private bool HandleSocks4(Socket socket, IChannelDirectTcpip channel, TimeSpan timeout)
{
var commandCode = SocketAbstraction.ReadByte(socket, timeout);
if (commandCode == 0)
{
// SOCKS client closed connection
return(false);
}
// TODO: See what need to be done depends on the code
var portBuffer = new byte[2];
if (SocketAbstraction.Read(socket, portBuffer, 0, portBuffer.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
var port = (uint)(portBuffer[0] * 256 + portBuffer[1]);
var ipBuffer = new byte[4];
if (SocketAbstraction.Read(socket, ipBuffer, 0, ipBuffer.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
var ipAddress = new IPAddress(ipBuffer);
var username = ReadString(socket, timeout);
if (username == null)
{
// SOCKS client closed connection
return(false);
}
var host = ipAddress.ToString();
RaiseRequestReceived(host, port);
channel.Open(host, port, this, socket);
SocketAbstraction.SendByte(socket, 0x00);
if (channel.IsOpen)
{
SocketAbstraction.SendByte(socket, 0x5a);
SocketAbstraction.Send(socket, portBuffer, 0, portBuffer.Length);
SocketAbstraction.Send(socket, ipBuffer, 0, ipBuffer.Length);
return(true);
}
// signal that request was rejected or failed
SocketAbstraction.SendByte(socket, 0x5b);
return(false);
}
private static string GetSocks5Host(int addressType, Socket socket, TimeSpan timeout)
{
switch (addressType)
{
case 0x01: // IPv4
{
var addressBuffer = new byte[4];
if (SocketAbstraction.Read(socket, addressBuffer, 0, 4, timeout) == 0)
{
// SOCKS client closed connection
return(null);
}
var ipv4 = new IPAddress(addressBuffer);
return(ipv4.ToString());
}
case 0x03: // Domain name
{
var length = SocketAbstraction.ReadByte(socket, timeout);
if (length == -1)
{
// SOCKS client closed connection
return(null);
}
var addressBuffer = new byte[length];
if (SocketAbstraction.Read(socket, addressBuffer, 0, addressBuffer.Length, timeout) == 0)
{
// SOCKS client closed connection
return(null);
}
var hostName = SshData.Ascii.GetString(addressBuffer, 0, addressBuffer.Length);
return(hostName);
}
case 0x04: // IPv6
{
var addressBuffer = new byte[16];
if (SocketAbstraction.Read(socket, addressBuffer, 0, 16, timeout) == 0)
{
// SOCKS client closed connection
return(null);
}
var ipv6 = new IPAddress(addressBuffer);
return(ipv6.ToString());
}
default:
throw new ProxyException(string.Format("SOCKS5: Address type '{0}' is not supported.", addressType));
}
}
private bool HandleSocks(IChannelDirectTcpip channel, Socket remoteSocket, TimeSpan timeout)
{
// create eventhandler which is to be invoked to interrupt a blocking receive
// when we're closing the forwarded port
EventHandler closeClientSocket = (_, args) => CloseSocket(remoteSocket);
Closing += closeClientSocket;
try
{
#if DEBUG_GERT
Console.WriteLine("ID: " + Thread.CurrentThread.ManagedThreadId + " | Before ReadByte for version | " + DateTime.Now.ToString("hh:mm:ss.fff"));
#endif // DEBUG_GERT
var version = SocketAbstraction.ReadByte(remoteSocket, timeout);
if (version == -1)
{
return(false);
}
#if DEBUG_GERT
Console.WriteLine("ID: " + Thread.CurrentThread.ManagedThreadId + " | After ReadByte for version | " + DateTime.Now.ToString("hh:mm:ss.fff"));
#endif // DEBUG_GERT
if (version == 4)
{
return(HandleSocks4(remoteSocket, channel, timeout));
}
else if (version == 5)
{
return(HandleSocks5(remoteSocket, channel, timeout));
}
else
{
throw new NotSupportedException(string.Format("SOCKS version {0} is not supported.", version));
}
}
finally
{
// interrupt of blocking receive is now handled by channel (SOCKS4 and SOCKS5)
// or no longer necessary
Closing -= closeClientSocket;
}
}
private bool HandleSocks(IChannelDirectTcpip channel, Socket clientSocket, TimeSpan timeout)
{
// create eventhandler which is to be invoked to interrupt a blocking receive
// when we're closing the forwarded port
EventHandler closeClientSocket = (_, args) => CloseClientSocket(clientSocket);
Closing += closeClientSocket;
try
{
var version = SocketAbstraction.ReadByte(clientSocket, timeout);
switch (version)
{
case -1:
// SOCKS client closed connection
return(false);
case 4:
return(HandleSocks4(clientSocket, channel, timeout));
case 5:
return(HandleSocks5(clientSocket, channel, timeout));
default:
throw new NotSupportedException(string.Format("SOCKS version {0} is not supported.", version));
}
}
catch (SocketException ex)
{
// ignore exception thrown by interrupting the blocking receive as part of closing
// the forwarded port
if (ex.SocketErrorCode != SocketError.Interrupted)
{
RaiseExceptionEvent(ex);
}
return(false);
}
finally
{
// interrupt of blocking receive is now handled by channel (SOCKS4 and SOCKS5)
// or no longer necessary
Closing -= closeClientSocket;
}
}
private bool HandleSocks5(Socket socket, IChannelDirectTcpip channel, TimeSpan timeout)
{
#if DEBUG_GERT
Console.WriteLine("ID: " + Thread.CurrentThread.ManagedThreadId + " | Handling Socks5: " + socket.LocalEndPoint + " | " + socket.RemoteEndPoint + " | " + DateTime.Now.ToString("hh:mm:ss.fff"));
#endif // DEBUG_GERT
var authenticationMethodsCount = SocketAbstraction.ReadByte(socket, timeout);
if (authenticationMethodsCount == -1)
{
// SOCKS client closed connection
return(false);
}
#if DEBUG_GERT
Console.WriteLine("ID: " + Thread.CurrentThread.ManagedThreadId + " | After ReadByte for authenticationMethodsCount | " + DateTime.Now.ToString("hh:mm:ss.fff"));
#endif // DEBUG_GERT
var authenticationMethods = new byte[authenticationMethodsCount];
if (SocketAbstraction.Read(socket, authenticationMethods, 0, authenticationMethods.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
#if DEBUG_GERT
Console.WriteLine("ID: " + Thread.CurrentThread.ManagedThreadId + " | After Read for authenticationMethods | " + DateTime.Now.ToString("hh:mm:ss.fff"));
#endif // DEBUG_GERT
if (authenticationMethods.Min() == 0)
{
// no user authentication is one of the authentication methods supported
// by the SOCKS client
SocketAbstraction.Send(socket, new byte[] { 0x05, 0x00 }, 0, 2);
#if DEBUG_GERT
Console.WriteLine("ID: " + Thread.CurrentThread.ManagedThreadId + " | After Send for authenticationMethods 0 | " + DateTime.Now.ToString("hh:mm:ss.fff"));
#endif // DEBUG_GERT
}
else
{
// the SOCKS client requires authentication, which we currently do not support
SocketAbstraction.Send(socket, new byte[] { 0x05, 0xFF }, 0, 2);
// we continue business as usual but expect the client to close the connection
// so one of the subsequent reads should return -1 signaling that the client
// has effectively closed the connection
#if DEBUG_GERT
Console.WriteLine("ID: " + Thread.CurrentThread.ManagedThreadId + " | After Send for authenticationMethods 2 | " + DateTime.Now.ToString("hh:mm:ss.fff"));
#endif // DEBUG_GERT
}
var version = SocketAbstraction.ReadByte(socket, timeout);
if (version == -1)
{
// SOCKS client closed connection
return(false);
}
if (version != 5)
{
throw new ProxyException("SOCKS5: Version 5 is expected.");
}
var commandCode = SocketAbstraction.ReadByte(socket, timeout);
if (commandCode == -1)
{
// SOCKS client closed connection
return(false);
}
var reserved = SocketAbstraction.ReadByte(socket, timeout);
if (reserved == -1)
{
// SOCKS client closed connection
return(false);
}
if (reserved != 0)
{
throw new ProxyException("SOCKS5: 0 is expected for reserved byte.");
}
var addressType = SocketAbstraction.ReadByte(socket, timeout);
if (addressType == -1)
{
// SOCKS client closed connection
return(false);
}
IPAddress ipAddress;
byte[] addressBuffer;
switch (addressType)
{
case 0x01:
{
addressBuffer = new byte[4];
if (SocketAbstraction.Read(socket, addressBuffer, 0, 4, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
ipAddress = new IPAddress(addressBuffer);
}
break;
case 0x03:
{
var length = SocketAbstraction.ReadByte(socket, timeout);
addressBuffer = new byte[length];
if (SocketAbstraction.Read(socket, addressBuffer, 0, addressBuffer.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
ipAddress = IPAddress.Parse(SshData.Ascii.GetString(addressBuffer));
//var hostName = new Common.ASCIIEncoding().GetString(addressBuffer);
//ipAddress = Dns.GetHostEntry(hostName).AddressList[0];
}
break;
case 0x04:
{
addressBuffer = new byte[16];
if (SocketAbstraction.Read(socket, addressBuffer, 0, 16, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
ipAddress = new IPAddress(addressBuffer);
}
break;
default:
throw new ProxyException(string.Format("SOCKS5: Address type '{0}' is not supported.", addressType));
}
var portBuffer = new byte[2];
if (SocketAbstraction.Read(socket, portBuffer, 0, portBuffer.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
var port = (uint)(portBuffer[0] * 256 + portBuffer[1]);
var host = ipAddress.ToString();
RaiseRequestReceived(host, port);
#if DEBUG_GERT
Console.WriteLine("ID: " + Thread.CurrentThread.ManagedThreadId + " | Before channel open | " + DateTime.Now.ToString("hh:mm:ss.fff"));
var stopWatch = new Stopwatch();
stopWatch.Start();
#endif // DEBUG_GERT
channel.Open(host, port, this, socket);
#if DEBUG_GERT
stopWatch.Stop();
Console.WriteLine("ID: " + Thread.CurrentThread.ManagedThreadId + " | After channel open | " + DateTime.Now.ToString("hh:mm:ss.fff") + " => " + stopWatch.ElapsedMilliseconds);
#endif // DEBUG_GERT
SocketAbstraction.SendByte(socket, 0x05);
if (channel.IsOpen)
{
SocketAbstraction.SendByte(socket, 0x00);
}
else
{
SocketAbstraction.SendByte(socket, 0x01);
}
// reserved
SocketAbstraction.SendByte(socket, 0x00);
if (ipAddress.AddressFamily == AddressFamily.InterNetwork)
{
SocketAbstraction.SendByte(socket, 0x01);
}
else if (ipAddress.AddressFamily == AddressFamily.InterNetworkV6)
{
SocketAbstraction.SendByte(socket, 0x04);
}
else
{
throw new NotSupportedException("Not supported address family.");
}
var addressBytes = ipAddress.GetAddressBytes();
SocketAbstraction.Send(socket, addressBytes, 0, addressBytes.Length);
SocketAbstraction.Send(socket, portBuffer, 0, portBuffer.Length);
return(true);
}
private bool HandleSocks5(Socket socket, IChannelDirectTcpip channel, TimeSpan timeout)
{
var authenticationMethodsCount = SocketAbstraction.ReadByte(socket, timeout);
if (authenticationMethodsCount == -1)
{
// SOCKS client closed connection
return(false);
}
var authenticationMethods = new byte[authenticationMethodsCount];
if (SocketAbstraction.Read(socket, authenticationMethods, 0, authenticationMethods.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
if (authenticationMethods.Min() == 0)
{
// no user authentication is one of the authentication methods supported
// by the SOCKS client
SocketAbstraction.Send(socket, new byte[] { 0x05, 0x00 }, 0, 2);
}
else
{
// the SOCKS client requires authentication, which we currently do not support
SocketAbstraction.Send(socket, new byte[] { 0x05, 0xFF }, 0, 2);
// we continue business as usual but expect the client to close the connection
// so one of the subsequent reads should return -1 signaling that the client
// has effectively closed the connection
}
var version = SocketAbstraction.ReadByte(socket, timeout);
if (version == -1)
{
// SOCKS client closed connection
return(false);
}
if (version != 5)
{
throw new ProxyException("SOCKS5: Version 5 is expected.");
}
var commandCode = SocketAbstraction.ReadByte(socket, timeout);
if (commandCode == -1)
{
// SOCKS client closed connection
return(false);
}
var reserved = SocketAbstraction.ReadByte(socket, timeout);
if (reserved == -1)
{
// SOCKS client closed connection
return(false);
}
if (reserved != 0)
{
throw new ProxyException("SOCKS5: 0 is expected for reserved byte.");
}
var addressType = SocketAbstraction.ReadByte(socket, timeout);
if (addressType == -1)
{
// SOCKS client closed connection
return(false);
}
IPAddress ipAddress;
byte[] addressBuffer;
switch (addressType)
{
case 0x01:
{
addressBuffer = new byte[4];
if (SocketAbstraction.Read(socket, addressBuffer, 0, 4, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
ipAddress = new IPAddress(addressBuffer);
}
break;
case 0x03:
{
var length = SocketAbstraction.ReadByte(socket, timeout);
if (length == -1)
{
// SOCKS client closed connection
return(false);
}
addressBuffer = new byte[length];
if (SocketAbstraction.Read(socket, addressBuffer, 0, addressBuffer.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
ipAddress = IPAddress.Parse(SshData.Ascii.GetString(addressBuffer, 0, addressBuffer.Length));
//var hostName = new Common.ASCIIEncoding().GetString(addressBuffer);
//ipAddress = Dns.GetHostEntry(hostName).AddressList[0];
}
break;
case 0x04:
{
addressBuffer = new byte[16];
if (SocketAbstraction.Read(socket, addressBuffer, 0, 16, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
ipAddress = new IPAddress(addressBuffer);
}
break;
default:
throw new ProxyException(string.Format("SOCKS5: Address type '{0}' is not supported.", addressType));
}
var portBuffer = new byte[2];
if (SocketAbstraction.Read(socket, portBuffer, 0, portBuffer.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
var port = (uint)(portBuffer[0] * 256 + portBuffer[1]);
var host = ipAddress.ToString();
RaiseRequestReceived(host, port);
channel.Open(host, port, this, socket);
SocketAbstraction.SendByte(socket, 0x05);
if (channel.IsOpen)
{
SocketAbstraction.SendByte(socket, 0x00);
}
else
{
SocketAbstraction.SendByte(socket, 0x01);
}
// reserved
SocketAbstraction.SendByte(socket, 0x00);
if (ipAddress.AddressFamily == AddressFamily.InterNetwork)
{
SocketAbstraction.SendByte(socket, 0x01);
}
else if (ipAddress.AddressFamily == AddressFamily.InterNetworkV6)
{
SocketAbstraction.SendByte(socket, 0x04);
}
else
{
throw new NotSupportedException("Not supported address family.");
}
var addressBytes = ipAddress.GetAddressBytes();
SocketAbstraction.Send(socket, addressBytes, 0, addressBytes.Length);
SocketAbstraction.Send(socket, portBuffer, 0, portBuffer.Length);
return(true);
}
private bool HandleSocks5(Socket socket, IChannelDirectTcpip channel, TimeSpan timeout)
{
var authenticationMethodsCount = SocketAbstraction.ReadByte(socket, timeout);
if (authenticationMethodsCount == -1)
{
// SOCKS client closed connection
return(false);
}
var authenticationMethods = new byte[authenticationMethodsCount];
if (SocketAbstraction.Read(socket, authenticationMethods, 0, authenticationMethods.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
if (authenticationMethods.Min() == 0)
{
// no user authentication is one of the authentication methods supported
// by the SOCKS client
SocketAbstraction.Send(socket, new byte[] { 0x05, 0x00 }, 0, 2);
}
else
{
// the SOCKS client requires authentication, which we currently do not support
SocketAbstraction.Send(socket, new byte[] { 0x05, 0xFF }, 0, 2);
// we continue business as usual but expect the client to close the connection
// so one of the subsequent reads should return -1 signaling that the client
// has effectively closed the connection
}
var version = SocketAbstraction.ReadByte(socket, timeout);
if (version == -1)
{
// SOCKS client closed connection
return(false);
}
if (version != 5)
{
throw new ProxyException("SOCKS5: Version 5 is expected.");
}
var commandCode = SocketAbstraction.ReadByte(socket, timeout);
if (commandCode == -1)
{
// SOCKS client closed connection
return(false);
}
var reserved = SocketAbstraction.ReadByte(socket, timeout);
if (reserved == -1)
{
// SOCKS client closed connection
return(false);
}
if (reserved != 0)
{
throw new ProxyException("SOCKS5: 0 is expected for reserved byte.");
}
var addressType = SocketAbstraction.ReadByte(socket, timeout);
if (addressType == -1)
{
// SOCKS client closed connection
return(false);
}
var host = GetSocks5Host(addressType, socket, timeout);
if (host == null)
{
// SOCKS client closed connection
return(false);
}
var portBuffer = new byte[2];
if (SocketAbstraction.Read(socket, portBuffer, 0, portBuffer.Length, timeout) == 0)
{
// SOCKS client closed connection
return(false);
}
var port = Pack.BigEndianToUInt16(portBuffer);
RaiseRequestReceived(host, port);
channel.Open(host, port, this, socket);
var socksReply = CreateSocks5Reply(channel.IsOpen);
SocketAbstraction.Send(socket, socksReply, 0, socksReply.Length);
return(true);
}
