diff options
Diffstat (limited to 'src/or/connection_or.c')
| -rw-r--r-- | src/or/connection_or.c | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/src/or/connection_or.c b/src/or/connection_or.c index 8e7cd9ea51..f03b18ddf1 100644 --- a/src/or/connection_or.c +++ b/src/or/connection_or.c @@ -756,6 +756,45 @@ connection_or_update_token_buckets(smartlist_t *conns, }); } +/** How long do we wait before killing non-canonical OR connections with no + * circuits? In Tor versions up to 0.2.1.25 and 0.2.2.12-alpha, we waited 15 + * minutes before cancelling these connections, which caused fast relays to + * accrue many many idle connections. Hopefully 3-4.5 minutes is low enough + * that it kills most idle connections, without being so low that we cause + * clients to bounce on and off. + * + * For canonical connections, the limit is higher, at 15-22.5 minutes. + * + * For each OR connection, we randomly add up to 50% extra to its idle_timeout + * field, to avoid exposing when exactly the last circuit closed. Since we're + * storing idle_timeout in a uint16_t, don't let these values get higher than + * 12 hours or so without revising connection_or_set_canonical and/or expanding + * idle_timeout. + */ +#define IDLE_OR_CONN_TIMEOUT_NONCANONICAL 180 +#define IDLE_OR_CONN_TIMEOUT_CANONICAL 900 + +/* Mark <b>or_conn</b> as canonical if <b>is_canonical</b> is set, and + * non-canonical otherwise. Adjust idle_timeout accordingly. + */ +void +connection_or_set_canonical(or_connection_t *or_conn, + int is_canonical) +{ + const unsigned int timeout_base = is_canonical ? + IDLE_OR_CONN_TIMEOUT_CANONICAL : IDLE_OR_CONN_TIMEOUT_NONCANONICAL; + + if (bool_eq(is_canonical, or_conn->is_canonical) && + or_conn->idle_timeout != 0) { + /* Don't recalculate an existing idle_timeout unless the canonical + * status changed. */ + return; + } + + or_conn->is_canonical = !! is_canonical; /* force to a 1-bit boolean */ + or_conn->idle_timeout = timeout_base + crypto_rand_int(timeout_base / 2); +} + /** If we don't necessarily know the router we're connecting to, but we * have an addr/port/id_digest, then fill in as much as we can. Start * by checking to see if this describes a router we know. @@ -780,7 +819,7 @@ connection_or_init_conn_from_address(or_connection_t *conn, /* XXXX proposal 186 is making this more complex. For now, a conn is canonical when it uses the _preferred_ address. */ if (tor_addr_eq(&conn->base_.addr, &node_ap.addr)) - conn->is_canonical = 1; + connection_or_set_canonical(conn, 1); if (!started_here) { /* Override the addr/port, so our log messages will make sense. * This is dangerous, since if we ever try looking up a conn by |