private void ConnectToRemoteCallback(IAsyncResult asyncResult)
{
ForwarderPair pair = (ForwarderPair)asyncResult.AsyncState;
if (!asyncResult.AsyncWaitHandle.WaitOne(remoteConnectTimeoutMillis))
{
Console.WriteLine("Failed to connect to remote host, closing connections");
pair.LocalClient.Close();
return;
}
try
{
pair.RemoteClient.EndConnect(asyncResult);
if (pair.LocalClient.Connected && pair.RemoteClient.Connected)
{
pair.LocalEndPoint = pair.RemoteClient.Client.LocalEndPoint;
pair.RemoteEndpoint = pair.RemoteClient.Client.RemoteEndPoint;
Console.WriteLine("Connected client " + pair.LocalEndPoint + " to " + pair.RemoteEndpoint);
lock (clients)
{
clients.Add(pair);
}
StartForwarding(pair);
}
}
catch (Exception e)
{
Console.WriteLine("Error connecting to remote host, : " + e.Message);
}
}
private void ConnectToRemote(TcpClient client)
{
ForwarderPair pair = new ForwarderPair();
pair.LocalClient = client;
pair.RemoteClient = new TcpClient();
pair.RemoteClient.BeginConnect(settings.DestinationIP, settings.DestinationPort, ConnectToRemoteCallback, state: pair);
}
private void StartForwarding(ForwarderPair pair)
{
try
{
BeginLocalReceive(pair);
BeginRemoteReceive(pair);
Console.WriteLine($"Forwarding: {pair.LocalEndPoint} <----> {pair.RemoteEndpoint}");
}
catch
{
DisconnectPair(pair);
}
}
private void RemoteReceiveCallback(IAsyncResult asyncResult)
{
ForwarderPair pair = (ForwarderPair)asyncResult.AsyncState;
int readBytes = pair.RemoteClient.GetStream().EndRead(asyncResult);
if (readBytes > 0)
{
pair.LocalClient.GetStream().Write(pair.RemoteBuffer, 0, readBytes);
}
//продолжаем принимать
BeginRemoteReceive(pair);
}
private void LocalReceiveCallback(IAsyncResult asyncResult)
{
ForwarderPair pair = (ForwarderPair)asyncResult.AsyncState;
int bytesRead = pair.LocalClient.GetStream().EndRead(asyncResult);
if (bytesRead > 0)
{
pair.RemoteClient.GetStream().Write(pair.LocalBuffer, 0, bytesRead);
}
//продолжаем принимать
BeginLocalReceive(pair);
}
private void DisconnectPair(ForwarderPair pair)
{
lock (clients)
{
clients.Remove(pair);
}
Console.WriteLine("Forwarding terminated: " + pair.LocalEndPoint + " <--X--> " + pair.RemoteEndpoint);
pair.LocalClient.GetStream().Close();
pair.LocalClient.Close();
pair.RemoteClient.GetStream().Close();
pair.RemoteClient.Close();
}
private void BeginRemoteReceive(ForwarderPair pair)
{
pair.RemoteClient.GetStream().BeginRead(pair.RemoteBuffer, 0, pair.RemoteBuffer.Length, RemoteReceiveCallback, pair);
}
private void BeginLocalReceive(ForwarderPair pair)
{
pair.LocalClient.GetStream().BeginRead(pair.LocalBuffer, 0, pair.LocalBuffer.Length, LocalReceiveCallback, pair);
}