sys/netinet/tcp_input.c

582 	int off0;
617 	off0 = *offp;
636 		th = (struct tcphdr *)((caddr_t)ip6 + off0);
637 		tlen = sizeof(*ip6) + ntohs(ip6->ip6_plen) - off0;
646 			th->th_sum = in6_cksum(m, IPPROTO_TCP, off0, tlen);
676 		if (off0 > sizeof (struct ip)) {
678 			off0 = sizeof(struct ip);
688 		th = (struct tcphdr *)((caddr_t)ip + off0);
689 		tlen = ntohs(ip->ip_len) - off0;
707 			len = off0 + tlen;
719 			ip->ip_hl = off0 >> 2;
742 			IP6_EXTHDR_CHECK(m, off0, off, IPPROTO_DONE);
744 			th = (struct tcphdr *)((caddr_t)ip6 + off0);
759 				th = (struct tcphdr *)((caddr_t)ip + off0);
776 	drop_hdrlen = off0 + off;