I am building a tcp port forwarding application. The client connects to the server on a particular port and internally the request is routed in the server to a remote port and response is passed back to the client. Below is my code.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace BBGRouter
{
class Router
{
#region log4net
private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
#endregion //log4net
bool isShutdown = false;
private Socket router = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
public event EventHandler OnRestartNeeded;
//only one time
Thread thRouterTh;
public Router()
{
thRouterTh = new Thread(new ParameterizedThreadStart(RouterProc));
}
IPEndPoint local, remote;
public void Start(IPEndPoint local, IPEndPoint remote)
{
if (log.IsInfoEnabled) { log.Info("Listening on " + local); }
this.local = local;
this.remote = remote;
router.Bind(local);
router.Listen(10);
thRouterTh.Name = "router thread";
thRouterTh.Start();
}
void RouterProc(object obj)
{
while (!isShutdown)
{
try
{
var source = router.Accept();
if (log.IsInfoEnabled) { log.Info("Creating new session...."); }
var destination = new Router();
var state = new State(source, destination.router);
destination.Connect(remote, source);
source.BeginReceive(state.Buffer, 0, state.Buffer.Length, 0, OnDataReceive, state);
}
catch (Exception ex)
{
if (log.IsErrorEnabled) { log.Error("Exception in Router thread", ex); }
if (isShutdown) { if (log.IsInfoEnabled) { log.Info("Shutting down..."); } }
}
}
}
public void Join()
{
if (thRouterTh != null)
thRouterTh.Join();
}
private void StopAndFireRestart(EventArgs e)
{
Stop();
log.Info("Stopped router");
EventHandler handler = OnRestartNeeded;
if (handler != null)
{
log.Info("Firing the restart event now");
handler(this, e);
}
}
public void Stop()
{
try
{
isShutdown = true;
if (log.IsInfoEnabled) { log.Info("Stopping router thread"); }
router.Shutdown(SocketShutdown.Both);
//router.Shutdown(SocketShutdown.Receive);
}
catch (Exception ex)
{
if (log.IsErrorEnabled) { log.Error("Exception while stopping", ex); }
}
finally
{
thRouterTh.Interrupt();
router.Dispose();
}
}
private void Connect(EndPoint remoteEndpoint, Socket destination)
{
if (log.IsInfoEnabled) { log.InfoFormat("connecting session at {0}", remoteEndpoint.ToString()); }
var state = new State(router, destination);
try
{
router.Connect(remoteEndpoint);
router.BeginReceive(state.Buffer, 0, state.Buffer.Length, SocketFlags.None, OnDataReceive, state);
}
catch (SocketException e)
{
if (log.IsErrorEnabled) { log.Error(string.Format("SocketException while connect: Exception: {0}, ErrorCode: {1}", e, e.ErrorCode)); }
// Stop the service
StopAndFireRestart(new EventArgs());
}
catch (Exception ex)
{
if (log.IsErrorEnabled) { log.Error("exception while connect {0}", ex); }
}
}
private void OnDataReceive(IAsyncResult result)
{
var state = (State)result.AsyncState;
try
{
var bytesRead = state.SourceSocket.EndReceive(result);
if (bytesRead > 0)
{
log.Info(string.Format("Bytes read: {0}", bytesRead));
state.DestinationSocket.Send(state.Buffer, bytesRead, SocketFlags.None);
state.SourceSocket.BeginReceive(state.Buffer, 0, state.Buffer.Length, 0, OnDataReceive, state);
}
}
catch (Exception e)
{
if (log.IsErrorEnabled) { log.Error("Exception receiving the data, Closing source/destination sockets", e); }
//state.DestinationSocket.Close();
//state.SourceSocket.Close();
//StopAndFireRestart(new EventArgs());
}
}
private class State
{
public Socket SourceSocket { get; private set; }
public Socket DestinationSocket { get; private set; }
public byte[] Buffer { get; private set; }
public State(Socket source, Socket destination)
{
SourceSocket = source;
DestinationSocket = destination;
Buffer = new byte[8192];
}
}
}
}
The problem happens when suddenly the client gets disconnected from the remote port randomly after 4-5 hrs. How can I reconnect the client gracefully so that there is no change in the client code ?
