[patch net-next v3 3/3] arp: flush arp cache on IFF_NOARP change

[Jiri Pirko <jiri@resnulli.us>]

From: Timo Teräs <timo.teras@iki.fi>

IFF_NOARP affects what kind of neighbor entries are created
(nud NOARP or nud INCOMPLETE). If the flag changes, flush the arp
cache to refresh all entries.

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>

v2->v3: shortened notifier_info struct name
---
 net/ipv4/arp.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index bf57402..4429b01 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -1235,12 +1235,18 @@ static int arp_netdev_event(struct notifier_block *this, unsigned long event,
 			    void *ptr)
 {
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct netdev_notifier_change_info *change_info;
 
 	switch (event) {
 	case NETDEV_CHANGEADDR:
 		neigh_changeaddr(&arp_tbl, dev);
 		rt_cache_flush(dev_net(dev));
 		break;
+	case NETDEV_CHANGE:
+		change_info = ptr;
+		if (change_info->flags_changed & IFF_NOARP)
+			neigh_changeaddr(&arp_tbl, dev);
+		break;
 	default:
 		break;
 	}
-- 
1.7.11.7