Fixing bug that results in incorrect ICE role with ICE lite endpoints.

webrtc/p2p/base/transportcontroller.cc

 /*
  *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 584 matching lines @@
   // Older versions of Chrome expect the ICE role to be re-determined when an
   // ICE restart occurs, and also don't perform conflict resolution correctly,
   // so for now we can't safely stop doing this, unless the application opts in
   // by setting |redetermine_role_on_ice_restart_| to false.
   // See: https://bugs.chromium.org/p/chromium/issues/detail?id=628676
   // TODO(deadbeef): Remove this when these old versions of Chrome reach a low
   // enough population.
   if (redetermine_role_on_ice_restart_ && transport->local_description() &&
       IceCredentialsChanged(transport->local_description()->ice_ufrag,
                             transport->local_description()->ice_pwd,
-                            tdesc.ice_ufrag, tdesc.ice_pwd)) {
+                            tdesc.ice_ufrag, tdesc.ice_pwd) &&
+      // Don't change the ICE role if the remote endpoint is ICE lite; we
+      // should always be controlling in that case.

[Zhi Huang, 2017/04/12 21:32:59]

Extreme minor thing. Since we are changing the ice_role here, it feels more
straightforward by saying "Change the ICE role if the remote endpoint is not ICE
lite" or keeping the comment but change the code to ice_mode != ICEMODE_LITE.

[Taylor Brandstetter, 2017/04/20 07:23:53]

Done.

+      (!transport->remote_description() ||
+       transport->remote_description()->ice_mode == ICEMODE_FULL)) {
     IceRole new_ice_role =
         (action == CA_OFFER) ? ICEROLE_CONTROLLING : ICEROLE_CONTROLLED;
     SetIceRole(new_ice_role);
   }
 
   LOG(LS_INFO) << "Set local transport description on " << transport_name;
   return transport->SetLocalTransportDescription(tdesc, action, err);
 }
 
 bool TransportController::SetRemoteTransportDescription_n(
@@ skipping 267 matching lines @@
         RTC_FROM_HERE, this, MSG_ICEGATHERINGSTATE,
         new rtc::TypedMessageData<IceGatheringState>(new_gathering_state));
   }
 }
 
 void TransportController::OnDtlsHandshakeError(rtc::SSLHandshakeError error) {
   SignalDtlsHandshakeError(error);
 }
 
 }  // namespace cricket