refclock_wwvb.c revision 290001
1/* 2 * refclock_wwvb - clock driver for Spectracom WWVB and GPS receivers 3 */ 4 5#ifdef HAVE_CONFIG_H 6#include <config.h> 7#endif 8 9#if defined(REFCLOCK) && defined(CLOCK_SPECTRACOM) 10 11#include "ntpd.h" 12#include "ntp_io.h" 13#include "ntp_refclock.h" 14#include "ntp_calendar.h" 15#include "ntp_stdlib.h" 16 17#include <stdio.h> 18#include <ctype.h> 19 20#ifdef HAVE_PPSAPI 21#include "ppsapi_timepps.h" 22#include "refclock_atom.h" 23#endif /* HAVE_PPSAPI */ 24 25/* 26 * This driver supports the Spectracom Model 8170 and Netclock/2 WWVB 27 * Synchronized Clocks and the Netclock/GPS Master Clock. Both the WWVB 28 * and GPS clocks have proven reliable sources of time; however, the 29 * WWVB clocks have proven vulnerable to high ambient conductive RF 30 * interference. The claimed accuracy of the WWVB clocks is 100 us 31 * relative to the broadcast signal, while the claimed accuracy of the 32 * GPS clock is 50 ns; however, in most cases the actual accuracy is 33 * limited by the resolution of the timecode and the latencies of the 34 * serial interface and operating system. 35 * 36 * The WWVB and GPS clocks should be configured for 24-hour display, 37 * AUTO DST off, time zone 0 (UTC), data format 0 or 2 (see below) and 38 * baud rate 9600. If the clock is to used as the source for the IRIG 39 * Audio Decoder (refclock_irig.c in this distribution), it should be 40 * configured for AM IRIG output and IRIG format 1 (IRIG B with 41 * signature control). The GPS clock can be configured either to respond 42 * to a 'T' poll character or left running continuously. 43 * 44 * There are two timecode formats used by these clocks. Format 0, which 45 * is available with both the Netclock/2 and 8170, and format 2, which 46 * is available only with the Netclock/2, specially modified 8170 and 47 * GPS. 48 * 49 * Format 0 (22 ASCII printing characters): 50 * 51 * <cr><lf>i ddd hh:mm:ss TZ=zz<cr><lf> 52 * 53 * on-time = first <cr> 54 * hh:mm:ss = hours, minutes, seconds 55 * i = synchronization flag (' ' = in synch, '?' = out of synch) 56 * 57 * The alarm condition is indicated by other than ' ' at i, which occurs 58 * during initial synchronization and when received signal is lost for 59 * about ten hours. 60 * 61 * Format 2 (24 ASCII printing characters): 62 * 63 * <cr><lf>iqyy ddd hh:mm:ss.fff ld 64 * 65 * on-time = <cr> 66 * i = synchronization flag (' ' = in synch, '?' = out of synch) 67 * q = quality indicator (' ' = locked, 'A'...'D' = unlocked) 68 * yy = year (as broadcast) 69 * ddd = day of year 70 * hh:mm:ss.fff = hours, minutes, seconds, milliseconds 71 * 72 * The alarm condition is indicated by other than ' ' at i, which occurs 73 * during initial synchronization and when received signal is lost for 74 * about ten hours. The unlock condition is indicated by other than ' ' 75 * at q. 76 * 77 * The q is normally ' ' when the time error is less than 1 ms and a 78 * character in the set 'A'...'D' when the time error is less than 10, 79 * 100, 500 and greater than 500 ms respectively. The l is normally ' ', 80 * but is set to 'L' early in the month of an upcoming UTC leap second 81 * and reset to ' ' on the first day of the following month. The d is 82 * set to 'S' for standard time 'I' on the day preceding a switch to 83 * daylight time, 'D' for daylight time and 'O' on the day preceding a 84 * switch to standard time. The start bit of the first <cr> is 85 * synchronized to the indicated time as returned. 86 * 87 * This driver does not need to be told which format is in use - it 88 * figures out which one from the length of the message. The driver 89 * makes no attempt to correct for the intrinsic jitter of the radio 90 * itself, which is a known problem with the older radios. 91 * 92 * PPS Signal Processing 93 * 94 * When PPS signal processing is enabled, and when the system clock has 95 * been set by this or another driver and the PPS signal offset is 96 * within 0.4 s of the system clock offset, the PPS signal replaces the 97 * timecode for as long as the PPS signal is active. If for some reason 98 * the PPS signal fails for one or more poll intervals, the driver 99 * reverts to the timecode. If the timecode fails for one or more poll 100 * intervals, the PPS signal is disconnected. 101 * 102 * Fudge Factors 103 * 104 * This driver can retrieve a table of quality data maintained 105 * internally by the Netclock/2 clock. If flag4 of the fudge 106 * configuration command is set to 1, the driver will retrieve this 107 * table and write it to the clockstats file when the first timecode 108 * message of a new day is received. 109 * 110 * PPS calibration fudge time 1: format 0 .003134, format 2 .004034 111 */ 112/* 113 * Interface definitions 114 */ 115#define DEVICE "/dev/wwvb%d" /* device name and unit */ 116#define SPEED232 B9600 /* uart speed (9600 baud) */ 117#define PRECISION (-13) /* precision assumed (about 100 us) */ 118#define PPS_PRECISION (-13) /* precision assumed (about 100 us) */ 119#define REFID "WWVB" /* reference ID */ 120#define DESCRIPTION "Spectracom WWVB/GPS Receiver" /* WRU */ 121 122#define LENWWVB0 22 /* format 0 timecode length */ 123#define LENWWVB2 24 /* format 2 timecode length */ 124#define LENWWVB3 29 /* format 3 timecode length */ 125#define MONLIN 15 /* number of monitoring lines */ 126 127/* 128 * WWVB unit control structure 129 */ 130struct wwvbunit { 131#ifdef HAVE_PPSAPI 132 struct refclock_atom atom; /* PPSAPI structure */ 133 int ppsapi_tried; /* attempt PPSAPI once */ 134 int ppsapi_lit; /* time_pps_create() worked */ 135 int tcount; /* timecode sample counter */ 136 int pcount; /* PPS sample counter */ 137#endif /* HAVE_PPSAPI */ 138 l_fp laststamp; /* last <CR> timestamp */ 139 int prev_eol_cr; /* was last EOL <CR> (not <LF>)? */ 140 u_char lasthour; /* last hour (for monitor) */ 141 u_char linect; /* count ignored lines (for monitor */ 142}; 143 144/* 145 * Function prototypes 146 */ 147static int wwvb_start (int, struct peer *); 148static void wwvb_shutdown (int, struct peer *); 149static void wwvb_receive (struct recvbuf *); 150static void wwvb_poll (int, struct peer *); 151static void wwvb_timer (int, struct peer *); 152#ifdef HAVE_PPSAPI 153static void wwvb_control (int, const struct refclockstat *, 154 struct refclockstat *, struct peer *); 155#define WWVB_CONTROL wwvb_control 156#else 157#define WWVB_CONTROL noentry 158#endif /* HAVE_PPSAPI */ 159 160/* 161 * Transfer vector 162 */ 163struct refclock refclock_wwvb = { 164 wwvb_start, /* start up driver */ 165 wwvb_shutdown, /* shut down driver */ 166 wwvb_poll, /* transmit poll message */ 167 WWVB_CONTROL, /* fudge set/change notification */ 168 noentry, /* initialize driver (not used) */ 169 noentry, /* not used (old wwvb_buginfo) */ 170 wwvb_timer /* called once per second */ 171}; 172 173 174/* 175 * wwvb_start - open the devices and initialize data for processing 176 */ 177static int 178wwvb_start( 179 int unit, 180 struct peer *peer 181 ) 182{ 183 register struct wwvbunit *up; 184 struct refclockproc *pp; 185 int fd; 186 char device[20]; 187 188 /* 189 * Open serial port. Use CLK line discipline, if available. 190 */ 191 snprintf(device, sizeof(device), DEVICE, unit); 192 fd = refclock_open(device, SPEED232, LDISC_CLK); 193 if (fd <= 0) 194 return (0); 195 196 /* 197 * Allocate and initialize unit structure 198 */ 199 up = emalloc_zero(sizeof(*up)); 200 pp = peer->procptr; 201 pp->io.clock_recv = wwvb_receive; 202 pp->io.srcclock = peer; 203 pp->io.datalen = 0; 204 pp->io.fd = fd; 205 if (!io_addclock(&pp->io)) { 206 close(fd); 207 pp->io.fd = -1; 208 free(up); 209 return (0); 210 } 211 pp->unitptr = up; 212 213 /* 214 * Initialize miscellaneous variables 215 */ 216 peer->precision = PRECISION; 217 pp->clockdesc = DESCRIPTION; 218 memcpy(&pp->refid, REFID, 4); 219 return (1); 220} 221 222 223/* 224 * wwvb_shutdown - shut down the clock 225 */ 226static void 227wwvb_shutdown( 228 int unit, 229 struct peer *peer 230 ) 231{ 232 struct refclockproc * pp; 233 struct wwvbunit * up; 234 235 pp = peer->procptr; 236 up = pp->unitptr; 237 if (-1 != pp->io.fd) 238 io_closeclock(&pp->io); 239 if (NULL != up) 240 free(up); 241} 242 243 244/* 245 * wwvb_receive - receive data from the serial interface 246 */ 247static void 248wwvb_receive( 249 struct recvbuf *rbufp 250 ) 251{ 252 struct wwvbunit *up; 253 struct refclockproc *pp; 254 struct peer *peer; 255 256 l_fp trtmp; /* arrival timestamp */ 257 int tz; /* time zone */ 258 int day, month; /* ddd conversion */ 259 int temp; /* int temp */ 260 char syncchar; /* synchronization indicator */ 261 char qualchar; /* quality indicator */ 262 char leapchar; /* leap indicator */ 263 char dstchar; /* daylight/standard indicator */ 264 char tmpchar; /* trashbin */ 265 266 /* 267 * Initialize pointers and read the timecode and timestamp 268 */ 269 peer = rbufp->recv_peer; 270 pp = peer->procptr; 271 up = pp->unitptr; 272 temp = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &trtmp); 273 274 /* 275 * Note we get a buffer and timestamp for both a <cr> and <lf>, 276 * but only the <cr> timestamp is retained. Note: in format 0 on 277 * a Netclock/2 or upgraded 8170 the start bit is delayed 100 278 * +-50 us relative to the pps; however, on an unmodified 8170 279 * the start bit can be delayed up to 10 ms. In format 2 the 280 * reading precision is only to the millisecond. Thus, unless 281 * you have a PPS gadget and don't have to have the year, format 282 * 0 provides the lowest jitter. 283 * Save the timestamp of each <CR> in up->laststamp. Lines with 284 * no characters occur for every <LF>, and for some <CR>s when 285 * format 0 is used. Format 0 starts and ends each cycle with a 286 * <CR><LF> pair, format 2 starts each cycle with its only pair. 287 * The preceding <CR> is the on-time character for both formats. 288 * The timestamp provided with non-empty lines corresponds to 289 * the <CR> following the timecode, which is ultimately not used 290 * with format 0 and is used for the following timecode for 291 * format 2. 292 */ 293 if (temp == 0) { 294 if (up->prev_eol_cr) { 295 DPRINTF(2, ("wwvb: <LF> @ %s\n", 296 prettydate(&trtmp))); 297 } else { 298 up->laststamp = trtmp; 299 DPRINTF(2, ("wwvb: <CR> @ %s\n", 300 prettydate(&trtmp))); 301 } 302 up->prev_eol_cr = !up->prev_eol_cr; 303 return; 304 } 305 pp->lencode = temp; 306 pp->lastrec = up->laststamp; 307 up->laststamp = trtmp; 308 up->prev_eol_cr = TRUE; 309 DPRINTF(2, ("wwvb: code @ %s\n" 310 " using %s minus one char\n", 311 prettydate(&trtmp), prettydate(&pp->lastrec))); 312 if (L_ISZERO(&pp->lastrec)) 313 return; 314 315 /* 316 * We get down to business, check the timecode format and decode 317 * its contents. This code uses the timecode length to determine 318 * format 0, 2 or 3. If the timecode has invalid length or is 319 * not in proper format, we declare bad format and exit. 320 */ 321 syncchar = qualchar = leapchar = dstchar = ' '; 322 tz = 0; 323 switch (pp->lencode) { 324 325 case LENWWVB0: 326 327 /* 328 * Timecode format 0: "I ddd hh:mm:ss DTZ=nn" 329 */ 330 if (sscanf(pp->a_lastcode, 331 "%c %3d %2d:%2d:%2d%c%cTZ=%2d", 332 &syncchar, &pp->day, &pp->hour, &pp->minute, 333 &pp->second, &tmpchar, &dstchar, &tz) == 8) { 334 pp->nsec = 0; 335 break; 336 } 337 goto bad_format; 338 339 case LENWWVB2: 340 341 /* 342 * Timecode format 2: "IQyy ddd hh:mm:ss.mmm LD" */ 343 if (sscanf(pp->a_lastcode, 344 "%c%c %2d %3d %2d:%2d:%2d.%3ld %c", 345 &syncchar, &qualchar, &pp->year, &pp->day, 346 &pp->hour, &pp->minute, &pp->second, &pp->nsec, 347 &leapchar) == 9) { 348 pp->nsec *= 1000000; 349 break; 350 } 351 goto bad_format; 352 353 case LENWWVB3: 354 355 /* 356 * Timecode format 3: "0003I yyyymmdd hhmmss+0000SL#" 357 * WARNING: Undocumented, and the on-time character # is 358 * not yet handled correctly by this driver. It may be 359 * as simple as compensating for an additional 1/960 s. 360 */ 361 if (sscanf(pp->a_lastcode, 362 "0003%c %4d%2d%2d %2d%2d%2d+0000%c%c", 363 &syncchar, &pp->year, &month, &day, &pp->hour, 364 &pp->minute, &pp->second, &dstchar, &leapchar) == 8) 365 { 366 pp->day = ymd2yd(pp->year, month, day); 367 pp->nsec = 0; 368 break; 369 } 370 goto bad_format; 371 372 default: 373 bad_format: 374 375 /* 376 * Unknown format: If dumping internal table, record 377 * stats; otherwise, declare bad format. 378 */ 379 if (up->linect > 0) { 380 up->linect--; 381 record_clock_stats(&peer->srcadr, 382 pp->a_lastcode); 383 } else { 384 refclock_report(peer, CEVNT_BADREPLY); 385 } 386 return; 387 } 388 389 /* 390 * Decode synchronization, quality and leap characters. If 391 * unsynchronized, set the leap bits accordingly and exit. 392 * Otherwise, set the leap bits according to the leap character. 393 * Once synchronized, the dispersion depends only on the 394 * quality character. 395 */ 396 switch (qualchar) { 397 398 case ' ': 399 pp->disp = .001; 400 pp->lastref = pp->lastrec; 401 break; 402 403 case 'A': 404 pp->disp = .01; 405 break; 406 407 case 'B': 408 pp->disp = .1; 409 break; 410 411 case 'C': 412 pp->disp = .5; 413 break; 414 415 case 'D': 416 pp->disp = MAXDISPERSE; 417 break; 418 419 default: 420 pp->disp = MAXDISPERSE; 421 refclock_report(peer, CEVNT_BADREPLY); 422 break; 423 } 424 if (syncchar != ' ') 425 pp->leap = LEAP_NOTINSYNC; 426 else if (leapchar == 'L') 427 pp->leap = LEAP_ADDSECOND; 428 else 429 pp->leap = LEAP_NOWARNING; 430 431 /* 432 * Process the new sample in the median filter and determine the 433 * timecode timestamp, but only if the PPS is not in control. 434 */ 435#ifdef HAVE_PPSAPI 436 up->tcount++; 437 if (peer->flags & FLAG_PPS) 438 return; 439 440#endif /* HAVE_PPSAPI */ 441 if (!refclock_process_f(pp, pp->fudgetime2)) 442 refclock_report(peer, CEVNT_BADTIME); 443} 444 445 446/* 447 * wwvb_timer - called once per second by the transmit procedure 448 */ 449static void 450wwvb_timer( 451 int unit, 452 struct peer *peer 453 ) 454{ 455 register struct wwvbunit *up; 456 struct refclockproc *pp; 457 char pollchar; /* character sent to clock */ 458#ifdef DEBUG 459 l_fp now; 460#endif 461 462 /* 463 * Time to poll the clock. The Spectracom clock responds to a 464 * 'T' by returning a timecode in the format(s) specified above. 465 * Note there is no checking on state, since this may not be the 466 * only customer reading the clock. Only one customer need poll 467 * the clock; all others just listen in. 468 */ 469 pp = peer->procptr; 470 up = pp->unitptr; 471 if (up->linect > 0) 472 pollchar = 'R'; 473 else 474 pollchar = 'T'; 475 if (write(pp->io.fd, &pollchar, 1) != 1) 476 refclock_report(peer, CEVNT_FAULT); 477#ifdef DEBUG 478 get_systime(&now); 479 if (debug) 480 printf("%c poll at %s\n", pollchar, prettydate(&now)); 481#endif 482#ifdef HAVE_PPSAPI 483 if (up->ppsapi_lit && 484 refclock_pps(peer, &up->atom, pp->sloppyclockflag) > 0) { 485 up->pcount++, 486 peer->flags |= FLAG_PPS; 487 peer->precision = PPS_PRECISION; 488 } 489#endif /* HAVE_PPSAPI */ 490} 491 492 493/* 494 * wwvb_poll - called by the transmit procedure 495 */ 496static void 497wwvb_poll( 498 int unit, 499 struct peer *peer 500 ) 501{ 502 register struct wwvbunit *up; 503 struct refclockproc *pp; 504 505 /* 506 * Sweep up the samples received since the last poll. If none 507 * are received, declare a timeout and keep going. 508 */ 509 pp = peer->procptr; 510 up = pp->unitptr; 511 pp->polls++; 512 513 /* 514 * If the monitor flag is set (flag4), we dump the internal 515 * quality table at the first timecode beginning the day. 516 */ 517 if (pp->sloppyclockflag & CLK_FLAG4 && pp->hour < 518 (int)up->lasthour) 519 up->linect = MONLIN; 520 up->lasthour = (u_char)pp->hour; 521 522 /* 523 * Process median filter samples. If none received, declare a 524 * timeout and keep going. 525 */ 526#ifdef HAVE_PPSAPI 527 if (up->pcount == 0) { 528 peer->flags &= ~FLAG_PPS; 529 peer->precision = PRECISION; 530 } 531 if (up->tcount == 0) { 532 pp->coderecv = pp->codeproc; 533 refclock_report(peer, CEVNT_TIMEOUT); 534 return; 535 } 536 up->pcount = up->tcount = 0; 537#else /* HAVE_PPSAPI */ 538 if (pp->coderecv == pp->codeproc) { 539 refclock_report(peer, CEVNT_TIMEOUT); 540 return; 541 } 542#endif /* HAVE_PPSAPI */ 543 refclock_receive(peer); 544 record_clock_stats(&peer->srcadr, pp->a_lastcode); 545#ifdef DEBUG 546 if (debug) 547 printf("wwvb: timecode %d %s\n", pp->lencode, 548 pp->a_lastcode); 549#endif 550} 551 552 553/* 554 * wwvb_control - fudge parameters have been set or changed 555 */ 556#ifdef HAVE_PPSAPI 557static void 558wwvb_control( 559 int unit, 560 const struct refclockstat *in_st, 561 struct refclockstat *out_st, 562 struct peer *peer 563 ) 564{ 565 register struct wwvbunit *up; 566 struct refclockproc *pp; 567 568 pp = peer->procptr; 569 up = pp->unitptr; 570 571 if (!(pp->sloppyclockflag & CLK_FLAG1)) { 572 if (!up->ppsapi_tried) 573 return; 574 up->ppsapi_tried = 0; 575 if (!up->ppsapi_lit) 576 return; 577 peer->flags &= ~FLAG_PPS; 578 peer->precision = PRECISION; 579 time_pps_destroy(up->atom.handle); 580 up->atom.handle = 0; 581 up->ppsapi_lit = 0; 582 return; 583 } 584 585 if (up->ppsapi_tried) 586 return; 587 /* 588 * Light up the PPSAPI interface. 589 */ 590 up->ppsapi_tried = 1; 591 if (refclock_ppsapi(pp->io.fd, &up->atom)) { 592 up->ppsapi_lit = 1; 593 return; 594 } 595 596 msyslog(LOG_WARNING, "%s flag1 1 but PPSAPI fails", 597 refnumtoa(&peer->srcadr)); 598} 599#endif /* HAVE_PPSAPI */ 600 601#else 602int refclock_wwvb_bs; 603#endif /* REFCLOCK */ 604