private async void ProcessLocalConnection(object state)
{
var connection = (ConnectionInfo)state;
var buffer = new byte[BufferSize];
try
{
var bytesRead = connection.LocalSocket.Receive(buffer);
if (bytesRead < 1 || buffer[0] != Protocol.Socks4.Version)
{
connection.Terminate();
return;
}
OnLogMessage?.Invoke(this, $"Got {bytesRead} bytes from ");
}
catch (SocketException ex)
{
OnLogMessage?.Invoke(this, $"Caught SocketException in ProcessLocalConnection with error code {ex.SocketErrorCode}");
}
try
{
switch (buffer[1])
{
case Protocol.Socks4.CommandStreamConnection:
{
var portBuffer = new[] { buffer[2], buffer[3] };
var port = (ushort)(portBuffer[0] << 8 | portBuffer[1]);
var address = new[] { buffer[4], buffer[5], buffer[6], buffer[7] };
var destAddress = new IPAddress(address).ToString();
var destAddressFamily = AddressFamily.InterNetwork;
if (IsSocks4AProtocol(address))
{
var hostBuffer = new byte[256];
Buffer.BlockCopy(buffer, 9, hostBuffer, 0, 100);
// Resolve hostname, fallback to remote proxy dns resolution
var hostname = Encoding.ASCII.GetString(hostBuffer).TrimEnd((char)0);
if (!ResolveHostnamesRemotely)
{
var resolvedHostname = await DnsResolver.TryResolve(hostname);
if (resolvedHostname == null)
{
OnLogMessage?.Invoke(this, $"DNS resolution failed for {hostname}");
SendSocks4Reply(connection.LocalSocket, Protocol.Socks4.StatusRequestGranted, address, portBuffer);
connection.Terminate();
break;
}
destAddress = resolvedHostname.ToString();
destAddressFamily = resolvedHostname.AddressFamily;
}
else
{
destAddress = hostname;
destAddressFamily = AddressFamily.Unspecified;
}
}
connection.RemoteSocket = Socks5Client.Connect(
RemotEndPoint.Address.ToString(),
RemotEndPoint.Port,
destAddress,
port,
Username,
Password,
SendTimeout,
ReceiveTimeout);
OnRemoteConnect?.Invoke(this, new DnsEndPoint(destAddress, port, destAddressFamily));
if (connection.RemoteSocket.Connected)
{
OnLogMessage?.Invoke(this, "RelayBiDirectionally between server and client started");
SendSocks4Reply(connection.LocalSocket, Protocol.Socks4.StatusRequestGranted, address, portBuffer);
SocketRelay.RelayBiDirectionally(connection.RemoteSocket, connection.LocalSocket);
}
else
{
OnLogMessage?.Invoke(this, "RemoteSocket connection failed");
SendSocks4Reply(connection.LocalSocket, Protocol.Socks4.StatusRequestFailed, address, portBuffer);
connection.Terminate();
}
break;
}
case Protocol.Socks4.CommandBindingConnection:
{
var portBuffer = new[] { buffer[2], buffer[3] };
var address = new[] { buffer[4], buffer[5], buffer[6], buffer[7] };
// TCP/IP port binding not supported
SendSocks4Reply(connection.LocalSocket, Protocol.Socks4.StatusRequestFailed, address, portBuffer);
connection.Terminate();
break;
}
default:
OnLogMessage?.Invoke(this, "Unknown protocol on LocalSocket");
connection.Terminate();
break;
}
}
catch (SocketException ex)
{
OnLogMessage?.Invoke(this, $"Caught SocketException in ProcessLocalConnection with error code {ex.SocketErrorCode.ToString()}");
}
catch (Socks5Exception ex)
{
var portBuffer = new[] { buffer[2], buffer[3] };
var address = new[] { buffer[4], buffer[5], buffer[6], buffer[7] };
SendSocks4Reply(connection.LocalSocket, Protocol.Socks4.StatusRequestFailed, address, portBuffer);
connection.Terminate();
OnLogMessage?.Invoke(this, $"Caught Socks5Exception in ProcessLocalConnection with message {ex.Message}");
}
}
private void ProcessLocalConnection(object state)
{
var connection = (ConnectionInfo)state;
var buffer = new byte[BufferSize];
int bytesRead;
try
{
bytesRead = connection.LocalSocket.Receive(buffer);
if (bytesRead < 1 || buffer[0] != Protocol.Socks4.Version)
{
connection.LocalSocket.Close();
return;
}
OnLogMessage?.Invoke(this, $"LocalSocket.Receive {bytesRead}");
}
catch (SocketException ex)
{
OnLogMessage?.Invoke(this, $"Caught SocketException in ProcessLocalConnection with error code {ex.SocketErrorCode.ToString()}");
}
try
{
switch (buffer[1])
{
case Protocol.Socks4.CommandStreamConnection:
{
var portBuffer = new[] { buffer[2], buffer[3] };
var port = (ushort)(portBuffer[0] << 8 | portBuffer[1]);
var ipBuffer = new[] { buffer[4], buffer[5], buffer[6], buffer[7] };
var ip = new IPAddress(ipBuffer);
var destinationEndPoint = new IPEndPoint(ip, port);
if (IsSocks4AProtocol(ipBuffer))
{
var hostBuffer = new byte[256];
Buffer.BlockCopy(buffer, 9, hostBuffer, 0, 100);
// Resolve hostname, fallback to remote proxy dns resolution
var hostname = Encoding.ASCII.GetString(hostBuffer).TrimEnd((char)0);
var destinationIp = ResolveHostnamesRemotely ? null : DnsResolver.TryResolve(hostname);
connection.RemoteSocket = Socks5Client.Connect(
RemotEndPoint.Address.ToString(),
RemotEndPoint.Port, destinationIp == null ? hostname : destinationIp.ToString(),
port,
Username,
Password,
SendTimeout,
ReceiveTimeout
);
OnRemoteConnect?.Invoke(this, destinationEndPoint);
}
else
{
destinationEndPoint = new IPEndPoint(new IPAddress(ipBuffer), port);
connection.RemoteSocket = Socks5Client.Connect(
RemotEndPoint.Address.ToString(),
RemotEndPoint.Port,
destinationEndPoint.Address.ToString(),
port,
Username,
Password,
SendTimeout,
ReceiveTimeout
);
OnRemoteConnect?.Invoke(this, destinationEndPoint);
}
if (connection.RemoteSocket.Connected)
{
SendSocks4Reply(connection.LocalSocket, Protocol.Socks4.StatusRequestGranted, ipBuffer, portBuffer);
// Create the thread for the receives.
connection.RemoteThread = new Thread(ProcessRemoteConnection)
{
IsBackground = true
};
connection.RemoteThread.Start(connection);
}
else
{
OnLogMessage?.Invoke(this, "RemoteSocket connection failed");
SendSocks4Reply(connection.LocalSocket, Protocol.Socks4.StatusRequestFailed, ipBuffer, portBuffer);
connection.LocalSocket.Close();
}
break;
}
case Protocol.Socks4.CommandBindingConnection:
{
var portBuffer = new[] { buffer[2], buffer[3] };
var ipBuffer = new[] { buffer[4], buffer[5], buffer[6], buffer[7] };
// TCP/IP port binding not supported
SendSocks4Reply(connection.LocalSocket, Protocol.Socks4.StatusRequestFailed, ipBuffer, portBuffer);
connection.LocalSocket.Close();
break;
}
default:
OnLogMessage?.Invoke(this, "Unknown protocol on LocalSocket");
connection.LocalSocket.Close();
break;
}
// start receiving actual data if the socket still open
while (true)
{
if (!connection.LocalSocket.Connected || !connection.RemoteSocket.Connected)
{
break;
}
bytesRead = connection.LocalSocket.Receive(buffer);
if (bytesRead == 0)
{
break;
}
if (connection.RemoteSocket.Connected)
{
connection.RemoteSocket.Send(buffer, bytesRead, SocketFlags.None);
OnLogMessage?.Invoke(this, $"Forwarded {bytesRead} bytes from LocalSocket to RemoteSocket");
}
}
}
catch (SocketException ex)
{
OnLogMessage?.Invoke(this, $"Caught SocketException in ProcessLocalConnection with error code {ex.SocketErrorCode.ToString()}");
}
catch (Socks5Exception ex)
{
var portBuffer = new[] { buffer[2], buffer[3] };
var ipBuffer = new[] { buffer[4], buffer[5], buffer[6], buffer[7] };
SendSocks4Reply(connection.LocalSocket, Protocol.Socks4.StatusRequestFailed, ipBuffer, portBuffer);
connection.LocalSocket.Close();
OnLogMessage?.Invoke(this, $"Caught Socks5Exception in ProcessLocalConnection with message {ex.Message}");
}
if (connection.LocalSocket.Connected)
{
OnLogMessage?.Invoke(this, "Closing LocalSocket");
connection.LocalSocket.Close();
}
lock (_connections)
{
_connections.Remove(connection);
}
}
