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Diffstat (limited to 'ntpd/refclock_local.c')
| -rw-r--r-- | ntpd/refclock_local.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/ntpd/refclock_local.c b/ntpd/refclock_local.c new file mode 100644 index 0000000..d1b2871 --- /dev/null +++ b/ntpd/refclock_local.c @@ -0,0 +1,230 @@ + +/* + * refclock_local - local pseudo-clock driver + * + * wjm 17-aug-1995: add a hook for special treatment of VMS_LOCALUNIT + */ +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#ifdef REFCLOCK + +#include "ntpd.h" +#include "ntp_refclock.h" +#include "ntp_stdlib.h" + +#include <stdio.h> +#include <ctype.h> + +#ifdef KERNEL_PLL +#include "ntp_syscall.h" +#endif + +/* + * This is a hack to allow a machine to use its own system clock as a + * reference clock, i.e., to free-run using no outside clock discipline + * source. Note that the clock selection algorithm will not select this + * driver unless all other sources of synchronization have been lost. + * This is useful if you want to use NTP in an isolated environment + * with no radio clock or NIST modem available. Pick a machine that you + * figure has a good clock oscillator and configure it with this + * driver. Set the clock using the best means available, like + * eyeball-and-wristwatch. Then, point all the other machines at this + * one or use broadcast (not multicast) mode to distribute time. + * + * Another application for this driver is if you want to use a + * particular server's clock as the clock of last resort when all other + * normal synchronization sources have gone away. This is especially + * useful if that server has an ovenized oscillator. However, the + * preferred was to do this is using orphan mode. See the documentation. + * + * A third application for this driver is when an external discipline + * source is available, such as the NIST "lockclock" program, which + * synchronizes the local clock via a telephone modem and the NIST + * Automated Computer Time Service (ACTS), or the Digital Time + * Synchronization Service (DTSS), which runs on DCE machines. In this + * case the stratum should be set at zero, indicating a bona fide + * stratum-1 source. Exercise some caution with this, since there is no + * easy way to telegraph via NTP that something might be wrong in the + * discipline source itself. In the case of DTSS, the local clock can + * have a rather large jitter, depending on the interval between + * corrections and the intrinsic frequency error of the clock + * oscillator. In extreme cases, this can cause clients to exceed the + * 128-ms slew window and drop off the NTP subnet. + * + * Fudge Factors + * + * If fudge flag1 is lit, the leap second bit is set in the peer + * status word. It should be set early in the day of a leap second + * event and set dark on the day after the event. + * + * Note the fudge time1 and time2 have been deprecated. The fudge time1 + * was intended to apply a bias offset. This can be done using the Unix + * date command. The fudge time2 was intended to apply a bias frequency. + * This can be done using the frequency file and/or the freq + * configuration command. + */ +/* + * Local interface definitions + */ +#define PRECISION (-7) /* about 10 ms precision */ +#define DESCRIPTION "Undisciplined local clock" /* WRU */ +#define STRATUM 5 /* default stratum */ +#define DISPERSION .01 /* default dispersion (10 ms) */ + +/* + * Imported from the timer module + */ +extern u_long current_time; + +/* + * Imported from ntp_proto + */ +extern s_char sys_precision; + +/* + * Function prototypes + */ +static int local_start (int, struct peer *); +static void local_poll (int, struct peer *); + +/* + * Local variables + */ +static u_long poll_time; /* last time polled */ + +/* + * Transfer vector + */ +struct refclock refclock_local = { + local_start, /* start up driver */ + noentry, /* shut down driver (not used) */ + local_poll, /* transmit poll message */ + noentry, /* not used (old lcl_control) */ + noentry, /* initialize driver (not used) */ + noentry, /* not used (old lcl_buginfo) */ + NOFLAGS /* not used */ +}; + + +/* + * local_start - start up the clock + */ +static int +local_start( + int unit, + struct peer *peer + ) +{ + struct refclockproc *pp; + + pp = peer->procptr; + + /* + * Initialize miscellaneous variables + */ + peer->precision = sys_precision; + pp->leap = LEAP_NOTINSYNC; + peer->stratum = STRATUM; + pp->stratum = STRATUM; + pp->clockdesc = DESCRIPTION; + memcpy(&pp->refid, "LOCL", 4); + poll_time = current_time; + return (1); +} + + +/* + * local_poll - called by the transmit procedure + * + * LOCKCLOCK: If the kernel supports the nanokernel or microkernel + * system calls, the leap bits are extracted from the kernel. If there + * is a kernel error or the kernel leap bits are set to 11, the NTP leap + * bits are set to 11 and the stratum is set to infinity. Otherwise, the + * NTP leap bits are set to the kernel leap bits and the stratum is set + * as fudged. This behavior does not faithfully follow the + * specification, but is probably more appropriate in a multiple-server + * national laboratory network. + */ +static void +local_poll( + int unit, + struct peer *peer + ) +{ +#if defined(KERNEL_PLL) && defined(LOCKCLOCK) + struct timex ntv; +#endif /* KERNEL_PLL LOCKCLOCK */ + struct refclockproc *pp; + + /* + * Do no evil unless the house is dark or lit with our own lamp. + */ + if (!(sys_peer == NULL || sys_peer == peer)) + return; + +#if defined(VMS) && defined(VMS_LOCALUNIT) + if (unit == VMS_LOCALUNIT) { + extern void vms_local_poll(struct peer *); + + vms_local_poll(peer); + return; + } +#endif /* VMS && VMS_LOCALUNIT */ + + pp = peer->procptr; + pp->polls++; + + /* + * Ramble through the usual filtering and grooming code, which + * is essentially a no-op and included mostly for pretty + * billboards. We allow a one-time time adjustment using fudge + * time1 (s) and a continuous frequency adjustment using fudge + * time 2 (ppm). + */ + poll_time = current_time; + refclock_process_offset(pp, pp->lastrec, pp->lastrec, 0); + + /* + * If another process is disciplining the system clock, we set + * the leap bits and quality indicators from the kernel. + */ +#if defined(KERNEL_PLL) && defined(LOCKCLOCK) + memset(&ntv, 0, sizeof ntv); + switch (ntp_adjtime(&ntv)) { + case TIME_OK: + pp->leap = LEAP_NOWARNING; + peer->stratum = pp->stratum; + break; + + case TIME_INS: + pp->leap = LEAP_ADDSECOND; + peer->stratum = pp->stratum; + break; + + case TIME_DEL: + pp->leap = LEAP_DELSECOND; + peer->stratum = pp->stratum; + break; + + default: + pp->leap = LEAP_NOTINSYNC; + peer->stratum = STRATUM_UNSPEC; + } + pp->disp = 0; + pp->jitter = 0; +#else /* KERNEL_PLL LOCKCLOCK */ + if (pp->sloppyclockflag & CLK_FLAG1) + pp->leap = LEAP_ADDSECOND; + else + pp->leap = LEAP_NOWARNING; + pp->disp = DISPERSION; + pp->jitter = 0; +#endif /* KERNEL_PLL LOCKCLOCK */ + pp->lastref = pp->lastrec; + refclock_receive(peer); +} +#else +int refclock_local_bs; +#endif /* REFCLOCK */ |