From: Pekka Helenius <fincer89@hotmail.com>
Date: Wed, 20 Jan 2021 23:20:31 +0300
Subject: Assume system clock is synced when time offset is in specific range limits (quick hotfix).


--- a/src/ntpd.c	2020-08-03 23:48:23.609231373 +0300
+++ b/src/ntpd.c	2021-01-20 23:00:53.946365898 +0200
@@ -566,9 +566,12 @@ ntpd_adjtime(double d)
 			log_warn("main process: time adjustment failed due to time error");
 	} else if (rc < 0) {
 		log_warn("main process: time adjustment failed");
-	} else if (!firstadj && tx.offset == offset) {
+    }
+	if (tx.offset > -(conf->synced_offset) || tx.offset < conf->synced_offset) {
 		synced = 1;
-	}
+	} else {
+        synced = 0;
+    }
 #else
 	struct timeval	tv, olddelta;
 	d_to_tv(d, &tv);
--- a/src/ntpd.h	2020-08-03 23:25:02.978705101 +0300
+++ b/src/ntpd.h	2021-01-20 23:09:58.945735647 +0200
@@ -76,6 +76,7 @@
 #define	SETTIME_TIMEOUT		100	/* max seconds to wait when settime == 1 */
 #define	LOG_NEGLIGIBLE_ADJTIME	32	/* negligible drift to not log (ms) */
 #define	LOG_NEGLIGIBLE_ADJFREQ	0.05	/* negligible rate to not log (ppm) */
+#define	SYNCED_OFFSET	100	/* Synced time offset (μs) */
 #define	FREQUENCY_SAMPLES	8	/* samples for est. of permanent drift */
 #define	MAX_FREQUENCY_ADJUST	128e-5	/* max correction per iteration */
 #define MAX_SEND_ERRORS		3	/* max send errors before reconnect */
@@ -313,6 +314,7 @@ struct ntpd_conf {
 	int						settime_timeout;
 
 	int						log_negligible_adjtime;
+	int						synced_offset;
 	double						log_negligible_adjfreq;
 
 	int						frequency_samples;
--- a/src/parse.y	2020-08-03 23:22:43.401482642 +0300
+++ b/src/parse.y	2021-01-20 23:08:20.789182596 +0200
@@ -119,6 +119,8 @@ typedef struct {
 %token	_LOG_NEGLIGIBLE_ADJTIME
 %token	_LOG_NEGLIGIBLE_ADJFREQ
 
+%token	_SYNCED_OFFSET
+
 %token	_FREQUENCY_SAMPLES
 %token	_MAX_FREQUENCY_ADJUST
 
@@ -515,6 +517,10 @@ main		: LISTEN ON address listen_opts	{
 			conf->log_negligible_adjfreq = $2.pos_decimal;
 		}
 
+		| _SYNCED_OFFSET pos_num {
+			conf->synced_offset = $2.pos_num;
+		}
+
 		| _FREQUENCY_SAMPLES pos_num {
 			conf->frequency_samples = $2.pos_num;
 		}
@@ -918,6 +924,7 @@ lookup(char *s)
 		{ "servers",		SERVERS,	"multiple" },
 		{ "settime_timeout",		_SETTIME_TIMEOUT,	"single" },
 		{ "stratum",		STRATUM,	"multiple" },
+		{ "synced_offset",		_SYNCED_OFFSET,	"single" },
 		{ "tries_auto_dnsfail",	_TRIES_AUTO_DNSFAIL,	"single" },
 		{ "trusted",		TRUSTED,	"multiple" },
 		{ "trustlevel_aggressive",		_TRUSTLEVEL_AGGRESSIVE,	"single" },
@@ -1293,6 +1300,9 @@ init_conf(struct ntpd_conf *conf)
 	/* negligible rate to not log (ppm) */
 	conf->log_negligible_adjfreq			= LOG_NEGLIGIBLE_ADJFREQ; // 0.05;
 
+	/* negligible drift to not log (ms) */
+	conf->synced_offset			= SYNCED_OFFSET; // 100;
+
 	/* samples for est. of permanent drift */
 	conf->frequency_samples			= FREQUENCY_SAMPLES; // 8;
 
@@ -1372,6 +1382,8 @@ print_conf(struct ntpd_conf *lconf)
 	fprintf(stdout, "Neglible drift time to not log: %d milliseconds\n", conf->log_negligible_adjtime);
 	fprintf(stdout, "Neglible frequency rate to not log: %f ppm\n",      conf->log_negligible_adjfreq);
 	fprintf(stdout, "\n");
+	fprintf(stdout, "Synced time offset threshold: %d microseconds\n", conf->synced_offset);
+	fprintf(stdout, "\n");
 	fprintf(stdout, "Frequency samples for estimation of permanent drift: %d\n", conf->frequency_samples);
 	fprintf(stdout, "Maximum frequency correction per iteration: %f\n",          conf->max_frequency_adjust);
 	fprintf(stdout, "\n");
--- a/src/ntpd.conf.5	2020-08-03 23:21:11.124672226 +0300
+++ b/src/ntpd.conf.5	2021-01-20 23:12:45.628871438 +0200
@@ -676,6 +676,14 @@ Negligible drift time to not log in mill
 32
 .El
 .Ed
+.It Ic synced_offset Ar microseconds
+Synced time offset threshold in microseconds.
+.Bd -literal -offset indent
+.Bl -tag -width "Default:" -compact
+.It Default:
+100
+.El
+.Ed
 .It Ic max_frequency_adjust Ar decimal
 Maximum allowed frequency correction per iteration.
 .Bd -literal -offset indent
--- a/ntpd.conf	2020-08-03 23:19:18.951338773 +0300
+++ b/ntpd.conf	2021-01-20 23:14:56.802048541 +0200
@@ -246,6 +246,12 @@ constraints from "https://www.duckduckgo
 #
 # log_negligible_adjtime      32
 
+# Synced time offset threshold in microseconds.
+# If our time adjustment value exceeds the threshold
+# we assume the clock is not synced anymore.
+#
+# synced_offset               100
+
 # Maximum allowed frequency correction per iteration.
 #
 # max_frequency_adjust        0.0128