net/core: Allow certain receives on inactive slave.

Allow a packet_type that specifies the exact device to receive
even on an inactive bonding slave devices.  This is important for some
L2 protocols such as LLDP and FCoE.  This can eventually be used
for the bonding special cases as well.
Signed-off-by: Joe Eykholt <jre@nuovasystems.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

net/core/dev.c

@@ -2165,6 +2165,7 @@ int netif_receive_skb(struct sk_buff *skb)
 {
 	struct packet_type *ptype, *pt_prev;
 	struct net_device *orig_dev;
+	struct net_device *null_or_orig;
 	int ret = NET_RX_DROP;
 	__be16 type;
 
@@ -2178,12 +2179,12 @@ int netif_receive_skb(struct sk_buff *skb)
 	if (!skb->iif)
 		skb->iif = skb->dev->ifindex;
 
+	null_or_orig = NULL;
 	orig_dev = skb->dev;
 	if (orig_dev->master) {
-		if (skb_bond_should_drop(skb)) {
-			kfree_skb(skb);
-			return NET_RX_DROP;
-		}
+		if (skb_bond_should_drop(skb))
+			null_or_orig = orig_dev; /* deliver only exact match */
+		else
 			skb->dev = orig_dev->master;
 	}
 
@@ -2209,7 +2210,7 @@ int netif_receive_skb(struct sk_buff *skb)
 #endif
 
 	list_for_each_entry_rcu(ptype, &ptype_all, list) {
-		if (!ptype->dev || ptype->dev == skb->dev) {
+		if (ptype->dev == null_or_orig || ptype->dev == skb->dev) {
 			if (pt_prev)
 				ret = deliver_skb(skb, pt_prev, orig_dev);
 			pt_prev = ptype;
@@ -2234,7 +2235,7 @@ int netif_receive_skb(struct sk_buff *skb)
 	list_for_each_entry_rcu(ptype,
 			&ptype_base[ntohs(type) & PTYPE_HASH_MASK], list) {
 		if (ptype->type == type &&
-		    (!ptype->dev || ptype->dev == skb->dev)) {
+		    (ptype->dev == null_or_orig || ptype->dev == skb->dev)) {
 			if (pt_prev)
 				ret = deliver_skb(skb, pt_prev, orig_dev);
 			pt_prev = ptype;