[ntpsec commit] Forward-port Frank Kardel's fix for NTP Classic [Bug 2836] .

[Eric S. Raymond]

Module:    ntpsec
Branch:    master
Commit:    fc03342073a695d7425c1c2ee36c87af6c61dfc9
Changeset: http://git.ntpsec.org/ntpsec/commit/?id=fc03342073a695d7425c1c2ee36c87af6c61dfc9

Author:    Eric S. Raymond <esr at thyrsus.com>
Date:      Thu Oct 22 10:07:55 2015 -0400

Forward-port Frank Kardel's fix for NTP Classic [Bug 2836].

---

 NEWS                  | 5 +++++
 libparse/clk_rawdcf.c | 6 ++++--
 libparse/parse.c      | 4 ++--
 ntpd/refclock_parse.c | 2 ++
 4 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/NEWS b/NEWS
index d1792e1..e1a8e1a 100644
--- a/NEWS
+++ b/NEWS
@@ -6,4 +6,9 @@ Much of the traditional function of a news file is now better addressed
 by browsing the comments in the revision history.  This file will focus
 on user-visible changes.
 
+== Forward-ported bugfixes from NTP Classic ==
+
+* [Bug 2836] DFC77 patches from Frank Kardel to make decoding more
+  robust, and require 2 consecutive timestamps to be consistent.
+
 // end
diff --git a/libparse/clk_rawdcf.c b/libparse/clk_rawdcf.c
index 4e1bf8c..b738243 100644
--- a/libparse/clk_rawdcf.c
+++ b/libparse/clk_rawdcf.c
@@ -196,7 +196,7 @@ convert_rawdcf(
 	if (size < 57)
 	{
 		msyslog(LOG_ERR, "parse: convert_rawdcf: INCOMPLETE DATA - time code only has %d bits", size);
-		return CVT_NONE;
+		return CVT_FAIL|CVT_BADFMT;
 	}
 
 	for (i = 0; i < size; i++)
@@ -454,11 +454,13 @@ cvt_rawdcf(
 			{
 				if ((newtime - t->tcode) == 60) /* guard against multi bit errors */
 				{
+					parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: minute delta check OK\n"));
 					clock_time->utctime = newtime;
 				}
 				else
 				{
-					rtc = CVT_FAIL|CVT_BADTIME;
+					parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: minute delta check FAIL - ignore timestamp\n"));
+					rtc = CVT_SKIP;
 				}
 				t->tcode            = newtime;
 			}
diff --git a/libparse/parse.c b/libparse/parse.c
index 5776c1b..8610187 100644
--- a/libparse/parse.c
+++ b/libparse/parse.c
@@ -635,14 +635,14 @@ timepacket(
 	{
 	case CVT_FAIL:
 		parseio->parse_badformat++;
-		break;
+		return cvtrtc;
 
 	case CVT_NONE:
 		/*
 		 * too bad - pretend bad format
 		 */
 		parseio->parse_badformat++;
-		break;
+		return CVT_NONE;
 
 	case CVT_OK:
 		break;
diff --git a/ntpd/refclock_parse.c b/ntpd/refclock_parse.c
index 927819d..4d7eb8b 100644
--- a/ntpd/refclock_parse.c
+++ b/ntpd/refclock_parse.c
@@ -3217,6 +3217,8 @@ parse_process(
 					msyslog(LOG_WARNING, "PARSE receiver #%d: FAILED TIMECODE: \"%s\" (check receiver configuration / wiring)",
 						CLK_UNIT(parse->peer), mkascii(buffer, sizeof buffer, tmpctl.parsegettc.parse_buffer, (unsigned)(tmpctl.parsegettc.parse_count - 1)));
 			}
+			/* copy status to show only changes in case of failures */
+			parse->timedata.parse_status = parsetime->parse_status;
 		}
 	}