Report metrics about negotiated ciphers.

talk/app/webrtc/webrtcsession.cc

 /*
  * libjingle
  * Copyright 2012 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 1375 matching lines @@
   }
 }
 
 void WebRtcSession::OnTransportCompleted(cricket::Transport* transport) {
   ASSERT(signaling_thread()->IsCurrent());
   PeerConnectionInterface::IceConnectionState old_state = ice_connection_state_;
   SetIceConnectionState(PeerConnectionInterface::kIceConnectionCompleted);
   // Only report once when Ice connection is completed.
   if (old_state != PeerConnectionInterface::kIceConnectionCompleted) {
     ReportBestConnectionState(transport);
+    ReportNegotiatedCiphers(transport);

[guoweis_webrtc, 2015/06/08 17:09:11]

Both ReportBestConnectionState and ReportNegotiatedCiphers call GetStats
internally. I could imagine there might be other reporting in the future.
Suggest to have the GetStats outside and pass the state into each function.

[joachim, 2015/06/08 20:58:40]

Done.

   }
 }
 
 void WebRtcSession::OnTransportFailed(cricket::Transport* transport) {
   ASSERT(signaling_thread()->IsCurrent());
   SetIceConnectionState(PeerConnectionInterface::kIceConnectionFailed);
 }
 
 void WebRtcSession::OnTransportProxyCandidatesReady(
     cricket::TransportProxy* proxy, const cricket::Candidates& candidates) {
@@ skipping 491 matching lines @@
                  AF_INET6) {
         metrics_observer_->IncrementCounter(kBestConnections_IPv6);
       } else {
         ASSERT(false);
       }
       return;
     }
   }
 }
 
+void WebRtcSession::ReportNegotiatedCiphers(cricket::Transport* transport) {
+  if (!metrics_observer_ || !dtls_enabled_) {
+    return;
+  }
+
+  cricket::TransportStats stats;
+  if (!transport->GetStats(&stats) || stats.channel_stats.empty()) {
+    return;
+  }
+
+  const std::string& srtp_cipher = stats.channel_stats[0].srtp_cipher;
+  const std::string& ssl_cipher = stats.channel_stats[0].ssl_cipher;
+  if (srtp_cipher.empty() || ssl_cipher.empty()) {
+    return;
+  }
+
+  metrics_observer_->CiphersNegotiated(stats.content_name,
+                                       srtp_cipher, ssl_cipher);
+}
+
 }  // namespace webrtc