test/scenario/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/scenario/network/network_emulation.h"

 #include <limits>
 #include <memory>

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

 namespace webrtc {

 EmulatedIpPacket::EmulatedIpPacket(const rtc::SocketAddress& from,
                                    const rtc::SocketAddress& to,
                                    rtc::CopyOnWriteBuffer data,
                                    Timestamp arrival_time)
     : from(from),
       to(to),
       data(data),
       arrival_time(arrival_time) {}

 void LinkEmulation::OnPacketReceived(EmulatedIpPacket packet) {
   struct Closure {
     void operator()() {
       RTC_DCHECK_RUN_ON(link->task_queue_);
       link->HandlePacketReceived(std::move(packet));
     }
     LinkEmulation* link;
     EmulatedIpPacket packet;
   };
   task_queue_->PostTask(Closure{this, std::move(packet)});
 }

 void LinkEmulation::HandlePacketReceived(EmulatedIpPacket packet) {
   uint64_t packet_id = next_packet_id_++;
   bool sent = network_behavior_->EnqueuePacket(
       PacketInFlightInfo(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 = Timestamp::us(clock_->TimeInMicroseconds());
   process_task_ = RepeatingTaskHandle::DelayedStart(
       task_queue_->Get(),
       std::max(TimeDelta::Zero(), Timestamp::us(*next_time_us) - current_time),
       [this]() {
         RTC_DCHECK_RUN_ON(task_queue_);
         Timestamp current_time = Timestamp::us(clock_->TimeInMicroseconds());
         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::us(*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::us(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_);
   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(
     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(rtc::IPAddress dest_ip) {
   RTC_DCHECK_RUN_ON(task_queue_);
   routing_.erase(dest_ip);
 }

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

 EmulatedNetworkNode::~EmulatedNetworkNode() = default;

 EmulatedEndpoint::EmulatedEndpoint(uint64_t id,
                                    const rtc::IPAddress& ip,
                                    bool is_enabled,
                                    rtc::TaskQueue* task_queue,
                                    Clock* clock)
     : id_(id),
       peer_local_addr_(ip),
       is_enabled_(is_enabled),
       clock_(clock),
       task_queue_(task_queue),
       router_(task_queue_),
       next_port_(kFirstEphemeralPort) {
   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_ = absl::make_unique<rtc::Network>(
       ip.ToString(), "Endpoint id=" + std::to_string(id_), prefix,
       prefix_length, rtc::AdapterType::ADAPTER_TYPE_UNKNOWN);
   network_->AddIP(ip);

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

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

 void EmulatedEndpoint::SendPacket(const rtc::SocketAddress& from,
                                   const rtc::SocketAddress& to,
                                   rtc::CopyOnWriteBuffer packet) {
   RTC_CHECK(from.ipaddr() == peer_local_addr_);
   struct Closure {
     void operator()() {
       endpoint->UpdateSendStats(packet);
       endpoint->router_.OnPacketReceived(std::move(packet));
     }
     EmulatedEndpoint* endpoint;
     EmulatedIpPacket packet;
   };
   task_queue_->PostTask(Closure{
       this, EmulatedIpPacket(from, to, std::move(packet),
                              Timestamp::us(clock_->TimeInMicroseconds()))});
 }

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

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

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

 void EmulatedEndpoint::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_);
   UpdateReceiveStats(packet);
   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_.packets_dropped++;
     stats_.bytes_dropped += DataSize::bytes(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 EmulatedEndpoint::Enable() {
   RTC_DCHECK_RUN_ON(&enabled_state_checker_);
   RTC_CHECK(!is_enabled_);
   is_enabled_ = true;
 }

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

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

 EmulatedNetworkStats EmulatedEndpoint::stats() {
   RTC_DCHECK_RUN_ON(task_queue_);
   return stats_;
 }

 void EmulatedEndpoint::UpdateSendStats(const EmulatedIpPacket& packet) {
   RTC_DCHECK_RUN_ON(task_queue_);
   Timestamp current_time = Timestamp::us(clock_->TimeInMicroseconds());
   if (stats_.first_packet_sent_time.IsInfinite()) {
     stats_.first_packet_sent_time = current_time;
     stats_.first_sent_packet_size = DataSize::bytes(packet.size());
   }
   stats_.last_packet_sent_time = current_time;
   stats_.packets_sent++;
   stats_.bytes_sent += DataSize::bytes(packet.size());
 }

 void EmulatedEndpoint::UpdateReceiveStats(const EmulatedIpPacket& packet) {
   RTC_DCHECK_RUN_ON(task_queue_);
   Timestamp current_time = Timestamp::us(clock_->TimeInMicroseconds());
   if (stats_.first_packet_received_time.IsInfinite()) {
     stats_.first_packet_received_time = current_time;
     stats_.first_received_packet_size = DataSize::bytes(packet.size());
   }
   stats_.last_packet_received_time = current_time;
   stats_.packets_received++;
   stats_.bytes_received += DataSize::bytes(packet.size());
 }

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

 EmulatedEndpoint* 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(EmulatedEndpoint* 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(
           absl::make_unique<rtc::Network>(endpoint->network()));
     }
   }
   return networks;
 }

 EmulatedNetworkStats EndpointsContainer::GetStats() const {
   EmulatedNetworkStats stats;
   for (auto* endpoint : endpoints_) {
     EmulatedNetworkStats endpoint_stats = endpoint->stats();
     stats.packets_sent += endpoint_stats.packets_sent;
     stats.bytes_sent += endpoint_stats.bytes_sent;
     stats.packets_received += endpoint_stats.packets_received;
     stats.bytes_received += endpoint_stats.bytes_received;
     stats.packets_dropped += endpoint_stats.packets_dropped;
     stats.bytes_dropped += endpoint_stats.bytes_dropped;
     if (stats.first_packet_received_time >
         endpoint_stats.first_packet_received_time) {
       stats.first_packet_received_time =
           endpoint_stats.first_packet_received_time;
       stats.first_received_packet_size =
           endpoint_stats.first_received_packet_size;
     }
     if (stats.first_packet_sent_time > endpoint_stats.first_packet_sent_time) {
       stats.first_packet_sent_time = endpoint_stats.first_packet_sent_time;
       stats.first_sent_packet_size = endpoint_stats.first_sent_packet_size;
     }
     if (stats.last_packet_received_time.IsInfinite() ||
         stats.last_packet_received_time <
             endpoint_stats.last_packet_received_time) {
       stats.last_packet_received_time =
           endpoint_stats.last_packet_received_time;
     }
     if (stats.last_packet_sent_time.IsInfinite() ||
         stats.last_packet_sent_time < endpoint_stats.last_packet_sent_time) {
       stats.last_packet_sent_time = endpoint_stats.last_packet_sent_time;
     }
   }
   return stats;
 }

 }  // 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/scenario/network/network_emulation.h"

	#include <limits>
	#include <memory>

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

	namespace webrtc {

	EmulatedIpPacket::EmulatedIpPacket(const rtc::SocketAddress& from,
	const rtc::SocketAddress& to,
	rtc::CopyOnWriteBuffer data,
	Timestamp arrival_time)
	: from(from),
	to(to),
	data(data),
	arrival_time(arrival_time) {}

	void LinkEmulation::OnPacketReceived(EmulatedIpPacket packet) {
	struct Closure {
	void operator()() {
	RTC_DCHECK_RUN_ON(link->task_queue_);
	link->HandlePacketReceived(std::move(packet));
	}
	LinkEmulation* link;
	EmulatedIpPacket packet;
	};
	task_queue_->PostTask(Closure{this, std::move(packet)});
	}

	void LinkEmulation::HandlePacketReceived(EmulatedIpPacket packet) {
	uint64_t packet_id = next_packet_id_++;
	bool sent = network_behavior_->EnqueuePacket(
	PacketInFlightInfo(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 = Timestamp::us(clock_->TimeInMicroseconds());
	process_task_ = RepeatingTaskHandle::DelayedStart(
	task_queue_->Get(),
	std::max(TimeDelta::Zero(), Timestamp::us(*next_time_us) - current_time),
	[this]() {
	RTC_DCHECK_RUN_ON(task_queue_);
	Timestamp current_time = Timestamp::us(clock_->TimeInMicroseconds());
	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::us(*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::us(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_);
	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(
	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(rtc::IPAddress dest_ip) {
	RTC_DCHECK_RUN_ON(task_queue_);
	routing_.erase(dest_ip);
	}

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

	EmulatedNetworkNode::~EmulatedNetworkNode() = default;

	EmulatedEndpoint::EmulatedEndpoint(uint64_t id,
	const rtc::IPAddress& ip,
	bool is_enabled,
	rtc::TaskQueue* task_queue,
	Clock* clock)
	: id_(id),
	peer_local_addr_(ip),
	is_enabled_(is_enabled),
	clock_(clock),
	task_queue_(task_queue),
	router_(task_queue_),
	next_port_(kFirstEphemeralPort) {
	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_ = absl::make_unique<rtc::Network>(
	ip.ToString(), "Endpoint id=" + std::to_string(id_), prefix,
	prefix_length, rtc::AdapterType::ADAPTER_TYPE_UNKNOWN);
	network_->AddIP(ip);

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

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

	void EmulatedEndpoint::SendPacket(const rtc::SocketAddress& from,
	const rtc::SocketAddress& to,
	rtc::CopyOnWriteBuffer packet) {
	RTC_CHECK(from.ipaddr() == peer_local_addr_);
	struct Closure {
	void operator()() {
	endpoint->UpdateSendStats(packet);
	endpoint->router_.OnPacketReceived(std::move(packet));
	}
	EmulatedEndpoint* endpoint;
	EmulatedIpPacket packet;
	};
	task_queue_->PostTask(Closure{
	this, EmulatedIpPacket(from, to, std::move(packet),
	Timestamp::us(clock_->TimeInMicroseconds()))});
	}

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

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

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

	void EmulatedEndpoint::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_);
	UpdateReceiveStats(packet);
	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_.packets_dropped++;
	stats_.bytes_dropped += DataSize::bytes(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 EmulatedEndpoint::Enable() {
	RTC_DCHECK_RUN_ON(&enabled_state_checker_);
	RTC_CHECK(!is_enabled_);
	is_enabled_ = true;
	}

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

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

	EmulatedNetworkStats EmulatedEndpoint::stats() {
	RTC_DCHECK_RUN_ON(task_queue_);
	return stats_;
	}

	void EmulatedEndpoint::UpdateSendStats(const EmulatedIpPacket& packet) {
	RTC_DCHECK_RUN_ON(task_queue_);
	Timestamp current_time = Timestamp::us(clock_->TimeInMicroseconds());
	if (stats_.first_packet_sent_time.IsInfinite()) {
	stats_.first_packet_sent_time = current_time;
	stats_.first_sent_packet_size = DataSize::bytes(packet.size());
	}
	stats_.last_packet_sent_time = current_time;
	stats_.packets_sent++;
	stats_.bytes_sent += DataSize::bytes(packet.size());
	}

	void EmulatedEndpoint::UpdateReceiveStats(const EmulatedIpPacket& packet) {
	RTC_DCHECK_RUN_ON(task_queue_);
	Timestamp current_time = Timestamp::us(clock_->TimeInMicroseconds());
	if (stats_.first_packet_received_time.IsInfinite()) {
	stats_.first_packet_received_time = current_time;
	stats_.first_received_packet_size = DataSize::bytes(packet.size());
	}
	stats_.last_packet_received_time = current_time;
	stats_.packets_received++;
	stats_.bytes_received += DataSize::bytes(packet.size());
	}

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

	EmulatedEndpoint* 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(EmulatedEndpoint* 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(
	absl::make_unique<rtc::Network>(endpoint->network()));
	}
	}
	return networks;
	}

	EmulatedNetworkStats EndpointsContainer::GetStats() const {
	EmulatedNetworkStats stats;
	for (auto* endpoint : endpoints_) {
	EmulatedNetworkStats endpoint_stats = endpoint->stats();
	stats.packets_sent += endpoint_stats.packets_sent;
	stats.bytes_sent += endpoint_stats.bytes_sent;
	stats.packets_received += endpoint_stats.packets_received;
	stats.bytes_received += endpoint_stats.bytes_received;
	stats.packets_dropped += endpoint_stats.packets_dropped;
	stats.bytes_dropped += endpoint_stats.bytes_dropped;
	if (stats.first_packet_received_time >
	endpoint_stats.first_packet_received_time) {
	stats.first_packet_received_time =
	endpoint_stats.first_packet_received_time;
	stats.first_received_packet_size =
	endpoint_stats.first_received_packet_size;
	}
	if (stats.first_packet_sent_time > endpoint_stats.first_packet_sent_time) {
	stats.first_packet_sent_time = endpoint_stats.first_packet_sent_time;
	stats.first_sent_packet_size = endpoint_stats.first_sent_packet_size;
	}
	if (stats.last_packet_received_time.IsInfinite() \|\|
	stats.last_packet_received_time <
	endpoint_stats.last_packet_received_time) {
	stats.last_packet_received_time =
	endpoint_stats.last_packet_received_time;
	}
	if (stats.last_packet_sent_time.IsInfinite() \|\|
	stats.last_packet_sent_time < endpoint_stats.last_packet_sent_time) {
	stats.last_packet_sent_time = endpoint_stats.last_packet_sent_time;
	}
	}
	return stats;
	}

	} // namespace webrtc