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Diffstat (limited to 'src/feature/dircache/consdiffmgr.c')
| -rw-r--r-- | src/feature/dircache/consdiffmgr.c | 1945 |
1 files changed, 1945 insertions, 0 deletions
diff --git a/src/feature/dircache/consdiffmgr.c b/src/feature/dircache/consdiffmgr.c new file mode 100644 index 0000000000..025361fa60 --- /dev/null +++ b/src/feature/dircache/consdiffmgr.c @@ -0,0 +1,1945 @@ +/* Copyright (c) 2017-2019, 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 "core/or/or.h" +#include "app/config/config.h" +#include "feature/dircache/conscache.h" +#include "feature/dircommon/consdiff.h" +#include "feature/dircache/consdiffmgr.h" +#include "core/mainloop/cpuworker.h" +#include "feature/nodelist/networkstatus.h" +#include "feature/dirparse/ns_parse.h" +#include "lib/evloop/compat_libevent.h" +#include "lib/evloop/workqueue.h" +#include "lib/compress/compress.h" +#include "lib/encoding/confline.h" + +#include "feature/nodelist/networkstatus_st.h" +#include "feature/nodelist/networkstatus_voter_info_st.h" + +/** + * 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" +/* The fresh-until time for a consensus (or for the target consensus of a + * diff), encoded as ISO UTC. */ +#define LABEL_FRESH_UNTIL "consensus-fresh-until" +/* The valid-until time for a consensus (or for the target consensus of a + * diff), encoded as ISO UTC. */ +#define LABEL_VALID_UNTIL "consensus-valid-until" +/* Comma-separated list of hex-encoded identity digests for the voting + * authorities. */ +#define LABEL_SIGNATORIES "consensus-signatories" +/* A hex encoded SHA3 digest of the object, as compressed (if any) */ +#define LABEL_SHA3_DIGEST "sha3-digest" +/* A hex encoded SHA3 digest of the object before compression. */ +#define LABEL_SHA3_DIGEST_UNCOMPRESSED "sha3-digest-uncompressed" +/* A hex encoded SHA3 digest-as-signed of a consensus */ +#define LABEL_SHA3_DIGEST_AS_SIGNED "sha3-digest-as-signed" +/* The flavor of the consensus or consensuses diff */ +#define LABEL_FLAVOR "consensus-flavor" +/* Diff only: the SHA3 digest-as-signed of the source consensus. */ +#define LABEL_FROM_SHA3_DIGEST "from-sha3-digest" +/* Diff only: the SHA3 digest-in-full 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" +/* What kind of compression was used? */ +#define LABEL_COMPRESSION_TYPE "compression" +/** @} */ + +#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; + +/** Which methods do we use for precompressing diffs? */ +static const compress_method_t compress_diffs_with[] = { + NO_METHOD, + GZIP_METHOD, +#ifdef HAVE_LZMA + LZMA_METHOD, +#endif +#ifdef HAVE_ZSTD + ZSTD_METHOD, +#endif +}; + +/** + * Event for rescanning the cache. + */ +static mainloop_event_t *consdiffmgr_rescan_ev = NULL; + +static void consdiffmgr_rescan_cb(mainloop_event_t *ev, void *arg); +static void mark_cdm_cache_dirty(void); + +/** How many different methods will we try to use for diff compression? */ +STATIC unsigned +n_diff_compression_methods(void) +{ + return ARRAY_LENGTH(compress_diffs_with); +} + +/** Which methods do we use for precompressing consensuses? */ +static const compress_method_t compress_consensus_with[] = { + ZLIB_METHOD, +#ifdef HAVE_LZMA + LZMA_METHOD, +#endif +#ifdef HAVE_ZSTD + ZSTD_METHOD, +#endif +}; + +/** How many different methods will we try to use for diff compression? */ +STATIC unsigned +n_consensus_compression_methods(void) +{ + return ARRAY_LENGTH(compress_consensus_with); +} + +/** For which compression method do we retain old consensuses? There's no + * need to keep all of them, since we won't be serving them. We'll + * go with ZLIB_METHOD because it's pretty fast and everyone has it. + */ +#define RETAIN_CONSENSUS_COMPRESSED_WITH_METHOD ZLIB_METHOD + +/** Handles pointing to the latest consensus entries as compressed and + * stored. */ +static consensus_cache_entry_handle_t * + latest_consensus[N_CONSENSUS_FLAVORS] + [ARRAY_LENGTH(compress_consensus_with)]; + +/** 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]; + /** Method by which the diff is compressed. (part of the ht key */ + compress_method_t compress_method; + + /** 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 = { + // XXXX I'd like to make this number bigger, but it interferes with the + // XXXX seccomp2 syscall filter, which tops out at BPF_MAXINS (4096) + // XXXX rules. + /* .cache_max_num = */ 128 +}; + +static int consdiffmgr_ensure_space_for_files(int n); +static int consensus_queue_compression_work(const char *consensus, + const networkstatus_t *as_parsed); +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 + 2]; + memcpy(tmp, diff->from_sha3, DIGEST256_LEN); + tmp[DIGEST256_LEN] = (uint8_t) diff->flavor; + tmp[DIGEST256_LEN+1] = (uint8_t) diff->compress_method; + 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 && + diff1->compress_method == diff2->compress_method; +} + +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_) + +#define cdm_diff_free(diff) \ + FREE_AND_NULL(cdm_diff_t, cdm_diff_free_, (diff)) + +/** 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, + compress_method_t method) +{ + 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); + ent->compress_method = method; + 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; + unsigned u; + int result = 0; + for (u = 0; u < n_diff_compression_methods(); ++u) { + compress_method_t method = compress_diffs_with[u]; + memset(&search, 0, sizeof(cdm_diff_t)); + search.flavor = flav; + search.compress_method = method; + 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); + result = 1; + continue; + } + ent = cdm_diff_new(flav, from_sha3, target_sha3, method); + ent->cdm_diff_status = CDM_DIFF_IN_PROGRESS; + HT_INSERT(cdm_diff_ht, &cdm_diff_ht, ent); + } + return result; +} + +/** + * 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, + compress_method_t method, + int status, + consensus_cache_entry_handle_t *handle) +{ + if (handle == NULL) { + tor_assert_nonfatal(status != CDM_DIFF_PRESENT); + } + + struct cdm_diff_t search, *ent; + memset(&search, 0, sizeof(cdm_diff_t)); + search.flavor = flav; + search.compress_method = method, + 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, method); + 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 (BUG((*diff)->entry == NULL) || + 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(); + } + consdiffmgr_rescan_ev = + mainloop_event_postloop_new(consdiffmgr_rescan_cb, NULL); + mark_cdm_cache_dirty(); + 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 <b>label</b> as its label. + */ +static void +cdm_labels_prepend_sha3(config_line_t **labels, + const char *label, + 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, 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)) { + result = smartlist_get(matches, 0); + } + smartlist_free(matches); + + return result; +} + +/** Return the maximum age (in seconds) of consensuses that we should consider + * storing. The available space in the directory may impose additional limits + * on how much we store. */ +static int32_t +get_max_age_to_cache(void) +{ + const int32_t DEFAULT_MAX_AGE_TO_CACHE = 8192; + const int32_t MIN_MAX_AGE_TO_CACHE = 0; + const int32_t MAX_MAX_AGE_TO_CACHE = 8192; + const char MAX_AGE_TO_CACHE_NAME[] = "max-consensus-age-to-cache-for-diff"; + + const or_options_t *options = get_options(); + + if (options->MaxConsensusAgeForDiffs) { + const int v = options->MaxConsensusAgeForDiffs; + if (v >= MAX_MAX_AGE_TO_CACHE * 3600) + return MAX_MAX_AGE_TO_CACHE; + else + return v; + } + + /* The parameter is in hours, so we multiply */ + return 3600 * networkstatus_get_param(NULL, + MAX_AGE_TO_CACHE_NAME, + DEFAULT_MAX_AGE_TO_CACHE, + MIN_MAX_AGE_TO_CACHE, + MAX_MAX_AGE_TO_CACHE); +} + +/** + * 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() - get_max_age_to_cache()) { + 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. */ + return consensus_queue_compression_work(consensus, as_parsed); +} + +/** + * 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; + } +} + +/** Return i such that compress_consensus_with[i] == method. Return + * -1 if no such i exists. */ +static int +consensus_compression_method_pos(compress_method_t method) +{ + unsigned i; + for (i = 0; i < n_consensus_compression_methods(); ++i) { + if (compress_consensus_with[i] == method) { + return i; + } + } + return -1; +} + +/** + * If we know a consensus with the flavor <b>flavor</b> compressed with + * <b>method</b>, set *<b>entry_out</b> to that value. Return values are as + * for consdiffmgr_find_diff_from(). + */ +consdiff_status_t +consdiffmgr_find_consensus(struct consensus_cache_entry_t **entry_out, + consensus_flavor_t flavor, + compress_method_t method) +{ + tor_assert(entry_out); + tor_assert((int)flavor < N_CONSENSUS_FLAVORS); + + int pos = consensus_compression_method_pos(method); + if (pos < 0) { + // We don't compress consensuses with this method. + return CONSDIFF_NOT_FOUND; + } + consensus_cache_entry_handle_t *handle = latest_consensus[flavor][pos]; + if (!handle) + return CONSDIFF_NOT_FOUND; + *entry_out = consensus_cache_entry_handle_get(handle); + if (*entry_out) + return CONSDIFF_AVAILABLE; + else + return CONSDIFF_NOT_FOUND; +} + +/** + * 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, + compress_method_t method) +{ + 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; + search.compress_method = method; + 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; + } + + if (BUG(ent->entry == NULL)) { + return CONSDIFF_NOT_FOUND; + } + *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 /* 0 */ +} + +/** + * 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() - get_max_age_to_cache(); + + 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_UNCOMPRESSED); + 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); + } + + // 3. Delete all consensuses except the most recent that are compressed with + // an un-preferred method. + 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_uncompressed = + consensus_cache_entry_get_value(most_recent, + LABEL_SHA3_DIGEST_UNCOMPRESSED); + const char *retain_methodname = compression_method_get_name( + RETAIN_CONSENSUS_COMPRESSED_WITH_METHOD); + + if (BUG(most_recent_sha3_uncompressed == NULL)) + continue; + SMARTLIST_FOREACH_BEGIN(consensuses, consensus_cache_entry_t *, ent) { + const char *lv_sha3_uncompressed = + consensus_cache_entry_get_value(ent, LABEL_SHA3_DIGEST_UNCOMPRESSED); + if (BUG(! lv_sha3_uncompressed)) + continue; + if (!strcmp(lv_sha3_uncompressed, most_recent_sha3_uncompressed)) + continue; // This _is_ the most recent. + const char *lv_methodname = + consensus_cache_entry_get_value(ent, LABEL_COMPRESSION_TYPE); + if (! lv_methodname || strcmp(lv_methodname, retain_methodname)) { + consensus_cache_entry_mark_for_removal(ent); + ++n_to_delete; + } + } SMARTLIST_FOREACH_END(ent); + } + + smartlist_free(objects); + smartlist_free(consensuses); + smartlist_free(diffs); + + // Actually remove files, if they're not used. + consensus_cache_delete_pending(cdm_cache_get(), 0); + 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) +{ + if (cfg) + memcpy(&consdiff_cfg, cfg, sizeof(consdiff_cfg)); + + (void) cdm_cache_get(); +} + +/** + * Tell the sandbox (if any) configured by <b>cfg</b> to allow the + * operations that the consensus diff manager will need. + */ +int +consdiffmgr_register_with_sandbox(struct sandbox_cfg_elem **cfg) +{ + return consensus_cache_register_with_sandbox(cdm_cache_get(), cfg); +} + +/** + * 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; + + // Deconfuse coverity about the possibility of sha3_received being + // uninitialized + tor_assert(r <= 0); + + 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. + const char *methodname = compression_method_get_name( + RETAIN_CONSENSUS_COMPRESSED_WITH_METHOD); + + 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_filter_list(matches, LABEL_COMPRESSION_TYPE, methodname); + 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_UNCOMPRESSED) < 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); + /* Since we are not going to serve this as the most recent consensus + * any more, we should stop keeping it mmap'd when it's not in use. + */ + consensus_cache_entry_mark_for_aggressive_release(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 (cdm_entry_get_sha3_value(this_sha3, c, + LABEL_SHA3_DIGEST_AS_SIGNED)<0) { + // Not actually a bug, since we might be running with a directory + // with stale files from before the #22143 fixes. + continue; + } + 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 the latest consensuses and add their handles to + * latest_consensus + */ +static void +consdiffmgr_consensus_load(void) +{ + smartlist_t *matches = smartlist_new(); + for (int flav = 0; flav < N_CONSENSUS_FLAVORS; ++flav) { + const char *flavname = networkstatus_get_flavor_name(flav); + smartlist_clear(matches); + 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) + continue; // no consensuses. + const char *most_recent_sha3 = + consensus_cache_entry_get_value(most_recent, + LABEL_SHA3_DIGEST_UNCOMPRESSED); + if (BUG(most_recent_sha3 == NULL)) + continue; // LCOV_EXCL_LINE + consensus_cache_filter_list(matches, LABEL_SHA3_DIGEST_UNCOMPRESSED, + most_recent_sha3); + + // Everything that remains matches the most recent consensus of this + // flavor. + SMARTLIST_FOREACH_BEGIN(matches, consensus_cache_entry_t *, ent) { + const char *lv_compression = + consensus_cache_entry_get_value(ent, LABEL_COMPRESSION_TYPE); + compress_method_t method = + compression_method_get_by_name(lv_compression); + int pos = consensus_compression_method_pos(method); + if (pos < 0) + continue; + consensus_cache_entry_handle_free(latest_consensus[flav][pos]); + latest_consensus[flav][pos] = consensus_cache_entry_handle_new(ent); + } SMARTLIST_FOREACH_END(ent); + } + smartlist_free(matches); +} + +/** + * 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; + const char *lv_compression = + consensus_cache_entry_get_value(diff, LABEL_COMPRESSION_TYPE); + compress_method_t method = NO_METHOD; + if (lv_compression) { + method = compression_method_get_by_name(lv_compression); + if (method == UNKNOWN_METHOD) { + 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, + method, + 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(); + consdiffmgr_consensus_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; +} + +/** Callback wrapper for consdiffmgr_rescan */ +static void +consdiffmgr_rescan_cb(mainloop_event_t *ev, void *arg) +{ + (void)ev; + (void)arg; + consdiffmgr_rescan(); +} + +/** Mark the cache as dirty, and schedule a rescan event. */ +static void +mark_cdm_cache_dirty(void) +{ + cdm_cache_dirty = 1; + tor_assert(consdiffmgr_rescan_ev); + mainloop_event_activate(consdiffmgr_rescan_ev); +} + +/** + * Helper: compare two files by their from-valid-after and valid-after labels, + * trying to sort in ascending order by from-valid-after (when present) and + * valid-after (when not). Place everything that has neither label first in + * the list. + */ +static int +compare_by_staleness_(const void **a, const void **b) +{ + const consensus_cache_entry_t *e1 = *a; + const consensus_cache_entry_t *e2 = *b; + const char *va1, *fva1, *va2, *fva2; + va1 = consensus_cache_entry_get_value(e1, LABEL_VALID_AFTER); + va2 = consensus_cache_entry_get_value(e2, LABEL_VALID_AFTER); + fva1 = consensus_cache_entry_get_value(e1, LABEL_FROM_VALID_AFTER); + fva2 = consensus_cache_entry_get_value(e2, LABEL_FROM_VALID_AFTER); + + if (fva1) + va1 = fva1; + if (fva2) + va2 = fva2; + + /* See note about iso-encoded values in compare_by_valid_after_. Also note + * that missing dates will get placed first. */ + return strcmp_opt(va1, va2); +} + +/** If there are not enough unused filenames to store <b>n</b> files, then + * delete old consensuses until there are. (We have to keep track of the + * number of filenames because of the way that the seccomp2 cache works.) + * + * Return 0 on success, -1 on failure. + **/ +static int +consdiffmgr_ensure_space_for_files(int n) +{ + consensus_cache_t *cache = cdm_cache_get(); + if (consensus_cache_get_n_filenames_available(cache) >= n) { + // there are already enough unused filenames. + return 0; + } + // Try a cheap deletion of stuff that's waiting to get deleted. + consensus_cache_delete_pending(cache, 0); + if (consensus_cache_get_n_filenames_available(cache) >= n) { + // okay, _that_ made enough filenames available. + return 0; + } + // Let's get more assertive: clean out unused stuff, and force-remove + // the files that we can. + consdiffmgr_cleanup(); + consensus_cache_delete_pending(cache, 1); + const int n_to_remove = n - consensus_cache_get_n_filenames_available(cache); + if (n_to_remove <= 0) { + // okay, finally! + return 0; + } + + // At this point, we're going to have to throw out objects that will be + // missed. Too bad! + smartlist_t *objects = smartlist_new(); + consensus_cache_find_all(objects, cache, NULL, NULL); + smartlist_sort(objects, compare_by_staleness_); + int n_marked = 0; + SMARTLIST_FOREACH_BEGIN(objects, consensus_cache_entry_t *, ent) { + consensus_cache_entry_mark_for_removal(ent); + if (++n_marked >= n_to_remove) + break; + } SMARTLIST_FOREACH_END(ent); + smartlist_free(objects); + + consensus_cache_delete_pending(cache, 1); + + if (consensus_cache_may_overallocate(cache)) { + /* If we're allowed to throw extra files into the cache, let's do so + * rather getting upset. + */ + return 0; + } + + if (BUG(n_marked < n_to_remove)) + return -1; + else + return 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); + } + int i; + unsigned j; + for (i = 0; i < N_CONSENSUS_FLAVORS; ++i) { + for (j = 0; j < n_consensus_compression_methods(); ++j) { + consensus_cache_entry_handle_free(latest_consensus[i][j]); + } + } + memset(latest_consensus, 0, sizeof(latest_consensus)); + consensus_cache_free(cons_diff_cache); + cons_diff_cache = NULL; + mainloop_event_free(consdiffmgr_rescan_ev); +} + +/* ===== + Thread workers + =====*/ + +typedef struct compressed_result_t { + config_line_t *labels; + /** + * Output: Body of the diff, as compressed. + */ + uint8_t *body; + /** + * Output: length of body_out + */ + size_t bodylen; +} compressed_result_t; + +/** + * Compress the bytestring <b>input</b> of length <b>len</b> using the + * <n>n_methods</b> compression methods listed in the array <b>methods</b>. + * + * For each successful compression, set the fields in the <b>results_out</b> + * array in the position corresponding to the compression method. Use + * <b>labels_in</b> as a basis for the labels of the result. + * + * Return 0 if all compression succeeded; -1 if any failed. + */ +static int +compress_multiple(compressed_result_t *results_out, int n_methods, + const compress_method_t *methods, + const uint8_t *input, size_t len, + const config_line_t *labels_in) +{ + int rv = 0; + int i; + for (i = 0; i < n_methods; ++i) { + compress_method_t method = methods[i]; + const char *methodname = compression_method_get_name(method); + char *result; + size_t sz; + if (0 == tor_compress(&result, &sz, (const char*)input, len, method)) { + results_out[i].body = (uint8_t*)result; + results_out[i].bodylen = sz; + results_out[i].labels = config_lines_dup(labels_in); + cdm_labels_prepend_sha3(&results_out[i].labels, LABEL_SHA3_DIGEST, + results_out[i].body, + results_out[i].bodylen); + config_line_prepend(&results_out[i].labels, + LABEL_COMPRESSION_TYPE, + methodname); + } else { + rv = -1; + } + } + return rv; +} + +/** + * Given an array of <b>n</b> compressed_result_t in <b>results</b>, + * as produced by compress_multiple, store them all into the + * consdiffmgr, and store handles to them in the <b>handles_out</b> + * array. + * + * Return CDM_DIFF_PRESENT if any was stored, and CDM_DIFF_ERROR if none + * was stored. + */ +static cdm_diff_status_t +store_multiple(consensus_cache_entry_handle_t **handles_out, + int n, + const compress_method_t *methods, + const compressed_result_t *results, + const char *description) +{ + cdm_diff_status_t status = CDM_DIFF_ERROR; + consdiffmgr_ensure_space_for_files(n); + + int i; + for (i = 0; i < n; ++i) { + compress_method_t method = methods[i]; + uint8_t *body_out = results[i].body; + size_t bodylen_out = results[i].bodylen; + config_line_t *labels = results[i].labels; + const char *methodname = compression_method_get_name(method); + if (body_out && bodylen_out && labels) { + /* Success! Store the results */ + log_info(LD_DIRSERV, "Adding %s, compressed with %s", + description, methodname); + + consensus_cache_entry_t *ent = + consensus_cache_add(cdm_cache_get(), + labels, + body_out, + bodylen_out); + if (ent == NULL) { + static ratelim_t cant_store_ratelim = RATELIM_INIT(5*60); + log_fn_ratelim(&cant_store_ratelim, LOG_WARN, LD_FS, + "Unable to store object %s compressed with %s.", + description, methodname); + continue; + } + + status = CDM_DIFF_PRESENT; + handles_out[i] = consensus_cache_entry_handle_new(ent); + consensus_cache_entry_decref(ent); + } + } + return status; +} + +/** + * 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 and bodies */ + compressed_result_t out[ARRAY_LENGTH(compress_diffs_with)]; +} consensus_diff_worker_job_t; + +/** Given a consensus_cache_entry_t, check whether it has a label claiming + * that it was compressed. If so, uncompress its contents into <b>out</b> and + * set <b>outlen</b> to hold their size. If not, just copy the body into + * <b>out</b> and set <b>outlen</b> to its length. Return 0 on success, + * -1 on failure. + * + * In all cases, the output is nul-terminated. */ +STATIC int +uncompress_or_copy(char **out, size_t *outlen, + consensus_cache_entry_t *ent) +{ + const uint8_t *body; + size_t bodylen; + + if (consensus_cache_entry_get_body(ent, &body, &bodylen) < 0) + return -1; + + const char *lv_compression = + consensus_cache_entry_get_value(ent, LABEL_COMPRESSION_TYPE); + compress_method_t method = NO_METHOD; + + if (lv_compression) + method = compression_method_get_by_name(lv_compression); + + return tor_uncompress(out, outlen, (const char *)body, bodylen, + method, 1, LOG_WARN); +} + +/** + * 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_to_fresh_until = + consensus_cache_entry_get_value(job->diff_to, LABEL_FRESH_UNTIL); + const char *lv_to_valid_until = + consensus_cache_entry_get_value(job->diff_to, LABEL_VALID_UNTIL); + const char *lv_to_signatories = + consensus_cache_entry_get_value(job->diff_to, LABEL_SIGNATORIES); + 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_AS_SIGNED); + 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_UNCOMPRESSED); + + if (! lv_from_digest) { + /* This isn't a bug right now, since it can happen if you're migrating + * from an older version of master to a newer one. The older ones didn't + * annotate their stored consensus objects with sha3-digest-as-signed. + */ + return WQ_RPL_REPLY; // LCOV_EXCL_LINE + } + + /* All these values are mandatory on the input */ + if (BUG(!lv_to_valid_after) || + BUG(!lv_from_valid_after) || + 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; + { + char *diff_from_nt = NULL, *diff_to_nt = NULL; + size_t diff_from_nt_len, diff_to_nt_len; + + if (uncompress_or_copy(&diff_from_nt, &diff_from_nt_len, + job->diff_from) < 0) { + return WQ_RPL_REPLY; + } + if (uncompress_or_copy(&diff_to_nt, &diff_to_nt_len, + job->diff_to) < 0) { + tor_free(diff_from_nt); + return WQ_RPL_REPLY; + } + tor_assert(diff_from_nt); + tor_assert(diff_to_nt); + + // 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; + } + + /* Compress the results and send the reply */ + tor_assert(compress_diffs_with[0] == NO_METHOD); + size_t difflen = strlen(consensus_diff); + job->out[0].body = (uint8_t *) consensus_diff; + job->out[0].bodylen = difflen; + + config_line_t *common_labels = NULL; + if (lv_to_valid_until) + config_line_prepend(&common_labels, LABEL_VALID_UNTIL, lv_to_valid_until); + if (lv_to_fresh_until) + config_line_prepend(&common_labels, LABEL_FRESH_UNTIL, lv_to_fresh_until); + if (lv_to_signatories) + config_line_prepend(&common_labels, LABEL_SIGNATORIES, lv_to_signatories); + cdm_labels_prepend_sha3(&common_labels, + LABEL_SHA3_DIGEST_UNCOMPRESSED, + job->out[0].body, + job->out[0].bodylen); + config_line_prepend(&common_labels, LABEL_FROM_VALID_AFTER, + lv_from_valid_after); + config_line_prepend(&common_labels, LABEL_VALID_AFTER, + lv_to_valid_after); + config_line_prepend(&common_labels, LABEL_FLAVOR, lv_from_flavor); + config_line_prepend(&common_labels, LABEL_FROM_SHA3_DIGEST, + lv_from_digest); + config_line_prepend(&common_labels, LABEL_TARGET_SHA3_DIGEST, + lv_to_digest); + config_line_prepend(&common_labels, LABEL_DOCTYPE, + DOCTYPE_CONSENSUS_DIFF); + + job->out[0].labels = config_lines_dup(common_labels); + cdm_labels_prepend_sha3(&job->out[0].labels, + LABEL_SHA3_DIGEST, + job->out[0].body, + job->out[0].bodylen); + + compress_multiple(job->out+1, + n_diff_compression_methods()-1, + compress_diffs_with+1, + (const uint8_t*)consensus_diff, difflen, common_labels); + + config_free_lines(common_labels); + return WQ_RPL_REPLY; +} + +#define consensus_diff_worker_job_free(job) \ + FREE_AND_NULL(consensus_diff_worker_job_t, \ + consensus_diff_worker_job_free_, (job)) + +/** + * 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; + unsigned u; + for (u = 0; u < n_diff_compression_methods(); ++u) { + config_free_lines(job->out[u].labels); + tor_free(job->out[u].body); + } + 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_AS_SIGNED); + const char *lv_to_digest = + consensus_cache_entry_get_value(job->diff_to, + LABEL_SHA3_DIGEST_UNCOMPRESSED); + 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_AS_SIGNED) < 0)) + cache = 0; + if (BUG(cdm_entry_get_sha3_value(to_sha3, job->diff_to, + LABEL_SHA3_DIGEST_UNCOMPRESSED) < 0)) + cache = 0; + if (BUG(lv_flavor == NULL)) { + cache = 0; + } else if ((flav = networkstatus_parse_flavor_name(lv_flavor)) < 0) { + cache = 0; + } + + consensus_cache_entry_handle_t *handles[ARRAY_LENGTH(compress_diffs_with)]; + memset(handles, 0, sizeof(handles)); + + char description[128]; + tor_snprintf(description, sizeof(description), + "consensus diff from %s to %s", + lv_from_digest, lv_to_digest); + + int status = store_multiple(handles, + n_diff_compression_methods(), + compress_diffs_with, + job->out, + description); + + if (status != CDM_DIFF_PRESENT) { + /* 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; + } + + unsigned u; + for (u = 0; u < ARRAY_LENGTH(handles); ++u) { + compress_method_t method = compress_diffs_with[u]; + if (cache) { + consensus_cache_entry_handle_t *h = handles[u]; + int this_status = status; + if (h == NULL) { + this_status = CDM_DIFF_ERROR; + } + tor_assert_nonfatal(h != NULL || this_status == CDM_DIFF_ERROR); + cdm_diff_ht_set_status(flav, from_sha3, to_sha3, method, this_status, h); + } else { + consensus_cache_entry_handle_free(handles[u]); + } + } + + 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(WQ_PRI_LOW, + 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; +} + +/** + * Holds requests and replies for consensus_compress_workers. + */ +typedef struct consensus_compress_worker_job_t { + char *consensus; + size_t consensus_len; + consensus_flavor_t flavor; + config_line_t *labels_in; + compressed_result_t out[ARRAY_LENGTH(compress_consensus_with)]; +} consensus_compress_worker_job_t; + +#define consensus_compress_worker_job_free(job) \ + FREE_AND_NULL(consensus_compress_worker_job_t, \ + consensus_compress_worker_job_free_, (job)) + +/** + * Free all resources held in <b>job</b> + */ +static void +consensus_compress_worker_job_free_(consensus_compress_worker_job_t *job) +{ + if (!job) + return; + tor_free(job->consensus); + config_free_lines(job->labels_in); + unsigned u; + for (u = 0; u < n_consensus_compression_methods(); ++u) { + config_free_lines(job->out[u].labels); + tor_free(job->out[u].body); + } + tor_free(job); +} +/** + * Worker function. This function runs inside a worker thread and receives + * a consensus_compress_worker_job_t as its input. + */ +static workqueue_reply_t +consensus_compress_worker_threadfn(void *state_, void *work_) +{ + (void)state_; + consensus_compress_worker_job_t *job = work_; + consensus_flavor_t flavor = job->flavor; + const char *consensus = job->consensus; + size_t bodylen = job->consensus_len; + + config_line_t *labels = config_lines_dup(job->labels_in); + const char *flavname = networkstatus_get_flavor_name(flavor); + + cdm_labels_prepend_sha3(&labels, LABEL_SHA3_DIGEST_UNCOMPRESSED, + (const uint8_t *)consensus, bodylen); + { + const char *start, *end; + if (router_get_networkstatus_v3_signed_boundaries(consensus, + &start, &end) < 0) { + start = consensus; + end = consensus+bodylen; + } + cdm_labels_prepend_sha3(&labels, LABEL_SHA3_DIGEST_AS_SIGNED, + (const uint8_t *)start, + end - start); + } + config_line_prepend(&labels, LABEL_FLAVOR, flavname); + config_line_prepend(&labels, LABEL_DOCTYPE, DOCTYPE_CONSENSUS); + + compress_multiple(job->out, + n_consensus_compression_methods(), + compress_consensus_with, + (const uint8_t*)consensus, bodylen, labels); + config_free_lines(labels); + return WQ_RPL_REPLY; +} + +/** + * Worker function: This function runs in the main thread, and receives + * a consensus_diff_compress_job_t that the worker thread has already + * processed. + */ +static void +consensus_compress_worker_replyfn(void *work_) +{ + consensus_compress_worker_job_t *job = work_; + + consensus_cache_entry_handle_t *handles[ + ARRAY_LENGTH(compress_consensus_with)]; + memset(handles, 0, sizeof(handles)); + + store_multiple(handles, + n_consensus_compression_methods(), + compress_consensus_with, + job->out, + "consensus"); + mark_cdm_cache_dirty(); + + unsigned u; + consensus_flavor_t f = job->flavor; + tor_assert((int)f < N_CONSENSUS_FLAVORS); + for (u = 0; u < ARRAY_LENGTH(handles); ++u) { + if (handles[u] == NULL) + continue; + consensus_cache_entry_handle_free(latest_consensus[f][u]); + latest_consensus[f][u] = handles[u]; + } + + consensus_compress_worker_job_free(job); +} + +/** + * If true, we compress in worker threads. + */ +static int background_compression = 0; + +/** + * Queue a job to compress <b>consensus</b> and store its compressed + * text in the cache. + */ +static int +consensus_queue_compression_work(const char *consensus, + const networkstatus_t *as_parsed) +{ + tor_assert(consensus); + tor_assert(as_parsed); + + consensus_compress_worker_job_t *job = tor_malloc_zero(sizeof(*job)); + job->consensus = tor_strdup(consensus); + job->consensus_len = strlen(consensus); + job->flavor = as_parsed->flavor; + + char va_str[ISO_TIME_LEN+1]; + char vu_str[ISO_TIME_LEN+1]; + char fu_str[ISO_TIME_LEN+1]; + format_iso_time_nospace(va_str, as_parsed->valid_after); + format_iso_time_nospace(fu_str, as_parsed->fresh_until); + format_iso_time_nospace(vu_str, as_parsed->valid_until); + config_line_append(&job->labels_in, LABEL_VALID_AFTER, va_str); + config_line_append(&job->labels_in, LABEL_FRESH_UNTIL, fu_str); + config_line_append(&job->labels_in, LABEL_VALID_UNTIL, vu_str); + if (as_parsed->voters) { + smartlist_t *hexvoters = smartlist_new(); + SMARTLIST_FOREACH_BEGIN(as_parsed->voters, + networkstatus_voter_info_t *, vi) { + if (smartlist_len(vi->sigs) == 0) + continue; // didn't sign. + char d[HEX_DIGEST_LEN+1]; + base16_encode(d, sizeof(d), vi->identity_digest, DIGEST_LEN); + smartlist_add_strdup(hexvoters, d); + } SMARTLIST_FOREACH_END(vi); + char *signers = smartlist_join_strings(hexvoters, ",", 0, NULL); + config_line_prepend(&job->labels_in, LABEL_SIGNATORIES, signers); + tor_free(signers); + SMARTLIST_FOREACH(hexvoters, char *, cp, tor_free(cp)); + smartlist_free(hexvoters); + } + + if (background_compression) { + workqueue_entry_t *work; + work = cpuworker_queue_work(WQ_PRI_LOW, + consensus_compress_worker_threadfn, + consensus_compress_worker_replyfn, + job); + if (!work) { + consensus_compress_worker_job_free(job); + return -1; + } + + return 0; + } else { + consensus_compress_worker_threadfn(NULL, job); + consensus_compress_worker_replyfn(job); + return 0; + } +} + +/** + * Tell the consdiffmgr backend to compress consensuses in worker threads. + */ +void +consdiffmgr_enable_background_compression(void) +{ + // This isn't the default behavior because it would break unit tests. + background_compression = 1; +} + +/** Read the set of voters from the cached object <b>ent</b> into + * <b>out</b>, as a list of hex-encoded digests. Return 0 on success, + * -1 if no signatories were recorded. */ +int +consensus_cache_entry_get_voter_id_digests(const consensus_cache_entry_t *ent, + smartlist_t *out) +{ + tor_assert(ent); + tor_assert(out); + const char *s; + s = consensus_cache_entry_get_value(ent, LABEL_SIGNATORIES); + if (s == NULL) + return -1; + smartlist_split_string(out, s, ",", SPLIT_SKIP_SPACE|SPLIT_STRIP_SPACE, 0); + return 0; +} + +/** Read the fresh-until time of cached object <b>ent</b> into *<b>out</b> + * and return 0, or return -1 if no such time was recorded. */ +int +consensus_cache_entry_get_fresh_until(const consensus_cache_entry_t *ent, + time_t *out) +{ + tor_assert(ent); + tor_assert(out); + const char *s; + s = consensus_cache_entry_get_value(ent, LABEL_FRESH_UNTIL); + if (s == NULL || parse_iso_time_nospace(s, out) < 0) + return -1; + else + return 0; +} + +/** Read the valid until timestamp from the cached object <b>ent</b> into + * *<b>out</b> and return 0, or return -1 if no such time was recorded. */ +int +consensus_cache_entry_get_valid_until(const consensus_cache_entry_t *ent, + time_t *out) +{ + tor_assert(ent); + tor_assert(out); + + const char *s; + s = consensus_cache_entry_get_value(ent, LABEL_VALID_UNTIL); + if (s == NULL || parse_iso_time_nospace(s, out) < 0) + return -1; + else + return 0; +} + +/** Read the valid after timestamp from the cached object <b>ent</b> into + * *<b>out</b> and return 0, or return -1 if no such time was recorded. */ +int +consensus_cache_entry_get_valid_after(const consensus_cache_entry_t *ent, + time_t *out) +{ + tor_assert(ent); + tor_assert(out); + + const char *s; + s = consensus_cache_entry_get_value(ent, LABEL_VALID_AFTER); + + if (s == NULL || parse_iso_time_nospace(s, out) < 0) + return -1; + else + return 0; +} |