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/contrib/ntp/ntpd/refclock_datum.c

https://bitbucket.org/freebsd/freebsd-head/
C | 877 lines | 425 code | 168 blank | 284 comment | 51 complexity | 9e0de6bb2668e65794a9722f23533ea2 MD5 | raw file
  1/*
  2** refclock_datum - clock driver for the Datum Programmable Time Server
  3**
  4** Important note: This driver assumes that you have termios. If you have
  5** a system that does not have termios, you will have to modify this driver.
  6**
  7** Sorry, I have only tested this driver on SUN and HP platforms.
  8*/
  9
 10#ifdef HAVE_CONFIG_H
 11# include <config.h>
 12#endif
 13
 14#if defined(REFCLOCK) && defined(CLOCK_DATUM)
 15
 16/*
 17** Include Files
 18*/
 19
 20#include "ntpd.h"
 21#include "ntp_io.h"
 22#include "ntp_refclock.h"
 23#include "ntp_unixtime.h"
 24#include "ntp_stdlib.h"
 25
 26#include <stdio.h>
 27#include <ctype.h>
 28
 29#if defined(HAVE_BSD_TTYS)
 30#include <sgtty.h>
 31#endif /* HAVE_BSD_TTYS */
 32
 33#if defined(HAVE_SYSV_TTYS)
 34#include <termio.h>
 35#endif /* HAVE_SYSV_TTYS */
 36
 37#if defined(HAVE_TERMIOS)
 38#include <termios.h>
 39#endif
 40#if defined(STREAM)
 41#include <stropts.h>
 42#if defined(WWVBCLK)
 43#include <sys/clkdefs.h>
 44#endif /* WWVBCLK */
 45#endif /* STREAM */
 46
 47#include "ntp_stdlib.h"
 48
 49/*
 50** This driver supports the Datum Programmable Time System (PTS) clock.
 51** The clock works in very straight forward manner. When it receives a
 52** time code request (e.g., the ascii string "//k/mn"), it responds with
 53** a seven byte BCD time code. This clock only responds with a
 54** time code after it first receives the "//k/mn" message. It does not
 55** periodically send time codes back at some rate once it is started.
 56** the returned time code can be broken down into the following fields.
 57**
 58**            _______________________________
 59** Bit Index | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
 60**            ===============================
 61** byte 0:   | -   -   -   - |      H D      |
 62**            ===============================
 63** byte 1:   |      T D      |      U D      |
 64**            ===============================
 65** byte 2:   | -   - |  T H  |      U H      |
 66**            ===============================
 67** byte 3:   | - |    T M    |      U M      |
 68**            ===============================
 69** byte 4:   | - |    T S    |      U S      |
 70**            ===============================
 71** byte 5:   |      t S      |      h S      |
 72**            ===============================
 73** byte 6:   |      m S      | -   -   -   - |
 74**            ===============================
 75**
 76** In the table above:
 77**
 78**	"-" means don't care
 79**	"H D", "T D", and "U D" means Hundreds, Tens, and Units of Days
 80**	"T H", and "UH" means Tens and Units of Hours
 81**	"T M", and "U M" means Tens and Units of Minutes
 82**	"T S", and "U S" means Tens and Units of Seconds
 83**	"t S", "h S", and "m S" means tenths, hundredths, and thousandths
 84**				of seconds
 85**
 86** The Datum PTS communicates throught the RS232 port on your machine.
 87** Right now, it assumes that you have termios. This driver has been tested
 88** on SUN and HP workstations. The Datum PTS supports various IRIG and
 89** NASA input codes. This driver assumes that the name of the device is
 90** /dev/datum. You will need to make a soft link to your RS232 device or
 91** create a new driver to use this refclock.
 92*/
 93
 94/*
 95** Datum PTS defines
 96*/
 97
 98/*
 99** Note that if GMT is defined, then the Datum PTS must use Greenwich
100** time. Otherwise, this driver allows the Datum PTS to use the current
101** wall clock for its time. It determines the time zone offset by minimizing
102** the error after trying several time zone offsets. If the Datum PTS
103** time is Greenwich time and GMT is not defined, everything should still
104** work since the time zone will be found to be 0. What this really means
105** is that your system time (at least to start with) must be within the
106** correct time by less than +- 30 minutes. The default is for GMT to not
107** defined. If you really want to force GMT without the funny +- 30 minute
108** stuff then you must define (uncomment) GMT below.
109*/
110
111/*
112#define GMT
113#define DEBUG_DATUM_PTC
114#define LOG_TIME_ERRORS
115*/
116
117
118#define	PRECISION	(-10)		/* precision assumed 1/1024 ms */
119#define	REFID "DATM"			/* reference id */
120#define DATUM_DISPERSION 0		/* fixed dispersion = 0 ms */
121#define DATUM_MAX_ERROR 0.100		/* limits on sigma squared */
122#define DATUM_DEV	"/dev/datum"	/* device name */
123
124#define DATUM_MAX_ERROR2 (DATUM_MAX_ERROR*DATUM_MAX_ERROR)
125
126/*
127** The Datum PTS structure
128*/
129
130/*
131** I don't use a fixed array of MAXUNITS like everyone else just because
132** I don't like to program that way. Sorry if this bothers anyone. I assume
133** that you can use any id for your unit and I will search for it in a
134** dynamic array of units until I find it. I was worried that users might
135** enter a bad id in their configuration file (larger than MAXUNITS) and
136** besides, it is just cleaner not to have to assume that you have a fixed
137** number of anything in a program.
138*/
139
140struct datum_pts_unit {
141	struct peer *peer;		/* peer used by ntp */
142	struct refclockio io;		/* io structure used by ntp */
143	int PTS_fd;			/* file descriptor for PTS */
144	u_int unit;			/* id for unit */
145	u_long timestarted;		/* time started */
146	l_fp lastrec;			/* time tag for the receive time (system) */
147	l_fp lastref;			/* reference time (Datum time) */
148	u_long yearstart;		/* the year that this clock started */
149	int coderecv;			/* number of time codes received */
150	int day;			/* day */
151	int hour;			/* hour */
152	int minute;			/* minutes */
153	int second;			/* seconds */
154	int msec;			/* miliseconds */
155	int usec;			/* miliseconds */
156	u_char leap;			/* funny leap character code */
157	char retbuf[8];		/* returned time from the datum pts */
158	char nbytes;			/* number of bytes received from datum pts */ 
159	double sigma2;		/* average squared error (roughly) */
160	int tzoff;			/* time zone offest from GMT */
161};
162
163/*
164** PTS static constant variables for internal use
165*/
166
167static char TIME_REQUEST[6];	/* request message sent to datum for time */
168static int nunits;		/* number of active units */
169static struct datum_pts_unit
170**datum_pts_unit;	/* dynamic array of datum PTS structures */
171
172/*
173** Callback function prototypes that ntpd needs to know about.
174*/
175
176static	int	datum_pts_start		P((int, struct peer *));
177static	void	datum_pts_shutdown	P((int, struct peer *));
178static	void	datum_pts_poll		P((int, struct peer *));
179static	void	datum_pts_control	P((int, struct refclockstat *,
180					   struct refclockstat *, struct peer *));
181static	void	datum_pts_init		P((void));
182static	void	datum_pts_buginfo	P((int, struct refclockbug *, struct peer *));
183
184/*
185** This is the call back function structure that ntpd actually uses for
186** this refclock.
187*/
188
189struct	refclock refclock_datum = {
190	datum_pts_start,		/* start up a new Datum refclock */
191	datum_pts_shutdown,		/* shutdown a Datum refclock */
192	datum_pts_poll,		/* sends out the time request */
193	datum_pts_control,		/* not used */
194	datum_pts_init,		/* initialization (called first) */
195	datum_pts_buginfo,		/* not used */
196	NOFLAGS			/* we are not setting any special flags */
197};
198
199/*
200** The datum_pts_receive callback function is handled differently from the
201** rest. It is passed to the ntpd io data structure. Basically, every
202** 64 seconds, the datum_pts_poll() routine is called. It sends out the time
203** request message to the Datum Programmable Time System. Then, ntpd
204** waits on a select() call to receive data back. The datum_pts_receive()
205** function is called as data comes back. We expect a seven byte time
206** code to be returned but the datum_pts_receive() function may only get
207** a few bytes passed to it at a time. In other words, this routine may
208** get called by the io stuff in ntpd a few times before we get all seven
209** bytes. Once the last byte is received, we process it and then pass the
210** new time measurement to ntpd for updating the system time. For now,
211** there is no 3 state filtering done on the time measurements. The
212** jitter may be a little high but at least for its current use, it is not
213** a problem. We have tried to keep things as simple as possible. This
214** clock should not jitter more than 1 or 2 mseconds at the most once
215** things settle down. It is important to get the right drift calibrated
216** in the ntpd.drift file as well as getting the right tick set up right
217** using tickadj for SUNs. Tickadj is not used for the HP but you need to
218** remember to bring up the adjtime daemon because HP does not support
219** the adjtime() call.
220*/
221
222static	void	datum_pts_receive	P((struct recvbuf *));
223
224/*......................................................................*/
225/*	datum_pts_start - start up the datum PTS. This means open the	*/
226/*	RS232 device and set up the data structure for my unit.		*/
227/*......................................................................*/
228
229static int
230datum_pts_start(
231	int unit,
232	struct peer *peer
233	)
234{
235	struct datum_pts_unit **temp_datum_pts_unit;
236	struct datum_pts_unit *datum_pts;
237	int fd;
238#ifdef HAVE_TERMIOS
239	struct termios arg;
240#endif
241
242#ifdef DEBUG_DATUM_PTC
243	if (debug)
244	    printf("Starting Datum PTS unit %d\n", unit);
245#endif
246
247	/*
248	** Open the Datum PTS device
249	*/
250	fd = open(DATUM_DEV, O_RDWR);
251
252	if (fd < 0) {
253		msyslog(LOG_ERR, "Datum_PTS: open(\"%s\", O_RDWR) failed: %m", DATUM_DEV);
254		return 0;
255	}
256
257	/*
258	** Create the memory for the new unit
259	*/
260
261	temp_datum_pts_unit = (struct datum_pts_unit **)
262		malloc((nunits+1)*sizeof(struct datum_pts_unit *));
263	if (nunits > 0) memcpy(temp_datum_pts_unit, datum_pts_unit,
264			       nunits*sizeof(struct datum_pts_unit *));
265	free(datum_pts_unit);
266	datum_pts_unit = temp_datum_pts_unit;
267	datum_pts_unit[nunits] = (struct datum_pts_unit *)
268		malloc(sizeof(struct datum_pts_unit));
269	datum_pts = datum_pts_unit[nunits];
270
271	datum_pts->unit = unit;	/* set my unit id */
272	datum_pts->yearstart = 0;	/* initialize the yearstart to 0 */
273	datum_pts->sigma2 = 0.0;	/* initialize the sigma2 to 0 */
274
275	datum_pts->PTS_fd = fd;
276
277	fcntl(datum_pts->PTS_fd, F_SETFL, 0); /* clear the descriptor flags */
278
279#ifdef DEBUG_DATUM_PTC
280	if (debug)
281	    printf("Opening RS232 port with file descriptor %d\n",
282		   datum_pts->PTS_fd);
283#endif
284
285	/*
286	** Set up the RS232 terminal device information. Note that we assume that
287	** we have termios. This code has only been tested on SUNs and HPs. If your
288	** machine does not have termios this driver cannot be initialized. You can change this
289	** if you want by editing this source. Please give the changes back to the
290	** ntp folks so that it can become part of their regular distribution.
291	*/
292
293#ifdef HAVE_TERMIOS
294
295	arg.c_iflag = IGNBRK;
296	arg.c_oflag = 0;
297	arg.c_cflag = B9600 | CS8 | CREAD | PARENB | CLOCAL;
298	arg.c_lflag = 0;
299	arg.c_cc[VMIN] = 0;		/* start timeout timer right away (not used) */
300	arg.c_cc[VTIME] = 30;		/* 3 second timout on reads (not used) */
301
302	tcsetattr(datum_pts->PTS_fd, TCSANOW, &arg);
303
304#else
305
306	msyslog(LOG_ERR, "Datum_PTS: Termios not supported in this driver");
307	(void)close(datum_pts->PTS_fd);
308
309	peer->precision = PRECISION;
310	pp->clockdesc = DESCRIPTION;
311	memcpy((char *)&pp->refid, REFID, 4);
312
313	return 0;
314
315#endif
316
317	/*
318	** Initialize the ntpd IO structure
319	*/
320
321	datum_pts->peer = peer;
322	datum_pts->io.clock_recv = datum_pts_receive;
323	datum_pts->io.srcclock = (caddr_t)datum_pts;
324	datum_pts->io.datalen = 0;
325	datum_pts->io.fd = datum_pts->PTS_fd;
326
327	if (!io_addclock(&(datum_pts->io))) {
328
329#ifdef DEBUG_DATUM_PTC
330		if (debug)
331		    printf("Problem adding clock\n");
332#endif
333
334		msyslog(LOG_ERR, "Datum_PTS: Problem adding clock");
335		(void)close(datum_pts->PTS_fd);
336
337		return 0;
338	}
339
340	/*
341	** Now add one to the number of units and return a successful code
342	*/
343
344	nunits++;
345	return 1;
346
347}
348
349
350/*......................................................................*/
351/*	datum_pts_shutdown - this routine shuts doen the device and	*/
352/*	removes the memory for the unit.				*/
353/*......................................................................*/
354
355static void
356datum_pts_shutdown(
357	int unit,
358	struct peer *peer
359	)
360{
361	int i,j;
362	struct datum_pts_unit **temp_datum_pts_unit;
363
364#ifdef DEBUG_DATUM_PTC
365	if (debug)
366	    printf("Shutdown Datum PTS\n");
367#endif
368
369	msyslog(LOG_ERR, "Datum_PTS: Shutdown Datum PTS");
370
371	/*
372	** First we have to find the right unit (i.e., the one with the same id).
373	** We do this by looping through the dynamic array of units intil we find
374	** it. Note, that I don't simply use an array with a maximimum number of
375	** Datum PTS units. Everything is completely dynamic.
376	*/
377
378	for (i=0; i<nunits; i++) {
379		if (datum_pts_unit[i]->unit == unit) {
380
381			/*
382			** We found the unit so close the file descriptor and free up the memory used
383			** by the structure.
384			*/
385
386			io_closeclock(&datum_pts_unit[i]->io);
387			close(datum_pts_unit[i]->PTS_fd);
388			free(datum_pts_unit[i]);
389
390			/*
391			** Now clean up the datum_pts_unit dynamic array so that there are no holes.
392			** This may mean moving pointers around, etc., to keep things compact.
393			*/
394
395			if (nunits > 1) {
396
397				temp_datum_pts_unit = (struct datum_pts_unit **)
398					malloc((nunits-1)*sizeof(struct datum_pts_unit *));
399				if (i!= 0) memcpy(temp_datum_pts_unit, datum_pts_unit,
400						  i*sizeof(struct datum_pts_unit *));
401
402				for (j=i+1; j<nunits; j++) {
403					temp_datum_pts_unit[j-1] = datum_pts_unit[j];
404				}
405
406				free(datum_pts_unit);
407				datum_pts_unit = temp_datum_pts_unit;
408
409			}else{
410
411				free(datum_pts_unit);
412				datum_pts_unit = NULL;
413
414			}
415
416			return;
417
418		}
419	}
420
421#ifdef DEBUG_DATUM_PTC
422	if (debug)
423	    printf("Error, could not shut down unit %d\n",unit);
424#endif
425
426	msyslog(LOG_ERR, "Datum_PTS: Could not shut down Datum PTS unit %d",unit);
427
428}
429
430/*......................................................................*/
431/*	datum_pts_poll - this routine sends out the time request to the */
432/*	Datum PTS device. The time will be passed back in the 		*/
433/*	datum_pts_receive() routine.					*/
434/*......................................................................*/
435
436static void
437datum_pts_poll(
438	int unit,
439	struct peer *peer
440	)
441{
442	int i;
443	int unit_index;
444	int error_code;
445	struct datum_pts_unit *datum_pts;
446
447#ifdef DEBUG_DATUM_PTC
448	if (debug)
449	    printf("Poll Datum PTS\n");
450#endif
451
452	/*
453	** Find the right unit and send out a time request once it is found.
454	*/
455
456	unit_index = -1;
457	for (i=0; i<nunits; i++) {
458		if (datum_pts_unit[i]->unit == unit) {
459			unit_index = i;
460			datum_pts = datum_pts_unit[i];
461			error_code = write(datum_pts->PTS_fd, TIME_REQUEST, 6);
462			if (error_code != 6) perror("TIME_REQUEST");
463			datum_pts->nbytes = 0;
464			break;
465		}
466	}
467
468	/*
469	** Print out an error message if we could not find the right unit.
470	*/
471
472	if (unit_index == -1) {
473
474#ifdef DEBUG_DATUM_PTC
475		if (debug)
476		    printf("Error, could not poll unit %d\n",unit);
477#endif
478
479		msyslog(LOG_ERR, "Datum_PTS: Could not poll unit %d",unit);
480		return;
481
482	}
483
484}
485
486
487/*......................................................................*/
488/*	datum_pts_control - not used					*/
489/*......................................................................*/
490
491static void
492datum_pts_control(
493	int unit,
494	struct refclockstat *in,
495	struct refclockstat *out,
496	struct peer *peer
497	)
498{
499
500#ifdef DEBUG_DATUM_PTC
501	if (debug)
502	    printf("Control Datum PTS\n");
503#endif
504
505}
506
507
508/*......................................................................*/
509/*	datum_pts_init - initializes things for all possible Datum	*/
510/*	time code generators that might be used. In practice, this is	*/
511/*	only called once at the beginning before anything else is	*/
512/*	called.								*/
513/*......................................................................*/
514
515static void
516datum_pts_init(void)
517{
518
519	/*									*/
520	/*...... open up the log file if we are debugging ......................*/
521	/*									*/
522
523	/*
524	** Open up the log file if we are debugging. For now, send data out to the
525	** screen (stdout).
526	*/
527
528#ifdef DEBUG_DATUM_PTC
529	if (debug)
530	    printf("Init Datum PTS\n");
531#endif
532
533	/*
534	** Initialize the time request command string. This is the only message
535	** that we ever have to send to the Datum PTS (although others are defined).
536	*/
537
538	memcpy(TIME_REQUEST, "//k/mn",6);
539
540	/*
541	** Initialize the number of units to 0 and set the dynamic array of units to
542	** NULL since there are no units defined yet.
543	*/
544
545	datum_pts_unit = NULL;
546	nunits = 0;
547
548}
549
550
551/*......................................................................*/
552/*	datum_pts_buginfo - not used					*/
553/*......................................................................*/
554
555static void
556datum_pts_buginfo(
557	int unit,
558	register struct refclockbug *bug,
559	register struct peer *peer
560	)
561{
562
563#ifdef DEBUG_DATUM_PTC
564	if (debug)
565	    printf("Buginfo Datum PTS\n");
566#endif
567
568}
569
570
571/*......................................................................*/
572/*	datum_pts_receive - receive the time buffer that was read in	*/
573/*	by the ntpd io handling routines. When 7 bytes have been	*/
574/*	received (it may take several tries before all 7 bytes are	*/
575/*	received), then the time code must be unpacked and sent to	*/
576/*	the ntpd clock_receive() routine which causes the systems	*/
577/*	clock to be updated (several layers down).			*/
578/*......................................................................*/
579
580static void
581datum_pts_receive(
582	struct recvbuf *rbufp
583	)
584{
585	int i;
586	l_fp tstmp;
587	struct datum_pts_unit *datum_pts;
588	char *dpt;
589	int dpend;
590	int tzoff;
591	int timerr;
592	double ftimerr, abserr;
593#ifdef DEBUG_DATUM_PTC
594	double dispersion;
595#endif
596	int goodtime;
597      /*double doffset;*/
598
599	/*
600	** Get the time code (maybe partial) message out of the rbufp buffer.
601	*/
602
603	datum_pts = (struct datum_pts_unit *)rbufp->recv_srcclock;
604	dpt = (char *)&rbufp->recv_space;
605	dpend = rbufp->recv_length;
606
607#ifdef DEBUG_DATUM_PTC
608	if (debug)
609	    printf("Receive Datum PTS: %d bytes\n", dpend);
610#endif
611
612	/*									*/
613	/*...... save the ntp system time when the first byte is received ......*/
614	/*									*/
615
616	/*
617	** Save the ntp system time when the first byte is received. Note that
618	** because it may take several calls to this routine before all seven
619	** bytes of our return message are finally received by the io handlers in
620	** ntpd, we really do want to use the time tag when the first byte is
621	** received to reduce the jitter.
622	*/
623
624	if (datum_pts->nbytes == 0) {
625		datum_pts->lastrec = rbufp->recv_time;
626	}
627
628	/*
629	** Increment our count to the number of bytes received so far. Return if we
630	** haven't gotten all seven bytes yet.
631	*/
632
633	for (i=0; i<dpend; i++) {
634		datum_pts->retbuf[datum_pts->nbytes+i] = dpt[i];
635	}
636
637	datum_pts->nbytes += dpend;
638
639	if (datum_pts->nbytes != 7) {
640		return;
641	}
642
643	/*
644	** Convert the seven bytes received in our time buffer to day, hour, minute,
645	** second, and msecond values. The usec value is not used for anything
646	** currently. It is just the fractional part of the time stored in units
647	** of microseconds.
648	*/
649
650	datum_pts->day =	100*(datum_pts->retbuf[0] & 0x0f) +
651		10*((datum_pts->retbuf[1] & 0xf0)>>4) +
652		(datum_pts->retbuf[1] & 0x0f);
653
654	datum_pts->hour =	10*((datum_pts->retbuf[2] & 0x30)>>4) +
655		(datum_pts->retbuf[2] & 0x0f);
656
657	datum_pts->minute =	10*((datum_pts->retbuf[3] & 0x70)>>4) +
658		(datum_pts->retbuf[3] & 0x0f);
659
660	datum_pts->second =	10*((datum_pts->retbuf[4] & 0x70)>>4) +
661		(datum_pts->retbuf[4] & 0x0f);
662
663	datum_pts->msec =	100*((datum_pts->retbuf[5] & 0xf0) >> 4) + 
664		10*(datum_pts->retbuf[5] & 0x0f) +
665		((datum_pts->retbuf[6] & 0xf0)>>4);
666
667	datum_pts->usec =	1000*datum_pts->msec;
668
669#ifdef DEBUG_DATUM_PTC
670	if (debug)
671	    printf("day %d, hour %d, minute %d, second %d, msec %d\n",
672		   datum_pts->day,
673		   datum_pts->hour,
674		   datum_pts->minute,
675		   datum_pts->second,
676		   datum_pts->msec);
677#endif
678
679	/*
680	** Get the GMT time zone offset. Note that GMT should be zero if the Datum
681	** reference time is using GMT as its time base. Otherwise we have to
682	** determine the offset if the Datum PTS is using time of day as its time
683	** base.
684	*/
685
686	goodtime = 0;		/* We are not sure about the time and offset yet */
687
688#ifdef GMT
689
690	/*
691	** This is the case where the Datum PTS is using GMT so there is no time
692	** zone offset.
693	*/
694
695	tzoff = 0;		/* set time zone offset to 0 */
696
697#else
698
699	/*
700	** This is the case where the Datum PTS is using regular time of day for its
701	** time so we must compute the time zone offset. The way we do it is kind of
702	** funny but it works. We loop through different time zones (0 to 24) and
703	** pick the one that gives the smallest error (+- one half hour). The time
704	** zone offset is stored in the datum_pts structure for future use. Normally,
705	** the clocktime() routine is only called once (unless the time zone offset
706	** changes due to daylight savings) since the goodtime flag is set when a
707	** good time is found (with a good offset). Note that even if the Datum
708	** PTS is using GMT, this mechanism will still work since it should come up
709	** with a value for tzoff = 0 (assuming that your system clock is within
710	** a half hour of the Datum time (even with time zone differences).
711	*/
712
713	for (tzoff=0; tzoff<24; tzoff++) {
714		if (clocktime( datum_pts->day,
715			       datum_pts->hour,
716			       datum_pts->minute,
717			       datum_pts->second,
718			       (tzoff + datum_pts->tzoff) % 24,
719			       datum_pts->lastrec.l_ui,
720			       &datum_pts->yearstart,
721			       &datum_pts->lastref.l_ui) ) {
722
723			datum_pts->lastref.l_uf = 0;
724			error = datum_pts->lastref.l_ui - datum_pts->lastrec.l_ui;
725
726#ifdef DEBUG_DATUM_PTC
727			printf("Time Zone (clocktime method) = %d, error = %d\n", tzoff, error);
728#endif
729
730			if ((error < 1799) && (error > -1799)) {
731				tzoff = (tzoff + datum_pts->tzoff) % 24;
732				datum_pts->tzoff = tzoff;
733				goodtime = 1;
734
735#ifdef DEBUG_DATUM_PTC
736				printf("Time Zone found (clocktime method) = %d\n",tzoff);
737#endif
738
739				break;
740			}
741
742		}
743	}
744
745#endif
746
747	/*
748	** Make sure that we have a good time from the Datum PTS. Clocktime() also
749	** sets yearstart and lastref.l_ui. We will have to set astref.l_uf (i.e.,
750	** the fraction of a second) stuff later.
751	*/
752
753	if (!goodtime) {
754
755		if (!clocktime( datum_pts->day,
756				datum_pts->hour,
757				datum_pts->minute,
758				datum_pts->second,
759				tzoff,
760				datum_pts->lastrec.l_ui,
761				&datum_pts->yearstart,
762				&datum_pts->lastref.l_ui) ) {
763
764#ifdef DEBUG_DATUM_PTC
765			if (debug)
766			{
767				printf("Error: bad clocktime\n");
768				printf("GMT %d, lastrec %d, yearstart %d, lastref %d\n",
769				       tzoff,
770				       datum_pts->lastrec.l_ui,
771				       datum_pts->yearstart,
772				       datum_pts->lastref.l_ui);
773			}
774#endif
775
776			msyslog(LOG_ERR, "Datum_PTS: Bad clocktime");
777
778			return;
779
780		}else{
781
782#ifdef DEBUG_DATUM_PTC
783			if (debug)
784			    printf("Good clocktime\n");
785#endif
786
787		}
788
789	}
790
791	/*
792	** We have datum_pts->lastref.l_ui set (which is the integer part of the
793	** time. Now set the microseconds field.
794	*/
795
796	TVUTOTSF(datum_pts->usec, datum_pts->lastref.l_uf);
797
798	/*
799	** Compute the time correction as the difference between the reference
800	** time (i.e., the Datum time) minus the receive time (system time).
801	*/
802
803	tstmp = datum_pts->lastref;		/* tstmp is the datum ntp time */
804	L_SUB(&tstmp, &datum_pts->lastrec);	/* tstmp is now the correction */
805	datum_pts->coderecv++;		/* increment a counter */
806
807#ifdef DEBUG_DATUM_PTC
808	dispersion = DATUM_DISPERSION;	/* set the dispersion to 0 */
809	ftimerr = dispersion;
810	ftimerr /= (1024.0 * 64.0);
811	if (debug)
812	    printf("dispersion = %d, %f\n", dispersion, ftimerr);
813#endif
814
815	/*
816	** Pass the new time to ntpd through the refclock_receive function. Note
817	** that we are not trying to make any corrections due to the time it takes
818	** for the Datum PTS to send the message back. I am (erroneously) assuming
819	** that the time for the Datum PTS to send the time back to us is negligable.
820	** I suspect that this time delay may be as much as 15 ms or so (but probably
821	** less). For our needs at JPL, this kind of error is ok so it is not
822	** necessary to use fudge factors in the ntp.conf file. Maybe later we will.
823	*/
824      /*LFPTOD(&tstmp, doffset);*/
825	datum_pts->lastref = datum_pts->lastrec;
826	refclock_receive(datum_pts->peer);
827
828	/*
829	** Compute sigma squared (not used currently). Maybe later, this could be
830	** used for the dispersion estimate. The problem is that ntpd does not link
831	** in the math library so sqrt() is not available. Anyway, this is useful
832	** for debugging. Maybe later I will just use absolute values for the time
833	** error to come up with my dispersion estimate. Anyway, for now my dispersion
834	** is set to 0.
835	*/
836
837	timerr = tstmp.l_ui<<20;
838	timerr |= (tstmp.l_uf>>12) & 0x000fffff;
839	ftimerr = timerr;
840	ftimerr /= 1024*1024;
841	abserr = ftimerr;
842	if (ftimerr < 0.0) abserr = -ftimerr;
843
844	if (datum_pts->sigma2 == 0.0) {
845		if (abserr < DATUM_MAX_ERROR) {
846			datum_pts->sigma2 = abserr*abserr;
847		}else{
848			datum_pts->sigma2 = DATUM_MAX_ERROR2;
849		}
850	}else{
851		if (abserr < DATUM_MAX_ERROR) {
852			datum_pts->sigma2 = 0.95*datum_pts->sigma2 + 0.05*abserr*abserr;
853		}else{
854			datum_pts->sigma2 = 0.95*datum_pts->sigma2 + 0.05*DATUM_MAX_ERROR2;
855		}
856	}
857
858#ifdef DEBUG_DATUM_PTC
859	if (debug)
860	    printf("Time error = %f seconds\n", ftimerr);
861#endif
862
863#if defined(DEBUG_DATUM_PTC) || defined(LOG_TIME_ERRORS)
864	if (debug)
865	    printf("PTS: day %d, hour %d, minute %d, second %d, msec %d, Time Error %f\n",
866		   datum_pts->day,
867		   datum_pts->hour,
868		   datum_pts->minute,
869		   datum_pts->second,
870		   datum_pts->msec,
871		   ftimerr);
872#endif
873
874}
875#else
876int refclock_datum_bs;
877#endif /* REFCLOCK */