// Taken from taipei-torrent.
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// Just enough UPnP to be able to forward ports
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// For more information, see: http://www.upnp-hacks.org/upnp.html
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package upnp
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// TODO: use syscalls to get actual ourIP, see issue #712
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import (
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"bytes"
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"encoding/xml"
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"errors"
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"io/ioutil"
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"net"
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"net/http"
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"strconv"
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"strings"
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"time"
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)
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type upnpNAT struct {
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serviceURL string
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ourIP string
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urnDomain string
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}
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// protocol is either "udp" or "tcp"
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type NAT interface {
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GetExternalAddress() (addr net.IP, err error)
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AddPortMapping(protocol string, externalPort, internalPort int, description string, timeout int) (mappedExternalPort int, err error)
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DeletePortMapping(protocol string, externalPort, internalPort int) (err error)
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}
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func Discover() (nat NAT, err error) {
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ssdp, err := net.ResolveUDPAddr("udp4", "239.255.255.250:1900")
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if err != nil {
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return
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}
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conn, err := net.ListenPacket("udp4", ":0")
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if err != nil {
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return
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}
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socket := conn.(*net.UDPConn)
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defer socket.Close()
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if err := socket.SetDeadline(time.Now().Add(3 * time.Second)); err != nil {
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return nil, err
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}
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st := "InternetGatewayDevice:1"
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buf := bytes.NewBufferString(
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"M-SEARCH * HTTP/1.1\r\n" +
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"HOST: 239.255.255.250:1900\r\n" +
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"ST: ssdp:all\r\n" +
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"MAN: \"ssdp:discover\"\r\n" +
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"MX: 2\r\n\r\n")
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message := buf.Bytes()
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answerBytes := make([]byte, 1024)
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for i := 0; i < 3; i++ {
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_, err = socket.WriteToUDP(message, ssdp)
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if err != nil {
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return
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}
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var n int
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_, _, err = socket.ReadFromUDP(answerBytes)
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for {
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n, _, err = socket.ReadFromUDP(answerBytes)
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if err != nil {
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break
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}
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answer := string(answerBytes[0:n])
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if !strings.Contains(answer, st) {
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continue
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}
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// HTTP header field names are case-insensitive.
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// http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
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locString := "\r\nlocation:"
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answer = strings.ToLower(answer)
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locIndex := strings.Index(answer, locString)
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if locIndex < 0 {
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continue
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}
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loc := answer[locIndex+len(locString):]
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endIndex := strings.Index(loc, "\r\n")
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if endIndex < 0 {
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continue
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}
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locURL := strings.TrimSpace(loc[0:endIndex])
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var serviceURL, urnDomain string
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serviceURL, urnDomain, err = getServiceURL(locURL)
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if err != nil {
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return
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}
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var ourIP net.IP
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ourIP, err = localIPv4()
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if err != nil {
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return
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}
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nat = &upnpNAT{serviceURL: serviceURL, ourIP: ourIP.String(), urnDomain: urnDomain}
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return
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}
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}
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err = errors.New("UPnP port discovery failed.")
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return
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}
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type Envelope struct {
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XMLName xml.Name `xml:"http://schemas.xmlsoap.org/soap/envelope/ Envelope"`
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Soap *SoapBody
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}
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type SoapBody struct {
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XMLName xml.Name `xml:"http://schemas.xmlsoap.org/soap/envelope/ Body"`
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ExternalIP *ExternalIPAddressResponse
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}
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type ExternalIPAddressResponse struct {
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XMLName xml.Name `xml:"GetExternalIPAddressResponse"`
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IPAddress string `xml:"NewExternalIPAddress"`
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}
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type ExternalIPAddress struct {
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XMLName xml.Name `xml:"NewExternalIPAddress"`
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IP string
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}
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type UPNPService struct {
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ServiceType string `xml:"serviceType"`
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ControlURL string `xml:"controlURL"`
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}
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type DeviceList struct {
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Device []Device `xml:"device"`
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}
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type ServiceList struct {
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Service []UPNPService `xml:"service"`
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}
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type Device struct {
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XMLName xml.Name `xml:"device"`
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DeviceType string `xml:"deviceType"`
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DeviceList DeviceList `xml:"deviceList"`
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ServiceList ServiceList `xml:"serviceList"`
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}
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type Root struct {
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Device Device
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}
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func getChildDevice(d *Device, deviceType string) *Device {
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dl := d.DeviceList.Device
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for i := 0; i < len(dl); i++ {
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if strings.Contains(dl[i].DeviceType, deviceType) {
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return &dl[i]
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}
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}
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return nil
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}
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func getChildService(d *Device, serviceType string) *UPNPService {
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sl := d.ServiceList.Service
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for i := 0; i < len(sl); i++ {
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if strings.Contains(sl[i].ServiceType, serviceType) {
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return &sl[i]
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}
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}
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return nil
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}
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func localIPv4() (net.IP, error) {
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tt, err := net.Interfaces()
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if err != nil {
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return nil, err
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}
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for _, t := range tt {
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aa, err := t.Addrs()
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if err != nil {
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return nil, err
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}
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for _, a := range aa {
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ipnet, ok := a.(*net.IPNet)
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if !ok {
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continue
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}
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v4 := ipnet.IP.To4()
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if v4 == nil || v4[0] == 127 { // loopback address
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continue
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}
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return v4, nil
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}
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}
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return nil, errors.New("cannot find local IP address")
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}
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func getServiceURL(rootURL string) (url, urnDomain string, err error) {
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r, err := http.Get(rootURL)
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if err != nil {
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return
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}
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defer r.Body.Close()
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if r.StatusCode >= 400 {
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err = errors.New(string(r.StatusCode))
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return
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}
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var root Root
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err = xml.NewDecoder(r.Body).Decode(&root)
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if err != nil {
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return
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}
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a := &root.Device
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if !strings.Contains(a.DeviceType, "InternetGatewayDevice:1") {
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err = errors.New("No InternetGatewayDevice")
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return
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}
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b := getChildDevice(a, "WANDevice:1")
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if b == nil {
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err = errors.New("No WANDevice")
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return
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}
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c := getChildDevice(b, "WANConnectionDevice:1")
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if c == nil {
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err = errors.New("No WANConnectionDevice")
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return
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}
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d := getChildService(c, "WANIPConnection:1")
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if d == nil {
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// Some routers don't follow the UPnP spec, and put WanIPConnection under WanDevice,
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// instead of under WanConnectionDevice
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d = getChildService(b, "WANIPConnection:1")
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if d == nil {
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err = errors.New("No WANIPConnection")
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return
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}
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}
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// Extract the domain name, which isn't always 'schemas-upnp-org'
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urnDomain = strings.Split(d.ServiceType, ":")[1]
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url = combineURL(rootURL, d.ControlURL)
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return
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}
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func combineURL(rootURL, subURL string) string {
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protocolEnd := "://"
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protoEndIndex := strings.Index(rootURL, protocolEnd)
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a := rootURL[protoEndIndex+len(protocolEnd):]
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rootIndex := strings.Index(a, "/")
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return rootURL[0:protoEndIndex+len(protocolEnd)+rootIndex] + subURL
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}
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func soapRequest(url, function, message, domain string) (r *http.Response, err error) {
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fullMessage := "<?xml version=\"1.0\" ?>" +
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"<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\" s:encodingStyle=\"http://schemas.xmlsoap.org/soap/encoding/\">\r\n" +
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"<s:Body>" + message + "</s:Body></s:Envelope>"
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req, err := http.NewRequest("POST", url, strings.NewReader(fullMessage))
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if err != nil {
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return nil, err
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}
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req.Header.Set("Content-Type", "text/xml ; charset=\"utf-8\"")
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req.Header.Set("User-Agent", "Darwin/10.0.0, UPnP/1.0, MiniUPnPc/1.3")
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//req.Header.Set("Transfer-Encoding", "chunked")
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req.Header.Set("SOAPAction", "\"urn:"+domain+":service:WANIPConnection:1#"+function+"\"")
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req.Header.Set("Connection", "Close")
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req.Header.Set("Cache-Control", "no-cache")
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req.Header.Set("Pragma", "no-cache")
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// log.Stderr("soapRequest ", req)
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r, err = http.DefaultClient.Do(req)
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if err != nil {
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return nil, err
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}
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/*if r.Body != nil {
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defer r.Body.Close()
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}*/
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if r.StatusCode >= 400 {
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// log.Stderr(function, r.StatusCode)
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err = errors.New("Error " + strconv.Itoa(r.StatusCode) + " for " + function)
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r = nil
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return
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}
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return
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}
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type statusInfo struct {
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externalIpAddress string
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}
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func (n *upnpNAT) getExternalIPAddress() (info statusInfo, err error) {
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message := "<u:GetExternalIPAddress xmlns:u=\"urn:" + n.urnDomain + ":service:WANIPConnection:1\">\r\n" +
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"</u:GetExternalIPAddress>"
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var response *http.Response
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response, err = soapRequest(n.serviceURL, "GetExternalIPAddress", message, n.urnDomain)
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if response != nil {
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defer response.Body.Close()
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}
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if err != nil {
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return
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}
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var envelope Envelope
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data, err := ioutil.ReadAll(response.Body)
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if err != nil {
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return
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}
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reader := bytes.NewReader(data)
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err = xml.NewDecoder(reader).Decode(&envelope)
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if err != nil {
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return
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}
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info = statusInfo{envelope.Soap.ExternalIP.IPAddress}
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if err != nil {
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return
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}
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return
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}
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func (n *upnpNAT) GetExternalAddress() (addr net.IP, err error) {
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info, err := n.getExternalIPAddress()
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if err != nil {
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return
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}
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addr = net.ParseIP(info.externalIpAddress)
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return
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}
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func (n *upnpNAT) AddPortMapping(protocol string, externalPort, internalPort int, description string, timeout int) (mappedExternalPort int, err error) {
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// A single concatenation would break ARM compilation.
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message := "<u:AddPortMapping xmlns:u=\"urn:" + n.urnDomain + ":service:WANIPConnection:1\">\r\n" +
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"<NewRemoteHost></NewRemoteHost><NewExternalPort>" + strconv.Itoa(externalPort)
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message += "</NewExternalPort><NewProtocol>" + protocol + "</NewProtocol>"
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message += "<NewInternalPort>" + strconv.Itoa(internalPort) + "</NewInternalPort>" +
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"<NewInternalClient>" + n.ourIP + "</NewInternalClient>" +
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"<NewEnabled>1</NewEnabled><NewPortMappingDescription>"
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message += description +
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"</NewPortMappingDescription><NewLeaseDuration>" + strconv.Itoa(timeout) +
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"</NewLeaseDuration></u:AddPortMapping>"
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var response *http.Response
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response, err = soapRequest(n.serviceURL, "AddPortMapping", message, n.urnDomain)
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if response != nil {
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defer response.Body.Close()
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}
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if err != nil {
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return
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}
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// TODO: check response to see if the port was forwarded
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// log.Println(message, response)
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// JAE:
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// body, err := ioutil.ReadAll(response.Body)
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// fmt.Println(string(body), err)
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mappedExternalPort = externalPort
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_ = response
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return
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}
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func (n *upnpNAT) DeletePortMapping(protocol string, externalPort, internalPort int) (err error) {
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message := "<u:DeletePortMapping xmlns:u=\"urn:" + n.urnDomain + ":service:WANIPConnection:1\">\r\n" +
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"<NewRemoteHost></NewRemoteHost><NewExternalPort>" + strconv.Itoa(externalPort) +
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"</NewExternalPort><NewProtocol>" + protocol + "</NewProtocol>" +
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"</u:DeletePortMapping>"
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var response *http.Response
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response, err = soapRequest(n.serviceURL, "DeletePortMapping", message, n.urnDomain)
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if response != nil {
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defer response.Body.Close()
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}
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if err != nil {
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return
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}
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// TODO: check response to see if the port was deleted
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// log.Println(message, response)
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_ = response
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return
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}
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