use a little state engine to keep track of delayed dns lookups and such,

eases things
tested by Jason Ackley <jason@ackley.net> Matthias Kilian
<kili@outback.escape.de> Stephen Marley <stephen@marley.org.uk> sturm@
theo ok

src/usr.sbin/ntpd/client.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: client.c,v 1.60 2005/04/19 11:08:41 henning Exp $ */
+/*	$OpenBSD: client.c,v 1.61 2005/06/19 16:42:57 henning Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -71,11 +71,13 @@ client_addr_init(struct ntp_peer *p)
 			sa_in = (struct sockaddr_in *)&h->ss;
 			if (ntohs(sa_in->sin_port) == 0)
 				sa_in->sin_port = htons(123);
+			p->state = STATE_DNS_DONE;
 			break;
 		case AF_INET6:
 			sa_in6 = (struct sockaddr_in6 *)&h->ss;
 			if (ntohs(sa_in6->sin6_port) == 0)
 				sa_in6->sin6_port = htons(123);
+			p->state = STATE_DNS_DONE;
 			break;
 		default:
 			fatal("king bula sez: wrong AF in client_addr_init");
@@ -97,6 +99,7 @@ client_nextaddr(struct ntp_peer *p)
 
 	if (p->addr_head.a == NULL) {
 		priv_host_dns(p->addr_head.name, p->id);
+		p->state = STATE_DNS_INPROGRESS;
 		return (-1);
 	}
 
@@ -119,6 +122,9 @@ client_query(struct ntp_peer *p)
 		return (0);
 	}
 
+	if (p->state < STATE_DNS_DONE || p->addr == NULL)
+		return (-1);
+
 	if (p->query->fd == -1) {
 		struct sockaddr *sa = (struct sockaddr *)&p->addr->ss;
 

src/usr.sbin/ntpd/ntp.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntp.c,v 1.60 2005/05/26 09:13:06 dtucker Exp $ */
+/*	$OpenBSD: ntp.c,v 1.61 2005/06/19 16:42:57 henning Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -194,13 +194,14 @@ ntp_main(int pipe_prnt[2], struct ntpd_conf *nconf)
 		idx_peers = i;
 		sent_cnt = trial_cnt = 0;
 		TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
-			if (p->next > 0 && p->next < nextaction)
-				nextaction = p->next;
 			if (p->next > 0 && p->next <= time(NULL)) {
-				trial_cnt++;
+				if (p->state > STATE_DNS_INPROGRESS)
+					trial_cnt++;
 				if (client_query(p) == 0)
 					sent_cnt++;
 			}
+			if (p->next > 0 && p->next < nextaction)
+				nextaction = p->next;
 
 			if (p->deadline > 0 && p->deadline < nextaction)
 				nextaction = p->deadline;
@@ -326,7 +327,13 @@ ntp_dispatch_imsg(void)
 				log_warnx("IMSG_HOST_DNS but addr != NULL!");
 				break;
 			}
+
 			dlen = imsg.hdr.len - IMSG_HEADER_SIZE;
+			if (dlen == 0) {	/* no data -> temp error */
+				peer->state = STATE_DNS_TEMPFAIL;
+				break;
+			}
+
 			p = (u_char *)imsg.data;
 			while (dlen >= sizeof(struct sockaddr_storage)) {
 				if ((h = calloc(1, sizeof(struct ntp_addr))) ==
@@ -341,11 +348,13 @@ ntp_dispatch_imsg(void)
 					npeer->addr = h;
 					npeer->addr_head.a = h;
 					client_peer_init(npeer);
+					npeer->state = STATE_DNS_DONE;
 					peer_add(npeer);
 				} else {
 					h->next = peer->addr;
 					peer->addr = h;
 					peer->addr_head.a = peer->addr;
+					peer->state = STATE_DNS_DONE;
 				}
 			}
 			if (dlen != 0)

src/usr.sbin/ntpd/ntpd.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntpd.c,v 1.36 2005/05/26 09:13:06 dtucker Exp $ */
+/*	$OpenBSD: ntpd.c,v 1.37 2005/06/19 16:42:57 henning Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -289,17 +289,17 @@ dispatch_imsg(struct ntpd_conf *conf)
 			if (name[imsg.hdr.len] != '\0' ||
 			    strlen(name) != imsg.hdr.len)
 				fatalx("invalid IMSG_HOST_DNS received");
-			if ((cnt = host_dns(name, &hn)) > 0) {
-				buf = imsg_create(ibuf, IMSG_HOST_DNS,
-				    imsg.hdr.peerid, 0,
-				    cnt * sizeof(struct sockaddr_storage));
-				if (buf == NULL)
-					break;
-				for (h = hn; h != NULL; h = h->next) {
+			cnt = host_dns(name, &hn);
+			buf = imsg_create(ibuf, IMSG_HOST_DNS,
+			    imsg.hdr.peerid, 0,
+			    cnt * sizeof(struct sockaddr_storage));
+			if (buf == NULL)
+				break;
+			if (cnt > 0)
+				for (h = hn; h != NULL; h = h->next)
 					imsg_add(buf, &h->ss, sizeof(h->ss));
-				}
-				imsg_close(ibuf, buf);
-			}
+
+			imsg_close(ibuf, buf);
 			break;
 		default:
 			break;

src/usr.sbin/ntpd/ntpd.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntpd.h,v 1.55 2005/04/26 15:18:22 henning Exp $ */
+/*	$OpenBSD: ntpd.h,v 1.56 2005/06/19 16:42:57 henning Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -59,6 +59,9 @@
 
 enum client_state {
 	STATE_NONE,
+	STATE_DNS_INPROGRESS,
+	STATE_DNS_TEMPFAIL,
+	STATE_DNS_DONE,
 	STATE_QUERY_SENT,
 	STATE_REPLY_RECEIVED
 };

src/usr.sbin/ntpd/parse.y

@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.24 2004/11/25 06:27:41 henning Exp $ */
+/*	$OpenBSD: parse.y,v 1.25 2005/06/19 16:42:57 henning Exp $ */
 
 /*
  * Copyright (c) 2002, 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -134,6 +134,8 @@ conf_main	: LISTEN ON address	{
 				p->addr_head.name = strdup($2->name);
 				if (p->addr_head.name == NULL)
 					fatal(NULL);
+				if (p->addr != NULL)
+					p->state = STATE_DNS_DONE;
 				TAILQ_INSERT_TAIL(&conf->ntp_peers, p, entry);
 
 				h = next;
@@ -168,6 +170,8 @@ conf_main	: LISTEN ON address	{
 			p->addr_head.name = strdup($2->name);
 			if (p->addr_head.name == NULL)
 				fatal(NULL);
+			if (p->addr != NULL)
+				p->state = STATE_DNS_DONE;
 			TAILQ_INSERT_TAIL(&conf->ntp_peers, p, entry);
 			free($2->name);
 			free($2);