public static void Handle(byte[] firstResponse, ProxyClient client)
{
if (!client.Controller.IsSocksSupported || !IsSocks(firstResponse))
{
client.Close();
return;
}
// Responding with socks protocol
byte clientVersion = firstResponse[0];
if (clientVersion == 5)
{
byte[] clientSupportedAuths = new byte[firstResponse[1]];
Array.Copy(firstResponse, 2, clientSupportedAuths, 0, firstResponse[1]);
byte[] serverResponse = new byte[2];
if (clientSupportedAuths.Length == 0)
{
client.Close(
"No authentication method found.",
null,
ErrorRenderer.HttpHeaderCode.C417ExpectationFailed);
return;
}
serverResponse[0] = clientVersion;
// -------------Selecting authentication type
byte serverSelectedAuth = 255;
foreach (byte item in clientSupportedAuths)
{
if (item == 0)
{
serverSelectedAuth = 0;
}
}
serverResponse[1] = serverSelectedAuth;
client.Write(serverResponse);
client.IsReceivingStarted = false;
// -------------Doing authentication
if (serverSelectedAuth == 255)
{
client.Close(
"SOCKS Connection only accept clients with no authentication information.",
null,
ErrorRenderer.HttpHeaderCode.C417ExpectationFailed);
return;
}
// -------------Establishing connection
byte[] response = new byte[client.UnderlyingSocket.ReceiveBufferSize];
client.UnderlyingSocket.ReceiveTimeout = client.NoDataTimeOut;
client.UnderlyingSocket.BeginReceive(
response,
0,
response.Length,
SocketFlags.None,
delegate(IAsyncResult ar)
{
try
{
int bytes = client.UnderlyingSocket.EndReceive(ar);
Array.Resize(ref response, bytes);
if (response == null || response.Length == 0)
{
client.Close(
"No request received. Connection Timeout.",
null,
ErrorRenderer.HttpHeaderCode.C417ExpectationFailed);
return;
}
if (response[0] != clientVersion)
{
client.Close(
"Unknown SOCKS version, Expected " + clientVersion,
null,
ErrorRenderer.HttpHeaderCode.C417ExpectationFailed);
return;
}
byte clientConnectionType = response[1];
byte clientAddressType = response[3];
string clientConnectionAddress = null;
byte[] clientUnformatedConnectionAddress;
ushort clientConnectionPort = 0;
byte serverAresponse = 0;
if (clientConnectionType != 1)
{
serverAresponse = 7;
}
switch (clientAddressType)
{
case 1:
clientUnformatedConnectionAddress = new byte[4];
Array.Copy(response, 4, clientUnformatedConnectionAddress, 0, 4);
clientConnectionAddress =
new IPAddress(clientUnformatedConnectionAddress).ToString();
clientConnectionPort = (ushort)((ushort)(response[8] * 256) + response[9]);
break;
case 3:
clientUnformatedConnectionAddress = new byte[response[4]];
Array.Copy(response, 5, clientUnformatedConnectionAddress, 0, response[4]);
clientConnectionAddress =
Encoding.ASCII.GetString(clientUnformatedConnectionAddress);
clientConnectionPort =
(ushort)
((ushort)(response[5 + response[4]] * 256) + response[5 + response[4] + 1]);
break;
case 4:
clientUnformatedConnectionAddress = new byte[16];
Array.Copy(response, 4, clientUnformatedConnectionAddress, 0, 16);
clientConnectionAddress =
new IPAddress(clientUnformatedConnectionAddress).ToString();
clientConnectionPort = (ushort)((ushort)(response[20] * 256) + response[21]);
break;
default:
serverAresponse = 8;
break;
}
serverResponse = new byte[3 + (response.Length - 3)];
serverResponse[0] = clientVersion;
serverResponse[1] = serverAresponse;
serverResponse[2] = 0;
serverResponse[3] = 3;
Array.Copy(response, 3, serverResponse, 3, response.Length - 3);
client.RequestAddress = "socks://" + clientConnectionAddress + ":"
+ clientConnectionPort;
client.Write(serverResponse);
client.IsReceivingStarted = false;
if (serverAresponse != 0)
{
client.Close(
"Response Error, Code: " + serverAresponse,
null,
ErrorRenderer.HttpHeaderCode.C417ExpectationFailed,
true);
return;
}
firstResponse = new byte[0];
DirectHandle(client, clientConnectionAddress, clientConnectionPort, firstResponse);
}
catch (Exception e)
{
client.Close(e.Message, e.StackTrace);
}
},
response);
}
else if (clientVersion == 4)
{
try
{
byte clientConnectionType = firstResponse[1];
byte serverAresponse = 90;
if (clientConnectionType != 1)
{
serverAresponse = 91;
}
ushort clientConnectionPort = (ushort)((ushort)(firstResponse[2] * 256) + firstResponse[3]);
byte[] clientUnformatedConnectionAddress = new byte[4];
Array.Copy(firstResponse, 4, clientUnformatedConnectionAddress, 0, 4);
string clientConnectionAddress = new IPAddress(clientUnformatedConnectionAddress).ToString();
if (clientConnectionAddress.StartsWith("0.0.0.") && !clientConnectionAddress.EndsWith(".0"))
{
int domainStart = 0, domainEnd = 0;
for (int i = 8; i < firstResponse.Length; i++)
{
if (firstResponse[i] == 0)
{
if (domainStart == 0)
{
domainStart = i + 1;
}
else if (domainEnd == 0)
{
domainEnd = i;
}
}
}
if (domainEnd != 0 && domainStart != 0)
{
clientConnectionAddress = Encoding.ASCII.GetString(
firstResponse,
domainStart,
domainEnd - domainStart);
}
else
{
serverAresponse = 91;
}
}
byte[] serverResponse = new byte[8];
serverResponse[0] = 0;
serverResponse[1] = serverAresponse;
Array.Copy(firstResponse, 2, serverResponse, 2, 2); // PORT
Array.Copy(firstResponse, 4, serverResponse, 4, 4); // IP
client.RequestAddress = "socks://" + clientConnectionAddress + ":" + clientConnectionPort;
client.Write(serverResponse);
client.IsReceivingStarted = false;
if (serverAresponse != 90)
{
client.Close(
"Response Error, Code: " + serverAresponse,
null,
ErrorRenderer.HttpHeaderCode.C417ExpectationFailed,
true);
return;
}
firstResponse = new byte[0];
DirectHandle(client, clientConnectionAddress, clientConnectionPort, firstResponse);
}
catch (Exception e)
{
client.Close(e.Message, e.StackTrace);
}
}
}