Only generate one CNAME per PeerConnection.

webrtc/pc/mediasession.cc

 /*
  *  Copyright 2004 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 193 matching lines @@
        i != cryptos.end(); ++i) {
     if (rtc::CS_AES_CM_128_HMAC_SHA1_80 == i->cipher_suite ||
         (rtc::CS_AES_CM_128_HMAC_SHA1_32 == i->cipher_suite && audio &&
          !bundle)) {
       return CreateCryptoParams(i->tag, i->cipher_suite, crypto);
     }
   }
   return false;
 }
 
-static const StreamParams* FindFirstStreamParamsByCname(
-    const StreamParamsVec& params_vec,
-    const std::string& cname) {
-  for (StreamParamsVec::const_iterator it = params_vec.begin();
-       it != params_vec.end(); ++it) {
-    if (cname == it->cname)
-      return &*it;
-  }
-  return NULL;
-}
-
-// Generates a new CNAME or the CNAME of an already existing StreamParams
-// if a StreamParams exist for another Stream in streams with sync_label
-// sync_label.
-static bool GenerateCname(const StreamParamsVec& params_vec,
-                          const MediaSessionOptions::Streams& streams,
-                          const std::string& synch_label,
-                          std::string* cname) {
-  ASSERT(cname != NULL);
-  if (!cname)
-    return false;
-
-  // Check if a CNAME exist for any of the other synched streams.
-  for (MediaSessionOptions::Streams::const_iterator stream_it = streams.begin();
-       stream_it != streams.end() ; ++stream_it) {
-    if (synch_label != stream_it->sync_label)
-      continue;
-
-    // groupid is empty for StreamParams generated using
-    // MediaSessionDescriptionFactory.
-    const StreamParams* param = GetStreamByIds(params_vec, "", stream_it->id);
-    if (param) {
-      *cname = param->cname;
-      return true;
-    }
-  }
-  // No other stream seems to exist that we should sync with.
-  // Generate a random string for the RTCP CNAME, as stated in RFC 6222.
-  // This string is only used for synchronization, and therefore is opaque.
-  do {
-    if (!rtc::CreateRandomString(16, cname)) {
-      ASSERT(false);
-      return false;
-    }
-  } while (FindFirstStreamParamsByCname(params_vec, *cname));
-
-  return true;
-}
-
 // Generate random SSRC values that are not already present in |params_vec|.
 // The generated values are added to |ssrcs|.
 // |num_ssrcs| is the number of the SSRC will be generated.
 static void GenerateSsrcs(const StreamParamsVec& params_vec,
                           int num_ssrcs,
                           std::vector<uint32_t>* ssrcs) {
   for (int i = 0; i < num_ssrcs; i++) {
     uint32_t candidate;
     do {
       candidate = rtc::CreateRandomNonZeroId();
@@ skipping 164 matching lines @@
 
 static bool IsSctp(const MediaContentDescription* desc) {
   return ((desc->protocol() == kMediaProtocolSctp) ||
           (desc->protocol() == kMediaProtocolDtlsSctp));
 }
 
 // Adds a StreamParams for each Stream in Streams with media type
 // media_type to content_description.
 // |current_params| - All currently known StreamParams of any media type.
 template <class C>
-static bool AddStreamParams(
-    MediaType media_type,
-    const MediaSessionOptions::Streams& streams,
-    StreamParamsVec* current_streams,
-    MediaContentDescriptionImpl<C>* content_description,
-    const bool add_legacy_stream) {
+static bool AddStreamParams(MediaType media_type,
+                            const MediaSessionOptions& options,
+                            StreamParamsVec* current_streams,
+                            MediaContentDescriptionImpl<C>* content_description,
+                            const bool add_legacy_stream) {
   const bool include_rtx_streams =
       ContainsRtxCodec(content_description->codecs());
 
+  const MediaSessionOptions::Streams& streams = options.streams;
   if (streams.empty() && add_legacy_stream) {
     // TODO(perkj): Remove this legacy stream when all apps use StreamParams.
     std::vector<uint32_t> ssrcs;
     if (IsSctp(content_description)) {
       GenerateSctpSids(*current_streams, &ssrcs);
     } else {
       int num_ssrcs = include_rtx_streams ? 2 : 1;
       GenerateSsrcs(*current_streams, num_ssrcs, &ssrcs);
     }
     if (include_rtx_streams) {
@@ skipping 10 matching lines @@
        stream_it != streams.end(); ++stream_it) {
     if (stream_it->type != media_type)
       continue;  // Wrong media type.
 
     const StreamParams* param =
         GetStreamByIds(*current_streams, "", stream_it->id);
     // groupid is empty for StreamParams generated using
     // MediaSessionDescriptionFactory.
     if (!param) {
       // This is a new stream.
-      // Get a CNAME. Either new or same as one of the other synched streams.
-      std::string cname;
-      if (!GenerateCname(*current_streams, streams, stream_it->sync_label,
-                         &cname)) {
-        return false;
-      }
-
       std::vector<uint32_t> ssrcs;
       if (IsSctp(content_description)) {
         GenerateSctpSids(*current_streams, &ssrcs);
       } else {
         GenerateSsrcs(*current_streams, stream_it->num_sim_layers, &ssrcs);
       }
       StreamParams stream_param;
       stream_param.id = stream_it->id;
       // Add the generated ssrc.
       for (size_t i = 0; i < ssrcs.size(); ++i) {
         stream_param.ssrcs.push_back(ssrcs[i]);
       }
       if (stream_it->num_sim_layers > 1) {
         SsrcGroup group(kSimSsrcGroupSemantics, stream_param.ssrcs);
         stream_param.ssrc_groups.push_back(group);
       }
       // Generate extra ssrcs for include_rtx_streams case.
       if (include_rtx_streams) {
         // Generate an RTX ssrc for every ssrc in the group.
         std::vector<uint32_t> rtx_ssrcs;
         GenerateSsrcs(*current_streams, static_cast<int>(ssrcs.size()),
                       &rtx_ssrcs);
         for (size_t i = 0; i < ssrcs.size(); ++i) {
           stream_param.AddFidSsrc(ssrcs[i], rtx_ssrcs[i]);
         }
         content_description->set_multistream(true);
       }
-      stream_param.cname = cname;
+      stream_param.cname = options.rtcp_cname;
       stream_param.sync_label = stream_it->sync_label;
       content_description->AddStream(stream_param);
 
       // Store the new StreamParams in current_streams.
       // This is necessary so that we can use the CNAME for other media types.
       current_streams->push_back(stream_param);
     } else {
       content_description->AddStream(*param);
     }
   }
@@ skipping 223 matching lines @@
   if (secure_policy == SEC_REQUIRED) {
     offer->set_crypto_required(CT_SDES);
   }
   offer->set_rtcp_mux(options.rtcp_mux_enabled);
   if (offer->type() == cricket::MEDIA_TYPE_VIDEO) {
     offer->set_rtcp_reduced_size(true);
   }
   offer->set_multistream(options.is_muc);
   offer->set_rtp_header_extensions(rtp_extensions);
 
-  if (!AddStreamParams(
-          offer->type(), options.streams, current_streams,
-          offer, add_legacy_stream)) {
+  if (!AddStreamParams(offer->type(), options, current_streams, offer,
+                       add_legacy_stream)) {
     return false;
   }
 
 #ifdef HAVE_SRTP
   if (secure_policy != SEC_DISABLED) {
     if (current_cryptos) {
       AddMediaCryptos(*current_cryptos, offer);
     }
     if (offer->cryptos().empty()) {
       if (!CreateMediaCryptos(crypto_suites, offer)) {
@@ skipping 296 matching lines @@
       }
       answer->AddCrypto(crypto);
     }
   }
 
   if (answer->cryptos().empty() &&
       (offer->crypto_required() == CT_SDES || sdes_policy == SEC_REQUIRED)) {
     return false;
   }
 
-  if (!AddStreamParams(
-          answer->type(), options.streams, current_streams,
-          answer, add_legacy_stream)) {
+  if (!AddStreamParams(answer->type(), options, current_streams, answer,
+                       add_legacy_stream)) {
     return false;  // Something went seriously wrong.
   }
 
   // Make sure the answer media content direction is per default set as
   // described in RFC3264 section 6.1.
   switch (offer->direction()) {
     case MD_INACTIVE:
       answer->set_direction(MD_INACTIVE);
       break;
     case MD_SENDONLY:
@@ skipping 942 matching lines @@
       GetFirstMediaContentDescription(sdesc, MEDIA_TYPE_VIDEO));
 }
 
 const DataContentDescription* GetFirstDataContentDescription(
     const SessionDescription* sdesc) {
   return static_cast<const DataContentDescription*>(
       GetFirstMediaContentDescription(sdesc, MEDIA_TYPE_DATA));
 }
 
 }  // namespace cricket