Handle case where UDP packet contains multiple DTLS records.

webrtc/p2p/base/dtlstransportchannel_unittest.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 652 matching lines @@
 
 // Create two channels with DTLS, and transfer some data.
 TEST_F(DtlsTransportChannelTest, TestTransferDtlsTwoChannels) {
   SetChannelCount(2);
   PrepareDtls(true, true, rtc::KT_DEFAULT);
   ASSERT_TRUE(Connect());
   TestTransfer(0, 1000, 100, false);
   TestTransfer(1, 1000, 100, false);
 }
 
+// Connect with DTLS, combine multiple DTLS records into one packet.

[Taylor Brandstetter, 2017/07/06 22:06:11]

May be nice to have some context here; "Our DTLS implementation doesn't do this,
but other implementations may; see
https://tools.ietf.org/html/rfc6347#section-4.1.1."

Also, do you know what other implementations are known for doing this? Are they
not using OpenSSL/BoringSSL? Or are they using some option we don't know about?

[joachim, 2017/07/07 16:12:59]

Done
According to https://crbug.com/537189 this seems to be an interop problem with
ORTCLib (I mention this in the comment now). On their website
(http://ortclib.org/) they write about using OpenSSL for security, but I don't
know any details about their actual DTLS implementation.

+TEST_F(DtlsTransportChannelTest, TestTransferDtlsCombineRecords) {
+  PrepareDtls(true, true, rtc::KT_DEFAULT);
+  ASSERT_TRUE(Connect());
+  cricket::FakeIceTransport* transport = client1_.GetFakeIceTransort(0);
+  transport->set_combine(true);

[Taylor Brandstetter, 2017/07/06 22:06:11]

Would be nice to have a comment saying something like: "Our DTLS implementation
always sends one record per packet, so to simulate an endpoint that sends
multiple records per packet, we configure the fake ICE transport to combine
every two consecutive packets into a single packet."

[joachim, 2017/07/07 16:12:59]

Done.

+  TestTransfer(0, 500, 100, false);
+}
+
 // Connect with A doing DTLS and B not, and transfer some data.
 TEST_F(DtlsTransportChannelTest, TestTransferDtlsRejected) {
   PrepareDtls(true, false, rtc::KT_DEFAULT);
   ASSERT_TRUE(Connect());
   TestTransfer(0, 1000, 100, false);
 }
 
 // Connect with B doing DTLS and A not, and transfer some data.
 TEST_F(DtlsTransportChannelTest, TestTransferDtlsNotOffered) {
   PrepareDtls(false, true, rtc::KT_DEFAULT);
@@ skipping 426 matching lines @@
             std::vector<DtlsTransportEvent>{
                 CALLER_RECEIVES_CLIENTHELLO, CALLER_RECEIVES_FINGERPRINT,
                 CALLER_WRITABLE, HANDSHAKE_FINISHES},
             std::vector<DtlsTransportEvent>{
                 CALLER_RECEIVES_CLIENTHELLO, CALLER_WRITABLE,
                 CALLER_RECEIVES_FINGERPRINT, HANDSHAKE_FINISHES},
             std::vector<DtlsTransportEvent>{CALLER_RECEIVES_CLIENTHELLO,
                                             CALLER_WRITABLE, HANDSHAKE_FINISHES,
                                             CALLER_RECEIVES_FINGERPRINT}),
         ::testing::Bool()));