p2p/base/turn_server.h - src - Git at Google

 /*
  *  Copyright 2012 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_BASE_TURN_SERVER_H_
 #define P2P_BASE_TURN_SERVER_H_

 #include <list>
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>

 #include "absl/strings/string_view.h"
 #include "api/sequence_checker.h"
 #include "p2p/base/port_interface.h"
 #include "rtc_base/async_packet_socket.h"
 #include "rtc_base/socket_address.h"
 #include "rtc_base/ssl_adapter.h"
 #include "rtc_base/third_party/sigslot/sigslot.h"
 #include "rtc_base/thread.h"

 namespace rtc {
 class ByteBufferWriter;
 class PacketSocketFactory;
 }  // namespace rtc

 namespace cricket {

 class StunMessage;
 class TurnMessage;
 class TurnServer;

 // The default server port for TURN, as specified in RFC5766.
 const int TURN_SERVER_PORT = 3478;

 // Encapsulates the client's connection to the server.
 class TurnServerConnection {
  public:
   TurnServerConnection() : proto_(PROTO_UDP), socket_(NULL) {}
   TurnServerConnection(const rtc::SocketAddress& src,
                        ProtocolType proto,
                        rtc::AsyncPacketSocket* socket);
   const rtc::SocketAddress& src() const { return src_; }
   rtc::AsyncPacketSocket* socket() { return socket_; }
   bool operator==(const TurnServerConnection& t) const;
   bool operator<(const TurnServerConnection& t) const;
   std::string ToString() const;

  private:
   rtc::SocketAddress src_;
   rtc::SocketAddress dst_;
   cricket::ProtocolType proto_;
   rtc::AsyncPacketSocket* socket_;
 };

 // Encapsulates a TURN allocation.
 // The object is created when an allocation request is received, and then
 // handles TURN messages (via HandleTurnMessage) and channel data messages
 // (via HandleChannelData) for this allocation when received by the server.
 // The object self-deletes and informs the server if its lifetime timer expires.
 class TurnServerAllocation : public rtc::MessageHandlerAutoCleanup,
                              public sigslot::has_slots<> {
  public:
   TurnServerAllocation(TurnServer* server_,
                        rtc::Thread* thread,
                        const TurnServerConnection& conn,
                        rtc::AsyncPacketSocket* server_socket,
                        absl::string_view key);
   ~TurnServerAllocation() override;

   TurnServerConnection* conn() { return &conn_; }
   const std::string& key() const { return key_; }
   const std::string& transaction_id() const { return transaction_id_; }
   const std::string& username() const { return username_; }
   const std::string& last_nonce() const { return last_nonce_; }
   void set_last_nonce(absl::string_view nonce) {
     last_nonce_ = std::string(nonce);
   }

   std::string ToString() const;

   void HandleTurnMessage(const TurnMessage* msg);
   void HandleChannelData(const char* data, size_t size);

   sigslot::signal1<TurnServerAllocation*> SignalDestroyed;

  private:
   class Channel;
   class Permission;
   typedef std::list<Permission*> PermissionList;
   typedef std::list<Channel*> ChannelList;

   void HandleAllocateRequest(const TurnMessage* msg);
   void HandleRefreshRequest(const TurnMessage* msg);
   void HandleSendIndication(const TurnMessage* msg);
   void HandleCreatePermissionRequest(const TurnMessage* msg);
   void HandleChannelBindRequest(const TurnMessage* msg);

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

   static int ComputeLifetime(const TurnMessage& msg);
   bool HasPermission(const rtc::IPAddress& addr);
   void AddPermission(const rtc::IPAddress& addr);
   Permission* FindPermission(const rtc::IPAddress& addr) const;
   Channel* FindChannel(int channel_id) const;
   Channel* FindChannel(const rtc::SocketAddress& addr) const;

   void SendResponse(TurnMessage* msg);
   void SendBadRequestResponse(const TurnMessage* req);
   void SendErrorResponse(const TurnMessage* req,
                          int code,
                          absl::string_view reason);
   void SendExternal(const void* data,
                     size_t size,
                     const rtc::SocketAddress& peer);

   void OnPermissionDestroyed(Permission* perm);
   void OnChannelDestroyed(Channel* channel);
   void OnMessage(rtc::Message* msg) override;

   TurnServer* const server_;
   rtc::Thread* const thread_;
   TurnServerConnection conn_;
   std::unique_ptr<rtc::AsyncPacketSocket> external_socket_;
   std::string key_;
   std::string transaction_id_;
   std::string username_;
   std::string last_nonce_;
   PermissionList perms_;
   ChannelList channels_;
 };

 // An interface through which the MD5 credential hash can be retrieved.
 class TurnAuthInterface {
  public:
   // Gets HA1 for the specified user and realm.
   // HA1 = MD5(A1) = MD5(username:realm:password).
   // Return true if the given username and realm are valid, or false if not.
   virtual bool GetKey(absl::string_view username,
                       absl::string_view realm,
                       std::string* key) = 0;
   virtual ~TurnAuthInterface() = default;
 };

 // An interface enables Turn Server to control redirection behavior.
 class TurnRedirectInterface {
  public:
   virtual bool ShouldRedirect(const rtc::SocketAddress& address,
                               rtc::SocketAddress* out) = 0;
   virtual ~TurnRedirectInterface() {}
 };

 class StunMessageObserver {
  public:
   virtual void ReceivedMessage(const TurnMessage* msg) = 0;
   virtual void ReceivedChannelData(const char* data, size_t size) = 0;
   virtual ~StunMessageObserver() {}
 };

 // The core TURN server class. Give it a socket to listen on via
 // AddInternalServerSocket, and a factory to create external sockets via
 // SetExternalSocketFactory, and it's ready to go.
 // Not yet wired up: TCP support.
 class TurnServer : public sigslot::has_slots<> {
  public:
   typedef std::map<TurnServerConnection, std::unique_ptr<TurnServerAllocation>>
       AllocationMap;

   explicit TurnServer(rtc::Thread* thread);
   ~TurnServer() override;

   // Gets/sets the realm value to use for the server.
   const std::string& realm() const {
     RTC_DCHECK_RUN_ON(thread_);
     return realm_;
   }
   void set_realm(absl::string_view realm) {
     RTC_DCHECK_RUN_ON(thread_);
     realm_ = std::string(realm);
   }

   // Gets/sets the value for the SOFTWARE attribute for TURN messages.
   const std::string& software() const {
     RTC_DCHECK_RUN_ON(thread_);
     return software_;
   }
   void set_software(absl::string_view software) {
     RTC_DCHECK_RUN_ON(thread_);
     software_ = std::string(software);
   }

   const AllocationMap& allocations() const {
     RTC_DCHECK_RUN_ON(thread_);
     return allocations_;
   }

   // Sets the authentication callback; does not take ownership.
   void set_auth_hook(TurnAuthInterface* auth_hook) {
     RTC_DCHECK_RUN_ON(thread_);
     auth_hook_ = auth_hook;
   }

   void set_redirect_hook(TurnRedirectInterface* redirect_hook) {
     RTC_DCHECK_RUN_ON(thread_);
     redirect_hook_ = redirect_hook;
   }

   void set_enable_otu_nonce(bool enable) {
     RTC_DCHECK_RUN_ON(thread_);
     enable_otu_nonce_ = enable;
   }

   // If set to true, reject CreatePermission requests to RFC1918 addresses.
   void set_reject_private_addresses(bool filter) {
     RTC_DCHECK_RUN_ON(thread_);
     reject_private_addresses_ = filter;
   }

   void set_enable_permission_checks(bool enable) {
     RTC_DCHECK_RUN_ON(thread_);
     enable_permission_checks_ = enable;
   }

   // Starts listening for packets from internal clients.
   void AddInternalSocket(rtc::AsyncPacketSocket* socket, ProtocolType proto);
   // Starts listening for the connections on this socket. When someone tries
   // to connect, the connection will be accepted and a new internal socket
   // will be added.
   void AddInternalServerSocket(
       rtc::Socket* socket,
       ProtocolType proto,
       std::unique_ptr<rtc::SSLAdapterFactory> ssl_adapter_factory = nullptr);
   // Specifies the factory to use for creating external sockets.
   void SetExternalSocketFactory(rtc::PacketSocketFactory* factory,
                                 const rtc::SocketAddress& address);
   // For testing only.
   std::string SetTimestampForNextNonce(int64_t timestamp) {
     RTC_DCHECK_RUN_ON(thread_);
     ts_for_next_nonce_ = timestamp;
     return GenerateNonce(timestamp);
   }

   void SetStunMessageObserver(std::unique_ptr<StunMessageObserver> observer) {
     RTC_DCHECK_RUN_ON(thread_);
     stun_message_observer_ = std::move(observer);
   }

  private:
   // All private member functions and variables should have access restricted to
   // thread_. But compile-time annotations are missing for members access from
   // TurnServerAllocation (via friend declaration), and the On* methods, which
   // are called via sigslot.
   std::string GenerateNonce(int64_t now) const RTC_RUN_ON(thread_);
   void OnInternalPacket(rtc::AsyncPacketSocket* socket,
                         const char* data,
                         size_t size,
                         const rtc::SocketAddress& address,
                         const int64_t& packet_time_us);

   void OnNewInternalConnection(rtc::Socket* socket);

   // Accept connections on this server socket.
   void AcceptConnection(rtc::Socket* server_socket) RTC_RUN_ON(thread_);
   void OnInternalSocketClose(rtc::AsyncPacketSocket* socket, int err);

   void HandleStunMessage(TurnServerConnection* conn,
                          const char* data,
                          size_t size) RTC_RUN_ON(thread_);
   void HandleBindingRequest(TurnServerConnection* conn, const StunMessage* msg)
       RTC_RUN_ON(thread_);
   void HandleAllocateRequest(TurnServerConnection* conn,
                              const TurnMessage* msg,
                              absl::string_view key) RTC_RUN_ON(thread_);

   bool GetKey(const StunMessage* msg, std::string* key) RTC_RUN_ON(thread_);
   bool CheckAuthorization(TurnServerConnection* conn,
                           StunMessage* msg,
                           const char* data,
                           size_t size,
                           absl::string_view key) RTC_RUN_ON(thread_);
   bool ValidateNonce(absl::string_view nonce) const RTC_RUN_ON(thread_);

   TurnServerAllocation* FindAllocation(TurnServerConnection* conn)
       RTC_RUN_ON(thread_);
   TurnServerAllocation* CreateAllocation(TurnServerConnection* conn,
                                          int proto,
                                          absl::string_view key)
       RTC_RUN_ON(thread_);

   void SendErrorResponse(TurnServerConnection* conn,
                          const StunMessage* req,
                          int code,
                          absl::string_view reason);

   void SendErrorResponseWithRealmAndNonce(TurnServerConnection* conn,
                                           const StunMessage* req,
                                           int code,
                                           absl::string_view reason)
       RTC_RUN_ON(thread_);

   void SendErrorResponseWithAlternateServer(TurnServerConnection* conn,
                                             const StunMessage* req,
                                             const rtc::SocketAddress& addr)
       RTC_RUN_ON(thread_);

   void SendStun(TurnServerConnection* conn, StunMessage* msg);
   void Send(TurnServerConnection* conn, const rtc::ByteBufferWriter& buf);

   void OnAllocationDestroyed(TurnServerAllocation* allocation)
       RTC_RUN_ON(thread_);
   void DestroyInternalSocket(rtc::AsyncPacketSocket* socket)
       RTC_RUN_ON(thread_);

   typedef std::map<rtc::AsyncPacketSocket*, ProtocolType> InternalSocketMap;
   struct ServerSocketInfo {
     ProtocolType proto;
     // If non-null, used to wrap accepted sockets.
     std::unique_ptr<rtc::SSLAdapterFactory> ssl_adapter_factory;
   };
   typedef std::map<rtc::Socket*, ServerSocketInfo> ServerSocketMap;

   rtc::Thread* const thread_;
   const std::string nonce_key_;
   std::string realm_ RTC_GUARDED_BY(thread_);
   std::string software_ RTC_GUARDED_BY(thread_);
   TurnAuthInterface* auth_hook_ RTC_GUARDED_BY(thread_);
   TurnRedirectInterface* redirect_hook_ RTC_GUARDED_BY(thread_);
   // otu - one-time-use. Server will respond with 438 if it's
   // sees the same nonce in next transaction.
   bool enable_otu_nonce_ RTC_GUARDED_BY(thread_);
   bool reject_private_addresses_ = false;
   // Check for permission when receiving an external packet.
   bool enable_permission_checks_ = true;

   InternalSocketMap server_sockets_ RTC_GUARDED_BY(thread_);
   ServerSocketMap server_listen_sockets_ RTC_GUARDED_BY(thread_);
   std::unique_ptr<rtc::PacketSocketFactory> external_socket_factory_
       RTC_GUARDED_BY(thread_);
   rtc::SocketAddress external_addr_ RTC_GUARDED_BY(thread_);

   AllocationMap allocations_ RTC_GUARDED_BY(thread_);

   // For testing only. If this is non-zero, the next NONCE will be generated
   // from this value, and it will be reset to 0 after generating the NONCE.
   int64_t ts_for_next_nonce_ RTC_GUARDED_BY(thread_) = 0;

   // For testing only. Used to observe STUN messages received.
   std::unique_ptr<StunMessageObserver> stun_message_observer_
       RTC_GUARDED_BY(thread_);

   friend class TurnServerAllocation;
 };

 }  // namespace cricket

 #endif  // P2P_BASE_TURN_SERVER_H_
	/*
	* Copyright 2012 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_BASE_TURN_SERVER_H_
	#define P2P_BASE_TURN_SERVER_H_

	#include <list>
	#include <map>
	#include <memory>
	#include <set>
	#include <string>
	#include <utility>
	#include <vector>

	#include "absl/strings/string_view.h"
	#include "api/sequence_checker.h"
	#include "p2p/base/port_interface.h"
	#include "rtc_base/async_packet_socket.h"
	#include "rtc_base/socket_address.h"
	#include "rtc_base/ssl_adapter.h"
	#include "rtc_base/third_party/sigslot/sigslot.h"
	#include "rtc_base/thread.h"

	namespace rtc {
	class ByteBufferWriter;
	class PacketSocketFactory;
	} // namespace rtc

	namespace cricket {

	class StunMessage;
	class TurnMessage;
	class TurnServer;

	// The default server port for TURN, as specified in RFC5766.
	const int TURN_SERVER_PORT = 3478;

	// Encapsulates the client's connection to the server.
	class TurnServerConnection {
	public:
	TurnServerConnection() : proto_(PROTO_UDP), socket_(NULL) {}
	TurnServerConnection(const rtc::SocketAddress& src,
	ProtocolType proto,
	rtc::AsyncPacketSocket* socket);
	const rtc::SocketAddress& src() const { return src_; }
	rtc::AsyncPacketSocket* socket() { return socket_; }
	bool operator==(const TurnServerConnection& t) const;
	bool operator<(const TurnServerConnection& t) const;
	std::string ToString() const;

	private:
	rtc::SocketAddress src_;
	rtc::SocketAddress dst_;
	cricket::ProtocolType proto_;
	rtc::AsyncPacketSocket* socket_;
	};

	// Encapsulates a TURN allocation.
	// The object is created when an allocation request is received, and then
	// handles TURN messages (via HandleTurnMessage) and channel data messages
	// (via HandleChannelData) for this allocation when received by the server.
	// The object self-deletes and informs the server if its lifetime timer expires.
	class TurnServerAllocation : public rtc::MessageHandlerAutoCleanup,
	public sigslot::has_slots<> {
	public:
	TurnServerAllocation(TurnServer* server_,
	rtc::Thread* thread,
	const TurnServerConnection& conn,
	rtc::AsyncPacketSocket* server_socket,
	absl::string_view key);
	~TurnServerAllocation() override;

	TurnServerConnection* conn() { return &conn_; }
	const std::string& key() const { return key_; }
	const std::string& transaction_id() const { return transaction_id_; }
	const std::string& username() const { return username_; }
	const std::string& last_nonce() const { return last_nonce_; }
	void set_last_nonce(absl::string_view nonce) {
	last_nonce_ = std::string(nonce);
	}

	std::string ToString() const;

	void HandleTurnMessage(const TurnMessage* msg);
	void HandleChannelData(const char* data, size_t size);

	sigslot::signal1<TurnServerAllocation*> SignalDestroyed;

	private:
	class Channel;
	class Permission;
	typedef std::list<Permission*> PermissionList;
	typedef std::list<Channel*> ChannelList;

	void HandleAllocateRequest(const TurnMessage* msg);
	void HandleRefreshRequest(const TurnMessage* msg);
	void HandleSendIndication(const TurnMessage* msg);
	void HandleCreatePermissionRequest(const TurnMessage* msg);
	void HandleChannelBindRequest(const TurnMessage* msg);

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

	static int ComputeLifetime(const TurnMessage& msg);
	bool HasPermission(const rtc::IPAddress& addr);
	void AddPermission(const rtc::IPAddress& addr);
	Permission* FindPermission(const rtc::IPAddress& addr) const;
	Channel* FindChannel(int channel_id) const;
	Channel* FindChannel(const rtc::SocketAddress& addr) const;

	void SendResponse(TurnMessage* msg);
	void SendBadRequestResponse(const TurnMessage* req);
	void SendErrorResponse(const TurnMessage* req,
	int code,
	absl::string_view reason);
	void SendExternal(const void* data,
	size_t size,
	const rtc::SocketAddress& peer);

	void OnPermissionDestroyed(Permission* perm);
	void OnChannelDestroyed(Channel* channel);
	void OnMessage(rtc::Message* msg) override;

	TurnServer* const server_;
	rtc::Thread* const thread_;
	TurnServerConnection conn_;
	std::unique_ptr<rtc::AsyncPacketSocket> external_socket_;
	std::string key_;
	std::string transaction_id_;
	std::string username_;
	std::string last_nonce_;
	PermissionList perms_;
	ChannelList channels_;
	};

	// An interface through which the MD5 credential hash can be retrieved.
	class TurnAuthInterface {
	public:
	// Gets HA1 for the specified user and realm.
	// HA1 = MD5(A1) = MD5(username:realm:password).
	// Return true if the given username and realm are valid, or false if not.
	virtual bool GetKey(absl::string_view username,
	absl::string_view realm,
	std::string* key) = 0;
	virtual ~TurnAuthInterface() = default;
	};

	// An interface enables Turn Server to control redirection behavior.
	class TurnRedirectInterface {
	public:
	virtual bool ShouldRedirect(const rtc::SocketAddress& address,
	rtc::SocketAddress* out) = 0;
	virtual ~TurnRedirectInterface() {}
	};

	class StunMessageObserver {
	public:
	virtual void ReceivedMessage(const TurnMessage* msg) = 0;
	virtual void ReceivedChannelData(const char* data, size_t size) = 0;
	virtual ~StunMessageObserver() {}
	};

	// The core TURN server class. Give it a socket to listen on via
	// AddInternalServerSocket, and a factory to create external sockets via
	// SetExternalSocketFactory, and it's ready to go.
	// Not yet wired up: TCP support.
	class TurnServer : public sigslot::has_slots<> {
	public:
	typedef std::map<TurnServerConnection, std::unique_ptr<TurnServerAllocation>>
	AllocationMap;

	explicit TurnServer(rtc::Thread* thread);
	~TurnServer() override;

	// Gets/sets the realm value to use for the server.
	const std::string& realm() const {
	RTC_DCHECK_RUN_ON(thread_);
	return realm_;
	}
	void set_realm(absl::string_view realm) {
	RTC_DCHECK_RUN_ON(thread_);
	realm_ = std::string(realm);
	}

	// Gets/sets the value for the SOFTWARE attribute for TURN messages.
	const std::string& software() const {
	RTC_DCHECK_RUN_ON(thread_);
	return software_;
	}
	void set_software(absl::string_view software) {
	RTC_DCHECK_RUN_ON(thread_);
	software_ = std::string(software);
	}

	const AllocationMap& allocations() const {
	RTC_DCHECK_RUN_ON(thread_);
	return allocations_;
	}

	// Sets the authentication callback; does not take ownership.
	void set_auth_hook(TurnAuthInterface* auth_hook) {
	RTC_DCHECK_RUN_ON(thread_);
	auth_hook_ = auth_hook;
	}

	void set_redirect_hook(TurnRedirectInterface* redirect_hook) {
	RTC_DCHECK_RUN_ON(thread_);
	redirect_hook_ = redirect_hook;
	}

	void set_enable_otu_nonce(bool enable) {
	RTC_DCHECK_RUN_ON(thread_);
	enable_otu_nonce_ = enable;
	}

	// If set to true, reject CreatePermission requests to RFC1918 addresses.
	void set_reject_private_addresses(bool filter) {
	RTC_DCHECK_RUN_ON(thread_);
	reject_private_addresses_ = filter;
	}

	void set_enable_permission_checks(bool enable) {
	RTC_DCHECK_RUN_ON(thread_);
	enable_permission_checks_ = enable;
	}

	// Starts listening for packets from internal clients.
	void AddInternalSocket(rtc::AsyncPacketSocket* socket, ProtocolType proto);
	// Starts listening for the connections on this socket. When someone tries
	// to connect, the connection will be accepted and a new internal socket
	// will be added.
	void AddInternalServerSocket(
	rtc::Socket* socket,
	ProtocolType proto,
	std::unique_ptr<rtc::SSLAdapterFactory> ssl_adapter_factory = nullptr);
	// Specifies the factory to use for creating external sockets.
	void SetExternalSocketFactory(rtc::PacketSocketFactory* factory,
	const rtc::SocketAddress& address);
	// For testing only.
	std::string SetTimestampForNextNonce(int64_t timestamp) {
	RTC_DCHECK_RUN_ON(thread_);
	ts_for_next_nonce_ = timestamp;
	return GenerateNonce(timestamp);
	}

	void SetStunMessageObserver(std::unique_ptr<StunMessageObserver> observer) {
	RTC_DCHECK_RUN_ON(thread_);
	stun_message_observer_ = std::move(observer);
	}

	private:
	// All private member functions and variables should have access restricted to
	// thread_. But compile-time annotations are missing for members access from
	// TurnServerAllocation (via friend declaration), and the On* methods, which
	// are called via sigslot.
	std::string GenerateNonce(int64_t now) const RTC_RUN_ON(thread_);
	void OnInternalPacket(rtc::AsyncPacketSocket* socket,
	const char* data,
	size_t size,
	const rtc::SocketAddress& address,
	const int64_t& packet_time_us);

	void OnNewInternalConnection(rtc::Socket* socket);

	// Accept connections on this server socket.
	void AcceptConnection(rtc::Socket* server_socket) RTC_RUN_ON(thread_);
	void OnInternalSocketClose(rtc::AsyncPacketSocket* socket, int err);

	void HandleStunMessage(TurnServerConnection* conn,
	const char* data,
	size_t size) RTC_RUN_ON(thread_);
	void HandleBindingRequest(TurnServerConnection* conn, const StunMessage* msg)
	RTC_RUN_ON(thread_);
	void HandleAllocateRequest(TurnServerConnection* conn,
	const TurnMessage* msg,
	absl::string_view key) RTC_RUN_ON(thread_);

	bool GetKey(const StunMessage* msg, std::string* key) RTC_RUN_ON(thread_);
	bool CheckAuthorization(TurnServerConnection* conn,
	StunMessage* msg,
	const char* data,
	size_t size,
	absl::string_view key) RTC_RUN_ON(thread_);
	bool ValidateNonce(absl::string_view nonce) const RTC_RUN_ON(thread_);

	TurnServerAllocation* FindAllocation(TurnServerConnection* conn)
	RTC_RUN_ON(thread_);
	TurnServerAllocation* CreateAllocation(TurnServerConnection* conn,
	int proto,
	absl::string_view key)
	RTC_RUN_ON(thread_);

	void SendErrorResponse(TurnServerConnection* conn,
	const StunMessage* req,
	int code,
	absl::string_view reason);

	void SendErrorResponseWithRealmAndNonce(TurnServerConnection* conn,
	const StunMessage* req,
	int code,
	absl::string_view reason)
	RTC_RUN_ON(thread_);

	void SendErrorResponseWithAlternateServer(TurnServerConnection* conn,
	const StunMessage* req,
	const rtc::SocketAddress& addr)
	RTC_RUN_ON(thread_);

	void SendStun(TurnServerConnection* conn, StunMessage* msg);
	void Send(TurnServerConnection* conn, const rtc::ByteBufferWriter& buf);

	void OnAllocationDestroyed(TurnServerAllocation* allocation)
	RTC_RUN_ON(thread_);
	void DestroyInternalSocket(rtc::AsyncPacketSocket* socket)
	RTC_RUN_ON(thread_);

	typedef std::map<rtc::AsyncPacketSocket*, ProtocolType> InternalSocketMap;
	struct ServerSocketInfo {
	ProtocolType proto;
	// If non-null, used to wrap accepted sockets.
	std::unique_ptr<rtc::SSLAdapterFactory> ssl_adapter_factory;
	};
	typedef std::map<rtc::Socket*, ServerSocketInfo> ServerSocketMap;

	rtc::Thread* const thread_;
	const std::string nonce_key_;
	std::string realm_ RTC_GUARDED_BY(thread_);
	std::string software_ RTC_GUARDED_BY(thread_);
	TurnAuthInterface* auth_hook_ RTC_GUARDED_BY(thread_);
	TurnRedirectInterface* redirect_hook_ RTC_GUARDED_BY(thread_);
	// otu - one-time-use. Server will respond with 438 if it's
	// sees the same nonce in next transaction.
	bool enable_otu_nonce_ RTC_GUARDED_BY(thread_);
	bool reject_private_addresses_ = false;
	// Check for permission when receiving an external packet.
	bool enable_permission_checks_ = true;

	InternalSocketMap server_sockets_ RTC_GUARDED_BY(thread_);
	ServerSocketMap server_listen_sockets_ RTC_GUARDED_BY(thread_);
	std::unique_ptr<rtc::PacketSocketFactory> external_socket_factory_
	RTC_GUARDED_BY(thread_);
	rtc::SocketAddress external_addr_ RTC_GUARDED_BY(thread_);

	AllocationMap allocations_ RTC_GUARDED_BY(thread_);

	// For testing only. If this is non-zero, the next NONCE will be generated
	// from this value, and it will be reset to 0 after generating the NONCE.
	int64_t ts_for_next_nonce_ RTC_GUARDED_BY(thread_) = 0;

	// For testing only. Used to observe STUN messages received.
	std::unique_ptr<StunMessageObserver> stun_message_observer_
	RTC_GUARDED_BY(thread_);

	friend class TurnServerAllocation;
	};

	} // namespace cricket

	#endif // P2P_BASE_TURN_SERVER_H_