arp: flush arp cache on IFF_NOARP change

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
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index bf57402..4429b01 100644 (file)
--- 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;
        }