package p2p
// Just enough UPnP to be able to forward ports
//
import (
"bytes"
"encoding/xml"
"errors"
"net"
"net/http"
"os"
"strconv"
"strings"
"time"
)
type upnpNAT struct {
serviceURL string
ourIP string
}
func upnpDiscover(attempts int) (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()
err = socket.SetDeadline(time.Now().Add(10 * time.Second))
if err != nil {
return
}
st := "ST: urn:schemas-upnp-org:device:InternetGatewayDevice:1\r\n"
buf := bytes.NewBufferString(
"M-SEARCH * HTTP/1.1\r\n" +
"HOST: 239.255.255.250:1900\r\n" +
st +
"MAN: \"ssdp:discover\"\r\n" +
"MX: 2\r\n\r\n")
message := buf.Bytes()
answerBytes := make([]byte, 1024)
for i := 0; i < attempts; i++ {
_, err = socket.WriteToUDP(message, ssdp)
if err != nil {
return
}
var n int
n, _, err = socket.ReadFromUDP(answerBytes)
if err != nil {
continue
// socket.Close()
// return
}
answer := string(answerBytes[0:n])
if strings.Index(answer, "\r\n"+st) < 0 {
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 := loc[0:endIndex]
var serviceURL string
serviceURL, err = getServiceURL(locURL)
if err != nil {
return
}
var ourIP string
ourIP, err = getOurIP()
if err != nil {
return
}
nat = &upnpNAT{serviceURL: serviceURL, ourIP: ourIP}
return
}
err = errors.New("UPnP port discovery failed.")
return
}
// service represents the Service type in an UPnP xml description.
// Only the parts we care about are present and thus the xml may have more
// fields than present in the structure.
type service struct {
ServiceType string `xml:"serviceType"`
ControlURL string `xml:"controlURL"`
}
// deviceList represents the deviceList type in an UPnP xml description.
// Only the parts we care about are present and thus the xml may have more
// fields than present in the structure.
type deviceList struct {
XMLName xml.Name `xml:"deviceList"`
Device []device `xml:"device"`
}
// serviceList represents the serviceList type in an UPnP xml description.
// Only the parts we care about are present and thus the xml may have more
// fields than present in the structure.
type serviceList struct {
XMLName xml.Name `xml:"serviceList"`
Service []service `xml:"service"`
}
// device represents the device type in an UPnP xml description.
// Only the parts we care about are present and thus the xml may have more
// fields than present in the structure.
type device struct {
XMLName xml.Name `xml:"device"`
DeviceType string `xml:"deviceType"`
DeviceList deviceList `xml:"deviceList"`
ServiceList serviceList `xml:"serviceList"`
}
// specVersion represents the specVersion in a UPnP xml description.
// Only the parts we care about are present and thus the xml may have more
// fields than present in the structure.
type specVersion struct {
XMLName xml.Name `xml:"specVersion"`
Major int `xml:"major"`
Minor int `xml:"minor"`
}
// root represents the Root document for a UPnP xml description.
// Only the parts we care about are present and thus the xml may have more
// fields than present in the structure.
type root struct {
XMLName xml.Name `xml:"root"`
SpecVersion specVersion
Device device
}
func getChildDevice(d *device, deviceType string) *device {
dl := d.DeviceList.Device
for i := 0; i < len(dl); i++ {
if dl[i].DeviceType == deviceType {
return &dl[i]
}
}
return nil
}
func getChildService(d *device, serviceType string) *service {
sl := d.ServiceList.Service
for i := 0; i < len(sl); i++ {
if sl[i].ServiceType == serviceType {
return &sl[i]
}
}
return nil
}
func getOurIP() (ip string, err error) {
hostname, err := os.Hostname()
if err != nil {
return
}
p, err := net.LookupIP(hostname)
if err != nil && len(p) > 0 {
return
}
return p[0].String(), nil
}
func getServiceURL(rootURL string) (url 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 a.DeviceType != "urn:schemas-upnp-org:device:InternetGatewayDevice:1" {
err = errors.New("No InternetGatewayDevice")
return
}
b := getChildDevice(a, "urn:schemas-upnp-org:device:WANDevice:1")
if b == nil {
err = errors.New("No WANDevice")
return
}
c := getChildDevice(b, "urn:schemas-upnp-org:device:WANConnectionDevice:1")
if c == nil {
err = errors.New("No WANConnectionDevice")
return
}
d := getChildService(c, "urn:schemas-upnp-org:service:WANIPConnection:1")
if d == nil {
err = errors.New("No WANIPConnection")
return
}
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 string) (r *http.Response, err error) {
fullMessage := "" +
"\r\n" +
"" + message + ""
req, err := http.NewRequest("POST", url, strings.NewReader(fullMessage))
if err != nil {
return
}
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:schemas-upnp-org:service:WANIPConnection:1#"+function+"\"")
req.Header.Set("Connection", "Close")
req.Header.Set("Cache-Control", "no-cache")
req.Header.Set("Pragma", "no-cache")
r, err = http.DefaultClient.Do(req)
if err != nil {
return
}
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) getStatusInfo() (info statusInfo, err error) {
message := "\r\n" +
""
var response *http.Response
response, err = soapRequest(n.serviceURL, "GetStatusInfo", message)
if err != nil {
return
}
// TODO: Write a soap reply parser. It has to eat the Body and envelope tags...
response.Body.Close()
return
}
func (n *upnpNAT) GetExternalAddress() (addr net.IP, err error) {
info, err := n.getStatusInfo()
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 := "\r\n" +
"" + strconv.Itoa(externalPort)
message += "" + protocol + ""
message += "" + strconv.Itoa(internalPort) + "" +
"" + n.ourIP + "" +
"1"
message += description +
"" + strconv.Itoa(timeout) +
""
var response *http.Response
response, err = soapRequest(n.serviceURL, "AddPortMapping", message)
if err != nil {
return
}
// TODO: check response to see if the port was forwarded
// log.Println(message, response)
mappedExternalPort = externalPort
_ = response
return
}
func (n *upnpNAT) DeletePortMapping(protocol string, externalPort, internalPort int) (err error) {
message := "\r\n" +
"" + strconv.Itoa(externalPort) +
"" + protocol + "" +
""
var response *http.Response
response, err = soapRequest(n.serviceURL, "DeletePortMapping", message)
if err != nil {
return
}
// TODO: check response to see if the port was deleted
// log.Println(message, response)
_ = response
return
}