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authorIan Campbell <Ian.Campbell@citrix.com>2011-02-11 07:44:16 +0000
committerDavid S. Miller <davem@davemloft.net>2011-02-14 17:47:15 -0800
commitd11327ad6695db8117c78d70611e71102ceec2ac (patch)
tree02d76a5825c357d0383268d9502c886abc8c9987
parent0550769bb7f364fb9aeeb9412229fb7790ee79c4 (diff)
arp_notify: unconditionally send gratuitous ARP for NETDEV_NOTIFY_PEERS.
NETDEV_NOTIFY_PEER is an explicit request by the driver to send a link notification while NETDEV_UP/NETDEV_CHANGEADDR generate link notifications as a sort of side effect. In the later cases the sysctl option is present because link notification events can have undesired effects e.g. if the link is flapping. I don't think this applies in the case of an explicit request from a driver. This patch makes NETDEV_NOTIFY_PEER unconditional, if preferred we could add a new sysctl for this case which defaults to on. This change causes Xen post-migration ARP notifications (which cause switches to relearn their MAC tables etc) to be sent by default. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/devinet.c30
1 files changed, 20 insertions, 10 deletions
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 748cb5b337bd..df4616fce929 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1030,6 +1030,21 @@ static inline bool inetdev_valid_mtu(unsigned mtu)
return mtu >= 68;
}
+static void inetdev_send_gratuitous_arp(struct net_device *dev,
+ struct in_device *in_dev)
+
+{
+ struct in_ifaddr *ifa = in_dev->ifa_list;
+
+ if (!ifa)
+ return;
+
+ arp_send(ARPOP_REQUEST, ETH_P_ARP,
+ ifa->ifa_address, dev,
+ ifa->ifa_address, NULL,
+ dev->dev_addr, NULL);
+}
+
/* Called only under RTNL semaphore */
static int inetdev_event(struct notifier_block *this, unsigned long event,
@@ -1082,18 +1097,13 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
}
ip_mc_up(in_dev);
/* fall through */
- case NETDEV_NOTIFY_PEERS:
case NETDEV_CHANGEADDR:
+ if (!IN_DEV_ARP_NOTIFY(in_dev))
+ break;
+ /* fall through */
+ case NETDEV_NOTIFY_PEERS:
/* Send gratuitous ARP to notify of link change */
- if (IN_DEV_ARP_NOTIFY(in_dev)) {
- struct in_ifaddr *ifa = in_dev->ifa_list;
-
- if (ifa)
- arp_send(ARPOP_REQUEST, ETH_P_ARP,
- ifa->ifa_address, dev,
- ifa->ifa_address, NULL,
- dev->dev_addr, NULL);
- }
+ inetdev_send_gratuitous_arp(dev, in_dev);
break;
case NETDEV_DOWN:
ip_mc_down(in_dev);