- if (nf_ip_checksum(oldskb, hook, iph->ihl * 4, IPPROTO_TCP))
+ tcplen = oldskb->len - iph->ihl * 4;
+ if (((hook != NF_IP_LOCAL_IN && oldskb->ip_summed != CHECKSUM_HW) ||
+ (hook == NF_IP_LOCAL_IN &&
+ oldskb->ip_summed != CHECKSUM_UNNECESSARY)) &&
+ csum_tcpudp_magic(iph->saddr, iph->daddr, tcplen, IPPROTO_TCP,
+ oldskb->ip_summed == CHECKSUM_HW ? oldskb->csum :
+ skb_checksum(oldskb, iph->ihl * 4, tcplen, 0)))