/*

 * 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

 *

 * None currently supported.

 */

/*

 * 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.

   */

  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 */

  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 */