net: add ARP notify option for devices

This adds another inet device option to enable gratuitous ARP
when device is brought up or address change. This is handy for
clusters or virtualization.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 0 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 309997edc8a5..d519a6a66726 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1075,6 +1075,14 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
                         }
                 }
                 ip_mc_up(in_dev);
+                /* fall through */
+        case NETDEV_CHANGEADDR:
+                if (IN_DEV_ARP_NOTIFY(in_dev))
+                        arp_send(ARPOP_REQUEST, ETH_P_ARP,
+                                 in_dev->ifa_list->ifa_address,
+                                 dev,
+                                 in_dev->ifa_list->ifa_address,
+                                 NULL, dev->dev_addr, NULL);
                 break;
         case NETDEV_DOWN:
                 ip_mc_down(in_dev);
@@ -1439,6 +1447,7 @@ static struct devinet_sysctl_table {
                 DEVINET_SYSCTL_RW_ENTRY(ARP_ANNOUNCE, "arp_announce"),
                 DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"),
                 DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"),
+                DEVINET_SYSCTL_RW_ENTRY(ARP_NOTIFY, "arp_notify"),
 
                 DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"),
                 DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"),