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author | George Kadianakis <desnacked@riseup.net> | 2017-06-01 13:48:03 +0300 |
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committer | David Goulet <dgoulet@torproject.org> | 2017-08-24 13:03:27 -0400 |
commit | 912c11761c5b5b0a80e232bdc96788677300ca67 (patch) | |
tree | fa1eb7a0ef856a51d3b3148d2d8ec4d74200b20b /src/or/hs_common.c | |
parent | 7aef3ec0fde0b320343ecb3aa7080b6e1d9a2e62 (diff) | |
download | tor-912c11761c5b5b0a80e232bdc96788677300ca67.tar.gz tor-912c11761c5b5b0a80e232bdc96788677300ca67.zip |
prop224: Move some rendclient.c code to hs_common.c
Specifically move the pick_hsdir() function and all the HSDir request tracking
code. We plan to use all that code both for v2 and v3.
This commit only moves code.
Signed-off-by: David Goulet <dgoulet@torproject.org>
Diffstat (limited to 'src/or/hs_common.c')
-rw-r--r-- | src/or/hs_common.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/src/or/hs_common.c b/src/or/hs_common.c index 0529c0cdb0..48d5f78bbb 100644 --- a/src/or/hs_common.c +++ b/src/or/hs_common.c @@ -22,6 +22,7 @@ #include "rendcommon.h" #include "rendservice.h" #include "router.h" +#include "routerset.h" #include "shared_random.h" #include "shared_random_state.h" @@ -1320,6 +1321,229 @@ hs_get_responsible_hsdirs(const ed25519_public_key_t *blinded_pk, smartlist_free(sorted_nodes); } +/*********************** HSDir request tracking ***************************/ + +/** Return the period for which a hidden service directory cannot be queried + * for the same descriptor ID again, taking TestingTorNetwork into account. */ +static time_t +hsdir_requery_period(const or_options_t *options) +{ + tor_assert(options); + + if (options->TestingTorNetwork) { + return REND_HID_SERV_DIR_REQUERY_PERIOD_TESTING; + } else { + return REND_HID_SERV_DIR_REQUERY_PERIOD; + } +} + +/** Contains the last request times to hidden service directories for + * certain queries; each key is a string consisting of the + * concatenation of a base32-encoded HS directory identity digest and + * base32-encoded HS descriptor ID; each value is a pointer to a time_t + * holding the time of the last request for that descriptor ID to that + * HS directory. */ +static strmap_t *last_hid_serv_requests_ = NULL; + +/** Returns last_hid_serv_requests_, initializing it to a new strmap if + * necessary. */ +static strmap_t * +get_last_hid_serv_requests(void) +{ + if (!last_hid_serv_requests_) + last_hid_serv_requests_ = strmap_new(); + return last_hid_serv_requests_; +} + +#define LAST_HID_SERV_REQUEST_KEY_LEN (REND_DESC_ID_V2_LEN_BASE32 + \ + REND_DESC_ID_V2_LEN_BASE32) + +/** 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[LAST_HID_SERV_REQUEST_KEY_LEN + 1]; + time_t *last_request_ptr; + strmap_t *last_hid_serv_requests = get_last_hid_serv_requests(); + 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); + /* XXX++?? tor_assert(strlen(hsdir_desc_comb_id) == + LAST_HID_SERV_REQUEST_KEY_LEN); */ + if (set) { + time_t *oldptr; + last_request_ptr = tor_malloc_zero(sizeof(time_t)); + *last_request_ptr = now; + oldptr = strmap_set(last_hid_serv_requests, hsdir_desc_comb_id, + last_request_ptr); + tor_free(oldptr); + } 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(time_t now) +{ + strmap_iter_t *iter; + time_t cutoff = now - hsdir_requery_period(get_options()); + strmap_t *last_hid_serv_requests = get_last_hid_serv_requests(); + 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); + } + } +} + +/** Remove all requests related to the descriptor ID <b>desc_id</b> from the + * history of times of requests to hidden service directories. + * <b>desc_id</b> is an unencoded descriptor ID of size DIGEST_LEN. + * + * This is called from rend_client_note_connection_attempt_ended(), which + * must be idempotent, so any future changes to this function must leave it + * idempotent too. */ +void +purge_hid_serv_from_last_hid_serv_requests(const char *desc_id) +{ + strmap_iter_t *iter; + strmap_t *last_hid_serv_requests = get_last_hid_serv_requests(); + char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1]; + + /* Key is stored with the base32 encoded desc_id. */ + base32_encode(desc_id_base32, sizeof(desc_id_base32), desc_id, + DIGEST_LEN); + for (iter = strmap_iter_init(last_hid_serv_requests); + !strmap_iter_done(iter); ) { + const char *key; + void *val; + strmap_iter_get(iter, &key, &val); + /* XXX++?? tor_assert(strlen(key) == LAST_HID_SERV_REQUEST_KEY_LEN); */ + if (tor_memeq(key + LAST_HID_SERV_REQUEST_KEY_LEN - + REND_DESC_ID_V2_LEN_BASE32, + desc_id_base32, + REND_DESC_ID_V2_LEN_BASE32)) { + iter = strmap_iter_next_rmv(last_hid_serv_requests, iter); + tor_free(val); + } else { + iter = strmap_iter_next(last_hid_serv_requests, iter); + } + } +} + +/** Purge the history of request times to hidden service directories, + * so that future lookups of an HS descriptor will not fail because we + * accessed all of the HSDir relays responsible for the descriptor + * recently. */ +void +rend_client_purge_last_hid_serv_requests(void) +{ + /* Don't create the table if it doesn't exist yet (and it may very + * well not exist if the user hasn't accessed any HSes)... */ + strmap_t *old_last_hid_serv_requests = last_hid_serv_requests_; + /* ... and let get_last_hid_serv_requests re-create it for us if + * necessary. */ + last_hid_serv_requests_ = NULL; + + if (old_last_hid_serv_requests != NULL) { + log_info(LD_REND, "Purging client last-HS-desc-request-time table"); + strmap_free(old_last_hid_serv_requests, tor_free_); + } +} + +/***********************************************************************/ + +/** This returns a good valid hs dir that should be used for the given + * descriptor id. + * + * Return NULL on error else the hsdir node pointer. */ +routerstatus_t * +pick_hsdir(const char *desc_id, const char *desc_id_base32) +{ + smartlist_t *responsible_dirs = smartlist_new(); + smartlist_t *usable_responsible_dirs = smartlist_new(); + const or_options_t *options = get_options(); + routerstatus_t *hs_dir; + time_t now = time(NULL); + int excluded_some; + + tor_assert(desc_id); + tor_assert(desc_id_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. */ + hid_serv_get_responsible_directories(responsible_dirs, desc_id); + + /* Clean request history first. */ + directory_clean_last_hid_serv_requests(now); + + /* Only select those hidden service directories to which we did not send a + * request recently and for which we have a router descriptor here. */ + SMARTLIST_FOREACH_BEGIN(responsible_dirs, routerstatus_t *, dir) { + time_t last = lookup_last_hid_serv_request(dir, desc_id_base32, + 0, 0); + const node_t *node = node_get_by_id(dir->identity_digest); + if (last + hsdir_requery_period(options) >= now || + !node || !node_has_descriptor(node)) { + SMARTLIST_DEL_CURRENT(responsible_dirs, dir); + continue; + } + if (!routerset_contains_node(options->ExcludeNodes, node)) { + smartlist_add(usable_responsible_dirs, dir); + } + } SMARTLIST_FOREACH_END(dir); + + excluded_some = + smartlist_len(usable_responsible_dirs) < smartlist_len(responsible_dirs); + + hs_dir = smartlist_choose(usable_responsible_dirs); + if (!hs_dir && !options->StrictNodes) { + hs_dir = smartlist_choose(responsible_dirs); + } + + smartlist_free(responsible_dirs); + smartlist_free(usable_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."); + if (options->StrictNodes && excluded_some) { + log_warn(LD_REND, "Could not pick a hidden service directory for the " + "requested hidden service: they are all either down or " + "excluded, and StrictNodes is set."); + } + } else { + /* 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); + } + + return hs_dir; +} + +/***********************************************************************/ + /* Initialize the entire HS subsytem. This is called in tor_init() before any * torrc options are loaded. Only for >= v3. */ void |