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fix ts2phc to correctly handle leap seconds (RHEL-40216)

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Resolves: RHEL-40216
This commit is contained in:
Miroslav Lichvar 2024-06-12 14:01:08 +02:00
parent 16c65dd0fd
commit 341bd2c2cd
2 changed files with 78 additions and 0 deletions
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76
linuxptp-nmealeap.patch Normal file
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@ -0,0 +1,76 @@
commit f3c742e24a40cf75272ec39789a2cba35389230d
Author: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue Jun 11 15:25:54 2024 +0200
nmea: Fix conversion of leap second.
When a leap second is inserted, the RMC message reports time of
23:59:60, which overflows in mktime() to 0:00:00 after the leap second
with an incremented TAI-UTC offset. This causes a one-second error in
the offset meaured by ts2phc.
Check the seconds field of the RMC message and convert 60 to 59 to make
the timestamp ambiguous per is_utc_ambiguous() and ignored by ts2phc to
avoid updating the clock with the one-second error.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
diff --git a/nmea.c b/nmea.c
index 7f1d9a2..b84b42e 100644
--- a/nmea.c
+++ b/nmea.c
@@ -155,6 +155,9 @@ static int nmea_scan_rmc(struct nmea_parser *np, struct nmea_rmc *result)
if (cnt != 3) {
return -1;
}
+ /* Convert an inserted leap second to ambiguous 23:59:59 */
+ if (tm.tm_sec == 60)
+ tm.tm_sec = 59;
tm.tm_year += 100;
tm.tm_mon--;
tm.tm_isdst = 0;
commit b396d361b0d290ce83395851860c2dcd074e0f3b
Author: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue Jun 11 15:32:55 2024 +0200
ts2phc: Fix timestamp conversion for leap seconds.
The UTC timestamp parsed from the RMC message needs to be converted to
TAI in order to calculate the PHC offset. This conversion was done after
adjusting the timestamp for the measured delay between the reception of
the message and the following pulse, which caused the offset measured by
ts2phc to have a one-second error if the message expected during or
after a leap second was missed.
Apply the TAI-UTC offset to the timestamp parsed from the RMC message
before any adjustments are made to avoid the error.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
diff --git a/ts2phc_nmea_pps_source.c b/ts2phc_nmea_pps_source.c
index 7a28433..bdfaf19 100644
--- a/ts2phc_nmea_pps_source.c
+++ b/ts2phc_nmea_pps_source.c
@@ -186,10 +186,9 @@ static int ts2phc_nmea_pps_source_getppstime(struct ts2phc_pps_source *src,
pr_err("nmea: rmc time stamp stale");
return -1;
}
- rmc = tmv_add(rmc, duration_since_rmc);
+
utc_time = tmv_to_nanoseconds(rmc);
utc_time /= (int64_t) 1000000000;
- *ts = tmv_to_timespec(rmc);
result = lstab_utc2tai(m->lstab, utc_time, &tai_offset);
switch (result) {
@@ -206,6 +205,9 @@ static int ts2phc_nmea_pps_source_getppstime(struct ts2phc_pps_source *src,
pr_err("nmea: utc time stamp is ambiguous");
break;
}
+
+ rmc = tmv_add(rmc, duration_since_rmc);
+ *ts = tmv_to_timespec(rmc);
ts->tv_sec += tai_offset;
return lstab_error;

2
linuxptp.spec
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@ -33,6 +33,8 @@ Patch4: linuxptp-ucastrate.patch
Patch5: linuxptp-nmeadelay.patch
# fix loading and reloading of leapfile
Patch6: linuxptp-lstab.patch
# fix ts2phc to correctly handle leap seconds
Patch7: linuxptp-nmealeap.patch
# check for EL-specific kernels with vclock support
Patch12: linuxptp-vclock.patch