1 /* $OpenBSD: in4_cksum.c,v 1.7 2003/06/02 23:28:13 millert Exp $ */
2 /* $KAME: in4_cksum.c,v 1.10 2001/11/30 10:06:15 itojun Exp $ */
3 /* $NetBSD: in_cksum.c,v 1.13 1996/10/13 02:03:03 christos Exp $ */
4
5 /*-
6 * SPDX-License-Identifier: BSD-3-Clause
7 *
8 * Copyright (C) 1999 WIDE Project.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the project nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 /*
37 * Copyright (c) 1988, 1992, 1993
38 * The Regents of the University of California. All rights reserved.
39 *
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
42 * are met:
43 * 1. Redistributions of source code must retain the above copyright
44 * notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 * notice, this list of conditions and the following disclaimer in the
47 * documentation and/or other materials provided with the distribution.
48 * 3. Neither the name of the University nor the names of its contributors
49 * may be used to endorse or promote products derived from this software
50 * without specific prior written permission.
51 *
52 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62 * SUCH DAMAGE.
63 */
64
65 #include <sys/param.h>
66 #include <sys/systm.h>
67 #include <sys/mbuf.h>
68
69 #include <netinet/in.h>
70 #include <netinet/in_systm.h>
71 #include <netinet/ip.h>
72 #include <netinet/ip_var.h>
73
74 #include <machine/in_cksum.h>
75
76 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
77 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; (void)ADDCARRY(sum);}
78
79 int in4_cksum(struct mbuf *, u_int8_t, int, int);
80
81 int
in4_cksum(struct mbuf * m,u_int8_t nxt,int off,int len)82 in4_cksum(struct mbuf *m, u_int8_t nxt, int off, int len)
83 {
84 union {
85 struct ipovly ipov;
86 u_int16_t w[10];
87 } u;
88 union {
89 u_int16_t s[2];
90 u_int32_t l;
91 } l_util;
92
93 u_int16_t *w;
94 int psum;
95 int sum = 0;
96
97 if (nxt != 0) {
98 /* pseudo header */
99 if (off < sizeof(struct ipovly))
100 panic("in4_cksum: offset too short");
101 if (m->m_len < sizeof(struct ip))
102 panic("in4_cksum: bad mbuf chain");
103 bzero(&u.ipov, sizeof(u.ipov));
104 u.ipov.ih_len = htons(len);
105 u.ipov.ih_pr = nxt;
106 u.ipov.ih_src = mtod(m, struct ip *)->ip_src;
107 u.ipov.ih_dst = mtod(m, struct ip *)->ip_dst;
108 w = u.w;
109 /* assumes sizeof(ipov) == 20 */
110 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4];
111 sum += w[5]; sum += w[6]; sum += w[7]; sum += w[8]; sum += w[9];
112 }
113
114 psum = in_cksum_skip(m, len + off, off);
115 psum = ~psum & 0xffff;
116 sum += psum;
117 REDUCE;
118 return (~sum & 0xffff);
119 }
120