begin appengine rendezvous component - domain fronting works,

although it just reflects the offer.
next step is to retrieve browser proxy answer (#1)

client/meek-webrtc.go

@@ -5,6 +5,7 @@ package main
 import (
 	"bytes"
 	"io/ioutil"
+	"log"
 	"net/http"
 	"net/url"
 
@@ -31,8 +32,9 @@ func NewRequestInfo(meekUrl string, front string) *RequestInfo {
 		return nil
 	}
 	info.URL = requestUrl
-	info.Host = info.URL.Host
-	info.URL.Host = front
+	info.Host = front
+	// info.URL.Host = front
+	// info.Host = info.URL.Host
 	return info
 }
 
@@ -57,13 +59,13 @@ func NewMeekChannel(info *RequestInfo) *MeekChannel {
 
 // Do an HTTP roundtrip using the payload data in buf.
 func (m *MeekChannel) roundTripHTTP(buf []byte) (*http.Response, error) {
-	req, err := http.NewRequest("POST", m.info.URL.String(), bytes.NewReader(buf))
+	// Compose an innocent looking request.
+	req, err := http.NewRequest("POST", m.info.Host+"/reg/123", bytes.NewReader(buf))
 	if nil != err {
 		return nil, err
 	}
-	if "" != m.info.Host {
-		req.Host = m.info.Host
-	}
+	// Set actually desired target host.
+	req.Host = m.info.URL.String()
 	// req.Header.Set("X-Session-Id", m.info.SessionID)
 	return m.transport.RoundTrip(req)
 }
@@ -78,7 +80,12 @@ func (m *MeekChannel) Negotiate(offer *webrtc.SessionDescription) (
 		return nil, err
 	}
 	defer resp.Body.Close()
+	log.Println("MeekChannel Response: ", resp)
 	body, err := ioutil.ReadAll(resp.Body)
+	if nil != err {
+		return nil, err
+	}
+	log.Println("MeekChannel Body: ", string(body))
 	answer := webrtc.DeserializeSessionDescription(string(body))
 	return answer, nil
 }

client/snowflake.go

@@ -25,8 +25,9 @@ import (
 // Hard-coded meek signalling channel for now.
 // TODO: expose as param
 const (
-	MEEK_URL     = "not implemented yet"
-	FRONT_DOMAIN = "www.google.com"
+	MEEK_URL     = "snowflake-reg.appspot.com"
+	FRONT_DOMAIN = "https://www.google.com"
+	// FRONT_DOMAIN = "https://www.google.com"
 )
 
 var ptInfo pt.ClientInfo
@@ -187,7 +188,11 @@ func dialWebRTC(config *webrtc.Configuration, meek *MeekChannel) (
 			// if nil == answer {
 			// 	log.Printf("No answer received from meek channel.")
 			// } else {
-			// 	signalChan <- answer
+			// 	// TODO: Once this is correct, uncomment and remove copy-paste
+			// 	// signalling.
+			// 	log.Println("Recieved answer from Meek channel: \n",
+			// 		answer.Serialize())
+			// 	// signalChan <- answer
 			// }
 			if offerURL != "" {
 				answer, err := sendOfferHTTP(offerURL, offer)
@@ -207,7 +212,7 @@ func dialWebRTC(config *webrtc.Configuration, meek *MeekChannel) (
 		pc.Close()
 		return nil, fmt.Errorf("no answer received")
 	}
-	log.Printf("got answer %s", answer.Serialize())
+	log.Printf("Received Answer: %s", answer.Serialize())
 	err = pc.SetRemoteDescription(answer)
 	if err != nil {
 		pc.Close()

rendezvous/app.yaml

@@ -0,0 +1,10 @@
+# override this with appcfg.py -A $YOUR_APP_ID
+application: snowflake-reg
+version: 1
+runtime: go
+api_version: go1
+
+handlers:
+- url: /.*
+  script: _go_app
+  secure: always

rendezvous/config.go

@@ -0,0 +1,16 @@
+/*
+This is the server-side code that runs on Google App Engine for the
+"appspot" registration method.
+
+See doc/appspot-howto.txt for more details about setting up an
+application, and advice on running one.
+
+To upload a new version:
+$ torify ~/go_appengine/appcfg.py --no_cookies -A $YOUR_APP_ID update .
+*/
+package snowflake_reg
+
+// host:port/basepath of the facilitator you want to register with
+// for example, fp-facilitator.org or example.com:12345/facilitator
+// https:// and /reg/ will be prepended and appended respectively.
+const SNOWFLAKE_FACILITATOR = ""

rendezvous/snowflake-reg.go

@@ -0,0 +1,65 @@
+package snowflake_reg
+
+import (
+	// "io"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"path"
+
+	// "appengine"
+	// "appengine/urlfetch"
+)
+
+// This is an intermediate step - a basic hardcoded appengine rendezvous
+// to a single browser snowflake.
+
+var snowflakeProxy = ""
+
+func robotsTxtHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.Write([]byte("User-agent: *\nDisallow:\n"))
+}
+
+func ipHandler(w http.ResponseWriter, r *http.Request) {
+	remoteAddr := r.RemoteAddr
+	if net.ParseIP(remoteAddr).To4() == nil {
+		remoteAddr = "[" + remoteAddr + "]"
+	}
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.Write([]byte(remoteAddr))
+}
+
+/*
+Expects a WebRTC SDP offer in the Request to give to an assigned
+snowflake proxy, which responds with the SDP answer to be sent in
+the HTTP response back to the client.
+*/
+func regHandler(w http.ResponseWriter, r *http.Request) {
+	// TODO: Maybe don't pass anything on path, since it will always be bidirectional
+	dir, _ := path.Split(path.Clean(r.URL.Path))
+	if dir != "/reg/" {
+		http.NotFound(w, r)
+		return
+	}
+	body, err := ioutil.ReadAll(r.Body)
+	if nil != err {
+		return
+		log.Println("Invalid data.")
+	}
+
+	// TODO: Get browser snowflake to talkto this appengine instance
+	// so it can reply with an answer, and not just the offer again :)
+	// TODO: Real facilitator which matches clients and snowflake proxies.
+	w.Write(body)
+}
+
+func init() {
+	http.HandleFunc("/robots.txt", robotsTxtHandler)
+	http.HandleFunc("/ip", ipHandler)
+	http.HandleFunc("/reg/", regHandler)
+	// if SNOWFLAKE_FACILITATOR == "" {
+	// panic("SNOWFLAKE_FACILITATOR empty; did you forget to edit config.go?")
+	// }
+}