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