[BRIDGE]: drop PAUSE frames

Pause frames should never make it out of the network device into
the stack. But if a device was misconfigured, it might happen.
So drop pause frames in bridge.
Signed-off-by: NStephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/if_ether.h

@@ -61,6 +61,7 @@
 #define ETH_P_8021Q	0x8100          /* 802.1Q VLAN Extended Header  */
 #define ETH_P_IPX	0x8137		/* IPX over DIX			*/
 #define ETH_P_IPV6	0x86DD		/* IPv6 over bluebook		*/
+#define ETH_P_PAUSE	0x8808		/* IEEE Pause frames. See 802.3 31B */
 #define ETH_P_SLOW	0x8809		/* Slow Protocol. See 802.3ad 43B */
 #define ETH_P_WCCP	0x883E		/* Web-cache coordination protocol
 					 * defined in draft-wilson-wrec-wccp-v2-00.txt */

net/bridge/br_input.c

@@ -131,9 +131,14 @@ struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb)
 	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
 		goto drop;
 
-	if (unlikely(is_link_local(dest)))
+	if (unlikely(is_link_local(dest))) {
+		/* Pause frames shouldn't be passed up by driver anyway */
+		if (skb->protocol == htons(ETH_P_PAUSE))
+			goto drop;
+
 		return (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
 				NULL, br_handle_local_finish) == 0) ? skb : NULL;
+	}
 
 	switch (p->state) {
 	case BR_STATE_FORWARDING: