Update the call when the network route changes

webrtc/call/call.cc

Index: webrtc/call/call.cc
diff --git a/webrtc/call/call.cc b/webrtc/call/call.cc
index 91c27c80ad99f16805b80ad45b2916c60812748d..a50c3e5cedd6bcd065c22d0f2ee6127ac9646ae7 100644
--- a/webrtc/call/call.cc
+++ b/webrtc/call/call.cc
@@ -89,6 +89,10 @@ class Call : public webrtc::Call, public PacketReceiver,
 
   void SignalChannelNetworkState(MediaType media, NetworkState state) override;
 
+  void OnNetworkRouteChanged(
+      const std::string& transport_name,
+      const cricket::NetworkRoute& network_route) override;
+
   void OnSentPacket(const rtc::SentPacket& sent_packet) override;
 
   // Implements BitrateObserver.
@@ -102,7 +106,6 @@ class Call : public webrtc::Call, public PacketReceiver,
                             const uint8_t* packet,
                             size_t length,
                             const PacketTime& packet_time);
-
   void ConfigureSync(const std::string& sync_group)
       EXCLUSIVE_LOCKS_REQUIRED(receive_crit_);
 
@@ -170,6 +173,8 @@ class Call : public webrtc::Call, public PacketReceiver,
   int64_t pacer_bitrate_sum_kbits_ GUARDED_BY(&bitrate_crit_);
   int64_t num_bitrate_updates_ GUARDED_BY(&bitrate_crit_);
 
+  std::map<std::string, cricket::NetworkRoute> network_routes_;
+
   VieRemb remb_;
   const std::unique_ptr<CongestionController> congestion_controller_;
 
@@ -591,6 +596,38 @@ void Call::SignalChannelNetworkState(MediaType media, NetworkState state) {
   }
 }
 
+// TODO(honghaiz): Add tests for this method.
+void Call::OnNetworkRouteChanged(const std::string& transport_name,
+                                 const cricket::NetworkRoute& network_route) {
+  RTC_DCHECK(configuration_thread_checker_.CalledOnValidThread());
+  // Check if the network route is connected.
+  if (!network_route.connected) {
+    LOG(LS_INFO) << "Transport " << transport_name << " is disconnected";
+    // TODO(honghaiz): Perhaps it should stop sending until a connected route is
+    // established.

[stefan-webrtc, 2016/03/31 07:17:05]

This makes me wonder if this method should replace SignalChannelNetworkState
too? Or should we differentiate between a NetworkRoute which isn't .connected
and one which is "down" (as set by SignalChannelNetworkState)?

[honghaiz3, 2016/03/31 17:42:52]

Currently SignalChannelNetworkState is triggered by
transport_channel::writable() and EWOULDBLOCK, but this is signalled by selected
candidate pair changed. 
So I think this should not replace SignalChannelNetworkState. Perhaps this
(network disconnect) need not be handled here. Instead, it should be handled in
the SignalChannelNetworkState (network up and down).
It is also possible to merge them together, but this will need some more
discussion. Peter and I discussed the plan to refactor the SignalReadyToSend
(which fires SignalChannelNetworkState). We can consider merging these two
methods along with that work. For now I will just leave a TODO here.

[stefan-webrtc, 2016/04/01 08:08:38]

Sounds good, it would be nice to keep the number of "network has changed in some
way" signals down...

[honghaiz3, 2016/04/01 22:21:07]

Not sure what you mean by that. 

+    return;
+  }
+
+  // Check whether the network route has changed on each transport.
+  auto result =
+      network_routes_.insert(std::make_pair(transport_name, network_route));
+  auto kv = result.first;
+  bool inserted = result.second;
+  if (inserted) {
+    // No need to reset BWE if this is the first time the network connects.
+    return;
+  }
+  bool changed = kv->second != network_route;
+  if (changed) {
+    kv->second = network_route;
+    LOG(LS_INFO) << "Network route changed on transport " << transport_name
+                 << ": new local network id " << network_route.local_network_id
+                 << " new remote network id "
+                 << network_route.remote_network_id;
+    // TODO(stefan@): Update the BWE bitrates.

[stefan-webrtc, 2016/03/31 07:17:05]

TODO(holmer) preferred

[honghaiz3, 2016/03/31 17:42:52]

Done.

+  }
+}
+
 void Call::UpdateAggregateNetworkState() {
   RTC_DCHECK(configuration_thread_checker_.CalledOnValidThread());