From 91c58013be735584acc674a60bb18d1efb38f25a Mon Sep 17 00:00:00 2001 From: Roger Dingledine Date: Wed, 13 Apr 2016 01:08:17 -0400 Subject: avoid following through on a consensus fetch if we have one already arriving --- src/or/networkstatus.c | 53 ++++++++++++++++++++++++++++++++++---------------- 1 file changed, 36 insertions(+), 17 deletions(-) (limited to 'src/or/networkstatus.c') diff --git a/src/or/networkstatus.c b/src/or/networkstatus.c index 51c985e85e..e90603e16b 100644 --- a/src/or/networkstatus.c +++ b/src/or/networkstatus.c @@ -1349,27 +1349,46 @@ networkstatus_consensus_has_excess_connections(void) return 0; } +/* Is there a consensus fetch for flavor resource that's far + * enough along to be attached to a circuit? */ +int +networkstatus_consensus_is_already_downloading(const char *resource) +{ + int answer = 0; + + /* First, get a list of all the dir conns that are fetching a consensus, + * fetching *this* consensus, and are in state "reading" (meaning they + * have already flushed their request onto the socks connection). */ + smartlist_t *fetching_conns = + connection_dir_list_by_purpose_resource_and_state( + DIR_PURPOSE_FETCH_CONSENSUS, resource, DIR_CONN_STATE_CLIENT_READING); + + /* Then, walk through each conn, to see if its linked socks connection + * is in an attached state. We have to check this separately, since with + * the optimistic data feature, fetches can send their request to the + * socks connection and go into state 'reading', even before they're + * attached to any circuit. */ + SMARTLIST_FOREACH_BEGIN(fetching_conns, dir_connection_t *, dirconn) { + /* Do any of these other dir conns have a linked socks conn that is + * attached to a circuit already? */ + connection_t *base = TO_CONN(dirconn); + if (base->linked_conn && + base->linked_conn->type == CONN_TYPE_AP && + !AP_CONN_STATE_IS_UNATTACHED(base->linked_conn->state)) + answer = 1; + } SMARTLIST_FOREACH_END(dirconn); + smartlist_free(fetching_conns); + + return answer; +} + /* Is tor currently downloading a consensus of the usable flavor? */ int networkstatus_consensus_is_downloading_usable_flavor(void) { - const char *usable_resource = networkstatus_get_flavor_name( - usable_consensus_flavor()); - const int consens_conn_usable_count = - connection_dir_count_by_purpose_and_resource( - DIR_PURPOSE_FETCH_CONSENSUS, - usable_resource); - - const int connect_consens_conn_usable_count = - connection_dir_count_by_purpose_resource_and_state( - DIR_PURPOSE_FETCH_CONSENSUS, - usable_resource, - DIR_CONN_STATE_CONNECTING); - if (connect_consens_conn_usable_count < consens_conn_usable_count) { - return 1; - } - - return 0; + const char *resource = + networkstatus_get_flavor_name(usable_consensus_flavor()); + return networkstatus_consensus_is_already_downloading(resource); } /** Given two router status entries for the same router identity, return 1 if -- cgit v1.2.3-54-g00ecf