arp: Do not perturb drop profiles with ignored ARP packets

We do not wish to disturb dropwatch or perf drop profiles with an ARP
we will ignore.

Signed-off-by: Rick Jones <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/arp.c

···
 {
 	const struct arphdr *arp;
 
+	/* do not tweak dropwatch on an ARP we will ignore */
 	if (dev->flags & IFF_NOARP ||
 	    skb->pkt_type == PACKET_OTHERHOST ||
 	    skb->pkt_type == PACKET_LOOPBACK)
-		goto freeskb;
+		goto consumeskb;
 
 	skb = skb_share_check(skb, GFP_ATOMIC);
 	if (!skb)
···
 
 	return NF_HOOK(NFPROTO_ARP, NF_ARP_IN, skb, dev, NULL, arp_process);
 
+consumeskb:
+	consume_skb(skb);
+	return 0;
 freeskb:
 	kfree_skb(skb);
 out_of_mem: