move datachannel into ProxyPair as client, use hardcoded default Relay as fallback

proxy/snowflake.coffee

@@ -10,13 +10,15 @@ this must always act as the answerer.
 TODO(keroserene): Complete the websocket + webrtc ProxyPair
 ###
 
+DEFAULT_WEBSOCKET = '92.81.135.242:9901'
+
 if 'undefined' != typeof module && 'undefined' != typeof module.exports
   console.log 'not in browser.'
 else
   window.PeerConnection = window.RTCPeerConnection ||
                           window.mozRTCPeerConnection ||
                           window.webkitRTCPeerConnection
-  window.RTCIceCandidate = window.RTCIceCandidate || window.mozRTCIceCandidate;
+  window.RTCIceCandidate = window.RTCIceCandidate || window.mozRTCIceCandidate
   window.RTCSessionDescription = window.RTCSessionDescription ||
                                  window.mozRTCSessionDescription
 
@@ -25,7 +27,7 @@ Query =
   Parse a URL query string or application/x-www-form-urlencoded body. The
   return type is an object mapping string keys to string values. By design,
   this function doesn't support multiple values for the same named parameter,
-  for example "a=1&a=2&a=3"; the first definition always wins. Returns null on
+  for example 'a=1&a=2&a=3'; the first definition always wins. Returns null on
   error.
 
   Always decodes from UTF-8, not any other encoding.
@@ -61,8 +63,8 @@ Params =
   getBool: (query, param, defaultValue) ->
     val = query[param]
     return defaultValue if undefined == val
-    return true if "true" == val || "1" == val || "" == val
+    return true if 'true' == val || '1' == val || '' == val
-    return false if "false" == val || "0" == val
+    return false if 'false' == val || '0' == val
     return null
 
 
@@ -81,8 +83,8 @@ Params =
       result[name] = value if !(name in result)
     result
 
-  # Parse an address in the form "host:port". Returns an Object with keys "host"
+  # Parse an address in the form 'host:port'. Returns an Object with keys 'host'
-  # (String) and "port" (int). Returns null on error.
+  # (String) and 'port' (int). Returns null on error.
   parseAddress: (spec) ->
     m = null
     # IPv6 syntax.
@@ -104,191 +106,20 @@ Params =
     # elems = []
     # for k in x
       # elems.push(maybe_quote(k) + ': ' + repr(x[k]));
-    # return "{ " + elems.join(", ") + " }";
+    # return '{ ' + elems.join(', ') + ' }';
-  # } else if (typeof x === "string") {
+  # } else if (typeof x === 'string') {
     # return quote(x);
   # } else {
     # return x.toString();
-# safe_repr = (s) -> SAFE_LOGGING ? "[scrubbed]" : repr(s)
+# safe_repr = (s) -> SAFE_LOGGING ? '[scrubbed]' : repr(s)
-safe_repr = (s) -> SAFE_LOGGING ? "[scrubbed]" : JSON.stringify(s)
+safe_repr = (s) -> SAFE_LOGGING ? '[scrubbed]' : JSON.stringify(s)
 
 # HEADLESS is true if we are running not in a browser with a DOM.
 DEBUG = false
 if window && window.location
   query = Query.parse(window.location.search.substr(1))
-  DEBUG = Params.getBool(query, "debug", false)
+  DEBUG = Params.getBool(query, 'debug', false)
-HEADLESS = "undefined" == typeof(document)
+HEADLESS = 'undefined' == typeof(document)
-
-# TODO: Different ICE servers.
-config = {
-  iceServers: [
-    { urls: ["stun:stun.l.google.com:19302"] }
-  ]
-}
-
-# DOM elements
-$chatlog = null
-$send = null
-$input = null
-
-
-# TODO: Implement
-class Badge
-
-
-# Janky state machine
-MODE =
-  INIT:              0
-  WEBRTC_CONNECTING: 1
-  WEBRTC_READY:      2
-
-# Minimum viable snowflake for now - just 1 client.
-class Snowflake
-
-  # PeerConnection
-  pc: null
-  rateLimit: 0
-  proxyPairs: []
-  relayAddr: null
-  badge: null
-  $badge: null
-  MAX_NUM_CLIENTS = 1
-  CONNECTIONS_PER_CLIENT = 1
-  state: MODE.INIT
-
-  constructor: ->
-    if HEADLESS
-      # No badge
-    else if DEBUG
-      @$badge = debug_div
-    else
-      @badge = new Badge()
-      @$badgem = @badge.elem
-    @$badge.setAttribute("id", "snowflake-badge") if (@$badge)
-
-  # TODO: User-supplied for now, but should fetch from facilitator later.
-  setRelayAddr: (relayAddr) ->
-    addr = Params.parseAddress relayAddr
-    if !addr
-      log 'Invalid address spec. Try again.'
-      return false
-    @relayAddr = addr
-    log 'Using ' + relayAddr + ' as Relay.'
-    log "Input offer from the snowflake client:"
-    @beginWebRTC()
-    return true
-
-  # Initialize WebRTC PeerConnection
-  beginWebRTC: ->
-    log "Starting up Snowflake..."
-    @state = MODE.WEBRTC_CONNECTING
-
-    @pc = new PeerConnection(config, {
-      optional: [
-        { DtlsSrtpKeyAgreement: true }
-        { RtpDataChannels: false }
-      ]
-    })
-
-    @pc.onicecandidate = (evt) =>
-      # Browser sends a null candidate once the ICE gathering completes.
-      # In this case, it makes sense to send one copy-paste blob.
-      if null == evt.candidate
-        log "Finished gathering ICE candidates."
-        Signalling.send @pc.localDescription
-
-    # OnDataChannel triggered remotely from the client when connection succeeds.
-    @pc.ondatachannel = (dc) =>
-      console.log dc;
-      channel = dc.channel
-      log "Data Channel established..."
-      @prepareDataChannel channel
-
-  prepareDataChannel: (channel) ->
-    channel.onopen = =>
-      log "Data channel opened!"
-      @state = MODE.WEBRTC_READY
-      # This is the point when the WebRTC datachannel is done, so the next step
-      # is to establish websocket to the server.
-      @beginProxy(null, @relayAddr)
-    channel.onclose = =>
-      log "Data channel closed."
-      @state = MODE.INIT;
-      $chatlog.className = ""
-    channel.onerror = =>
-      log "Data channel error!"
-    channel.onmessage = (msg) =>
-      line = recv = msg.data
-      console.log(msg);
-      # Go sends only raw bytes...
-      if "[object ArrayBuffer]" == recv.toString()
-        bytes = new Uint8Array recv
-        line = String.fromCharCode.apply(null, bytes)
-      line = line.trim()
-      log "data: " + line
-
-  # Receive an SDP offer from client plugin.
-  receiveOffer: (desc) =>
-    sdp = new RTCSessionDescription desc
-    try
-      err = @pc.setRemoteDescription sdp
-    catch e
-      log "Invalid SDP message."
-      return false
-    log("SDP " + sdp.type + " successfully received.")
-    @sendAnswer() if 'offer' == sdp.type
-    true
-
-  sendAnswer: =>
-    next = (sdp) =>
-      log "webrtc: Answer ready."
-      @pc.setLocalDescription sdp
-    promise = @pc.createAnswer next
-    promise.then next if promise
-
-  # Poll facilitator when this snowflake can support more clients.
-  proxyMain: ->
-    if @proxyPairs.length >= @MAX_NUM_CLIENTS * @CONNECTIONS_PER_CLIENT
-      setTimeout(@proxyMain, @facilitator_poll_interval * 1000)
-      return
-
-    params = [["r", "1"]]
-    params.push ["transport", "websocket"]
-    params.push ["transport", "webrtc"]
-
-  beginProxy: (client, relay) ->
-    for i in [1..CONNECTIONS_PER_CLIENT]
-      @makeProxyPair client, relay
-
-  makeProxyPair: (client, relay) ->
-    pair = new ProxyPair(client, relay, @rate_limit);
-    @proxyPairs.push pair
-    pair.onCleanup = (event) =>
-      # Delete from the list of active proxy pairs.
-      @proxyPairs.splice(@proxy_pairs.indexOf(pair), 1)
-      @badge.endProxy() if @badge
-    try
-      pair.connectRelay()
-    catch err
-      log 'ERROR: ProxyPair exception while connecting.'
-      log err
-      return
-    @badge.beginProxy if @badge
-
-  cease: ->
-    while @proxyPairs.length > 0
-      @proxyPairs.pop().close()
-
-  disable: ->
-    log "Disabling Snowflake."
-    @cease()
-    @badge.disable() if @badge
-
-  die: ->
-    log "Snowflake died."
-    @cease()
-    @badge.die() if @badge
-
 
 DEFAULT_PORTS =
   http:  80
@@ -317,10 +148,10 @@ buildUrl = (scheme, host, port, path, params) ->
       path = '/' + path
     ###
     Slash is significant so we must protect it from encodeURIComponent, while
-    still encoding question mark and number sign. RFC 3986, section 3.3: "The
+    still encoding question mark and number sign. RFC 3986, section 3.3: 'The
     path is terminated by the first question mark ('?') or number sign ('#')
     character, or by the end of the URI. ... A path consists of a sequence of
-    path segments separated by a slash ('/') character."
+    path segments separated by a slash ('/') character.'
     ###
     path = path.replace /[^\/]+/, (m) ->
       encodeURIComponent m
@@ -339,59 +170,244 @@ makeWebsocket = (addr) ->
   # else
     # ws = new WebSocket url 'base64'
   ###
-  "User agents can use this as a hint for how to handle incoming binary data: if
+  'User agents can use this as a hint for how to handle incoming binary data: if
   the attribute is set to 'blob', it is safe to spool it to disk, and if it is
-  set to 'arraybuffer', it is likely more efficient to keep the data in memory."
+  set to 'arraybuffer', it is likely more efficient to keep the data in memory.'
   ###
   ws.binaryType = 'arraybuffer'
   ws
 
+# TODO: Different ICE servers.
+config = {
+  iceServers: [
+    { urls: ['stun:stun.l.google.com:19302'] }
+  ]
+}
 
+# DOM elements
+$chatlog = null
+$send = null
+$input = null
 
 # TODO: Implement
+class Badge
+
+# Janky state machine
+MODE =
+  INIT:              0
+  WEBRTC_CONNECTING: 1
+  WEBRTC_READY:      2
+
+# Minimum viable snowflake for now - just 1 client.
+class Snowflake
+
+  MAX_NUM_CLIENTS = 1
+  CONNECTIONS_PER_CLIENT = 1
+
+  relayAddr: null
+  # TODO: Actually support multiple ProxyPairs. (makes more sense once meek-
+  # signalling is ready)
+  proxyPairs: []
+  proxyPair: null
+
+  rateLimit: null  # TODO
+  badge: null
+  $badge: null
+  state: MODE.INIT
+
+  constructor: ->
+    if HEADLESS
+      # No badge
+    else if DEBUG
+      @$badge = debug_div
+    else
+      @badge = new Badge()
+      @$badgem = @badge.elem
+    @$badge.setAttribute('id', 'snowflake-badge') if (@$badge)
+
+  # TODO: User-supplied for now, but should fetch from facilitator later.
+  setRelayAddr: (relayAddr) ->
+    addr = Params.parseAddress relayAddr
+    if !addr
+      log 'Invalid address spec.'
+      return false
+    @relayAddr = addr
+    log 'Using ' + relayAddr + ' as Relay.'
+    @beginWebRTC()
+    log 'Input offer from the snowflake client:'
+    return true
+
+  # Initialize WebRTC PeerConnection
+  beginWebRTC: ->
+    log 'Starting up Snowflake...\n'
+    @state = MODE.WEBRTC_CONNECTING
+    for i in [1..CONNECTIONS_PER_CLIENT]
+      @makeProxyPair @relayAddr
+    @proxyPair = @proxyPairs[0]
+
+  # Receive an SDP offer from client plugin.
+  receiveOffer: (desc) =>
+    sdp = new RTCSessionDescription desc
+    try
+      err = @proxyPair.pc.setRemoteDescription sdp
+    catch e
+      log 'Invalid SDP message.'
+      return false
+    log('SDP ' + sdp.type + ' successfully received.')
+    @sendAnswer() if 'offer' == sdp.type
+    true
+
+  sendAnswer: =>
+    next = (sdp) =>
+      log 'webrtc: Answer ready.'
+      @proxyPair.pc.setLocalDescription sdp
+    promise = @proxyPair.pc.createAnswer next
+    promise.then next if promise
+
+  # Poll facilitator when this snowflake can support more clients.
+  proxyMain: ->
+    if @proxyPairs.length >= @MAX_NUM_CLIENTS * @CONNECTIONS_PER_CLIENT
+      setTimeout(@proxyMain, @facilitator_poll_interval * 1000)
+      return
+    params = [['r', '1']]
+    params.push ['transport', 'websocket']
+    params.push ['transport', 'webrtc']
+
+  makeProxyPair: (relay) ->
+    pair = new ProxyPair(null, relay, @rateLimit);
+    @proxyPairs.push pair
+    pair.onCleanup = (event) =>
+      # Delete from the list of active proxy pairs.
+      @proxyPairs.splice(@proxyPairs.indexOf(pair), 1)
+      @badge.endProxy() if @badge
+    try
+      pair.connectClient()
+    catch err
+      log 'ERROR: ProxyPair exception while connecting.'
+      log err
+      return
+    @badge.beginProxy if @badge
+
+  cease: ->
+    while @proxyPairs.length > 0
+      @proxyPairs.pop().close()
+
+  disable: ->
+    log 'Disabling Snowflake.'
+    @cease()
+    @badge.disable() if @badge
+
+  die: ->
+    log 'Snowflake died.'
+    @cease()
+    @badge.die() if @badge
+
+
+###
+Represents: client <-- webrtc --> snowflake <-- websocket --> relay
+###
 class ProxyPair
+  MAX_BUFFER: 10 * 1024 * 1024
+  pc: null
+  c2rSchedule: []
+  r2cSchedule: []
+  client: null  # WebRTC Data channel
+  relay: null   # websocket
+  running: true
+  flush_timeout_id: null
 
   constructor: (@clientAddr, @relayAddr, @rateLimit) ->
+    @c2rSchedule = []
+    @r2cSchedule = []
 
-  # Assumes WebRTC part is already connected.
+  connectClient: ->
-  # TODO: Put the webrtc stuff in ProxyPair, so that multiple webrtc connections
+    @pc = new PeerConnection config, {
-  # can be established.
+      optional: [
+        { DtlsSrtpKeyAgreement: true }
+        { RtpDataChannels: false }
+      ]}
+    @pc.onicecandidate = (evt) =>
+      # Browser sends a null candidate once the ICE gathering completes.
+      # In this case, it makes sense to send one copy-paste blob.
+      if null == evt.candidate
+        # TODO: Use a promise.all to tell Snowflake about all offers at once,
+        # once multiple proxypairs are supported.
+        log 'Finished gathering ICE candidates.'
+        Signalling.send @pc.localDescription
+    # OnDataChannel triggered remotely from the client when connection succeeds.
+    @pc.ondatachannel = (dc) =>
+      console.log dc;
+      channel = dc.channel
+      log 'Data Channel established...'
+      @prepareDataChannel channel
+      @client = channel
+
+  prepareDataChannel: (channel) ->
+    channel.onopen = =>
+      log 'Data channel opened!'
+      snowflake.state = MODE.WEBRTC_READY
+      # This is the point when the WebRTC datachannel is done, so the next step
+      # is to establish websocket to the server.
+      @connectRelay()
+    channel.onclose = =>
+      log 'Data channel closed.'
+      @state = MODE.INIT;
+      $chatlog.className = ''
+    channel.onerror = =>
+      log 'Data channel error!'
+    channel.onmessage = @onClientToRelayMessage
+
+  # Assumes WebRTC datachannel is connected.
   connectRelay: ->
-    log "Snowflake: connecting to relay"
+    log 'Connecting to relay...'
-
+    @relay = makeWebsocket @relayAddr
-    @relay = makeWebsocket(@relayAddr);
+    @relay.label = 'websocket-relay'
-    @relay.label = 'Relay'
     @relay.onopen = =>
-      log "Snowflake: " + ws.label + "connected"
+      log 'Relay ' + @relay.label + 'connected'
     @relay.onclose = @onClose
     @relay.onerror = @onError
     @relay.onmessage = @onRelayToClientMessage
 
-  onClientToRelayMessage: (event) ->
+  # WebRTC --> websocket
-    @c2r_schedule.push event.data
+  onClientToRelayMessage: (msg) =>
+    line = recv = msg.data
+    console.log msg
+    # Go sends only raw bytes...
+    if '[object ArrayBuffer]' == recv.toString()
+      bytes = new Uint8Array recv
+      line = String.fromCharCode.apply(null, bytes)
+    line = line.trim()
+    log 'WebRTC-->websocket data: ' + line
+    @c2rSchedule.push recv
     @flush()
 
-  onRelayToClientMessage: (event) ->
+  # websocket --> WebRTC
-    @r2c_schedule.push event.data
+  onRelayToClientMessage: (event) =>
+    @r2cSchedule.push event.data
+    log 'websocket-->WebRTC data: ' + event.data
     @flush()
 
-  onClose: (event) ->
+  onClose: (event) =>
     ws = event.target
     log(ws.label + ': closed.')
     @flush()
     @maybeCleanup()
 
-  onError: (event) ->
+  onError: (event) =>
     ws = event.target
     log ws.label + ': error.'
-    this.close();
+    @close()
     # we can't rely on onclose_callback to cleanup, since one common error
     # case is when the client fails to connect and the relay never starts.
     # in that case close() is a NOP and onclose_callback is never called.
     @maybeCleanup()
 
+  webrtcIsReady: -> null != @client && 'open' == @client.readyState
   isOpen:   (ws) -> undefined != ws && WebSocket.OPEN   == ws.readyState
   isClosed: (ws) -> undefined == ws || WebSocket.CLOSED == ws.readyState
+  close: ->
+    @client.close() if !(isClosed @client)
+    @relay.close() if !(isClosed @relay)
 
   maybeCleanup: ->
     if @running && @isClosed(client) && @isClosed @relay 
@@ -402,67 +418,45 @@ class ProxyPair
 
   # Send as much data as the rate limit currently allows.
   flush: ->
-  ###
     clearTimeout @flush_timeout_id if @flush_timeout_id
     @flush_timeout_id = null
     busy = true
-    checkChunks = ->
+    checkChunks = =>
       busy = false
-      # if @isOpen @clientthis.client_s) &&
+      # websocket --> WebRTC
-          # this.client_s.bufferedAmount < MAX_BUFFER &&
+      if @webrtcIsReady() && @client.bufferedAmount < @MAX_BUFFER && @r2cSchedule.length > 0
-          # this.r2c_schedule.length > 0) {
+        chunk = @r2cSchedule.shift()
-        # chunk = this.r2c_schedule.shift();
+        # this.rate_limit.update(chunk.length)
-        # this.rate_limit.update(chunk.length);
+        @client.send chunk
-        # this.client_s.send(chunk);
+        busy = true
-        # busy = true;
+      # WebRTC --> websocket
-      #
+      if (@isOpen @relay) && (@relay.bufferedAmount < @MAX_BUFFER) && @c2rSchedule.length > 0
-      if @isOpen @relay &&
+        chunk = @c2rSchedule.shift()
-        @relay.bufferedAmount < MAX_BUFFER &&
+        # @rate_limit.update chunk.length
-        @c2r_schedule.length > 0
-        chunk = @c2r_schedule.shift()
-        @rate_limit.update chunk.length
         @relay.send chunk
         busy = true
-    checkChunks() while busy && !@rate_limit.is_limited()
+    checkChunks() while busy  # && !@rate_limit.is_limited()
 
-    if @isClosed @relay &&
+    # TODO: rate limiting stuff
-        # !isClosed(this.client_s) &&
+    # if @r2cSchedule.length > 0 || (@client) && @client.bufferedAmount > 0) || @c2rSchedule.length > 0 || (@isOpen(@relay) && @relay.bufferedAmount > 0)
-        # @client_s.bufferedAmount === 0 &&
+      # @flush_timeout_id = setTimeout @flush, @rate_limit.when() * 1000
-        @r2c_schedule.length == 0
-      # log("Client: closing.");
-      # this.client_s.close();
-      # if (is_closed(this.client_s) &&
-        # !is_closed(this.relay_s) &&
-        # this.relay_s.bufferedAmount === 0 &&
-        # this.c2r_schedule.length === 0) {
-      # log("Relay: closing.");
-      # this.relay_s.close();
-    # }
 
-
-    while busy && !@rate_limit.is_limited()
-
-    if this.r2c_schedule.length > 0 ||
-      (@isOpen(@client) && @client.bufferedAmount > 0) ||
-      @c2r_schedule.length > 0 ||
-      (@isOpen(@relay) && @relay.bufferedAmount > 0)
-      @flush_timeout_id = setTimeout @flush, @rate_limit.when() * 1000
-  ###
 #
 ## -- DOM & Input Functionality -- ##
 #
 snowflake = null
 
 welcome = ->
-  log "== snowflake browser proxy =="
+  log '== snowflake browser proxy =='
-  log "Input desired relay address:"
+  log 'Input desired relay address:'
 
 # Log to the message window.
 log = (msg) ->
-  $chatlog.value += msg + "\n"
   console.log msg
   # Scroll to latest
-  $chatlog.scrollTop = $chatlog.scrollHeight
+  if $chatlog
+    $chatlog.value += msg + '\n'
+    $chatlog.scrollTop = $chatlog.scrollHeight
 
 Interface =
   # Local input from keyboard into message window.
@@ -471,44 +465,46 @@ Interface =
     switch snowflake.state
       when MODE.INIT
         # Set target relay.
-        snowflake.setRelayAddr msg
+        if !(snowflake.setRelayAddr msg)
+          log 'Defaulting to websocket relay at ' + DEFAULT_WEBSOCKET
+          snowflake.setRelayAddr DEFAULT_WEBSOCKET
       when MODE.WEBRTC_CONNECTING
         Signalling.receive msg
       when MODE.WEBRTC_READY
-        log "No input expected - WebRTC connected."
+        log 'No input expected - WebRTC connected.'
         # data = msg
         # log(data)
         # channel.send(data)
       else
-        log "ERROR: " + msg
+        log 'ERROR: ' + msg
-    $input.value = ""
+    $input.value = ''
     $input.focus()
 
 # Signalling channel - just tells user to copy paste to the peer.
 # Eventually this should go over the facilitator.
 Signalling =
   send: (msg) ->
-    log "---- Please copy the below to peer ----\n"
+    log '---- Please copy the below to peer ----\n'
     log JSON.stringify(msg)
-    log "\n"
+    log '\n'
 
   receive: (msg) ->
-    recv = ""
+    recv = ''
     try
       recv = JSON.parse msg
     catch e
-      log "Invalid JSON."
+      log 'Invalid JSON.'
       return
     desc = recv['sdp']
     if !desc
-      log "Invalid SDP."
+      log 'Invalid SDP.'
       return false
     snowflake.receiveOffer recv if desc
 
 init = ->
 
   $chatlog = document.getElementById('chatlog')
-  $chatlog.value = ""
+  $chatlog.value = ''
 
   $send = document.getElementById('send')
   $send.onclick = Interface.acceptInput

proxy/snowflake_test.coffee

@@ -188,7 +188,14 @@ testParseQueryString = ->
     else
       fail test.qs, test.expected, actual
 
+testProxyPair = ->
+  announce 'testProxyPair'
+  addr = Params.parseAddress '0.0.0.0:35302'
+  console.log addr
+  pair = new ProxyPair(null, addr, 0)
+  pair.connectRelay()
 
 testBuildUrl()
 testParseCookieString()
 testParseQueryString()
+# testProxyPair()