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      1 /*
      2  * libjingle
      3  * Copyright 2013 Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include <errno.h>
     29 #include <stdarg.h>
     30 #include <stdio.h>
     31 #include <string>
     32 #include <vector>
     33 
     34 #include "talk/media/base/constants.h"
     35 #include "talk/media/base/mediachannel.h"
     36 #include "talk/media/sctp/sctpdataengine.h"
     37 #include "webrtc/base/bind.h"
     38 #include "webrtc/base/buffer.h"
     39 #include "webrtc/base/criticalsection.h"
     40 #include "webrtc/base/gunit.h"
     41 #include "webrtc/base/helpers.h"
     42 #include "webrtc/base/messagehandler.h"
     43 #include "webrtc/base/messagequeue.h"
     44 #include "webrtc/base/scoped_ptr.h"
     45 #include "webrtc/base/ssladapter.h"
     46 #include "webrtc/base/thread.h"
     47 
     48 enum {
     49   MSG_PACKET = 1,
     50 };
     51 
     52 // Fake NetworkInterface that sends/receives sctp packets.  The one in
     53 // talk/media/base/fakenetworkinterface.h only works with rtp/rtcp.
     54 class SctpFakeNetworkInterface : public cricket::MediaChannel::NetworkInterface,
     55                                  public rtc::MessageHandler {
     56  public:
     57   explicit SctpFakeNetworkInterface(rtc::Thread* thread)
     58     : thread_(thread),
     59       dest_(NULL) {
     60   }
     61 
     62   void SetDestination(cricket::DataMediaChannel* dest) { dest_ = dest; }
     63 
     64  protected:
     65   // Called to send raw packet down the wire (e.g. SCTP an packet).
     66   virtual bool SendPacket(rtc::Buffer* packet,
     67                           const rtc::PacketOptions& options) {
     68     LOG(LS_VERBOSE) << "SctpFakeNetworkInterface::SendPacket";
     69 
     70     // TODO(ldixon): Can/should we use Buffer.TransferTo here?
     71     // Note: this assignment does a deep copy of data from packet.
     72     rtc::Buffer* buffer = new rtc::Buffer(packet->data(), packet->size());
     73     thread_->Post(this, MSG_PACKET, rtc::WrapMessageData(buffer));
     74     LOG(LS_VERBOSE) << "SctpFakeNetworkInterface::SendPacket, Posted message.";
     75     return true;
     76   }
     77 
     78   // Called when a raw packet has been recieved. This passes the data to the
     79   // code that will interpret the packet. e.g. to get the content payload from
     80   // an SCTP packet.
     81   virtual void OnMessage(rtc::Message* msg) {
     82     LOG(LS_VERBOSE) << "SctpFakeNetworkInterface::OnMessage";
     83     rtc::scoped_ptr<rtc::Buffer> buffer(
     84         static_cast<rtc::TypedMessageData<rtc::Buffer*>*>(
     85             msg->pdata)->data());
     86     if (dest_) {
     87       dest_->OnPacketReceived(buffer.get(), rtc::PacketTime());
     88     }
     89     delete msg->pdata;
     90   }
     91 
     92   // Unsupported functions required to exist by NetworkInterface.
     93   // TODO(ldixon): Refactor parent NetworkInterface class so these are not
     94   // required. They are RTC specific and should be in an appropriate subclass.
     95   virtual bool SendRtcp(rtc::Buffer* packet,
     96                         const rtc::PacketOptions& options) {
     97     LOG(LS_WARNING) << "Unsupported: SctpFakeNetworkInterface::SendRtcp.";
     98     return false;
     99   }
    100   virtual int SetOption(SocketType type, rtc::Socket::Option opt,
    101                         int option) {
    102     LOG(LS_WARNING) << "Unsupported: SctpFakeNetworkInterface::SetOption.";
    103     return 0;
    104   }
    105   virtual void SetDefaultDSCPCode(rtc::DiffServCodePoint dscp) {
    106     LOG(LS_WARNING) << "Unsupported: SctpFakeNetworkInterface::SetOption.";
    107   }
    108 
    109  private:
    110   // Not owned by this class.
    111   rtc::Thread* thread_;
    112   cricket::DataMediaChannel* dest_;
    113 };
    114 
    115 // This is essentially a buffer to hold recieved data. It stores only the last
    116 // received data. Calling OnDataReceived twice overwrites old data with the
    117 // newer one.
    118 // TODO(ldixon): Implement constraints, and allow new data to be added to old
    119 // instead of replacing it.
    120 class SctpFakeDataReceiver : public sigslot::has_slots<> {
    121  public:
    122   SctpFakeDataReceiver() : received_(false) {}
    123 
    124   void Clear() {
    125     received_ = false;
    126     last_data_ = "";
    127     last_params_ = cricket::ReceiveDataParams();
    128   }
    129 
    130   virtual void OnDataReceived(const cricket::ReceiveDataParams& params,
    131                               const char* data, size_t length) {
    132     received_ = true;
    133     last_data_ = std::string(data, length);
    134     last_params_ = params;
    135   }
    136 
    137   bool received() const { return received_; }
    138   std::string last_data() const { return last_data_; }
    139   cricket::ReceiveDataParams last_params() const { return last_params_; }
    140 
    141  private:
    142   bool received_;
    143   std::string last_data_;
    144   cricket::ReceiveDataParams last_params_;
    145 };
    146 
    147 class SignalReadyToSendObserver : public sigslot::has_slots<> {
    148  public:
    149   SignalReadyToSendObserver() : signaled_(false), writable_(false) {}
    150 
    151   void OnSignaled(bool writable) {
    152     signaled_ = true;
    153     writable_ = writable;
    154   }
    155 
    156   bool IsSignaled(bool writable) {
    157     return signaled_ && (writable_ == writable);
    158   }
    159 
    160  private:
    161   bool signaled_;
    162   bool writable_;
    163 };
    164 
    165 class SignalChannelClosedObserver : public sigslot::has_slots<> {
    166  public:
    167   SignalChannelClosedObserver() {}
    168   void BindSelf(cricket::SctpDataMediaChannel* channel) {
    169     channel->SignalStreamClosedRemotely.connect(
    170         this, &SignalChannelClosedObserver::OnStreamClosed);
    171   }
    172   void OnStreamClosed(uint32_t stream) { streams_.push_back(stream); }
    173 
    174   int StreamCloseCount(uint32_t stream) {
    175     return std::count(streams_.begin(), streams_.end(), stream);
    176   }
    177 
    178   bool WasStreamClosed(uint32_t stream) {
    179     return std::find(streams_.begin(), streams_.end(), stream)
    180         != streams_.end();
    181   }
    182 
    183  private:
    184   std::vector<uint32_t> streams_;
    185 };
    186 
    187 class SignalChannelClosedReopener : public sigslot::has_slots<> {
    188  public:
    189   SignalChannelClosedReopener(cricket::SctpDataMediaChannel* channel,
    190                               cricket::SctpDataMediaChannel* peer)
    191       : channel_(channel), peer_(peer) {}
    192 
    193   void OnStreamClosed(int stream) {
    194     cricket::StreamParams p(cricket::StreamParams::CreateLegacy(stream));
    195     channel_->AddSendStream(p);
    196     channel_->AddRecvStream(p);
    197     peer_->AddSendStream(p);
    198     peer_->AddRecvStream(p);
    199     streams_.push_back(stream);
    200   }
    201 
    202   int StreamCloseCount(int stream) {
    203     return std::count(streams_.begin(), streams_.end(), stream);
    204   }
    205 
    206  private:
    207   cricket::SctpDataMediaChannel* channel_;
    208   cricket::SctpDataMediaChannel* peer_;
    209   std::vector<int> streams_;
    210 };
    211 
    212 // SCTP Data Engine testing framework.
    213 class SctpDataMediaChannelTest : public testing::Test,
    214                                  public sigslot::has_slots<> {
    215  protected:
    216   // usrsctp uses the NSS random number generator on non-Android platforms,
    217   // so we need to initialize SSL.
    218   static void SetUpTestCase() {
    219   }
    220 
    221   virtual void SetUp() {
    222     engine_.reset(new cricket::SctpDataEngine());
    223   }
    224 
    225   void SetupConnectedChannels() {
    226     net1_.reset(new SctpFakeNetworkInterface(rtc::Thread::Current()));
    227     net2_.reset(new SctpFakeNetworkInterface(rtc::Thread::Current()));
    228     recv1_.reset(new SctpFakeDataReceiver());
    229     recv2_.reset(new SctpFakeDataReceiver());
    230     chan1_ready_to_send_count_ = 0;
    231     chan2_ready_to_send_count_ = 0;
    232     chan1_.reset(CreateChannel(net1_.get(), recv1_.get()));
    233     chan1_->set_debug_name("chan1/connector");
    234     chan1_->SignalReadyToSend.connect(
    235         this, &SctpDataMediaChannelTest::OnChan1ReadyToSend);
    236     chan2_.reset(CreateChannel(net2_.get(), recv2_.get()));
    237     chan2_->set_debug_name("chan2/listener");
    238     chan2_->SignalReadyToSend.connect(
    239         this, &SctpDataMediaChannelTest::OnChan2ReadyToSend);
    240     // Setup two connected channels ready to send and receive.
    241     net1_->SetDestination(chan2_.get());
    242     net2_->SetDestination(chan1_.get());
    243 
    244     LOG(LS_VERBOSE) << "Channel setup ----------------------------- ";
    245     AddStream(1);
    246     AddStream(2);
    247 
    248     LOG(LS_VERBOSE) << "Connect the channels -----------------------------";
    249     // chan1 wants to setup a data connection.
    250     chan1_->SetReceive(true);
    251     // chan1 will have sent chan2 a request to setup a data connection. After
    252     // chan2 accepts the offer, chan2 connects to chan1 with the following.
    253     chan2_->SetReceive(true);
    254     chan2_->SetSend(true);
    255     // Makes sure that network packets are delivered and simulates a
    256     // deterministic and realistic small timing delay between the SetSend calls.
    257     ProcessMessagesUntilIdle();
    258 
    259     // chan1 and chan2 are now connected so chan1 enables sending to complete
    260     // the creation of the connection.
    261     chan1_->SetSend(true);
    262   }
    263 
    264   virtual void TearDown() {
    265     channel1()->SetSend(false);
    266     channel2()->SetSend(false);
    267 
    268     // Process messages until idle to prevent a sent packet from being dropped
    269     // and causing memory leaks (not being deleted by the receiver).
    270     ProcessMessagesUntilIdle();
    271   }
    272 
    273   bool AddStream(int ssrc) {
    274     bool ret = true;
    275     cricket::StreamParams p(cricket::StreamParams::CreateLegacy(ssrc));
    276     ret = ret && chan1_->AddSendStream(p);
    277     ret = ret && chan1_->AddRecvStream(p);
    278     ret = ret && chan2_->AddSendStream(p);
    279     ret = ret && chan2_->AddRecvStream(p);
    280     return ret;
    281   }
    282 
    283   cricket::SctpDataMediaChannel* CreateChannel(
    284       SctpFakeNetworkInterface* net, SctpFakeDataReceiver* recv) {
    285     cricket::SctpDataMediaChannel* channel =
    286         static_cast<cricket::SctpDataMediaChannel*>(engine_->CreateChannel(
    287             cricket::DCT_SCTP));
    288     channel->SetInterface(net);
    289     // When data is received, pass it to the SctpFakeDataReceiver.
    290     channel->SignalDataReceived.connect(
    291         recv, &SctpFakeDataReceiver::OnDataReceived);
    292     return channel;
    293   }
    294 
    295   bool SendData(cricket::SctpDataMediaChannel* chan,
    296                 uint32_t ssrc,
    297                 const std::string& msg,
    298                 cricket::SendDataResult* result) {
    299     cricket::SendDataParams params;
    300     params.ssrc = ssrc;
    301 
    302     return chan->SendData(params, rtc::Buffer(
    303         &msg[0], msg.length()), result);
    304   }
    305 
    306   bool ReceivedData(const SctpFakeDataReceiver* recv,
    307                     uint32_t ssrc,
    308                     const std::string& msg) {
    309     return (recv->received() &&
    310             recv->last_params().ssrc == ssrc &&
    311             recv->last_data() == msg);
    312   }
    313 
    314   bool ProcessMessagesUntilIdle() {
    315     rtc::Thread* thread = rtc::Thread::Current();
    316     while (!thread->empty()) {
    317       rtc::Message msg;
    318       if (thread->Get(&msg, rtc::Thread::kForever)) {
    319         thread->Dispatch(&msg);
    320       }
    321     }
    322     return !thread->IsQuitting();
    323   }
    324 
    325   cricket::SctpDataMediaChannel* channel1() { return chan1_.get(); }
    326   cricket::SctpDataMediaChannel* channel2() { return chan2_.get(); }
    327   SctpFakeDataReceiver* receiver1() { return recv1_.get(); }
    328   SctpFakeDataReceiver* receiver2() { return recv2_.get(); }
    329 
    330   int channel1_ready_to_send_count() { return chan1_ready_to_send_count_; }
    331   int channel2_ready_to_send_count() { return chan2_ready_to_send_count_; }
    332  private:
    333   rtc::scoped_ptr<cricket::SctpDataEngine> engine_;
    334   rtc::scoped_ptr<SctpFakeNetworkInterface> net1_;
    335   rtc::scoped_ptr<SctpFakeNetworkInterface> net2_;
    336   rtc::scoped_ptr<SctpFakeDataReceiver> recv1_;
    337   rtc::scoped_ptr<SctpFakeDataReceiver> recv2_;
    338   rtc::scoped_ptr<cricket::SctpDataMediaChannel> chan1_;
    339   rtc::scoped_ptr<cricket::SctpDataMediaChannel> chan2_;
    340 
    341   int chan1_ready_to_send_count_;
    342   int chan2_ready_to_send_count_;
    343 
    344   void OnChan1ReadyToSend(bool send) {
    345     if (send)
    346       ++chan1_ready_to_send_count_;
    347   }
    348   void OnChan2ReadyToSend(bool send) {
    349     if (send)
    350       ++chan2_ready_to_send_count_;
    351   }
    352 };
    353 
    354 // Verifies that SignalReadyToSend is fired.
    355 TEST_F(SctpDataMediaChannelTest, SignalReadyToSend) {
    356   SetupConnectedChannels();
    357 
    358   SignalReadyToSendObserver signal_observer_1;
    359   SignalReadyToSendObserver signal_observer_2;
    360 
    361   channel1()->SignalReadyToSend.connect(&signal_observer_1,
    362                                         &SignalReadyToSendObserver::OnSignaled);
    363   channel2()->SignalReadyToSend.connect(&signal_observer_2,
    364                                         &SignalReadyToSendObserver::OnSignaled);
    365 
    366   cricket::SendDataResult result;
    367   ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
    368   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    369   EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
    370   ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
    371   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    372   EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);
    373 
    374   EXPECT_TRUE_WAIT(signal_observer_1.IsSignaled(true), 1000);
    375   EXPECT_TRUE_WAIT(signal_observer_2.IsSignaled(true), 1000);
    376 }
    377 
    378 TEST_F(SctpDataMediaChannelTest, SendData) {
    379   SetupConnectedChannels();
    380 
    381   cricket::SendDataResult result;
    382   LOG(LS_VERBOSE) << "chan1 sending: 'hello?' -----------------------------";
    383   ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
    384   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    385   EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
    386   LOG(LS_VERBOSE) << "recv2.received=" << receiver2()->received()
    387                   << ", recv2.last_params.ssrc="
    388                   << receiver2()->last_params().ssrc
    389                   << ", recv2.last_params.timestamp="
    390                   << receiver2()->last_params().ssrc
    391                   << ", recv2.last_params.seq_num="
    392                   << receiver2()->last_params().seq_num
    393                   << ", recv2.last_data=" << receiver2()->last_data();
    394 
    395   LOG(LS_VERBOSE) << "chan2 sending: 'hi chan1' -----------------------------";
    396   ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
    397   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    398   EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);
    399   LOG(LS_VERBOSE) << "recv1.received=" << receiver1()->received()
    400                   << ", recv1.last_params.ssrc="
    401                   << receiver1()->last_params().ssrc
    402                   << ", recv1.last_params.timestamp="
    403                   << receiver1()->last_params().ssrc
    404                   << ", recv1.last_params.seq_num="
    405                   << receiver1()->last_params().seq_num
    406                   << ", recv1.last_data=" << receiver1()->last_data();
    407 }
    408 
    409 // Sends a lot of large messages at once and verifies SDR_BLOCK is returned.
    410 TEST_F(SctpDataMediaChannelTest, SendDataBlocked) {
    411   SetupConnectedChannels();
    412 
    413   cricket::SendDataResult result;
    414   cricket::SendDataParams params;
    415   params.ssrc = 1;
    416 
    417   std::vector<char> buffer(1024 * 64, 0);
    418 
    419   for (size_t i = 0; i < 100; ++i) {
    420     channel1()->SendData(
    421         params, rtc::Buffer(&buffer[0], buffer.size()), &result);
    422     if (result == cricket::SDR_BLOCK)
    423       break;
    424   }
    425 
    426   EXPECT_EQ(cricket::SDR_BLOCK, result);
    427 }
    428 
    429 TEST_F(SctpDataMediaChannelTest, ClosesRemoteStream) {
    430   SetupConnectedChannels();
    431   SignalChannelClosedObserver chan_1_sig_receiver, chan_2_sig_receiver;
    432   chan_1_sig_receiver.BindSelf(channel1());
    433   chan_2_sig_receiver.BindSelf(channel2());
    434 
    435   cricket::SendDataResult result;
    436   ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
    437   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    438   EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
    439   ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
    440   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    441   EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);
    442 
    443   // Close channel 1.  Channel 2 should notify us.
    444   channel1()->RemoveSendStream(1);
    445   EXPECT_TRUE_WAIT(chan_2_sig_receiver.WasStreamClosed(1), 1000);
    446 }
    447 
    448 TEST_F(SctpDataMediaChannelTest, ClosesTwoRemoteStreams) {
    449   SetupConnectedChannels();
    450   AddStream(3);
    451   SignalChannelClosedObserver chan_1_sig_receiver, chan_2_sig_receiver;
    452   chan_1_sig_receiver.BindSelf(channel1());
    453   chan_2_sig_receiver.BindSelf(channel2());
    454 
    455   cricket::SendDataResult result;
    456   ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
    457   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    458   EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
    459   ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
    460   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    461   EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);
    462 
    463   // Close two streams on one side.
    464   channel2()->RemoveSendStream(2);
    465   channel2()->RemoveSendStream(3);
    466   EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(2), 1000);
    467   EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(3), 1000);
    468 }
    469 
    470 TEST_F(SctpDataMediaChannelTest, ClosesStreamsOnBothSides) {
    471   SetupConnectedChannels();
    472   AddStream(3);
    473   AddStream(4);
    474   SignalChannelClosedObserver chan_1_sig_receiver, chan_2_sig_receiver;
    475   chan_1_sig_receiver.BindSelf(channel1());
    476   chan_2_sig_receiver.BindSelf(channel2());
    477 
    478   cricket::SendDataResult result;
    479   ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
    480   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    481   EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
    482   ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
    483   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    484   EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);
    485 
    486   // Close one stream on channel1(), while closing three streams on
    487   // channel2().  They will conflict (only one side can close anything at a
    488   // time, apparently).  Test the resolution of the conflict.
    489   channel1()->RemoveSendStream(1);
    490 
    491   channel2()->RemoveSendStream(2);
    492   channel2()->RemoveSendStream(3);
    493   channel2()->RemoveSendStream(4);
    494   EXPECT_TRUE_WAIT(chan_2_sig_receiver.WasStreamClosed(1), 1000);
    495   EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(2), 1000);
    496   EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(3), 1000);
    497   EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(4), 1000);
    498 }
    499 
    500 TEST_F(SctpDataMediaChannelTest, EngineSignalsRightChannel) {
    501   SetupConnectedChannels();
    502   EXPECT_TRUE_WAIT(channel1()->socket() != NULL, 1000);
    503   struct socket *sock = const_cast<struct socket*>(channel1()->socket());
    504   int prior_count = channel1_ready_to_send_count();
    505   cricket::SctpDataEngine::SendThresholdCallback(sock, 0);
    506   EXPECT_GT(channel1_ready_to_send_count(), prior_count);
    507 }
    508 
    509 TEST_F(SctpDataMediaChannelTest, RefusesHighNumberedChannels) {
    510   SetupConnectedChannels();
    511   EXPECT_TRUE(AddStream(1022));
    512   EXPECT_FALSE(AddStream(1023));
    513 }
    514 
    515 // Flaky on Linux and Windows. See webrtc:4453.
    516 #if defined(WEBRTC_WIN) || defined(WEBRTC_LINUX)
    517 #define MAYBE_ReusesAStream DISABLED_ReusesAStream
    518 #else
    519 #define MAYBE_ReusesAStream ReusesAStream
    520 #endif
    521 TEST_F(SctpDataMediaChannelTest, MAYBE_ReusesAStream) {
    522   // Shut down channel 1, then open it up again for reuse.
    523   SetupConnectedChannels();
    524   cricket::SendDataResult result;
    525   SignalChannelClosedObserver chan_2_sig_receiver;
    526   chan_2_sig_receiver.BindSelf(channel2());
    527 
    528   ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
    529   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    530   EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
    531 
    532   channel1()->RemoveSendStream(1);
    533   EXPECT_TRUE_WAIT(chan_2_sig_receiver.WasStreamClosed(1), 1000);
    534   // Channel 1 is gone now.
    535 
    536   // Create a new channel 1.
    537   AddStream(1);
    538   ASSERT_TRUE(SendData(channel1(), 1, "hi?", &result));
    539   EXPECT_EQ(cricket::SDR_SUCCESS, result);
    540   EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hi?"), 1000);
    541   channel1()->RemoveSendStream(1);
    542   EXPECT_TRUE_WAIT(chan_2_sig_receiver.StreamCloseCount(1) == 2, 1000);
    543 }
    544