ipv6: add knob to send unsolicited ND on link-layer address change

This patch introduces a new knob ndisc_notify. If enabled, the kernel
will transmit an unsolicited neighbour advertisement on link-layer address
change to update the neighbour tables of the corresponding hosts more quickly.

This is the equivalent to arp_notify in ipv4 world.

Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 6ba4b54a550a..f41853bca428 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1572,11 +1572,18 @@ static int ndisc_netdev_event(struct notifier_block *this, unsigned long event,
 {
         struct net_device *dev = ptr;
         struct net *net = dev_net(dev);
+        struct inet6_dev *idev;
 
         switch (event) {
         case NETDEV_CHANGEADDR:
                 neigh_changeaddr(&nd_tbl, dev);
                 fib6_run_gc(~0UL, net);
+                idev = in6_dev_get(dev);
+                if (!idev)
+                        break;
+                if (idev->cnf.ndisc_notify)
+                        ndisc_send_unsol_na(dev);
+                in6_dev_put(idev);
                 break;
         case NETDEV_DOWN:
                 neigh_ifdown(&nd_tbl, dev);