/* Copyright (c) 2003, 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. */ #include "libtorrent/pch.hpp" #ifdef _MSC_VER #pragma warning(push, 1) #endif #include #include #ifdef _MSC_VER #pragma warning(pop) #endif #include "libtorrent/peer_connection.hpp" #include "libtorrent/web_peer_connection.hpp" #include "libtorrent/policy.hpp" #include "libtorrent/torrent.hpp" #include "libtorrent/socket.hpp" #include "libtorrent/alert_types.hpp" #include "libtorrent/invariant_check.hpp" #include "libtorrent/time.hpp" #include "libtorrent/aux_/session_impl.hpp" #include "libtorrent/piece_picker.hpp" #include "libtorrent/broadcast_socket.hpp" #include "libtorrent/peer_info.hpp" #include "libtorrent/random.hpp" #include "libtorrent/extensions.hpp" #ifdef TORRENT_DEBUG #include "libtorrent/bt_peer_connection.hpp" #endif namespace { using namespace libtorrent; struct match_peer_endpoint { match_peer_endpoint(tcp::endpoint const& ep) : m_ep(ep) {} bool operator()(policy::peer const* p) const { TORRENT_ASSERT(p->in_use); return p->address() == m_ep.address() && p->port == m_ep.port(); } tcp::endpoint const& m_ep; }; #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS struct match_peer_connection { match_peer_connection(peer_connection const& c) : m_conn(c) {} bool operator()(policy::peer const* p) const { TORRENT_ASSERT(p->in_use); return p->connection == &m_conn; } peer_connection const& m_conn; }; struct match_peer_connection_or_endpoint { match_peer_connection_or_endpoint(peer_connection const& c) : m_conn(c) {} bool operator()(policy::peer const* p) const { TORRENT_ASSERT(p->in_use); return p->connection == &m_conn || (p->ip() == m_conn.remote() && p->connectable); } peer_connection const& m_conn; }; #endif } namespace libtorrent { // returns the rank of a peer's source. We have an affinity // to connecting to peers with higher rank. This is to avoid // problems when our peer list is diluted by stale peers from // the resume data for instance int source_rank(int source_bitmask) { int ret = 0; if (source_bitmask & peer_info::tracker) ret |= 1 << 5; if (source_bitmask & peer_info::lsd) ret |= 1 << 4; if (source_bitmask & peer_info::dht) ret |= 1 << 3; if (source_bitmask & peer_info::pex) ret |= 1 << 2; return ret; } // the case where ignore_peer is motivated is if two peers // have only one piece that we don't have, and it's the // same piece for both peers. Then they might get into an // infinite loop, fighting to request the same blocks. void request_a_block(torrent& t, peer_connection& c) { if (t.is_seed()) return; if (c.no_download()) return; if (t.upload_mode()) return; if (c.is_disconnecting()) return; // don't request pieces before we have the metadata if (!t.valid_metadata()) return; // don't request pieces before the peer is properly // initialized after we have the metadata if (!t.are_files_checked()) return; TORRENT_ASSERT(t.valid_metadata()); TORRENT_ASSERT(c.peer_info_struct() != 0 || c.type() != peer_connection::bittorrent_connection); int num_requests = c.desired_queue_size() - (int)c.download_queue().size() - (int)c.request_queue().size(); #ifdef TORRENT_VERBOSE_LOGGING c.peer_log("*** PIECE_PICKER [ req: %d engame: %d ]", num_requests, c.endgame()); #endif TORRENT_ASSERT(c.desired_queue_size() > 0); // if our request queue is already full, we // don't have to make any new requests yet if (num_requests <= 0) return; piece_picker& p = t.picker(); std::vector interesting_pieces; interesting_pieces.reserve(100); int prefer_whole_pieces = c.prefer_whole_pieces(); if (prefer_whole_pieces == 0) { prefer_whole_pieces = c.statistics().download_payload_rate() * t.settings().whole_pieces_threshold > t.torrent_file().piece_length() ? 1 : 0; } // if we prefer whole pieces, the piece picker will pick at least // the number of blocks we want, but it will try to make the picked // blocks be from whole pieces, possibly by returning more blocks // than we requested. #ifdef TORRENT_DEBUG error_code ec; TORRENT_ASSERT(c.remote() == c.get_socket()->remote_endpoint(ec) || ec); #endif aux::session_impl& ses = t.session(); std::vector const& dq = c.download_queue(); std::vector const& rq = c.request_queue(); std::vector const& suggested = c.suggested_pieces(); bitfield const* bits = &c.get_bitfield(); bitfield fast_mask; if (c.has_peer_choked()) { // if we are choked we can only pick pieces from the // allowed fast set. The allowed fast set is sorted // in ascending priority order std::vector const& allowed_fast = c.allowed_fast(); // build a bitmask with only the allowed pieces in it fast_mask.resize(c.get_bitfield().size(), false); for (std::vector::const_iterator i = allowed_fast.begin() , end(allowed_fast.end()); i != end; ++i) if ((*bits)[*i]) fast_mask.set_bit(*i); bits = &fast_mask; } piece_picker::piece_state_t state; peer_connection::peer_speed_t speed = c.peer_speed(); if (speed == peer_connection::fast) state = piece_picker::fast; else if (speed == peer_connection::medium) state = piece_picker::medium; else state = piece_picker::slow; // picks the interesting pieces from this peer // the integer is the number of pieces that // should be guaranteed to be available for download // (if num_requests is too big, too many pieces are // picked and cpu-time is wasted) // the last argument is if we should prefer whole pieces // for this peer. If we're downloading one piece in 20 seconds // then use this mode. p.pick_pieces(*bits, interesting_pieces , num_requests, prefer_whole_pieces, c.peer_info_struct() , state, c.picker_options(), suggested, t.num_peers()); #ifdef TORRENT_VERBOSE_LOGGING c.peer_log("*** PIECE_PICKER [ prefer_whole: %d picked: %d ]" , prefer_whole_pieces, int(interesting_pieces.size())); #endif // if the number of pieces we have + the number of pieces // we're requesting from is less than the number of pieces // in the torrent, there are still some unrequested pieces // and we're not strictly speaking in end-game mode yet // also, if we already have at least one outstanding // request, we shouldn't pick any busy pieces either bool dont_pick_busy_blocks = (ses.m_settings.strict_end_game_mode && p.num_have() + int(p.get_download_queue().size()) < t.torrent_file().num_pieces()) || dq.size() + rq.size() > 0; // this is filled with an interesting piece // that some other peer is currently downloading piece_block busy_block = piece_block::invalid; for (std::vector::iterator i = interesting_pieces.begin(); i != interesting_pieces.end(); ++i) { #ifdef TORRENT_STATS ++ses.m_piece_picker_blocks; #endif if (prefer_whole_pieces == 0 && num_requests <= 0) break; int num_block_requests = p.num_peers(*i); if (num_block_requests > 0) { // have we picked enough pieces? if (num_requests <= 0) break; // this block is busy. This means all the following blocks // in the interesting_pieces list are busy as well, we might // as well just exit the loop if (dont_pick_busy_blocks) break; TORRENT_ASSERT(p.num_peers(*i) > 0); busy_block = *i; continue; } TORRENT_ASSERT(p.num_peers(*i) == 0); // don't request pieces we already have in our request queue // This happens when pieces time out or the peer sends us // pieces we didn't request. Those aren't marked in the // piece picker, but we still keep track of them in the // download queue if (std::find_if(dq.begin(), dq.end(), has_block(*i)) != dq.end() || std::find_if(rq.begin(), rq.end(), has_block(*i)) != rq.end()) { #ifdef TORRENT_DEBUG std::vector::const_iterator j = std::find_if(dq.begin(), dq.end(), has_block(*i)); if (j != dq.end()) TORRENT_ASSERT(j->timed_out || j->not_wanted); #endif continue; } // ok, we found a piece that's not being downloaded // by somebody else. request it from this peer // and return if (!c.add_request(*i, 0)) continue; TORRENT_ASSERT(p.num_peers(*i) == 1); TORRENT_ASSERT(p.is_requested(*i)); num_requests--; } // we have picked as many blocks as we should // we're done! if (num_requests <= 0) { // since we could pick as many blocks as we // requested without having to resort to picking // busy ones, we're not in end-game mode c.set_endgame(false); return; } // we did not pick as many pieces as we wanted, because // there aren't enough. This means we're in end-game mode // as long as we have at least one request outstanding, // we shouldn't pick another piece // if we are attempting to download 'allowed' pieces // and can't find any, that doesn't count as end-game if (!c.has_peer_choked()) c.set_endgame(true); // if we don't have any potential busy blocks to request // or if we already have outstanding requests, don't // pick a busy piece if (busy_block == piece_block::invalid || dq.size() + rq.size() > 0) { return; } #ifdef TORRENT_STATS ++ses.m_end_game_piece_picker_blocks; #endif #ifdef TORRENT_DEBUG piece_picker::downloading_piece st; p.piece_info(busy_block.piece_index, st); TORRENT_ASSERT(st.requested + st.finished + st.writing == p.blocks_in_piece(busy_block.piece_index)); #endif TORRENT_ASSERT(p.is_requested(busy_block)); TORRENT_ASSERT(!p.is_downloaded(busy_block)); TORRENT_ASSERT(!p.is_finished(busy_block)); TORRENT_ASSERT(p.num_peers(busy_block) > 0); c.add_request(busy_block, peer_connection::req_busy); } policy::policy(torrent* t) : m_torrent(t) , m_round_robin(0) , m_num_connect_candidates(0) , m_num_seeds(0) , m_finished(false) { TORRENT_ASSERT(t); } // disconnects and removes all peers that are now filtered void policy::ip_filter_updated() { INVARIANT_CHECK; aux::session_impl& ses = m_torrent->session(); if (!m_torrent->apply_ip_filter()) return; for (iterator i = m_peers.begin(); i != m_peers.end();) { if ((ses.m_ip_filter.access((*i)->address()) & ip_filter::blocked) == 0) { ++i; continue; } if (ses.m_alerts.should_post()) ses.m_alerts.post_alert(peer_blocked_alert(m_torrent->get_handle(), (*i)->address())); int current = i - m_peers.begin(); TORRENT_ASSERT(current >= 0); TORRENT_ASSERT(m_peers.size() > 0); TORRENT_ASSERT(i != m_peers.end()); if ((*i)->connection) { // disconnecting the peer here may also delete the // peer_info_struct. If that is the case, just continue int count = m_peers.size(); peer_connection* p = (*i)->connection; p->disconnect(errors::banned_by_ip_filter); // what *i refers to has changed, i.e. cur was deleted if (m_peers.size() < count) { i = m_peers.begin() + current; continue; } TORRENT_ASSERT((*i)->connection == 0 || (*i)->connection->peer_info_struct() == 0); } erase_peer(i); i = m_peers.begin() + current; } } void policy::erase_peer(policy::peer* p) { INVARIANT_CHECK; TORRENT_ASSERT(p->in_use); std::pair range = find_peers(p->address()); iterator iter = std::find_if(range.first, range.second, match_peer_endpoint(p->ip())); if (iter == range.second) return; erase_peer(iter); } // any peer that is erased from m_peers will be // erased through this function. This way we can make // sure that any references to the peer are removed // as well, such as in the piece picker. void policy::erase_peer(iterator i) { INVARIANT_CHECK; TORRENT_ASSERT(i != m_peers.end()); if (m_torrent->has_picker()) m_torrent->picker().clear_peer(*i); if ((*i)->seed) --m_num_seeds; if (is_connect_candidate(**i, m_finished)) { TORRENT_ASSERT(m_num_connect_candidates > 0); --m_num_connect_candidates; } TORRENT_ASSERT(m_num_connect_candidates < int(m_peers.size())); if (m_round_robin > i - m_peers.begin()) --m_round_robin; if (m_round_robin >= int(m_peers.size())) m_round_robin = 0; #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS TORRENT_ASSERT((*i)->in_use); (*i)->in_use = false; #endif #if TORRENT_USE_IPV6 if ((*i)->is_v6_addr) { TORRENT_ASSERT(m_torrent->session().m_ipv6_peer_pool.is_from( static_cast(*i))); m_torrent->session().m_ipv6_peer_pool.destroy( static_cast(*i)); } else #endif #if TORRENT_USE_I2P if ((*i)->is_i2p_addr) { TORRENT_ASSERT(m_torrent->session().m_i2p_peer_pool.is_from( static_cast(*i))); m_torrent->session().m_i2p_peer_pool.destroy( static_cast(*i)); } else #endif { TORRENT_ASSERT(m_torrent->session().m_ipv4_peer_pool.is_from( static_cast(*i))); m_torrent->session().m_ipv4_peer_pool.destroy( static_cast(*i)); } m_peers.erase(i); } bool policy::should_erase_immediately(peer const& p) const { TORRENT_ASSERT(p.in_use); return p.source == peer_info::resume_data; } bool policy::is_erase_candidate(peer const& pe, bool finished) const { TORRENT_ASSERT(pe.in_use); if (pe.connection) return false; if (is_connect_candidate(pe, finished)) return false; return (pe.failcount > 0) || (pe.source == peer_info::resume_data); } bool policy::is_force_erase_candidate(peer const& pe) const { TORRENT_ASSERT(pe.in_use); return pe.connection == 0; } void policy::erase_peers(int flags) { INVARIANT_CHECK; int max_peerlist_size = m_torrent->is_paused() ? m_torrent->settings().max_paused_peerlist_size : m_torrent->settings().max_peerlist_size; if (max_peerlist_size == 0 || m_peers.empty()) return; int erase_candidate = -1; int force_erase_candidate = -1; TORRENT_ASSERT(m_finished == m_torrent->is_finished()); int round_robin = random() % m_peers.size(); int low_watermark = max_peerlist_size * 95 / 100; if (low_watermark == max_peerlist_size) --low_watermark; for (int iterations = (std::min)(int(m_peers.size()), 300); iterations > 0; --iterations) { if (int(m_peers.size()) < low_watermark) break; if (round_robin == int(m_peers.size())) round_robin = 0; peer& pe = *m_peers[round_robin]; TORRENT_ASSERT(pe.in_use); int current = round_robin; if (is_erase_candidate(pe, m_finished) && (erase_candidate == -1 || !compare_peer_erase(*m_peers[erase_candidate], pe))) { if (should_erase_immediately(pe)) { if (erase_candidate > current) --erase_candidate; if (force_erase_candidate > current) --force_erase_candidate; TORRENT_ASSERT(current >= 0 && current < int(m_peers.size())); erase_peer(m_peers.begin() + current); continue; } else { erase_candidate = current; } } if (is_force_erase_candidate(pe) && (force_erase_candidate == -1 || !compare_peer_erase(*m_peers[force_erase_candidate], pe))) { force_erase_candidate = current; } ++round_robin; } if (erase_candidate > -1) { TORRENT_ASSERT(erase_candidate >= 0 && erase_candidate < int(m_peers.size())); erase_peer(m_peers.begin() + erase_candidate); } else if ((flags & force_erase) && force_erase_candidate > -1) { TORRENT_ASSERT(force_erase_candidate >= 0 && force_erase_candidate < int(m_peers.size())); erase_peer(m_peers.begin() + force_erase_candidate); } } void policy::ban_peer(policy::peer* p) { INVARIANT_CHECK; TORRENT_ASSERT(p->in_use); if (is_connect_candidate(*p, m_finished)) --m_num_connect_candidates; #ifdef TORRENT_STATS aux::session_impl& ses = m_torrent->session(); ++ses.m_num_banned_peers; #endif p->banned = true; TORRENT_ASSERT(!is_connect_candidate(*p, m_finished)); } void policy::set_connection(policy::peer* p, peer_connection* c) { INVARIANT_CHECK; TORRENT_ASSERT(p->in_use); TORRENT_ASSERT(c); const bool was_conn_cand = is_connect_candidate(*p, m_finished); p->connection = c; if (was_conn_cand) --m_num_connect_candidates; } void policy::set_failcount(policy::peer* p, int f) { INVARIANT_CHECK; TORRENT_ASSERT(p->in_use); const bool was_conn_cand = is_connect_candidate(*p, m_finished); p->failcount = f; if (was_conn_cand != is_connect_candidate(*p, m_finished)) { if (was_conn_cand) --m_num_connect_candidates; else ++m_num_connect_candidates; } } bool policy::is_connect_candidate(peer const& p, bool finished) const { TORRENT_ASSERT(p.in_use); if (p.connection || p.banned || p.web_seed || !p.connectable || (p.seed && finished) || int(p.failcount) >= m_torrent->settings().max_failcount) return false; aux::session_impl const& ses = m_torrent->session(); if (ses.m_port_filter.access(p.port) & port_filter::blocked) return false; // only apply this to peers we've only heard // about from the DHT if (ses.m_settings.no_connect_privileged_ports && p.port < 1024 && p.source == peer_info::dht) return false; return true; } policy::iterator policy::find_connect_candidate(int session_time) { INVARIANT_CHECK; int candidate = -1; int erase_candidate = -1; TORRENT_ASSERT(m_finished == m_torrent->is_finished()); int min_reconnect_time = m_torrent->settings().min_reconnect_time; address external_ip = m_torrent->session().external_address(); // don't bias any particular peers when seeding if (m_finished || external_ip == address()) { // set external_ip to a random value, to // radomize which peers we prefer address_v4::bytes_type bytes; std::generate(bytes.begin(), bytes.end(), &random); external_ip = address_v4(bytes); } if (m_round_robin >= int(m_peers.size())) m_round_robin = 0; #ifndef TORRENT_DISABLE_DHT bool pinged = false; #endif int max_peerlist_size = m_torrent->is_paused() ?m_torrent->settings().max_paused_peerlist_size :m_torrent->settings().max_peerlist_size; for (int iterations = (std::min)(int(m_peers.size()), 300); iterations > 0; --iterations) { if (m_round_robin >= int(m_peers.size())) m_round_robin = 0; peer& pe = *m_peers[m_round_robin]; TORRENT_ASSERT(pe.in_use); int current = m_round_robin; #ifndef TORRENT_DISABLE_DHT // try to send a DHT ping to this peer // as well, to figure out if it supports // DHT (uTorrent and BitComet doesn't // advertise support) if (!pinged && !pe.added_to_dht) { udp::endpoint node(pe.address(), pe.port); m_torrent->session().add_dht_node(node); pe.added_to_dht = true; pinged = true; } #endif // if the number of peers is growing large // we need to start weeding. if (int(m_peers.size()) >= max_peerlist_size * 0.95 && max_peerlist_size > 0) { if (is_erase_candidate(pe, m_finished) && (erase_candidate == -1 || !compare_peer_erase(*m_peers[erase_candidate], pe))) { if (should_erase_immediately(pe)) { if (erase_candidate > current) --erase_candidate; if (candidate > current) --candidate; erase_peer(m_peers.begin() + current); continue; } else { erase_candidate = current; } } } ++m_round_robin; if (!is_connect_candidate(pe, m_finished)) continue; // compare peer returns true if lhs is better than rhs. In this // case, it returns true if the current candidate is better than // pe, which is the peer m_round_robin points to. If it is, just // keep looking. if (candidate != -1 && compare_peer(*m_peers[candidate], pe, external_ip)) continue; if (pe.last_connected && session_time - pe.last_connected < (int(pe.failcount) + 1) * min_reconnect_time) continue; candidate = current; } if (erase_candidate > -1) { if (candidate > erase_candidate) --candidate; erase_peer(m_peers.begin() + erase_candidate); } #if defined TORRENT_LOGGING || defined TORRENT_VERBOSE_LOGGING if (candidate != -1) { (*m_torrent->session().m_logger) << time_now_string() << " *** FOUND CONNECTION CANDIDATE [" " ip: " << m_peers[candidate]->ip() << " d: " << cidr_distance(external_ip, m_peers[candidate]->address()) << " external: " << external_ip << " t: " << (session_time - m_peers[candidate]->last_connected) << " ]\n"; } #endif if (candidate == -1) return m_peers.end(); return m_peers.begin() + candidate; } bool policy::new_connection(peer_connection& c, int session_time) { TORRENT_ASSERT(!c.is_outgoing()); INVARIANT_CHECK; // if the connection comes from the tracker, // it's probably just a NAT-check. Ignore the // num connections constraint then. // TODO: only allow _one_ connection to use this // override at a time error_code ec; TORRENT_ASSERT(c.remote() == c.get_socket()->remote_endpoint(ec) || ec); TORRENT_ASSERT(!m_torrent->is_paused()); aux::session_impl& ses = m_torrent->session(); if (m_torrent->num_peers() >= m_torrent->max_connections() && ses.num_connections() >= ses.settings().connections_limit && c.remote().address() != m_torrent->current_tracker().address()) { #if defined TORRENT_LOGGING || defined TORRENT_VERBOSE_LOGGING (*m_torrent->session().m_logger) << time_now_string() << " *** TOO MANY CONNECTIONS [" " torrent: " << m_torrent->name() << " torrent peers: " << m_torrent->num_peers() << " torrent limit: " << m_torrent->max_connections() << " global peers: " << ses.num_connections() << " global limit: " << ses.settings().connections_limit << " global list peers " << int(m_peers.size()) << " global list limit: " << m_torrent->settings().max_peerlist_size << " ]\n"; #endif c.disconnect(errors::too_many_connections); return false; } #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING if (c.remote().address() == m_torrent->current_tracker().address()) { m_torrent->debug_log("overriding connection limit for tracker NAT-check"); } #endif iterator iter; peer* i = 0; bool found = false; if (m_torrent->settings().allow_multiple_connections_per_ip) { tcp::endpoint remote = c.remote(); std::pair range = find_peers(remote.address()); iter = std::find_if(range.first, range.second, match_peer_endpoint(remote)); if (iter != range.second) found = true; } else { iter = std::lower_bound( m_peers.begin(), m_peers.end() , c.remote().address(), peer_address_compare() ); if (iter != m_peers.end() && (*iter)->address() == c.remote().address()) found = true; } // make sure the iterator we got is properly sorted relative // to the connection's address // TORRENT_ASSERT(m_peers.empty() // || (iter == m_peers.end() && (*(iter-1))->address() < c.remote().address()) // || (iter != m_peers.end() && c.remote().address() < (*iter)->address()) // || (iter != m_peers.end() && iter != m_peers.begin() && (*(iter-1))->address() < c.remote().address())); if (found) { i = *iter; TORRENT_ASSERT(i->connection != &c); TORRENT_ASSERT(i->in_use); if (i->banned) { c.disconnect(errors::peer_banned); return false; } if (i->connection != 0) { boost::shared_ptr other_socket = i->connection->get_socket(); boost::shared_ptr this_socket = c.get_socket(); error_code ec1; error_code ec2; bool self_connection = other_socket->remote_endpoint(ec2) == this_socket->local_endpoint(ec1) || other_socket->local_endpoint(ec2) == this_socket->remote_endpoint(ec1); if (ec1) { c.disconnect(ec1); return false; } if (self_connection) { c.disconnect(errors::self_connection, 1); i->connection->disconnect(errors::self_connection, 1); TORRENT_ASSERT(i->connection == 0); return false; } TORRENT_ASSERT(i->connection != &c); // the new connection is a local (outgoing) connection // or the current one is already connected if (ec2) { i->connection->disconnect(ec2); TORRENT_ASSERT(i->connection == 0); } else if (!i->connection->is_connecting() || c.is_outgoing()) { c.disconnect(errors::duplicate_peer_id); return false; } else { #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING m_torrent->debug_log("duplicate connection. existing connection" " is connecting and this connection is incoming. closing existing " "connection in favour of this one"); #endif i->connection->disconnect(errors::duplicate_peer_id); TORRENT_ASSERT(i->connection == 0); } } if (is_connect_candidate(*i, m_finished)) { m_num_connect_candidates--; TORRENT_ASSERT(m_num_connect_candidates >= 0); if (m_num_connect_candidates < 0) m_num_connect_candidates = 0; } } else { // we don't have any info about this peer. // add a new entry error_code ec; TORRENT_ASSERT(c.remote() == c.get_socket()->remote_endpoint(ec) || ec); if (int(m_peers.size()) >= m_torrent->settings().max_peerlist_size) { // this may invalidate our iterator! erase_peers(force_erase); if (int(m_peers.size()) >= m_torrent->settings().max_peerlist_size) { #if defined TORRENT_LOGGING || defined TORRENT_VERBOSE_LOGGING (*m_torrent->session().m_logger) << time_now_string() << " *** TOO MANY CONNECTIONS [" " torrent: " << m_torrent->name() << " torrent peers: " << m_torrent->num_peers() << " torrent limit: " << m_torrent->max_connections() << " global peers: " << ses.num_connections() << " global limit: " << ses.settings().connections_limit << " global list peers " << int(m_peers.size()) << " global list limit: " << m_torrent->settings().max_peerlist_size << " ]\n"; #endif c.disconnect(errors::too_many_connections); return false; } // restore it iter = std::lower_bound( m_peers.begin(), m_peers.end() , c.remote().address(), peer_address_compare() ); } #if TORRENT_USE_IPV6 bool is_v6 = c.remote().address().is_v6(); #endif peer* p = #if TORRENT_USE_IPV6 is_v6 ? (peer*)m_torrent->session().m_ipv6_peer_pool.malloc() : #endif (peer*)m_torrent->session().m_ipv4_peer_pool.malloc(); if (p == 0) return false; #if TORRENT_USE_IPV6 if (is_v6) m_torrent->session().m_ipv6_peer_pool.set_next_size(500); else #endif m_torrent->session().m_ipv4_peer_pool.set_next_size(500); #if TORRENT_USE_IPV6 if (is_v6) new (p) ipv6_peer(c.remote(), false, 0); else #endif new (p) ipv4_peer(c.remote(), false, 0); #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS p->in_use = true; #endif iter = m_peers.insert(iter, p); if (m_round_robin >= iter - m_peers.begin()) ++m_round_robin; i = *iter; #ifndef TORRENT_DISABLE_GEO_IP int as = ses.as_for_ip(c.remote().address()); #ifdef TORRENT_DEBUG i->inet_as_num = as; #endif i->inet_as = ses.lookup_as(as); #endif i->source = peer_info::incoming; } TORRENT_ASSERT(i); c.set_peer_info(i); TORRENT_ASSERT(i->connection == 0); c.add_stat(size_type(i->prev_amount_download) << 10, size_type(i->prev_amount_upload) << 10); // restore transfer rate limits int rate_limit; rate_limit = i->upload_rate_limit; if (rate_limit) c.set_upload_limit(rate_limit); rate_limit = i->download_rate_limit; if (rate_limit) c.set_download_limit(rate_limit); i->prev_amount_download = 0; i->prev_amount_upload = 0; i->connection = &c; TORRENT_ASSERT(i->connection); if (!c.fast_reconnect()) i->last_connected = session_time; // this cannot be a connect candidate anymore, since i->connection is set TORRENT_ASSERT(!is_connect_candidate(*i, m_finished)); TORRENT_ASSERT(has_connection(&c)); m_torrent->state_updated(); return true; } bool policy::update_peer_port(int port, policy::peer* p, int src) { TORRENT_ASSERT(p != 0); TORRENT_ASSERT(p->connection); TORRENT_ASSERT(p->in_use); INVARIANT_CHECK; if (p->port == port) return true; if (m_torrent->settings().allow_multiple_connections_per_ip) { tcp::endpoint remote(p->address(), port); std::pair range = find_peers(remote.address()); iterator i = std::find_if(range.first, range.second , match_peer_endpoint(remote)); if (i != range.second) { policy::peer& pp = **i; TORRENT_ASSERT(pp.in_use); if (pp.connection) { bool was_conn_cand = is_connect_candidate(pp, m_finished); // if we already have an entry with this // new endpoint, disconnect this one pp.connectable = true; pp.source |= src; if (!was_conn_cand && is_connect_candidate(pp, m_finished)) ++m_num_connect_candidates; p->connection->disconnect(errors::duplicate_peer_id); erase_peer(p); return false; } erase_peer(i); } } #ifdef TORRENT_DEBUG else { std::pair range = find_peers(p->address()); TORRENT_ASSERT(range.second - range.first == 1); } #endif bool was_conn_cand = is_connect_candidate(*p, m_finished); p->port = port; p->source |= src; p->connectable = true; if (was_conn_cand != is_connect_candidate(*p, m_finished)) { m_num_connect_candidates += was_conn_cand ? -1 : 1; TORRENT_ASSERT(m_num_connect_candidates >= 0); if (m_num_connect_candidates < 0) m_num_connect_candidates = 0; } return true; } // it's important that we don't dereference // p here, since it is allowed to be a dangling // pointer. see smart_ban.cpp bool policy::has_peer(policy::peer const* p) const { TORRENT_ASSERT(p->in_use); // find p in m_peers for (const_iterator i = m_peers.begin() , end(m_peers.end()); i != end; ++i) { if (*i == p) return true; } return false; } void policy::set_seed(policy::peer* p, bool s) { if (p == 0) return; TORRENT_ASSERT(p->in_use); if (p->seed == s) return; bool was_conn_cand = is_connect_candidate(*p, m_finished); p->seed = s; if (was_conn_cand && !is_connect_candidate(*p, m_finished)) { --m_num_connect_candidates; TORRENT_ASSERT(m_num_connect_candidates >= 0); if (m_num_connect_candidates < 0) m_num_connect_candidates = 0; } if (p->web_seed) return; if (s) ++m_num_seeds; else --m_num_seeds; TORRENT_ASSERT(m_num_seeds >= 0); TORRENT_ASSERT(m_num_seeds <= int(m_peers.size())); } bool policy::insert_peer(policy::peer* p, iterator iter, int flags) { TORRENT_ASSERT(p); TORRENT_ASSERT(p->in_use); int max_peerlist_size = m_torrent->is_paused() ?m_torrent->settings().max_paused_peerlist_size :m_torrent->settings().max_peerlist_size; if (max_peerlist_size && int(m_peers.size()) >= max_peerlist_size) { if (p->source == peer_info::resume_data) return false; erase_peers(); if (int(m_peers.size()) >= max_peerlist_size) return 0; // since some peers were removed, we need to // update the iterator to make it valid again #if TORRENT_USE_I2P if (p->is_i2p_addr) { iter = std::lower_bound( m_peers.begin(), m_peers.end() , p->dest(), peer_address_compare()); } else #endif iter = std::lower_bound( m_peers.begin(), m_peers.end() , p->address(), peer_address_compare()); } iter = m_peers.insert(iter, p); if (m_round_robin >= iter - m_peers.begin()) ++m_round_robin; #ifndef TORRENT_DISABLE_ENCRYPTION if (flags & 0x01) p->pe_support = true; #endif if (flags & 0x02) { p->seed = true; ++m_num_seeds; } if (flags & 0x04) p->supports_utp = true; if (flags & 0x08) p->supports_holepunch = true; #ifndef TORRENT_DISABLE_GEO_IP int as = m_torrent->session().as_for_ip(p->address()); #ifdef TORRENT_DEBUG p->inet_as_num = as; #endif p->inet_as = m_torrent->session().lookup_as(as); #endif if (is_connect_candidate(*p, m_finished)) ++m_num_connect_candidates; m_torrent->state_updated(); return true; } void policy::update_peer(policy::peer* p, int src, int flags , tcp::endpoint const& remote, char const* destination) { bool was_conn_cand = is_connect_candidate(*p, m_finished); TORRENT_ASSERT(p->in_use); p->connectable = true; TORRENT_ASSERT(p->address() == remote.address()); p->port = remote.port(); p->source |= src; // if this peer has failed before, decrease the // counter to allow it another try, since somebody // else is appearantly able to connect to it // only trust this if it comes from the tracker if (p->failcount > 0 && src == peer_info::tracker) --p->failcount; // if we're connected to this peer // we already know if it's a seed or not // so we don't have to trust this source if ((flags & 0x02) && !p->connection) { if (!p->seed) ++m_num_seeds; p->seed = true; } if (flags & 0x04) p->supports_utp = true; if (flags & 0x08) p->supports_holepunch = true; #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_LOGGING if (p->connection) { // this means we're already connected // to this peer. don't connect to // it again. error_code ec; char hex_pid[41]; to_hex((char*)&p->connection->pid()[0], 20, hex_pid); char msg[200]; snprintf(msg, 200, "already connected to peer: %s %s" , print_endpoint(remote).c_str(), hex_pid); m_torrent->debug_log(msg); TORRENT_ASSERT(p->connection->associated_torrent().lock().get() == m_torrent); } #endif if (was_conn_cand != is_connect_candidate(*p, m_finished)) { m_num_connect_candidates += was_conn_cand ? -1 : 1; if (m_num_connect_candidates < 0) m_num_connect_candidates = 0; } } #if TORRENT_USE_I2P policy::peer* policy::add_i2p_peer(char const* destination, int src, char flags) { INVARIANT_CHECK; bool found = false; iterator iter = std::lower_bound( m_peers.begin(), m_peers.end() , destination, peer_address_compare() ); if (iter != m_peers.end() && strcmp((*iter)->dest(), destination) == 0) found = true; peer* p = 0; if (!found) { // we don't have any info about this peer. // add a new entry p = (peer*)m_torrent->session().m_i2p_peer_pool.malloc(); if (p == 0) return 0; m_torrent->session().m_i2p_peer_pool.set_next_size(500); new (p) i2p_peer(destination, true, src); #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS p->in_use = true; #endif if (!insert_peer(p, iter, flags)) { #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS p->in_use = false; #endif m_torrent->session().m_i2p_peer_pool.destroy((i2p_peer*)p); return 0; } } else { p = *iter; update_peer(p, src, flags, tcp::endpoint(), destination); } m_torrent->state_updated(); return p; } #endif // TORRENT_USE_I2P policy::peer* policy::add_peer(tcp::endpoint const& remote, peer_id const& pid , int src, char flags) { INVARIANT_CHECK; // just ignore the obviously invalid entries if (remote.address() == address() || remote.port() == 0) return 0; aux::session_impl& ses = m_torrent->session(); // if this is an i2p torrent, and we don't allow mixed mode // no regular peers should ever be added! if (!ses.m_settings.allow_i2p_mixed && m_torrent->torrent_file().is_i2p()) { if (ses.m_alerts.should_post()) ses.m_alerts.post_alert(peer_blocked_alert(m_torrent->get_handle(), remote.address())); return 0; } port_filter const& pf = ses.m_port_filter; if (pf.access(remote.port()) & port_filter::blocked) { if (ses.m_alerts.should_post()) ses.m_alerts.post_alert(peer_blocked_alert(m_torrent->get_handle(), remote.address())); #ifndef TORRENT_DISABLE_EXTENSIONS m_torrent->notify_extension_add_peer(remote, src, torrent_plugin::filtered); #endif return 0; } if (ses.m_settings.no_connect_privileged_ports && remote.port() < 1024) { if (ses.m_alerts.should_post()) ses.m_alerts.post_alert(peer_blocked_alert(m_torrent->get_handle(), remote.address())); #ifndef TORRENT_DISABLE_EXTENSIONS m_torrent->notify_extension_add_peer(remote, src, torrent_plugin::filtered); #endif return 0; } // if the IP is blocked, don't add it if (m_torrent->apply_ip_filter() && (ses.m_ip_filter.access(remote.address()) & ip_filter::blocked)) { if (ses.m_alerts.should_post()) ses.m_alerts.post_alert(peer_blocked_alert(m_torrent->get_handle(), remote.address())); #ifndef TORRENT_DISABLE_EXTENSIONS m_torrent->notify_extension_add_peer(remote, src, torrent_plugin::filtered); #endif return 0; } iterator iter; peer* p = 0; bool found = false; if (m_torrent->settings().allow_multiple_connections_per_ip) { std::pair range = find_peers(remote.address()); iter = std::find_if(range.first, range.second, match_peer_endpoint(remote)); if (iter != range.second) found = true; } else { iter = std::lower_bound( m_peers.begin(), m_peers.end() , remote.address(), peer_address_compare() ); if (iter != m_peers.end() && (*iter)->address() == remote.address()) found = true; } if (!found) { // we don't have any info about this peer. // add a new entry #if TORRENT_USE_IPV6 bool is_v6 = remote.address().is_v6(); #endif p = #if TORRENT_USE_IPV6 is_v6 ? (peer*)m_torrent->session().m_ipv6_peer_pool.malloc() : #endif (peer*)m_torrent->session().m_ipv4_peer_pool.malloc(); if (p == 0) return 0; #if TORRENT_USE_IPV6 if (is_v6) m_torrent->session().m_ipv6_peer_pool.set_next_size(500); else #endif m_torrent->session().m_ipv4_peer_pool.set_next_size(500); #if TORRENT_USE_IPV6 if (is_v6) new (p) ipv6_peer(remote, true, src); else #endif new (p) ipv4_peer(remote, true, src); #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS p->in_use = true; #endif if (!insert_peer(p, iter, flags)) { #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS p->in_use = false; #endif #if TORRENT_USE_IPV6 if (is_v6) m_torrent->session().m_ipv6_peer_pool.destroy((ipv6_peer*)p); else #endif m_torrent->session().m_ipv4_peer_pool.destroy((ipv4_peer*)p); return 0; } #ifndef TORRENT_DISABLE_EXTENSIONS m_torrent->notify_extension_add_peer(remote, src, torrent_plugin::first_time); #endif } else { p = *iter; TORRENT_ASSERT(p->in_use); update_peer(p, src, flags, remote, 0); #ifndef TORRENT_DISABLE_EXTENSIONS m_torrent->notify_extension_add_peer(remote, src, 0); #endif } return p; } bool policy::connect_one_peer(int session_time) { INVARIANT_CHECK; TORRENT_ASSERT(m_torrent->want_more_peers()); iterator i = find_connect_candidate(session_time); if (i == m_peers.end()) return false; peer& p = **i; TORRENT_ASSERT(p.in_use); TORRENT_ASSERT(!p.banned); TORRENT_ASSERT(!p.connection); TORRENT_ASSERT(p.connectable); TORRENT_ASSERT(m_finished == m_torrent->is_finished()); TORRENT_ASSERT(is_connect_candidate(p, m_finished)); if (!m_torrent->connect_to_peer(&p)) { // failcount is a 5 bit value const bool was_conn_cand = is_connect_candidate(p, m_finished); if (p.failcount < 31) ++p.failcount; if (was_conn_cand && !is_connect_candidate(p, m_finished)) --m_num_connect_candidates; return false; } TORRENT_ASSERT(p.connection); TORRENT_ASSERT(!is_connect_candidate(p, m_finished)); return true; } // this is called whenever a peer connection is closed void policy::connection_closed(const peer_connection& c, int session_time) { INVARIANT_CHECK; peer* p = c.peer_info_struct(); // if we couldn't find the connection in our list, just ignore it. if (p == 0) return; TORRENT_ASSERT(p->in_use); // web seeds are special, they're not connected via the peer list // so they're not kept in m_peers TORRENT_ASSERT(p->web_seed || std::find_if( m_peers.begin() , m_peers.end() , match_peer_connection(c)) != m_peers.end()); TORRENT_ASSERT(p->connection == &c); TORRENT_ASSERT(!is_connect_candidate(*p, m_finished)); // save transfer rate limits p->upload_rate_limit = c.upload_limit(); p->download_rate_limit = c.download_limit(); p->connection = 0; p->optimistically_unchoked = false; // if fast reconnect is true, we won't // update the timestamp, and it will remain // the time when we initiated the connection. if (!c.fast_reconnect()) p->last_connected = session_time; if (c.failed()) { // failcount is a 5 bit value if (p->failcount < 31) ++p->failcount; } if (is_connect_candidate(*p, m_finished)) ++m_num_connect_candidates; // if we're already a seed, it's not as important // to keep all the possibly stale peers // if we're not a seed, but we have too many peers // start weeding the ones we only know from resume // data first // at this point it may be tempting to erase peers // from the peer list, but keep in mind that we might // have gotten to this point through new_connection, just // disconnecting an old peer, relying on this policy::peer // to still exist when we get back there, to assign the new // peer connection pointer to it. The peer list must // be left intact. // if we allow multiple connections per IP, and this peer // was incoming and it never advertised its listen // port, we don't really know which peer it was. In order // to avoid adding one entry for every single connection // the peer makes to us, don't save this entry if (m_torrent->settings().allow_multiple_connections_per_ip && !p->connectable) { erase_peer(p); } } void policy::peer_is_interesting(peer_connection& c) { INVARIANT_CHECK; // no peer should be interesting if we're finished TORRENT_ASSERT(!m_torrent->is_finished()); if (c.in_handshake()) return; c.send_interested(); if (c.has_peer_choked() && c.allowed_fast().empty()) return; request_a_block(*m_torrent, c); c.send_block_requests(); } void policy::recalculate_connect_candidates() { INVARIANT_CHECK; const bool is_finished = m_torrent->is_finished(); if (is_finished == m_finished) return; m_num_connect_candidates = 0; m_finished = is_finished; for (const_iterator i = m_peers.begin(); i != m_peers.end(); ++i) { m_num_connect_candidates += is_connect_candidate(**i, m_finished); } } #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS bool policy::has_connection(const peer_connection* c) { INVARIANT_CHECK; TORRENT_ASSERT(c); error_code ec; if (c->remote() != c->get_socket()->remote_endpoint(ec) && !ec) { fprintf(stderr, "c->remote: %s\nc->get_socket()->remote_endpoint: %s\n" , print_endpoint(c->remote()).c_str() , print_endpoint(c->get_socket()->remote_endpoint(ec)).c_str()); TORRENT_ASSERT(false); } return std::find_if( m_peers.begin() , m_peers.end() , match_peer_connection_or_endpoint(*c)) != m_peers.end(); } #endif #ifdef TORRENT_DEBUG void policy::check_invariant() const { TORRENT_ASSERT(m_num_connect_candidates >= 0); TORRENT_ASSERT(m_num_connect_candidates <= int(m_peers.size())); if (m_torrent->is_aborted()) return; #ifdef TORRENT_EXPENSIVE_INVARIANT_CHECKS int connected_peers = 0; int total_connections = 0; int nonempty_connections = 0; int connect_candidates = 0; std::set unique_test; const_iterator prev = m_peers.end(); for (const_iterator i = m_peers.begin(); i != m_peers.end(); ++i) { if (prev != m_peers.end()) ++prev; if (i == m_peers.begin() + 1) prev = m_peers.begin(); if (prev != m_peers.end()) { if (m_torrent->settings().allow_multiple_connections_per_ip) TORRENT_ASSERT(!((*i)->address() < (*prev)->address())); else TORRENT_ASSERT((*prev)->address() < (*i)->address()); } peer const& p = **i; TORRENT_ASSERT(p.in_use); if (is_connect_candidate(p, m_finished)) ++connect_candidates; #ifndef TORRENT_DISABLE_GEO_IP TORRENT_ASSERT(p.inet_as == 0 || p.inet_as->first == p.inet_as_num); #endif if (!m_torrent->settings().allow_multiple_connections_per_ip) { std::pair range = find_peers(p.address()); TORRENT_ASSERT(range.second - range.first == 1); } else { TORRENT_ASSERT(unique_test.count(p.ip()) == 0); unique_test.insert(p.ip()); // TORRENT_ASSERT(p.connection == 0 || p.ip() == p.connection->remote()); } ++total_connections; if (!p.connection) { continue; } if (p.optimistically_unchoked) { TORRENT_ASSERT(p.connection); TORRENT_ASSERT(!p.connection->is_choked()); } TORRENT_ASSERT(p.connection->peer_info_struct() == 0 || p.connection->peer_info_struct() == &p); ++nonempty_connections; if (!p.connection->is_disconnecting()) ++connected_peers; } TORRENT_ASSERT(m_num_connect_candidates == connect_candidates); int num_torrent_peers = 0; for (torrent::const_peer_iterator i = m_torrent->begin(); i != m_torrent->end(); ++i) { if ((*i)->is_disconnecting()) continue; // ignore web_peer_connections since they are not managed // by the policy class if ((*i)->type() != peer_connection::bittorrent_connection) continue; ++num_torrent_peers; } if (m_torrent->has_picker()) { piece_picker& p = m_torrent->picker(); std::vector downloaders = p.get_download_queue(); std::set peer_set; std::vector peers; for (std::vector::iterator i = downloaders.begin() , end(downloaders.end()); i != end; ++i) { p.get_downloaders(peers, i->index); std::copy(peers.begin(), peers.end() , std::insert_iterator >(peer_set, peer_set.begin())); } for (std::set::iterator i = peer_set.begin() , end(peer_set.end()); i != end; ++i) { policy::peer* p = static_cast(*i); if (p == 0) continue; TORRENT_ASSERT(p->in_use); if (p->connection == 0) continue; // web seeds are special, they're not connected via the peer list // so they're not kept in m_peers if (p->connection->type() != peer_connection::bittorrent_connection) continue; TORRENT_ASSERT(std::find_if(m_peers.begin(), m_peers.end() , match_peer_connection_or_endpoint(*p->connection)) != m_peers.end()); } } #endif // TORRENT_EXPENSIVE_INVARIANT_CHECKS // this invariant is a bit complicated. // the usual case should be that connected_peers // == num_torrent_peers. But when there's an incoming // connection, it will first be added to the policy // and then be added to the torrent. // When there's an outgoing connection, it will first // be added to the torrent and then to the policy. // that's why the two second cases are in there. /* TORRENT_ASSERT(connected_peers == num_torrent_peers || (connected_peers == num_torrent_peers + 1 && connected_peers > 0) || (connected_peers + 1 == num_torrent_peers && num_torrent_peers > 0)); */ } #endif // TORRENT_DEBUG policy::peer::peer(boost::uint16_t port, bool conn, int src) : prev_amount_upload(0) , prev_amount_download(0) , connection(0) #ifndef TORRENT_DISABLE_GEO_IP , inet_as(0) #endif , last_optimistically_unchoked(0) , last_connected(0) , port(port) , upload_rate_limit(0) , download_rate_limit(0) , hashfails(0) , failcount(0) , connectable(conn) , optimistically_unchoked(false) , seed(false) , fast_reconnects(0) , trust_points(0) , source(src) #ifndef TORRENT_DISABLE_ENCRYPTION , pe_support(true) #endif #if TORRENT_USE_IPV6 , is_v6_addr(false) #endif #if TORRENT_USE_I2P , is_i2p_addr(false) #endif , on_parole(false) , banned(false) #ifndef TORRENT_DISABLE_DHT , added_to_dht(false) #endif , supports_utp(true) // assume peers support utp , confirmed_supports_utp(false) , supports_holepunch(false) , web_seed(false) #if defined TORRENT_DEBUG || TORRENT_RELEASE_ASSERTS , in_use(false) #endif { TORRENT_ASSERT((src & 0xff) == src); } size_type policy::peer::total_download() const { if (connection != 0) { TORRENT_ASSERT(prev_amount_download == 0); return connection->statistics().total_payload_download(); } else { return size_type(prev_amount_download) << 10; } } size_type policy::peer::total_upload() const { if (connection != 0) { TORRENT_ASSERT(prev_amount_upload == 0); return connection->statistics().total_payload_upload(); } else { return size_type(prev_amount_upload) << 10; } } // this returns true if lhs is a better erase candidate than rhs bool policy::compare_peer_erase(policy::peer const& lhs, policy::peer const& rhs) const { TORRENT_ASSERT(lhs.connection == 0); TORRENT_ASSERT(rhs.connection == 0); // primarily, prefer getting rid of peers we've already tried and failed if (lhs.failcount != rhs.failcount) return lhs.failcount > rhs.failcount; bool lhs_resume_data_source = lhs.source == peer_info::resume_data; bool rhs_resume_data_source = rhs.source == peer_info::resume_data; // prefer to drop peers whose only source is resume data if (lhs_resume_data_source != rhs_resume_data_source) return lhs_resume_data_source > rhs_resume_data_source; if (lhs.connectable != rhs.connectable) return lhs.connectable < rhs.connectable; return lhs.trust_points < rhs.trust_points; } // this returns true if lhs is a better connect candidate than rhs bool policy::compare_peer(policy::peer const& lhs, policy::peer const& rhs , address const& external_ip) const { // prefer peers with lower failcount if (lhs.failcount != rhs.failcount) return lhs.failcount < rhs.failcount; // Local peers should always be tried first bool lhs_local = is_local(lhs.address()); bool rhs_local = is_local(rhs.address()); if (lhs_local != rhs_local) return lhs_local > rhs_local; if (lhs.last_connected != rhs.last_connected) return lhs.last_connected < rhs.last_connected; int lhs_rank = source_rank(lhs.source); int rhs_rank = source_rank(rhs.source); if (lhs_rank != rhs_rank) return lhs_rank > rhs_rank; #ifndef TORRENT_DISABLE_GEO_IP // don't bias fast peers when seeding if (!m_finished && m_torrent->session().has_asnum_db()) { int lhs_as = lhs.inet_as ? lhs.inet_as->second : 0; int rhs_as = rhs.inet_as ? rhs.inet_as->second : 0; if (lhs_as != rhs_as) return lhs_as > rhs_as; } #endif int lhs_distance = cidr_distance(external_ip, lhs.address()); int rhs_distance = cidr_distance(external_ip, rhs.address()); if (lhs_distance < rhs_distance) return true; return false; } }