Quelle  channel_unittest.cc   Sprache: C

/*
 *  Copyright 2009 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.
 */

#include "pc/channel.h"

#include <stddef.h>

#include <cstdint>
#include <string>
#include <type_traits>

#include "absl/functional/any_invocable.h"
#include "api/array_view.h"
#include "api/audio_options.h"
#include "api/rtp_parameters.h"
#include "api/task_queue/pending_task_safety_flag.h"
#include "media/base/codec.h"
#include "media/base/fake_media_engine.h"
#include "media/base/fake_rtp.h"
#include "media/base/media_channel.h"
#include "media/base/media_constants.h"
#include "media/base/rid_description.h"
#include "p2p/base/candidate_pair_interface.h"
#include "p2p/base/dtls_transport_internal.h"
#include "p2p/base/fake_dtls_transport.h"
#include "p2p/base/fake_packet_transport.h"
#include "p2p/base/ice_transport_internal.h"
#include "p2p/base/p2p_constants.h"
#include "p2p/base/packet_transport_internal.h"
#include "pc/dtls_srtp_transport.h"
#include "pc/jsep_transport.h"
#include "pc/rtp_transport.h"
#include "rtc_base/arraysize.h"
#include "rtc_base/buffer.h"
#include "rtc_base/byte_order.h"
#include "rtc_base/checks.h"
#include "rtc_base/rtc_certificate.h"
#include "rtc_base/ssl_identity.h"
#include "rtc_base/task_queue_for_test.h"
#include "test/gmock.h"
#include "test/gtest.h"
#include "test/scoped_key_value_config.h"

namespace {

using ::cricket::DtlsTransportInternal;
using ::cricket::FakeVoiceMediaReceiveChannel;
using ::cricket::FakeVoiceMediaSendChannel;
using ::cricket::RidDescription;
using ::cricket::RidDirection;
using ::cricket::StreamParams;
using ::testing::AllOf;
using ::testing::ElementsAre;
using ::testing::Field;
using ::webrtc::RtpTransceiverDirection;
using ::webrtc::SdpType;

const cricket::Codec kPcmuCodec =
    cricket::CreateAudioCodec(0, "PCMU", 64000, 1);
const cricket::Codec kPcmaCodec =
    cricket::CreateAudioCodec(8, "PCMA", 64000, 1);
const cricket::Codec kIsacCodec =
    cricket::CreateAudioCodec(103, "ISAC", 40000, 1);
const cricket::Codec kH264Codec = cricket::CreateVideoCodec(97, "H264");
const cricket::Codec kH264SvcCodec = cricket::CreateVideoCodec(99, "H264-SVC");
const uint32_t kSsrc1 = 0x1111;
const uint32_t kSsrc2 = 0x2222;
const uint32_t kSsrc3 = 0x3333;
const uint32_t kSsrc4 = 0x4444;
const int kAudioPts[] = {0, 8};
const int kVideoPts[] = {97, 99};
enum class NetworkIsWorker { Yes, No };


template <class ChannelT,
          class MediaSendChannelT,
          class MediaReceiveChannelT,
          class MediaSendChannelInterfaceT,
          class MediaReceiveChannelInterfaceT,
          class ContentT,
          class MediaInfoT,
          class OptionsT>
class Traits {
 public:
  typedef ChannelT Channel;
  typedef MediaSendChannelT MediaSendChannel;
  typedef MediaReceiveChannelT MediaReceiveChannel;
  typedef MediaSendChannelInterfaceT MediaSendChannelInterface;
  typedef MediaReceiveChannelInterfaceT MediaReceiveChannelInterface;
  typedef ContentT Content;
  typedef MediaInfoT MediaInfo;
  typedef OptionsT Options;
};

class VoiceTraits : public Traits<cricket::VoiceChannel,
                                  cricket::FakeVoiceMediaSendChannel,
                                  cricket::FakeVoiceMediaReceiveChannel,
                                  cricket::VoiceMediaSendChannelInterface,
                                  cricket::VoiceMediaReceiveChannelInterface,
                                  cricket::AudioContentDescription,
                                  cricket::VoiceMediaInfo,
                                  cricket::AudioOptions> {};

class VideoTraits : public Traits<cricket::VideoChannel,
                                  cricket::FakeVideoMediaSendChannel,
                                  cricket::FakeVideoMediaReceiveChannel,
                                  cricket::VideoMediaSendChannelInterface,
                                  cricket::VideoMediaReceiveChannelInterface,
                                  cricket::VideoContentDescription,
                                  cricket::VideoMediaInfo,
                                  cricket::VideoOptions> {};

// Base class for Voice/Video tests
template <class T>
class ChannelTest : public ::testing::Test, public sigslot::has_slots<> {
 public:
  enum Flags {
    RTCP_MUX = 0x1,
    SSRC_MUX = 0x8,
    DTLS = 0x10,
    // Use BaseChannel with PacketTransportInternal rather than
    // DtlsTransportInternal.
    RAW_PACKET_TRANSPORT = 0x20,
  };

  ChannelTest(bool verify_playout,
              rtc::ArrayView<const uint8_t> rtp_data,
              rtc::ArrayView<const uint8_t> rtcp_data,
              NetworkIsWorker network_is_worker)
      : verify_playout_(verify_playout),
        rtp_packet_(rtp_data.data(), rtp_data.size()),
        rtcp_packet_(rtcp_data.data(), rtcp_data.size()) {
    if (network_is_worker == NetworkIsWorker::Yes) {
      network_thread_ = rtc::Thread::Current();
    } else {
      network_thread_keeper_ = rtc::Thread::Create();
      network_thread_keeper_->SetName("Network", nullptr);
      network_thread_ = network_thread_keeper_.get();
    }
    RTC_DCHECK(network_thread_);
  }

  ~ChannelTest() {
    if (network_thread_) {
      SendTask(network_thread_, [this]() {
        network_thread_safety_->SetNotAlive();
        DeinitChannels();

        // Transports must be created and destroyed on the network thread.
        fake_rtp_dtls_transport1_ = nullptr;
        fake_rtcp_dtls_transport1_ = nullptr;
        fake_rtp_dtls_transport2_ = nullptr;
        fake_rtcp_dtls_transport2_ = nullptr;
        fake_rtp_packet_transport1_ = nullptr;
        fake_rtcp_packet_transport1_ = nullptr;
        fake_rtp_packet_transport2_ = nullptr;
        fake_rtcp_packet_transport2_ = nullptr;
        rtp_transport1_ = nullptr;
        rtp_transport2_ = nullptr;
        new_rtp_transport_ = nullptr;
      });
    }
  }

  void CreateChannels(int flags1, int flags2) {
    CreateChannels(std::make_unique<typename T::MediaSendChannel>(
                       typename T::Options(), network_thread_),
                   std::make_unique<typename T::MediaReceiveChannel>(
                       typename T::Options(), network_thread_),
                   std::make_unique<typename T::MediaSendChannel>(
                       typename T::Options(), network_thread_),
                   std::make_unique<typename T::MediaReceiveChannel>(
                       typename T::Options(), network_thread_),
                   flags1, flags2);
  }
  void CreateChannels(std::unique_ptr<typename T::MediaSendChannel> ch1s,
                      std::unique_ptr<typename T::MediaReceiveChannel> ch1r,
                      std::unique_ptr<typename T::MediaSendChannel> ch2s,
                      std::unique_ptr<typename T::MediaReceiveChannel> ch2r,
                      int flags1,
                      int flags2) {
    RTC_DCHECK(!channel1_);
    RTC_DCHECK(!channel2_);

    // Network thread is started in CreateChannels, to allow the test to
    // configure a fake clock before any threads are spawned and attempt to
    // access the time.
    if (network_thread_keeper_) {
      network_thread_keeper_->Start();
    }

    // Make sure if using raw packet transports, they're used for both
    // channels.
    RTC_DCHECK_EQ(flags1 & RAW_PACKET_TRANSPORT, flags2 & RAW_PACKET_TRANSPORT);
    rtc::Thread* worker_thread = rtc::Thread::Current();

    network_thread_->BlockingCall([&] {
      // Based on flags, create fake DTLS or raw packet transports.

      if (flags1 & RAW_PACKET_TRANSPORT) {
        fake_rtp_packet_transport1_.reset(
            new rtc::FakePacketTransport("channel1_rtp"));
        if (!(flags1 & RTCP_MUX)) {
          fake_rtcp_packet_transport1_.reset(
              new rtc::FakePacketTransport("channel1_rtcp"));
        }
      } else {
        // Confirmed to work with KT_RSA and KT_ECDSA.
        fake_rtp_dtls_transport1_.reset(new cricket::FakeDtlsTransport(
            "channel1", cricket::ICE_CANDIDATE_COMPONENT_RTP, network_thread_));
        if (!(flags1 & RTCP_MUX)) {
          fake_rtcp_dtls_transport1_.reset(new cricket::FakeDtlsTransport(
              "channel1", cricket::ICE_CANDIDATE_COMPONENT_RTCP,
              network_thread_));
        }
        if (flags1 & DTLS) {
          auto cert1 = rtc::RTCCertificate::Create(
              rtc::SSLIdentity::Create("session1", rtc::KT_DEFAULT));
          fake_rtp_dtls_transport1_->SetLocalCertificate(cert1);
          if (fake_rtcp_dtls_transport1_) {
            fake_rtcp_dtls_transport1_->SetLocalCertificate(cert1);
          }
        }
      }
      // Based on flags, create fake DTLS or raw packet transports.
      if (flags2 & RAW_PACKET_TRANSPORT) {
        fake_rtp_packet_transport2_.reset(
            new rtc::FakePacketTransport("channel2_rtp"));
        if (!(flags2 & RTCP_MUX)) {
          fake_rtcp_packet_transport2_.reset(
              new rtc::FakePacketTransport("channel2_rtcp"));
        }
      } else {
        // Confirmed to work with KT_RSA and KT_ECDSA.
        fake_rtp_dtls_transport2_.reset(new cricket::FakeDtlsTransport(
            "channel2", cricket::ICE_CANDIDATE_COMPONENT_RTP, network_thread_));
        if (!(flags2 & RTCP_MUX)) {
          fake_rtcp_dtls_transport2_.reset(new cricket::FakeDtlsTransport(
              "channel2", cricket::ICE_CANDIDATE_COMPONENT_RTCP,
              network_thread_));
        }
        if (flags2 & DTLS) {
          auto cert2 = rtc::RTCCertificate::Create(
              rtc::SSLIdentity::Create("session2", rtc::KT_DEFAULT));
          fake_rtp_dtls_transport2_->SetLocalCertificate(cert2);
          if (fake_rtcp_dtls_transport2_) {
            fake_rtcp_dtls_transport2_->SetLocalCertificate(cert2);
          }
        }
      }
      rtp_transport1_ = CreateRtpTransportBasedOnFlags(
          fake_rtp_packet_transport1_.get(), fake_rtcp_packet_transport1_.get(),
          fake_rtp_dtls_transport1_.get(), fake_rtcp_dtls_transport1_.get(),
          flags1);
      rtp_transport2_ = CreateRtpTransportBasedOnFlags(
          fake_rtp_packet_transport2_.get(), fake_rtcp_packet_transport2_.get(),
          fake_rtp_dtls_transport2_.get(), fake_rtcp_dtls_transport2_.get(),
          flags2);
    });

    channel1_ = CreateChannel(worker_thread, network_thread_, std::move(ch1s),
                              std::move(ch1r), rtp_transport1_.get(), flags1);
    channel2_ = CreateChannel(worker_thread, network_thread_, std::move(ch2s),
                              std::move(ch2r), rtp_transport2_.get(), flags2);
    CreateContent(flags1, kPcmuCodec, kH264Codec, &local_media_content1_);
    CreateContent(flags2, kPcmuCodec, kH264Codec, &local_media_content2_);
    CopyContent(local_media_content1_, &remote_media_content1_);
    CopyContent(local_media_content2_, &remote_media_content2_);

    // Add stream information (SSRC) to the local content but not to the remote
    // content. This means that we per default know the SSRC of what we send but
    // not what we receive.
    AddLegacyStreamInContent(kSsrc1, flags1, &local_media_content1_);
    AddLegacyStreamInContent(kSsrc2, flags2, &local_media_content2_);

    // If SSRC_MUX is used we also need to know the SSRC of the incoming stream.
    if (flags1 & SSRC_MUX) {
      AddLegacyStreamInContent(kSsrc1, flags1, &remote_media_content1_);
    }
    if (flags2 & SSRC_MUX) {
      AddLegacyStreamInContent(kSsrc2, flags2, &remote_media_content2_);
    }
  }
  std::unique_ptr<typename T::Channel> CreateChannel(
      rtc::Thread* worker_thread,
      rtc::Thread* network_thread,
      std::unique_ptr<typename T::MediaSendChannel> ch_send,
      std::unique_ptr<typename T::MediaReceiveChannel> ch_receive,
      webrtc::RtpTransportInternal* rtp_transport,
      int flags);

  std::unique_ptr<webrtc::RtpTransportInternal> CreateRtpTransportBasedOnFlags(
      rtc::PacketTransportInternal* rtp_packet_transport,
      rtc::PacketTransportInternal* rtcp_packet_transport,
      DtlsTransportInternal* rtp_dtls_transport,
      DtlsTransportInternal* rtcp_dtls_transport,
      int flags) {
    if (flags & RTCP_MUX) {
      rtcp_packet_transport = nullptr;
      rtcp_dtls_transport = nullptr;
    }

    if (flags & DTLS) {
      return CreateDtlsSrtpTransport(rtp_dtls_transport, rtcp_dtls_transport);
    } else {
      if (flags & RAW_PACKET_TRANSPORT) {
        return CreateUnencryptedTransport(rtp_packet_transport,
                                          rtcp_packet_transport);
      } else {
        return CreateUnencryptedTransport(rtp_dtls_transport,
                                          rtcp_dtls_transport);
      }
    }
  }

  // Unininitializes the channels on the network thread.
  void DeinitChannels() {
    if (!channel1_ && !channel2_)
      return;
    SendTask(network_thread_, [this]() {
      if (channel1_) {
        RTC_DCHECK_RUN_ON(channel1_->network_thread());
        channel1_->SetRtpTransport(nullptr);
      }
      if (channel2_) {
        RTC_DCHECK_RUN_ON(channel2_->network_thread());
        channel2_->SetRtpTransport(nullptr);
      }
    });
  }

  std::unique_ptr<webrtc::RtpTransport> CreateUnencryptedTransport(
      rtc::PacketTransportInternal* rtp_packet_transport,
      rtc::PacketTransportInternal* rtcp_packet_transport) {
    auto rtp_transport = std::make_unique<webrtc::RtpTransport>(
        rtcp_packet_transport == nullptr, field_trials_);

    SendTask(network_thread_,
             [&rtp_transport, rtp_packet_transport, rtcp_packet_transport] {
               rtp_transport->SetRtpPacketTransport(rtp_packet_transport);
               if (rtcp_packet_transport) {
                 rtp_transport->SetRtcpPacketTransport(rtcp_packet_transport);
               }
             });
    return rtp_transport;
  }

  std::unique_ptr<webrtc::DtlsSrtpTransport> CreateDtlsSrtpTransport(
      cricket::DtlsTransportInternal* rtp_dtls_transport,
      cricket::DtlsTransportInternal* rtcp_dtls_transport) {
    auto dtls_srtp_transport = std::make_unique<webrtc::DtlsSrtpTransport>(
        rtcp_dtls_transport == nullptr, field_trials_);

    SendTask(network_thread_,
             [&dtls_srtp_transport, rtp_dtls_transport, rtcp_dtls_transport] {
               dtls_srtp_transport->SetDtlsTransports(rtp_dtls_transport,
                                                      rtcp_dtls_transport);
             });
    return dtls_srtp_transport;
  }

  void ConnectFakeTransports() {
    SendTask(network_thread_, [this] {
      bool asymmetric = false;
      // Depending on test flags, could be using DTLS or raw packet transport.
      if (fake_rtp_dtls_transport1_ && fake_rtp_dtls_transport2_) {
        fake_rtp_dtls_transport1_->SetDestination(
            fake_rtp_dtls_transport2_.get(), asymmetric);
      }
      if (fake_rtcp_dtls_transport1_ && fake_rtcp_dtls_transport2_) {
        fake_rtcp_dtls_transport1_->SetDestination(
            fake_rtcp_dtls_transport2_.get(), asymmetric);
      }
      if (fake_rtp_packet_transport1_ && fake_rtp_packet_transport2_) {
        fake_rtp_packet_transport1_->SetDestination(
            fake_rtp_packet_transport2_.get(), asymmetric);
      }
      if (fake_rtcp_packet_transport1_ && fake_rtcp_packet_transport2_) {
        fake_rtcp_packet_transport1_->SetDestination(
            fake_rtcp_packet_transport2_.get(), asymmetric);
      }
    });
    // The transport becoming writable will asynchronously update the send state
    // on the worker thread; since this test uses the main thread as the worker
    // thread, we must process the message queue for this to occur.
    WaitForThreads();
  }

  bool SendInitiate() {
    std::string err;
    bool result = channel1_->SetLocalContent(&local_media_content1_,
                                             SdpType::kOffer, err);
    if (result) {
      channel1_->Enable(true);
      FlushCurrentThread();
      result = channel2_->SetRemoteContent(&remote_media_content1_,
                                           SdpType::kOffer, err);
      if (result) {
        ConnectFakeTransports();
        result = channel2_->SetLocalContent(&local_media_content2_,
                                            SdpType::kAnswer, err);
      }
    }
    return result;
  }

  bool SendAccept() {
    channel2_->Enable(true);
    FlushCurrentThread();
    std::string err;
    return channel1_->SetRemoteContent(&remote_media_content2_,
                                       SdpType::kAnswer, err);
  }

  bool SendOffer() {
    std::string err;
    bool result = channel1_->SetLocalContent(&local_media_content1_,
                                             SdpType::kOffer, err);
    if (result) {
      channel1_->Enable(true);
      result = channel2_->SetRemoteContent(&remote_media_content1_,
                                           SdpType::kOffer, err);
    }
    return result;
  }

  bool SendProvisionalAnswer() {
    std::string err;
    bool result = channel2_->SetLocalContent(&local_media_content2_,
                                             SdpType::kPrAnswer, err);
    if (result) {
      channel2_->Enable(true);
      result = channel1_->SetRemoteContent(&remote_media_content2_,
                                           SdpType::kPrAnswer, err);
      ConnectFakeTransports();
    }
    return result;
  }

  bool SendFinalAnswer() {
    std::string err;
    bool result = channel2_->SetLocalContent(&local_media_content2_,
                                             SdpType::kAnswer, err);
    if (result) {
      result = channel1_->SetRemoteContent(&remote_media_content2_,
                                           SdpType::kAnswer, err);
    }
    return result;
  }

  void SendRtp(typename T::MediaSendChannel* media_channel, rtc::Buffer data) {
    network_thread_->PostTask(webrtc::SafeTask(
        network_thread_safety_, [media_channel, data = std::move(data)]() {
          media_channel->SendPacket(data.data(), data.size(),
                                    rtc::PacketOptions());
        }));
  }

  void SendRtp1() {
    SendRtp1(rtc::Buffer(rtp_packet_.data(), rtp_packet_.size()));
  }

  void SendRtp1(rtc::Buffer data) {
    SendRtp(media_send_channel1_impl(), std::move(data));
  }

  void SendRtp2() {
    SendRtp2(rtc::Buffer(rtp_packet_.data(), rtp_packet_.size()));
  }

  void SendRtp2(rtc::Buffer data) {
    SendRtp(media_send_channel2_impl(), std::move(data));
  }

  // Methods to send custom data.
  void SendCustomRtp1(uint32_t ssrc, int sequence_number, int pl_type = -1) {
    SendRtp1(CreateRtpData(ssrc, sequence_number, pl_type));
  }
  void SendCustomRtp2(uint32_t ssrc, int sequence_number, int pl_type = -1) {
    SendRtp2(CreateRtpData(ssrc, sequence_number, pl_type));
  }

  bool CheckRtp1() {
    return media_receive_channel1_impl()->CheckRtp(rtp_packet_.data(),
                                                   rtp_packet_.size());
  }
  bool CheckRtp2() {
    return media_receive_channel2_impl()->CheckRtp(rtp_packet_.data(),
                                                   rtp_packet_.size());
  }
  // Methods to check custom data.
  bool CheckCustomRtp1(uint32_t ssrc, int sequence_number, int pl_type = -1) {
    rtc::Buffer data = CreateRtpData(ssrc, sequence_number, pl_type);
    return media_receive_channel1_impl()->CheckRtp(data.data(), data.size());
  }
  bool CheckCustomRtp2(uint32_t ssrc, int sequence_number, int pl_type = -1) {
    rtc::Buffer data = CreateRtpData(ssrc, sequence_number, pl_type);
    return media_receive_channel2_impl()->CheckRtp(data.data(), data.size());
  }
  rtc::Buffer CreateRtpData(uint32_t ssrc, int sequence_number, int pl_type) {
    rtc::Buffer data(rtp_packet_.data(), rtp_packet_.size());
    // Set SSRC in the rtp packet copy.
    rtc::SetBE32(data.data() + 8, ssrc);
    rtc::SetBE16(data.data() + 2, sequence_number);
    if (pl_type >= 0) {
      rtc::Set8(data.data(), 1, static_cast<uint8_t>(pl_type));
    }
    return data;
  }

  bool CheckNoRtp1() { return media_send_channel1_impl()->CheckNoRtp(); }
  bool CheckNoRtp2() { return media_send_channel2_impl()->CheckNoRtp(); }

  void CreateContent(int flags,
                     const cricket::Codec& audio_codec,
                     const cricket::Codec& video_codec,
                     typename T::Content* content) {
    // overridden in specialized classes
  }
  void CopyContent(const typename T::Content& source,
                   typename T::Content* content) {
    // overridden in specialized classes
  }

  // Creates a MediaContent with one stream.
  // kPcmuCodec is used as audio codec and kH264Codec is used as video codec.
  typename T::Content* CreateMediaContentWithStream(uint32_t ssrc) {
    typename T::Content* content = new typename T::Content();
    CreateContent(0, kPcmuCodec, kH264Codec, content);
    AddLegacyStreamInContent(ssrc, 0, content);
    return content;
  }

  // Will manage the lifetime of a CallThread, making sure it's
  // destroyed before this object goes out of scope.
  class ScopedCallThread {
   public:
    explicit ScopedCallThread(absl::AnyInvocable<void() &&> functor)
        : thread_(rtc::Thread::Create()) {
      thread_->Start();
      thread_->PostTask(std::move(functor));
    }

    ~ScopedCallThread() { thread_->Stop(); }

    rtc::Thread* thread() { return thread_.get(); }

   private:
    std::unique_ptr<rtc::Thread> thread_;
  };

  cricket::CandidatePairInterface* last_selected_candidate_pair() {
    return last_selected_candidate_pair_;
  }

  void AddLegacyStreamInContent(uint32_t ssrc,
                                int flags,
                                typename T::Content* content) {
    // Base implementation.
  }

  // Utility method that calls BaseChannel::srtp_active() on the network thread
  // and returns the result. The `srtp_active()` state is maintained on the
  // network thread, which callers need to factor in.
  bool IsSrtpActive(std::unique_ptr<typename T::Channel>& channel) {
    RTC_DCHECK(channel.get());
    bool result;
    SendTask(network_thread_, [&] { result = channel->srtp_active(); });
    return result;
  }

  // Returns true iff the transport is set for a channel and rtcp_mux_enabled()
  // returns true.
  bool IsRtcpMuxEnabled(std::unique_ptr<typename T::Channel>& channel) {
    RTC_DCHECK(channel.get());
    bool result;
    SendTask(network_thread_, [&] {
      result = channel->rtp_transport() &&
               channel->rtp_transport()->rtcp_mux_enabled();
    });
    return result;
  }

  // Tests that can be used by derived classes.

  // Basic sanity check.
  void TestInit() {
    CreateChannels(0, 0);
    EXPECT_FALSE(IsSrtpActive(channel1_));
    EXPECT_FALSE(media_send_channel1_impl()->sending());
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel1_impl()->playout());
    }
    EXPECT_TRUE(media_send_channel1_impl()->send_codecs().empty());
    EXPECT_TRUE(media_receive_channel1_impl()->recv_streams().empty());
    EXPECT_TRUE(media_send_channel1_impl()->rtp_packets().empty());
    // Basic sanity test for send and receive channel objects
    EXPECT_EQ(channel1_->media_send_channel()->media_type(),
              media_send_channel1_impl()->media_type());
    EXPECT_EQ(channel1_->media_receive_channel()->media_type(),
              media_receive_channel1_impl()->media_type());
    EXPECT_EQ(channel1_->media_send_channel()->media_type(),
              channel1_->media_receive_channel()->media_type());
  }

  // Test that SetLocalContent and SetRemoteContent properly configure
  // the codecs.
  void TestSetContents() {
    CreateChannels(0, 0);
    typename T::Content content;
    CreateContent(0, kPcmuCodec, kH264Codec, &content);
    std::string err;
    EXPECT_TRUE(channel1_->SetLocalContent(&content, SdpType::kOffer, err));
    EXPECT_EQ(0U, media_send_channel1_impl()->send_codecs().size());
    EXPECT_TRUE(channel1_->SetRemoteContent(&content, SdpType::kAnswer, err));
    ASSERT_EQ(1U, media_send_channel1_impl()->send_codecs().size());
    EXPECT_EQ(content.codecs()[0],
              media_send_channel1_impl()->send_codecs()[0]);
  }

  // Test that SetLocalContent and SetRemoteContent properly configure
  // extmap-allow-mixed.
  void TestSetContentsExtmapAllowMixedCaller(bool offer, bool answer) {
    // For a caller, SetLocalContent() is called first with an offer and next
    // SetRemoteContent() is called with the answer.
    CreateChannels(0, 0);
    typename T::Content content;
    CreateContent(0, kPcmuCodec, kH264Codec, &content);
    auto offer_enum = offer ? (T::Content::kSession) : (T::Content::kNo);
    auto answer_enum = answer ? (T::Content::kSession) : (T::Content::kNo);
    content.set_extmap_allow_mixed_enum(offer_enum);
    std::string err;
    EXPECT_TRUE(channel1_->SetLocalContent(&content, SdpType::kOffer, err));
    content.set_extmap_allow_mixed_enum(answer_enum);
    EXPECT_TRUE(channel1_->SetRemoteContent(&content, SdpType::kAnswer, err));
    EXPECT_EQ(answer, media_send_channel1_impl()->ExtmapAllowMixed());
  }
  void TestSetContentsExtmapAllowMixedCallee(bool offer, bool answer) {
    // For a callee, SetRemoteContent() is called first with an offer and next
    // SetLocalContent() is called with the answer.
    CreateChannels(0, 0);
    typename T::Content content;
    CreateContent(0, kPcmuCodec, kH264Codec, &content);
    auto offer_enum = offer ? (T::Content::kSession) : (T::Content::kNo);
    auto answer_enum = answer ? (T::Content::kSession) : (T::Content::kNo);
    content.set_extmap_allow_mixed_enum(offer_enum);
    std::string err;
    EXPECT_TRUE(channel1_->SetRemoteContent(&content, SdpType::kOffer, err));
    content.set_extmap_allow_mixed_enum(answer_enum);
    EXPECT_TRUE(channel1_->SetLocalContent(&content, SdpType::kAnswer, err));
    EXPECT_EQ(answer, media_send_channel1()->ExtmapAllowMixed());
  }

  // Test that SetLocalContent and SetRemoteContent properly deals
  // with an empty offer.
  void TestSetContentsNullOffer() {
    CreateChannels(0, 0);
    typename T::Content content;
    std::string err;
    EXPECT_TRUE(channel1_->SetLocalContent(&content, SdpType::kOffer, err));
    CreateContent(0, kPcmuCodec, kH264Codec, &content);
    EXPECT_EQ(0U, media_send_channel1_impl()->send_codecs().size());
    EXPECT_TRUE(channel1_->SetRemoteContent(&content, SdpType::kAnswer, err));
    ASSERT_EQ(1U, media_send_channel1_impl()->send_codecs().size());
    EXPECT_EQ(content.codecs()[0],
              media_send_channel1_impl()->send_codecs()[0]);
  }

  // Test that SetLocalContent and SetRemoteContent properly set RTCP
  // mux.
  void TestSetContentsRtcpMux() {
    CreateChannels(0, 0);
    typename T::Content content;
    CreateContent(0, kPcmuCodec, kH264Codec, &content);
    // Both sides agree on mux. Should no longer be a separate RTCP channel.
    content.set_rtcp_mux(true);
    std::string err;
    EXPECT_TRUE(channel1_->SetLocalContent(&content, SdpType::kOffer, err));
    EXPECT_TRUE(channel1_->SetRemoteContent(&content, SdpType::kAnswer, err));
    // Only initiator supports mux. Should still have a separate RTCP channel.
    EXPECT_TRUE(channel2_->SetLocalContent(&content, SdpType::kOffer, err));
    content.set_rtcp_mux(false);
    EXPECT_TRUE(channel2_->SetRemoteContent(&content, SdpType::kAnswer, err));
  }

  // Test that SetLocalContent and SetRemoteContent properly
  // handles adding and removing StreamParams when the action is a full
  // SdpType::kOffer / SdpType::kAnswer.
  void TestChangeStreamParamsInContent() {
    cricket::StreamParams stream1;
    stream1.id = "stream1";
    stream1.ssrcs.push_back(kSsrc1);
    stream1.cname = "stream1_cname";

    cricket::StreamParams stream2;
    stream2.id = "stream2";
    stream2.ssrcs.push_back(kSsrc2);
    stream2.cname = "stream2_cname";

    // Setup a call where channel 1 send `stream1` to channel 2.
    CreateChannels(0, 0);
    typename T::Content content1;
    CreateContent(0, kPcmuCodec, kH264Codec, &content1);
    content1.AddStream(stream1);
    std::string err;
    EXPECT_TRUE(channel1_->SetLocalContent(&content1, SdpType::kOffer, err));
    channel1_->Enable(true);
    EXPECT_EQ(1u, media_send_channel1_impl()->send_streams().size());

    EXPECT_TRUE(channel2_->SetRemoteContent(&content1, SdpType::kOffer, err));
    EXPECT_EQ(1u, media_receive_channel2_impl()->recv_streams().size());
    ConnectFakeTransports();

    // Channel 2 do not send anything.
    typename T::Content content2;
    CreateContent(0, kPcmuCodec, kH264Codec, &content2);
    EXPECT_TRUE(channel1_->SetRemoteContent(&content2, SdpType::kAnswer, err));
    EXPECT_EQ(0u, media_receive_channel1_impl()->recv_streams().size());
    EXPECT_TRUE(channel2_->SetLocalContent(&content2, SdpType::kAnswer, err));
    channel2_->Enable(true);
    EXPECT_EQ(0u, media_send_channel2_impl()->send_streams().size());

    SendCustomRtp1(kSsrc1, 0);
    WaitForThreads();
    EXPECT_TRUE(CheckCustomRtp2(kSsrc1, 0));

    // Let channel 2 update the content by sending `stream2` and enable SRTP.
    typename T::Content content3;
    CreateContent(0, kPcmuCodec, kH264Codec, &content3);
    content3.AddStream(stream2);
    EXPECT_TRUE(channel2_->SetLocalContent(&content3, SdpType::kOffer, err));
    ASSERT_EQ(1u, media_send_channel2_impl()->send_streams().size());
    EXPECT_EQ(stream2, media_send_channel2_impl()->send_streams()[0]);

    EXPECT_TRUE(channel1_->SetRemoteContent(&content3, SdpType::kOffer, err));
    ASSERT_EQ(1u, media_receive_channel1_impl()->recv_streams().size());
    EXPECT_EQ(stream2, media_receive_channel1_impl()->recv_streams()[0]);

    // Channel 1 replies but stop sending stream1.
    typename T::Content content4;
    CreateContent(0, kPcmuCodec, kH264Codec, &content4);
    EXPECT_TRUE(channel1_->SetLocalContent(&content4, SdpType::kAnswer, err));
    EXPECT_EQ(0u, media_send_channel1_impl()->send_streams().size());

    EXPECT_TRUE(channel2_->SetRemoteContent(&content4, SdpType::kAnswer, err));
    EXPECT_EQ(0u, media_receive_channel2_impl()->recv_streams().size());

    SendCustomRtp2(kSsrc2, 0);
    WaitForThreads();
    EXPECT_TRUE(CheckCustomRtp1(kSsrc2, 0));
  }

  // Test that we only start playout and sending at the right times.
  void TestPlayoutAndSendingStates() {
    CreateChannels(0, 0);
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel1_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel1_impl()->sending());
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel2_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel2_impl()->sending());
    channel1_->Enable(true);
    FlushCurrentThread();
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel1_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel1_impl()->sending());
    std::string err;
    EXPECT_TRUE(channel1_->SetLocalContent(&local_media_content1_,
                                           SdpType::kOffer, err));
    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel1_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel1_impl()->sending());
    EXPECT_TRUE(channel2_->SetRemoteContent(&local_media_content1_,
                                            SdpType::kOffer, err));
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel2_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel2_impl()->sending());
    EXPECT_TRUE(channel2_->SetLocalContent(&local_media_content2_,
                                           SdpType::kAnswer, err));
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel2_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel2_impl()->sending());
    ConnectFakeTransports();
    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel1_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel1_impl()->sending());
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel2_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel2_impl()->sending());
    channel2_->Enable(true);
    FlushCurrentThread();
    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel2_impl()->playout());
    }
    EXPECT_TRUE(media_send_channel2_impl()->sending());
    EXPECT_TRUE(channel1_->SetRemoteContent(&local_media_content2_,
                                            SdpType::kAnswer, err));
    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel1_impl()->playout());
    }
    EXPECT_TRUE(media_send_channel1_impl()->sending());
  }

  // Test that changing the MediaContentDirection in the local and remote
  // session description start playout and sending at the right time.
  void TestMediaContentDirection() {
    CreateChannels(0, 0);
    typename T::Content content1;
    CreateContent(0, kPcmuCodec, kH264Codec, &content1);
    typename T::Content content2;
    CreateContent(0, kPcmuCodec, kH264Codec, &content2);
    // Set `content2` to be InActive.
    content2.set_direction(RtpTransceiverDirection::kInactive);

    channel1_->Enable(true);
    channel2_->Enable(true);
    FlushCurrentThread();
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel1_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel1_impl()->sending());
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel2_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel2_impl()->sending());

    std::string err;
    EXPECT_TRUE(channel1_->SetLocalContent(&content1, SdpType::kOffer, err));
    EXPECT_TRUE(channel2_->SetRemoteContent(&content1, SdpType::kOffer, err));
    EXPECT_TRUE(channel2_->SetLocalContent(&content2, SdpType::kPrAnswer, err));
    EXPECT_TRUE(
        channel1_->SetRemoteContent(&content2, SdpType::kPrAnswer, err));
    ConnectFakeTransports();

    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel1_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel1_impl()->sending());  // remote InActive
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel2_impl()->playout());  // local InActive
    }
    EXPECT_FALSE(media_send_channel2_impl()->sending());  // local InActive

    // Update `content2` to be RecvOnly.
    content2.set_direction(RtpTransceiverDirection::kRecvOnly);
    EXPECT_TRUE(channel2_->SetLocalContent(&content2, SdpType::kPrAnswer, err));
    EXPECT_TRUE(
        channel1_->SetRemoteContent(&content2, SdpType::kPrAnswer, err));

    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel1_impl()->playout());
    }
    EXPECT_TRUE(media_send_channel1_impl()->sending());
    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel2_impl()->playout());  // local RecvOnly
    }
    EXPECT_FALSE(media_send_channel2_impl()->sending());  // local RecvOnly

    // Update `content2` to be SendRecv.
    content2.set_direction(RtpTransceiverDirection::kSendRecv);
    EXPECT_TRUE(channel2_->SetLocalContent(&content2, SdpType::kAnswer, err));
    EXPECT_TRUE(channel1_->SetRemoteContent(&content2, SdpType::kAnswer, err));

    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel1_impl()->playout());
    }
    EXPECT_TRUE(media_send_channel1_impl()->sending());
    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel2_impl()->playout());
    }
    EXPECT_TRUE(media_send_channel2_impl()->sending());

    // Update `content2` to be inactive on the receiver while sending at the
    // sender.
    content2.set_direction(RtpTransceiverDirection::kInactive);
    EXPECT_TRUE(channel1_->SetLocalContent(&content1, SdpType::kOffer, err));
    EXPECT_TRUE(channel2_->SetRemoteContent(&content1, SdpType::kOffer, err));
    EXPECT_TRUE(channel2_->SetLocalContent(&content2, SdpType::kAnswer, err));
    content2.set_direction(RtpTransceiverDirection::kRecvOnly);
    EXPECT_TRUE(channel1_->SetRemoteContent(&content2, SdpType::kAnswer, err));
    if (verify_playout_) {
      EXPECT_FALSE(media_receive_channel2_impl()->playout());
    }
    EXPECT_TRUE(media_send_channel1_impl()->sending());

    // Re-enable `content2`.
    content2.set_direction(RtpTransceiverDirection::kSendRecv);
    EXPECT_TRUE(channel1_->SetLocalContent(&content1, SdpType::kOffer, err));
    EXPECT_TRUE(channel2_->SetRemoteContent(&content1, SdpType::kOffer, err));
    EXPECT_TRUE(channel2_->SetLocalContent(&content2, SdpType::kAnswer, err));
    EXPECT_TRUE(channel1_->SetRemoteContent(&content2, SdpType::kAnswer, err));
    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel2_impl()->playout());
    }
    EXPECT_TRUE(media_send_channel1_impl()->sending());
  }

  // Tests that when the transport channel signals a candidate pair change
  // event, the media channel will receive a call on the network route change.
  void TestNetworkRouteChanges() {
    static constexpr uint16_t kLocalNetId = 1;
    static constexpr uint16_t kRemoteNetId = 2;
    static constexpr int kLastPacketId = 100;
    // Ipv4(20) + UDP(8).
    static constexpr int kTransportOverheadPerPacket = 28;
    static constexpr int kSrtpOverheadPerPacket = 10;

    CreateChannels(DTLS, DTLS);
    SendInitiate();

    typename T::MediaSendChannel* media_send_channel1_impl =
        this->media_send_channel1_impl();
    ASSERT_TRUE(media_send_channel1_impl);

    // Need to wait for the threads before calling
    // `set_num_network_route_changes` because the network route would be set
    // when creating the channel.
    WaitForThreads();
    media_send_channel1_impl->set_num_network_route_changes(0);
    SendTask(network_thread_, [this] {
      rtc::NetworkRoute network_route;
      // The transport channel becomes disconnected.
      fake_rtp_dtls_transport1_->ice_transport()->SignalNetworkRouteChanged(
          std::optional<rtc::NetworkRoute>(network_route));
    });
    WaitForThreads();
    EXPECT_EQ(1, media_send_channel1_impl->num_network_route_changes());
    EXPECT_FALSE(media_send_channel1_impl->last_network_route().connected);
    media_send_channel1_impl->set_num_network_route_changes(0);

    SendTask(network_thread_, [this] {
      rtc::NetworkRoute network_route;
      network_route.connected = true;
      network_route.local =
          rtc::RouteEndpoint::CreateWithNetworkId(kLocalNetId);
      network_route.remote =
          rtc::RouteEndpoint::CreateWithNetworkId(kRemoteNetId);
      network_route.last_sent_packet_id = kLastPacketId;
      network_route.packet_overhead = kTransportOverheadPerPacket;
      // The transport channel becomes connected.
      fake_rtp_dtls_transport1_->ice_transport()->SignalNetworkRouteChanged(

          std::optional<rtc::NetworkRoute>(network_route));
    });
    WaitForThreads();
    EXPECT_EQ(1, media_send_channel1_impl->num_network_route_changes());
    EXPECT_TRUE(media_send_channel1_impl->last_network_route().connected);
    EXPECT_EQ(
        kLocalNetId,
        media_send_channel1_impl->last_network_route().local.network_id());
    EXPECT_EQ(
        kRemoteNetId,
        media_send_channel1_impl->last_network_route().remote.network_id());
    EXPECT_EQ(
        kLastPacketId,
        media_send_channel1_impl->last_network_route().last_sent_packet_id);
    EXPECT_EQ(kTransportOverheadPerPacket + kSrtpOverheadPerPacket,
              media_send_channel1_impl->transport_overhead_per_packet());
  }

  // Test setting up a call.
  void TestCallSetup() {
    CreateChannels(0, 0);
    EXPECT_FALSE(IsSrtpActive(channel1_));
    EXPECT_TRUE(SendInitiate());
    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel1_impl()->playout());
    }
    EXPECT_FALSE(media_send_channel1_impl()->sending());
    EXPECT_TRUE(SendAccept());
    EXPECT_FALSE(IsSrtpActive(channel1_));
    EXPECT_TRUE(media_send_channel1_impl()->sending());
    EXPECT_EQ(1U, media_send_channel1_impl()->send_codecs().size());
    if (verify_playout_) {
      EXPECT_TRUE(media_receive_channel2_impl()->playout());
    }
    EXPECT_TRUE(media_send_channel2_impl()->sending());
    EXPECT_EQ(1U, media_send_channel2_impl()->send_codecs().size());
  }

  // Send voice RTP data to the other side and ensure it gets there.
  void SendRtpToRtp() {
    CreateChannels(RTCP_MUX, RTCP_MUX);
    EXPECT_TRUE(SendInitiate());
    EXPECT_TRUE(SendAccept());
    EXPECT_TRUE(IsRtcpMuxEnabled(channel1_));
    EXPECT_TRUE(IsRtcpMuxEnabled(channel2_));
    SendRtp1();
    SendRtp2();
    WaitForThreads();
    EXPECT_TRUE(CheckRtp1());
    EXPECT_TRUE(CheckRtp2());
    EXPECT_TRUE(CheckNoRtp1());
    EXPECT_TRUE(CheckNoRtp2());
  }

  void TestDeinit() {
    CreateChannels(0, 0);
    EXPECT_TRUE(SendInitiate());
    EXPECT_TRUE(SendAccept());
    SendRtp1();
    SendRtp2();

    DeinitChannels();

    // Do not wait, destroy channels.
    channel1_.reset(nullptr);
    channel2_.reset(nullptr);
  }

  void SendDtlsSrtpToDtlsSrtp(int flags1, int flags2) {
    CreateChannels(flags1 | DTLS, flags2 | DTLS);
    EXPECT_FALSE(IsSrtpActive(channel1_));
    EXPECT_FALSE(IsSrtpActive(channel2_));
    EXPECT_TRUE(SendInitiate());
    WaitForThreads();
    EXPECT_TRUE(SendAccept());
    EXPECT_TRUE(IsSrtpActive(channel1_));
    EXPECT_TRUE(IsSrtpActive(channel2_));
    SendRtp1();
    SendRtp2();
    WaitForThreads();
    EXPECT_TRUE(CheckRtp1());
    EXPECT_TRUE(CheckRtp2());
    EXPECT_TRUE(CheckNoRtp1());
    EXPECT_TRUE(CheckNoRtp2());
  }

  // Test that we can send and receive early media when a provisional answer is
  // sent and received. The test uses SRTP, RTCP mux and SSRC mux.
  void SendEarlyMediaUsingRtcpMuxSrtp() {
    int sequence_number1_1 = 0, sequence_number2_2 = 0;

    CreateChannels(SSRC_MUX | RTCP_MUX | DTLS, SSRC_MUX | RTCP_MUX | DTLS);
    EXPECT_TRUE(SendOffer());
    EXPECT_TRUE(SendProvisionalAnswer());
    EXPECT_TRUE(IsSrtpActive(channel1_));
    EXPECT_TRUE(IsSrtpActive(channel2_));
    EXPECT_TRUE(IsRtcpMuxEnabled(channel1_));
    EXPECT_TRUE(IsRtcpMuxEnabled(channel2_));
    WaitForThreads();  // Wait for 'sending' flag go through network thread.
    SendCustomRtp1(kSsrc1, ++sequence_number1_1);
    WaitForThreads();
    EXPECT_TRUE(CheckCustomRtp2(kSsrc1, sequence_number1_1));

    // Send packets from callee and verify that it is received.
    SendCustomRtp2(kSsrc2, ++sequence_number2_2);
    WaitForThreads();
    EXPECT_TRUE(CheckCustomRtp1(kSsrc2, sequence_number2_2));

    // Complete call setup and ensure everything is still OK.
    EXPECT_TRUE(SendFinalAnswer());
    EXPECT_TRUE(IsSrtpActive(channel1_));
    EXPECT_TRUE(IsSrtpActive(channel2_));
    SendCustomRtp1(kSsrc1, ++sequence_number1_1);
    SendCustomRtp2(kSsrc2, ++sequence_number2_2);
    WaitForThreads();
    EXPECT_TRUE(CheckCustomRtp2(kSsrc1, sequence_number1_1));
    EXPECT_TRUE(CheckCustomRtp1(kSsrc2, sequence_number2_2));
  }

  // Test that we properly send RTP without SRTP from a thread.
  void SendRtpToRtpOnThread() {
    CreateChannels(0, 0);
    EXPECT_TRUE(SendInitiate());
    EXPECT_TRUE(SendAccept());
    ScopedCallThread send_rtp1([this] { SendRtp1(); });
    ScopedCallThread send_rtp2([this] { SendRtp2(); });
    rtc::Thread* involved_threads[] = {send_rtp1.thread(), send_rtp2.thread()};
    WaitForThreads(involved_threads);
    EXPECT_TRUE(CheckRtp1());
    EXPECT_TRUE(CheckRtp2());
    EXPECT_TRUE(CheckNoRtp1());
    EXPECT_TRUE(CheckNoRtp2());
  }

  // Test that the mediachannel retains its sending state after the transport
  // becomes non-writable.
  void SendWithWritabilityLoss() {
    CreateChannels(RTCP_MUX, RTCP_MUX);
    EXPECT_TRUE(SendInitiate());
    EXPECT_TRUE(SendAccept());
    EXPECT_TRUE(IsRtcpMuxEnabled(channel1_));
    EXPECT_TRUE(IsRtcpMuxEnabled(channel2_));
    SendRtp1();
    SendRtp2();
    WaitForThreads();
    EXPECT_TRUE(CheckRtp1());
    EXPECT_TRUE(CheckRtp2());
    EXPECT_TRUE(CheckNoRtp1());
    EXPECT_TRUE(CheckNoRtp2());

    // Lose writability, which should fail.
    SendTask(network_thread_,
             [this] { fake_rtp_dtls_transport1_->SetWritable(false); });
    SendRtp1();
    SendRtp2();
    WaitForThreads();
    EXPECT_TRUE(CheckRtp1());
    EXPECT_TRUE(CheckNoRtp2());

    // Regain writability
    SendTask(network_thread_,
             [this] { fake_rtp_dtls_transport1_->SetWritable(true); });
    EXPECT_TRUE(media_send_channel1_impl()->sending());
    SendRtp1();
    SendRtp2();
    WaitForThreads();
    EXPECT_TRUE(CheckRtp1());
    EXPECT_TRUE(CheckRtp2());
    EXPECT_TRUE(CheckNoRtp1());
    EXPECT_TRUE(CheckNoRtp2());

    // Lose writability completely
    SendTask(network_thread_, [this] {
      bool asymmetric = true;
      fake_rtp_dtls_transport1_->SetDestination(nullptr, asymmetric);
    });
    EXPECT_TRUE(media_send_channel1_impl()->sending());

    // Should fail also.
    SendRtp1();
    SendRtp2();
    WaitForThreads();
    EXPECT_TRUE(CheckRtp1());
    EXPECT_TRUE(CheckNoRtp2());
    EXPECT_TRUE(CheckNoRtp1());

    // Gain writability back
    SendTask(network_thread_, [this] {
      bool asymmetric = true;
      fake_rtp_dtls_transport1_->SetDestination(fake_rtp_dtls_transport2_.get(),
                                                asymmetric);
    });
    EXPECT_TRUE(media_send_channel1_impl()->sending());
    SendRtp1();
    SendRtp2();
    WaitForThreads();
    EXPECT_TRUE(CheckRtp1());
    EXPECT_TRUE(CheckRtp2());
    EXPECT_TRUE(CheckNoRtp1());
    EXPECT_TRUE(CheckNoRtp2());
  }

  void SendBundleToBundle(const int* pl_types,
                          int len,
                          bool rtcp_mux,
                          bool secure) {
    ASSERT_EQ(2, len);
    int sequence_number1_1 = 0, sequence_number2_2 = 0;
    // Only pl_type1 was added to the bundle filter for both `channel1_`
    // and `channel2_`.
    int pl_type1 = pl_types[0];
    int pl_type2 = pl_types[1];
    int flags = SSRC_MUX;
    if (secure)
      flags |= DTLS;
    if (rtcp_mux) {
      flags |= RTCP_MUX;
    }
    CreateChannels(flags, flags);
    EXPECT_TRUE(SendInitiate());
    EXPECT_TRUE(SendAccept());

    // Both channels can receive pl_type1 only.
    SendCustomRtp1(kSsrc1, ++sequence_number1_1, pl_type1);
    SendCustomRtp2(kSsrc2, ++sequence_number2_2, pl_type1);
    WaitForThreads();
    EXPECT_TRUE(CheckCustomRtp2(kSsrc1, sequence_number1_1, pl_type1));
    EXPECT_TRUE(CheckCustomRtp1(kSsrc2, sequence_number2_2, pl_type1));
    EXPECT_TRUE(CheckNoRtp1());
    EXPECT_TRUE(CheckNoRtp2());

    SendCustomRtp1(kSsrc3, ++sequence_number1_1, pl_type2);
    SendCustomRtp2(kSsrc4, ++sequence_number2_2, pl_type2);
    WaitForThreads();
    EXPECT_FALSE(CheckCustomRtp2(kSsrc3, sequence_number1_1, pl_type2));
    EXPECT_FALSE(CheckCustomRtp1(kSsrc4, sequence_number2_2, pl_type2));
  }

  void TestSetContentFailure() {
    CreateChannels(0, 0);

    std::string err;
    std::unique_ptr<typename T::Content> content(
        CreateMediaContentWithStream(1));

    media_receive_channel1_impl()->set_fail_set_recv_codecs(true);
    EXPECT_FALSE(
        channel1_->SetLocalContent(content.get(), SdpType::kOffer, err));
    EXPECT_FALSE(
        channel1_->SetLocalContent(content.get(), SdpType::kAnswer, err));

    media_send_channel1_impl()->set_fail_set_send_codecs(true);
    EXPECT_FALSE(
        channel1_->SetRemoteContent(content.get(), SdpType::kOffer, err));

    media_send_channel1_impl()->set_fail_set_send_codecs(true);
    EXPECT_FALSE(
        channel1_->SetRemoteContent(content.get(), SdpType::kAnswer, err));
  }

  void TestSendTwoOffers() {
    CreateChannels(0, 0);

    std::string err;
    std::unique_ptr<typename T::Content> content1(
        CreateMediaContentWithStream(1));
    EXPECT_TRUE(
        channel1_->SetLocalContent(content1.get(), SdpType::kOffer, err));
    EXPECT_TRUE(media_send_channel1_impl()->HasSendStream(1));

    std::unique_ptr<typename T::Content> content2(
        CreateMediaContentWithStream(2));
    EXPECT_TRUE(
        channel1_->SetLocalContent(content2.get(), SdpType::kOffer, err));
    EXPECT_FALSE(media_send_channel1_impl()->HasSendStream(1));
    EXPECT_TRUE(media_send_channel1_impl()->HasSendStream(2));
  }

  void TestReceiveTwoOffers() {
    CreateChannels(0, 0);

    std::string err;
    std::unique_ptr<typename T::Content> content1(
        CreateMediaContentWithStream(1));
    EXPECT_TRUE(
        channel1_->SetRemoteContent(content1.get(), SdpType::kOffer, err));
    EXPECT_TRUE(media_receive_channel1_impl()->HasRecvStream(1));

    std::unique_ptr<typename T::Content> content2(
        CreateMediaContentWithStream(2));
    EXPECT_TRUE(
        channel1_->SetRemoteContent(content2.get(), SdpType::kOffer, err));
    EXPECT_FALSE(media_receive_channel1_impl()->HasRecvStream(1));
    EXPECT_TRUE(media_receive_channel1_impl()->HasRecvStream(2));
  }

  void TestSendPrAnswer() {
    CreateChannels(0, 0);

    std::string err;
    // Receive offer
    std::unique_ptr<typename T::Content> content1(
        CreateMediaContentWithStream(1));
    EXPECT_TRUE(
        channel1_->SetRemoteContent(content1.get(), SdpType::kOffer, err));
    EXPECT_TRUE(media_receive_channel1_impl()->HasRecvStream(1));

    // Send PR answer
    std::unique_ptr<typename T::Content> content2(
        CreateMediaContentWithStream(2));
    EXPECT_TRUE(
        channel1_->SetLocalContent(content2.get(), SdpType::kPrAnswer, err));
    EXPECT_TRUE(media_receive_channel1_impl()->HasRecvStream(1));
    EXPECT_TRUE(media_send_channel1_impl()->HasSendStream(2));

    // Send answer
    std::unique_ptr<typename T::Content> content3(
        CreateMediaContentWithStream(3));
    EXPECT_TRUE(
        channel1_->SetLocalContent(content3.get(), SdpType::kAnswer, err));
    EXPECT_TRUE(media_receive_channel1_impl()->HasRecvStream(1));
    EXPECT_FALSE(media_send_channel1_impl()->HasSendStream(2));
    EXPECT_TRUE(media_send_channel1_impl()->HasSendStream(3));
  }

  void TestReceivePrAnswer() {
    CreateChannels(0, 0);

    std::string err;
    // Send offer
    std::unique_ptr<typename T::Content> content1(
        CreateMediaContentWithStream(1));
    EXPECT_TRUE(
        channel1_->SetLocalContent(content1.get(), SdpType::kOffer, err));
    EXPECT_TRUE(media_send_channel1_impl()->HasSendStream(1));

    // Receive PR answer
    std::unique_ptr<typename T::Content> content2(
        CreateMediaContentWithStream(2));
    EXPECT_TRUE(
        channel1_->SetRemoteContent(content2.get(), SdpType::kPrAnswer, err));
    EXPECT_TRUE(media_send_channel1_impl()->HasSendStream(1));
    EXPECT_TRUE(media_receive_channel1_impl()->HasRecvStream(2));

    // Receive answer
    std::unique_ptr<typename T::Content> content3(
        CreateMediaContentWithStream(3));
    EXPECT_TRUE(
        channel1_->SetRemoteContent(content3.get(), SdpType::kAnswer, err));
    EXPECT_TRUE(media_send_channel1_impl()->HasSendStream(1));
    EXPECT_FALSE(media_receive_channel1_impl()->HasRecvStream(2));
    EXPECT_TRUE(media_receive_channel1_impl()->HasRecvStream(3));
  }

  void TestOnTransportReadyToSend() {
    CreateChannels(0, 0);
    EXPECT_FALSE(media_send_channel1_impl()->ready_to_send());

    network_thread_->PostTask(
        [this] { channel1_->OnTransportReadyToSend(true); });
    WaitForThreads();
    EXPECT_TRUE(media_send_channel1_impl()->ready_to_send());

    network_thread_->PostTask(
        [this] { channel1_->OnTransportReadyToSend(false); });
    WaitForThreads();
    EXPECT_FALSE(media_send_channel1_impl()->ready_to_send());
  }

  bool SetRemoteContentWithBitrateLimit(int remote_limit) {
    typename T::Content content;
    CreateContent(0, kPcmuCodec, kH264Codec, &content);
    content.set_bandwidth(remote_limit);
    return channel1_->SetRemoteContent(&content, SdpType::kOffer, NULL);
  }

  webrtc::RtpParameters BitrateLimitedParameters(std::optional<int> limit) {
    webrtc::RtpParameters parameters;
    webrtc::RtpEncodingParameters encoding;
    encoding.max_bitrate_bps = limit;
    parameters.encodings.push_back(encoding);
    return parameters;
  }

  void VerifyMaxBitrate(const webrtc::RtpParameters& parameters,
                        std::optional<int> expected_bitrate) {
    EXPECT_EQ(1UL, parameters.encodings.size());
    EXPECT_EQ(expected_bitrate, parameters.encodings[0].max_bitrate_bps);
  }

  void DefaultMaxBitrateIsUnlimited() {
    CreateChannels(0, 0);
    std::string err;
    EXPECT_TRUE(channel1_->SetLocalContent(&local_media_content1_,
                                           SdpType::kOffer, err));
    EXPECT_EQ(media_send_channel1_impl()->max_bps(), -1);
    VerifyMaxBitrate(media_send_channel1()->GetRtpSendParameters(kSsrc1),
                     std::nullopt);
  }

  // Test that when a channel gets new RtpTransport with a call to
  // `SetRtpTransport`, the socket options from the old RtpTransport is merged
  // with the options on the new one.

  // For example, audio and video may use separate socket options, but initially
  // be unbundled, then later become bundled. When this happens, their preferred
  // socket options should be merged to the underlying transport they share.
  void SocketOptionsMergedOnSetTransport() {
    constexpr int kSndBufSize = 4000;
    constexpr int kRcvBufSize = 8000;

    CreateChannels(DTLS, DTLS);

    bool rcv_success, send_success;
    int rcv_buf, send_buf;
    SendTask(network_thread_, [&] {
      new_rtp_transport_ = CreateDtlsSrtpTransport(
          fake_rtp_dtls_transport2_.get(), fake_rtcp_dtls_transport2_.get());
      channel1_->SetOption(cricket::BaseChannel::ST_RTP,
                           rtc::Socket::Option::OPT_SNDBUF, kSndBufSize);
      channel2_->SetOption(cricket::BaseChannel::ST_RTP,
                           rtc::Socket::Option::OPT_RCVBUF, kRcvBufSize);
      channel1_->SetRtpTransport(new_rtp_transport_.get());
      send_success = fake_rtp_dtls_transport2_->GetOption(
          rtc::Socket::Option::OPT_SNDBUF, &send_buf);
      rcv_success = fake_rtp_dtls_transport2_->GetOption(
          rtc::Socket::Option::OPT_RCVBUF, &rcv_buf);
    });

    ASSERT_TRUE(send_success);
    EXPECT_EQ(kSndBufSize, send_buf);
    ASSERT_TRUE(rcv_success);
    EXPECT_EQ(kRcvBufSize, rcv_buf);
  }

  void CreateSimulcastContent(const std::vector<std::string>& rids,
                              typename T::Content* content) {
    std::vector<RidDescription> rid_descriptions;
    for (const std::string& name : rids) {
      rid_descriptions.push_back(RidDescription(name, RidDirection::kSend));
    }

    StreamParams stream;
    stream.set_rids(rid_descriptions);
    CreateContent(0, kPcmuCodec, kH264Codec, content);
    // This is for unified plan, so there can be only one StreamParams.
    content->mutable_streams().clear();
    content->AddStream(stream);
  }

  void VerifySimulcastStreamParams(const StreamParams& expected,
                                   const typename T::Channel* channel) {
    const std::vector<StreamParams>& streams = channel->local_streams();
    ASSERT_EQ(1u, streams.size());
    const StreamParams& result = streams[0];
    EXPECT_EQ(expected.rids(), result.rids());
    EXPECT_TRUE(result.has_ssrcs());
    EXPECT_EQ(expected.rids().size() * 2, result.ssrcs.size());
    std::vector<uint32_t> primary_ssrcs;
    result.GetPrimarySsrcs(&primary_ssrcs);
    EXPECT_EQ(expected.rids().size(), primary_ssrcs.size());
  }

  void TestUpdateLocalStreamsWithSimulcast() {
    CreateChannels(0, 0);
    typename T::Content content1, content2, content3;
    CreateSimulcastContent({"f", "h", "q"}, &content1);
    std::string err;
    EXPECT_TRUE(channel1_->SetLocalContent(&content1, SdpType::kOffer, err));
    VerifySimulcastStreamParams(content1.streams()[0], channel1_.get());
    StreamParams stream1 = channel1_->local_streams()[0];

    // Create a similar offer. SetLocalContent should not remove and add.
    CreateSimulcastContent({"f", "h", "q"}, &content2);
    EXPECT_TRUE(channel1_->SetLocalContent(&content2, SdpType::kOffer, err));
    VerifySimulcastStreamParams(content2.streams()[0], channel1_.get());
    StreamParams stream2 = channel1_->local_streams()[0];
    // Check that the streams are identical (SSRCs didn't change).
    EXPECT_EQ(stream1, stream2);

    // Create third offer that has same RIDs in different order.
    CreateSimulcastContent({"f", "q", "h"}, &content3);
    EXPECT_TRUE(channel1_->SetLocalContent(&content3, SdpType::kOffer, err));
    VerifySimulcastStreamParams(content3.streams()[0], channel1_.get());
  }

 protected:
  void WaitForThreads() { WaitForThreads(rtc::ArrayView<rtc::Thread*>()); }
  static void ProcessThreadQueue(rtc::Thread* thread) {
    RTC_DCHECK(thread->IsCurrent());
    while (!thread->empty()) {
      thread->ProcessMessages(0);
    }
  }
  static void FlushCurrentThread() {
    rtc::Thread::Current()->ProcessMessages(0);
  }
  void WaitForThreads(rtc::ArrayView<rtc::Thread*> threads) {
    // `threads` and current thread post packets to network thread.
    for (rtc::Thread* thread : threads) {
      SendTask(thread, [thread] { ProcessThreadQueue(thread); });
    }
    ProcessThreadQueue(rtc::Thread::Current());
    // Network thread move them around and post back to worker = current thread.
    if (!network_thread_->IsCurrent()) {
      SendTask(network_thread_,
               [this] { ProcessThreadQueue(network_thread_); });
    }
    // Worker thread = current Thread process received messages.
    ProcessThreadQueue(rtc::Thread::Current());
  }

  // Accessors that return the standard VideoMedia{Send|Receive}ChannelInterface
  typename T::MediaSendChannelInterface* media_send_channel1() {
    return channel1_->media_send_channel();
  }
  typename T::MediaSendChannelInterface* media_send_channel2() {
    return channel2_->media_send_channel();
  }
  typename T::MediaReceiveChannelInterface* media_receive_channel1() {
    return channel1_->media_receive_channel();
  }
  typename T::MediaReceiveChannelInterface* media_receive_channel2() {
    return channel2_->media_receive_channel();
  }

  // Accessors that return the FakeMedia<type>SendChannel object.
  // Note that these depend on getting the object back that was
  // passed to the channel constructor.
  // T::MediaSendChannel is either FakeVoiceMediaSendChannel or
  // FakeVideoMediaSendChannel.
  typename T::MediaSendChannel* media_send_channel1_impl() {
    RTC_DCHECK(channel1_);
    return static_cast<typename T::MediaSendChannel*>(
        channel1_->media_send_channel());
  }

  typename T::MediaSendChannel* media_send_channel2_impl() {
    RTC_DCHECK(channel2_);
    RTC_DCHECK(channel2_->media_send_channel());
    return static_cast<typename T::MediaSendChannel*>(
        channel2_->media_send_channel());
  }
  typename T::MediaReceiveChannel* media_receive_channel1_impl() {
    RTC_DCHECK(channel1_);
    RTC_DCHECK(channel1_->media_receive_channel());
    return static_cast<typename T::MediaReceiveChannel*>(
        channel1_->media_receive_channel());
  }

  typename T::MediaReceiveChannel* media_receive_channel2_impl() {
    RTC_DCHECK(channel2_);
    RTC_DCHECK(channel2_->media_receive_channel());
    return static_cast<typename T::MediaReceiveChannel*>(
        channel2_->media_receive_channel());
  }

  rtc::AutoThread main_thread_;
  // TODO(pbos): Remove playout from all media channels and let renderers mute
  // themselves.
  const bool verify_playout_;
  rtc::scoped_refptr<webrtc::PendingTaskSafetyFlag> network_thread_safety_ =
      webrtc::PendingTaskSafetyFlag::CreateDetached();
  std::unique_ptr<rtc::Thread> network_thread_keeper_;
  rtc::Thread* network_thread_;
  std::unique_ptr<cricket::FakeDtlsTransport> fake_rtp_dtls_transport1_;
  std::unique_ptr<cricket::FakeDtlsTransport> fake_rtcp_dtls_transport1_;
  std::unique_ptr<cricket::FakeDtlsTransport> fake_rtp_dtls_transport2_;
  std::unique_ptr<cricket::FakeDtlsTransport> fake_rtcp_dtls_transport2_;
  std::unique_ptr<rtc::FakePacketTransport> fake_rtp_packet_transport1_;
  std::unique_ptr<rtc::FakePacketTransport> fake_rtcp_packet_transport1_;
  std::unique_ptr<rtc::FakePacketTransport> fake_rtp_packet_transport2_;
  std::unique_ptr<rtc::FakePacketTransport> fake_rtcp_packet_transport2_;
  std::unique_ptr<webrtc::RtpTransportInternal> rtp_transport1_;
  std::unique_ptr<webrtc::RtpTransportInternal> rtp_transport2_;
  std::unique_ptr<webrtc::RtpTransportInternal> new_rtp_transport_;
  cricket::FakeMediaEngine media_engine_;
  std::unique_ptr<typename T::Channel> channel1_;
  std::unique_ptr<typename T::Channel> channel2_;
  typename T::Content local_media_content1_;
  typename T::Content local_media_content2_;
  typename T::Content remote_media_content1_;
  typename T::Content remote_media_content2_;
  // The RTP and RTCP packets to send in the tests.
  rtc::Buffer rtp_packet_;
  rtc::Buffer rtcp_packet_;
  cricket::CandidatePairInterface* last_selected_candidate_pair_;
  rtc::UniqueRandomIdGenerator ssrc_generator_;
  webrtc::test::ScopedKeyValueConfig field_trials_;
};

template <>
std::unique_ptr<cricket::VoiceChannel> ChannelTest<VoiceTraits>::CreateChannel(
    rtc::Thread* worker_thread,
    rtc::Thread* network_thread,
    std::unique_ptr<cricket::FakeVoiceMediaSendChannel> send_ch,
    std::unique_ptr<cricket::FakeVoiceMediaReceiveChannel> receive_ch,
    webrtc::RtpTransportInternal* rtp_transport,
    int flags) {
  rtc::Thread* signaling_thread = rtc::Thread::Current();
  auto channel = std::make_unique<cricket::VoiceChannel>(
      worker_thread, network_thread, signaling_thread, std::move(send_ch),
      std::move(receive_ch), cricket::CN_AUDIO, (flags & DTLS) != 0,
      webrtc::CryptoOptions(), &ssrc_generator_);
  SendTask(network_thread, [&]() {
    RTC_DCHECK_RUN_ON(channel->network_thread());
    channel->SetRtpTransport(rtp_transport);
  });
  return channel;
}

template <>
void ChannelTest<VoiceTraits>::CreateContent(
    int flags,
    const cricket::Codec& audio_codec,
    const cricket::Codec& video_codec,
    cricket::AudioContentDescription* audio) {
  audio->AddCodec(audio_codec);
  audio->set_rtcp_mux((flags & RTCP_MUX) != 0);
}

template <>
void ChannelTest<VoiceTraits>::CopyContent(
    const cricket::AudioContentDescription& source,
    cricket::AudioContentDescription* audio) {
  *audio = source;
}

template <>
void ChannelTest<VoiceTraits>::AddLegacyStreamInContent(
    uint32_t ssrc,
    int flags,
    cricket::AudioContentDescription* audio) {
  audio->AddLegacyStream(ssrc);
}

class VoiceChannelSingleThreadTest : public ChannelTest<VoiceTraits> {
 public:
  typedef ChannelTest<VoiceTraits> Base;
  VoiceChannelSingleThreadTest()
      : Base(true, kPcmuFrame, kRtcpReport, NetworkIsWorker::Yes) {}
};

class VoiceChannelDoubleThreadTest : public ChannelTest<VoiceTraits> {
 public:
  typedef ChannelTest<VoiceTraits> Base;
  VoiceChannelDoubleThreadTest()
      : Base(true, kPcmuFrame, kRtcpReport, NetworkIsWorker::No) {}
};

class VoiceChannelWithEncryptedRtpHeaderExtensionsSingleThreadTest
    : public ChannelTest<VoiceTraits> {
 public:
  typedef ChannelTest<VoiceTraits> Base;
  VoiceChannelWithEncryptedRtpHeaderExtensionsSingleThreadTest()
      : Base(true,
             kPcmuFrameWithExtensions,
             kRtcpReport,
             NetworkIsWorker::Yes) {}
};

class VoiceChannelWithEncryptedRtpHeaderExtensionsDoubleThreadTest
    : public ChannelTest<VoiceTraits> {
 public:
  typedef ChannelTest<VoiceTraits> Base;
  VoiceChannelWithEncryptedRtpHeaderExtensionsDoubleThreadTest()
      : Base(true, kPcmuFrameWithExtensions, kRtcpReport, NetworkIsWorker::No) {
  }
};

// override to add NULL parameter
template <>
std::unique_ptr<cricket::VideoChannel> ChannelTest<VideoTraits>::CreateChannel(
    rtc::Thread* worker_thread,
    rtc::Thread* network_thread,
    std::unique_ptr<cricket::FakeVideoMediaSendChannel> send_ch,
    std::unique_ptr<cricket::FakeVideoMediaReceiveChannel> receive_ch,
    webrtc::RtpTransportInternal* rtp_transport,
    int flags) {
  rtc::Thread* signaling_thread = rtc::Thread::Current();
  auto channel = std::make_unique<cricket::VideoChannel>(
      worker_thread, network_thread, signaling_thread, std::move(send_ch),
      std::move(receive_ch), cricket::CN_VIDEO, (flags & DTLS) != 0,
      webrtc::CryptoOptions(), &ssrc_generator_);
  SendTask(network_thread, [&]() {
    RTC_DCHECK_RUN_ON(channel->network_thread());
    channel->SetRtpTransport(rtp_transport);
  });
  return channel;
}

template <>
void ChannelTest<VideoTraits>::CreateContent(
    int flags,
    const cricket::Codec& audio_codec,
    const cricket::Codec& video_codec,
    cricket::VideoContentDescription* video) {
  video->AddCodec(video_codec);
  video->set_rtcp_mux((flags & RTCP_MUX) != 0);
}

template <>
void ChannelTest<VideoTraits>::CopyContent(
    const cricket::VideoContentDescription& source,
    cricket::VideoContentDescription* video) {
  *video = source;
}

template <>
void ChannelTest<VideoTraits>::AddLegacyStreamInContent(
    uint32_t ssrc,
    int flags,
    cricket::VideoContentDescription* video) {
  video->AddLegacyStream(ssrc);
}

class VideoChannelSingleThreadTest : public ChannelTest<VideoTraits> {
 public:
  typedef ChannelTest<VideoTraits> Base;
  VideoChannelSingleThreadTest()
      : Base(false, kH264Packet, kRtcpReport, NetworkIsWorker::Yes) {}
};

class VideoChannelDoubleThreadTest : public ChannelTest<VideoTraits> {
 public:
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