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author | delphij <delphij@FreeBSD.org> | 2016-11-22 16:22:51 +0000 |
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committer | delphij <delphij@FreeBSD.org> | 2016-11-22 16:22:51 +0000 |
commit | db75d5027e10e6a41b54cb66e21f2fe7480a1618 (patch) | |
tree | cbd2aa90bc18e76606f3844a0fe1f82777b5c967 /contrib/ntp/ntpd/refclock_jupiter.c | |
parent | 4188db2d72044b0a0307b91499f5de0f9b4d9a94 (diff) | |
download | FreeBSD-src-db75d5027e10e6a41b54cb66e21f2fe7480a1618.zip FreeBSD-src-db75d5027e10e6a41b54cb66e21f2fe7480a1618.tar.gz |
MFC r308957: MFV r308954:
ntp 4.2.8p9.
Approved by: so
Diffstat (limited to 'contrib/ntp/ntpd/refclock_jupiter.c')
-rw-r--r-- | contrib/ntp/ntpd/refclock_jupiter.c | 67 |
1 files changed, 66 insertions, 1 deletions
diff --git a/contrib/ntp/ntpd/refclock_jupiter.c b/contrib/ntp/ntpd/refclock_jupiter.c index 02b33df..84d089d 100644 --- a/contrib/ntp/ntpd/refclock_jupiter.c +++ b/contrib/ntp/ntpd/refclock_jupiter.c @@ -89,6 +89,11 @@ /* Unix timestamp for the GPS epoch: January 6, 1980 */ #define GPS_EPOCH 315964800 +/* Rata Die Number of first day of GPS epoch. This is the number of days + * since 0000-12-31 to 1980-01-06 in the proleptic Gregorian Calendar. + */ +#define RDN_GPS_EPOCH (4*146097 + 138431 + 1) + /* Double short to unsigned int */ #define DS2UI(p) ((getshort((p)[1]) << 16) | getshort((p)[0])) @@ -154,6 +159,10 @@ static char * jupiter_send (struct instance *, struct jheader *); static void jupiter_shutdown(int, struct peer *); static int jupiter_start (int, struct peer *); +static u_int get_full_week(u_int base_week, u_int gpos_week); +static u_int get_base_week(void); + + /* * Transfer vector */ @@ -846,8 +855,14 @@ jupiter_parse_gpos(struct instance *instance, u_short *sp) return ("Navigation solution not valid"); } - instance->gpos_gweek = jg->gweek; instance->gpos_sweek = DS2UI(jg->sweek); + instance->gpos_gweek = get_full_week(get_base_week(), + getshort(jg->gweek)); + + /* according to the protocol spec, the seconds-in-week cannot + * exceed the nominal value: Is it really necessary to normalise + * the seconds??? + */ while(instance->gpos_sweek >= WEEKSECS) { instance->gpos_sweek -= WEEKSECS; ++instance->gpos_gweek; @@ -1115,6 +1130,56 @@ jupiter_recv(struct instance *instance) return (cc); } +static u_int +get_base_week(void) +{ + static int init_done /* = 0 */; + static u_int base_week; + + /* Get the build date, convert to days since GPS epoch and + * finally weeks since GPS epoch. Note that the build stamp is + * trusted once it is fetched -- only dates before the GPS epoch + * are not permitted. This will permit proper synchronisation + * for a time range of 1024 weeks starting with 00:00:00 of the + * last Sunday on or before the build time. + * + * If the impossible happens and fetching the build date fails, + * a 1024-week cycle starting with 2016-01-03 is assumed to + * avoid catastropic errors. This will work until 2035-08-19. + */ + if (!init_done) { + struct calendar bd; + if (ntpcal_get_build_date(&bd)) { + int32_t days = ntpcal_date_to_rd(&bd); + if (days > RDN_GPS_EPOCH) + days -= RDN_GPS_EPOCH; + else + days = 0; + base_week = days / 7; + } else { + base_week = 1878; /* 2016-01-03, Sunday */ + msyslog(LOG_ERR, + "refclock_jupiter: ntpcal_get_build_date() failed: %s", + "using 2016-01-03 as GPS base!"); + } + init_done = 1; + } + return base_week; +} + +static u_int +get_full_week( + u_int base_week, + u_int gpos_week + ) +{ + /* Periodic extension on base week. Since the period is 1024 + * weeks and we do unsigned arithmetic here, we can do wonderful + * things with masks and the well-defined overflow behaviour. + */ + return base_week + ((gpos_week - base_week) & 1023); +} + #else /* not (REFCLOCK && CLOCK_JUPITER && HAVE_PPSAPI) */ int refclock_jupiter_bs; #endif /* not (REFCLOCK && CLOCK_JUPITER && HAVE_PPSAPI) */ |