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Ignore measurements around leap second

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When current time is within 5 seconds of a leap second, don't accumulate
new samples or update the leap second status to increase the chances of
getting through safely.
This commit is contained in:
Miroslav Lichvar 2014-09-09 16:57:15 +02:00
parent e1accce498
commit 0e786f5907
3 changed files with 35 additions and 1 deletions
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27
reference.c
View file

@ -680,7 +680,7 @@ update_leap_status(NTP_Leap leap, time_t now)
}
}
if (leap_sec != our_leap_sec) {
if (leap_sec != our_leap_sec && !REF_IsLeapSecondClose()) {
LCL_SetLeap(leap_sec);
our_leap_sec = leap_sec;
}
@ -1150,6 +1150,31 @@ REF_IsLocalActive(void)
/* ================================================== */
#define LEAP_SECOND_CLOSE 5
int REF_IsLeapSecondClose(void)
{
struct timeval now, now_raw;
time_t t;
if (!our_leap_sec)
return 0;
SCH_GetLastEventTime(&now, NULL, &now_raw);
t = now.tv_sec > 0 ? now.tv_sec : -now.tv_sec;
if ((t + LEAP_SECOND_CLOSE) % (24 * 3600) < 2 * LEAP_SECOND_CLOSE)
return 1;
t = now_raw.tv_sec > 0 ? now_raw.tv_sec : -now_raw.tv_sec;
if ((t + LEAP_SECOND_CLOSE) % (24 * 3600) < 2 * LEAP_SECOND_CLOSE)
return 1;
return 0;
}
/* ================================================== */
void
REF_GetTrackingReport(RPT_TrackingReport *rep)
{

4
reference.h
View file

@ -161,6 +161,10 @@ extern void REF_EnableLocal(int stratum);
extern void REF_DisableLocal(void);
extern int REF_IsLocalActive(void);
/* Check if current raw or cooked time is close to a leap second
and is better to discard any measurements */
extern int REF_IsLeapSecondClose(void);
extern void REF_GetTrackingReport(RPT_TrackingReport *rep);
#endif /* GOT_REFERENCE_H */

5
sources.c
View file

@ -312,6 +312,11 @@ void SRC_AccumulateSample
DEBUG_LOG(LOGF_Sources, "ip=[%s] t=%s ofs=%f del=%f disp=%f str=%d",
source_to_string(inst), UTI_TimevalToString(sample_time), -offset, root_delay, root_dispersion, stratum);
if (REF_IsLeapSecondClose()) {
LOG(LOGS_INFO, LOGF_Sources, "Dropping sample around leap second");
return;
}
/* WE HAVE TO NEGATE OFFSET IN THIS CALL, IT IS HERE THAT THE SENSE OF OFFSET
IS FLIPPED */
SST_AccumulateSample(inst->stats, sample_time, -offset, peer_delay, peer_dispersion, root_delay, root_dispersion, stratum);