p2p/client/basic_port_allocator.h - src - Git at Google

 /*
  *  Copyright 2004 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.
  */

 #ifndef P2P_CLIENT_BASIC_PORT_ALLOCATOR_H_
 #define P2P_CLIENT_BASIC_PORT_ALLOCATOR_H_

 #include <memory>
 #include <string>
 #include <vector>

 #include "api/turn_customizer.h"
 #include "p2p/base/port_allocator.h"
 #include "p2p/client/relay_port_factory_interface.h"
 #include "p2p/client/turn_port_factory.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/network.h"
 #include "rtc_base/system/rtc_export.h"
 #include "rtc_base/task_utils/pending_task_safety_flag.h"
 #include "rtc_base/thread.h"
 #include "rtc_base/thread_annotations.h"

 namespace cricket {

 class RTC_EXPORT BasicPortAllocator : public PortAllocator {
  public:
   // note: The (optional) relay_port_factory is owned by caller
   // and must have a life time that exceeds that of BasicPortAllocator.
   BasicPortAllocator(rtc::NetworkManager* network_manager,
                      rtc::PacketSocketFactory* socket_factory,
                      webrtc::TurnCustomizer* customizer = nullptr,
                      RelayPortFactoryInterface* relay_port_factory = nullptr);
   explicit BasicPortAllocator(rtc::NetworkManager* network_manager);
   BasicPortAllocator(rtc::NetworkManager* network_manager,
                      const ServerAddresses& stun_servers);
   BasicPortAllocator(rtc::NetworkManager* network_manager,
                      rtc::PacketSocketFactory* socket_factory,
                      const ServerAddresses& stun_servers);
   ~BasicPortAllocator() override;

   // Set to kDefaultNetworkIgnoreMask by default.
   void SetNetworkIgnoreMask(int network_ignore_mask) override;
   int network_ignore_mask() const {
     CheckRunOnValidThreadIfInitialized();
     return network_ignore_mask_;
   }

   rtc::NetworkManager* network_manager() const {
     CheckRunOnValidThreadIfInitialized();
     return network_manager_;
   }

   // If socket_factory() is set to NULL each PortAllocatorSession
   // creates its own socket factory.
   rtc::PacketSocketFactory* socket_factory() {
     CheckRunOnValidThreadIfInitialized();
     return socket_factory_;
   }

   PortAllocatorSession* CreateSessionInternal(
       const std::string& content_name,
       int component,
       const std::string& ice_ufrag,
       const std::string& ice_pwd) override;

   // Convenience method that adds a TURN server to the configuration.
   void AddTurnServer(const RelayServerConfig& turn_server);

   RelayPortFactoryInterface* relay_port_factory() {
     CheckRunOnValidThreadIfInitialized();
     return relay_port_factory_;
   }

  private:
   void OnIceRegathering(PortAllocatorSession* session,
                         IceRegatheringReason reason);

   // This function makes sure that relay_port_factory_ is set properly.
   void InitRelayPortFactory(RelayPortFactoryInterface* relay_port_factory);

   bool MdnsObfuscationEnabled() const override;

   rtc::NetworkManager* network_manager_;
   rtc::PacketSocketFactory* socket_factory_;
   int network_ignore_mask_ = rtc::kDefaultNetworkIgnoreMask;

   // This is the factory being used.
   RelayPortFactoryInterface* relay_port_factory_;

   // This instance is created if caller does pass a factory.
   std::unique_ptr<RelayPortFactoryInterface> default_relay_port_factory_;
 };

 struct PortConfiguration;
 class AllocationSequence;

 enum class SessionState {
   GATHERING,  // Actively allocating ports and gathering candidates.
   CLEARED,    // Current allocation process has been stopped but may start
               // new ones.
   STOPPED     // This session has completely stopped, no new allocation
               // process will be started.
 };

 // This class is thread-compatible and assumes it's created, operated upon and
 // destroyed on the network thread.
 class RTC_EXPORT BasicPortAllocatorSession : public PortAllocatorSession {
  public:
   BasicPortAllocatorSession(BasicPortAllocator* allocator,
                             const std::string& content_name,
                             int component,
                             const std::string& ice_ufrag,
                             const std::string& ice_pwd);
   ~BasicPortAllocatorSession() override;

   virtual BasicPortAllocator* allocator();
   rtc::Thread* network_thread() { return network_thread_; }
   rtc::PacketSocketFactory* socket_factory() { return socket_factory_; }

   // If the new filter allows new types of candidates compared to the previous
   // filter, gathered candidates that were discarded because of not matching the
   // previous filter will be signaled if they match the new one.
   //
   // We do not perform any regathering since the port allocator flags decide
   // the type of candidates to gather and the candidate filter only controls the
   // signaling of candidates. As a result, with the candidate filter changed
   // alone, all newly allowed candidates for signaling should already be
   // gathered by the respective cricket::Port.
   void SetCandidateFilter(uint32_t filter) override;
   void StartGettingPorts() override;
   void StopGettingPorts() override;
   void ClearGettingPorts() override;
   bool IsGettingPorts() override;
   bool IsCleared() const override;
   bool IsStopped() const override;
   // These will all be cricket::Ports.
   std::vector<PortInterface*> ReadyPorts() const override;
   std::vector<Candidate> ReadyCandidates() const override;
   bool CandidatesAllocationDone() const override;
   void RegatherOnFailedNetworks() override;
   void GetCandidateStatsFromReadyPorts(
       CandidateStatsList* candidate_stats_list) const override;
   void SetStunKeepaliveIntervalForReadyPorts(
       const absl::optional<int>& stun_keepalive_interval) override;
   void PruneAllPorts() override;

  protected:
   void UpdateIceParametersInternal() override;

   // Starts the process of getting the port configurations.
   virtual void GetPortConfigurations();

   // Adds a port configuration that is now ready.  Once we have one for each
   // network (or a timeout occurs), we will start allocating ports.
   void ConfigReady(std::unique_ptr<PortConfiguration> config);
   // TODO(bugs.webrtc.org/12840) Remove once unused in downstream projects.
   ABSL_DEPRECATED(
       "Use ConfigReady(std::unique_ptr<PortConfiguration>) instead!")
   void ConfigReady(PortConfiguration* config);

  private:
   class PortData {
    public:
     enum State {
       STATE_INPROGRESS,  // Still gathering candidates.
       STATE_COMPLETE,    // All candidates allocated and ready for process.
       STATE_ERROR,       // Error in gathering candidates.
       STATE_PRUNED       // Pruned by higher priority ports on the same network
                          // interface. Only TURN ports may be pruned.
     };

     PortData() {}
     PortData(Port* port, AllocationSequence* seq)
         : port_(port), sequence_(seq) {}

     Port* port() const { return port_; }
     AllocationSequence* sequence() const { return sequence_; }
     bool has_pairable_candidate() const { return has_pairable_candidate_; }
     State state() const { return state_; }
     bool complete() const { return state_ == STATE_COMPLETE; }
     bool error() const { return state_ == STATE_ERROR; }
     bool pruned() const { return state_ == STATE_PRUNED; }
     bool inprogress() const { return state_ == STATE_INPROGRESS; }
     // Returns true if this port is ready to be used.
     bool ready() const {
       return has_pairable_candidate_ && state_ != STATE_ERROR &&
              state_ != STATE_PRUNED;
     }
     // Sets the state to "PRUNED" and prunes the Port.
     void Prune() {
       state_ = STATE_PRUNED;
       if (port()) {
         port()->Prune();
       }
     }
     void set_has_pairable_candidate(bool has_pairable_candidate) {
       if (has_pairable_candidate) {
         RTC_DCHECK(state_ == STATE_INPROGRESS);
       }
       has_pairable_candidate_ = has_pairable_candidate;
     }
     void set_state(State state) {
       RTC_DCHECK(state != STATE_ERROR || state_ == STATE_INPROGRESS);
       state_ = state;
     }

    private:
     Port* port_ = nullptr;
     AllocationSequence* sequence_ = nullptr;
     bool has_pairable_candidate_ = false;
     State state_ = STATE_INPROGRESS;
   };

   void OnConfigReady(std::unique_ptr<PortConfiguration> config);
   void OnConfigStop();
   void AllocatePorts();
   void OnAllocate(int allocation_epoch);
   void DoAllocate(bool disable_equivalent_phases);
   void OnNetworksChanged();
   void OnAllocationSequenceObjectsCreated();
   void DisableEquivalentPhases(rtc::Network* network,
                                PortConfiguration* config,
                                uint32_t* flags);
   void AddAllocatedPort(Port* port, AllocationSequence* seq);
   void OnCandidateReady(Port* port, const Candidate& c);
   void OnCandidateError(Port* port, const IceCandidateErrorEvent& event);
   void OnPortComplete(Port* port);
   void OnPortError(Port* port);
   void OnProtocolEnabled(AllocationSequence* seq, ProtocolType proto);
   void OnPortDestroyed(PortInterface* port);
   void MaybeSignalCandidatesAllocationDone();
   void OnPortAllocationComplete();
   PortData* FindPort(Port* port);
   std::vector<rtc::Network*> GetNetworks();
   std::vector<rtc::Network*> GetFailedNetworks();
   void Regather(const std::vector<rtc::Network*>& networks,
                 bool disable_equivalent_phases,
                 IceRegatheringReason reason);

   bool CheckCandidateFilter(const Candidate& c) const;
   bool CandidatePairable(const Candidate& c, const Port* port) const;

   std::vector<PortData*> GetUnprunedPorts(
       const std::vector<rtc::Network*>& networks);
   // Prunes ports and signal the remote side to remove the candidates that
   // were previously signaled from these ports.
   void PrunePortsAndRemoveCandidates(
       const std::vector<PortData*>& port_data_list);
   // Gets filtered and sanitized candidates generated from a port and
   // append to `candidates`.
   void GetCandidatesFromPort(const PortData& data,
                              std::vector<Candidate>* candidates) const;
   Port* GetBestTurnPortForNetwork(const std::string& network_name) const;
   // Returns true if at least one TURN port is pruned.
   bool PruneTurnPorts(Port* newly_pairable_turn_port);
   bool PruneNewlyPairableTurnPort(PortData* newly_pairable_turn_port);

   BasicPortAllocator* allocator_;
   rtc::Thread* network_thread_;
   std::unique_ptr<rtc::PacketSocketFactory> owned_socket_factory_;
   rtc::PacketSocketFactory* socket_factory_;
   bool allocation_started_;
   bool network_manager_started_;
   bool allocation_sequences_created_;
   std::vector<std::unique_ptr<PortConfiguration>> configs_;
   std::vector<AllocationSequence*> sequences_;
   std::vector<PortData> ports_;
   std::vector<IceCandidateErrorEvent> candidate_error_events_;
   uint32_t candidate_filter_ = CF_ALL;
   // Policy on how to prune turn ports, taken from the port allocator.
   webrtc::PortPrunePolicy turn_port_prune_policy_;
   SessionState state_ = SessionState::CLEARED;
   int allocation_epoch_ RTC_GUARDED_BY(network_thread_) = 0;
   webrtc::ScopedTaskSafety network_safety_;

   friend class AllocationSequence;
 };

 // Records configuration information useful in creating ports.
 // TODO(deadbeef): Rename "relay" to "turn_server" in this struct.
 struct RTC_EXPORT PortConfiguration {
   // TODO(jiayl): remove `stun_address` when Chrome is updated.
   rtc::SocketAddress stun_address;
   ServerAddresses stun_servers;
   std::string username;
   std::string password;
   bool use_turn_server_as_stun_server_disabled = false;

   typedef std::vector<RelayServerConfig> RelayList;
   RelayList relays;

   // TODO(jiayl): remove this ctor when Chrome is updated.
   PortConfiguration(const rtc::SocketAddress& stun_address,
                     const std::string& username,
                     const std::string& password);

   PortConfiguration(const ServerAddresses& stun_servers,
                     const std::string& username,
                     const std::string& password);

   // Returns addresses of both the explicitly configured STUN servers,
   // and TURN servers that should be used as STUN servers.
   ServerAddresses StunServers();

   // Adds another relay server, with the given ports and modifier, to the list.
   void AddRelay(const RelayServerConfig& config);

   // Determines whether the given relay server supports the given protocol.
   bool SupportsProtocol(const RelayServerConfig& relay,
                         ProtocolType type) const;
   bool SupportsProtocol(ProtocolType type) const;
   // Helper method returns the server addresses for the matching RelayType and
   // Protocol type.
   ServerAddresses GetRelayServerAddresses(ProtocolType type) const;
 };

 class UDPPort;
 class TurnPort;

 // Performs the allocation of ports, in a sequenced (timed) manner, for a given
 // network and IP address.
 // This class is thread-compatible.
 class AllocationSequence : public sigslot::has_slots<> {
  public:
   enum State {
     kInit,       // Initial state.
     kRunning,    // Started allocating ports.
     kStopped,    // Stopped from running.
     kCompleted,  // All ports are allocated.

     // kInit --> kRunning --> {kCompleted|kStopped}
   };
   // `port_allocation_complete_callback` is called when AllocationSequence is
   // done with allocating ports. This signal is useful when port allocation
   // fails which doesn't result in any candidates. Using this signal
   // BasicPortAllocatorSession can send its candidate discovery conclusion
   // signal. Without this signal, BasicPortAllocatorSession doesn't have any
   // event to trigger signal. This can also be achieved by starting a timer in
   // BPAS, but this is less deterministic.
   AllocationSequence(BasicPortAllocatorSession* session,
                      rtc::Network* network,
                      PortConfiguration* config,
                      uint32_t flags,
                      std::function<void()> port_allocation_complete_callback);
   void Init();
   void Clear();
   void OnNetworkFailed();

   State state() const { return state_; }
   rtc::Network* network() const { return network_; }

   bool network_failed() const { return network_failed_; }
   void set_network_failed() { network_failed_ = true; }

   // Disables the phases for a new sequence that this one already covers for an
   // equivalent network setup.
   void DisableEquivalentPhases(rtc::Network* network,
                                PortConfiguration* config,
                                uint32_t* flags);

   // Starts and stops the sequence.  When started, it will continue allocating
   // new ports on its own timed schedule.
   void Start();
   void Stop();

  protected:
   // For testing.
   void CreateTurnPort(const RelayServerConfig& config);

  private:
   typedef std::vector<ProtocolType> ProtocolList;

   void Process(int epoch);
   bool IsFlagSet(uint32_t flag) { return ((flags_ & flag) != 0); }
   void CreateUDPPorts();
   void CreateTCPPorts();
   void CreateStunPorts();
   void CreateRelayPorts();

   void OnReadPacket(rtc::AsyncPacketSocket* socket,
                     const char* data,
                     size_t size,
                     const rtc::SocketAddress& remote_addr,
                     const int64_t& packet_time_us);

   void OnPortDestroyed(PortInterface* port);

   BasicPortAllocatorSession* session_;
   bool network_failed_ = false;
   rtc::Network* network_;
   // Compared with the new best IP in DisableEquivalentPhases.
   rtc::IPAddress previous_best_ip_;
   PortConfiguration* config_;
   State state_;
   uint32_t flags_;
   ProtocolList protocols_;
   std::unique_ptr<rtc::AsyncPacketSocket> udp_socket_;
   // There will be only one udp port per AllocationSequence.
   UDPPort* udp_port_;
   std::vector<Port*> relay_ports_;
   int phase_;
   std::function<void()> port_allocation_complete_callback_;
   // This counter is sampled and passed together with tasks when tasks are
   // posted. If the sampled counter doesn't match `epoch_` on reception, the
   // posted task is ignored.
   int epoch_ = 0;
   webrtc::ScopedTaskSafety safety_;
 };

 }  // namespace cricket

 #endif  // P2P_CLIENT_BASIC_PORT_ALLOCATOR_H_
	/*
	* Copyright 2004 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.
	*/

	#ifndef P2P_CLIENT_BASIC_PORT_ALLOCATOR_H_
	#define P2P_CLIENT_BASIC_PORT_ALLOCATOR_H_

	#include <memory>
	#include <string>
	#include <vector>

	#include "api/turn_customizer.h"
	#include "p2p/base/port_allocator.h"
	#include "p2p/client/relay_port_factory_interface.h"
	#include "p2p/client/turn_port_factory.h"
	#include "rtc_base/checks.h"
	#include "rtc_base/network.h"
	#include "rtc_base/system/rtc_export.h"
	#include "rtc_base/task_utils/pending_task_safety_flag.h"
	#include "rtc_base/thread.h"
	#include "rtc_base/thread_annotations.h"

	namespace cricket {

	class RTC_EXPORT BasicPortAllocator : public PortAllocator {
	public:
	// note: The (optional) relay_port_factory is owned by caller
	// and must have a life time that exceeds that of BasicPortAllocator.
	BasicPortAllocator(rtc::NetworkManager* network_manager,
	rtc::PacketSocketFactory* socket_factory,
	webrtc::TurnCustomizer* customizer = nullptr,
	RelayPortFactoryInterface* relay_port_factory = nullptr);
	explicit BasicPortAllocator(rtc::NetworkManager* network_manager);
	BasicPortAllocator(rtc::NetworkManager* network_manager,
	const ServerAddresses& stun_servers);
	BasicPortAllocator(rtc::NetworkManager* network_manager,
	rtc::PacketSocketFactory* socket_factory,
	const ServerAddresses& stun_servers);
	~BasicPortAllocator() override;

	// Set to kDefaultNetworkIgnoreMask by default.
	void SetNetworkIgnoreMask(int network_ignore_mask) override;
	int network_ignore_mask() const {
	CheckRunOnValidThreadIfInitialized();
	return network_ignore_mask_;
	}

	rtc::NetworkManager* network_manager() const {
	CheckRunOnValidThreadIfInitialized();
	return network_manager_;
	}

	// If socket_factory() is set to NULL each PortAllocatorSession
	// creates its own socket factory.
	rtc::PacketSocketFactory* socket_factory() {
	CheckRunOnValidThreadIfInitialized();
	return socket_factory_;
	}

	PortAllocatorSession* CreateSessionInternal(
	const std::string& content_name,
	int component,
	const std::string& ice_ufrag,
	const std::string& ice_pwd) override;

	// Convenience method that adds a TURN server to the configuration.
	void AddTurnServer(const RelayServerConfig& turn_server);

	RelayPortFactoryInterface* relay_port_factory() {
	CheckRunOnValidThreadIfInitialized();
	return relay_port_factory_;
	}

	private:
	void OnIceRegathering(PortAllocatorSession* session,
	IceRegatheringReason reason);

	// This function makes sure that relay_port_factory_ is set properly.
	void InitRelayPortFactory(RelayPortFactoryInterface* relay_port_factory);

	bool MdnsObfuscationEnabled() const override;

	rtc::NetworkManager* network_manager_;
	rtc::PacketSocketFactory* socket_factory_;
	int network_ignore_mask_ = rtc::kDefaultNetworkIgnoreMask;

	// This is the factory being used.
	RelayPortFactoryInterface* relay_port_factory_;

	// This instance is created if caller does pass a factory.
	std::unique_ptr<RelayPortFactoryInterface> default_relay_port_factory_;
	};

	struct PortConfiguration;
	class AllocationSequence;

	enum class SessionState {
	GATHERING, // Actively allocating ports and gathering candidates.
	CLEARED, // Current allocation process has been stopped but may start
	// new ones.
	STOPPED // This session has completely stopped, no new allocation
	// process will be started.
	};

	// This class is thread-compatible and assumes it's created, operated upon and
	// destroyed on the network thread.
	class RTC_EXPORT BasicPortAllocatorSession : public PortAllocatorSession {
	public:
	BasicPortAllocatorSession(BasicPortAllocator* allocator,
	const std::string& content_name,
	int component,
	const std::string& ice_ufrag,
	const std::string& ice_pwd);
	~BasicPortAllocatorSession() override;

	virtual BasicPortAllocator* allocator();
	rtc::Thread* network_thread() { return network_thread_; }
	rtc::PacketSocketFactory* socket_factory() { return socket_factory_; }

	// If the new filter allows new types of candidates compared to the previous
	// filter, gathered candidates that were discarded because of not matching the
	// previous filter will be signaled if they match the new one.
	//
	// We do not perform any regathering since the port allocator flags decide
	// the type of candidates to gather and the candidate filter only controls the
	// signaling of candidates. As a result, with the candidate filter changed
	// alone, all newly allowed candidates for signaling should already be
	// gathered by the respective cricket::Port.
	void SetCandidateFilter(uint32_t filter) override;
	void StartGettingPorts() override;
	void StopGettingPorts() override;
	void ClearGettingPorts() override;
	bool IsGettingPorts() override;
	bool IsCleared() const override;
	bool IsStopped() const override;
	// These will all be cricket::Ports.
	std::vector<PortInterface*> ReadyPorts() const override;
	std::vector<Candidate> ReadyCandidates() const override;
	bool CandidatesAllocationDone() const override;
	void RegatherOnFailedNetworks() override;
	void GetCandidateStatsFromReadyPorts(
	CandidateStatsList* candidate_stats_list) const override;
	void SetStunKeepaliveIntervalForReadyPorts(
	const absl::optional<int>& stun_keepalive_interval) override;
	void PruneAllPorts() override;

	protected:
	void UpdateIceParametersInternal() override;

	// Starts the process of getting the port configurations.
	virtual void GetPortConfigurations();

	// Adds a port configuration that is now ready. Once we have one for each
	// network (or a timeout occurs), we will start allocating ports.
	void ConfigReady(std::unique_ptr<PortConfiguration> config);
	// TODO(bugs.webrtc.org/12840) Remove once unused in downstream projects.
	ABSL_DEPRECATED(
	"Use ConfigReady(std::unique_ptr<PortConfiguration>) instead!")
	void ConfigReady(PortConfiguration* config);

	private:
	class PortData {
	public:
	enum State {
	STATE_INPROGRESS, // Still gathering candidates.
	STATE_COMPLETE, // All candidates allocated and ready for process.
	STATE_ERROR, // Error in gathering candidates.
	STATE_PRUNED // Pruned by higher priority ports on the same network
	// interface. Only TURN ports may be pruned.
	};

	PortData() {}
	PortData(Port* port, AllocationSequence* seq)
	: port_(port), sequence_(seq) {}

	Port* port() const { return port_; }
	AllocationSequence* sequence() const { return sequence_; }
	bool has_pairable_candidate() const { return has_pairable_candidate_; }
	State state() const { return state_; }
	bool complete() const { return state_ == STATE_COMPLETE; }
	bool error() const { return state_ == STATE_ERROR; }
	bool pruned() const { return state_ == STATE_PRUNED; }
	bool inprogress() const { return state_ == STATE_INPROGRESS; }
	// Returns true if this port is ready to be used.
	bool ready() const {
	return has_pairable_candidate_ && state_ != STATE_ERROR &&
	state_ != STATE_PRUNED;
	}
	// Sets the state to "PRUNED" and prunes the Port.
	void Prune() {
	state_ = STATE_PRUNED;
	if (port()) {
	port()->Prune();
	}
	}
	void set_has_pairable_candidate(bool has_pairable_candidate) {
	if (has_pairable_candidate) {
	RTC_DCHECK(state_ == STATE_INPROGRESS);
	}
	has_pairable_candidate_ = has_pairable_candidate;
	}
	void set_state(State state) {
	RTC_DCHECK(state != STATE_ERROR \|\| state_ == STATE_INPROGRESS);
	state_ = state;
	}

	private:
	Port* port_ = nullptr;
	AllocationSequence* sequence_ = nullptr;
	bool has_pairable_candidate_ = false;
	State state_ = STATE_INPROGRESS;
	};

	void OnConfigReady(std::unique_ptr<PortConfiguration> config);
	void OnConfigStop();
	void AllocatePorts();
	void OnAllocate(int allocation_epoch);
	void DoAllocate(bool disable_equivalent_phases);
	void OnNetworksChanged();
	void OnAllocationSequenceObjectsCreated();
	void DisableEquivalentPhases(rtc::Network* network,
	PortConfiguration* config,
	uint32_t* flags);
	void AddAllocatedPort(Port* port, AllocationSequence* seq);
	void OnCandidateReady(Port* port, const Candidate& c);
	void OnCandidateError(Port* port, const IceCandidateErrorEvent& event);
	void OnPortComplete(Port* port);
	void OnPortError(Port* port);
	void OnProtocolEnabled(AllocationSequence* seq, ProtocolType proto);
	void OnPortDestroyed(PortInterface* port);
	void MaybeSignalCandidatesAllocationDone();
	void OnPortAllocationComplete();
	PortData* FindPort(Port* port);
	std::vector<rtc::Network*> GetNetworks();
	std::vector<rtc::Network*> GetFailedNetworks();
	void Regather(const std::vector<rtc::Network*>& networks,
	bool disable_equivalent_phases,
	IceRegatheringReason reason);

	bool CheckCandidateFilter(const Candidate& c) const;
	bool CandidatePairable(const Candidate& c, const Port* port) const;

	std::vector<PortData*> GetUnprunedPorts(
	const std::vector<rtc::Network*>& networks);
	// Prunes ports and signal the remote side to remove the candidates that
	// were previously signaled from these ports.
	void PrunePortsAndRemoveCandidates(
	const std::vector<PortData*>& port_data_list);
	// Gets filtered and sanitized candidates generated from a port and
	// append to `candidates`.
	void GetCandidatesFromPort(const PortData& data,
	std::vector<Candidate>* candidates) const;
	Port* GetBestTurnPortForNetwork(const std::string& network_name) const;
	// Returns true if at least one TURN port is pruned.
	bool PruneTurnPorts(Port* newly_pairable_turn_port);
	bool PruneNewlyPairableTurnPort(PortData* newly_pairable_turn_port);

	BasicPortAllocator* allocator_;
	rtc::Thread* network_thread_;
	std::unique_ptr<rtc::PacketSocketFactory> owned_socket_factory_;
	rtc::PacketSocketFactory* socket_factory_;
	bool allocation_started_;
	bool network_manager_started_;
	bool allocation_sequences_created_;
	std::vector<std::unique_ptr<PortConfiguration>> configs_;
	std::vector<AllocationSequence*> sequences_;
	std::vector<PortData> ports_;
	std::vector<IceCandidateErrorEvent> candidate_error_events_;
	uint32_t candidate_filter_ = CF_ALL;
	// Policy on how to prune turn ports, taken from the port allocator.
	webrtc::PortPrunePolicy turn_port_prune_policy_;
	SessionState state_ = SessionState::CLEARED;
	int allocation_epoch_ RTC_GUARDED_BY(network_thread_) = 0;
	webrtc::ScopedTaskSafety network_safety_;

	friend class AllocationSequence;
	};

	// Records configuration information useful in creating ports.
	// TODO(deadbeef): Rename "relay" to "turn_server" in this struct.
	struct RTC_EXPORT PortConfiguration {
	// TODO(jiayl): remove `stun_address` when Chrome is updated.
	rtc::SocketAddress stun_address;
	ServerAddresses stun_servers;
	std::string username;
	std::string password;
	bool use_turn_server_as_stun_server_disabled = false;

	typedef std::vector<RelayServerConfig> RelayList;
	RelayList relays;

	// TODO(jiayl): remove this ctor when Chrome is updated.
	PortConfiguration(const rtc::SocketAddress& stun_address,
	const std::string& username,
	const std::string& password);

	PortConfiguration(const ServerAddresses& stun_servers,
	const std::string& username,
	const std::string& password);

	// Returns addresses of both the explicitly configured STUN servers,
	// and TURN servers that should be used as STUN servers.
	ServerAddresses StunServers();

	// Adds another relay server, with the given ports and modifier, to the list.
	void AddRelay(const RelayServerConfig& config);

	// Determines whether the given relay server supports the given protocol.
	bool SupportsProtocol(const RelayServerConfig& relay,
	ProtocolType type) const;
	bool SupportsProtocol(ProtocolType type) const;
	// Helper method returns the server addresses for the matching RelayType and
	// Protocol type.
	ServerAddresses GetRelayServerAddresses(ProtocolType type) const;
	};

	class UDPPort;
	class TurnPort;

	// Performs the allocation of ports, in a sequenced (timed) manner, for a given
	// network and IP address.
	// This class is thread-compatible.
	class AllocationSequence : public sigslot::has_slots<> {
	public:
	enum State {
	kInit, // Initial state.
	kRunning, // Started allocating ports.
	kStopped, // Stopped from running.
	kCompleted, // All ports are allocated.

	// kInit --> kRunning --> {kCompleted\|kStopped}
	};
	// `port_allocation_complete_callback` is called when AllocationSequence is
	// done with allocating ports. This signal is useful when port allocation
	// fails which doesn't result in any candidates. Using this signal
	// BasicPortAllocatorSession can send its candidate discovery conclusion
	// signal. Without this signal, BasicPortAllocatorSession doesn't have any
	// event to trigger signal. This can also be achieved by starting a timer in
	// BPAS, but this is less deterministic.
	AllocationSequence(BasicPortAllocatorSession* session,
	rtc::Network* network,
	PortConfiguration* config,
	uint32_t flags,
	std::function<void()> port_allocation_complete_callback);
	void Init();
	void Clear();
	void OnNetworkFailed();

	State state() const { return state_; }
	rtc::Network* network() const { return network_; }

	bool network_failed() const { return network_failed_; }
	void set_network_failed() { network_failed_ = true; }

	// Disables the phases for a new sequence that this one already covers for an
	// equivalent network setup.
	void DisableEquivalentPhases(rtc::Network* network,
	PortConfiguration* config,
	uint32_t* flags);

	// Starts and stops the sequence. When started, it will continue allocating
	// new ports on its own timed schedule.
	void Start();
	void Stop();

	protected:
	// For testing.
	void CreateTurnPort(const RelayServerConfig& config);

	private:
	typedef std::vector<ProtocolType> ProtocolList;

	void Process(int epoch);
	bool IsFlagSet(uint32_t flag) { return ((flags_ & flag) != 0); }
	void CreateUDPPorts();
	void CreateTCPPorts();
	void CreateStunPorts();
	void CreateRelayPorts();

	void OnReadPacket(rtc::AsyncPacketSocket* socket,
	const char* data,
	size_t size,
	const rtc::SocketAddress& remote_addr,
	const int64_t& packet_time_us);

	void OnPortDestroyed(PortInterface* port);

	BasicPortAllocatorSession* session_;
	bool network_failed_ = false;
	rtc::Network* network_;
	// Compared with the new best IP in DisableEquivalentPhases.
	rtc::IPAddress previous_best_ip_;
	PortConfiguration* config_;
	State state_;
	uint32_t flags_;
	ProtocolList protocols_;
	std::unique_ptr<rtc::AsyncPacketSocket> udp_socket_;
	// There will be only one udp port per AllocationSequence.
	UDPPort* udp_port_;
	std::vector<Port*> relay_ports_;
	int phase_;
	std::function<void()> port_allocation_complete_callback_;
	// This counter is sampled and passed together with tasks when tasks are
	// posted. If the sampled counter doesn't match `epoch_` on reception, the
	// posted task is ignored.
	int epoch_ = 0;
	webrtc::ScopedTaskSafety safety_;
	};

	} // namespace cricket

	#endif // P2P_CLIENT_BASIC_PORT_ALLOCATOR_H_