package p2p import ( "fmt" "net" "strconv" "sync/atomic" . "github.com/tendermint/tendermint/binary" . "github.com/tendermint/tendermint/common" "github.com/tendermint/tendermint/p2p/upnp" ) /* Listener is part of a Server. */ type Listener interface { Connections() <-chan *Connection ExternalAddress() *NetAddress Stop() } /* DefaultListener is an implementation that works on the golang network stack. */ type DefaultListener struct { listener net.Listener extAddr *NetAddress connections chan *Connection stopped uint32 } const ( numBufferedConnections = 10 defaultExternalPort = 8770 ) func splitHostPort(addr string) (host string, port int) { host, portStr, err := net.SplitHostPort(addr) if err != nil { panic(err) } port, err = strconv.Atoi(portStr) if err != nil { panic(err) } return host, port } func NewDefaultListener(protocol string, lAddr string) Listener { // Local listen IP & port lAddrIP, lAddrPort := splitHostPort(lAddr) // Create listener listener, err := net.Listen(protocol, lAddr) if err != nil { panic(err) } // Actual listener local IP & port listenerIP, listenerPort := splitHostPort(listener.Addr().String()) log.Debug("Local listener: %v:%v", listenerIP, listenerPort) // Determine external address... var extAddr *NetAddress // 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 { panic("Could not determine external address!") } dl := &DefaultListener{ listener: listener, extAddr: extAddr, connections: make(chan *Connection, numBufferedConnections), } go dl.listenHandler() return dl } // TODO: prevent abuse, esp a bunch of connections coming from the same IP range. func (l *DefaultListener) listenHandler() { for { conn, err := l.listener.Accept() if atomic.LoadUint32(&l.stopped) == 1 { break // Go to cleanup } // listener wasn't stopped, // yet we encountered an error. if err != nil { panic(err) } c := NewConnection(conn) l.connections <- c } // 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 *Connection { return l.connections } func (l *DefaultListener) ExternalAddress() *NetAddress { return l.extAddr } func (l *DefaultListener) Stop() { if atomic.CompareAndSwapUint32(&l.stopped, 0, 1) { l.listener.Close() } } 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.Debug("Getting UPNP external address") nat, err := upnp.Discover() if err != nil { log.Debug("Could not get UPNP extrernal address: %v", err) return nil } ext, err := nat.GetExternalAddress() if err != nil { log.Debug("Could not get UPNP external address: %v", 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.Debug("Could not get UPNP external address: %v", err) return nil } log.Debug("Got UPNP external address: %v", 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 { Panicf("Unexpected error fetching 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 }