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ntp: don't check reference timestamp in received packets

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When ntpd as an NTP server has active orphan mode, it doesn't update
its reference time and the reference timestamp may fail the NTP test
3 and 7. (https://bugs.ntp.org/show_bug.cgi?id=1098)

Remove both checks of the timestamp to allow chronyd to operate as
a client of ntpd server in the orphan mode. When ntpd is fixed and
old versions are no longer used, this may be reverted.
This commit is contained in:
Miroslav Lichvar 2016-04-01 14:24:04 +02:00
parent 6accd19eb3
commit 37e6357c02
1 changed files with 2 additions and 7 deletions
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9
ntp_core.c
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@ -1190,7 +1190,6 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
/* These are the timeval equivalents of the remote epochs */
struct timeval remote_receive_tv, remote_transmit_tv;
struct timeval remote_reference_tv;
struct timeval local_average, remote_average;
double local_interval, remote_interval;
@ -1229,7 +1228,6 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
UTI_Int64ToTimeval(&message->receive_ts, &remote_receive_tv);
UTI_Int64ToTimeval(&message->transmit_ts, &remote_transmit_tv);
UTI_Int64ToTimeval(&message->reference_ts, &remote_reference_tv);
/* Check if the packet is valid per RFC 5905, section 8.
The test values are 1 when passed and 0 when failed. */
@ -1247,7 +1245,6 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
association if not properly 'up'. */
test3 = (message->originate_ts.hi || message->originate_ts.lo) &&
(message->receive_ts.hi || message->receive_ts.lo) &&
(message->reference_ts.hi || message->reference_ts.lo) &&
(message->transmit_ts.hi || message->transmit_ts.lo);
/* Test 4 would check for denied access. It would always pass as this
@ -1268,10 +1265,8 @@ receive_packet(NTP_Packet *message, struct timeval *now, double now_err, NCR_Ins
message->stratum != NTP_INVALID_STRATUM;
/* Test 7 checks for bad data. The root distance must be smaller than a
defined maximum and the transmit time must not be before the time of
the last synchronisation update. */
test7 = pkt_root_delay / 2.0 + pkt_root_dispersion < NTP_MAX_DISPERSION &&
UTI_CompareTimevals(&remote_reference_tv, &remote_transmit_tv) < 1;
defined maximum. */
test7 = pkt_root_delay / 2.0 + pkt_root_dispersion < NTP_MAX_DISPERSION;
/* The packet is considered valid if the tests above passed */
valid_packet = test1 && test2 && test3 && test5 && test6 && test7;