commit 0c8e042c30946faa564f03251bb3663e6204df9a Author: Nick Mathewson nickm@torproject.org Date: Wed Nov 11 13:34:05 2015 -0500

Restore semantics of advertise vs serve on directory cacheing

When we are low on accounted bandwidth, we stop advertising that we're a directory, but we will continue to answer directory requests, just as before. --- src/or/router.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/src/or/router.c b/src/or/router.c index 5c680ce..c1d970d 100644 --- a/src/or/router.c +++ b/src/or/router.c @@ -1099,11 +1099,26 @@ check_whether_dirport_reachable(void) can_reach_dir_port; }

-/** The lower threshold of remaining bandwidth required to advertise directory - * services */ +/** The lower threshold of remaining bandwidth required to advertise (or + * automatically provide) directory services */ /* XXX Should this be increased? */ #define MIN_BW_TO_ADVERTISE_DIRSERVER 51200

+/** Return true iff we have enough configured bandwidth to cache directory + * information. */ +static int +router_has_bandwidth_to_be_dirserver(const or_options_t *options) +{ + if (options->BandwidthRate < MIN_BW_TO_ADVERTISE_DIRSERVER) { + return 0; + } + if (options->RelayBandwidthRate > 0 && + options->RelayBandwidthRate < MIN_BW_TO_ADVERTISE_DIRSERVER) { + return 0; + } + return 1; +} + /** Helper: Return 1 if we have sufficient resources for serving directory * requests, return 0 otherwise. * dir_port is either 0 or the configured DirPort number. @@ -1144,9 +1159,7 @@ router_should_be_directory_server(const or_options_t *options, int dir_port) new_choice = 0; reason = "AccountingMax enabled"; } - } else if (options->BandwidthRate < MIN_BW_TO_ADVERTISE_DIRSERVER || - (options->RelayBandwidthRate > 0 && - options->RelayBandwidthRate < MIN_BW_TO_ADVERTISE_DIRSERVER)) { + } else if (! router_has_bandwidth_to_be_dirserver(options)) { /* if we're advertising a small amount */ new_choice = 0; reason = "BandwidthRate under 50KB"; @@ -1178,8 +1191,8 @@ dir_server_mode(const or_options_t *options) { if (!options->DirCache) return 0; - return (server_mode(options) || options->DirPort_set) && - router_should_be_directory_server(options, 0); + return options->DirPort_set || + (server_mode(options) && router_has_bandwidth_to_be_dirserver(options)); }

/** Look at a variety of factors, and return 0 if we don't want to @@ -1899,7 +1912,8 @@ router_build_fresh_descriptor(routerinfo_t **r, extrainfo_t **e) ri->addr = addr; ri->or_port = router_get_advertised_or_port(options); ri->dir_port = router_get_advertised_dir_port(options, 0); - ri->supports_tunnelled_dir_requests = dir_server_mode(options); + ri->supports_tunnelled_dir_requests = dir_server_mode(options) && + router_should_be_directory_server(options, ri->dir_port); ri->cache_info.published_on = time(NULL); ri->onion_pkey = crypto_pk_dup_key(get_onion_key()); /* must invoke from * main thread */