rephist.c

关于tor匿名通信的源代码

    lines = smartlist_create();
    smartlist_split_string(lines, d, "\n", SPLIT_SKIP_SPACE, 0);
    tor_free(d);
  }

  {
    const char *firstline;
    if (smartlist_len(lines)>4) {
      firstline = smartlist_get(lines, 0);
      if (!strcmpstart(firstline, "format "))
        format = tor_parse_long(firstline+strlen("format "),
                                10, -1, LONG_MAX, NULL, NULL);
    }
  }
  if (format != 1 && format != 2) {
    log_warn(LD_GENERAL,
             "Unrecognized format in mtbf history file. Skipping.");
    goto err;
  }
  for (i = 1; i < smartlist_len(lines); ++i) {
    line = smartlist_get(lines, i);
    if (!strcmp(line, "data"))
      break;
    if (!strcmpstart(line, "last-downrated ")) {
      if (parse_iso_time(line+strlen("last-downrated "), &last_downrated)<0)
        log_warn(LD_GENERAL,"Couldn't parse downrate time in mtbf "
                 "history file.");
    }
    if (!strcmpstart(line, "stored-at ")) {
      if (parse_iso_time(line+strlen("stored-at "), &stored_at)<0)
        log_warn(LD_GENERAL,"Couldn't parse stored time in mtbf "
                 "history file.");
    }
    if (!strcmpstart(line, "tracked-since ")) {
      if (parse_iso_time(line+strlen("tracked-since "), &tracked_since)<0)
        log_warn(LD_GENERAL,"Couldn't parse started-tracking time in mtbf "
                 "history file.");
    }
  }
  if (last_downrated > now)
    last_downrated = now;
  if (tracked_since > now)
    tracked_since = now;

  if (!stored_at) {
    log_warn(LD_GENERAL, "No stored time recorded.");
    goto err;
  }

  if (line && !strcmp(line, "data"))
    ++i;

  n_bogus_times = 0;

  for (; i < smartlist_len(lines); ++i) {
    char digest[DIGEST_LEN];
    char hexbuf[HEX_DIGEST_LEN+1];
    char mtbf_timebuf[ISO_TIME_LEN+1];
    char wfu_timebuf[ISO_TIME_LEN+1];
    time_t start_of_run = 0;
    time_t start_of_downtime = 0;
    int have_mtbf = 0, have_wfu = 0;
    long wrl = 0;
    double trw = 0;
    long wt_uptime = 0, total_wt_time = 0;
    int n;
    or_history_t *hist;
    line = smartlist_get(lines, i);
    if (!strcmp(line, "."))
      break;

    mtbf_timebuf[0] = '\0';
    wfu_timebuf[0] = '\0';

    if (format == 1) {
      n = sscanf(line, "%40s %ld %lf S=%10s %8s",
                 hexbuf, &wrl, &trw, mtbf_timebuf, mtbf_timebuf+11);
      if (n != 3 && n != 5) {
        log_warn(LD_GENERAL, "Couldn't scan line %s", escaped(line));
        continue;
      }
      have_mtbf = 1;
    } else {
      // format == 2.
      int mtbf_idx, wfu_idx;
      if (strcmpstart(line, "R ") || strlen(line) < 2+HEX_DIGEST_LEN)
        continue;
      strlcpy(hexbuf, line+2, sizeof(hexbuf));
      mtbf_idx = find_next_with(lines, i+1, "+MTBF ");
      wfu_idx = find_next_with(lines, i+1, "+WFU ");
      if (mtbf_idx >= 0) {
        const char *mtbfline = smartlist_get(lines, mtbf_idx);
        n = sscanf(mtbfline, "+MTBF %lu %lf S=%10s %8s",
                   &wrl, &trw, mtbf_timebuf, mtbf_timebuf+11);
        if (n == 2 || n == 4) {
          have_mtbf = 1;
        } else {
          log_warn(LD_GENERAL, "Couldn't scan +MTBF line %s",
                   escaped(mtbfline));
        }
      }
      if (wfu_idx >= 0) {
        const char *wfuline = smartlist_get(lines, wfu_idx);
        n = sscanf(wfuline, "+WFU %lu %lu S=%10s %8s",
                   &wt_uptime, &total_wt_time,
                   wfu_timebuf, wfu_timebuf+11);
        if (n == 2 || n == 4) {
          have_wfu = 1;
        } else {
          log_warn(LD_GENERAL, "Couldn't scan +WFU line %s", escaped(wfuline));
        }
      }
      if (wfu_idx > i)
        i = wfu_idx;
      if (mtbf_idx > i)
        i = mtbf_idx;
    }
    if (base16_decode(digest, DIGEST_LEN, hexbuf, HEX_DIGEST_LEN) < 0) {
      log_warn(LD_GENERAL, "Couldn't hex string %s", escaped(hexbuf));
      continue;
    }
    hist = get_or_history(digest);
    if (!hist)
      continue;

    if (have_mtbf) {
      if (mtbf_timebuf[0]) {
        mtbf_timebuf[10] = ' ';
        if (parse_possibly_bad_iso_time(mtbf_timebuf, &start_of_run)<0)
          log_warn(LD_GENERAL, "Couldn't parse time %s",
                   escaped(mtbf_timebuf));
      }
      hist->start_of_run = correct_time(start_of_run, now, stored_at,
                                        tracked_since);
      if (hist->start_of_run < latest_possible_start + wrl)
        latest_possible_start = hist->start_of_run - wrl;

      hist->weighted_run_length = wrl;
      hist->total_run_weights = trw;
    }
    if (have_wfu) {
      if (wfu_timebuf[0]) {
        wfu_timebuf[10] = ' ';
        if (parse_possibly_bad_iso_time(wfu_timebuf, &start_of_downtime)<0)
          log_warn(LD_GENERAL, "Couldn't parse time %s", escaped(wfu_timebuf));
      }
    }
    hist->start_of_downtime = correct_time(start_of_downtime, now, stored_at,
                                           tracked_since);
    hist->weighted_uptime = wt_uptime;
    hist->total_weighted_time = total_wt_time;
  }
  if (strcmp(line, "."))
    log_warn(LD_GENERAL, "Truncated MTBF file.");

  if (tracked_since < 86400*365) /* Recover from insanely early value. */
    tracked_since = latest_possible_start;

  stability_last_downrated = last_downrated;
  started_tracking_stability = tracked_since;

  goto done;
 err:
  r = -1;
 done:
  SMARTLIST_FOREACH(lines, char *, cp, tor_free(cp));
  smartlist_free(lines);
  return r;
}

/** For how many seconds do we keep track of individual per-second bandwidth
 * totals? */
#define NUM_SECS_ROLLING_MEASURE 10
/** How large are the intervals for which we track and report bandwidth use? */
#define NUM_SECS_BW_SUM_INTERVAL (15*60)
/** How far in the past do we remember and publish bandwidth use? */
#define NUM_SECS_BW_SUM_IS_VALID (24*60*60)
/** How many bandwidth usage intervals do we remember? (derived) */
#define NUM_TOTALS (NUM_SECS_BW_SUM_IS_VALID/NUM_SECS_BW_SUM_INTERVAL)

/** Structure to track bandwidth use, and remember the maxima for a given
 * time period.
 */
typedef struct bw_array_t {
  /** Observation array: Total number of bytes transferred in each of the last
   * NUM_SECS_ROLLING_MEASURE seconds. This is used as a circular array. */
  uint64_t obs[NUM_SECS_ROLLING_MEASURE];
  int cur_obs_idx; /**< Current position in obs. */
  time_t cur_obs_time; /**< Time represented in obs[cur_obs_idx] */
  uint64_t total_obs; /**< Total for all members of obs except
                       * obs[cur_obs_idx] */
  uint64_t max_total; /**< Largest value that total_obs has taken on in the
                       * current period. */
  uint64_t total_in_period; /**< Total bytes transferred in the current
                             * period. */

  /** When does the next period begin? */
  time_t next_period;
  /** Where in 'maxima' should the maximum bandwidth usage for the current
   * period be stored? */
  int next_max_idx;
  /** How many values in maxima/totals have been set ever? */
  int num_maxes_set;
  /** Circular array of the maximum
   * bandwidth-per-NUM_SECS_ROLLING_MEASURE usage for the last
   * NUM_TOTALS periods */
  uint64_t maxima[NUM_TOTALS];
  /** Circular array of the total bandwidth usage for the last NUM_TOTALS
   * periods */
  uint64_t totals[NUM_TOTALS];
} bw_array_t;

/** Shift the current period of b forward by one. */
static void
commit_max(bw_array_t *b)
{
  /* Store total from current period. */
  b->totals[b->next_max_idx] = b->total_in_period;
  /* Store maximum from current period. */
  b->maxima[b->next_max_idx++] = b->max_total;
  /* Advance next_period and next_max_idx */
  b->next_period += NUM_SECS_BW_SUM_INTERVAL;
  if (b->next_max_idx == NUM_TOTALS)
    b->next_max_idx = 0;
  if (b->num_maxes_set < NUM_TOTALS)
    ++b->num_maxes_set;
  /* Reset max_total. */
  b->max_total = 0;
  /* Reset total_in_period. */
  b->total_in_period = 0;
}

/** Shift the current observation time of 'b' forward by one second. */
static INLINE void
advance_obs(bw_array_t *b)
{
  int nextidx;
  uint64_t total;

  /* Calculate the total bandwidth for the last NUM_SECS_ROLLING_MEASURE
   * seconds; adjust max_total as needed.*/
  total = b->total_obs + b->obs[b->cur_obs_idx];
  if (total > b->max_total)
    b->max_total = total;

  nextidx = b->cur_obs_idx+1;
  if (nextidx == NUM_SECS_ROLLING_MEASURE)
    nextidx = 0;

  b->total_obs = total - b->obs[nextidx];
  b->obs[nextidx]=0;
  b->cur_obs_idx = nextidx;

  if (++b->cur_obs_time >= b->next_period)
    commit_max(b);
}

/** Add <b>n</b> bytes to the number of bytes in <b>b</b> for second
 * <b>when</b>. */
static INLINE void
add_obs(bw_array_t *b, time_t when, uint64_t n)
{
  /* Don't record data in the past. */
  if (when<b->cur_obs_time)
    return;
  /* If we're currently adding observations for an earlier second than
   * 'when', advance b->cur_obs_time and b->cur_obs_idx by an
   * appropriate number of seconds, and do all the other housekeeping */
  while (when>b->cur_obs_time)
    advance_obs(b);

  b->obs[b->cur_obs_idx] += n;
  b->total_in_period += n;
}

/** Allocate, initialize, and return a new bw_array. */
static bw_array_t *
bw_array_new(void)
{
  bw_array_t *b;
  time_t start;
  b = tor_malloc_zero(sizeof(bw_array_t));
  rephist_total_alloc += sizeof(bw_array_t);
  start = time(NULL);
  b->cur_obs_time = start;
  b->next_period = start + NUM_SECS_BW_SUM_INTERVAL;
  return b;
}

static bw_array_t *read_array = NULL;
static bw_array_t *write_array = NULL;

/** Set up read_array and write_array. */
static void
bw_arrays_init(void)
{
  read_array = bw_array_new();
  write_array = bw_array_new();
}

/** We read <b>num_bytes</b> more bytes in second <b>when</b>.
 *
 * Add num_bytes to the current running total for <b>when</b>.
 *
 * <b>when</b> can go back to time, but it's safe to ignore calls
 * earlier than the latest <b>when</b> you've heard of.
 */
void
rep_hist_note_bytes_written(size_t num_bytes, time_t when)
{
/* Maybe a circular array for recent seconds, and step to a new point
 * every time a new second shows up. Or simpler is to just to have
 * a normal array and push down each item every second; it's short.
 */
/* When a new second has rolled over, compute the sum of the bytes we've
 * seen over when-1 to when-1-NUM_SECS_ROLLING_MEASURE, and stick it
 * somewhere. See rep_hist_bandwidth_assess() below.
 */
  add_obs(write_array, when, num_bytes);
}

/** We wrote <b>num_bytes</b> more bytes in second <b>when</b>.
 * (like rep_hist_note_bytes_written() above)
 */
void
rep_hist_note_bytes_read(size_t num_bytes, time_t when)
{
/* if we're smart, we can make this func and the one above share code */
  add_obs(read_array, when, num_bytes);
}

/** Helper: Return the largest value in b->maxima.  (This is equal to the
 * most bandwidth used in any NUM_SECS_ROLLING_MEASURE period for the last
 * NUM_SECS_BW_SUM_IS_VALID seconds.)
 */
static uint64_t
find_largest_max(bw_array_t *b)
{
  int i;
  uint64_t max;
  max=0;
  for (i=0; i<NUM_TOTALS; ++i) {
    if (b->maxima[i]>max)
      max = b->maxima[i];
  }
  return max;
}

/** Find the largest sums in the past NUM_SECS_BW_SUM_IS_VALID (roughly)
 * seconds. Find one sum for reading and one for writing. They don't have
 * to be at the same time.
 *
 * Return the smaller of these sums, divided by NUM_SECS_ROLLING_MEASURE.
 */
int
rep_hist_bandwidth_assess(void)
{
  uint64_t w,r;
  r = find_largest_max(read_array);
  w = find_largest_max(write_array);
  if (r>w)
    return (int)(U64_TO_DBL(w)/NUM_SECS_ROLLING_MEASURE);
  else
    return (int)(U64_TO_DBL(r)/NUM_SECS_ROLLING_MEASURE);
}

/** Print the bandwidth history of b (either read_array or write_array)
 * into the buffer pointed to by buf.  The format is simply comma
 * separated numbers, from oldest to newest.
 *
 * It returns the number of bytes written.
 */
static size_t
rep_hist_fill_bandwidth_history(char *buf, size_t len, bw_array_t *b)
{
  char *cp = buf;
  int i, n;
  or_options_t *options = get_options();
  uint64_t cutoff;

  if (b->num_maxes_set <= b->next_max_idx) {
    /* We haven't been through the circular array yet; time starts at i=0.*/
    i = 0;
  } else {
    /* We've been around the array at least once.  The next i to be
       overwritten is the oldest. */
    i = b->next_max_idx;
  }

  if (options->RelayBandwidthRate) {
    /* We don't want to report that we used more bandwidth than the max we're
     * willing to relay; otherwise everybody will know how much traffic
     * we used ourself. */
    cutoff = options->RelayBandwidthRate * NUM_SECS_BW_SUM_INTERVAL;
  } else {
    cutoff = UINT64_MAX;
  }

  for (n=0; n<b->num_maxes_set; ++n,++i) {
    uint64_t total;
    if (i >= NUM_TOTALS)