text: /*
  
  Copyright (c) 2007-2012, Arvid Norberg
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  
      * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
      * Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in
        the documentation and/or other materials provided with the distribution.
      * Neither the name of the author nor the names of its
        contributors may be used to endorse or promote products derived
        from this software without specific prior written permission.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.
  
  */
  
  #ifndef TORRENT_UDP_SOCKET_HPP_INCLUDED
  #define TORRENT_UDP_SOCKET_HPP_INCLUDED
  
  #include "libtorrent/socket.hpp"
  #include "libtorrent/io_service.hpp"
  #include "libtorrent/error_code.hpp"
  #include "libtorrent/session_settings.hpp"
  #include "libtorrent/buffer.hpp"
  #include "libtorrent/thread.hpp"
  #include "libtorrent/deadline_timer.hpp"
  
  #include <deque>
  
  namespace libtorrent
  {
  	class connection_queue;
  
  	struct udp_socket_observer
  	{
  		// return true if the packet was handled (it won't be
  		// propagated to the next observer)
  		virtual bool incoming_packet(error_code const& ec
  			, udp::endpoint const&, char const* buf, int size) = 0;
  		virtual bool incoming_packet(error_code const& ec
  			, char const* hostname, char const* buf, int size) { return false; }
  
  		// called when the socket becomes writeable, after having
  		// failed with EWOULDBLOCK
  		virtual void writable() {}
  
  		// called every time the socket is drained of packets
  		virtual void socket_drained() {}
  	};
  
  	class udp_socket
  	{
  	public:
  		udp_socket(io_service& ios, connection_queue& cc);
  		~udp_socket();
  
  		enum flags_t { dont_drop = 1, peer_connection = 2 };
  
  		bool is_open() const
  		{
  			return m_ipv4_sock.is_open()
  #if TORRENT_USE_IPV6
  				|| m_ipv6_sock.is_open()
  #endif
  				;
  		}
  		io_service& get_io_service() { return m_ipv4_sock.get_io_service(); }
  
  		void subscribe(udp_socket_observer* o);
  		void unsubscribe(udp_socket_observer* o);
  
  		// this is only valid when using a socks5 proxy
  		void send_hostname(char const* hostname, int port, char const* p, int len, error_code& ec);
  
  		void send(udp::endpoint const& ep, char const* p, int len, error_code& ec, int flags = 0);
  		void bind(udp::endpoint const& ep, error_code& ec);
  		void close();
  		int local_port() const { return m_bind_port; }
  
  		void set_proxy_settings(proxy_settings const& ps);
  		proxy_settings const& get_proxy_settings() { return m_proxy_settings; }
  		void set_force_proxy(bool f) { m_force_proxy = f; }
  
  		bool is_closed() const { return m_abort; }
  		tcp::endpoint local_endpoint(error_code& ec) const
  		{
  			udp::endpoint ep = m_ipv4_sock.local_endpoint(ec);
  			return tcp::endpoint(ep.address(), ep.port());
  		}
  
  		void set_buf_size(int s);
  
  		template <class SocketOption>
  		void set_option(SocketOption const& opt, error_code& ec)
  		{
  			m_ipv4_sock.set_option(opt, ec);
  #if TORRENT_USE_IPV6
  			m_ipv6_sock.set_option(opt, ec);
  #endif
  		}
  
  		template <class SocketOption>
  		void get_option(SocketOption& opt, error_code& ec)
  		{
  			m_ipv4_sock.get_option(opt, ec);
  		}
  
  		udp::endpoint proxy_addr() const { return m_proxy_addr; }
  
  	protected:
  
  		struct queued_packet
  		{
  			udp::endpoint ep;
  			char* hostname;
  			buffer buf;
  			int flags;
  		};
  
  		// number of outstanding UDP socket operations
  		// using the UDP socket buffer
  		int num_outstanding() const
  		{
  			return m_v4_outstanding
  #if TORRENT_USE_IPV6
  			  	+ m_v6_outstanding
  #endif
  				;
  		}
  
  	private:
  #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING || defined TORRENT_ERROR_LOGGING
  	// necessary for logging member offsets
  	public:
  #endif
  
  		// observers on this udp socket
  		std::vector<udp_socket_observer*> m_observers;
  		std::vector<udp_socket_observer*> m_added_observers;
  
  		// this is true while iterating over the observers
  		// vector, invoking observer hooks. We may not
  		// add new observers during this time, since it
  		// may invalidate the iterator. If this is true,
  		// instead add new observers to m_added_observers
  		// and they will be added later
  		bool m_observers_locked;
  
  		void call_handler(error_code const& ec, udp::endpoint const& ep, char const* buf, int size);
  		void call_handler(error_code const& ec, const char* host, char const* buf, int size);
  		void call_drained_handler();
  		void call_writable_handler();
  
  		void on_writable(error_code const& ec, udp::socket* s);
  
  		void setup_read(udp::socket* s);
  		void on_read(error_code const& ec, udp::socket* s);
  		void on_read_impl(udp::socket* sock, udp::endpoint const& ep
  			, error_code const& e, std::size_t bytes_transferred);
  		void on_name_lookup(error_code const& e, tcp::resolver::iterator i);
  		void on_timeout();
  		void on_connect(int ticket);
  		void on_connected(error_code const& ec);
  		void handshake1(error_code const& e);
  		void handshake2(error_code const& e);
  		void handshake3(error_code const& e);
  		void handshake4(error_code const& e);
  		void socks_forward_udp();
  		void connect1(error_code const& e);
  		void connect2(error_code const& e);
  		void hung_up(error_code const& e);
  
  		void drain_queue();
  
  		void wrap(udp::endpoint const& ep, char const* p, int len, error_code& ec);
  		void wrap(char const* hostname, int port, char const* p, int len, error_code& ec);
  		void unwrap(error_code const& e, char const* buf, int size);
  
  #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
  
  #if defined BOOST_HAS_PTHREADS
  		mutable pthread_t m_thread;
  #endif
  		bool is_single_thread() const
  		{
  #if defined BOOST_HAS_PTHREADS
  			if (m_thread == 0)
  				m_thread = pthread_self();
  			return m_thread == pthread_self();
  #endif
  			return true;
  		}
  #endif
  
  		udp::socket m_ipv4_sock;
  		int m_buf_size;
  
  		// if the buffer size is attempted
  		// to be changed while the buffer is
  		// being used, this member is set to
  		// the desired size, and it's resized
  		// later
  		int m_new_buf_size;
  		char* m_buf;
  
  #if TORRENT_USE_IPV6
  		udp::socket m_ipv6_sock;
  #endif
  
  		boost::uint16_t m_bind_port;
  		boost::uint8_t m_v4_outstanding;
  #if TORRENT_USE_IPV6
  		boost::uint8_t m_v6_outstanding;
  #endif
  
  		tcp::socket m_socks5_sock;
  		int m_connection_ticket;
  		proxy_settings m_proxy_settings;
  		connection_queue& m_cc;
  		tcp::resolver m_resolver;
  		char m_tmp_buf[270];
  		bool m_queue_packets;
  		bool m_tunnel_packets;
  		bool m_force_proxy;
  		bool m_abort;
  
  		// this is the endpoint the proxy server lives at.
  		// when performing a UDP associate, we get another
  		// endpoint (presumably on the same IP) where we're
  		// supposed to send UDP packets.
  		udp::endpoint m_proxy_addr;
  
  		// this is where UDP packets that are to be forwarded
  		// are sent. The result from UDP ASSOCIATE is stored
  		// in here.
  		udp::endpoint m_udp_proxy_addr;
  
  		// while we're connecting to the proxy
  		// we have to queue the packets, we'll flush
  		// them once we're connected
  		std::deque<queued_packet> m_queue;
  
  		// counts the number of outstanding async
  		// operations hanging on this socket
  		int m_outstanding_ops;
  
  #if TORRENT_USE_IPV6
  		bool m_v6_write_subscribed:1;
  #endif
  		bool m_v4_write_subscribed:1;
  
  #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS
  		bool m_started;
  		int m_magic;
  		int m_outstanding_when_aborted;
  		int m_outstanding_connect;
  		int m_outstanding_timeout;
  		int m_outstanding_resolve;
  		int m_outstanding_connect_queue;
  		int m_outstanding_socks;
  #endif
  	};
  
  	struct rate_limited_udp_socket : public udp_socket
  	{
  		rate_limited_udp_socket(io_service& ios, connection_queue& cc);
  		void set_rate_limit(int limit) { m_rate_limit = limit; }
  		bool send(udp::endpoint const& ep, char const* p, int len, error_code& ec, int flags = 0);
  
  	private:
  
  		int m_rate_limit;
  		int m_quota;
  		ptime m_last_tick;
  	};
  }
  
  #endif
  
  