Terminate with extreme prejudice the multiple timeout queuing

mechanism that was a holdover from when dhclient handled multiple
interfaces at once. There is only one timeout possible at a time.

Also move calculation of current time to just before check to see
if the timeout has expired.

ok beck@ guenther@

3 files changed, 33 insertions, 115 deletions

diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index 3c667bc9315..90308927d28 100644
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhclient.c,v 1.145 2012/06/24 16:01:18 krw Exp $	*/
+/*	$OpenBSD: dhclient.c,v 1.146 2012/07/09 16:21:21 krw Exp $	*/
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -470,11 +470,7 @@ state_reboot(void)
 {
 	/* Cancel all timeouts, since a link state change gets us here
 	   and can happen anytime. */
-	cancel_timeout(state_init);
-	cancel_timeout(state_selecting);
-	cancel_timeout(state_bound);
-	cancel_timeout(send_discover);
-	cancel_timeout(send_request);
+	cancel_timeout();
 
 	/* If we don't remember an active lease, go straight to INIT. */
 	if (!client->active || client->active->is_bootp) {
@@ -531,8 +527,7 @@ state_selecting(void)
 
 	/* Cancel state_selecting and send_discover timeouts, since either
 	   one could have got us here. */
-	cancel_timeout(state_selecting);
-	cancel_timeout(send_discover);
+	cancel_timeout();
 
 	/* We have received one or more DHCPOFFER packets.   Currently,
 	   the only criterion by which we judge leases is whether or
@@ -614,7 +609,7 @@ dhcpack(struct iaddr client_addr, struct option_data *options)
 	client->new = lease;
 
 	/* Stop resending DHCPREQUEST. */
-	cancel_timeout(send_request);
+	cancel_timeout();
 
 	/* Figure out the lease time. */
 	if (client->new->options[DHO_DHCP_LEASE_TIME].data)
@@ -681,8 +676,8 @@ bind_lease(void)
 	/* Write out new leases file. */
 	rewrite_client_leases();
 
-	/* Set up a timeout to start the renewal process. */
-	add_timeout(client->active->renewal, state_bound);
+	/* Set timeout to start the renewal process. */
+	set_timeout(client->active->renewal, state_bound);
 
 	note("bound to %s -- renewal in %d seconds.",
 	    piaddr(client->active->address),
@@ -793,8 +788,7 @@ dhcpoffer(struct iaddr client_addr, struct option_data *options)
 	if (stop_selecting <= cur_time)
 		state_selecting();
 	else {
-		add_timeout(stop_selecting, state_selecting);
-		cancel_timeout(send_discover);
+		set_timeout(stop_selecting, state_selecting);
 	}
 }
 
@@ -890,7 +884,7 @@ dhcpnak(struct iaddr client_addr, struct option_data *options)
 	client->active = NULL;
 
 	/* Stop sending DHCPREQUEST packets... */
-	cancel_timeout(send_request);
+	cancel_timeout();
 
 	client->state = S_INIT;
 	state_init();
@@ -960,7 +954,7 @@ send_discover(void)
 	/* Send out a packet. */
 	send_packet(inaddr_any, &sockaddr_broadcast, NULL);
 
-	add_timeout(cur_time + client->interval, send_discover);
+	set_timeout(cur_time + client->interval, send_discover);
 }
 
 /*
@@ -1002,7 +996,7 @@ state_panic(void)
 					note("bound: renewal in %d seconds.",
 					    client->active->renewal -
 					    cur_time);
-					add_timeout(client->active->renewal,
+					set_timeout(client->active->renewal,
 					    state_bound);
 				} else {
 					client->state = S_BOUND;
@@ -1049,7 +1043,7 @@ activate_next:
 	script_init("FAIL");
 	script_go();
 	client->state = S_INIT;
-	add_timeout(cur_time + config->retry_interval, state_init);
+	set_timeout(cur_time + config->retry_interval, state_init);
 	go_daemon();
 }
 
@@ -1077,7 +1071,7 @@ send_request(void)
 	    client->state == S_REQUESTING) &&
 	    interval > config->reboot_timeout) {
 		client->state = S_INIT;
-		cancel_timeout(send_request);
+		cancel_timeout();
 		state_init();
 		return;
 	}
@@ -1149,7 +1143,7 @@ send_request(void)
 	/* Send out a packet. */
 	send_packet(from, &destination, NULL);
 
-	add_timeout(cur_time + client->interval, send_request);
+	set_timeout(cur_time + client->interval, send_request);
 }
 
 void
diff --git a/sbin/dhclient/dhcpd.h b/sbin/dhclient/dhcpd.h
index f2cc00b27d7..13968245cbd 100644
--- a/sbin/dhclient/dhcpd.h
+++ b/sbin/dhclient/dhcpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhcpd.h,v 1.75 2012/06/24 16:01:18 krw Exp $	*/
+/*	$OpenBSD: dhcpd.h,v 1.76 2012/07/09 16:21:21 krw Exp $	*/
 
 /*
  * Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
@@ -251,8 +251,8 @@ void discover_interface(void);
 void reinitialize_interface(void);
 void dispatch(void);
 void got_one(void);
-void add_timeout(time_t, void (*)(void));
-void cancel_timeout(void (*)(void));
+void set_timeout(time_t, void (*)(void));
+void cancel_timeout(void);
 int interface_status(char *);
 int interface_link_forceup(char *);
 int get_rdomain(char *);
diff --git a/sbin/dhclient/dispatch.c b/sbin/dhclient/dispatch.c
index 6bc23353711..399da2f249f 100644
--- a/sbin/dhclient/dispatch.c
+++ b/sbin/dhclient/dispatch.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dispatch.c,v 1.51 2012/06/24 16:01:18 krw Exp $	*/
+/*	$OpenBSD: dispatch.c,v 1.52 2012/07/09 16:21:21 krw Exp $	*/
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -47,8 +47,7 @@
 #include <ifaddrs.h>
 #include <poll.h>
 
-struct timeout *timeouts;
-static struct timeout *free_timeouts;
+struct timeout timeout;
 static int interfaces_invalidated;
 
 /*
@@ -124,10 +123,11 @@ dispatch(void)
 	int count, to_msec;
 	struct pollfd fds[2];
 	time_t howlong;
+	void (*func)(void);
 
 	do {
 		/*
-		 * Call any expired timeouts, and then if there's still
+		 * Call expired timeout, and then if there's still
 		 * a timeout registered, time out the select call then.
 		 */
 another:
@@ -142,25 +142,21 @@ another:
 			    " rdomain changed out from under us",
 			    ifi->name);
 
-		if (timeouts) {
-			struct timeout *t;
-
-			if (timeouts->when <= cur_time) {
-				t = timeouts;
-				timeouts = timeouts->next;
-				(*(t->func))();
-				t->next = free_timeouts;
-				free_timeouts = t;
+		if (timeout.func) {
+			time(&cur_time);
+			if (timeout.when <= cur_time) {
+				func = timeout.func;
+				cancel_timeout();
+				(*(func))();
 				goto another;
 			}
-
 			/*
 			 * Figure timeout in milliseconds, and check for
 			 * potential overflow, so we can cram into an
 			 * int for poll, while not polling with a
 			 * negative timeout and blocking indefinitely.
 			 */
-			howlong = timeouts->when - cur_time;
+			howlong = timeout.when - cur_time;
 			if (howlong > INT_MAX / 1000)
 				howlong = INT_MAX / 1000;
 			to_msec = howlong * 1000;
@@ -178,9 +174,6 @@ another:
 		/* Wait for a packet or a timeout... XXX */
 		count = poll(fds, 2, to_msec);
 
-		/* Get the current time... */
-		time(&cur_time);
-
 		/* Not likely to be transitory... */
 		if (count == -1) {
 			if (errno == EAGAIN || errno == EINTR) {
@@ -317,86 +310,17 @@ active:
 }
 
 void
-add_timeout(time_t when, void (*where)(void))
+set_timeout(time_t when, void (*where)(void))
 {
-	struct timeout *t, *q;
-
-	/* See if this timeout supersedes an existing timeout. */
-	t = NULL;
-	for (q = timeouts; q; q = q->next) {
-		if (q->func == where) {
-			if (t)
-				t->next = q->next;
-			else
-				timeouts = q->next;
-			break;
-		}
-		t = q;
-	}
-
-	/* If we didn't supersede a timeout, allocate a timeout
-	   structure now. */
-	if (!q) {
-		if (free_timeouts) {
-			q = free_timeouts;
-			free_timeouts = q->next;
-			q->func = where;
-		} else {
-			q = malloc(sizeof(struct timeout));
-			if (!q)
-				error("Can't allocate timeout structure!");
-			q->func = where;
-		}
-	}
-
-	q->when = when;
-
-	/* Now sort this timeout into the timeout list. */
-
-	/* Beginning of list? */
-	if (!timeouts || timeouts->when > q->when) {
-		q->next = timeouts;
-		timeouts = q;
-		return;
-	}
-
-	/* Middle of list? */
-	for (t = timeouts; t->next; t = t->next) {
-		if (t->next->when > q->when) {
-			q->next = t->next;
-			t->next = q;
-			return;
-		}
-	}
-
-	/* End of list. */
-	t->next = q;
-	q->next = NULL;
+	timeout.when = when;
+	timeout.func = where;
 }
 
 void
-cancel_timeout(void (*where)(void))
+cancel_timeout(void)
 {
-	struct timeout *t, *q;
-
-	/* Look for this timeout on the list, and unlink it if we find it. */
-	t = NULL;
-	for (q = timeouts; q; q = q->next) {
-		if (q->func == where) {
-			if (t)
-				t->next = q->next;
-			else
-				timeouts = q->next;
-			break;
-		}
-		t = q;
-	}
-
-	/* If we found the timeout, put it on the free list. */
-	if (q) {
-		q->next = free_timeouts;
-		free_timeouts = q;
-	}
+	timeout.when = 0;
+	timeout.func = NULL;
 }
 
 int