Rename dirvote_common.{c|h} to voting_schedule.{c|h}

No code behavior change.

Part of #25988

Signed-off-by: David Goulet <dgoulet@torproject.org>

1 files changed, 165 insertions, 0 deletions

diff --git a/src/or/voting_schedule.c b/src/or/voting_schedule.c
new file mode 100644
index 0000000000..9725a32737
--- /dev/null
+++ b/src/or/voting_schedule.c
@@ -0,0 +1,165 @@
+/* Copyright (c) 2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file voting_schedule.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 VOTING_SCHEDULE_PRIVATE
+#include "voting_schedule.h"
+
+#include "or.h"
+#include "config.h"
+#include "networkstatus.h"
+
+/* =====
+ * Vote scheduling
+ * ===== */
+
+/** 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);
+}
+