Data channel message size limitations

src/js/adapter_factory.js

@@ -31,14 +31,6 @@ module.exports = function(dependencies, opts) {
   var logging = utils.log;
   var browserDetails = utils.detectBrowser(window);
 
-  // Export to the adapter global object visible in the browser.
-  var adapter = {
-    browserDetails: browserDetails,
-    extractVersion: utils.extractVersion,
-    disableLog: utils.disableLog,
-    disableWarnings: utils.disableWarnings
-  };
-
   // Uncomment the line below if you want logging to occur, including logging
   // for the switch statement below. Can also be turned on in the browser via
   // adapter.disableLog(false), but then logging from the switch statement below
@@ -52,6 +44,15 @@ module.exports = function(dependencies, opts) {
   var safariShim = require('./safari/safari_shim') || null;
   var commonShim = require('./common_shim') || null;
 
+  // Export to the adapter global object visible in the browser.
+  var adapter = {
+    browserDetails: browserDetails,
+    commonShim: commonShim,
+    extractVersion: utils.extractVersion,
+    disableLog: utils.disableLog,
+    disableWarnings: utils.disableWarnings
+  };
+
   // Shim browser if found.
   switch (browserDetails.browser) {
     case 'chrome':
@@ -74,6 +75,8 @@ module.exports = function(dependencies, opts) {
       chromeShim.shimGetSendersWithDtmf(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimMaxMessageSize(window);
+      commonShim.shimSendThrowTypeError(window);
       break;
     case 'firefox':
       if (!firefoxShim || !firefoxShim.shimPeerConnection ||
@@ -93,6 +96,8 @@ module.exports = function(dependencies, opts) {
       firefoxShim.shimRemoveStream(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimMaxMessageSize(window);
+      commonShim.shimSendThrowTypeError(window);
       break;
     case 'edge':
       if (!edgeShim || !edgeShim.shimPeerConnection || !options.shimEdge) {
@@ -109,6 +114,9 @@ module.exports = function(dependencies, opts) {
       edgeShim.shimReplaceTrack(window);
 
       // the edge shim implements the full RTCIceCandidate object.
+
+      commonShim.shimMaxMessageSize(window);
+      commonShim.shimSendThrowTypeError(window);
       break;
     case 'safari':
       if (!safariShim || !options.shimSafari) {
@@ -129,6 +137,8 @@ module.exports = function(dependencies, opts) {
       safariShim.shimCreateOfferLegacy(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimMaxMessageSize(window);
+      commonShim.shimSendThrowTypeError(window);
       break;
     default:
       logging('Unsupported browser!');

src/js/common_shim.js

@@ -162,5 +162,164 @@ module.exports = {
       }
       return nativeSetAttribute.apply(this, arguments);
     };
+  },
+
+  shimMaxMessageSize: function(window) {
+    if (window.RTCSctpTransport) {
+      return;
+    }
+    var browserDetails = utils.detectBrowser(window);
+
+    if (!('sctp' in window.RTCPeerConnection.prototype)) {
+      Object.defineProperty(window.RTCPeerConnection.prototype, 'sctp', {
+        get: function() {
+          return typeof this._sctp === 'undefined' ? null : this._sctp;
+        }
+      });
+    }
+
+    var sctpInDescription = function(description) {
+      var sections = SDPUtils.splitSections(description.sdp);
+      sections.shift();
+      return sections.some(function(mediaSection) {
+        var mLine = SDPUtils.parseMLine(mediaSection);
+        return mLine && mLine.kind === 'application'
+            && mLine.protocol.indexOf('SCTP') !== -1;
+      });
+    };
+
+    var getRemoteFirefoxVersion = function(description) {
+      // TODO: Is there a better solution for detecting Firefox?
+      var match = description.sdp.match(/mozilla...THIS_IS_SDPARTA-(\d+)/);
+      if (match === null || match.length < 2) {
+        return -1;
+      }
+      var version = parseInt(match[1], 10);
+      // Test for NaN (yes, this is ugly)
+      return version !== version ? -1 : version;
+    };
+
+    var getCanSendMaxMessageSize = function(remoteIsFirefox) {
+      // Every implementation we know can send at least 64 KiB.
+      // Note: Although Chrome is technically able to send up to 256 KiB, the
+      //       data does not reach the other peer reliably.
+      //       See: https://bugs.chromium.org/p/webrtc/issues/detail?id=8419
+      var canSendMaxMessageSize = 65536;
+      if (browserDetails.browser === 'firefox') {
+        if (browserDetails.version < 57) {
+          if (remoteIsFirefox === -1) {
+            // FF < 57 will send in 16 KiB chunks using the deprecated PPID
+            // fragmentation.
+            canSendMaxMessageSize = 16384;
+          } else {
+            // However, other FF (and RAWRTC) can reassemble PPID-fragmented
+            // messages. Thus, supporting ~2 GiB when sending.
+            canSendMaxMessageSize = 2147483637;
+          }
+        } else {
+          // Currently, all FF >= 57 will reset the remote maximum message size
+          // to the default value when a data channel is created at a later
+          // stage. :(
+          // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831
+          canSendMaxMessageSize =
+            browserDetails.version === 57 ? 65535 : 65536;
+        }
+      }
+      return canSendMaxMessageSize;
+    };
+
+    var getMaxMessageSize = function(description, remoteIsFirefox) {
+      // Note: 65536 bytes is the default value from the SDP spec. Also,
+      //       every implementation we know supports receiving 65536 bytes.
+      var maxMessageSize = 65536;
+
+      // FF 57 has a slightly incorrect default remote max message size, so
+      // we need to adjust it here to avoid a failure when sending.
+      // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1425697
+      if (browserDetails.browser === 'firefox'
+           && browserDetails.version === 57) {
+        maxMessageSize = 65535;
+      }
+
+      var match = SDPUtils.matchPrefix(description.sdp, 'a=max-message-size:');
+      if (match.length > 0) {
+        maxMessageSize = parseInt(match[0].substr(19), 10);
+      } else if (browserDetails.browser === 'firefox' &&
+                  remoteIsFirefox !== -1) {
+        // If the maximum message size is not present in the remote SDP and
+        // both local and remote are Firefox, the remote peer can receive
+        // ~2 GiB.
+        maxMessageSize = 2147483637;
+      }
+      return maxMessageSize;
+    };
+
+    var origSetRemoteDescription =
+        window.RTCPeerConnection.prototype.setRemoteDescription;
+    window.RTCPeerConnection.prototype.setRemoteDescription = function() {
+      var pc = this;
+      pc._sctp = null;
+
+      if (sctpInDescription(arguments[0])) {
+        // Check if the remote is FF.
+        var isFirefox = getRemoteFirefoxVersion(arguments[0]);
+
+        // Get the maximum message size the local peer is capable of sending
+        var canSendMMS = getCanSendMaxMessageSize(isFirefox);
+
+        // Get the maximum message size of the remote peer.
+        var remoteMMS = getMaxMessageSize(arguments[0], isFirefox);
+
+        // Determine final maximum message size
+        var maxMessageSize;
+        if (canSendMMS === 0 && remoteMMS === 0) {
+          maxMessageSize = Number.POSITIVE_INFINITY;
+        } else if (canSendMMS === 0 || remoteMMS === 0) {
+          maxMessageSize = Math.max(canSendMMS, remoteMMS);
+        } else {
+          maxMessageSize = Math.min(canSendMMS, remoteMMS);
+        }
+
+        // Create a dummy RTCSctpTransport object and the 'maxMessageSize'
+        // attribute.
+        var sctp = {};
+        Object.defineProperty(sctp, 'maxMessageSize', {
+          get: function() {
+            return maxMessageSize;
+          }
+        });
+        pc._sctp = sctp;
+      }
+
+      return origSetRemoteDescription.apply(pc, arguments);
+    };
+  },
+
+  shimSendThrowTypeError: function(window) {
+    // Note: Although Firefox >= 57 has a native implementation, the maximum
+    //       message size can be reset for all data channels at a later stage.
+    //       See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831
+
+    var origCreateDataChannel =
+      window.RTCPeerConnection.prototype.createDataChannel;
+    window.RTCPeerConnection.prototype.createDataChannel = function() {
+      var pc = this;
+      var dataChannel = origCreateDataChannel.apply(pc, arguments);
+      var origDataChannelSend = dataChannel.send;
+
+      // Patch 'send' method
+      dataChannel.send = function() {
+        var dc = this;
+        var data = arguments[0];
+        var length = data.length || data.size || data.byteLength;
+        if (length > pc.sctp.maxMessageSize) {
+          throw new DOMException('Message too large (can send a maximum of ' +
+            pc.sctp.maxMessageSize + ' bytes)', 'TypeError');
+        }
+        return origDataChannelSend.apply(dc, arguments);
+      };
+
+      return dataChannel;
+    };
   }
 };

test/e2e/expectations/chrome-beta

@@ -33,6 +33,20 @@ PASS getStats returns a Promise
 PASS getStats resolves the Promise with a Map(like)
 PASS getUserMedia navigator.getUserMedia exists
 PASS getUserMedia navigator.getUserMedia calls the callback
+PASS maxMessageSize sctp attribute exists
+PASS maxMessageSize sctp attribute is null before offer/answer
+PASS maxMessageSize sctp attribute is null if SCTP not negotiated
+PASS maxMessageSize sctp and maxMessageSize set if SCTP negotiated
+PASS maxMessageSize send largest possible single message
+PASS maxMessageSize throws an exception if the message is too large
+PASS maxMessageSize throws an exception if the message is too large (using a secondary data channel)
+PASS maxMessageSize is as expected for chrome>=0 and chrome>=0 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox<=56 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox>=57 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 64 KiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 1.5 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 2 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and Unlimited -> 65536
 PASS navigator.mediaDevices exists
 PASS navigator.mediaDevices is an EventTarget
 PASS navigator.mediaDevices implements the devicechange event

test/e2e/expectations/chrome-beta-no-experimental

@@ -33,6 +33,20 @@ PASS getStats returns a Promise
 PASS getStats resolves the Promise with a Map(like)
 PASS getUserMedia navigator.getUserMedia exists
 PASS getUserMedia navigator.getUserMedia calls the callback
+PASS maxMessageSize sctp attribute exists
+PASS maxMessageSize sctp attribute is null before offer/answer
+PASS maxMessageSize sctp attribute is null if SCTP not negotiated
+PASS maxMessageSize sctp and maxMessageSize set if SCTP negotiated
+PASS maxMessageSize send largest possible single message
+PASS maxMessageSize throws an exception if the message is too large
+PASS maxMessageSize throws an exception if the message is too large (using a secondary data channel)
+PASS maxMessageSize is as expected for chrome>=0 and chrome>=0 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox<=56 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox>=57 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 64 KiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 1.5 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 2 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and Unlimited -> 65536
 PASS navigator.mediaDevices exists
 PASS navigator.mediaDevices is an EventTarget
 PASS navigator.mediaDevices implements the devicechange event

test/e2e/expectations/chrome-stable

@@ -33,6 +33,20 @@ PASS getStats returns a Promise
 PASS getStats resolves the Promise with a Map(like)
 PASS getUserMedia navigator.getUserMedia exists
 PASS getUserMedia navigator.getUserMedia calls the callback
+PASS maxMessageSize sctp attribute exists
+PASS maxMessageSize sctp attribute is null before offer/answer
+PASS maxMessageSize sctp attribute is null if SCTP not negotiated
+PASS maxMessageSize sctp and maxMessageSize set if SCTP negotiated
+PASS maxMessageSize send largest possible single message
+PASS maxMessageSize throws an exception if the message is too large
+PASS maxMessageSize throws an exception if the message is too large (using a secondary data channel)
+PASS maxMessageSize is as expected for chrome>=0 and chrome>=0 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox<=56 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox>=57 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 64 KiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 1.5 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 2 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and Unlimited -> 65536
 PASS navigator.mediaDevices exists
 PASS navigator.mediaDevices is an EventTarget
 PASS navigator.mediaDevices implements the devicechange event

test/e2e/expectations/chrome-stable-no-experimental

@@ -33,6 +33,20 @@ PASS getStats returns a Promise
 PASS getStats resolves the Promise with a Map(like)
 PASS getUserMedia navigator.getUserMedia exists
 PASS getUserMedia navigator.getUserMedia calls the callback
+PASS maxMessageSize sctp attribute exists
+PASS maxMessageSize sctp attribute is null before offer/answer
+PASS maxMessageSize sctp attribute is null if SCTP not negotiated
+PASS maxMessageSize sctp and maxMessageSize set if SCTP negotiated
+PASS maxMessageSize send largest possible single message
+PASS maxMessageSize throws an exception if the message is too large
+PASS maxMessageSize throws an exception if the message is too large (using a secondary data channel)
+PASS maxMessageSize is as expected for chrome>=0 and chrome>=0 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox<=56 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox>=57 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 64 KiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 1.5 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 2 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and Unlimited -> 65536
 PASS navigator.mediaDevices exists
 PASS navigator.mediaDevices is an EventTarget
 PASS navigator.mediaDevices implements the devicechange event

test/e2e/expectations/chrome-unstable

@@ -33,6 +33,20 @@ PASS getStats returns a Promise
 PASS getStats resolves the Promise with a Map(like)
 PASS getUserMedia navigator.getUserMedia exists
 PASS getUserMedia navigator.getUserMedia calls the callback
+PASS maxMessageSize sctp attribute exists
+PASS maxMessageSize sctp attribute is null before offer/answer
+PASS maxMessageSize sctp attribute is null if SCTP not negotiated
+PASS maxMessageSize sctp and maxMessageSize set if SCTP negotiated
+PASS maxMessageSize send largest possible single message
+PASS maxMessageSize throws an exception if the message is too large
+PASS maxMessageSize throws an exception if the message is too large (using a secondary data channel)
+PASS maxMessageSize is as expected for chrome>=0 and chrome>=0 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox<=56 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and firefox>=57 -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 64 KiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 1.5 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and 2 GiB -> 65536
+PASS maxMessageSize is as expected for chrome>=0 and Unlimited -> 65536
 PASS navigator.mediaDevices exists
 PASS navigator.mediaDevices is an EventTarget
 PASS navigator.mediaDevices implements the devicechange event

test/e2e/expectations/firefox-beta

@@ -33,6 +33,20 @@ PASS getStats returns a Promise
 PASS getStats resolves the Promise with a Map(like)
 PASS getUserMedia navigator.getUserMedia exists
 PASS getUserMedia navigator.getUserMedia calls the callback
+PASS maxMessageSize sctp attribute exists
+PASS maxMessageSize sctp attribute is null before offer/answer
+PASS maxMessageSize sctp attribute is null if SCTP not negotiated
+PASS maxMessageSize sctp and maxMessageSize set if SCTP negotiated
+PASS maxMessageSize send largest possible single message
+PASS maxMessageSize throws an exception if the message is too large
+PASS maxMessageSize throws an exception if the message is too large (using a secondary data channel)
+PASS maxMessageSize is as expected for firefox>=58 and chrome>=0 -> 65536
+PASS maxMessageSize is as expected for firefox>=58 and firefox<=56 -> 65536
+PASS maxMessageSize is as expected for firefox>=58 and firefox>=57 -> 65536
+PASS maxMessageSize is as expected for firefox>=58 and 64 KiB -> 65536
+PASS maxMessageSize is as expected for firefox>=58 and 1.5 GiB -> 65536
+PASS maxMessageSize is as expected for firefox>=58 and 2 GiB -> 65536
+PASS maxMessageSize is as expected for firefox>=58 and Unlimited -> 65536
 PASS navigator.mediaDevices exists
 PASS navigator.mediaDevices is an EventTarget
 PASS navigator.mediaDevices implements the devicechange event

test/e2e/expectations/firefox-esr

@@ -33,6 +33,20 @@ PASS getStats returns a Promise
 PASS getStats resolves the Promise with a Map(like)
 PASS getUserMedia navigator.getUserMedia exists
 PASS getUserMedia navigator.getUserMedia calls the callback
+PASS maxMessageSize sctp attribute exists
+PASS maxMessageSize sctp attribute is null before offer/answer
+PASS maxMessageSize sctp attribute is null if SCTP not negotiated
+PASS maxMessageSize sctp and maxMessageSize set if SCTP negotiated
+PASS maxMessageSize send largest possible single message
+PASS maxMessageSize throws an exception if the message is too large
+PASS maxMessageSize throws an exception if the message is too large (using a secondary data channel)
+PASS maxMessageSize is as expected for firefox<=56 and chrome>=0 -> 16384
+PASS maxMessageSize is as expected for firefox<=56 and firefox<=56 -> 2147483637
+PASS maxMessageSize is as expected for firefox<=56 and firefox>=57 -> 1073741823
+PASS maxMessageSize is as expected for firefox<=56 and 64 KiB -> 16384
+PASS maxMessageSize is as expected for firefox<=56 and 1.5 GiB -> 16384
+PASS maxMessageSize is as expected for firefox<=56 and 2 GiB -> 16384
+PASS maxMessageSize is as expected for firefox<=56 and Unlimited -> 16384
 PASS navigator.mediaDevices exists
 PASS navigator.mediaDevices is an EventTarget
 PASS navigator.mediaDevices implements the devicechange event