From 679b247c8a60d10271c761356cd186153fc3eb37 Mon Sep 17 00:00:00 2001
From: Juergen Kunz <juergen@foss.global>
Date: Mon, 16 Mar 2026 09:36:03 +0000
Subject: [PATCH] fix(remoteingress-core): disable Nagle's algorithm on edge,
 hub, and upstream TCP sockets to reduce control-frame latency

---
 changelog.md                               | 7 +++++++
 rust/crates/remoteingress-core/src/edge.rs | 6 +++++-
 rust/crates/remoteingress-core/src/hub.rs  | 3 +++
 ts/00_commitinfo_data.ts                   | 2 +-
 4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/changelog.md b/changelog.md
index 0e44f8d..aa76ecb 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,12 @@
 # Changelog
 
+## 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
 
diff --git a/rust/crates/remoteingress-core/src/edge.rs b/rust/crates/remoteingress-core/src/edge.rs
index ad0709f..fb9b70d 100644
--- a/rust/crates/remoteingress-core/src/edge.rs
+++ b/rust/crates/remoteingress-core/src/edge.rs
@@ -270,7 +270,11 @@ async fn connect_to_hub_and_run(
 
     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;
diff --git a/rust/crates/remoteingress-core/src/hub.rs b/rust/crates/remoteingress-core/src/hub.rs
index 6941c95..e92df02 100644
--- a/rust/crates/remoteingress-core/src/hub.rs
+++ b/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);
@@ -520,6 +522,7 @@ 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) =
diff --git a/ts/00_commitinfo_data.ts b/ts/00_commitinfo_data.ts
index 1a19805..a61fc70 100644
--- a/ts/00_commitinfo_data.ts
+++ b/ts/00_commitinfo_data.ts
@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@serve.zone/remoteingress',
-  version: '4.5.5',
+  version: '4.5.6',
   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.'
 }