diff options
Diffstat (limited to 'src/or/rendclient.c')
| -rw-r--r-- | src/or/rendclient.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/src/or/rendclient.c b/src/or/rendclient.c index 48b6498133..c8f6f43f04 100644 --- a/src/or/rendclient.c +++ b/src/or/rendclient.c @@ -267,6 +267,128 @@ rend_client_introduction_acked(origin_circuit_t *circ, return 0; } +/** The period for which a hidden service directory cannot be queried for + * the same descriptor ID again. */ +#define REND_HID_SERV_DIR_REQUERY_PERIOD (15 * 60) + +/** Contains the last request times to hidden service directories for + * certain queries; keys are strings consisting of base32-encoded + * hidden service directory identities and base32-encoded descriptor IDs; + * values are pointers to timestamps of the last requests. */ +static strmap_t *last_hid_serv_requests = NULL; + +/** Look up the last request time to hidden service directory <b>hs_dir</b> + * for descriptor ID <b>desc_id_base32</b>. If <b>set</b> is non-zero, + * assign the current time <b>now</b> and return that. Otherwise, return + * the most recent request time, or 0 if no such request has been sent + * before. */ +static time_t +lookup_last_hid_serv_request(routerstatus_t *hs_dir, + const char *desc_id_base32, time_t now, int set) +{ + char hsdir_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1]; + char hsdir_desc_comb_id[2 * REND_DESC_ID_V2_LEN_BASE32 + 1]; + time_t *last_request_ptr; + base32_encode(hsdir_id_base32, sizeof(hsdir_id_base32), + hs_dir->identity_digest, DIGEST_LEN); + tor_snprintf(hsdir_desc_comb_id, sizeof(hsdir_desc_comb_id), "%s%s", + hsdir_id_base32, desc_id_base32); + if (set) { + last_request_ptr = tor_malloc_zero(sizeof(time_t *)); + *last_request_ptr = now; + strmap_set(last_hid_serv_requests, hsdir_desc_comb_id, last_request_ptr); + } else + last_request_ptr = strmap_get_lc(last_hid_serv_requests, + hsdir_desc_comb_id); + return (last_request_ptr) ? *last_request_ptr : 0; +} + +/** Clean the history of request times to hidden service directories, so that + * it does not contain requests older than REND_HID_SERV_DIR_REQUERY_PERIOD + * seconds any more. */ +static void +directory_clean_last_hid_serv_requests(void) +{ + strmap_iter_t *iter; + time_t cutoff = time(NULL) - REND_HID_SERV_DIR_REQUERY_PERIOD; + if (!last_hid_serv_requests) + last_hid_serv_requests = strmap_new(); + for (iter = strmap_iter_init(last_hid_serv_requests); + !strmap_iter_done(iter); ) { + const char *key; + void *val; + time_t *ent; + strmap_iter_get(iter, &key, &val); + ent = (time_t *) val; + if (*ent < cutoff) { + iter = strmap_iter_next_rmv(last_hid_serv_requests, iter); + tor_free(ent); + } else { + iter = strmap_iter_next(last_hid_serv_requests, iter); + } + } +} + +/** Determine the responsible hidden service directories for <b>desc_id</b> + * and fetch the descriptor belonging to that ID from one of them. Only + * send a request to hidden service directories that we did not try within + * the last REND_HID_SERV_DIR_REQUERY_PERIOD seconds; on success, return 1, + * in the case that no hidden service directory is left to ask for the + * descriptor, return 0, and in case of a failure -1. <b>query</b> is only + * passed for pretty log statements. */ +static int +directory_get_from_hs_dir(const char *desc_id, const char *query) +{ + smartlist_t *responsible_dirs = smartlist_create(); + routerstatus_t *hs_dir; + char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1]; + time_t now = time(NULL); + tor_assert(desc_id); + tor_assert(query); + tor_assert(strlen(query) == REND_SERVICE_ID_LEN_BASE32); + /* Determine responsible dirs. Even if we can't get all we want, + * work with the ones we have. If it's empty, we'll notice below. */ + (int) hid_serv_get_responsible_directories(responsible_dirs, desc_id); + + base32_encode(desc_id_base32, sizeof(desc_id_base32), + desc_id, DIGEST_LEN); + + /* Only select those hidden service directories to which we did not send + * a request recently. */ + directory_clean_last_hid_serv_requests(); /* Clean request history first. */ + + SMARTLIST_FOREACH(responsible_dirs, routerstatus_t *, dir, { + if (lookup_last_hid_serv_request(dir, desc_id_base32, 0, 0) + + REND_HID_SERV_DIR_REQUERY_PERIOD >= now) + SMARTLIST_DEL_CURRENT(responsible_dirs, dir); + }); + + hs_dir = smartlist_choose(responsible_dirs); + smartlist_free(responsible_dirs); + if (!hs_dir) { + log_info(LD_REND, "Could not pick one of the responsible hidden " + "service directories, because we requested them all " + "recently without success."); + return 0; + } + + /* Remember, that we are requesting a descriptor from this hidden service + * directory now. */ + lookup_last_hid_serv_request(hs_dir, desc_id_base32, now, 1); + + /* Send fetch request. (Pass query as payload to write it to the directory + * connection so that it can be referred to when the response arrives.) */ + directory_initiate_command_routerstatus(hs_dir, + DIR_PURPOSE_FETCH_RENDDESC_V2, + ROUTER_PURPOSE_GENERAL, + 1, desc_id_base32, query, 0, 0); + log_info(LD_REND, "Sending fetch request for v2 descriptor for " + "service '%s' with descriptor ID '%s' to hidden " + "service directory '%s' on port %d.", + query, desc_id_base32, hs_dir->nickname, hs_dir->dir_port); + return 1; +} + /** If we are not currently fetching a rendezvous service descriptor * for the service ID <b>query</b>, start a directory connection to fetch a * new one. |