// prevent request means that the total number of requests has
// overflown. This query failed because it was the oldest one.
// So, if this is true, don't make another request
void traversal_algorithm::failed(observer_ptr o, int flags)
{
TORRENT_ASSERT(m_invoke_count >= 0);
if (m_results.empty()) return;
TORRENT_ASSERT(o->flags & observer::flag_queried);
if (flags & short_timeout)
{
// short timeout means that it has been more than
// two seconds since we sent the request, and that
// we'll most likely not get a response. But, in case
// we do get a late response, keep the handler
// around for some more, but open up the slot
// by increasing the branch factor
if ((o->flags & observer::flag_short_timeout) == 0)
++m_branch_factor;
o->flags |= observer::flag_short_timeout;
#ifdef TORRENT_DHT_VERBOSE_LOGGING
TORRENT_LOG(traversal) << "[" << this << "] 1ST_TIMEOUT "
<< " id: " << o->id()
<< " distance: " << distance_exp(m_target, o->id())
<< " addr: " << o->target_ep()
<< " branch-factor: " << m_branch_factor
<< " invoke-count: " << m_invoke_count;
#endif
}
else
{
o->flags |= observer::flag_failed;
// if this flag is set, it means we increased the
// branch factor for it, and we should restore it
if (o->flags & observer::flag_short_timeout)
--m_branch_factor;
#ifdef TORRENT_DHT_VERBOSE_LOGGING
TORRENT_LOG(traversal) << "[" << this << "] TIMEOUT "
<< " id: " << o->id()
<< " distance: " << distance_exp(m_target, o->id())
<< " addr: " << o->target_ep()
<< " branch-factor: " << m_branch_factor
<< " invoke-count: " << m_invoke_count;
#endif
// don't tell the routing table about
// node ids that we just generated ourself
if ((o->flags & observer::flag_no_id) == 0)
m_node.m_table.node_failed(o->id(), o->target_ep());
++m_timeouts;
--m_invoke_count;
TORRENT_ASSERT(m_invoke_count >= 0);
}
if (flags & prevent_request)
{
--m_branch_factor;
if (m_branch_factor <= 0) m_branch_factor = 1;
}
bool is_done = add_requests();
if (is_done) done();
}
bool obfuscated_get_peers::invoke(observer_ptr o)
{
if (!m_obfuscated) return get_peers::invoke(o);
const node_id id = o->id();
const int shared_prefix = 160 - distance_exp(id, m_target);
// when we get close to the target zone in the DHT
// start using the correct info-hash, in order to
// start receiving peers
if (shared_prefix > m_node.m_table.depth() - 4)
{
m_obfuscated = false;
// clear the queried bits on all successful nodes in
// our node-list for this traversal algorithm, to
// allow the get_peers traversal to regress in case
// nodes further down end up being dead
for (std::vector<observer_ptr>::iterator i = m_results.begin()
, end(m_results.end()); i != end; ++i)
{
observer* const node = i->get();
// don't re-request from nodes that didn't respond
if (node->flags & observer::flag_failed) continue;
// don't interrupt with queries that are already in-flight
if ((node->flags & observer::flag_alive) == 0) continue;
node->flags &= ~(observer::flag_queried | observer::flag_alive);
}
return get_peers::invoke(o);
}
entry e;
e["y"] = "q";
e["q"] = "get_peers";
entry& a = e["a"];
// This logic will obfuscate the target info-hash
// we're looking up, in order to preserve more privacy
// on the DHT. This is done by only including enough
// bits in the info-hash for the node we're querying to
// give a good answer, but not more.
// now, obfuscate the bits past shared_prefix + 3
node_id mask = generate_prefix_mask(shared_prefix + 3);
node_id obfuscated_target = generate_random_id() & ~mask;
obfuscated_target |= m_target & mask;
a["info_hash"] = obfuscated_target.to_string();
if (m_node.observer())
{
m_node.observer()->outgoing_get_peers(m_target, obfuscated_target
, o->target_ep());
}
m_node.stats_counters().inc_stats_counter(counters::dht_get_peers_out);
return m_node.m_rpc.invoke(e, o->target_ep(), o);
}
bool find_data::invoke(observer_ptr o)
{
if (m_done)
{
m_invoke_count = -1;
return false;
}
// send request to find closer nodes
kademlia2_req req;
req.kid_receiver = o->id();
req.kid_target = m_target;
req.search_type = m_search_type;
o->m_packet_id = m_target; // bind observer to correspond packet
return m_node.m_rpc.invoke(req, o->target_ep(), o);
}
// prevent request means that the total number of requests has
// overflown. This query failed because it was the oldest one.
// So, if this is true, don't make another request
void traversal_algorithm::failed(observer_ptr o, int const flags)
{
// don't tell the routing table about
// node ids that we just generated ourself
if ((o->flags & observer::flag_no_id) == 0)
m_node.m_table.node_failed(o->id(), o->target_ep());
if (m_results.empty()) return;
bool decrement_branch_factor = false;
TORRENT_ASSERT(o->flags & observer::flag_queried);
if (flags & short_timeout)
{
// short timeout means that it has been more than
// two seconds since we sent the request, and that
// we'll most likely not get a response. But, in case
// we do get a late response, keep the handler
// around for some more, but open up the slot
// by increasing the branch factor
if ((o->flags & observer::flag_short_timeout) == 0)
{
TORRENT_ASSERT(m_branch_factor < (std::numeric_limits<std::int16_t>::max)());
++m_branch_factor;
}
o->flags |= observer::flag_short_timeout;
#ifndef TORRENT_DISABLE_LOGGING
dht_observer* logger = get_node().observer();
if (logger != nullptr && logger->should_log(dht_logger::traversal))
{
char hex_id[41];
aux::to_hex(o->id(), hex_id);
logger->log(dht_logger::traversal
, "[%p] 1ST_TIMEOUT id: %s distance: %d addr: %s branch-factor: %d "
"invoke-count: %d type: %s"
, static_cast<void*>(this), hex_id, distance_exp(m_target, o->id())
, print_address(o->target_addr()).c_str(), m_branch_factor
, m_invoke_count, name());
}
#endif
}
else
{
o->flags |= observer::flag_failed;
// if this flag is set, it means we increased the
// branch factor for it, and we should restore it
decrement_branch_factor = (o->flags & observer::flag_short_timeout) != 0;
#ifndef TORRENT_DISABLE_LOGGING
dht_observer* logger = get_node().observer();
if (logger != nullptr && logger->should_log(dht_logger::traversal))
{
char hex_id[41];
aux::to_hex(o->id(), hex_id);
logger->log(dht_logger::traversal
, "[%p] TIMEOUT id: %s distance: %d addr: %s branch-factor: %d "
"invoke-count: %d type: %s"
, static_cast<void*>(this), hex_id, distance_exp(m_target, o->id())
, print_address(o->target_addr()).c_str(), m_branch_factor
, m_invoke_count, name());
}
#endif
++m_timeouts;
TORRENT_ASSERT(m_invoke_count > 0);
--m_invoke_count;
}
// this is another reason to decrement the branch factor, to prevent another
// request from filling this slot. Only ever decrement once per response though
decrement_branch_factor |= (flags & prevent_request);
if (decrement_branch_factor)
{
TORRENT_ASSERT(m_branch_factor > 0);
--m_branch_factor;
if (m_branch_factor <= 0) m_branch_factor = 1;
}
bool const is_done = add_requests();
if (is_done) done();
}
