v4.5.10

changelog.md

@@ -1,5 +1,64 @@
 # Changelog
 
+## 2026-03-16 - 4.5.10 - fix(remoteingress-core)
+guard zero-window reads to avoid false EOF handling on stalled streams
+
+- Prevent upload and download loops from calling read on an empty buffer when flow-control window remains at 0 after stall timeout
+- Log a warning and close the affected stream instead of misinterpreting Ok(0) as end-of-file
+
+## 2026-03-16 - 4.5.9 - fix(remoteingress-core)
+delay stream close until downstream response draining finishes to prevent truncated transfers
+
+- Waits for the hub-to-client download task to finish before sending the stream CLOSE frame
+- Prevents upstream reads from being cancelled mid-response during asymmetric transfers such as git fetch
+- Retains the existing timeout so stalled downloads still clean up safely
+
+## 2026-03-16 - 4.5.8 - fix(remoteingress-core)
+ensure upstream writes cancel promptly and reliably deliver CLOSE_BACK frames
+
+- listen for stream cancellation while waiting on upstream write timeouts so FRAME_CLOSE does not block for up to 60 seconds
+- replace try_send with send().await when emitting CLOSE_BACK frames to avoid silently dropping close notifications when the data channel is full
+
+## 2026-03-16 - 4.5.7 - fix(remoteingress-core)
+improve tunnel reconnect and frame write efficiency
+
+- Reuse the TLS connector across edge reconnections to preserve session resumption state and reduce reconnect latency.
+- Buffer hub and edge frame writes to coalesce small control and data frames into fewer TLS records and syscalls while still flushing each frame promptly.
+
+## 2026-03-16 - 4.5.6 - fix(remoteingress-core)
+disable Nagle's algorithm on edge, hub, and upstream TCP sockets to reduce control-frame latency
+
+- Enable TCP_NODELAY on the edge connection to the hub for faster PING/PONG and WINDOW_UPDATE delivery
+- Apply TCP_NODELAY on accepted hub streams before TLS handling
+- Enable TCP_NODELAY on SmartProxy upstream connections before sending the PROXY header
+
+## 2026-03-16 - 4.5.5 - fix(remoteingress-core)
+wait for hub-to-client draining before cleanup and reliably send close frames
+
+- switch CLOSE frame delivery on the data channel from try_send to send().await to avoid dropping it when the channel is full
+- delay stream cleanup until the hub-to-client task finishes or times out so large downstream responses continue after upload EOF
+- add a bounded 5-minute wait for download draining to prevent premature termination of asymmetric transfers such as git fetch
+
+## 2026-03-15 - 4.5.4 - fix(remoteingress-core)
+preserve stream close ordering and add flow-control stall timeouts
+
+- Send CLOSE and CLOSE_BACK frames on the data channel so they arrive after the final stream data frames.
+- Log and abort stalled upload and download paths when flow-control windows stay empty for 120 seconds.
+- Apply a 60-second timeout when writing buffered stream data to the upstream connection to prevent hung streams.
+
+## 2026-03-15 - 4.5.3 - fix(remoteingress-core)
+prioritize control frames over data in edge and hub tunnel writers
+
+- Split tunnel/frame writers into separate control and data channels in edge and hub
+- Use biased select loops so PING, PONG, WINDOW_UPDATE, OPEN, and CLOSE frames are sent before data frames
+- Route stream data through dedicated data channels while keeping OPEN, CLOSE, and flow-control updates on control channels to prevent keepalive starvation under load
+
+## 2026-03-15 - 4.5.2 - fix(remoteingress-core)
+improve stream flow control retries and increase channel buffer capacity
+
+- increase per-stream mpsc channel capacity from 128 to 256 on both edge and hub paths
+- only reset accumulated window update bytes after a successful try_send to avoid dropping flow-control credits when the update channel is busy
+
 ## 2026-03-15 - 4.5.1 - fix(protocol)
 increase per-stream flow control window and channel buffers to improve high-RTT throughput
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@serve.zone/remoteingress",
-  "version": "4.5.1",
+  "version": "4.5.10",
   "private": false,
   "description": "Edge ingress tunnel for DcRouter - accepts incoming TCP connections at network edge and tunnels them to DcRouter SmartProxy preserving client IP via PROXY protocol v1.",
   "main": "dist_ts/index.js",

rust/crates/remoteingress-core/src/edge.rs

@@ -194,6 +194,14 @@ async fn edge_main_loop(
     let mut backoff_ms: u64 = 1000;
     let max_backoff_ms: u64 = 30000;
 
+    // Build TLS config ONCE outside the reconnect loop — preserves session
+    // cache across reconnections for TLS session resumption (saves 1 RTT).
+    let tls_config = rustls::ClientConfig::builder()
+        .dangerous()
+        .with_custom_certificate_verifier(Arc::new(NoCertVerifier))
+        .with_no_client_auth();
+    let connector = TlsConnector::from(Arc::new(tls_config));
+
     loop {
         // Create a per-connection child token
         let connection_token = cancel_token.child_token();
@@ -209,6 +217,7 @@ async fn edge_main_loop(
             &listen_ports,
             &mut shutdown_rx,
             &connection_token,
+            &connector,
         )
         .await;
 
@@ -259,18 +268,16 @@ async fn connect_to_hub_and_run(
     listen_ports: &Arc<RwLock<Vec<u16>>>,
     shutdown_rx: &mut mpsc::Receiver<()>,
     connection_token: &CancellationToken,
+    connector: &TlsConnector,
 ) -> EdgeLoopResult {
-    // Build TLS connector that skips cert verification (auth is via secret)
-    let tls_config = rustls::ClientConfig::builder()
-        .dangerous()
-        .with_custom_certificate_verifier(Arc::new(NoCertVerifier))
-        .with_no_client_auth();
-
-    let connector = TlsConnector::from(Arc::new(tls_config));
 
     let addr = format!("{}:{}", config.hub_host, config.hub_port);
     let tcp = match TcpStream::connect(&addr).await {
-        Ok(s) => s,
+        Ok(s) => {
+            // Disable Nagle's algorithm for low-latency control frames (PING/PONG, WINDOW_UPDATE)
+            let _ = s.set_nodelay(true);
+            s
+        }
         Err(e) => {
             log::error!("Failed to connect to hub at {}: {}", addr, e);
             return EdgeLoopResult::Reconnect;
@@ -366,18 +373,34 @@ async fn connect_to_hub_and_run(
     let client_writers: Arc<Mutex<HashMap<u32, EdgeStreamState>>> =
         Arc::new(Mutex::new(HashMap::new()));
 
-    // A5: Channel-based tunnel writer replaces Arc<Mutex<WriteHalf>>
-    let (tunnel_writer_tx, mut tunnel_writer_rx) = mpsc::channel::<Vec<u8>>(4096);
+    // QoS dual-channel tunnel writer: control frames (PONG/WINDOW_UPDATE/CLOSE/OPEN)
+    // have priority over data frames (DATA). Prevents PING starvation under load.
+    let (tunnel_ctrl_tx, mut tunnel_ctrl_rx) = mpsc::channel::<Vec<u8>>(64);
+    let (tunnel_data_tx, mut tunnel_data_rx) = mpsc::channel::<Vec<u8>>(4096);
+    // Legacy alias — control channel for PONG, CLOSE, WINDOW_UPDATE, OPEN
+    let tunnel_writer_tx = tunnel_ctrl_tx.clone();
     let tw_token = connection_token.clone();
     let tunnel_writer_handle = tokio::spawn(async move {
+        // BufWriter coalesces small writes (frame headers, control frames) into fewer
+        // TLS records and syscalls. Flushed after each frame to avoid holding data.
+        let mut writer = tokio::io::BufWriter::with_capacity(65536, write_half);
         loop {
             tokio::select! {
-                data = tunnel_writer_rx.recv() => {
+                biased; // control frames always take priority over data
+                ctrl = tunnel_ctrl_rx.recv() => {
+                    match ctrl {
+                        Some(frame_data) => {
+                            if writer.write_all(&frame_data).await.is_err() { break; }
+                            if writer.flush().await.is_err() { break; }
+                        }
+                        None => break,
+                    }
+                }
+                data = tunnel_data_rx.recv() => {
                     match data {
                         Some(frame_data) => {
-                            if write_half.write_all(&frame_data).await.is_err() {
-                                break;
-                            }
+                            if writer.write_all(&frame_data).await.is_err() { break; }
+                            if writer.flush().await.is_err() { break; }
                         }
                         None => break,
                     }
@@ -393,6 +416,7 @@ async fn connect_to_hub_and_run(
         &handshake.listen_ports,
         &mut port_listeners,
         &tunnel_writer_tx,
+        &tunnel_data_tx,
         &client_writers,
         active_streams,
         next_stream_id,
@@ -458,6 +482,7 @@ async fn connect_to_hub_and_run(
                                         &update.listen_ports,
                                         &mut port_listeners,
                                         &tunnel_writer_tx,
+                                        &tunnel_data_tx,
                                         &client_writers,
                                         active_streams,
                                         next_stream_id,
@@ -519,7 +544,8 @@ async fn connect_to_hub_and_run(
 fn apply_port_config(
     new_ports: &[u16],
     port_listeners: &mut HashMap<u16, JoinHandle<()>>,
-    tunnel_writer_tx: &mpsc::Sender<Vec<u8>>,
+    tunnel_ctrl_tx: &mpsc::Sender<Vec<u8>>,
+    tunnel_data_tx: &mpsc::Sender<Vec<u8>>,
     client_writers: &Arc<Mutex<HashMap<u32, EdgeStreamState>>>,
     active_streams: &Arc<AtomicU32>,
     next_stream_id: &Arc<AtomicU32>,
@@ -539,7 +565,8 @@ fn apply_port_config(
 
     // Add new ports
     for &port in new_set.difference(&old_set) {
-        let tunnel_writer_tx = tunnel_writer_tx.clone();
+        let tunnel_ctrl_tx = tunnel_ctrl_tx.clone();
+        let tunnel_data_tx = tunnel_data_tx.clone();
         let client_writers = client_writers.clone();
         let active_streams = active_streams.clone();
         let next_stream_id = next_stream_id.clone();
@@ -562,7 +589,8 @@ fn apply_port_config(
                         match accept_result {
                             Ok((client_stream, client_addr)) => {
                                 let stream_id = next_stream_id.fetch_add(1, Ordering::Relaxed);
-                                let tunnel_writer_tx = tunnel_writer_tx.clone();
+                                let tunnel_ctrl_tx = tunnel_ctrl_tx.clone();
+                                let tunnel_data_tx = tunnel_data_tx.clone();
                                 let client_writers = client_writers.clone();
                                 let active_streams = active_streams.clone();
                                 let edge_id = edge_id.clone();
@@ -577,7 +605,8 @@ fn apply_port_config(
                                         stream_id,
                                         port,
                                         &edge_id,
-                                        tunnel_writer_tx,
+                                        tunnel_ctrl_tx,
+                                        tunnel_data_tx,
                                         client_writers,
                                         client_token,
                                     )
@@ -607,7 +636,8 @@ async fn handle_client_connection(
     stream_id: u32,
     dest_port: u16,
     edge_id: &str,
-    tunnel_writer_tx: mpsc::Sender<Vec<u8>>,
+    tunnel_ctrl_tx: mpsc::Sender<Vec<u8>>,
+    tunnel_data_tx: mpsc::Sender<Vec<u8>>,
     client_writers: Arc<Mutex<HashMap<u32, EdgeStreamState>>>,
     client_token: CancellationToken,
 ) {
@@ -617,15 +647,15 @@ async fn handle_client_connection(
     // Determine edge IP (use 0.0.0.0 as placeholder — hub doesn't use it for routing)
     let edge_ip = "0.0.0.0";
 
-    // Send OPEN frame with PROXY v1 header via writer channel
+    // Send OPEN frame with PROXY v1 header via control channel
     let proxy_header = build_proxy_v1_header(&client_ip, edge_ip, client_port, dest_port);
     let open_frame = encode_frame(stream_id, FRAME_OPEN, proxy_header.as_bytes());
-    if tunnel_writer_tx.send(open_frame).await.is_err() {
+    if tunnel_ctrl_tx.send(open_frame).await.is_err() {
         return;
     }
 
     // Set up channel for data coming back from hub (capacity 16 is sufficient with flow control)
-    let (back_tx, mut back_rx) = mpsc::channel::<Vec<u8>>(128);
+    let (back_tx, mut back_rx) = mpsc::channel::<Vec<u8>>(256);
     let send_window = Arc::new(AtomicU32::new(INITIAL_STREAM_WINDOW));
     let window_notify = Arc::new(Notify::new());
     {
@@ -642,8 +672,8 @@ async fn handle_client_connection(
     // Task: hub -> client (download direction)
     // After writing to client TCP, send WINDOW_UPDATE to hub so it can send more
     let hub_to_client_token = client_token.clone();
-    let wu_tx = tunnel_writer_tx.clone();
-    let hub_to_client = tokio::spawn(async move {
+    let wu_tx = tunnel_ctrl_tx.clone();
+    let mut hub_to_client = tokio::spawn(async move {
         let mut consumed_since_update: u32 = 0;
         loop {
             tokio::select! {
@@ -657,10 +687,11 @@ async fn handle_client_connection(
                             // Track consumption for flow control
                             consumed_since_update += len;
                             if consumed_since_update >= WINDOW_UPDATE_THRESHOLD {
-                                let increment = consumed_since_update;
-                                consumed_since_update = 0;
-                                let frame = encode_window_update(stream_id, FRAME_WINDOW_UPDATE, increment);
-                                let _ = wu_tx.try_send(frame);
+                                let frame = encode_window_update(stream_id, FRAME_WINDOW_UPDATE, consumed_since_update);
+                                if wu_tx.try_send(frame).is_ok() {
+                                    consumed_since_update = 0;
+                                }
+                                // If try_send fails, keep accumulating — retry on next threshold
                             }
                         }
                         None => break,
@@ -680,19 +711,30 @@ async fn handle_client_connection(
     // Task: client -> hub (upload direction) with per-stream flow control
     let mut buf = vec![0u8; 32768];
     loop {
-        // Wait for send window to have capacity
+        // Wait for send window to have capacity (with stall timeout)
         loop {
             let w = send_window.load(Ordering::Acquire);
             if w > 0 { break; }
             tokio::select! {
                 _ = window_notify.notified() => continue,
                 _ = client_token.cancelled() => break,
+                _ = tokio::time::sleep(Duration::from_secs(120)) => {
+                    log::warn!("Stream {} upload stalled (window empty for 120s)", stream_id);
+                    break;
+                }
             }
         }
         if client_token.is_cancelled() { break; }
 
-        // Limit read size to available window
+        // Limit read size to available window.
+        // IMPORTANT: if window is 0 (stall timeout fired), we must NOT
+        // read into an empty buffer — read(&mut buf[..0]) returns Ok(0)
+        // which would be falsely interpreted as EOF.
         let w = send_window.load(Ordering::Acquire) as usize;
+        if w == 0 {
+            log::warn!("Stream {} upload: window still 0 after stall timeout, closing", stream_id);
+            break;
+        }
         let max_read = w.min(buf.len());
 
         tokio::select! {
@@ -702,8 +744,8 @@ async fn handle_client_connection(
                     Ok(n) => {
                         send_window.fetch_sub(n as u32, Ordering::Release);
                         let data_frame = encode_frame(stream_id, FRAME_DATA, &buf[..n]);
-                        if tunnel_writer_tx.send(data_frame).await.is_err() {
-                            log::warn!("Stream {} tunnel writer closed, closing", stream_id);
+                        if tunnel_data_tx.send(data_frame).await.is_err() {
+                            log::warn!("Stream {} data channel closed, closing", stream_id);
                             break;
                         }
                     }
@@ -714,18 +756,29 @@ async fn handle_client_connection(
         }
     }
 
-    // Send CLOSE frame (only if not cancelled)
+    // Wait for the download task (hub → client) to finish BEFORE sending CLOSE.
+    // Upload EOF (client done sending) does NOT mean the response is done.
+    // For asymmetric transfers like git fetch (small request, large response),
+    // the response is still streaming when the upload finishes.
+    // Sending CLOSE before the response finishes would cause the hub to cancel
+    // the upstream reader mid-response, truncating the data.
+    let _ = tokio::time::timeout(
+        Duration::from_secs(300),  // 5 min max wait for download to finish
+        &mut hub_to_client,
+    ).await;
+
+    // NOW send CLOSE — the response has been fully delivered (or timed out).
     if !client_token.is_cancelled() {
         let close_frame = encode_frame(stream_id, FRAME_CLOSE, &[]);
-        let _ = tunnel_writer_tx.try_send(close_frame);
+        let _ = tunnel_data_tx.send(close_frame).await;
     }
 
-    // Cleanup
+    // Clean up
     {
         let mut writers = client_writers.lock().await;
         writers.remove(&stream_id);
     }
-    hub_to_client.abort();
+    hub_to_client.abort(); // No-op if already finished; safety net if timeout fired
     let _ = edge_id; // used for logging context
 }
 

rust/crates/remoteingress-core/src/hub.rs

@@ -298,6 +298,8 @@ async fn handle_edge_connection(
     edge_token: CancellationToken,
     peer_addr: String,
 ) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    // Disable Nagle's algorithm for low-latency control frames (PING/PONG, WINDOW_UPDATE)
+    stream.set_nodelay(true)?;
     let tls_stream = acceptor.accept(stream).await?;
     let (read_half, mut write_half) = tokio::io::split(tls_stream);
     let mut buf_reader = BufReader::new(read_half);
@@ -371,19 +373,34 @@ async fn handle_edge_connection(
         );
     }
 
-    // A5: Channel-based writer replaces Arc<Mutex<WriteHalf>>
-    // All frame writes go through this channel → dedicated writer task serializes them
-    let (frame_writer_tx, mut frame_writer_rx) = mpsc::channel::<Vec<u8>>(4096);
+    // QoS dual-channel tunnel writer: control frames (PING/PONG/WINDOW_UPDATE/CLOSE)
+    // have priority over data frames (DATA_BACK). This prevents PING starvation under load.
+    let (ctrl_tx, mut ctrl_rx) = mpsc::channel::<Vec<u8>>(64);
+    let (data_tx, mut data_rx) = mpsc::channel::<Vec<u8>>(4096);
+    // Legacy alias for code that sends both control and data (will be migrated)
+    let frame_writer_tx = ctrl_tx.clone();
     let writer_token = edge_token.clone();
     let writer_handle = tokio::spawn(async move {
+        // BufWriter coalesces small writes (frame headers, control frames) into fewer
+        // TLS records and syscalls. Flushed after each frame to avoid holding data.
+        let mut writer = tokio::io::BufWriter::with_capacity(65536, write_half);
         loop {
             tokio::select! {
-                data = frame_writer_rx.recv() => {
+                biased; // control frames always take priority over data
+                ctrl = ctrl_rx.recv() => {
+                    match ctrl {
+                        Some(frame_data) => {
+                            if writer.write_all(&frame_data).await.is_err() { break; }
+                            if writer.flush().await.is_err() { break; }
+                        }
+                        None => break,
+                    }
+                }
+                data = data_rx.recv() => {
                     match data {
                         Some(frame_data) => {
-                            if write_half.write_all(&frame_data).await.is_err() {
-                                break;
-                            }
+                            if writer.write_all(&frame_data).await.is_err() { break; }
+                            if writer.flush().await.is_err() { break; }
                         }
                         None => break,
                     }
@@ -467,7 +484,8 @@ async fn handle_edge_connection(
                                 let edge_id_clone = edge_id.clone();
                                 let event_tx_clone = event_tx.clone();
                                 let streams_clone = streams.clone();
-                                let writer_tx = frame_writer_tx.clone();
+                                let writer_tx = ctrl_tx.clone();   // control: CLOSE_BACK, WINDOW_UPDATE_BACK
+                                let data_writer_tx = data_tx.clone(); // data: DATA_BACK
                                 let target = target_host.clone();
                                 let stream_token = edge_token.child_token();
 
@@ -477,7 +495,7 @@ async fn handle_edge_connection(
                                 });
 
                                 // Create channel for data from edge to this stream (capacity 16 is sufficient with flow control)
-                                let (data_tx, mut data_rx) = mpsc::channel::<Vec<u8>>(128);
+                                let (data_tx, mut data_rx) = mpsc::channel::<Vec<u8>>(256);
                                 let send_window = Arc::new(AtomicU32::new(INITIAL_STREAM_WINDOW));
                                 let window_notify = Arc::new(Notify::new());
                                 {
@@ -505,6 +523,7 @@ async fn handle_edge_connection(
                                             format!("connect to SmartProxy {}:{} timed out (10s)", target, dest_port).into()
                                         })??;
 
+                                        upstream.set_nodelay(true)?;
                                         upstream.write_all(proxy_header.as_bytes()).await?;
 
                                         let (mut up_read, mut up_write) =
@@ -522,16 +541,31 @@ async fn handle_edge_connection(
                                                         match data {
                                                             Some(data) => {
                                                                 let len = data.len() as u32;
-                                                                if up_write.write_all(&data).await.is_err() {
-                                                                    break;
+                                                                // Check cancellation alongside the write so we respond
+                                                                // promptly to FRAME_CLOSE instead of blocking up to 60s.
+                                                                let write_result = tokio::select! {
+                                                                    r = tokio::time::timeout(
+                                                                        Duration::from_secs(60),
+                                                                        up_write.write_all(&data),
+                                                                    ) => r,
+                                                                    _ = writer_token.cancelled() => break,
+                                                                };
+                                                                match write_result {
+                                                                    Ok(Ok(())) => {}
+                                                                    Ok(Err(_)) => break,
+                                                                    Err(_) => {
+                                                                        log::warn!("Stream {} write to upstream timed out (60s)", stream_id);
+                                                                        break;
+                                                                    }
                                                                 }
                                                                 // Track consumption for flow control
                                                                 consumed_since_update += len;
                                                                 if consumed_since_update >= WINDOW_UPDATE_THRESHOLD {
-                                                                    let increment = consumed_since_update;
-                                                                    consumed_since_update = 0;
-                                                                    let frame = encode_window_update(stream_id, FRAME_WINDOW_UPDATE_BACK, increment);
-                                                                    let _ = wub_tx.try_send(frame);
+                                                                    let frame = encode_window_update(stream_id, FRAME_WINDOW_UPDATE_BACK, consumed_since_update);
+                                                                    if wub_tx.try_send(frame).is_ok() {
+                                                                        consumed_since_update = 0;
+                                                                    }
+                                                                    // If try_send fails, keep accumulating — retry on next threshold
                                                                 }
                                                             }
                                                             None => break,
@@ -552,19 +586,30 @@ async fn handle_edge_connection(
                                         // with per-stream flow control (check send_window before reading)
                                         let mut buf = vec![0u8; 32768];
                                         loop {
-                                            // Wait for send window to have capacity
+                                            // Wait for send window to have capacity (with stall timeout)
                                             loop {
                                                 let w = send_window.load(Ordering::Acquire);
                                                 if w > 0 { break; }
                                                 tokio::select! {
                                                     _ = window_notify.notified() => continue,
                                                     _ = stream_token.cancelled() => break,
+                                                    _ = tokio::time::sleep(Duration::from_secs(120)) => {
+                                                        log::warn!("Stream {} download stalled (window empty for 120s)", stream_id);
+                                                        break;
+                                                    }
                                                 }
                                             }
                                             if stream_token.is_cancelled() { break; }
 
-                                            // Limit read size to available window
+                                            // Limit read size to available window.
+                                            // IMPORTANT: if window is 0 (stall timeout fired), we must NOT
+                                            // read into an empty buffer — read(&mut buf[..0]) returns Ok(0)
+                                            // which would be falsely interpreted as EOF.
                                             let w = send_window.load(Ordering::Acquire) as usize;
+                                            if w == 0 {
+                                                log::warn!("Stream {} download: window still 0 after stall timeout, closing", stream_id);
+                                                break;
+                                            }
                                             let max_read = w.min(buf.len());
 
                                             tokio::select! {
@@ -575,8 +620,8 @@ async fn handle_edge_connection(
                                                             send_window.fetch_sub(n as u32, Ordering::Release);
                                                             let frame =
                                                                 encode_frame(stream_id, FRAME_DATA_BACK, &buf[..n]);
-                                                            if writer_tx.send(frame).await.is_err() {
-                                                                log::warn!("Stream {} writer channel closed, closing", stream_id);
+                                                            if data_writer_tx.send(frame).await.is_err() {
+                                                                log::warn!("Stream {} data channel closed, closing", stream_id);
                                                                 break;
                                                             }
                                                         }
@@ -587,10 +632,11 @@ async fn handle_edge_connection(
                                             }
                                         }
 
-                                        // Send CLOSE_BACK to edge (only if not cancelled)
+                                        // Send CLOSE_BACK via DATA channel (must arrive AFTER last DATA_BACK).
+                                        // Use send().await to guarantee delivery (try_send silently drops if full).
                                         if !stream_token.is_cancelled() {
                                             let close_frame = encode_frame(stream_id, FRAME_CLOSE_BACK, &[]);
-                                            let _ = writer_tx.try_send(close_frame);
+                                            let _ = data_writer_tx.send(close_frame).await;
                                         }
 
                                         writer_for_edge_data.abort();
@@ -600,10 +646,11 @@ async fn handle_edge_connection(
 
                                     if let Err(e) = result {
                                         log::error!("Stream {} error: {}", stream_id, e);
-                                        // Send CLOSE_BACK on error (only if not cancelled)
+                                        // Send CLOSE_BACK via DATA channel on error (must arrive after any DATA_BACK).
+                                        // Use send().await to guarantee delivery.
                                         if !stream_token.is_cancelled() {
                                             let close_frame = encode_frame(stream_id, FRAME_CLOSE_BACK, &[]);
-                                            let _ = writer_tx.try_send(close_frame);
+                                            let _ = data_writer_tx.send(close_frame).await;
                                         }
                                     }
 

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@serve.zone/remoteingress',
-  version: '4.5.1',
+  version: '4.5.10',
   description: 'Edge ingress tunnel for DcRouter - accepts incoming TCP connections at network edge and tunnels them to DcRouter SmartProxy preserving client IP via PROXY protocol v1.'
 }