session_impl.hpp

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			{ m_dht_proxy = s; }
			proxy_settings const& dht_proxy() const
			{ return m_dht_proxy; }
#endif

#ifdef TORRENT_STATS
			void log_buffer_usage()
			{
				int send_buffer_capacity = 0;
				int used_send_buffer = 0;
				for (connection_map::const_iterator i = m_connections.begin()
					, end(m_connections.end()); i != end; ++i)
				{
					send_buffer_capacity += (*i)->send_buffer_capacity();
					used_send_buffer += (*i)->send_buffer_size();
				}
				TORRENT_ASSERT(send_buffer_capacity >= used_send_buffer);
				m_buffer_usage_logger << log_time() << " send_buffer_size: " << send_buffer_capacity << std::endl;
				m_buffer_usage_logger << log_time() << " used_send_buffer: " << used_send_buffer << std::endl;
				m_buffer_usage_logger << log_time() << " send_buffer_utilization: "
					<< (used_send_buffer * 100.f / send_buffer_capacity) << std::endl;
			}
#endif
			void start_lsd();
			void start_natpmp();
			void start_upnp();

			void stop_lsd();
			void stop_natpmp();
			void stop_upnp();

			// handles delayed alerts
			alert_manager m_alerts;

			std::pair<char*, int> allocate_buffer(int size);
			void free_buffer(char* buf, int size);
			void free_disk_buffer(char* buf);
			
			address m_external_address;

//		private:

			void on_lsd_peer(tcp::endpoint peer, sha1_hash const& ih);

			// this pool is used to allocate and recycle send
			// buffers from.
			boost::pool<> m_send_buffers;
			boost::mutex m_send_buffer_mutex;

			// the file pool that all storages in this session's
			// torrents uses. It sets a limit on the number of
			// open files by this session.
			// file pool must be destructed after the torrents
			// since they will still have references to it
			// when they are destructed.
			file_pool m_files;

			// handles disk io requests asynchronously
			// peers have pointers into the disk buffer
			// pool, and must be destructed before this
			// object. The disk thread relies on the file
			// pool object, and must be destructed before
			// m_files.
			disk_io_thread m_disk_thread;

			// this is where all active sockets are stored.
			// the selector can sleep while there's no activity on
			// them
			io_service m_io_service;
			asio::strand m_strand;

			// this is a list of half-open tcp connections
			// (only outgoing connections)
			// this has to be one of the last
			// members to be destructed
			connection_queue m_half_open;

			// the bandwidth manager is responsible for
			// handing out bandwidth to connections that
			// asks for it, it can also throttle the
			// rate.
			bandwidth_manager<peer_connection, torrent> m_download_channel;
			bandwidth_manager<peer_connection, torrent> m_upload_channel;

			bandwidth_manager<peer_connection, torrent>* m_bandwidth_manager[2];

			tracker_manager m_tracker_manager;
			torrent_map m_torrents;

			// this maps sockets to their peer_connection
			// object. It is the complete list of all connected
			// peers.
			connection_map m_connections;
			
			// filters incoming connections
			ip_filter m_ip_filter;

			// filters outgoing connections
			port_filter m_port_filter;
			
			// the peer id that is generated at the start of the session
			peer_id m_peer_id;

			// the key is an id that is used to identify the
			// client with the tracker only. It is randomized
			// at startup
			int m_key;

			// the number of retries we make when binding the
			// listen socket. For each retry the port number
			// is incremented by one
			int m_listen_port_retries;

			// the ip-address of the interface
			// we are supposed to listen on.
			// if the ip is set to zero, it means
			// that we should let the os decide which
			// interface to listen on
			tcp::endpoint m_listen_interface;

			// if we're listening on an IPv6 interface
			// this is one of the non local IPv6 interfaces
			// on this machine
			tcp::endpoint m_ipv6_interface;
			
			struct listen_socket_t
			{
				listen_socket_t(): external_port(0) {}
				// this is typically set to the same as the local
				// listen port. In case a NAT port forward was
				// successfully opened, this will be set to the
				// port that is open on the external (NAT) interface
				// on the NAT box itself. This is the port that has
				// to be published to peers, since this is the port
				// the client is reachable through.
				int external_port;

				// the actual socket
				boost::shared_ptr<socket_acceptor> sock;
			};
			// since we might be listening on multiple interfaces
			// we might need more than one listen socket
			std::list<listen_socket_t> m_listen_sockets;

			listen_socket_t setup_listener(tcp::endpoint ep, int retries, bool v6_only = false);

			// the settings for the client
			session_settings m_settings;
			// the proxy settings for different
			// kinds of connections
			proxy_settings m_peer_proxy;
			proxy_settings m_web_seed_proxy;
			proxy_settings m_tracker_proxy;
#ifndef TORRENT_DISABLE_DHT
			proxy_settings m_dht_proxy;
#endif

			// set to true when the session object
			// is being destructed and the thread
			// should exit
			volatile bool m_abort;

			int m_max_uploads;
			int m_max_connections;

			// the number of unchoked peers
			int m_num_unchoked;

			// this is initialized to the unchoke_interval
			// session_setting and decreased every second.
			// when it reaches zero, it is reset to the
			// unchoke_interval and the unchoke set is
			// recomputed.
			int m_unchoke_time_scaler;

			// works like unchoke_time_scaler but it
			// is only decresed when the unchoke set
			// is recomputed, and when it reaches zero,
			// the optimistic unchoke is moved to another peer.
			int m_optimistic_unchoke_time_scaler;

			// works like unchoke_time_scaler. Each time
			// it reaches 0, and all the connections are
			// used, the worst connection will be disconnected
			// from the torrent with the most peers
			int m_disconnect_time_scaler;

			// statistics gathered from all torrents.
			stat m_stat;

			// is false by default and set to true when
			// the first incoming connection is established
			// this is used to know if the client is behind
			// NAT or not.
			bool m_incoming_connection;
			
			void second_tick(asio::error_code const& e);
			ptime m_last_tick;

#ifndef TORRENT_DISABLE_DHT
			boost::intrusive_ptr<dht::dht_tracker> m_dht;
			dht_settings m_dht_settings;
			// if this is set to true, the dht listen port
			// will be set to the same as the tcp listen port
			// and will be synchronlized with it as it changes
			// it defaults to true
			bool m_dht_same_port;
			
			// see m_external_listen_port. This is the same
			// but for the udp port used by the DHT.
			int m_external_udp_port;
#endif

#ifndef TORRENT_DISABLE_ENCRYPTION
			pe_settings m_pe_settings;
#endif

			boost::intrusive_ptr<natpmp> m_natpmp;
			boost::intrusive_ptr<upnp> m_upnp;
			boost::intrusive_ptr<lsd> m_lsd;

			// the timer used to fire the second_tick
			deadline_timer m_timer;

			// the index of the torrent that will be offered to
			// connect to a peer next time second_tick is called.
			// This implements a round robin.
			int m_next_connect_torrent;
#ifndef NDEBUG
			void check_invariant() const;
#endif

#ifdef TORRENT_STATS
			// logger used to write bandwidth usage statistics
			std::ofstream m_stats_logger;
			int m_second_counter;
			// used to log send buffer usage statistics
			std::ofstream m_buffer_usage_logger;
			// the number of send buffers that are allocated
			int m_buffer_allocations;
#endif
#if defined(TORRENT_VERBOSE_LOGGING) || defined(TORRENT_LOGGING)
			boost::shared_ptr<logger> create_log(std::string const& name
				, int instance, bool append = true);
			
			// this list of tracker loggers serves as tracker_callbacks when
			// shutting down. This list is just here to keep them alive during
			// whe shutting down process
			std::list<boost::shared_ptr<tracker_logger> > m_tracker_loggers;

			fs::path m_logpath;
		public:
			boost::shared_ptr<logger> m_logger;
		private:
#endif

#ifndef TORRENT_DISABLE_EXTENSIONS
			typedef std::list<boost::function<boost::shared_ptr<
				torrent_plugin>(torrent*, void*)> > extension_list_t;

			extension_list_t m_extensions;
#endif

			// data shared between the main thread
			// and the checker thread
			checker_impl m_checker_impl;

			// the main working thread
			boost::scoped_ptr<boost::thread> m_thread;

			// the thread that calls initialize_pieces()
			// on all torrents before they start downloading
			boost::scoped_ptr<boost::thread> m_checker_thread;
		};
		
#if defined(TORRENT_LOGGING) || defined(TORRENT_VERBOSE_LOGGING)
		struct tracker_logger : request_callback
		{
			tracker_logger(session_impl& ses): m_ses(ses) {}
			void tracker_warning(std::string const& str)
			{
				debug_log("*** tracker warning: " + str);
			}

			void tracker_response(tracker_request const&
				, std::vector<peer_entry>& peers
				, int interval
				, int complete
				, int incomplete)
			{
				std::stringstream s;
				s << "TRACKER RESPONSE:\n"
					"interval: " << interval << "\n"
					"peers:\n";
				for (std::vector<peer_entry>::const_iterator i = peers.begin();
					i != peers.end(); ++i)
				{
					s << "  " << std::setfill(' ') << std::setw(16) << i->ip
						<< " " << std::setw(5) << std::dec << i->port << "  ";
					if (!i->pid.is_all_zeros()) s << " " << i->pid;
					s << "\n";
				}
				debug_log(s.str());
			}

			void tracker_request_timed_out(
				tracker_request const&)
			{
				debug_log("*** tracker timed out");
			}

			void tracker_request_error(
				tracker_request const&
				, int response_code
				, const std::string& str)
			{
				debug_log(std::string("*** tracker error: ")
					+ boost::lexical_cast<std::string>(response_code) + ": "
					+ str);
			}
			
			void debug_log(const std::string& line)
			{
				(*m_ses.m_logger) << time_now_string() << " " << line << "\n";
			}
			session_impl& m_ses;
		};
#endif

	}
}


#endif