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Diffstat (limited to 'contrib/ntp/ntpd/refclock_local.c')
| -rw-r--r-- | contrib/ntp/ntpd/refclock_local.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/contrib/ntp/ntpd/refclock_local.c b/contrib/ntp/ntpd/refclock_local.c new file mode 100644 index 0000000..12184db --- /dev/null +++ b/contrib/ntp/ntpd/refclock_local.c @@ -0,0 +1,258 @@ +/* wjm 17-aug-1995: add a hook for special treatment of VMS_LOCALUNIT */ + +/* + * refclock_local - local pseudo-clock driver + */ +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#ifdef REFCLOCK +#include <stdio.h> +#include <ctype.h> +#include <sys/time.h> + +#include "ntpd.h" +#include "ntp_refclock.h" +#include "ntp_stdlib.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. 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. For this you would + * configure this driver at a higher stratum (say 3 or 4) to prevent the + * server's stratum from falling below that. + * + * 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. + * + * THis driver includes provisions to telegraph synchronization state + * and related variables by means of kernel variables with specially + * modified kernels. This is done using the ntp_adjtime() syscall. + * In the cases where another protocol or device synchronizes the local + * host, the data given to the kernel can be slurped up by this driver + * and distributed to clients by ordinary NTP messaging. + * + * In the default mode the behavior of the clock selection algorithm is + * modified when this driver is in use. The algorithm is designed so + * that this driver will never be selected unless no other discipline + * source is available. This can be overriden with the prefer keyword of + * the server configuration command, in which case only this driver will + * be selected for synchronization and all other discipline sources will + * be ignored. This behavior is intended for use when an external + * discipline source controls the system clock. + * + * Fudge Factors + * + * The stratum for this driver set at 3 by default, but it can be changed + * by the fudge command and/or the ntpdc utility. The reference ID is + * "LCL" by default, but can be changed using the same mechanism. *NEVER* + * configure this driver to operate at a stratum which might possibly + * disrupt a client with access to a bona fide primary server, unless the + * local clock oscillator is reliably disciplined by another source. + * *NEVER NEVER* configure a server which might devolve to an undisciplined + * local clock to use multicast mode. Always remember that an improperly + * configured local clock driver let loose in the Internet can cause + * very serious disruption. This is why most of us who care about good + * time use cryptographic authentication. + * + * This driver provides a mechanism to trim the local clock in both time + * and frequency, as well as a way to manipulate the leap bits. The + * fudge time1 parameter adjusts the time, in seconds, and the fudge + * time2 parameter adjusts the frequency, in ppm. The fudge time1 parameter + * is additive; that is, it adds an increment to the current time. The + * fudge time2 parameter directly sets the frequency. + */ + +/* + * Local interface definitions + */ +#define PRECISION (-7) /* about 10 ms precision */ +#define REFID "LCL\0" /* reference ID */ +#define DESCRIPTION "Undisciplined local clock" /* WRU */ + +#define STRATUM 3 /* 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; + +#ifdef KERNEL_PLL +/* + * Imported from ntp_loopfilter + */ +extern int pll_control; /* kernel pll control */ +extern int kern_enable; /* kernel pll enabled */ +extern int ext_enable; /* external clock enable */ +#endif /* KERNEL_PLL */ + +/* + * Function prototypes + */ +static int local_start P((int, struct peer *)); +static void local_poll P((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; + peer->stratum = STRATUM; + pp->clockdesc = DESCRIPTION; + memcpy((char *)&pp->refid, REFID, 4); +#if defined(VMS) && defined(VMS_LOCALUNIT) + /* provide a non-standard REFID */ + if(unit == VMS_LOCALUNIT) + memcpy((char *)&pp->refid,"LCLv",4); +#endif /* VMS && VMS_LOCALUNIT */ + poll_time = current_time; + return (1); +} + + +/* + * local_poll - called by the transmit procedure + */ +static void +local_poll( + int unit, + struct peer *peer + ) +{ + struct refclockproc *pp; +#if defined(KERNEL_PLL) && defined(STA_CLK) + struct timex ntv; + int retval; +#endif /* KERNEL_PLL STA_CLK */ + +#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). + */ + get_systime(&pp->lastrec); + pp->fudgetime1 += pp->fudgetime2 * 1e-6 * (current_time - + poll_time); + poll_time = current_time; + refclock_process_offset(pp, pp->lastrec, pp->lastrec, pp->fudgetime1); + pp->leap = LEAP_NOWARNING; + pp->disp = DISPERSION; + pp->variance = 0; +#if defined(KERNEL_PLL) && defined(STA_CLK) + + /* + * If the kernel pll code is up and running, somebody else + * may come diddle the clock. If so, they better use ntp_adjtime(), + * and set the STA_CLK bit in the status word. In this case, the + * performance information is read from the kernel and becomes the + * variables presented to the clock mitigation process. + */ + if (pll_control && kern_enable && (peer->flags & FLAG_PREFER)) { + memset((char *)&ntv, 0, sizeof ntv); + retval = ntp_adjtime(&ntv); + if (ntv.status & STA_CLK) { + ext_enable = 1; + switch(retval) { + + case TIME_OK: + pp->leap = LEAP_NOWARNING; + break; + + case TIME_INS: + pp->leap = LEAP_ADDSECOND; + break; + + case TIME_DEL: + pp->leap = LEAP_DELSECOND; + break; + + case TIME_ERROR: + pp->leap = LEAP_NOTINSYNC; + } + pp->disp = ntv.maxerror / 1e6; + pp->variance = SQUARE(ntv.esterror / 1e6); + } + } else { + ext_enable = 0; + } +#endif /* KERNEL_PLL STA_CLK */ + refclock_receive(peer); + pp->fudgetime1 = 0; +} +#endif /* REFCLOCK */ |
