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chromium/net/socket/udp_socket_unittest.cc 

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/socket/udp_socket.h"

#include <algorithm>

#include "base/containers/circular_deque.h"
#include "base/functional/bind.h"
#include "base/location.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/run_loop.h"
#include "base/scoped_clear_last_error.h"
#include "base/strings/string_number_conversions.h"
#include "base/task/single_thread_task_runner.h"
#include "base/test/scoped_feature_list.h"
#include "base/threading/thread.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "build/chromeos_buildflags.h"
#include "net/base/features.h"
#include "net/base/io_buffer.h"
#include "net/base/ip_address.h"
#include "net/base/ip_endpoint.h"
#include "net/base/net_errors.h"
#include "net/base/network_interfaces.h"
#include "net/base/test_completion_callback.h"
#include "net/log/net_log_event_type.h"
#include "net/log/net_log_source.h"
#include "net/log/test_net_log.h"
#include "net/log/test_net_log_util.h"
#include "net/socket/socket_test_util.h"
#include "net/socket/udp_client_socket.h"
#include "net/socket/udp_server_socket.h"
#include "net/socket/udp_socket_global_limits.h"
#include "net/test/gtest_util.h"
#include "net/test/test_with_task_environment.h"
#include "net/traffic_annotation/network_traffic_annotation_test_helper.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "testing/platform_test.h"

#if !BUILDFLAG(IS_WIN)
#include <netinet/in.h>
#include <sys/socket.h>
#else
#include <winsock2.h>
#endif

#if BUILDFLAG(IS_ANDROID)
#include "base/android/build_info.h"
#include "net/android/network_change_notifier_factory_android.h"
#include "net/base/network_change_notifier.h"
#endif

#if BUILDFLAG(IS_IOS)
#include <TargetConditionals.h>
#endif

#if BUILDFLAG(IS_MAC)
#include "base/mac/mac_util.h"
#endif  // BUILDFLAG(IS_MAC)

IsError;
IsOk;
DoAll;
Not;

namespace net {

namespace {

// Creates an address from ip address and port and writes it to |*address|.
bool CreateUDPAddress(const std::string& ip_str,
                      uint16_t port,
                      IPEndPoint* address) { … }

class UDPSocketTest : public PlatformTest, public WithTaskEnvironment { … };

const int UDPSocketTest::kMaxRead;

void ReadCompleteCallback(int* result_out,
                          base::OnceClosure callback,
                          int result) { … }

void UDPSocketTest::ConnectTest(bool use_nonblocking_io, bool use_async) { … }

TEST_F(UDPSocketTest, Connect) { … }

#if BUILDFLAG(IS_WIN)
TEST_F(UDPSocketTest, ConnectNonBlocking) {
  ConnectTest(true, false);
  ConnectTest(true, true);
}
#endif

TEST_F(UDPSocketTest, PartialRecv) { … }

#if BUILDFLAG(IS_APPLE) || BUILDFLAG(IS_ANDROID)
// - MacOS: requires root permissions on OSX 10.7+.
// - Android: devices attached to testbots don't have default network, so
// broadcasting to 255.255.255.255 returns error -109 (Address not reachable).
// crbug.com/139144.
#define MAYBE_LocalBroadcast …
#else
#define MAYBE_LocalBroadcast …
#endif
TEST_F(UDPSocketTest, MAYBE_LocalBroadcast) { … }

// ConnectRandomBind verifies RANDOM_BIND is handled correctly. It connects
// 1000 sockets and then verifies that the allocated port numbers satisfy the
// following 2 conditions:
//  1. Range from min port value to max is greater than 10000.
//  2. There is at least one port in the 5 buckets in the [min, max] range.
//
// These conditions are not enough to verify that the port numbers are truly
// random, but they are enough to protect from most common non-random port
// allocation strategies (e.g. counter, pool of available ports, etc.) False
// positive result is theoretically possible, but its probability is negligible.
TEST_F(UDPSocketTest, ConnectRandomBind) { … }

TEST_F(UDPSocketTest, ConnectFail) { … }

// Similar to ConnectFail but UDPSocket adopts an opened socket instead of
// opening one directly.
TEST_F(UDPSocketTest, AdoptedSocket) { … }

// Tests that UDPSocket updates the global counter correctly.
TEST_F(UDPSocketTest, LimitAdoptSocket) { … }

// In this test, we verify that connect() on a socket will have the effect
// of filtering reads on this socket only to data read from the destination
// we connected to.
//
// The purpose of this test is that some documentation indicates that connect
// binds the client's sends to send to a particular server endpoint, but does
// not bind the client's reads to only be from that endpoint, and that we need
// to always use recvfrom() to disambiguate.
TEST_F(UDPSocketTest, VerifyConnectBindsAddr) { … }

TEST_F(UDPSocketTest, ClientGetLocalPeerAddresses) { … }

TEST_F(UDPSocketTest, ServerGetLocalAddress) { … }

TEST_F(UDPSocketTest, ServerGetPeerAddress) { … }

TEST_F(UDPSocketTest, ClientSetDoNotFragment) { … }

TEST_F(UDPSocketTest, ServerSetDoNotFragment) { … }

// Close the socket while read is pending.
TEST_F(UDPSocketTest, CloseWithPendingRead) { … }

// Some Android devices do not support multicast.
// The ones supporting multicast need WifiManager.MulitcastLock to enable it.
// http://goo.gl/jjAk9
#if !BUILDFLAG(IS_ANDROID)
TEST_F(UDPSocketTest, JoinMulticastGroup) { … }

// TODO(crbug.com/40620614): failing on device on iOS 12.2.
// TODO(crbug.com/40189274): flaky on Mac 11.
#if BUILDFLAG(IS_IOS) || BUILDFLAG(IS_MAC)
#define MAYBE_SharedMulticastAddress …
#else
#define MAYBE_SharedMulticastAddress …
#endif
TEST_F(UDPSocketTest, MAYBE_SharedMulticastAddress) { … }
#endif  // !BUILDFLAG(IS_ANDROID)

TEST_F(UDPSocketTest, MulticastOptions) { … }

// Checking that DSCP bits are set correctly is difficult,
// but let's check that the code doesn't crash at least.
TEST_F(UDPSocketTest, SetDSCP) { … }

// Send DSCP + ECN marked packets from server to client and verify the TOS
// bytes that arrive.
TEST_F(UDPSocketTest, VerifyDscpAndEcnExchangeV4) { … }

// Send DSCP + ECN marked packets from server to client and verify the TOS
// bytes that arrive.
TEST_F(UDPSocketTest, VerifyDscpAndEcnExchangeV6) { … }

// Send DSCP + ECN marked packets from client to a dual-stack server and verify
// the TOS bytes that arrive.
TEST_F(UDPSocketTest, VerifyDscpAndEcnExchangeDualStack) { … }

// Send DSCP + ECN marked packets from client to a dual-stack server and verify
// the TOS bytes that arrive.
TEST_F(UDPSocketTest, VerifyDscpAndEcnExchangeDualStackV4Mapped) { … }

// For windows, test with Nonblocking sockets. For other platforms, this test
// is identical to VerifyDscpAndEcnExchange, above.
TEST_F(UDPSocketTest, VerifyDscpAndEcnExchangeNonBlocking) { … }

TEST_F(UDPSocketTest, ConnectUsingNetwork) { … }

TEST_F(UDPSocketTest, ConnectUsingNetworkAsync) { … }

}  // namespace

#if BUILDFLAG(IS_WIN)

namespace {

const HANDLE kFakeHandle1 = (HANDLE)12;
const HANDLE kFakeHandle2 = (HANDLE)13;

const QOS_FLOWID kFakeFlowId1 = (QOS_FLOWID)27;
const QOS_FLOWID kFakeFlowId2 = (QOS_FLOWID)38;

class TestUDPSocketWin : public UDPSocketWin {
 public:
  TestUDPSocketWin(QwaveApi* qos,
                   DatagramSocket::BindType bind_type,
                   net::NetLog* net_log,
                   const net::NetLogSource& source)
      : UDPSocketWin(bind_type, net_log, source), qos_(qos) {}

  TestUDPSocketWin(const TestUDPSocketWin&) = delete;
  TestUDPSocketWin& operator=(const TestUDPSocketWin&) = delete;

  // Overriding GetQwaveApi causes the test class to use the injected mock
  // QwaveApi instance instead of the singleton.
  QwaveApi* GetQwaveApi() const override { return qos_; }

 private:
  raw_ptr<QwaveApi> qos_;
};

class MockQwaveApi : public QwaveApi {
 public:
  MOCK_CONST_METHOD0(qwave_supported, bool());
  MOCK_METHOD0(OnFatalError, void());
  MOCK_METHOD2(CreateHandle, BOOL(PQOS_VERSION version, PHANDLE handle));
  MOCK_METHOD1(CloseHandle, BOOL(HANDLE handle));
  MOCK_METHOD6(AddSocketToFlow,
               BOOL(HANDLE handle,
                    SOCKET socket,
                    PSOCKADDR addr,
                    QOS_TRAFFIC_TYPE traffic_type,
                    DWORD flags,
                    PQOS_FLOWID flow_id));

  MOCK_METHOD4(
      RemoveSocketFromFlow,
      BOOL(HANDLE handle, SOCKET socket, QOS_FLOWID flow_id, DWORD reserved));
  MOCK_METHOD7(SetFlow,
               BOOL(HANDLE handle,
                    QOS_FLOWID flow_id,
                    QOS_SET_FLOW op,
                    ULONG size,
                    PVOID data,
                    DWORD reserved,
                    LPOVERLAPPED overlapped));
};

std::unique_ptr<UDPSocket> OpenedDscpTestClient(QwaveApi* api,
                                                IPEndPoint bind_address) {
  auto client = std::make_unique<TestUDPSocketWin>(
      api, DatagramSocket::DEFAULT_BIND, nullptr, NetLogSource());
  int rv = client->Open(bind_address.GetFamily());
  EXPECT_THAT(rv, IsOk());

  return client;
}

std::unique_ptr<UDPSocket> ConnectedDscpTestClient(QwaveApi* api) {
  IPEndPoint bind_address;
  // We need a real IP, but we won't actually send anything to it.
  EXPECT_TRUE(CreateUDPAddress("8.8.8.8", 9999, &bind_address));
  auto client = OpenedDscpTestClient(api, bind_address);
  EXPECT_THAT(client->Connect(bind_address), IsOk());
  return client;
}

std::unique_ptr<UDPSocket> UnconnectedDscpTestClient(QwaveApi* api) {
  IPEndPoint bind_address;
  EXPECT_TRUE(CreateUDPAddress("0.0.0.0", 9999, &bind_address));
  auto client = OpenedDscpTestClient(api, bind_address);
  EXPECT_THAT(client->Bind(bind_address), IsOk());
  return client;
}

}  // namespace

using ::testing::Return;
using ::testing::SetArgPointee;
using ::testing::_;

TEST_F(UDPSocketTest, SetDSCPNoopIfPassedNoChange) {
  MockQwaveApi api;
  EXPECT_CALL(api, qwave_supported()).WillRepeatedly(Return(true));

  EXPECT_CALL(api, AddSocketToFlow(_, _, _, _, _, _)).Times(0);
  std::unique_ptr<UDPSocket> client = ConnectedDscpTestClient(&api);
  EXPECT_THAT(client->SetDiffServCodePoint(DSCP_NO_CHANGE), IsOk());
}

TEST_F(UDPSocketTest, SetDSCPFailsIfQOSDoesntLink) {
  MockQwaveApi api;
  EXPECT_CALL(api, qwave_supported()).WillRepeatedly(Return(false));
  EXPECT_CALL(api, CreateHandle(_, _)).Times(0);

  std::unique_ptr<UDPSocket> client = ConnectedDscpTestClient(&api);
  EXPECT_EQ(ERR_NOT_IMPLEMENTED, client->SetDiffServCodePoint(DSCP_AF41));
}

TEST_F(UDPSocketTest, SetDSCPFailsIfHandleCantBeCreated) {
  MockQwaveApi api;
  EXPECT_CALL(api, qwave_supported()).WillRepeatedly(Return(true));
  EXPECT_CALL(api, CreateHandle(_, _)).WillOnce(Return(false));
  EXPECT_CALL(api, OnFatalError()).Times(1);

  std::unique_ptr<UDPSocket> client = ConnectedDscpTestClient(&api);
  EXPECT_EQ(ERR_INVALID_HANDLE, client->SetDiffServCodePoint(DSCP_AF41));

  RunUntilIdle();

  EXPECT_CALL(api, qwave_supported()).WillRepeatedly(Return(false));
  EXPECT_EQ(ERR_NOT_IMPLEMENTED, client->SetDiffServCodePoint(DSCP_AF41));
}

MATCHER_P(DscpPointee, dscp, "") {
  return *(DWORD*)arg == (DWORD)dscp;
}

TEST_F(UDPSocketTest, ConnectedSocketDelayedInitAndUpdate) {
  MockQwaveApi api;
  std::unique_ptr<UDPSocket> client = ConnectedDscpTestClient(&api);
  EXPECT_CALL(api, qwave_supported()).WillRepeatedly(Return(true));
  EXPECT_CALL(api, CreateHandle(_, _))
      .WillOnce(DoAll(SetArgPointee<1>(kFakeHandle1), Return(true)));

  EXPECT_CALL(api, AddSocketToFlow(_, _, _, _, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId1), Return(true)));
  EXPECT_CALL(api, SetFlow(_, _, _, _, _, _, _));

  // First set on connected sockets will fail since init is async and
  // we haven't given the runloop a chance to execute the callback.
  EXPECT_EQ(ERR_INVALID_HANDLE, client->SetDiffServCodePoint(DSCP_AF41));
  RunUntilIdle();
  EXPECT_THAT(client->SetDiffServCodePoint(DSCP_AF41), IsOk());

  // New dscp value should reset the flow.
  EXPECT_CALL(api, RemoveSocketFromFlow(_, _, kFakeFlowId1, _));
  EXPECT_CALL(api, AddSocketToFlow(_, _, _, QOSTrafficTypeBestEffort, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId2), Return(true)));
  EXPECT_CALL(api, SetFlow(_, _, QOSSetOutgoingDSCPValue, _,
                           DscpPointee(DSCP_DEFAULT), _, _));
  EXPECT_THAT(client->SetDiffServCodePoint(DSCP_DEFAULT), IsOk());

  // Called from DscpManager destructor.
  EXPECT_CALL(api, RemoveSocketFromFlow(_, _, kFakeFlowId2, _));
  EXPECT_CALL(api, CloseHandle(kFakeHandle1));
}

TEST_F(UDPSocketTest, UnonnectedSocketDelayedInitAndUpdate) {
  MockQwaveApi api;
  EXPECT_CALL(api, qwave_supported()).WillRepeatedly(Return(true));
  EXPECT_CALL(api, CreateHandle(_, _))
      .WillOnce(DoAll(SetArgPointee<1>(kFakeHandle1), Return(true)));

  // CreateHandle won't have completed yet.  Set passes.
  std::unique_ptr<UDPSocket> client = UnconnectedDscpTestClient(&api);
  EXPECT_THAT(client->SetDiffServCodePoint(DSCP_AF41), IsOk());

  RunUntilIdle();
  EXPECT_THAT(client->SetDiffServCodePoint(DSCP_AF42), IsOk());

  // Called from DscpManager destructor.
  EXPECT_CALL(api, CloseHandle(kFakeHandle1));
}

// TODO(zstein): Mocking out DscpManager might be simpler here
// (just verify that DscpManager::Set and DscpManager::PrepareForSend are
// called).
TEST_F(UDPSocketTest, SendToCallsQwaveApis) {
  MockQwaveApi api;
  std::unique_ptr<UDPSocket> client = UnconnectedDscpTestClient(&api);
  EXPECT_CALL(api, qwave_supported()).WillRepeatedly(Return(true));
  EXPECT_CALL(api, CreateHandle(_, _))
      .WillOnce(DoAll(SetArgPointee<1>(kFakeHandle1), Return(true)));
  EXPECT_THAT(client->SetDiffServCodePoint(DSCP_AF41), IsOk());
  RunUntilIdle();

  EXPECT_CALL(api, AddSocketToFlow(_, _, _, _, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId1), Return(true)));
  EXPECT_CALL(api, SetFlow(_, _, _, _, _, _, _));
  std::string simple_message("hello world");
  IPEndPoint server_address(IPAddress::IPv4Localhost(), 9438);
  int rv = SendToSocket(client.get(), simple_message, server_address);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));

  // TODO(zstein): Move to second test case (Qwave APIs called once per address)
  rv = SendToSocket(client.get(), simple_message, server_address);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));

  // TODO(zstein): Move to third test case (Qwave APIs called for each
  // destination address).
  EXPECT_CALL(api, AddSocketToFlow(_, _, _, _, _, _)).WillOnce(Return(true));
  IPEndPoint server_address2(IPAddress::IPv4Localhost(), 9439);

  rv = SendToSocket(client.get(), simple_message, server_address2);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));

  // Called from DscpManager destructor.
  EXPECT_CALL(api, RemoveSocketFromFlow(_, _, _, _));
  EXPECT_CALL(api, CloseHandle(kFakeHandle1));
}

TEST_F(UDPSocketTest, SendToCallsApisAfterDeferredInit) {
  MockQwaveApi api;
  std::unique_ptr<UDPSocket> client = UnconnectedDscpTestClient(&api);
  EXPECT_CALL(api, qwave_supported()).WillRepeatedly(Return(true));
  EXPECT_CALL(api, CreateHandle(_, _))
      .WillOnce(DoAll(SetArgPointee<1>(kFakeHandle1), Return(true)));

  // SetDiffServCodepoint works even if qos api hasn't finished initing.
  EXPECT_THAT(client->SetDiffServCodePoint(DSCP_CS7), IsOk());

  std::string simple_message("hello world");
  IPEndPoint server_address(IPAddress::IPv4Localhost(), 9438);

  // SendTo works, but doesn't yet apply TOS
  EXPECT_CALL(api, AddSocketToFlow(_, _, _, _, _, _)).Times(0);
  int rv = SendToSocket(client.get(), simple_message, server_address);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));

  RunUntilIdle();
  // Now we're initialized, SendTo triggers qos calls with correct codepoint.
  EXPECT_CALL(api, AddSocketToFlow(_, _, _, QOSTrafficTypeControl, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId1), Return(true)));
  EXPECT_CALL(api, SetFlow(_, _, _, _, _, _, _)).WillOnce(Return(true));
  rv = SendToSocket(client.get(), simple_message, server_address);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));

  // Called from DscpManager destructor.
  EXPECT_CALL(api, RemoveSocketFromFlow(_, _, kFakeFlowId1, _));
  EXPECT_CALL(api, CloseHandle(kFakeHandle1));
}

class DscpManagerTest : public TestWithTaskEnvironment {
 protected:
  DscpManagerTest() {
    EXPECT_CALL(api_, qwave_supported()).WillRepeatedly(Return(true));
    EXPECT_CALL(api_, CreateHandle(_, _))
        .WillOnce(DoAll(SetArgPointee<1>(kFakeHandle1), Return(true)));
    dscp_manager_ = std::make_unique<DscpManager>(&api_, INVALID_SOCKET);

    CreateUDPAddress("1.2.3.4", 9001, &address1_);
    CreateUDPAddress("1234:5678:90ab:cdef:1234:5678:90ab:cdef", 9002,
                     &address2_);
  }

  MockQwaveApi api_;
  std::unique_ptr<DscpManager> dscp_manager_;

  IPEndPoint address1_;
  IPEndPoint address2_;
};

TEST_F(DscpManagerTest, PrepareForSendIsNoopIfNoSet) {
  RunUntilIdle();
  dscp_manager_->PrepareForSend(address1_);
}

TEST_F(DscpManagerTest, PrepareForSendCallsQwaveApisAfterSet) {
  RunUntilIdle();
  dscp_manager_->Set(DSCP_CS2);

  // AddSocketToFlow should be called for each address.
  // SetFlow should only be called when the flow is first created.
  EXPECT_CALL(api_, AddSocketToFlow(_, _, _, _, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId1), Return(true)));
  EXPECT_CALL(api_, SetFlow(_, kFakeFlowId1, _, _, _, _, _));
  dscp_manager_->PrepareForSend(address1_);

  EXPECT_CALL(api_, AddSocketToFlow(_, _, _, _, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId1), Return(true)));
  EXPECT_CALL(api_, SetFlow(_, _, _, _, _, _, _)).Times(0);
  dscp_manager_->PrepareForSend(address2_);

  // Called from DscpManager destructor.
  EXPECT_CALL(api_, RemoveSocketFromFlow(_, _, kFakeFlowId1, _));
  EXPECT_CALL(api_, CloseHandle(kFakeHandle1));
}

TEST_F(DscpManagerTest, PrepareForSendCallsQwaveApisOncePerAddress) {
  RunUntilIdle();
  dscp_manager_->Set(DSCP_CS2);

  EXPECT_CALL(api_, AddSocketToFlow(_, _, _, _, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId1), Return(true)));
  EXPECT_CALL(api_, SetFlow(_, kFakeFlowId1, _, _, _, _, _));
  dscp_manager_->PrepareForSend(address1_);
  EXPECT_CALL(api_, AddSocketToFlow(_, _, _, _, _, _)).Times(0);
  EXPECT_CALL(api_, SetFlow(_, _, _, _, _, _, _)).Times(0);
  dscp_manager_->PrepareForSend(address1_);

  // Called from DscpManager destructor.
  EXPECT_CALL(api_, RemoveSocketFromFlow(_, _, kFakeFlowId1, _));
  EXPECT_CALL(api_, CloseHandle(kFakeHandle1));
}

TEST_F(DscpManagerTest, SetDestroysExistingFlow) {
  RunUntilIdle();
  dscp_manager_->Set(DSCP_CS2);

  EXPECT_CALL(api_, AddSocketToFlow(_, _, _, _, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId1), Return(true)));
  EXPECT_CALL(api_, SetFlow(_, kFakeFlowId1, _, _, _, _, _));
  dscp_manager_->PrepareForSend(address1_);

  // Calling Set should destroy the existing flow.
  // TODO(zstein): Verify that RemoveSocketFromFlow with no address
  // destroys the flow for all destinations.
  EXPECT_CALL(api_, RemoveSocketFromFlow(_, NULL, kFakeFlowId1, _));
  dscp_manager_->Set(DSCP_CS5);

  EXPECT_CALL(api_, AddSocketToFlow(_, _, _, _, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId2), Return(true)));
  EXPECT_CALL(api_, SetFlow(_, kFakeFlowId2, _, _, _, _, _));
  dscp_manager_->PrepareForSend(address1_);

  // Called from DscpManager destructor.
  EXPECT_CALL(api_, RemoveSocketFromFlow(_, _, kFakeFlowId2, _));
  EXPECT_CALL(api_, CloseHandle(kFakeHandle1));
}

TEST_F(DscpManagerTest, SocketReAddedOnRecreateHandle) {
  RunUntilIdle();
  dscp_manager_->Set(DSCP_CS2);

  // First Set and Send work fine.
  EXPECT_CALL(api_, AddSocketToFlow(_, _, _, _, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId1), Return(true)));
  EXPECT_CALL(api_, SetFlow(_, kFakeFlowId1, _, _, _, _, _))
      .WillOnce(Return(true));
  EXPECT_THAT(dscp_manager_->PrepareForSend(address1_), IsOk());

  // Make Second flow operation fail (requires resetting the codepoint).
  EXPECT_CALL(api_, RemoveSocketFromFlow(_, _, kFakeFlowId1, _))
      .WillOnce(Return(true));
  dscp_manager_->Set(DSCP_CS7);

  auto error = std::make_unique<base::ScopedClearLastError>();
  ::SetLastError(ERROR_DEVICE_REINITIALIZATION_NEEDED);
  EXPECT_CALL(api_, AddSocketToFlow(_, _, _, _, _, _)).WillOnce(Return(false));
  EXPECT_CALL(api_, SetFlow(_, _, _, _, _, _, _)).Times(0);
  EXPECT_CALL(api_, CloseHandle(kFakeHandle1));
  EXPECT_CALL(api_, CreateHandle(_, _))
      .WillOnce(DoAll(SetArgPointee<1>(kFakeHandle2), Return(true)));
  EXPECT_EQ(ERR_INVALID_HANDLE, dscp_manager_->PrepareForSend(address1_));
  error = nullptr;
  RunUntilIdle();

  // Next Send should work fine, without requiring another Set
  EXPECT_CALL(api_, AddSocketToFlow(_, _, _, QOSTrafficTypeControl, _, _))
      .WillOnce(DoAll(SetArgPointee<5>(kFakeFlowId2), Return(true)));
  EXPECT_CALL(api_, SetFlow(_, kFakeFlowId2, _, _, _, _, _))
      .WillOnce(Return(true));
  EXPECT_THAT(dscp_manager_->PrepareForSend(address1_), IsOk());

  // Called from DscpManager destructor.
  EXPECT_CALL(api_, RemoveSocketFromFlow(_, _, kFakeFlowId2, _));
  EXPECT_CALL(api_, CloseHandle(kFakeHandle2));
}
#endif

TEST_F(UDPSocketTest, ReadWithSocketOptimization) { … }

// Tests that read from a socket correctly returns
// |ERR_MSG_TOO_BIG| when the buffer is too small and
// returns the actual message when it fits the buffer.
// For the optimized path, the buffer size should be at least
// 1 byte greater than the message.
TEST_F(UDPSocketTest, ReadWithSocketOptimizationTruncation) { … }

// On Android, where socket tagging is supported, verify that UDPSocket::Tag
// works as expected.
#if BUILDFLAG(IS_ANDROID)
TEST_F(UDPSocketTest, Tag) {
  if (!CanGetTaggedBytes()) {
    DVLOG(0) << "Skipping test - GetTaggedBytes unsupported.";
    return;
  }

  UDPServerSocket server(nullptr, NetLogSource());
  ASSERT_THAT(server.Listen(IPEndPoint(IPAddress::IPv4Localhost(), 0)), IsOk());
  IPEndPoint server_address;
  ASSERT_THAT(server.GetLocalAddress(&server_address), IsOk());

  UDPClientSocket client(DatagramSocket::DEFAULT_BIND, nullptr, NetLogSource());
  ASSERT_THAT(client.Connect(server_address), IsOk());

  // Verify UDP packets are tagged and counted properly.
  int32_t tag_val1 = 0x12345678;
  uint64_t old_traffic = GetTaggedBytes(tag_val1);
  SocketTag tag1(SocketTag::UNSET_UID, tag_val1);
  client.ApplySocketTag(tag1);
  // Client sends to the server.
  std::string simple_message("hello world!");
  int rv = WriteSocket(&client, simple_message);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));
  // Server waits for message.
  std::string str = RecvFromSocket(&server);
  EXPECT_EQ(simple_message, str);
  // Server echoes reply.
  rv = SendToSocket(&server, simple_message);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));
  // Client waits for response.
  str = ReadSocket(&client);
  EXPECT_EQ(simple_message, str);
  EXPECT_GT(GetTaggedBytes(tag_val1), old_traffic);

  // Verify socket can be retagged with a new value and the current process's
  // UID.
  int32_t tag_val2 = 0x87654321;
  old_traffic = GetTaggedBytes(tag_val2);
  SocketTag tag2(getuid(), tag_val2);
  client.ApplySocketTag(tag2);
  // Client sends to the server.
  rv = WriteSocket(&client, simple_message);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));
  // Server waits for message.
  str = RecvFromSocket(&server);
  EXPECT_EQ(simple_message, str);
  // Server echoes reply.
  rv = SendToSocket(&server, simple_message);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));
  // Client waits for response.
  str = ReadSocket(&client);
  EXPECT_EQ(simple_message, str);
  EXPECT_GT(GetTaggedBytes(tag_val2), old_traffic);

  // Verify socket can be retagged with a new value and the current process's
  // UID.
  old_traffic = GetTaggedBytes(tag_val1);
  client.ApplySocketTag(tag1);
  // Client sends to the server.
  rv = WriteSocket(&client, simple_message);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));
  // Server waits for message.
  str = RecvFromSocket(&server);
  EXPECT_EQ(simple_message, str);
  // Server echoes reply.
  rv = SendToSocket(&server, simple_message);
  EXPECT_EQ(simple_message.length(), static_cast<size_t>(rv));
  // Client waits for response.
  str = ReadSocket(&client);
  EXPECT_EQ(simple_message, str);
  EXPECT_GT(GetTaggedBytes(tag_val1), old_traffic);
}

TEST_F(UDPSocketTest, BindToNetwork) {
  // The specific value of this address doesn't really matter, and no
  // server needs to be running here. The test only needs to call
  // Connect() and won't send any datagrams.
  const IPEndPoint fake_server_address(IPAddress::IPv4Localhost(), 8080);
  NetworkChangeNotifierFactoryAndroid ncn_factory;
  NetworkChangeNotifier::DisableForTest ncn_disable_for_test;
  std::unique_ptr<NetworkChangeNotifier> ncn(ncn_factory.CreateInstance());
  if (!NetworkChangeNotifier::AreNetworkHandlesSupported())
    GTEST_SKIP() << "Network handles are required to test BindToNetwork.";

  // Binding the socket to a not existing network should fail at connect time.
  const handles::NetworkHandle wrong_network_handle = 65536;
  UDPClientSocket wrong_socket(DatagramSocket::RANDOM_BIND, nullptr,
                               NetLogSource(), wrong_network_handle);
  // Different Android versions might report different errors. Hence, just check
  // what shouldn't happen.
  int rv = wrong_socket.Connect(fake_server_address);
  EXPECT_NE(OK, rv);
  EXPECT_NE(ERR_NOT_IMPLEMENTED, rv);
  EXPECT_NE(wrong_network_handle, wrong_socket.GetBoundNetwork());

  // Binding the socket to an existing network should succeed.
  const handles::NetworkHandle network_handle =
      NetworkChangeNotifier::GetDefaultNetwork();
  if (network_handle != handles::kInvalidNetworkHandle) {
    UDPClientSocket correct_socket(DatagramSocket::RANDOM_BIND, nullptr,
                                   NetLogSource(), network_handle);
    EXPECT_EQ(OK, correct_socket.Connect(fake_server_address));
    EXPECT_EQ(network_handle, correct_socket.GetBoundNetwork());
  }
}

#endif  // BUILDFLAG(IS_ANDROID)

// Scoped helper to override the process-wide UDP socket limit.
class OverrideUDPSocketLimit { … };

// Tests that UDPClientSocket respects the global UDP socket limits.
TEST_F(UDPSocketTest, LimitClientSocket) { … }

// Tests that UDPSocketClient updates the global counter
// correctly when Connect() fails.
TEST_F(UDPSocketTest, LimitConnectFail) { … }

// Tests allocating UDPClientSockets and Connect()ing them in parallel.
//
// This is primarily intended for coverage under TSAN, to check for races
// enforcing the global socket counter.
TEST_F(UDPSocketTest, LimitConnectMultithreaded) { … }

}  // namespace net