skb->csum_offset = offsetof(struct tcphdr, check);
} else {
th->check = csum_ipv6_magic(&np->saddr, &np->daddr, len, IPPROTO_TCP,
skb->csum_offset = offsetof(struct tcphdr, check);
} else {
th->check = csum_ipv6_magic(&np->saddr, &np->daddr, len, IPPROTO_TCP,