Reconnect a client socket after three consecutive send failures.

This allows recovery after an IP address change (e.g. on dialup links).
Also move the update of "nextaction" timeout below the deadline check.
OK henning@

src/usr.sbin/ntpd/client.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: client.c,v 1.78 2007/12/27 01:46:50 stevesk Exp $ */
+/*	$OpenBSD: client.c,v 1.79 2008/01/28 11:45:59 mpf Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -54,6 +54,7 @@ client_peer_init(struct ntp_peer *p)
 	p->shift = 0;
 	p->trustlevel = TRUSTLEVEL_PATHETIC;
 	p->lasterror = 0;
+	p->senderrors = 0;
 
 	return (client_addr_init(p));
 }
@@ -172,11 +173,13 @@ client_query(struct ntp_peer *p)
 
 	if (ntp_sendmsg(p->query->fd, NULL, &p->query->msg,
 	    NTP_MSGSIZE_NOAUTH, 0) == -1) {
+		p->senderrors++;
 		set_next(p, INTERVAL_QUERY_PATHETIC);
 		p->trustlevel = TRUSTLEVEL_PATHETIC;
 		return (-1);
 	}
 
+	p->senderrors = 0;
 	p->state = STATE_QUERY_SENT;
 	set_deadline(p, QUERYTIME_MAX);
 

src/usr.sbin/ntpd/ntp.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntp.c,v 1.102 2007/12/27 01:46:50 stevesk Exp $ */
+/*	$OpenBSD: ntp.c,v 1.103 2008/01/28 11:45:59 mpf Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -229,11 +229,6 @@ ntp_main(int pipe_prnt[2], struct ntpd_conf *nconf, struct passwd *pw)
 				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;
 			if (p->deadline > 0 && p->deadline <= getmonotime()) {
 				timeout = error_interval();
 				log_debug("no reply from %s received in time, "
@@ -247,6 +242,19 @@ ntp_main(int pipe_prnt[2], struct ntpd_conf *nconf, struct passwd *pw)
 				client_nextaddr(p);
 				set_next(p, timeout);
 			}
+			if (p->senderrors > MAX_SEND_ERRORS) {
+				log_debug("failed to send query to %s, "
+				    "next query %ds", log_sockaddr(
+				    (struct sockaddr *)&p->addr->ss),
+				    INTERVAL_QUERY_PATHETIC);
+				p->senderrors = 0;
+				client_nextaddr(p);
+				set_next(p, INTERVAL_QUERY_PATHETIC);
+			}
+			if (p->next > 0 && p->next < nextaction)
+				nextaction = p->next;
+			if (p->deadline > 0 && p->deadline < nextaction)
+				nextaction = p->deadline;
 
 			if (p->state == STATE_QUERY_SENT &&
 			    p->query->fd != -1) {

src/usr.sbin/ntpd/ntpd.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ntpd.h,v 1.90 2007/12/23 18:39:50 stevesk Exp $ */
+/*	$OpenBSD: ntpd.h,v 1.91 2008/01/28 11:45:59 mpf Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -60,6 +60,7 @@
 #define	FREQUENCY_SAMPLES	8	/* samples for est. of permanent drift */
 #define	MAX_FREQUENCY_ADJUST	128e-5	/* max correction per iteration */
 #define REPORT_INTERVAL		(24*60*60) /* interval between status reports */
+#define MAX_SEND_ERRORS		3	/* max send errors before reconnect */
 
 
 #define	SENSOR_DATA_MAXAGE	(15*60)
@@ -130,6 +131,7 @@ struct ntp_peer {
 	u_int8_t			 trustlevel;
 	u_int8_t			 weight;
 	int				 lasterror;
+	int				 senderrors;
 };
 
 struct ntp_sensor {