package p2p import ( "fmt" "net" "strconv" "time" . "github.com/tendermint/go-common" "github.com/tendermint/go-p2p/upnp" ) type Listener interface { Connections() <-chan net.Conn InternalAddress() *NetAddress ExternalAddress() *NetAddress String() string Stop() bool } // Implements Listener type DefaultListener struct { BaseService listener net.Listener intAddr *NetAddress extAddr *NetAddress connections chan net.Conn } const ( numBufferedConnections = 10 defaultExternalPort = 8770 tryListenSeconds = 5 ) func splitHostPort(addr string) (host string, port int) { host, portStr, err := net.SplitHostPort(addr) if err != nil { PanicSanity(err) } port, err = strconv.Atoi(portStr) if err != nil { PanicSanity(err) } return host, port } // skipUPNP: If true, does not try getUPNPExternalAddress() func NewDefaultListener(protocol string, lAddr string, skipUPNP bool) Listener { // Local listen IP & port lAddrIP, lAddrPort := splitHostPort(lAddr) // Create listener var listener net.Listener var err error for i := 0; i < tryListenSeconds; i++ { listener, err = net.Listen(protocol, lAddr) if err == nil { break } else if i < tryListenSeconds-1 { time.Sleep(time.Second * 1) } } if err != nil { PanicCrisis(err) } // Actual listener local IP & port listenerIP, listenerPort := splitHostPort(listener.Addr().String()) log.Info("Local listener", "ip", listenerIP, "port", listenerPort) // Determine internal address... var intAddr *NetAddress intAddr, err = NewNetAddressString(lAddr) if err != nil { PanicCrisis(err) } // Determine external address... var extAddr *NetAddress if !skipUPNP { // If the lAddrIP is INADDR_ANY, try UPnP if lAddrIP == "" || lAddrIP == "0.0.0.0" { extAddr = getUPNPExternalAddress(lAddrPort, listenerPort) } } // Otherwise just use the local address... if extAddr == nil { extAddr = getNaiveExternalAddress(listenerPort) } if extAddr == nil { PanicCrisis("Could not determine external address!") } dl := &DefaultListener{ listener: listener, intAddr: intAddr, extAddr: extAddr, connections: make(chan net.Conn, numBufferedConnections), } dl.BaseService = *NewBaseService(log, "DefaultListener", dl) dl.Start() // Started upon construction return dl } func (l *DefaultListener) OnStart() error { l.BaseService.OnStart() go l.listenRoutine() return nil } func (l *DefaultListener) OnStop() { l.BaseService.OnStop() l.listener.Close() } // Accept connections and pass on the channel func (l *DefaultListener) listenRoutine() { for { conn, err := l.listener.Accept() if !l.IsRunning() { break // Go to cleanup } // listener wasn't stopped, // yet we encountered an error. if err != nil { PanicCrisis(err) } l.connections <- conn } // Cleanup close(l.connections) for _ = range l.connections { // Drain } } // A channel of inbound connections. // It gets closed when the listener closes. func (l *DefaultListener) Connections() <-chan net.Conn { return l.connections } func (l *DefaultListener) InternalAddress() *NetAddress { return l.intAddr } func (l *DefaultListener) ExternalAddress() *NetAddress { return l.extAddr } // NOTE: The returned listener is already Accept()'ing. // So it's not suitable to pass into http.Serve(). func (l *DefaultListener) NetListener() net.Listener { return l.listener } func (l *DefaultListener) String() string { return fmt.Sprintf("Listener(@%v)", l.extAddr) } /* external address helpers */ // UPNP external address discovery & port mapping func getUPNPExternalAddress(externalPort, internalPort int) *NetAddress { log.Info("Getting UPNP external address") nat, err := upnp.Discover() if err != nil { log.Info("Could not perform UPNP discover", "error", err) return nil } ext, err := nat.GetExternalAddress() if err != nil { log.Info("Could not get UPNP external address", "error", err) return nil } // UPnP can't seem to get the external port, so let's just be explicit. if externalPort == 0 { externalPort = defaultExternalPort } externalPort, err = nat.AddPortMapping("tcp", externalPort, internalPort, "tendermint", 0) if err != nil { log.Info("Could not add UPNP port mapping", "error", err) return nil } log.Info("Got UPNP external address", "address", ext) return NewNetAddressIPPort(ext, uint16(externalPort)) } // TODO: use syscalls: http://pastebin.com/9exZG4rh func getNaiveExternalAddress(port int) *NetAddress { addrs, err := net.InterfaceAddrs() if err != nil { PanicCrisis(Fmt("Could not fetch interface addresses: %v", err)) } for _, a := range addrs { ipnet, ok := a.(*net.IPNet) if !ok { continue } v4 := ipnet.IP.To4() if v4 == nil || v4[0] == 127 { continue } // loopback return NewNetAddressIPPort(ipnet.IP, uint16(port)) } return nil }