Example #1
0
func (ut *udpConnTrack) run() {
	// connect to socks
	var e error
	for i := 0; i < 2; i++ {
		ut.socksConn, e = dialLocalSocks(ut.localSocksAddr)
		if e != nil {
			log.Printf("fail to connect SOCKS proxy: %s", e)
		} else {
			// need to finish handshake in 1 mins
			ut.socksConn.SetDeadline(time.Now().Add(time.Minute * 1))
			break
		}
	}
	if ut.socksConn == nil {
		close(ut.socksClosed)
		close(ut.quitBySelf)
		ut.t2s.clearUDPConnTrack(ut.id)
		return
	}

	// create one UDP to recv/send packets
	socksAddr := ut.socksConn.LocalAddr().(*net.TCPAddr)
	udpBind, err := net.ListenUDP("udp", &net.UDPAddr{
		IP:   socksAddr.IP,
		Port: 0,
		Zone: socksAddr.Zone,
	})
	if err != nil {
		log.Printf("error in binding local UDP: %s", err)
		ut.socksConn.Close()
		close(ut.socksClosed)
		close(ut.quitBySelf)
		ut.t2s.clearUDPConnTrack(ut.id)
		return
	}

	// socks request/reply
	_, e = gosocks.WriteSocksRequest(ut.socksConn, &gosocks.SocksRequest{
		Cmd:      gosocks.SocksCmdUDPAssociate,
		HostType: gosocks.SocksIPv4Host,
		DstHost:  "0.0.0.0",
		DstPort:  0,
	})
	if e != nil {
		log.Printf("error to send socks request: %s", e)
		ut.socksConn.Close()
		close(ut.socksClosed)
		close(ut.quitBySelf)
		ut.t2s.clearUDPConnTrack(ut.id)
		return
	}
	reply, e := gosocks.ReadSocksReply(ut.socksConn)
	if e != nil {
		log.Printf("error to read socks reply: %s", e)
		ut.socksConn.Close()
		close(ut.socksClosed)
		close(ut.quitBySelf)
		ut.t2s.clearUDPConnTrack(ut.id)
		return
	}
	if reply.Rep != gosocks.SocksSucceeded {
		log.Printf("socks connect request fail, retcode: %d", reply.Rep)
		ut.socksConn.Close()
		close(ut.socksClosed)
		close(ut.quitBySelf)
		ut.t2s.clearUDPConnTrack(ut.id)
		return
	}
	relayAddr := gosocks.SocksAddrToNetAddr("udp", reply.BndHost, reply.BndPort).(*net.UDPAddr)

	ut.socksConn.SetDeadline(time.Time{})
	// monitor socks TCP connection
	go gosocks.ConnMonitor(ut.socksConn, ut.socksClosed)
	// read UDP packets from relay
	quitUDP := make(chan bool)
	chRelayUDP := make(chan *gosocks.UDPPacket)
	go gosocks.UDPReader(udpBind, chRelayUDP, quitUDP)

	for {
		var t *time.Timer
		if ut.t2s.isDNS(ut.remoteIP.String(), ut.remotePort) {
			t = time.NewTimer(10 * time.Second)
		} else {
			t = time.NewTimer(2 * time.Minute)
		}
		select {
		// pkt from relay
		case pkt, ok := <-chRelayUDP:
			if !ok {
				ut.socksConn.Close()
				udpBind.Close()
				close(ut.quitBySelf)
				ut.t2s.clearUDPConnTrack(ut.id)
				close(quitUDP)
				return
			}
			if pkt.Addr.String() != relayAddr.String() {
				continue
			}
			udpReq, err := gosocks.ParseUDPRequest(pkt.Data)
			if err != nil {
				log.Printf("error to parse UDP request from relay: %s", err)
				continue
			}
			if udpReq.Frag != gosocks.SocksNoFragment {
				continue
			}
			ut.send(udpReq.Data)
			if ut.t2s.isDNS(ut.remoteIP.String(), ut.remotePort) {
				// DNS-without-fragment only has one request-response
				log.Printf("DNS session")
				if ut.t2s.cache != nil {
					ut.t2s.cache.store(udpReq.Data)
				}
				ut.socksConn.Close()
				udpBind.Close()
				close(ut.quitBySelf)
				ut.t2s.clearUDPConnTrack(ut.id)
				close(quitUDP)
				return
			}

		// pkt from tun
		case pkt := <-ut.fromTunCh:
			req := &gosocks.UDPRequest{
				Frag:     0,
				HostType: gosocks.SocksIPv4Host,
				DstHost:  pkt.ip.DstIP.String(),
				DstPort:  uint16(pkt.udp.DstPort),
				Data:     pkt.udp.Payload,
			}
			datagram := gosocks.PackUDPRequest(req)
			_, err := udpBind.WriteToUDP(datagram, relayAddr)
			releaseUDPPacket(pkt)
			if err != nil {
				log.Printf("error to send UDP packet to relay: %s", err)
				ut.socksConn.Close()
				udpBind.Close()
				close(ut.quitBySelf)
				ut.t2s.clearUDPConnTrack(ut.id)
				close(quitUDP)
				return
			}

		case <-ut.socksClosed:
			ut.socksConn.Close()
			udpBind.Close()
			close(ut.quitBySelf)
			ut.t2s.clearUDPConnTrack(ut.id)
			close(quitUDP)
			return

		case <-t.C:
			ut.socksConn.Close()
			udpBind.Close()
			close(ut.quitBySelf)
			ut.t2s.clearUDPConnTrack(ut.id)
			close(quitUDP)
			return

		case <-ut.quitByOther:
			log.Printf("udpConnTrack quitByOther")
			ut.socksConn.Close()
			udpBind.Close()
			close(quitUDP)
			return
		}
		t.Stop()
	}
}
Example #2
0
func (tt *tcpConnTrack) tcpSocks2Tun(dstIP net.IP, dstPort uint16, conn net.Conn, readCh chan<- []byte, writeCh <-chan *tcpPacket, closeCh chan bool) {
	_, e := gosocks.WriteSocksRequest(conn, &gosocks.SocksRequest{
		Cmd:      gosocks.SocksCmdConnect,
		HostType: gosocks.SocksIPv4Host,
		DstHost:  dstIP.String(),
		DstPort:  dstPort,
	})
	if e != nil {
		log.Printf("error to send socks request: %s", e)
		conn.Close()
		close(closeCh)
		return
	}
	reply, e := gosocks.ReadSocksReply(conn)
	if e != nil {
		log.Printf("error to read socks reply: %s", e)
		conn.Close()
		close(closeCh)
		return
	}
	if reply.Rep != gosocks.SocksSucceeded {
		log.Printf("socks connect request fail, retcode: %d", reply.Rep)
		conn.Close()
		close(closeCh)
		return
	}
	// writer
	go func() {
	loop:
		for {
			select {
			case <-closeCh:
				break loop
			case pkt := <-writeCh:
				conn.Write(pkt.tcp.Payload)

				// increase window when processed
				wnd := atomic.LoadInt32(&tt.recvWindow)
				wnd += int32(len(pkt.tcp.Payload))
				if wnd > int32(MAX_RECV_WINDOW) {
					wnd = int32(MAX_RECV_WINDOW)
				}
				atomic.StoreInt32(&tt.recvWindow, wnd)

				releaseTCPPacket(pkt)
			}
		}
	}()

	// reader
	for {
		var buf [MTU - 40]byte

		// tt.sendWndCond.L.Lock()
		var wnd int32
		var cur int32
		wnd = atomic.LoadInt32(&tt.sendWindow)

		if wnd <= 0 {
			for wnd <= 0 {
				tt.sendWndCond.L.Lock()
				tt.sendWndCond.Wait()
				wnd = atomic.LoadInt32(&tt.sendWindow)
			}
			tt.sendWndCond.L.Unlock()
		}

		cur = wnd
		if cur > MTU-40 {
			cur = MTU - 40
		}
		// tt.sendWndCond.L.Unlock()

		n, e := conn.Read(buf[:cur])
		if e != nil {
			log.Printf("error to read from socks: %s", e)
			conn.Close()
			break
		} else {
			b := make([]byte, n)
			copy(b, buf[:n])
			readCh <- b

			// tt.sendWndCond.L.Lock()
			nxt := wnd - int32(n)
			if nxt < 0 {
				nxt = 0
			}
			// if sendWindow does not equal to wnd, it is already updated by a
			// received pkt from TUN
			atomic.CompareAndSwapInt32(&tt.sendWindow, wnd, nxt)
			// tt.sendWndCond.L.Unlock()
		}
	}
	close(closeCh)
}