test/network/network_emulation.cc - src - Git at Google

 /*
  *  Copyright (c) 2018 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/network_emulation.h"

 #include <algorithm>
 #include <limits>
 #include <memory>

 #include "api/units/data_size.h"
 #include "rtc_base/bind.h"
 #include "rtc_base/logging.h"

 namespace webrtc {

 EmulatedNetworkIncomingStats EmulatedNetworkStatsImpl::GetOverallIncomingStats()
     const {
   EmulatedNetworkIncomingStats stats;
   for (const auto& entry : incoming_stats_per_source_) {
     const EmulatedNetworkIncomingStats& source = entry.second;
     stats.packets_received += source.packets_received;
     stats.bytes_received += source.bytes_received;
     stats.packets_dropped += source.packets_dropped;
     stats.bytes_dropped += source.bytes_dropped;
     if (stats.first_packet_received_time > source.first_packet_received_time) {
       stats.first_packet_received_time = source.first_packet_received_time;
       stats.first_received_packet_size = source.first_received_packet_size;
     }
     if (stats.last_packet_received_time < source.last_packet_received_time) {
       stats.last_packet_received_time = source.last_packet_received_time;
     }
   }
   return stats;
 }

 EmulatedNetworkStatsBuilder::EmulatedNetworkStatsBuilder() {
   sequence_checker_.Detach();
 }
 EmulatedNetworkStatsBuilder::EmulatedNetworkStatsBuilder(
     rtc::IPAddress local_ip) {
   local_addresses_.push_back(local_ip);
   sequence_checker_.Detach();
 }

 void EmulatedNetworkStatsBuilder::OnPacketSent(Timestamp sent_time,
                                                DataSize packet_size) {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
   RTC_CHECK_GE(packet_size, DataSize::Zero());
   if (first_packet_sent_time_.IsInfinite()) {
     first_packet_sent_time_ = sent_time;
     first_sent_packet_size_ = packet_size;
   }
   last_packet_sent_time_ = sent_time;
   packets_sent_++;
   bytes_sent_ += packet_size;
 }

 void EmulatedNetworkStatsBuilder::OnPacketDropped(rtc::IPAddress source_ip,
                                                   DataSize packet_size) {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
   RTC_CHECK_GE(packet_size, DataSize::Zero());
   EmulatedNetworkIncomingStats& source_stats =
       incoming_stats_per_source_[source_ip];
   source_stats.packets_dropped++;
   source_stats.bytes_dropped += packet_size;
 }

 void EmulatedNetworkStatsBuilder::OnPacketReceived(Timestamp received_time,
                                                    rtc::IPAddress source_ip,
                                                    DataSize packet_size) {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
   RTC_CHECK_GE(packet_size, DataSize::Zero());
   EmulatedNetworkIncomingStats& source_stats =
       incoming_stats_per_source_[source_ip];
   if (source_stats.first_packet_received_time.IsInfinite()) {
     source_stats.first_packet_received_time = received_time;
     source_stats.first_received_packet_size = packet_size;
   }
   source_stats.last_packet_received_time = received_time;
   source_stats.packets_received++;
   source_stats.bytes_received += packet_size;
 }

 void EmulatedNetworkStatsBuilder::AppendEmulatedNetworkStats(
     std::unique_ptr<EmulatedNetworkStats> stats) {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
   RTC_CHECK(stats);
   packets_sent_ += stats->PacketsSent();
   bytes_sent_ += stats->BytesSent();
   if (first_packet_sent_time_ > stats->FirstPacketSentTime()) {
     first_packet_sent_time_ = stats->FirstPacketSentTime();
     first_sent_packet_size_ = stats->FirstSentPacketSize();
   }
   if (last_packet_sent_time_ < stats->LastPacketSentTime()) {
     last_packet_sent_time_ = stats->LastPacketSentTime();
   }
   for (const rtc::IPAddress& addr : stats->LocalAddresses()) {
     local_addresses_.push_back(addr);
   }

   const std::map<rtc::IPAddress, EmulatedNetworkIncomingStats>
       incoming_stats_per_source = stats->IncomingStatsPerSource();
   for (const auto& entry : incoming_stats_per_source) {
     const EmulatedNetworkIncomingStats& source = entry.second;
     EmulatedNetworkIncomingStats& in_stats =
         incoming_stats_per_source_[entry.first];
     in_stats.packets_received += source.packets_received;
     in_stats.bytes_received += source.bytes_received;
     in_stats.packets_dropped += source.packets_dropped;
     in_stats.bytes_dropped += source.bytes_dropped;
     if (in_stats.first_packet_received_time >
         source.first_packet_received_time) {
       in_stats.first_packet_received_time = source.first_packet_received_time;
       in_stats.first_received_packet_size = source.first_received_packet_size;
     }
     if (in_stats.last_packet_received_time < source.last_packet_received_time) {
       in_stats.last_packet_received_time = source.last_packet_received_time;
     }
   }
 }

 std::unique_ptr<EmulatedNetworkStats> EmulatedNetworkStatsBuilder::Build()
     const {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
   return std::make_unique<EmulatedNetworkStatsImpl>(
       packets_sent_, bytes_sent_, local_addresses_, first_sent_packet_size_,
       first_packet_sent_time_, last_packet_sent_time_,
       incoming_stats_per_source_);
 }

 void LinkEmulation::OnPacketReceived(EmulatedIpPacket packet) {
   task_queue_->PostTask([this, packet = std::move(packet)]() mutable {
     RTC_DCHECK_RUN_ON(task_queue_);

     uint64_t packet_id = next_packet_id_++;
     bool sent = network_behavior_->EnqueuePacket(PacketInFlightInfo(
         packet.ip_packet_size(), packet.arrival_time.us(), packet_id));
     if (sent) {
       packets_.emplace_back(StoredPacket{packet_id, std::move(packet), false});
     }
     if (process_task_.Running())
       return;
     absl::optional<int64_t> next_time_us =
         network_behavior_->NextDeliveryTimeUs();
     if (!next_time_us)
       return;
     Timestamp current_time = clock_->CurrentTime();
     process_task_ = RepeatingTaskHandle::DelayedStart(
         task_queue_->Get(),
         std::max(TimeDelta::Zero(),
                  Timestamp::Micros(*next_time_us) - current_time),
         [this]() {
           RTC_DCHECK_RUN_ON(task_queue_);
           Timestamp current_time = clock_->CurrentTime();
           Process(current_time);
           absl::optional<int64_t> next_time_us =
               network_behavior_->NextDeliveryTimeUs();
           if (!next_time_us) {
             process_task_.Stop();
             return TimeDelta::Zero();  // This is ignored.
           }
           RTC_DCHECK_GE(*next_time_us, current_time.us());
           return Timestamp::Micros(*next_time_us) - current_time;
         });
   });
 }

 void LinkEmulation::Process(Timestamp at_time) {
   std::vector<PacketDeliveryInfo> delivery_infos =
       network_behavior_->DequeueDeliverablePackets(at_time.us());
   for (PacketDeliveryInfo& delivery_info : delivery_infos) {
     StoredPacket* packet = nullptr;
     for (auto& stored_packet : packets_) {
       if (stored_packet.id == delivery_info.packet_id) {
         packet = &stored_packet;
         break;
       }
     }
     RTC_CHECK(packet);
     RTC_DCHECK(!packet->removed);
     packet->removed = true;

     if (delivery_info.receive_time_us != PacketDeliveryInfo::kNotReceived) {
       packet->packet.arrival_time =
           Timestamp::Micros(delivery_info.receive_time_us);
       receiver_->OnPacketReceived(std::move(packet->packet));
     }
     while (!packets_.empty() && packets_.front().removed) {
       packets_.pop_front();
     }
   }
 }

 NetworkRouterNode::NetworkRouterNode(rtc::TaskQueue* task_queue)
     : task_queue_(task_queue) {}

 void NetworkRouterNode::OnPacketReceived(EmulatedIpPacket packet) {
   RTC_DCHECK_RUN_ON(task_queue_);
   if (watcher_) {
     watcher_(packet);
   }
   if (filter_) {
     if (!filter_(packet))
       return;
   }
   auto receiver_it = routing_.find(packet.to.ipaddr());
   if (receiver_it == routing_.end()) {
     return;
   }
   RTC_CHECK(receiver_it != routing_.end());

   receiver_it->second->OnPacketReceived(std::move(packet));
 }

 void NetworkRouterNode::SetReceiver(
     const rtc::IPAddress& dest_ip,
     EmulatedNetworkReceiverInterface* receiver) {
   task_queue_->PostTask([=] {
     RTC_DCHECK_RUN_ON(task_queue_);
     EmulatedNetworkReceiverInterface* cur_receiver = routing_[dest_ip];
     RTC_CHECK(cur_receiver == nullptr || cur_receiver == receiver)
         << "Routing for dest_ip=" << dest_ip.ToString() << " already exists";
     routing_[dest_ip] = receiver;
   });
 }

 void NetworkRouterNode::RemoveReceiver(const rtc::IPAddress& dest_ip) {
   RTC_DCHECK_RUN_ON(task_queue_);
   routing_.erase(dest_ip);
 }

 void NetworkRouterNode::SetWatcher(
     std::function<void(const EmulatedIpPacket&)> watcher) {
   task_queue_->PostTask([=] {
     RTC_DCHECK_RUN_ON(task_queue_);
     watcher_ = watcher;
   });
 }

 void NetworkRouterNode::SetFilter(
     std::function<bool(const EmulatedIpPacket&)> filter) {
   task_queue_->PostTask([=] {
     RTC_DCHECK_RUN_ON(task_queue_);
     filter_ = filter;
   });
 }

 EmulatedNetworkNode::EmulatedNetworkNode(
     Clock* clock,
     rtc::TaskQueue* task_queue,
     std::unique_ptr<NetworkBehaviorInterface> network_behavior)
     : router_(task_queue),
       link_(clock, task_queue, std::move(network_behavior), &router_) {}

 void EmulatedNetworkNode::OnPacketReceived(EmulatedIpPacket packet) {
   link_.OnPacketReceived(std::move(packet));
 }

 void EmulatedNetworkNode::CreateRoute(
     const rtc::IPAddress& receiver_ip,
     std::vector<EmulatedNetworkNode*> nodes,
     EmulatedNetworkReceiverInterface* receiver) {
   RTC_CHECK(!nodes.empty());
   for (size_t i = 0; i + 1 < nodes.size(); ++i)
     nodes[i]->router()->SetReceiver(receiver_ip, nodes[i + 1]);
   nodes.back()->router()->SetReceiver(receiver_ip, receiver);
 }

 void EmulatedNetworkNode::ClearRoute(const rtc::IPAddress& receiver_ip,
                                      std::vector<EmulatedNetworkNode*> nodes) {
   for (EmulatedNetworkNode* node : nodes)
     node->router()->RemoveReceiver(receiver_ip);
 }

 EmulatedNetworkNode::~EmulatedNetworkNode() = default;

 EmulatedEndpointImpl::EmulatedEndpointImpl(uint64_t id,
                                            const rtc::IPAddress& ip,
                                            bool is_enabled,
                                            rtc::AdapterType type,
                                            rtc::TaskQueue* task_queue,
                                            Clock* clock)
     : id_(id),
       peer_local_addr_(ip),
       is_enabled_(is_enabled),
       type_(type),
       clock_(clock),
       task_queue_(task_queue),
       router_(task_queue_),
       next_port_(kFirstEphemeralPort),
       stats_builder_(peer_local_addr_) {
   constexpr int kIPv4NetworkPrefixLength = 24;
   constexpr int kIPv6NetworkPrefixLength = 64;

   int prefix_length = 0;
   if (ip.family() == AF_INET) {
     prefix_length = kIPv4NetworkPrefixLength;
   } else if (ip.family() == AF_INET6) {
     prefix_length = kIPv6NetworkPrefixLength;
   }
   rtc::IPAddress prefix = TruncateIP(ip, prefix_length);
   network_ = std::make_unique<rtc::Network>(
       ip.ToString(), "Endpoint id=" + std::to_string(id_), prefix,
       prefix_length, type_);
   network_->AddIP(ip);

   enabled_state_checker_.Detach();
 }
 EmulatedEndpointImpl::~EmulatedEndpointImpl() = default;

 uint64_t EmulatedEndpointImpl::GetId() const {
   return id_;
 }

 void EmulatedEndpointImpl::SendPacket(const rtc::SocketAddress& from,
                                       const rtc::SocketAddress& to,
                                       rtc::CopyOnWriteBuffer packet_data,
                                       uint16_t application_overhead) {
   RTC_CHECK(from.ipaddr() == peer_local_addr_);
   EmulatedIpPacket packet(from, to, std::move(packet_data),
                           clock_->CurrentTime(), application_overhead);
   task_queue_->PostTask([this, packet = std::move(packet)]() mutable {
     RTC_DCHECK_RUN_ON(task_queue_);
     stats_builder_.OnPacketSent(clock_->CurrentTime(),
                                 DataSize::Bytes(packet.ip_packet_size()));

     router_.OnPacketReceived(std::move(packet));
   });
 }

 absl::optional<uint16_t> EmulatedEndpointImpl::BindReceiver(
     uint16_t desired_port,
     EmulatedNetworkReceiverInterface* receiver) {
   rtc::CritScope crit(&receiver_lock_);
   uint16_t port = desired_port;
   if (port == 0) {
     // Because client can specify its own port, next_port_ can be already in
     // use, so we need to find next available port.
     int ports_pool_size =
         std::numeric_limits<uint16_t>::max() - kFirstEphemeralPort + 1;
     for (int i = 0; i < ports_pool_size; ++i) {
       uint16_t next_port = NextPort();
       if (port_to_receiver_.find(next_port) == port_to_receiver_.end()) {
         port = next_port;
         break;
       }
     }
   }
   RTC_CHECK(port != 0) << "Can't find free port for receiver in endpoint "
                        << id_;
   bool result = port_to_receiver_.insert({port, receiver}).second;
   if (!result) {
     RTC_LOG(INFO) << "Can't bind receiver to used port " << desired_port
                   << " in endpoint " << id_;
     return absl::nullopt;
   }
   RTC_LOG(INFO) << "New receiver is binded to endpoint " << id_ << " on port "
                 << port;
   return port;
 }

 uint16_t EmulatedEndpointImpl::NextPort() {
   uint16_t out = next_port_;
   if (next_port_ == std::numeric_limits<uint16_t>::max()) {
     next_port_ = kFirstEphemeralPort;
   } else {
     next_port_++;
   }
   return out;
 }

 void EmulatedEndpointImpl::UnbindReceiver(uint16_t port) {
   rtc::CritScope crit(&receiver_lock_);
   port_to_receiver_.erase(port);
 }

 rtc::IPAddress EmulatedEndpointImpl::GetPeerLocalAddress() const {
   return peer_local_addr_;
 }

 void EmulatedEndpointImpl::OnPacketReceived(EmulatedIpPacket packet) {
   RTC_DCHECK_RUN_ON(task_queue_);
   RTC_CHECK(packet.to.ipaddr() == peer_local_addr_)
       << "Routing error: wrong destination endpoint. Packet.to.ipaddr()=: "
       << packet.to.ipaddr().ToString()
       << "; Receiver peer_local_addr_=" << peer_local_addr_.ToString();
   rtc::CritScope crit(&receiver_lock_);
   stats_builder_.OnPacketReceived(clock_->CurrentTime(), packet.from.ipaddr(),
                                   DataSize::Bytes(packet.ip_packet_size()));
   auto it = port_to_receiver_.find(packet.to.port());
   if (it == port_to_receiver_.end()) {
     // It can happen, that remote peer closed connection, but there still some
     // packets, that are going to it. It can happen during peer connection close
     // process: one peer closed connection, second still sending data.
     RTC_LOG(INFO) << "Drop packet: no receiver registered in " << id_
                   << " on port " << packet.to.port();
     stats_builder_.OnPacketDropped(packet.from.ipaddr(),
                                    DataSize::Bytes(packet.ip_packet_size()));
     return;
   }
   // Endpoint assumes frequent calls to bind and unbind methods, so it holds
   // lock during packet processing to ensure that receiver won't be deleted
   // before call to OnPacketReceived.
   it->second->OnPacketReceived(std::move(packet));
 }

 void EmulatedEndpointImpl::Enable() {
   RTC_DCHECK_RUN_ON(&enabled_state_checker_);
   RTC_CHECK(!is_enabled_);
   is_enabled_ = true;
 }

 void EmulatedEndpointImpl::Disable() {
   RTC_DCHECK_RUN_ON(&enabled_state_checker_);
   RTC_CHECK(is_enabled_);
   is_enabled_ = false;
 }

 bool EmulatedEndpointImpl::Enabled() const {
   RTC_DCHECK_RUN_ON(&enabled_state_checker_);
   return is_enabled_;
 }

 std::unique_ptr<EmulatedNetworkStats> EmulatedEndpointImpl::stats() const {
   RTC_DCHECK_RUN_ON(task_queue_);
   return stats_builder_.Build();
 }

 EndpointsContainer::EndpointsContainer(
     const std::vector<EmulatedEndpointImpl*>& endpoints)
     : endpoints_(endpoints) {}

 EmulatedEndpointImpl* EndpointsContainer::LookupByLocalAddress(
     const rtc::IPAddress& local_ip) const {
   for (auto* endpoint : endpoints_) {
     rtc::IPAddress peer_local_address = endpoint->GetPeerLocalAddress();
     if (peer_local_address == local_ip) {
       return endpoint;
     }
   }
   RTC_CHECK(false) << "No network found for address" << local_ip.ToString();
 }

 bool EndpointsContainer::HasEndpoint(EmulatedEndpointImpl* endpoint) const {
   for (auto* e : endpoints_) {
     if (e->GetId() == endpoint->GetId()) {
       return true;
     }
   }
   return false;
 }

 std::vector<std::unique_ptr<rtc::Network>>
 EndpointsContainer::GetEnabledNetworks() const {
   std::vector<std::unique_ptr<rtc::Network>> networks;
   for (auto* endpoint : endpoints_) {
     if (endpoint->Enabled()) {
       networks.emplace_back(
           std::make_unique<rtc::Network>(endpoint->network()));
     }
   }
   return networks;
 }

 std::unique_ptr<EmulatedNetworkStats> EndpointsContainer::GetStats() const {
   EmulatedNetworkStatsBuilder stats_builder;
   for (auto* endpoint : endpoints_) {
     stats_builder.AppendEmulatedNetworkStats(endpoint->stats());
   }
   return stats_builder.Build();
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2018 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/network_emulation.h"

	#include <algorithm>
	#include <limits>
	#include <memory>

	#include "api/units/data_size.h"
	#include "rtc_base/bind.h"
	#include "rtc_base/logging.h"

	namespace webrtc {

	EmulatedNetworkIncomingStats EmulatedNetworkStatsImpl::GetOverallIncomingStats()
	const {
	EmulatedNetworkIncomingStats stats;
	for (const auto& entry : incoming_stats_per_source_) {
	const EmulatedNetworkIncomingStats& source = entry.second;
	stats.packets_received += source.packets_received;
	stats.bytes_received += source.bytes_received;
	stats.packets_dropped += source.packets_dropped;
	stats.bytes_dropped += source.bytes_dropped;
	if (stats.first_packet_received_time > source.first_packet_received_time) {
	stats.first_packet_received_time = source.first_packet_received_time;
	stats.first_received_packet_size = source.first_received_packet_size;
	}
	if (stats.last_packet_received_time < source.last_packet_received_time) {
	stats.last_packet_received_time = source.last_packet_received_time;
	}
	}
	return stats;
	}

	EmulatedNetworkStatsBuilder::EmulatedNetworkStatsBuilder() {
	sequence_checker_.Detach();
	}
	EmulatedNetworkStatsBuilder::EmulatedNetworkStatsBuilder(
	rtc::IPAddress local_ip) {
	local_addresses_.push_back(local_ip);
	sequence_checker_.Detach();
	}

	void EmulatedNetworkStatsBuilder::OnPacketSent(Timestamp sent_time,
	DataSize packet_size) {
	RTC_DCHECK_RUN_ON(&sequence_checker_);
	RTC_CHECK_GE(packet_size, DataSize::Zero());
	if (first_packet_sent_time_.IsInfinite()) {
	first_packet_sent_time_ = sent_time;
	first_sent_packet_size_ = packet_size;
	}
	last_packet_sent_time_ = sent_time;
	packets_sent_++;
	bytes_sent_ += packet_size;
	}

	void EmulatedNetworkStatsBuilder::OnPacketDropped(rtc::IPAddress source_ip,
	DataSize packet_size) {
	RTC_DCHECK_RUN_ON(&sequence_checker_);
	RTC_CHECK_GE(packet_size, DataSize::Zero());
	EmulatedNetworkIncomingStats& source_stats =
	incoming_stats_per_source_[source_ip];
	source_stats.packets_dropped++;
	source_stats.bytes_dropped += packet_size;
	}

	void EmulatedNetworkStatsBuilder::OnPacketReceived(Timestamp received_time,
	rtc::IPAddress source_ip,
	DataSize packet_size) {
	RTC_DCHECK_RUN_ON(&sequence_checker_);
	RTC_CHECK_GE(packet_size, DataSize::Zero());
	EmulatedNetworkIncomingStats& source_stats =
	incoming_stats_per_source_[source_ip];
	if (source_stats.first_packet_received_time.IsInfinite()) {
	source_stats.first_packet_received_time = received_time;
	source_stats.first_received_packet_size = packet_size;
	}
	source_stats.last_packet_received_time = received_time;
	source_stats.packets_received++;
	source_stats.bytes_received += packet_size;
	}

	void EmulatedNetworkStatsBuilder::AppendEmulatedNetworkStats(
	std::unique_ptr<EmulatedNetworkStats> stats) {
	RTC_DCHECK_RUN_ON(&sequence_checker_);
	RTC_CHECK(stats);
	packets_sent_ += stats->PacketsSent();
	bytes_sent_ += stats->BytesSent();
	if (first_packet_sent_time_ > stats->FirstPacketSentTime()) {
	first_packet_sent_time_ = stats->FirstPacketSentTime();
	first_sent_packet_size_ = stats->FirstSentPacketSize();
	}
	if (last_packet_sent_time_ < stats->LastPacketSentTime()) {
	last_packet_sent_time_ = stats->LastPacketSentTime();
	}
	for (const rtc::IPAddress& addr : stats->LocalAddresses()) {
	local_addresses_.push_back(addr);
	}

	const std::map<rtc::IPAddress, EmulatedNetworkIncomingStats>
	incoming_stats_per_source = stats->IncomingStatsPerSource();
	for (const auto& entry : incoming_stats_per_source) {
	const EmulatedNetworkIncomingStats& source = entry.second;
	EmulatedNetworkIncomingStats& in_stats =
	incoming_stats_per_source_[entry.first];
	in_stats.packets_received += source.packets_received;
	in_stats.bytes_received += source.bytes_received;
	in_stats.packets_dropped += source.packets_dropped;
	in_stats.bytes_dropped += source.bytes_dropped;
	if (in_stats.first_packet_received_time >
	source.first_packet_received_time) {
	in_stats.first_packet_received_time = source.first_packet_received_time;
	in_stats.first_received_packet_size = source.first_received_packet_size;
	}
	if (in_stats.last_packet_received_time < source.last_packet_received_time) {
	in_stats.last_packet_received_time = source.last_packet_received_time;
	}
	}
	}

	std::unique_ptr<EmulatedNetworkStats> EmulatedNetworkStatsBuilder::Build()
	const {
	RTC_DCHECK_RUN_ON(&sequence_checker_);
	return std::make_unique<EmulatedNetworkStatsImpl>(
	packets_sent_, bytes_sent_, local_addresses_, first_sent_packet_size_,
	first_packet_sent_time_, last_packet_sent_time_,
	incoming_stats_per_source_);
	}

	void LinkEmulation::OnPacketReceived(EmulatedIpPacket packet) {
	task_queue_->PostTask([this, packet = std::move(packet)]() mutable {
	RTC_DCHECK_RUN_ON(task_queue_);

	uint64_t packet_id = next_packet_id_++;
	bool sent = network_behavior_->EnqueuePacket(PacketInFlightInfo(
	packet.ip_packet_size(), packet.arrival_time.us(), packet_id));
	if (sent) {
	packets_.emplace_back(StoredPacket{packet_id, std::move(packet), false});
	}
	if (process_task_.Running())
	return;
	absl::optional<int64_t> next_time_us =
	network_behavior_->NextDeliveryTimeUs();
	if (!next_time_us)
	return;
	Timestamp current_time = clock_->CurrentTime();
	process_task_ = RepeatingTaskHandle::DelayedStart(
	task_queue_->Get(),
	std::max(TimeDelta::Zero(),
	Timestamp::Micros(*next_time_us) - current_time),
	[this]() {
	RTC_DCHECK_RUN_ON(task_queue_);
	Timestamp current_time = clock_->CurrentTime();
	Process(current_time);
	absl::optional<int64_t> next_time_us =
	network_behavior_->NextDeliveryTimeUs();
	if (!next_time_us) {
	process_task_.Stop();
	return TimeDelta::Zero(); // This is ignored.
	}
	RTC_DCHECK_GE(*next_time_us, current_time.us());
	return Timestamp::Micros(*next_time_us) - current_time;
	});
	});
	}

	void LinkEmulation::Process(Timestamp at_time) {
	std::vector<PacketDeliveryInfo> delivery_infos =
	network_behavior_->DequeueDeliverablePackets(at_time.us());
	for (PacketDeliveryInfo& delivery_info : delivery_infos) {
	StoredPacket* packet = nullptr;
	for (auto& stored_packet : packets_) {
	if (stored_packet.id == delivery_info.packet_id) {
	packet = &stored_packet;
	break;
	}
	}
	RTC_CHECK(packet);
	RTC_DCHECK(!packet->removed);
	packet->removed = true;

	if (delivery_info.receive_time_us != PacketDeliveryInfo::kNotReceived) {
	packet->packet.arrival_time =
	Timestamp::Micros(delivery_info.receive_time_us);
	receiver_->OnPacketReceived(std::move(packet->packet));
	}
	while (!packets_.empty() && packets_.front().removed) {
	packets_.pop_front();
	}
	}
	}

	NetworkRouterNode::NetworkRouterNode(rtc::TaskQueue* task_queue)
	: task_queue_(task_queue) {}

	void NetworkRouterNode::OnPacketReceived(EmulatedIpPacket packet) {
	RTC_DCHECK_RUN_ON(task_queue_);
	if (watcher_) {
	watcher_(packet);
	}
	if (filter_) {
	if (!filter_(packet))
	return;
	}
	auto receiver_it = routing_.find(packet.to.ipaddr());
	if (receiver_it == routing_.end()) {
	return;
	}
	RTC_CHECK(receiver_it != routing_.end());

	receiver_it->second->OnPacketReceived(std::move(packet));
	}

	void NetworkRouterNode::SetReceiver(
	const rtc::IPAddress& dest_ip,
	EmulatedNetworkReceiverInterface* receiver) {
	task_queue_->PostTask([=] {
	RTC_DCHECK_RUN_ON(task_queue_);
	EmulatedNetworkReceiverInterface* cur_receiver = routing_[dest_ip];
	RTC_CHECK(cur_receiver == nullptr \|\| cur_receiver == receiver)
	<< "Routing for dest_ip=" << dest_ip.ToString() << " already exists";
	routing_[dest_ip] = receiver;
	});
	}

	void NetworkRouterNode::RemoveReceiver(const rtc::IPAddress& dest_ip) {
	RTC_DCHECK_RUN_ON(task_queue_);
	routing_.erase(dest_ip);
	}

	void NetworkRouterNode::SetWatcher(
	std::function<void(const EmulatedIpPacket&)> watcher) {
	task_queue_->PostTask([=] {
	RTC_DCHECK_RUN_ON(task_queue_);
	watcher_ = watcher;
	});
	}

	void NetworkRouterNode::SetFilter(
	std::function<bool(const EmulatedIpPacket&)> filter) {
	task_queue_->PostTask([=] {
	RTC_DCHECK_RUN_ON(task_queue_);
	filter_ = filter;
	});
	}

	EmulatedNetworkNode::EmulatedNetworkNode(
	Clock* clock,
	rtc::TaskQueue* task_queue,
	std::unique_ptr<NetworkBehaviorInterface> network_behavior)
	: router_(task_queue),
	link_(clock, task_queue, std::move(network_behavior), &router_) {}

	void EmulatedNetworkNode::OnPacketReceived(EmulatedIpPacket packet) {
	link_.OnPacketReceived(std::move(packet));
	}

	void EmulatedNetworkNode::CreateRoute(
	const rtc::IPAddress& receiver_ip,
	std::vector<EmulatedNetworkNode*> nodes,
	EmulatedNetworkReceiverInterface* receiver) {
	RTC_CHECK(!nodes.empty());
	for (size_t i = 0; i + 1 < nodes.size(); ++i)
	nodes[i]->router()->SetReceiver(receiver_ip, nodes[i + 1]);
	nodes.back()->router()->SetReceiver(receiver_ip, receiver);
	}

	void EmulatedNetworkNode::ClearRoute(const rtc::IPAddress& receiver_ip,
	std::vector<EmulatedNetworkNode*> nodes) {
	for (EmulatedNetworkNode* node : nodes)
	node->router()->RemoveReceiver(receiver_ip);
	}

	EmulatedNetworkNode::~EmulatedNetworkNode() = default;

	EmulatedEndpointImpl::EmulatedEndpointImpl(uint64_t id,
	const rtc::IPAddress& ip,
	bool is_enabled,
	rtc::AdapterType type,
	rtc::TaskQueue* task_queue,
	Clock* clock)
	: id_(id),
	peer_local_addr_(ip),
	is_enabled_(is_enabled),
	type_(type),
	clock_(clock),
	task_queue_(task_queue),
	router_(task_queue_),
	next_port_(kFirstEphemeralPort),
	stats_builder_(peer_local_addr_) {
	constexpr int kIPv4NetworkPrefixLength = 24;
	constexpr int kIPv6NetworkPrefixLength = 64;

	int prefix_length = 0;
	if (ip.family() == AF_INET) {
	prefix_length = kIPv4NetworkPrefixLength;
	} else if (ip.family() == AF_INET6) {
	prefix_length = kIPv6NetworkPrefixLength;
	}
	rtc::IPAddress prefix = TruncateIP(ip, prefix_length);
	network_ = std::make_unique<rtc::Network>(
	ip.ToString(), "Endpoint id=" + std::to_string(id_), prefix,
	prefix_length, type_);
	network_->AddIP(ip);

	enabled_state_checker_.Detach();
	}
	EmulatedEndpointImpl::~EmulatedEndpointImpl() = default;

	uint64_t EmulatedEndpointImpl::GetId() const {
	return id_;
	}

	void EmulatedEndpointImpl::SendPacket(const rtc::SocketAddress& from,
	const rtc::SocketAddress& to,
	rtc::CopyOnWriteBuffer packet_data,
	uint16_t application_overhead) {
	RTC_CHECK(from.ipaddr() == peer_local_addr_);
	EmulatedIpPacket packet(from, to, std::move(packet_data),
	clock_->CurrentTime(), application_overhead);
	task_queue_->PostTask([this, packet = std::move(packet)]() mutable {
	RTC_DCHECK_RUN_ON(task_queue_);
	stats_builder_.OnPacketSent(clock_->CurrentTime(),
	DataSize::Bytes(packet.ip_packet_size()));

	router_.OnPacketReceived(std::move(packet));
	});
	}

	absl::optional<uint16_t> EmulatedEndpointImpl::BindReceiver(
	uint16_t desired_port,
	EmulatedNetworkReceiverInterface* receiver) {
	rtc::CritScope crit(&receiver_lock_);
	uint16_t port = desired_port;
	if (port == 0) {
	// Because client can specify its own port, next_port_ can be already in
	// use, so we need to find next available port.
	int ports_pool_size =
	std::numeric_limits<uint16_t>::max() - kFirstEphemeralPort + 1;
	for (int i = 0; i < ports_pool_size; ++i) {
	uint16_t next_port = NextPort();
	if (port_to_receiver_.find(next_port) == port_to_receiver_.end()) {
	port = next_port;
	break;
	}
	}
	}
	RTC_CHECK(port != 0) << "Can't find free port for receiver in endpoint "
	<< id_;
	bool result = port_to_receiver_.insert({port, receiver}).second;
	if (!result) {
	RTC_LOG(INFO) << "Can't bind receiver to used port " << desired_port
	<< " in endpoint " << id_;
	return absl::nullopt;
	}
	RTC_LOG(INFO) << "New receiver is binded to endpoint " << id_ << " on port "
	<< port;
	return port;
	}

	uint16_t EmulatedEndpointImpl::NextPort() {
	uint16_t out = next_port_;
	if (next_port_ == std::numeric_limits<uint16_t>::max()) {
	next_port_ = kFirstEphemeralPort;
	} else {
	next_port_++;
	}
	return out;
	}

	void EmulatedEndpointImpl::UnbindReceiver(uint16_t port) {
	rtc::CritScope crit(&receiver_lock_);
	port_to_receiver_.erase(port);
	}

	rtc::IPAddress EmulatedEndpointImpl::GetPeerLocalAddress() const {
	return peer_local_addr_;
	}

	void EmulatedEndpointImpl::OnPacketReceived(EmulatedIpPacket packet) {
	RTC_DCHECK_RUN_ON(task_queue_);
	RTC_CHECK(packet.to.ipaddr() == peer_local_addr_)
	<< "Routing error: wrong destination endpoint. Packet.to.ipaddr()=: "
	<< packet.to.ipaddr().ToString()
	<< "; Receiver peer_local_addr_=" << peer_local_addr_.ToString();
	rtc::CritScope crit(&receiver_lock_);
	stats_builder_.OnPacketReceived(clock_->CurrentTime(), packet.from.ipaddr(),
	DataSize::Bytes(packet.ip_packet_size()));
	auto it = port_to_receiver_.find(packet.to.port());
	if (it == port_to_receiver_.end()) {
	// It can happen, that remote peer closed connection, but there still some
	// packets, that are going to it. It can happen during peer connection close
	// process: one peer closed connection, second still sending data.
	RTC_LOG(INFO) << "Drop packet: no receiver registered in " << id_
	<< " on port " << packet.to.port();
	stats_builder_.OnPacketDropped(packet.from.ipaddr(),
	DataSize::Bytes(packet.ip_packet_size()));
	return;
	}
	// Endpoint assumes frequent calls to bind and unbind methods, so it holds
	// lock during packet processing to ensure that receiver won't be deleted
	// before call to OnPacketReceived.
	it->second->OnPacketReceived(std::move(packet));
	}

	void EmulatedEndpointImpl::Enable() {
	RTC_DCHECK_RUN_ON(&enabled_state_checker_);
	RTC_CHECK(!is_enabled_);
	is_enabled_ = true;
	}

	void EmulatedEndpointImpl::Disable() {
	RTC_DCHECK_RUN_ON(&enabled_state_checker_);
	RTC_CHECK(is_enabled_);
	is_enabled_ = false;
	}

	bool EmulatedEndpointImpl::Enabled() const {
	RTC_DCHECK_RUN_ON(&enabled_state_checker_);
	return is_enabled_;
	}

	std::unique_ptr<EmulatedNetworkStats> EmulatedEndpointImpl::stats() const {
	RTC_DCHECK_RUN_ON(task_queue_);
	return stats_builder_.Build();
	}

	EndpointsContainer::EndpointsContainer(
	const std::vector<EmulatedEndpointImpl*>& endpoints)
	: endpoints_(endpoints) {}

	EmulatedEndpointImpl* EndpointsContainer::LookupByLocalAddress(
	const rtc::IPAddress& local_ip) const {
	for (auto* endpoint : endpoints_) {
	rtc::IPAddress peer_local_address = endpoint->GetPeerLocalAddress();
	if (peer_local_address == local_ip) {
	return endpoint;
	}
	}
	RTC_CHECK(false) << "No network found for address" << local_ip.ToString();
	}

	bool EndpointsContainer::HasEndpoint(EmulatedEndpointImpl* endpoint) const {
	for (auto* e : endpoints_) {
	if (e->GetId() == endpoint->GetId()) {
	return true;
	}
	}
	return false;
	}

	std::vector<std::unique_ptr<rtc::Network>>
	EndpointsContainer::GetEnabledNetworks() const {
	std::vector<std::unique_ptr<rtc::Network>> networks;
	for (auto* endpoint : endpoints_) {
	if (endpoint->Enabled()) {
	networks.emplace_back(
	std::make_unique<rtc::Network>(endpoint->network()));
	}
	}
	return networks;
	}

	std::unique_ptr<EmulatedNetworkStats> EndpointsContainer::GetStats() const {
	EmulatedNetworkStatsBuilder stats_builder;
	for (auto* endpoint : endpoints_) {
	stats_builder.AppendEmulatedNetworkStats(endpoint->stats());
	}
	return stats_builder.Build();
	}

	} // namespace webrtc