Support encrypted RTP extensions (RFC 6904)

webrtc/pc/webrtcsdp.cc

 /*
  *  Copyright 2011 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 1193 matching lines @@
   if (!GetValue(fields[0], kAttributeExtmap, &value_direction, error)) {
     return false;
   }
   std::vector<std::string> sub_fields;
   rtc::split(value_direction, kSdpDelimiterSlash, &sub_fields);
   int value = 0;
   if (!GetValueFromString(line, sub_fields[0], &value, error)) {
     return false;
   }
 
-  *extmap = RtpExtension(uri, value);
+  bool encrypted = false;
+  if (uri == RtpExtension::kEncryptHeaderExtensionsUri) {
+    // RFC 6904
+    // a=extmap:<value["/"<direction>] urn:ietf:params:rtp-hdrext:encrypt \
+    //     <URI> <extensionattributes>
+    const size_t expected_min_fields_encrypted = expected_min_fields + 1;
+    if (fields.size() < expected_min_fields_encrypted) {
+      return ParseFailedExpectMinFieldNum(line, expected_min_fields_encrypted,
+          error);
+    }
+
+    encrypted = true;
+    uri = fields[2];
+    if (uri == RtpExtension::kEncryptHeaderExtensionsUri) {
+      return ParseFailed(line, "Recursive encrypted header.", error);
+    }
+  }
+
+  *extmap = RtpExtension(uri, value, encrypted);
   return true;
 }
 
 void BuildMediaDescription(const ContentInfo* content_info,
                            const TransportInfo* transport_info,
                            const MediaType media_type,
                            const std::vector<Candidate>& candidates,
                            bool unified_plan_sdp,
                            std::string* message) {
   RTC_DCHECK(message != NULL);
@@ skipping 222 matching lines @@
 void BuildRtpContentAttributes(const MediaContentDescription* media_desc,
                                const MediaType media_type,
                                bool unified_plan_sdp,
                                std::string* message) {
   std::ostringstream os;
   // RFC 5285
   // a=extmap:<value>["/"<direction>] <URI> <extensionattributes>
   // The definitions MUST be either all session level or all media level. This
   // implementation uses all media level.
   for (size_t i = 0; i < media_desc->rtp_header_extensions().size(); ++i) {
+    const RtpExtension& extension = media_desc->rtp_header_extensions()[i];
     InitAttrLine(kAttributeExtmap, &os);
-    os << kSdpDelimiterColon << media_desc->rtp_header_extensions()[i].id
-       << kSdpDelimiterSpace << media_desc->rtp_header_extensions()[i].uri;
+    os << kSdpDelimiterColon << extension.id;
+    if (extension.encrypted) {
+      os << kSdpDelimiterSpace << RtpExtension::kEncryptHeaderExtensionsUri;
+    }
+    os << kSdpDelimiterSpace << extension.uri;
     AddLine(os.str(), message);
   }
 
   // RFC 3264
   // a=sendrecv || a=sendonly || a=sendrecv || a=inactive
   switch (media_desc->direction()) {
     case cricket::MD_INACTIVE:
       InitAttrLine(kAttributeInactive, &os);
       break;
     case cricket::MD_SENDONLY:
@@ skipping 1764 matching lines @@
     UpdateCodec<AudioContentDescription, cricket::AudioCodec>(
         media_desc, payload_type, feedback_param);
   } else if (media_type == cricket::MEDIA_TYPE_VIDEO) {
     UpdateCodec<VideoContentDescription, cricket::VideoCodec>(
         media_desc, payload_type, feedback_param);
   }
   return true;
 }
 
 }  // namespace webrtc