[PATCH] bonding: Validate probe replies in ARP monitor

	Add logic to check ARP request / reply packets used for ARP
monitor link integrity checking.

	The current method simply examines the slave device to see if it
has sent and received traffic; this can be fooled by extraneous traffic.
For example, if multiple hosts running bonding are behind a common
switch, the probe traffic from the multiple instances of bonding will
update the tx/rx times on each other's slave devices.

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 7 insertions, 1 deletions

diff --git a/include/linux/if.h b/include/linux/if.h
index a023ec1274fe..8018c2e22c0c 100644
--- a/include/linux/if.h
+++ b/include/linux/if.h
@@ -60,6 +60,7 @@
 #define IFF_MASTER_8023AD       0x8     /* bonding master, 802.3ad.     */
 #define IFF_MASTER_ALB  0x10            /* bonding master, balance-alb. */
 #define IFF_BONDING     0x20            /* bonding master or slave      */
+#define IFF_SLAVE_NEEDARP 0x40          /* need ARPs for validation     */
 
 #define IF_GET_IFACE    0x0001          /* for querying only */
 #define IF_GET_PROTO    0x0002
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 43289127b458..afd80eff2725 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1016,7 +1016,8 @@ static inline int netif_needs_gso(struct net_device *dev, struct sk_buff *skb)
 }
 
 /* On bonding slaves other than the currently active slave, suppress
- * duplicates except for 802.3ad ETH_P_SLOW and alb non-mcast/bcast.
+ * duplicates except for 802.3ad ETH_P_SLOW, alb non-mcast/bcast, and
+ * ARP on active-backup slaves with arp_validate enabled.
  */
 static inline int skb_bond_should_drop(struct sk_buff *skb)
 {
@@ -1025,6 +1026,10 @@ static inline int skb_bond_should_drop(struct sk_buff *skb)
 
         if (master &&
             (dev->priv_flags & IFF_SLAVE_INACTIVE)) {
+                if ((dev->priv_flags & IFF_SLAVE_NEEDARP) &&
+                    skb->protocol == __constant_htons(ETH_P_ARP))
+                        return 0;
+
                 if (master->priv_flags & IFF_MASTER_ALB) {
                         if (skb->pkt_type != PACKET_BROADCAST &&
                             skb->pkt_type != PACKET_MULTICAST)