act_mirred: Fix bogus header when redirecting from VLAN

When you redirect a VLAN device to any device, you end up with
crap in af_packet on the xmit path because hard_header_len is
not equal to skb->mac_len.  So the redirected packet contains
four extra bytes at the start which then gets interpreted as
part of the MAC address.

This patch fixes this by only pushing skb->mac_len.  We also
need to fix ifb because it tries to undo the pushing done by
act_mirred.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ifb.c

@@ -105,7 +105,7 @@ static void ri_tasklet(unsigned long dev)
 		if (from & AT_EGRESS) {
 			dev_queue_xmit(skb);
 		} else if (from & AT_INGRESS) {
-			skb_pull(skb, skb->dev->hard_header_len);
+			skb_pull(skb, skb->mac_len);
 			netif_receive_skb(skb);
 		} else
 			BUG();

net/sched/act_mirred.c

@@ -157,7 +157,7 @@ static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
 
 	if (!(at & AT_EGRESS)) {
 		if (m->tcfm_ok_push)
-			skb_push(skb2, skb2->dev->hard_header_len);
+			skb_push(skb2, skb->mac_len);
 	}
 
 	/* mirror is always swallowed */