[OpenWrt-Devel] [PATCH] netifd: Prevent flapping IPv6 routes

Kristian Evensen kristian.evensen at gmail.com
Fri Sep 18 07:13:10 EDT 2015

From: Kristian Evensen <kristian.evensen at gmail.com>

Comparing valid_until will always return false as the value is updated for each
route update message. This causes IPv6 routes to jump more around than House of
Pain, which might have undesirable consequences for user-space and user-space

Removing the valid_until comparison when setting keep fixes this problem, and
seems to have no side-effects. I am no IPv6 expert, but I see that valid of the
route is updated correctly and route is deleted if I block the route update

Signed-off-by: Kristian Evensen <kristian.evensen at gmail.com>
 interface-ip.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/interface-ip.c b/interface-ip.c
index 8eb2ff3..4a2ee35 100644
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -591,7 +591,7 @@ interface_update_proto_route(struct vlist_tree *tree,
 	if (node_old && node_new)
 		keep = !memcmp(&route_old->nexthop, &route_new->nexthop, sizeof(route_old->nexthop)) &&
 			(route_old->mtu == route_new->mtu) && (route_old->type == route_new->type) &&
-			(route_old->valid_until == route_new->valid_until) && !route_old->failed;
+			!route_old->failed;
 	if (node_old) {
 		if (!(route_old->flags & DEVADDR_EXTERNAL) && route_old->enabled && !keep)
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