func (c *UDPConn) writeUDPClient(dgram *gosocks5.UDPDatagram) error {
if c.udp != nil {
dgram.Header.Rsv = 0
buffer := bytes.Buffer{}
dgram.Write(&buffer)
_, err := c.udp.WriteTo(buffer.Bytes(), c.addr)
return err
}
dgram.Header.Rsv = uint16(len(dgram.Data))
return dgram.Write(c.tcp)
}
func (c *UDPConn) writeUDPServer(dgram *gosocks5.UDPDatagram) error {
if c.udp != nil {
addr, err := net.ResolveUDPAddr("udp", dgram.Header.Addr.String())
if err != nil {
glog.V(LWARNING).Infoln(err)
return nil // drop silently
}
_, err = c.udp.WriteTo(dgram.Data, addr)
return err
}
dgram.Header.Rsv = uint16(len(dgram.Data))
return dgram.Write(c.tcp)
}
func (s *Socks5Server) tunnelUDP(uc *net.UDPConn, cc net.Conn, client bool) (err error) {
errc := make(chan error, 2)
var clientAddr *net.UDPAddr
go func() {
b := make([]byte, LargeBufferSize)
for {
n, addr, err := uc.ReadFromUDP(b)
if err != nil {
errc <- err
return
}
var dgram *gosocks5.UDPDatagram
if client { // pipe from relay to tunnel
dgram, err = gosocks5.ReadUDPDatagram(bytes.NewReader(b[:n]))
if err != nil {
errc <- err
return
}
if clientAddr == nil {
clientAddr = addr
}
dgram.Header.Rsv = uint16(len(dgram.Data))
if err := dgram.Write(cc); err != nil {
errc <- err
return
}
glog.V(LDEBUG).Infof("[udp-tun] %s >>> %s length: %d", uc.LocalAddr(), dgram.Header.Addr, len(dgram.Data))
} else { // pipe from peer to tunnel
dgram = gosocks5.NewUDPDatagram(
gosocks5.NewUDPHeader(uint16(n), 0, ToSocksAddr(addr)), b[:n])
if err := dgram.Write(cc); err != nil {
errc <- err
return
}
glog.V(LDEBUG).Infof("[udp-tun] %s <<< %s length: %d", cc.RemoteAddr(), dgram.Header.Addr, len(dgram.Data))
}
}
}()
go func() {
for {
dgram, err := gosocks5.ReadUDPDatagram(cc)
if err != nil {
errc <- err
return
}
if client { // pipe from tunnel to relay
if clientAddr == nil {
continue
}
dgram.Header.Rsv = 0
buf := bytes.Buffer{}
dgram.Write(&buf)
if _, err := uc.WriteToUDP(buf.Bytes(), clientAddr); err != nil {
errc <- err
return
}
glog.V(LDEBUG).Infof("[udp-tun] %s <<< %s length: %d", uc.LocalAddr(), dgram.Header.Addr, len(dgram.Data))
} else { // pipe from tunnel to peer
addr, err := net.ResolveUDPAddr("udp", dgram.Header.Addr.String())
if err != nil {
continue // drop silently
}
if _, err := uc.WriteToUDP(dgram.Data, addr); err != nil {
errc <- err
return
}
glog.V(LDEBUG).Infof("[udp-tun] %s >>> %s length: %d", cc.RemoteAddr(), addr, len(dgram.Data))
}
}
}()
select {
case err = <-errc:
}
return
}