@@ -1661,6 +1661,8 @@ extern void netif_carrier_on(struct net_device *dev);
extern void netif_carrier_off(struct net_device *dev);
+extern void netif_notify_peers(struct net_device *dev);
+
/**
* netif_dormant_on - mark device as dormant.
* @dev: network device
@@ -203,6 +203,7 @@ static inline int notifier_to_errno(int ret)
#define NETDEV_BONDING_NEWTYPE 0x000F
#define NETDEV_POST_INIT 0x0010
#define NETDEV_UNREGISTER_BATCH 0x0011
+#define NETDEV_NOTIFY_PEERS 0x0012
#define SYS_DOWN 0x0001 /* Notify of system down */
#define SYS_RESTART SYS_DOWN
@@ -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)) {
@@ -325,6 +325,24 @@ 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.
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 Cc: stable@kernel.org --- include/linux/netdevice.h | 2 ++ include/linux/notifier.h | 1 + net/ipv4/devinet.c | 1 + net/sched/sch_generic.c | 18 ++++++++++++++++++ 4 files changed, 22 insertions(+), 0 deletions(-)