refclock_arc.c

网络时间协议NTP 源码 版本v4.2.0b 该源码用于linux平台下

	   (pp->day < 1) || (pp->day > 31) ||
	   (month < 1) || (month > 12) ||
	   (pp->year < 0) || (pp->year > 99)) {
		/* Data out of range. */
		pp->lencode = 0;
		refclock_report(peer, CEVNT_BADREPLY);
		return;
	}


	if(peer->MODE == 0) { /* compatiblity to original version */
		int bst = flags;
		/* Check that BST/UTC bits are the complement of one another. */
		if(!(bst & 2) == !(bst & 4)) {
			pp->lencode = 0;
			refclock_report(peer, CEVNT_BADREPLY);
			return;
		}
	}
	if(status & 0x8) { msyslog(LOG_NOTICE, "ARCRON: battery low"); }

	/* Year-2000 alert! */
	/* Attempt to wrap 2-digit date into sensible window. */
	if(pp->year < YEAR_PIVOT) { pp->year += 100; }		/* Y2KFixes */
	pp->year += 1900;	/* use full four-digit year */	/* Y2KFixes */
	/*
	  Attempt to do the right thing by screaming that the code will
	  soon break when we get to the end of its useful life.  What a
	  hero I am...  PLEASE FIX LEAP-YEAR AND WRAP CODE IN 209X!
	*/
	if(pp->year >= YEAR_PIVOT+2000-2 ) {  			/* Y2KFixes */
		/*This should get attention B^> */
		msyslog(LOG_NOTICE,
		       "ARCRON: fix me!  EITHER YOUR DATE IS BADLY WRONG or else I will break soon!");
	}
#ifdef DEBUG
	if(debug) {
		printf("arc: n=%d %02d:%02d:%02d %02d/%02d/%04d %1d %1d\n",
		       n,
		       pp->hour, pp->minute, pp->second,
		       pp->day, month, pp->year, flags, status);
	}
#endif

	/*
	  The status value tested for is not strictly supported by the
	  clock spec since the value of bit 2 (0x4) is claimed to be
	  undefined for MSF, yet does seem to indicate if the last resync
	  was successful or not.
	*/
	pp->leap = LEAP_NOWARNING;
	status &= 0x7;
	if(status == 0x3) {
		if(status != up->status)
		{ msyslog(LOG_NOTICE, "ARCRON: signal acquired"); }
	} else {
		if(status != up->status) {
			msyslog(LOG_NOTICE, "ARCRON: signal lost");
			pp->leap = LEAP_NOTINSYNC; /* MSF clock is free-running. */
			up->status = status;
			pp->lencode = 0;
			refclock_report(peer, CEVNT_FAULT);
			return;
		}
	}
	up->status = status;

	if (peer->MODE == 0) { /* compatiblity to original version */
		int bst = flags;

		pp->day += moff[month - 1];

		if(isleap_4(pp->year) && month > 2) { pp->day++; }/* Y2KFixes */

		/* Convert to UTC if required */
		if(bst & 2) {
			pp->hour--;
			if (pp->hour < 0) {
				pp->hour = 23;
				pp->day--;
				/* If we try to wrap round the year
				 * (BST on 1st Jan), reject.*/
				if(pp->day < 0) {
					pp->lencode = 0;
					refclock_report(peer, CEVNT_BADTIME);
					return;
				}
			}
		}
	}

	if(peer->MODE > 0) {
		if(pp->sloppyclockflag & CLK_FLAG1) {
			struct tm  local;
		        struct tm *gmtp;
		        time_t     unixtime;

		        /*
		         * Convert to GMT for sites that distribute localtime.
			 * This means we have to do Y2K conversion on the
			 * 2-digit year; otherwise, we get the time wrong.
	        	 */
	   
			local.tm_year  = pp->year-1900;
	     	  	local.tm_mon   = month-1;
	      	  	local.tm_mday  = pp->day;
	        	local.tm_hour  = pp->hour;
	        	local.tm_min   = pp->minute;
	        	local.tm_sec   = pp->second;
	        	switch (peer->MODE) {
			    case 1:
				local.tm_isdst = (flags & 2);
				break;
			    case 2:
			        local.tm_isdst = (flags & 2);
				break;
			    case 3:
				switch (flags & 3) {
				    case 0: /* It is unclear exactly when the 
				    	       Arcron changes from DST->ST and 
					       ST->DST. Testing has shown this
					       to be irregular. For the time 
					       being, let the OS decide. */
				        local.tm_isdst = 0;
#ifdef DEBUG
					if (debug)
					    printf ("arc: DST = 00 (0)\n"); 
#endif
					break;
				    case 1: /* dst->st time */
				        local.tm_isdst = -1;
#ifdef DEBUG
					if (debug) 
					    printf ("arc: DST = 01 (1)\n"); 
#endif
					break;
				    case 2: /* st->dst time */
				        local.tm_isdst = -1;
#ifdef DEBUG
					if (debug) 
					    printf ("arc: DST = 10 (2)\n"); 
#endif
					break;
				    case 3: /* dst time */
				        local.tm_isdst = 1;
#ifdef DEBUG
					if (debug) 
					    printf ("arc: DST = 11 (3)\n"); 
#endif
					break;
				}
				break;
			    default:
				msyslog(LOG_NOTICE, "ARCRON: Invalid mode %d",
		      			peer->MODE);
				return;
				break;
			}
	        	unixtime = mktime (&local);
	        	if ((gmtp = gmtime (&unixtime)) == NULL)
	        	{
				pp->lencode = 0;
			        refclock_report (peer, CEVNT_FAULT);
			        return;
	        	}
			pp->year = gmtp->tm_year+1900;
	        	month = gmtp->tm_mon+1;
		    	pp->day = ymd2yd(pp->year,month,gmtp->tm_mday);
	       	 	/* pp->day = gmtp->tm_yday; */
	        	pp->hour = gmtp->tm_hour;
	        	pp->minute = gmtp->tm_min;
	        	pp->second = gmtp->tm_sec;
#ifdef DEBUG
	        	if (debug)
			{
				printf ("arc: time is %04d/%02d/%02d %02d:%02d:%02d UTC\n",
					pp->year,month,gmtp->tm_mday,pp->hour,pp->minute,
					pp->second);
			}
#endif
		} else 
		{
		    	/*
		     	* For more rational sites distributing UTC
		     	*/
		    	pp->day    = ymd2yd(pp->year,month,pp->day);
		}
	}

	if (peer->MODE == 0) { /* compatiblity to original version */
				/* If clock signal quality is 
				 * unknown, revert to default PRECISION...*/
		if(up->quality == QUALITY_UNKNOWN) { 
			peer->precision = PRECISION; 
		} else { /* ...else improve precision if flag3 is set... */
			peer->precision = ((pp->sloppyclockflag & CLK_FLAG3) ?
					   HIGHPRECISION : PRECISION);
		}
	} else {
		if ((status == 0x3) && (pp->sloppyclockflag & CLK_FLAG2)) {
			peer->precision = ((pp->sloppyclockflag & CLK_FLAG3) ?
					   HIGHPRECISION : PRECISION);
		} else if (up->quality == QUALITY_UNKNOWN) {
			peer->precision = PRECISION;
		} else {
			peer->precision = ((pp->sloppyclockflag & CLK_FLAG3) ?
					   HIGHPRECISION : PRECISION);
		}
	}

	/* Notice and log any change (eg from initial defaults) for flags. */
	if(up->saved_flags != pp->sloppyclockflag) {
#ifdef DEBUG
		msyslog(LOG_NOTICE, "ARCRON: flags enabled: %s%s%s%s",
		       ((pp->sloppyclockflag & CLK_FLAG1) ? "1" : "."),
		       ((pp->sloppyclockflag & CLK_FLAG2) ? "2" : "."),
		       ((pp->sloppyclockflag & CLK_FLAG3) ? "3" : "."),
		       ((pp->sloppyclockflag & CLK_FLAG4) ? "4" : "."));
		/* Note effects of flags changing... */
		if(debug) {
			printf("arc: PRECISION = %d.\n", peer->precision);
		}
#endif
		up->saved_flags = pp->sloppyclockflag;
	}

	/* Note time of last believable timestamp. */
	pp->lastrec = up->lastrec;

#ifdef ARCRON_LEAPSECOND_KEEN
	/* Find out if a leap-second might just have happened...
	   (ie is this the first hour of the first day of Jan or Jul?)
	*/
	if((pp->hour == 0) &&
	   (pp->day == 1) &&
	   ((month == 1) || (month == 7))) {
		if(possible_leap >= 0) {
			/* A leap may have happened, and no resync has started yet...*/
			possible_leap = 1;
		}
	} else {
		/* Definitely not leap-second territory... */
		possible_leap = 0;
	}
#endif

	if (!refclock_process(pp)) {
		pp->lencode = 0;
		refclock_report(peer, CEVNT_BADTIME);
		return;
	}
	record_clock_stats(&peer->srcadr, pp->a_lastcode);
	refclock_receive(peer);
}


/* request_time() sends a time request to the clock with given peer. */
/* This automatically reports a fault if necessary. */
/* No data should be sent after this until arc_poll() returns. */
static  void    request_time    P((int, struct peer *));
static void
request_time(
	int unit,
	struct peer *peer
	)
{
	struct refclockproc *pp = peer->procptr;
	register struct arcunit *up = (struct arcunit *)pp->unitptr;
#ifdef DEBUG
	if(debug) { printf("arc: unit %d: requesting time.\n", unit); }
#endif
	if (!send_slow(up, pp->io.fd, "o\r")) {
#ifdef DEBUG
		if (debug) {
			printf("arc: unit %d: problem sending", unit);
		}
#endif
		pp->lencode = 0;
		refclock_report(peer, CEVNT_FAULT);
		return;
	}
	pp->polls++;
}

/*
 * arc_poll - called by the transmit procedure
 */
static void
arc_poll(
	int unit,
	struct peer *peer
	)
{
	register struct arcunit *up;
	struct refclockproc *pp;
	int resync_needed;              /* Should we start a resync? */

	pp = peer->procptr;
	up = (struct arcunit *)pp->unitptr;
#if 0
	pp->lencode = 0;
	memset(pp->a_lastcode, 0, sizeof(pp->a_lastcode));
#endif

#if 0
	/* Flush input. */
	tcflush(pp->io.fd, TCIFLUSH);
#endif

	/* Resync if our next scheduled resync time is here or has passed. */
	resync_needed = ( !(pp->sloppyclockflag & CLK_FLAG2) &&
			  (up->next_resync <= current_time) );

#ifdef ARCRON_LEAPSECOND_KEEN
	/*
	  Try to catch a potential leap-second insertion or deletion quickly.

	  In addition to the normal NTP fun of clocks that don't report
	  leap-seconds spooking their hosts, this clock does not even
	  sample the radio sugnal the whole time, so may miss a
	  leap-second insertion or deletion for up to a whole sample
	  time.

	  To try to minimise this effect, if in the first few minutes of
	  the day immediately following a leap-second-insertion point
	  (ie in the first hour of the first day of the first and sixth
	  months), and if the last resync was in the previous day, and a
	  resync is not already in progress, resync the clock
	  immediately.

	*/
	if((possible_leap > 0) &&       /* Must be 00:XX 01/0{1,7}/XXXX. */
	   (!up->resyncing)) {          /* No resync in progress yet. */
		resync_needed = 1;
		possible_leap = -1;          /* Prevent multiple resyncs. */
		msyslog(LOG_NOTICE,"ARCRON: unit %d: checking for leap second",unit);
	}
#endif

	/* Do a resync if required... */
	if(resync_needed) {
		/* First, reset quality value to `unknown' so we can detect */
		/* when a quality message has been responded to by this     */
		/* being set to some other value.                           */
		up->quality = QUALITY_UNKNOWN;

		/* Note that we are resyncing... */
		up->resyncing = 1;

		/* Now actually send the resync command and an immediate poll. */
#ifdef DEBUG
		if(debug) { printf("arc: sending resync command (h\\r).\n"); }
#endif
		msyslog(LOG_NOTICE, "ARCRON: unit %d: sending resync command", unit);
		send_slow(up, pp->io.fd, "h\r");

		/* Schedule our next resync... */
		up->next_resync = current_time + DEFAULT_RESYNC_TIME;

		/* Drop through to request time if appropriate. */
	}

	/* If clock quality is too poor to trust, indicate a fault. */
	/* If quality is QUALITY_UNKNOWN and ARCRON_KEEN is defined,*/
	/* we'll cross our fingers and just hope that the thing     */
	/* synced so quickly we did not catch it---we'll            */
	/* double-check the clock is OK elsewhere.                  */
	if(
#ifdef ARCRON_KEEN
		(up->quality != QUALITY_UNKNOWN) &&
#else
		(up->quality == QUALITY_UNKNOWN) ||
#endif
		(up->quality < MIN_CLOCK_QUALITY_OK)) {
#ifdef DEBUG
		if(debug) {
			printf("arc: clock quality %d too poor.\n", up->quality);
		}
#endif
		pp->lencode = 0;
		refclock_report(peer, CEVNT_FAULT);
		return;
	}
	/* This is the normal case: request a timestamp. */
	request_time(unit, peer);
}

#else
int refclock_arc_bs;
#endif