_disable_quarantine: self
+                .me_single_endpoint_outage_disable_quarantine
+                .load(Ordering::Relaxed),
+            me_single_endpoint_outage_backoff_min_ms: self
+                .me_single_endpoint_outage_backoff_min_ms
+                .load(Ordering::Relaxed),
+            me_single_endpoint_outage_backoff_max_ms: self
+                .me_single_endpoint_outage_backoff_max_ms
+                .load(Ordering::Relaxed),
+            me_single_endpoint_shadow_rotate_every_secs: self
+                .me_single_endpoint_shadow_rotate_every_secs
+                .load(Ordering::Relaxed),
+            me_deterministic_writer_sort: self
+                .me_deterministic_writer_sort
+                .load(Ordering::Relaxed),
+            me_socks_kdf_policy: socks_kdf_policy_label(self.socks_kdf_policy()),
+            quarantined_endpoints,
+            network_path,
+        }
+    }
+}
+
+fn ratio_pct(part: usize, total: usize) -> f64 {
+    if total == 0 {
+        return 0.0;
+    }
+    let pct = ((part as f64) / (total as f64)) * 100.0;
+    pct.clamp(0.0, 100.0)
+}
+
+fn extend_signed_endpoints(
+    endpoints_by_dc: &mut BTreeMap<i16, BTreeSet<SocketAddr>>,
+    map: HashMap<i32, Vec<(IpAddr, u16)>>,
+) {
+    for (dc, addrs) in map {
+        if dc == 0 {
+            continue;
+        }
+        let Ok(dc_idx) = i16::try_from(dc) else {
+            continue;
+        };
+        let entry = endpoints_by_dc.entry(dc_idx).or_default();
+        for (ip, port) in addrs {
+            entry.insert(SocketAddr::new(ip, port));
+        }
+    }
+}
+
+fn floor_mode_label(mode: MeFloorMode) -> &'static str {
+    match mode {
+        MeFloorMode::Static => "static",
+        MeFloorMode::Adaptive => "adaptive",
+    }
+}
+
+fn bind_stale_mode_label(mode: MeBindStaleMode) -> &'static str {
+    match mode {
+        MeBindStaleMode::Never => "never",
+        MeBindStaleMode::Ttl => "ttl",
+        MeBindStaleMode::Always => "always",
+    }
+}
+
+fn socks_kdf_policy_label(policy: MeSocksKdfPolicy) -> &'static str {
+    match policy {
+        MeSocksKdfPolicy::Strict => "strict",
+        MeSocksKdfPolicy::Compat => "compat",
+    }
+}
+
+fn ip_preference_label(preference: IpPreference) -> &'static str {
+    match preference {
+        IpPreference::Unknown => "unknown",
+        IpPreference::PreferV6 => "prefer_v6",
+        IpPreference::PreferV4 => "prefer_v4",
+        IpPreference::BothWork => "both",
+        IpPreference::Unavailable => "unavailable",
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::ratio_pct;
+
+    #[test]
+    fn ratio_pct_is_zero_when_denominator_is_zero() {
+        assert_eq!(ratio_pct(1, 0), 0.0);
+    }
+
+    #[test]
+    fn ratio_pct_is_capped_at_100() {
+        assert_eq!(ratio_pct(7, 3), 100.0);
+    }
+
+    #[test]
+    fn ratio_pct_reports_expected_value() {
+        assert_eq!(ratio_pct(1, 4), 25.0);
+    }
+}

src/transport/middle_proxy/pool_writer.rs

@@ -0,0 +1,535 @@
+use std::net::SocketAddr;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, AtomicU8, AtomicU64, Ordering};
+use std::time::{Duration, Instant};
+use std::io::ErrorKind;
+
+use bytes::BytesMut;
+use rand::Rng;
+use tokio::sync::mpsc;
+use tokio_util::sync::CancellationToken;
+use tracing::{debug, info, warn};
+
+use crate::config::MeBindStaleMode;
+use crate::crypto::SecureRandom;
+use crate::error::{ProxyError, Result};
+use crate::protocol::constants::{RPC_CLOSE_EXT_U32, RPC_PING_U32};
+
+use super::codec::{RpcWriter, WriterCommand};
+use super::pool::{MePool, MeWriter, WriterContour};
+use super::reader::reader_loop;
+use super::registry::BoundConn;
+use super::wire::build_proxy_req_payload;
+
+const ME_ACTIVE_PING_SECS: u64 = 25;
+const ME_ACTIVE_PING_JITTER_SECS: i64 = 5;
+const ME_IDLE_KEEPALIVE_MAX_SECS: u64 = 5;
+const ME_RPC_PROXY_REQ_RESPONSE_WAIT_MS: u64 = 700;
+
+fn is_me_peer_closed_error(error: &ProxyError) -> bool {
+    matches!(error, ProxyError::Io(ioe) if ioe.kind() == ErrorKind::UnexpectedEof)
+}
+
+impl MePool {
+    pub(crate) async fn prune_closed_writers(self: &Arc<Self>) {
+        let closed_writer_ids: Vec<u64> = {
+            let ws = self.writers.read().await;
+            ws.iter().filter(|w| w.tx.is_closed()).map(|w| w.id).collect()
+        };
+        if closed_writer_ids.is_empty() {
+            return;
+        }
+
+        for writer_id in closed_writer_ids {
+            if self.registry.is_writer_empty(writer_id).await {
+                let _ = self.remove_writer_only(writer_id).await;
+            } else {
+                let _ = self.remove_writer_and_close_clients(writer_id).await;
+            }
+        }
+    }
+
+    pub(crate) async fn connect_one(self: &Arc<Self>, addr: SocketAddr, rng: &SecureRandom) -> Result<()> {
+        self.connect_one_with_generation_contour(
+            addr,
+            rng,
+            self.current_generation(),
+            WriterContour::Active,
+        )
+        .await
+    }
+
+    pub(super) async fn connect_one_with_generation_contour(
+        self: &Arc<Self>,
+        addr: SocketAddr,
+        rng: &SecureRandom,
+        generation: u64,
+        contour: WriterContour,
+    ) -> Result<()> {
+        let secret_len = self.proxy_secret.read().await.secret.len();
+        if secret_len < 32 {
+            return Err(ProxyError::Proxy("proxy-secret too short for ME auth".into()));
+        }
+
+        let (stream, _connect_ms, upstream_egress) = self.connect_tcp(addr).await?;
+        let hs = self.handshake_only(stream, addr, upstream_egress, rng).await?;
+
+        let writer_id = self.next_writer_id.fetch_add(1, Ordering::Relaxed);
+        let contour = Arc::new(AtomicU8::new(contour.as_u8()));
+        let cancel = CancellationToken::new();
+        let degraded = Arc::new(AtomicBool::new(false));
+        let draining = Arc::new(AtomicBool::new(false));
+        let draining_started_at_epoch_secs = Arc::new(AtomicU64::new(0));
+        let allow_drain_fallback = Arc::new(AtomicBool::new(false));
+        let (tx, mut rx) = mpsc::channel::<WriterCommand>(4096);
+        let mut rpc_writer = RpcWriter {
+            writer: hs.wr,
+            key: hs.write_key,
+            iv: hs.write_iv,
+            seq_no: 0,
+            crc_mode: hs.crc_mode,
+        };
+        let cancel_wr = cancel.clone();
+        tokio::spawn(async move {
+            loop {
+                tokio::select! {
+                    cmd = rx.recv() => {
+                        match cmd {
+                            Some(WriterCommand::Data(payload)) => {
+                                if rpc_writer.send(&payload).await.is_err() { break; }
+                            }
+                            Some(WriterCommand::DataAndFlush(payload)) => {
+                                if rpc_writer.send_and_flush(&payload).await.is_err() { break; }
+                            }
+                            Some(WriterCommand::Close) | None => break,
+                        }
+                    }
+                    _ = cancel_wr.cancelled() => break,
+                }
+            }
+        });
+        let writer = MeWriter {
+            id: writer_id,
+            addr,
+            generation,
+            contour: contour.clone(),
+            created_at: Instant::now(),
+            tx: tx.clone(),
+            cancel: cancel.clone(),
+            degraded: degraded.clone(),
+            draining: draining.clone(),
+            draining_started_at_epoch_secs: draining_started_at_epoch_secs.clone(),
+            allow_drain_fallback: allow_drain_fallback.clone(),
+        };
+        self.writers.write().await.push(writer.clone());
+        self.registry.mark_writer_idle(writer_id).await;
+        self.conn_count.fetch_add(1, Ordering::Relaxed);
+        self.writer_available.notify_one();
+
+        let reg = self.registry.clone();
+        let writers_arc = self.writers_arc();
+        let ping_tracker = self.ping_tracker.clone();
+        let ping_tracker_reader = ping_tracker.clone();
+        let rtt_stats = self.rtt_stats.clone();
+        let stats_reader = self.stats.clone();
+        let stats_reader_close = self.stats.clone();
+        let stats_ping = self.stats.clone();
+        let pool = Arc::downgrade(self);
+        let cancel_ping = cancel.clone();
+        let tx_ping = tx.clone();
+        let ping_tracker_ping = ping_tracker.clone();
+        let cleanup_done = Arc::new(AtomicBool::new(false));
+        let cleanup_for_reader = cleanup_done.clone();
+        let cleanup_for_ping = cleanup_done.clone();
+        let keepalive_enabled = self.me_keepalive_enabled;
+        let keepalive_interval = self.me_keepalive_interval;
+        let keepalive_jitter = self.me_keepalive_jitter;
+        let rpc_proxy_req_every_secs = self.rpc_proxy_req_every_secs.load(Ordering::Relaxed);
+        let tx_signal = tx.clone();
+        let stats_signal = self.stats.clone();
+        let cancel_signal = cancel.clone();
+        let cleanup_for_signal = cleanup_done.clone();
+        let pool_signal = Arc::downgrade(self);
+        let keepalive_jitter_signal = self.me_keepalive_jitter;
+        let cancel_reader_token = cancel.clone();
+        let cancel_ping_token = cancel_ping.clone();
+
+        tokio::spawn(async move {
+            let res = reader_loop(
+                hs.rd,
+                hs.read_key,
+                hs.read_iv,
+                hs.crc_mode,
+                reg.clone(),
+                BytesMut::new(),
+                BytesMut::new(),
+                tx.clone(),
+                ping_tracker_reader,
+                rtt_stats.clone(),
+                stats_reader,
+                writer_id,
+                degraded.clone(),
+                cancel_reader_token.clone(),
+            )
+            .await;
+            let idle_close_by_peer = if let Err(e) = res.as_ref() {
+                is_me_peer_closed_error(e) && reg.is_writer_empty(writer_id).await
+            } else {
+                false
+            };
+            if idle_close_by_peer {
+                stats_reader_close.increment_me_idle_close_by_peer_total();
+                info!(writer_id, "ME socket closed by peer on idle writer");
+            }
+            if let Some(pool) = pool.upgrade()
+                && cleanup_for_reader
+                    .compare_exchange(false, true, Ordering::AcqRel, Ordering::Relaxed)
+                    .is_ok()
+            {
+                pool.remove_writer_and_close_clients(writer_id).await;
+            }
+            if let Err(e) = res {
+                if !idle_close_by_peer {
+                    warn!(error = %e, "ME reader ended");
+                }
+            }
+            let mut ws = writers_arc.write().await;
+            ws.retain(|w| w.id != writer_id);
+            info!(remaining = ws.len(), "Dead ME writer removed from pool");
+        });
+
+        let pool_ping = Arc::downgrade(self);
+        tokio::spawn(async move {
+            let mut ping_id: i64 = rand::random::<i64>();
+            let idle_interval_cap = Duration::from_secs(ME_IDLE_KEEPALIVE_MAX_SECS);
+            // Per-writer jittered start to avoid phase sync.
+            let startup_jitter = if keepalive_enabled {
+                let mut interval = keepalive_interval;
+                if let Some(pool) = pool_ping.upgrade() {
+                    if pool.registry.is_writer_empty(writer_id).await {
+                        interval = interval.min(idle_interval_cap);
+                    }
+                } else {
+                    return;
+                }
+                let jitter_cap_ms = interval.as_millis() / 2;
+                let effective_jitter_ms = keepalive_jitter.as_millis().min(jitter_cap_ms).max(1);
+                Duration::from_millis(rand::rng().random_range(0..=effective_jitter_ms as u64))
+            } else {
+                let jitter = rand::rng().random_range(-ME_ACTIVE_PING_JITTER_SECS..=ME_ACTIVE_PING_JITTER_SECS);
+                let wait = (ME_ACTIVE_PING_SECS as i64 + jitter).max(5) as u64;
+                Duration::from_secs(wait)
+            };
+            tokio::select! {
+                _ = cancel_ping_token.cancelled() => return,
+                _ = tokio::time::sleep(startup_jitter) => {}
+            }
+            loop {
+                let wait = if keepalive_enabled {
+                    let mut interval = keepalive_interval;
+                    if let Some(pool) = pool_ping.upgrade() {
+                        if pool.registry.is_writer_empty(writer_id).await {
+                            interval = interval.min(idle_interval_cap);
+                        }
+                    } else {
+                        break;
+                    }
+                    let jitter_cap_ms = interval.as_millis() / 2;
+                    let effective_jitter_ms = keepalive_jitter.as_millis().min(jitter_cap_ms).max(1);
+                    interval + Duration::from_millis(rand::rng().random_range(0..=effective_jitter_ms as u64))
+                } else {
+                    let jitter = rand::rng().random_range(-ME_ACTIVE_PING_JITTER_SECS..=ME_ACTIVE_PING_JITTER_SECS);
+                    let secs = (ME_ACTIVE_PING_SECS as i64 + jitter).max(5) as u64;
+                    Duration::from_secs(secs)
+                };
+                tokio::select! {
+                    _ = cancel_ping_token.cancelled() => {
+                        break;
+                    }
+                    _ = tokio::time::sleep(wait) => {}
+                }
+                let sent_id = ping_id;
+                let mut p = Vec::with_capacity(12);
+                p.extend_from_slice(&RPC_PING_U32.to_le_bytes());
+                p.extend_from_slice(&sent_id.to_le_bytes());
+                {
+                    let mut tracker = ping_tracker_ping.lock().await;
+                    let before = tracker.len();
+                    tracker.retain(|_, (ts, _)| ts.elapsed() < Duration::from_secs(120));
+                    let expired = before.saturating_sub(tracker.len());
+                    if expired > 0 {
+                        stats_ping.increment_me_keepalive_timeout_by(expired as u64);
+                    }
+                    tracker.insert(sent_id, (std::time::Instant::now(), writer_id));
+                }
+                ping_id = ping_id.wrapping_add(1);
+                stats_ping.increment_me_keepalive_sent();
+                if tx_ping.send(WriterCommand::DataAndFlush(p)).await.is_err() {
+                    stats_ping.increment_me_keepalive_failed();
+                    debug!("ME ping failed, removing dead writer");
+                    cancel_ping.cancel();
+                    if let Some(pool) = pool_ping.upgrade()
+                        && cleanup_for_ping
+                            .compare_exchange(false, true, Ordering::AcqRel, Ordering::Relaxed)
+                            .is_ok()
+                    {
+                        pool.remove_writer_and_close_clients(writer_id).await;
+                    }
+                    break;
+                }
+            }
+        });
+
+        tokio::spawn(async move {
+            if rpc_proxy_req_every_secs == 0 {
+                return;
+            }
+
+            let interval = Duration::from_secs(rpc_proxy_req_every_secs);
+            let startup_jitter_ms = {
+                let jitter_cap_ms = interval.as_millis() / 2;
+                let effective_jitter_ms = keepalive_jitter_signal
+                    .as_millis()
+                    .min(jitter_cap_ms)
+                    .max(1);
+                rand::rng().random_range(0..=effective_jitter_ms as u64)
+            };
+
+            tokio::select! {
+                _ = cancel_signal.cancelled() => return,
+                _ = tokio::time::sleep(Duration::from_millis(startup_jitter_ms)) => {}
+            }
+
+            loop {
+                let wait = {
+                    let jitter_cap_ms = interval.as_millis() / 2;
+                    let effective_jitter_ms = keepalive_jitter_signal
+                        .as_millis()
+                        .min(jitter_cap_ms)
+                        .max(1);
+                    interval + Duration::from_millis(rand::rng().random_range(0..=effective_jitter_ms as u64))
+                };
+
+                tokio::select! {
+                    _ = cancel_signal.cancelled() => break,
+                    _ = tokio::time::sleep(wait) => {}
+                }
+
+                let Some(pool) = pool_signal.upgrade() else {
+                    break;
+                };
+
+                let Some(meta) = pool.registry.get_last_writer_meta(writer_id).await else {
+                    stats_signal.increment_me_rpc_proxy_req_signal_skipped_no_meta_total();
+                    continue;
+                };
+
+                let (conn_id, mut service_rx) = pool.registry.register().await;
+                pool.registry
+                    .bind_writer(conn_id, writer_id, tx_signal.clone(), meta.clone())
+                    .await;
+
+                let payload = build_proxy_req_payload(
+                    conn_id,
+                    meta.client_addr,
+                    meta.our_addr,
+                    &[],
+                    pool.proxy_tag.as_deref(),
+                    meta.proto_flags,
+                );
+
+                if tx_signal.send(WriterCommand::DataAndFlush(payload)).await.is_err() {
+                    stats_signal.increment_me_rpc_proxy_req_signal_failed_total();
+                    let _ = pool.registry.unregister(conn_id).await;
+                    cancel_signal.cancel();
+                    if cleanup_for_signal
+                        .compare_exchange(false, true, Ordering::AcqRel, Ordering::Relaxed)
+                        .is_ok()
+                    {
+                        pool.remove_writer_and_close_clients(writer_id).await;
+                    }
+                    break;
+                }
+
+                stats_signal.increment_me_rpc_proxy_req_signal_sent_total();
+
+                if matches!(
+                    tokio::time::timeout(
+                        Duration::from_millis(ME_RPC_PROXY_REQ_RESPONSE_WAIT_MS),
+                        service_rx.recv(),
+                    )
+                    .await,
+                    Ok(Some(_))
+                ) {
+                    stats_signal.increment_me_rpc_proxy_req_signal_response_total();
+                }
+
+                let mut close_payload = Vec::with_capacity(12);
+                close_payload.extend_from_slice(&RPC_CLOSE_EXT_U32.to_le_bytes());
+                close_payload.extend_from_slice(&conn_id.to_le_bytes());
+
+                if tx_signal
+                    .send(WriterCommand::DataAndFlush(close_payload))
+                    .await
+                    .is_err()
+                {
+                    stats_signal.increment_me_rpc_proxy_req_signal_failed_total();
+                    let _ = pool.registry.unregister(conn_id).await;
+                    cancel_signal.cancel();
+                    if cleanup_for_signal
+                        .compare_exchange(false, true, Ordering::AcqRel, Ordering::Relaxed)
+                        .is_ok()
+                    {
+                        pool.remove_writer_and_close_clients(writer_id).await;
+                    }
+                    break;
+                }
+
+                stats_signal.increment_me_rpc_proxy_req_signal_close_sent_total();
+                let _ = pool.registry.unregister(conn_id).await;
+            }
+        });
+
+        Ok(())
+    }
+
+    pub(crate) async fn remove_writer_and_close_clients(self: &Arc<Self>, writer_id: u64) {
+        let conns = self.remove_writer_only(writer_id).await;
+        for bound in conns {
+            let _ = self.registry.route(bound.conn_id, super::MeResponse::Close).await;
+            let _ = self.registry.unregister(bound.conn_id).await;
+        }
+    }
+
+    async fn remove_writer_only(self: &Arc<Self>, writer_id: u64) -> Vec<BoundConn> {
+        let mut close_tx: Option<mpsc::Sender<WriterCommand>> = None;
+        let mut removed_addr: Option<SocketAddr> = None;
+        let mut removed_uptime: Option<Duration> = None;
+        let mut trigger_refill = false;
+        {
+            let mut ws = self.writers.write().await;
+            if let Some(pos) = ws.iter().position(|w| w.id == writer_id) {
+                let w = ws.remove(pos);
+                let was_draining = w.draining.load(Ordering::Relaxed);
+                if was_draining {
+                    self.stats.decrement_pool_drain_active();
+                }
+                self.stats.increment_me_writer_removed_total();
+                w.cancel.cancel();
+                removed_addr = Some(w.addr);
+                removed_uptime = Some(w.created_at.elapsed());
+                trigger_refill = !was_draining;
+                if trigger_refill {
+                    self.stats.increment_me_writer_removed_unexpected_total();
+                }
+                close_tx = Some(w.tx.clone());
+                self.conn_count.fetch_sub(1, Ordering::Relaxed);
+            }
+        }
+        if let Some(tx) = close_tx {
+            let _ = tx.send(WriterCommand::Close).await;
+        }
+        if trigger_refill
+            && let Some(addr) = removed_addr
+        {
+            if let Some(uptime) = removed_uptime {
+                self.maybe_quarantine_flapping_endpoint(addr, uptime).await;
+            }
+            self.trigger_immediate_refill(addr);
+        }
+        self.rtt_stats.lock().await.remove(&writer_id);
+        self.registry.writer_lost(writer_id).await
+    }
+
+    pub(crate) async fn mark_writer_draining_with_timeout(
+        self: &Arc<Self>,
+        writer_id: u64,
+        timeout: Option<Duration>,
+        allow_drain_fallback: bool,
+    ) {
+        let timeout = timeout.filter(|d| !d.is_zero());
+        let found = {
+            let mut ws = self.writers.write().await;
+            if let Some(w) = ws.iter_mut().find(|w| w.id == writer_id) {
+                let already_draining = w.draining.swap(true, Ordering::Relaxed);
+                w.allow_drain_fallback
+                    .store(allow_drain_fallback, Ordering::Relaxed);
+                w.draining_started_at_epoch_secs
+                    .store(Self::now_epoch_secs(), Ordering::Relaxed);
+                if !already_draining {
+                    self.stats.increment_pool_drain_active();
+                }
+                w.contour
+                    .store(WriterContour::Draining.as_u8(), Ordering::Relaxed);
+                w.draining.store(true, Ordering::Relaxed);
+                true
+            } else {
+                false
+            }
+        };
+
+        if !found {
+            return;
+        }
+
+        let timeout_secs = timeout.map(|d| d.as_secs()).unwrap_or(0);
+        debug!(
+            writer_id,
+            timeout_secs,
+            allow_drain_fallback,
+            "ME writer marked draining"
+        );
+
+        let pool = Arc::downgrade(self);
+        tokio::spawn(async move {
+            let deadline = timeout.map(|t| Instant::now() + t);
+            while let Some(p) = pool.upgrade() {
+                if let Some(deadline_at) = deadline
+                    && Instant::now() >= deadline_at
+                {
+                    warn!(writer_id, "Drain timeout, force-closing");
+                    p.stats.increment_pool_force_close_total();
+                    let _ = p.remove_writer_and_close_clients(writer_id).await;
+                    break;
+                }
+                if p.registry.is_writer_empty(writer_id).await {
+                    let _ = p.remove_writer_only(writer_id).await;
+                    break;
+                }
+                tokio::time::sleep(Duration::from_secs(1)).await;
+            }
+        });
+    }
+
+    pub(crate) async fn mark_writer_draining(self: &Arc<Self>, writer_id: u64) {
+        self.mark_writer_draining_with_timeout(writer_id, Some(Duration::from_secs(300)), false)
+            .await;
+    }
+
+    pub(super) fn writer_accepts_new_binding(&self, writer: &MeWriter) -> bool {
+        if !writer.draining.load(Ordering::Relaxed) {
+            return true;
+        }
+        if !writer.allow_drain_fallback.load(Ordering::Relaxed) {
+            return false;
+        }
+
+        match self.bind_stale_mode() {
+            MeBindStaleMode::Never => false,
+            MeBindStaleMode::Always => true,
+            MeBindStaleMode::Ttl => {
+                let ttl_secs = self.me_bind_stale_ttl_secs.load(Ordering::Relaxed);
+                if ttl_secs == 0 {
+                    return true;
+                }
+
+                let started = writer.draining_started_at_epoch_secs.load(Ordering::Relaxed);
+                if started == 0 {
+                    return false;
+                }
+
+                Self::now_epoch_secs().saturating_sub(started) <= ttl_secs
+            }
+        }
+    }
+}

src/transport/middle_proxy/reader.rs

@@ -1,4 +1,5 @@
 use std::collections::HashMap;
+use std::io::ErrorKind;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::time::Instant;
@@ -10,31 +11,33 @@ use tokio::sync::{Mutex, mpsc};
 use tokio_util::sync::CancellationToken;
 use tracing::{debug, trace, warn};
 
-use crate::crypto::{AesCbc, crc32};
+use crate::crypto::AesCbc;
 use crate::error::{ProxyError, Result};
 use crate::protocol::constants::*;
+use crate::stats::Stats;
 
-use super::codec::WriterCommand;
+use super::codec::{RpcChecksumMode, WriterCommand, rpc_crc};
+use super::registry::RouteResult;
 use super::{ConnRegistry, MeResponse};
 
 pub(crate) async fn reader_loop(
     mut rd: tokio::io::ReadHalf<TcpStream>,
     dk: [u8; 32],
     mut div: [u8; 16],
+    crc_mode: RpcChecksumMode,
     reg: Arc<ConnRegistry>,
     enc_leftover: BytesMut,
     mut dec: BytesMut,
     tx: mpsc::Sender<WriterCommand>,
     ping_tracker: Arc<Mutex<HashMap<i64, (Instant, u64)>>>,
     rtt_stats: Arc<Mutex<HashMap<u64, (f64, f64)>>>,
+    stats: Arc<Stats>,
     _writer_id: u64,
     degraded: Arc<AtomicBool>,
     cancel: CancellationToken,
 ) -> Result<()> {
     let mut raw = enc_leftover;
     let mut expected_seq: i32 = 0;
-    let mut crc_errors = 0u32;
-    let mut seq_mismatch = 0u32;
 
     loop {
         let mut tmp = [0u8; 16_384];
@@ -43,7 +46,11 @@ pub(crate) async fn reader_loop(
             _ = cancel.cancelled() => return Ok(()),
         };
         if n == 0 {
-            return Ok(());
+            stats.increment_me_reader_eof_total();
+            return Err(ProxyError::Io(std::io::Error::new(
+                ErrorKind::UnexpectedEof,
+                "ME socket closed by peer",
+            )));
         }
         raw.extend_from_slice(&tmp[..n]);
 
@@ -80,26 +87,28 @@ pub(crate) async fn reader_loop(
             let frame = dec.split_to(fl);
             let pe = fl - 4;
             let ec = u32::from_le_bytes(frame[pe..pe + 4].try_into().unwrap());
-            if crc32(&frame[..pe]) != ec {
-                warn!("CRC mismatch in data frame");
-                crc_errors += 1;
-                if crc_errors > 3 {
-                    return Err(ProxyError::Proxy("Too many CRC mismatches".into()));
-                }
-                continue;
+            let actual_crc = rpc_crc(crc_mode, &frame[..pe]);
+            if actual_crc != ec {
+                stats.increment_me_crc_mismatch();
+                warn!(
+                    frame_len = fl,
+                    expected_crc = format_args!("0x{ec:08x}"),
+                    actual_crc = format_args!("0x{actual_crc:08x}"),
+                    "CRC mismatch — CBC crypto desync, aborting ME connection"
+                );
+                return Err(ProxyError::Proxy("CRC mismatch (crypto desync)".into()));
             }
 
             let seq_no = i32::from_le_bytes(frame[4..8].try_into().unwrap());
             if seq_no != expected_seq {
+                stats.increment_me_seq_mismatch();
                 warn!(seq_no, expected = expected_seq, "ME RPC seq mismatch");
-                seq_mismatch += 1;
-                if seq_mismatch > 10 {
-                    return Err(ProxyError::Proxy("Too many seq mismatches".into()));
-                }
-                expected_seq = seq_no.wrapping_add(1);
-            } else {
-                expected_seq = expected_seq.wrapping_add(1);
+                return Err(ProxyError::SeqNoMismatch {
+                    expected: expected_seq,
+                    got: seq_no,
+                });
             }
+            expected_seq = expected_seq.wrapping_add(1);
 
             let payload = &frame[8..pe];
             if payload.len() < 4 {
@@ -115,8 +124,21 @@ pub(crate) async fn reader_loop(
                 let data = Bytes::copy_from_slice(&body[12..]);
                 trace!(cid, flags, len = data.len(), "RPC_PROXY_ANS");
 
-                let routed = reg.route(cid, MeResponse::Data { flags, data }).await;
-                if !routed {
+                let routed = reg.route_nowait(cid, MeResponse::Data { flags, data }).await;
+                if !matches!(routed, RouteResult::Routed) {
+                    match routed {
+                        RouteResult::NoConn => stats.increment_me_route_drop_no_conn(),
+                        RouteResult::ChannelClosed => stats.increment_me_route_drop_channel_closed(),
+                        RouteResult::QueueFullBase => {
+                            stats.increment_me_route_drop_queue_full();
+                            stats.increment_me_route_drop_queue_full_base();
+                        }
+                        RouteResult::QueueFullHigh => {
+                            stats.increment_me_route_drop_queue_full();
+                            stats.increment_me_route_drop_queue_full_high();
+                        }
+                        RouteResult::Routed => {}
+                    }
                     reg.unregister(cid).await;
                     send_close_conn(&tx, cid).await;
                 }
@@ -125,8 +147,21 @@ pub(crate) async fn reader_loop(
                 let cfm = u32::from_le_bytes(body[8..12].try_into().unwrap());
                 trace!(cid, cfm, "RPC_SIMPLE_ACK");
 
-                let routed = reg.route(cid, MeResponse::Ack(cfm)).await;
-                if !routed {
+                let routed = reg.route_nowait(cid, MeResponse::Ack(cfm)).await;
+                if !matches!(routed, RouteResult::Routed) {
+                    match routed {
+                        RouteResult::NoConn => stats.increment_me_route_drop_no_conn(),
+                        RouteResult::ChannelClosed => stats.increment_me_route_drop_channel_closed(),
+                        RouteResult::QueueFullBase => {
+                            stats.increment_me_route_drop_queue_full();
+                            stats.increment_me_route_drop_queue_full_base();
+                        }
+                        RouteResult::QueueFullHigh => {
+                            stats.increment_me_route_drop_queue_full();
+                            stats.increment_me_route_drop_queue_full_high();
+                        }
+                        RouteResult::Routed => {}
+                    }
                     reg.unregister(cid).await;
                     send_close_conn(&tx, cid).await;
                 }
@@ -152,6 +187,7 @@ pub(crate) async fn reader_loop(
                 }
             } else if pt == RPC_PONG_U32 && body.len() >= 8 {
                 let ping_id = i64::from_le_bytes(body[0..8].try_into().unwrap());
+                stats.increment_me_keepalive_pong();
                 if let Some((sent, wid)) = {
                     let mut guard = ping_tracker.lock().await;
                     guard.remove(&ping_id)

src/transport/middle_proxy/registry.rs

@@ -1,14 +1,30 @@
 use std::collections::{HashMap, HashSet};
 use std::net::SocketAddr;
-use std::sync::atomic::{AtomicU64, Ordering};
-use std::sync::Arc;
+use std::sync::atomic::{AtomicU8, AtomicU64, Ordering};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
-use tokio::sync::{mpsc, Mutex, RwLock};
+use tokio::sync::{mpsc, RwLock};
+use tokio::sync::mpsc::error::TrySendError;
 
 use super::codec::WriterCommand;
 use super::MeResponse;
 
+const ROUTE_CHANNEL_CAPACITY: usize = 4096;
+const ROUTE_BACKPRESSURE_BASE_TIMEOUT_MS: u64 = 25;
+const ROUTE_BACKPRESSURE_HIGH_TIMEOUT_MS: u64 = 120;
+const ROUTE_BACKPRESSURE_HIGH_WATERMARK_PCT: u8 = 80;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum RouteResult {
+    Routed,
+    NoConn,
+    ChannelClosed,
+    QueueFullBase,
+    QueueFullHigh,
+}
+
 #[derive(Clone)]
+#[allow(dead_code)]
 pub struct ConnMeta {
     pub target_dc: i16,
     pub client_addr: SocketAddr,
@@ -17,6 +33,7 @@ pub struct ConnMeta {
 }
 
 #[derive(Clone)]
+#[allow(dead_code)]
 pub struct BoundConn {
     pub conn_id: u64,
     pub meta: ConnMeta,
@@ -28,12 +45,20 @@ pub struct ConnWriter {
     pub tx: mpsc::Sender<WriterCommand>,
 }
 
+#[derive(Clone, Debug, Default)]
+pub(super) struct WriterActivitySnapshot {
+    pub bound_clients_by_writer: HashMap<u64, usize>,
+    pub active_sessions_by_target_dc: HashMap<i16, usize>,
+}
+
 struct RegistryInner {
     map: HashMap<u64, mpsc::Sender<MeResponse>>,
     writers: HashMap<u64, mpsc::Sender<WriterCommand>>,
     writer_for_conn: HashMap<u64, u64>,
     conns_for_writer: HashMap<u64, HashSet<u64>>,
     meta: HashMap<u64, ConnMeta>,
+    last_meta_for_writer: HashMap<u64, ConnMeta>,
+    writer_idle_since_epoch_secs: HashMap<u64, u64>,
 }
 
 impl RegistryInner {
@@ -44,6 +69,8 @@ impl RegistryInner {
             writer_for_conn: HashMap::new(),
             conns_for_writer: HashMap::new(),
             meta: HashMap::new(),
+            last_meta_for_writer: HashMap::new(),
+            writer_idle_since_epoch_secs: HashMap::new(),
         }
     }
 }
@@ -51,20 +78,56 @@ impl RegistryInner {
 pub struct ConnRegistry {
     inner: RwLock<RegistryInner>,
     next_id: AtomicU64,
+    route_backpressure_base_timeout_ms: AtomicU64,
+    route_backpressure_high_timeout_ms: AtomicU64,
+    route_backpressure_high_watermark_pct: AtomicU8,
 }
 
 impl ConnRegistry {
+    fn now_epoch_secs() -> u64 {
+        SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .unwrap_or_default()
+            .as_secs()
+    }
+
     pub fn new() -> Self {
         let start = rand::random::<u64>() | 1;
         Self {
             inner: RwLock::new(RegistryInner::new()),
             next_id: AtomicU64::new(start),
+            route_backpressure_base_timeout_ms: AtomicU64::new(
+                ROUTE_BACKPRESSURE_BASE_TIMEOUT_MS,
+            ),
+            route_backpressure_high_timeout_ms: AtomicU64::new(
+                ROUTE_BACKPRESSURE_HIGH_TIMEOUT_MS,
+            ),
+            route_backpressure_high_watermark_pct: AtomicU8::new(
+                ROUTE_BACKPRESSURE_HIGH_WATERMARK_PCT,
+            ),
         }
     }
 
+    pub fn update_route_backpressure_policy(
+        &self,
+        base_timeout_ms: u64,
+        high_timeout_ms: u64,
+        high_watermark_pct: u8,
+    ) {
+        let base = base_timeout_ms.max(1);
+        let high = high_timeout_ms.max(base);
+        let watermark = high_watermark_pct.clamp(1, 100);
+        self.route_backpressure_base_timeout_ms
+            .store(base, Ordering::Relaxed);
+        self.route_backpressure_high_timeout_ms
+            .store(high, Ordering::Relaxed);
+        self.route_backpressure_high_watermark_pct
+            .store(watermark, Ordering::Relaxed);
+    }
+
     pub async fn register(&self) -> (u64, mpsc::Receiver<MeResponse>) {
         let id = self.next_id.fetch_add(1, Ordering::Relaxed);
-        let (tx, rx) = mpsc::channel(1024);
+        let (tx, rx) = mpsc::channel(ROUTE_CHANNEL_CAPACITY);
         self.inner.write().await.map.insert(id, tx);
         (id, rx)
     }
@@ -75,20 +138,90 @@ impl ConnRegistry {
         inner.map.remove(&id);
         inner.meta.remove(&id);
         if let Some(writer_id) = inner.writer_for_conn.remove(&id) {
-            if let Some(set) = inner.conns_for_writer.get_mut(&writer_id) {
+            let became_empty = if let Some(set) = inner.conns_for_writer.get_mut(&writer_id) {
                 set.remove(&id);
+                set.is_empty()
+            } else {
+                false
+            };
+            if became_empty {
+                inner
+                    .writer_idle_since_epoch_secs
+                    .insert(writer_id, Self::now_epoch_secs());
             }
             return Some(writer_id);
         }
         None
     }
 
-    pub async fn route(&self, id: u64, resp: MeResponse) -> bool {
-        let inner = self.inner.read().await;
-        if let Some(tx) = inner.map.get(&id) {
-            tx.try_send(resp).is_ok()
-        } else {
-            false
+    pub async fn route(&self, id: u64, resp: MeResponse) -> RouteResult {
+        let tx = {
+            let inner = self.inner.read().await;
+            inner.map.get(&id).cloned()
+        };
+
+        let Some(tx) = tx else {
+            return RouteResult::NoConn;
+        };
+
+        match tx.try_send(resp) {
+            Ok(()) => RouteResult::Routed,
+            Err(TrySendError::Closed(_)) => RouteResult::ChannelClosed,
+            Err(TrySendError::Full(resp)) => {
+                // Absorb short bursts without dropping/closing the session immediately.
+                let base_timeout_ms =
+                    self.route_backpressure_base_timeout_ms.load(Ordering::Relaxed).max(1);
+                let high_timeout_ms = self
+                    .route_backpressure_high_timeout_ms
+                    .load(Ordering::Relaxed)
+                    .max(base_timeout_ms);
+                let high_watermark_pct = self
+                    .route_backpressure_high_watermark_pct
+                    .load(Ordering::Relaxed)
+                    .clamp(1, 100);
+                let used = ROUTE_CHANNEL_CAPACITY.saturating_sub(tx.capacity());
+                let used_pct = if ROUTE_CHANNEL_CAPACITY == 0 {
+                    100
+                } else {
+                    (used.saturating_mul(100) / ROUTE_CHANNEL_CAPACITY) as u8
+                };
+                let high_profile = used_pct >= high_watermark_pct;
+                let timeout_ms = if high_profile {
+                    high_timeout_ms
+                } else {
+                    base_timeout_ms
+                };
+                let timeout_dur = Duration::from_millis(timeout_ms);
+
+                match tokio::time::timeout(timeout_dur, tx.send(resp)).await {
+                    Ok(Ok(())) => RouteResult::Routed,
+                    Ok(Err(_)) => RouteResult::ChannelClosed,
+                    Err(_) => {
+                        if high_profile {
+                            RouteResult::QueueFullHigh
+                        } else {
+                            RouteResult::QueueFullBase
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    pub async fn route_nowait(&self, id: u64, resp: MeResponse) -> RouteResult {
+        let tx = {
+            let inner = self.inner.read().await;
+            inner.map.get(&id).cloned()
+        };
+
+        let Some(tx) = tx else {
+            return RouteResult::NoConn;
+        };
+
+        match tx.try_send(resp) {
+            Ok(()) => RouteResult::Routed,
+            Err(TrySendError::Closed(_)) => RouteResult::ChannelClosed,
+            Err(TrySendError::Full(_)) => RouteResult::QueueFullBase,
         }
     }
 
@@ -100,8 +233,10 @@ impl ConnRegistry {
         meta: ConnMeta,
     ) {
         let mut inner = self.inner.write().await;
-        inner.meta.entry(conn_id).or_insert(meta);
+        inner.meta.entry(conn_id).or_insert(meta.clone());
         inner.writer_for_conn.insert(conn_id, writer_id);
+        inner.last_meta_for_writer.insert(writer_id, meta);
+        inner.writer_idle_since_epoch_secs.remove(&writer_id);
         inner.writers.entry(writer_id).or_insert_with(|| tx.clone());
         inner
             .conns_for_writer
@@ -110,6 +245,48 @@ impl ConnRegistry {
             .insert(conn_id);
     }
 
+    pub async fn mark_writer_idle(&self, writer_id: u64) {
+        let mut inner = self.inner.write().await;
+        inner.conns_for_writer.entry(writer_id).or_insert_with(HashSet::new);
+        inner
+            .writer_idle_since_epoch_secs
+            .entry(writer_id)
+            .or_insert(Self::now_epoch_secs());
+    }
+
+    pub async fn get_last_writer_meta(&self, writer_id: u64) -> Option<ConnMeta> {
+        let inner = self.inner.read().await;
+        inner.last_meta_for_writer.get(&writer_id).cloned()
+    }
+
+    pub async fn writer_idle_since_snapshot(&self) -> HashMap<u64, u64> {
+        let inner = self.inner.read().await;
+        inner.writer_idle_since_epoch_secs.clone()
+    }
+
+    pub(super) async fn writer_activity_snapshot(&self) -> WriterActivitySnapshot {
+        let inner = self.inner.read().await;
+        let mut bound_clients_by_writer = HashMap::<u64, usize>::new();
+        let mut active_sessions_by_target_dc = HashMap::<i16, usize>::new();
+
+        for (writer_id, conn_ids) in &inner.conns_for_writer {
+            bound_clients_by_writer.insert(*writer_id, conn_ids.len());
+        }
+        for conn_meta in inner.meta.values() {
+            if conn_meta.target_dc == 0 {
+                continue;
+            }
+            *active_sessions_by_target_dc
+                .entry(conn_meta.target_dc)
+                .or_insert(0) += 1;
+        }
+
+        WriterActivitySnapshot {
+            bound_clients_by_writer,
+            active_sessions_by_target_dc,
+        }
+    }
+
     pub async fn get_writer(&self, conn_id: u64) -> Option<ConnWriter> {
         let inner = self.inner.read().await;
         let writer_id = inner.writer_for_conn.get(&conn_id).cloned()?;
@@ -117,9 +294,16 @@ impl ConnRegistry {
         Some(ConnWriter { writer_id, tx: writer })
     }
 
+    pub async fn active_conn_ids(&self) -> Vec<u64> {
+        let inner = self.inner.read().await;
+        inner.writer_for_conn.keys().copied().collect()
+    }
+
     pub async fn writer_lost(&self, writer_id: u64) -> Vec<BoundConn> {
         let mut inner = self.inner.write().await;
         inner.writers.remove(&writer_id);
+        inner.last_meta_for_writer.remove(&writer_id);
+        inner.writer_idle_since_epoch_secs.remove(&writer_id);
         let conns = inner
             .conns_for_writer
             .remove(&writer_id)
@@ -140,6 +324,7 @@ impl ConnRegistry {
         out
     }
 
+    #[allow(dead_code)]
     pub async fn get_meta(&self, conn_id: u64) -> Option<ConnMeta> {
         let inner = self.inner.read().await;
         inner.meta.get(&conn_id).cloned()
@@ -154,3 +339,70 @@ impl ConnRegistry {
             .unwrap_or(true)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+
+    use super::ConnMeta;
+    use super::ConnRegistry;
+
+    #[tokio::test]
+    async fn writer_activity_snapshot_tracks_writer_and_dc_load() {
+        let registry = ConnRegistry::new();
+
+        let (conn_a, _rx_a) = registry.register().await;
+        let (conn_b, _rx_b) = registry.register().await;
+        let (conn_c, _rx_c) = registry.register().await;
+        let (writer_tx_a, _writer_rx_a) = tokio::sync::mpsc::channel(8);
+        let (writer_tx_b, _writer_rx_b) = tokio::sync::mpsc::channel(8);
+
+        let addr = SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 443);
+        registry
+            .bind_writer(
+                conn_a,
+                10,
+                writer_tx_a.clone(),
+                ConnMeta {
+                    target_dc: 2,
+                    client_addr: addr,
+                    our_addr: addr,
+                    proto_flags: 0,
+                },
+            )
+            .await;
+        registry
+            .bind_writer(
+                conn_b,
+                10,
+                writer_tx_a,
+                ConnMeta {
+                    target_dc: -2,
+                    client_addr: addr,
+                    our_addr: addr,
+                    proto_flags: 0,
+                },
+            )
+            .await;
+        registry
+            .bind_writer(
+                conn_c,
+                20,
+                writer_tx_b,
+                ConnMeta {
+                    target_dc: 4,
+                    client_addr: addr,
+                    our_addr: addr,
+                    proto_flags: 0,
+                },
+            )
+            .await;
+
+        let snapshot = registry.writer_activity_snapshot().await;
+        assert_eq!(snapshot.bound_clients_by_writer.get(&10), Some(&2));
+        assert_eq!(snapshot.bound_clients_by_writer.get(&20), Some(&1));
+        assert_eq!(snapshot.active_sessions_by_target_dc.get(&2), Some(&1));
+        assert_eq!(snapshot.active_sessions_by_target_dc.get(&-2), Some(&1));
+        assert_eq!(snapshot.active_sessions_by_target_dc.get(&4), Some(&1));
+    }
+}