Move network emulation framework under test/network

Bug: webrtc:10138
Change-Id: I654bc124866241ceca65462937e2fad6294cc62b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/144622
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28492}

test/network/cross_traffic.cc

@@ -0,0 +1,183 @@
+/*
+ *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "test/network/cross_traffic.h"
+
+#include <math.h>
+#include <utility>
+
+#include "absl/memory/memory.h"
+#include "absl/types/optional.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/numerics/safe_minmax.h"
+
+namespace webrtc {
+namespace test {
+
+RandomWalkCrossTraffic::RandomWalkCrossTraffic(RandomWalkConfig config,
+                                               TrafficRoute* traffic_route)
+    : config_(config),
+      traffic_route_(traffic_route),
+      random_(config_.random_seed) {
+  sequence_checker_.Detach();
+}
+RandomWalkCrossTraffic::~RandomWalkCrossTraffic() = default;
+
+void RandomWalkCrossTraffic::Process(Timestamp at_time) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  if (last_process_time_.IsMinusInfinity()) {
+    last_process_time_ = at_time;
+  }
+  TimeDelta delta = at_time - last_process_time_;
+  last_process_time_ = at_time;
+
+  if (at_time - last_update_time_ >= config_.update_interval) {
+    intensity_ += random_.Gaussian(config_.bias, config_.variance) *
+                  sqrt((at_time - last_update_time_).seconds<double>());
+    intensity_ = rtc::SafeClamp(intensity_, 0.0, 1.0);
+    last_update_time_ = at_time;
+  }
+  pending_size_ += TrafficRate() * delta;
+
+  if (pending_size_ >= config_.min_packet_size &&
+      at_time >= last_send_time_ + config_.min_packet_interval) {
+    traffic_route_->SendPacket(pending_size_.bytes());
+    pending_size_ = DataSize::Zero();
+    last_send_time_ = at_time;
+  }
+}
+
+DataRate RandomWalkCrossTraffic::TrafficRate() const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  return config_.peak_rate * intensity_;
+}
+
+ColumnPrinter RandomWalkCrossTraffic::StatsPrinter() {
+  return ColumnPrinter::Lambda(
+      "random_walk_cross_traffic_rate",
+      [this](rtc::SimpleStringBuilder& sb) {
+        sb.AppendFormat("%.0lf", TrafficRate().bps() / 8.0);
+      },
+      32);
+}
+
+PulsedPeaksCrossTraffic::PulsedPeaksCrossTraffic(PulsedPeaksConfig config,
+                                                 TrafficRoute* traffic_route)
+    : config_(config), traffic_route_(traffic_route) {
+  sequence_checker_.Detach();
+}
+PulsedPeaksCrossTraffic::~PulsedPeaksCrossTraffic() = default;
+
+void PulsedPeaksCrossTraffic::Process(Timestamp at_time) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  TimeDelta time_since_toggle = at_time - last_update_time_;
+  if (time_since_toggle.IsInfinite() ||
+      (sending_ && time_since_toggle >= config_.send_duration)) {
+    sending_ = false;
+    last_update_time_ = at_time;
+  } else if (!sending_ && time_since_toggle >= config_.hold_duration) {
+    sending_ = true;
+    last_update_time_ = at_time;
+    // Start sending period.
+    last_send_time_ = at_time;
+  }
+
+  if (sending_) {
+    DataSize pending_size = config_.peak_rate * (at_time - last_send_time_);
+
+    if (pending_size >= config_.min_packet_size &&
+        at_time >= last_send_time_ + config_.min_packet_interval) {
+      traffic_route_->SendPacket(pending_size.bytes());
+      last_send_time_ = at_time;
+    }
+  }
+}
+
+DataRate PulsedPeaksCrossTraffic::TrafficRate() const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  return sending_ ? config_.peak_rate : DataRate::Zero();
+}
+
+ColumnPrinter PulsedPeaksCrossTraffic::StatsPrinter() {
+  return ColumnPrinter::Lambda(
+      "pulsed_peaks_cross_traffic_rate",
+      [this](rtc::SimpleStringBuilder& sb) {
+        sb.AppendFormat("%.0lf", TrafficRate().bps() / 8.0);
+      },
+      32);
+}
+
+FakeTcpCrossTraffic::FakeTcpCrossTraffic(FakeTcpConfig config,
+                                         EmulatedRoute* send_route,
+                                         EmulatedRoute* ret_route)
+    : conf_(config), route_(this, send_route, ret_route) {}
+
+void FakeTcpCrossTraffic::Process(Timestamp at_time) {
+  SendPackets(at_time);
+}
+
+void FakeTcpCrossTraffic::OnRequest(int sequence_number, Timestamp at_time) {
+  const size_t kAckPacketSize = 20;
+  route_.SendResponse(kAckPacketSize, sequence_number);
+}
+
+void FakeTcpCrossTraffic::OnResponse(int sequence_number, Timestamp at_time) {
+  ack_received_ = true;
+  auto it = in_flight_.find(sequence_number);
+  if (it != in_flight_.end()) {
+    last_rtt_ = at_time - in_flight_.at(sequence_number);
+    in_flight_.erase(sequence_number);
+  }
+  if (sequence_number - last_acked_seq_num_ > 1) {
+    HandleLoss(at_time);
+  } else if (cwnd_ <= ssthresh_) {
+    cwnd_ += 1;
+  } else {
+    cwnd_ += 1.0f / cwnd_;
+  }
+  last_acked_seq_num_ = std::max(sequence_number, last_acked_seq_num_);
+  SendPackets(at_time);
+}
+
+void FakeTcpCrossTraffic::HandleLoss(Timestamp at_time) {
+  if (at_time - last_reduction_time_ < last_rtt_)
+    return;
+  last_reduction_time_ = at_time;
+  ssthresh_ = std::max(static_cast<int>(in_flight_.size() / 2), 2);
+  cwnd_ = ssthresh_;
+}
+
+void FakeTcpCrossTraffic::SendPackets(Timestamp at_time) {
+  int cwnd = std::ceil(cwnd_);
+  int packets_to_send = std::max(cwnd - static_cast<int>(in_flight_.size()), 0);
+  bool timeouts = false;
+  for (auto it = in_flight_.begin(); it != in_flight_.end();) {
+    if (it->second < at_time - conf_.packet_timeout) {
+      it = in_flight_.erase(it);
+      timeouts = true;
+    } else {
+      ++it;
+    }
+  }
+  if (timeouts)
+    HandleLoss(at_time);
+  for (int i = 0; i < packets_to_send; ++i) {
+    if ((total_sent_ + conf_.packet_size) > conf_.send_limit) {
+      break;
+    }
+    in_flight_.insert({next_sequence_number_, at_time});
+    route_.SendRequest(conf_.packet_size.bytes<size_t>(),
+                       next_sequence_number_++);
+    total_sent_ += conf_.packet_size;
+  }
+}
+
+}  // namespace test
+}  // namespace webrtc