1 /* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
4 * Copyright (c) 1988, 1992, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Matt Thomas <matt@3am-software.com>
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
40 #include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
41 __FBSDID("$FreeBSD$");
43 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <netinet/in_systm.h>
47 #include <netinet/in.h>
48 #include <netinet/ip.h>
49 #include <machine/in_cksum.h>
52 * Checksum routine for Internet Protocol family headers
53 * (Portable Alpha version).
55 * This routine is very heavily used in the network
56 * code and should be modified for each CPU to be as fast as possible.
59 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
63 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
68 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
69 sum = l_util.s[0] + l_util.s[1]; \
84 in_addword(u_short a, u_short b)
86 u_int64_t sum = a + b;
93 uint64_t _do_cksum(void *addr, int len)
98 sum = do_cksum(addr, len);
104 in_cksum_skip(struct mbuf *m, int len, int skip)
114 for (; skip && m; m = m->m_next) {
115 if (m->m_len > skip) {
116 mlen = m->m_len - skip;
117 addr = mtod(m, caddr_t) + skip;
124 for (; m && len; m = m->m_next) {
128 addr = mtod(m, caddr_t);
133 if ((clen ^ (int) addr) & 1)
134 sum += _do_cksum(addr, mlen) << 8;
136 sum += _do_cksum(addr, mlen);
142 return (~sum & 0xffff);
145 u_int in_cksum_hdr(const struct ip *ip)
147 u_int64_t sum = do_cksum(ip, sizeof(struct ip));
151 return (~sum & 0xffff);