1 files changed, 334 insertions, 0 deletions
diff --git a/natupnp.go b/natupnp.go
new file mode 100644
index 000000000..e4072d0dd
--- /dev/null
+++ b/natupnp.go
@@ -0,0 +1,334 @@
+package eth
+
+// 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 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()
+
+	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 < 3; 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 := "<?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: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")
+
+	// log.Stderr("soapRequest ", req)
+	//fmt.Println(fullMessage)
+
+	r, err = http.DefaultClient.Do(req)
+	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 := "<u:GetStatusInfo xmlns:u=\"urn:schemas-upnp-org:service:WANIPConnection:1\">\r\n" +
+		"</u:GetStatusInfo>"
+
+	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 := "<u:AddPortMapping xmlns:u=\"urn:schemas-upnp-org: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)
+	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 := "<u:DeletePortMapping xmlns:u=\"urn:schemas-upnp-org: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)
+	if err != nil {
+		return
+	}
+
+	// TODO: check response to see if the port was deleted
+	// log.Println(message, response)
+	_ = response
+	return
+}