Automatic 100% bootstrap using meek-signaling broker works.

Minimum viable webrtc pt now exists.
(close #1)

client/meek-webrtc.go

@@ -16,28 +16,25 @@ import (
 type MeekChannel struct {
 	// The Host header to put in the HTTP request (optional and may be
 	// different from the host name in URL).
-	Host        string
-	Method      string
-	trueURL     *url.URL
-	externalUrl string
-	transport   http.Transport // Used to make all requests.
+	Host      string
+	url       *url.URL
+	transport http.Transport // Used to make all requests.
 }
 
-// Construct a new MeekChannel, where
-// |broker| is the URL of the facilitating program which assigns proxies
-// to clients, and
-// |front| is URL of the front domain.
+// Construct a new MeekChannel, where:
+// |broker| is the full URL of the facilitating program which assigns proxies
+// to clients, and |front| is the option fronting domain.
 func NewMeekChannel(broker string, front string) *MeekChannel {
-	targetUrl, err := url.Parse(broker)
+	targetURL, err := url.Parse(broker)
 	if nil != err {
 		return nil
 	}
 	mc := new(MeekChannel)
-	mc.Host = front
-	mc.Method = "POST"
-
-	mc.trueURL = targetUrl
-	mc.externalUrl = front + "/client"
+	mc.url = targetURL
+	if "" != front { // Optional front domain.
+		mc.Host = mc.url.Host
+		mc.url.Host = front
+	}
 
 	// We make a copy of DefaultTransport because we want the default Dial
 	// and TLSHandshakeTimeout settings. But we want to disable the default
@@ -54,39 +51,24 @@ func NewMeekChannel(broker string, front string) *MeekChannel {
 func (mc *MeekChannel) Negotiate(offer *webrtc.SessionDescription) (
 	*webrtc.SessionDescription, error) {
 	data := bytes.NewReader([]byte(offer.Serialize()))
-	request, err := http.NewRequest(mc.Method, mc.externalUrl, data)
+	// Suffix with broker's client registration handler.
+	request, err := http.NewRequest("POST", mc.url.String()+"client", data)
 	if nil != err {
 		return nil, err
 	}
-	request.Host = mc.trueURL.String()
+	if "" != mc.Host { // Set true host if necessary.
+		request.Host = mc.Host
+	}
 	resp, err := mc.transport.RoundTrip(request)
 	if nil != err {
 		return nil, err
 	}
 	defer resp.Body.Close()
-	log.Println("MeekChannel Response: ", resp)
-
+	log.Printf("MeekChannel Response:\n%s\n\n", resp)
 	body, err := ioutil.ReadAll(resp.Body)
 	if nil != err {
 		return nil, err
 	}
-	log.Println("Body: ", string(body))
-	answer := webrtc.DeserializeSessionDescription(string(body))
-	return answer, nil
-}
-
-// Simple interim non-fronting HTTP POST negotiation, to be removed when more
-// general fronting is present.
-func sendOfferHTTP(url string, offer *webrtc.SessionDescription) (*webrtc.SessionDescription, error) {
-	resp, err := http.Post(url, "", bytes.NewBuffer([]byte(offer.Serialize())))
-	if err != nil {
-		return nil, err
-	}
-	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(resp.Body)
-	if err != nil {
-		return nil, err
-	}
 	answer := webrtc.DeserializeSessionDescription(string(body))
 	return answer, nil
 }

client/snowflake.go

@@ -22,18 +22,10 @@ import (
 	"git.torproject.org/pluggable-transports/goptlib.git"
 )
 
-// Hard-coded meek signalling channel for now.
-// TODO: expose as param
-const (
-	// Go fully requires the protocol to make url spec
-	FRONT_URL  = "https://www.google.com"
-	BROKER_URL = "snowflake-reg.appspot.com"
-)
-
 var ptInfo pt.ClientInfo
 var logFile *os.File
-var offerURL string
-var meekEnabled bool
+var brokerURL string
+var frontDomain string
 
 // When a connection handler starts, +1 is written to this channel; when it
 // ends, -1 is written.
@@ -180,26 +172,15 @@ func dialWebRTC(config *webrtc.Configuration, meek *MeekChannel) (
 		fmt.Fprintln(logFile, "\n"+offer.Serialize()+"\n")
 		log.Printf("----------------")
 		go func() {
-			if meekEnabled {
-				log.Println("Sending offer via meek channel...\nTarget URL: ", BROKER_URL,
-					"\nFront URL:  ", FRONT_URL)
+			if "" != brokerURL {
+				log.Println("Sending offer via meek channel...\nTarget URL: ", brokerURL,
+					"\nFront URL:  ", frontDomain)
 				answer, err := meek.Negotiate(pc.LocalDescription())
 				if nil != err {
 					log.Printf("MeekChannel signaling error: %s", err)
 				}
 				if nil == answer {
 					log.Printf("MeekChannel: No answer received.")
-				} else {
-					log.Println("Recieved answer from Meek channel: \n\n",
-						answer.Serialize(), "\n")
-					// TODO: Once this is correct, uncomment and remove copy-paste stuff.
-					// signalChan <- answer
-				}
-			}
-			if offerURL != "" {
-				answer, err := sendOfferHTTP(offerURL, offer)
-				if err != nil {
-					log.Println(err)
 				} else {
 					signalChan <- answer
 				}
@@ -214,7 +195,7 @@ func dialWebRTC(config *webrtc.Configuration, meek *MeekChannel) (
 		pc.Close()
 		return nil, fmt.Errorf("no answer received")
 	}
-	log.Printf("Received Answer: %s", answer.Serialize())
+	log.Printf("Received Answer:\n\n%s\n", answer.Sdp)
 	err = pc.SetRemoteDescription(answer)
 	if err != nil {
 		pc.Close()
@@ -257,7 +238,7 @@ func handler(conn *pt.SocksConn) error {
 
 	config := webrtc.NewConfiguration(
 		webrtc.OptionIceServer("stun:stun.l.google.com:19302"))
-	meek := NewMeekChannel(BROKER_URL, FRONT_URL)
+	meek := NewMeekChannel(brokerURL, frontDomain)
 	remote, err := dialWebRTC(config, meek)
 	if err != nil {
 		conn.Reject()
@@ -318,8 +299,8 @@ func readSignalingMessages(f *os.File) {
 func main() {
 	var err error
 
-	flag.StringVar(&offerURL, "url", "", "do signalling through URL")
-	flag.BoolVar(&meekEnabled, "meek", false, "use domain fronted signaling")
+	flag.StringVar(&brokerURL, "url", "", "URL of signaling broker")
+	flag.StringVar(&frontDomain, "front", "", "front domain")
 	flag.Parse()
 
 	logFile, err = os.OpenFile("snowflake.log", os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
@@ -328,10 +309,9 @@ func main() {
 	}
 	defer logFile.Close()
 	log.SetOutput(logFile)
-
 	log.Println("starting")
 
-	if offerURL == "" && !meekEnabled {
+	if "" == brokerURL {
 		log.Println("No HTTP signaling detected. Waiting for a \"signal\" pipe...")
 		// This FIFO receives signaling messages.
 		err = syscall.Mkfifo("signal", 0600)

client/torrc

@@ -1,5 +1,8 @@
 UseBridges 1
 DataDirectory datadir
 
-ClientTransportPlugin snowflake exec ./client
+ClientTransportPlugin snowflake exec ./client \
+-url https://snowflake-reg.appspot.com/ \
+-front www.google.com
+
 Bridge snowflake 0.0.3.0:1

client/torrc-manual

@@ -0,0 +1,6 @@
+UseBridges 1
+DataDirectory datadir
+
+ClientTransportPlugin snowflake exec ./client
+
+Bridge snowflake 0.0.3.0:1