127 lines
4.3 KiB
C++
127 lines
4.3 KiB
C++
/*
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Copyright (c) 2013, Arvid Norberg
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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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#include "libtorrent/ip_voter.hpp"
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#include "libtorrent/broadcast_socket.hpp" // for is_any() etc.
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#include "libtorrent/socket_io.hpp" // for hash_address
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#include "libtorrent/random.hpp" // for random()
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#include <boost/bind.hpp>
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namespace libtorrent
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{
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bool ip_voter::cast_vote(address const& ip
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, int source_type, address const& source)
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{
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if (is_any(ip)) return false;
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if (is_local(ip)) return false;
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if (is_loopback(ip)) return false;
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// don't trust source that aren't connected to us
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// on a different address family than the external
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// IP they claim we have
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if (ip.is_v4() != source.is_v4()) return false;
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// this is the key to use for the bloom filters
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// it represents the identity of the voter
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sha1_hash k;
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hash_address(source, k);
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// do we already have an entry for this external IP?
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std::vector<external_ip_t>::iterator i = std::find_if(m_external_addresses.begin()
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, m_external_addresses.end(), boost::bind(&external_ip_t::addr, _1) == ip);
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if (i == m_external_addresses.end())
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{
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// each IP only gets to add a new IP once
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if (m_external_address_voters.find(k)) return false;
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if (m_external_addresses.size() > 40)
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{
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if (random() % 100 < 50)
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return false;
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// use stable sort here to maintain the fifo-order
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// of the entries with the same number of votes
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// this will sort in ascending order, i.e. the lowest
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// votes first. Also, the oldest are first, so this
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// is a sort of weighted LRU.
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std::stable_sort(m_external_addresses.begin(), m_external_addresses.end());
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// erase the first element, since this is the
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// oldest entry and the one with lowst number
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// of votes. This makes sense because the oldest
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// entry has had the longest time to receive more
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// votes to be bumped up
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m_external_addresses.erase(m_external_addresses.begin());
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}
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m_external_addresses.push_back(external_ip_t());
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i = m_external_addresses.end() - 1;
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i->addr = ip;
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}
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// add one more vote to this external IP
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if (!i->add_vote(k, source_type)) return false;
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i = std::max_element(m_external_addresses.begin(), m_external_addresses.end());
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TORRENT_ASSERT(i != m_external_addresses.end());
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if (i->addr == m_external_address) return false;
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m_external_address = i->addr;
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m_external_address_voters.clear();
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return true;
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}
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bool ip_voter::external_ip_t::add_vote(sha1_hash const& k, int type)
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{
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sources |= type;
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if (voters.find(k)) return false;
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voters.set(k);
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++num_votes;
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return true;
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}
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bool external_ip::cast_vote(address const& ip, int source_type, address const& source)
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{
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return m_vote_group[ip.is_v6()].cast_vote(ip, source_type, source);
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}
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address external_ip::external_address(address const& ip) const
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{
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address ext = m_vote_group[ip.is_v6()].external_address();
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if (ip.is_v6() && ext == address_v4()) return address_v6();
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return ext;
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}
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}
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