PRESTERA_DSA_HLEN
if (unlikely(!pskb_may_pull(skb, PRESTERA_DSA_HLEN)))
skb_pull_rcsum(skb, PRESTERA_DSA_HLEN);
memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - PRESTERA_DSA_HLEN,
port->dev->needed_headroom = PRESTERA_DSA_HLEN;
if (skb_cow_head(skb, PRESTERA_DSA_HLEN) < 0)
skb_push(skb, PRESTERA_DSA_HLEN);
memmove(skb->data, skb->data + PRESTERA_DSA_HLEN, 2 * ETH_ALEN);