Landing Recent QUIC changes until 01/28/2016 18:41 UTC

net/quic/congestion_control/tcp_loss_algorithm_test.cc

-// Copyright 2014 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/quic/congestion_control/tcp_loss_algorithm.h"
-
-#include <algorithm>
-
-#include "base/logging.h"
-#include "base/stl_util.h"
-#include "net/quic/congestion_control/rtt_stats.h"
-#include "net/quic/quic_unacked_packet_map.h"
-#include "net/quic/test_tools/mock_clock.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-using std::vector;
-
-namespace net {
-namespace test {
-namespace {
-
-// Default packet length.
-const uint32_t kDefaultLength = 1000;
-
-class TcpLossAlgorithmTest : public ::testing::Test {
- protected:
-  TcpLossAlgorithmTest() {
-    rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(100),
-                         QuicTime::Delta::Zero(), clock_.Now());
-  }
-
-  ~TcpLossAlgorithmTest() override { STLDeleteElements(&packets_); }
-
-  void SendDataPacket(QuicPacketNumber packet_number) {
-    packets_.push_back(new QuicEncryptedPacket(nullptr, kDefaultLength));
-    QuicFrames* frames = new QuicFrames();
-    QuicStreamFrame* frame = new QuicStreamFrame();
-    frame->stream_id = kHeadersStreamId;
-    frames->push_back(QuicFrame(frame));
-    SerializedPacket packet(kDefaultPathId, packet_number,
-                            PACKET_1BYTE_PACKET_NUMBER, packets_.back(), 0,
-                            frames, false, false);
-    unacked_packets_.AddSentPacket(&packet, 0, NOT_RETRANSMISSION, clock_.Now(),
-                                   1000, true);
-  }
-
-  void VerifyLosses(QuicPacketNumber largest_observed,
-                    QuicPacketNumber* losses_expected,
-                    size_t num_losses) {
-    PacketNumberSet lost_packets = loss_algorithm_.DetectLostPackets(
-        unacked_packets_, clock_.Now(), largest_observed, rtt_stats_);
-    EXPECT_EQ(num_losses, lost_packets.size());
-    for (size_t i = 0; i < num_losses; ++i) {
-      EXPECT_TRUE(ContainsKey(lost_packets, losses_expected[i]));
-    }
-  }
-
-  vector<QuicEncryptedPacket*> packets_;
-  QuicUnackedPacketMap unacked_packets_;
-  TCPLossAlgorithm loss_algorithm_;
-  RttStats rtt_stats_;
-  MockClock clock_;
-};
-
-TEST_F(TcpLossAlgorithmTest, NackRetransmit1Packet) {
-  const size_t kNumSentPackets = 5;
-  // Transmit 5 packets.
-  for (size_t i = 1; i <= kNumSentPackets; ++i) {
-    SendDataPacket(i);
-  }
-  // No loss on one ack.
-  unacked_packets_.RemoveFromInFlight(2);
-  unacked_packets_.NackPacket(1, 1);
-  VerifyLosses(2, nullptr, 0);
-  // No loss on two acks.
-  unacked_packets_.RemoveFromInFlight(3);
-  unacked_packets_.NackPacket(1, 2);
-  VerifyLosses(3, nullptr, 0);
-  // Loss on three acks.
-  unacked_packets_.RemoveFromInFlight(4);
-  unacked_packets_.NackPacket(1, 3);
-  QuicPacketNumber lost[] = {1};
-  VerifyLosses(4, lost, arraysize(lost));
-  EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
-}
-
-// A stretch ack is an ack that covers more than 1 packet of previously
-// unacknowledged data.
-TEST_F(TcpLossAlgorithmTest, NackRetransmit1PacketWith1StretchAck) {
-  const size_t kNumSentPackets = 10;
-  // Transmit 10 packets.
-  for (size_t i = 1; i <= kNumSentPackets; ++i) {
-    SendDataPacket(i);
-  }
-
-  // Nack the first packet 3 times in a single StretchAck.
-  unacked_packets_.NackPacket(1, 3);
-  unacked_packets_.RemoveFromInFlight(2);
-  unacked_packets_.RemoveFromInFlight(3);
-  unacked_packets_.RemoveFromInFlight(4);
-  QuicPacketNumber lost[] = {1};
-  VerifyLosses(4, lost, arraysize(lost));
-  EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
-}
-
-// Ack a packet 3 packets ahead, causing a retransmit.
-TEST_F(TcpLossAlgorithmTest, NackRetransmit1PacketSingleAck) {
-  const size_t kNumSentPackets = 10;
-  // Transmit 10 packets.
-  for (size_t i = 1; i <= kNumSentPackets; ++i) {
-    SendDataPacket(i);
-  }
-
-  // Nack the first packet 3 times in an AckFrame with three missing packets.
-  unacked_packets_.NackPacket(1, 3);
-  unacked_packets_.NackPacket(2, 2);
-  unacked_packets_.NackPacket(3, 1);
-  unacked_packets_.RemoveFromInFlight(4);
-  QuicPacketNumber lost[] = {1};
-  VerifyLosses(4, lost, arraysize(lost));
-  EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
-}
-
-TEST_F(TcpLossAlgorithmTest, EarlyRetransmit1Packet) {
-  const size_t kNumSentPackets = 2;
-  // Transmit 2 packets.
-  for (size_t i = 1; i <= kNumSentPackets; ++i) {
-    SendDataPacket(i);
-  }
-  // Early retransmit when the final packet gets acked and the first is nacked.
-  unacked_packets_.RemoveFromInFlight(2);
-  unacked_packets_.NackPacket(1, 1);
-  VerifyLosses(2, nullptr, 0);
-  EXPECT_EQ(clock_.Now().Add(rtt_stats_.smoothed_rtt().Multiply(1.25)),
-            loss_algorithm_.GetLossTimeout());
-
-  clock_.AdvanceTime(rtt_stats_.latest_rtt().Multiply(1.25));
-  QuicPacketNumber lost[] = {1};
-  VerifyLosses(2, lost, arraysize(lost));
-  EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
-}
-
-TEST_F(TcpLossAlgorithmTest, EarlyRetransmitAllPackets) {
-  const size_t kNumSentPackets = 5;
-  for (size_t i = 1; i <= kNumSentPackets; ++i) {
-    SendDataPacket(i);
-    // Advance the time 1/4 RTT between 3 and 4.
-    if (i == 3) {
-      clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.25));
-    }
-  }
-
-  // Early retransmit when the final packet gets acked and 1.25 RTTs have
-  // elapsed since the packets were sent.
-  unacked_packets_.RemoveFromInFlight(kNumSentPackets);
-  // This simulates a single ack following multiple missing packets with FACK.
-  for (size_t i = 1; i < kNumSentPackets; ++i) {
-    unacked_packets_.NackPacket(i, static_cast<uint16_t>(kNumSentPackets - i));
-  }
-  QuicPacketNumber lost[] = {1, 2};
-  VerifyLosses(kNumSentPackets, lost, arraysize(lost));
-  // The time has already advanced 1/4 an RTT, so ensure the timeout is set
-  // 1.25 RTTs after the earliest pending packet(3), not the last(4).
-  EXPECT_EQ(clock_.Now().Add(rtt_stats_.smoothed_rtt()),
-            loss_algorithm_.GetLossTimeout());
-
-  clock_.AdvanceTime(rtt_stats_.smoothed_rtt());
-  QuicPacketNumber lost2[] = {1, 2, 3};
-  VerifyLosses(kNumSentPackets, lost2, arraysize(lost2));
-  EXPECT_EQ(clock_.Now().Add(rtt_stats_.smoothed_rtt().Multiply(0.25)),
-            loss_algorithm_.GetLossTimeout());
-  clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.25));
-  QuicPacketNumber lost3[] = {1, 2, 3, 4};
-  VerifyLosses(kNumSentPackets, lost3, arraysize(lost3));
-  EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
-}
-
-TEST_F(TcpLossAlgorithmTest, DontEarlyRetransmitNeuteredPacket) {
-  const size_t kNumSentPackets = 2;
-  // Transmit 2 packets.
-  for (size_t i = 1; i <= kNumSentPackets; ++i) {
-    SendDataPacket(i);
-  }
-  // Neuter packet 1.
-  unacked_packets_.RemoveRetransmittability(1);
-
-  // Early retransmit when the final packet gets acked and the first is nacked.
-  unacked_packets_.IncreaseLargestObserved(2);
-  unacked_packets_.RemoveFromInFlight(2);
-  unacked_packets_.NackPacket(1, 1);
-  VerifyLosses(2, nullptr, 0);
-  EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
-}
-
-TEST_F(TcpLossAlgorithmTest, AlwaysLosePacketSent1RTTEarlier) {
-  // Transmit 1 packet and then wait an rtt plus 1ms.
-  SendDataPacket(1);
-  clock_.AdvanceTime(
-      rtt_stats_.smoothed_rtt().Add(QuicTime::Delta::FromMilliseconds(1)));
-
-  // Transmit 2 packets.
-  SendDataPacket(2);
-  SendDataPacket(3);
-
-  // Wait another RTT and ack 2.
-  clock_.AdvanceTime(rtt_stats_.smoothed_rtt());
-  unacked_packets_.IncreaseLargestObserved(2);
-  unacked_packets_.RemoveFromInFlight(2);
-  unacked_packets_.NackPacket(1, 1);
-  QuicPacketNumber lost[] = {1};
-  VerifyLosses(2, lost, arraysize(lost));
-}
-
-}  // namespace
-}  // namespace test
-}  // namespace net