/* Copyright (c) 2012-2018, 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/torrent_peer.hpp" #include "libtorrent/assert.hpp" #include "libtorrent/string_util.hpp" #include "libtorrent/peer_connection.hpp" #include "libtorrent/crc32c.hpp" #include "libtorrent/ip_voter.hpp" #include "libtorrent/io.hpp" // for write_uint16 namespace libtorrent { namespace { void apply_mask(std::uint8_t* b, std::uint8_t const* mask, int size) { for (int i = 0; i < size; ++i) { *b &= *mask; ++b; ++mask; } } } // 1. if the IP addresses are identical, hash the ports in 16 bit network-order // binary representation, ordered lowest first. // 2. if the IPs are in the same /24, hash the IPs ordered, lowest first. // 3. if the IPs are in the ame /16, mask the IPs by 0xffffff55, hash them // ordered, lowest first. // 4. if IPs are not in the same /16, mask the IPs by 0xffff5555, hash them // ordered, lowest first. // // * for IPv6 peers, just use the first 64 bits and widen the masks. // like this: 0xffff5555 -> 0xffffffff55555555 // the lower 64 bits are always unmasked // // * for IPv6 addresses, compare /32 and /48 instead of /16 and /24 // // * the two IP addresses that are used to calculate the rank must // always be of the same address family // // * all IP addresses are in network byte order when hashed std::uint32_t peer_priority(tcp::endpoint e1, tcp::endpoint e2) { TORRENT_ASSERT(is_v4(e1) == is_v4(e2)); using std::swap; std::uint32_t ret; if (e1.address() == e2.address()) { if (e1.port() > e2.port()) swap(e1, e2); std::uint32_t p; auto ptr = reinterpret_cast(&p); detail::write_uint16(e1.port(), ptr); detail::write_uint16(e2.port(), ptr); ret = crc32c_32(p); } else if (is_v6(e1)) { static const std::uint8_t v6mask[][8] = { { 0xff, 0xff, 0xff, 0xff, 0x55, 0x55, 0x55, 0x55 }, { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x55, 0x55 }, { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff } }; if (e1 > e2) swap(e1, e2); address_v6::bytes_type b1 = e1.address().to_v6().to_bytes(); address_v6::bytes_type b2 = e2.address().to_v6().to_bytes(); int const mask = std::memcmp(b1.data(), b2.data(), 4) ? 0 : std::memcmp(b1.data(), b2.data(), 6) ? 1 : 2; apply_mask(b1.data(), v6mask[mask], 8); apply_mask(b2.data(), v6mask[mask], 8); std::uint64_t addrbuf[4]; memcpy(&addrbuf[0], b1.data(), 16); memcpy(&addrbuf[2], b2.data(), 16); ret = crc32c(addrbuf, 4); } else { static const std::uint8_t v4mask[][4] = { { 0xff, 0xff, 0x55, 0x55 }, { 0xff, 0xff, 0xff, 0x55 }, { 0xff, 0xff, 0xff, 0xff } }; if (e1 > e2) swap(e1, e2); address_v4::bytes_type b1 = e1.address().to_v4().to_bytes(); address_v4::bytes_type b2 = e2.address().to_v4().to_bytes(); int mask = memcmp(&b1[0], &b2[0], 2) ? 0 : memcmp(&b1[0], &b2[0], 3) ? 1 : 2; apply_mask(&b1[0], v4mask[mask], 4); apply_mask(&b2[0], v4mask[mask], 4); std::uint64_t addrbuf; memcpy(&addrbuf, &b1[0], 4); memcpy(reinterpret_cast(&addrbuf) + 4, &b2[0], 4); ret = crc32c(&addrbuf, 1); } return ret; } torrent_peer::torrent_peer(std::uint16_t port_, bool conn , peer_source_flags_t const src) : prev_amount_upload(0) , prev_amount_download(0) , connection(nullptr) , peer_rank(0) , last_optimistically_unchoked(0) , last_connected(0) , port(port_) , hashfails(0) , failcount(0) , connectable(conn) , optimistically_unchoked(false) , seed(false) , fast_reconnects(0) , trust_points(0) , source(static_cast(src)) #if !defined TORRENT_DISABLE_ENCRYPTION // assume no support in order to // prefer opening non-encrypted // connections. If it fails, we'll // retry with encryption , pe_support(false) #endif , is_v6_addr(false) #if TORRENT_USE_I2P , is_i2p_addr(false) #endif , on_parole(false) , banned(false) , supports_utp(true) // assume peers support utp , confirmed_supports_utp(false) , supports_holepunch(false) , web_seed(false) {} std::uint32_t torrent_peer::rank(external_ip const& external, int external_port) const { TORRENT_ASSERT(in_use); //TODO: how do we deal with our external address changing? if (peer_rank == 0) peer_rank = peer_priority( tcp::endpoint(external.external_address(this->address()), std::uint16_t(external_port)) , tcp::endpoint(this->address(), this->port)); return peer_rank; } #ifndef TORRENT_DISABLE_LOGGING std::string torrent_peer::to_string() const { TORRENT_ASSERT(in_use); #if TORRENT_USE_I2P if (is_i2p_addr) return dest().to_string(); #endif // TORRENT_USE_I2P error_code ec; return address().to_string(ec); } #endif std::int64_t torrent_peer::total_download() const { TORRENT_ASSERT(in_use); if (connection != nullptr) { TORRENT_ASSERT(prev_amount_download == 0); return connection->statistics().total_payload_download(); } else { return std::int64_t(prev_amount_download) << 10; } } std::int64_t torrent_peer::total_upload() const { TORRENT_ASSERT(in_use); if (connection != nullptr) { TORRENT_ASSERT(prev_amount_upload == 0); return connection->statistics().total_payload_upload(); } else { return std::int64_t(prev_amount_upload) << 10; } } ipv4_peer::ipv4_peer(tcp::endpoint const& ep, bool c , peer_source_flags_t const src) : torrent_peer(ep.port(), c, src) , addr(ep.address().to_v4()) { is_v6_addr = false; #if TORRENT_USE_I2P is_i2p_addr = false; #endif } ipv4_peer::ipv4_peer(ipv4_peer const&) = default; ipv4_peer& ipv4_peer::operator=(ipv4_peer const& p) = default; #if TORRENT_USE_I2P i2p_peer::i2p_peer(string_view dest, bool connectable_ , peer_source_flags_t const src) : torrent_peer(0, connectable_, src) , destination(dest) { is_v6_addr = false; is_i2p_addr = true; } #endif // TORRENT_USE_I2P ipv6_peer::ipv6_peer(tcp::endpoint const& ep, bool c , peer_source_flags_t const src) : torrent_peer(ep.port(), c, src) , addr(ep.address().to_v6().to_bytes()) { is_v6_addr = true; #if TORRENT_USE_I2P is_i2p_addr = false; #endif } ipv6_peer::ipv6_peer(ipv6_peer const&) = default; #if TORRENT_USE_I2P string_view torrent_peer::dest() const { if (is_i2p_addr) return *static_cast(this)->destination; return ""; } #endif libtorrent::address torrent_peer::address() const { if (is_v6_addr) return libtorrent::address_v6( static_cast(this)->addr); else #if TORRENT_USE_I2P if (is_i2p_addr) return libtorrent::address(); else #endif return static_cast(this)->addr; } }