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