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;
}
