RTL4_A_HDR_LEN
skb_pull_rcsum(skb, RTL4_A_HDR_LEN);
dsa_strip_etype_header(skb, RTL4_A_HDR_LEN);
.needed_headroom = RTL4_A_HDR_LEN,
skb_push(skb, RTL4_A_HDR_LEN);
dsa_alloc_etype_header(skb, RTL4_A_HDR_LEN);
if (unlikely(!pskb_may_pull(skb, RTL4_A_HDR_LEN)))