/* * refclock_irig - clock driver for the IRIG audio decoder */ #ifdef HAVE_CONFIG_H #include #endif #if defined(REFCLOCK) && defined(IRIG) #include #include #include #include #include "ntpd.h" #include "ntp_io.h" #include "ntp_refclock.h" #include "ntp_unixtime.h" #include #include "ntp_stdlib.h" /* * This driver supports the IRIG audio decoder. This clever gadget uses * a modified BSD audio driver for the Sun SPARCstation which provides * a timestamp, raw binary timecode, status byte and decoded ASCII * timecode. The data are represented in the structure in the * sys/bsd_audioirig.h header file: * * struct irig_time { * struct timeval stamp; timestamp * u_char bits[13]; 100 IRIG data bits * u_char status; status byte * char time[14]; time string (null terminated) * * where stamp represents a timestamp at the zero crossing of the index * marker at the second's epoch, bits is a 13-octet, zero-padded binary- * coded string representing code elements 1 through 100 in the IRIG-B * code format, and status is a status bute, The decoded timestamp is a * 13-octet, null-terminated ASCII string "ddd hh:mm:ss*", where ddd is * the day of year, hh:mm:ss the time of day and * is a status * indicator, with " " indicating valid time and "?" indicating * something wrong. * * The timestamp is in Unix timeval format, consisting of two 32-bit * words, the first of which is the seconds since 1970 and the second is * the fraction of the second in microseconds. The status byte is zero * if (a) the input signal is within amplitude tolerances, (b) the raw * binary timecode contains only valid code elements, (c) 11 position * identifiers have been found at the expected element positions, (d) * the clock status byte contained in the timecode is valid, and (e) a * time determination has been made since the last read() system call. * * The 100 elements of the IRIG-B timecode are numbered from 0 through * 99. Position identifiers occur at elements 0, 9, 19 and every ten * thereafter to 99. The control function (CF) elements begin at element * 50 (CF 1) and extend to element 78 (CF 27). The straight-binary- * seconds (SBS) field, which encodes the seconds of the UTC day, begins * at element 80 (CF 28) and extends to element 97 (CF 44). The encoding * of elements 50 (CF 1) through 78 (CF 27) is device dependent. This * driver presently does not use the CF elements. * * Where feasible, the interface should be operated with signature * control, so that, if the IRIG signal is lost or malformed, the * interface produces an unmodulated signal, rather than possibly random * digits. The driver will declare "unsynchronized" in this case. * * Spectracom Netclock/2 WWVB Synchronized Clock * * Element CF Function * ------------------------------------- * 55 6 time sync status * 60-63 10-13 bcd year units * 65-68 15-18 bcd year tens * */ /* * IRIG interface definitions */ #define DEVICE "/dev/irig%d" /* device name and unit */ #define PRECISION (-13) /* precision assumed (100 us) */ #define REFID "IRIG" /* reference ID */ #define DESCRIPTION "IRIG Audio Decoder" /* WRU */ #define NSAMPLES 3 /* stages of median filter */ #define IRIG_FORMAT 1 /* IRIG timestamp format */ /* * Imported from ntp_timer module */ extern u_long current_time; /* current time (s) */ /* * Imported from ntpd module */ extern int debug; /* global debug flag */ /* * Function prototypes */ static int irig_start P((int, struct peer *)); static void irig_shutdown P((int, struct peer *)); static void irig_poll P((int, struct peer *)); /* * Transfer vector */ struct refclock refclock_irig = { irig_start, /* start up driver */ irig_shutdown, /* shut down driver */ irig_poll, /* transmit poll message */ noentry, /* not used (old irig_control) */ noentry, /* initialize driver (not used) */ noentry, /* not used (old irig_buginfo) */ NOFLAGS /* not used */ }; /* * irig_start - open the device and initialize data for processing */ static int irig_start(unit, peer) int unit; struct peer *peer; { register struct refclockproc *pp; char device[20]; int fd; int format = IRIG_FORMAT; /* * Open audio device and set format */ (void)sprintf(device, DEVICE, unit); fd = open(device, O_RDONLY | O_NDELAY, 0777); if (fd == -1) { msyslog(LOG_ERR, "irig_start: open of %s: %m", device); return (0); } if (ioctl(fd, AUDIO_IRIG_OPEN, 0) < 0) { msyslog(LOG_ERR, "irig_start: AUDIO_IRIG_OPEN %m"); close(fd); return (0); } if (ioctl(fd, AUDIO_IRIG_SETFORMAT, (char *)&format) < 0) { msyslog(LOG_ERR, "irig_start: AUDIO_IRIG_SETFORMAT %m", DEVICE); close(fd); return (0); } pp = peer->procptr; pp->io.clock_recv = noentry; pp->io.srcclock = (caddr_t)peer; pp->io.datalen = 0; pp->io.fd = fd; /* * Initialize miscellaneous variables */ peer->precision = PRECISION; pp->clockdesc = DESCRIPTION; memcpy((char *)&pp->refid, REFID, 4); return (1); } /* * irig_shutdown - shut down the clock */ static void irig_shutdown(unit, peer) int unit; struct peer *peer; { struct refclockproc *pp; pp = peer->procptr; io_closeclock(&pp->io); } /* * irig_poll - called by the transmit procedure */ static void irig_poll(unit, peer) int unit; struct peer *peer; { struct refclockproc *pp; struct irig_time buf; char *cp, *dp; u_char *dpt; int i; pp = peer->procptr; if (read(pp->io.fd, (char *) &buf, sizeof(buf)) != sizeof(buf)) { refclock_report(peer, CEVNT_FAULT); return; } pp->polls++; #ifdef DEBUG if (debug) { dpt = (u_char *)&buf; printf("irig: "); for (i = 0; i < sizeof(buf); i++) printf("%02x", *dpt++); printf("\n"); } #endif buf.stamp.tv_sec += JAN_1970; TVTOTS(&buf.stamp, &pp->lastrec); cp = buf.time; dp = pp->a_lastcode; for (i = 0; i < sizeof(buf.time); i++) *dp++ = *cp++; *--dp = '\0'; pp->lencode = dp - pp->a_lastcode; #ifdef DEBUG if (debug) printf("irig: time %s timecode %d %s\n", ulfptoa(&pp->lastrec, 6), pp->lencode, pp->a_lastcode); #endif record_clock_stats(&peer->srcadr, pp->a_lastcode); /* * Get IRIG time and convert to timestamp format */ if (sscanf(pp->a_lastcode, "%3d %2d:%2d:%2d", &pp->day, &pp->hour, &pp->minute, &pp->second) != 4) { refclock_report(peer, CEVNT_BADREPLY); return; } if (pp->a_lastcode[12] != ' ') { pp->leap = LEAP_NOTINSYNC; } else { pp->leap = 0; pp->lasttime = current_time; } /* * Process the new sample in the median filter and determine the * reference clock offset and dispersion. We use lastrec as both * the reference time and receive time in order to avoid being * cute, like setting the reference time later than the receive * time, which may cause a paranoid protocol module to chuck out * the data. */ if (!refclock_process(pp, NSAMPLES, NSAMPLES)) { refclock_report(peer, CEVNT_BADTIME); return; } refclock_receive(peer, &pp->offset, 0, pp->dispersion, &pp->lastrec, &pp->lastrec, pp->leap); } #else /* not (REFCLOCK && IRIG) */ int refclock_irig_bs; #endif /* not (REFCLOCK && IRIG) */