xref: /freebsd/contrib/ntp/ntpd/refclock_arc.c (revision fcb560670601b2a4d87bb31d7531c8dcc37ee71b)
1 /*
2  * refclock_arc - clock driver for ARCRON MSF/DCF/WWVB receivers
3  */
4 
5 #ifdef HAVE_CONFIG_H
6 #include <config.h>
7 #endif
8 
9 #if defined(REFCLOCK) && defined(CLOCK_ARCRON_MSF)
10 
11 static const char arc_version[] = { "V1.3 2003/02/21" };
12 
13 /* define PRE_NTP420 for compatibility to previous versions of NTP (at least
14    to 4.1.0 */
15 #undef PRE_NTP420
16 
17 #ifndef ARCRON_NOT_KEEN
18 #define ARCRON_KEEN 1 /* Be keen, and trusting of the clock, if defined. */
19 #endif
20 
21 #ifndef ARCRON_NOT_MULTIPLE_SAMPLES
22 #define ARCRON_MULTIPLE_SAMPLES 1 /* Use all timestamp bytes as samples. */
23 #endif
24 
25 #ifndef ARCRON_NOT_LEAPSECOND_KEEN
26 #ifndef ARCRON_LEAPSECOND_KEEN
27 #undef ARCRON_LEAPSECOND_KEEN /* Respond quickly to leap seconds: doesn't work yet. */
28 #endif
29 #endif
30 
31 /*
32 Code by Derek Mulcahy, <derek@toybox.demon.co.uk>, 1997.
33 Modifications by Damon Hart-Davis, <d@hd.org>, 1997.
34 Modifications by Paul Alfille, <palfille@partners.org>, 2003.
35 Modifications by Christopher Price, <cprice@cs-home.com>, 2003.
36 Modifications by Nigel Roles <nigel@9fs.org>, 2003.
37 
38 
39 THIS CODE IS SUPPLIED AS IS, WITH NO WARRANTY OF ANY KIND.  USE AT
40 YOUR OWN RISK.
41 
42 Orginally developed and used with ntp3-5.85 by Derek Mulcahy.
43 
44 Built against ntp3-5.90 on Solaris 2.5 using gcc 2.7.2.
45 
46 This code may be freely copied and used and incorporated in other
47 systems providing the disclaimer and notice of authorship are
48 reproduced.
49 
50 -------------------------------------------------------------------------------
51 
52 Nigel's notes:
53 
54 1) Called tcgetattr() before modifying, so that fields correctly initialised
55    for all operating systems
56 
57 2) Altered parsing of timestamp line so that it copes with fields which are
58    not always ASCII digits (e.g. status field when battery low)
59 
60 -------------------------------------------------------------------------------
61 
62 Christopher's notes:
63 
64 MAJOR CHANGES SINCE V1.2
65 ========================
66  1) Applied patch by Andrey Bray <abuse@madhouse.demon.co.uk>
67     2001-02-17 comp.protocols.time.ntp
68 
69  2) Added WWVB support via clock mode command, localtime/UTC time configured
70     via flag1=(0=UTC, 1=localtime)
71 
72  3) Added ignore resync request via flag2=(0=resync, 1=ignore resync)
73 
74  4) Added simplified conversion from localtime to UTC with dst/bst translation
75 
76  5) Added average signal quality poll
77 
78  6) Fixed a badformat error when no code is available due to stripping
79     \n & \r's
80 
81  7) Fixed a badformat error when clearing lencode & memset a_lastcode in poll
82     routine
83 
84  8) Lots of code cleanup, including standardized DEBUG macros and removal
85     of unused code
86 
87 -------------------------------------------------------------------------------
88 
89 Author's original note:
90 
91 I enclose my ntp driver for the Galleon Systems Arc MSF receiver.
92 
93 It works (after a fashion) on both Solaris-1 and Solaris-2.
94 
95 I am currently using ntp3-5.85.  I have been running the code for
96 about 7 months without any problems.  Even coped with the change to BST!
97 
98 I had to do some funky things to read from the clock because it uses the
99 power from the receive lines to drive the transmit lines.  This makes the
100 code look a bit stupid but it works.  I also had to put in some delays to
101 allow for the turnaround time from receive to transmit.  These delays
102 are between characters when requesting a time stamp so that shouldn't affect
103 the results too drastically.
104 
105 ...
106 
107 The bottom line is that it works but could easily be improved.  You are
108 free to do what you will with the code.  I haven't been able to determine
109 how good the clock is.  I think that this requires a known good clock
110 to compare it against.
111 
112 -------------------------------------------------------------------------------
113 
114 Damon's notes for adjustments:
115 
116 MAJOR CHANGES SINCE V1.0
117 ========================
118  1) Removal of pollcnt variable that made the clock go permanently
119     off-line once two time polls failed to gain responses.
120 
121  2) Avoiding (at least on Solaris-2) terminal becoming the controlling
122     terminal of the process when we do a low-level open().
123 
124  3) Additional logic (conditional on ARCRON_LEAPSECOND_KEEN being
125     defined) to try to resync quickly after a potential leap-second
126     insertion or deletion.
127 
128  4) Code significantly slimmer at run-time than V1.0.
129 
130 
131 GENERAL
132 =======
133 
134  1) The C preprocessor symbol to have the clock built has been changed
135     from ARC to ARCRON_MSF to CLOCK_ARCRON_MSF to minimise the
136     possiblity of clashes with other symbols in the future.
137 
138  2) PRECISION should be -4/-5 (63ms/31ms) for the following reasons:
139 
140      a) The ARC documentation claims the internal clock is (only)
141         accurate to about 20ms relative to Rugby (plus there must be
142         noticable drift and delay in the ms range due to transmission
143         delays and changing atmospheric effects).  This clock is not
144         designed for ms accuracy as NTP has spoilt us all to expect.
145 
146      b) The clock oscillator looks like a simple uncompensated quartz
147         crystal of the sort used in digital watches (ie 32768Hz) which
148         can have large temperature coefficients and drifts; it is not
149         clear if this oscillator is properly disciplined to the MSF
150         transmission, but as the default is to resync only once per
151         *day*, we can imagine that it is not, and is free-running.  We
152         can minimise drift by resyncing more often (at the cost of
153         reduced battery life), but drift/wander may still be
154         significant.
155 
156      c) Note that the bit time of 3.3ms adds to the potential error in
157         the the clock timestamp, since the bit clock of the serial link
158         may effectively be free-running with respect to the host clock
159         and the MSF clock.  Actually, the error is probably 1/16th of
160         the above, since the input data is probably sampled at at least
161         16x the bit rate.
162 
163     By keeping the clock marked as not very precise, it will have a
164     fairly large dispersion, and thus will tend to be used as a
165     `backup' time source and sanity checker, which this clock is
166     probably ideal for.  For an isolated network without other time
167     sources, this clock can probably be expected to provide *much*
168     better than 1s accuracy, which will be fine.
169 
170     By default, PRECISION is set to -4, but experience, especially at a
171     particular geographic location with a particular clock, may allow
172     this to be altered to -5.  (Note that skews of +/- 10ms are to be
173     expected from the clock from time-to-time.)  This improvement of
174     reported precision can be instigated by setting flag3 to 1, though
175     the PRECISION will revert to the normal value while the clock
176     signal quality is unknown whatever the flag3 setting.
177 
178     IN ANY CASE, BE SURE TO SET AN APPROPRIATE FUDGE FACTOR TO REMOVE
179     ANY RESIDUAL SKEW, eg:
180 
181         server 127.127.27.0 # ARCRON MSF radio clock unit 0.
182         # Fudge timestamps by about 20ms.
183         fudge 127.127.27.0 time1 0.020
184 
185     You will need to observe your system's behaviour, assuming you have
186     some other NTP source to compare it with, to work out what the
187     fudge factor should be.  For my Sun SS1 running SunOS 4.1.3_U1 with
188     my MSF clock with my distance from the MSF transmitter, +20ms
189     seemed about right, after some observation.
190 
191  3) REFID has been made "MSFa" to reflect the MSF time source and the
192     ARCRON receiver.
193 
194  4) DEFAULT_RESYNC_TIME is the time in seconds (by default) before
195     forcing a resync since the last attempt.  This is picked to give a
196     little less than an hour between resyncs and to try to avoid
197     clashing with any regular event at a regular time-past-the-hour
198     which might cause systematic errors.
199 
200     The INITIAL_RESYNC_DELAY is to avoid bothering the clock and
201     running down its batteries unnecesarily if ntpd is going to crash
202     or be killed or reconfigured quickly.  If ARCRON_KEEN is defined
203     then this period is long enough for (with normal polling rates)
204     enough time samples to have been taken to allow ntpd to sync to
205     the clock before the interruption for the clock to resync to MSF.
206     This avoids ntpd syncing to another peer first and then
207     almost immediately hopping to the MSF clock.
208 
209     The RETRY_RESYNC_TIME is used before rescheduling a resync after a
210     resync failed to reveal a statisfatory signal quality (too low or
211     unknown).
212 
213  5) The clock seems quite jittery, so I have increased the
214     median-filter size from the typical (previous) value of 3.  I
215     discard up to half the results in the filter.  It looks like maybe
216     1 sample in 10 or so (maybe less) is a spike, so allow the median
217     filter to discard at least 10% of its entries or 1 entry, whichever
218     is greater.
219 
220  6) Sleeping *before* each character sent to the unit to allow required
221     inter-character time but without introducting jitter and delay in
222     handling the response if possible.
223 
224  7) If the flag ARCRON_KEEN is defined, take time samples whenever
225     possible, even while resyncing, etc.  We rely, in this case, on the
226     clock always giving us a reasonable time or else telling us in the
227     status byte at the end of the timestamp that it failed to sync to
228     MSF---thus we should never end up syncing to completely the wrong
229     time.
230 
231  8) If the flag ARCRON_OWN_FILTER is defined, use own versions of
232     refclock median-filter routines to get round small bug in 3-5.90
233     code which does not return the median offset. XXX Removed this
234     bit due NTP Version 4 upgrade - dlm.
235 
236  9) We would appear to have a year-2000 problem with this clock since
237     it returns only the two least-significant digits of the year.  But
238     ntpd ignores the year and uses the local-system year instead, so
239     this is in fact not a problem.  Nevertheless, we attempt to do a
240     sensible thing with the dates, wrapping them into a 100-year
241     window.
242 
243  10)Logs stats information that can be used by Derek's Tcl/Tk utility
244     to show the status of the clock.
245 
246  11)The clock documentation insists that the number of bits per
247     character to be sent to the clock, and sent by it, is 11, including
248     one start bit and two stop bits.  The data format is either 7+even
249     or 8+none.
250 
251 
252 TO-DO LIST
253 ==========
254 
255   * Eliminate use of scanf(), and maybe sprintf().
256 
257   * Allow user setting of resync interval to trade battery life for
258     accuracy; maybe could be done via fudge factor or unit number.
259 
260   * Possibly note the time since the last resync of the MSF clock to
261     MSF as the age of the last reference timestamp, ie trust the
262     clock's oscillator not very much...
263 
264   * Add very slow auto-adjustment up to a value of +/- time2 to correct
265     for long-term errors in the clock value (time2 defaults to 0 so the
266     correction would be disabled by default).
267 
268   * Consider trying to use the tty_clk/ppsclock support.
269 
270   * Possibly use average or maximum signal quality reported during
271     resync, rather than just the last one, which may be atypical.
272 
273 */
274 
275 
276 /* Notes for HKW Elektronik GmBH Radio clock driver */
277 /* Author Lyndon David, Sentinet Ltd, Feb 1997      */
278 /* These notes seem also to apply usefully to the ARCRON clock. */
279 
280 /* The HKW clock module is a radio receiver tuned into the Rugby */
281 /* MSF time signal tranmitted on 60 kHz. The clock module connects */
282 /* to the computer via a serial line and transmits the time encoded */
283 /* in 15 bytes at 300 baud 7 bits two stop bits even parity */
284 
285 /* Clock communications, from the datasheet */
286 /* All characters sent to the clock are echoed back to the controlling */
287 /* device. */
288 /* Transmit time/date information */
289 /* syntax ASCII o<cr> */
290 /* Character o may be replaced if neccesary by a character whose code */
291 /* contains the lowest four bits f(hex) eg */
292 /* syntax binary: xxxx1111 00001101 */
293 
294 /* DHD note:
295 You have to wait for character echo + 10ms before sending next character.
296 */
297 
298 /* The clock replies to this command with a sequence of 15 characters */
299 /* which contain the complete time and a final <cr> making 16 characters */
300 /* in total. */
301 /* The RC computer clock will not reply immediately to this command because */
302 /* the start bit edge of the first reply character marks the beginning of */
303 /* the second. So the RC Computer Clock will reply to this command at the */
304 /* start of the next second */
305 /* The characters have the following meaning */
306 /* 1. hours tens   */
307 /* 2. hours units  */
308 /* 3. minutes tens */
309 /* 4. minutes units */
310 /* 5. seconds tens  */
311 /* 6. seconds units */
312 /* 7. day of week 1-monday 7-sunday */
313 /* 8. day of month tens */
314 /* 9. day of month units */
315 /* 10. month tens */
316 /* 11. month units */
317 /* 12. year tens */
318 /* 13. year units */
319 /* 14. BST/UTC status */
320 /*      bit 7   parity */
321 /*      bit 6   always 0 */
322 /*      bit 5   always 1 */
323 /*      bit 4   always 1 */
324 /*      bit 3   always 0 */
325 /*      bit 2   =1 if UTC is in effect, complementary to the BST bit */
326 /*      bit 1   =1 if BST is in effect, according to the BST bit     */
327 /*      bit 0   BST/UTC change impending bit=1 in case of change impending */
328 /* 15. status */
329 /*      bit 7   parity */
330 /*      bit 6   always 0 */
331 /*      bit 5   always 1 */
332 /*      bit 4   always 1 */
333 /*      bit 3   =1 if low battery is detected */
334 /*      bit 2   =1 if the very last reception attempt failed and a valid */
335 /*              time information already exists (bit0=1) */
336 /*              =0 if the last reception attempt was successful */
337 /*      bit 1   =1 if at least one reception since 2:30 am was successful */
338 /*              =0 if no reception attempt since 2:30 am was successful */
339 /*      bit 0   =1 if the RC Computer Clock contains valid time information */
340 /*              This bit is zero after reset and one after the first */
341 /*              successful reception attempt */
342 
343 /* DHD note:
344 Also note g<cr> command which confirms that a resync is in progress, and
345 if so what signal quality (0--5) is available.
346 Also note h<cr> command which starts a resync to MSF signal.
347 */
348 
349 
350 #include "ntpd.h"
351 #include "ntp_io.h"
352 #include "ntp_refclock.h"
353 #include "ntp_calendar.h"
354 #include "ntp_stdlib.h"
355 
356 #include <stdio.h>
357 #include <ctype.h>
358 
359 #if defined(HAVE_BSD_TTYS)
360 #include <sgtty.h>
361 #endif /* HAVE_BSD_TTYS */
362 
363 #if defined(HAVE_SYSV_TTYS)
364 #include <termio.h>
365 #endif /* HAVE_SYSV_TTYS */
366 
367 #if defined(HAVE_TERMIOS)
368 #include <termios.h>
369 #endif
370 
371 /*
372  * This driver supports the ARCRON MSF/DCF/WWVB Radio Controlled Clock
373  */
374 
375 /*
376  * Interface definitions
377  */
378 #define DEVICE          "/dev/arc%d"    /* Device name and unit. */
379 #define SPEED           B300            /* UART speed (300 baud) */
380 #define PRECISION       (-4)            /* Precision  (~63 ms). */
381 #define HIGHPRECISION   (-5)            /* If things are going well... */
382 #define REFID           "MSFa"          /* Reference ID. */
383 #define REFID_MSF       "MSF"           /* Reference ID. */
384 #define REFID_DCF77     "DCF"           /* Reference ID. */
385 #define REFID_WWVB      "WWVB"          /* Reference ID. */
386 #define DESCRIPTION     "ARCRON MSF/DCF/WWVB Receiver"
387 
388 #ifdef PRE_NTP420
389 #define MODE ttlmax
390 #else
391 #define MODE ttl
392 #endif
393 
394 #define LENARC          16              /* Format `o' timecode length. */
395 
396 #define BITSPERCHAR     11              /* Bits per character. */
397 #define BITTIME         0x0DA740E       /* Time for 1 bit at 300bps. */
398 #define CHARTIME10      0x8888888       /* Time for 10-bit char at 300bps. */
399 #define CHARTIME11      0x962FC96       /* Time for 11-bit char at 300bps. */
400 #define CHARTIME                        /* Time for char at 300bps. */ \
401 ( (BITSPERCHAR == 11) ? CHARTIME11 : ( (BITSPERCHAR == 10) ? CHARTIME10 : \
402 				       (BITSPERCHAR * BITTIME) ) )
403 
404      /* Allow for UART to accept char half-way through final stop bit. */
405 #define INITIALOFFSET (u_int32)(-BITTIME/2)
406 
407      /*
408     charoffsets[x] is the time after the start of the second that byte
409     x (with the first byte being byte 1) is received by the UART,
410     assuming that the initial edge of the start bit of the first byte
411     is on-time.  The values are represented as the fractional part of
412     an l_fp.
413 
414     We store enough values to have the offset of each byte including
415     the trailing \r, on the assumption that the bytes follow one
416     another without gaps.
417     */
418      static const u_int32 charoffsets[LENARC+1] = {
419 #if BITSPERCHAR == 11 /* Usual case. */
420 	     /* Offsets computed as accurately as possible... */
421 	     0,
422 	     INITIALOFFSET + 0x0962fc96, /*  1 chars,  11 bits */
423 	     INITIALOFFSET + 0x12c5f92c, /*  2 chars,  22 bits */
424 	     INITIALOFFSET + 0x1c28f5c3, /*  3 chars,  33 bits */
425 	     INITIALOFFSET + 0x258bf259, /*  4 chars,  44 bits */
426 	     INITIALOFFSET + 0x2eeeeeef, /*  5 chars,  55 bits */
427 	     INITIALOFFSET + 0x3851eb85, /*  6 chars,  66 bits */
428 	     INITIALOFFSET + 0x41b4e81b, /*  7 chars,  77 bits */
429 	     INITIALOFFSET + 0x4b17e4b1, /*  8 chars,  88 bits */
430 	     INITIALOFFSET + 0x547ae148, /*  9 chars,  99 bits */
431 	     INITIALOFFSET + 0x5dddddde, /* 10 chars, 110 bits */
432 	     INITIALOFFSET + 0x6740da74, /* 11 chars, 121 bits */
433 	     INITIALOFFSET + 0x70a3d70a, /* 12 chars, 132 bits */
434 	     INITIALOFFSET + 0x7a06d3a0, /* 13 chars, 143 bits */
435 	     INITIALOFFSET + 0x8369d037, /* 14 chars, 154 bits */
436 	     INITIALOFFSET + 0x8ccccccd, /* 15 chars, 165 bits */
437 	     INITIALOFFSET + 0x962fc963  /* 16 chars, 176 bits */
438 #else
439 	     /* Offsets computed with a small rounding error... */
440 	     0,
441 	     INITIALOFFSET +  1 * CHARTIME,
442 	     INITIALOFFSET +  2 * CHARTIME,
443 	     INITIALOFFSET +  3 * CHARTIME,
444 	     INITIALOFFSET +  4 * CHARTIME,
445 	     INITIALOFFSET +  5 * CHARTIME,
446 	     INITIALOFFSET +  6 * CHARTIME,
447 	     INITIALOFFSET +  7 * CHARTIME,
448 	     INITIALOFFSET +  8 * CHARTIME,
449 	     INITIALOFFSET +  9 * CHARTIME,
450 	     INITIALOFFSET + 10 * CHARTIME,
451 	     INITIALOFFSET + 11 * CHARTIME,
452 	     INITIALOFFSET + 12 * CHARTIME,
453 	     INITIALOFFSET + 13 * CHARTIME,
454 	     INITIALOFFSET + 14 * CHARTIME,
455 	     INITIALOFFSET + 15 * CHARTIME,
456 	     INITIALOFFSET + 16 * CHARTIME
457 #endif
458      };
459 
460 #define DEFAULT_RESYNC_TIME  (57*60)    /* Gap between resync attempts (s). */
461 #define RETRY_RESYNC_TIME    (27*60)    /* Gap to emergency resync attempt. */
462 #ifdef ARCRON_KEEN
463 #define INITIAL_RESYNC_DELAY 500        /* Delay before first resync. */
464 #else
465 #define INITIAL_RESYNC_DELAY 50         /* Delay before first resync. */
466 #endif
467 
468      static const int moff[12] =
469 { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
470 /* Flags for a raw open() of the clock serial device. */
471 #ifdef O_NOCTTY /* Good, we can avoid tty becoming controlling tty. */
472 #define OPEN_FLAGS (O_RDWR | O_NOCTTY)
473 #else           /* Oh well, it may not matter... */
474 #define OPEN_FLAGS (O_RDWR)
475 #endif
476 
477 
478 /* Length of queue of command bytes to be sent. */
479 #define CMDQUEUELEN 4                   /* Enough for two cmds + each \r. */
480 /* Queue tick time; interval in seconds between chars taken off queue. */
481 /* Must be >= 2 to allow o\r response to come back uninterrupted. */
482 #define QUEUETICK   2                   /* Allow o\r reply to finish. */
483 
484 /*
485  * ARC unit control structure
486  */
487 struct arcunit {
488 	l_fp lastrec;       /* Time tag for the receive time (system). */
489 	int status;         /* Clock status. */
490 
491 	int quality;        /* Quality of reception 0--5 for unit. */
492 	/* We may also use the values -1 or 6 internally. */
493 	u_long quality_stamp; /* Next time to reset quality average. */
494 
495 	u_long next_resync; /* Next resync time (s) compared to current_time. */
496 	int resyncing;      /* Resync in progress if true. */
497 
498 	/* In the outgoing queue, cmdqueue[0] is next to be sent. */
499 	char cmdqueue[CMDQUEUELEN+1]; /* Queue of outgoing commands + \0. */
500 
501 	u_long saved_flags; /* Saved fudge flags. */
502 };
503 
504 #ifdef ARCRON_LEAPSECOND_KEEN
505 /* The flag `possible_leap' is set non-zero when any MSF unit
506        thinks a leap-second may have happened.
507 
508        Set whenever we receive a valid time sample in the first hour of
509        the first day of the first/seventh months.
510 
511        Outside the special hour this value is unconditionally set
512        to zero by the receive routine.
513 
514        On finding itself in this timeslot, as long as the value is
515        non-negative, the receive routine sets it to a positive value to
516        indicate a resync to MSF should be performed.
517 
518        In the poll routine, if this value is positive and we are not
519        already resyncing (eg from a sync that started just before
520        midnight), start resyncing and set this value negative to
521        indicate that a leap-triggered resync has been started.  Having
522        set this negative prevents the receive routine setting it
523        positive and thus prevents multiple resyncs during the witching
524        hour.
525      */
526 static int possible_leap = 0;       /* No resync required by default. */
527 #endif
528 
529 #if 0
530 static void dummy_event_handler P((struct peer *));
531 static void   arc_event_handler P((struct peer *));
532 #endif /* 0 */
533 
534 #define QUALITY_UNKNOWN     -1 /* Indicates unknown clock quality. */
535 #define MIN_CLOCK_QUALITY    0 /* Min quality clock will return. */
536 #define MIN_CLOCK_QUALITY_OK 3 /* Min quality for OK reception. */
537 #define MAX_CLOCK_QUALITY    5 /* Max quality clock will return. */
538 
539 /*
540  * Function prototypes
541  */
542 static  int     arc_start       P((int, struct peer *));
543 static  void    arc_shutdown    P((int, struct peer *));
544 static  void    arc_receive     P((struct recvbuf *));
545 static  void    arc_poll        P((int, struct peer *));
546 
547 /*
548  * Transfer vector
549  */
550 struct  refclock refclock_arc = {
551 	arc_start,              /* start up driver */
552 	arc_shutdown,           /* shut down driver */
553 	arc_poll,               /* transmit poll message */
554 	noentry,                /* not used (old arc_control) */
555 	noentry,                /* initialize driver (not used) */
556 	noentry,                /* not used (old arc_buginfo) */
557 	NOFLAGS                 /* not used */
558 };
559 
560 /* Queue us up for the next tick. */
561 #define ENQUEUE(up) \
562 	do { \
563 	     peer->nextaction = current_time + QUEUETICK; \
564 	} while(0)
565 
566 /* Placeholder event handler---does nothing safely---soaks up loose tick. */
567 static void
568 dummy_event_handler(
569 	struct peer *peer
570 	)
571 {
572 #ifdef DEBUG
573 	if(debug) { printf("arc: dummy_event_handler() called.\n"); }
574 #endif
575 }
576 
577 /*
578 Normal event handler.
579 
580 Take first character off queue and send to clock if not a null.
581 
582 Shift characters down and put a null on the end.
583 
584 We assume that there is no parallelism so no race condition, but even
585 if there is nothing bad will happen except that we might send some bad
586 data to the clock once in a while.
587 */
588 static void
589 arc_event_handler(
590 	struct peer *peer
591 	)
592 {
593 	struct refclockproc *pp = peer->procptr;
594 	register struct arcunit *up = (struct arcunit *)pp->unitptr;
595 	int i;
596 	char c;
597 #ifdef DEBUG
598 	if(debug > 2) { printf("arc: arc_event_handler() called.\n"); }
599 #endif
600 
601 	c = up->cmdqueue[0];       /* Next char to be sent. */
602 	/* Shift down characters, shifting trailing \0 in at end. */
603 	for(i = 0; i < CMDQUEUELEN; ++i)
604 	{ up->cmdqueue[i] = up->cmdqueue[i+1]; }
605 
606 	/* Don't send '\0' characters. */
607 	if(c != '\0') {
608 		if(write(pp->io.fd, &c, 1) != 1) {
609 			msyslog(LOG_NOTICE, "ARCRON: write to fd %d failed", pp->io.fd);
610 		}
611 #ifdef DEBUG
612 		else if(debug) { printf("arc: sent `%2.2x', fd %d.\n", c, pp->io.fd); }
613 #endif
614 	}
615 
616 	ENQUEUE(up);
617 }
618 
619 /*
620  * arc_start - open the devices and initialize data for processing
621  */
622 static int
623 arc_start(
624 	int unit,
625 	struct peer *peer
626 	)
627 {
628 	register struct arcunit *up;
629 	struct refclockproc *pp;
630 	int fd;
631 	char device[20];
632 #ifdef HAVE_TERMIOS
633 	struct termios arg;
634 #endif
635 
636 	msyslog(LOG_NOTICE, "ARCRON: %s: opening unit %d", arc_version, unit);
637 #ifdef DEBUG
638 	if(debug) {
639 		printf("arc: %s: attempt to open unit %d.\n", arc_version, unit);
640 	}
641 #endif
642 
643 	/* Prevent a ridiculous device number causing overflow of device[]. */
644 	if((unit < 0) || (unit > 255)) { return(0); }
645 
646 	/*
647 	 * Open serial port. Use CLK line discipline, if available.
648 	 */
649 	(void)sprintf(device, DEVICE, unit);
650 	if (!(fd = refclock_open(device, SPEED, LDISC_CLK)))
651 		return(0);
652 #ifdef DEBUG
653 	if(debug) { printf("arc: unit %d using open().\n", unit); }
654 #endif
655 	fd = open(device, OPEN_FLAGS);
656 	if(fd < 0) {
657 #ifdef DEBUG
658 		if(debug) { printf("arc: failed [open()] to open %s.\n", device); }
659 #endif
660 		return(0);
661 	}
662 
663 	fcntl(fd, F_SETFL, 0); /* clear the descriptor flags */
664 #ifdef DEBUG
665 	if(debug)
666 	{ printf("arc: opened RS232 port with file descriptor %d.\n", fd); }
667 #endif
668 
669 #ifdef HAVE_TERMIOS
670 
671 	tcgetattr(fd, &arg);
672 
673 	arg.c_iflag = IGNBRK | ISTRIP;
674 	arg.c_oflag = 0;
675 	arg.c_cflag = B300 | CS8 | CREAD | CLOCAL | CSTOPB;
676 	arg.c_lflag = 0;
677 	arg.c_cc[VMIN] = 1;
678 	arg.c_cc[VTIME] = 0;
679 
680 	tcsetattr(fd, TCSANOW, &arg);
681 
682 #else
683 
684 	msyslog(LOG_ERR, "ARCRON: termios not supported in this driver");
685 	(void)close(fd);
686 
687 	return 0;
688 
689 #endif
690 
691 	up = (struct arcunit *) emalloc(sizeof(struct arcunit));
692 	if(!up) { (void) close(fd); return(0); }
693 	/* Set structure to all zeros... */
694 	memset((char *)up, 0, sizeof(struct arcunit));
695 	pp = peer->procptr;
696 	pp->io.clock_recv = arc_receive;
697 	pp->io.srcclock = (caddr_t)peer;
698 	pp->io.datalen = 0;
699 	pp->io.fd = fd;
700 	if(!io_addclock(&pp->io)) { (void) close(fd); free(up); return(0); }
701 	pp->unitptr = (caddr_t)up;
702 
703 	/*
704 	 * Initialize miscellaneous variables
705 	 */
706 	peer->precision = PRECISION;
707 	peer->stratum = 2;              /* Default to stratum 2 not 0. */
708 	pp->clockdesc = DESCRIPTION;
709 	if (peer->MODE > 3) {
710 		msyslog(LOG_NOTICE, "ARCRON: Invalid mode %d", peer->MODE);
711 		return 0;
712 	}
713 #ifdef DEBUG
714 	if(debug) { printf("arc: mode = %d.\n", peer->MODE); }
715 #endif
716 	switch (peer->MODE) {
717 	    case 1:
718 		memcpy((char *)&pp->refid, REFID_MSF, 4);
719 		break;
720 	    case 2:
721 		memcpy((char *)&pp->refid, REFID_DCF77, 4);
722 		break;
723 	    case 3:
724 		memcpy((char *)&pp->refid, REFID_WWVB, 4);
725 		break;
726 	    default:
727 		memcpy((char *)&pp->refid, REFID, 4);
728 		break;
729 	}
730 	/* Spread out resyncs so that they should remain separated. */
731 	up->next_resync = current_time + INITIAL_RESYNC_DELAY + (67*unit)%1009;
732 
733 #if 0 /* Not needed because of zeroing of arcunit structure... */
734 	up->resyncing = 0;              /* Not resyncing yet. */
735 	up->saved_flags = 0;            /* Default is all flags off. */
736 	/* Clear send buffer out... */
737 	{
738 		int i;
739 		for(i = CMDQUEUELEN; i >= 0; --i) { up->cmdqueue[i] = '\0'; }
740 	}
741 #endif
742 
743 #ifdef ARCRON_KEEN
744 	up->quality = QUALITY_UNKNOWN;  /* Trust the clock immediately. */
745 #else
746 	up->quality = MIN_CLOCK_QUALITY;/* Don't trust the clock yet. */
747 #endif
748 
749 	peer->action = arc_event_handler;
750 
751 	ENQUEUE(up);
752 
753 	return(1);
754 }
755 
756 
757 /*
758  * arc_shutdown - shut down the clock
759  */
760 static void
761 arc_shutdown(
762 	int unit,
763 	struct peer *peer
764 	)
765 {
766 	register struct arcunit *up;
767 	struct refclockproc *pp;
768 
769 	peer->action = dummy_event_handler;
770 
771 	pp = peer->procptr;
772 	up = (struct arcunit *)pp->unitptr;
773 	io_closeclock(&pp->io);
774 	free(up);
775 }
776 
777 /*
778 Compute space left in output buffer.
779 */
780 static int
781 space_left(
782 	register struct arcunit *up
783 	)
784 {
785 	int spaceleft;
786 
787 	/* Compute space left in buffer after any pending output. */
788 	for(spaceleft = 0; spaceleft < CMDQUEUELEN; ++spaceleft)
789 	{ if(up->cmdqueue[CMDQUEUELEN - 1 - spaceleft] != '\0') { break; } }
790 	return(spaceleft);
791 }
792 
793 /*
794 Send command by copying into command buffer as far forward as possible,
795 after any pending output.
796 
797 Indicate an error by returning 0 if there is not space for the command.
798 */
799 static int
800 send_slow(
801 	register struct arcunit *up,
802 	int fd,
803 	const char *s
804 	)
805 {
806 	int sl = strlen(s);
807 	int spaceleft = space_left(up);
808 
809 #ifdef DEBUG
810 	if(debug > 1) { printf("arc: spaceleft = %d.\n", spaceleft); }
811 #endif
812 	if(spaceleft < sl) { /* Should not normally happen... */
813 #ifdef DEBUG
814 		msyslog(LOG_NOTICE, "ARCRON: send-buffer overrun (%d/%d)",
815 		       sl, spaceleft);
816 #endif
817 		return(0);                      /* FAILED! */
818 	}
819 
820 	/* Copy in the command to be sent. */
821 	while(*s && spaceleft > 0) { up->cmdqueue[CMDQUEUELEN - spaceleft--] = *s++; }
822 
823 	return(1);
824 }
825 
826 
827 static int
828 get2(char *p, int *val)
829 {
830   if (!isdigit((int)p[0]) || !isdigit((int)p[1])) return 0;
831   *val = (p[0] - '0') * 10 + p[1] - '0';
832   return 1;
833 }
834 
835 static int
836 get1(char *p, int *val)
837 {
838   if (!isdigit((int)p[0])) return 0;
839   *val = p[0] - '0';
840   return 1;
841 }
842 
843 /* Macro indicating action we will take for different quality values. */
844 #define quality_action(q) \
845 (((q) == QUALITY_UNKNOWN) ?         "UNKNOWN, will use clock anyway" : \
846  (((q) < MIN_CLOCK_QUALITY_OK) ? "TOO POOR, will not use clock" : \
847   "OK, will use clock"))
848 
849      /*
850  * arc_receive - receive data from the serial interface
851  */
852      static void
853 arc_receive(
854 	struct recvbuf *rbufp
855 	)
856 {
857 	register struct arcunit *up;
858 	struct refclockproc *pp;
859 	struct peer *peer;
860 	char c;
861 	int i, n, wday, month, flags, status;
862 	int arc_last_offset;
863 	static int quality_average = 0;
864 	static int quality_sum = 0;
865 	static int quality_polls = 0;
866 
867 	/*
868 	 * Initialize pointers and read the timecode and timestamp
869 	 */
870 	peer = (struct peer *)rbufp->recv_srcclock;
871 	pp = peer->procptr;
872 	up = (struct arcunit *)pp->unitptr;
873 
874 
875 	/*
876 	  If the command buffer is empty, and we are resyncing, insert a
877 	  g\r quality request into it to poll for signal quality again.
878 	*/
879 	if((up->resyncing) && (space_left(up) == CMDQUEUELEN)) {
880 #ifdef DEBUG
881 		if(debug > 1) { printf("arc: inserting signal-quality poll.\n"); }
882 #endif
883 		send_slow(up, pp->io.fd, "g\r");
884 	}
885 
886 	/*
887 	  The `arc_last_offset' is the offset in lastcode[] of the last byte
888 	  received, and which we assume actually received the input
889 	  timestamp.
890 
891 	  (When we get round to using tty_clk and it is available, we
892 	  assume that we will receive the whole timecode with the
893 	  trailing \r, and that that \r will be timestamped.  But this
894 	  assumption also works if receive the characters one-by-one.)
895 	*/
896 	arc_last_offset = pp->lencode+rbufp->recv_length - 1;
897 
898 	/*
899 	  We catch a timestamp iff:
900 
901 	  * The command code is `o' for a timestamp.
902 
903 	  * If ARCRON_MULTIPLE_SAMPLES is undefined then we must have
904 	  exactly char in the buffer (the command code) so that we
905 	  only sample the first character of the timecode as our
906 	  `on-time' character.
907 
908 	  * The first character in the buffer is not the echoed `\r'
909 	  from the `o` command (so if we are to timestamp an `\r' it
910 	  must not be first in the receive buffer with lencode==1.
911 	  (Even if we had other characters following it, we probably
912 	  would have a premature timestamp on the '\r'.)
913 
914 	  * We have received at least one character (I cannot imagine
915 	  how it could be otherwise, but anyway...).
916 	*/
917 	c = rbufp->recv_buffer[0];
918 	if((pp->a_lastcode[0] == 'o') &&
919 #ifndef ARCRON_MULTIPLE_SAMPLES
920 	   (pp->lencode == 1) &&
921 #endif
922 	   ((pp->lencode != 1) || (c != '\r')) &&
923 	   (arc_last_offset >= 1)) {
924 		/* Note that the timestamp should be corrected if >1 char rcvd. */
925 		l_fp timestamp;
926 		timestamp = rbufp->recv_time;
927 #ifdef DEBUG
928 		if(debug) { /* Show \r as `R', other non-printing char as `?'. */
929 			printf("arc: stamp -->%c<-- (%d chars rcvd)\n",
930 			       ((c == '\r') ? 'R' : (isgraph((int)c) ? c : '?')),
931 			       rbufp->recv_length);
932 		}
933 #endif
934 
935 		/*
936 		  Now correct timestamp by offset of last byte received---we
937 		  subtract from the receive time the delay implied by the
938 		  extra characters received.
939 
940 		  Reject the input if the resulting code is too long, but
941 		  allow for the trailing \r, normally not used but a good
942 		  handle for tty_clk or somesuch kernel timestamper.
943 		*/
944 		if(arc_last_offset > LENARC) {
945 #ifdef DEBUG
946 			if(debug) {
947 				printf("arc: input code too long (%d cf %d); rejected.\n",
948 				       arc_last_offset, LENARC);
949 			}
950 #endif
951 			pp->lencode = 0;
952 			refclock_report(peer, CEVNT_BADREPLY);
953 			return;
954 		}
955 
956 		L_SUBUF(&timestamp, charoffsets[arc_last_offset]);
957 #ifdef DEBUG
958 		if(debug > 1) {
959 			printf(
960 				"arc: %s%d char(s) rcvd, the last for lastcode[%d]; -%sms offset applied.\n",
961 				((rbufp->recv_length > 1) ? "*** " : ""),
962 				rbufp->recv_length,
963 				arc_last_offset,
964 				mfptoms((unsigned long)0,
965 					charoffsets[arc_last_offset],
966 					1));
967 		}
968 #endif
969 
970 #ifdef ARCRON_MULTIPLE_SAMPLES
971 		/*
972 		  If taking multiple samples, capture the current adjusted
973 		  sample iff:
974 
975 		  * No timestamp has yet been captured (it is zero), OR
976 
977 		  * This adjusted timestamp is earlier than the one already
978 		  captured, on the grounds that this one suffered less
979 		  delay in being delivered to us and is more accurate.
980 
981 		*/
982 		if(L_ISZERO(&(up->lastrec)) ||
983 		   L_ISGEQ(&(up->lastrec), &timestamp))
984 #endif
985 		{
986 #ifdef DEBUG
987 			if(debug > 1) {
988 				printf("arc: system timestamp captured.\n");
989 #ifdef ARCRON_MULTIPLE_SAMPLES
990 				if(!L_ISZERO(&(up->lastrec))) {
991 					l_fp diff;
992 					diff = up->lastrec;
993 					L_SUB(&diff, &timestamp);
994 					printf("arc: adjusted timestamp by -%sms.\n",
995 					       mfptoms(diff.l_i, diff.l_f, 3));
996 				}
997 #endif
998 			}
999 #endif
1000 			up->lastrec = timestamp;
1001 		}
1002 
1003 	}
1004 
1005 	/* Just in case we still have lots of rubbish in the buffer... */
1006 	/* ...and to avoid the same timestamp being reused by mistake, */
1007 	/* eg on receipt of the \r coming in on its own after the      */
1008 	/* timecode.                                                   */
1009 	if(pp->lencode >= LENARC) {
1010 #ifdef DEBUG
1011 		if(debug && (rbufp->recv_buffer[0] != '\r'))
1012 		{ printf("arc: rubbish in pp->a_lastcode[].\n"); }
1013 #endif
1014 		pp->lencode = 0;
1015 		return;
1016 	}
1017 
1018 	/* Append input to code buffer, avoiding overflow. */
1019 	for(i = 0; i < rbufp->recv_length; i++) {
1020 		if(pp->lencode >= LENARC) { break; } /* Avoid overflow... */
1021 		c = rbufp->recv_buffer[i];
1022 
1023 		/* Drop trailing '\r's and drop `h' command echo totally. */
1024 		if(c != '\r' && c != 'h') { pp->a_lastcode[pp->lencode++] = c; }
1025 
1026 		/*
1027 		  If we've just put an `o' in the lastcode[0], clear the
1028 		  timestamp in anticipation of a timecode arriving soon.
1029 
1030 		  We would expect to get to process this before any of the
1031 		  timecode arrives.
1032 		*/
1033 		if((c == 'o') && (pp->lencode == 1)) {
1034 			L_CLR(&(up->lastrec));
1035 #ifdef DEBUG
1036 			if(debug > 1) { printf("arc: clearing timestamp.\n"); }
1037 #endif
1038 		}
1039 	}
1040 	if (pp->lencode == 0) return;
1041 
1042 	/* Handle a quality message. */
1043 	if(pp->a_lastcode[0] == 'g') {
1044 		int r, q;
1045 
1046 		if(pp->lencode < 3) { return; } /* Need more data... */
1047 		r = (pp->a_lastcode[1] & 0x7f); /* Strip parity. */
1048 		q = (pp->a_lastcode[2] & 0x7f); /* Strip parity. */
1049 		if(((q & 0x70) != 0x30) || ((q & 0xf) > MAX_CLOCK_QUALITY) ||
1050 		   ((r & 0x70) != 0x30)) {
1051 			/* Badly formatted response. */
1052 #ifdef DEBUG
1053 			if(debug) { printf("arc: bad `g' response %2x %2x.\n", r, q); }
1054 #endif
1055 			return;
1056 		}
1057 		if(r == '3') { /* Only use quality value whilst sync in progress. */
1058 			if (up->quality_stamp < current_time) {
1059 				struct calendar cal;
1060 				l_fp new_stamp;
1061 
1062 				get_systime (&new_stamp);
1063 				caljulian (new_stamp.l_ui, &cal);
1064 				up->quality_stamp =
1065 					current_time + 60 - cal.second + 5;
1066 				quality_sum = 0;
1067 				quality_polls = 0;
1068 			}
1069 			quality_sum += (q & 0xf);
1070 			quality_polls++;
1071 			quality_average = (quality_sum / quality_polls);
1072 #ifdef DEBUG
1073 			if(debug) { printf("arc: signal quality %d (%d).\n", quality_average, (q & 0xf)); }
1074 #endif
1075 		} else if( /* (r == '2') && */ up->resyncing) {
1076 			up->quality = quality_average;
1077 #ifdef DEBUG
1078 			if(debug)
1079 			{
1080 				printf("arc: sync finished, signal quality %d: %s\n",
1081 				       up->quality,
1082 				       quality_action(up->quality));
1083 			}
1084 #endif
1085 			msyslog(LOG_NOTICE,
1086 			       "ARCRON: sync finished, signal quality %d: %s",
1087 			       up->quality,
1088 			       quality_action(up->quality));
1089 			up->resyncing = 0; /* Resync is over. */
1090 			quality_average = 0;
1091 			quality_sum = 0;
1092 			quality_polls = 0;
1093 
1094 #ifdef ARCRON_KEEN
1095 			/* Clock quality dubious; resync earlier than usual. */
1096 			if((up->quality == QUALITY_UNKNOWN) ||
1097 			   (up->quality < MIN_CLOCK_QUALITY_OK))
1098 			{ up->next_resync = current_time + RETRY_RESYNC_TIME; }
1099 #endif
1100 		}
1101 		pp->lencode = 0;
1102 		return;
1103 	}
1104 
1105 	/* Stop now if this is not a timecode message. */
1106 	if(pp->a_lastcode[0] != 'o') {
1107 		pp->lencode = 0;
1108 		refclock_report(peer, CEVNT_BADREPLY);
1109 		return;
1110 	}
1111 
1112 	/* If we don't have enough data, wait for more... */
1113 	if(pp->lencode < LENARC) { return; }
1114 
1115 
1116 	/* WE HAVE NOW COLLECTED ONE TIMESTAMP (phew)... */
1117 #ifdef DEBUG
1118 	if(debug > 1) { printf("arc: NOW HAVE TIMESTAMP...\n"); }
1119 #endif
1120 
1121 	/* But check that we actually captured a system timestamp on it. */
1122 	if(L_ISZERO(&(up->lastrec))) {
1123 #ifdef DEBUG
1124 		if(debug) { printf("arc: FAILED TO GET SYSTEM TIMESTAMP\n"); }
1125 #endif
1126 		pp->lencode = 0;
1127 		refclock_report(peer, CEVNT_BADREPLY);
1128 		return;
1129 	}
1130 	/*
1131 	  Append a mark of the clock's received signal quality for the
1132 	  benefit of Derek Mulcahy's Tcl/Tk utility (we map the `unknown'
1133 	  quality value to `6' for his s/w) and terminate the string for
1134 	  sure.  This should not go off the buffer end.
1135 	*/
1136 	pp->a_lastcode[pp->lencode] = ((up->quality == QUALITY_UNKNOWN) ?
1137 				       '6' : ('0' + up->quality));
1138 	pp->a_lastcode[pp->lencode + 1] = '\0'; /* Terminate for printf(). */
1139 
1140 #ifdef PRE_NTP420
1141 	/* We don't use the micro-/milli- second part... */
1142 	pp->usec = 0;
1143 	pp->msec = 0;
1144 #else
1145 	/* We don't use the nano-second part... */
1146 	pp->nsec = 0;
1147 #endif
1148 	/* Validate format and numbers. */
1149 	if (pp->a_lastcode[0] != 'o'
1150 		|| !get2(pp->a_lastcode + 1, &pp->hour)
1151 		|| !get2(pp->a_lastcode + 3, &pp->minute)
1152 		|| !get2(pp->a_lastcode + 5, &pp->second)
1153 		|| !get1(pp->a_lastcode + 7, &wday)
1154 		|| !get2(pp->a_lastcode + 8, &pp->day)
1155 		|| !get2(pp->a_lastcode + 10, &month)
1156 		|| !get2(pp->a_lastcode + 12, &pp->year)) {
1157 #ifdef DEBUG
1158 		/* Would expect to have caught major problems already... */
1159 		if(debug) { printf("arc: badly formatted data.\n"); }
1160 #endif
1161 		pp->lencode = 0;
1162 		refclock_report(peer, CEVNT_BADREPLY);
1163 		return;
1164 	}
1165 	flags = pp->a_lastcode[14];
1166 	status = pp->a_lastcode[15];
1167 #ifdef DEBUG
1168 	if(debug) { printf("arc: status 0x%.2x flags 0x%.2x\n", flags, status); }
1169 #endif
1170 	n = 9;
1171 
1172 	/*
1173 	  Validate received values at least enough to prevent internal
1174 	  array-bounds problems, etc.
1175 	*/
1176 	if((pp->hour < 0) || (pp->hour > 23) ||
1177 	   (pp->minute < 0) || (pp->minute > 59) ||
1178 	   (pp->second < 0) || (pp->second > 60) /*Allow for leap seconds.*/ ||
1179 	   (wday < 1) || (wday > 7) ||
1180 	   (pp->day < 1) || (pp->day > 31) ||
1181 	   (month < 1) || (month > 12) ||
1182 	   (pp->year < 0) || (pp->year > 99)) {
1183 		/* Data out of range. */
1184 		pp->lencode = 0;
1185 		refclock_report(peer, CEVNT_BADREPLY);
1186 		return;
1187 	}
1188 
1189 
1190 	if(peer->MODE == 0) { /* compatiblity to original version */
1191 		int bst = flags;
1192 		/* Check that BST/UTC bits are the complement of one another. */
1193 		if(!(bst & 2) == !(bst & 4)) {
1194 			pp->lencode = 0;
1195 			refclock_report(peer, CEVNT_BADREPLY);
1196 			return;
1197 		}
1198 	}
1199 	if(status & 0x8) { msyslog(LOG_NOTICE, "ARCRON: battery low"); }
1200 
1201 	/* Year-2000 alert! */
1202 	/* Attempt to wrap 2-digit date into sensible window. */
1203 	if(pp->year < YEAR_PIVOT) { pp->year += 100; }		/* Y2KFixes */
1204 	pp->year += 1900;	/* use full four-digit year */	/* Y2KFixes */
1205 	/*
1206 	  Attempt to do the right thing by screaming that the code will
1207 	  soon break when we get to the end of its useful life.  What a
1208 	  hero I am...  PLEASE FIX LEAP-YEAR AND WRAP CODE IN 209X!
1209 	*/
1210 	if(pp->year >= YEAR_PIVOT+2000-2 ) {  			/* Y2KFixes */
1211 		/*This should get attention B^> */
1212 		msyslog(LOG_NOTICE,
1213 		       "ARCRON: fix me!  EITHER YOUR DATE IS BADLY WRONG or else I will break soon!");
1214 	}
1215 #ifdef DEBUG
1216 	if(debug) {
1217 		printf("arc: n=%d %02d:%02d:%02d %02d/%02d/%04d %1d %1d\n",
1218 		       n,
1219 		       pp->hour, pp->minute, pp->second,
1220 		       pp->day, month, pp->year, flags, status);
1221 	}
1222 #endif
1223 
1224 	/*
1225 	  The status value tested for is not strictly supported by the
1226 	  clock spec since the value of bit 2 (0x4) is claimed to be
1227 	  undefined for MSF, yet does seem to indicate if the last resync
1228 	  was successful or not.
1229 	*/
1230 	pp->leap = LEAP_NOWARNING;
1231 	status &= 0x7;
1232 	if(status == 0x3) {
1233 		if(status != up->status)
1234 		{ msyslog(LOG_NOTICE, "ARCRON: signal acquired"); }
1235 	} else {
1236 		if(status != up->status) {
1237 			msyslog(LOG_NOTICE, "ARCRON: signal lost");
1238 			pp->leap = LEAP_NOTINSYNC; /* MSF clock is free-running. */
1239 			up->status = status;
1240 			pp->lencode = 0;
1241 			refclock_report(peer, CEVNT_FAULT);
1242 			return;
1243 		}
1244 	}
1245 	up->status = status;
1246 
1247 	if (peer->MODE == 0) { /* compatiblity to original version */
1248 		int bst = flags;
1249 
1250 		pp->day += moff[month - 1];
1251 
1252 		if(isleap_4(pp->year) && month > 2) { pp->day++; }/* Y2KFixes */
1253 
1254 		/* Convert to UTC if required */
1255 		if(bst & 2) {
1256 			pp->hour--;
1257 			if (pp->hour < 0) {
1258 				pp->hour = 23;
1259 				pp->day--;
1260 				/* If we try to wrap round the year
1261 				 * (BST on 1st Jan), reject.*/
1262 				if(pp->day < 0) {
1263 					pp->lencode = 0;
1264 					refclock_report(peer, CEVNT_BADTIME);
1265 					return;
1266 				}
1267 			}
1268 		}
1269 	}
1270 
1271 	if(peer->MODE > 0) {
1272 		if(pp->sloppyclockflag & CLK_FLAG1) {
1273 			struct tm  local;
1274 		        struct tm *gmtp;
1275 		        time_t     unixtime;
1276 
1277 		        /*
1278 		         * Convert to GMT for sites that distribute localtime.
1279 			 * This means we have to do Y2K conversion on the
1280 			 * 2-digit year; otherwise, we get the time wrong.
1281 	        	 */
1282 
1283 			local.tm_year  = pp->year-1900;
1284 	     	  	local.tm_mon   = month-1;
1285 	      	  	local.tm_mday  = pp->day;
1286 	        	local.tm_hour  = pp->hour;
1287 	        	local.tm_min   = pp->minute;
1288 	        	local.tm_sec   = pp->second;
1289 	        	switch (peer->MODE) {
1290 			    case 1:
1291 				local.tm_isdst = (flags & 2);
1292 				break;
1293 			    case 2:
1294 			        local.tm_isdst = (flags & 2);
1295 				break;
1296 			    case 3:
1297 				switch (flags & 3) {
1298 				    case 0: /* It is unclear exactly when the
1299 				    	       Arcron changes from DST->ST and
1300 					       ST->DST. Testing has shown this
1301 					       to be irregular. For the time
1302 					       being, let the OS decide. */
1303 				        local.tm_isdst = 0;
1304 #ifdef DEBUG
1305 					if (debug)
1306 					    printf ("arc: DST = 00 (0)\n");
1307 #endif
1308 					break;
1309 				    case 1: /* dst->st time */
1310 				        local.tm_isdst = -1;
1311 #ifdef DEBUG
1312 					if (debug)
1313 					    printf ("arc: DST = 01 (1)\n");
1314 #endif
1315 					break;
1316 				    case 2: /* st->dst time */
1317 				        local.tm_isdst = -1;
1318 #ifdef DEBUG
1319 					if (debug)
1320 					    printf ("arc: DST = 10 (2)\n");
1321 #endif
1322 					break;
1323 				    case 3: /* dst time */
1324 				        local.tm_isdst = 1;
1325 #ifdef DEBUG
1326 					if (debug)
1327 					    printf ("arc: DST = 11 (3)\n");
1328 #endif
1329 					break;
1330 				}
1331 				break;
1332 			    default:
1333 				msyslog(LOG_NOTICE, "ARCRON: Invalid mode %d",
1334 		      			peer->MODE);
1335 				return;
1336 				break;
1337 			}
1338 	        	unixtime = mktime (&local);
1339 	        	if ((gmtp = gmtime (&unixtime)) == NULL)
1340 	        	{
1341 				pp->lencode = 0;
1342 			        refclock_report (peer, CEVNT_FAULT);
1343 			        return;
1344 	        	}
1345 			pp->year = gmtp->tm_year+1900;
1346 	        	month = gmtp->tm_mon+1;
1347 		    	pp->day = ymd2yd(pp->year,month,gmtp->tm_mday);
1348 	       	 	/* pp->day = gmtp->tm_yday; */
1349 	        	pp->hour = gmtp->tm_hour;
1350 	        	pp->minute = gmtp->tm_min;
1351 	        	pp->second = gmtp->tm_sec;
1352 #ifdef DEBUG
1353 	        	if (debug)
1354 			{
1355 				printf ("arc: time is %04d/%02d/%02d %02d:%02d:%02d UTC\n",
1356 					pp->year,month,gmtp->tm_mday,pp->hour,pp->minute,
1357 					pp->second);
1358 			}
1359 #endif
1360 		} else
1361 		{
1362 		    	/*
1363 		     	* For more rational sites distributing UTC
1364 		     	*/
1365 		    	pp->day    = ymd2yd(pp->year,month,pp->day);
1366 		}
1367 	}
1368 
1369 	if (peer->MODE == 0) { /* compatiblity to original version */
1370 				/* If clock signal quality is
1371 				 * unknown, revert to default PRECISION...*/
1372 		if(up->quality == QUALITY_UNKNOWN) {
1373 			peer->precision = PRECISION;
1374 		} else { /* ...else improve precision if flag3 is set... */
1375 			peer->precision = ((pp->sloppyclockflag & CLK_FLAG3) ?
1376 					   HIGHPRECISION : PRECISION);
1377 		}
1378 	} else {
1379 		if ((status == 0x3) && (pp->sloppyclockflag & CLK_FLAG2)) {
1380 			peer->precision = ((pp->sloppyclockflag & CLK_FLAG3) ?
1381 					   HIGHPRECISION : PRECISION);
1382 		} else if (up->quality == QUALITY_UNKNOWN) {
1383 			peer->precision = PRECISION;
1384 		} else {
1385 			peer->precision = ((pp->sloppyclockflag & CLK_FLAG3) ?
1386 					   HIGHPRECISION : PRECISION);
1387 		}
1388 	}
1389 
1390 	/* Notice and log any change (eg from initial defaults) for flags. */
1391 	if(up->saved_flags != pp->sloppyclockflag) {
1392 #ifdef DEBUG
1393 		msyslog(LOG_NOTICE, "ARCRON: flags enabled: %s%s%s%s",
1394 		       ((pp->sloppyclockflag & CLK_FLAG1) ? "1" : "."),
1395 		       ((pp->sloppyclockflag & CLK_FLAG2) ? "2" : "."),
1396 		       ((pp->sloppyclockflag & CLK_FLAG3) ? "3" : "."),
1397 		       ((pp->sloppyclockflag & CLK_FLAG4) ? "4" : "."));
1398 		/* Note effects of flags changing... */
1399 		if(debug) {
1400 			printf("arc: PRECISION = %d.\n", peer->precision);
1401 		}
1402 #endif
1403 		up->saved_flags = pp->sloppyclockflag;
1404 	}
1405 
1406 	/* Note time of last believable timestamp. */
1407 	pp->lastrec = up->lastrec;
1408 
1409 #ifdef ARCRON_LEAPSECOND_KEEN
1410 	/* Find out if a leap-second might just have happened...
1411 	   (ie is this the first hour of the first day of Jan or Jul?)
1412 	*/
1413 	if((pp->hour == 0) &&
1414 	   (pp->day == 1) &&
1415 	   ((month == 1) || (month == 7))) {
1416 		if(possible_leap >= 0) {
1417 			/* A leap may have happened, and no resync has started yet...*/
1418 			possible_leap = 1;
1419 		}
1420 	} else {
1421 		/* Definitely not leap-second territory... */
1422 		possible_leap = 0;
1423 	}
1424 #endif
1425 
1426 	if (!refclock_process(pp)) {
1427 		pp->lencode = 0;
1428 		refclock_report(peer, CEVNT_BADTIME);
1429 		return;
1430 	}
1431 	record_clock_stats(&peer->srcadr, pp->a_lastcode);
1432 	refclock_receive(peer);
1433 }
1434 
1435 
1436 /* request_time() sends a time request to the clock with given peer. */
1437 /* This automatically reports a fault if necessary. */
1438 /* No data should be sent after this until arc_poll() returns. */
1439 static  void    request_time    P((int, struct peer *));
1440 static void
1441 request_time(
1442 	int unit,
1443 	struct peer *peer
1444 	)
1445 {
1446 	struct refclockproc *pp = peer->procptr;
1447 	register struct arcunit *up = (struct arcunit *)pp->unitptr;
1448 #ifdef DEBUG
1449 	if(debug) { printf("arc: unit %d: requesting time.\n", unit); }
1450 #endif
1451 	if (!send_slow(up, pp->io.fd, "o\r")) {
1452 #ifdef DEBUG
1453 		if (debug) {
1454 			printf("arc: unit %d: problem sending", unit);
1455 		}
1456 #endif
1457 		pp->lencode = 0;
1458 		refclock_report(peer, CEVNT_FAULT);
1459 		return;
1460 	}
1461 	pp->polls++;
1462 }
1463 
1464 /*
1465  * arc_poll - called by the transmit procedure
1466  */
1467 static void
1468 arc_poll(
1469 	int unit,
1470 	struct peer *peer
1471 	)
1472 {
1473 	register struct arcunit *up;
1474 	struct refclockproc *pp;
1475 	int resync_needed;              /* Should we start a resync? */
1476 
1477 	pp = peer->procptr;
1478 	up = (struct arcunit *)pp->unitptr;
1479 #if 0
1480 	pp->lencode = 0;
1481 	memset(pp->a_lastcode, 0, sizeof(pp->a_lastcode));
1482 #endif
1483 
1484 #if 0
1485 	/* Flush input. */
1486 	tcflush(pp->io.fd, TCIFLUSH);
1487 #endif
1488 
1489 	/* Resync if our next scheduled resync time is here or has passed. */
1490 	resync_needed = ( !(pp->sloppyclockflag & CLK_FLAG2) &&
1491 			  (up->next_resync <= current_time) );
1492 
1493 #ifdef ARCRON_LEAPSECOND_KEEN
1494 	/*
1495 	  Try to catch a potential leap-second insertion or deletion quickly.
1496 
1497 	  In addition to the normal NTP fun of clocks that don't report
1498 	  leap-seconds spooking their hosts, this clock does not even
1499 	  sample the radio sugnal the whole time, so may miss a
1500 	  leap-second insertion or deletion for up to a whole sample
1501 	  time.
1502 
1503 	  To try to minimise this effect, if in the first few minutes of
1504 	  the day immediately following a leap-second-insertion point
1505 	  (ie in the first hour of the first day of the first and sixth
1506 	  months), and if the last resync was in the previous day, and a
1507 	  resync is not already in progress, resync the clock
1508 	  immediately.
1509 
1510 	*/
1511 	if((possible_leap > 0) &&       /* Must be 00:XX 01/0{1,7}/XXXX. */
1512 	   (!up->resyncing)) {          /* No resync in progress yet. */
1513 		resync_needed = 1;
1514 		possible_leap = -1;          /* Prevent multiple resyncs. */
1515 		msyslog(LOG_NOTICE,"ARCRON: unit %d: checking for leap second",unit);
1516 	}
1517 #endif
1518 
1519 	/* Do a resync if required... */
1520 	if(resync_needed) {
1521 		/* First, reset quality value to `unknown' so we can detect */
1522 		/* when a quality message has been responded to by this     */
1523 		/* being set to some other value.                           */
1524 		up->quality = QUALITY_UNKNOWN;
1525 
1526 		/* Note that we are resyncing... */
1527 		up->resyncing = 1;
1528 
1529 		/* Now actually send the resync command and an immediate poll. */
1530 #ifdef DEBUG
1531 		if(debug) { printf("arc: sending resync command (h\\r).\n"); }
1532 #endif
1533 		msyslog(LOG_NOTICE, "ARCRON: unit %d: sending resync command", unit);
1534 		send_slow(up, pp->io.fd, "h\r");
1535 
1536 		/* Schedule our next resync... */
1537 		up->next_resync = current_time + DEFAULT_RESYNC_TIME;
1538 
1539 		/* Drop through to request time if appropriate. */
1540 	}
1541 
1542 	/* If clock quality is too poor to trust, indicate a fault. */
1543 	/* If quality is QUALITY_UNKNOWN and ARCRON_KEEN is defined,*/
1544 	/* we'll cross our fingers and just hope that the thing     */
1545 	/* synced so quickly we did not catch it---we'll            */
1546 	/* double-check the clock is OK elsewhere.                  */
1547 	if(
1548 #ifdef ARCRON_KEEN
1549 		(up->quality != QUALITY_UNKNOWN) &&
1550 #else
1551 		(up->quality == QUALITY_UNKNOWN) ||
1552 #endif
1553 		(up->quality < MIN_CLOCK_QUALITY_OK)) {
1554 #ifdef DEBUG
1555 		if(debug) {
1556 			printf("arc: clock quality %d too poor.\n", up->quality);
1557 		}
1558 #endif
1559 		pp->lencode = 0;
1560 		refclock_report(peer, CEVNT_FAULT);
1561 		return;
1562 	}
1563 	/* This is the normal case: request a timestamp. */
1564 	request_time(unit, peer);
1565 }
1566 
1567 #else
1568 int refclock_arc_bs;
1569 #endif
1570