Automatic 100% bootstrap using meek-signaling broker works.

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

README.md

@@ -4,25 +4,78 @@ A Pluggable Transport using WebRTC
 
 ### Status
 
-- Successfully bootstraps over WebRTC, both directly to a server plugin,
+- Successful automatic bootstraps with a WebRTC transport,
-  as well as through the browser which proxies WebRTC to websocket.
+  using HTTP signaling (with optional domain fronting) speaking to
-- Needs work on signaling with the broker.
+  a multitude of volunteer "snowflakes".
+- Needs a lot more work though.
 
 ### Usage
 
-There are currently two ways to try this:
+
-- Directly to the go-webrtc server plugin.
+
-- Through a browser snowflake proxy.
+```
+cd client/
+go build
+tor -f torrc
+```
+
+And it will start the client plugin with the following `torrc`
+options:
+```
+ClientTransportPlugin snowflake exec ./client \
+--url https://snowflake-reg.appspot.com/ \
+--front www.google.com
+```
+
+It will speak to the Broker, get matched with a "snowflake" browser proxy,
+and negotiate a WebRTC PeerConnection.
+After that, it should bootstrap to 100%.
+
+To see logs, do `tail -F snowflake.log` in a second terminal.
+
+You can modify the `torrc` to use your own broker,
+or remove the options entirely which will default to the old copy paste
+method (see `torrc-manual`):
+
+```
+ClientTransportPlugin snowflake exec ./client --meek
+```
+
+Also, it is possible to connect directly to the go-webrtc server plugin
+(skipping all the browser snowflake / broker stuff - see appendix)
+
+### Building a Snowflake Proxy
+
+This will only work if there are any browser snowflakes running at all.
+To run your own, first make sure coffeescript is installed.
+Then, build with:
+
+```
+cd proxy/
+cake build
+```
+(Type `cake` by itself to see possible commands)
+
+Then, start a local http server in the `proxy/build/` in any way you like.
+For instance:
+
+```
+cd build/
+python -m http.server
+```
+
+Open a browser tab to `0.0.0.0:8000/snowflake.html`.
+
+TODO: Turn the snowflake proxy into a more deployable badge.
+
+### Appendix
+
+##### -- Testing directly via WebRTC Server --
 
 Using the server plugin uses an HTTP server that simulates the interaction
 that a client would have with a broker.
 Using the browser proxy (which will soon be the only way) requires copy and
 pasting between 3 terminals and a browser tab.
-Once a signaling broker is implemented
-([issue #1](https://github.com/keroserene/snowflake/issues/1))
-this will become much simpler to use.
-
-##### -- Via WebRTC Server --
 
 Edit server/torrc and add "-http 127.0.0.1:8080" to the end of the
 ServerTransportPlugin line:
@@ -42,14 +95,6 @@ ClientTransportPlugin line:
 ClientTransportPlugin snowflake exec ./client -url http://127.0.0.1:8080/
 ```
 
-```
-cd client/
-go build
-tor -f torrc
-```
-
-At this point the tor client should bootstrap to 100%.
-
 ##### -- Via Browser Proxy --
 
 Open up three terminals for the **client:**
@@ -60,39 +105,11 @@ B: `cat > signal`
 
 C: `tail -F snowflake.log`
 
-
+Then, in the browser proxy:
-To connect through the WebRTC browser proxy, first make sure
-coffeescript is installed. Then, build with:
-```
-cd proxy/
-cake build
-```
-
-Then start a local http server in the `proxy/build/` in any way you like.
-For instance:
-
-```
-cd build/
-python -m http.server
-```
-
-Open a browser tab to `0.0.0.0:8000/snowflake.html`.
-Input your desired relay address, or nothing/gibberish, which will cause
-snowflake to just use a default relay.
 
 - Look for the offer in terminal C; copy and paste it into the browser.
 - Copy and paste the answer generated in the browser back to terminal B.
 - Once WebRTC successfully connects, the browser terminal should turn green.
   Shortly after, the tor client should bootstrap to 100%.
 
-
-### More
-
-To try using the Meek signaling channel (which will soon be fully ready),
-add the `--meek` flag like so:
-
-```
-ClientTransportPlugin snowflake exec ./client --meek
-```
-
 More documentation on the way.

client/meek-webrtc.go

@@ -17,27 +17,24 @@ 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
+	url       *url.URL
-	trueURL     *url.URL
-	externalUrl string
 	transport http.Transport // Used to make all requests.
 }
 
-// Construct a new MeekChannel, where
+// Construct a new MeekChannel, where:
-// |broker| is the URL of the facilitating program which assigns proxies
+// |broker| is the full URL of the facilitating program which assigns proxies
-// to clients, and
+// to clients, and |front| is the option fronting domain.
-// |front| is URL of the front 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.url = targetURL
-	mc.Method = "POST"
+	if "" != front { // Optional front domain.
-
+		mc.Host = mc.url.Host
-	mc.trueURL = targetUrl
+		mc.url.Host = front
-	mc.externalUrl = front + "/client"
+	}
 
 	// 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 brokerURL string
-var meekEnabled bool
+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 {
+			if "" != brokerURL {
-				log.Println("Sending offer via meek channel...\nTarget URL: ", BROKER_URL,
+				log.Println("Sending offer via meek channel...\nTarget URL: ", brokerURL,
-					"\nFront URL:  ", FRONT_URL)
+					"\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.StringVar(&brokerURL, "url", "", "URL of signaling broker")
-	flag.BoolVar(&meekEnabled, "meek", false, "use domain fronted signaling")
+	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