diff --git a/changes/close_begindir_circs b/changes/close_begindir_circs new file mode 100644 index 0000000000..3b1ee879c5 --- /dev/null +++ b/changes/close_begindir_circs @@ -0,0 +1,7 @@ + o Major bugfixes: + - Relays now close idle circuits early if it looks like they were + intended for directory fetches. Such circuits are unlikely to + be re-used, and tens of thousands of them were piling up at the + fast relays, causing the relays to run out of sockets and memory. + Bugfix on 0.2.0.22-rc (where clients started tunneling their + directory fetches over TLS). diff --git a/src/or/circuituse.c b/src/or/circuituse.c index 6ae2769a60..827c4bbf2b 100644 --- a/src/or/circuituse.c +++ b/src/or/circuituse.c @@ -17,7 +17,7 @@ extern circuit_t *global_circuitlist; /* from circuitlist.c */ /********* END VARIABLES ************/ -static void circuit_expire_old_circuits(time_t now); +static void circuit_expire_old_circuits_clientside(time_t now); static void circuit_increment_failure_count(void); /** Return 1 if circ could be returned by circuit_get_best(). @@ -544,7 +544,7 @@ circuit_build_needed_circs(time_t now) time_to_new_circuit = now + options->NewCircuitPeriod; if (proxy_mode(get_options())) addressmap_clean(now); - circuit_expire_old_circuits(now); + circuit_expire_old_circuits_clientside(now); #if 0 /* disable for now, until predict-and-launch-new can cull leftovers */ circ = circuit_get_youngest_clean_open(CIRCUIT_PURPOSE_C_GENERAL); @@ -628,7 +628,7 @@ circuit_detach_stream(circuit_t *circ, edge_connection_t *conn) * for too long and has no streams on it: mark it for close. */ static void -circuit_expire_old_circuits(time_t now) +circuit_expire_old_circuits_clientside(time_t now) { circuit_t *circ; time_t cutoff = now - get_options()->CircuitIdleTimeout; @@ -660,6 +660,53 @@ circuit_expire_old_circuits(time_t now) } } +/** How long do we wait before killing circuits with the properties + * described below? + * + * Probably we could choose a number here as low as 5 to 10 seconds, + * since these circs are used for begindir, and a) generally you either + * ask another begindir question right after or you don't for a long time, + * b) clients at least through 0.2.1.x choose from the whole set of + * directory mirrors at each choice, and c) re-establishing a one-hop + * circuit via create-fast is a light operation assuming the TLS conn is + * still there. + * + * I expect "b" to go away one day when we move to using directory + * guards, but I think "a" and "c" are good enough reasons that a low + * number is safe even then. + */ +#define IDLE_ONE_HOP_CIRC_TIMEOUT 60 + +/** Find each non-origin circuit that has been unused for too long, + * has no streams on it, used a create_fast, and ends here: mark it + * for close. + */ +void +circuit_expire_old_circuits_serverside(time_t now) +{ + circuit_t *circ; + or_circuit_t *or_circ; + time_t cutoff = now - IDLE_ONE_HOP_CIRC_TIMEOUT; + + for (circ = global_circuitlist; circ; circ = circ->next) { + if (circ->marked_for_close || CIRCUIT_IS_ORIGIN(circ)) + continue; + or_circ = TO_OR_CIRCUIT(circ); + /* If the circuit has been idle for too long, and there are no streams + * on it, and it ends here, and it used a create_fast, mark it for close. + */ + if (or_circ->is_first_hop && !circ->n_conn && + !or_circ->n_streams && !or_circ->resolving_streams && + or_circ->p_conn && + or_circ->p_conn->timestamp_last_added_nonpadding <= cutoff) { + log_info(LD_CIRC, "Closing circ_id %d (empty %d secs ago)", + or_circ->p_circ_id, + (int)(now - or_circ->p_conn->timestamp_last_added_nonpadding)); + circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED); + } + } +} + /** Number of testing circuits we want open before testing our bandwidth. */ #define NUM_PARALLEL_TESTING_CIRCS 4 diff --git a/src/or/main.c b/src/or/main.c index 9b57ce8728..04364bbe10 100644 --- a/src/or/main.c +++ b/src/or/main.c @@ -1058,6 +1058,10 @@ run_scheduled_events(time_t now) if (have_dir_info && !we_are_hibernating()) circuit_build_needed_circs(now); + /* every 10 seconds, but not at the same second as other such events */ + if (now % 10 == 5) + circuit_expire_old_circuits_serverside(now); + /** 5. We do housekeeping for each connection... */ connection_or_set_bad_connections(); for (i=0;i