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Implement a placeholder mechanism in the channel,id->circ map
We'll use this to help fix bug 7912, by providing a way to mark that a circuit ID can't get reused while a DESTROY is queued but not sent.
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@ -207,6 +207,61 @@ circuit_set_circid_chan_helper(circuit_t *circ, int direction,
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}
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}
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/** Mark that circuit id <b>id</b> shouldn't be used on channel <b>chan</b>,
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* even if there is no circuit on the channel. We use this to keep the
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* circuit id from getting re-used while we have queued but not yet sent
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* a destroy cell. */
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void
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channel_mark_circid_unusable(channel_t *chan, circid_t id)
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{
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chan_circid_circuit_map_t search;
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chan_circid_circuit_map_t *ent;
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/* See if there's an entry there. That wouldn't be good. */
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memset(&search, 0, sizeof(search));
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search.chan = chan;
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search.circ_id = id;
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ent = HT_FIND(chan_circid_map, &chan_circid_map, &search);
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if (ent && ent->circuit) {
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/* we have a problem. */
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log_warn(LD_BUG, "Tried to mark %u unusable on %p, but there was already "
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"a circuit there.", (unsigned)id, chan);
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} else if (ent) {
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/* It's already marked. */
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} else {
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ent = tor_malloc_zero(sizeof(chan_circid_circuit_map_t));
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ent->chan = chan;
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ent->circ_id = id;
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/* leave circuit at NULL */
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HT_INSERT(chan_circid_map, &chan_circid_map, ent);
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}
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}
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/** Mark that a circuit id <b>id</b> can be used again on <b>chan</b>.
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* We use this to re-enable the circuit ID after we've sent a destroy cell.
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*/
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void
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channel_mark_circid_usable(channel_t *chan, circid_t id)
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{
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chan_circid_circuit_map_t search;
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chan_circid_circuit_map_t *ent;
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/* See if there's an entry there. That wouldn't be good. */
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memset(&search, 0, sizeof(search));
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search.chan = chan;
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search.circ_id = id;
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ent = HT_REMOVE(chan_circid_map, &chan_circid_map, &search);
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if (ent && ent->circuit) {
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log_warn(LD_BUG, "Tried to mark %u usable on %p, but there was already "
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"a circuit there.", (unsigned)id, chan);
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return;
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}
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if (_last_circid_chan_ent == ent)
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_last_circid_chan_ent = NULL;
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tor_free(ent);
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}
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/** Set the p_conn field of a circuit <b>circ</b>, along
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* with the corresponding circuit ID, and add the circuit as appropriate
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* to the (chan,id)-\>circuit map. */
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@ -928,9 +983,13 @@ circuit_get_by_global_id(uint32_t id)
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* - circ-\>n_circ_id or circ-\>p_circ_id is equal to <b>circ_id</b>, and
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* - circ is attached to <b>chan</b>, either as p_chan or n_chan.
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* Return NULL if no such circuit exists.
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*
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* If <b>found_entry_out</b> is provided, set it to true if we have a
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* placeholder entry for circid/chan, and leave it unset otherwise.
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*/
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static INLINE circuit_t *
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circuit_get_by_circid_channel_impl(circid_t circ_id, channel_t *chan)
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circuit_get_by_circid_channel_impl(circid_t circ_id, channel_t *chan,
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int *found_entry_out)
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{
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chan_circid_circuit_map_t search;
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chan_circid_circuit_map_t *found;
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@ -951,15 +1010,21 @@ circuit_get_by_circid_channel_impl(circid_t circ_id, channel_t *chan)
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" circ_id %u, channel ID " U64_FORMAT " (%p)",
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found->circuit, (unsigned)circ_id,
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U64_PRINTF_ARG(chan->global_identifier), chan);
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if (found_entry_out)
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*found_entry_out = 1;
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return found->circuit;
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}
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log_debug(LD_CIRC,
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"circuit_get_by_circid_channel_impl() found nothing for"
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"circuit_get_by_circid_channel_impl() found %s for"
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" circ_id %u, channel ID " U64_FORMAT " (%p)",
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found ? "placeholder" : "nothing",
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(unsigned)circ_id,
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U64_PRINTF_ARG(chan->global_identifier), chan);
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if (found_entry_out)
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*found_entry_out = found ? 1 : 0;
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return NULL;
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/* The rest of this checks for bugs. Disabled by default. */
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/* We comment it out because coverity complains otherwise.
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@ -993,7 +1058,7 @@ circuit_get_by_circid_channel_impl(circid_t circ_id, channel_t *chan)
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circuit_t *
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circuit_get_by_circid_channel(circid_t circ_id, channel_t *chan)
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{
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circuit_t *circ = circuit_get_by_circid_channel_impl(circ_id, chan);
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circuit_t *circ = circuit_get_by_circid_channel_impl(circ_id, chan, NULL);
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if (!circ || circ->marked_for_close)
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return NULL;
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else
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@ -1009,7 +1074,7 @@ circuit_t *
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circuit_get_by_circid_channel_even_if_marked(circid_t circ_id,
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channel_t *chan)
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{
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return circuit_get_by_circid_channel_impl(circ_id, chan);
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return circuit_get_by_circid_channel_impl(circ_id, chan, NULL);
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}
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/** Return true iff the circuit ID <b>circ_id</b> is currently used by a
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@ -1017,7 +1082,9 @@ circuit_get_by_circid_channel_even_if_marked(circid_t circ_id,
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int
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circuit_id_in_use_on_channel(circid_t circ_id, channel_t *chan)
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{
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return circuit_get_by_circid_channel_impl(circ_id, chan) != NULL;
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int found = 0;
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return circuit_get_by_circid_channel_impl(circ_id, chan, &found) != NULL
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|| found;
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}
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/** Return the circuit that a given edge connection is using. */
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@ -1585,7 +1652,7 @@ assert_circuit_ok(const circuit_t *c)
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/* We use the _impl variant here to make sure we don't fail on marked
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* circuits, which would not be returned by the regular function. */
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circuit_t *c2 = circuit_get_by_circid_channel_impl(c->n_circ_id,
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c->n_chan);
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c->n_chan, NULL);
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tor_assert(c == c2);
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}
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}
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@ -1593,7 +1660,7 @@ assert_circuit_ok(const circuit_t *c)
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if (or_circ->p_circ_id) {
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/* ibid */
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circuit_t *c2 = circuit_get_by_circid_channel_impl(or_circ->p_circ_id,
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or_circ->p_chan);
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or_circ->p_chan, NULL);
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tor_assert(c == c2);
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}
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}
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@ -23,6 +23,8 @@ void circuit_set_p_circid_chan(or_circuit_t *circ, circid_t id,
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channel_t *chan);
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void circuit_set_n_circid_chan(circuit_t *circ, circid_t id,
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channel_t *chan);
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void channel_mark_circid_unusable(channel_t *chan, circid_t id);
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void channel_mark_circid_usable(channel_t *chan, circid_t id);
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void circuit_set_state(circuit_t *circ, uint8_t state);
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void circuit_close_all_marked(void);
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int32_t circuit_initial_package_window(void);
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