138 lines
4.5 KiB
C++
138 lines
4.5 KiB
C++
/*
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Copyright (c) 2013-2016, 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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#ifndef TORRENT_IP_VOTER_HPP_INCLUDED
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#define TORRENT_IP_VOTER_HPP_INCLUDED
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#include <vector>
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#include "libtorrent/address.hpp"
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#include "libtorrent/bloom_filter.hpp"
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#include "libtorrent/time.hpp" // for time_point
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namespace libtorrent {
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// this is an object that keeps the state for a single external IP
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// based on peoples votes
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struct TORRENT_EXTRA_EXPORT ip_voter
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{
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ip_voter();
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// returns true if a different IP is the top vote now
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// i.e. we changed our idea of what our external IP is
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bool cast_vote(address const& ip, int source_type, address const& source);
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address external_address() const { return m_external_address; }
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private:
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bool maybe_rotate();
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struct external_ip_t
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{
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external_ip_t(): sources(0), num_votes(0) {}
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bool add_vote(sha1_hash const& k, int type);
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// we want to sort descending
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bool operator<(external_ip_t const& rhs) const
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{
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if (num_votes > rhs.num_votes) return true;
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if (num_votes < rhs.num_votes) return false;
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return sources > rhs.sources;
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}
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// this is a bloom filter of the IPs that have
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// reported this address
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bloom_filter<16> voters;
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// this is the actual external address
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address addr;
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// a bitmask of sources the reporters have come from
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std::uint16_t sources;
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// the total number of votes for this IP
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std::uint16_t num_votes;
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};
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// this is a bloom filter of all the IPs that have
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// been the first to report an external address. Each
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// IP only gets to add a new item once.
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bloom_filter<32> m_external_address_voters;
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std::vector<external_ip_t> m_external_addresses;
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address m_external_address;
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// the total number of unique IPs that have voted
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int m_total_votes;
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// this is true from the first time we rotate. Before
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// we rotate for the first time, we keep updating the
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// external address as we go, since we don't have any
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// stable setting to fall back on. Once this is true,
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// we stop updating it on the fly, and just use the
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// address from when we rotated.
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bool m_valid_external;
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// the last time we rotated this ip_voter. i.e. threw
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// away all the votes and started from scratch, in case
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// our IP has changed
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time_point m_last_rotate;
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};
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// stores one address for each combination of local/global and ipv4/ipv6
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// use of this class should be avoided, get the IP from the appropriate
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// listen interface wherever possible
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struct TORRENT_EXTRA_EXPORT external_ip
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{
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external_ip()
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#if TORRENT_USE_IPV6
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: m_addresses{{address_v4(), address_v6()}, {address_v4(), address_v6()}}
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#endif
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{}
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external_ip(address const& local4, address const& global4
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, address const& local6, address const& global6);
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// the external IP as it would be observed from `ip`
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address external_address(address const& ip) const;
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private:
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// support one local and one global address per address family
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// [0][n] = global [1][n] = local
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// [n][0] = IPv4 [n][1] = IPv6
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// TODO: 1 have one instance per possible subnet, 192.168.x.x, 10.x.x.x, etc.
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address m_addresses[2][2];
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};
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}
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#endif
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