Rather than reloading kernel routes immediately when an RTM_DESYNC is seen,

set (or extend) a timer and only reload when this expires. Avoids repeatedly
dumping full kernel routes (thus generating more load) when the machine has
problems keeping up with messages on the route socket. (if you see lots of
repeated "reloading interface list and routing table" in ospfd logs, this
will help).

Suggestions/ok claudio@.

2 files changed, 56 insertions, 8 deletions

diff --git a/usr.sbin/ospfd/kroute.c b/usr.sbin/ospfd/kroute.c
index 67c4414f140..dd6f8f03c82 100644
--- a/usr.sbin/ospfd/kroute.c
+++ b/usr.sbin/ospfd/kroute.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kroute.c,v 1.90 2011/07/04 04:34:14 claudio Exp $ */
+/*	$OpenBSD: kroute.c,v 1.91 2011/09/16 18:24:57 sthen Exp $ */
 
 /*
  * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
@@ -47,7 +47,12 @@ struct {
 	int			fib_serial;
 	int			fd;
 	struct event		ev;
+	struct event		reload;
 	u_int			rdomain;
+#define KR_RELOAD_IDLE	0
+#define KR_RELOAD_FETCH	1
+#define KR_RELOAD_HOLD	2
+	int			reload_state;
 } kr_state;
 
 struct kroute_node {
@@ -102,6 +107,8 @@ int		dispatch_rtmsg(void);
 int		fetchtable(void);
 int		fetchifs(u_short);
 int		rtmsg_process(char *, int);
+void		kr_fib_reload_timer(int, short, void *);
+void		kr_fib_reload_arm_timer(int);
 
 RB_HEAD(kroute_tree, kroute_node)	krt;
 RB_PROTOTYPE(kroute_tree, kroute_node, entry, kroute_compare)
@@ -170,6 +177,9 @@ kr_init(int fs, u_int rdomain)
 	    kr_dispatch_msg, NULL);
 	event_add(&kr_state.ev, NULL);
 
+	kr_state.reload_state = KR_RELOAD_IDLE;
+	evtimer_set(&kr_state.reload, kr_fib_reload_timer, NULL);
+
 	return (0);
 }
 
@@ -357,7 +367,32 @@ kr_fib_decouple(void)
 }
 
 void
-kr_fib_reload(void)
+kr_fib_reload_timer(int fd, short event, void *bula)
+{
+	if (kr_state.reload_state == KR_RELOAD_FETCH) {
+		kr_fib_reload();
+		kr_state.reload_state = KR_RELOAD_HOLD;
+		kr_fib_reload_arm_timer(KR_RELOAD_HOLD_TIMER);
+	} else {
+		kr_state.reload_state = KR_RELOAD_IDLE;
+	}
+}
+
+void
+kr_fib_reload_arm_timer(int delay)
+{
+	struct timeval		 tv;
+
+	timerclear(&tv);
+	tv.tv_sec = delay / 1000;
+	tv.tv_usec = (delay % 1000) * 1000;
+
+	if (evtimer_add(&kr_state.reload, &tv) == -1)
+		fatal("add_reload_timer");
+}
+
+void
+kr_fib_reload()
 {
 	struct kroute_node	*krn, *kr, *kn;
 
@@ -1172,7 +1207,6 @@ send_rtmsg(int fd, int action, struct kroute *kroute)
 		iov[iovcnt++].iov_len = sizeof(sa_rl);
 	}
 
-
 retry:
 	if (writev(fd, iov, iovcnt) == -1) {
 		if (errno == ESRCH) {
@@ -1298,7 +1332,7 @@ rtmsg_process(char *buf, int len)
 	u_int8_t		 prefixlen, prio;
 	int			 flags, mpath;
 	u_short			 ifindex = 0;
-	int			 rv;
+	int			 rv, delay;
 
 	int			 offset;
 	char			*next;
@@ -1524,10 +1558,20 @@ add:
 			break;
 		case RTM_DESYNC:
 			/*
-			 * We lost some routing packets. Force a reload of
-			 * the kernel route/interface information.
+			 * We lost some routing packets. Schedule a reload
+			 * of the kernel route/interface information.
 			 */
-			kr_fib_reload();
+			if (kr_state.reload_state == KR_RELOAD_IDLE) {
+				delay = KR_RELOAD_TIMER;
+				log_info("desync; scheduling fib reload");
+			} else {
+				delay = KR_RELOAD_HOLD_TIMER;
+				log_debug("desync during KR_RELOAD_%s",
+				    kr_state.reload_state ==
+				    KR_RELOAD_FETCH ? "FETCH" : "HOLD");
+			}
+			kr_state.reload_state = KR_RELOAD_FETCH;
+			kr_fib_reload_arm_timer(delay);
 			break;
 		default:
 			/* ignore for now */
diff --git a/usr.sbin/ospfd/ospf.h b/usr.sbin/ospfd/ospf.h
index fe0a8998ffc..f4077a1f9ef 100644
--- a/usr.sbin/ospfd/ospf.h
+++ b/usr.sbin/ospfd/ospf.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ospf.h,v 1.21 2011/05/09 12:24:41 claudio Exp $ */
+/*	$OpenBSD: ospf.h,v 1.22 2011/09/16 18:24:57 sthen Exp $ */
 
 /*
  * Copyright (c) 2004, 2005 Esben Norby <norby@openbsd.org>
@@ -75,6 +75,10 @@
 #define MIN_SPF_HOLDTIME	10
 #define MAX_SPF_HOLDTIME	5000
 
+/* msec */
+#define KR_RELOAD_TIMER		250
+#define KR_RELOAD_HOLD_TIMER	5000
+
 #define MIN_MD_ID		0
 #define MAX_MD_ID		255