441 lines
12 KiB
C++
441 lines
12 KiB
C++
/*
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Copyright (c) 2003 - 2006, Arvid Norberg
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Copyright (c) 2007, Arvid Norberg, Un Shyam
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the distribution.
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* Neither the name of the author nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TORRENT_BT_PEER_CONNECTION_HPP_INCLUDED
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#define TORRENT_BT_PEER_CONNECTION_HPP_INCLUDED
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#include <ctime>
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#include <algorithm>
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#include <vector>
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#include <string>
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#include "libtorrent/debug.hpp"
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#ifdef _MSC_VER
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#pragma warning(push, 1)
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#endif
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#include <boost/smart_ptr.hpp>
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#include <boost/noncopyable.hpp>
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#include <boost/array.hpp>
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#include <boost/optional.hpp>
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#include <boost/cstdint.hpp>
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#ifdef _MSC_VER
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#pragma warning(pop)
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#endif
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#include "libtorrent/buffer.hpp"
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#include "libtorrent/peer_connection.hpp"
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#include "libtorrent/socket.hpp"
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#include "libtorrent/peer_id.hpp"
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#include "libtorrent/stat.hpp"
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#include "libtorrent/alert.hpp"
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#include "libtorrent/torrent.hpp"
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#include "libtorrent/peer_request.hpp"
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#include "libtorrent/piece_block_progress.hpp"
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#include "libtorrent/config.hpp"
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#include "libtorrent/pe_crypto.hpp"
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namespace libtorrent
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{
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class torrent;
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namespace detail
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{
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struct session_impl;
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}
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class TORRENT_EXPORT bt_peer_connection
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: public peer_connection
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{
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friend class invariant_access;
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public:
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// this is the constructor where the we are the active part.
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// The peer_conenction should handshake and verify that the
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// other end has the correct id
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bt_peer_connection(
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aux::session_impl& ses
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, boost::weak_ptr<torrent> t
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, boost::shared_ptr<socket_type> s
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, tcp::endpoint const& remote
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, policy::peer* peerinfo);
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// with this constructor we have been contacted and we still don't
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// know which torrent the connection belongs to
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bt_peer_connection(
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aux::session_impl& ses
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, boost::shared_ptr<socket_type> s
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, tcp::endpoint const& remote
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, policy::peer* peerinfo);
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void start();
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enum { upload_only_msg = 2, share_mode_msg = 3 };
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~bt_peer_connection();
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#ifndef TORRENT_DISABLE_ENCRYPTION
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bool supports_encryption() const
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{ return m_encrypted; }
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#endif
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virtual int type() const { return peer_connection::bittorrent_connection; }
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enum message_type
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{
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// standard messages
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msg_choke = 0,
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msg_unchoke,
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msg_interested,
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msg_not_interested,
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msg_have,
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msg_bitfield,
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msg_request,
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msg_piece,
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msg_cancel,
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// DHT extension
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msg_dht_port,
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// FAST extension
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msg_suggest_piece = 0xd,
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msg_have_all,
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msg_have_none,
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msg_reject_request,
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msg_allowed_fast,
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// extension protocol message
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msg_extended = 20,
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num_supported_messages
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};
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// called from the main loop when this connection has any
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// work to do.
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void on_sent(error_code const& error
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, std::size_t bytes_transferred);
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void on_receive(error_code const& error
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, std::size_t bytes_transferred);
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virtual void get_specific_peer_info(peer_info& p) const;
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virtual bool in_handshake() const;
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#ifndef TORRENT_DISABLE_EXTENSIONS
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bool support_extensions() const { return m_supports_extensions; }
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#endif
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// the message handlers are called
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// each time a recv() returns some new
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// data, the last time it will be called
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// is when the entire packet has been
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// received, then it will no longer
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// be called. i.e. most handlers need
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// to check how much of the packet they
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// have received before any processing
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void on_keepalive();
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void on_choke(int received);
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void on_unchoke(int received);
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void on_interested(int received);
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void on_not_interested(int received);
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void on_have(int received);
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void on_bitfield(int received);
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void on_request(int received);
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void on_piece(int received);
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void on_cancel(int received);
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// DHT extension
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void on_dht_port(int received);
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// FAST extension
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void on_suggest_piece(int received);
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void on_have_all(int received);
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void on_have_none(int received);
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void on_reject_request(int received);
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void on_allowed_fast(int received);
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void on_extended(int received);
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void on_extended_handshake();
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typedef void (bt_peer_connection::*message_handler)(int received);
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// the following functions appends messages
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// to the send buffer
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void write_choke();
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void write_unchoke();
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void write_interested();
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void write_not_interested();
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void write_request(peer_request const& r);
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void write_cancel(peer_request const& r);
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void write_bitfield();
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void write_have(int index);
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void write_piece(peer_request const& r, disk_buffer_holder& buffer);
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void write_handshake();
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#ifndef TORRENT_DISABLE_EXTENSIONS
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void write_extensions();
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void write_upload_only();
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void write_share_mode();
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#endif
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void write_metadata(std::pair<int, int> req);
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void write_metadata_request(std::pair<int, int> req);
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void write_keepalive();
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// DHT extension
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void write_dht_port(int listen_port);
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// FAST extension
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void write_have_all();
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void write_have_none();
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void write_reject_request(peer_request const&);
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void write_allow_fast(int piece);
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void write_suggest(int piece);
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void on_connected();
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void on_metadata();
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#ifdef TORRENT_DEBUG
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void check_invariant() const;
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ptime m_last_choke;
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#endif
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private:
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bool dispatch_message(int received);
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// returns the block currently being
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// downloaded. And the progress of that
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// block. If the peer isn't downloading
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// a piece for the moment, the boost::optional
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// will be invalid.
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boost::optional<piece_block_progress> downloading_piece_progress() const;
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#ifndef TORRENT_DISABLE_ENCRYPTION
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// if (is_local()), we are 'a' otherwise 'b'
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//
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// 1. a -> b dhkey, pad
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// 2. b -> a dhkey, pad
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// 3. a -> b sync, payload
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// 4. b -> a sync, payload
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// 5. a -> b payload
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void write_pe1_2_dhkey();
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void write_pe3_sync();
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void write_pe4_sync(int crypto_select);
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void write_pe_vc_cryptofield(buffer::interval& write_buf
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, int crypto_field, int pad_size);
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// stream key (info hash of attached torrent)
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// secret is the DH shared secret
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// initializes m_RC4_handler
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void init_pe_RC4_handler(char const* secret, sha1_hash const& stream_key);
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public:
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// these functions encrypt the send buffer if m_rc4_encrypted
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// is true, otherwise it passes the call to the
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// peer_connection functions of the same names
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virtual void append_const_send_buffer(char const* buffer, int size);
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void send_buffer(char const* buf, int size, int flags = 0);
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buffer::interval allocate_send_buffer(int size);
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template <class Destructor>
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void append_send_buffer(char* buffer, int size, Destructor const& destructor)
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{
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#ifndef TORRENT_DISABLE_ENCRYPTION
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if (m_rc4_encrypted)
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{
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TORRENT_ASSERT(send_buffer_size() == m_encrypted_bytes);
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m_RC4_handler->encrypt(buffer, size);
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#ifdef TORRENT_DEBUG
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m_encrypted_bytes += size;
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TORRENT_ASSERT(m_encrypted_bytes == send_buffer_size() + size);
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#endif
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}
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#endif
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peer_connection::append_send_buffer(buffer, size, destructor);
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}
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void setup_send();
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private:
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void encrypt_pending_buffer();
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// Returns offset at which bytestream (src, src + src_size)
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// matches bytestream(target, target + target_size).
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// If no sync found, return -1
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int get_syncoffset(char const* src, int src_size
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, char const* target, int target_size) const;
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#endif
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enum state
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{
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#ifndef TORRENT_DISABLE_ENCRYPTION
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read_pe_dhkey = 0,
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read_pe_syncvc,
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read_pe_synchash,
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read_pe_skey_vc,
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read_pe_cryptofield,
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read_pe_pad,
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read_pe_ia,
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init_bt_handshake,
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read_protocol_identifier,
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#else
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read_protocol_identifier = 0,
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#endif
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read_info_hash,
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read_peer_id,
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// handshake complete
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read_packet_size,
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read_packet
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};
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#ifndef TORRENT_DISABLE_ENCRYPTION
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enum
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{
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handshake_len = 68,
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dh_key_len = 96
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};
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#endif
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std::string m_client_version;
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// state of on_receive
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state m_state;
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static const message_handler m_message_handler[num_supported_messages];
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// this is a queue of ranges that describes
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// where in the send buffer actual payload
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// data is located. This is currently
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// only used to be able to gather statistics
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// seperately on payload and protocol data.
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struct range
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{
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range(int s, int l)
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: start(s)
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, length(l)
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{
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TORRENT_ASSERT(s >= 0);
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TORRENT_ASSERT(l > 0);
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}
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int start;
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int length;
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};
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static bool range_below_zero(const range& r)
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{ return r.start < 0; }
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std::vector<range> m_payloads;
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// we have suggested these pieces to the peer
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// don't suggest it again
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bitfield m_sent_suggested_pieces;
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#ifndef TORRENT_DISABLE_EXTENSIONS
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// the message ID for upload only message
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// 0 if not supported
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int m_upload_only_id;
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// the message ID for share mode message
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// 0 if not supported
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int m_share_mode_id;
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char m_reserved_bits[8];
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// this is set to true if the handshake from
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// the peer indicated that it supports the
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// extension protocol
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bool m_supports_extensions:1;
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#endif
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bool m_supports_dht_port:1;
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bool m_supports_fast:1;
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#ifndef TORRENT_DISABLE_ENCRYPTION
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// this is set to true after the encryption method has been
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// succesfully negotiated (either plaintext or rc4), to signal
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// automatic encryption/decryption.
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bool m_encrypted;
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// true if rc4, false if plaintext
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bool m_rc4_encrypted;
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// used to disconnect peer if sync points are not found within
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// the maximum number of bytes
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int m_sync_bytes_read;
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// hold information about latest allocated send buffer
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// need to check for non zero (begin, end) for operations with this
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buffer::interval m_enc_send_buffer;
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// initialized during write_pe1_2_dhkey, and destroyed on
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// creation of m_RC4_handler. Cannot reinitialize once
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// initialized.
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boost::scoped_ptr<dh_key_exchange> m_dh_key_exchange;
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// if RC4 is negotiated, this is used for
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// encryption/decryption during the entire session. Destroyed
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// if plaintext is selected
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boost::scoped_ptr<RC4_handler> m_RC4_handler;
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// (outgoing only) synchronize verification constant with
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// remote peer, this will hold RC4_decrypt(vc). Destroyed
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// after the sync step.
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boost::scoped_array<char> m_sync_vc;
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// (incoming only) synchronize hash with remote peer, holds
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// the sync hash (hash("req1",secret)). Destroyed after the
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// sync step.
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boost::scoped_ptr<sha1_hash> m_sync_hash;
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#endif // #ifndef TORRENT_DISABLE_ENCRYPTION
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#ifdef TORRENT_DEBUG
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// this is set to true when the client's
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// bitfield is sent to this peer
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bool m_sent_bitfield;
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bool m_in_constructor;
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bool m_sent_handshake;
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// the number of bytes in the send buffer
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// that have been encrypted (only used for
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// encrypted connections)
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public:
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int m_encrypted_bytes;
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#endif
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};
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}
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#endif // TORRENT_BT_PEER_CONNECTION_HPP_INCLUDED
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