bool dht_tracker::incoming_packet(udp::endpoint const& ep , span<char const> const buf) { int const buf_size = int(buf.size()); if (buf_size <= 20 || buf.front() != 'd' || buf.back() != 'e') return false; m_counters.inc_stats_counter(counters::dht_bytes_in, buf_size); // account for IP and UDP overhead m_counters.inc_stats_counter(counters::recv_ip_overhead_bytes , ep.address().is_v6() ? 48 : 28); m_counters.inc_stats_counter(counters::dht_messages_in); if (m_settings.ignore_dark_internet && ep.address().is_v4()) { address_v4::bytes_type b = ep.address().to_v4().to_bytes(); // these are class A networks not available to the public // if we receive messages from here, that seems suspicious static std::uint8_t const class_a[] = { 3, 6, 7, 9, 11, 19, 21, 22, 25 , 26, 28, 29, 30, 33, 34, 48, 51, 56 }; if (std::find(std::begin(class_a), std::end(class_a), b[0]) != std::end(class_a)) { m_counters.inc_stats_counter(counters::dht_messages_in_dropped); return true; } } if (!m_blocker.incoming(ep.address(), clock_type::now(), m_log)) { m_counters.inc_stats_counter(counters::dht_messages_in_dropped); return true; } TORRENT_ASSERT(buf_size > 0); int pos; error_code err; int ret = bdecode(buf.data(), buf.data() + buf_size, m_msg, err, &pos, 10, 500); if (ret != 0) { m_counters.inc_stats_counter(counters::dht_messages_in_dropped); #ifndef TORRENT_DISABLE_LOGGING m_log->log_packet(dht_logger::incoming_message, buf, ep); #endif return false; } if (m_msg.type() != bdecode_node::dict_t) { m_counters.inc_stats_counter(counters::dht_messages_in_dropped); #ifndef TORRENT_DISABLE_LOGGING m_log->log_packet(dht_logger::incoming_message, buf, ep); #endif // it's not a good idea to send a response to an invalid messages return false; } #ifndef TORRENT_DISABLE_LOGGING m_log->log_packet(dht_logger::incoming_message, buf, ep); #endif libtorrent::dht::msg m(m_msg, ep); m_dht.incoming(m); #if TORRENT_USE_IPV6 m_dht6.incoming(m); #endif return true; }