Introduce rtisvalid(9) a function to check if a (cached) route entry

can be used or should be released by rtfree(9).

It currently checks if the route is UP and is not attached to a stall
ifa.

ok bluhm@, claudio@

4 files changed, 44 insertions, 15 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 47ee2f46a23..67f2460b8d1 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.239 2015/09/01 03:47:58 dlg Exp $
+#	$OpenBSD: Makefile,v 1.240 2015/09/01 12:50:03 mpi Exp $
 #	$NetBSD: Makefile,v 1.4 1996/01/09 03:23:01 thorpej Exp $
 
 #	Makefile for section 9 (kernel function and variable) manual pages.
@@ -332,7 +332,7 @@ MLINKS+=rt_timer_add.9 rt_timer_queue_create.9 \
 	rt_timer_add.9 rt_timer_queue_change.9 \
 	rt_timer_add.9 rt_timer_queue_destroy.9 \
 	rt_timer_add.9 rt_timer_remove_all.9
-MLINKS+=rtalloc.9 rtalloc_mpath.9 rtalloc.9 rtfree.9
+MLINKS+=rtalloc.9 rtalloc_mpath.9 rtalloc.9 rtisvalid.9 rtalloc.9 rtfree.9
 MLINKS+=rtable_add.9 rtable_exists.9 rtable_add.9 rtable_get.9 \
 	rtable_add.9 rtable_l2.9 rtable_add.9 rtable_l2set.9
 MLINKS+=rtlabel_id2name.9 rtlabel_name2id.9 \
diff --git a/share/man/man9/rtalloc.9 b/share/man/man9/rtalloc.9
index 1b3afe47fd6..6bb32c2ed60 100644
--- a/share/man/man9/rtalloc.9
+++ b/share/man/man9/rtalloc.9
@@ -1,6 +1,6 @@
-.\" $OpenBSD: rtalloc.9,v 1.3 2014/12/05 16:55:53 schwarze Exp $
+.\" $OpenBSD: rtalloc.9,v 1.4 2015/09/01 12:50:03 mpi Exp $
 .\"
-.\" Copyright (c) 2014 Martin Pieuchot
+.\" Copyright (c) 2014-2015 Martin Pieuchot
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above
@@ -14,12 +14,13 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: December 5 2014 $
+.Dd $Mdocdate: September 1 2015 $
 .Dt RTALLOC 9
 .Os
 .Sh NAME
 .Nm rtalloc ,
 .Nm rtalloc_mpath ,
+.Nm rtisvalid,
 .Nm rtfree
 .Nd routing entry interface
 .Sh SYNOPSIS
@@ -30,6 +31,8 @@
 .Fn rtalloc "struct sockaddr *dst" "int flags" "unsigned int rtableid"
 .Ft struct rtentry *
 .Fn rtalloc_mpath "struct sockaddr *dst" "uint32_t *src" "unsigned int rtableid"
+.Ft int
+.Fn rtisvalid "struct rtentry *rt"
 .Ft void
 .Fn rtfree "struct rtentry *rt"
 .Sh DESCRIPTION
@@ -65,6 +68,14 @@ but selects a multipath routing entry corresponding to
 when possible.
 .Pp
 The
+.Fn rtisvalid
+function checks if the route entry
+.Fa rt
+is still valid and can be used.
+Cached entries that are no longer valid should be released by calling
+.Fn rtfree .
+.Pp
+The
 .Fn rtfree
 function releases a reference to the routing entry
 .Fa rt ,
@@ -72,9 +83,13 @@ freeing it if the reference count drops to 0.
 .Sh CONTEXT
 .Fn rtalloc ,
 .Fn rtalloc_mpath ,
+.Fn rtisvalid ,
 and
 .Fn rtfree
 can be called during autoconf, from process context, or from interrupt context.
+.Sh RETURN VALUES
+.Fn rtisvalid
+returns 1 if the route entry is valid, otherwise 0.
 .Sh SEE ALSO
 .Xr route 4 ,
 .Xr rtrequest1 9
diff --git a/sys/net/route.c b/sys/net/route.c
index 7ae25cb5a93..b6b5e7e03d7 100644
--- a/sys/net/route.c
+++ b/sys/net/route.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: route.c,v 1.227 2015/09/01 10:04:51 mpi Exp $	*/
+/*	$OpenBSD: route.c,v 1.228 2015/09/01 12:50:03 mpi Exp $	*/
 /*	$NetBSD: route.c,v 1.14 1996/02/13 22:00:46 christos Exp $	*/
 
 /*
@@ -300,6 +300,25 @@ rtable_exists(u_int id)	/* verify table with that ID exists */
 	return (1);
 }
 
+/*
+ * Returns 1 if the (cached) ``rt'' entry is still valid, 0 otherwise.
+ */
+int
+rtisvalid(struct rtentry *rt)
+{
+	if (rt == NULL)
+		return (0);
+
+	if ((rt->rt_flags & RTF_UP) == 0)
+		return (0);
+
+	/* Routes attached to stall ifas should be freed. */
+	if (rt->rt_ifa == NULL || rt->rt_ifa->ifa_ifp == NULL)
+		return (0);
+
+	return (1);
+}
+
 struct rtentry *
 rtalloc(struct sockaddr *dst, int flags, unsigned int tableid)
 {
@@ -659,19 +678,13 @@ ifa_ifwithroute(int flags, struct sockaddr *dst, struct sockaddr *gateway,
 	}
 	if (ifa == NULL) {
 		struct rtentry	*rt = rtalloc(gateway, 0, rtableid);
-		if (rt == NULL)
-			return (NULL);
 		/* The gateway must be local if the same address family. */
-		if ((rt->rt_flags & RTF_GATEWAY) &&
-		    rt_key(rt)->sa_family == dst->sa_family) {
+		if (!rtisvalid(rt) || ((rt->rt_flags & RTF_GATEWAY) &&
+		    rt_key(rt)->sa_family == dst->sa_family)) {
 			rtfree(rt);
 			return (NULL);
 		}
 		ifa = rt->rt_ifa;
-		if (ifa == NULL || ifa->ifa_ifp == NULL) {
-			rtfree(rt);
-			return (NULL);
-		}
 		rtfree(rt);
 	}
 	if (ifa->ifa_addr->sa_family != dst->sa_family) {
diff --git a/sys/net/route.h b/sys/net/route.h
index 5491b45ccab..26d58590cc4 100644
--- a/sys/net/route.h
+++ b/sys/net/route.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: route.h,v 1.110 2015/08/20 12:39:43 mpi Exp $	*/
+/*	$OpenBSD: route.h,v 1.111 2015/09/01 12:50:03 mpi Exp $	*/
 /*	$NetBSD: route.h,v 1.9 1996/02/13 22:00:49 christos Exp $	*/
 
 /*
@@ -377,6 +377,7 @@ void			 rt_timer_queue_destroy(struct rttimer_queue *);
 unsigned long		 rt_timer_queue_count(struct rttimer_queue *);
 void			 rt_timer_timer(void *);
 
+int	 rtisvalid(struct rtentry *);
 #ifdef SMALL_KERNEL
 #define	 rtalloc_mpath(dst, s, rid) rtalloc((dst), RT_REPORT|RT_RESOLVE, (rid))
 #else