Add thread annotations to FakeIceTransport

Bug: webrtc:12339
Change-Id: I29f5c910c60155cbb48c686e77b02ad3aa761fb1
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/211665
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33500}
diff --git a/p2p/base/fake_dtls_transport.h b/p2p/base/fake_dtls_transport.h
index f17eddf..daec158 100644
--- a/p2p/base/fake_dtls_transport.h
+++ b/p2p/base/fake_dtls_transport.h
@@ -55,9 +55,15 @@
 
   // If this constructor is called, a new fake ICE transport will be created,
   // and this FakeDtlsTransport will take the ownership.
-  explicit FakeDtlsTransport(const std::string& name, int component)
+  FakeDtlsTransport(const std::string& name, int component)
       : FakeDtlsTransport(std::make_unique<FakeIceTransport>(name, component)) {
   }
+  FakeDtlsTransport(const std::string& name,
+                    int component,
+                    rtc::Thread* network_thread)
+      : FakeDtlsTransport(std::make_unique<FakeIceTransport>(name,
+                                                             component,
+                                                             network_thread)) {}
 
   ~FakeDtlsTransport() override {
     if (dest_ && dest_->dest_ == this) {
diff --git a/p2p/base/fake_ice_transport.h b/p2p/base/fake_ice_transport.h
index f39da7c..58d83d7 100644
--- a/p2p/base/fake_ice_transport.h
+++ b/p2p/base/fake_ice_transport.h
@@ -25,6 +25,9 @@
 
 namespace cricket {
 
+// All methods must be called on the network thread (which is either the thread
+// calling the constructor, or the separate thread explicitly passed to the
+// constructor).
 class FakeIceTransport : public IceTransportInternal {
  public:
   explicit FakeIceTransport(const std::string& name,
@@ -34,6 +37,8 @@
         component_(component),
         network_thread_(network_thread ? network_thread
                                        : rtc::Thread::Current()) {}
+  // Must be called either on the network thread, or after the network thread
+  // has been shut down.
   ~FakeIceTransport() override {
     if (dest_ && dest_->dest_ == this) {
       dest_->dest_ = nullptr;
@@ -42,18 +47,31 @@
 
   // If async, will send packets by "Post"-ing to message queue instead of
   // synchronously "Send"-ing.
-  void SetAsync(bool async) { async_ = async; }
-  void SetAsyncDelay(int delay_ms) { async_delay_ms_ = delay_ms; }
+  void SetAsync(bool async) {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    async_ = async;
+  }
+  void SetAsyncDelay(int delay_ms) {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    async_delay_ms_ = delay_ms;
+  }
 
   // SetWritable, SetReceiving and SetDestination are the main methods that can
   // be used for testing, to simulate connectivity or lack thereof.
-  void SetWritable(bool writable) { set_writable(writable); }
-  void SetReceiving(bool receiving) { set_receiving(receiving); }
+  void SetWritable(bool writable) {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    set_writable(writable);
+  }
+  void SetReceiving(bool receiving) {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    set_receiving(receiving);
+  }
 
   // Simulates the two transports connecting to each other.
   // If |asymmetric| is true this method only affects this FakeIceTransport.
   // If false, it affects |dest| as well.
   void SetDestination(FakeIceTransport* dest, bool asymmetric = false) {
+    RTC_DCHECK_RUN_ON(network_thread_);
     if (dest == dest_) {
       return;
     }
@@ -75,12 +93,14 @@
 
   void SetTransportState(webrtc::IceTransportState state,
                          IceTransportState legacy_state) {
+    RTC_DCHECK_RUN_ON(network_thread_);
     transport_state_ = state;
     legacy_transport_state_ = legacy_state;
     SignalIceTransportStateChanged(this);
   }
 
   void SetConnectionCount(size_t connection_count) {
+    RTC_DCHECK_RUN_ON(network_thread_);
     size_t old_connection_count = connection_count_;
     connection_count_ = connection_count;
     if (connection_count) {
@@ -94,6 +114,7 @@
   }
 
   void SetCandidatesGatheringComplete() {
+    RTC_DCHECK_RUN_ON(network_thread_);
     if (gathering_state_ != kIceGatheringComplete) {
       gathering_state_ = kIceGatheringComplete;
       SignalGatheringState(this);
@@ -102,16 +123,29 @@
 
   // Convenience functions for accessing ICE config and other things.
   int receiving_timeout() const {
+    RTC_DCHECK_RUN_ON(network_thread_);
     return ice_config_.receiving_timeout_or_default();
   }
-  bool gather_continually() const { return ice_config_.gather_continually(); }
-  const Candidates& remote_candidates() const { return remote_candidates_; }
+  bool gather_continually() const {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    return ice_config_.gather_continually();
+  }
+  const Candidates& remote_candidates() const {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    return remote_candidates_;
+  }
 
   // Fake IceTransportInternal implementation.
   const std::string& transport_name() const override { return name_; }
   int component() const override { return component_; }
-  uint64_t IceTiebreaker() const { return tiebreaker_; }
-  IceMode remote_ice_mode() const { return remote_ice_mode_; }
+  uint64_t IceTiebreaker() const {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    return tiebreaker_;
+  }
+  IceMode remote_ice_mode() const {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    return remote_ice_mode_;
+  }
   const std::string& ice_ufrag() const { return ice_parameters_.ufrag; }
   const std::string& ice_pwd() const { return ice_parameters_.pwd; }
   const std::string& remote_ice_ufrag() const {
@@ -126,6 +160,7 @@
   }
 
   IceTransportState GetState() const override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     if (legacy_transport_state_) {
       return *legacy_transport_state_;
     }
@@ -143,6 +178,7 @@
   }
 
   webrtc::IceTransportState GetIceTransportState() const override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     if (transport_state_) {
       return *transport_state_;
     }
@@ -159,21 +195,34 @@
     return webrtc::IceTransportState::kConnected;
   }
 
-  void SetIceRole(IceRole role) override { role_ = role; }
-  IceRole GetIceRole() const override { return role_; }
+  void SetIceRole(IceRole role) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    role_ = role;
+  }
+  IceRole GetIceRole() const override {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    return role_;
+  }
   void SetIceTiebreaker(uint64_t tiebreaker) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     tiebreaker_ = tiebreaker;
   }
   void SetIceParameters(const IceParameters& ice_params) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     ice_parameters_ = ice_params;
   }
   void SetRemoteIceParameters(const IceParameters& params) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     remote_ice_parameters_ = params;
   }
 
-  void SetRemoteIceMode(IceMode mode) override { remote_ice_mode_ = mode; }
+  void SetRemoteIceMode(IceMode mode) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    remote_ice_mode_ = mode;
+  }
 
   void MaybeStartGathering() override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     if (gathering_state_ == kIceGatheringNew) {
       gathering_state_ = kIceGatheringGathering;
       SignalGatheringState(this);
@@ -181,15 +230,21 @@
   }
 
   IceGatheringState gathering_state() const override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     return gathering_state_;
   }
 
-  void SetIceConfig(const IceConfig& config) override { ice_config_ = config; }
+  void SetIceConfig(const IceConfig& config) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    ice_config_ = config;
+  }
 
   void AddRemoteCandidate(const Candidate& candidate) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     remote_candidates_.push_back(candidate);
   }
   void RemoveRemoteCandidate(const Candidate& candidate) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     auto it = absl::c_find(remote_candidates_, candidate);
     if (it == remote_candidates_.end()) {
       RTC_LOG(LS_INFO) << "Trying to remove a candidate which doesn't exist.";
@@ -199,7 +254,10 @@
     remote_candidates_.erase(it);
   }
 
-  void RemoveAllRemoteCandidates() override { remote_candidates_.clear(); }
+  void RemoveAllRemoteCandidates() override {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    remote_candidates_.clear();
+  }
 
   bool GetStats(IceTransportStats* ice_transport_stats) override {
     CandidateStats candidate_stats;
@@ -220,17 +278,25 @@
   }
 
   // Fake PacketTransportInternal implementation.
-  bool writable() const override { return writable_; }
-  bool receiving() const override { return receiving_; }
+  bool writable() const override {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    return writable_;
+  }
+  bool receiving() const override {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    return receiving_;
+  }
   // If combine is enabled, every two consecutive packets to be sent with
   // "SendPacket" will be combined into one outgoing packet.
   void combine_outgoing_packets(bool combine) {
+    RTC_DCHECK_RUN_ON(network_thread_);
     combine_outgoing_packets_ = combine;
   }
   int SendPacket(const char* data,
                  size_t len,
                  const rtc::PacketOptions& options,
                  int flags) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     if (!dest_) {
       return -1;
     }
@@ -240,8 +306,11 @@
       rtc::CopyOnWriteBuffer packet(std::move(send_packet_));
       if (async_) {
         invoker_.AsyncInvokeDelayed<void>(
-            RTC_FROM_HERE, rtc::Thread::Current(),
-            [this, packet] { FakeIceTransport::SendPacketInternal(packet); },
+            RTC_FROM_HERE, network_thread_,
+            [this, packet] {
+              RTC_DCHECK_RUN_ON(network_thread_);
+              FakeIceTransport::SendPacketInternal(packet);
+            },
             async_delay_ms_);
       } else {
         SendPacketInternal(packet);
@@ -253,10 +322,12 @@
   }
 
   int SetOption(rtc::Socket::Option opt, int value) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     socket_options_[opt] = value;
     return true;
   }
   bool GetOption(rtc::Socket::Option opt, int* value) override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     auto it = socket_options_.find(opt);
     if (it != socket_options_.end()) {
       *value = it->second;
@@ -268,19 +339,27 @@
 
   int GetError() override { return 0; }
 
-  rtc::CopyOnWriteBuffer last_sent_packet() { return last_sent_packet_; }
+  rtc::CopyOnWriteBuffer last_sent_packet() {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    return last_sent_packet_;
+  }
 
   absl::optional<rtc::NetworkRoute> network_route() const override {
+    RTC_DCHECK_RUN_ON(network_thread_);
     return network_route_;
   }
   void SetNetworkRoute(absl::optional<rtc::NetworkRoute> network_route) {
+    RTC_DCHECK_RUN_ON(network_thread_);
     network_route_ = network_route;
-    network_thread_->Invoke<void>(
-        RTC_FROM_HERE, [this] { SignalNetworkRouteChanged(network_route_); });
+    network_thread_->Invoke<void>(RTC_FROM_HERE, [this] {
+      RTC_DCHECK_RUN_ON(network_thread_);
+      SignalNetworkRouteChanged(network_route_);
+    });
   }
 
  private:
-  void set_writable(bool writable) {
+  void set_writable(bool writable)
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(network_thread_) {
     if (writable_ == writable) {
       return;
     }
@@ -292,7 +371,8 @@
     SignalWritableState(this);
   }
 
-  void set_receiving(bool receiving) {
+  void set_receiving(bool receiving)
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(network_thread_) {
     if (receiving_ == receiving) {
       return;
     }
@@ -300,7 +380,8 @@
     SignalReceivingState(this);
   }
 
-  void SendPacketInternal(const rtc::CopyOnWriteBuffer& packet) {
+  void SendPacketInternal(const rtc::CopyOnWriteBuffer& packet)
+      RTC_EXCLUSIVE_LOCKS_REQUIRED(network_thread_) {
     if (dest_) {
       last_sent_packet_ = packet;
       dest_->SignalReadPacket(dest_, packet.data<char>(), packet.size(),
@@ -309,30 +390,35 @@
   }
 
   rtc::AsyncInvoker invoker_;
-  std::string name_;
-  int component_;
-  FakeIceTransport* dest_ = nullptr;
-  bool async_ = false;
-  int async_delay_ms_ = 0;
-  Candidates remote_candidates_;
-  IceConfig ice_config_;
-  IceRole role_ = ICEROLE_UNKNOWN;
-  uint64_t tiebreaker_ = 0;
-  IceParameters ice_parameters_;
-  IceParameters remote_ice_parameters_;
-  IceMode remote_ice_mode_ = ICEMODE_FULL;
-  size_t connection_count_ = 0;
-  absl::optional<webrtc::IceTransportState> transport_state_;
-  absl::optional<IceTransportState> legacy_transport_state_;
-  IceGatheringState gathering_state_ = kIceGatheringNew;
-  bool had_connection_ = false;
-  bool writable_ = false;
-  bool receiving_ = false;
-  bool combine_outgoing_packets_ = false;
-  rtc::CopyOnWriteBuffer send_packet_;
-  absl::optional<rtc::NetworkRoute> network_route_;
-  std::map<rtc::Socket::Option, int> socket_options_;
-  rtc::CopyOnWriteBuffer last_sent_packet_;
+  const std::string name_;
+  const int component_;
+  FakeIceTransport* dest_ RTC_GUARDED_BY(network_thread_) = nullptr;
+  bool async_ RTC_GUARDED_BY(network_thread_) = false;
+  int async_delay_ms_ RTC_GUARDED_BY(network_thread_) = 0;
+  Candidates remote_candidates_ RTC_GUARDED_BY(network_thread_);
+  IceConfig ice_config_ RTC_GUARDED_BY(network_thread_);
+  IceRole role_ RTC_GUARDED_BY(network_thread_) = ICEROLE_UNKNOWN;
+  uint64_t tiebreaker_ RTC_GUARDED_BY(network_thread_) = 0;
+  IceParameters ice_parameters_ RTC_GUARDED_BY(network_thread_);
+  IceParameters remote_ice_parameters_ RTC_GUARDED_BY(network_thread_);
+  IceMode remote_ice_mode_ RTC_GUARDED_BY(network_thread_) = ICEMODE_FULL;
+  size_t connection_count_ RTC_GUARDED_BY(network_thread_) = 0;
+  absl::optional<webrtc::IceTransportState> transport_state_
+      RTC_GUARDED_BY(network_thread_);
+  absl::optional<IceTransportState> legacy_transport_state_
+      RTC_GUARDED_BY(network_thread_);
+  IceGatheringState gathering_state_ RTC_GUARDED_BY(network_thread_) =
+      kIceGatheringNew;
+  bool had_connection_ RTC_GUARDED_BY(network_thread_) = false;
+  bool writable_ RTC_GUARDED_BY(network_thread_) = false;
+  bool receiving_ RTC_GUARDED_BY(network_thread_) = false;
+  bool combine_outgoing_packets_ RTC_GUARDED_BY(network_thread_) = false;
+  rtc::CopyOnWriteBuffer send_packet_ RTC_GUARDED_BY(network_thread_);
+  absl::optional<rtc::NetworkRoute> network_route_
+      RTC_GUARDED_BY(network_thread_);
+  std::map<rtc::Socket::Option, int> socket_options_
+      RTC_GUARDED_BY(network_thread_);
+  rtc::CopyOnWriteBuffer last_sent_packet_ RTC_GUARDED_BY(network_thread_);
   rtc::Thread* const network_thread_;
 };
 
diff --git a/pc/channel_manager_unittest.cc b/pc/channel_manager_unittest.cc
index 610d797..c0dddd8 100644
--- a/pc/channel_manager_unittest.cc
+++ b/pc/channel_manager_unittest.cc
@@ -62,16 +62,6 @@
     fme_->SetVideoCodecs(MAKE_VECTOR(kVideoCodecs));
   }
 
-  std::unique_ptr<webrtc::RtpTransportInternal> CreateDtlsSrtpTransport() {
-    rtp_dtls_transport_ = std::make_unique<FakeDtlsTransport>(
-        "fake_dtls_transport", cricket::ICE_CANDIDATE_COMPONENT_RTP);
-    auto dtls_srtp_transport = std::make_unique<webrtc::DtlsSrtpTransport>(
-        /*rtcp_mux_required=*/true);
-    dtls_srtp_transport->SetDtlsTransports(rtp_dtls_transport_.get(),
-                                           /*rtcp_dtls_transport=*/nullptr);
-    return dtls_srtp_transport;
-  }
-
   void TestCreateDestroyChannels(webrtc::RtpTransportInternal* rtp_transport) {
     cricket::VoiceChannel* voice_channel = cm_->CreateVoiceChannel(
         &fake_call_, cricket::MediaConfig(), rtp_transport,
@@ -95,7 +85,6 @@
     cm_->Terminate();
   }
 
-  std::unique_ptr<DtlsTransportInternal> rtp_dtls_transport_;
   std::unique_ptr<rtc::Thread> network_;
   std::unique_ptr<rtc::Thread> worker_;
   std::unique_ptr<webrtc::VideoBitrateAllocatorFactory>
@@ -178,8 +167,13 @@
 
 TEST_F(ChannelManagerTest, CreateDestroyChannels) {
   EXPECT_TRUE(cm_->Init());
-  auto rtp_transport = CreateDtlsSrtpTransport();
-  TestCreateDestroyChannels(rtp_transport.get());
+  auto rtp_dtls_transport = std::make_unique<FakeDtlsTransport>(
+      "fake_dtls_transport", cricket::ICE_CANDIDATE_COMPONENT_RTP);
+  auto dtls_srtp_transport = std::make_unique<webrtc::DtlsSrtpTransport>(
+      /*rtcp_mux_required=*/true);
+  dtls_srtp_transport->SetDtlsTransports(rtp_dtls_transport.get(),
+                                         /*rtcp_dtls_transport=*/nullptr);
+  TestCreateDestroyChannels(dtls_srtp_transport.get());
 }
 
 TEST_F(ChannelManagerTest, CreateDestroyChannelsOnThread) {
@@ -188,8 +182,17 @@
   EXPECT_TRUE(cm_->set_worker_thread(worker_.get()));
   EXPECT_TRUE(cm_->set_network_thread(network_.get()));
   EXPECT_TRUE(cm_->Init());
-  auto rtp_transport = CreateDtlsSrtpTransport();
-  TestCreateDestroyChannels(rtp_transport.get());
+  auto rtp_dtls_transport = std::make_unique<FakeDtlsTransport>(
+      "fake_dtls_transport", cricket::ICE_CANDIDATE_COMPONENT_RTP,
+      network_.get());
+  auto dtls_srtp_transport = std::make_unique<webrtc::DtlsSrtpTransport>(
+      /*rtcp_mux_required=*/true);
+  network_->Invoke<void>(
+      RTC_FROM_HERE, [&rtp_dtls_transport, &dtls_srtp_transport] {
+        dtls_srtp_transport->SetDtlsTransports(rtp_dtls_transport.get(),
+                                               /*rtcp_dtls_transport=*/nullptr);
+      });
+  TestCreateDestroyChannels(dtls_srtp_transport.get());
 }
 
 }  // namespace cricket
diff --git a/pc/channel_unittest.cc b/pc/channel_unittest.cc
index 4a0a6b4..ea4e828 100644
--- a/pc/channel_unittest.cc
+++ b/pc/channel_unittest.cc
@@ -170,11 +170,12 @@
     } else {
       // Confirmed to work with KT_RSA and KT_ECDSA.
       fake_rtp_dtls_transport1_.reset(new cricket::FakeDtlsTransport(
-          "channel1", cricket::ICE_CANDIDATE_COMPONENT_RTP));
+          "channel1", cricket::ICE_CANDIDATE_COMPONENT_RTP, network_thread_));
       rtp1 = fake_rtp_dtls_transport1_.get();
       if (!(flags1 & RTCP_MUX)) {
         fake_rtcp_dtls_transport1_.reset(new cricket::FakeDtlsTransport(
-            "channel1", cricket::ICE_CANDIDATE_COMPONENT_RTCP));
+            "channel1", cricket::ICE_CANDIDATE_COMPONENT_RTCP,
+            network_thread_));
         rtcp1 = fake_rtcp_dtls_transport1_.get();
       }
       if (flags1 & DTLS) {
@@ -199,11 +200,12 @@
     } else {
       // Confirmed to work with KT_RSA and KT_ECDSA.
       fake_rtp_dtls_transport2_.reset(new cricket::FakeDtlsTransport(
-          "channel2", cricket::ICE_CANDIDATE_COMPONENT_RTP));
+          "channel2", cricket::ICE_CANDIDATE_COMPONENT_RTP, network_thread_));
       rtp2 = fake_rtp_dtls_transport2_.get();
       if (!(flags2 & RTCP_MUX)) {
         fake_rtcp_dtls_transport2_.reset(new cricket::FakeDtlsTransport(
-            "channel2", cricket::ICE_CANDIDATE_COMPONENT_RTCP));
+            "channel2", cricket::ICE_CANDIDATE_COMPONENT_RTCP,
+            network_thread_));
         rtcp2 = fake_rtcp_dtls_transport2_.get();
       }
       if (flags2 & DTLS) {
@@ -284,10 +286,14 @@
     auto rtp_transport = std::make_unique<webrtc::RtpTransport>(
         rtcp_packet_transport == nullptr);
 
-    rtp_transport->SetRtpPacketTransport(rtp_packet_transport);
-    if (rtcp_packet_transport) {
-      rtp_transport->SetRtcpPacketTransport(rtcp_packet_transport);
-    }
+    network_thread_->Invoke<void>(
+        RTC_FROM_HERE,
+        [&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;
   }
 
@@ -297,8 +303,12 @@
     auto dtls_srtp_transport = std::make_unique<webrtc::DtlsSrtpTransport>(
         rtcp_dtls_transport == nullptr);
 
-    dtls_srtp_transport->SetDtlsTransports(rtp_dtls_transport,
-                                           rtcp_dtls_transport);
+    network_thread_->Invoke<void>(
+        RTC_FROM_HERE,
+        [&dtls_srtp_transport, rtp_dtls_transport, rtcp_dtls_transport] {
+          dtls_srtp_transport->SetDtlsTransports(rtp_dtls_transport,
+                                                 rtcp_dtls_transport);
+        });
     return dtls_srtp_transport;
   }
 
@@ -1268,13 +1278,19 @@
         fake_rtp_dtls_transport2_.get(), fake_rtcp_dtls_transport2_.get());
     channel1_->SetRtpTransport(new_rtp_transport_.get());
 
-    int option_val;
-    ASSERT_TRUE(fake_rtp_dtls_transport2_->GetOption(
-        rtc::Socket::Option::OPT_SNDBUF, &option_val));
-    EXPECT_EQ(kSndBufSize, option_val);
-    ASSERT_TRUE(fake_rtp_dtls_transport2_->GetOption(
-        rtc::Socket::Option::OPT_RCVBUF, &option_val));
-    EXPECT_EQ(kRcvBufSize, option_val);
+    bool rcv_success, send_success;
+    int rcv_buf, send_buf;
+    network_thread_->Invoke<void>(RTC_FROM_HERE, [&] {
+      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,