114 lines
4.0 KiB
C#
114 lines
4.0 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Text;
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using Shadowsocks.Encryption;
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using Shadowsocks.Model;
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using System.Net.Sockets;
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using System.Net;
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namespace Shadowsocks.Controller
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{
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class UDPRelay : Listener.Service
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{
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private Configuration _config;
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public UDPRelay(Configuration config)
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{
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this._config = config;
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}
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public bool Handle(byte[] firstPacket, int length, Socket socket, object state)
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{
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if (socket.ProtocolType != ProtocolType.Udp)
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{
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return false;
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}
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if (length < 4)
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{
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return false;
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}
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Listener.UDPState udpState = (Listener.UDPState)state;
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// TODO add cache
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UDPHandler handler = new UDPHandler(socket, _config.GetCurrentServer(), (IPEndPoint)udpState.remoteEndPoint);
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handler.Send(firstPacket, length);
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handler.Receive();
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return true;
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}
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class UDPHandler
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{
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private Socket _local;
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private Socket _remote;
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private Server _server;
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private byte[] _buffer = new byte[1500];
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private IPEndPoint _localEndPoint;
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private IPEndPoint _remoteEndPoint;
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public UDPHandler(Socket local, Server server, IPEndPoint localEndPoint)
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{
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// TODO add timeout
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_local = local;
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_server = server;
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_localEndPoint = localEndPoint;
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// TODO async resolving
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IPAddress ipAddress;
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bool parsed = IPAddress.TryParse(server.server, out ipAddress);
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if (!parsed)
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{
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IPHostEntry ipHostInfo = Dns.GetHostEntry(server.server);
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ipAddress = ipHostInfo.AddressList[0];
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}
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_remoteEndPoint = new IPEndPoint(ipAddress, server.server_port);
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_remote = new Socket(_remoteEndPoint.AddressFamily, SocketType.Dgram, ProtocolType.Udp);
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}
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public void Send(byte[] data, int length)
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{
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IEncryptor encryptor = EncryptorFactory.GetEncryptor(_server.method, _server.password);
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byte[] dataIn = new byte[length - 3];
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Array.Copy(data, 3, dataIn, 0, length - 3);
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byte[] dataOut = new byte[length - 3 + 16];
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int outlen;
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encryptor.Encrypt(dataIn, dataIn.Length, dataOut, out outlen);
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_remote.SendTo(dataOut, _remoteEndPoint);
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}
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public void Receive()
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{
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EndPoint remoteEndPoint = new IPEndPoint(IPAddress.Any, 0);
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_remote.BeginReceiveFrom(_buffer, 0, _buffer.Length, 0, ref remoteEndPoint, new AsyncCallback(RecvFromCallback), null);
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}
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public void RecvFromCallback(IAsyncResult ar)
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{
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try
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{
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EndPoint remoteEndPoint = new IPEndPoint(IPAddress.Any, 0);
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int bytesRead = _remote.EndReceiveFrom(ar, ref remoteEndPoint);
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byte[] dataOut = new byte[bytesRead];
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int outlen;
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IEncryptor encryptor = EncryptorFactory.GetEncryptor(_server.method, _server.password);
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encryptor.Decrypt(_buffer, bytesRead, dataOut, out outlen);
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byte[] sendBuf = new byte[outlen + 3];
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Array.Copy(dataOut, 0, sendBuf, 3, outlen);
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_local.SendTo(sendBuf, outlen + 3, 0, _localEndPoint);
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Receive();
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}
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catch (ObjectDisposedException)
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{
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}
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catch (Exception e)
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{
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}
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finally
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{
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}
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}
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}
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}
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}
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