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[tor-commits] [tor/release-0.2.8] close other consensus fetches when we get a consensus
commit a7665df2f8607403e5e14bf1af7426cedfea01dc
Author: Roger Dingledine <arma@xxxxxxxxxxxxxx>
Date: Wed Apr 13 02:54:31 2016 -0400
close other consensus fetches when we get a consensus
not once per second, and only do it when a consensus arrives
---
src/or/directory.c | 123 +++++++++++++----------------------------------------
src/or/directory.h | 1 -
src/or/main.c | 11 -----
3 files changed, 30 insertions(+), 105 deletions(-)
diff --git a/src/or/directory.c b/src/or/directory.c
index 8486c8c..02db035 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -96,6 +96,9 @@ static void directory_initiate_command_rend(
time_t if_modified_since,
const rend_data_t *rend_query);
+static void connection_dir_close_consensus_fetches(
+ dir_connection_t *except_this_one, const char *resource);
+
/********* START VARIABLES **********/
/** How far in the future do we allow a directory server to tell us it is
@@ -2028,6 +2031,10 @@ connection_dir_client_reached_eof(dir_connection_t *conn)
networkstatus_consensus_download_failed(0, flavname);
return -1;
}
+
+ /* If we launched other fetches for this consensus, cancel them. */
+ connection_dir_close_consensus_fetches(conn, flavname);
+
/* launches router downloads as needed */
routers_update_all_from_networkstatus(now, 3);
update_microdescs_from_networkstatus(now);
@@ -3680,7 +3687,7 @@ connection_dir_finished_flushing(dir_connection_t *conn)
}
/* A helper function for connection_dir_close_consensus_conn_if_extra()
- * and connection_dir_close_extra_consensus_conns() that returns 0 if
+ * that returns 0 if
* we can't have, or don't want to close, excess consensus connections. */
STATIC int
connection_dir_would_close_consensus_conn_helper(void)
@@ -3797,103 +3804,33 @@ connection_dir_close_consensus_conn_if_extra(dir_connection_t *conn)
return 0;
}
-/* Clean up excess consensus download connection attempts.
- * During bootstrap, or when the bootstrap consensus has just been downloaded,
- * if we have more than one active consensus connection:
- * - if we don't have a consensus, and we're downloading a consensus, keep an
- * earlier connection, or a connection to a fallback directory, and close
- * all other connections;
- * - if we have just downloaded the bootstrap consensus, and have other
- * consensus connections left over, close all of them.
+/* We just got a new consensus! If there are other in-progress requests
+ * for this consensus flavor (for example because we launched several in
+ * parallel), cancel them.
*
- * Post-bootstrap consensus connection attempts are initiated one at a time.
- * So this function won't close any consensus connection attempts that
- * are initiated after bootstrap.
+ * We do this check here (not just in
+ * connection_ap_handshake_attach_circuit()) to handle the edge case where
+ * a consensus fetch begins and ends before some other one tries to attach to
+ * a circuit, in which case the other one won't know that we're all happy now.
+ *
+ * Don't mark the conn that just gave us the consensus -- otherwise we
+ * would end up double-marking it when it cleans itself up.
*/
-void
-connection_dir_close_extra_consensus_conns(void)
+static void
+connection_dir_close_consensus_fetches(dir_connection_t *except_this_one,
+ const char *resource)
{
- /* Only cleanup connections if there is more than one consensus connection,
- * and at least one of those connections is already downloading
- * (during bootstrap), or connecting (just after the bootstrap consensus is
- * downloaded).
- * Post-bootstrap consensus connection attempts won't be cleaned up, because
- * they only occur one at a time. */
- if (!connection_dir_would_close_consensus_conn_helper()) {
- return;
- }
-
- int we_are_bootstrapping = networkstatus_consensus_is_bootstrapping(
- time(NULL));
-
- const char *usable_resource = networkstatus_get_flavor_name(
- usable_consensus_flavor());
- smartlist_t *consens_usable_conns =
- connection_dir_list_by_purpose_and_resource(
- DIR_PURPOSE_FETCH_CONSENSUS,
- usable_resource);
-
- /* If we want to keep a connection that's downloading, find a connection to
- * keep, favouring:
- * - connections opened earlier (they are likely to have progressed further)
- * - connections to fallbacks (to reduce the load on authorities) */
- dir_connection_t *kept_download_conn = NULL;
- int kept_is_authority = 0;
- if (we_are_bootstrapping) {
- SMARTLIST_FOREACH_BEGIN(consens_usable_conns,
- dir_connection_t *, d) {
- tor_assert(d);
- int d_is_authority = router_digest_is_trusted_dir(d->identity_digest);
- /* keep the first connection that is past the connecting state, but
- * prefer fallbacks. */
- if (d->base_.state != DIR_CONN_STATE_CONNECTING) {
- if (!kept_download_conn || (kept_is_authority && !d_is_authority)) {
- kept_download_conn = d;
- kept_is_authority = d_is_authority;
- /* we've found the earliest fallback, and want to keep it regardless
- * of any other connections */
- if (!kept_is_authority)
- break;
- }
- }
- } SMARTLIST_FOREACH_END(d);
- }
-
- SMARTLIST_FOREACH_BEGIN(consens_usable_conns,
- dir_connection_t *, d) {
- tor_assert(d);
- /* don't close this connection if it's the one we want to keep */
- if (kept_download_conn && d == kept_download_conn)
+ smartlist_t *conns_to_close =
+ connection_dir_list_by_purpose_and_resource(DIR_PURPOSE_FETCH_CONSENSUS,
+ resource);
+ SMARTLIST_FOREACH_BEGIN(conns_to_close, dir_connection_t *, d) {
+ if (d == except_this_one)
continue;
- /* mark all other connections for close */
- if (!d->base_.marked_for_close) {
- connection_close_immediate(&d->base_);
- connection_mark_for_close(&d->base_);
- }
+ log_info(LD_DIR, "Closing consensus fetch (to %s) since one "
+ "has just arrived.", TO_CONN(d)->address);
+ connection_mark_for_close(TO_CONN(d));
} SMARTLIST_FOREACH_END(d);
-
- smartlist_free(consens_usable_conns);
- consens_usable_conns = NULL;
-
- /* make sure we've closed all excess connections */
- const int final_connecting_conn_count =
- connection_dir_count_by_purpose_resource_and_state(
- DIR_PURPOSE_FETCH_CONSENSUS,
- usable_resource,
- DIR_CONN_STATE_CONNECTING);
- if (final_connecting_conn_count > 0) {
- log_warn(LD_BUG, "Expected 0 consensus connections connecting after "
- "cleanup, got %d.", final_connecting_conn_count);
- }
- const int expected_final_conn_count = (we_are_bootstrapping ? 1 : 0);
- const int final_conn_count =
- connection_dir_count_by_purpose_and_resource(
- DIR_PURPOSE_FETCH_CONSENSUS,
- usable_resource);
- if (final_conn_count > expected_final_conn_count) {
- log_warn(LD_BUG, "Expected %d consensus connections after cleanup, got "
- "%d.", expected_final_conn_count, final_connecting_conn_count);
- }
+ smartlist_free(conns_to_close);
}
/** Connected handler for directory connections: begin sending data to the
diff --git a/src/or/directory.h b/src/or/directory.h
index c4edbb5..9a17474 100644
--- a/src/or/directory.h
+++ b/src/or/directory.h
@@ -80,7 +80,6 @@ void directory_initiate_command(const tor_addr_t *or_addr, uint16_t or_port,
time_t if_modified_since);
int connection_dir_avoid_extra_connection_for_purpose(unsigned int purpose);
int connection_dir_close_consensus_conn_if_extra(dir_connection_t *conn);
-void connection_dir_close_extra_consensus_conns(void);
#define DSR_HEX (1<<0)
#define DSR_BASE64 (1<<1)
diff --git a/src/or/main.c b/src/or/main.c
index bf5b2b8..3d84de6 100644
--- a/src/or/main.c
+++ b/src/or/main.c
@@ -1484,17 +1484,6 @@ run_scheduled_events(time_t now)
dirvote_act(options, now);
}
- /* 2d. Cleanup excess consensus bootstrap connections every second.
- * connection_dir_close_consensus_conn_if_extra() closes some connections
- * that are clearly excess, but this check is more thorough.
- * This only closes connections if there is more than one consensus
- * connection, and at least one of those connections is already downloading
- * (during bootstrap), or connecting (just after the bootstrap consensus is
- * downloaded).
- * It won't close any consensus connections initiated after bootstrap,
- * because those attempts are made one at a time. */
- connection_dir_close_extra_consensus_conns();
-
/* 3a. Every second, we examine pending circuits and prune the
* ones which have been pending for more than a few seconds.
* We do this before step 4, so it can try building more if
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