package upnp import ( "fmt" "net" "time" "github.com/tendermint/tendermint/libs/log" ) type Capabilities struct { PortMapping bool Hairpin bool } func makeUPNPListener(intPort int, extPort int, logger log.Logger) (NAT, net.Listener, net.IP, error) { nat, err := Discover() if err != nil { return nil, nil, nil, fmt.Errorf("nat upnp could not be discovered: %v", err) } logger.Info(fmt.Sprintf("ourIP: %v", nat.(*upnpNAT).ourIP)) ext, err := nat.GetExternalAddress() if err != nil { return nat, nil, nil, fmt.Errorf("external address error: %v", err) } logger.Info(fmt.Sprintf("External address: %v", ext)) port, err := nat.AddPortMapping("tcp", extPort, intPort, "Tendermint UPnP Probe", 0) if err != nil { return nat, nil, ext, fmt.Errorf("port mapping error: %v", err) } logger.Info(fmt.Sprintf("Port mapping mapped: %v", port)) // also run the listener, open for all remote addresses. listener, err := net.Listen("tcp", fmt.Sprintf(":%v", intPort)) if err != nil { return nat, nil, ext, fmt.Errorf("error establishing listener: %v", err) } return nat, listener, ext, nil } func testHairpin(listener net.Listener, extAddr string, logger log.Logger) (supportsHairpin bool) { // Listener go func() { inConn, err := listener.Accept() if err != nil { logger.Info(fmt.Sprintf("Listener.Accept() error: %v", err)) return } logger.Info(fmt.Sprintf("Accepted incoming connection: %v -> %v", inConn.LocalAddr(), inConn.RemoteAddr())) buf := make([]byte, 1024) n, err := inConn.Read(buf) if err != nil { logger.Info(fmt.Sprintf("Incoming connection read error: %v", err)) return } logger.Info(fmt.Sprintf("Incoming connection read %v bytes: %X", n, buf)) if string(buf) == "test data" { supportsHairpin = true return } }() // Establish outgoing outConn, err := net.Dial("tcp", extAddr) if err != nil { logger.Info(fmt.Sprintf("Outgoing connection dial error: %v", err)) return } n, err := outConn.Write([]byte("test data")) if err != nil { logger.Info(fmt.Sprintf("Outgoing connection write error: %v", err)) return } logger.Info(fmt.Sprintf("Outgoing connection wrote %v bytes", n)) // Wait for data receipt time.Sleep(1 * time.Second) return supportsHairpin } func Probe(logger log.Logger) (caps Capabilities, err error) { logger.Info("Probing for UPnP!") intPort, extPort := 8001, 8001 nat, listener, ext, err := makeUPNPListener(intPort, extPort, logger) if err != nil { return } caps.PortMapping = true // Deferred cleanup defer func() { if err := nat.DeletePortMapping("tcp", intPort, extPort); err != nil { logger.Error(fmt.Sprintf("Port mapping delete error: %v", err)) } if err := listener.Close(); err != nil { logger.Error(fmt.Sprintf("Listener closing error: %v", err)) } }() supportsHairpin := testHairpin(listener, fmt.Sprintf("%v:%v", ext, extPort), logger) if supportsHairpin { caps.Hairpin = true } return }