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WritersState on ArcSwao + Preferred Endpoint on ArcSwap + Two-map Rotation for Desync Dedup 

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>
This commit is contained in:
Alexey 2026-03-25 17:25:35 +03:00
parent 41d786cc11
commit 8bab3f70e1
No known key found for this signature in database
5 changed files with 182 additions and 69 deletions
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143
src/proxy/middle_relay.rs
View File

@ -4,7 +4,7 @@ use std::collections::{BTreeSet, HashMap};
use std::future::Future;
use std::hash::{BuildHasher, Hash};
use std::net::{IpAddr, SocketAddr};
use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
use std::sync::atomic::{AtomicU64, Ordering};
use std::sync::{Arc, Mutex, OnceLock};
use std::time::{Duration, Instant};
@ -36,7 +36,6 @@ enum C2MeCommand {
const DESYNC_DEDUP_WINDOW: Duration = Duration::from_secs(60);
const DESYNC_DEDUP_MAX_ENTRIES: usize = 65_536;
const DESYNC_DEDUP_PRUNE_SCAN_LIMIT: usize = 1024;
const DESYNC_FULL_CACHE_EMIT_MIN_INTERVAL: Duration = Duration::from_millis(1000);
const DESYNC_ERROR_CLASS: &str = "frame_too_large_crypto_desync";
const C2ME_CHANNEL_CAPACITY_FALLBACK: usize = 128;
@ -57,12 +56,18 @@ const ME_D2C_FRAME_BUF_SHRINK_HYSTERESIS_FACTOR: usize = 2;
const ME_D2C_SINGLE_WRITE_COALESCE_MAX_BYTES: usize = 128 * 1024;
const QUOTA_RESERVE_SPIN_RETRIES: usize = 32;
static DESYNC_DEDUP: OnceLock<DashMap<u64, Instant>> = OnceLock::new();
static DESYNC_DEDUP_PREVIOUS: OnceLock<DashMap<u64, Instant>> = OnceLock::new();
static DESYNC_HASHER: OnceLock<RandomState> = OnceLock::new();
static DESYNC_FULL_CACHE_LAST_EMIT_AT: OnceLock<Mutex<Option<Instant>>> = OnceLock::new();
static DESYNC_DEDUP_EVER_SATURATED: OnceLock<AtomicBool> = OnceLock::new();
static DESYNC_DEDUP_ROTATION_STATE: OnceLock<Mutex<DesyncDedupRotationState>> = OnceLock::new();
static RELAY_IDLE_CANDIDATE_REGISTRY: OnceLock<Mutex<RelayIdleCandidateRegistry>> = OnceLock::new();
static RELAY_IDLE_MARK_SEQ: AtomicU64 = AtomicU64::new(0);
#[derive(Default)]
struct DesyncDedupRotationState {
current_started_at: Option<Instant>,
}
struct RelayForensicsState {
trace_id: u64,
conn_id: u64,
@ -312,64 +317,76 @@ fn should_emit_full_desync(key: u64, all_full: bool, now: Instant) -> bool {
return true;
}
let dedup = DESYNC_DEDUP.get_or_init(DashMap::new);
let saturated_before = dedup.len() >= DESYNC_DEDUP_MAX_ENTRIES;
let ever_saturated = DESYNC_DEDUP_EVER_SATURATED.get_or_init(|| AtomicBool::new(false));
if saturated_before {
ever_saturated.store(true, Ordering::Relaxed);
}
let dedup_current = DESYNC_DEDUP.get_or_init(DashMap::new);
let dedup_previous = DESYNC_DEDUP_PREVIOUS.get_or_init(DashMap::new);
let rotation_state = DESYNC_DEDUP_ROTATION_STATE
.get_or_init(|| Mutex::new(DesyncDedupRotationState::default()));
if let Some(mut seen_at) = dedup.get_mut(&key) {
if now.duration_since(*seen_at) >= DESYNC_DEDUP_WINDOW {
*seen_at = now;
return true;
let mut state = match rotation_state.lock() {
Ok(guard) => guard,
Err(poisoned) => {
let mut guard = poisoned.into_inner();
*guard = DesyncDedupRotationState::default();
rotation_state.clear_poison();
guard
}
return false;
}
if dedup.len() >= DESYNC_DEDUP_MAX_ENTRIES {
let mut stale_keys = Vec::new();
let mut oldest_candidate: Option<(u64, Instant)> = None;
for entry in dedup.iter().take(DESYNC_DEDUP_PRUNE_SCAN_LIMIT) {
let key = *entry.key();
let seen_at = *entry.value();
match oldest_candidate {
Some((_, oldest_seen)) if seen_at >= oldest_seen => {}
_ => oldest_candidate = Some((key, seen_at)),
}
if now.duration_since(seen_at) >= DESYNC_DEDUP_WINDOW {
stale_keys.push(*entry.key());
}
}
for stale_key in stale_keys {
dedup.remove(&stale_key);
}
if dedup.len() >= DESYNC_DEDUP_MAX_ENTRIES {
let Some((evict_key, _)) = oldest_candidate else {
return false;
};
dedup.remove(&evict_key);
dedup.insert(key, now);
return should_emit_full_desync_full_cache(now);
}
}
dedup.insert(key, now);
let saturated_after = dedup.len() >= DESYNC_DEDUP_MAX_ENTRIES;
// Preserve the first sequential insert that reaches capacity as a normal
// emit, while still gating concurrent newcomer churn after the cache has
// ever been observed at saturation.
let was_ever_saturated = if saturated_after {
ever_saturated.swap(true, Ordering::Relaxed)
} else {
ever_saturated.load(Ordering::Relaxed)
};
if saturated_before || (saturated_after && was_ever_saturated) {
let rotate_now = match state.current_started_at {
Some(current_started_at) => match now.checked_duration_since(current_started_at) {
Some(elapsed) => elapsed >= DESYNC_DEDUP_WINDOW,
None => true,
},
None => true,
};
if rotate_now {
dedup_previous.clear();
for entry in dedup_current.iter() {
dedup_previous.insert(*entry.key(), *entry.value());
}
dedup_current.clear();
state.current_started_at = Some(now);
}
if let Some(seen_at) = dedup_current.get(&key).map(|entry| *entry.value()) {
let within_window = match now.checked_duration_since(seen_at) {
Some(elapsed) => elapsed < DESYNC_DEDUP_WINDOW,
None => true,
};
if within_window {
return false;
}
dedup_current.insert(key, now);
return true;
}
if let Some(seen_at) = dedup_previous.get(&key).map(|entry| *entry.value()) {
let within_window = match now.checked_duration_since(seen_at) {
Some(elapsed) => elapsed < DESYNC_DEDUP_WINDOW,
None => true,
};
if within_window {
// Keep the original timestamp when promoting from previous bucket,
// so dedup expiry remains tied to first-seen time.
dedup_current.insert(key, seen_at);
return false;
}
dedup_previous.remove(&key);
}
if dedup_current.len() >= DESYNC_DEDUP_MAX_ENTRIES {
// Bounded eviction path: rotate buckets instead of scanning/evicting
// arbitrary entries from a saturated single map.
dedup_previous.clear();
for entry in dedup_current.iter() {
dedup_previous.insert(*entry.key(), *entry.value());
}
dedup_current.clear();
state.current_started_at = Some(now);
dedup_current.insert(key, now);
should_emit_full_desync_full_cache(now)
} else {
dedup_current.insert(key, now);
true
}
}
@ -405,8 +422,20 @@ fn clear_desync_dedup_for_testing() {
if let Some(dedup) = DESYNC_DEDUP.get() {
dedup.clear();
}
if let Some(ever_saturated) = DESYNC_DEDUP_EVER_SATURATED.get() {
ever_saturated.store(false, Ordering::Relaxed);
if let Some(dedup_previous) = DESYNC_DEDUP_PREVIOUS.get() {
dedup_previous.clear();
}
if let Some(rotation_state) = DESYNC_DEDUP_ROTATION_STATE.get() {
match rotation_state.lock() {
Ok(mut guard) => {
*guard = DesyncDedupRotationState::default();
}
Err(poisoned) => {
let mut guard = poisoned.into_inner();
*guard = DesyncDedupRotationState::default();
rotation_state.clear_poison();
}
}
}
if let Some(last_emit_at) = DESYNC_FULL_CACHE_LAST_EMIT_AT.get() {
match last_emit_at.lock() {

96
src/transport/middle_proxy/pool.rs
View File

@ -2,6 +2,7 @@
use std::collections::{HashMap, HashSet};
use std::net::{IpAddr, Ipv6Addr, SocketAddr};
use std::ops::{Deref, DerefMut};
use std::sync::Arc;
use std::sync::atomic::{
AtomicBool, AtomicI32, AtomicU8, AtomicU32, AtomicU64, AtomicUsize, Ordering,
@ -56,6 +57,87 @@ pub struct MeWriter {
pub allow_drain_fallback: Arc<AtomicBool>,
}
pub(super) struct WritersState {
// HARD INVARIANT:
// All writers.store() calls MUST be guarded by writers_write_guard.
writers: ArcSwap<Vec<MeWriter>>,
writers_write_guard: Mutex<()>,
}
impl WritersState {
pub(super) fn new() -> Self {
Self {
writers: ArcSwap::from_pointee(Vec::new()),
writers_write_guard: Mutex::new(()),
}
}
pub(super) fn snapshot(&self) -> Arc<Vec<MeWriter>> {
self.writers.load_full()
}
pub(super) async fn read(&self) -> Arc<Vec<MeWriter>> {
self.snapshot()
}
pub(super) async fn write(&self) -> WritersWriteGuard<'_> {
let guard = self.writers_write_guard.lock().await;
let writers = (*self.writers.load_full()).clone();
WritersWriteGuard {
state: self,
_guard: guard,
writers,
}
}
pub(super) async fn update<F, R>(&self, f: F) -> R
where
F: FnOnce(&mut Vec<MeWriter>) -> R,
{
let mut guard = self.write().await;
f(&mut guard)
}
fn debug_assert_store_guarded(&self) {
debug_assert!(
self.writers_write_guard.try_lock().is_err(),
"HARD INVARIANT violated: writers.store() without writers_write_guard"
);
}
fn store_guarded(&self, writers: Vec<MeWriter>) {
self.debug_assert_store_guarded();
self.writers.store(Arc::new(writers));
}
}
pub(super) struct WritersWriteGuard<'a> {
state: &'a WritersState,
_guard: tokio::sync::MutexGuard<'a, ()>,
writers: Vec<MeWriter>,
}
impl Deref for WritersWriteGuard<'_> {
type Target = Vec<MeWriter>;
fn deref(&self) -> &Self::Target {
&self.writers
}
}
impl DerefMut for WritersWriteGuard<'_> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.writers
}
}
impl Drop for WritersWriteGuard<'_> {
fn drop(&mut self) {
let writers = std::mem::take(&mut self.writers);
self.state.store_guarded(writers);
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(u8)]
pub(super) enum WriterContour {
@ -178,7 +260,7 @@ pub struct SecretSnapshot {
#[allow(dead_code)]
pub struct MePool {
pub(super) registry: Arc<ConnRegistry>,
pub(super) writers: Arc<RwLock<Vec<MeWriter>>>,
pub(super) writers: Arc<WritersState>,
pub(super) rr: AtomicU64,
pub(super) decision: NetworkDecision,
pub(super) upstream: Option<Arc<UpstreamManager>>,
@ -307,7 +389,7 @@ pub struct MePool {
pub(super) me_last_drain_gate_updated_at_epoch_secs: AtomicU64,
pub(super) runtime_ready: AtomicBool,
pool_size: usize,
pub(super) preferred_endpoints_by_dc: Arc<RwLock<HashMap<i32, Vec<SocketAddr>>>>,
pub(super) preferred_endpoints_by_dc: ArcSwap<HashMap<i32, Vec<SocketAddr>>>,
}
#[derive(Debug, Default)]
@ -443,7 +525,7 @@ impl MePool {
let now_epoch_secs = Self::now_epoch_secs();
Arc::new(Self {
registry,
writers: Arc::new(RwLock::new(Vec::new())),
writers: Arc::new(WritersState::new()),
rr: AtomicU64::new(0),
decision,
upstream,
@ -649,7 +731,7 @@ impl MePool {
me_last_drain_gate_block_reason: AtomicU8::new(MeDrainGateReason::Open as u8),
me_last_drain_gate_updated_at_epoch_secs: AtomicU64::new(now_epoch_secs),
runtime_ready: AtomicBool::new(false),
preferred_endpoints_by_dc: Arc::new(RwLock::new(preferred_endpoints_by_dc)),
preferred_endpoints_by_dc: ArcSwap::from_pointee(preferred_endpoints_by_dc),
})
}
@ -1004,7 +1086,7 @@ impl MePool {
MeSocksKdfPolicy::from_u8(self.me_socks_kdf_policy.load(Ordering::Relaxed))
}
pub(super) fn writers_arc(&self) -> Arc<RwLock<Vec<MeWriter>>> {
pub(super) fn writers_arc(&self) -> Arc<WritersState> {
self.writers.clone()
}
@ -1602,7 +1684,7 @@ impl MePool {
let rebuilt = Self::build_endpoint_dc_map_from_maps(&map_v4, &map_v6);
let preferred = Self::build_preferred_endpoints_by_dc(&self.decision, &map_v4, &map_v6);
*self.endpoint_dc_map.write().await = rebuilt;
*self.preferred_endpoints_by_dc.write().await = preferred;
self.preferred_endpoints_by_dc.store(Arc::new(preferred));
let configured_endpoints = self
.endpoint_dc_map
.read()
@ -1622,7 +1704,7 @@ impl MePool {
}
pub(super) async fn preferred_endpoints_for_dc(&self, dc: i32) -> Vec<SocketAddr> {
let guard = self.preferred_endpoints_by_dc.read().await;
let guard = self.preferred_endpoints_by_dc.load();
guard.get(&dc).cloned().unwrap_or_default()
}

2
src/transport/middle_proxy/pool_config.rs
View File

@ -112,7 +112,7 @@ impl MePool {
pub async fn reconnect_all(self: &Arc<Self>) {
let ws = self.writers.read().await.clone();
for w in ws {
for w in ws.iter() {
if let Ok(()) = self
.connect_one_for_dc(w.addr, w.writer_dc, self.rng.as_ref())
.await

6
src/transport/middle_proxy/pool_status.rs
View File

@ -160,7 +160,7 @@ impl MePool {
let writers = self.writers.read().await.clone();
let mut live_writers_by_dc = HashMap::<i16, usize>::new();
for writer in writers {
for writer in writers.iter() {
if writer.draining.load(Ordering::Relaxed) {
continue;
}
@ -197,7 +197,7 @@ impl MePool {
let writers = self.writers.read().await.clone();
let mut live_writers_by_dc = HashMap::<i16, usize>::new();
for writer in writers {
for writer in writers.iter() {
if writer.draining.load(Ordering::Relaxed) {
continue;
}
@ -255,7 +255,7 @@ impl MePool {
let mut dc_rtt_agg = HashMap::<i16, (f64, u64)>::new();
let mut writer_rows = Vec::<MeApiWriterStatusSnapshot>::with_capacity(writers.len());
for writer in writers {
for writer in writers.iter() {
let endpoint = writer.addr;
let dc = i16::try_from(writer.writer_dc).ok();
let draining = writer.draining.load(Ordering::Relaxed);

4
src/transport/middle_proxy/pool_writer.rs
View File

@ -195,7 +195,9 @@ impl MePool {
drain_deadline_epoch_secs: drain_deadline_epoch_secs.clone(),
allow_drain_fallback: allow_drain_fallback.clone(),
};
self.writers.write().await.push(writer.clone());
self.writers
.update(|writers| writers.push(writer.clone()))
.await;
self.registry.register_writer(writer_id, tx.clone()).await;
self.registry.mark_writer_idle(writer_id).await;
self.conn_count.fetch_add(1, Ordering::Relaxed);