/* * 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 */