Parse the connection data in SDP (c= line).

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 1882 matching lines @@
 bool IsRtp(const std::string& protocol) {
   return protocol.empty() ||
       (protocol.find(cricket::kMediaProtocolRtpPrefix) != std::string::npos);
 }
 
 bool IsDtlsSctp(const std::string& protocol) {
   // This intentionally excludes "SCTP" and "SCTP/DTLS".
   return protocol.find(cricket::kMediaProtocolDtlsSctp) != std::string::npos;
 }
 
+bool ParseConnectionData(const std::string line, rtc::SocketAddress* addr) {

[Taylor Brandstetter, 2017/03/10 22:41:18]

Meant to be const ref string?

[Zhi Huang, 2017/03/15 04:04:59]

Ah, yes. I missed the &.

+  // Parse the line from left to right.
+  std::string token;
+  std::string rightpart;
+  // RFC 4566
+  // c=<nettype> <addrtype> <connection-address>
+  // Skip "c=<nettype>".

[Taylor Brandstetter, 2017/03/10 22:41:18]

We should verify that "nettype" is "IN" since that's all we support.

[Zhi Huang, 2017/03/15 04:04:59]

Done.

+  if (!rtc::tokenize_first(line, kSdpDelimiterSpace, &token, &rightpart)) {
+    return false;
+  }
+  // Skip the "<addrtype>".

[Taylor Brandstetter, 2017/03/10 22:41:18]

To be more thorough, we could verify that addrtype matches the type of the
parsed address (IP4 or IP6), if the address is a literal IP address and not a
domain name.

[Zhi Huang, 2017/03/15 04:04:59]

Done.

+  if (!rtc::tokenize_first(rightpart, kSdpDelimiterSpace, &token, &rightpart)) {
+    return false;
+  }
+  // Extract the IP address. The rightpart part should be the IP address without
+  // the slash which is used for multicast.
+  if (rightpart.find('/') != std::string::npos) {
+    LOG(LS_ERROR) << "Failed to parse the connection data. Multicast is not "

[Taylor Brandstetter, 2017/03/10 22:41:18]

This method should take an error output parameter and do:

return ParseFailed(
    line,
    "Failed to parse the connection data. Multicast is not currently
supported.",
    error);

In order to return errors.

[Zhi Huang, 2017/03/15 04:04:59]

Done.

+                     "currently supported.";
+    return false;
+  }
+  addr->SetIP(rightpart);
+  return true;
+}
+
 bool ParseSessionDescription(const std::string& message, size_t* pos,
                              std::string* session_id,
                              std::string* session_version,
                              TransportDescription* session_td,
                              RtpHeaderExtensions* session_extmaps,
                              cricket::SessionDescription* desc,
                              SdpParseError* error) {
   std::string line;
 
   desc->set_msid_supported(false);
@@ skipping 42 matching lines @@
   // e=* (email address)
   GetLineWithType(message, pos, &line, kLineTypeSessionEmail);
 
   // RFC 4566
   // p=* (phone number)
   GetLineWithType(message, pos, &line, kLineTypeSessionPhone);
 
   // RFC 4566
   // c=* (connection information -- not required if included in
   //      all media)
-  GetLineWithType(message, pos, &line, kLineTypeConnection);
+  if (GetLineWithType(message, pos, &line, kLineTypeConnection)) {
+    rtc::SocketAddress addr;
+    if (!ParseConnectionData(line, &addr)) {
+      LOG(LS_ERROR) << "Failed to parse the session level connection data:"

[Taylor Brandstetter, 2017/03/10 22:41:18]

This doesn't need to log an error if ParseConnectionData already did.

[Zhi Huang, 2017/03/15 04:04:59]

Done.

+                    << line;
+      return false;
+    }
+    desc->set_session_connection_addr(rtc::Optional<rtc::SocketAddress>(addr));
+  }
 
   // RFC 4566
   // b=* (zero or more bandwidth information lines)
   while (GetLineWithType(message, pos, &line, kLineTypeSessionBandwidth)) {
     // By pass zero or more b lines.
   }
 
   // RFC 4566
   // One or more time descriptions ("t=" and "r=" lines; see below)
   // t=  (time the session is active)
@@ skipping 283 matching lines @@
       *content_name = cricket::CN_DATA;
       break;
     default:
       RTC_NOTREACHED();
       break;
   }
   if (!ParseContent(message, media_type, mline_index, protocol, payload_types,
                     pos, content_name, bundle_only, media_desc, transport,
                     candidates, error)) {
     delete media_desc;
-    return NULL;
+    return nullptr;
   }
   // Sort the codecs according to the m-line fmt list.
   std::unordered_map<int, int> payload_type_preferences;
   // "size + 1" so that the lowest preference payload type has a preference of
   // 1, which is greater than the default (0) for payload types not in the fmt
   // list.
   int preference = static_cast<int>(payload_types.size() + 1);
   for (int pt : payload_types) {
     payload_type_preferences[pt] = preference--;
   }
@@ skipping 381 matching lines @@
             return ParseFailed(line, description.str(), error);
           }
           // Prevent integer overflow.
           b = std::min(b, INT_MAX / 1000);
           media_desc->set_bandwidth(b * 1000);
         }
       }
       continue;
     }
 
+    // Parse the media level connection data.
+    if (IsLineType(line, kLineTypeConnection)) {
+      rtc::SocketAddress addr;
+      if (!ParseConnectionData(line, &addr)) {
+        LOG(LS_ERROR) << "Failed to parse the session level connection data:"
+                      << line;
+        return false;
+      }
+      media_desc->set_media_connection_addr(
+          rtc::Optional<rtc::SocketAddress>(addr));
+      continue;
+    }
+
     if (!IsLineType(line, kLineTypeAttributes)) {
       // TODO: Handle other lines if needed.
       LOG(LS_INFO) << "Ignored line: " << line;
       continue;
     }
 
     // Handle attributes common to SCTP and RTP.
     if (HasAttribute(line, kAttributeMid)) {
       // RFC 3388
       // mid-attribute      = "a=mid:" identification-tag
@@ skipping 553 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