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- /* Copyright (c) 2018, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /**
- * \file dirvote_common.c
- * \brief This file contains functions that are from the directory authority
- * subsystem related to voting specifically but used by many part of
- * tor. The full feature is built as part of the dirauth module.
- **/
- #define DIRVOTE_COMMON_PRIVATE
- #include "dirvote_common.h"
- #include "or.h"
- #include "config.h"
- #include "networkstatus.h"
- /* =====
- * Vote scheduling
- * ===== */
- /** Set *<b>timing_out</b> to the intervals at which we would like to vote.
- * Note that these aren't the intervals we'll use to vote; they're the ones
- * that we'll vote to use. */
- void
- dirvote_get_preferred_voting_intervals(vote_timing_t *timing_out)
- {
- const or_options_t *options = get_options();
- tor_assert(timing_out);
- timing_out->vote_interval = options->V3AuthVotingInterval;
- timing_out->n_intervals_valid = options->V3AuthNIntervalsValid;
- timing_out->vote_delay = options->V3AuthVoteDelay;
- timing_out->dist_delay = options->V3AuthDistDelay;
- }
- /** Return the start of the next interval of size <b>interval</b> (in
- * seconds) after <b>now</b>, plus <b>offset</b>. Midnight always
- * starts a fresh interval, and if the last interval of a day would be
- * truncated to less than half its size, it is rolled into the
- * previous interval. */
- time_t
- dirvote_get_start_of_next_interval(time_t now, int interval, int offset)
- {
- struct tm tm;
- time_t midnight_today=0;
- time_t midnight_tomorrow;
- time_t next;
- tor_gmtime_r(&now, &tm);
- tm.tm_hour = 0;
- tm.tm_min = 0;
- tm.tm_sec = 0;
- if (tor_timegm(&tm, &midnight_today) < 0) {
- log_warn(LD_BUG, "Ran into an invalid time when trying to find midnight.");
- }
- midnight_tomorrow = midnight_today + (24*60*60);
- next = midnight_today + ((now-midnight_today)/interval + 1)*interval;
- /* Intervals never cross midnight. */
- if (next > midnight_tomorrow)
- next = midnight_tomorrow;
- /* If the interval would only last half as long as it's supposed to, then
- * skip over to the next day. */
- if (next + interval/2 > midnight_tomorrow)
- next = midnight_tomorrow;
- next += offset;
- if (next - interval > now)
- next -= interval;
- return next;
- }
- /* Populate and return a new voting_schedule_t that can be used to schedule
- * voting. The object is allocated on the heap and it's the responsibility of
- * the caller to free it. Can't fail. */
- static voting_schedule_t *
- get_voting_schedule(const or_options_t *options, time_t now, int severity)
- {
- int interval, vote_delay, dist_delay;
- time_t start;
- time_t end;
- networkstatus_t *consensus;
- voting_schedule_t *new_voting_schedule;
- new_voting_schedule = tor_malloc_zero(sizeof(voting_schedule_t));
- consensus = networkstatus_get_live_consensus(now);
- if (consensus) {
- interval = (int)( consensus->fresh_until - consensus->valid_after );
- vote_delay = consensus->vote_seconds;
- dist_delay = consensus->dist_seconds;
- } else {
- interval = options->TestingV3AuthInitialVotingInterval;
- vote_delay = options->TestingV3AuthInitialVoteDelay;
- dist_delay = options->TestingV3AuthInitialDistDelay;
- }
- tor_assert(interval > 0);
- if (vote_delay + dist_delay > interval/2)
- vote_delay = dist_delay = interval / 4;
- start = new_voting_schedule->interval_starts =
- dirvote_get_start_of_next_interval(now,interval,
- options->TestingV3AuthVotingStartOffset);
- end = dirvote_get_start_of_next_interval(start+1, interval,
- options->TestingV3AuthVotingStartOffset);
- tor_assert(end > start);
- new_voting_schedule->fetch_missing_signatures = start - (dist_delay/2);
- new_voting_schedule->voting_ends = start - dist_delay;
- new_voting_schedule->fetch_missing_votes =
- start - dist_delay - (vote_delay/2);
- new_voting_schedule->voting_starts = start - dist_delay - vote_delay;
- {
- char tbuf[ISO_TIME_LEN+1];
- format_iso_time(tbuf, new_voting_schedule->interval_starts);
- tor_log(severity, LD_DIR,"Choosing expected valid-after time as %s: "
- "consensus_set=%d, interval=%d",
- tbuf, consensus?1:0, interval);
- }
- return new_voting_schedule;
- }
- #define voting_schedule_free(s) \
- FREE_AND_NULL(voting_schedule_t, voting_schedule_free_, (s))
- /** Frees a voting_schedule_t. This should be used instead of the generic
- * tor_free. */
- static void
- voting_schedule_free_(voting_schedule_t *voting_schedule_to_free)
- {
- if (!voting_schedule_to_free)
- return;
- tor_free(voting_schedule_to_free);
- }
- voting_schedule_t voting_schedule;
- /* Using the time <b>now</b>, return the next voting valid-after time. */
- time_t
- dirvote_get_next_valid_after_time(void)
- {
- /* This is a safe guard in order to make sure that the voting schedule
- * static object is at least initialized. Using this function with a zeroed
- * voting schedule can lead to bugs. */
- if (tor_mem_is_zero((const char *) &voting_schedule,
- sizeof(voting_schedule))) {
- dirvote_recalculate_timing(get_options(), time(NULL));
- voting_schedule.created_on_demand = 1;
- }
- return voting_schedule.interval_starts;
- }
- /** Set voting_schedule to hold the timing for the next vote we should be
- * doing. All type of tor do that because HS subsystem needs the timing as
- * well to function properly. */
- void
- dirvote_recalculate_timing(const or_options_t *options, time_t now)
- {
- voting_schedule_t *new_voting_schedule;
- /* get the new voting schedule */
- new_voting_schedule = get_voting_schedule(options, now, LOG_INFO);
- tor_assert(new_voting_schedule);
- /* Fill in the global static struct now */
- memcpy(&voting_schedule, new_voting_schedule, sizeof(voting_schedule));
- voting_schedule_free(new_voting_schedule);
- }
- /** Return the signature made by <b>voter</b> using the algorithm
- * <b>alg</b>, or NULL if none is found. */
- document_signature_t *
- dirvote_get_voter_sig_by_alg(const networkstatus_voter_info_t *voter,
- digest_algorithm_t alg)
- {
- if (!voter->sigs)
- return NULL;
- SMARTLIST_FOREACH(voter->sigs, document_signature_t *, sig,
- if (sig->alg == alg)
- return sig);
- return NULL;
- }
- /* =====
- * Certificate functions
- * ===== */
- /** Allocate and return a new authority_cert_t with the same contents as
- * <b>cert</b>. */
- authority_cert_t *
- dirvote_authority_cert_dup(authority_cert_t *cert)
- {
- authority_cert_t *out = tor_malloc(sizeof(authority_cert_t));
- tor_assert(cert);
- memcpy(out, cert, sizeof(authority_cert_t));
- /* Now copy pointed-to things. */
- out->cache_info.signed_descriptor_body =
- tor_strndup(cert->cache_info.signed_descriptor_body,
- cert->cache_info.signed_descriptor_len);
- out->cache_info.saved_location = SAVED_NOWHERE;
- out->identity_key = crypto_pk_dup_key(cert->identity_key);
- out->signing_key = crypto_pk_dup_key(cert->signing_key);
- return out;
- }
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