commit ef2a62b2ff0c8db17e146a79034c8e43ee528c86 Author: Alexander Færøy ahf@torproject.org Date: Fri May 12 21:17:09 2017 +0200
Fetch the current consensus from the conscache subsystem.
This patch changes handle_get_current_consensus() to make it read the current consensus document from the consensus caching subsystem.
See: https://bugs.torproject.org/21667 --- src/or/directory.c | 121 ++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 88 insertions(+), 33 deletions(-)
diff --git a/src/or/directory.c b/src/or/directory.c index 4a528f2..946792b 100644 --- a/src/or/directory.c +++ b/src/or/directory.c @@ -13,6 +13,7 @@ #include "config.h" #include "connection.h" #include "connection_edge.h" +#include "conscache.h" #include "consdiff.h" #include "consdiffmgr.h" #include "control.h" @@ -117,7 +118,8 @@ static void dir_routerdesc_download_failed(smartlist_t *failed, int was_descriptor_digests); static void dir_microdesc_download_failed(smartlist_t *failed, int status_code); -static int client_likes_consensus(networkstatus_t *v, const char *want_url); +static int client_likes_consensus(const struct consensus_cache_entry_t *ent, + const char *want_url);
static void connection_dir_close_consensus_fetches( dir_connection_t *except_this_one, const char *resource); @@ -3377,14 +3379,20 @@ accept_encoding_header(void) * consensus, 0 otherwise. */ int -client_likes_consensus(networkstatus_t *v, const char *want_url) +client_likes_consensus(const struct consensus_cache_entry_t *ent, + const char *want_url) { smartlist_t *want_authorities = smartlist_new(); + smartlist_t *voters = smartlist_new(); int need_at_least; int have = 0;
dir_split_resource_into_fingerprints(want_url, want_authorities, NULL, 0); need_at_least = smartlist_len(want_authorities)/2+1; + + if (consensus_cache_entry_get_voters(ent, voters) != 0) + goto done; + SMARTLIST_FOREACH_BEGIN(want_authorities, const char *, d) { char want_digest[DIGEST_LEN]; size_t want_len = strlen(d)/2; @@ -3398,7 +3406,7 @@ client_likes_consensus(networkstatus_t *v, const char *want_url) continue; };
- SMARTLIST_FOREACH_BEGIN(v->voters, networkstatus_voter_info_t *, vi) { + SMARTLIST_FOREACH_BEGIN(voters, networkstatus_voter_info_t *, vi) { if (smartlist_len(vi->sigs) && tor_memeq(vi->identity_digest, want_digest, want_len)) { have++; @@ -3411,8 +3419,11 @@ client_likes_consensus(networkstatus_t *v, const char *want_url) break; } SMARTLIST_FOREACH_END(d);
+ done: SMARTLIST_FOREACH(want_authorities, char *, d, tor_free(d)); smartlist_free(want_authorities); + SMARTLIST_FOREACH(voters, networkstatus_voter_info_t *, v, tor_free(v)); + smartlist_free(voters); return (have >= need_at_least); }
@@ -3619,20 +3630,25 @@ handle_get_frontpage(dir_connection_t *conn, const get_handler_args_t *args) return 0; }
-/** Warn that the consensus <b>v</b> of type <b>flavor</b> is too old and will - * not be served to clients. Rate-limit the warning to avoid logging an entry - * on every request. +/** Warn that the cached consensus <b>cached_consensus</b> of type + * <b>flavor</b> is too old and will not be served to clients. Rate-limit the + * warning to avoid logging an entry on every request. */ static void -warn_consensus_is_too_old(networkstatus_t *v, const char *flavor, time_t now) +warn_consensus_is_too_old(const struct consensus_cache_entry_t *cached_consensus, + const char *flavor, time_t now) { #define TOO_OLD_WARNING_INTERVAL (60*60) static ratelim_t warned = RATELIM_INIT(TOO_OLD_WARNING_INTERVAL); char timestamp[ISO_TIME_LEN+1]; + time_t valid_until; char *dupes;
+ if (consensus_cache_entry_valid_until(cached_consensus, &valid_until)) + return; + if ((dupes = rate_limit_log(&warned, now))) { - format_local_iso_time(timestamp, v->valid_until); + format_local_iso_time(timestamp, valid_until); log_warn(LD_DIRSERV, "Our %s%sconsensus is too old, so we will not " "serve it to clients. It was valid until %s local time and we " "continued to serve it for up to 24 hours after it expired.%s", @@ -3705,6 +3721,35 @@ find_best_diff(const smartlist_t *digests, int flav, return NULL; }
+/** Lookup the cached consensus document by the flavor found in <b>flav</b>. + * The prefered set of compression methods should be listed in the + * <b>compression_methods</b> bitfield. The compression method chosen (if any) + * is stored in <b>compression_used_out</b>. */ +static struct consensus_cache_entry_t * +find_best_consensus(int flav, + unsigned compression_methods, + compress_method_t *compression_used_out) +{ + struct consensus_cache_entry_t *result = NULL; + unsigned u; + + for (u = 0; u < ARRAY_LENGTH(srv_meth_pref_precompressed); ++u) { + compress_method_t method = srv_meth_pref_precompressed[u]; + + if (0 == (compression_methods & (1u<<method))) + continue; + + if (consdiffmgr_find_consensus(&result, flav, + method) == CONSDIFF_AVAILABLE) { + tor_assert_nonfatal(result); + *compression_used_out = method; + return result; + } + } + + return NULL; +} + /** Try to find the best supported compression method possible from a given * <b>compression_methods</b>. Return NO_METHOD if no mutually supported * compression method could be found. */ @@ -3747,7 +3792,6 @@ handle_get_current_consensus(dir_connection_t *conn, /* v3 network status fetch. */ long lifetime = NETWORKSTATUS_CACHE_LIFETIME;
- networkstatus_t *v; time_t now = time(NULL); const char *want_fps = NULL; char *flavor = NULL; @@ -3773,18 +3817,33 @@ handle_get_current_consensus(dir_connection_t *conn, want_fps = url+strlen(CONSENSUS_URL_PREFIX); }
- v = networkstatus_get_latest_consensus_by_flavor(flav); + struct consensus_cache_entry_t *cached_consensus = NULL; + smartlist_t *diff_from_digests = NULL; + compress_method_t compression_used = NO_METHOD; + if (!parse_or_diff_from_header(&diff_from_digests, args->headers)) { + tor_assert(diff_from_digests); + cached_consensus = find_best_diff(diff_from_digests, flav, + args->compression_supported, + &compression_used); + SMARTLIST_FOREACH(diff_from_digests, uint8_t *, d, tor_free(d)); + smartlist_free(diff_from_digests); + } else { + cached_consensus = find_best_consensus(flav, + args->compression_supported, + &compression_used); + }
- if (v && !networkstatus_consensus_reasonably_live(v, now)) { + if (cached_consensus && + !consensus_cache_entry_is_reasonably_live(cached_consensus, now)) { write_http_status_line(conn, 404, "Consensus is too old"); - warn_consensus_is_too_old(v, flavor, now); + warn_consensus_is_too_old(cached_consensus, flavor, now); geoip_note_ns_response(GEOIP_REJECT_NOT_FOUND); tor_free(flavor); goto done; }
- if (v && want_fps && - !client_likes_consensus(v, want_fps)) { + if (cached_consensus && want_fps && + !client_likes_consensus(cached_consensus, want_fps)) { write_http_status_line(conn, 404, "Consensus not signed by sufficient " "number of requested authorities"); geoip_note_ns_response(GEOIP_REJECT_NOT_ENOUGH_SIGS); @@ -3792,37 +3851,30 @@ handle_get_current_consensus(dir_connection_t *conn, goto done; }
- struct consensus_cache_entry_t *cached_diff = NULL; - smartlist_t *diff_from_digests = NULL; - compress_method_t compression_used = NO_METHOD; - if (!parse_or_diff_from_header(&diff_from_digests, args->headers)) { - tor_assert(diff_from_digests); - cached_diff = find_best_diff(diff_from_digests, flav, - args->compression_supported, - &compression_used); - SMARTLIST_FOREACH(diff_from_digests, uint8_t *, d, tor_free(d)); - smartlist_free(diff_from_digests); - } - conn->spool = smartlist_new(); clear_spool = 1; { spooled_resource_t *spooled; - if (cached_diff) { - spooled = spooled_resource_new_from_cache_entry(cached_diff); + if (cached_consensus) { + spooled = spooled_resource_new_from_cache_entry(cached_consensus); } else if (flavor) { spooled = spooled_resource_new(DIR_SPOOL_NETWORKSTATUS, (uint8_t*)flavor, strlen(flavor)); - compression_used = compress_method; + compression_used = ZLIB_METHOD; } else { spooled = spooled_resource_new(DIR_SPOOL_NETWORKSTATUS, NULL, 0); - compression_used = compress_method; + compression_used = ZLIB_METHOD; } tor_free(flavor); smartlist_add(conn->spool, spooled); } - lifetime = (v && v->fresh_until > now) ? v->fresh_until - now : 0; + + if (cached_consensus && + consensus_cache_entry_get_lifetime(cached_consensus, + &lifetime) != 0) { + lifetime = 0; + }
if (!smartlist_len(conn->spool)) { /* we failed to create/cache cp */ write_http_status_line(conn, 503, "Network status object unavailable"); @@ -3875,8 +3927,11 @@ handle_get_current_consensus(dir_connection_t *conn, write_http_response_header(conn, -1, compression_used, smartlist_len(conn->spool) == 1 ? lifetime : 0); - if (compress_method != NO_METHOD) - conn->compress_state = tor_compress_new(0, compress_method, + + // The compress_method requested was NO_METHOD, but we store the data + // compressed. Decompress them using `compression_used`. + if (compress_method == NO_METHOD) + conn->compress_state = tor_compress_new(0, compression_used, HIGH_COMPRESSION);
/* Prime the connection with some data. */