From: Dave Hart <hart@ntp.org>
Date: Tue, 17 May 2011 23:17:51 +0000 (+0000)
Subject: Bug 1933 - WWVB/Spectracom driver timestamps LFs, not CRs
X-Git-Tag: NTP_4_2_7P169~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=389ef3fb89f18b59da69e685520dab3141112557;p=thirdparty%2Fntp.git

Bug 1933 - WWVB/Spectracom driver timestamps LFs, not CRs

bk: 4dd3021fc-hFvkEX2wp0QSoYil-BXg
---

diff --git a/ChangeLog b/ChangeLog
index b10ea7851..13dc235cf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,4 @@
+* [Bug 1933] WWVB/Spectracom driver timestamps LFs, not CRs.
 (4.2.7p168) 2011/05/16 Released by Harlan Stenn <stenn@ntp.org>
 * Convert receive buffer queue from doubly-linked list to FIFO.
 (4.2.7p167) 2011/05/14 Released by Harlan Stenn <stenn@ntp.org>
diff --git a/ntpd/refclock_wwvb.c b/ntpd/refclock_wwvb.c
index 39c75beb5..c9b3a34ae 100644
--- a/ntpd/refclock_wwvb.c
+++ b/ntpd/refclock_wwvb.c
@@ -54,7 +54,7 @@
  *	hh:mm:ss = hours, minutes, seconds
  *	i = synchronization flag (' ' = in synch, '?' = out of synch)
  *
- * The alarm condition is indicated by other than ' ' at a, which occurs
+ * The alarm condition is indicated by other than ' ' at i, which occurs
  * during initial synchronization and when received signal is lost for
  * about ten hours.
  *
@@ -69,7 +69,7 @@
  *	ddd = day of year
  *	hh:mm:ss.fff = hours, minutes, seconds, milliseconds
  *
- * The alarm condition is indicated by other than ' ' at a, which occurs
+ * The alarm condition is indicated by other than ' ' at i, which occurs
  * during initial synchronization and when received signal is lost for
  * about ten hours. The unlock condition is indicated by other than ' '
  * at q.
@@ -120,9 +120,8 @@
 #define	DESCRIPTION	"Spectracom WWVB/GPS Receiver" /* WRU */
 
 #define	LENWWVB0	22	/* format 0 timecode length */
-#define LENWWVB1	22	/* format 1 timecode length */
 #define	LENWWVB2	24	/* format 2 timecode length */
-#define LENWWVB3        29      /* format 3 timecode length */
+#define LENWWVB3	29	/* format 3 timecode length */
 #define MONLIN		15	/* number of monitoring lines */
 
 /*
@@ -136,7 +135,8 @@ struct wwvbunit {
 	int	tcount;		/* timecode sample counter */
 	int	pcount;		/* PPS sample counter */
 #endif /* HAVE_PPSAPI */
-	l_fp	laststamp;	/* last receive timestamp */
+	l_fp	laststamp;	/* last <CR> timestamp */
+	int	prev_eol_cr;	/* was last EOL <CR> (not <LF>)? */
 	u_char	lasthour;	/* last hour (for monitor) */
 	u_char	linect;		/* count ignored lines (for monitor */
 };
@@ -249,6 +249,7 @@ wwvb_receive(
 	struct recvbuf *rbufp
 	)
 {
+	const l_fp one_char_time = { { 0 }, { (u_int32)(FRAC / 960) } };
 	struct wwvbunit *up;
 	struct refclockproc *pp;
 	struct peer *peer;
@@ -280,13 +281,43 @@ wwvb_receive(
 	 * reading precision is only to the millisecond. Thus, unless
 	 * you have a PPS gadget and don't have to have the year, format
 	 * 0 provides the lowest jitter.
+	 * Save the timestamp of each <CR> in up->laststamp.  Lines with
+	 * no characters occur for every <LF>, and for some <CR>s when
+	 * format 0 is used. Format 0 starts and ends each cycle with a
+	 * <CR><LF> pair, format 2 starts each cycle with its only pair.
+	 * The preceding <CR> is the on-time character for both formats.
+	 * The timestamp provided with non-empty lines corresponds to
+	 * the <CR> following the timecode, which is ultimately not used
+	 * with format 0 and is used for the following timecode for
+	 * format 2.
 	 */
 	if (temp == 0) {
-		up->laststamp = trtmp;
+		if (up->prev_eol_cr) {
+			DPRINTF(2, ("wwvb: <LF> @ %s\n",
+				    prettydate(&trtmp)));
+		} else {
+			up->laststamp = trtmp;
+			DPRINTF(2, ("wwvb: <CR> @ %s\n", 
+				    prettydate(&trtmp)));
+		}
+		up->prev_eol_cr = !up->prev_eol_cr;
 		return;
 	}
 	pp->lencode = temp;
 	pp->lastrec = up->laststamp;
+	up->laststamp = trtmp;
+	up->prev_eol_cr = TRUE;
+	DPRINTF(2, ("wwvb: code @ %s\n"
+		    "       using %s minus one char\n",
+		    prettydate(&trtmp), prettydate(&pp->lastrec)));
+	if (L_ISZERO(&pp->lastrec))
+		return;
+
+	/*
+	 * The start of the <CR> is the on-time event, while our
+	 * timestamp reflects the end of that <CR> at best. Adjust.
+	 */
+	L_SUB(&pp->lastrec, &one_char_time);
 
 	/*
 	 * We get down to business, check the timecode format and decode
@@ -306,9 +337,11 @@ wwvb_receive(
 		if (sscanf(pp->a_lastcode,
 		    "%c %3d %2d:%2d:%2d%c%cTZ=%2d",
 		    &syncchar, &pp->day, &pp->hour, &pp->minute,
-		    &pp->second, &tmpchar, &dstchar, &tz) == 8)
+		    &pp->second, &tmpchar, &dstchar, &tz) == 8) {
 			pp->nsec = 0;
 			break;
+		}
+		goto bad_format;
 
 	case LENWWVB2:
 
@@ -318,14 +351,19 @@ wwvb_receive(
 		    "%c%c %2d %3d %2d:%2d:%2d.%3ld %c",
 		    &syncchar, &qualchar, &pp->year, &pp->day,
 		    &pp->hour, &pp->minute, &pp->second, &pp->nsec,
-		    &leapchar) == 9)
+		    &leapchar) == 9) {
 			pp->nsec *= 1000000;
 			break;
+		}
+		goto bad_format;
 
 	case LENWWVB3:
 
-	   	/*
+		/*
 		 * Timecode format 3: "0003I yyyymmdd hhmmss+0000SL#"
+		 * WARNING: Undocumented, and the on-time character # is
+		 * not yet handled correctly by this driver.  It may be
+		 * as simple as compensating for an additional 1/960 s.
 		 */
 		if (sscanf(pp->a_lastcode,
 		    "0003%c %4d%2d%2d %2d%2d%2d+0000%c%c",
@@ -336,8 +374,10 @@ wwvb_receive(
 			pp->nsec = 0;
 			break;
 		}
+		goto bad_format;
 
 	default:
+	bad_format:
 
 		/*
 		 * Unknown format: If dumping internal table, record