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| 1 // Copyright 2014 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include <algorithm> | |
| 6 | |
| 7 #include "base/logging.h" | |
| 8 #include "base/stl_util.h" | |
| 9 #include "net/quic/congestion_control/rtt_stats.h" | |
| 10 #include "net/quic/congestion_control/tcp_loss_algorithm.h" | |
| 11 #include "net/quic/quic_unacked_packet_map.h" | |
| 12 #include "net/quic/test_tools/mock_clock.h" | |
| 13 #include "testing/gtest/include/gtest/gtest.h" | |
| 14 | |
| 15 using std::vector; | |
| 16 | |
| 17 namespace net { | |
| 18 namespace test { | |
| 19 namespace { | |
| 20 | |
| 21 // Default packet length. | |
| 22 const uint32 kDefaultLength = 1000; | |
| 23 | |
| 24 class TcpLossAlgorithmTest : public ::testing::Test { | |
| 25 protected: | |
| 26 TcpLossAlgorithmTest() | |
| 27 : unacked_packets_() { | |
| 28 rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(100), | |
| 29 QuicTime::Delta::Zero(), | |
| 30 clock_.Now()); | |
| 31 } | |
| 32 | |
| 33 ~TcpLossAlgorithmTest() override { | |
| 34 STLDeleteElements(&packets_); | |
| 35 } | |
| 36 | |
| 37 void SendDataPacket(QuicPacketSequenceNumber sequence_number) { | |
| 38 packets_.push_back(new QuicEncryptedPacket(nullptr, kDefaultLength)); | |
| 39 SerializedPacket packet(sequence_number, PACKET_1BYTE_SEQUENCE_NUMBER, | |
| 40 packets_.back(), 0, new RetransmittableFrames()); | |
| 41 unacked_packets_.AddSentPacket(packet, 0, NOT_RETRANSMISSION, clock_.Now(), | |
| 42 1000, true); | |
| 43 } | |
| 44 | |
| 45 void VerifyLosses(QuicPacketSequenceNumber largest_observed, | |
| 46 QuicPacketSequenceNumber* losses_expected, | |
| 47 size_t num_losses) { | |
| 48 SequenceNumberSet lost_packets = | |
| 49 loss_algorithm_.DetectLostPackets( | |
| 50 unacked_packets_, clock_.Now(), largest_observed, rtt_stats_); | |
| 51 EXPECT_EQ(num_losses, lost_packets.size()); | |
| 52 for (size_t i = 0; i < num_losses; ++i) { | |
| 53 EXPECT_TRUE(ContainsKey(lost_packets, losses_expected[i])); | |
| 54 } | |
| 55 } | |
| 56 | |
| 57 vector<QuicEncryptedPacket*> packets_; | |
| 58 QuicUnackedPacketMap unacked_packets_; | |
| 59 TCPLossAlgorithm loss_algorithm_; | |
| 60 RttStats rtt_stats_; | |
| 61 MockClock clock_; | |
| 62 }; | |
| 63 | |
| 64 TEST_F(TcpLossAlgorithmTest, NackRetransmit1Packet) { | |
| 65 const size_t kNumSentPackets = 5; | |
| 66 // Transmit 5 packets. | |
| 67 for (size_t i = 1; i <= kNumSentPackets; ++i) { | |
| 68 SendDataPacket(i); | |
| 69 } | |
| 70 // No loss on one ack. | |
| 71 unacked_packets_.RemoveFromInFlight(2); | |
| 72 unacked_packets_.NackPacket(1, 1); | |
| 73 VerifyLosses(2, nullptr, 0); | |
| 74 // No loss on two acks. | |
| 75 unacked_packets_.RemoveFromInFlight(3); | |
| 76 unacked_packets_.NackPacket(1, 2); | |
| 77 VerifyLosses(3, nullptr, 0); | |
| 78 // Loss on three acks. | |
| 79 unacked_packets_.RemoveFromInFlight(4); | |
| 80 unacked_packets_.NackPacket(1, 3); | |
| 81 QuicPacketSequenceNumber lost[] = {1}; | |
| 82 VerifyLosses(4, lost, arraysize(lost)); | |
| 83 EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout()); | |
| 84 } | |
| 85 | |
| 86 // A stretch ack is an ack that covers more than 1 packet of previously | |
| 87 // unacknowledged data. | |
| 88 TEST_F(TcpLossAlgorithmTest, NackRetransmit1PacketWith1StretchAck) { | |
| 89 const size_t kNumSentPackets = 10; | |
| 90 // Transmit 10 packets. | |
| 91 for (size_t i = 1; i <= kNumSentPackets; ++i) { | |
| 92 SendDataPacket(i); | |
| 93 } | |
| 94 | |
| 95 // Nack the first packet 3 times in a single StretchAck. | |
| 96 unacked_packets_.NackPacket(1, 3); | |
| 97 unacked_packets_.RemoveFromInFlight(2); | |
| 98 unacked_packets_.RemoveFromInFlight(3); | |
| 99 unacked_packets_.RemoveFromInFlight(4); | |
| 100 QuicPacketSequenceNumber lost[] = { 1 }; | |
| 101 VerifyLosses(4, lost, arraysize(lost)); | |
| 102 EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout()); | |
| 103 } | |
| 104 | |
| 105 // Ack a packet 3 packets ahead, causing a retransmit. | |
| 106 TEST_F(TcpLossAlgorithmTest, NackRetransmit1PacketSingleAck) { | |
| 107 const size_t kNumSentPackets = 10; | |
| 108 // Transmit 10 packets. | |
| 109 for (size_t i = 1; i <= kNumSentPackets; ++i) { | |
| 110 SendDataPacket(i); | |
| 111 } | |
| 112 | |
| 113 // Nack the first packet 3 times in an AckFrame with three missing packets. | |
| 114 unacked_packets_.NackPacket(1, 3); | |
| 115 unacked_packets_.NackPacket(2, 2); | |
| 116 unacked_packets_.NackPacket(3, 1); | |
| 117 unacked_packets_.RemoveFromInFlight(4); | |
| 118 QuicPacketSequenceNumber lost[] = { 1 }; | |
| 119 VerifyLosses(4, lost, arraysize(lost)); | |
| 120 EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout()); | |
| 121 } | |
| 122 | |
| 123 TEST_F(TcpLossAlgorithmTest, EarlyRetransmit1Packet) { | |
| 124 const size_t kNumSentPackets = 2; | |
| 125 // Transmit 2 packets. | |
| 126 for (size_t i = 1; i <= kNumSentPackets; ++i) { | |
| 127 SendDataPacket(i); | |
| 128 } | |
| 129 // Early retransmit when the final packet gets acked and the first is nacked. | |
| 130 unacked_packets_.RemoveFromInFlight(2); | |
| 131 unacked_packets_.NackPacket(1, 1); | |
| 132 VerifyLosses(2, nullptr, 0); | |
| 133 EXPECT_EQ(clock_.Now().Add(rtt_stats_.smoothed_rtt().Multiply(1.25)), | |
| 134 loss_algorithm_.GetLossTimeout()); | |
| 135 | |
| 136 clock_.AdvanceTime(rtt_stats_.latest_rtt().Multiply(1.25)); | |
| 137 QuicPacketSequenceNumber lost[] = { 1 }; | |
| 138 VerifyLosses(2, lost, arraysize(lost)); | |
| 139 EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout()); | |
| 140 } | |
| 141 | |
| 142 TEST_F(TcpLossAlgorithmTest, EarlyRetransmitAllPackets) { | |
| 143 const size_t kNumSentPackets = 5; | |
| 144 for (size_t i = 1; i <= kNumSentPackets; ++i) { | |
| 145 SendDataPacket(i); | |
| 146 // Advance the time 1/4 RTT between 3 and 4. | |
| 147 if (i == 3) { | |
| 148 clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.25)); | |
| 149 } | |
| 150 } | |
| 151 | |
| 152 // Early retransmit when the final packet gets acked and 1.25 RTTs have | |
| 153 // elapsed since the packets were sent. | |
| 154 unacked_packets_.RemoveFromInFlight(kNumSentPackets); | |
| 155 // This simulates a single ack following multiple missing packets with FACK. | |
| 156 for (size_t i = 1; i < kNumSentPackets; ++i) { | |
| 157 unacked_packets_.NackPacket(i, kNumSentPackets - i); | |
| 158 } | |
| 159 QuicPacketSequenceNumber lost[] = { 1, 2 }; | |
| 160 VerifyLosses(kNumSentPackets, lost, arraysize(lost)); | |
| 161 // The time has already advanced 1/4 an RTT, so ensure the timeout is set | |
| 162 // 1.25 RTTs after the earliest pending packet(3), not the last(4). | |
| 163 EXPECT_EQ(clock_.Now().Add(rtt_stats_.smoothed_rtt()), | |
| 164 loss_algorithm_.GetLossTimeout()); | |
| 165 | |
| 166 clock_.AdvanceTime(rtt_stats_.smoothed_rtt()); | |
| 167 QuicPacketSequenceNumber lost2[] = { 1, 2, 3 }; | |
| 168 VerifyLosses(kNumSentPackets, lost2, arraysize(lost2)); | |
| 169 EXPECT_EQ(clock_.Now().Add(rtt_stats_.smoothed_rtt().Multiply(0.25)), | |
| 170 loss_algorithm_.GetLossTimeout()); | |
| 171 clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.25)); | |
| 172 QuicPacketSequenceNumber lost3[] = { 1, 2, 3, 4 }; | |
| 173 VerifyLosses(kNumSentPackets, lost3, arraysize(lost3)); | |
| 174 EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout()); | |
| 175 } | |
| 176 | |
| 177 TEST_F(TcpLossAlgorithmTest, DontEarlyRetransmitNeuteredPacket) { | |
| 178 const size_t kNumSentPackets = 2; | |
| 179 // Transmit 2 packets. | |
| 180 for (size_t i = 1; i <= kNumSentPackets; ++i) { | |
| 181 SendDataPacket(i); | |
| 182 } | |
| 183 // Neuter packet 1. | |
| 184 unacked_packets_.RemoveRetransmittability(1); | |
| 185 | |
| 186 // Early retransmit when the final packet gets acked and the first is nacked. | |
| 187 unacked_packets_.IncreaseLargestObserved(2); | |
| 188 unacked_packets_.RemoveFromInFlight(2); | |
| 189 unacked_packets_.NackPacket(1, 1); | |
| 190 VerifyLosses(2, nullptr, 0); | |
| 191 EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout()); | |
| 192 } | |
| 193 | |
| 194 TEST_F(TcpLossAlgorithmTest, AlwaysLosePacketSent1RTTEarlier) { | |
| 195 // Transmit 1 packet and then wait an rtt plus 1ms. | |
| 196 SendDataPacket(1); | |
| 197 clock_.AdvanceTime( | |
| 198 rtt_stats_.smoothed_rtt().Add(QuicTime::Delta::FromMilliseconds(1))); | |
| 199 | |
| 200 // Transmit 2 packets. | |
| 201 SendDataPacket(2); | |
| 202 SendDataPacket(3); | |
| 203 | |
| 204 // Wait another RTT and ack 2. | |
| 205 clock_.AdvanceTime(rtt_stats_.smoothed_rtt()); | |
| 206 unacked_packets_.IncreaseLargestObserved(2); | |
| 207 unacked_packets_.RemoveFromInFlight(2); | |
| 208 unacked_packets_.NackPacket(1, 1); | |
| 209 QuicPacketSequenceNumber lost[] = {1}; | |
| 210 VerifyLosses(2, lost, arraysize(lost)); | |
| 211 } | |
| 212 | |
| 213 } // namespace | |
| 214 } // namespace test | |
| 215 } // namespace net | |
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