From f15dee6980152cded2f10c26748d7d88ab9501ae Mon Sep 17 00:00:00 2001
From: "tommi@webrtc.org" <tommi@webrtc.org>
Date: Mon, 27 Oct 2014 22:15:04 +0000
Subject: [PATCH] Check if a datachannel in the current local description is an
 sctp channel before assuming rtp. When generating an offer from a local
 description when 'sctp' is not explicitly set in the media session options,
 we were generating an offer with an RTP datachannel even though the channel
 in the local description was already sctp.

R=pthatcher@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/28819004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7539 4adac7df-926f-26a2-2b94-8c16560cd09d
---
 talk/session/media/mediasession.cc          | 10 ++++++--
 talk/session/media/mediasession_unittest.cc | 27 +++++++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/talk/session/media/mediasession.cc b/talk/session/media/mediasession.cc
index 54eeffa600..79fc15144e 100644
--- a/talk/session/media/mediasession.cc
+++ b/talk/session/media/mediasession.cc
@@ -1191,8 +1191,14 @@ SessionDescription* MediaSessionDescriptionFactory::CreateOffer(
         }
         video_added = true;
       } else if (IsMediaContentOfType(&*it, MEDIA_TYPE_DATA)) {
-        if (!AddDataContentForOffer(options, current_description, &data_codecs,
-                                    &current_streams, offer.get())) {
+        MediaSessionOptions options_copy(options);
+        if (IsSctp(static_cast<const MediaContentDescription*>(
+                it->description))) {
+          options_copy.data_channel_type = DCT_SCTP;
+        }
+        if (!AddDataContentForOffer(options_copy, current_description,
+                                    &data_codecs, &current_streams,
+                                    offer.get())) {
           return NULL;
         }
         data_added = true;
diff --git a/talk/session/media/mediasession_unittest.cc b/talk/session/media/mediasession_unittest.cc
index ef155f0878..e3c678ee12 100644
--- a/talk/session/media/mediasession_unittest.cc
+++ b/talk/session/media/mediasession_unittest.cc
@@ -628,6 +628,33 @@ TEST_F(MediaSessionDescriptionFactoryTest, TestCreateSctpDataOffer) {
   EXPECT_TRUE(offer->GetContentByName("data") != NULL);
 }
 
+// Test creating an sctp data channel from an already generated offer.
+TEST_F(MediaSessionDescriptionFactoryTest, TestCreateImplicitSctpDataOffer) {
+  MediaSessionOptions opts;
+  opts.recv_audio = false;
+  opts.bundle_enabled = true;
+  opts.data_channel_type = cricket::DCT_SCTP;
+  f1_.set_secure(SEC_ENABLED);
+  rtc::scoped_ptr<SessionDescription> offer1(f1_.CreateOffer(opts, NULL));
+  ASSERT_TRUE(offer1.get() != NULL);
+  const ContentInfo* data = offer1->GetContentByName("data");
+  ASSERT_TRUE(data != NULL);
+  const MediaContentDescription* mdesc =
+      static_cast<const MediaContentDescription*>(data->description);
+  ASSERT_EQ(cricket::kMediaProtocolSctp, mdesc->protocol());
+
+  // Now set data_channel_type to 'none' (default) and make sure that the
+  // datachannel type that gets generated from the previous offer, is of the
+  // same type.
+  opts.data_channel_type = cricket::DCT_NONE;
+  rtc::scoped_ptr<SessionDescription> offer2(
+      f1_.CreateOffer(opts, offer1.get()));
+  data = offer2->GetContentByName("data");
+  ASSERT_TRUE(data != NULL);
+  mdesc = static_cast<const MediaContentDescription*>(data->description);
+  EXPECT_EQ(cricket::kMediaProtocolSctp, mdesc->protocol());
+}
+
 // Create an audio, video offer without legacy StreamParams.
 TEST_F(MediaSessionDescriptionFactoryTest,
        TestCreateOfferWithoutLegacyStreams) {