ServerHello fixes + Docker Health-Check + Conntrack Control for Docker: merge pull request #717 from telemt/flow

ServerHello fixes + Docker Health-Check + Conntrack Control for Docker

Cargo.lock

@@ -2780,7 +2780,7 @@ checksum = "7b2093cf4c8eb1e67749a6762251bc9cd836b6fc171623bd0a9d324d37af2417"
 
 [[package]]
 name = "telemt"
-version = "3.4.1"
+version = "3.4.3"
 dependencies = [
  "aes",
  "anyhow",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "telemt"
-version = "3.4.1"
+version = "3.4.3"
 edition = "2024"
 
 [features]

Dockerfile

@@ -77,6 +77,34 @@ COPY config.toml /app/config.toml
 
 EXPOSE 443 9090 9091
 
+HEALTHCHECK --interval=30s --timeout=5s --start-period=20s --retries=3 CMD ["/app/telemt", "healthcheck", "/app/config.toml", "--mode", "liveness"]
+
+ENTRYPOINT ["/app/telemt"]
+CMD ["config.toml"]
+
+# ==========================
+# Production Netfilter Profile
+# ==========================
+FROM debian:12-slim AS prod-netfilter
+
+RUN set -eux; \
+    apt-get update; \
+    apt-get install -y --no-install-recommends \
+        ca-certificates \
+        conntrack \
+        nftables \
+        iptables; \
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY --from=minimal /telemt /app/telemt
+COPY config.toml /app/config.toml
+
+EXPOSE 443 9090 9091
+
+HEALTHCHECK --interval=30s --timeout=5s --start-period=20s --retries=3 CMD ["/app/telemt", "healthcheck", "/app/config.toml", "--mode", "liveness"]
+
 ENTRYPOINT ["/app/telemt"]
 CMD ["config.toml"]
 
@@ -94,5 +122,7 @@ USER nonroot:nonroot
 
 EXPOSE 443 9090 9091
 
+HEALTHCHECK --interval=30s --timeout=5s --start-period=20s --retries=3 CMD ["/app/telemt", "healthcheck", "/app/config.toml", "--mode", "liveness"]
+
 ENTRYPOINT ["/app/telemt"]
 CMD ["config.toml"]

docker-compose.host-netfilter.yml

@@ -0,0 +1,10 @@
+services:
+  telemt:
+    build:
+      context: .
+      target: prod-netfilter
+    network_mode: host
+    ports: []
+    cap_add:
+      - NET_BIND_SERVICE
+      - NET_ADMIN

docker-compose.netfilter.yml

@@ -0,0 +1,8 @@
+services:
+  telemt:
+    build:
+      context: .
+      target: prod-netfilter
+    cap_add:
+      - NET_BIND_SERVICE
+      - NET_ADMIN

docker-compose.yml

@@ -1,7 +1,9 @@
 services:
   telemt:
     image: ghcr.io/telemt/telemt:latest
-    build: .
+    build:
+      context: .
+      target: prod
     container_name: telemt
     restart: unless-stopped
     ports:
@@ -16,13 +18,18 @@ services:
       - /etc/telemt:rw,mode=1777,size=4m
     environment:
       - RUST_LOG=info
+    healthcheck:
+      test: [ "CMD", "/app/telemt", "healthcheck", "/etc/telemt/config.toml", "--mode", "liveness" ]
+      interval: 30s
+      timeout: 5s
+      retries: 3
+      start_period: 20s
     # Uncomment this line if you want to use host network for IPv6, but bridge is default and usually better
     # network_mode: host
     cap_drop:
       - ALL
     cap_add:
       - NET_BIND_SERVICE
-      - NET_ADMIN
     read_only: true
     security_opt:
       - no-new-privileges:true

src/api/mod.rs

@@ -41,8 +41,8 @@ use config_store::{current_revision, load_config_from_disk, parse_if_match};
 use events::ApiEventStore;
 use http_utils::{error_response, read_json, read_optional_json, success_response};
 use model::{
-    ApiFailure, CreateUserRequest, DeleteUserResponse, HealthData, PatchUserRequest,
-    RotateSecretRequest, SummaryData, UserActiveIps,
+    ApiFailure, CreateUserRequest, DeleteUserResponse, HealthData, HealthReadyData,
+    PatchUserRequest, RotateSecretRequest, SummaryData, UserActiveIps,
 };
 use runtime_edge::{
     EdgeConnectionsCacheEntry, build_runtime_connections_summary_data,
@@ -275,6 +275,33 @@ async fn handle(
                 };
                 Ok(success_response(StatusCode::OK, data, revision))
             }
+            ("GET", "/v1/health/ready") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let admission_open = shared.runtime_state.admission_open.load(Ordering::Relaxed);
+                let upstream_health = shared.upstream_manager.api_health_summary().await;
+                let ready = admission_open && upstream_health.healthy_total > 0;
+                let reason = if ready {
+                    None
+                } else if !admission_open {
+                    Some("admission_closed")
+                } else {
+                    Some("no_healthy_upstreams")
+                };
+                let data = HealthReadyData {
+                    ready,
+                    status: if ready { "ready" } else { "not_ready" },
+                    reason,
+                    admission_open,
+                    healthy_upstreams: upstream_health.healthy_total,
+                    total_upstreams: upstream_health.configured_total,
+                };
+                let status_code = if ready {
+                    StatusCode::OK
+                } else {
+                    StatusCode::SERVICE_UNAVAILABLE
+                };
+                Ok(success_response(status_code, 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);

src/api/model.rs

@@ -60,6 +60,17 @@ pub(super) struct HealthData {
     pub(super) read_only: bool,
 }
 
+#[derive(Serialize)]
+pub(super) struct HealthReadyData {
+    pub(super) ready: bool,
+    pub(super) status: &'static str,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(super) reason: Option<&'static str>,
+    pub(super) admission_open: bool,
+    pub(super) healthy_upstreams: usize,
+    pub(super) total_upstreams: usize,
+}
+
 #[derive(Serialize)]
 pub(super) struct SummaryData {
     pub(super) uptime_seconds: f64,

src/cli.rs

@@ -6,12 +6,15 @@
 //! - `reload [--pid-file PATH]` - Reload configuration (SIGHUP)
 //! - `status [--pid-file PATH]` - Check daemon status
 //! - `run [OPTIONS] [config.toml]` - Run in foreground (default behavior)
+//! - `healthcheck [OPTIONS] [config.toml]` - Run control-plane health probe
 
 use rand::RngExt;
 use std::fs;
 use std::path::{Path, PathBuf};
 use std::process::Command;
 
+use crate::healthcheck::{self, HealthcheckMode};
+
 #[cfg(unix)]
 use crate::daemon::{self, DEFAULT_PID_FILE, DaemonOptions};
 
@@ -28,6 +31,8 @@ pub enum Subcommand {
     Reload,
     /// Check daemon status (`status` subcommand).
     Status,
+    /// Run health probe and exit with status code.
+    Healthcheck,
     /// Fire-and-forget setup (`--init`).
     Init,
 }
@@ -38,6 +43,8 @@ pub struct ParsedCommand {
     pub subcommand: Subcommand,
     pub pid_file: PathBuf,
     pub config_path: String,
+    pub healthcheck_mode: HealthcheckMode,
+    pub healthcheck_mode_invalid: Option<String>,
     #[cfg(unix)]
     pub daemon_opts: DaemonOptions,
     pub init_opts: Option<InitOptions>,
@@ -52,6 +59,8 @@ impl Default for ParsedCommand {
             #[cfg(not(unix))]
             pid_file: PathBuf::from("/var/run/telemt.pid"),
             config_path: "config.toml".to_string(),
+            healthcheck_mode: HealthcheckMode::Liveness,
+            healthcheck_mode_invalid: None,
             #[cfg(unix)]
             daemon_opts: DaemonOptions::default(),
             init_opts: None,
@@ -91,6 +100,9 @@ pub fn parse_command(args: &[String]) -> ParsedCommand {
             "status" => {
                 cmd.subcommand = Subcommand::Status;
             }
+            "healthcheck" => {
+                cmd.subcommand = Subcommand::Healthcheck;
+            }
             "run" => {
                 cmd.subcommand = Subcommand::Run;
                 #[cfg(unix)]
@@ -113,7 +125,35 @@ pub fn parse_command(args: &[String]) -> ParsedCommand {
     while i < args.len() {
         match args[i].as_str() {
             // Skip subcommand names
-            "start" | "stop" | "reload" | "status" | "run" => {}
+            "start" | "stop" | "reload" | "status" | "run" | "healthcheck" => {}
+            "--mode" => {
+                i += 1;
+                if i < args.len() {
+                    match HealthcheckMode::from_cli_arg(&args[i]) {
+                        Some(mode) => {
+                            cmd.healthcheck_mode = mode;
+                            cmd.healthcheck_mode_invalid = None;
+                        }
+                        None => {
+                            cmd.healthcheck_mode_invalid = Some(args[i].clone());
+                        }
+                    }
+                } else {
+                    cmd.healthcheck_mode_invalid = Some(String::new());
+                }
+            }
+            s if s.starts_with("--mode=") => {
+                let raw = s.trim_start_matches("--mode=");
+                match HealthcheckMode::from_cli_arg(raw) {
+                    Some(mode) => {
+                        cmd.healthcheck_mode = mode;
+                        cmd.healthcheck_mode_invalid = None;
+                    }
+                    None => {
+                        cmd.healthcheck_mode_invalid = Some(raw.to_string());
+                    }
+                }
+            }
             // PID file option (for stop/reload/status)
             "--pid-file" => {
                 i += 1;
@@ -152,6 +192,20 @@ pub fn execute_subcommand(cmd: &ParsedCommand) -> Option<i32> {
         Subcommand::Stop => Some(cmd_stop(&cmd.pid_file)),
         Subcommand::Reload => Some(cmd_reload(&cmd.pid_file)),
         Subcommand::Status => Some(cmd_status(&cmd.pid_file)),
+        Subcommand::Healthcheck => {
+            if let Some(invalid_mode) = cmd.healthcheck_mode_invalid.as_ref() {
+                if invalid_mode.is_empty() {
+                    eprintln!("[telemt] Missing value for --mode (supported: liveness, ready)");
+                } else {
+                    eprintln!(
+                        "[telemt] Invalid --mode value '{invalid_mode}' (supported: liveness, ready)"
+                    );
+                }
+                Some(2)
+            } else {
+                Some(healthcheck::run(&cmd.config_path, cmd.healthcheck_mode))
+            }
+        }
         Subcommand::Init => {
             if let Some(opts) = cmd.init_opts.clone() {
                 match run_init(opts) {
@@ -177,6 +231,20 @@ pub fn execute_subcommand(cmd: &ParsedCommand) -> Option<i32> {
             eprintln!("[telemt] Subcommand not supported on this platform");
             Some(1)
         }
+        Subcommand::Healthcheck => {
+            if let Some(invalid_mode) = cmd.healthcheck_mode_invalid.as_ref() {
+                if invalid_mode.is_empty() {
+                    eprintln!("[telemt] Missing value for --mode (supported: liveness, ready)");
+                } else {
+                    eprintln!(
+                        "[telemt] Invalid --mode value '{invalid_mode}' (supported: liveness, ready)"
+                    );
+                }
+                Some(2)
+            } else {
+                Some(healthcheck::run(&cmd.config_path, cmd.healthcheck_mode))
+            }
+        }
         Subcommand::Init => {
             if let Some(opts) = cmd.init_opts.clone() {
                 match run_init(opts) {

src/config/load.rs

@@ -343,6 +343,10 @@ impl ProxyConfig {
         let network_table = parsed_toml
             .get("network")
             .and_then(|value| value.as_table());
+        let server_table = parsed_toml.get("server").and_then(|value| value.as_table());
+        let conntrack_control_table = server_table
+            .and_then(|table| table.get("conntrack_control"))
+            .and_then(|value| value.as_table());
         let update_every_is_explicit = general_table
             .map(|table| table.contains_key("update_every"))
             .unwrap_or(false);
@@ -372,10 +376,17 @@ impl ProxyConfig {
         let stun_servers_is_explicit = network_table
             .map(|table| table.contains_key("stun_servers"))
             .unwrap_or(false);
+        let inline_conntrack_control_is_explicit = conntrack_control_table
+            .map(|table| table.contains_key("inline_conntrack_control"))
+            .unwrap_or(false);
 
         let mut config: ProxyConfig = parsed_toml
             .try_into()
             .map_err(|e| ProxyError::Config(e.to_string()))?;
+        config
+            .server
+            .conntrack_control
+            .inline_conntrack_control_explicit = inline_conntrack_control_is_explicit;
 
         if !update_every_is_explicit && (legacy_secret_is_explicit || legacy_config_is_explicit) {
             config.general.update_every = None;
@@ -1881,6 +1892,43 @@ mod tests {
         );
     }
 
+    #[test]
+    fn conntrack_inline_explicit_flag_is_false_when_omitted() {
+        let cfg = load_config_from_temp_toml(
+            r#"
+            [general]
+            [network]
+            [server]
+            [server.conntrack_control]
+            [access]
+            "#,
+        );
+        assert!(
+            !cfg.server
+                .conntrack_control
+                .inline_conntrack_control_explicit
+        );
+    }
+
+    #[test]
+    fn conntrack_inline_explicit_flag_is_true_when_present() {
+        let cfg = load_config_from_temp_toml(
+            r#"
+            [general]
+            [network]
+            [server]
+            [server.conntrack_control]
+            inline_conntrack_control = true
+            [access]
+            "#,
+        );
+        assert!(
+            cfg.server
+                .conntrack_control
+                .inline_conntrack_control_explicit
+        );
+    }
+
     #[test]
     fn unknown_sni_action_parses_and_defaults_to_drop() {
         let cfg_default: ProxyConfig = toml::from_str(

src/config/types.rs

@@ -1329,6 +1329,10 @@ pub struct ConntrackControlConfig {
     #[serde(default = "default_conntrack_control_enabled")]
     pub inline_conntrack_control: bool,
 
+    /// Tracks whether inline_conntrack_control was explicitly set in config.
+    #[serde(skip)]
+    pub inline_conntrack_control_explicit: bool,
+
     /// Conntrack mode for listener ingress traffic.
     #[serde(default)]
     pub mode: ConntrackMode,
@@ -1363,6 +1367,7 @@ impl Default for ConntrackControlConfig {
     fn default() -> Self {
         Self {
             inline_conntrack_control: default_conntrack_control_enabled(),
+            inline_conntrack_control_explicit: false,
             mode: ConntrackMode::default(),
             backend: ConntrackBackend::default(),
             profile: ConntrackPressureProfile::default(),

src/conntrack_control.rs

@@ -24,6 +24,13 @@ enum NetfilterBackend {
     Iptables,
 }
 
+#[derive(Clone, Copy)]
+struct ConntrackRuntimeSupport {
+    netfilter_backend: Option<NetfilterBackend>,
+    has_cap_net_admin: bool,
+    has_conntrack_binary: bool,
+}
+
 #[derive(Clone, Copy)]
 struct PressureSample {
     conn_pct: Option<u8>,
@@ -56,11 +63,8 @@ pub(crate) fn spawn_conntrack_controller(
     shared: Arc<ProxySharedState>,
 ) {
     if !cfg!(target_os = "linux") {
-        let enabled = config_rx
-            .borrow()
-            .server
-            .conntrack_control
-            .inline_conntrack_control;
+        let cfg = config_rx.borrow();
+        let enabled = cfg.server.conntrack_control.inline_conntrack_control;
         stats.set_conntrack_control_enabled(enabled);
         stats.set_conntrack_control_available(false);
         stats.set_conntrack_pressure_active(false);
@@ -68,9 +72,14 @@ pub(crate) fn spawn_conntrack_controller(
         stats.set_conntrack_rule_apply_ok(false);
         shared.disable_conntrack_close_sender();
         shared.set_conntrack_pressure_active(false);
-        if enabled {
+        if enabled
+            && cfg
+                .server
+                .conntrack_control
+                .inline_conntrack_control_explicit
+        {
             warn!(
-                "conntrack control is configured but unsupported on this OS; disabling runtime worker"
+                "conntrack control explicitly enabled but unsupported on this OS; disabling runtime worker"
             );
         }
         return;
@@ -92,16 +101,17 @@ async fn run_conntrack_controller(
     let mut cfg = config_rx.borrow().clone();
     let mut pressure_state = PressureState::new(stats.as_ref());
     let mut delete_budget_tokens = cfg.server.conntrack_control.delete_budget_per_sec;
-    let mut backend = pick_backend(cfg.server.conntrack_control.backend);
+    let mut runtime_support = probe_runtime_support(cfg.server.conntrack_control.backend);
+    let mut effective_enabled = effective_conntrack_enabled(&cfg, runtime_support);
 
     apply_runtime_state(
         stats.as_ref(),
         shared.as_ref(),
         &cfg,
-        backend.is_some(),
+        runtime_support,
         false,
     );
-    reconcile_rules(&cfg, backend, stats.as_ref()).await;
+    reconcile_rules(&cfg, runtime_support, stats.as_ref()).await;
 
     loop {
         tokio::select! {
@@ -110,17 +120,18 @@ async fn run_conntrack_controller(
                     break;
                 }
                 cfg = config_rx.borrow_and_update().clone();
-                backend = pick_backend(cfg.server.conntrack_control.backend);
+                runtime_support = probe_runtime_support(cfg.server.conntrack_control.backend);
+                effective_enabled = effective_conntrack_enabled(&cfg, runtime_support);
                 delete_budget_tokens = cfg.server.conntrack_control.delete_budget_per_sec;
-                apply_runtime_state(stats.as_ref(), shared.as_ref(), &cfg, backend.is_some(), pressure_state.active);
-                reconcile_rules(&cfg, backend, stats.as_ref()).await;
+                apply_runtime_state(stats.as_ref(), shared.as_ref(), &cfg, runtime_support, pressure_state.active);
+                reconcile_rules(&cfg, runtime_support, stats.as_ref()).await;
             }
             event = close_rx.recv() => {
                 let Some(event) = event else {
                     break;
                 };
                 stats.set_conntrack_event_queue_depth(close_rx.len() as u64);
-                if !cfg.server.conntrack_control.inline_conntrack_control {
+                if !effective_enabled {
                     continue;
                 }
                 if !pressure_state.active {
@@ -156,6 +167,7 @@ async fn run_conntrack_controller(
                     stats.as_ref(),
                     shared.as_ref(),
                     &cfg,
+                    effective_enabled,
                     &sample,
                     &mut pressure_state,
                 );
@@ -175,20 +187,30 @@ fn apply_runtime_state(
     stats: &Stats,
     shared: &ProxySharedState,
     cfg: &ProxyConfig,
-    backend_available: bool,
+    runtime_support: ConntrackRuntimeSupport,
     pressure_active: bool,
 ) {
     let enabled = cfg.server.conntrack_control.inline_conntrack_control;
-    let available = enabled && backend_available && has_cap_net_admin();
-    if enabled && !available {
+    let available = effective_conntrack_enabled(cfg, runtime_support);
+    if enabled
+        && !available
+        && cfg
+            .server
+            .conntrack_control
+            .inline_conntrack_control_explicit
+    {
         warn!(
-            "conntrack control enabled but unavailable (missing CAP_NET_ADMIN or backend binaries)"
+            has_cap_net_admin = runtime_support.has_cap_net_admin,
+            backend_available = runtime_support.netfilter_backend.is_some(),
+            conntrack_binary_available = runtime_support.has_conntrack_binary,
+            configured_backend = ?cfg.server.conntrack_control.backend,
+            "conntrack control explicitly enabled but unavailable; disabling runtime features"
         );
     }
     stats.set_conntrack_control_enabled(enabled);
     stats.set_conntrack_control_available(available);
-    shared.set_conntrack_pressure_active(enabled && pressure_active);
-    stats.set_conntrack_pressure_active(enabled && pressure_active);
+    shared.set_conntrack_pressure_active(available && pressure_active);
+    stats.set_conntrack_pressure_active(available && pressure_active);
 }
 
 fn collect_pressure_sample(
@@ -228,10 +250,11 @@ fn update_pressure_state(
     stats: &Stats,
     shared: &ProxySharedState,
     cfg: &ProxyConfig,
+    effective_enabled: bool,
     sample: &PressureSample,
     state: &mut PressureState,
 ) {
-    if !cfg.server.conntrack_control.inline_conntrack_control {
+    if !effective_enabled {
         if state.active {
             state.active = false;
             state.low_streak = 0;
@@ -285,22 +308,26 @@ fn update_pressure_state(
     state.low_streak = 0;
 }
 
-async fn reconcile_rules(cfg: &ProxyConfig, backend: Option<NetfilterBackend>, stats: &Stats) {
+async fn reconcile_rules(
+    cfg: &ProxyConfig,
+    runtime_support: ConntrackRuntimeSupport,
+    stats: &Stats,
+) {
     if !cfg.server.conntrack_control.inline_conntrack_control {
         clear_notrack_rules_all_backends().await;
         stats.set_conntrack_rule_apply_ok(true);
         return;
     }
 
-    if !has_cap_net_admin() {
+    if !effective_conntrack_enabled(cfg, runtime_support) {
+        clear_notrack_rules_all_backends().await;
         stats.set_conntrack_rule_apply_ok(false);
         return;
     }
 
-    let Some(backend) = backend else {
-        stats.set_conntrack_rule_apply_ok(false);
-        return;
-    };
+    let backend = runtime_support
+        .netfilter_backend
+        .expect("netfilter backend must be available for effective conntrack control");
 
     let apply_result = match backend {
         NetfilterBackend::Nftables => apply_nft_rules(cfg).await,
@@ -315,6 +342,24 @@ async fn reconcile_rules(cfg: &ProxyConfig, backend: Option<NetfilterBackend>, s
     }
 }
 
+fn probe_runtime_support(configured_backend: ConntrackBackend) -> ConntrackRuntimeSupport {
+    ConntrackRuntimeSupport {
+        netfilter_backend: pick_backend(configured_backend),
+        has_cap_net_admin: has_cap_net_admin(),
+        has_conntrack_binary: command_exists("conntrack"),
+    }
+}
+
+fn effective_conntrack_enabled(
+    cfg: &ProxyConfig,
+    runtime_support: ConntrackRuntimeSupport,
+) -> bool {
+    cfg.server.conntrack_control.inline_conntrack_control
+        && runtime_support.has_cap_net_admin
+        && runtime_support.netfilter_backend.is_some()
+        && runtime_support.has_conntrack_binary
+}
+
 fn pick_backend(configured: ConntrackBackend) -> Option<NetfilterBackend> {
     match configured {
         ConntrackBackend::Auto => {
@@ -710,7 +755,7 @@ mod tests {
             me_queue_pressure_delta: 0,
         };
 
-        update_pressure_state(&stats, shared.as_ref(), &cfg, &sample, &mut state);
+        update_pressure_state(&stats, shared.as_ref(), &cfg, true, &sample, &mut state);
 
         assert!(state.active);
         assert!(shared.conntrack_pressure_active());
@@ -731,7 +776,14 @@ mod tests {
             accept_timeout_delta: 0,
             me_queue_pressure_delta: 0,
         };
-        update_pressure_state(&stats, shared.as_ref(), &cfg, &high_sample, &mut state);
+        update_pressure_state(
+            &stats,
+            shared.as_ref(),
+            &cfg,
+            true,
+            &high_sample,
+            &mut state,
+        );
         assert!(state.active);
 
         let low_sample = PressureSample {
@@ -740,11 +792,11 @@ mod tests {
             accept_timeout_delta: 0,
             me_queue_pressure_delta: 0,
         };
-        update_pressure_state(&stats, shared.as_ref(), &cfg, &low_sample, &mut state);
+        update_pressure_state(&stats, shared.as_ref(), &cfg, true, &low_sample, &mut state);
         assert!(state.active);
-        update_pressure_state(&stats, shared.as_ref(), &cfg, &low_sample, &mut state);
+        update_pressure_state(&stats, shared.as_ref(), &cfg, true, &low_sample, &mut state);
         assert!(state.active);
-        update_pressure_state(&stats, shared.as_ref(), &cfg, &low_sample, &mut state);
+        update_pressure_state(&stats, shared.as_ref(), &cfg, true, &low_sample, &mut state);
 
         assert!(!state.active);
         assert!(!shared.conntrack_pressure_active());
@@ -765,7 +817,7 @@ mod tests {
             me_queue_pressure_delta: 10,
         };
 
-        update_pressure_state(&stats, shared.as_ref(), &cfg, &sample, &mut state);
+        update_pressure_state(&stats, shared.as_ref(), &cfg, false, &sample, &mut state);
 
         assert!(!state.active);
         assert!(!shared.conntrack_pressure_active());

src/healthcheck.rs

@@ -0,0 +1,211 @@
+use std::io::{Read, Write};
+use std::net::{Ipv4Addr, Ipv6Addr, SocketAddr, TcpStream};
+use std::time::Duration;
+
+use serde_json::Value;
+
+use crate::config::ProxyConfig;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) enum HealthcheckMode {
+    Liveness,
+    Ready,
+}
+
+impl HealthcheckMode {
+    pub(crate) fn from_cli_arg(value: &str) -> Option<Self> {
+        match value {
+            "liveness" => Some(Self::Liveness),
+            "ready" => Some(Self::Ready),
+            _ => None,
+        }
+    }
+
+    fn request_path(self) -> &'static str {
+        match self {
+            Self::Liveness => "/v1/health",
+            Self::Ready => "/v1/health/ready",
+        }
+    }
+}
+
+pub(crate) fn run(config_path: &str, mode: HealthcheckMode) -> i32 {
+    match run_inner(config_path, mode) {
+        Ok(()) => 0,
+        Err(error) => {
+            eprintln!("[telemt] healthcheck failed: {error}");
+            1
+        }
+    }
+}
+
+fn run_inner(config_path: &str, mode: HealthcheckMode) -> Result<(), String> {
+    let config =
+        ProxyConfig::load(config_path).map_err(|error| format!("config load failed: {error}"))?;
+    let api_cfg = &config.server.api;
+    if !api_cfg.enabled {
+        return Ok(());
+    }
+
+    let listen: SocketAddr = api_cfg
+        .listen
+        .parse()
+        .map_err(|_| format!("invalid API listen address: {}", api_cfg.listen))?;
+    if listen.port() == 0 {
+        return Err("API listen port is 0".to_string());
+    }
+    let target = probe_target(listen);
+
+    let mut stream = TcpStream::connect_timeout(&target, Duration::from_secs(2))
+        .map_err(|error| format!("connect {target} failed: {error}"))?;
+    stream
+        .set_read_timeout(Some(Duration::from_secs(2)))
+        .map_err(|error| format!("set read timeout failed: {error}"))?;
+    stream
+        .set_write_timeout(Some(Duration::from_secs(2)))
+        .map_err(|error| format!("set write timeout failed: {error}"))?;
+
+    let request = build_request(target, mode.request_path(), &api_cfg.auth_header);
+    stream
+        .write_all(request.as_bytes())
+        .map_err(|error| format!("request write failed: {error}"))?;
+    stream
+        .flush()
+        .map_err(|error| format!("request flush failed: {error}"))?;
+
+    let mut raw_response = Vec::new();
+    stream
+        .read_to_end(&mut raw_response)
+        .map_err(|error| format!("response read failed: {error}"))?;
+    let response =
+        String::from_utf8(raw_response).map_err(|_| "response is not valid UTF-8".to_string())?;
+
+    let (status_code, body) = split_response(&response)?;
+    if status_code != 200 {
+        return Err(format!("HTTP status {status_code}"));
+    }
+
+    validate_payload(mode, body)?;
+    Ok(())
+}
+
+fn probe_target(listen: SocketAddr) -> SocketAddr {
+    match listen {
+        SocketAddr::V4(addr) => {
+            let ip = if addr.ip().is_unspecified() {
+                Ipv4Addr::LOCALHOST
+            } else {
+                *addr.ip()
+            };
+            SocketAddr::from((ip, addr.port()))
+        }
+        SocketAddr::V6(addr) => {
+            let ip = if addr.ip().is_unspecified() {
+                Ipv6Addr::LOCALHOST
+            } else {
+                *addr.ip()
+            };
+            SocketAddr::from((ip, addr.port()))
+        }
+    }
+}
+
+fn build_request(target: SocketAddr, path: &str, auth_header: &str) -> String {
+    let mut request = format!(
+        "GET {path} HTTP/1.1\r\nHost: {}\r\nConnection: close\r\n",
+        target
+    );
+    if !auth_header.is_empty() {
+        request.push_str("Authorization: ");
+        request.push_str(auth_header);
+        request.push_str("\r\n");
+    }
+    request.push_str("\r\n");
+    request
+}
+
+fn split_response(response: &str) -> Result<(u16, &str), String> {
+    let header_end = response
+        .find("\r\n\r\n")
+        .ok_or_else(|| "invalid HTTP response headers".to_string())?;
+    let header = &response[..header_end];
+    let body = &response[header_end + 4..];
+    let status_line = header
+        .lines()
+        .next()
+        .ok_or_else(|| "missing HTTP status line".to_string())?;
+    let status_code = parse_status_code(status_line)?;
+    Ok((status_code, body))
+}
+
+fn parse_status_code(status_line: &str) -> Result<u16, String> {
+    let mut parts = status_line.split_whitespace();
+    let version = parts
+        .next()
+        .ok_or_else(|| "missing HTTP version".to_string())?;
+    if !version.starts_with("HTTP/") {
+        return Err(format!("invalid HTTP status line: {status_line}"));
+    }
+    let code = parts
+        .next()
+        .ok_or_else(|| "missing HTTP status code".to_string())?;
+    code.parse::<u16>()
+        .map_err(|_| format!("invalid HTTP status code: {code}"))
+}
+
+fn validate_payload(mode: HealthcheckMode, body: &str) -> Result<(), String> {
+    let payload: Value =
+        serde_json::from_str(body).map_err(|_| "response body is not valid JSON".to_string())?;
+    if payload.get("ok").and_then(Value::as_bool) != Some(true) {
+        return Err("response JSON has ok=false".to_string());
+    }
+
+    let data = payload
+        .get("data")
+        .ok_or_else(|| "response JSON has no data field".to_string())?;
+    match mode {
+        HealthcheckMode::Liveness => {
+            if data.get("status").and_then(Value::as_str) != Some("ok") {
+                return Err("liveness status is not ok".to_string());
+            }
+        }
+        HealthcheckMode::Ready => {
+            if data.get("ready").and_then(Value::as_bool) != Some(true) {
+                return Err("readiness flag is false".to_string());
+            }
+        }
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{HealthcheckMode, parse_status_code, split_response, validate_payload};
+
+    #[test]
+    fn parse_status_code_reads_http_200() {
+        let status = parse_status_code("HTTP/1.1 200 OK").expect("must parse status");
+        assert_eq!(status, 200);
+    }
+
+    #[test]
+    fn split_response_extracts_status_and_body() {
+        let response = "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"ok\":true}";
+        let (status, body) = split_response(response).expect("must split response");
+        assert_eq!(status, 200);
+        assert_eq!(body, "{\"ok\":true}");
+    }
+
+    #[test]
+    fn validate_payload_accepts_liveness_contract() {
+        let body = "{\"ok\":true,\"data\":{\"status\":\"ok\"}}";
+        validate_payload(HealthcheckMode::Liveness, body).expect("liveness payload must pass");
+    }
+
+    #[test]
+    fn validate_payload_rejects_not_ready() {
+        let body = "{\"ok\":true,\"data\":{\"ready\":false}}";
+        let result = validate_payload(HealthcheckMode::Ready, body);
+        assert!(result.is_err());
+    }
+}

src/main.rs

@@ -8,6 +8,7 @@ mod crypto;
 #[cfg(unix)]
 mod daemon;
 mod error;
+mod healthcheck;
 mod ip_tracker;
 #[cfg(test)]
 #[path = "tests/ip_tracker_encapsulation_adversarial_tests.rs"]

src/tls_front/emulator.rs

@@ -66,9 +66,19 @@ fn ensure_payload_capacity(mut sizes: Vec<usize>, payload_len: usize) -> Vec<usi
 fn emulated_app_data_sizes(cached: &CachedTlsData) -> Vec<usize> {
     match cached.behavior_profile.source {
         TlsProfileSource::Raw | TlsProfileSource::Merged => {
-            if !cached.behavior_profile.app_data_record_sizes.is_empty() {
-                return cached.behavior_profile.app_data_record_sizes.clone();
-            }
+            return cached
+                .app_data_records_sizes
+                .first()
+                .copied()
+                .or_else(|| {
+                    cached
+                        .behavior_profile
+                        .app_data_record_sizes
+                        .first()
+                        .copied()
+                })
+                .map(|size| vec![size])
+                .unwrap_or_else(|| vec![cached.total_app_data_len.max(1024)]);
         }
         TlsProfileSource::Default | TlsProfileSource::Rustls => {}
     }
@@ -80,8 +90,8 @@ fn emulated_app_data_sizes(cached: &CachedTlsData) -> Vec<usize> {
     sizes
 }
 
-fn emulated_change_cipher_spec_count(cached: &CachedTlsData) -> usize {
-    usize::from(cached.behavior_profile.change_cipher_spec_count.max(1))
+fn emulated_change_cipher_spec_count(_cached: &CachedTlsData) -> usize {
+    1
 }
 
 fn emulated_ticket_record_sizes(
@@ -89,19 +99,20 @@ fn emulated_ticket_record_sizes(
     new_session_tickets: u8,
     rng: &SecureRandom,
 ) -> Vec<usize> {
-    let mut sizes = match cached.behavior_profile.source {
+    let target_count = usize::from(new_session_tickets.min(MAX_TICKET_RECORDS as u8));
+    if target_count == 0 {
+        return Vec::new();
+    }
+
+    let profiled_sizes = match cached.behavior_profile.source {
         TlsProfileSource::Raw | TlsProfileSource::Merged => {
-            cached.behavior_profile.ticket_record_sizes.clone()
+            cached.behavior_profile.ticket_record_sizes.as_slice()
         }
-        TlsProfileSource::Default | TlsProfileSource::Rustls => Vec::new(),
+        TlsProfileSource::Default | TlsProfileSource::Rustls => &[],
     };
 
-    let target_count = sizes
-        .len()
-        .max(usize::from(
-            new_session_tickets.min(MAX_TICKET_RECORDS as u8),
-        ))
-        .min(MAX_TICKET_RECORDS);
+    let mut sizes = Vec::with_capacity(target_count);
+    sizes.extend(profiled_sizes.iter().copied().take(target_count));
 
     while sizes.len() < target_count {
         sizes.push(rng.range(48) + 48);
@@ -242,7 +253,18 @@ pub fn build_emulated_server_hello(
     }
 
     // --- ApplicationData (fake encrypted records) ---
-    let mut sizes = jitter_and_clamp_sizes(&emulated_app_data_sizes(cached), rng);
+    let mut sizes = {
+        let base_sizes = emulated_app_data_sizes(cached);
+        match cached.behavior_profile.source {
+            TlsProfileSource::Raw | TlsProfileSource::Merged => base_sizes
+                .into_iter()
+                .map(|size| size.clamp(MIN_APP_DATA, MAX_APP_DATA))
+                .collect(),
+            TlsProfileSource::Default | TlsProfileSource::Rustls => {
+                jitter_and_clamp_sizes(&base_sizes, rng)
+            }
+        }
+    };
     let compact_payload = cached
         .cert_info
         .as_ref()
@@ -508,7 +530,7 @@ mod tests {
     }
 
     #[test]
-    fn test_build_emulated_server_hello_replays_tail_records_for_profiled_tls() {
+    fn test_build_emulated_server_hello_ignores_tail_records_for_profiled_tls() {
         let mut cached = make_cached(None);
         cached.app_data_records_sizes = vec![27, 3905, 537, 69];
         cached.total_app_data_len = 4538;
@@ -530,19 +552,11 @@ mod tests {
 
         let hello_len = u16::from_be_bytes([response[3], response[4]]) as usize;
         let ccs_start = 5 + hello_len;
-        let mut pos = ccs_start + 6;
-        let mut app_lengths = Vec::new();
-        while pos + 5 <= response.len() {
-            assert_eq!(response[pos], TLS_RECORD_APPLICATION);
-            let record_len = u16::from_be_bytes([response[pos + 3], response[pos + 4]]) as usize;
-            app_lengths.push(record_len);
-            pos += 5 + record_len;
-        }
-
-        assert_eq!(app_lengths.len(), 4);
-        assert_eq!(app_lengths[0], 64);
-        assert_eq!(app_lengths[3], 69);
-        assert!(app_lengths[1] >= 64);
-        assert!(app_lengths[2] >= 64);
+        let app_start = ccs_start + 6;
+        let app_len =
+            u16::from_be_bytes([response[app_start + 3], response[app_start + 4]]) as usize;
+        assert_eq!(response[app_start], TLS_RECORD_APPLICATION);
+        assert_eq!(app_len, 64);
+        assert_eq!(app_start + 5 + app_len, response.len());
     }
 }

src/tls_front/tests/emulator_profile_fidelity_security_tests.rs

@@ -52,7 +52,7 @@ fn record_lengths_by_type(response: &[u8], wanted_type: u8) -> Vec<usize> {
 }
 
 #[test]
-fn emulated_server_hello_replays_profile_change_cipher_spec_count() {
+fn emulated_server_hello_keeps_single_change_cipher_spec_for_client_compatibility() {
     let cached = make_cached();
     let rng = SecureRandom::new();
 
@@ -69,12 +69,12 @@ fn emulated_server_hello_replays_profile_change_cipher_spec_count() {
 
     assert_eq!(response[0], TLS_RECORD_HANDSHAKE);
     let ccs_records = record_lengths_by_type(&response, TLS_RECORD_CHANGE_CIPHER);
-    assert_eq!(ccs_records.len(), 2);
+    assert_eq!(ccs_records.len(), 1);
     assert!(ccs_records.iter().all(|len| *len == 1));
 }
 
 #[test]
-fn emulated_server_hello_replays_profile_ticket_tail_lengths() {
+fn emulated_server_hello_does_not_emit_profile_ticket_tail_when_disabled() {
     let cached = make_cached();
     let rng = SecureRandom::new();
 
@@ -90,6 +90,25 @@ fn emulated_server_hello_replays_profile_ticket_tail_lengths() {
     );
 
     let app_records = record_lengths_by_type(&response, TLS_RECORD_APPLICATION);
-    assert!(app_records.len() >= 4);
-    assert_eq!(&app_records[app_records.len() - 2..], &[220, 180]);
+    assert_eq!(app_records, vec![1200]);
+}
+
+#[test]
+fn emulated_server_hello_uses_profile_ticket_lengths_when_enabled() {
+    let cached = make_cached();
+    let rng = SecureRandom::new();
+
+    let response = build_emulated_server_hello(
+        b"secret",
+        &[0x91; 32],
+        &[0x92; 16],
+        &cached,
+        false,
+        &rng,
+        None,
+        2,
+    );
+
+    let app_records = record_lengths_by_type(&response, TLS_RECORD_APPLICATION);
+    assert_eq!(app_records, vec![1200, 220, 180]);
 }

src/transport/upstream.rs

@@ -279,6 +279,12 @@ pub struct UpstreamApiSummarySnapshot {
     pub shadowsocks_total: usize,
 }
 
+#[derive(Debug, Clone, Copy, Default)]
+pub struct UpstreamApiHealthSummary {
+    pub configured_total: usize,
+    pub healthy_total: usize,
+}
+
 #[derive(Debug, Clone)]
 pub struct UpstreamApiSnapshot {
     pub summary: UpstreamApiSummarySnapshot,
@@ -444,6 +450,20 @@ impl UpstreamManager {
         Some(UpstreamApiSnapshot { summary, upstreams })
     }
 
+    pub async fn api_health_summary(&self) -> UpstreamApiHealthSummary {
+        let guard = self.upstreams.read().await;
+        let mut summary = UpstreamApiHealthSummary {
+            configured_total: guard.len(),
+            healthy_total: 0,
+        };
+        for upstream in guard.iter() {
+            if upstream.healthy {
+                summary.healthy_total += 1;
+            }
+        }
+        summary
+    }
+
     fn describe_upstream(upstream_type: &UpstreamType) -> (UpstreamRouteKind, String) {
         match upstream_type {
             UpstreamType::Direct { .. } => (UpstreamRouteKind::Direct, "direct".to_string()),