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tor/src/or/consdiffmgr.c
Nick Mathewson fd437f2a02 Remove special-casing for NO_METHOD in consdiffmgr.c
2017-05-02 08:37:57 -04:00

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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"
/**
* 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, 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"
/* 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"
/* 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
};
/** 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);
}
/** 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 = {
/* .cache_max_age_hours = */ 24 * 90,
// 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_diff_queue_diff_work(consensus_cache_entry_t *diff_from,
consensus_cache_entry_t *diff_to);
static void consdiffmgr_set_cache_flags(void);
/* Just gzip consensuses for now. */
#define COMPRESS_CONSENSUS_WITH GZIP_METHOD
/* =====
* 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_)
/** 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)
{
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 (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 <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) > 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. */
consdiffmgr_ensure_space_for_files(1);
{
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, LABEL_SHA3_DIGEST_UNCOMPRESSED,
(const uint8_t *)consensus, bodylen);
char *body_compressed = NULL;
size_t size_compressed = 0;
if (tor_compress(&body_compressed, &size_compressed,
consensus, bodylen, COMPRESS_CONSENSUS_WITH) < 0) {
config_free_lines(labels);
return -1;
}
cdm_labels_prepend_sha3(&labels, LABEL_SHA3_DIGEST,
(const uint8_t *)body_compressed, size_compressed);
config_line_prepend(&labels, LABEL_COMPRESSION_TYPE,
compression_method_get_name(COMPRESS_CONSENSUS_WITH));
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 *)body_compressed,
size_compressed);
tor_free(body_compressed);
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,
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;
}
*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_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);
}
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.
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_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);
} 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_UNCOMPRESSED)<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;
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();
cdm_cache_loaded = 1;
}
for (int flav = 0; flav < N_CONSENSUS_FLAVORS; ++flav) {
consdiffmgr_rescan_flavor_((consensus_flavor_t) flav);
}
cdm_cache_dirty = 0;
}
/**
* 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.
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);
consensus_cache_delete_pending(cache, 1);
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);
}
consensus_cache_free(cons_diff_cache);
cons_diff_cache = NULL;
}
/* =====
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;
/**
* 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_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_UNCOMPRESSED);
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);
/* 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;
{
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;
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);
unsigned u;
for (u = 1; u < n_diff_compression_methods(); ++u) {
compress_method_t method = compress_diffs_with[u];
const char *methodname = compression_method_get_name(method);
char *result;
size_t sz;
if (0 == tor_compress(&result, &sz, consensus_diff, difflen, method)) {
job->out[u].body = (uint8_t*)result;
job->out[u].bodylen = sz;
job->out[u].labels = config_lines_dup(common_labels);
cdm_labels_prepend_sha3(&job->out[u].labels, LABEL_SHA3_DIGEST,
job->out[u].body,
job->out[u].bodylen);
config_line_prepend(&job->out[u].labels,
LABEL_COMPRESSION_TYPE,
methodname);
}
}
config_free_lines(common_labels);
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;
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_UNCOMPRESSED);
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_UNCOMPRESSED) < 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;
}
int status = CDM_DIFF_ERROR;
consensus_cache_entry_handle_t *handles[ARRAY_LENGTH(compress_diffs_with)];
memset(handles, 0, sizeof(handles));
consdiffmgr_ensure_space_for_files(n_diff_compression_methods());
unsigned u;
for (u = 0; u < n_diff_compression_methods(); ++u) {
compress_method_t method = compress_diffs_with[u];
uint8_t *body_out = job->out[u].body;
size_t bodylen_out = job->out[u].bodylen;
config_line_t *labels = job->out[u].labels;
const char *methodname = compression_method_get_name(method);
if (body_out && bodylen_out && labels) {
/* Success! Store the results */
log_info(LD_DIRSERV, "Adding consensus diff from %s to %s, "
"compressed with %s",
lv_from_digest, lv_to_digest, methodname);
consensus_cache_entry_t *ent =
consensus_cache_add(cdm_cache_get(),
labels,
body_out,
bodylen_out);
status = CDM_DIFF_PRESENT;
handles[u] = consensus_cache_entry_handle_new(ent);
consensus_cache_entry_decref(ent);
}
}
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;
}
for (u = 0; u < ARRAY_LENGTH(handles); ++u) {
compress_method_t method = compress_diffs_with[u];
if (cache) {
cdm_diff_ht_set_status(flav, from_sha3, to_sha3, method, status,
handles[u]);
} 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(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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