/** Remove the highest priority item from ol_list[] and return it, or
* return NULL if the lists are empty.
*/
or_circuit_t *
onion_next_task(create_cell_t **onionskin_out)
{
or_circuit_t *circ;
uint16_t handshake_to_choose = decide_next_handshake_type();
onion_queue_t *head = TOR_TAILQ_FIRST(&ol_list[handshake_to_choose]);
if (!head)
return NULL; /* no onions pending, we're done */
tor_assert(head->circ);
tor_assert(head->handshake_type <= MAX_ONION_HANDSHAKE_TYPE);
// tor_assert(head->circ->p_chan); /* make sure it's still valid */
/* XXX I only commented out the above line to make the unit tests
* more manageable. That's probably not good long-term. -RD */
circ = head->circ;
if (head->onionskin)
--ol_entries[head->handshake_type];
log_info(LD_OR, "Processing create (%s). Queues now ntor=%d and tap=%d.",
head->handshake_type == ONION_HANDSHAKE_TYPE_NTOR ? "ntor" : "tap",
ol_entries[ONION_HANDSHAKE_TYPE_NTOR],
ol_entries[ONION_HANDSHAKE_TYPE_TAP]);
*onionskin_out = head->onionskin;
head->onionskin = NULL; /* prevent free. */
circ->onionqueue_entry = NULL;
onion_queue_entry_remove(head);
return circ;
}
/**
* Process all pending replies on a reply queue. The main thread should call
* this function every time the socket returned by replyqueue_get_socket() is
* readable.
*/
void
replyqueue_process(replyqueue_t *queue)
{
if (queue->alert.drain_fn(queue->alert.read_fd) < 0) {
static ratelim_t warn_limit = RATELIM_INIT(7200);
log_fn_ratelim(&warn_limit, LOG_WARN, LD_GENERAL,
"Failure from drain_fd");
}
tor_mutex_acquire(&queue->lock);
while (!TOR_TAILQ_EMPTY(&queue->answers)) {
/* lock must be held at this point.*/
workqueue_entry_t *work = TOR_TAILQ_FIRST(&queue->answers);
TOR_TAILQ_REMOVE(&queue->answers, work, next_work);
tor_mutex_release(&queue->lock);
work->on_pool = NULL;
work->reply_fn(work->arg);
workqueue_entry_free(work);
tor_mutex_acquire(&queue->lock);
}
tor_mutex_release(&queue->lock);
}
/** Add <b>circ</b> to the end of ol_list and return 0, except
* if ol_list is too long, in which case do nothing and return -1.
*/
int
onion_pending_add(or_circuit_t *circ, create_cell_t *onionskin)
{
onion_queue_t *tmp;
time_t now = time(NULL);
if (onionskin->handshake_type > MAX_ONION_HANDSHAKE_TYPE) {
log_warn(LD_BUG, "Handshake %d out of range! Dropping.",
onionskin->handshake_type);
return -1;
}
tmp = tor_malloc_zero(sizeof(onion_queue_t));
tmp->circ = circ;
tmp->handshake_type = onionskin->handshake_type;
tmp->onionskin = onionskin;
tmp->when_added = now;
if (!have_room_for_onionskin(onionskin->handshake_type)) {
#define WARN_TOO_MANY_CIRC_CREATIONS_INTERVAL (60)
static ratelim_t last_warned =
RATELIM_INIT(WARN_TOO_MANY_CIRC_CREATIONS_INTERVAL);
char *m;
if (onionskin->handshake_type == ONION_HANDSHAKE_TYPE_NTOR &&
(m = rate_limit_log(&last_warned, approx_time()))) {
log_warn(LD_GENERAL,
"Your computer is too slow to handle this many circuit "
"creation requests! Please consider using the "
"MaxAdvertisedBandwidth config option or choosing a more "
"restricted exit policy.%s",m);
tor_free(m);
}
tor_free(tmp);
return -1;
}
++ol_entries[onionskin->handshake_type];
log_info(LD_OR, "New create (%s). Queues now ntor=%d and tap=%d.",
onionskin->handshake_type == ONION_HANDSHAKE_TYPE_NTOR ? "ntor" : "tap",
ol_entries[ONION_HANDSHAKE_TYPE_NTOR],
ol_entries[ONION_HANDSHAKE_TYPE_TAP]);
circ->onionqueue_entry = tmp;
TOR_TAILQ_INSERT_TAIL(&ol_list[onionskin->handshake_type], tmp, next);
/* cull elderly requests. */
while (1) {
onion_queue_t *head = TOR_TAILQ_FIRST(&ol_list[onionskin->handshake_type]);
if (now - head->when_added < (time_t)ONIONQUEUE_WAIT_CUTOFF)
break;
circ = head->circ;
circ->onionqueue_entry = NULL;
onion_queue_entry_remove(head);
log_info(LD_CIRC,
"Circuit create request is too old; canceling due to overload.");
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_RESOURCELIMIT);
}
return 0;
}
/**
* Main function for the worker thread.
*/
static void
worker_thread_main(void *thread_)
{
workerthread_t *thread = thread_;
threadpool_t *pool = thread->in_pool;
workqueue_entry_t *work;
workqueue_reply_t result;
tor_mutex_acquire(&pool->lock);
while (1) {
/* lock must be held at this point. */
while (worker_thread_has_work(thread)) {
/* lock must be held at this point. */
if (thread->in_pool->generation != thread->generation) {
void *arg = thread->in_pool->update_args[thread->index];
thread->in_pool->update_args[thread->index] = NULL;
workqueue_reply_t (*update_fn)(void*,void*) =
thread->in_pool->update_fn;
thread->generation = thread->in_pool->generation;
tor_mutex_release(&pool->lock);
workqueue_reply_t r = update_fn(thread->state, arg);
if (r != WQ_RPL_REPLY) {
return;
}
tor_mutex_acquire(&pool->lock);
continue;
}
work = TOR_TAILQ_FIRST(&pool->work);
TOR_TAILQ_REMOVE(&pool->work, work, next_work);
work->pending = 0;
tor_mutex_release(&pool->lock);
/* We run the work function without holding the thread lock. This
* is the main thread's first opportunity to give us more work. */
result = work->fn(thread->state, work->arg);
/* Queue the reply for the main thread. */
queue_reply(thread->reply_queue, work);
/* We may need to exit the thread. */
if (result != WQ_RPL_REPLY) {
return;
}
tor_mutex_acquire(&pool->lock);
}
/* At this point the lock is held, and there is no work in this thread's
* queue. */
/* TODO: support an idle-function */
/* Okay. Now, wait till somebody has work for us. */
if (tor_cond_wait(&pool->condition, &pool->lock, NULL) < 0) {
log_warn(LD_GENERAL, "Fail tor_cond_wait.");
}
}
}
/** Remove all circuits from the pending list. Called from tor_free_all. */
void
clear_pending_onions(void)
{
onion_queue_t *victim, *next;
int i;
for (i=0; i<=MAX_ONION_HANDSHAKE_TYPE; i++) {
for (victim = TOR_TAILQ_FIRST(&ol_list[i]); victim; victim = next) {
next = TOR_TAILQ_NEXT(victim,next);
onion_queue_entry_remove(victim);
}
tor_assert(TOR_TAILQ_EMPTY(&ol_list[i]));
}
memset(ol_entries, 0, sizeof(ol_entries));
}