commit 444e46d96d05c3e12eca02769512c74f2eb16b48 Author: Nick Mathewson nickm@torproject.org Date: Fri Mar 25 15:27:06 2011 -0400
Remove the "fuzzy time" code
It was the start of a neat idea, but it only got used in 3 places, none of which really needed it. --- changes/kill_ftime | 7 ++++ src/common/util.c | 77 ------------------------------------------------ src/common/util.h | 10 ------ src/or/networkstatus.c | 6 +++- src/or/routerlist.c | 4 +- 5 files changed, 14 insertions(+), 90 deletions(-)
diff --git a/changes/kill_ftime b/changes/kill_ftime new file mode 100644 index 0000000..47f4769 --- /dev/null +++ b/changes/kill_ftime @@ -0,0 +1,7 @@ + o Code simplification and refactoring + - Remove the old 'fuzzy time' logic. It was supposed to be used + for handling calculations where we have a known amount of clock + skew and an allowed amount of unknown skew. But we only used it + in three places, and we never adjusted the known/unknown skew + values. This is still something we might want to do someday, + but if we do, we'll want to do it differently. diff --git a/src/common/util.c b/src/common/util.c index abd87ea..38c0ad0 100644 --- a/src/common/util.c +++ b/src/common/util.c @@ -1511,83 +1511,6 @@ update_approx_time(time_t now) #endif
/* ===== - * Fuzzy time - * XXXX022 Use this consistently or rip most of it out. - * ===== */ - -/* In a perfect world, everybody would run NTP, and NTP would be perfect, so - * if we wanted to know "Is the current time before time X?" we could just say - * "time(NULL) < X". - * - * But unfortunately, many users are running Tor in an imperfect world, on - * even more imperfect computers. Hence, we need to track time oddly. We - * model the user's computer as being "skewed" from accurate time by - * -<b>ftime_skew</b> seconds, such that our best guess of the current time is - * time(NULL)+ftime_skew. We also assume that our measurements of time may - * have up to <b>ftime_slop</b> seconds of inaccuracy; IOW, our window of - * estimate for the current time is now + ftime_skew +/- ftime_slop. - */ -/** Our current estimate of our skew, such that we think the current time is - * closest to time(NULL)+ftime_skew. */ -static int ftime_skew = 0; -/** Tolerance during time comparisons, in seconds. */ -static int ftime_slop = 60; -/** Set the largest amount of sloppiness we'll allow in fuzzy time - * comparisons. */ -void -ftime_set_maximum_sloppiness(int seconds) -{ - tor_assert(seconds >= 0); - ftime_slop = seconds; -} -/** Set the amount by which we believe our system clock to differ from - * real time. */ -void -ftime_set_estimated_skew(int seconds) -{ - ftime_skew = seconds; -} -#if 0 -void -ftime_get_window(time_t now, ftime_t *ft_out) -{ - ft_out->earliest = now + ftime_skew - ftime_slop; - ft_out->latest = now + ftime_skew + ftime_slop; -} -#endif -/** Return true iff we think that <b>now</b> might be after <b>when</b>. */ -int -ftime_maybe_after(time_t now, time_t when) -{ - /* It may be after when iff the latest possible current time is after when */ - return (now + ftime_skew + ftime_slop) >= when; -} -/** Return true iff we think that <b>now</b> might be before <b>when</b>. */ -int -ftime_maybe_before(time_t now, time_t when) -{ - /* It may be before when iff the earliest possible current time is before */ - return (now + ftime_skew - ftime_slop) < when; -} -/** Return true if we think that <b>now</b> is definitely after <b>when</b>. */ -int -ftime_definitely_after(time_t now, time_t when) -{ - /* It is definitely after when if the earliest time it could be is still - * after when. */ - return (now + ftime_skew - ftime_slop) >= when; -} -/** Return true if we think that <b>now</b> is definitely before <b>when</b>. - */ -int -ftime_definitely_before(time_t now, time_t when) -{ - /* It is definitely before when if the latest time it could be is still - * before when. */ - return (now + ftime_skew + ftime_slop) < when; -} - -/* ===== * Rate limiting * ===== */
diff --git a/src/common/util.h b/src/common/util.h index 3736237..6b54856 100644 --- a/src/common/util.h +++ b/src/common/util.h @@ -247,16 +247,6 @@ time_t approx_time(void); void update_approx_time(time_t now); #endif
-/* Fuzzy time. */ -void ftime_set_maximum_sloppiness(int seconds); -void ftime_set_estimated_skew(int seconds); -/* typedef struct ftime_t { time_t earliest; time_t latest; } ftime_t; */ -/* void ftime_get_window(time_t now, ftime_t *ft_out); */ -int ftime_maybe_after(time_t now, time_t when); -int ftime_maybe_before(time_t now, time_t when); -int ftime_definitely_after(time_t now, time_t when); -int ftime_definitely_before(time_t now, time_t when); - /* Rate-limiter */
/** A ratelim_t remembers how often an event is occurring, and how often diff --git a/src/or/networkstatus.c b/src/or/networkstatus.c index 687ac03..155dffe 100644 --- a/src/or/networkstatus.c +++ b/src/or/networkstatus.c @@ -1764,7 +1764,11 @@ networkstatus_set_current_consensus(const char *consensus, write_str_to_file(consensus_fname, consensus, 0); }
- if (ftime_definitely_before(now, current_consensus->valid_after)) { +/** If a consensus appears more than this many seconds before its declared + * valid-after time, declare that our clock is skewed. */ +#define EARLY_CONSENSUS_NOTICE_SKEW 60 + + if (now < current_consensus->valid_after - EARLY_CONSENSUS_NOTICE_SKEW) { char tbuf[ISO_TIME_LEN+1]; char dbuf[64]; long delta = now - current_consensus->valid_after; diff --git a/src/or/routerlist.c b/src/or/routerlist.c index 4421d5c..2dca578 100644 --- a/src/or/routerlist.c +++ b/src/or/routerlist.c @@ -328,7 +328,7 @@ trusted_dirs_remove_old_certs(void) time_t cert_published; if (newest == cert) continue; - expired = ftime_definitely_after(now, cert->expires); + expired = now > cert->expires; cert_published = cert->cache_info.published_on; /* Store expired certs for 48 hours after a newer arrives; */ @@ -520,7 +520,7 @@ authority_certs_fetch_missing(networkstatus_t *status, time_t now) continue; cl = get_cert_list(ds->v3_identity_digest); SMARTLIST_FOREACH(cl->certs, authority_cert_t *, cert, { - if (!ftime_definitely_after(now, cert->expires)) { + if (now < cert->expires) { /* It's not expired, and we weren't looking for something to * verify a consensus with. Call it done. */ download_status_reset(&cl->dl_status);