package eth import ( //natpmp "code.google.com/p/go-nat-pmp" "fmt" "net" natpmp "github.com/jackpal/go-nat-pmp" ) // Adapt the NAT-PMP protocol to the NAT interface // TODO: // + Register for changes to the external address. // + Re-register port mapping when router reboots. // + A mechanism for keeping a port mapping registered. type natPMPClient struct { client *natpmp.Client } func NewNatPMP(gateway net.IP) (nat NAT) { return &natPMPClient{natpmp.NewClient(gateway)} } func (n *natPMPClient) GetExternalAddress() (addr net.IP, err error) { response, err := n.client.GetExternalAddress() if err != nil { return } ip := response.ExternalIPAddress addr = net.IPv4(ip[0], ip[1], ip[2], ip[3]) return } func (n *natPMPClient) AddPortMapping(protocol string, externalPort, internalPort int, description string, timeout int) (mappedExternalPort int, err error) { if timeout <= 0 { err = fmt.Errorf("timeout must not be <= 0") return } // Note order of port arguments is switched between our AddPortMapping and the client's AddPortMapping. response, err := n.client.AddPortMapping(protocol, internalPort, externalPort, timeout) if err != nil { return } mappedExternalPort = int(response.MappedExternalPort) return } func (n *natPMPClient) DeletePortMapping(protocol string, externalPort, internalPort int) (err error) { // To destroy a mapping, send an add-port with // an internalPort of the internal port to destroy, an external port of zero and a time of zero. _, err = n.client.AddPortMapping(protocol, internalPort, 0, 0) return }