Use "UDP/TLS/RTP/SAVPF" profile in offer when DTLS-SRTP is used.

talk/session/media/mediasession.cc

 /*
  * libjingle
  * Copyright 2004 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 45 matching lines @@
 
 using rtc::scoped_ptr;
 
 // RTP Profile names
 // http://www.iana.org/assignments/rtp-parameters/rtp-parameters.xml
 // RFC4585
 const char kMediaProtocolAvpf[] = "RTP/AVPF";
 // RFC5124
 const char kMediaProtocolDtlsSavpf[] = "UDP/TLS/RTP/SAVPF";
 
-// This should be replaced by "UDP/TLS/RTP/SAVPF", but we need to support it for
-// now to be compatible with previous Chrome versions.
+// We always generate offers with "UDP/TLS/RTP/SAVPF" when using DTLS-SRTP,
+// but we tolerate "RTP/SAVPF" in offers we receive, for compatibility.
 const char kMediaProtocolSavpf[] = "RTP/SAVPF";
 
 const char kMediaProtocolRtpPrefix[] = "RTP/";
 
 const char kMediaProtocolSctp[] = "SCTP";
 const char kMediaProtocolDtlsSctp[] = "DTLS/SCTP";
 const char kMediaProtocolUdpDtlsSctp[] = "UDP/DTLS/SCTP";
 const char kMediaProtocolTcpDtlsSctp[] = "TCP/DTLS/SCTP";
 
 static bool IsMediaContentOfType(const ContentInfo* content,
@@ skipping 529 matching lines @@
                          const std::string& content_name) {
   bool is_rtp = false;
   ContentInfo* content = sdesc->GetContentByName(content_name);
   if (IsMediaContent(content)) {
     MediaContentDescription* media_desc =
         static_cast<MediaContentDescription*>(content->description);
     if (!media_desc) {
       return false;
     }
     is_rtp = media_desc->protocol().empty() ||
-             rtc::starts_with(media_desc->protocol().data(),
-                                    kMediaProtocolRtpPrefix);
+             (media_desc->protocol().find(cricket::kMediaProtocolRtpPrefix) !=
+              std::string::npos);
   }
   return is_rtp;
 }
 
 // Updates the crypto parameters of the |sdesc| according to the given
 // |bundle_group|. The crypto parameters of all the contents within the
 // |bundle_group| should be updated to use the common subset of the
 // available cryptos.
 static bool UpdateCryptoParamsForBundle(const ContentGroup& bundle_group,
                                         SessionDescription* sdesc) {
@@ skipping 411 matching lines @@
 
   // Since not all applications serialize and deserialize the media protocol,
   // we will have to accept |protocol| to be empty.
   return protocol == kMediaProtocolAvpf || protocol.empty() ||
       protocol == kMediaProtocolSavpf ||
       (protocol == kMediaProtocolDtlsSavpf && secure_transport);
 }
 
 static void SetMediaProtocol(bool secure_transport,
                              MediaContentDescription* desc) {
-  if (!desc->cryptos().empty() || secure_transport)
+  if (!desc->cryptos().empty())
     desc->set_protocol(kMediaProtocolSavpf);
+  else if (secure_transport)
+    desc->set_protocol(kMediaProtocolDtlsSavpf);
   else
     desc->set_protocol(kMediaProtocolAvpf);
 }
 
 // Gets the TransportInfo of the given |content_name| from the
 // |current_description|. If doesn't exist, returns a new one.
 static const TransportDescription* GetTransportDescription(
     const std::string& content_name,
     const SessionDescription* current_description) {
   const TransportDescription* desc = NULL;
@@ skipping 883 matching lines @@
   } else if (channel_name == GICE_CHANNEL_NAME_DATA_RTP ||
              channel_name == GICE_CHANNEL_NAME_DATA_RTCP) {
     *media_type = MEDIA_TYPE_DATA;
     return true;
   }
 
   return false;
 }
 
 }  // namespace cricket