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Don't touch a QUIC connection's state after it is gone #182

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Merged
jagerman merged 3 commits into from
Oct 7, 2026
Merged

Don't touch a QUIC connection's state after it is gone #182

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74585a0
Don't dereference a connection that is already gone when a response a…
mpretty-cyro Oct 6, 2026
d72c8bc
Clear only the closed connection's state when a connection fails
mpretty-cyro Oct 6, 2026
0ce0972
Say accurately when a response can arrive after its connection is gone
jagerman Oct 7, 2026
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3 changes: 2 additions & 1 deletion include/session/network/transport/quic_transport.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,8 @@ class QuicTransport : public ITransport, public std::enable_shared_from_this<Qui
const std::string& address_pubkey_hex,
const std::string& initiating_req_id,
std::optional<uint64_t> error_code,
std::optional<std::string> custom_error);
std::optional<std::string> custom_error,
std::optional<oxen::quic::ConnectionID> conn_id = std::nullopt);
};

} // namespace session::network
42 changes: 31 additions & 11 deletions src/network/transport/quic_transport.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -371,10 +371,14 @@ void QuicTransport::_establish_connection(
}
},
[weak_self = weak_from_this(), address_pubkey_hex, initiating_req_id](
oxen::quic::Connection&, uint64_t error_code) {
oxen::quic::Connection& conn, uint64_t error_code) {
if (auto self = weak_self.lock())
self->_fail_connection(
address_pubkey_hex, initiating_req_id, error_code, std::nullopt);
address_pubkey_hex,
initiating_req_id,
error_code,
std::nullopt,
conn.reference_id());
});
} catch (const std::exception& e) {
_fail_connection(address_pubkey_hex, initiating_req_id, std::nullopt, e.what());
Expand Down Expand Up @@ -510,13 +514,20 @@ void QuicTransport::_send_on_connection(
// Since the request completed it's round-trip if it isn't the "reserverd" stream
// (not used for general requests) then we can either add it back to the pool, or
// close it if there are more that the active stream price limit
//
// The connection can be gone by the time this runs, e.g. if the stream outlived it
// (libquic then fails the request from ~sent_request). Then there is nothing to
// return to the pool or close, and any ids pooled for it are dead too.
if (stream_id != 0 && _endpoint) {
auto conn = _endpoint->get_conn(conn_id);

if (conn && conn->get_streams_available() <= ACTIVE_STREAM_PRUNE_LIMIT)
_available_stream_ids[conn_id].insert(stream_id);
else if (auto stream = conn->get_stream<oxen::quic::BTRequestStream>(stream_id))
stream->close();
if (auto conn = _endpoint->get_conn(conn_id)) {
if (conn->get_streams_available() <= ACTIVE_STREAM_PRUNE_LIMIT)
_available_stream_ids[conn_id].insert(stream_id);
else if (
auto stream =
conn->get_stream<oxen::quic::BTRequestStream>(stream_id))
stream->close();
} else
_available_stream_ids.erase(conn_id);
}

if (resp.timed_out) {
Expand Down Expand Up @@ -562,7 +573,8 @@ void QuicTransport::_fail_connection(
const std::string& address_pubkey_hex,
const std::string& initiating_req_id,
std::optional<uint64_t> error_code,
std::optional<std::string> custom_error) {
std::optional<std::string> custom_error,
std::optional<oxen::quic::ConnectionID> conn_id) {
if (error_code == NGTCP2_NO_ERROR)
log::info(
cat,
Expand Down Expand Up @@ -605,8 +617,16 @@ void QuicTransport::_fail_connection(
address_pubkey_hex,
custom_error.value_or("Unknown error"));

// Clear the connection and stream ids
if (auto id = _active_connection_ids.extract(address_pubkey_hex))
// Clear the connection and stream ids. When the closed connection is known, only its own
// state goes: a newer connection to the same node can be established before an old one's close
// arrives, and clearing by pubkey alone would drop the new connection and orphan the old one's
// stream ids.
if (conn_id) {
_available_stream_ids.erase(*conn_id);
if (auto it = _active_connection_ids.find(address_pubkey_hex);
it != _active_connection_ids.end() && it->second == *conn_id)
_active_connection_ids.erase(it);
} else if (auto id = _active_connection_ids.extract(address_pubkey_hex))
_available_stream_ids.erase(id.mapped());

// Process any waiting verification requests
Expand Down