/*
** set_time applies 'offset' to the local clock.
*/
int
set_time(
double offset
)
{
int rc;
if (time_adjusted)
return EX_OK;
/*
** If we can step but we cannot slew, then step.
** If we can step or slew and and |offset| > steplimit, then step.
*/
if (ENABLED_OPT(STEP) &&
( !ENABLED_OPT(SLEW)
|| (ENABLED_OPT(SLEW) && (fabs(offset) > steplimit))
)) {
rc = step_systime(offset);
/* If there was a problem, can we rely on errno? */
if (1 == rc)
time_adjusted = TRUE;
return (time_adjusted)
? EX_OK
: 1;
/*
** In case of error, what should we use?
** EX_UNAVAILABLE?
** EX_OSERR?
** EX_NOPERM?
*/
}
if (ENABLED_OPT(SLEW)) {
rc = adj_systime(offset);
/* If there was a problem, can we rely on errno? */
if (1 == rc)
time_adjusted = TRUE;
return (time_adjusted)
? EX_OK
: 1;
/*
** In case of error, what should we use?
** EX_UNAVAILABLE?
** EX_OSERR?
** EX_NOPERM?
*/
}
return EX_SOFTWARE;
}
/*
* timer - event timer
*/
void
timer(void)
{
register struct peer *peer, *next_peer;
u_int n;
long delta;
/*
* The basic timerevent is one second. This is used to adjust
* the system clock in time and frequency, implement the
* kiss-o'-deatch function and implement the association
* polling function..
*/
current_time += nap_time;
get_systime(&sys_time);
nap_time = (u_long)-1;
if (do_adjtime) {
if (adjust_timer <= current_time) {
adjust_timer += 1;
adj_host_clock();
#ifdef REFCLOCK
for (n = 0; n < NTP_HASH_SIZE; n++) {
for (peer = peer_hash[n]; peer != 0; peer = next_peer) {
next_peer = peer->next;
if (peer->flags & FLAG_REFCLOCK)
refclock_timer(peer);
}
}
#endif /* REFCLOCK */
}
nap_time = 1;
}
if (awake_timer) {
if (awake_timer <= current_time) {
for (n = 0; n < NTP_HASH_SIZE; n++) {
for (peer = peer_hash[n]; peer != 0; peer = peer->next) {
peer->burst = NSTAGE;
peer->nextdate = current_time;
peer->throttle = 0;
}
}
allow_panic = TRUE; /* Allow for large time offsets */
init_loopfilter();
state = EVNT_NSET;
awake_timer = 0;
} else {
delta = awake_timer - current_time;
if (delta < nap_time) {
nap_time = delta;
}
}
}
/*
* Now dispatch any peers whose event timer has expired. Be
* careful here, since the peer structure might go away as the
* result of the call.
*/
for (n = 0; n < NTP_HASH_SIZE; n++) {
for (peer = peer_hash[n]; peer != 0; peer = next_peer) {
next_peer = peer->next;
if (peer->action && peer->nextaction <= current_time)
peer->action(peer);
/*
* Restrain the non-burst packet rate not more
* than one packet every 16 seconds. This is
* usually tripped using iburst and minpoll of
* 128 s or less.
*/
if (peer->throttle > 0)
peer->throttle--;
if (peer->nextdate <= current_time) {
#ifdef REFCLOCK
if (peer->flags & FLAG_REFCLOCK)
refclock_transmit(peer);
else
transmit(peer);
#else /* REFCLOCK */
transmit(peer);
#endif /* REFCLOCK */
}
if (peer->action && peer->nextaction >= current_time) {
delta = peer->nextaction - current_time;
if (delta < nap_time) {
nap_time = delta;
}
} else if (peer->nextdate >= current_time) {
delta = peer->nextdate - current_time;
if (delta < nap_time) {
nap_time = delta;
}
}
}
}
/*
* Orphan mode is active when enabled and when no servers less
* than the orphan statum are available. A server with no other
* synchronization source is an orphan It shows offset zero and
* reference ID the loopback address.
*/
if (sys_orphan < STRATUM_UNSPEC && sys_peer == NULL) {
if (sys_leap == LEAP_NOTINSYNC) {
sys_leap = LEAP_NOWARNING;
#ifdef OPENSSL
if (crypto_flags)
crypto_update();
#endif /* OPENSSL */
}
sys_stratum = (u_char)sys_orphan;
if (sys_stratum > 1)
sys_refid = htonl(LOOPBACKADR);
else
memcpy(&sys_refid, "LOOP", 4);
sys_offset = 0;
sys_rootdelay = 0;
sys_rootdisp = 0;
}
/*
* Leapseconds. If a leap is pending, decrement the time
* remaining. If less than one day remains, set the leap bits.
* When no time remains, clear the leap bits and increment the
* TAI. If kernel suppport is not available, do the leap
* crudely. Note a leap cannot be pending unless the clock is
* set.
*/
if (leapsec > 0) {
leapsec--;
if (leapsec == 0) {
sys_leap = LEAP_NOWARNING;
sys_tai = leap_tai;
#ifdef KERNEL_PLL
if (!(pll_control && kern_enable))
step_systime(-1.0);
#else /* KERNEL_PLL */
#ifndef SYS_WINNT /* WinNT port has its own leap second handling */
step_systime(-1.0);
#endif /* SYS_WINNT */
#endif /* KERNEL_PLL */
report_event(EVNT_LEAP, NULL, NULL);
} else {
if (leapsec < DAY)
sys_leap = LEAP_ADDSECOND;
if (leap_tai > 0)
sys_tai = leap_tai - 1;
}
}
/*
* Update huff-n'-puff filter.
*/
if (huffpuff_timer <= current_time) {
huffpuff_timer += HUFFPUFF;
huffpuff();
}
if (huffpuff_timer >= current_time) {
delta = huffpuff_timer - current_time;
if (delta < nap_time) {
nap_time = delta;
}
}
#ifdef OPENSSL
/*
* Garbage collect expired keys.
*/
if (keys_timer <= current_time) {
keys_timer += 1 << sys_automax;
auth_agekeys();
}
if (keys_timer >= current_time) {
delta = keys_timer - current_time;
if (delta < nap_time) {
nap_time = delta;
}
}
/*
* Garbage collect key list and generate new private value. The
* timer runs only after initial synchronization and fires about
* once per day.
*/
if (revoke_timer <= current_time && sys_leap !=
LEAP_NOTINSYNC) {
revoke_timer += 1 << sys_revoke;
RAND_bytes((u_char *)&sys_private, 4);
}
if (revoke_timer >= current_time) {
delta = revoke_timer - current_time;
if (delta < nap_time) {
nap_time = delta;
}
}
#endif /* OPENSSL */
/*
* Interface update timer
*/
if (interface_interval && interface_timer <= current_time) {
timer_interfacetimeout(current_time +
interface_interval);
DPRINTF(2, ("timer: interface update\n"));
interface_update(NULL, NULL);
}
if (interface_interval && interface_timer >= current_time) {
delta = interface_timer - current_time;
if (delta < nap_time) {
nap_time = delta;
}
}
if (dns_timer && (dns_timer <= current_time)) {
dns_timer = update_dns_peers();
}
if (dns_timer >= current_time) {
delta = dns_timer - current_time;
if (delta < nap_time) {
nap_time = delta;
}
}
/*
* Finally, write hourly stats.
*/
if (stats_timer <= current_time) {
stats_timer += HOUR;
write_stats();
if (sys_tai != 0 && sys_time.l_ui > leap_expire)
report_event(EVNT_LEAPVAL, NULL, NULL);
} else if (!do_adjtime && drift_file_sw) {
write_stats(); /* update more frequently for pacemaker */
}
if (stats_timer >= current_time) {
delta = stats_timer - current_time;
if (delta < nap_time) {
nap_time = delta;
}
}
if (nap_time == 0) {
nap_time = 1;
}
if (debug) {
msyslog(LOG_INFO, "%s: current_time: %ld, nap_time: %ld", __FUNCTION__,
current_time, nap_time);
}
itimer.it_interval.tv_sec = itimer.it_value.tv_sec = nap_time;
setitimer(ITIMER_REAL, &itimer, (struct itimerval *)0);
}
/*
* local_clock - the NTP logical clock loop filter.
*
* Return codes:
* -1 update ignored: exceeds panic threshold
* 0 update ignored: popcorn or exceeds step threshold
* 1 clock was slewed
* 2 clock was stepped
*
* LOCKCLOCK: The only thing this routine does is set the
* sys_rootdisp variable equal to the peer dispersion.
*/
int
local_clock(
struct peer *peer, /* synch source peer structure */
double fp_offset /* clock offset (s) */
)
{
int rval; /* return code */
int osys_poll; /* old system poll */
int ntp_adj_ret; /* returned by ntp_adjtime */
double mu; /* interval since last update */
double clock_frequency; /* clock frequency */
double dtemp, etemp; /* double temps */
char tbuf[80]; /* report buffer */
/*
* If the loop is opened or the NIST LOCKCLOCK is in use,
* monitor and record the offsets anyway in order to determine
* the open-loop response and then go home.
*/
#ifdef LOCKCLOCK
{
#else
if (!ntp_enable) {
#endif /* LOCKCLOCK */
record_loop_stats(fp_offset, drift_comp, clock_jitter,
clock_stability, sys_poll);
return (0);
}
#ifndef LOCKCLOCK
/*
* If the clock is way off, panic is declared. The clock_panic
* defaults to 1000 s; if set to zero, the panic will never
* occur. The allow_panic defaults to FALSE, so the first panic
* will exit. It can be set TRUE by a command line option, in
* which case the clock will be set anyway and time marches on.
* But, allow_panic will be set FALSE when the update is less
* than the step threshold; so, subsequent panics will exit.
*/
if (fabs(fp_offset) > clock_panic && clock_panic > 0 &&
!allow_panic) {
snprintf(tbuf, sizeof(tbuf),
"%+.0f s; set clock manually within %.0f s.",
fp_offset, clock_panic);
report_event(EVNT_SYSFAULT, NULL, tbuf);
return (-1);
}
/*
* This section simulates ntpdate. If the offset exceeds the
* step threshold (128 ms), step the clock to that time and
* exit. Otherwise, slew the clock to that time and exit. Note
* that the slew will persist and eventually complete beyond the
* life of this program. Note that while ntpdate is active, the
* terminal does not detach, so the termination message prints
* directly to the terminal.
*/
if (mode_ntpdate) {
if ( ( fp_offset > clock_max_fwd && clock_max_fwd > 0)
|| (-fp_offset > clock_max_back && clock_max_back > 0)) {
step_systime(fp_offset);
msyslog(LOG_NOTICE, "ntpd: time set %+.6f s",
fp_offset);
printf("ntpd: time set %+.6fs\n", fp_offset);
} else {
adj_systime(fp_offset);
msyslog(LOG_NOTICE, "ntpd: time slew %+.6f s",
fp_offset);
printf("ntpd: time slew %+.6fs\n", fp_offset);
}
record_loop_stats(fp_offset, drift_comp, clock_jitter,
clock_stability, sys_poll);
exit (0);
}
/*
* The huff-n'-puff filter finds the lowest delay in the recent
* interval. This is used to correct the offset by one-half the
* difference between the sample delay and minimum delay. This
* is most effective if the delays are highly assymetric and
* clockhopping is avoided and the clock frequency wander is
* relatively small.
*/
if (sys_huffpuff != NULL) {
if (peer->delay < sys_huffpuff[sys_huffptr])
sys_huffpuff[sys_huffptr] = peer->delay;
if (peer->delay < sys_mindly)
sys_mindly = peer->delay;
if (fp_offset > 0)
dtemp = -(peer->delay - sys_mindly) / 2;
else
dtemp = (peer->delay - sys_mindly) / 2;
fp_offset += dtemp;
#ifdef DEBUG
if (debug)
printf(
"local_clock: size %d mindly %.6f huffpuff %.6f\n",
sys_hufflen, sys_mindly, dtemp);
#endif
}
/*
* Clock state machine transition function which defines how the
* system reacts to large phase and frequency excursion. There
* are two main regimes: when the offset exceeds the step
* threshold (128 ms) and when it does not. Under certain
* conditions updates are suspended until the stepout theshold
* (900 s) is exceeded. See the documentation on how these
* thresholds interact with commands and command line options.
*
* Note the kernel is disabled if step is disabled or greater
* than 0.5 s or in ntpdate mode.
*/
osys_poll = sys_poll;
if (sys_poll < peer->minpoll)
sys_poll = peer->minpoll;
if (sys_poll > peer->maxpoll)
sys_poll = peer->maxpoll;
mu = current_time - clock_epoch;
clock_frequency = drift_comp;
rval = 1;
if ( ( fp_offset > clock_max_fwd && clock_max_fwd > 0)
|| (-fp_offset > clock_max_back && clock_max_back > 0)
|| force_step_once ) {
if (force_step_once) {
force_step_once = FALSE; /* we want this only once after startup */
msyslog(LOG_NOTICE, "Doing intital time step" );
}
switch (state) {
/*
* In SYNC state we ignore the first outlyer and switch
* to SPIK state.
*/
case EVNT_SYNC:
snprintf(tbuf, sizeof(tbuf), "%+.6f s",
fp_offset);
report_event(EVNT_SPIK, NULL, tbuf);
state = EVNT_SPIK;
return (0);
/*
* In FREQ state we ignore outlyers and inlyers. At the
* first outlyer after the stepout threshold, compute
* the apparent frequency correction and step the phase.
*/
case EVNT_FREQ:
if (mu < clock_minstep)
return (0);
clock_frequency = direct_freq(fp_offset);
/* fall through to EVNT_SPIK */
/*
* In SPIK state we ignore succeeding outlyers until
* either an inlyer is found or the stepout threshold is
* exceeded.
*/
case EVNT_SPIK:
if (mu < clock_minstep)
return (0);
/* fall through to default */
/*
* We get here by default in NSET and FSET states and
* from above in FREQ or SPIK states.
*
* In NSET state an initial frequency correction is not
* available, usually because the frequency file has not
* yet been written. Since the time is outside the step
* threshold, the clock is stepped. The frequency will
* be set directly following the stepout interval.
*
* In FSET state the initial frequency has been set from
* the frequency file. Since the time is outside the
* step threshold, the clock is stepped immediately,
* rather than after the stepout interval. Guys get
* nervous if it takes 15 minutes to set the clock for
* the first time.
*
* In FREQ and SPIK states the stepout threshold has
* expired and the phase is still above the step
* threshold. Note that a single spike greater than the
* step threshold is always suppressed, even with a
* long time constant.
*/
default:
snprintf(tbuf, sizeof(tbuf), "%+.6f s",
fp_offset);
report_event(EVNT_CLOCKRESET, NULL, tbuf);
step_systime(fp_offset);
reinit_timer();
tc_counter = 0;
clock_jitter = LOGTOD(sys_precision);
rval = 2;
if (state == EVNT_NSET) {
rstclock(EVNT_FREQ, 0);
return (rval);
}
break;
}
rstclock(EVNT_SYNC, 0);
} else {
/*
* The offset is less than the step threshold. Calculate
* the jitter as the exponentially weighted offset
* differences.
*/
etemp = SQUARE(clock_jitter);
dtemp = SQUARE(max(fabs(fp_offset - last_offset),
LOGTOD(sys_precision)));
clock_jitter = SQRT(etemp + (dtemp - etemp) /
CLOCK_AVG);
switch (state) {
/*
* In NSET state this is the first update received and
* the frequency has not been initialized. Adjust the
* phase, but do not adjust the frequency until after
* the stepout threshold.
*/
case EVNT_NSET:
adj_systime(fp_offset);
rstclock(EVNT_FREQ, fp_offset);
break;
/*
* In FREQ state ignore updates until the stepout
* threshold. After that, compute the new frequency, but
* do not adjust the frequency until the holdoff counter
* decrements to zero.
*/
case EVNT_FREQ:
if (mu < clock_minstep)
return (0);
clock_frequency = direct_freq(fp_offset);
/* fall through */
/*
* We get here by default in FSET, SPIK and SYNC states.
* Here compute the frequency update due to PLL and FLL
* contributions. Note, we avoid frequency discipline at
* startup until the initial transient has subsided.
*/
default:
allow_panic = FALSE;
if (freq_cnt == 0) {
/*
* The FLL and PLL frequency gain constants
* depend on the time constant and Allan
* intercept. The PLL is always used, but
* becomes ineffective above the Allan intercept
* where the FLL becomes effective.
*/
if (sys_poll >= allan_xpt)
clock_frequency += (fp_offset -
clock_offset) / max(ULOGTOD(sys_poll),
mu) * CLOCK_FLL;
/*
* The PLL frequency gain (numerator) depends on
* the minimum of the update interval and Allan
* intercept. This reduces the PLL gain when the
* FLL becomes effective.
*/
etemp = min(ULOGTOD(allan_xpt), mu);
dtemp = 4 * CLOCK_PLL * ULOGTOD(sys_poll);
clock_frequency += fp_offset * etemp / (dtemp *
dtemp);
}
rstclock(EVNT_SYNC, fp_offset);
if (fabs(fp_offset) < CLOCK_FLOOR)
freq_cnt = 0;
break;
}
}
#ifdef KERNEL_PLL
/*
* This code segment works when clock adjustments are made using
* precision time kernel support and the ntp_adjtime() system
* call. This support is available in Solaris 2.6 and later,
* Digital Unix 4.0 and later, FreeBSD, Linux and specially
* modified kernels for HP-UX 9 and Ultrix 4. In the case of the
* DECstation 5000/240 and Alpha AXP, additional kernel
* modifications provide a true microsecond clock and nanosecond
* clock, respectively.
*
* Important note: The kernel discipline is used only if the
* step threshold is less than 0.5 s, as anything higher can
* lead to overflow problems. This might occur if some misguided
* lad set the step threshold to something ridiculous.
*/
if (pll_control && kern_enable && freq_cnt == 0) {
/*
* We initialize the structure for the ntp_adjtime()
* system call. We have to convert everything to
* microseconds or nanoseconds first. Do not update the
* system variables if the ext_enable flag is set. In
* this case, the external clock driver will update the
* variables, which will be read later by the local
* clock driver. Afterwards, remember the time and
* frequency offsets for jitter and stability values and
* to update the frequency file.
*/
ZERO(ntv);
if (ext_enable) {
ntv.modes = MOD_STATUS;
} else {
#ifdef STA_NANO
ntv.modes = MOD_BITS | MOD_NANO;
#else /* STA_NANO */
ntv.modes = MOD_BITS;
#endif /* STA_NANO */
if (clock_offset < 0)
dtemp = -.5;
else
dtemp = .5;
#ifdef STA_NANO
ntv.offset = (int32)(clock_offset * 1e9 +
dtemp);
ntv.constant = sys_poll;
#else /* STA_NANO */
ntv.offset = (int32)(clock_offset * 1e6 +
dtemp);
ntv.constant = sys_poll - 4;
#endif /* STA_NANO */
if (ntv.constant < 0)
ntv.constant = 0;
ntv.esterror = (u_int32)(clock_jitter * 1e6);
ntv.maxerror = (u_int32)((sys_rootdelay / 2 +
sys_rootdisp) * 1e6);
ntv.status = STA_PLL;
/*
* Enable/disable the PPS if requested.
*/
if (hardpps_enable) {
ntv.status |= (STA_PPSTIME | STA_PPSFREQ);
if (!(pll_status & STA_PPSTIME))
sync_status("PPS enabled",
pll_status,
ntv.status);
} else {
ntv.status &= ~(STA_PPSTIME | STA_PPSFREQ);
if (pll_status & STA_PPSTIME)
sync_status("PPS disabled",
pll_status,
ntv.status);
}
if (sys_leap == LEAP_ADDSECOND)
ntv.status |= STA_INS;
else if (sys_leap == LEAP_DELSECOND)
ntv.status |= STA_DEL;
}
/*
* Pass the stuff to the kernel. If it squeals, turn off
* the pps. In any case, fetch the kernel offset,
* frequency and jitter.
*/
ntp_adj_ret = ntp_adjtime(&ntv);
/*
* A squeal is a return status < 0, or a state change.
*/
if ((0 > ntp_adj_ret) || (ntp_adj_ret != kernel_status)) {
kernel_status = ntp_adj_ret;
ntp_adjtime_error_handler(__func__, &ntv, ntp_adj_ret, errno, hardpps_enable, 0, __LINE__ - 1);
}
pll_status = ntv.status;
#ifdef STA_NANO
clock_offset = ntv.offset / 1e9;
#else /* STA_NANO */
clock_offset = ntv.offset / 1e6;
#endif /* STA_NANO */
clock_frequency = FREQTOD(ntv.freq);
/*
* If the kernel PPS is lit, monitor its performance.
*/
if (ntv.status & STA_PPSTIME) {
#ifdef STA_NANO
clock_jitter = ntv.jitter / 1e9;
#else /* STA_NANO */
clock_jitter = ntv.jitter / 1e6;
#endif /* STA_NANO */
}
#if defined(STA_NANO) && NTP_API == 4
/*
* If the TAI changes, update the kernel TAI.
*/
if (loop_tai != sys_tai) {
loop_tai = sys_tai;
ntv.modes = MOD_TAI;
ntv.constant = sys_tai;
if ((ntp_adj_ret = ntp_adjtime(&ntv)) != 0) {
ntp_adjtime_error_handler(__func__, &ntv, ntp_adj_ret, errno, 0, 1, __LINE__ - 1);
}
}
#endif /* STA_NANO */
}
#endif /* KERNEL_PLL */
/*
* Clamp the frequency within the tolerance range and calculate
* the frequency difference since the last update.
*/
if (fabs(clock_frequency) > NTP_MAXFREQ)
msyslog(LOG_NOTICE,
"frequency error %.0f PPM exceeds tolerance %.0f PPM",
clock_frequency * 1e6, NTP_MAXFREQ * 1e6);
dtemp = SQUARE(clock_frequency - drift_comp);
if (clock_frequency > NTP_MAXFREQ)
drift_comp = NTP_MAXFREQ;
else if (clock_frequency < -NTP_MAXFREQ)
drift_comp = -NTP_MAXFREQ;
else
drift_comp = clock_frequency;
/*
* Calculate the wander as the exponentially weighted RMS
* frequency differences. Record the change for the frequency
* file update.
*/
etemp = SQUARE(clock_stability);
clock_stability = SQRT(etemp + (dtemp - etemp) / CLOCK_AVG);
/*
* Here we adjust the time constant by comparing the current
* offset with the clock jitter. If the offset is less than the
* clock jitter times a constant, then the averaging interval is
* increased, otherwise it is decreased. A bit of hysteresis
* helps calm the dance. Works best using burst mode. Don't
* fiddle with the poll during the startup clamp period.
*/
if (freq_cnt > 0) {
tc_counter = 0;
} else if (fabs(clock_offset) < CLOCK_PGATE * clock_jitter) {
tc_counter += sys_poll;
if (tc_counter > CLOCK_LIMIT) {
tc_counter = CLOCK_LIMIT;
if (sys_poll < peer->maxpoll) {
tc_counter = 0;
sys_poll++;
}
}
} else {
tc_counter -= sys_poll << 1;
if (tc_counter < -CLOCK_LIMIT) {
tc_counter = -CLOCK_LIMIT;
if (sys_poll > peer->minpoll) {
tc_counter = 0;
sys_poll--;
}
}
}
/*
* If the time constant has changed, update the poll variables.
*/
if (osys_poll != sys_poll)
poll_update(peer, sys_poll);
/*
* Yibbidy, yibbbidy, yibbidy; that'h all folks.
*/
record_loop_stats(clock_offset, drift_comp, clock_jitter,
clock_stability, sys_poll);
#ifdef DEBUG
if (debug)
printf(
"local_clock: offset %.9f jit %.9f freq %.3f stab %.3f poll %d\n",
clock_offset, clock_jitter, drift_comp * 1e6,
clock_stability * 1e6, sys_poll);
#endif /* DEBUG */
return (rval);
#endif /* LOCKCLOCK */
}
/*
* adj_host_clock - Called once every second to update the local clock.
*
* LOCKCLOCK: The only thing this routine does is increment the
* sys_rootdisp variable.
*/
void
adj_host_clock(
void
)
{
double offset_adj;
double freq_adj;
/*
* Update the dispersion since the last update. In contrast to
* NTPv3, NTPv4 does not declare unsynchronized after one day,
* since the dispersion check serves this function. Also,
* since the poll interval can exceed one day, the old test
* would be counterproductive. During the startup clamp period, the
* time constant is clamped at 2.
*/
sys_rootdisp += clock_phi;
#ifndef LOCKCLOCK
if (!ntp_enable || mode_ntpdate)
return;
/*
* Determine the phase adjustment. The gain factor (denominator)
* increases with poll interval, so is dominated by the FLL
* above the Allan intercept. Note the reduced time constant at
* startup.
*/
if (state != EVNT_SYNC) {
offset_adj = 0.;
} else if (freq_cnt > 0) {
offset_adj = clock_offset / (CLOCK_PLL * ULOGTOD(1));
freq_cnt--;
#ifdef KERNEL_PLL
} else if (pll_control && kern_enable) {
offset_adj = 0.;
#endif /* KERNEL_PLL */
} else {
offset_adj = clock_offset / (CLOCK_PLL * ULOGTOD(sys_poll));
}
/*
* If the kernel discipline is enabled the frequency correction
* drift_comp has already been engaged via ntp_adjtime() in
* set_freq(). Otherwise it is a component of the adj_systime()
* offset.
*/
#ifdef KERNEL_PLL
if (pll_control && kern_enable)
freq_adj = 0.;
else
#endif /* KERNEL_PLL */
freq_adj = drift_comp;
/* Bound absolute value of total adjustment to NTP_MAXFREQ. */
if (offset_adj + freq_adj > NTP_MAXFREQ)
offset_adj = NTP_MAXFREQ - freq_adj;
else if (offset_adj + freq_adj < -NTP_MAXFREQ)
offset_adj = -NTP_MAXFREQ - freq_adj;
clock_offset -= offset_adj;
/*
* Windows port adj_systime() must be called each second,
* even if the argument is zero, to ease emulation of
* adjtime() using Windows' slew API which controls the rate
* but does not automatically stop slewing when an offset
* has decayed to zero.
*/
adj_systime(offset_adj + freq_adj);
#endif /* LOCKCLOCK */
}
static void
check_leapsec(
u_int32 now ,
const time_t * tpiv ,
int/*BOOL*/ reset)
{
static const char leapmsg_p_step[] =
"Positive leap second, stepped backward.";
static const char leapmsg_p_slew[] =
"Positive leap second, no step correction. "
"System clock will be inaccurate for a long time.";
static const char leapmsg_n_step[] =
"Negative leap second, stepped forward.";
static const char leapmsg_n_slew[] =
"Negative leap second, no step correction. "
"System clock will be inaccurate for a long time.";
leap_result_t lsdata;
u_int32 lsprox;
#ifdef AUTOKEY
int/*BOOL*/ update_autokey = FALSE;
#endif
#ifndef SYS_WINNT /* WinNT port has its own leap second handling */
# ifdef KERNEL_PLL
leapsec_electric(pll_control && kern_enable);
# else
leapsec_electric(0);
# endif
#endif
#ifdef LEAP_SMEAR
leap_smear.enabled = leap_smear_intv != 0;
#endif
if (reset) {
lsprox = LSPROX_NOWARN;
leapsec_reset_frame();
memset(&lsdata, 0, sizeof(lsdata));
} else {
int fired = leapsec_query(&lsdata, now, tpiv);
DPRINTF(1, ("*** leapsec_query: fired %i, now %u (0x%08X), tai_diff %i, ddist %u\n",
fired, now, now, lsdata.tai_diff, lsdata.ddist));
#ifdef LEAP_SMEAR
leap_smear.in_progress = 0;
leap_smear.doffset = 0.0;
if (leap_smear.enabled) {
if (lsdata.tai_diff) {
if (leap_smear.interval == 0) {
leap_smear.interval = leap_smear_intv;
leap_smear.intv_end = lsdata.ttime.Q_s;
leap_smear.intv_start = leap_smear.intv_end - leap_smear.interval;
DPRINTF(1, ("*** leapsec_query: setting leap_smear interval %li, begin %.0f, end %.0f\n",
leap_smear.interval, leap_smear.intv_start, leap_smear.intv_end));
}
}
else {
if (leap_smear.interval)
DPRINTF(1, ("*** leapsec_query: clearing leap_smear interval\n"));
leap_smear.interval = 0;
}
if (leap_smear.interval) {
double dtemp = now;
if (dtemp >= leap_smear.intv_start && dtemp <= leap_smear.intv_end) {
double leap_smear_time = dtemp - leap_smear.intv_start;
/*
* For now we just do a linear interpolation over the smear interval
*/
#if 0
// linear interpolation
leap_smear.doffset = -(leap_smear_time * lsdata.tai_diff / leap_smear.interval);
#else
// Google approach: lie(t) = (1.0 - cos(pi * t / w)) / 2.0
leap_smear.doffset = -((double) lsdata.tai_diff - cos( M_PI * leap_smear_time / leap_smear.interval)) / 2.0;
#endif
/*
* TODO see if we're inside an inserted leap second, so we need to compute
* leap_smear.doffset = 1.0 - leap_smear.doffset
*/
leap_smear.in_progress = 1;
#if 0 && defined( DEBUG )
msyslog(LOG_NOTICE, "*** leapsec_query: [%.0f:%.0f] (%li), now %u (%.0f), smear offset %.6f ms\n",
leap_smear.intv_start, leap_smear.intv_end, leap_smear.interval,
now, leap_smear_time, leap_smear.doffset);
#else
DPRINTF(1, ("*** leapsec_query: [%.0f:%.0f] (%li), now %u (%.0f), smear offset %.6f ms\n",
leap_smear.intv_start, leap_smear.intv_end, leap_smear.interval,
now, leap_smear_time, leap_smear.doffset));
#endif
}
}
}
else
leap_smear.interval = 0;
/*
* Update the current leap smear offset, eventually 0.0 if outside smear interval.
*/
DTOLFP(leap_smear.doffset, &leap_smear.offset);
#endif /* LEAP_SMEAR */
if (fired) {
/* Full hit. Eventually step the clock, but always
* announce the leap event has happened.
*/
const char *leapmsg = NULL;
if (lsdata.warped < 0) {
if (clock_max_back > 0.0 &&
clock_max_back < abs(lsdata.warped)) {
step_systime(lsdata.warped);
leapmsg = leapmsg_p_step;
} else {
leapmsg = leapmsg_p_slew;
}
} else if (lsdata.warped > 0) {
if (clock_max_fwd > 0.0 &&
clock_max_fwd < abs(lsdata.warped)) {
step_systime(lsdata.warped);
leapmsg = leapmsg_n_step;
} else {
leapmsg = leapmsg_n_slew;
}
}
if (leapmsg)
msyslog(LOG_NOTICE, "%s", leapmsg);
report_event(EVNT_LEAP, NULL, NULL);
#ifdef AUTOKEY
update_autokey = TRUE;
#endif
lsprox = LSPROX_NOWARN;
leapsec = LSPROX_NOWARN;
sys_tai = lsdata.tai_offs;
} else {
#ifdef AUTOKEY
update_autokey = (sys_tai != (u_int)lsdata.tai_offs);
#endif
lsprox = lsdata.proximity;
sys_tai = lsdata.tai_offs;
}
}
/* We guard against panic alarming during the red alert phase.
* Strange and evil things might happen if we go from stone cold
* to piping hot in one step. If things are already that wobbly,
* we let the normal clock correction take over, even if a jump
* is involved.
* Also make sure the alarming events are edge-triggered, that is,
* ceated only when the threshold is crossed.
*/
if ( (leapsec > 0 || lsprox < LSPROX_ALERT)
&& leapsec < lsprox ) {
if ( leapsec < LSPROX_SCHEDULE
&& lsprox >= LSPROX_SCHEDULE) {
if (lsdata.dynamic)
report_event(PEVNT_ARMED, sys_peer, NULL);
else
report_event(EVNT_ARMED, NULL, NULL);
}
leapsec = lsprox;
}
if (leapsec > lsprox) {
if ( leapsec >= LSPROX_SCHEDULE
&& lsprox < LSPROX_SCHEDULE) {
report_event(EVNT_DISARMED, NULL, NULL);
}
leapsec = lsprox;
}
if (leapsec >= LSPROX_SCHEDULE)
leapdif = lsdata.tai_diff;
else
leapdif = 0;
check_leap_sec_in_progress(&lsdata);
#ifdef AUTOKEY
if (update_autokey)
crypto_update_taichange();
#endif
}
static void
check_leapsec(
u_int32 now ,
const time_t * tpiv ,
int/*BOOL*/ reset)
{
leap_result_t lsdata;
u_int32 lsprox;
#ifndef SYS_WINNT /* WinNT port has its own leap second handling */
# ifdef KERNEL_PLL
leapsec_electric(pll_control && kern_enable);
# else
leapsec_electric(0);
# endif
#endif
if (reset) {
lsprox = LSPROX_NOWARN;
leapsec_reset_frame();
memset(&lsdata, 0, sizeof(lsdata));
} else if (leapsec_query(&lsdata, now, tpiv)) {
/* Full hit. Eventually step the clock, but always
* announce the leap event has happened.
*/
if (lsdata.warped < 0) {
step_systime(lsdata.warped);
msyslog(LOG_NOTICE, "Inserting positive leap second.");
} else if (lsdata.warped > 0) {
step_systime(lsdata.warped);
msyslog(LOG_NOTICE, "Inserting negative leap second.");
}
report_event(EVNT_LEAP, NULL, NULL);
lsprox = LSPROX_NOWARN;
leapsec = LSPROX_NOWARN;
sys_tai = lsdata.tai_offs;
} else {
lsprox = lsdata.proximity;
sys_tai = lsdata.tai_offs;
}
/* We guard against panic alarming during the red alert phase.
* Strange and evil things might happen if we go from stone cold
* to piping hot in one step. If things are already that wobbly,
* we let the normal clock correction take over, even if a jump
* is involved.
* Also make sure the alarming events are edge-triggered, that is,
* ceated only when the threshold is crossed.
*/
if ( (leapsec > 0 || lsprox < LSPROX_ALERT)
&& leapsec < lsprox ) {
if ( leapsec < LSPROX_SCHEDULE
&& lsprox >= LSPROX_SCHEDULE) {
if (lsdata.dynamic)
report_event(PEVNT_ARMED, sys_peer, NULL);
else
report_event(EVNT_ARMED, NULL, NULL);
}
leapsec = lsprox;
}
if (leapsec > lsprox) {
if ( leapsec >= LSPROX_SCHEDULE
&& lsprox < LSPROX_SCHEDULE) {
report_event(EVNT_DISARMED, NULL, NULL);
}
leapsec = lsprox;
}
if (leapsec >= LSPROX_SCHEDULE)
leapdif = lsdata.tai_diff;
else
leapdif = 0;
}
/*
* local_clock - the NTP logical clock loop filter.
*
* Return codes:
* -1 update ignored: exceeds panic threshold
* 0 update ignored: popcorn or exceeds step threshold
* 1 clock was slewed
* 2 clock was stepped
*
* LOCKCLOCK: The only thing this routine does is set the
* sys_rootdispersion variable equal to the peer dispersion.
*/
int
local_clock(
struct peer *peer, /* synch source peer structure */
double fp_offset /* clock offset (s) */
)
{
int rval; /* return code */
u_long mu; /* interval since last update (s) */
double flladj; /* FLL frequency adjustment (ppm) */
double plladj; /* PLL frequency adjustment (ppm) */
double clock_frequency; /* clock frequency adjustment (ppm) */
double dtemp, etemp; /* double temps */
#ifdef OPENSSL
u_int32 *tpt;
int i;
u_int len;
long togo;
#endif /* OPENSSL */
/*
* If the loop is opened or the NIST LOCKCLOCK is in use,
* monitor and record the offsets anyway in order to determine
* the open-loop response and then go home.
*/
#ifdef DEBUG
if (debug)
printf(
"local_clock: assocID %d offset %.9f freq %.3f state %d\n",
peer->associd, fp_offset, drift_comp * 1e6, state);
#endif
#ifdef LOCKCLOCK
return (0);
#else /* LOCKCLOCK */
if (!ntp_enable) {
record_loop_stats(fp_offset, drift_comp, clock_jitter,
clock_stability, sys_poll);
return (0);
}
/*
* If the clock is way off, panic is declared. The clock_panic
* defaults to 1000 s; if set to zero, the panic will never
* occur. The allow_panic defaults to FALSE, so the first panic
* will exit. It can be set TRUE by a command line option, in
* which case the clock will be set anyway and time marches on.
* But, allow_panic will be set FALSE when the update is less
* than the step threshold; so, subsequent panics will exit.
*/
if (fabs(fp_offset) > clock_panic && clock_panic > 0 &&
!allow_panic) {
msyslog(LOG_ERR,
"time correction of %.0f seconds exceeds sanity limit (%.0f); set clock manually to the correct UTC time.",
fp_offset, clock_panic);
return (-1);
}
/*
* If simulating ntpdate, set the clock directly, rather than
* using the discipline. The clock_max defines the step
* threshold, above which the clock will be stepped instead of
* slewed. The value defaults to 128 ms, but can be set to even
* unreasonable values. If set to zero, the clock will never be
* stepped. Note that a slew will persist beyond the life of
* this program.
*
* Note that if ntpdate is active, the terminal does not detach,
* so the termination comments print directly to the console.
*/
if (mode_ntpdate) {
if (fabs(fp_offset) > clock_max && clock_max > 0) {
step_systime(fp_offset);
msyslog(LOG_NOTICE, "time reset %+.6f s",
fp_offset);
printf("ntpd: time set %+.6fs\n", fp_offset);
} else {
adj_systime(fp_offset);
msyslog(LOG_NOTICE, "time slew %+.6f s",
fp_offset);
printf("ntpd: time slew %+.6fs\n", fp_offset);
}
record_loop_stats(fp_offset, drift_comp, clock_jitter,
clock_stability, sys_poll);
exit (0);
}
/*
* The huff-n'-puff filter finds the lowest delay in the recent
* interval. This is used to correct the offset by one-half the
* difference between the sample delay and minimum delay. This
* is most effective if the delays are highly assymetric and
* clockhopping is avoided and the clock frequency wander is
* relatively small.
*
* Note either there is no prefer peer or this update is from
* the prefer peer.
*/
if (sys_huffpuff != NULL && (sys_prefer == NULL || sys_prefer ==
peer)) {
if (peer->delay < sys_huffpuff[sys_huffptr])
sys_huffpuff[sys_huffptr] = peer->delay;
if (peer->delay < sys_mindly)
sys_mindly = peer->delay;
if (fp_offset > 0)
dtemp = -(peer->delay - sys_mindly) / 2;
else
dtemp = (peer->delay - sys_mindly) / 2;
fp_offset += dtemp;
#ifdef DEBUG
if (debug)
printf(
"local_clock: size %d mindly %.6f huffpuff %.6f\n",
sys_hufflen, sys_mindly, dtemp);
#endif
}
/*
* Clock state machine transition function. This is where the
* action is and defines how the system reacts to large phase
* and frequency errors. There are two main regimes: when the
* offset exceeds the step threshold and when it does not.
* However, if the step threshold is set to zero, a step will
* never occur. See the instruction manual for the details how
* these actions interact with the command line options.
*
* Note the system poll is set to minpoll only if the clock is
* stepped. Note also the kernel is disabled if step is
* disabled or greater than 0.5 s.
*/
clock_frequency = flladj = plladj = 0;
mu = peer->epoch - sys_clocktime;
if (clock_max == 0 || clock_max > 0.5)
kern_enable = 0;
rval = 1;
if (fabs(fp_offset) > clock_max && clock_max > 0) {
switch (state) {
/*
* In S_SYNC state we ignore the first outlyer amd
* switch to S_SPIK state.
*/
case S_SYNC:
state = S_SPIK;
return (0);
/*
* In S_FREQ state we ignore outlyers and inlyers. At
* the first outlyer after the stepout threshold,
* compute the apparent frequency correction and step
* the phase.
*/
case S_FREQ:
if (mu < clock_minstep)
return (0);
clock_frequency = (fp_offset - clock_offset) /
mu;
/* fall through to S_SPIK */
/*
* In S_SPIK state we ignore succeeding outlyers until
* either an inlyer is found or the stepout threshold is
* exceeded.
*/
case S_SPIK:
if (mu < clock_minstep)
return (0);
/* fall through to default */
/*
* We get here by default in S_NSET and S_FSET states
* and from above in S_FREQ or S_SPIK states.
*
* In S_NSET state an initial frequency correction is
* not available, usually because the frequency file has
* not yet been written. Since the time is outside the
* step threshold, the clock is stepped. The frequency
* will be set directly following the stepout interval.
*
* In S_FSET state the initial frequency has been set
* from the frequency file. Since the time is outside
* the step threshold, the clock is stepped immediately,
* rather than after the stepout interval. Guys get
* nervous if it takes 17 minutes to set the clock for
* the first time.
*
* In S_FREQ and S_SPIK states the stepout threshold has
* expired and the phase is still above the step
* threshold. Note that a single spike greater than the
* step threshold is always suppressed, even at the
* longer poll intervals.
*/
default:
step_systime(fp_offset);
msyslog(LOG_NOTICE, "time reset %+.6f s",
fp_offset);
reinit_timer();
tc_counter = 0;
sys_poll = NTP_MINPOLL;
sys_tai = 0;
clock_jitter = LOGTOD(sys_precision);
rval = 2;
if (state == S_NSET) {
rstclock(S_FREQ, peer->epoch, 0);
return (rval);
}
break;
}
rstclock(S_SYNC, peer->epoch, 0);
} else {
/*
* The offset is less than the step threshold. Calculate
* the jitter as the exponentially weighted offset
* differences.
*/
etemp = SQUARE(clock_jitter);
dtemp = SQUARE(max(fabs(fp_offset - last_offset),
LOGTOD(sys_precision)));
clock_jitter = SQRT(etemp + (dtemp - etemp) /
CLOCK_AVG);
switch (state) {
/*
* In S_NSET state this is the first update received and
* the frequency has not been initialized. Adjust the
* phase, but do not adjust the frequency until after
* the stepout threshold.
*/
case S_NSET:
rstclock(S_FREQ, peer->epoch, fp_offset);
break;
/*
* In S_FSET state this is the first update received and
* the frequency has been initialized. Adjust the phase,
* but do not adjust the frequency until the next
* update.
*/
case S_FSET:
rstclock(S_SYNC, peer->epoch, fp_offset);
break;
/*
* In S_FREQ state ignore updates until the stepout
* threshold. After that, correct the phase and
* frequency and switch to S_SYNC state.
*/
case S_FREQ:
if (mu < clock_minstep)
return (0);
clock_frequency = (fp_offset - clock_offset) /
mu;
rstclock(S_SYNC, peer->epoch, fp_offset);
break;
/*
* We get here by default in S_SYNC and S_SPIK states.
* Here we compute the frequency update due to PLL and
* FLL contributions.
*/
default:
allow_panic = FALSE;
/*
* The FLL and PLL frequency gain constants
* depend on the poll interval and Allan
* intercept. The PLL is always used, but
* becomes ineffective above the Allan
* intercept. The FLL is not used below one-half
* the Allan intercept. Above that the loop gain
* increases in steps to 1 / CLOCK_AVG.
*/
if (ULOGTOD(sys_poll) > allan_xpt / 2) {
dtemp = CLOCK_FLL - sys_poll;
flladj = (fp_offset - clock_offset) /
(max(mu, allan_xpt) * dtemp);
}
/*
* For the PLL the integration interval
* (numerator) is the minimum of the update
* interval and poll interval. This allows
* oversampling, but not undersampling.
*/
etemp = min(mu, (u_long)ULOGTOD(sys_poll));
dtemp = 4 * CLOCK_PLL * ULOGTOD(sys_poll);
plladj = fp_offset * etemp / (dtemp * dtemp);
rstclock(S_SYNC, peer->epoch, fp_offset);
break;
}
}
#ifdef OPENSSL
/*
* Scan the loopsecond table to determine the TAI offset. If
* there is a scheduled leap in future, set the leap warning,
* but only if less than 30 days before the leap.
*/
tpt = (u_int32 *)tai_leap.ptr;
len = ntohl(tai_leap.vallen) / sizeof(u_int32);
if (tpt != NULL) {
for (i = 0; i < len; i++) {
togo = (long)ntohl(tpt[i]) -
(long)peer->rec.l_ui;
if (togo > 0) {
if (togo < CLOCK_JUNE)
leap_next |= LEAP_ADDSECOND;
break;
}
}
#if defined(STA_NANO) && NTP_API == 4
if (pll_control && kern_enable && sys_tai == 0) {
memset(&ntv, 0, sizeof(ntv));
ntv.modes = MOD_TAI;
ntv.constant = i + TAI_1972 - 1;
ntp_adjtime(&ntv);
}
#endif /* STA_NANO */
sys_tai = i + TAI_1972 - 1;
}
#endif /* OPENSSL */
#ifdef KERNEL_PLL
/*
* This code segment works when clock adjustments are made using
* precision time kernel support and the ntp_adjtime() system
* call. This support is available in Solaris 2.6 and later,
* Digital Unix 4.0 and later, FreeBSD, Linux and specially
* modified kernels for HP-UX 9 and Ultrix 4. In the case of the
* DECstation 5000/240 and Alpha AXP, additional kernel
* modifications provide a true microsecond clock and nanosecond
* clock, respectively.
*
* Important note: The kernel discipline is used only if the
* step threshold is less than 0.5 s, as anything higher can
* lead to overflow problems. This might occur if some misguided
* lad set the step threshold to something ridiculous.
*/
if (pll_control && kern_enable) {
/*
* We initialize the structure for the ntp_adjtime()
* system call. We have to convert everything to
* microseconds or nanoseconds first. Do not update the
* system variables if the ext_enable flag is set. In
* this case, the external clock driver will update the
* variables, which will be read later by the local
* clock driver. Afterwards, remember the time and
* frequency offsets for jitter and stability values and
* to update the frequency file.
*/
memset(&ntv, 0, sizeof(ntv));
if (ext_enable) {
ntv.modes = MOD_STATUS;
} else {
struct tm *tm = NULL;
time_t tstamp;
#ifdef STA_NANO
ntv.modes = MOD_BITS | MOD_NANO;
#else /* STA_NANO */
ntv.modes = MOD_BITS;
#endif /* STA_NANO */
if (clock_offset < 0)
dtemp = -.5;
else
dtemp = .5;
#ifdef STA_NANO
ntv.offset = (int32)(clock_offset * 1e9 +
dtemp);
ntv.constant = sys_poll;
#else /* STA_NANO */
ntv.offset = (int32)(clock_offset * 1e6 +
dtemp);
ntv.constant = sys_poll - 4;
#endif /* STA_NANO */
/*
* The frequency is set directly only if
* clock_frequency is nonzero coming out of FREQ
* state.
*/
if (clock_frequency != 0) {
ntv.modes |= MOD_FREQUENCY;
ntv.freq = (int32)((clock_frequency +
drift_comp) * 65536e6);
}
ntv.esterror = (u_int32)(clock_jitter * 1e6);
ntv.maxerror = (u_int32)((sys_rootdelay / 2 +
sys_rootdispersion) * 1e6);
ntv.status = STA_PLL;
/*
* Set the leap bits in the status word, but
* only on the last day of June or December.
*/
tstamp = peer->rec.l_ui - JAN_1970;
tm = gmtime(&tstamp);
if (tm != NULL) {
if ((tm->tm_mon + 1 == 6 &&
tm->tm_mday == 30) || (tm->tm_mon +
1 == 12 && tm->tm_mday == 31)) {
if (leap_next & LEAP_ADDSECOND)
ntv.status |= STA_INS;
else if (leap_next &
LEAP_DELSECOND)
ntv.status |= STA_DEL;
}
}
/*
* If the PPS signal is up and enabled, light
* the frequency bit. If the PPS driver is
* working, light the phase bit as well. If not,
* douse the lights, since somebody else may
* have left the switch on.
*/
if (pps_enable && pll_status & STA_PPSSIGNAL) {
ntv.status |= STA_PPSFREQ;
if (pps_stratum < STRATUM_UNSPEC)
ntv.status |= STA_PPSTIME;
} else {
ntv.status &= ~(STA_PPSFREQ |
STA_PPSTIME);
}
}
/*
* Pass the stuff to the kernel. If it squeals, turn off
* the pig. In any case, fetch the kernel offset and
* frequency and pretend we did it here.
*/
if (ntp_adjtime(&ntv) == TIME_ERROR) {
NLOG(NLOG_SYNCEVENT | NLOG_SYSEVENT)
msyslog(LOG_NOTICE,
"kernel time sync error %04x", ntv.status);
ntv.status &= ~(STA_PPSFREQ | STA_PPSTIME);
}
pll_status = ntv.status;
#ifdef STA_NANO
clock_offset = ntv.offset / 1e9;
#else /* STA_NANO */
clock_offset = ntv.offset / 1e6;
#endif /* STA_NANO */
clock_frequency = ntv.freq / 65536e6;
flladj = plladj = 0;
/*
* If the kernel PPS is lit, monitor its performance.
*/
if (ntv.status & STA_PPSTIME) {
pps_control = current_time;
#ifdef STA_NANO
clock_jitter = ntv.jitter / 1e9;
#else /* STA_NANO */
clock_jitter = ntv.jitter / 1e6;
#endif /* STA_NANO */
}
} else {
#endif /* KERNEL_PLL */
/*
* We get here if the kernel discipline is not enabled.
* Adjust the clock frequency as the sum of the directly
* computed frequency (if measured) and the PLL and FLL
* increments.
*/
clock_frequency = drift_comp + clock_frequency +
flladj + plladj;
#ifdef KERNEL_PLL
}
#endif /* KERNEL_PLL */
/*
* Clamp the frequency within the tolerance range and calculate
* the frequency change since the last update.
*/
if (fabs(clock_frequency) > NTP_MAXFREQ)
NLOG(NLOG_SYNCEVENT | NLOG_SYSEVENT)
msyslog(LOG_NOTICE,
"frequency error %.0f PPM exceeds tolerance %.0f PPM",
clock_frequency * 1e6, NTP_MAXFREQ * 1e6);
dtemp = SQUARE(clock_frequency - drift_comp);
if (clock_frequency > NTP_MAXFREQ)
drift_comp = NTP_MAXFREQ;
else if (clock_frequency < -NTP_MAXFREQ)
drift_comp = -NTP_MAXFREQ;
else
drift_comp = clock_frequency;
/*
* Calculate the wander as the exponentially weighted frequency
* differences.
*/
etemp = SQUARE(clock_stability);
clock_stability = SQRT(etemp + (dtemp - etemp) / CLOCK_AVG);
/*
* Here we adjust the poll interval by comparing the current
* offset with the clock jitter. If the offset is less than the
* clock jitter times a constant, then the averaging interval is
* increased, otherwise it is decreased. A bit of hysteresis
* helps calm the dance. Works best using burst mode.
*/
if (fabs(clock_offset) < CLOCK_PGATE * clock_jitter) {
tc_counter += sys_poll;
if (tc_counter > CLOCK_LIMIT) {
tc_counter = CLOCK_LIMIT;
if (sys_poll < peer->maxpoll) {
tc_counter = 0;
sys_poll++;
}
}
} else {
tc_counter -= sys_poll << 1;
if (tc_counter < -CLOCK_LIMIT) {
tc_counter = -CLOCK_LIMIT;
if (sys_poll > peer->minpoll) {
tc_counter = 0;
sys_poll--;
}
}
}
/*
* Yibbidy, yibbbidy, yibbidy; that'h all folks.
*/
record_loop_stats(clock_offset, drift_comp, clock_jitter,
clock_stability, sys_poll);
#ifdef DEBUG
if (debug)
printf(
"local_clock: mu %lu jitr %.6f freq %.3f stab %.6f poll %d count %d\n",
mu, clock_jitter, drift_comp * 1e6,
clock_stability * 1e6, sys_poll, tc_counter);
#endif /* DEBUG */
return (rval);
#endif /* LOCKCLOCK */
}