package tunnel import ( "errors" "io" "net" "time" N "github.com/Dreamacro/clash/common/net" "github.com/Dreamacro/clash/common/pool" "github.com/Dreamacro/clash/component/resolver" C "github.com/Dreamacro/clash/constant" ) func handleUDPToRemote(packet C.UDPPacket, pc C.PacketConn, metadata *C.Metadata) error { defer packet.Drop() // local resolve UDP dns if !metadata.Resolved() { ip, err := resolver.ResolveIP(metadata.Host) if err != nil { return err } metadata.DstIP = ip } addr := metadata.UDPAddr() if addr == nil { return errors.New("udp addr invalid") } if _, err := pc.WriteTo(packet.Data(), addr); err != nil { return err } // reset timeout pc.SetReadDeadline(time.Now().Add(udpTimeout)) return nil } func handleUDPToLocal(packet C.UDPPacket, pc net.PacketConn, key string, fAddr net.Addr) { buf := pool.Get(pool.RelayBufferSize) defer pool.Put(buf) defer natTable.Delete(key) defer pc.Close() for { pc.SetReadDeadline(time.Now().Add(udpTimeout)) n, from, err := pc.ReadFrom(buf) if err != nil { return } if fAddr != nil { from = fAddr } _, err = packet.WriteBack(buf[:n], from) if err != nil { return } } } func handleSocket(ctx C.ConnContext, outbound net.Conn) { relay(ctx.Conn(), outbound) } // relay copies between left and right bidirectionally. func relay(leftConn, rightConn net.Conn) { ch := make(chan error) go func() { buf := pool.Get(pool.RelayBufferSize) // Wrapping to avoid using *net.TCPConn.(ReadFrom) // See also https://github.com/Dreamacro/clash/pull/1209 _, err := io.CopyBuffer(N.WriteOnlyWriter{Writer: leftConn}, N.ReadOnlyReader{Reader: rightConn}, buf) pool.Put(buf) leftConn.SetReadDeadline(time.Now()) ch <- err }() buf := pool.Get(pool.RelayBufferSize) io.CopyBuffer(N.WriteOnlyWriter{Writer: rightConn}, N.ReadOnlyReader{Reader: leftConn}, buf) pool.Put(buf) rightConn.SetReadDeadline(time.Now()) <-ch }