package nat import ( "errors" "fmt" "net" "strings" "time" "github.com/fjl/goupnp" "github.com/fjl/goupnp/dcps/internetgateway1" "github.com/fjl/goupnp/dcps/internetgateway2" ) type upnp struct { dev *goupnp.RootDevice service string client upnpClient } type upnpClient interface { GetExternalIPAddress() (string, error) AddPortMapping(string, uint16, string, uint16, string, bool, string, uint32) error DeletePortMapping(string, uint16, string) error GetNATRSIPStatus() (sip bool, nat bool, err error) } func (n *upnp) ExternalIP() (addr net.IP, err error) { ipString, err := n.client.GetExternalIPAddress() if err != nil { return nil, err } ip := net.ParseIP(ipString) if ip == nil { return nil, errors.New("bad IP in response") } return ip, nil } func (n *upnp) AddMapping(protocol string, extport, intport int, desc string, lifetime time.Duration) error { ip, err := n.internalAddress() if err != nil { return nil } protocol = strings.ToUpper(protocol) lifetimeS := uint32(lifetime / time.Second) return n.client.AddPortMapping("", uint16(extport), protocol, uint16(intport), ip.String(), true, desc, lifetimeS) } func (n *upnp) internalAddress() (net.IP, error) { devaddr, err := net.ResolveUDPAddr("udp4", n.dev.URLBase.Host) if err != nil { return nil, err } ifaces, err := net.Interfaces() if err != nil { return nil, err } for _, iface := range ifaces { addrs, err := iface.Addrs() if err != nil { return nil, err } for _, addr := range addrs { switch x := addr.(type) { case *net.IPNet: if x.Contains(devaddr.IP) { return x.IP, nil } } } } return nil, fmt.Errorf("could not find local address in same net as %v", devaddr) } func (n *upnp) DeleteMapping(protocol string, extport, intport int) error { return n.client.DeletePortMapping("", uint16(extport), strings.ToUpper(protocol)) } func (n *upnp) String() string { return "UPNP " + n.service } // discoverUPnP searches for Internet Gateway Devices // and returns the first one it can find on the local network. func discoverUPnP() Interface { found := make(chan *upnp, 2) // IGDv1 go discover(found, internetgateway1.URN_WANConnectionDevice_1, func(dev *goupnp.RootDevice, sc goupnp.ServiceClient) *upnp { switch sc.Service.ServiceType { case internetgateway1.URN_WANIPConnection_1: return &upnp{dev, "IGDv1-IP1", &internetgateway1.WANIPConnection1{sc}} case internetgateway1.URN_WANPPPConnection_1: return &upnp{dev, "IGDv1-PPP1", &internetgateway1.WANPPPConnection1{sc}} } return nil }) // IGDv2 go discover(found, internetgateway2.URN_WANConnectionDevice_2, func(dev *goupnp.RootDevice, sc goupnp.ServiceClient) *upnp { switch sc.Service.ServiceType { case internetgateway2.URN_WANIPConnection_1: return &upnp{dev, "IGDv2-IP1", &internetgateway2.WANIPConnection1{sc}} case internetgateway2.URN_WANIPConnection_2: return &upnp{dev, "IGDv2-IP2", &internetgateway2.WANIPConnection2{sc}} case internetgateway2.URN_WANPPPConnection_1: return &upnp{dev, "IGDv2-PPP1", &internetgateway2.WANPPPConnection1{sc}} } return nil }) for i := 0; i < cap(found); i++ { if c := <-found; c != nil { return c } } return nil } func discover(out chan<- *upnp, target string, matcher func(*goupnp.RootDevice, goupnp.ServiceClient) *upnp) { devs, err := goupnp.DiscoverDevices(target) if err != nil { return } found := false for i := 0; i < len(devs) && !found; i++ { if devs[i].Root == nil { continue } devs[i].Root.Device.VisitServices(func(service *goupnp.Service) { if found { return } // check for a matching IGD service sc := goupnp.ServiceClient{service.NewSOAPClient(), devs[i].Root, service} upnp := matcher(devs[i].Root, sc) if upnp == nil { return } // check whether port mapping is enabled if _, nat, err := upnp.client.GetNATRSIPStatus(); err != nil || !nat { return } out <- upnp found = true }) } if !found { out <- nil } }