rephist.c

关于tor匿名通信的源代码

    total += (when - hist->start_of_downtime);
  }
  return total;
}

/** Helper: Return the weighted percent-of-time-online of the router with
 * history <b>hist</b>. */
static double
get_weighted_fractional_uptime(or_history_t *hist, time_t when)
{
  unsigned long total = hist->total_weighted_time;
  unsigned long up = hist->weighted_uptime;

  if (hist->start_of_run) {
    long run_length = (when - hist->start_of_run);
    up += run_length;
    total += run_length;
  } else if (hist->start_of_downtime) {
    total += (when - hist->start_of_downtime);
  }
  return ((double) up) / total;
}

/** Return an estimated MTBF for the router whose identity digest is
 * <b>id</b>. Return 0 if the router is unknown. */
double
rep_hist_get_stability(const char *id, time_t when)
{
  or_history_t *hist = get_or_history(id);
  if (!hist)
    return 0.0;

  return get_stability(hist, when);
}

/** Return an estimated percent-of-time-online for the router whose identity
 * digest is <b>id</b>. Return 0 if the router is unknown. */
double
rep_hist_get_weighted_fractional_uptime(const char *id, time_t when)
{
  or_history_t *hist = get_or_history(id);
  if (!hist)
    return 0.0;

  return get_weighted_fractional_uptime(hist, when);
}

/** Return a number representing how long we've known about the router whose
 * digest is <b>id</b>. Return 0 if the router is unknown.
 *
 * Be careful: this measure incresases monotonically as we know the router for
 * longer and longer, but it doesn't increase linearly.
 */
long
rep_hist_get_weighted_time_known(const char *id, time_t when)
{
  or_history_t *hist = get_or_history(id);
  if (!hist)
    return 0;

  return get_total_weighted_time(hist, when);
}

/** Return true if we've been measuring MTBFs for long enough to
 * pronounce on Stability. */
int
rep_hist_have_measured_enough_stability(void)
{
  /* XXXX021 This doesn't do so well when we change our opinion
   * as to whether we're tracking router stability. */
  return started_tracking_stability < time(NULL) - 4*60*60;
}

/** Remember that we successfully extended from the OR with identity
 * digest <b>from_id</b> to the OR with identity digest
 * <b>to_name</b>.
 */
void
rep_hist_note_extend_succeeded(const char *from_id, const char *to_id)
{
  link_history_t *hist;
  /* log_fn(LOG_WARN, "EXTEND SUCCEEDED: %s->%s",from_name,to_name); */
  hist = get_link_history(from_id, to_id);
  if (!hist)
    return;
  ++hist->n_extend_ok;
  hist->changed = time(NULL);
}

/** Remember that we tried to extend from the OR with identity digest
 * <b>from_id</b> to the OR with identity digest <b>to_name</b>, but
 * failed.
 */
void
rep_hist_note_extend_failed(const char *from_id, const char *to_id)
{
  link_history_t *hist;
  /* log_fn(LOG_WARN, "EXTEND FAILED: %s->%s",from_name,to_name); */
  hist = get_link_history(from_id, to_id);
  if (!hist)
    return;
  ++hist->n_extend_fail;
  hist->changed = time(NULL);
}

/** Log all the reliability data we have remembered, with the chosen
 * severity.
 */
void
rep_hist_dump_stats(time_t now, int severity)
{
  digestmap_iter_t *lhist_it;
  digestmap_iter_t *orhist_it;
  const char *name1, *name2, *digest1, *digest2;
  char hexdigest1[HEX_DIGEST_LEN+1];
  or_history_t *or_history;
  link_history_t *link_history;
  void *or_history_p, *link_history_p;
  double uptime;
  char buffer[2048];
  size_t len;
  int ret;
  unsigned long upt, downt;
  routerinfo_t *r;

  rep_history_clean(now - get_options()->RephistTrackTime);

  log(severity, LD_GENERAL, "--------------- Dumping history information:");

  for (orhist_it = digestmap_iter_init(history_map);
       !digestmap_iter_done(orhist_it);
       orhist_it = digestmap_iter_next(history_map,orhist_it)) {
    double s;
    long stability;
    digestmap_iter_get(orhist_it, &digest1, &or_history_p);
    or_history = (or_history_t*) or_history_p;

    if ((r = router_get_by_digest(digest1)))
      name1 = r->nickname;
    else
      name1 = "(unknown)";
    base16_encode(hexdigest1, sizeof(hexdigest1), digest1, DIGEST_LEN);
    update_or_history(or_history, now);
    upt = or_history->uptime;
    downt = or_history->downtime;
    s = get_stability(or_history, now);
    stability = (long)s;
    if (upt+downt) {
      uptime = ((double)upt) / (upt+downt);
    } else {
      uptime=1.0;
    }
    log(severity, LD_GENERAL,
        "OR %s [%s]: %ld/%ld good connections; uptime %ld/%ld sec (%.2f%%); "
        "wmtbf %lu:%02lu:%02lu",
        name1, hexdigest1,
        or_history->n_conn_ok, or_history->n_conn_fail+or_history->n_conn_ok,
        upt, upt+downt, uptime*100.0,
        stability/3600, (stability/60)%60, stability%60);

    if (!digestmap_isempty(or_history->link_history_map)) {
      strlcpy(buffer, "    Extend attempts: ", sizeof(buffer));
      len = strlen(buffer);
      for (lhist_it = digestmap_iter_init(or_history->link_history_map);
           !digestmap_iter_done(lhist_it);
           lhist_it = digestmap_iter_next(or_history->link_history_map,
                                          lhist_it)) {
        digestmap_iter_get(lhist_it, &digest2, &link_history_p);
        if ((r = router_get_by_digest(digest2)))
          name2 = r->nickname;
        else
          name2 = "(unknown)";

        link_history = (link_history_t*) link_history_p;

        ret = tor_snprintf(buffer+len, 2048-len, "%s(%ld/%ld); ", name2,
                        link_history->n_extend_ok,
                        link_history->n_extend_ok+link_history->n_extend_fail);
        if (ret<0)
          break;
        else
          len += ret;
      }
      log(severity, LD_GENERAL, "%s", buffer);
    }
  }
}

/** Remove history info for routers/links that haven't changed since
 * <b>before</b>.
 */
void
rep_history_clean(time_t before)
{
  int authority = authdir_mode(get_options());
  or_history_t *or_history;
  link_history_t *link_history;
  void *or_history_p, *link_history_p;
  digestmap_iter_t *orhist_it, *lhist_it;
  const char *d1, *d2;

  orhist_it = digestmap_iter_init(history_map);
  while (!digestmap_iter_done(orhist_it)) {
    int remove;
    digestmap_iter_get(orhist_it, &d1, &or_history_p);
    or_history = or_history_p;

    remove = authority ? (or_history->total_run_weights < STABILITY_EPSILON &&
                          !or_history->start_of_run)
                       : (or_history->changed < before);
    if (remove) {
      orhist_it = digestmap_iter_next_rmv(history_map, orhist_it);
      free_or_history(or_history);
      continue;
    }
    for (lhist_it = digestmap_iter_init(or_history->link_history_map);
         !digestmap_iter_done(lhist_it); ) {
      digestmap_iter_get(lhist_it, &d2, &link_history_p);
      link_history = link_history_p;
      if (link_history->changed < before) {
        lhist_it = digestmap_iter_next_rmv(or_history->link_history_map,
                                           lhist_it);
        rephist_total_alloc -= sizeof(link_history_t);
        tor_free(link_history);
        continue;
      }
      lhist_it = digestmap_iter_next(or_history->link_history_map,lhist_it);
    }
    orhist_it = digestmap_iter_next(history_map, orhist_it);
  }
}

/** Write MTBF data to disk.  Returns 0 on success, negative on failure. */
int
rep_hist_record_mtbf_data(void)
{
  char time_buf[ISO_TIME_LEN+1];

  digestmap_iter_t *orhist_it;
  const char *digest;
  void *or_history_p;
  or_history_t *hist;
  open_file_t *open_file = NULL;
  FILE *f;

  {
    char *filename = get_datadir_fname("router-stability");
    f = start_writing_to_stdio_file(filename, OPEN_FLAGS_REPLACE|O_TEXT, 0600,
                                    &open_file);
    tor_free(filename);
    if (!f)
      return -1;
  }

  /* File format is:
   *   FormatLine *KeywordLine Data
   *
   *   FormatLine = "format 1" NL
   *   KeywordLine = Keyword SP Arguments NL
   *   Data = "data" NL *RouterMTBFLine "." NL
   *   RouterMTBFLine = Fingerprint SP WeightedRunLen SP
   *           TotalRunWeights [SP S=StartRunTime] NL
   */
#define PUT(s) STMT_BEGIN if (fputs((s),f)<0) goto err; STMT_END
#define PRINTF(args) STMT_BEGIN if (fprintf args <0) goto err; STMT_END

  PUT("format 2\n");

  format_iso_time(time_buf, time(NULL));
  PRINTF((f, "stored-at %s\n", time_buf));

  if (started_tracking_stability) {
    format_iso_time(time_buf, started_tracking_stability);
    PRINTF((f, "tracked-since %s\n", time_buf));
  }
  if (stability_last_downrated) {
    format_iso_time(time_buf, stability_last_downrated);
    PRINTF((f, "last-downrated %s\n", time_buf));
  }

  PUT("data\n");

  /* XXX021 Nick: now bridge auths record this for all routers too.
   * Should we make them record it only for bridge routers? -RD
   * Not for 0.2.0. -NM */
  for (orhist_it = digestmap_iter_init(history_map);
       !digestmap_iter_done(orhist_it);
       orhist_it = digestmap_iter_next(history_map,orhist_it)) {
    char dbuf[HEX_DIGEST_LEN+1];
    const char *t = NULL;
    digestmap_iter_get(orhist_it, &digest, &or_history_p);
    hist = (or_history_t*) or_history_p;

    base16_encode(dbuf, sizeof(dbuf), digest, DIGEST_LEN);
    PRINTF((f, "R %s\n", dbuf));
    if (hist->start_of_run > 0) {
      format_iso_time(time_buf, hist->start_of_run);
      t = time_buf;
    }
    PRINTF((f, "+MTBF %lu %.5lf%s%s\n",
            hist->weighted_run_length, hist->total_run_weights,
            t ? " S=" : "", t ? t : ""));
    t = NULL;
    if (hist->start_of_downtime > 0) {
      format_iso_time(time_buf, hist->start_of_downtime);
      t = time_buf;
    }
    PRINTF((f, "+WFU %lu %lu%s%s\n",
            hist->weighted_uptime, hist->total_weighted_time,
            t ? " S=" : "", t ? t : ""));
  }

  PUT(".\n");

#undef PUT
#undef PRINTF

  return finish_writing_to_file(open_file);
 err:
  abort_writing_to_file(open_file);
  return -1;
}

/** Helper: return the first j >= i such that !strcmpstart(sl[j], prefix) and
 * such that no line sl[k] with i <= k < j starts with "R ".  Return -1 if no
 * such line exists. */
static int
find_next_with(smartlist_t *sl, int i, const char *prefix)
{
  for ( ; i < smartlist_len(sl); ++i) {
    const char *line = smartlist_get(sl, i);
    if (!strcmpstart(line, prefix))
      return i;
    if (!strcmpstart(line, "R "))
      return -1;
  }
  return -1;
}

/** How many bad times has parse_possibly_bad_iso_time parsed? */
static int n_bogus_times = 0;
/** Parse the ISO-formatted time in <b>s</b> into *<b>time_out</b>, but
 * rounds any pre-1970 date to Jan 1, 1970. */
static int
parse_possibly_bad_iso_time(const char *s, time_t *time_out)
{
  int year;
  char b[5];
  strlcpy(b, s, sizeof(b));
  b[4] = '\0';
  year = (int)tor_parse_long(b, 10, 0, INT_MAX, NULL, NULL);
  if (year < 1970) {
    *time_out = 0;
    ++n_bogus_times;
    return 0;
  } else
    return parse_iso_time(s, time_out);
}

/** We've read a time <b>t</b> from a file stored at <b>stored_at</b>, which
 * says we started measuring at <b>started_measuring</b>.  Return a new number
 * that's about as much before <b>now</b> as <b>t</b> was before
 * <b>stored_at</b>.
 */
static INLINE time_t
correct_time(time_t t, time_t now, time_t stored_at, time_t started_measuring)
{
  if (t < started_measuring - 24*60*60*365)
    return 0;
  else if (t < started_measuring)
    return started_measuring;
  else if (t > stored_at)
    return 0;
  else {
    long run_length = stored_at - t;
    t = now - run_length;
    if (t < started_measuring)
      t = started_measuring;
    return t;
  }
}

/** Load MTBF data from disk.  Returns 0 on success or recoverable error, -1
 * on failure. */
int
rep_hist_load_mtbf_data(time_t now)
{
  /* XXXX won't handle being called while history is already populated. */
  smartlist_t *lines;
  const char *line = NULL;
  int r=0, i;
  time_t last_downrated = 0, stored_at = 0, tracked_since = 0;
  time_t latest_possible_start = now;
  long format = -1;

  {
    char *filename = get_datadir_fname("router-stability");
    char *d = read_file_to_str(filename, RFTS_IGNORE_MISSING, NULL);
    tor_free(filename);
    if (!d)
      return -1;