quic/core/quic_connection_test.cc

// Copyright (c) 2012 The Chromium 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 "net/third_party/quiche/src/quic/core/quic_connection.h"

#include <errno.h>

#include <memory>
#include <ostream>
#include <string>
#include <utility>

#include "net/third_party/quiche/src/quic/core/congestion_control/loss_detection_interface.h"
#include "net/third_party/quiche/src/quic/core/congestion_control/send_algorithm_interface.h"
#include "net/third_party/quiche/src/quic/core/crypto/null_decrypter.h"
#include "net/third_party/quiche/src/quic/core/crypto/null_encrypter.h"
#include "net/third_party/quiche/src/quic/core/crypto/quic_decrypter.h"
#include "net/third_party/quiche/src/quic/core/crypto/quic_encrypter.h"
#include "net/third_party/quiche/src/quic/core/quic_connection_id.h"
#include "net/third_party/quiche/src/quic/core/quic_packets.h"
#include "net/third_party/quiche/src/quic/core/quic_simple_buffer_allocator.h"
#include "net/third_party/quiche/src/quic/core/quic_types.h"
#include "net/third_party/quiche/src/quic/core/quic_utils.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_error_code_wrappers.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_expect_bug.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_flags.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_ptr_util.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_reference_counted.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_str_cat.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_string_piece.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_test.h"
#include "net/third_party/quiche/src/quic/test_tools/mock_clock.h"
#include "net/third_party/quiche/src/quic/test_tools/mock_random.h"
#include "net/third_party/quiche/src/quic/test_tools/quic_config_peer.h"
#include "net/third_party/quiche/src/quic/test_tools/quic_connection_peer.h"
#include "net/third_party/quiche/src/quic/test_tools/quic_framer_peer.h"
#include "net/third_party/quiche/src/quic/test_tools/quic_packet_creator_peer.h"
#include "net/third_party/quiche/src/quic/test_tools/quic_packet_generator_peer.h"
#include "net/third_party/quiche/src/quic/test_tools/quic_sent_packet_manager_peer.h"
#include "net/third_party/quiche/src/quic/test_tools/quic_test_utils.h"
#include "net/third_party/quiche/src/quic/test_tools/simple_data_producer.h"
#include "net/third_party/quiche/src/quic/test_tools/simple_quic_framer.h"
#include "net/third_party/quiche/src/quic/test_tools/simple_session_notifier.h"

using testing::_;
using testing::AnyNumber;
using testing::AtLeast;
using testing::DoAll;
using testing::Exactly;
using testing::Ge;
using testing::IgnoreResult;
using testing::InSequence;
using testing::Invoke;
using testing::InvokeWithoutArgs;
using testing::Lt;
using testing::Ref;
using testing::Return;
using testing::SaveArg;
using testing::SetArgPointee;
using testing::StrictMock;

namespace quic {
namespace test {
namespace {

const char data1[] = "foo data";
const char data2[] = "bar data";

const bool kHasStopWaiting = true;

const int kDefaultRetransmissionTimeMs = 500;

DiversificationNonce kTestDiversificationNonce = {
    'a', 'b', 'a', 'b', 'a', 'b', 'a', 'b', 'a', 'b', 'a',
    'b', 'a', 'b', 'a', 'b', 'a', 'b', 'a', 'b', 'a', 'b',
    'a', 'b', 'a', 'b', 'a', 'b', 'a', 'b', 'a', 'b',
};

const QuicSocketAddress kPeerAddress =
    QuicSocketAddress(QuicIpAddress::Loopback6(),
                      /*port=*/12345);
const QuicSocketAddress kSelfAddress =
    QuicSocketAddress(QuicIpAddress::Loopback6(),
                      /*port=*/443);

Perspective InvertPerspective(Perspective perspective) {
  return perspective == Perspective::IS_CLIENT ? Perspective::IS_SERVER
                                               : Perspective::IS_CLIENT;
}

QuicStreamId GetNthClientInitiatedStreamId(int n,
                                           QuicTransportVersion version) {
  return QuicUtils::GetHeadersStreamId(version) + n * 2;
}

QuicLongHeaderType EncryptionlevelToLongHeaderType(EncryptionLevel level) {
  switch (level) {
    case ENCRYPTION_INITIAL:
      return INITIAL;
    case ENCRYPTION_HANDSHAKE:
      return HANDSHAKE;
    case ENCRYPTION_ZERO_RTT:
      return ZERO_RTT_PROTECTED;
    case ENCRYPTION_FORWARD_SECURE:
      DCHECK(false);
      return INVALID_PACKET_TYPE;
    default:
      DCHECK(false);
      return INVALID_PACKET_TYPE;
  }
}

// TaggingEncrypter appends kTagSize bytes of |tag| to the end of each message.
class TaggingEncrypter : public QuicEncrypter {
 public:
  explicit TaggingEncrypter(uint8_t tag) : tag_(tag) {}
  TaggingEncrypter(const TaggingEncrypter&) = delete;
  TaggingEncrypter& operator=(const TaggingEncrypter&) = delete;

  ~TaggingEncrypter() override {}

  // QuicEncrypter interface.
  bool SetKey(QuicStringPiece key) override { return true; }

  bool SetNoncePrefix(QuicStringPiece nonce_prefix) override { return true; }

  bool SetIV(QuicStringPiece iv) override { return true; }

  bool SetHeaderProtectionKey(QuicStringPiece key) override { return true; }

  bool EncryptPacket(uint64_t packet_number,
                     QuicStringPiece associated_data,
                     QuicStringPiece plaintext,
                     char* output,
                     size_t* output_length,
                     size_t max_output_length) override {
    const size_t len = plaintext.size() + kTagSize;
    if (max_output_length < len) {
      return false;
    }
    // Memmove is safe for inplace encryption.
    memmove(output, plaintext.data(), plaintext.size());
    output += plaintext.size();
    memset(output, tag_, kTagSize);
    *output_length = len;
    return true;
  }

  std::string GenerateHeaderProtectionMask(QuicStringPiece sample) override {
    return std::string(5, 0);
  }

  size_t GetKeySize() const override { return 0; }
  size_t GetNoncePrefixSize() const override { return 0; }
  size_t GetIVSize() const override { return 0; }

  size_t GetMaxPlaintextSize(size_t ciphertext_size) const override {
    return ciphertext_size - kTagSize;
  }

  size_t GetCiphertextSize(size_t plaintext_size) const override {
    return plaintext_size + kTagSize;
  }

  QuicStringPiece GetKey() const override { return QuicStringPiece(); }

  QuicStringPiece GetNoncePrefix() const override { return QuicStringPiece(); }

 private:
  enum {
    kTagSize = 12,
  };

  const uint8_t tag_;
};

// TaggingDecrypter ensures that the final kTagSize bytes of the message all
// have the same value and then removes them.
class TaggingDecrypter : public QuicDecrypter {
 public:
  ~TaggingDecrypter() override {}

  // QuicDecrypter interface
  bool SetKey(QuicStringPiece key) override { return true; }

  bool SetNoncePrefix(QuicStringPiece nonce_prefix) override { return true; }

  bool SetIV(QuicStringPiece iv) override { return true; }

  bool SetHeaderProtectionKey(QuicStringPiece key) override { return true; }

  bool SetPreliminaryKey(QuicStringPiece key) override {
    QUIC_BUG << "should not be called";
    return false;
  }

  bool SetDiversificationNonce(const DiversificationNonce& key) override {
    return true;
  }

  bool DecryptPacket(uint64_t packet_number,
                     QuicStringPiece associated_data,
                     QuicStringPiece ciphertext,
                     char* output,
                     size_t* output_length,
                     size_t max_output_length) override {
    if (ciphertext.size() < kTagSize) {
      return false;
    }
    if (!CheckTag(ciphertext, GetTag(ciphertext))) {
      return false;
    }
    *output_length = ciphertext.size() - kTagSize;
    memcpy(output, ciphertext.data(), *output_length);
    return true;
  }

  std::string GenerateHeaderProtectionMask(
      QuicDataReader* sample_reader) override {
    return std::string(5, 0);
  }

  size_t GetKeySize() const override { return 0; }
  size_t GetIVSize() const override { return 0; }
  QuicStringPiece GetKey() const override { return QuicStringPiece(); }
  QuicStringPiece GetNoncePrefix() const override { return QuicStringPiece(); }
  // Use a distinct value starting with 0xFFFFFF, which is never used by TLS.
  uint32_t cipher_id() const override { return 0xFFFFFFF0; }

 protected:
  virtual uint8_t GetTag(QuicStringPiece ciphertext) {
    return ciphertext.data()[ciphertext.size() - 1];
  }

 private:
  enum {
    kTagSize = 12,
  };

  bool CheckTag(QuicStringPiece ciphertext, uint8_t tag) {
    for (size_t i = ciphertext.size() - kTagSize; i < ciphertext.size(); i++) {
      if (ciphertext.data()[i] != tag) {
        return false;
      }
    }

    return true;
  }
};

// StringTaggingDecrypter ensures that the final kTagSize bytes of the message
// match the expected value.
class StrictTaggingDecrypter : public TaggingDecrypter {
 public:
  explicit StrictTaggingDecrypter(uint8_t tag) : tag_(tag) {}
  ~StrictTaggingDecrypter() override {}

  // TaggingQuicDecrypter
  uint8_t GetTag(QuicStringPiece ciphertext) override { return tag_; }

  // Use a distinct value starting with 0xFFFFFF, which is never used by TLS.
  uint32_t cipher_id() const override { return 0xFFFFFFF1; }

 private:
  const uint8_t tag_;
};

class TestConnectionHelper : public QuicConnectionHelperInterface {
 public:
  TestConnectionHelper(MockClock* clock, MockRandom* random_generator)
      : clock_(clock), random_generator_(random_generator) {
    clock_->AdvanceTime(QuicTime::Delta::FromSeconds(1));
  }
  TestConnectionHelper(const TestConnectionHelper&) = delete;
  TestConnectionHelper& operator=(const TestConnectionHelper&) = delete;

  // QuicConnectionHelperInterface
  const QuicClock* GetClock() const override { return clock_; }

  QuicRandom* GetRandomGenerator() override { return random_generator_; }

  QuicBufferAllocator* GetStreamSendBufferAllocator() override {
    return &buffer_allocator_;
  }

 private:
  MockClock* clock_;
  MockRandom* random_generator_;
  SimpleBufferAllocator buffer_allocator_;
};

class TestAlarmFactory : public QuicAlarmFactory {
 public:
  class TestAlarm : public QuicAlarm {
   public:
    explicit TestAlarm(QuicArenaScopedPtr<QuicAlarm::Delegate> delegate)
        : QuicAlarm(std::move(delegate)) {}

    void SetImpl() override {}
    void CancelImpl() override {}
    using QuicAlarm::Fire;
  };

  TestAlarmFactory() {}
  TestAlarmFactory(const TestAlarmFactory&) = delete;
  TestAlarmFactory& operator=(const TestAlarmFactory&) = delete;

  QuicAlarm* CreateAlarm(QuicAlarm::Delegate* delegate) override {
    return new TestAlarm(QuicArenaScopedPtr<QuicAlarm::Delegate>(delegate));
  }

  QuicArenaScopedPtr<QuicAlarm> CreateAlarm(
      QuicArenaScopedPtr<QuicAlarm::Delegate> delegate,
      QuicConnectionArena* arena) override {
    return arena->New<TestAlarm>(std::move(delegate));
  }
};

class TestPacketWriter : public QuicPacketWriter {
 public:
  TestPacketWriter(ParsedQuicVersion version, MockClock* clock)
      : version_(version),
        framer_(SupportedVersions(version_), Perspective::IS_SERVER),
        last_packet_size_(0),
        write_blocked_(false),
        write_should_fail_(false),
        block_on_next_flush_(false),
        block_on_next_write_(false),
        next_packet_too_large_(false),
        always_get_packet_too_large_(false),
        is_write_blocked_data_buffered_(false),
        is_batch_mode_(false),
        final_bytes_of_last_packet_(0),
        final_bytes_of_previous_packet_(0),
        use_tagging_decrypter_(false),
        packets_write_attempts_(0),
        clock_(clock),
        write_pause_time_delta_(QuicTime::Delta::Zero()),
        max_packet_size_(kMaxOutgoingPacketSize),
        supports_release_time_(false) {}
  TestPacketWriter(const TestPacketWriter&) = delete;
  TestPacketWriter& operator=(const TestPacketWriter&) = delete;

  // QuicPacketWriter interface
  WriteResult WritePacket(const char* buffer,
                          size_t buf_len,
                          const QuicIpAddress& self_address,
                          const QuicSocketAddress& peer_address,
                          PerPacketOptions* options) override {
    QuicEncryptedPacket packet(buffer, buf_len);
    ++packets_write_attempts_;

    if (packet.length() >= sizeof(final_bytes_of_last_packet_)) {
      final_bytes_of_previous_packet_ = final_bytes_of_last_packet_;
      memcpy(&final_bytes_of_last_packet_, packet.data() + packet.length() - 4,
             sizeof(final_bytes_of_last_packet_));
    }

    if (use_tagging_decrypter_) {
      if (framer_.framer()->version().KnowsWhichDecrypterToUse()) {
        framer_.framer()->InstallDecrypter(ENCRYPTION_INITIAL,
                                           QuicMakeUnique<TaggingDecrypter>());
        framer_.framer()->InstallDecrypter(ENCRYPTION_ZERO_RTT,
                                           QuicMakeUnique<TaggingDecrypter>());
        framer_.framer()->InstallDecrypter(ENCRYPTION_FORWARD_SECURE,
                                           QuicMakeUnique<TaggingDecrypter>());
      } else {
        framer_.framer()->SetDecrypter(ENCRYPTION_INITIAL,
                                       QuicMakeUnique<TaggingDecrypter>());
      }
    } else if (framer_.framer()->version().KnowsWhichDecrypterToUse()) {
      framer_.framer()->InstallDecrypter(
          ENCRYPTION_FORWARD_SECURE,
          QuicMakeUnique<NullDecrypter>(Perspective::IS_SERVER));
    }
    EXPECT_TRUE(framer_.ProcessPacket(packet));
    if (block_on_next_write_) {
      write_blocked_ = true;
      block_on_next_write_ = false;
    }
    if (next_packet_too_large_) {
      next_packet_too_large_ = false;
      return WriteResult(WRITE_STATUS_ERROR, QUIC_EMSGSIZE);
    }
    if (always_get_packet_too_large_) {
      return WriteResult(WRITE_STATUS_ERROR, QUIC_EMSGSIZE);
    }
    if (IsWriteBlocked()) {
      return WriteResult(is_write_blocked_data_buffered_
                             ? WRITE_STATUS_BLOCKED_DATA_BUFFERED
                             : WRITE_STATUS_BLOCKED,
                         0);
    }

    if (ShouldWriteFail()) {
      return WriteResult(WRITE_STATUS_ERROR, 0);
    }

    last_packet_size_ = packet.length();
    last_packet_header_ = framer_.header();

    if (!write_pause_time_delta_.IsZero()) {
      clock_->AdvanceTime(write_pause_time_delta_);
    }
    return WriteResult(WRITE_STATUS_OK, last_packet_size_);
  }

  bool ShouldWriteFail() { return write_should_fail_; }

  bool IsWriteBlocked() const override { return write_blocked_; }

  void SetWriteBlocked() { write_blocked_ = true; }

  void SetWritable() override { write_blocked_ = false; }

  void SetShouldWriteFail() { write_should_fail_ = true; }

  QuicByteCount GetMaxPacketSize(
      const QuicSocketAddress& /*peer_address*/) const override {
    return max_packet_size_;
  }

  bool SupportsReleaseTime() const { return supports_release_time_; }

  bool IsBatchMode() const override { return is_batch_mode_; }

  char* GetNextWriteLocation(const QuicIpAddress& self_address,
                             const QuicSocketAddress& peer_address) override {
    return nullptr;
  }

  WriteResult Flush() override {
    if (block_on_next_flush_) {
      block_on_next_flush_ = false;
      SetWriteBlocked();
      return WriteResult(WRITE_STATUS_BLOCKED, /*errno*/ -1);
    }
    return WriteResult(WRITE_STATUS_OK, 0);
  }

  void BlockOnNextFlush() { block_on_next_flush_ = true; }

  void BlockOnNextWrite() { block_on_next_write_ = true; }

  void SimulateNextPacketTooLarge() { next_packet_too_large_ = true; }

  void AlwaysGetPacketTooLarge() { always_get_packet_too_large_ = true; }

  // Sets the amount of time that the writer should before the actual write.
  void SetWritePauseTimeDelta(QuicTime::Delta delta) {
    write_pause_time_delta_ = delta;
  }

  void SetBatchMode(bool new_value) { is_batch_mode_ = new_value; }

  const QuicPacketHeader& header() { return framer_.header(); }

  size_t frame_count() const { return framer_.num_frames(); }

  const std::vector<QuicAckFrame>& ack_frames() const {
    return framer_.ack_frames();
  }

  const std::vector<QuicStopWaitingFrame>& stop_waiting_frames() const {
    return framer_.stop_waiting_frames();
  }

  const std::vector<QuicConnectionCloseFrame>& connection_close_frames() const {
    return framer_.connection_close_frames();
  }

  const std::vector<QuicRstStreamFrame>& rst_stream_frames() const {
    return framer_.rst_stream_frames();
  }

  const std::vector<std::unique_ptr<QuicStreamFrame>>& stream_frames() const {
    return framer_.stream_frames();
  }

  const std::vector<std::unique_ptr<QuicCryptoFrame>>& crypto_frames() const {
    return framer_.crypto_frames();
  }

  const std::vector<QuicPingFrame>& ping_frames() const {
    return framer_.ping_frames();
  }

  const std::vector<QuicMessageFrame>& message_frames() const {
    return framer_.message_frames();
  }

  const std::vector<QuicWindowUpdateFrame>& window_update_frames() const {
    return framer_.window_update_frames();
  }

  const std::vector<QuicPaddingFrame>& padding_frames() const {
    return framer_.padding_frames();
  }

  const std::vector<QuicPathChallengeFrame>& path_challenge_frames() const {
    return framer_.path_challenge_frames();
  }

  const std::vector<QuicPathResponseFrame>& path_response_frames() const {
    return framer_.path_response_frames();
  }

  size_t last_packet_size() { return last_packet_size_; }

  const QuicPacketHeader& last_packet_header() const {
    return last_packet_header_;
  }

  const QuicVersionNegotiationPacket* version_negotiation_packet() {
    return framer_.version_negotiation_packet();
  }

  void set_is_write_blocked_data_buffered(bool buffered) {
    is_write_blocked_data_buffered_ = buffered;
  }

  void set_perspective(Perspective perspective) {
    // We invert perspective here, because the framer needs to parse packets
    // we send.
    QuicFramerPeer::SetPerspective(framer_.framer(),
                                   InvertPerspective(perspective));
  }

  // final_bytes_of_last_packet_ returns the last four bytes of the previous
  // packet as a little-endian, uint32_t. This is intended to be used with a
  // TaggingEncrypter so that tests can determine which encrypter was used for
  // a given packet.
  uint32_t final_bytes_of_last_packet() { return final_bytes_of_last_packet_; }

  // Returns the final bytes of the second to last packet.
  uint32_t final_bytes_of_previous_packet() {
    return final_bytes_of_previous_packet_;
  }

  void use_tagging_decrypter() { use_tagging_decrypter_ = true; }

  uint32_t packets_write_attempts() { return packets_write_attempts_; }

  void Reset() { framer_.Reset(); }

  void SetSupportedVersions(const ParsedQuicVersionVector& versions) {
    framer_.SetSupportedVersions(versions);
  }

  void set_max_packet_size(QuicByteCount max_packet_size) {
    max_packet_size_ = max_packet_size;
  }

  void set_supports_release_time(bool supports_release_time) {
    supports_release_time_ = supports_release_time;
  }

  SimpleQuicFramer* framer() { return &framer_; }

 private:
  ParsedQuicVersion version_;
  SimpleQuicFramer framer_;
  size_t last_packet_size_;
  QuicPacketHeader last_packet_header_;
  bool write_blocked_;
  bool write_should_fail_;
  bool block_on_next_flush_;
  bool block_on_next_write_;
  bool next_packet_too_large_;
  bool always_get_packet_too_large_;
  bool is_write_blocked_data_buffered_;
  bool is_batch_mode_;
  uint32_t final_bytes_of_last_packet_;
  uint32_t final_bytes_of_previous_packet_;
  bool use_tagging_decrypter_;
  uint32_t packets_write_attempts_;
  MockClock* clock_;
  // If non-zero, the clock will pause during WritePacket for this amount of
  // time.
  QuicTime::Delta write_pause_time_delta_;
  QuicByteCount max_packet_size_;
  bool supports_release_time_;
};

class TestConnection : public QuicConnection {
 public:
  TestConnection(QuicConnectionId connection_id,
                 QuicSocketAddress address,
                 TestConnectionHelper* helper,
                 TestAlarmFactory* alarm_factory,
                 TestPacketWriter* writer,
                 Perspective perspective,
                 ParsedQuicVersion version)
      : QuicConnection(connection_id,
                       address,
                       helper,
                       alarm_factory,
                       writer,
                       /* owns_writer= */ false,
                       perspective,
                       SupportedVersions(version)),
        notifier_(nullptr) {
    writer->set_perspective(perspective);
    SetEncrypter(ENCRYPTION_FORWARD_SECURE,
                 QuicMakeUnique<NullEncrypter>(perspective));
    SetDataProducer(&producer_);
  }
  TestConnection(const TestConnection&) = delete;
  TestConnection& operator=(const TestConnection&) = delete;

  void SendAck() { QuicConnectionPeer::SendAck(this); }

  void SetSendAlgorithm(SendAlgorithmInterface* send_algorithm) {
    QuicConnectionPeer::SetSendAlgorithm(this, send_algorithm);
  }

  void SetLossAlgorithm(LossDetectionInterface* loss_algorithm) {
    QuicConnectionPeer::SetLossAlgorithm(this, loss_algorithm);
  }

  void SendPacket(EncryptionLevel level,
                  uint64_t packet_number,
                  std::unique_ptr<QuicPacket> packet,
                  HasRetransmittableData retransmittable,
                  bool has_ack,
                  bool has_pending_frames) {
    char buffer[kMaxOutgoingPacketSize];
    size_t encrypted_length =
        QuicConnectionPeer::GetFramer(this)->EncryptPayload(
            ENCRYPTION_INITIAL, QuicPacketNumber(packet_number), *packet,
            buffer, kMaxOutgoingPacketSize);
    SerializedPacket serialized_packet(
        QuicPacketNumber(packet_number), PACKET_4BYTE_PACKET_NUMBER, buffer,
        encrypted_length, has_ack, has_pending_frames);
    if (retransmittable == HAS_RETRANSMITTABLE_DATA) {
      serialized_packet.retransmittable_frames.push_back(
          QuicFrame(QuicStreamFrame()));
    }
    OnSerializedPacket(&serialized_packet);
  }

  QuicConsumedData SaveAndSendStreamData(QuicStreamId id,
                                         const struct iovec* iov,
                                         int iov_count,
                                         size_t total_length,
                                         QuicStreamOffset offset,
                                         StreamSendingState state) {
    ScopedPacketFlusher flusher(this, NO_ACK);
    producer_.SaveStreamData(id, iov, iov_count, 0u, total_length);
    if (notifier_ != nullptr) {
      return notifier_->WriteOrBufferData(id, total_length, state);
    }
    return QuicConnection::SendStreamData(id, total_length, offset, state);
  }

  QuicConsumedData SendStreamDataWithString(QuicStreamId id,
                                            QuicStringPiece data,
                                            QuicStreamOffset offset,
                                            StreamSendingState state) {
    ScopedPacketFlusher flusher(this, NO_ACK);
    if (!QuicUtils::IsCryptoStreamId(transport_version(), id) &&
        this->encryption_level() == ENCRYPTION_INITIAL) {
      this->SetDefaultEncryptionLevel(ENCRYPTION_FORWARD_SECURE);
    }
    struct iovec iov;
    MakeIOVector(data, &iov);
    return SaveAndSendStreamData(id, &iov, 1, data.length(), offset, state);
  }

  QuicConsumedData SendApplicationDataAtLevel(EncryptionLevel encryption_level,
                                              QuicStreamId id,
                                              QuicStringPiece data,
                                              QuicStreamOffset offset,
                                              StreamSendingState state) {
    ScopedPacketFlusher flusher(this, NO_ACK);
    DCHECK(encryption_level >= ENCRYPTION_ZERO_RTT);
    SetEncrypter(encryption_level, QuicMakeUnique<TaggingEncrypter>(0x01));
    SetDefaultEncryptionLevel(encryption_level);
    struct iovec iov;
    MakeIOVector(data, &iov);
    return SaveAndSendStreamData(id, &iov, 1, data.length(), offset, state);
  }

  QuicConsumedData SendStreamData3() {
    return SendStreamDataWithString(
        GetNthClientInitiatedStreamId(1, transport_version()), "food", 0,
        NO_FIN);
  }

  QuicConsumedData SendStreamData5() {
    return SendStreamDataWithString(
        GetNthClientInitiatedStreamId(2, transport_version()), "food2", 0,
        NO_FIN);
  }

  // Ensures the connection can write stream data before writing.
  QuicConsumedData EnsureWritableAndSendStreamData5() {
    EXPECT_TRUE(CanWriteStreamData());
    return SendStreamData5();
  }

  // The crypto stream has special semantics so that it is not blocked by a
  // congestion window limitation, and also so that it gets put into a separate
  // packet (so that it is easier to reason about a crypto frame not being
  // split needlessly across packet boundaries).  As a result, we have separate
  // tests for some cases for this stream.
  QuicConsumedData SendCryptoStreamData() {
    QuicStreamOffset offset = 0;
    QuicStringPiece data("chlo");
    return SendCryptoDataWithString(data, offset);
  }

  QuicConsumedData SendCryptoDataWithString(QuicStringPiece data,
                                            QuicStreamOffset offset) {
    if (!QuicVersionUsesCryptoFrames(transport_version())) {
      return SendStreamDataWithString(
          QuicUtils::GetCryptoStreamId(transport_version()), data, offset,
          NO_FIN);
    }
    producer_.SaveCryptoData(ENCRYPTION_INITIAL, offset, data);
    size_t bytes_written;
    if (notifier_) {
      bytes_written =
          notifier_->WriteCryptoData(ENCRYPTION_INITIAL, data.length(), offset);
    } else {
      bytes_written = QuicConnection::SendCryptoData(ENCRYPTION_INITIAL,
                                                     data.length(), offset);
    }
    return QuicConsumedData(bytes_written, /*fin_consumed*/ false);
  }

  void set_version(ParsedQuicVersion version) {
    QuicConnectionPeer::GetFramer(this)->set_version(version);
  }

  void SetSupportedVersions(const ParsedQuicVersionVector& versions) {
    QuicConnectionPeer::GetFramer(this)->SetSupportedVersions(versions);
    QuicConnectionPeer::SetNoVersionNegotiation(this, versions.size() == 1);
    writer()->SetSupportedVersions(versions);
  }

  void set_perspective(Perspective perspective) {
    writer()->set_perspective(perspective);
    QuicConnectionPeer::SetPerspective(this, perspective);
  }

  // Enable path MTU discovery.  Assumes that the test is performed from the
  // client perspective and the higher value of MTU target is used.
  void EnablePathMtuDiscovery(MockSendAlgorithm* send_algorithm) {
    ASSERT_EQ(Perspective::IS_CLIENT, perspective());

    QuicConfig config;
    QuicTagVector connection_options;
    connection_options.push_back(kMTUH);
    config.SetConnectionOptionsToSend(connection_options);
    EXPECT_CALL(*send_algorithm, SetFromConfig(_, _));
    SetFromConfig(config);

    // Normally, the pacing would be disabled in the test, but calling
    // SetFromConfig enables it.  Set nearly-infinite bandwidth to make the
    // pacing algorithm work.
    EXPECT_CALL(*send_algorithm, PacingRate(_))
        .WillRepeatedly(Return(QuicBandwidth::Infinite()));
  }

  TestAlarmFactory::TestAlarm* GetAckAlarm() {
    return reinterpret_cast<TestAlarmFactory::TestAlarm*>(
        QuicConnectionPeer::GetAckAlarm(this));
  }

  TestAlarmFactory::TestAlarm* GetPingAlarm() {
    return reinterpret_cast<TestAlarmFactory::TestAlarm*>(
        QuicConnectionPeer::GetPingAlarm(this));
  }

  TestAlarmFactory::TestAlarm* GetRetransmissionAlarm() {
    return reinterpret_cast<TestAlarmFactory::TestAlarm*>(
        QuicConnectionPeer::GetRetransmissionAlarm(this));
  }

  TestAlarmFactory::TestAlarm* GetSendAlarm() {
    return reinterpret_cast<TestAlarmFactory::TestAlarm*>(
        QuicConnectionPeer::GetSendAlarm(this));
  }

  TestAlarmFactory::TestAlarm* GetTimeoutAlarm() {
    return reinterpret_cast<TestAlarmFactory::TestAlarm*>(
        QuicConnectionPeer::GetTimeoutAlarm(this));
  }

  TestAlarmFactory::TestAlarm* GetMtuDiscoveryAlarm() {
    return reinterpret_cast<TestAlarmFactory::TestAlarm*>(
        QuicConnectionPeer::GetMtuDiscoveryAlarm(this));
  }

  TestAlarmFactory::TestAlarm* GetPathDegradingAlarm() {
    return reinterpret_cast<TestAlarmFactory::TestAlarm*>(
        QuicConnectionPeer::GetPathDegradingAlarm(this));
  }

  TestAlarmFactory::TestAlarm* GetProcessUndecryptablePacketsAlarm() {
    return reinterpret_cast<TestAlarmFactory::TestAlarm*>(
        QuicConnectionPeer::GetProcessUndecryptablePacketsAlarm(this));
  }

  void SetMaxTailLossProbes(size_t max_tail_loss_probes) {
    QuicSentPacketManagerPeer::SetMaxTailLossProbes(
        QuicConnectionPeer::GetSentPacketManager(this), max_tail_loss_probes);
  }

  QuicByteCount GetBytesInFlight() {
    return QuicConnectionPeer::GetSentPacketManager(this)->GetBytesInFlight();
  }

  void set_notifier(SimpleSessionNotifier* notifier) { notifier_ = notifier; }

  void ReturnEffectivePeerAddressForNextPacket(const QuicSocketAddress& addr) {
    next_effective_peer_addr_ = QuicMakeUnique<QuicSocketAddress>(addr);
  }

  SimpleDataProducer* producer() { return &producer_; }

  using QuicConnection::active_effective_peer_migration_type;
  using QuicConnection::IsCurrentPacketConnectivityProbing;
  using QuicConnection::SelectMutualVersion;
  using QuicConnection::SendProbingRetransmissions;
  using QuicConnection::set_defer_send_in_response_to_packets;

 protected:
  QuicSocketAddress GetEffectivePeerAddressFromCurrentPacket() const override {
    if (next_effective_peer_addr_) {
      return *std::move(next_effective_peer_addr_);
    }
    return QuicConnection::GetEffectivePeerAddressFromCurrentPacket();
  }

 private:
  TestPacketWriter* writer() {
    return static_cast<TestPacketWriter*>(QuicConnection::writer());
  }

  SimpleDataProducer producer_;

  SimpleSessionNotifier* notifier_;

  std::unique_ptr<QuicSocketAddress> next_effective_peer_addr_;
};

enum class AckResponse { kDefer, kImmediate };

// Run tests with combinations of {ParsedQuicVersion, AckResponse}.
struct TestParams {
  TestParams(ParsedQuicVersion version,
             AckResponse ack_response,
             bool no_stop_waiting)
      : version(version),
        ack_response(ack_response),
        no_stop_waiting(no_stop_waiting) {}

  friend std::ostream& operator<<(std::ostream& os, const TestParams& p) {
    os << "{ client_version: " << ParsedQuicVersionToString(p.version)
       << " ack_response: "
       << (p.ack_response == AckResponse::kDefer ? "defer" : "immediate")
       << " no_stop_waiting: " << p.no_stop_waiting << " }";
    return os;
  }

  ParsedQuicVersion version;
  AckResponse ack_response;
  bool no_stop_waiting;
};

// Constructs various test permutations.
std::vector<TestParams> GetTestParams() {
  QuicFlagSaver flags;
  SetQuicFlag(FLAGS_quic_supports_tls_handshake, true);
  std::vector<TestParams> params;
  ParsedQuicVersionVector all_supported_versions = AllSupportedVersions();
  for (size_t i = 0; i < all_supported_versions.size(); ++i) {
    for (AckResponse ack_response :
         {AckResponse::kDefer, AckResponse::kImmediate}) {
      for (bool no_stop_waiting : {true, false}) {
        // After version 43, never use STOP_WAITING.
        if (all_supported_versions[i].transport_version <= QUIC_VERSION_43 ||
            no_stop_waiting) {
          params.push_back(TestParams(all_supported_versions[i], ack_response,
                                      no_stop_waiting));
        }
      }
    }
  }
  return params;
}

class QuicConnectionTest : public QuicTestWithParam<TestParams> {
 protected:
  QuicConnectionTest()
      : connection_id_(TestConnectionId()),
        framer_(SupportedVersions(version()),
                QuicTime::Zero(),
                Perspective::IS_CLIENT,
                connection_id_.length()),
        send_algorithm_(new StrictMock<MockSendAlgorithm>),
        loss_algorithm_(new MockLossAlgorithm()),
        helper_(new TestConnectionHelper(&clock_, &random_generator_)),
        alarm_factory_(new TestAlarmFactory()),
        peer_framer_(SupportedVersions(version()),
                     QuicTime::Zero(),
                     Perspective::IS_SERVER,
                     connection_id_.length()),
        peer_creator_(connection_id_,
                      &peer_framer_,
                      /*delegate=*/nullptr),
        writer_(new TestPacketWriter(version(), &clock_)),
        connection_(connection_id_,
                    kPeerAddress,
                    helper_.get(),
                    alarm_factory_.get(),
                    writer_.get(),
                    Perspective::IS_CLIENT,
                    version()),
        creator_(QuicConnectionPeer::GetPacketCreator(&connection_)),
        generator_(QuicConnectionPeer::GetPacketGenerator(&connection_)),
        manager_(QuicConnectionPeer::GetSentPacketManager(&connection_)),
        frame1_(0, false, 0, QuicStringPiece(data1)),
        frame2_(0, false, 3, QuicStringPiece(data2)),
        crypto_frame_(ENCRYPTION_INITIAL, 0, QuicStringPiece(data1)),
        packet_number_length_(PACKET_4BYTE_PACKET_NUMBER),
        connection_id_included_(CONNECTION_ID_PRESENT),
        notifier_(&connection_) {
    SetQuicFlag(FLAGS_quic_supports_tls_handshake, true);
    connection_.set_defer_send_in_response_to_packets(GetParam().ack_response ==
                                                      AckResponse::kDefer);
    for (EncryptionLevel level :
         {ENCRYPTION_ZERO_RTT, ENCRYPTION_FORWARD_SECURE}) {
      peer_creator_.SetEncrypter(
          level, QuicMakeUnique<NullEncrypter>(peer_framer_.perspective()));
    }
    QuicFramerPeer::SetLastSerializedServerConnectionId(
        QuicConnectionPeer::GetFramer(&connection_), connection_id_);
    if (version().transport_version > QUIC_VERSION_43) {
      EXPECT_TRUE(QuicConnectionPeer::GetNoStopWaitingFrames(&connection_));
    } else {
      QuicConnectionPeer::SetNoStopWaitingFrames(&connection_,
                                                 GetParam().no_stop_waiting);
    }
    QuicStreamId stream_id;
    if (QuicVersionUsesCryptoFrames(version().transport_version)) {
      stream_id = QuicUtils::GetFirstBidirectionalStreamId(
          version().transport_version, Perspective::IS_CLIENT);
    } else {
      stream_id = QuicUtils::GetCryptoStreamId(version().transport_version);
    }
    frame1_.stream_id = stream_id;
    frame2_.stream_id = stream_id;
    connection_.set_visitor(&visitor_);
    if (connection_.session_decides_what_to_write()) {
      connection_.SetSessionNotifier(&notifier_);
      connection_.set_notifier(&notifier_);
    }
    connection_.SetSendAlgorithm(send_algorithm_);
    connection_.SetLossAlgorithm(loss_algorithm_.get());
    EXPECT_CALL(*send_algorithm_, CanSend(_)).WillRepeatedly(Return(true));
    EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
        .Times(AnyNumber());
    EXPECT_CALL(*send_algorithm_, GetCongestionWindow())
        .WillRepeatedly(Return(kDefaultTCPMSS));
    EXPECT_CALL(*send_algorithm_, PacingRate(_))
        .WillRepeatedly(Return(QuicBandwidth::Zero()));
    EXPECT_CALL(*send_algorithm_, HasReliableBandwidthEstimate())
        .Times(AnyNumber());
    EXPECT_CALL(*send_algorithm_, BandwidthEstimate())
        .Times(AnyNumber())
        .WillRepeatedly(Return(QuicBandwidth::Zero()));
    EXPECT_CALL(*send_algorithm_, InSlowStart()).Times(AnyNumber());
    EXPECT_CALL(*send_algorithm_, InRecovery()).Times(AnyNumber());
    EXPECT_CALL(*send_algorithm_, OnApplicationLimited(_)).Times(AnyNumber());
    EXPECT_CALL(visitor_, WillingAndAbleToWrite()).Times(AnyNumber());
    EXPECT_CALL(visitor_, HasPendingHandshake()).Times(AnyNumber());
    if (connection_.session_decides_what_to_write()) {
      EXPECT_CALL(visitor_, OnCanWrite())
          .WillRepeatedly(
              Invoke(&notifier_, &SimpleSessionNotifier::OnCanWrite));
    } else {
      EXPECT_CALL(visitor_, OnCanWrite()).Times(AnyNumber());
    }
    EXPECT_CALL(visitor_, ShouldKeepConnectionAlive())
        .WillRepeatedly(Return(false));
    EXPECT_CALL(visitor_, OnCongestionWindowChange(_)).Times(AnyNumber());
    EXPECT_CALL(visitor_, OnConnectivityProbeReceived(_, _)).Times(AnyNumber());
    EXPECT_CALL(visitor_, OnForwardProgressConfirmed()).Times(AnyNumber());

    EXPECT_CALL(*loss_algorithm_, GetLossTimeout())
        .WillRepeatedly(Return(QuicTime::Zero()));
    EXPECT_CALL(*loss_algorithm_, DetectLosses(_, _, _, _, _, _))
        .Times(AnyNumber());

    if (connection_.version().KnowsWhichDecrypterToUse()) {
      connection_.InstallDecrypter(
          ENCRYPTION_FORWARD_SECURE,
          QuicMakeUnique<NullDecrypter>(Perspective::IS_CLIENT));
    }
  }

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

  ParsedQuicVersion version() { return GetParam().version; }

  QuicAckFrame* outgoing_ack() {
    QuicFrame ack_frame = QuicConnectionPeer::GetUpdatedAckFrame(&connection_);
    ack_ = *ack_frame.ack_frame;
    return &ack_;
  }

  QuicStopWaitingFrame* stop_waiting() {
    QuicConnectionPeer::PopulateStopWaitingFrame(&connection_, &stop_waiting_);
    return &stop_waiting_;
  }

  QuicPacketNumber least_unacked() {
    if (writer_->stop_waiting_frames().empty()) {
      return QuicPacketNumber();
    }
    return writer_->stop_waiting_frames()[0].least_unacked;
  }

  void use_tagging_decrypter() { writer_->use_tagging_decrypter(); }

  void SetDecrypter(EncryptionLevel level,
                    std::unique_ptr<QuicDecrypter> decrypter) {
    if (connection_.version().KnowsWhichDecrypterToUse()) {
      connection_.InstallDecrypter(level, std::move(decrypter));
      connection_.RemoveDecrypter(ENCRYPTION_INITIAL);
    } else {
      connection_.SetDecrypter(level, std::move(decrypter));
    }
  }

  void ProcessPacket(uint64_t number) {
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(1);
    ProcessDataPacket(number);
    if (connection_.GetSendAlarm()->IsSet()) {
      connection_.GetSendAlarm()->Fire();
    }
  }

  void ProcessReceivedPacket(const QuicSocketAddress& self_address,
                             const QuicSocketAddress& peer_address,
                             const QuicReceivedPacket& packet) {
    connection_.ProcessUdpPacket(self_address, peer_address, packet);
    if (connection_.GetSendAlarm()->IsSet()) {
      connection_.GetSendAlarm()->Fire();
    }
  }

  void ProcessFramePacket(QuicFrame frame) {
    ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  }

  void ProcessFramePacketWithAddresses(QuicFrame frame,
                                       QuicSocketAddress self_address,
                                       QuicSocketAddress peer_address) {
    QuicFrames frames;
    frames.push_back(QuicFrame(frame));
    QuicPacketCreatorPeer::SetSendVersionInPacket(
        &peer_creator_, connection_.perspective() == Perspective::IS_SERVER);

    char buffer[kMaxOutgoingPacketSize];
    SerializedPacket serialized_packet =
        QuicPacketCreatorPeer::SerializeAllFrames(
            &peer_creator_, frames, buffer, kMaxOutgoingPacketSize);
    connection_.ProcessUdpPacket(
        self_address, peer_address,
        QuicReceivedPacket(serialized_packet.encrypted_buffer,
                           serialized_packet.encrypted_length, clock_.Now()));
    if (connection_.GetSendAlarm()->IsSet()) {
      connection_.GetSendAlarm()->Fire();
    }
  }

  // Bypassing the packet creator is unrealistic, but allows us to process
  // packets the QuicPacketCreator won't allow us to create.
  void ForceProcessFramePacket(QuicFrame frame) {
    QuicFrames frames;
    frames.push_back(QuicFrame(frame));
    bool send_version = connection_.perspective() == Perspective::IS_SERVER;
    if (connection_.version().KnowsWhichDecrypterToUse()) {
      send_version = true;
    }
    QuicPacketCreatorPeer::SetSendVersionInPacket(&peer_creator_, send_version);
    QuicPacketHeader header;
    QuicPacketCreatorPeer::FillPacketHeader(&peer_creator_, &header);
    char encrypted_buffer[kMaxOutgoingPacketSize];
    size_t length = peer_framer_.BuildDataPacket(
        header, frames, encrypted_buffer, kMaxOutgoingPacketSize,
        ENCRYPTION_INITIAL);
    DCHECK_GT(length, 0u);

    const size_t encrypted_length = peer_framer_.EncryptInPlace(
        ENCRYPTION_INITIAL, header.packet_number,
        GetStartOfEncryptedData(peer_framer_.version().transport_version,
                                header),
        length, kMaxOutgoingPacketSize, encrypted_buffer);
    DCHECK_GT(encrypted_length, 0u);

    connection_.ProcessUdpPacket(
        kSelfAddress, kPeerAddress,
        QuicReceivedPacket(encrypted_buffer, encrypted_length, clock_.Now()));
  }

  size_t ProcessFramePacketAtLevel(uint64_t number,
                                   QuicFrame frame,
                                   EncryptionLevel level) {
    QuicPacketHeader header;
    header.destination_connection_id = connection_id_;
    header.packet_number_length = packet_number_length_;
    header.destination_connection_id_included = connection_id_included_;
    if ((peer_framer_.transport_version() > QUIC_VERSION_43 ||
         GetQuicRestartFlag(quic_do_not_override_connection_id)) &&
        peer_framer_.perspective() == Perspective::IS_SERVER) {
      header.destination_connection_id_included = CONNECTION_ID_ABSENT;
    }
    if (level == ENCRYPTION_INITIAL &&
        peer_framer_.version().KnowsWhichDecrypterToUse()) {
      header.version_flag = true;
      header.retry_token_length_length = VARIABLE_LENGTH_INTEGER_LENGTH_1;
      header.length_length = VARIABLE_LENGTH_INTEGER_LENGTH_2;
    }
    if ((GetQuicRestartFlag(quic_do_not_override_connection_id) ||
         (level == ENCRYPTION_INITIAL &&
          peer_framer_.version().KnowsWhichDecrypterToUse())) &&
        header.version_flag &&
        peer_framer_.perspective() == Perspective::IS_SERVER) {
      header.source_connection_id = connection_id_;
      header.source_connection_id_included = CONNECTION_ID_PRESENT;
    }
    header.packet_number = QuicPacketNumber(number);
    QuicFrames frames;
    frames.push_back(frame);
    std::unique_ptr<QuicPacket> packet(ConstructPacket(header, frames));
    // Set the correct encryption level and encrypter on peer_creator and
    // peer_framer, respectively.
    peer_creator_.set_encryption_level(level);
    if (QuicPacketCreatorPeer::GetEncryptionLevel(&peer_creator_) >
        ENCRYPTION_INITIAL) {
      peer_framer_.SetEncrypter(
          QuicPacketCreatorPeer::GetEncryptionLevel(&peer_creator_),
          QuicMakeUnique<TaggingEncrypter>(0x01));
      // Set the corresponding decrypter.
      if (connection_.version().KnowsWhichDecrypterToUse()) {
        connection_.InstallDecrypter(
            QuicPacketCreatorPeer::GetEncryptionLevel(&peer_creator_),
            QuicMakeUnique<StrictTaggingDecrypter>(0x01));
        connection_.RemoveDecrypter(ENCRYPTION_INITIAL);
      } else {
        connection_.SetDecrypter(
            QuicPacketCreatorPeer::GetEncryptionLevel(&peer_creator_),
            QuicMakeUnique<StrictTaggingDecrypter>(0x01));
      }
    }

    char buffer[kMaxOutgoingPacketSize];
    size_t encrypted_length =
        peer_framer_.EncryptPayload(level, QuicPacketNumber(number), *packet,
                                    buffer, kMaxOutgoingPacketSize);
    connection_.ProcessUdpPacket(
        kSelfAddress, kPeerAddress,
        QuicReceivedPacket(buffer, encrypted_length, clock_.Now(), false));
    if (connection_.GetSendAlarm()->IsSet()) {
      connection_.GetSendAlarm()->Fire();
    }
    return encrypted_length;
  }

  size_t ProcessDataPacket(uint64_t number) {
    return ProcessDataPacketAtLevel(number, false, ENCRYPTION_FORWARD_SECURE);
  }

  size_t ProcessDataPacket(QuicPacketNumber packet_number) {
    return ProcessDataPacketAtLevel(packet_number, false,
                                    ENCRYPTION_FORWARD_SECURE);
  }

  size_t ProcessDataPacketAtLevel(QuicPacketNumber packet_number,
                                  bool has_stop_waiting,
                                  EncryptionLevel level) {
    return ProcessDataPacketAtLevel(packet_number.ToUint64(), has_stop_waiting,
                                    level);
  }

  size_t ProcessCryptoPacketAtLevel(uint64_t number, EncryptionLevel level) {
    QuicPacketHeader header = ConstructPacketHeader(1000, ENCRYPTION_INITIAL);
    QuicFrames frames;
    if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
      frames.push_back(QuicFrame(&crypto_frame_));
    } else {
      frames.push_back(QuicFrame(frame1_));
    }
    std::unique_ptr<QuicPacket> packet = ConstructPacket(header, frames);
    char buffer[kMaxOutgoingPacketSize];
    peer_creator_.set_encryption_level(ENCRYPTION_INITIAL);
    size_t encrypted_length =
        peer_framer_.EncryptPayload(ENCRYPTION_INITIAL, QuicPacketNumber(1000),
                                    *packet, buffer, kMaxOutgoingPacketSize);
    connection_.ProcessUdpPacket(
        kSelfAddress, kPeerAddress,
        QuicReceivedPacket(buffer, encrypted_length, clock_.Now(), false));
    if (connection_.GetSendAlarm()->IsSet()) {
      connection_.GetSendAlarm()->Fire();
    }
    return encrypted_length;
  }

  size_t ProcessDataPacketAtLevel(uint64_t number,
                                  bool has_stop_waiting,
                                  EncryptionLevel level) {
    std::unique_ptr<QuicPacket> packet(
        ConstructDataPacket(number, has_stop_waiting, level));
    char buffer[kMaxOutgoingPacketSize];
    peer_creator_.set_encryption_level(level);
    size_t encrypted_length =
        peer_framer_.EncryptPayload(level, QuicPacketNumber(number), *packet,
                                    buffer, kMaxOutgoingPacketSize);
    connection_.ProcessUdpPacket(
        kSelfAddress, kPeerAddress,
        QuicReceivedPacket(buffer, encrypted_length, clock_.Now(), false));
    if (connection_.GetSendAlarm()->IsSet()) {
      connection_.GetSendAlarm()->Fire();
    }
    return encrypted_length;
  }

  void ProcessClosePacket(uint64_t number) {
    std::unique_ptr<QuicPacket> packet(ConstructClosePacket(number));
    char buffer[kMaxOutgoingPacketSize];
    size_t encrypted_length = peer_framer_.EncryptPayload(
        ENCRYPTION_INITIAL, QuicPacketNumber(number), *packet, buffer,
        kMaxOutgoingPacketSize);
    connection_.ProcessUdpPacket(
        kSelfAddress, kPeerAddress,
        QuicReceivedPacket(buffer, encrypted_length, QuicTime::Zero(), false));
  }

  QuicByteCount SendStreamDataToPeer(QuicStreamId id,
                                     QuicStringPiece data,
                                     QuicStreamOffset offset,
                                     StreamSendingState state,
                                     QuicPacketNumber* last_packet) {
    QuicByteCount packet_size;
    EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
        .WillOnce(SaveArg<3>(&packet_size));
    connection_.SendStreamDataWithString(id, data, offset, state);
    if (last_packet != nullptr) {
      *last_packet = creator_->packet_number();
    }
    EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
        .Times(AnyNumber());
    return packet_size;
  }

  void SendAckPacketToPeer() {
    EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(1);
    {
      QuicConnection::ScopedPacketFlusher flusher(&connection_,
                                                  QuicConnection::NO_ACK);
      connection_.SendAck();
    }
    EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
        .Times(AnyNumber());
  }

  void SendRstStream(QuicStreamId id,
                     QuicRstStreamErrorCode error,
                     QuicStreamOffset bytes_written) {
    if (connection_.session_decides_what_to_write()) {
      notifier_.WriteOrBufferRstStream(id, error, bytes_written);
      connection_.OnStreamReset(id, error);
      return;
    }
    std::unique_ptr<QuicRstStreamFrame> rst_stream =
        QuicMakeUnique<QuicRstStreamFrame>(1, id, error, bytes_written);
    if (connection_.SendControlFrame(QuicFrame(rst_stream.get()))) {
      rst_stream.release();
    }
    connection_.OnStreamReset(id, error);
  }

  void SendPing() {
    if (connection_.session_decides_what_to_write()) {
      notifier_.WriteOrBufferPing();
    } else {
      connection_.SendControlFrame(QuicFrame(QuicPingFrame(1)));
    }
  }

  void ProcessAckPacket(uint64_t packet_number, QuicAckFrame* frame) {
    if (packet_number > 1) {
      QuicPacketCreatorPeer::SetPacketNumber(&peer_creator_, packet_number - 1);
    } else {
      QuicPacketCreatorPeer::ClearPacketNumber(&peer_creator_);
    }
    ProcessFramePacket(QuicFrame(frame));
  }

  void ProcessAckPacket(QuicAckFrame* frame) {
    ProcessFramePacket(QuicFrame(frame));
  }

  void ProcessStopWaitingPacket(QuicStopWaitingFrame frame) {
    ProcessFramePacket(QuicFrame(frame));
  }

  size_t ProcessStopWaitingPacketAtLevel(uint64_t number,
                                         QuicStopWaitingFrame frame,
                                         EncryptionLevel level) {
    return ProcessFramePacketAtLevel(number, QuicFrame(frame),
                                     ENCRYPTION_ZERO_RTT);
  }

  void ProcessGoAwayPacket(QuicGoAwayFrame* frame) {
    ProcessFramePacket(QuicFrame(frame));
  }

  bool IsMissing(uint64_t number) {
    return IsAwaitingPacket(*outgoing_ack(), QuicPacketNumber(number),
                            QuicPacketNumber());
  }

  std::unique_ptr<QuicPacket> ConstructPacket(const QuicPacketHeader& header,
                                              const QuicFrames& frames) {
    auto packet = BuildUnsizedDataPacket(&peer_framer_, header, frames);
    EXPECT_NE(nullptr, packet.get());
    return packet;
  }

  QuicPacketHeader ConstructPacketHeader(uint64_t number,
                                         EncryptionLevel level) {
    QuicPacketHeader header;
    if (peer_framer_.transport_version() > QUIC_VERSION_43 &&
        level < ENCRYPTION_FORWARD_SECURE) {
      // Set long header type accordingly.
      header.version_flag = true;
      header.long_packet_type = EncryptionlevelToLongHeaderType(level);
      if (QuicVersionHasLongHeaderLengths(
              peer_framer_.version().transport_version)) {
        header.length_length = VARIABLE_LENGTH_INTEGER_LENGTH_2;
        if (header.long_packet_type == INITIAL) {
          header.retry_token_length_length = VARIABLE_LENGTH_INTEGER_LENGTH_1;
        }
      }
    }
    // Set connection_id to peer's in memory representation as this data packet
    // is created by peer_framer.
    if (GetQuicRestartFlag(quic_do_not_override_connection_id) &&
        peer_framer_.perspective() == Perspective::IS_SERVER) {
      header.source_connection_id = connection_id_;
      header.source_connection_id_included = connection_id_included_;
      header.destination_connection_id_included = CONNECTION_ID_ABSENT;
    } else {
      header.destination_connection_id = connection_id_;
      header.destination_connection_id_included = connection_id_included_;
    }
    if (peer_framer_.transport_version() > QUIC_VERSION_43 &&
        peer_framer_.perspective() == Perspective::IS_SERVER) {
      header.destination_connection_id_included = CONNECTION_ID_ABSENT;
      if (header.version_flag) {
        header.source_connection_id = connection_id_;
        header.source_connection_id_included = CONNECTION_ID_PRESENT;
        if (GetParam().version.handshake_protocol == PROTOCOL_QUIC_CRYPTO &&
            header.long_packet_type == ZERO_RTT_PROTECTED) {
          header.nonce = &kTestDiversificationNonce;
        }
      }
    }
    header.packet_number_length = packet_number_length_;
    header.packet_number = QuicPacketNumber(number);
    return header;
  }

  std::unique_ptr<QuicPacket> ConstructDataPacket(uint64_t number,
                                                  bool has_stop_waiting,
                                                  EncryptionLevel level) {
    QuicPacketHeader header = ConstructPacketHeader(number, level);
    QuicFrames frames;
    frames.push_back(QuicFrame(frame1_));
    if (has_stop_waiting) {
      frames.push_back(QuicFrame(stop_waiting_));
    }
    return ConstructPacket(header, frames);
  }

  OwningSerializedPacketPointer ConstructProbingPacket() {
    if (version().transport_version == QUIC_VERSION_99) {
      QuicPathFrameBuffer payload = {
          {0xde, 0xad, 0xbe, 0xef, 0xba, 0xdc, 0x0f, 0xfe}};
      return QuicPacketCreatorPeer::
          SerializePathChallengeConnectivityProbingPacket(&peer_creator_,
                                                          &payload);
    }
    return QuicPacketCreatorPeer::SerializeConnectivityProbingPacket(
        &peer_creator_);
  }

  std::unique_ptr<QuicPacket> ConstructClosePacket(uint64_t number) {
    QuicPacketHeader header;
    // Set connection_id to peer's in memory representation as this connection
    // close packet is created by peer_framer.
    if (GetQuicRestartFlag(quic_do_not_override_connection_id) &&
        peer_framer_.perspective() == Perspective::IS_SERVER) {
      header.source_connection_id = connection_id_;
      header.destination_connection_id_included = CONNECTION_ID_ABSENT;
      if (peer_framer_.transport_version() <= QUIC_VERSION_43) {
        header.source_connection_id_included = CONNECTION_ID_PRESENT;
      }
    } else {
      header.destination_connection_id = connection_id_;
      if (peer_framer_.transport_version() > QUIC_VERSION_43) {
        header.destination_connection_id_included = CONNECTION_ID_ABSENT;
      }
    }

    header.packet_number = QuicPacketNumber(number);

    QuicConnectionCloseFrame qccf(QUIC_PEER_GOING_AWAY);
    if (peer_framer_.transport_version() == QUIC_VERSION_99) {
      // Default close-type is Google QUIC. If doing IETF/V99 then
      // set close type to be IETF CC/T.
      qccf.close_type = IETF_QUIC_TRANSPORT_CONNECTION_CLOSE;
    }

    QuicFrames frames;
    frames.push_back(QuicFrame(&qccf));
    return ConstructPacket(header, frames);
  }

  QuicTime::Delta DefaultRetransmissionTime() {
    return QuicTime::Delta::FromMilliseconds(kDefaultRetransmissionTimeMs);
  }

  QuicTime::Delta DefaultDelayedAckTime() {
    return QuicTime::Delta::FromMilliseconds(kDefaultDelayedAckTimeMs);
  }

  const QuicStopWaitingFrame InitStopWaitingFrame(uint64_t least_unacked) {
    QuicStopWaitingFrame frame;
    frame.least_unacked = QuicPacketNumber(least_unacked);
    return frame;
  }

  // Construct a ack_frame that acks all packet numbers between 1 and
  // |largest_acked|, except |missing|.
  // REQUIRES: 1 <= |missing| < |largest_acked|
  QuicAckFrame ConstructAckFrame(uint64_t largest_acked, uint64_t missing) {
    return ConstructAckFrame(QuicPacketNumber(largest_acked),
                             QuicPacketNumber(missing));
  }

  QuicAckFrame ConstructAckFrame(QuicPacketNumber largest_acked,
                                 QuicPacketNumber missing) {
    if (missing == QuicPacketNumber(1)) {
      return InitAckFrame({{missing + 1, largest_acked + 1}});
    }
    return InitAckFrame(
        {{QuicPacketNumber(1), missing}, {missing + 1, largest_acked + 1}});
  }

  // Undo nacking a packet within the frame.
  void AckPacket(QuicPacketNumber arrived, QuicAckFrame* frame) {
    EXPECT_FALSE(frame->packets.Contains(arrived));
    frame->packets.Add(arrived);
  }

  void TriggerConnectionClose() {
    // Send an erroneous packet to close the connection.
    EXPECT_CALL(visitor_, OnConnectionClosed(QUIC_INVALID_ACK_DATA, _,
                                             ConnectionCloseSource::FROM_SELF));
    EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
    // Triggers a connection by receiving ACK of unsent packet.
    QuicAckFrame frame = InitAckFrame(10000);
    ProcessAckPacket(1, &frame);

    EXPECT_FALSE(QuicConnectionPeer::GetConnectionClosePacket(&connection_) ==
                 nullptr);
  }

  void BlockOnNextWrite() {
    writer_->BlockOnNextWrite();
    EXPECT_CALL(visitor_, OnWriteBlocked()).Times(AtLeast(1));
  }

  void SimulateNextPacketTooLarge() { writer_->SimulateNextPacketTooLarge(); }

  void AlwaysGetPacketTooLarge() { writer_->AlwaysGetPacketTooLarge(); }

  void SetWritePauseTimeDelta(QuicTime::Delta delta) {
    writer_->SetWritePauseTimeDelta(delta);
  }

  void CongestionBlockWrites() {
    EXPECT_CALL(*send_algorithm_, CanSend(_))
        .WillRepeatedly(testing::Return(false));
  }

  void CongestionUnblockWrites() {
    EXPECT_CALL(*send_algorithm_, CanSend(_))
        .WillRepeatedly(testing::Return(true));
  }

  void set_perspective(Perspective perspective) {
    connection_.set_perspective(perspective);
    if (perspective == Perspective::IS_SERVER) {
      connection_.set_can_truncate_connection_ids(true);
    }
    QuicFramerPeer::SetPerspective(&peer_framer_,
                                   InvertPerspective(perspective));
  }

  void set_packets_between_probes_base(
      const QuicPacketCount packets_between_probes_base) {
    QuicConnectionPeer::SetPacketsBetweenMtuProbes(&connection_,
                                                   packets_between_probes_base);
    QuicConnectionPeer::SetNextMtuProbeAt(
        &connection_, QuicPacketNumber(packets_between_probes_base));
  }

  bool IsDefaultTestConfiguration() {
    TestParams p = GetParam();
    return p.ack_response == AckResponse::kImmediate &&
           p.version == AllSupportedVersions()[0] && p.no_stop_waiting;
  }

  QuicConnectionId connection_id_;
  QuicFramer framer_;

  MockSendAlgorithm* send_algorithm_;
  std::unique_ptr<MockLossAlgorithm> loss_algorithm_;
  MockClock clock_;
  MockRandom random_generator_;
  SimpleBufferAllocator buffer_allocator_;
  std::unique_ptr<TestConnectionHelper> helper_;
  std::unique_ptr<TestAlarmFactory> alarm_factory_;
  QuicFramer peer_framer_;
  QuicPacketCreator peer_creator_;
  std::unique_ptr<TestPacketWriter> writer_;
  TestConnection connection_;
  QuicPacketCreator* creator_;
  QuicPacketGenerator* generator_;
  QuicSentPacketManager* manager_;
  StrictMock<MockQuicConnectionVisitor> visitor_;

  QuicStreamFrame frame1_;
  QuicStreamFrame frame2_;
  QuicCryptoFrame crypto_frame_;
  QuicAckFrame ack_;
  QuicStopWaitingFrame stop_waiting_;
  QuicPacketNumberLength packet_number_length_;
  QuicConnectionIdIncluded connection_id_included_;

  SimpleSessionNotifier notifier_;
};

// Run all end to end tests with all supported versions.
INSTANTIATE_TEST_SUITE_P(SupportedVersion,
                         QuicConnectionTest,
                         ::testing::ValuesIn(GetTestParams()));

TEST_P(QuicConnectionTest, SelfAddressChangeAtClient) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  EXPECT_EQ(Perspective::IS_CLIENT, connection_.perspective());
  EXPECT_TRUE(connection_.connected());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_));
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_));
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  // Cause change in self_address.
  QuicIpAddress host;
  host.FromString("1.1.1.1");
  QuicSocketAddress self_address(host, 123);
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    EXPECT_CALL(visitor_, OnCryptoFrame(_));
  } else {
    EXPECT_CALL(visitor_, OnStreamFrame(_));
  }
  ProcessFramePacketWithAddresses(frame, self_address, kPeerAddress);
  EXPECT_TRUE(connection_.connected());
}

TEST_P(QuicConnectionTest, SelfAddressChangeAtServer) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  set_perspective(Perspective::IS_SERVER);
  QuicPacketCreatorPeer::SetSendVersionInPacket(creator_, false);

  EXPECT_EQ(Perspective::IS_SERVER, connection_.perspective());
  EXPECT_TRUE(connection_.connected());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_));
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_));
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  // Cause change in self_address.
  QuicIpAddress host;
  host.FromString("1.1.1.1");
  QuicSocketAddress self_address(host, 123);
  EXPECT_CALL(visitor_, AllowSelfAddressChange()).WillOnce(Return(false));
  EXPECT_CALL(visitor_, OnConnectionClosed(QUIC_ERROR_MIGRATING_ADDRESS, _, _));
  ProcessFramePacketWithAddresses(frame, self_address, kPeerAddress);
  EXPECT_FALSE(connection_.connected());
}

TEST_P(QuicConnectionTest, AllowSelfAddressChangeToMappedIpv4AddressAtServer) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  set_perspective(Perspective::IS_SERVER);
  QuicPacketCreatorPeer::SetSendVersionInPacket(creator_, false);

  EXPECT_EQ(Perspective::IS_SERVER, connection_.perspective());
  EXPECT_TRUE(connection_.connected());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(3);
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(3);
  }
  QuicIpAddress host;
  host.FromString("1.1.1.1");
  QuicSocketAddress self_address1(host, 443);
  ProcessFramePacketWithAddresses(frame, self_address1, kPeerAddress);
  // Cause self_address change to mapped Ipv4 address.
  QuicIpAddress host2;
  host2.FromString(
      QuicStrCat("::ffff:", connection_.self_address().host().ToString()));
  QuicSocketAddress self_address2(host2, connection_.self_address().port());
  ProcessFramePacketWithAddresses(frame, self_address2, kPeerAddress);
  EXPECT_TRUE(connection_.connected());
  // self_address change back to Ipv4 address.
  ProcessFramePacketWithAddresses(frame, self_address1, kPeerAddress);
  EXPECT_TRUE(connection_.connected());
}

TEST_P(QuicConnectionTest, ClientAddressChangeAndPacketReordered) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_SERVER);
  QuicPacketCreatorPeer::SetSendVersionInPacket(creator_, false);

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is the same as direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  QuicPacketCreatorPeer::SetPacketNumber(&peer_creator_, 5);
  const QuicSocketAddress kNewPeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(),
                        /*port=*/23456);
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kNewPeerAddress);
  EXPECT_EQ(kNewPeerAddress, connection_.peer_address());
  EXPECT_EQ(kNewPeerAddress, connection_.effective_peer_address());

  // Decrease packet number to simulate out-of-order packets.
  QuicPacketCreatorPeer::SetPacketNumber(&peer_creator_, 4);
  // This is an old packet, do not migrate.
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kNewPeerAddress, connection_.peer_address());
  EXPECT_EQ(kNewPeerAddress, connection_.effective_peer_address());
}

TEST_P(QuicConnectionTest, PeerAddressChangeAtServer) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_SERVER);
  QuicPacketCreatorPeer::SetSendVersionInPacket(creator_, false);
  EXPECT_EQ(Perspective::IS_SERVER, connection_.perspective());

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is the same as direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());
  EXPECT_FALSE(connection_.effective_peer_address().IsInitialized());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  // Process another packet with a different peer address on server side will
  // start connection migration.
  const QuicSocketAddress kNewPeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/23456);
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(1);
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kNewPeerAddress);
  EXPECT_EQ(kNewPeerAddress, connection_.peer_address());
  EXPECT_EQ(kNewPeerAddress, connection_.effective_peer_address());
}

TEST_P(QuicConnectionTest, EffectivePeerAddressChangeAtServer) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_SERVER);
  QuicPacketCreatorPeer::SetSendVersionInPacket(creator_, false);
  EXPECT_EQ(Perspective::IS_SERVER, connection_.perspective());

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is different from direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());
  const QuicSocketAddress kEffectivePeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/43210);
  connection_.ReturnEffectivePeerAddressForNextPacket(kEffectivePeerAddress);

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kEffectivePeerAddress, connection_.effective_peer_address());

  // Process another packet with the same direct peer address and different
  // effective peer address on server side will start connection migration.
  const QuicSocketAddress kNewEffectivePeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/54321);
  connection_.ReturnEffectivePeerAddressForNextPacket(kNewEffectivePeerAddress);
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(1);
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kNewEffectivePeerAddress, connection_.effective_peer_address());

  // Process another packet with a different direct peer address and the same
  // effective peer address on server side will not start connection migration.
  const QuicSocketAddress kNewPeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/23456);
  connection_.ReturnEffectivePeerAddressForNextPacket(kNewEffectivePeerAddress);
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  // ack_frame is used to complete the migration started by the last packet, we
  // need to make sure a new migration does not start after the previous one is
  // completed.
  QuicAckFrame ack_frame = InitAckFrame(1);
  EXPECT_CALL(*send_algorithm_, OnCongestionEvent(_, _, _, _, _));
  ProcessFramePacketWithAddresses(QuicFrame(&ack_frame), kSelfAddress,
                                  kNewPeerAddress);
  EXPECT_EQ(kNewPeerAddress, connection_.peer_address());
  EXPECT_EQ(kNewEffectivePeerAddress, connection_.effective_peer_address());

  // Process another packet with different direct peer address and different
  // effective peer address on server side will start connection migration.
  const QuicSocketAddress kNewerEffectivePeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/65432);
  const QuicSocketAddress kFinalPeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/34567);
  connection_.ReturnEffectivePeerAddressForNextPacket(
      kNewerEffectivePeerAddress);
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(1);
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kFinalPeerAddress);
  EXPECT_EQ(kFinalPeerAddress, connection_.peer_address());
  EXPECT_EQ(kNewerEffectivePeerAddress, connection_.effective_peer_address());
  EXPECT_EQ(PORT_CHANGE, connection_.active_effective_peer_migration_type());

  // While the previous migration is ongoing, process another packet with the
  // same direct peer address and different effective peer address on server
  // side will start a new connection migration.
  const QuicSocketAddress kNewestEffectivePeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback4(), /*port=*/65430);
  connection_.ReturnEffectivePeerAddressForNextPacket(
      kNewestEffectivePeerAddress);
  EXPECT_CALL(visitor_, OnConnectionMigration(IPV6_TO_IPV4_CHANGE)).Times(1);
  EXPECT_CALL(*send_algorithm_, OnConnectionMigration()).Times(1);
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kFinalPeerAddress);
  EXPECT_EQ(kFinalPeerAddress, connection_.peer_address());
  EXPECT_EQ(kNewestEffectivePeerAddress, connection_.effective_peer_address());
  EXPECT_EQ(IPV6_TO_IPV4_CHANGE,
            connection_.active_effective_peer_migration_type());
}

TEST_P(QuicConnectionTest, ReceivePaddedPingAtServer) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_SERVER);
  QuicPacketCreatorPeer::SetSendVersionInPacket(creator_, false);
  EXPECT_EQ(Perspective::IS_SERVER, connection_.perspective());

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is the same as direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());
  EXPECT_FALSE(connection_.effective_peer_address().IsInitialized());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  EXPECT_CALL(visitor_, OnConnectivityProbeReceived(_, _)).Times(0);

  // Process a padded PING or PATH CHALLENGE packet with no peer address change
  // on server side will be ignored.
  OwningSerializedPacketPointer probing_packet;
  if (version().transport_version == QUIC_VERSION_99) {
    QuicPathFrameBuffer payload = {
        {0xde, 0xad, 0xbe, 0xef, 0xba, 0xdc, 0x0f, 0xfe}};
    probing_packet =
        QuicPacketCreatorPeer::SerializePathChallengeConnectivityProbingPacket(
            &peer_creator_, &payload);
  } else {
    probing_packet = QuicPacketCreatorPeer::SerializeConnectivityProbingPacket(
        &peer_creator_);
  }
  std::unique_ptr<QuicReceivedPacket> received(ConstructReceivedPacket(
      QuicEncryptedPacket(probing_packet->encrypted_buffer,
                          probing_packet->encrypted_length),
      clock_.Now()));

  uint64_t num_probing_received =
      connection_.GetStats().num_connectivity_probing_received;
  ProcessReceivedPacket(kSelfAddress, kPeerAddress, *received);

  EXPECT_EQ(num_probing_received,
            connection_.GetStats().num_connectivity_probing_received);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());
}

TEST_P(QuicConnectionTest, WriteOutOfOrderQueuedPackets) {
  // EXPECT_QUIC_BUG tests are expensive so only run one instance of them.
  if (!IsDefaultTestConfiguration() ||
      connection_.SupportsMultiplePacketNumberSpaces()) {
    return;
  }

  set_perspective(Perspective::IS_CLIENT);

  BlockOnNextWrite();

  QuicStreamId stream_id = 2;
  connection_.SendStreamDataWithString(stream_id, "foo", 0, NO_FIN);

  EXPECT_EQ(1u, connection_.NumQueuedPackets());

  writer_->SetWritable();
  connection_.SendConnectivityProbingPacket(writer_.get(),
                                            connection_.peer_address());

  EXPECT_CALL(visitor_, OnConnectionClosed(QUIC_INTERNAL_ERROR,
                                           "Packet written out of order.",
                                           ConnectionCloseSource::FROM_SELF));
  EXPECT_QUIC_BUG(connection_.OnCanWrite(),
                  "Attempt to write packet:1 after:2");
  EXPECT_FALSE(connection_.connected());
}

TEST_P(QuicConnectionTest, DiscardQueuedPacketsAfterConnectionClose) {
  // Regression test for b/74073386.
  {
    InSequence seq;
    EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(1);
    EXPECT_CALL(visitor_, OnConnectionClosed(_, _, _)).Times(1);
  }

  set_perspective(Perspective::IS_CLIENT);

  writer_->SimulateNextPacketTooLarge();

  // This packet write should fail, which should cause the connection to close
  // after sending a connection close packet, then the failed packet should be
  // queued.
  connection_.SendStreamDataWithString(/*id=*/2, "foo", 0, NO_FIN);

  EXPECT_FALSE(connection_.connected());
  EXPECT_EQ(1u, connection_.NumQueuedPackets());

  EXPECT_EQ(0u, connection_.GetStats().packets_discarded);
  connection_.OnCanWrite();
  EXPECT_EQ(1u, connection_.GetStats().packets_discarded);
}

TEST_P(QuicConnectionTest, ReceiveConnectivityProbingAtServer) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_SERVER);
  QuicPacketCreatorPeer::SetSendVersionInPacket(creator_, false);
  EXPECT_EQ(Perspective::IS_SERVER, connection_.perspective());

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is the same as direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());
  EXPECT_FALSE(connection_.effective_peer_address().IsInitialized());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  EXPECT_CALL(visitor_, OnConnectivityProbeReceived(_, _)).Times(1);

  // Process a padded PING packet from a new peer address on server side
  // is effectively receiving a connectivity probing.
  const QuicSocketAddress kNewPeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/23456);

  OwningSerializedPacketPointer probing_packet = ConstructProbingPacket();
  std::unique_ptr<QuicReceivedPacket> received(ConstructReceivedPacket(
      QuicEncryptedPacket(probing_packet->encrypted_buffer,
                          probing_packet->encrypted_length),
      clock_.Now()));

  uint64_t num_probing_received =
      connection_.GetStats().num_connectivity_probing_received;
  ProcessReceivedPacket(kSelfAddress, kNewPeerAddress, *received);

  EXPECT_EQ(num_probing_received + 1,
            connection_.GetStats().num_connectivity_probing_received);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  // Process another packet with the old peer address on server side will not
  // start peer migration.
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());
}

TEST_P(QuicConnectionTest, ReceiveReorderedConnectivityProbingAtServer) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_SERVER);
  QuicPacketCreatorPeer::SetSendVersionInPacket(creator_, false);
  EXPECT_EQ(Perspective::IS_SERVER, connection_.perspective());

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is the same as direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());
  EXPECT_FALSE(connection_.effective_peer_address().IsInitialized());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  QuicPacketCreatorPeer::SetPacketNumber(&peer_creator_, 5);
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  // Decrease packet number to simulate out-of-order packets.
  QuicPacketCreatorPeer::SetPacketNumber(&peer_creator_, 4);

  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  EXPECT_CALL(visitor_, OnConnectivityProbeReceived(_, _)).Times(1);

  // Process a padded PING packet from a new peer address on server side
  // is effectively receiving a connectivity probing, even if a newer packet has
  // been received before this one.
  const QuicSocketAddress kNewPeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/23456);

  OwningSerializedPacketPointer probing_packet = ConstructProbingPacket();
  std::unique_ptr<QuicReceivedPacket> received(ConstructReceivedPacket(
      QuicEncryptedPacket(probing_packet->encrypted_buffer,
                          probing_packet->encrypted_length),
      clock_.Now()));

  uint64_t num_probing_received =
      connection_.GetStats().num_connectivity_probing_received;
  ProcessReceivedPacket(kSelfAddress, kNewPeerAddress, *received);

  EXPECT_EQ(num_probing_received + 1,
            connection_.GetStats().num_connectivity_probing_received);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());
}

TEST_P(QuicConnectionTest, MigrateAfterProbingAtServer) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_SERVER);
  QuicPacketCreatorPeer::SetSendVersionInPacket(creator_, false);
  EXPECT_EQ(Perspective::IS_SERVER, connection_.perspective());

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is the same as direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());
  EXPECT_FALSE(connection_.effective_peer_address().IsInitialized());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  EXPECT_CALL(visitor_, OnConnectivityProbeReceived(_, _)).Times(1);

  // Process a padded PING packet from a new peer address on server side
  // is effectively receiving a connectivity probing.
  const QuicSocketAddress kNewPeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/23456);

  OwningSerializedPacketPointer probing_packet = ConstructProbingPacket();
  std::unique_ptr<QuicReceivedPacket> received(ConstructReceivedPacket(
      QuicEncryptedPacket(probing_packet->encrypted_buffer,
                          probing_packet->encrypted_length),
      clock_.Now()));
  ProcessReceivedPacket(kSelfAddress, kNewPeerAddress, *received);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  // Process another non-probing packet with the new peer address on server
  // side will start peer migration.
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(1);

  ProcessFramePacketWithAddresses(frame, kSelfAddress, kNewPeerAddress);
  EXPECT_EQ(kNewPeerAddress, connection_.peer_address());
  EXPECT_EQ(kNewPeerAddress, connection_.effective_peer_address());
}

TEST_P(QuicConnectionTest, ReceivePaddedPingAtClient) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_CLIENT);
  EXPECT_EQ(Perspective::IS_CLIENT, connection_.perspective());

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is the same as direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());
  EXPECT_FALSE(connection_.effective_peer_address().IsInitialized());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  // Client takes all padded PING packet as speculative connectivity
  // probing packet, and reports to visitor.
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  EXPECT_CALL(visitor_, OnConnectivityProbeReceived(_, _)).Times(1);

  OwningSerializedPacketPointer probing_packet = ConstructProbingPacket();
  std::unique_ptr<QuicReceivedPacket> received(ConstructReceivedPacket(
      QuicEncryptedPacket(probing_packet->encrypted_buffer,
                          probing_packet->encrypted_length),
      clock_.Now()));
  uint64_t num_probing_received =
      connection_.GetStats().num_connectivity_probing_received;
  ProcessReceivedPacket(kSelfAddress, kPeerAddress, *received);

  EXPECT_EQ(num_probing_received,
            connection_.GetStats().num_connectivity_probing_received);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());
}

TEST_P(QuicConnectionTest, ReceiveConnectivityProbingAtClient) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_CLIENT);
  EXPECT_EQ(Perspective::IS_CLIENT, connection_.perspective());

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is the same as direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());
  EXPECT_FALSE(connection_.effective_peer_address().IsInitialized());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  // Process a padded PING packet with a different self address on client side
  // is effectively receiving a connectivity probing.
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  EXPECT_CALL(visitor_, OnConnectivityProbeReceived(_, _)).Times(1);

  const QuicSocketAddress kNewSelfAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/23456);

  OwningSerializedPacketPointer probing_packet = ConstructProbingPacket();
  std::unique_ptr<QuicReceivedPacket> received(ConstructReceivedPacket(
      QuicEncryptedPacket(probing_packet->encrypted_buffer,
                          probing_packet->encrypted_length),
      clock_.Now()));
  uint64_t num_probing_received =
      connection_.GetStats().num_connectivity_probing_received;
  ProcessReceivedPacket(kNewSelfAddress, kPeerAddress, *received);

  EXPECT_EQ(num_probing_received + 1,
            connection_.GetStats().num_connectivity_probing_received);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());
}

TEST_P(QuicConnectionTest, PeerAddressChangeAtClient) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  set_perspective(Perspective::IS_CLIENT);
  EXPECT_EQ(Perspective::IS_CLIENT, connection_.perspective());

  // Clear direct_peer_address.
  QuicConnectionPeer::SetDirectPeerAddress(&connection_, QuicSocketAddress());
  // Clear effective_peer_address, it is the same as direct_peer_address for
  // this test.
  QuicConnectionPeer::SetEffectivePeerAddress(&connection_,
                                              QuicSocketAddress());
  EXPECT_FALSE(connection_.effective_peer_address().IsInitialized());

  QuicFrame frame;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frame = QuicFrame(&crypto_frame_);
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(AnyNumber());
  } else {
    frame = QuicFrame(QuicStreamFrame(
        QuicUtils::GetCryptoStreamId(connection_.transport_version()), false,
        0u, QuicStringPiece()));
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(AnyNumber());
  }
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kPeerAddress);
  EXPECT_EQ(kPeerAddress, connection_.peer_address());
  EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());

  // Process another packet with a different peer address on client side will
  // only update peer address.
  const QuicSocketAddress kNewPeerAddress =
      QuicSocketAddress(QuicIpAddress::Loopback6(), /*port=*/23456);
  EXPECT_CALL(visitor_, OnConnectionMigration(PORT_CHANGE)).Times(0);
  ProcessFramePacketWithAddresses(frame, kSelfAddress, kNewPeerAddress);
  EXPECT_EQ(kNewPeerAddress, connection_.peer_address());
  EXPECT_EQ(kNewPeerAddress, connection_.effective_peer_address());
}

TEST_P(QuicConnectionTest, MaxPacketSize) {
  EXPECT_EQ(Perspective::IS_CLIENT, connection_.perspective());
  EXPECT_EQ(1350u, connection_.max_packet_length());
}

TEST_P(QuicConnectionTest, SmallerServerMaxPacketSize) {
  TestConnection connection(TestConnectionId(), kPeerAddress, helper_.get(),
                            alarm_factory_.get(), writer_.get(),
                            Perspective::IS_SERVER, version());
  EXPECT_EQ(Perspective::IS_SERVER, connection.perspective());
  EXPECT_EQ(1000u, connection.max_packet_length());
}

TEST_P(QuicConnectionTest, IncreaseServerMaxPacketSize) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  set_perspective(Perspective::IS_SERVER);
  connection_.SetMaxPacketLength(1000);

  QuicPacketHeader header;
  header.destination_connection_id = connection_id_;
  header.version_flag = true;
  header.packet_number = QuicPacketNumber(1);

  if (QuicVersionHasLongHeaderLengths(
          peer_framer_.version().transport_version)) {
    header.long_packet_type = INITIAL;
    header.retry_token_length_length = VARIABLE_LENGTH_INTEGER_LENGTH_1;
    header.length_length = VARIABLE_LENGTH_INTEGER_LENGTH_2;
  }

  QuicFrames frames;
  QuicPaddingFrame padding;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frames.push_back(QuicFrame(&crypto_frame_));
  } else {
    frames.push_back(QuicFrame(frame1_));
  }
  frames.push_back(QuicFrame(padding));
  std::unique_ptr<QuicPacket> packet(ConstructPacket(header, frames));
  char buffer[kMaxOutgoingPacketSize];
  size_t encrypted_length =
      peer_framer_.EncryptPayload(ENCRYPTION_INITIAL, QuicPacketNumber(12),
                                  *packet, buffer, kMaxOutgoingPacketSize);
  EXPECT_EQ(kMaxOutgoingPacketSize, encrypted_length);

  framer_.set_version(version());
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(1);
  } else {
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(1);
  }
  connection_.ProcessUdpPacket(
      kSelfAddress, kPeerAddress,
      QuicReceivedPacket(buffer, encrypted_length, QuicTime::Zero(), false));

  EXPECT_EQ(kMaxOutgoingPacketSize, connection_.max_packet_length());
}

TEST_P(QuicConnectionTest, IncreaseServerMaxPacketSizeWhileWriterLimited) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  const QuicByteCount lower_max_packet_size = 1240;
  writer_->set_max_packet_size(lower_max_packet_size);
  set_perspective(Perspective::IS_SERVER);
  connection_.SetMaxPacketLength(1000);
  EXPECT_EQ(1000u, connection_.max_packet_length());

  QuicPacketHeader header;
  header.destination_connection_id = connection_id_;
  header.version_flag = true;
  header.packet_number = QuicPacketNumber(1);

  if (QuicVersionHasLongHeaderLengths(
          peer_framer_.version().transport_version)) {
    header.long_packet_type = INITIAL;
    header.retry_token_length_length = VARIABLE_LENGTH_INTEGER_LENGTH_1;
    header.length_length = VARIABLE_LENGTH_INTEGER_LENGTH_2;
  }

  QuicFrames frames;
  QuicPaddingFrame padding;
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    frames.push_back(QuicFrame(&crypto_frame_));
  } else {
    frames.push_back(QuicFrame(frame1_));
  }
  frames.push_back(QuicFrame(padding));
  std::unique_ptr<QuicPacket> packet(ConstructPacket(header, frames));
  char buffer[kMaxOutgoingPacketSize];
  size_t encrypted_length =
      peer_framer_.EncryptPayload(ENCRYPTION_INITIAL, QuicPacketNumber(12),
                                  *packet, buffer, kMaxOutgoingPacketSize);
  EXPECT_EQ(kMaxOutgoingPacketSize, encrypted_length);

  framer_.set_version(version());
  if (QuicVersionUsesCryptoFrames(connection_.transport_version())) {
    EXPECT_CALL(visitor_, OnCryptoFrame(_)).Times(1);
  } else {
    EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(1);
  }
  connection_.ProcessUdpPacket(
      kSelfAddress, kPeerAddress,
      QuicReceivedPacket(buffer, encrypted_length, QuicTime::Zero(), false));

  // Here, the limit imposed by the writer is lower than the size of the packet
  // received, so the writer max packet size is used.
  EXPECT_EQ(lower_max_packet_size, connection_.max_packet_length());
}

TEST_P(QuicConnectionTest, LimitMaxPacketSizeByWriter) {
  const QuicByteCount lower_max_packet_size = 1240;
  writer_->set_max_packet_size(lower_max_packet_size);

  static_assert(lower_max_packet_size < kDefaultMaxPacketSize,
                "Default maximum packet size is too low");
  connection_.SetMaxPacketLength(kDefaultMaxPacketSize);

  EXPECT_EQ(lower_max_packet_size, connection_.max_packet_length());
}

TEST_P(QuicConnectionTest, LimitMaxPacketSizeByWriterForNewConnection) {
  const QuicConnectionId connection_id = TestConnectionId(17);
  const QuicByteCount lower_max_packet_size = 1240;
  writer_->set_max_packet_size(lower_max_packet_size);
  TestConnection connection(connection_id, kPeerAddress, helper_.get(),
                            alarm_factory_.get(), writer_.get(),
                            Perspective::IS_CLIENT, version());
  EXPECT_EQ(Perspective::IS_CLIENT, connection.perspective());
  EXPECT_EQ(lower_max_packet_size, connection.max_packet_length());
}

TEST_P(QuicConnectionTest, PacketsInOrder) {
  if (connection_.SupportsMultiplePacketNumberSpaces()) {
    return;
  }
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  ProcessPacket(1);
  EXPECT_EQ(QuicPacketNumber(1u), LargestAcked(*outgoing_ack()));
  EXPECT_EQ(1u, outgoing_ack()->packets.NumIntervals());

  ProcessPacket(2);
  EXPECT_EQ(QuicPacketNumber(2u), LargestAcked(*outgoing_ack()));
  EXPECT_EQ(1u, outgoing_ack()->packets.NumIntervals());

  ProcessPacket(3);
  EXPECT_EQ(QuicPacketNumber(3u), LargestAcked(*outgoing_ack()));
  EXPECT_EQ(1u, outgoing_ack()->packets.NumIntervals());
}

TEST_P(QuicConnectionTest, PacketsOutOfOrder) {
  if (connection_.SupportsMultiplePacketNumberSpaces()) {
    return;
  }
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  ProcessPacket(3);
  EXPECT_EQ(QuicPacketNumber(3u), LargestAcked(*outgoing_ack()));
  EXPECT_TRUE(IsMissing(2));
  EXPECT_TRUE(IsMissing(1));

  ProcessPacket(2);
  EXPECT_EQ(QuicPacketNumber(3u), LargestAcked(*outgoing_ack()));
  EXPECT_FALSE(IsMissing(2));
  EXPECT_TRUE(IsMissing(1));

  ProcessPacket(1);
  EXPECT_EQ(QuicPacketNumber(3u), LargestAcked(*outgoing_ack()));
  EXPECT_FALSE(IsMissing(2));
  EXPECT_FALSE(IsMissing(1));
}

TEST_P(QuicConnectionTest, DuplicatePacket) {
  if (connection_.SupportsMultiplePacketNumberSpaces()) {
    return;
  }
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  ProcessPacket(3);
  EXPECT_EQ(QuicPacketNumber(3u), LargestAcked(*outgoing_ack()));
  EXPECT_TRUE(IsMissing(2));
  EXPECT_TRUE(IsMissing(1));

  // Send packet 3 again, but do not set the expectation that
  // the visitor OnStreamFrame() will be called.
  ProcessDataPacket(3);
  EXPECT_EQ(QuicPacketNumber(3u), LargestAcked(*outgoing_ack()));
  EXPECT_TRUE(IsMissing(2));
  EXPECT_TRUE(IsMissing(1));
}

TEST_P(QuicConnectionTest, PacketsOutOfOrderWithAdditionsAndLeastAwaiting) {
  if (connection_.SupportsMultiplePacketNumberSpaces()) {
    return;
  }
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  ProcessPacket(3);
  EXPECT_EQ(QuicPacketNumber(3u), LargestAcked(*outgoing_ack()));
  EXPECT_TRUE(IsMissing(2));
  EXPECT_TRUE(IsMissing(1));

  ProcessPacket(2);
  EXPECT_EQ(QuicPacketNumber(3u), LargestAcked(*outgoing_ack()));
  EXPECT_TRUE(IsMissing(1));

  ProcessPacket(5);
  EXPECT_EQ(QuicPacketNumber(5u), LargestAcked(*outgoing_ack()));
  EXPECT_TRUE(IsMissing(1));
  EXPECT_TRUE(IsMissing(4));

  // Pretend at this point the client has gotten acks for 2 and 3 and 1 is a
  // packet the peer will not retransmit.  It indicates this by sending 'least
  // awaiting' is 4.  The connection should then realize 1 will not be
  // retransmitted, and will remove it from the missing list.
  QuicAckFrame frame = InitAckFrame(1);
  EXPECT_CALL(*send_algorithm_, OnCongestionEvent(_, _, _, _, _));
  ProcessAckPacket(6, &frame);

  // Force an ack to be sent.
  SendAckPacketToPeer();
  EXPECT_TRUE(IsMissing(4));
}

TEST_P(QuicConnectionTest, RejectPacketTooFarOut) {
  if (GetQuicReloadableFlag(quic_use_uber_received_packet_manager)) {
    return;
  }
  EXPECT_CALL(visitor_, OnConnectionClosed(QUIC_INVALID_PACKET_HEADER, _,
                                           ConnectionCloseSource::FROM_SELF));

  // Call ProcessDataPacket rather than ProcessPacket, as we should not get a
  // packet call to the visitor.
  if (GetQuicRestartFlag(quic_enable_accept_random_ipn)) {
    ProcessDataPacket(MaxRandomInitialPacketNumber() + 6000);
  } else {
    ProcessDataPacket(6000);
  }
  EXPECT_FALSE(QuicConnectionPeer::GetConnectionClosePacket(&connection_) ==
               nullptr);
}

TEST_P(QuicConnectionTest, RejectUnencryptedStreamData) {
  // EXPECT_QUIC_BUG tests are expensive so only run one instance of them.
  if (!IsDefaultTestConfiguration()) {
    return;
  }

  // Process an unencrypted packet from the non-crypto stream.
  frame1_.stream_id = 3;
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  EXPECT_CALL(visitor_, OnConnectionClosed(QUIC_UNENCRYPTED_STREAM_DATA, _,
                                           ConnectionCloseSource::FROM_SELF));
  EXPECT_QUIC_PEER_BUG(ProcessDataPacketAtLevel(1, false, ENCRYPTION_INITIAL),
                       "");
  EXPECT_FALSE(QuicConnectionPeer::GetConnectionClosePacket(&connection_) ==
               nullptr);
  const std::vector<QuicConnectionCloseFrame>& connection_close_frames =
      writer_->connection_close_frames();
  ASSERT_EQ(1u, connection_close_frames.size());
  EXPECT_EQ(QUIC_UNENCRYPTED_STREAM_DATA,
            connection_close_frames[0].quic_error_code);
}

TEST_P(QuicConnectionTest, OutOfOrderReceiptCausesAckSend) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  ProcessPacket(3);
  if (GetQuicRestartFlag(quic_enable_accept_random_ipn)) {
    // Should not cause an ack.
    EXPECT_EQ(0u, writer_->packets_write_attempts());
  } else {
    // Should ack immediately since we have missing packets.
    EXPECT_EQ(1u, writer_->packets_write_attempts());
  }

  ProcessPacket(2);
  if (GetQuicRestartFlag(quic_enable_accept_random_ipn)) {
    // Should ack immediately, since this fills the last hole.
    EXPECT_EQ(1u, writer_->packets_write_attempts());
  } else {
    // Should ack immediately since we have missing packets.
    EXPECT_EQ(2u, writer_->packets_write_attempts());
  }

  ProcessPacket(1);
  // Should ack immediately, since this fills the last hole.
  if (GetQuicRestartFlag(quic_enable_accept_random_ipn)) {
    EXPECT_EQ(2u, writer_->packets_write_attempts());
  } else {
    EXPECT_EQ(3u, writer_->packets_write_attempts());
  }

  ProcessPacket(4);
  // Should not cause an ack.
  if (GetQuicRestartFlag(quic_enable_accept_random_ipn)) {
    EXPECT_EQ(2u, writer_->packets_write_attempts());
  } else {
    EXPECT_EQ(3u, writer_->packets_write_attempts());
  }
}

TEST_P(QuicConnectionTest, OutOfOrderAckReceiptCausesNoAck) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  SendStreamDataToPeer(1, "foo", 0, NO_FIN, nullptr);
  SendStreamDataToPeer(1, "bar", 3, NO_FIN, nullptr);
  EXPECT_EQ(2u, writer_->packets_write_attempts());

  QuicAckFrame ack1 = InitAckFrame(1);
  QuicAckFrame ack2 = InitAckFrame(2);
  EXPECT_CALL(*send_algorithm_, OnCongestionEvent(true, _, _, _, _));
  ProcessAckPacket(2, &ack2);
  // Should ack immediately since we have missing packets.
  EXPECT_EQ(2u, writer_->packets_write_attempts());

  ProcessAckPacket(1, &ack1);
  // Should not ack an ack filling a missing packet.
  EXPECT_EQ(2u, writer_->packets_write_attempts());
}

TEST_P(QuicConnectionTest, AckReceiptCausesAckSend) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  QuicPacketNumber original, second;

  QuicByteCount packet_size =
      SendStreamDataToPeer(3, "foo", 0, NO_FIN, &original);  // 1st packet.
  SendStreamDataToPeer(3, "bar", 3, NO_FIN, &second);        // 2nd packet.

  QuicAckFrame frame = InitAckFrame({{second, second + 1}});
  // First nack triggers early retransmit.
  LostPacketVector lost_packets;
  lost_packets.push_back(LostPacket(original, kMaxOutgoingPacketSize));
  EXPECT_CALL(*loss_algorithm_, DetectLosses(_, _, _, _, _, _))
      .WillOnce(SetArgPointee<5>(lost_packets));
  EXPECT_CALL(*send_algorithm_, OnCongestionEvent(true, _, _, _, _));
  QuicPacketNumber retransmission;
  // Packet 1 is short header for IETF QUIC because the encryption level
  // switched to ENCRYPTION_FORWARD_SECURE in SendStreamDataToPeer.
  EXPECT_CALL(
      *send_algorithm_,
      OnPacketSent(_, _, _,
                   GetParam().version.transport_version > QUIC_VERSION_43
                       ? packet_size
                       : packet_size - kQuicVersionSize,
                   _))
      .WillOnce(SaveArg<2>(&retransmission));

  ProcessAckPacket(&frame);

  QuicAckFrame frame2 = ConstructAckFrame(retransmission, original);
  EXPECT_CALL(*send_algorithm_, OnCongestionEvent(true, _, _, _, _));
  EXPECT_CALL(*loss_algorithm_, DetectLosses(_, _, _, _, _, _));
  ProcessAckPacket(&frame2);

  // Now if the peer sends an ack which still reports the retransmitted packet
  // as missing, that will bundle an ack with data after two acks in a row
  // indicate the high water mark needs to be raised.
  EXPECT_CALL(*send_algorithm_,
              OnPacketSent(_, _, _, _, HAS_RETRANSMITTABLE_DATA));
  connection_.SendStreamDataWithString(3, "foo", 6, NO_FIN);
  // No ack sent.
  size_t padding_frame_count = writer_->padding_frames().size();
  EXPECT_EQ(padding_frame_count + 1u, writer_->frame_count());
  EXPECT_EQ(1u, writer_->stream_frames().size());

  // No more packet loss for the rest of the test.
  EXPECT_CALL(*loss_algorithm_, DetectLosses(_, _, _, _, _, _))
      .Times(AnyNumber());
  ProcessAckPacket(&frame2);
  EXPECT_CALL(*send_algorithm_,
              OnPacketSent(_, _, _, _, HAS_RETRANSMITTABLE_DATA));
  connection_.SendStreamDataWithString(3, "foo", 9, NO_FIN);
  // Ack bundled.
  if (GetParam().no_stop_waiting) {
    EXPECT_EQ(2u, writer_->frame_count());
  } else {
    EXPECT_EQ(3u, writer_->frame_count());
  }
  EXPECT_EQ(1u, writer_->stream_frames().size());
  EXPECT_FALSE(writer_->ack_frames().empty());

  // But an ack with no missing packets will not send an ack.
  AckPacket(original, &frame2);
  ProcessAckPacket(&frame2);
  ProcessAckPacket(&frame2);
}

TEST_P(QuicConnectionTest, AckSentEveryNthPacket) {
  connection_.set_ack_frequency_before_ack_decimation(3);

  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(39);

  // Expect 13 acks, every 3rd packet.
  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(13);
  // Receives packets 1 - 39.
  for (size_t i = 1; i <= 39; ++i) {
    ProcessDataPacket(i);
  }
}

TEST_P(QuicConnectionTest, AckDecimationReducesAcks) {
  const size_t kMinRttMs = 40;
  RttStats* rtt_stats = const_cast<RttStats*>(manager_->GetRttStats());
  rtt_stats->UpdateRtt(QuicTime::Delta::FromMilliseconds(kMinRttMs),
                       QuicTime::Delta::Zero(), QuicTime::Zero());
  EXPECT_CALL(visitor_, OnAckNeedsRetransmittableFrame()).Times(AnyNumber());

  QuicConnectionPeer::SetAckMode(&connection_, ACK_DECIMATION_WITH_REORDERING);

  // Start ack decimation from 10th packet.
  connection_.set_min_received_before_ack_decimation(10);

  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(30);

  // Expect 6 acks: 5 acks between packets 1-10, and ack at 20.
  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(6);
  // Receives packets 1 - 29.
  for (size_t i = 1; i <= 29; ++i) {
    ProcessDataPacket(i);
  }

  // We now receive the 30th packet, and so we send an ack.
  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(1);
  ProcessDataPacket(30);
}

TEST_P(QuicConnectionTest, AckNeedsRetransmittableFrames) {
  connection_.SetDefaultEncryptionLevel(ENCRYPTION_FORWARD_SECURE);
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
  EXPECT_CALL(visitor_, OnStreamFrame(_)).Times(99);

  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(19);
  // Receives packets 1 - 39.
  for (size_t i = 1; i <= 39; ++i) {
    ProcessDataPacket(i);
  }
  // Receiving Packet 40 causes 20th ack to send. Session is informed and adds
  // WINDOW_UPDATE.
  EXPECT_CALL(visitor_, OnAckNeedsRetransmittableFrame())
      .WillOnce(Invoke([this]() {
        connection_.SendControlFrame(
            QuicFrame(new QuicWindowUpdateFrame(1, 0, 0)));
      }));
  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(1);
  EXPECT_EQ(0u, writer_->window_update_frames().size());
  ProcessDataPacket(40);
  EXPECT_EQ(1u, writer_->window_update_frames().size());

  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(9);
  // Receives packets 41 - 59.
  for (size_t i = 41; i <= 59; ++i) {
    ProcessDataPacket(i);
  }
  // Send a packet containing stream frame.
  SendStreamDataToPeer(
      QuicUtils::GetFirstBidirectionalStreamId(
          connection_.version().transport_version, Perspective::IS_CLIENT),
      "bar", 0, NO_FIN, nullptr);

  // Session will not be informed until receiving another 20 packets.
  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(19);
  for (size_t i = 60; i <= 98; ++i) {
    ProcessDataPacket(i);
    EXPECT_EQ(0u, writer_->window_update_frames().size());
  }
  // Session does not add a retransmittable frame.
  EXPECT_CALL(visitor_, OnAckNeedsRetransmittableFrame())
      .WillOnce(Invoke([this]() {
        connection_.SendControlFrame(QuicFrame(QuicPingFrame(1)));
      }));
  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _)).Times(1);
  EXPECT_EQ(0u, writer_->ping_frames().size());
  ProcessDataPacket(99);
  EXPECT_EQ(0u, writer_->window_update_frames().size());
  // A ping frame will be added.
  EXPECT_EQ(1u, writer_->ping_frames().size());
}

TEST_P(QuicConnectionTest, LeastUnackedLower) {
  if (GetParam().version.transport_version > QUIC_VERSION_43 ||
      connection_.SupportsMultiplePacketNumberSpaces()) {
    return;
  }
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  SendStreamDataToPeer(1, "foo", 0, NO_FIN, nullptr);
  SendStreamDataToPeer(1, "bar", 3, NO_FIN, nullptr);
  SendStreamDataToPeer(1, "eep", 6, NO_FIN, nullptr);

  // Start out saying the least unacked is 2.
  QuicPacketCreatorPeer::SetPacketNumber(&peer_creator_, 5);
  ProcessStopWaitingPacket(InitStopWaitingFrame(2));

  // Change it to 1, but lower the packet number to fake out-of-order packets.
  // This should be fine.
  QuicPacketCreatorPeer::SetPacketNumber(&peer_creator_, 1);
  // The scheduler will not process out of order acks, but all packet processing
  // causes the connection to try to write.
  if (!GetParam().no_stop_waiting) {
    EXPECT_CALL(visitor_, OnCanWrite());
  }
  ProcessStopWaitingPacket(InitStopWaitingFrame(1));

  // Now claim it's one, but set the ordering so it was sent "after" the first
  // one.  This should cause a connection error.
  QuicPacketCreatorPeer::SetPacketNumber(&peer_creator_, 7);
  if (!GetParam().no_stop_waiting) {
    EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _));
    EXPECT_CALL(visitor_, OnConnectionClosed(QUIC_INVALID_STOP_WAITING_DATA, _,
                                             ConnectionCloseSource::FROM_SELF));
  }
  ProcessStopWaitingPacket(InitStopWaitingFrame(1));
}

TEST_P(QuicConnectionTest, TooManySentPackets) {
  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));

  QuicPacketCount max_tracked_packets = 50;
  QuicConnectionPeer::SetMaxTrackedPackets(&connection_, max_tracked_packets);

  const int num_packets = max_tracked_packets + 5;

  for (int i = 0; i < num_packets; ++i) {
    SendStreamDataToPeer(1, "foo", 3 * i, NO_FIN, nullptr);
  }

  // Ack packet 1, which leaves more than the limit outstanding.
  EXPECT_CALL(*send_algorithm_, OnCongestionEvent(true, _, _, _, _));
  EXPECT_CALL(visitor_,
              OnConnectionClosed(QUIC_TOO_MANY_OUTSTANDING_SENT_PACKETS, _,
                                 ConnectionCloseSource::FROM_SELF));

  // Nack the first packet and ack the rest, leaving a huge gap.