From 300ab1a0778335fc8ad9c922f9347a642b8f6b60 Mon Sep 17 00:00:00 2001
From: Philipp Kunz <code@philkunz.com>
Date: Sun, 1 Jun 2025 13:42:46 +0000
Subject: [PATCH] Fix connection leak in route-connection-handler by using safe
 socket creation

The previous fix only addressed ForwardingHandler classes but missed the critical setupDirectConnection() method in route-connection-handler.ts where SmartProxy actually handles connections. This caused active connections to rise indefinitely on ECONNREFUSED errors.

Changes:
- Import createSocketWithErrorHandler in route-connection-handler.ts
- Replace net.connect() with createSocketWithErrorHandler() in setupDirectConnection()
- Properly clean up connection records when server connection fails
- Add connectionFailed flag to prevent setup of failed connections

This ensures connection records are cleaned up immediately when backend connections fail, preventing memory leaks.
---
 readme.hints.md                               |  9 +++-
 .../smart-proxy/route-connection-handler.ts   | 54 ++++++++++++++++---
 2 files changed, 55 insertions(+), 8 deletions(-)

diff --git a/readme.hints.md b/readme.hints.md
index 09f85d7..29b74dd 100644
--- a/readme.hints.md
+++ b/readme.hints.md
@@ -457,4 +457,11 @@ const socket = createSocketWithErrorHandler({
 - `test/test.forwarding-error-fix.node.ts` - Tests forwarding handlers handle errors gracefully
 
 ### Configuration
-No configuration changes needed. The fix is transparent to users.
\ No newline at end of file
+No configuration changes needed. The fix is transparent to users.
+
+### Important Note
+The fix was applied in two places:
+1. **ForwardingHandler classes** (`https-passthrough-handler.ts`, etc.) - These are standalone forwarding utilities
+2. **SmartProxy route-connection-handler** (`route-connection-handler.ts`) - This is where the actual SmartProxy connection handling happens
+
+The critical fix for SmartProxy was in `setupDirectConnection()` method in route-connection-handler.ts, which now uses `createSocketWithErrorHandler()` to properly handle connection failures and clean up connection records.
\ No newline at end of file
diff --git a/ts/proxies/smart-proxy/route-connection-handler.ts b/ts/proxies/smart-proxy/route-connection-handler.ts
index 3e90342..282c79b 100644
--- a/ts/proxies/smart-proxy/route-connection-handler.ts
+++ b/ts/proxies/smart-proxy/route-connection-handler.ts
@@ -9,7 +9,7 @@ import { TlsManager } from './tls-manager.js';
 import { HttpProxyBridge } from './http-proxy-bridge.js';
 import { TimeoutManager } from './timeout-manager.js';
 import { RouteManager } from './route-manager.js';
-import { cleanupSocket, createIndependentSocketHandlers, setupSocketHandlers } from '../../core/utils/socket-utils.js';
+import { cleanupSocket, createIndependentSocketHandlers, setupSocketHandlers, createSocketWithErrorHandler } from '../../core/utils/socket-utils.js';
 
 /**
  * Handles new connection processing and setup logic with support for route-based configuration
@@ -1073,13 +1073,52 @@ export class RouteConnectionHandler {
       record.pendingDataSize = initialChunk.length;
     }
 
-    // Create the target socket
-    const targetSocket = plugins.net.connect(connectionOptions);
-    record.outgoing = targetSocket;
-    record.outgoingStartTime = Date.now();
+    // Create the target socket with immediate error handling
+    let targetSocket: plugins.net.Socket;
+    
+    // Flag to track if initial connection failed
+    let connectionFailed = false;
+    
+    targetSocket = createSocketWithErrorHandler({
+      port: finalTargetPort,
+      host: finalTargetHost,
+      onError: (error) => {
+        // Mark connection as failed
+        connectionFailed = true;
+        
+        // Connection failed - clean up immediately
+        logger.log('error', 
+          `Connection setup error for ${connectionId} to ${finalTargetHost}:${finalTargetPort}: ${error.message} (${(error as any).code})`, 
+          {
+            connectionId,
+            targetHost: finalTargetHost,
+            targetPort: finalTargetPort,
+            errorMessage: error.message,
+            errorCode: (error as any).code,
+            component: 'route-handler'
+          }
+        );
+        
+        // Resume the incoming socket to prevent it from hanging
+        socket.resume();
+        
+        // Clean up the incoming socket
+        if (!socket.destroyed) {
+          socket.destroy();
+        }
+        
+        // Clean up the connection record
+        this.connectionManager.initiateCleanupOnce(record, `connection_failed_${(error as any).code || 'unknown'}`);
+      }
+    });
+    
+    // Only proceed with setup if connection didn't fail immediately
+    if (!connectionFailed) {
+      record.outgoing = targetSocket;
+      record.outgoingStartTime = Date.now();
 
-    // Apply socket optimizations
-    targetSocket.setNoDelay(this.settings.noDelay);
+      // Apply socket optimizations
+      targetSocket.setNoDelay(this.settings.noDelay);
 
     // Apply keep-alive settings if enabled
     if (this.settings.keepAlive) {
@@ -1346,5 +1385,6 @@ export class RouteConnectionHandler {
         record.tlsHandshakeComplete = true;
       }
     });
+    } // End of if (!connectionFailed)
   }
 }
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