// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "shill/passive_link_monitor.h"

#include <net/if_arp.h>

#include <string>

#include <gtest/gtest.h>

#include "shill/logging.h"
#include "shill/mock_connection.h"
#include "shill/mock_control.h"
#include "shill/mock_device_info.h"
#include "shill/mock_event_dispatcher.h"
#include "shill/mock_log.h"
#include "shill/mock_manager.h"
#include "shill/net/arp_client_test_helper.h"
#include "shill/net/arp_packet.h"
#include "shill/net/byte_string.h"
#include "shill/net/ip_address.h"
#include "shill/net/mock_arp_client.h"
#include "shill/net/mock_io_handler_factory.h"

using base::Bind;
using base::Unretained;
using testing::_;
using testing::AnyNumber;
using testing::HasSubstr;
using testing::Mock;
using testing::NiceMock;
using testing::Return;
using testing::ReturnRef;
using testing::StrictMock;
using testing::Test;

namespace shill {

namespace {
const char kInterfaceName[] = "test-interface";
const char kLocalIPAddress[] = "10.0.1.1";
const uint8_t kLocalMacAddress[] = {0, 1, 2, 3, 4, 5};
const char kRemoteIPAddress[] = "10.0.1.2";
const uint8_t kRemoteMacAddress[] = {6, 7, 8, 9, 10, 11};
}  // namespace

class ResultCallbackObserver {
 public:
  ResultCallbackObserver()
      : result_callback_(Bind(&ResultCallbackObserver::OnResultCallback,
                              Unretained(this))) {}
  virtual ~ResultCallbackObserver() = default;

  MOCK_METHOD(void, OnResultCallback, (bool));

  const PassiveLinkMonitor::ResultCallback result_callback() const {
    return result_callback_;
  }

 private:
  PassiveLinkMonitor::ResultCallback result_callback_;

  DISALLOW_COPY_AND_ASSIGN(ResultCallbackObserver);
};

class PassiveLinkMonitorTest : public Test {
 public:
  PassiveLinkMonitorTest()
      : manager_(&control_, &dispatcher_, nullptr),
        device_info_(&manager_),
        connection_(new StrictMock<MockConnection>(&device_info_)),
        client_(new MockArpClient()),
        client_test_helper_(client_),
        link_monitor_(connection_, &dispatcher_, observer_.result_callback()),
        interface_name_(kInterfaceName) {
    link_monitor_.io_handler_factory_ = &io_handler_factory_;
  }

  ~PassiveLinkMonitorTest() override = default;

  void SetUp() override {
    ScopeLogger::GetInstance()->EnableScopesByName("link");
    ScopeLogger::GetInstance()->set_verbose_level(4);
    link_monitor_.arp_client_.reset(client_);

    EXPECT_CALL(*connection_, interface_name())
        .WillRepeatedly(ReturnRef(interface_name_));
  }

  void TearDown() override {
    ScopeLogger::GetInstance()->EnableScopesByName("-link");
    ScopeLogger::GetInstance()->set_verbose_level(0);
  }

  void ReceiveArpPacket(uint16_t operation) {
    client_test_helper_.GeneratePacket(
        operation, IPAddress(kLocalIPAddress),
        ByteString(kLocalMacAddress, arraysize(kLocalMacAddress)),
        IPAddress(kRemoteIPAddress),
        ByteString(kRemoteMacAddress, arraysize(kRemoteMacAddress)));
    link_monitor_.ReceiveRequest(0);
  }

  void MonitorCompleted(bool status) { link_monitor_.MonitorCompleted(status); }

  void InvokeCycleTimeoutHandler() { link_monitor_.CycleTimeoutHandler(); }

  void SetCurrentCycleStats(int num_requests_received, int num_cycles_passed) {
    link_monitor_.num_requests_received_ = num_requests_received;
    link_monitor_.num_cycles_passed_ = num_cycles_passed;
  }

  void VerifyCurrentCycleStats(int num_requests_received,
                               int num_cycles_passed) {
    EXPECT_EQ(num_requests_received, link_monitor_.num_requests_received_);
    EXPECT_EQ(num_cycles_passed, link_monitor_.num_cycles_passed_);
  }

 protected:
  MockEventDispatcher dispatcher_;
  MockIOHandlerFactory io_handler_factory_;
  MockControl control_;
  MockManager manager_;
  NiceMock<MockDeviceInfo> device_info_;
  ResultCallbackObserver observer_;
  scoped_refptr<MockConnection> connection_;
  MockArpClient* client_;
  ArpClientTestHelper client_test_helper_;
  PassiveLinkMonitor link_monitor_;
  const std::string interface_name_;
};

TEST_F(PassiveLinkMonitorTest, StartFailedArpClient) {
  EXPECT_CALL(*client_, StartRequestListener()).WillOnce(Return(false));
  EXPECT_FALSE(link_monitor_.Start(PassiveLinkMonitor::kDefaultMonitorCycles));
}

TEST_F(PassiveLinkMonitorTest, StartSuccess) {
  EXPECT_CALL(*client_, StartRequestListener()).WillOnce(Return(true));
  EXPECT_CALL(io_handler_factory_,
              CreateIOReadyHandler(_, IOHandler::kModeInput, _))
      .Times(1);
  EXPECT_CALL(dispatcher_, PostDelayedTask(_, _, _)).Times(1);
  EXPECT_TRUE(link_monitor_.Start(PassiveLinkMonitor::kDefaultMonitorCycles));
}

TEST_F(PassiveLinkMonitorTest, Stop) {
  EXPECT_CALL(*client_, Stop()).Times(1);
  link_monitor_.Stop();
  Mock::VerifyAndClearExpectations(client_);
}

TEST_F(PassiveLinkMonitorTest, MonitorCompleted) {
  // Monitor failed.
  EXPECT_CALL(*client_, Stop()).Times(1);
  EXPECT_CALL(observer_, OnResultCallback(false)).Times(1);
  MonitorCompleted(false);
  Mock::VerifyAndClearExpectations(client_);
  Mock::VerifyAndClearExpectations(&observer_);

  // Monitor succeed.
  EXPECT_CALL(*client_, Stop()).Times(1);
  EXPECT_CALL(observer_, OnResultCallback(true)).Times(1);
  MonitorCompleted(true);
  Mock::VerifyAndClearExpectations(client_);
  Mock::VerifyAndClearExpectations(&observer_);
}

TEST_F(PassiveLinkMonitorTest, ReceiveArpReply) {
  // Setup initial stats.
  const int kRequestReceived = 0;
  const int kCurrentCycle = 0;
  SetCurrentCycleStats(kRequestReceived, kCurrentCycle);
  ScopedMockLog log;
  EXPECT_CALL(log, Log(_, _, _)).Times(AnyNumber());
  EXPECT_CALL(log, Log(_, _, HasSubstr("This is not a request packet")))
      .Times(1);
  ReceiveArpPacket(ARPOP_REPLY);
  // Verify no change in receive count.
  VerifyCurrentCycleStats(kRequestReceived, kCurrentCycle);
  Mock::VerifyAndClearExpectations(&log);
}

TEST_F(PassiveLinkMonitorTest, ReceiveArpRequest) {
  // Setup initial stats.
  const int kRequestReceived = 0;
  const int kCurrentCycle = 0;
  SetCurrentCycleStats(kRequestReceived, kCurrentCycle);

  EXPECT_CALL(*client_, Stop()).Times(0);
  ReceiveArpPacket(ARPOP_REQUEST);
  ReceiveArpPacket(ARPOP_REQUEST);
  VerifyCurrentCycleStats(kRequestReceived + 2, kCurrentCycle);
  Mock::VerifyAndClearExpectations(client_);
}

TEST_F(PassiveLinkMonitorTest, ReceiveAllRequestsForCycle) {
  // 4 ARP requests received in the current cycle so far.
  const int kRequestReceived = 4;
  const int kCurrentCycle = 0;
  SetCurrentCycleStats(kRequestReceived, kCurrentCycle);

  // Received all required requests for a cycle, stop the ARP client.
  EXPECT_CALL(*client_, Stop()).Times(1);
  ReceiveArpPacket(ARPOP_REQUEST);
  Mock::VerifyAndClearExpectations(client_);
}

TEST_F(PassiveLinkMonitorTest, CycleFailed) {
  // 3 ARP requests received in the current cycle so far.
  const int kRequestReceived = 3;
  const int kCurrentCycle = 0;
  SetCurrentCycleStats(kRequestReceived, kCurrentCycle);

  // Monitor failed for the current cycle, post a task to perform cleanup and
  // invoke result callback.
  EXPECT_CALL(*client_, StartRequestListener()).Times(0);
  EXPECT_CALL(dispatcher_, PostDelayedTask(_, _, _)).Times(0);
  EXPECT_CALL(dispatcher_, PostTask(_, _)).Times(1);
  InvokeCycleTimeoutHandler();
}

TEST_F(PassiveLinkMonitorTest, CycleSucceed) {
  // 5 ARP requests received in the current cycle so far.
  const int kRequestReceived = 5;
  const int kCurrentCycle = 0;
  SetCurrentCycleStats(kRequestReceived, kCurrentCycle);

  // Monitor succeed for the current cycle, post a task to trigger a new cycle.
  EXPECT_CALL(*client_, StartRequestListener()).WillOnce(Return(true));
  EXPECT_CALL(dispatcher_, PostDelayedTask(_, _, _)).Times(1);
  EXPECT_CALL(dispatcher_, PostTask(_, _)).Times(0);
  InvokeCycleTimeoutHandler();
  // ARP request received count should be resetted.
  VerifyCurrentCycleStats(0, kCurrentCycle + 1);
}

TEST_F(PassiveLinkMonitorTest, AllCyclesCompleted) {
  // 5 ARP requests received in the current cycle so far.
  const int kRequestReceived = 5;
  const int kCurrentCycle = PassiveLinkMonitor::kDefaultMonitorCycles - 1;
  SetCurrentCycleStats(kRequestReceived, kCurrentCycle);

  // Monitor completed all the cycles, post a task to perform cleanup and
  // invoke result callback.
  EXPECT_CALL(dispatcher_, PostDelayedTask(_, _, _)).Times(0);
  EXPECT_CALL(dispatcher_, PostTask(_, _)).Times(1);
  InvokeCycleTimeoutHandler();
  VerifyCurrentCycleStats(0, PassiveLinkMonitor::kDefaultMonitorCycles);
}

}  // namespace shill