2 /* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
5 * SPDX-License-Identifier: BSD-4-Clause
7 * Copyright (c) 1988, 1992, 1993
8 * The Regents of the University of California. All rights reserved.
10 * Matt Thomas <matt@3am-software.com>
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
43 #include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
45 #include <sys/endian.h>
46 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <netinet/in_systm.h>
50 #include <netinet/in.h>
51 #include <netinet/ip.h>
52 #include <machine/in_cksum.h>
55 * Checksum routine for Internet Protocol family headers
56 * (Portable Alpha version).
58 * This routine is very heavily used in the network
59 * code and should be modified for each CPU to be as fast as possible.
62 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
66 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
71 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
72 sum = l_util.s[0] + l_util.s[1]; \
76 static const u_int32_t in_masks[] = {
77 #if _BYTE_ORDER == _LITTLE_ENDIAN
78 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
79 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */
80 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */
81 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */
82 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */
84 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
85 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */
86 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */
87 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */
88 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */
103 in_cksumdata(const void *buf, int len)
105 const u_int32_t *lw = (const u_int32_t *) buf;
111 if ((3 & (long) lw) == 0 && len == 20) {
112 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
117 if ((offset = 3 & (long) lw) != 0) {
118 const u_int32_t *masks = in_masks + (offset << 2);
119 lw = (u_int32_t *) (((long) lw) - offset);
120 sum = *lw++ & masks[len >= 3 ? 3 : len];
129 * Force to cache line boundary.
131 offset = 32 - (0x1f & (long) lw);
132 if (offset < 32 && len > offset) {
135 sum += (u_int64_t) lw[0];
139 sum += (u_int64_t) lw[0] + lw[1];
143 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
149 * access prefilling to start load of next cache line.
150 * then add current cache line
151 * save result of prefilling for loop iteration.
154 while ((len -= 32) >= 4) {
155 u_int64_t prefilling = lw[8];
156 sum += prefilled + lw[1] + lw[2] + lw[3]
157 + lw[4] + lw[5] + lw[6] + lw[7];
159 prefilled = prefilling;
162 sum += prefilled + lw[1] + lw[2] + lw[3]
163 + lw[4] + lw[5] + lw[6] + lw[7];
168 while ((len -= 16) >= 0) {
169 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
173 while ((len -= 4) >= 0) {
174 sum += (u_int64_t) *lw++;
178 sum += (u_int64_t) (in_masks[len] & *lw);
184 in_addword(u_short a, u_short b)
186 u_int64_t sum = a + b;
193 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c)
199 sum = (u_int64_t) a + b + c;
205 in_cksum_skip(struct mbuf *m, int len, int skip)
215 for (; skip && m; m = m->m_next) {
216 if (m->m_len > skip) {
217 mlen = m->m_len - skip;
218 addr = mtod(m, caddr_t) + skip;
225 for (; m && len; m = m->m_next) {
229 addr = mtod(m, caddr_t);
234 if ((clen ^ (long) addr) & 1)
235 sum += in_cksumdata(addr, mlen) << 8;
237 sum += in_cksumdata(addr, mlen);
243 return (~sum & 0xffff);
246 u_int in_cksum_hdr(const struct ip *ip)
248 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip));
252 return (~sum & 0xffff);