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