private bool HandleSocks4(Socket socket, IChannelDirectTcpip channel, TimeSpan timeout)
{
var commandCode = SocketAbstraction.ReadByte(socket, timeout);
if (commandCode == -1)
{
// 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 = Pack.BigEndianToUInt16(portBuffer);
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);
}
public void BigEndianToUInt16()
{
Assert.AreEqual(0, Pack.BigEndianToUInt16(new byte[] { 0, 0 }));
Assert.AreEqual(1, Pack.BigEndianToUInt16(new byte[] { 0, 1 }));
Assert.AreEqual(256, Pack.BigEndianToUInt16(new byte[] { 1, 0 }));
Assert.AreEqual(257, Pack.BigEndianToUInt16(new byte[] { 1, 1 }));
Assert.AreEqual(1025, Pack.BigEndianToUInt16(new byte[] { 4, 1 }));
Assert.AreEqual(ushort.MaxValue, Pack.BigEndianToUInt16(new byte[] { 255, 255 }));
}
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);
}