Enhance socket cleanup and management for improved connection handling

- Refactor cleanupSocket function to support options for immediate destruction, allowing drain, and grace periods.
- Introduce createIndependentSocketHandlers for better management of half-open connections between client and server sockets.
- Update various handlers (HTTP, HTTPS passthrough, HTTPS terminate) to utilize new cleanup and socket management functions.
- Implement custom timeout handling in socket setup to prevent immediate closure during keep-alive connections.
- Add tests for long-lived connections and half-open connection scenarios to ensure stability and reliability.
- Adjust connection manager to handle socket cleanup based on activity status, improving resource management.

ts/forwarding/handlers/http-handler.ts

@@ -49,7 +49,12 @@ export class HttpForwardingHandler extends ForwardingHandler {
       });
     };
     
-    setupSocketHandlers(socket, handleClose, 'http');
+    // Use custom timeout handler that doesn't close the socket
+    setupSocketHandlers(socket, handleClose, () => {
+      // For HTTP, we can be more aggressive with timeouts since connections are shorter
+      // But still don't close immediately - let the connection finish naturally
+      console.warn(`HTTP socket timeout from ${remoteAddress}`);
+    }, 'http');
     
     socket.on('error', (error) => {
       this.emit(ForwardingHandlerEvents.ERROR, {

ts/forwarding/handlers/https-passthrough-handler.ts

@@ -2,7 +2,7 @@ import * as plugins from '../../plugins.js';
 import { ForwardingHandler } from './base-handler.js';
 import type { IForwardConfig } from '../config/forwarding-types.js';
 import { ForwardingHandlerEvents } from '../config/forwarding-types.js';
-import { createSocketCleanupHandler, setupSocketHandlers, pipeSockets } from '../../core/utils/socket-utils.js';
+import { createIndependentSocketHandlers, setupSocketHandlers } from '../../core/utils/socket-utils.js';
 
 /**
  * Handler for HTTPS passthrough (SNI forwarding without termination)
@@ -55,19 +55,32 @@ export class HttpsPassthroughHandler extends ForwardingHandler {
     let bytesSent = 0;
     let bytesReceived = 0;
     
-    // Create cleanup handler with our utility
-    const handleClose = createSocketCleanupHandler(clientSocket, serverSocket, (reason) => {
-      this.emit(ForwardingHandlerEvents.DISCONNECTED, {
-        remoteAddress,
-        bytesSent,
-        bytesReceived,
-        reason
-      });
-    });
+    // Create independent handlers for half-open connection support
+    const { cleanupClient, cleanupServer } = createIndependentSocketHandlers(
+      clientSocket,
+      serverSocket,
+      (reason) => {
+        this.emit(ForwardingHandlerEvents.DISCONNECTED, {
+          remoteAddress,
+          bytesSent,
+          bytesReceived,
+          reason
+        });
+      }
+    );
     
-    // Setup error and close handlers for both sockets
-    setupSocketHandlers(serverSocket, handleClose, 'server');
-    setupSocketHandlers(clientSocket, handleClose, 'client');
+    // Setup handlers with custom timeout handling that doesn't close connections
+    const timeout = this.getTimeout();
+    
+    setupSocketHandlers(clientSocket, cleanupClient, (socket) => {
+      // Just reset timeout, don't close
+      socket.setTimeout(timeout);
+    }, 'client');
+    
+    setupSocketHandlers(serverSocket, cleanupServer, (socket) => {
+      // Just reset timeout, don't close  
+      socket.setTimeout(timeout);
+    }, 'server');
     
     // Forward data from client to server
     clientSocket.on('data', (data) => {
@@ -117,8 +130,7 @@ export class HttpsPassthroughHandler extends ForwardingHandler {
       });
     });
     
-    // Set timeouts
-    const timeout = this.getTimeout();
+    // Set initial timeouts - they will be reset on each timeout event  
     clientSocket.setTimeout(timeout);
     serverSocket.setTimeout(timeout);
   }
@@ -128,7 +140,7 @@ export class HttpsPassthroughHandler extends ForwardingHandler {
    * @param req The HTTP request
    * @param res The HTTP response
    */
-  public handleHttpRequest(req: plugins.http.IncomingMessage, res: plugins.http.ServerResponse): void {
+  public handleHttpRequest(_req: plugins.http.IncomingMessage, res: plugins.http.ServerResponse): void {
     // HTTPS passthrough doesn't support HTTP requests
     res.writeHead(404, { 'Content-Type': 'text/plain' });
     res.end('HTTP not supported for this domain');

ts/forwarding/handlers/https-terminate-to-http-handler.ts

@@ -112,7 +112,7 @@ export class HttpsTerminateToHttpHandler extends ForwardingHandler {
     });
     
     // Set up error handling with our cleanup utility
-    setupSocketHandlers(tlsSocket, handleClose, 'tls');
+    setupSocketHandlers(tlsSocket, handleClose, undefined, 'tls');
     
     // Set timeout
     const timeout = this.getTimeout();
@@ -167,7 +167,7 @@ export class HttpsTerminateToHttpHandler extends ForwardingHandler {
         });
         
         // Set up handlers for backend socket
-        setupSocketHandlers(backendSocket, newHandleClose, 'backend');
+        setupSocketHandlers(backendSocket, newHandleClose, undefined, 'backend');
         
         backendSocket.on('error', (error) => {
           this.emit(ForwardingHandlerEvents.ERROR, {

ts/forwarding/handlers/https-terminate-to-https-handler.ts

@@ -106,7 +106,7 @@ export class HttpsTerminateToHttpsHandler extends ForwardingHandler {
     });
     
     // Set up error handling with our cleanup utility
-    setupSocketHandlers(tlsSocket, handleClose, 'tls');
+    setupSocketHandlers(tlsSocket, handleClose, undefined, 'tls');
     
     // Set timeout
     const timeout = this.getTimeout();
@@ -151,7 +151,7 @@ export class HttpsTerminateToHttpsHandler extends ForwardingHandler {
       });
       
       // Set up handlers for backend socket
-      setupSocketHandlers(backendSocket, newHandleClose, 'backend');
+      setupSocketHandlers(backendSocket, newHandleClose, undefined, 'backend');
       
       backendSocket.on('error', (error) => {
         this.emit(ForwardingHandlerEvents.ERROR, {