stefan@webrtc.org | cd117d2 | 2013-12-18 20:28:25 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | #include "webrtc/test/fake_network_pipe.h" |
| 12 | |
| 13 | #include <assert.h> |
| 14 | #include <math.h> |
| 15 | #include <string.h> |
| 16 | #include <algorithm> |
| 17 | |
| 18 | #include "webrtc/call.h" |
| 19 | #include "webrtc/system_wrappers/interface/critical_section_wrapper.h" |
| 20 | #include "webrtc/system_wrappers/interface/tick_util.h" |
| 21 | |
| 22 | namespace webrtc { |
| 23 | |
| 24 | const double kPi = 3.14159265; |
| 25 | const int kDefaultProcessIntervalMs = 30; |
| 26 | |
| 27 | static int GaussianRandom(int mean_delay_ms, int standard_deviation_ms) { |
| 28 | // Creating a Normal distribution variable from two independent uniform |
| 29 | // variables based on the Box-Muller transform. |
| 30 | double uniform1 = (rand() + 1.0) / (RAND_MAX + 1.0); // NOLINT |
| 31 | double uniform2 = (rand() + 1.0) / (RAND_MAX + 1.0); // NOLINT |
| 32 | return static_cast<int>(mean_delay_ms + standard_deviation_ms * |
| 33 | sqrt(-2 * log(uniform1)) * cos(2 * kPi * uniform2)); |
| 34 | } |
| 35 | |
| 36 | class NetworkPacket { |
| 37 | public: |
| 38 | NetworkPacket(const uint8_t* data, size_t length, int64_t send_time, |
| 39 | int64_t arrival_time) |
| 40 | : data_(NULL), |
| 41 | data_length_(length), |
| 42 | send_time_(send_time), |
| 43 | arrival_time_(arrival_time) { |
| 44 | data_ = new uint8_t[length]; |
| 45 | memcpy(data_, data, length); |
| 46 | } |
| 47 | ~NetworkPacket() { |
| 48 | delete [] data_; |
| 49 | } |
| 50 | |
| 51 | uint8_t* data() const { return data_; } |
| 52 | size_t data_length() const { return data_length_; } |
| 53 | int64_t send_time() const { return send_time_; } |
| 54 | int64_t arrival_time() const { return arrival_time_; } |
| 55 | void IncrementArrivalTime(int64_t extra_delay) { |
| 56 | arrival_time_+= extra_delay; |
| 57 | } |
| 58 | |
| 59 | private: |
| 60 | // The packet data. |
| 61 | uint8_t* data_; |
| 62 | // Length of data_. |
| 63 | size_t data_length_; |
| 64 | // The time the packet was sent out on the network. |
| 65 | const int64_t send_time_; |
| 66 | // The time the packet should arrive at the reciver. |
| 67 | int64_t arrival_time_; |
| 68 | }; |
| 69 | |
| 70 | FakeNetworkPipe::FakeNetworkPipe( |
| 71 | const FakeNetworkPipe::Config& config) |
| 72 | : lock_(CriticalSectionWrapper::CreateCriticalSection()), |
| 73 | packet_receiver_(NULL), |
| 74 | config_(config), |
| 75 | dropped_packets_(0), |
| 76 | sent_packets_(0), |
| 77 | total_packet_delay_(0), |
| 78 | next_process_time_(TickTime::MillisecondTimestamp()) { |
| 79 | } |
| 80 | |
| 81 | FakeNetworkPipe::~FakeNetworkPipe() { |
| 82 | while (!capacity_link_.empty()) { |
| 83 | delete capacity_link_.front(); |
| 84 | capacity_link_.pop(); |
| 85 | } |
| 86 | while (!delay_link_.empty()) { |
| 87 | delete delay_link_.front(); |
| 88 | delay_link_.pop(); |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | void FakeNetworkPipe::SetReceiver(PacketReceiver* receiver) { |
| 93 | packet_receiver_ = receiver; |
| 94 | } |
| 95 | |
| 96 | void FakeNetworkPipe::SendPacket(const uint8_t* data, size_t data_length) { |
| 97 | // A NULL packet_receiver_ means that this pipe will terminate the flow of |
| 98 | // packets. |
| 99 | if (packet_receiver_ == NULL) |
| 100 | return; |
| 101 | CriticalSectionScoped crit(lock_.get()); |
| 102 | if (config_.queue_length > 0 && |
| 103 | capacity_link_.size() >= config_.queue_length) { |
| 104 | // Too many packet on the link, drop this one. |
| 105 | ++dropped_packets_; |
| 106 | return; |
| 107 | } |
| 108 | |
| 109 | int64_t time_now = TickTime::MillisecondTimestamp(); |
| 110 | |
| 111 | // Delay introduced by the link capacity. |
| 112 | int64_t capacity_delay_ms = 0; |
| 113 | if (config_.link_capacity_kbps > 0) |
| 114 | capacity_delay_ms = data_length / (config_.link_capacity_kbps / 8); |
| 115 | int64_t network_start_time = time_now; |
| 116 | |
| 117 | // Check if there already are packets on the link and change network start |
| 118 | // time if there is. |
| 119 | if (capacity_link_.size() > 0) |
| 120 | network_start_time = capacity_link_.back()->arrival_time(); |
| 121 | |
| 122 | int64_t arrival_time = network_start_time + capacity_delay_ms; |
| 123 | NetworkPacket* packet = new NetworkPacket(data, data_length, time_now, |
| 124 | arrival_time); |
| 125 | capacity_link_.push(packet); |
| 126 | } |
| 127 | |
| 128 | float FakeNetworkPipe::PercentageLoss() { |
| 129 | CriticalSectionScoped crit(lock_.get()); |
| 130 | if (sent_packets_ == 0) |
| 131 | return 0; |
| 132 | |
| 133 | return static_cast<float>(dropped_packets_) / |
| 134 | (sent_packets_ + dropped_packets_); |
| 135 | } |
| 136 | |
| 137 | int FakeNetworkPipe::AverageDelay() { |
| 138 | CriticalSectionScoped crit(lock_.get()); |
| 139 | if (sent_packets_ == 0) |
| 140 | return 0; |
| 141 | |
| 142 | return total_packet_delay_ / static_cast<int>(sent_packets_); |
| 143 | } |
| 144 | |
| 145 | void FakeNetworkPipe::Process() { |
| 146 | int64_t time_now = TickTime::MillisecondTimestamp(); |
| 147 | std::queue<NetworkPacket*> packets_to_deliver; |
| 148 | { |
| 149 | CriticalSectionScoped crit(lock_.get()); |
| 150 | // Check the capacity link first. |
| 151 | while (capacity_link_.size() > 0 && |
| 152 | time_now >= capacity_link_.front()->arrival_time()) { |
| 153 | // Time to get this packet. |
| 154 | NetworkPacket* packet = capacity_link_.front(); |
| 155 | capacity_link_.pop(); |
| 156 | |
| 157 | // Add extra delay and jitter, but make sure the arrival time is not |
| 158 | // earlier than the last packet in the queue. |
| 159 | int extra_delay = GaussianRandom(config_.queue_delay_ms, |
| 160 | config_.delay_standard_deviation_ms); |
| 161 | if (delay_link_.size() > 0 && |
| 162 | packet->arrival_time() + extra_delay < |
| 163 | delay_link_.back()->arrival_time()) { |
| 164 | extra_delay = delay_link_.back()->arrival_time() - |
| 165 | packet->arrival_time(); |
| 166 | } |
| 167 | packet->IncrementArrivalTime(extra_delay); |
| 168 | if (packet->arrival_time() < next_process_time_) |
| 169 | next_process_time_ = packet->arrival_time(); |
| 170 | delay_link_.push(packet); |
| 171 | } |
| 172 | |
| 173 | // Check the extra delay queue. |
| 174 | while (delay_link_.size() > 0 && |
| 175 | time_now >= delay_link_.front()->arrival_time()) { |
| 176 | // Deliver this packet. |
| 177 | NetworkPacket* packet = delay_link_.front(); |
| 178 | packets_to_deliver.push(packet); |
| 179 | delay_link_.pop(); |
| 180 | // |time_now| might be later than when the packet should have arrived, due |
| 181 | // to NetworkProcess being called too late. For stats, use the time it |
| 182 | // should have been on the link. |
| 183 | total_packet_delay_ += packet->arrival_time() - packet->send_time(); |
| 184 | } |
| 185 | sent_packets_ += packets_to_deliver.size(); |
| 186 | } |
| 187 | while (!packets_to_deliver.empty()) { |
| 188 | NetworkPacket* packet = packets_to_deliver.front(); |
| 189 | packets_to_deliver.pop(); |
| 190 | packet_receiver_->DeliverPacket(packet->data(), packet->data_length()); |
| 191 | delete packet; |
| 192 | } |
| 193 | } |
| 194 | |
| 195 | int FakeNetworkPipe::TimeUntilNextProcess() const { |
| 196 | CriticalSectionScoped crit(lock_.get()); |
| 197 | if (capacity_link_.size() == 0 || delay_link_.size() == 0) |
| 198 | return kDefaultProcessIntervalMs; |
| 199 | return std::max(static_cast<int>(next_process_time_ - |
| 200 | TickTime::MillisecondTimestamp()), 0); |
| 201 | } |
| 202 | |
| 203 | } // namespace webrtc |