If constraints are configured but do not work for whatever reason ntpd

does not work. Make that more clear in the log and ntpdctl -s status.
report by and ok benno@

src/usr.sbin/ntpd/constraint.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: constraint.c,v 1.48 2019/07/16 14:15:40 otto Exp $	*/
+/*	$OpenBSD: constraint.c,v 1.49 2020/02/12 19:14:56 otto Exp $	*/
 
 /*
  * Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
@@ -695,8 +695,9 @@ constraint_msg_result(u_int32_t id, u_int8_t *data, size_t len)
 void
 constraint_msg_close(u_int32_t id, u_int8_t *data, size_t len)
 {
-	struct constraint	*cstr;
-	int			 fail;
+	struct constraint	*cstr, *tmp;
+	int			 fail, cnt;
+	static int		 total_fails;
 
 	if ((cstr = constraint_byid(id)) == NULL) {
 		log_warnx("IMSG_CONSTRAINT_CLOSE with invalid constraint id");
@@ -715,6 +716,15 @@ constraint_msg_close(u_int32_t id, u_int8_t *data, size_t len)
 		    " received in time, next query %ds",
 		    log_sockaddr((struct sockaddr *)
 		    &cstr->addr->ss), CONSTRAINT_SCAN_INTERVAL);
+		
+		cnt = 0;
+		TAILQ_FOREACH(tmp, &conf->constraints, entry)
+			cnt++;
+		if (cnt > 0 && ++total_fails >= cnt &&
+		    conf->constraint_median == 0) {
+			log_warnx("constrainst configured but none available");
+			total_fails = 0;
+		}
 	}
 
 	if (fail || cstr->state < STATE_QUERY_SENT) {

src/usr.sbin/ntpd/control.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: control.c,v 1.17 2019/07/10 05:53:37 otto Exp $ */
+/*	$OpenBSD: control.c,v 1.18 2020/02/12 19:14:56 otto Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -329,6 +329,7 @@ build_show_status(struct ctl_show_status *cs)
 	cs->synced = conf->status.synced;
 	cs->stratum = conf->status.stratum;
 	cs->clock_offset = getoffset() * 1000.0;
+	cs->constraints = !TAILQ_EMPTY(&conf->constraints);
 	cs->constraint_median = conf->constraint_median;
 	cs->constraint_last = conf->constraint_last;
 	cs->constraint_errors = conf->constraint_errors;

src/usr.sbin/ntpd/ntp.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntp.c,v 1.162 2019/11/11 06:32:52 otto Exp $ */
+/*	$OpenBSD: ntp.c,v 1.163 2020/02/12 19:14:56 otto Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -228,7 +228,7 @@ ntp_main(struct ntpd_conf *nconf, struct passwd *pw, int argc, char **argv)
 
 		memset(pfd, 0, sizeof(*pfd) * pfd_elms);
 		memset(idx2peer, 0, sizeof(*idx2peer) * idx2peer_elms);
-		nextaction = getmonotime() + 3600;
+		nextaction = getmonotime() + 900;
 		pfd[PFD_PIPE_MAIN].fd = ibuf_main->fd;
 		pfd[PFD_PIPE_MAIN].events = POLLIN;
 		pfd[PFD_PIPE_DNS].fd = ibuf_dns->fd;

src/usr.sbin/ntpd/ntpd.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntpd.c,v 1.128 2019/11/11 06:32:52 otto Exp $ */
+/*	$OpenBSD: ntpd.c,v 1.129 2020/02/12 19:14:56 otto Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -810,7 +810,8 @@ show_status_msg(struct imsg *imsg)
 			printf(" (%d errors)",
 			    cstatus->constraint_errors);
 		printf(", ");
-	}
+	} else if (cstatus->constraints)
+		printf("constraints configured but none available, ");
 
 	if (cstatus->peercnt + cstatus->sensorcnt == 0)
 		printf("no peers and no sensors configured\n");

src/usr.sbin/ntpd/ntpd.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntpd.h,v 1.148 2019/11/11 06:32:52 otto Exp $ */
+/*	$OpenBSD: ntpd.h,v 1.149 2020/02/12 19:14:56 otto Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -254,16 +254,17 @@ struct ntpd_conf {
 };
 
 struct ctl_show_status {
+	time_t		 constraint_median;
+	time_t		 constraint_last;
+	double		 clock_offset;
 	u_int		 peercnt;
 	u_int		 sensorcnt;
 	u_int		 valid_peers;
 	u_int		 valid_sensors;
+	u_int		 constraint_errors;
 	u_int8_t	 synced;
 	u_int8_t	 stratum;
-	double		 clock_offset;
-	time_t		 constraint_median;
-	time_t		 constraint_last;
-	u_int		 constraint_errors;
+	u_int8_t	 constraints;
 };
 
 struct ctl_show_peer {