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- /* Copyright (c) 2017, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /**
- * \file consdiffmsr.c
- *
- * \brief consensus diff manager functions
- *
- * This module is run by directory authorities and caches in order
- * to remember a number of past consensus documents, and to generate
- * and serve the diffs from those documents to the latest consensus.
- */
- #define CONSDIFFMGR_PRIVATE
- #include "or.h"
- #include "conscache.h"
- #include "consdiff.h"
- #include "consdiffmgr.h"
- #include "cpuworker.h"
- #include "networkstatus.h"
- #include "workqueue.h"
- /* XXXX support compression */
- /**
- * Labels to apply to items in the conscache object.
- *
- * @{
- */
- /* One of DOCTYPE_CONSENSUS or DOCTYPE_CONSENSUS_DIFF */
- #define LABEL_DOCTYPE "document-type"
- /* The valid-after time for a consensus (or for the target consensus of a
- * diff), encoded as ISO UTC. */
- #define LABEL_VALID_AFTER "consensus-valid-after"
- /* A hex encoded SHA3 digest of the object after decompression. */
- #define LABEL_SHA3_DIGEST "sha3-digest"
- /* The flavor of the consensus or consensuses diff */
- #define LABEL_FLAVOR "consensus-flavor"
- /* Diff only: the SHA3 digest of the source consensus. */
- #define LABEL_FROM_SHA3_DIGEST "from-sha3-digest"
- /* Diff only: the SHA3 digest of the target consensus. */
- #define LABEL_TARGET_SHA3_DIGEST "target-sha3-digest"
- /* Diff only: the valid-after date of the source consensus. */
- #define LABEL_FROM_VALID_AFTER "from-valid-after"
- /** @} */
- #define DOCTYPE_CONSENSUS "consensus"
- #define DOCTYPE_CONSENSUS_DIFF "consensus-diff"
- /**
- * Underlying directory that stores consensuses and consensus diffs. Don't
- * use this directly: use cdm_cache_get() instead.
- */
- static consensus_cache_t *cons_diff_cache = NULL;
- /**
- * If true, we have learned at least one new consensus since the
- * consensus cache was last up-to-date.
- */
- static int cdm_cache_dirty = 0;
- /**
- * If true, we have scanned the cache to update our hashtable of diffs.
- */
- static int cdm_cache_loaded = 0;
- /**
- * Possible status values for cdm_diff_t.cdm_diff_status
- **/
- typedef enum cdm_diff_status_t {
- CDM_DIFF_PRESENT=1,
- CDM_DIFF_IN_PROGRESS=2,
- CDM_DIFF_ERROR=3,
- } cdm_diff_status_t;
- /** Hashtable node used to remember the current status of the diff
- * from a given sha3 digest to the current consensus. */
- typedef struct cdm_diff_t {
- HT_ENTRY(cdm_diff_t) node;
- /** Consensus flavor for this diff (part of ht key) */
- consensus_flavor_t flavor;
- /** SHA3-256 digest of the consensus that this diff is _from_. (part of the
- * ht key) */
- uint8_t from_sha3[DIGEST256_LEN];
- /** One of the CDM_DIFF_* values, depending on whether this diff
- * is available, in progress, or impossible to compute. */
- cdm_diff_status_t cdm_diff_status;
- /** SHA3-256 digest of the consensus that this diff is _to. */
- uint8_t target_sha3[DIGEST256_LEN];
- /** Handle to the cache entry for this diff, if any. We use a handle here
- * to avoid thinking too hard about cache entry lifetime issues. */
- consensus_cache_entry_handle_t *entry;
- } cdm_diff_t;
- /** Hashtable mapping flavor and source consensus digest to status. */
- static HT_HEAD(cdm_diff_ht, cdm_diff_t) cdm_diff_ht = HT_INITIALIZER();
- /**
- * Configuration for this module
- */
- static consdiff_cfg_t consdiff_cfg = {
- /* .cache_max_age_hours = */ 24 * 90,
- /* .cache_max_num = */ 1440
- };
- static int consensus_diff_queue_diff_work(consensus_cache_entry_t *diff_from,
- consensus_cache_entry_t *diff_to);
- static void consdiffmgr_set_cache_flags(void);
- /* =====
- * Hashtable setup
- * ===== */
- /** Helper: hash the key of a cdm_diff_t. */
- static unsigned
- cdm_diff_hash(const cdm_diff_t *diff)
- {
- uint8_t tmp[DIGEST256_LEN + 1];
- memcpy(tmp, diff->from_sha3, DIGEST256_LEN);
- tmp[DIGEST256_LEN] = (uint8_t) diff->flavor;
- return (unsigned) siphash24g(tmp, sizeof(tmp));
- }
- /** Helper: compare two cdm_diff_t objects for key equality */
- static int
- cdm_diff_eq(const cdm_diff_t *diff1, const cdm_diff_t *diff2)
- {
- return fast_memeq(diff1->from_sha3, diff2->from_sha3, DIGEST256_LEN) &&
- diff1->flavor == diff2->flavor;
- }
- HT_PROTOTYPE(cdm_diff_ht, cdm_diff_t, node, cdm_diff_hash, cdm_diff_eq)
- HT_GENERATE2(cdm_diff_ht, cdm_diff_t, node, cdm_diff_hash, cdm_diff_eq,
- 0.6, tor_reallocarray, tor_free_)
- /** Release all storage held in <b>diff</b>. */
- static void
- cdm_diff_free(cdm_diff_t *diff)
- {
- if (!diff)
- return;
- consensus_cache_entry_handle_free(diff->entry);
- tor_free(diff);
- }
- /** Create and return a new cdm_diff_t with the given values. Does not
- * add it to the hashtable. */
- static cdm_diff_t *
- cdm_diff_new(consensus_flavor_t flav,
- const uint8_t *from_sha3,
- const uint8_t *target_sha3)
- {
- cdm_diff_t *ent;
- ent = tor_malloc_zero(sizeof(cdm_diff_t));
- ent->flavor = flav;
- memcpy(ent->from_sha3, from_sha3, DIGEST256_LEN);
- memcpy(ent->target_sha3, target_sha3, DIGEST256_LEN);
- return ent;
- }
- /**
- * Examine the diff hashtable to see whether we know anything about computing
- * a diff of type <b>flav</b> between consensuses with the two provided
- * SHA3-256 digests. If a computation is in progress, or if the computation
- * has already been tried and failed, return 1. Otherwise, note the
- * computation as "in progress" so that we don't reattempt it later, and
- * return 0.
- */
- static int
- cdm_diff_ht_check_and_note_pending(consensus_flavor_t flav,
- const uint8_t *from_sha3,
- const uint8_t *target_sha3)
- {
- struct cdm_diff_t search, *ent;
- memset(&search, 0, sizeof(cdm_diff_t));
- search.flavor = flav;
- memcpy(search.from_sha3, from_sha3, DIGEST256_LEN);
- ent = HT_FIND(cdm_diff_ht, &cdm_diff_ht, &search);
- if (ent) {
- tor_assert_nonfatal(ent->cdm_diff_status != CDM_DIFF_PRESENT);
- return 1;
- }
- ent = cdm_diff_new(flav, from_sha3, target_sha3);
- ent->cdm_diff_status = CDM_DIFF_IN_PROGRESS;
- HT_INSERT(cdm_diff_ht, &cdm_diff_ht, ent);
- return 0;
- }
- /**
- * Update the status of the diff of type <b>flav</b> between consensuses with
- * the two provided SHA3-256 digests, so that its status becomes
- * <b>status</b>, and its value becomes the <b>handle</b>. If <b>handle</b>
- * is NULL, then the old handle (if any) is freed, and replaced with NULL.
- */
- static void
- cdm_diff_ht_set_status(consensus_flavor_t flav,
- const uint8_t *from_sha3,
- const uint8_t *to_sha3,
- int status,
- consensus_cache_entry_handle_t *handle)
- {
- struct cdm_diff_t search, *ent;
- memset(&search, 0, sizeof(cdm_diff_t));
- search.flavor = flav;
- memcpy(search.from_sha3, from_sha3, DIGEST256_LEN);
- ent = HT_FIND(cdm_diff_ht, &cdm_diff_ht, &search);
- if (!ent) {
- ent = cdm_diff_new(flav, from_sha3, to_sha3);
- ent->cdm_diff_status = CDM_DIFF_IN_PROGRESS;
- HT_INSERT(cdm_diff_ht, &cdm_diff_ht, ent);
- } else if (fast_memneq(ent->target_sha3, to_sha3, DIGEST256_LEN)) {
- // This can happen under certain really pathological conditions
- // if we decide we don't care about a diff before it is actually
- // done computing.
- return;
- }
- tor_assert_nonfatal(ent->cdm_diff_status == CDM_DIFF_IN_PROGRESS);
- ent->cdm_diff_status = status;
- consensus_cache_entry_handle_free(ent->entry);
- ent->entry = handle;
- }
- /**
- * Helper: Remove from the hash table every present (actually computed) diff
- * of type <b>flav</b> whose target digest does not match
- * <b>unless_target_sha3_matches</b>.
- *
- * This function is used for the hash table to throw away references to diffs
- * that do not lead to the most given consensus of a given flavor.
- */
- static void
- cdm_diff_ht_purge(consensus_flavor_t flav,
- const uint8_t *unless_target_sha3_matches)
- {
- cdm_diff_t **diff, **next;
- for (diff = HT_START(cdm_diff_ht, &cdm_diff_ht); diff; diff = next) {
- cdm_diff_t *this = *diff;
- if ((*diff)->cdm_diff_status == CDM_DIFF_PRESENT &&
- flav == (*diff)->flavor) {
- if (consensus_cache_entry_handle_get((*diff)->entry) == NULL) {
- /* the underlying entry has gone away; drop this. */
- next = HT_NEXT_RMV(cdm_diff_ht, &cdm_diff_ht, diff);
- cdm_diff_free(this);
- continue;
- }
- if (unless_target_sha3_matches &&
- fast_memneq(unless_target_sha3_matches, (*diff)->target_sha3,
- DIGEST256_LEN)) {
- /* target hash doesn't match; drop this. */
- next = HT_NEXT_RMV(cdm_diff_ht, &cdm_diff_ht, diff);
- cdm_diff_free(this);
- continue;
- }
- }
- next = HT_NEXT(cdm_diff_ht, &cdm_diff_ht, diff);
- }
- }
- /**
- * Helper: initialize <b>cons_diff_cache</b>.
- */
- static void
- cdm_cache_init(void)
- {
- unsigned n_entries = consdiff_cfg.cache_max_num * 2;
- tor_assert(cons_diff_cache == NULL);
- cons_diff_cache = consensus_cache_open("diff-cache", n_entries);
- if (cons_diff_cache == NULL) {
- // LCOV_EXCL_START
- log_err(LD_FS, "Error: Couldn't open storage for consensus diffs.");
- tor_assert_unreached();
- // LCOV_EXCL_STOP
- } else {
- consdiffmgr_set_cache_flags();
- }
- cdm_cache_dirty = 1;
- cdm_cache_loaded = 0;
- }
- /**
- * Helper: return the consensus_cache_t * that backs this manager,
- * initializing it if needed.
- */
- STATIC consensus_cache_t *
- cdm_cache_get(void)
- {
- if (PREDICT_UNLIKELY(cons_diff_cache == NULL)) {
- cdm_cache_init();
- }
- return cons_diff_cache;
- }
- /**
- * Helper: given a list of labels, prepend the hex-encoded SHA3 digest
- * of the <b>bodylen</b>-byte object at <b>body</b> to those labels,
- * with LABEL_SHA3_DIGEST as its label.
- */
- static void
- cdm_labels_prepend_sha3(config_line_t **labels,
- const uint8_t *body,
- size_t bodylen)
- {
- uint8_t sha3_digest[DIGEST256_LEN];
- char hexdigest[HEX_DIGEST256_LEN+1];
- crypto_digest256((char *)sha3_digest,
- (const char *)body, bodylen, DIGEST_SHA3_256);
- base16_encode(hexdigest, sizeof(hexdigest),
- (const char *)sha3_digest, sizeof(sha3_digest));
- config_line_prepend(labels, LABEL_SHA3_DIGEST, hexdigest);
- }
- /** Helper: if there is a sha3-256 hex-encoded digest in <b>ent</b> with the
- * given label, set <b>digest_out</b> to that value (decoded), and return 0.
- *
- * Return -1 if there is no such label, and -2 if it is badly formatted. */
- STATIC int
- cdm_entry_get_sha3_value(uint8_t *digest_out,
- consensus_cache_entry_t *ent,
- const char *label)
- {
- if (ent == NULL)
- return -1;
- const char *hex = consensus_cache_entry_get_value(ent, label);
- if (hex == NULL)
- return -1;
- int n = base16_decode((char*)digest_out, DIGEST256_LEN, hex, strlen(hex));
- if (n != DIGEST256_LEN)
- return -2;
- else
- return 0;
- }
- /**
- * Helper: look for a consensus with the given <b>flavor</b> and
- * <b>valid_after</b> time in the cache. Return that consensus if it's
- * present, or NULL if it's missing.
- */
- STATIC consensus_cache_entry_t *
- cdm_cache_lookup_consensus(consensus_flavor_t flavor, time_t valid_after)
- {
- char formatted_time[ISO_TIME_LEN+1];
- format_iso_time_nospace(formatted_time, valid_after);
- const char *flavname = networkstatus_get_flavor_name(flavor);
- /* We'll filter by valid-after time first, since that should
- * match the fewest documents. */
- /* We could add an extra hashtable here, but since we only do this scan
- * when adding a new consensus, it probably doesn't matter much. */
- smartlist_t *matches = smartlist_new();
- consensus_cache_find_all(matches, cdm_cache_get(),
- LABEL_VALID_AFTER, formatted_time);
- consensus_cache_filter_list(matches, LABEL_FLAVOR, flavname);
- consensus_cache_filter_list(matches, LABEL_DOCTYPE, DOCTYPE_CONSENSUS);
- consensus_cache_entry_t *result = NULL;
- if (smartlist_len(matches) > 1) {
- log_warn(LD_BUG, "How odd; there appear to be two matching consensuses "
- "with flavor %s published at %s.",
- flavname, formatted_time);
- }
- if (smartlist_len(matches)) {
- result = smartlist_get(matches, 0);
- }
- smartlist_free(matches);
- return result;
- }
- /**
- * Given a string containing a networkstatus consensus, and the results of
- * having parsed that consensus, add that consensus to the cache if it is not
- * already present and not too old. Create new consensus diffs from or to
- * that consensus as appropriate.
- *
- * Return 0 on success and -1 on failure.
- */
- int
- consdiffmgr_add_consensus(const char *consensus,
- const networkstatus_t *as_parsed)
- {
- if (BUG(consensus == NULL) || BUG(as_parsed == NULL))
- return -1; // LCOV_EXCL_LINE
- if (BUG(as_parsed->type != NS_TYPE_CONSENSUS))
- return -1; // LCOV_EXCL_LINE
- const consensus_flavor_t flavor = as_parsed->flavor;
- const time_t valid_after = as_parsed->valid_after;
- if (valid_after < approx_time() - 3600 * consdiff_cfg.cache_max_age_hours) {
- log_info(LD_DIRSERV, "We don't care about this consensus document; it's "
- "too old.");
- return -1;
- }
- /* Do we already have this one? */
- consensus_cache_entry_t *entry =
- cdm_cache_lookup_consensus(flavor, valid_after);
- if (entry) {
- log_info(LD_DIRSERV, "We already have a copy of that consensus");
- return -1;
- }
- /* We don't have it. Add it to the cache. */
- {
- size_t bodylen = strlen(consensus);
- config_line_t *labels = NULL;
- char formatted_time[ISO_TIME_LEN+1];
- format_iso_time_nospace(formatted_time, valid_after);
- const char *flavname = networkstatus_get_flavor_name(flavor);
- cdm_labels_prepend_sha3(&labels, (const uint8_t *)consensus, bodylen);
- config_line_prepend(&labels, LABEL_FLAVOR, flavname);
- config_line_prepend(&labels, LABEL_VALID_AFTER, formatted_time);
- config_line_prepend(&labels, LABEL_DOCTYPE, DOCTYPE_CONSENSUS);
- entry = consensus_cache_add(cdm_cache_get(),
- labels,
- (const uint8_t *)consensus,
- bodylen);
- config_free_lines(labels);
- }
- if (entry) {
- consensus_cache_entry_mark_for_aggressive_release(entry);
- consensus_cache_entry_decref(entry);
- }
- cdm_cache_dirty = 1;
- return entry ? 0 : -1;
- }
- /**
- * Helper: used to sort two smartlists of consensus_cache_entry_t by their
- * LABEL_VALID_AFTER labels.
- */
- static int
- compare_by_valid_after_(const void **a, const void **b)
- {
- const consensus_cache_entry_t *e1 = *a;
- const consensus_cache_entry_t *e2 = *b;
- /* We're in luck here: sorting UTC iso-encoded values lexically will work
- * fine (until 9999). */
- return strcmp_opt(consensus_cache_entry_get_value(e1, LABEL_VALID_AFTER),
- consensus_cache_entry_get_value(e2, LABEL_VALID_AFTER));
- }
- /**
- * Helper: Sort <b>lst</b> by LABEL_VALID_AFTER and return the most recent
- * entry.
- */
- static consensus_cache_entry_t *
- sort_and_find_most_recent(smartlist_t *lst)
- {
- smartlist_sort(lst, compare_by_valid_after_);
- if (smartlist_len(lst)) {
- return smartlist_get(lst, smartlist_len(lst) - 1);
- } else {
- return NULL;
- }
- }
- /**
- * Look up consensus_cache_entry_t for the consensus of type <b>flavor</b>,
- * from the source consensus with the specified digest (which must be SHA3).
- *
- * If the diff is present, store it into *<b>entry_out</b> and return
- * CONSDIFF_AVAILABLE. Otherwise return CONSDIFF_NOT_FOUND or
- * CONSDIFF_IN_PROGRESS.
- */
- consdiff_status_t
- consdiffmgr_find_diff_from(consensus_cache_entry_t **entry_out,
- consensus_flavor_t flavor,
- int digest_type,
- const uint8_t *digest,
- size_t digestlen)
- {
- if (BUG(digest_type != DIGEST_SHA3_256) ||
- BUG(digestlen != DIGEST256_LEN)) {
- return CONSDIFF_NOT_FOUND; // LCOV_EXCL_LINE
- }
- // Try to look up the entry in the hashtable.
- cdm_diff_t search, *ent;
- memset(&search, 0, sizeof(search));
- search.flavor = flavor;
- memcpy(search.from_sha3, digest, DIGEST256_LEN);
- ent = HT_FIND(cdm_diff_ht, &cdm_diff_ht, &search);
- if (ent == NULL ||
- ent->cdm_diff_status == CDM_DIFF_ERROR) {
- return CONSDIFF_NOT_FOUND;
- } else if (ent->cdm_diff_status == CDM_DIFF_IN_PROGRESS) {
- return CONSDIFF_IN_PROGRESS;
- } else if (BUG(ent->cdm_diff_status != CDM_DIFF_PRESENT)) {
- return CONSDIFF_IN_PROGRESS;
- }
- *entry_out = consensus_cache_entry_handle_get(ent->entry);
- return (*entry_out) ? CONSDIFF_AVAILABLE : CONSDIFF_NOT_FOUND;
- #if 0
- // XXXX Remove this. I'm keeping it around for now in case we need to
- // XXXX debug issues in the hashtable.
- char hex[HEX_DIGEST256_LEN+1];
- base16_encode(hex, sizeof(hex), (const char *)digest, digestlen);
- const char *flavname = networkstatus_get_flavor_name(flavor);
- smartlist_t *matches = smartlist_new();
- consensus_cache_find_all(matches, cdm_cache_get(),
- LABEL_FROM_SHA3_DIGEST, hex);
- consensus_cache_filter_list(matches, LABEL_FLAVOR, flavname);
- consensus_cache_filter_list(matches, LABEL_DOCTYPE, DOCTYPE_CONSENSUS_DIFF);
- *entry_out = sort_and_find_most_recent(matches);
- consdiff_status_t result =
- (*entry_out) ? CONSDIFF_AVAILABLE : CONSDIFF_NOT_FOUND;
- smartlist_free(matches);
- return result;
- #endif
- }
- /**
- * Perform periodic cleanup tasks on the consensus diff cache. Return
- * the number of objects marked for deletion.
- */
- int
- consdiffmgr_cleanup(void)
- {
- smartlist_t *objects = smartlist_new();
- smartlist_t *consensuses = smartlist_new();
- smartlist_t *diffs = smartlist_new();
- int n_to_delete = 0;
- log_debug(LD_DIRSERV, "Looking for consdiffmgr entries to remove");
- // 1. Delete any consensus or diff or anything whose valid_after is too old.
- const time_t valid_after_cutoff =
- approx_time() - 3600 * consdiff_cfg.cache_max_age_hours;
- consensus_cache_find_all(objects, cdm_cache_get(),
- NULL, NULL);
- SMARTLIST_FOREACH_BEGIN(objects, consensus_cache_entry_t *, ent) {
- const char *lv_valid_after =
- consensus_cache_entry_get_value(ent, LABEL_VALID_AFTER);
- if (! lv_valid_after) {
- log_debug(LD_DIRSERV, "Ignoring entry because it had no %s label",
- LABEL_VALID_AFTER);
- continue;
- }
- time_t valid_after = 0;
- if (parse_iso_time_nospace(lv_valid_after, &valid_after) < 0) {
- log_debug(LD_DIRSERV, "Ignoring entry because its %s value (%s) was "
- "unparseable", LABEL_VALID_AFTER, escaped(lv_valid_after));
- continue;
- }
- if (valid_after < valid_after_cutoff) {
- log_debug(LD_DIRSERV, "Deleting entry because its %s value (%s) was "
- "too old", LABEL_VALID_AFTER, lv_valid_after);
- consensus_cache_entry_mark_for_removal(ent);
- ++n_to_delete;
- }
- } SMARTLIST_FOREACH_END(ent);
- // 2. Delete all diffs that lead to a consensus whose valid-after is not the
- // latest.
- for (int flav = 0; flav < N_CONSENSUS_FLAVORS; ++flav) {
- const char *flavname = networkstatus_get_flavor_name(flav);
- /* Determine the most recent consensus of this flavor */
- consensus_cache_find_all(consensuses, cdm_cache_get(),
- LABEL_DOCTYPE, DOCTYPE_CONSENSUS);
- consensus_cache_filter_list(consensuses, LABEL_FLAVOR, flavname);
- consensus_cache_entry_t *most_recent =
- sort_and_find_most_recent(consensuses);
- if (most_recent == NULL)
- continue;
- const char *most_recent_sha3 =
- consensus_cache_entry_get_value(most_recent, LABEL_SHA3_DIGEST);
- if (BUG(most_recent_sha3 == NULL))
- continue; // LCOV_EXCL_LINE
- /* consider all such-flavored diffs, and look to see if they match. */
- consensus_cache_find_all(diffs, cdm_cache_get(),
- LABEL_DOCTYPE, DOCTYPE_CONSENSUS_DIFF);
- consensus_cache_filter_list(diffs, LABEL_FLAVOR, flavname);
- SMARTLIST_FOREACH_BEGIN(diffs, consensus_cache_entry_t *, diff) {
- const char *this_diff_target_sha3 =
- consensus_cache_entry_get_value(diff, LABEL_TARGET_SHA3_DIGEST);
- if (!this_diff_target_sha3)
- continue;
- if (strcmp(this_diff_target_sha3, most_recent_sha3)) {
- consensus_cache_entry_mark_for_removal(diff);
- ++n_to_delete;
- }
- } SMARTLIST_FOREACH_END(diff);
- smartlist_clear(consensuses);
- smartlist_clear(diffs);
- }
- smartlist_free(objects);
- smartlist_free(consensuses);
- smartlist_free(diffs);
- // Actually remove files, if they're not used.
- consensus_cache_delete_pending(cdm_cache_get());
- return n_to_delete;
- }
- /**
- * Initialize the consensus diff manager and its cache, and configure
- * its parameters based on the latest torrc and networkstatus parameters.
- */
- void
- consdiffmgr_configure(const consdiff_cfg_t *cfg)
- {
- memcpy(&consdiff_cfg, cfg, sizeof(consdiff_cfg));
- (void) cdm_cache_get();
- }
- /**
- * Scan the consensus diff manager's cache for any grossly malformed entries,
- * and mark them as deletable. Return 0 if no problems were found; 1
- * if problems were found and fixed.
- */
- int
- consdiffmgr_validate(void)
- {
- /* Right now, we only check for entries that have bad sha3 values */
- int problems = 0;
- smartlist_t *objects = smartlist_new();
- consensus_cache_find_all(objects, cdm_cache_get(),
- NULL, NULL);
- SMARTLIST_FOREACH_BEGIN(objects, consensus_cache_entry_t *, obj) {
- uint8_t sha3_expected[DIGEST256_LEN];
- uint8_t sha3_received[DIGEST256_LEN];
- int r = cdm_entry_get_sha3_value(sha3_expected, obj, LABEL_SHA3_DIGEST);
- if (r == -1) {
- /* digest isn't there; that's allowed */
- continue;
- } else if (r == -2) {
- /* digest is malformed; that's not allowed */
- problems = 1;
- consensus_cache_entry_mark_for_removal(obj);
- continue;
- }
- const uint8_t *body;
- size_t bodylen;
- consensus_cache_entry_incref(obj);
- r = consensus_cache_entry_get_body(obj, &body, &bodylen);
- if (r == 0) {
- crypto_digest256((char *)sha3_received, (const char *)body, bodylen,
- DIGEST_SHA3_256);
- }
- consensus_cache_entry_decref(obj);
- if (r < 0)
- continue;
- if (fast_memneq(sha3_received, sha3_expected, DIGEST256_LEN)) {
- problems = 1;
- consensus_cache_entry_mark_for_removal(obj);
- continue;
- }
- } SMARTLIST_FOREACH_END(obj);
- smartlist_free(objects);
- return problems;
- }
- /**
- * Helper: build new diffs of <b>flavor</b> as needed
- */
- static void
- consdiffmgr_rescan_flavor_(consensus_flavor_t flavor)
- {
- smartlist_t *matches = NULL;
- smartlist_t *diffs = NULL;
- smartlist_t *compute_diffs_from = NULL;
- strmap_t *have_diff_from = NULL;
- // look for the most recent consensus, and for all previous in-range
- // consensuses. Do they all have diffs to it?
- const char *flavname = networkstatus_get_flavor_name(flavor);
- // 1. find the most recent consensus, and the ones that we might want
- // to diff to it.
- matches = smartlist_new();
- consensus_cache_find_all(matches, cdm_cache_get(),
- LABEL_FLAVOR, flavname);
- consensus_cache_filter_list(matches, LABEL_DOCTYPE, DOCTYPE_CONSENSUS);
- consensus_cache_entry_t *most_recent = sort_and_find_most_recent(matches);
- if (!most_recent) {
- log_info(LD_DIRSERV, "No 'most recent' %s consensus found; "
- "not making diffs", flavname);
- goto done;
- }
- tor_assert(smartlist_len(matches));
- smartlist_del(matches, smartlist_len(matches) - 1);
- const char *most_recent_valid_after =
- consensus_cache_entry_get_value(most_recent, LABEL_VALID_AFTER);
- if (BUG(most_recent_valid_after == NULL))
- goto done; //LCOV_EXCL_LINE
- uint8_t most_recent_sha3[DIGEST256_LEN];
- if (BUG(cdm_entry_get_sha3_value(most_recent_sha3, most_recent,
- LABEL_SHA3_DIGEST) < 0))
- goto done; //LCOV_EXCL_LINE
- // 2. Find all the relevant diffs _to_ this consensus. These are ones
- // that we don't need to compute.
- diffs = smartlist_new();
- consensus_cache_find_all(diffs, cdm_cache_get(),
- LABEL_VALID_AFTER, most_recent_valid_after);
- consensus_cache_filter_list(diffs, LABEL_DOCTYPE, DOCTYPE_CONSENSUS_DIFF);
- consensus_cache_filter_list(diffs, LABEL_FLAVOR, flavname);
- have_diff_from = strmap_new();
- SMARTLIST_FOREACH_BEGIN(diffs, consensus_cache_entry_t *, diff) {
- const char *va = consensus_cache_entry_get_value(diff,
- LABEL_FROM_VALID_AFTER);
- if (BUG(va == NULL))
- continue; // LCOV_EXCL_LINE
- strmap_set(have_diff_from, va, diff);
- } SMARTLIST_FOREACH_END(diff);
- // 3. See which consensuses in 'matches' don't have diffs yet.
- smartlist_reverse(matches); // from newest to oldest.
- compute_diffs_from = smartlist_new();
- SMARTLIST_FOREACH_BEGIN(matches, consensus_cache_entry_t *, ent) {
- const char *va = consensus_cache_entry_get_value(ent, LABEL_VALID_AFTER);
- if (BUG(va == NULL))
- continue; // LCOV_EXCL_LINE
- if (strmap_get(have_diff_from, va) != NULL)
- continue; /* we already have this one. */
- smartlist_add(compute_diffs_from, ent);
- } SMARTLIST_FOREACH_END(ent);
- log_info(LD_DIRSERV,
- "The most recent %s consensus is valid-after %s. We have diffs to "
- "this consensus for %d/%d older %s consensuses. Generating diffs "
- "for the other %d.",
- flavname,
- most_recent_valid_after,
- smartlist_len(matches) - smartlist_len(compute_diffs_from),
- smartlist_len(matches),
- flavname,
- smartlist_len(compute_diffs_from));
- // 4. Update the hashtable; remove entries in this flavor to other
- // target consensuses.
- cdm_diff_ht_purge(flavor, most_recent_sha3);
- // 5. Actually launch the requests.
- SMARTLIST_FOREACH_BEGIN(compute_diffs_from, consensus_cache_entry_t *, c) {
- if (BUG(c == most_recent))
- continue; // LCOV_EXCL_LINE
- uint8_t this_sha3[DIGEST256_LEN];
- if (BUG(cdm_entry_get_sha3_value(this_sha3, c, LABEL_SHA3_DIGEST)<0))
- continue; // LCOV_EXCL_LINE
- if (cdm_diff_ht_check_and_note_pending(flavor,
- this_sha3, most_recent_sha3)) {
- // This is already pending, or we encountered an error.
- continue;
- }
- consensus_diff_queue_diff_work(c, most_recent);
- } SMARTLIST_FOREACH_END(c);
- done:
- smartlist_free(matches);
- smartlist_free(diffs);
- smartlist_free(compute_diffs_from);
- strmap_free(have_diff_from, NULL);
- }
- /**
- * Scan the cache for diffs, and add them to the hashtable.
- */
- static void
- consdiffmgr_diffs_load(void)
- {
- smartlist_t *diffs = smartlist_new();
- consensus_cache_find_all(diffs, cdm_cache_get(),
- LABEL_DOCTYPE, DOCTYPE_CONSENSUS_DIFF);
- SMARTLIST_FOREACH_BEGIN(diffs, consensus_cache_entry_t *, diff) {
- const char *lv_flavor =
- consensus_cache_entry_get_value(diff, LABEL_FLAVOR);
- if (!lv_flavor)
- continue;
- int flavor = networkstatus_parse_flavor_name(lv_flavor);
- if (flavor < 0)
- continue;
- uint8_t from_sha3[DIGEST256_LEN];
- uint8_t to_sha3[DIGEST256_LEN];
- if (cdm_entry_get_sha3_value(from_sha3, diff, LABEL_FROM_SHA3_DIGEST)<0)
- continue;
- if (cdm_entry_get_sha3_value(to_sha3, diff, LABEL_TARGET_SHA3_DIGEST)<0)
- continue;
- cdm_diff_ht_set_status(flavor, from_sha3, to_sha3,
- CDM_DIFF_PRESENT,
- consensus_cache_entry_handle_new(diff));
- } SMARTLIST_FOREACH_END(diff);
- smartlist_free(diffs);
- }
- /**
- * Build new diffs as needed.
- */
- void
- consdiffmgr_rescan(void)
- {
- if (cdm_cache_dirty == 0)
- return;
- // Clean up here to make room for new diffs, and to ensure that older
- // consensuses do not have any entries.
- consdiffmgr_cleanup();
- if (cdm_cache_loaded == 0) {
- consdiffmgr_diffs_load();
- cdm_cache_loaded = 1;
- }
- for (int flav = 0; flav < N_CONSENSUS_FLAVORS; ++flav) {
- consdiffmgr_rescan_flavor_((consensus_flavor_t) flav);
- }
- cdm_cache_dirty = 0;
- }
- /**
- * Set consensus cache flags on the objects in this consdiffmgr.
- */
- static void
- consdiffmgr_set_cache_flags(void)
- {
- /* Right now, we just mark the consensus objects for aggressive release,
- * so that they get mmapped for as little time as possible. */
- smartlist_t *objects = smartlist_new();
- consensus_cache_find_all(objects, cdm_cache_get(), LABEL_DOCTYPE,
- DOCTYPE_CONSENSUS);
- SMARTLIST_FOREACH_BEGIN(objects, consensus_cache_entry_t *, ent) {
- consensus_cache_entry_mark_for_aggressive_release(ent);
- } SMARTLIST_FOREACH_END(ent);
- smartlist_free(objects);
- }
- /**
- * Called before shutdown: drop all storage held by the consdiffmgr.c module.
- */
- void
- consdiffmgr_free_all(void)
- {
- cdm_diff_t **diff, **next;
- for (diff = HT_START(cdm_diff_ht, &cdm_diff_ht); diff; diff = next) {
- cdm_diff_t *this = *diff;
- next = HT_NEXT_RMV(cdm_diff_ht, &cdm_diff_ht, diff);
- cdm_diff_free(this);
- }
- consensus_cache_free(cons_diff_cache);
- cons_diff_cache = NULL;
- }
- /* =====
- Thread workers
- =====*/
- /**
- * An object passed to a worker thread that will try to produce a consensus
- * diff.
- */
- typedef struct consensus_diff_worker_job_t {
- /**
- * Input: The consensus to compute the diff from. Holds a reference to the
- * cache entry, which must not be released until the job is passed back to
- * the main thread. The body must be mapped into memory in the main thread.
- */
- consensus_cache_entry_t *diff_from;
- /**
- * Input: The consensus to compute the diff to. Holds a reference to the
- * cache entry, which must not be released until the job is passed back to
- * the main thread. The body must be mapped into memory in the main thread.
- */
- consensus_cache_entry_t *diff_to;
- /**
- * Output: Labels to store in the cache associated with this diff.
- */
- config_line_t *labels_out;
- /**
- * Output: Body of the diff
- */
- uint8_t *body_out;
- /**
- * Output: length of body_out
- */
- size_t bodylen_out;
- } consensus_diff_worker_job_t;
- /**
- * Worker function. This function runs inside a worker thread and receives
- * a consensus_diff_worker_job_t as its input.
- */
- static workqueue_reply_t
- consensus_diff_worker_threadfn(void *state_, void *work_)
- {
- (void)state_;
- consensus_diff_worker_job_t *job = work_;
- const uint8_t *diff_from, *diff_to;
- size_t len_from, len_to;
- int r;
- /* We need to have the body already mapped into RAM here.
- */
- r = consensus_cache_entry_get_body(job->diff_from, &diff_from, &len_from);
- if (BUG(r < 0))
- return WQ_RPL_REPLY; // LCOV_EXCL_LINE
- r = consensus_cache_entry_get_body(job->diff_to, &diff_to, &len_to);
- if (BUG(r < 0))
- return WQ_RPL_REPLY; // LCOV_EXCL_LINE
- const char *lv_to_valid_after =
- consensus_cache_entry_get_value(job->diff_to, LABEL_VALID_AFTER);
- const char *lv_from_valid_after =
- consensus_cache_entry_get_value(job->diff_from, LABEL_VALID_AFTER);
- const char *lv_from_digest =
- consensus_cache_entry_get_value(job->diff_from, LABEL_SHA3_DIGEST);
- const char *lv_from_flavor =
- consensus_cache_entry_get_value(job->diff_from, LABEL_FLAVOR);
- const char *lv_to_flavor =
- consensus_cache_entry_get_value(job->diff_to, LABEL_FLAVOR);
- const char *lv_to_digest =
- consensus_cache_entry_get_value(job->diff_to, LABEL_SHA3_DIGEST);
- /* All these values are mandatory on the input */
- if (BUG(!lv_to_valid_after) ||
- BUG(!lv_from_valid_after) ||
- BUG(!lv_from_digest) ||
- BUG(!lv_from_flavor) ||
- BUG(!lv_to_flavor)) {
- return WQ_RPL_REPLY; // LCOV_EXCL_LINE
- }
- /* The flavors need to match */
- if (BUG(strcmp(lv_from_flavor, lv_to_flavor))) {
- return WQ_RPL_REPLY; // LCOV_EXCL_LINE
- }
- char *consensus_diff;
- {
- // XXXX the input might not be nul-terminated. And also we wanted to
- // XXXX support compression later I guess. So, we need to copy here.
- char *diff_from_nt, *diff_to_nt;
- diff_from_nt = tor_memdup_nulterm(diff_from, len_from);
- diff_to_nt = tor_memdup_nulterm(diff_to, len_to);
- // XXXX ugh; this is going to calculate the SHA3 of both its
- // XXXX inputs again, even though we already have that. Maybe it's time
- // XXXX to change the API here?
- consensus_diff = consensus_diff_generate(diff_from_nt, diff_to_nt);
- tor_free(diff_from_nt);
- tor_free(diff_to_nt);
- }
- if (!consensus_diff) {
- /* Couldn't generate consensus; we'll leave the reply blank. */
- return WQ_RPL_REPLY;
- }
- /* Send the reply */
- job->body_out = (uint8_t *) consensus_diff;
- job->bodylen_out = strlen(consensus_diff);
- cdm_labels_prepend_sha3(&job->labels_out, job->body_out, job->bodylen_out);
- config_line_prepend(&job->labels_out, LABEL_FROM_VALID_AFTER,
- lv_from_valid_after);
- config_line_prepend(&job->labels_out, LABEL_VALID_AFTER, lv_to_valid_after);
- config_line_prepend(&job->labels_out, LABEL_FLAVOR, lv_from_flavor);
- config_line_prepend(&job->labels_out, LABEL_FROM_SHA3_DIGEST,
- lv_from_digest);
- config_line_prepend(&job->labels_out, LABEL_TARGET_SHA3_DIGEST,
- lv_to_digest);
- config_line_prepend(&job->labels_out, LABEL_DOCTYPE, DOCTYPE_CONSENSUS_DIFF);
- return WQ_RPL_REPLY;
- }
- /**
- * Helper: release all storage held in <b>job</b>.
- */
- static void
- consensus_diff_worker_job_free(consensus_diff_worker_job_t *job)
- {
- if (!job)
- return;
- tor_free(job->body_out);
- config_free_lines(job->labels_out);
- consensus_cache_entry_decref(job->diff_from);
- consensus_cache_entry_decref(job->diff_to);
- tor_free(job);
- }
- /**
- * Worker function: This function runs in the main thread, and receives
- * a consensus_diff_worker_job_t that the worker thread has already
- * processed.
- */
- static void
- consensus_diff_worker_replyfn(void *work_)
- {
- tor_assert(in_main_thread());
- tor_assert(work_);
- consensus_diff_worker_job_t *job = work_;
- const char *lv_from_digest =
- consensus_cache_entry_get_value(job->diff_from, LABEL_SHA3_DIGEST);
- const char *lv_to_digest =
- consensus_cache_entry_get_value(job->diff_to, LABEL_SHA3_DIGEST);
- const char *lv_flavor =
- consensus_cache_entry_get_value(job->diff_to, LABEL_FLAVOR);
- if (BUG(lv_from_digest == NULL))
- lv_from_digest = "???"; // LCOV_EXCL_LINE
- if (BUG(lv_to_digest == NULL))
- lv_to_digest = "???"; // LCOV_EXCL_LINE
- uint8_t from_sha3[DIGEST256_LEN];
- uint8_t to_sha3[DIGEST256_LEN];
- int flav = -1;
- int cache = 1;
- if (BUG(cdm_entry_get_sha3_value(from_sha3, job->diff_from,
- LABEL_SHA3_DIGEST) < 0))
- cache = 0;
- if (BUG(cdm_entry_get_sha3_value(to_sha3, job->diff_to,
- LABEL_SHA3_DIGEST) < 0))
- cache = 0;
- if (BUG(lv_flavor == NULL)) {
- cache = 0;
- } else if ((flav = networkstatus_parse_flavor_name(lv_flavor)) < 0) {
- cache = 0;
- }
- int status;
- consensus_cache_entry_handle_t *handle = NULL;
- if (job->body_out && job->bodylen_out && job->labels_out) {
- /* Success! Store the results */
- log_info(LD_DIRSERV, "Adding consensus diff from %s to %s",
- lv_from_digest, lv_to_digest);
- consensus_cache_entry_t *ent =
- consensus_cache_add(cdm_cache_get(), job->labels_out,
- job->body_out,
- job->bodylen_out);
- status = CDM_DIFF_PRESENT;
- handle = consensus_cache_entry_handle_new(ent);
- consensus_cache_entry_decref(ent);
- } else {
- /* Failure! Nothing to do but complain */
- log_warn(LD_DIRSERV,
- "Worker was unable to compute consensus diff "
- "from %s to %s", lv_from_digest, lv_to_digest);
- /* Cache this error so we don't try to compute this one again. */
- status = CDM_DIFF_ERROR;
- }
- if (cache)
- cdm_diff_ht_set_status(flav, from_sha3, to_sha3, status, handle);
- else
- consensus_cache_entry_handle_free(handle);
- consensus_diff_worker_job_free(job);
- }
- /**
- * Queue the job of computing the diff from <b>diff_from</b> to <b>diff_to</b>
- * in a worker thread.
- */
- static int
- consensus_diff_queue_diff_work(consensus_cache_entry_t *diff_from,
- consensus_cache_entry_t *diff_to)
- {
- tor_assert(in_main_thread());
- consensus_cache_entry_incref(diff_from);
- consensus_cache_entry_incref(diff_to);
- consensus_diff_worker_job_t *job = tor_malloc_zero(sizeof(*job));
- job->diff_from = diff_from;
- job->diff_to = diff_to;
- /* Make sure body is mapped. */
- const uint8_t *body;
- size_t bodylen;
- int r1 = consensus_cache_entry_get_body(diff_from, &body, &bodylen);
- int r2 = consensus_cache_entry_get_body(diff_to, &body, &bodylen);
- if (r1 < 0 || r2 < 0)
- goto err;
- workqueue_entry_t *work;
- work = cpuworker_queue_work(consensus_diff_worker_threadfn,
- consensus_diff_worker_replyfn,
- job);
- if (!work)
- goto err;
- return 0;
- err:
- consensus_diff_worker_job_free(job); // includes decrefs.
- return -1;
- }
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