Expand PMF_FN_* macros.

[netbsd-mini2440.git] / dist / ntp / ntpd / refclock_datum.c

/*      $NetBSD: refclock_datum.c,v 1.3 2006/03/19 07:20:30 kardel Exp $        */

/*
** refclock_datum - clock driver for the Datum Programmable Time Server
**
** Important note: This driver assumes that you have termios. If you have
** a system that does not have termios, you will have to modify this driver.
**
** Sorry, I have only tested this driver on SUN and HP platforms.
*/

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#if defined(REFCLOCK) && defined(CLOCK_DATUM)

/*
** Include Files
*/

#include "ntpd.h"
#include "ntp_io.h"
#include "ntp_refclock.h"
#include "ntp_unixtime.h"
#include "ntp_stdlib.h"

#include <stdio.h>
#include <ctype.h>

#if defined(HAVE_BSD_TTYS)
#include <sgtty.h>
#endif /* HAVE_BSD_TTYS */

#if defined(HAVE_SYSV_TTYS)
#include <termio.h>
#endif /* HAVE_SYSV_TTYS */

#if defined(HAVE_TERMIOS)
#include <termios.h>
#endif
#if defined(STREAM)
#include <stropts.h>
#if defined(WWVBCLK)
#include <sys/clkdefs.h>
#endif /* WWVBCLK */
#endif /* STREAM */

#include "ntp_stdlib.h"

/*
** This driver supports the Datum Programmable Time System (PTS) clock.
** The clock works in very straight forward manner. When it receives a
** time code request (e.g., the ascii string "//k/mn"), it responds with
** a seven byte BCD time code. This clock only responds with a
** time code after it first receives the "//k/mn" message. It does not
** periodically send time codes back at some rate once it is started.
** the returned time code can be broken down into the following fields.
**
**            _______________________________
** Bit Index | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
**            ===============================
** byte 0:   | -   -   -   - |      H D      |
**            ===============================
** byte 1:   |      T D      |      U D      |
**            ===============================
** byte 2:   | -   - |  T H  |      U H      |
**            ===============================
** byte 3:   | - |    T M    |      U M      |
**            ===============================
** byte 4:   | - |    T S    |      U S      |
**            ===============================
** byte 5:   |      t S      |      h S      |
**            ===============================
** byte 6:   |      m S      | -   -   -   - |
**            ===============================
**
** In the table above:
**
**      "-" means don't care
**      "H D", "T D", and "U D" means Hundreds, Tens, and Units of Days
**      "T H", and "UH" means Tens and Units of Hours
**      "T M", and "U M" means Tens and Units of Minutes
**      "T S", and "U S" means Tens and Units of Seconds
**      "t S", "h S", and "m S" means tenths, hundredths, and thousandths
**                              of seconds
**
** The Datum PTS communicates throught the RS232 port on your machine.
** Right now, it assumes that you have termios. This driver has been tested
** on SUN and HP workstations. The Datum PTS supports various IRIG and
** NASA input codes. This driver assumes that the name of the device is
** /dev/datum. You will need to make a soft link to your RS232 device or
** create a new driver to use this refclock.
*/

/*
** Datum PTS defines
*/

/*
** Note that if GMT is defined, then the Datum PTS must use Greenwich
** time. Otherwise, this driver allows the Datum PTS to use the current
** wall clock for its time. It determines the time zone offset by minimizing
** the error after trying several time zone offsets. If the Datum PTS
** time is Greenwich time and GMT is not defined, everything should still
** work since the time zone will be found to be 0. What this really means
** is that your system time (at least to start with) must be within the
** correct time by less than +- 30 minutes. The default is for GMT to not
** defined. If you really want to force GMT without the funny +- 30 minute
** stuff then you must define (uncomment) GMT below.
*/

/*
#define GMT
#define DEBUG_DATUM_PTC
#define LOG_TIME_ERRORS
*/


#define PRECISION       (-10)           /* precision assumed 1/1024 ms */
#define REFID "DATM"                    /* reference id */
#define DATUM_DISPERSION 0              /* fixed dispersion = 0 ms */
#define DATUM_MAX_ERROR 0.100           /* limits on sigma squared */
#define DATUM_DEV       "/dev/datum"    /* device name */

#define DATUM_MAX_ERROR2 (DATUM_MAX_ERROR*DATUM_MAX_ERROR)

/*
** The Datum PTS structure
*/

/*
** I don't use a fixed array of MAXUNITS like everyone else just because
** I don't like to program that way. Sorry if this bothers anyone. I assume
** that you can use any id for your unit and I will search for it in a
** dynamic array of units until I find it. I was worried that users might
** enter a bad id in their configuration file (larger than MAXUNITS) and
** besides, it is just cleaner not to have to assume that you have a fixed
** number of anything in a program.
*/

struct datum_pts_unit {
        struct peer *peer;              /* peer used by ntp */
        struct refclockio io;           /* io structure used by ntp */
        int PTS_fd;                     /* file descriptor for PTS */
        u_int unit;                     /* id for unit */
        u_long timestarted;             /* time started */
        l_fp lastrec;                   /* time tag for the receive time (system) */
        l_fp lastref;                   /* reference time (Datum time) */
        u_long yearstart;               /* the year that this clock started */
        int coderecv;                   /* number of time codes received */
        int day;                        /* day */
        int hour;                       /* hour */
        int minute;                     /* minutes */
        int second;                     /* seconds */
        int msec;                       /* miliseconds */
        int usec;                       /* miliseconds */
        u_char leap;                    /* funny leap character code */
        char retbuf[8];         /* returned time from the datum pts */
        char nbytes;                    /* number of bytes received from datum pts */ 
        double sigma2;          /* average squared error (roughly) */
        int tzoff;                      /* time zone offest from GMT */
};

/*
** PTS static constant variables for internal use
*/

static char TIME_REQUEST[6];    /* request message sent to datum for time */
static int nunits;              /* number of active units */
static struct datum_pts_unit
**datum_pts_unit;       /* dynamic array of datum PTS structures */

/*
** Callback function prototypes that ntpd needs to know about.
*/

static  int     datum_pts_start         P((int, struct peer *));
static  void    datum_pts_shutdown      P((int, struct peer *));
static  void    datum_pts_poll          P((int, struct peer *));
static  void    datum_pts_control       P((int, struct refclockstat *,
                                           struct refclockstat *, struct peer *));
static  void    datum_pts_init          P((void));
static  void    datum_pts_buginfo       P((int, struct refclockbug *, struct peer *));

/*
** This is the call back function structure that ntpd actually uses for
** this refclock.
*/

struct  refclock refclock_datum = {
        datum_pts_start,                /* start up a new Datum refclock */
        datum_pts_shutdown,             /* shutdown a Datum refclock */
        datum_pts_poll,         /* sends out the time request */
        datum_pts_control,              /* not used */
        datum_pts_init,         /* initialization (called first) */
        datum_pts_buginfo,              /* not used */
        NOFLAGS                 /* we are not setting any special flags */
};

/*
** The datum_pts_receive callback function is handled differently from the
** rest. It is passed to the ntpd io data structure. Basically, every
** 64 seconds, the datum_pts_poll() routine is called. It sends out the time
** request message to the Datum Programmable Time System. Then, ntpd
** waits on a select() call to receive data back. The datum_pts_receive()
** function is called as data comes back. We expect a seven byte time
** code to be returned but the datum_pts_receive() function may only get
** a few bytes passed to it at a time. In other words, this routine may
** get called by the io stuff in ntpd a few times before we get all seven
** bytes. Once the last byte is received, we process it and then pass the
** new time measurement to ntpd for updating the system time. For now,
** there is no 3 state filtering done on the time measurements. The
** jitter may be a little high but at least for its current use, it is not
** a problem. We have tried to keep things as simple as possible. This
** clock should not jitter more than 1 or 2 mseconds at the most once
** things settle down. It is important to get the right drift calibrated
** in the ntpd.drift file as well as getting the right tick set up right
** using tickadj for SUNs. Tickadj is not used for the HP but you need to
** remember to bring up the adjtime daemon because HP does not support
** the adjtime() call.
*/

static  void    datum_pts_receive       P((struct recvbuf *));

/*......................................................................*/
/*      datum_pts_start - start up the datum PTS. This means open the   */
/*      RS232 device and set up the data structure for my unit.         */
/*......................................................................*/

static int
datum_pts_start(
        int unit,
        struct peer *peer
        )
{
        struct datum_pts_unit **temp_datum_pts_unit;
        struct datum_pts_unit *datum_pts;
        int fd;
#ifdef HAVE_TERMIOS
        struct termios arg;
#endif

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Starting Datum PTS unit %d\n", unit);
#endif

        /*
        ** Open the Datum PTS device
        */
        fd = open(DATUM_DEV, O_RDWR);

        if (fd < 0) {
                msyslog(LOG_ERR, "Datum_PTS: open(\"%s\", O_RDWR) failed: %m", DATUM_DEV);
                return 0;
        }

        /*
        ** Create the memory for the new unit
        */

        temp_datum_pts_unit = (struct datum_pts_unit **)
                malloc((nunits+1)*sizeof(struct datum_pts_unit *));
        if (nunits > 0) memcpy(temp_datum_pts_unit, datum_pts_unit,
                               nunits*sizeof(struct datum_pts_unit *));
        free(datum_pts_unit);
        datum_pts_unit = temp_datum_pts_unit;
        datum_pts_unit[nunits] = (struct datum_pts_unit *)
                malloc(sizeof(struct datum_pts_unit));
        datum_pts = datum_pts_unit[nunits];

        datum_pts->unit = unit; /* set my unit id */
        datum_pts->yearstart = 0;       /* initialize the yearstart to 0 */
        datum_pts->sigma2 = 0.0;        /* initialize the sigma2 to 0 */

        datum_pts->PTS_fd = fd;

        fcntl(datum_pts->PTS_fd, F_SETFL, 0); /* clear the descriptor flags */

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Opening RS232 port with file descriptor %d\n",
                   datum_pts->PTS_fd);
#endif

        /*
        ** Set up the RS232 terminal device information. Note that we assume that
        ** we have termios. This code has only been tested on SUNs and HPs. If your
        ** machine does not have termios this driver cannot be initialized. You can change this
        ** if you want by editing this source. Please give the changes back to the
        ** ntp folks so that it can become part of their regular distribution.
        */

#ifdef HAVE_TERMIOS

        arg.c_iflag = IGNBRK;
        arg.c_oflag = 0;
        arg.c_cflag = B9600 | CS8 | CREAD | PARENB | CLOCAL;
        arg.c_lflag = 0;
        arg.c_cc[VMIN] = 0;             /* start timeout timer right away (not used) */
        arg.c_cc[VTIME] = 30;           /* 3 second timout on reads (not used) */

        tcsetattr(datum_pts->PTS_fd, TCSANOW, &arg);

#else

        msyslog(LOG_ERR, "Datum_PTS: Termios not supported in this driver");
        (void)close(datum_pts->PTS_fd);

        peer->precision = PRECISION;
        pp->clockdesc = DESCRIPTION;
        memcpy((char *)&pp->refid, REFID, 4);

        return 0;

#endif

        /*
        ** Initialize the ntpd IO structure
        */

        datum_pts->peer = peer;
        datum_pts->io.clock_recv = datum_pts_receive;
        datum_pts->io.srcclock = (caddr_t)datum_pts;
        datum_pts->io.datalen = 0;
        datum_pts->io.fd = datum_pts->PTS_fd;

        if (!io_addclock(&(datum_pts->io))) {

#ifdef DEBUG_DATUM_PTC
                if (debug)
                    printf("Problem adding clock\n");
#endif

                msyslog(LOG_ERR, "Datum_PTS: Problem adding clock");
                (void)close(datum_pts->PTS_fd);

                return 0;
        }

        /*
        ** Now add one to the number of units and return a successful code
        */

        nunits++;
        return 1;

}


/*......................................................................*/
/*      datum_pts_shutdown - this routine shuts doen the device and     */
/*      removes the memory for the unit.                                */
/*......................................................................*/

static void
datum_pts_shutdown(
        int unit,
        struct peer *peer
        )
{
        int i,j;
        struct datum_pts_unit **temp_datum_pts_unit;

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Shutdown Datum PTS\n");
#endif

        msyslog(LOG_ERR, "Datum_PTS: Shutdown Datum PTS");

        /*
        ** First we have to find the right unit (i.e., the one with the same id).
        ** We do this by looping through the dynamic array of units intil we find
        ** it. Note, that I don't simply use an array with a maximimum number of
        ** Datum PTS units. Everything is completely dynamic.
        */

        for (i=0; i<nunits; i++) {
                if (datum_pts_unit[i]->unit == unit) {

                        /*
                        ** We found the unit so close the file descriptor and free up the memory used
                        ** by the structure.
                        */

                        io_closeclock(&datum_pts_unit[i]->io);
                        close(datum_pts_unit[i]->PTS_fd);
                        free(datum_pts_unit[i]);

                        /*
                        ** Now clean up the datum_pts_unit dynamic array so that there are no holes.
                        ** This may mean moving pointers around, etc., to keep things compact.
                        */

                        if (nunits > 1) {

                                temp_datum_pts_unit = (struct datum_pts_unit **)
                                        malloc((nunits-1)*sizeof(struct datum_pts_unit *));
                                if (i!= 0) memcpy(temp_datum_pts_unit, datum_pts_unit,
                                                  i*sizeof(struct datum_pts_unit *));

                                for (j=i+1; j<nunits; j++) {
                                        temp_datum_pts_unit[j-1] = datum_pts_unit[j];
                                }

                                free(datum_pts_unit);
                                datum_pts_unit = temp_datum_pts_unit;

                        }else{

                                free(datum_pts_unit);
                                datum_pts_unit = NULL;

                        }

                        return;

                }
        }

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Error, could not shut down unit %d\n",unit);
#endif

        msyslog(LOG_ERR, "Datum_PTS: Could not shut down Datum PTS unit %d",unit);

}

/*......................................................................*/
/*      datum_pts_poll - this routine sends out the time request to the */
/*      Datum PTS device. The time will be passed back in the           */
/*      datum_pts_receive() routine.                                    */
/*......................................................................*/

static void
datum_pts_poll(
        int unit,
        struct peer *peer
        )
{
        int i;
        int unit_index;
        int error_code;
        struct datum_pts_unit *datum_pts;

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Poll Datum PTS\n");
#endif

        /*
        ** Find the right unit and send out a time request once it is found.
        */

        unit_index = -1;
        for (i=0; i<nunits; i++) {
                if (datum_pts_unit[i]->unit == unit) {
                        unit_index = i;
                        datum_pts = datum_pts_unit[i];
                        error_code = write(datum_pts->PTS_fd, TIME_REQUEST, 6);
                        if (error_code != 6) perror("TIME_REQUEST");
                        datum_pts->nbytes = 0;
                        break;
                }
        }

        /*
        ** Print out an error message if we could not find the right unit.
        */

        if (unit_index == -1) {

#ifdef DEBUG_DATUM_PTC
                if (debug)
                    printf("Error, could not poll unit %d\n",unit);
#endif

                msyslog(LOG_ERR, "Datum_PTS: Could not poll unit %d",unit);
                return;

        }

}


/*......................................................................*/
/*      datum_pts_control - not used                                    */
/*......................................................................*/

static void
datum_pts_control(
        int unit,
        struct refclockstat *in,
        struct refclockstat *out,
        struct peer *peer
        )
{

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Control Datum PTS\n");
#endif

}


/*......................................................................*/
/*      datum_pts_init - initializes things for all possible Datum      */
/*      time code generators that might be used. In practice, this is   */
/*      only called once at the beginning before anything else is       */
/*      called.                                                         */
/*......................................................................*/

static void
datum_pts_init(void)
{

        /*                                                                      */
        /*...... open up the log file if we are debugging ......................*/
        /*                                                                      */

        /*
        ** Open up the log file if we are debugging. For now, send data out to the
        ** screen (stdout).
        */

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Init Datum PTS\n");
#endif

        /*
        ** Initialize the time request command string. This is the only message
        ** that we ever have to send to the Datum PTS (although others are defined).
        */

        memcpy(TIME_REQUEST, "//k/mn",6);

        /*
        ** Initialize the number of units to 0 and set the dynamic array of units to
        ** NULL since there are no units defined yet.
        */

        datum_pts_unit = NULL;
        nunits = 0;

}


/*......................................................................*/
/*      datum_pts_buginfo - not used                                    */
/*......................................................................*/

static void
datum_pts_buginfo(
        int unit,
        register struct refclockbug *bug,
        register struct peer *peer
        )
{

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Buginfo Datum PTS\n");
#endif

}


/*......................................................................*/
/*      datum_pts_receive - receive the time buffer that was read in    */
/*      by the ntpd io handling routines. When 7 bytes have been        */
/*      received (it may take several tries before all 7 bytes are      */
/*      received), then the time code must be unpacked and sent to      */
/*      the ntpd clock_receive() routine which causes the systems       */
/*      clock to be updated (several layers down).                      */
/*......................................................................*/

static void
datum_pts_receive(
        struct recvbuf *rbufp
        )
{
        int i;
        l_fp tstmp;
        struct datum_pts_unit *datum_pts;
        char *dpt;
        int dpend;
        int tzoff;
        int timerr;
        double ftimerr, abserr;
#ifdef DEBUG_DATUM_PTC
        double dispersion;
#endif
        int goodtime;
      /*double doffset;*/

        /*
        ** Get the time code (maybe partial) message out of the rbufp buffer.
        */

        datum_pts = (struct datum_pts_unit *)rbufp->recv_srcclock;
        dpt = (char *)&rbufp->recv_space;
        dpend = rbufp->recv_length;

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Receive Datum PTS: %d bytes\n", dpend);
#endif

        /*                                                                      */
        /*...... save the ntp system time when the first byte is received ......*/
        /*                                                                      */

        /*
        ** Save the ntp system time when the first byte is received. Note that
        ** because it may take several calls to this routine before all seven
        ** bytes of our return message are finally received by the io handlers in
        ** ntpd, we really do want to use the time tag when the first byte is
        ** received to reduce the jitter.
        */

        if (datum_pts->nbytes == 0) {
                datum_pts->lastrec = rbufp->recv_time;
        }

        /*
        ** Increment our count to the number of bytes received so far. Return if we
        ** haven't gotten all seven bytes yet.
        */

        for (i=0; i<dpend; i++) {
                datum_pts->retbuf[datum_pts->nbytes+i] = dpt[i];
        }

        datum_pts->nbytes += dpend;

        if (datum_pts->nbytes != 7) {
                return;
        }

        /*
        ** Convert the seven bytes received in our time buffer to day, hour, minute,
        ** second, and msecond values. The usec value is not used for anything
        ** currently. It is just the fractional part of the time stored in units
        ** of microseconds.
        */

        datum_pts->day =        100*(datum_pts->retbuf[0] & 0x0f) +
                10*((datum_pts->retbuf[1] & 0xf0)>>4) +
                (datum_pts->retbuf[1] & 0x0f);

        datum_pts->hour =       10*((datum_pts->retbuf[2] & 0x30)>>4) +
                (datum_pts->retbuf[2] & 0x0f);

        datum_pts->minute =     10*((datum_pts->retbuf[3] & 0x70)>>4) +
                (datum_pts->retbuf[3] & 0x0f);

        datum_pts->second =     10*((datum_pts->retbuf[4] & 0x70)>>4) +
                (datum_pts->retbuf[4] & 0x0f);

        datum_pts->msec =       100*((datum_pts->retbuf[5] & 0xf0) >> 4) + 
                10*(datum_pts->retbuf[5] & 0x0f) +
                ((datum_pts->retbuf[6] & 0xf0)>>4);

        datum_pts->usec =       1000*datum_pts->msec;

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("day %d, hour %d, minute %d, second %d, msec %d\n",
                   datum_pts->day,
                   datum_pts->hour,
                   datum_pts->minute,
                   datum_pts->second,
                   datum_pts->msec);
#endif

        /*
        ** Get the GMT time zone offset. Note that GMT should be zero if the Datum
        ** reference time is using GMT as its time base. Otherwise we have to
        ** determine the offset if the Datum PTS is using time of day as its time
        ** base.
        */

        goodtime = 0;           /* We are not sure about the time and offset yet */

#ifdef GMT

        /*
        ** This is the case where the Datum PTS is using GMT so there is no time
        ** zone offset.
        */

        tzoff = 0;              /* set time zone offset to 0 */

#else

        /*
        ** This is the case where the Datum PTS is using regular time of day for its
        ** time so we must compute the time zone offset. The way we do it is kind of
        ** funny but it works. We loop through different time zones (0 to 24) and
        ** pick the one that gives the smallest error (+- one half hour). The time
        ** zone offset is stored in the datum_pts structure for future use. Normally,
        ** the clocktime() routine is only called once (unless the time zone offset
        ** changes due to daylight savings) since the goodtime flag is set when a
        ** good time is found (with a good offset). Note that even if the Datum
        ** PTS is using GMT, this mechanism will still work since it should come up
        ** with a value for tzoff = 0 (assuming that your system clock is within
        ** a half hour of the Datum time (even with time zone differences).
        */

        for (tzoff=0; tzoff<24; tzoff++) {
                if (clocktime( datum_pts->day,
                               datum_pts->hour,
                               datum_pts->minute,
                               datum_pts->second,
                               (tzoff + datum_pts->tzoff) % 24,
                               datum_pts->lastrec.l_ui,
                               &datum_pts->yearstart,
                               &datum_pts->lastref.l_ui) ) {

                        datum_pts->lastref.l_uf = 0;
                        error = datum_pts->lastref.l_ui - datum_pts->lastrec.l_ui;

#ifdef DEBUG_DATUM_PTC
                        printf("Time Zone (clocktime method) = %d, error = %d\n", tzoff, error);
#endif

                        if ((error < 1799) && (error > -1799)) {
                                tzoff = (tzoff + datum_pts->tzoff) % 24;
                                datum_pts->tzoff = tzoff;
                                goodtime = 1;

#ifdef DEBUG_DATUM_PTC
                                printf("Time Zone found (clocktime method) = %d\n",tzoff);
#endif

                                break;
                        }

                }
        }

#endif

        /*
        ** Make sure that we have a good time from the Datum PTS. Clocktime() also
        ** sets yearstart and lastref.l_ui. We will have to set astref.l_uf (i.e.,
        ** the fraction of a second) stuff later.
        */

        if (!goodtime) {

                if (!clocktime( datum_pts->day,
                                datum_pts->hour,
                                datum_pts->minute,
                                datum_pts->second,
                                tzoff,
                                datum_pts->lastrec.l_ui,
                                &datum_pts->yearstart,
                                &datum_pts->lastref.l_ui) ) {

#ifdef DEBUG_DATUM_PTC
                        if (debug)
                        {
                                printf("Error: bad clocktime\n");
                                printf("GMT %d, lastrec %d, yearstart %d, lastref %d\n",
                                       tzoff,
                                       datum_pts->lastrec.l_ui,
                                       datum_pts->yearstart,
                                       datum_pts->lastref.l_ui);
                        }
#endif

                        msyslog(LOG_ERR, "Datum_PTS: Bad clocktime");

                        return;

                }else{

#ifdef DEBUG_DATUM_PTC
                        if (debug)
                            printf("Good clocktime\n");
#endif

                }

        }

        /*
        ** We have datum_pts->lastref.l_ui set (which is the integer part of the
        ** time. Now set the microseconds field.
        */

        TVUTOTSF(datum_pts->usec, datum_pts->lastref.l_uf);

        /*
        ** Compute the time correction as the difference between the reference
        ** time (i.e., the Datum time) minus the receive time (system time).
        */

        tstmp = datum_pts->lastref;             /* tstmp is the datum ntp time */
        L_SUB(&tstmp, &datum_pts->lastrec);     /* tstmp is now the correction */
        datum_pts->coderecv++;          /* increment a counter */

#ifdef DEBUG_DATUM_PTC
        dispersion = DATUM_DISPERSION;  /* set the dispersion to 0 */
        ftimerr = dispersion;
        ftimerr /= (1024.0 * 64.0);
        if (debug)
            printf("dispersion = %d, %f\n", dispersion, ftimerr);
#endif

        /*
        ** Pass the new time to ntpd through the refclock_receive function. Note
        ** that we are not trying to make any corrections due to the time it takes
        ** for the Datum PTS to send the message back. I am (erroneously) assuming
        ** that the time for the Datum PTS to send the time back to us is negligable.
        ** I suspect that this time delay may be as much as 15 ms or so (but probably
        ** less). For our needs at JPL, this kind of error is ok so it is not
        ** necessary to use fudge factors in the ntp.conf file. Maybe later we will.
        */
      /*LFPTOD(&tstmp, doffset);*/
        datum_pts->lastref = datum_pts->lastrec;
        refclock_receive(datum_pts->peer);

        /*
        ** Compute sigma squared (not used currently). Maybe later, this could be
        ** used for the dispersion estimate. The problem is that ntpd does not link
        ** in the math library so sqrt() is not available. Anyway, this is useful
        ** for debugging. Maybe later I will just use absolute values for the time
        ** error to come up with my dispersion estimate. Anyway, for now my dispersion
        ** is set to 0.
        */

        timerr = tstmp.l_ui<<20;
        timerr |= (tstmp.l_uf>>12) & 0x000fffff;
        ftimerr = timerr;
        ftimerr /= 1024*1024;
        abserr = ftimerr;
        if (ftimerr < 0.0) abserr = -ftimerr;

        if (datum_pts->sigma2 == 0.0) {
                if (abserr < DATUM_MAX_ERROR) {
                        datum_pts->sigma2 = abserr*abserr;
                }else{
                        datum_pts->sigma2 = DATUM_MAX_ERROR2;
                }
        }else{
                if (abserr < DATUM_MAX_ERROR) {
                        datum_pts->sigma2 = 0.95*datum_pts->sigma2 + 0.05*abserr*abserr;
                }else{
                        datum_pts->sigma2 = 0.95*datum_pts->sigma2 + 0.05*DATUM_MAX_ERROR2;
                }
        }

#ifdef DEBUG_DATUM_PTC
        if (debug)
            printf("Time error = %f seconds\n", ftimerr);
#endif

#if defined(DEBUG_DATUM_PTC) || defined(LOG_TIME_ERRORS)
        if (debug)
            printf("PTS: day %d, hour %d, minute %d, second %d, msec %d, Time Error %f\n",
                   datum_pts->day,
                   datum_pts->hour,
                   datum_pts->minute,
                   datum_pts->second,
                   datum_pts->msec,
                   ftimerr);
#endif

}
#else
int refclock_datum_bs;
#endif /* REFCLOCK */