+++ /dev/null
-/*
- * ntp_loopfilter.c - implements the NTP loop filter algorithm
- *
- */
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
-
-#include <stdio.h>
-#include <ctype.h>
-#include <sys/time.h>
-
-
-#include <signal.h>
-#include <errno.h>
-#include <setjmp.h>
-#include "ntpd.h"
-#include "ntp_io.h"
-#include "ntp_unixtime.h"
-#include "ntp_stdlib.h"
-
-#if defined(VMS) && defined(VMS_LOCALUNIT) /*wjm*/
-#include "ntp_refclock.h"
-#endif /* VMS */
-
-#ifdef KERNEL_PLL
-#ifdef HAVE_SYS_TIMEX_H
-#include <sys/timex.h>
-#endif
-#ifdef NTP_SYSCALLS_STD
-#define ntp_adjtime(t) syscall(SYS_ntp_adjtime, (t))
-#else /* NOT NTP_SYSCALLS_STD */
-#ifdef HAVE___ADJTIMEX
-#define ntp_adjtime(t) __adjtimex((t))
-#endif
-#endif /* NOT NTP_SYSCALLS_STD */
-#endif /* KERNEL_PLL */
-
-/*
- * This is an implementation of the clock discipline algorithm described
- * in UDel TR 97-4-3, as amended. It operates as an adaptive parameter,
- * hybrid phase/frequency-lock loop. A number of sanity checks are
- * included to protect against timewarps, timespikes and general mayhem.
- * All units are in s and s/s, unless noted otherwise.
- */
-#define CLOCK_MAX .128 /* default max offset (s) */
-#define CLOCK_PANIC 1000. /* default panic offset (s) */
-#define CLOCK_MAXSTAB 2e-6 /* max frequency stability */
-#define CLOCK_MAXERR 1e-2 /* max phase jitter (s) */
-#define SHIFT_PLL 4 /* PLL loop gain (shift) */
-#define CLOCK_AVG 4. /* FLL loop gain */
-#define CLOCK_MINSEC 256. /* min FLL update interval (s) */
-#define CLOCK_MINSTEP 900. /* step-change timeout (s) */
-#define CLOCK_DAY 86400. /* one day of seconds */
-#define CLOCK_LIMIT 30 /* poll-adjust threshold */
-#define CLOCK_PGATE 4. /* poll-adjust gate */
-#define CLOCK_ALLAN 1024. /* min Allan intercept (s) */
-#define CLOCK_ADF 1e11 /* Allan deviation factor */
-
-/*
- * Clock discipline state machine. This is used to control the
- * synchronization behavior during initialization and following a
- * timewarp.
- */
-#define S_NSET 0 /* clock never set */
-#define S_FSET 1 /* frequency set from the drift file */
-#define S_TSET 2 /* time set */
-#define S_FREQ 3 /* frequency mode */
-#define S_SYNC 4 /* clock synchronized */
-#define S_SPIK 5 /* spike detected */
-
-/*
- * Kernel PLL/PPS state machine. This is used with the kernel PLL
- * modifications described in the README.kernel file.
- *
- * If kernel support for the ntp_adjtime() system call is available, the
- * ntp_control flag is set. The ntp_enable and kern_enable flags can be
- * set at configuration time or run time using ntpdc. If ntp_enable is
- * false, the discipline loop is unlocked and no correctios of any kind
- * are made. If both ntp_control and kern_enable are set, the kernel
- * support is used as described above; if false, the kernel is bypassed
- * entirely and the daemon PLL used instead.
- *
- * Each update to a prefer peer sets pps_update if it survives the
- * intersection algorithm and its time is within range. The PPS time
- * discipline is enabled (STA_PPSTIME bit set in the status word) when
- * pps_update is true and the PPS frequency discipline is enabled. If
- * the PPS time discipline is enabled and the kernel reports a PPS
- * signal is present, the pps_control variable is set to the current
- * time. If the current time is later than pps_control by PPS_MAXAGE
- * (120 s), this variable is set to zero.
- *
- * If an external clock is present, the clock driver sets STA_CLK in the
- * status word. When the local clock driver sees this bit, it updates
- * via this routine, which then calls ntp_adjtime() with the STA_PLL bit
- * set to zero, in which case the system clock is not adjusted. This is
- * also a signal for the external clock driver to discipline the system
- * clock.
- */
-#define PPS_MAXAGE 120 /* kernel pps signal timeout (s) */
-
-/*
- * Program variables
- */
-double clock_offset; /* clock offset adjustment (ppm) */
-double drift_comp; /* clock frequency (ppm) */
-double clock_stability; /* clock stability (ppm) */
-double clock_max = CLOCK_MAX; /* max offset allowed before step (s) */
-double clock_panic = CLOCK_PANIC; /* max offset allowed before panic */
-u_long pps_control; /* last pps sample time */
-static void rstclock P((int)); /* state transition function */
-
-#ifdef KERNEL_PLL
-static int pll_status; /* status bits for kernel pll */
-#endif /* KERNEL_PLL */
-
-/*
- * Clock state machine control flags
- */
-int ntp_enable; /* clock discipline enabled */
-int pll_control; /* kernel support available */
-int kern_enable; /* kernel support enabled */
-#ifdef STA_NANO
-int pll_nano; /* nanosecond kernel */
-#endif /* STA_NANO */
-int ext_enable; /* external clock enabled */
-int pps_update; /* pps update valid */
-int allow_set_backward = TRUE; /* step corrections allowed */
-int correct_any = FALSE; /* corrections > 1000 s allowed */
-
-#ifdef STA_NANO
-int pll_nano; /* nanosecond kernel switch */
-#endif /* STA_NANO */
-
-/*
- * Clock state machine variables
- */
-u_char sys_poll; /* log2 of system poll interval */
-int state; /* clock discipline state */
-int tc_counter; /* poll-adjust counter */
-u_long last_time; /* time of last clock update (s) */
-double last_offset; /* last clock offset (s) */
-double allan_xpt; /* Allan intercept (s) */
-double sys_error; /* system standard error (s) */
-
-/*
- * Imported from ntp_proto.c module
- */
-extern double sys_rootdelay; /* root delay */
-extern double sys_rootdispersion; /* root dispersion */
-extern s_char sys_precision; /* local clock precision */
-extern struct peer *sys_peer; /* system peer pointer */
-extern u_char sys_leap; /* system leap bits */
-extern l_fp sys_reftime; /* time at last update */
-
-/*
- * Imported from the library
- */
-extern double sys_maxfreq; /* max frequency correction */
-
-/*
- * Imported from ntp_io.c module
- */
-extern struct interface *loopback_interface;
-
-/*
- * Imported from ntpd.c module
- */
-extern int debug; /* global debug flag */
-
-/*
- * Imported from ntp_io.c module
- */
-extern u_long current_time; /* like it says, in seconds */
-
-#if defined(KERNEL_PLL)
-/* Emacs cc-mode goes nuts if we split the next line... */
-#define MOD_BITS (MOD_OFFSET | MOD_MAXERROR | MOD_ESTERROR | \
- MOD_STATUS | MOD_TIMECONST)
-#ifdef NTP_SYSCALLS_STD
-#ifdef DECL_SYSCALL
-extern int syscall P((int, void *, ...));
-#endif /* DECL_SYSCALL */
-#endif /* NTP_SYSCALLS_STD */
-void pll_trap P((int));
-#ifdef SIGSYS
-static struct sigaction sigsys; /* current sigaction status */
-static struct sigaction newsigsys; /* new sigaction status */
-static sigjmp_buf env; /* environment var. for pll_trap() */
-#endif /* SIGSYS */
-#endif /* KERNEL_PLL */
-
-/*
- * init_loopfilter - initialize loop filter data
- */
-void
-init_loopfilter(void)
-{
- /*
- * Initialize state variables. Initially, we expect no drift
- * file, so set the state to S_NSET.
- */
- rstclock(S_NSET);
-}
-
-/*
- * local_clock - the NTP logical clock loop filter. Returns 1 if the
- * clock was stepped, 0 if it was slewed and -1 if it is hopeless.
- */
-int
-local_clock(
- struct peer *peer, /* synch source peer structure */
- double fp_offset, /* clock offset */
- double epsil /* jittter (square) */
- )
-{
- double mu; /* interval since last update (s) */
- double oerror; /* previous error estimate */
- double flladj; /* FLL frequency adjustment (ppm) */
- double plladj; /* PLL frequency adjustment (ppm) */
- double clock_frequency; /* clock frequency (ppm) adjustment */
- double dtemp, etemp; /* double temps */
- int retval; /* return value */
-
-#if defined(KERNEL_PLL)
- struct timex ntv; /* kernel interface structure */
-#endif /* KERNEL_PLL */
-
-#ifdef DEBUG
- if (debug)
- printf(
- "local_clock: offset %.6f jitter %.6f state %d\n",
- fp_offset, SQRT(epsil), state);
-#endif
- if (!ntp_enable)
- return(0);
-
- /*
- * If the clock is way off, don't tempt fate by correcting it.
- */
- if (fabs(fp_offset) >= clock_panic && !correct_any) {
- msyslog(LOG_ERR,
- "time error %.0f over %d seconds; set clock manually)",
- fp_offset, clock_panic);
- return (-1);
- }
-
- /*
- * If the clock has never been set, set it and initialize the
- * discipline parameters. We then switch to frequency mode to
- * speed the inital convergence process. If lucky, after an hour
- * the ntp.drift file is created and initialized and we don't
- * get here again.
- */
- if (state == S_NSET) {
- step_systime(fp_offset);
- NLOG(NLOG_SYNCEVENT|NLOG_SYSEVENT)
- msyslog(LOG_NOTICE, "time set %.6f s", fp_offset);
- rstclock(S_TSET);
- rstclock(S_FREQ);
- return (1);
- }
-
- /*
- * Update the jitter estimate.
- */
- oerror = sys_error;
- dtemp = SQUARE(sys_error);
- sys_error = SQRT(dtemp + (epsil - dtemp) / CLOCK_AVG);
-
- /*
- * 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
- * phase error exceeds the maximum allowed for ordinary tracking
- * and otherwise when it does not.
- */
- retval = 0;
- clock_frequency = flladj = plladj = 0;
- mu = current_time - last_time;
- if (fabs(fp_offset) > clock_max) {
- switch (state) {
-
- /*
- * In S_TSET state the time has been set at the last
- * valid update and the offset at that time set to zero.
- * If following that we cruise outside the capture
- * range, assume a really bad frequency error and switch
- * to S_FREQ state.
- */
- case S_TSET:
- rstclock(S_FREQ);
- last_offset = clock_offset = fp_offset;
- return (0);
-
- /*
- * In S_SYNC state we ignore outlyers. At the first
- * outlyer after CLOCK_MINSTEP (900 s), switch to S_SPIK\v * state.
- */
- case S_SYNC:
- if (mu >= CLOCK_MINSTEP)
- rstclock(S_SPIK);
- return (0);
-
- /*
- * In S_FREQ state we ignore outlyers. At the first
- * outlyer after CLOCK_MINSTEP (900 s), compute the
- * apparent phase and frequency correction.
- */
- case S_FREQ:
- if (mu < CLOCK_MINSTEP)
- return (0);
- clock_frequency = (fp_offset - clock_offset) /
- mu;
- clock_offset = fp_offset;
- break;
-
- /*
- * In S_SPIK state a large correction is necessary.
- * Since the outlyer may be due to a large frequency
- * error, compute the apparent frequency correction.
- */
- case S_SPIK:
- clock_frequency = (fp_offset - clock_offset) /
- mu;
-
- /*
- * We get here directly in S_FSET state and indirectly
- * from S_SPIK state. The clock is either reset or
- * shaken, but never stirred.
- */
- default:
- if (allow_set_backward) {
- step_systime(fp_offset);
- NLOG(NLOG_SYNCEVENT|NLOG_SYSEVENT)
- msyslog(LOG_NOTICE, "time reset %.6f s",
- fp_offset);
- rstclock(S_TSET);
- retval = 1;
- } else {
- NLOG(NLOG_SYNCEVENT|NLOG_SYSEVENT)
- msyslog(LOG_NOTICE, "time slew %.6f s",
- fp_offset);
- rstclock(S_FREQ);
- last_offset = clock_offset = fp_offset;
- return (0);
- }
- break;
- }
- } else {
- switch (state) {
-
- /*
- * If this is the first update, initialize the
- * discipline parameters and pretend we had just set the
- * clock. We don't want to step the clock unless we have
- * to.
- */
- case S_FSET:
- rstclock(S_TSET);
- last_offset = clock_offset = fp_offset;
- return (0);
-
- /*
- * In S_FREQ state we ignore updates until CLOCK_MINSTEP
- * (900 s). 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;
- clock_offset = fp_offset;
- rstclock(S_SYNC);
- break;
-
- /*
- * Either the clock has just been set or the previous
- * update was a spike and ignored. Since this update is
- * not an outlyer, fold the tent and resume life.
- */
- case S_TSET:
- case S_SPIK:
- rstclock(S_SYNC);
-
- /*
- * We come here in the normal case for linear phase and
- * frequency adjustments. If the offset exceeds the
- * previous time error estimate by CLOCK_SGATE and the
- * interval since the last update is less than twice the
- * poll interval, consider the update a popcorn spike
- * and ignore it.
- */
- default:
- if (fabs(fp_offset - last_offset) >
- CLOCK_SGATE * oerror && mu <
- ULOGTOD(sys_poll + 1)) {
-#ifdef DEBUG
- if (debug)
- printf("local_clock: popcorn %.6f %.6f\n",
- fp_offset, last_offset);
-#endif
- last_offset = fp_offset;
- return (0);
- }
-
- /*
- * Compute the FLL and PLL frequency adjustments
- * conditioned on two weighting factors, one
- * which limits the time constant determined
- * from the Allan intercept, the other which
- * limits the gain factor as a function of
- * update interval. The net effect is to favor
- * the PLL adjustments at the smaller update
- * intervals and the FLL adjustments at the
- * larger ones.
- */
- dtemp = max(mu, allan_xpt);
- etemp = min(max(0, mu - CLOCK_MINSEC) /
- CLOCK_ALLAN, 1.);
- flladj = fp_offset * etemp / (dtemp *
- CLOCK_AVG);
- dtemp = ULOGTOD(SHIFT_PLL + 2 + sys_poll);
- plladj = fp_offset * mu / (dtemp * dtemp);
- clock_frequency = flladj + plladj;
- clock_offset = fp_offset;
- break;
- }
- }
-
- /*
- * 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.
- */
-#if defined(KERNEL_PLL)
- 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 drift file.
- */
- memset((char *)&ntv, 0, sizeof ntv);
- if (ext_enable) {
- ntv.modes = MOD_STATUS;
- } else {
- ntv.modes = MOD_BITS;
- if (clock_offset < 0)
- dtemp = -.5;
- else
- dtemp = .5;
-#ifdef STA_NANO
- if (pll_nano)
- ntv.offset = (int32)(clock_offset *
- 1e9 + dtemp);
- else
-#endif /* STA_NANO */
- ntv.offset = (int32)(clock_offset *
- 1e6 + dtemp);
-#ifdef STA_NANO
- ntv.constant = sys_poll;
-#else
- ntv.constant = sys_poll - 4;
-#endif /* STA_NANO */
-
- ntv.esterror = (u_int32)(sys_error * 1e6);
- ntv.maxerror = (u_int32)((sys_rootdelay / 2 +
- sys_rootdispersion) * 1e6);
- ntv.status = STA_PLL;
-
- /*
- * Set the leap bits in the status word.
- */
- if (sys_leap == LEAP_NOTINSYNC) {
- ntv.status |= STA_UNSYNC;
- } else if (calleapwhen(sys_reftime.l_ui) <
- CLOCK_DAY) {
- if (sys_leap & LEAP_ADDSECOND)
- ntv.status |= STA_INS;
- else if (sys_leap & LEAP_DELSECOND)
- ntv.status |= STA_DEL;
- }
-
- /*
- * Switch to FLL mode if the poll interval is
- * greater than MAXDPOLL, so that the kernel
- * loop behaves as the daemon loop; viz.,
- * selects the FLL when necessary, etc. For
- * legacy only.
- */
- if (sys_poll > NTP_MAXDPOLL)
- ntv.status |= STA_FLL;
- }
-
- /*
- * Wiggle the PPS bits according to the health of the
- * prefer peer.
- */
- if (pll_status & STA_PPSSIGNAL)
- ntv.status |= STA_PPSFREQ;
- if (pll_status & STA_PPSFREQ && pps_update)
- ntv.status |= STA_PPSTIME;
-
- /*
- * Update the offset and frequency from the kernel
- * variables.
- */
- if (ntp_adjtime(&ntv) == TIME_ERROR) {
- if (ntv.status != pll_status)
- msyslog(LOG_ERR,
- "kernel pll status change %x",
- ntv.status);
- }
- pll_status = ntv.status;
-#ifdef STA_NANO
- if (pll_nano)
- clock_offset = ntv.offset / 1e9;
- else
-#endif /* STA_NANO */
- clock_offset = ntv.offset / 1e6;
-#ifdef STA_NANO
- sys_poll = ntv.constant;
-#else
- sys_poll = ntv.constant + 4;
-#endif /* STA_NANO */
- clock_frequency = ntv.freq / 65536e6 - drift_comp;
-
- /*
- * If the kernel pps discipline is working, monitor its
- * performance.
- */
- if (ntv.status & STA_PPSTIME) {
- if (!pps_control)
- NLOG(NLOG_SYSEVENT)msyslog(LOG_INFO,
- "pps sync enabled");
- pps_control = current_time;
-#ifdef STA_NANO
- if (pll_nano)
- record_peer_stats(
- &loopback_interface->sin,
- ctlsysstatus(), ntv.offset / 1e9,
- 0., ntv.jitter / 1e9, 0.);
- else
-#endif /* STA_NANO */
- record_peer_stats(
- &loopback_interface->sin,
- ctlsysstatus(), ntv.offset / 1e6,
- 0., ntv.jitter / 1e6, 0.);
- }
- }
-#endif /* KERNEL_PLL */
-
- /*
- * Adjust the clock frequency and calculate the stability. If
- * kernel support is available, we use the results of the kernel
- * discipline instead of the PLL/FLL discipline. In this case,
- * drift_comp is a sham and used only for updating the drift
- * file and for billboard eye candy.
- */
- drift_comp += clock_frequency;
- if (drift_comp > sys_maxfreq)
- drift_comp = sys_maxfreq;
- else if (drift_comp <= -sys_maxfreq)
- drift_comp = -sys_maxfreq;
- dtemp = SQUARE(clock_stability);
- etemp = SQUARE(clock_frequency) - dtemp;
- clock_stability = SQRT(dtemp + etemp / CLOCK_AVG);
- allan_xpt = max(CLOCK_ALLAN, clock_stability * CLOCK_ADF);
-
- /*
- * In SYNC state, adjust the poll interval.
- */
- if (state == S_SYNC) {
- if (clock_stability < CLOCK_MAXSTAB &&
- fabs(clock_offset) < CLOCK_PGATE * sys_error) {
- 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--;
- }
- }
- }
- }
-
- /*
- * Update the system time variables.
- */
- last_time = current_time;
- last_offset = clock_offset;
- dtemp = peer->disp + SQRT(peer->variance + SQUARE(sys_error));
- if ((peer->flags & FLAG_REFCLOCK) == 0 && dtemp < MINDISPERSE)
- dtemp = MINDISPERSE;
- sys_rootdispersion = peer->rootdispersion + dtemp;
- (void)record_loop_stats();
-#ifdef DEBUG
- if (debug)
- printf(
- "local_clock: mu %.0f allan %.0f fadj %.3f fll %.3f pll %.3f\n",
- mu, allan_xpt, clock_frequency * 1e6, flladj * 1e6,
- plladj * 1e6);
-#endif /* DEBUG */
-#ifdef DEBUG
- if (debug)
- printf(
- "local_clock: jitter %.6f freq %.3f stab %.3f poll %d count %d\n",
- sys_error, drift_comp * 1e6, clock_stability * 1e6,
- sys_poll, tc_counter);
-#endif /* DEBUG */
- return (retval);
-}
-
-
-/*
- * adj_host_clock - Called once every second to update the local clock.
- */
-void
-adj_host_clock(
- void
- )
-{
- double adjustment;
-
- /*
- * 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. Note we do this even with
- * external clocks, since the clock driver will recompute the
- * maximum error and the local clock driver will pick it up and
- * pass to the common refclock routines. Very elegant.
- */
- sys_rootdispersion += CLOCK_PHI;
-
- /*
- * Declare PPS kernel unsync if the pps signal has not been
- * heard for a few minutes.
- */
- if (pps_control && current_time - pps_control > PPS_MAXAGE) {
- if (pps_control)
- NLOG(NLOG_SYSEVENT) /* conditional if clause */
- msyslog(LOG_INFO, "pps sync disabled");
- pps_control = 0;
- }
- if (!ntp_enable)
- return;
-
- /*
- * If the phase-lock loop is implemented in the kernel, we
- * have no business going further.
- */
- if (pll_control && kern_enable)
- return;
-
- /*
- * Intricate wrinkle for legacy only. If the local clock driver
- * is in use and selected for synchronization, somebody else may
- * tinker the adjtime() syscall. If this is the case, the driver
- * is marked prefer and we have to avoid calling adjtime(),
- * since that may truncate the other guy's requests.
- */
- if (sys_peer != 0) {
- if (sys_peer->refclktype == REFCLK_LOCALCLOCK &&
- sys_peer->flags & FLAG_PREFER)
- return;
- }
- adjustment = clock_offset / ULOGTOD(SHIFT_PLL + sys_poll);
- clock_offset -= adjustment;
- adj_systime(adjustment + drift_comp);
-}
-
-
-/*
- * Clock state machine. Enter new state and set state variables.
- */
-static void
-rstclock(
- int trans /* new state */
- )
-{
- state = trans;
- switch (state) {
-
- /*
- * Frequency mode. The clock has ben set, but the frequency has
- * not yet been determined. Note that the Allan intercept is set
- * insure the clock filter considers only the most recent
- * measurements.
- */
- case S_FREQ:
- sys_poll = NTP_MINDPOLL;
- allan_xpt = CLOCK_ALLAN;
- last_time = current_time;
- break;
-
- /*
- * Synchronized mode. Discipline the poll interval.
- */
- case S_SYNC:
- sys_poll = NTP_MINDPOLL;
- allan_xpt = CLOCK_ALLAN;
- tc_counter = 0;
- break;
-
- /*
- * Don't do anything in S_SPIK state; just continue from S_SYNC
- * state.
- */
- case S_SPIK:
- break;
-
- /*
- * S_NSET, S_FSET and S_TSET states. These transient states set
- * the time reference for future frequency updates.
- */
- default:
- sys_poll = NTP_MINDPOLL;
- allan_xpt = CLOCK_ALLAN;
- last_time = current_time;
- last_offset = clock_offset = 0;
- break;
- }
-}
-
-
-/*
- * loop_config - configure the loop filter
- */
-void
-loop_config(
- int item,
- double freq
- )
-{
-#if defined(KERNEL_PLL)
- struct timex ntv;
-#endif /* KERNEL_PLL */
-
-#ifdef DEBUG
- if (debug)
- printf("loop_config: state %d freq %.3f\n", item, freq *
- 1e6);
-#endif
- switch (item) {
-
- case LOOP_DRIFTINIT:
- case LOOP_DRIFTCOMP:
-
- /*
- * The drift file is present and the initial frequency
- * is available, so set the state to S_FSET
- */
- rstclock(S_FSET);
- drift_comp = freq;
- if (drift_comp > sys_maxfreq)
- drift_comp = sys_maxfreq;
- if (drift_comp < -sys_maxfreq)
- drift_comp = -sys_maxfreq;
-#ifdef KERNEL_PLL
- /*
- * If the phase-lock code is implemented in the kernel,
- * give the time_constant and saved frequency offset to
- * the kernel. If not, no harm is done. Note the initial
- * time constant is zero, but the first clock update
- * will fix that.
- */
- memset((char *)&ntv, 0, sizeof ntv);
- pll_control = 1;
-#ifdef MOD_NANO
- ntv.modes = MOD_NANO;
-#endif /* MOD_NANO */
-#ifdef SIGSYS
- newsigsys.sa_handler = pll_trap;
- newsigsys.sa_flags = 0;
- if (sigaction(SIGSYS, &newsigsys, &sigsys)) {
- msyslog(LOG_ERR,
- "sigaction() fails to save SIGSYS trap: %m");
- pll_control = 0;
- return;
- }
-
- /*
- * Use sigsetjmp() to save state and then call
- * ntp_adjtime(); if it fails, then siglongjmp() is used
- * to return control
- */
- if (sigsetjmp(env, 1) == 0)
- (void)ntp_adjtime(&ntv);
- if ((sigaction(SIGSYS, &sigsys,
- (struct sigaction *)NULL))) {
- msyslog(LOG_ERR,
- "sigaction() fails to restore SIGSYS trap: %m");
- pll_control = 0;
- return;
- }
-#else /* SIGSYS */
- if (ntp_adjtime(&ntv) < 0) {
- msyslog(LOG_ERR,
- "loop_config: ntp_adjtime() failed: %m");
- pll_control = 0;
- }
-#endif /* SIGSYS */
-
- /*
- * If the kernel support is available and enabled,
- * initialize the parameters, but only if the external
- * clock is not present.
- */
- if (pll_control && kern_enable) {
- msyslog(LOG_NOTICE,
- "using kernel phase-lock loop %04x",
- ntv.status);
-#ifdef STA_NANO
- if (ntv.status & STA_NANO)
- pll_nano = 1;
-#endif /* STA_NANO */
-#ifdef STA_CLK
-
- if (ntv.status & STA_CLK) {
- ext_enable = 1;
- } else {
- ntv.modes = MOD_BITS | MOD_FREQUENCY;
- ntv.freq = (int32)(drift_comp *
- 65536e6);
- ntv.maxerror = MAXDISPERSE;
- ntv.esterror = MAXDISPERSE;
- ntv.status = STA_UNSYNC | STA_PLL;
- (void)ntp_adjtime(&ntv);
- }
-#else
- ntv.modes = MOD_BITS | MOD_FREQUENCY;
- ntv.freq = (int32)(5536e6);
- ntv.maxerror = MAXDISPERSE;
- ntv.esterror = MAXDISPERSE;
- ntv.status = STA_UNSYNC | STA_PLL;
- (void)ntp_adjtime(&ntv);
-#endif /* STA_CLK */
- }
-#endif /* KERNEL_PLL */
- }
-}
-
-
-#if defined(KERNEL_PLL) && defined(SIGSYS)
-/*
- * _trap - trap processor for undefined syscalls
- *
- * This nugget is called by the kernel when the SYS_ntp_adjtime()
- * syscall bombs because the silly thing has not been implemented in
- * the kernel. In this case the phase-lock loop is emulated by
- * the stock adjtime() syscall and a lot of indelicate abuse.
- */
-RETSIGTYPE
-pll_trap(
- int arg
- )
-{
- pll_control = 0;
- siglongjmp(env, 1);
-}
-#endif /* KERNEL_PLL && SIGSYS */
projects / thirdparty / ntp.git / commitdiff
