Cleanup Methods for Memory Consistency

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>

src/ip_tracker.rs

@@ -26,6 +26,15 @@ pub struct UserIpTracker {
     cleanup_drain_lock: Arc<AsyncMutex<()>>,
 }
 
+#[derive(Debug, Clone, Copy)]
+pub struct UserIpTrackerMemoryStats {
+    pub active_users: usize,
+    pub recent_users: usize,
+    pub active_entries: usize,
+    pub recent_entries: usize,
+    pub cleanup_queue_len: usize,
+}
+
 impl UserIpTracker {
     pub fn new() -> Self {
         Self {
@@ -141,6 +150,13 @@ impl UserIpTracker {
 
         let mut active_ips = self.active_ips.write().await;
         let mut recent_ips = self.recent_ips.write().await;
+        let window = *self.limit_window.read().await;
+        let now = Instant::now();
+
+        for user_recent in recent_ips.values_mut() {
+            Self::prune_recent(user_recent, now, window);
+        }
+
         let mut users =
             Vec::<String>::with_capacity(active_ips.len().saturating_add(recent_ips.len()));
         users.extend(active_ips.keys().cloned());
@@ -166,6 +182,26 @@ impl UserIpTracker {
         }
     }
 
+    pub async fn memory_stats(&self) -> UserIpTrackerMemoryStats {
+        let cleanup_queue_len = self
+            .cleanup_queue
+            .lock()
+            .unwrap_or_else(|poisoned| poisoned.into_inner())
+            .len();
+        let active_ips = self.active_ips.read().await;
+        let recent_ips = self.recent_ips.read().await;
+        let active_entries = active_ips.values().map(HashMap::len).sum();
+        let recent_entries = recent_ips.values().map(HashMap::len).sum();
+
+        UserIpTrackerMemoryStats {
+            active_users: active_ips.len(),
+            recent_users: recent_ips.len(),
+            active_entries,
+            recent_entries,
+            cleanup_queue_len,
+        }
+    }
+
     pub async fn set_limit_policy(&self, mode: UserMaxUniqueIpsMode, window_secs: u64) {
         {
             let mut current_mode = self.limit_mode.write().await;
@@ -451,6 +487,7 @@ impl Default for UserIpTracker {
 mod tests {
     use super::*;
     use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
+    use std::sync::atomic::Ordering;
 
     fn test_ipv4(oct1: u8, oct2: u8, oct3: u8, oct4: u8) -> IpAddr {
         IpAddr::V4(Ipv4Addr::new(oct1, oct2, oct3, oct4))
@@ -764,4 +801,54 @@ mod tests {
         tokio::time::sleep(Duration::from_millis(1100)).await;
         assert!(tracker.check_and_add("test_user", ip2).await.is_ok());
     }
+
+    #[tokio::test]
+    async fn test_memory_stats_reports_queue_and_entry_counts() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 4).await;
+        let ip1 = test_ipv4(10, 2, 0, 1);
+        let ip2 = test_ipv4(10, 2, 0, 2);
+
+        tracker.check_and_add("test_user", ip1).await.unwrap();
+        tracker.check_and_add("test_user", ip2).await.unwrap();
+        tracker.enqueue_cleanup("test_user".to_string(), ip1);
+
+        let snapshot = tracker.memory_stats().await;
+        assert_eq!(snapshot.active_users, 1);
+        assert_eq!(snapshot.recent_users, 1);
+        assert_eq!(snapshot.active_entries, 2);
+        assert_eq!(snapshot.recent_entries, 2);
+        assert_eq!(snapshot.cleanup_queue_len, 1);
+    }
+
+    #[tokio::test]
+    async fn test_compact_prunes_stale_recent_entries() {
+        let tracker = UserIpTracker::new();
+        tracker
+            .set_limit_policy(UserMaxUniqueIpsMode::TimeWindow, 1)
+            .await;
+
+        let stale_user = "stale-user".to_string();
+        let stale_ip = test_ipv4(10, 3, 0, 1);
+        {
+            let mut recent_ips = tracker.recent_ips.write().await;
+            recent_ips
+                .entry(stale_user.clone())
+                .or_insert_with(HashMap::new)
+                .insert(stale_ip, Instant::now() - Duration::from_secs(5));
+        }
+
+        tracker.last_compact_epoch_secs.store(0, Ordering::Relaxed);
+        tracker
+            .check_and_add("trigger-user", test_ipv4(10, 3, 0, 2))
+            .await
+            .unwrap();
+
+        let recent_ips = tracker.recent_ips.read().await;
+        let stale_exists = recent_ips
+            .get(&stale_user)
+            .map(|ips| ips.contains_key(&stale_ip))
+            .unwrap_or(false);
+        assert!(!stale_exists);
+    }
 }

src/metrics.rs

@@ -2490,6 +2490,48 @@ async fn render_metrics(stats: &Stats, config: &ProxyConfig, ip_tracker: &UserIp
         if user_enabled { 0 } else { 1 }
     );
 
+    let ip_memory = ip_tracker.memory_stats().await;
+    let _ = writeln!(
+        out,
+        "# HELP telemt_ip_tracker_users Number of users tracked by IP limiter state"
+    );
+    let _ = writeln!(out, "# TYPE telemt_ip_tracker_users gauge");
+    let _ = writeln!(
+        out,
+        "telemt_ip_tracker_users{{scope=\"active\"}} {}",
+        ip_memory.active_users
+    );
+    let _ = writeln!(
+        out,
+        "telemt_ip_tracker_users{{scope=\"recent\"}} {}",
+        ip_memory.recent_users
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_ip_tracker_entries Number of IP entries tracked by limiter state"
+    );
+    let _ = writeln!(out, "# TYPE telemt_ip_tracker_entries gauge");
+    let _ = writeln!(
+        out,
+        "telemt_ip_tracker_entries{{scope=\"active\"}} {}",
+        ip_memory.active_entries
+    );
+    let _ = writeln!(
+        out,
+        "telemt_ip_tracker_entries{{scope=\"recent\"}} {}",
+        ip_memory.recent_entries
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_ip_tracker_cleanup_queue_len Deferred disconnect cleanup queue length"
+    );
+    let _ = writeln!(out, "# TYPE telemt_ip_tracker_cleanup_queue_len gauge");
+    let _ = writeln!(
+        out,
+        "telemt_ip_tracker_cleanup_queue_len {}",
+        ip_memory.cleanup_queue_len
+    );
+
     if user_enabled {
         for entry in stats.iter_user_stats() {
             let user = entry.key();
@@ -2728,6 +2770,9 @@ mod tests {
         assert!(output.contains("telemt_user_unique_ips_recent_window{user=\"alice\"} 1"));
         assert!(output.contains("telemt_user_unique_ips_limit{user=\"alice\"} 4"));
         assert!(output.contains("telemt_user_unique_ips_utilization{user=\"alice\"} 0.250000"));
+        assert!(output.contains("telemt_ip_tracker_users{scope=\"active\"} 1"));
+        assert!(output.contains("telemt_ip_tracker_entries{scope=\"active\"} 1"));
+        assert!(output.contains("telemt_ip_tracker_cleanup_queue_len 0"));
     }
 
     #[tokio::test]
@@ -2799,6 +2844,9 @@ mod tests {
         assert!(output.contains("# TYPE telemt_user_unique_ips_recent_window gauge"));
         assert!(output.contains("# TYPE telemt_user_unique_ips_limit gauge"));
         assert!(output.contains("# TYPE telemt_user_unique_ips_utilization gauge"));
+        assert!(output.contains("# TYPE telemt_ip_tracker_users gauge"));
+        assert!(output.contains("# TYPE telemt_ip_tracker_entries gauge"));
+        assert!(output.contains("# TYPE telemt_ip_tracker_cleanup_queue_len gauge"));
     }
 
     #[tokio::test]

src/stats/mod.rs

@@ -2171,6 +2171,8 @@ impl ReplayShard {
 
     fn cleanup(&mut self, now: Instant, window: Duration) {
         if window.is_zero() {
+            self.cache.clear();
+            self.queue.clear();
             return;
         }
         let cutoff = now.checked_sub(window).unwrap_or(now);
@@ -2192,13 +2194,22 @@ impl ReplayShard {
     }
 
     fn check(&mut self, key: &[u8], now: Instant, window: Duration) -> bool {
+        if window.is_zero() {
+            return false;
+        }
         self.cleanup(now, window);
         // key is &[u8], resolves Q=[u8] via Box<[u8]>: Borrow<[u8]>
         self.cache.get(key).is_some()
     }
 
     fn add(&mut self, key: &[u8], now: Instant, window: Duration) {
+        if window.is_zero() {
+            return;
+        }
         self.cleanup(now, window);
+        if self.cache.peek(key).is_some() {
+            return;
+        }
 
         let seq = self.next_seq();
         let boxed_key: Box<[u8]> = key.into();
@@ -2341,7 +2352,7 @@ impl ReplayChecker {
         let interval = if self.window.as_secs() > 60 {
             Duration::from_secs(30)
         } else {
-            Duration::from_secs(self.window.as_secs().max(1) / 2)
+            Duration::from_secs((self.window.as_secs().max(1) / 2).max(1))
         };
 
         loop {
@@ -2553,6 +2564,20 @@ mod tests {
         assert!(!checker.check_handshake(b"expire"));
     }
 
+    #[test]
+    fn test_replay_checker_zero_window_does_not_retain_entries() {
+        let checker = ReplayChecker::new(100, Duration::ZERO);
+
+        for _ in 0..1_000 {
+            assert!(!checker.check_handshake(b"no-retain"));
+            checker.add_handshake(b"no-retain");
+        }
+
+        let stats = checker.stats();
+        assert_eq!(stats.total_entries, 0);
+        assert_eq!(stats.total_queue_len, 0);
+    }
+
     #[test]
     fn test_replay_checker_stats() {
         let checker = ReplayChecker::new(100, Duration::from_secs(60));

src/stream/buffer_pool.rs

@@ -35,6 +35,10 @@ pub struct BufferPool {
     misses: AtomicUsize,
     /// Number of successful reuses
     hits: AtomicUsize,
+    /// Number of non-standard buffers replaced with a fresh default-sized buffer
+    replaced_nonstandard: AtomicUsize,
+    /// Number of buffers dropped because the pool queue was full
+    dropped_pool_full: AtomicUsize,
 }
 
 impl BufferPool {
@@ -52,6 +56,8 @@ impl BufferPool {
             allocated: AtomicUsize::new(0),
             misses: AtomicUsize::new(0),
             hits: AtomicUsize::new(0),
+            replaced_nonstandard: AtomicUsize::new(0),
+            dropped_pool_full: AtomicUsize::new(0),
         }
     }
 
@@ -91,17 +97,36 @@ impl BufferPool {
 
     /// Return a buffer to the pool
     fn return_buffer(&self, mut buffer: BytesMut) {
-        // Clear the buffer but keep capacity
-        buffer.clear();
+        const MAX_RETAINED_BUFFER_FACTOR: usize = 2;
 
-        // Only return if we haven't exceeded max and buffer is right size
-        if buffer.capacity() >= self.buffer_size {
-            // Try to push to pool, if full just drop
-            let _ = self.buffers.push(buffer);
+        // Clear the buffer but keep capacity.
+        buffer.clear();
+        let max_retained_capacity = self
+            .buffer_size
+            .saturating_mul(MAX_RETAINED_BUFFER_FACTOR)
+            .max(self.buffer_size);
+
+        // Keep only near-default capacities in the pool. Oversized buffers keep
+        // RSS elevated for hours under churn; replace them with default-sized
+        // buffers before re-pooling.
+        if buffer.capacity() < self.buffer_size || buffer.capacity() > max_retained_capacity {
+            self.replaced_nonstandard.fetch_add(1, Ordering::Relaxed);
+            buffer = BytesMut::with_capacity(self.buffer_size);
         }
-        // If buffer was dropped (pool full), decrement allocated
-        // Actually we don't decrement here because the buffer might have been
-        // grown beyond our size - we just let it go
+
+        // Try to return into the queue; if full, drop and update accounting.
+        if self.buffers.push(buffer).is_err() {
+            self.dropped_pool_full.fetch_add(1, Ordering::Relaxed);
+            self.decrement_allocated();
+        }
+    }
+
+    fn decrement_allocated(&self) {
+        let _ = self
+            .allocated
+            .fetch_update(Ordering::Relaxed, Ordering::Relaxed, |current| {
+                Some(current.saturating_sub(1))
+            });
     }
 
     /// Get pool statistics
@@ -113,6 +138,8 @@ impl BufferPool {
             buffer_size: self.buffer_size,
             hits: self.hits.load(Ordering::Relaxed),
             misses: self.misses.load(Ordering::Relaxed),
+            replaced_nonstandard: self.replaced_nonstandard.load(Ordering::Relaxed),
+            dropped_pool_full: self.dropped_pool_full.load(Ordering::Relaxed),
         }
     }
 
@@ -160,6 +187,10 @@ pub struct PoolStats {
     pub hits: usize,
     /// Number of cache misses (new allocation)
     pub misses: usize,
+    /// Number of non-standard buffers replaced during return
+    pub replaced_nonstandard: usize,
+    /// Number of buffers dropped because the pool queue was full
+    pub dropped_pool_full: usize,
 }
 
 impl PoolStats {
@@ -185,6 +216,7 @@ pub struct PooledBuffer {
 impl PooledBuffer {
     /// Take the inner buffer, preventing return to pool
     pub fn take(mut self) -> BytesMut {
+        self.pool.decrement_allocated();
         self.buffer.take().unwrap()
     }
 
@@ -364,6 +396,25 @@ mod tests {
 
         let stats = pool.stats();
         assert_eq!(stats.pooled, 0);
+        assert_eq!(stats.allocated, 0);
+    }
+
+    #[test]
+    fn test_pool_replaces_oversized_buffers() {
+        let pool = Arc::new(BufferPool::with_config(1024, 10));
+
+        {
+            let mut buf = pool.get();
+            buf.reserve(8192);
+            assert!(buf.capacity() > 2048);
+        }
+
+        let stats = pool.stats();
+        assert_eq!(stats.replaced_nonstandard, 1);
+        assert_eq!(stats.pooled, 1);
+
+        let buf = pool.get();
+        assert!(buf.capacity() <= 2048);
     }
 
     #[test]