refclock_ulink.c

网络时间协议NTP 源码 版本v4.2.0b 该源码用于linux平台下

		    *   space  Space character (0x20)
		    *   HH     Hours 00-23
		    *   :      This is the REAL in sync indicator (: = insync)	
		    *   MM     Minutes 00-59
		    *   :      : = in sync ? = NOT in sync
		    *   SS     Seconds 00-59
		    *   L      Leap second flag. Changes from space (0x20)
		    *          to 'I' or 'D' during month preceding leap
		    *          second adjustment. (I)nsert or (D)elete
		    *   +5     UT1 correction (sign + digit ))
		    */

   		       if (sscanf(pp->a_lastcode, 
                          "%*2c %*2c%2c%*c%4d%*c%3d%*4c %2d%c%2d:%2d%c%*2c",
   		          char_quality, &pp->year, &pp->day, 
                          &pp->hour, &syncchar, &pp->minute, &pp->second, 
                          &leapchar) == 8) { 
   		
   			  if (char_quality[0] == '0') {
   				quality = 0;
   			  } else if (char_quality[0] == '0') {
   				quality = (char_quality[1] & 0x0f);
   			  } else  {
   				quality = 99;
   			  }

   		          if (leapchar == 'I' ) leapchar = '+';
   		          if (leapchar == 'D' ) leapchar = '-';

		          /*
		          #ifdef DEBUG
		          if (debug) {
		             printf("ulink: char_quality %c %c\n", 
                                    char_quality[0], char_quality[1]);
			     printf("ulink: quality %d\n", quality);
			     printf("ulink: syncchar %x\n", syncchar);
			     printf("ulink: leapchar %x\n", leapchar);
                          }
                          #endif
                          */

                       }
		
                    } 
                    if(siglchar == SIGLCHAR33x) {
                
		   /*
		    * We got a Model 33X decoder.
		    * Timecode format from January 29, 2001 datasheet is:
		    *   <CR><LF>S9+D 00 YYYY+DDDUTCS HH:MM:SSL+5
		    *   S      WWVB decoder sync indicator. S for in-sync(?)
		    *          or N for noisy signal.
		    *   9+     RF signal level in S-units, 0-9 followed by
		    *          a space (0x20). The space turns to '+' if the
		    *          level is over 9.
		    *   D      Data bit 0, 1, 2 (position mark), or
		    *          3 (unknown).
		    *   space  Space character (0x20)
		    *   00     Hours since last good WWVB frame sync. Will 
		    *          be 00-23 hrs, or '1d' to '7d'. Will be 'Lk'
                    *          if currently in sync. 
		    *   space  Space character (0x20)
		    *   YYYY   Current year, 1990-2089
		    *   +      Leap year indicator. '+' if a leap year,
		    *          a space (0x20) if not.
		    *   DDD    Day of year, 001 - 366.
		    *   UTC    Timezone (always 'UTC').
		    *   S      Daylight savings indicator
		    *             S - standard time (STD) in effect
		    *             O - during STD to DST day 0000-2400
		    *             D - daylight savings time (DST) in effect
		    *             I - during DST to STD day 0000-2400
		    *   space  Space character (0x20)
		    *   HH     Hours 00-23
		    *   :      This is the REAL in sync indicator (: = insync)	
		    *   MM     Minutes 00-59
		    *   :      : = in sync ? = NOT in sync
		    *   SS     Seconds 00-59
		    *   L      Leap second flag. Changes from space (0x20)
		    *          to '+' or '-' during month preceding leap
		    *          second adjustment.
		    *   +5     UT1 correction (sign + digit ))
		    */

		       if (sscanf(pp->a_lastcode, 
                           "%*4c %2c %4d%*c%3d%*4c %2d%c%2d:%2d%c%*2c",
		           char_quality, &pp->year, &pp->day, 
                           &pp->hour, &syncchar, &pp->minute, &pp->second, 
                           &leapchar) == 8) { 
		
			   if (char_quality[0] == 'L') {
				quality = 0;
			   } else if (char_quality[0] == '0') {
				quality = (char_quality[1] & 0x0f);
			   } else  {
				quality = 99;
		           }
	
                           /*
                           #ifdef DEBUG
         		   if (debug) {
         			printf("ulink: char_quality %c %c\n", 
                                        char_quality[0], char_quality[1]);
         			printf("ulink: quality %d\n", quality);
         			printf("ulink: syncchar %x\n", syncchar);
         			printf("ulink: leapchar %x\n", leapchar);
                           }
                           #endif
                           */

		        }
                    }
		    break;
		}

		case LEN320:

	        /*
		 * Model 320 Decoder
		 * The timecode format is:
		 *
		 *  <cr><lf>SQRYYYYDDD+HH:MM:SS.mmLT<cr>
		 *
		 * where:
		 *
		 * S = 'S' -- sync'd in last hour,
		 *     '0'-'9' - hours x 10 since last update,
		 *     '?' -- not in sync
		 * Q = Number of correlating time-frames, from 0 to 5
		 * R = 'R' -- reception in progress,
		 *     'N' -- Noisy reception,
		 *     ' ' -- standby mode
		 * YYYY = year from 1990 to 2089
		 * DDD = current day from 1 to 366
		 * + = '+' if current year is a leap year, else ' '
		 * HH = UTC hour 0 to 23
		 * MM = Minutes of current hour from 0 to 59
		 * SS = Seconds of current minute from 0 to 59
		 * mm = 10's milliseconds of the current second from 00 to 99
		 * L  = Leap second pending at end of month
		 *     'I' = insert, 'D'= delete
		 * T  = DST <-> STD transition indicators
		 *
        	 */

		if (sscanf(pp->a_lastcode, "%c%1d%c%4d%3d%*c%2d:%2d:%2d.%2ld%c",
	               &syncchar, &quality, &modechar, &pp->year, &pp->day,
        	       &pp->hour, &pp->minute, &pp->second,
			&pp->nsec, &leapchar) == 10) {
		pp->nsec *= 10000000; /* M320 returns 10's of msecs */
		if (leapchar == 'I' ) leapchar = '+';
		if (leapchar == 'D' ) leapchar = '-';
		if (syncchar != '?' ) syncchar = ':';

 		break;
		}

		default:
		refclock_report(peer, CEVNT_BADREPLY);
		return;
	}

	/*
	 * Decode quality indicator
	 * For the 325 & 33x series, the lower the number the "better" 
	 * the time is. I used the dispersion as the measure of time 
	 * quality. The quality indicator in the 320 is the number of 
	 * correlating time frames (the more the better)
	 */

	/* 
	 * The spec sheet for the 325 & 33x series states the clock will
	 * maintain +/-0.002 seconds accuracy when locked to WWVB. This 
	 * is indicated by 'Lk' in the quality portion of the incoming 
	 * string. When not in lock, a drift of +/-0.015 seconds should 
	 * be allowed for.
	 * With the quality indicator decoding scheme above, the 'Lk' 
	 * condition will produce a quality value of 0. If the quality 
	 * indicator starts with '0' then the second character is the 
	 * number of hours since we were last locked. If the first 
	 * character is anything other than 'L' or '0' then we have been 
	 * out of lock for more than 9 hours so we assume the worst and 
	 * force a quality value that selects the 'default' maximum 
	 * dispersion. The dispersion values below are what came with the
	 * driver. They're not unreasonable so they've not been changed.
	 */

	if (pp->lencode == LEN33X) {
		switch (quality) {
			case 0 :
				pp->disp=.002;
				break;
			case 1 :
				pp->disp=.02;
				break;
			case 2 :
				pp->disp=.04;
				break;
			case 3 :
				pp->disp=.08;
				break;
			default:
				pp->disp=MAXDISPERSE;
				break;
		}
	} else {
		switch (quality) {
			case 5 :
				pp->disp=.002;
				break;
			case 4 :
				pp->disp=.02;
				break;
			case 3 :
				pp->disp=.04;
				break;
			case 2 :
				pp->disp=.08;
				break;
			case 1 :
				pp->disp=.16;
				break;
			default:
				pp->disp=MAXDISPERSE;
				break;
		}

	}

	/*
	 * Decode synchronization, and leap characters. If
	 * unsynchronized, set the leap bits accordingly and exit.
	 * Otherwise, set the leap bits according to the leap character.
	 */

	if (syncchar != ':')
		pp->leap = LEAP_NOTINSYNC;
	else if (leapchar == '+')
		pp->leap = LEAP_ADDSECOND;
	else if (leapchar == '-')
		pp->leap = LEAP_DELSECOND;
	else
		pp->leap = LEAP_NOWARNING;

	/*
	 * Process the new sample in the median filter and determine the
	 * timecode timestamp.
	 */
	if (!refclock_process(pp)) {
		refclock_report(peer, CEVNT_BADTIME);
	}

}

/*
 * ulink_poll - called by the transmit procedure
 */

static void
ulink_poll(
	int unit,
	struct peer *peer
	)
{
        struct refclockproc *pp;
        char pollchar;

        pp = peer->procptr;
        pollchar = 'T';
	if (pp->sloppyclockflag & CLK_FLAG1) {
	        if (write(pp->io.fd, &pollchar, 1) != 1)
        	        refclock_report(peer, CEVNT_FAULT);
        	else
      	            pp->polls++;
	}
	else
      	            pp->polls++;

        if (peer->burst > 0)
                return;
        if (pp->coderecv == pp->codeproc) {
                refclock_report(peer, CEVNT_TIMEOUT);
                return;
        }
        pp->lastref = pp->lastrec;
	refclock_receive(peer);
	record_clock_stats(&peer->srcadr, pp->a_lastcode);
        peer->burst = NSTAGE;

}

#else
int refclock_ulink_bs;
#endif /* REFCLOCK */