udp_v4_check
uh->check = ~udp_v4_check(len, ip->saddr, ip->daddr, 0);
uh->check = ~udp_v4_check(skb->len - udp_off, ipv4->saddr,
uh->check = ~udp_v4_check(len, iph->saddr,
uh->check = udp_v4_check(ntohs(uh->len), iph->saddr,
uh->check = ~udp_v4_check(len, saddr, daddr, 0);
uh->check = udp_v4_check(len, saddr, daddr, lco_csum(skb));
uh->check = ~udp_v4_check(len, saddr, daddr, 0);
uh->check = ~udp_v4_check(gso_skb->len,
uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,