diff options
Diffstat (limited to 'src/or/main.c')
| -rw-r--r-- | src/or/main.c | 43 |
1 files changed, 38 insertions, 5 deletions
diff --git a/src/or/main.c b/src/or/main.c index d773c8e29b..e82162c399 100644 --- a/src/or/main.c +++ b/src/or/main.c @@ -2498,6 +2498,8 @@ static int n_libevent_errors = 0; /** Last time that update_current_time was called. */ static time_t current_second = 0; +/** Last time that update_current_time updated current_second. */ +static monotime_coarse_t current_second_last_changed; /** * Set the current time to "now", which should be the value returned by @@ -2515,13 +2517,42 @@ update_current_time(time_t now) const time_t seconds_elapsed = current_second ? (now - current_second) : 0; -/** If more than this many seconds have elapsed, probably the clock - * jumped: doesn't count. */ + /* Check the wall clock against the monotonic clock, so we can + * better tell idleness from clock jumps and/or other shenanigans. */ + monotime_coarse_t last_updated; + memcpy(&last_updated, ¤t_second_last_changed, sizeof(last_updated)); + monotime_coarse_get(¤t_second_last_changed); + + /** How much clock jumping do we tolerate? */ #define NUM_JUMPED_SECONDS_BEFORE_WARN 100 - if (seconds_elapsed < -NUM_JUMPED_SECONDS_BEFORE_WARN || - seconds_elapsed >= NUM_JUMPED_SECONDS_BEFORE_WARN) { - circuit_note_clock_jumped(seconds_elapsed); + /** How much idleness do we tolerate? */ +#define NUM_IDLE_SECONDS_BEFORE_WARN 3600 + + if (seconds_elapsed < -NUM_JUMPED_SECONDS_BEFORE_WARN) { + // moving back in time is always a bad sign. + circuit_note_clock_jumped(seconds_elapsed, false); + } else if (seconds_elapsed >= NUM_JUMPED_SECONDS_BEFORE_WARN) { + /* Compare the monotonic clock to the result of time(). */ + const int32_t monotime_msec_passed = + monotime_coarse_diff_msec32(&last_updated, + ¤t_second_last_changed); + const int monotime_sec_passed = monotime_msec_passed / 1000; + const int discrepency = monotime_sec_passed - seconds_elapsed; + /* If the monotonic clock deviates from time(NULL), we have a couple of + * possibilities. On some systems, this means we have been suspended or + * sleeping. Everywhere, it can mean that the wall-clock time has + * been changed -- for example, with settimeofday(). + * + * On the other hand, if the monotonic time matches with the wall-clock + * time, we've probably just been idle for a while, with no events firing. + * we tolerate much more of that. + */ + const bool clock_jumped = abs(discrepency) > 2; + + if (clock_jumped || seconds_elapsed >= NUM_IDLE_SECONDS_BEFORE_WARN) { + circuit_note_clock_jumped(seconds_elapsed, ! clock_jumped); + } } else if (seconds_elapsed > 0) { stats_n_seconds_working += seconds_elapsed; } @@ -3686,6 +3717,8 @@ tor_free_all(int postfork) heartbeat_callback_first_time = 1; n_libevent_errors = 0; current_second = 0; + memset(¤t_second_last_changed, 0, + sizeof(current_second_last_changed)); if (!postfork) { release_lockfile(); |