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authorIan Campbell <Ian.Campbell@citrix.com>2010-05-26 00:09:42 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-10 11:09:15 -0700
commit9bfcb1f838ee0825bed898ff34aee2010763499a (patch)
treef57e26da3542cec6322c58d0acfe60118237b573 /net
parent69e18d28ab99ba499e2afba725f16a22f7424a4e (diff)
downloadlinux-2.6.34-ux500-9bfcb1f838ee0825bed898ff34aee2010763499a.tar.gz
arp_notify: allow drivers to explicitly request a notification event.
commit 06c4648d46d1b757d6b9591a86810be79818b60c upstream. Currently such notifications are only generated when the device comes up or the address changes. However one use case for these notifications is to enable faster network recovery after a virtual machine migration (by causing switches to relearn their MAC tables). A migration appears to the network stack as a temporary loss of carrier and therefore does not trigger either of the current conditions. Rather than adding carrier up as a trigger (which can cause issues when interfaces a flapping) simply add an interface which the driver can use to explicitly trigger the notification. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Stephen Hemminger <shemminger@linux-foundation.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: David S. Miller <davem@davemloft.net> Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/devinet.c1
-rw-r--r--net/sched/sch_generic.c18
2 files changed, 19 insertions, 0 deletions
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 382bc768ed5..da14c49284f 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1081,6 +1081,7 @@ 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:
/* Send gratuitous ARP to notify of link change */
if (IN_DEV_ARP_NOTIFY(in_dev)) {
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index a63029ef3ed..bd1892fe4b2 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -327,6 +327,24 @@ void netif_carrier_off(struct net_device *dev)
}
EXPORT_SYMBOL(netif_carrier_off);
+/**
+ * netif_notify_peers - notify network peers about existence of @dev
+ * @dev: network device
+ *
+ * Generate traffic such that interested network peers are aware of
+ * @dev, such as by generating a gratuitous ARP. This may be used when
+ * a device wants to inform the rest of the network about some sort of
+ * reconfiguration such as a failover event or virtual machine
+ * migration.
+ */
+void netif_notify_peers(struct net_device *dev)
+{
+ rtnl_lock();
+ call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
+ rtnl_unlock();
+}
+EXPORT_SYMBOL(netif_notify_peers);
+
/* "NOOP" scheduler: the best scheduler, recommended for all interfaces
under all circumstances. It is difficult to invent anything faster or
cheaper.