Method embedHandleAssociate

pkg/socks5/server.go:343–422

(req *request, udpConn net.PacketConn)

}

func (s *Server) embedHandleAssociate(req *request, udpConn net.PacketConn) error {
	defer func() {
		_ = udpConn.Close()
	}()

	go func() {
		var buf [1]byte
		for {
			_, err := req.Conn.Read(buf[:])
			if err != nil {
				_ = udpConn.Close()
				break
			}
		}
	}()

	var (
		sourceAddr  net.Addr
		wantSource  string
		targetAddr  net.Addr
		wantTarget  string
		replyPrefix []byte
		buf         [maxUdpPacket]byte
	)

	for {
		n, addr, err := udpConn.ReadFrom(buf[:])
		if err != nil {
			return err
		}

		if sourceAddr == nil {
			sourceAddr = addr
			wantSource = sourceAddr.String()
		}

		gotAddr := addr.String()
		if wantSource == gotAddr {
			if n < 3 {
				continue
			}
			reader := bytes.NewBuffer(buf[3:n])
			addr, err := readAddr(reader)
			if err != nil {
				s.Logger.Debug(err)
				continue
			}
			if targetAddr == nil {
				targetAddr = &net.UDPAddr{
					IP:   addr.IP,
					Port: addr.Port,
				}
				wantTarget = targetAddr.String()
			}
			if addr.String() != wantTarget {
				s.Logger.Debug(fmt.Errorf("ignore non-target addresses %s", addr))
				continue
			}