[IPV6] Don't use expired default routes.

Signed-off-by: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>

net/ipv6/route.c

@@ -167,6 +167,12 @@ static void ip6_dst_ifdown(struct dst_entry *dst, int how)
 	}
 }
 
+static __inline__ int rt6_check_expired(const struct rt6_info *rt)
+{
+	return (rt->rt6i_flags & RTF_EXPIRES &&
+		time_after(jiffies, rt->rt6i_expires));
+}
+
 /*
  *	Route lookup. Any rt6_lock is implied.
  */
@@ -237,8 +243,7 @@ static struct rt6_info *rt6_best_dflt(struct rt6_info *rt, int oif)
 		     sprt->rt6i_dev->ifindex == oif))
 			m += 8;
 
-		if ((sprt->rt6i_flags & RTF_EXPIRES) &&
-		    time_after(jiffies, sprt->rt6i_expires))
+		if (rt6_check_expired(sprt))
 			continue;
 
 		if (sprt == rt6_dflt_pointer)
@@ -296,7 +301,8 @@ static struct rt6_info *rt6_best_dflt(struct rt6_info *rt, int oif)
 			for (sprt = rt6_dflt_pointer->u.next;
 			     sprt; sprt = sprt->u.next) {
 				if (sprt->u.dst.obsolete <= 0 &&
-				    sprt->u.dst.error == 0) {
+				    sprt->u.dst.error == 0 &&
+				    !rt6_check_expired(sprt)) {
 					match = sprt;
 					break;
 				}
@@ -305,7 +311,8 @@ static struct rt6_info *rt6_best_dflt(struct rt6_info *rt, int oif)
 			     !match && sprt;
 			     sprt = sprt->u.next) {
 				if (sprt->u.dst.obsolete <= 0 &&
-				    sprt->u.dst.error == 0) {
+				    sprt->u.dst.error == 0 &&
+				    !rt6_check_expired(sprt)) {
 					match = sprt;
 					break;
 				}
@@ -331,7 +338,8 @@ static struct rt6_info *rt6_best_dflt(struct rt6_info *rt, int oif)
 		 */
 		for (sprt = ip6_routing_table.leaf;
 		     sprt; sprt = sprt->u.next) {
-			if ((sprt->rt6i_flags & RTF_DEFAULT) &&
+			if (!rt6_check_expired(sprt) &&
+			    (sprt->rt6i_flags & RTF_DEFAULT) &&
 			    (!oif ||
 			     (sprt->rt6i_dev &&
 			      sprt->rt6i_dev->ifindex == oif))) {