FreeBSD/Linux Kernel Cross Reference
sys/arm/arm/in_cksum.c
1 /* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
2
3 /*-
4 * Copyright (c) 1988, 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 * Copyright (c) 1996
7 * Matt Thomas <matt@3am-software.com>
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
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.
24 *
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
35 * SUCH DAMAGE.
36 *
37 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
38 */
39
40 #include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
41 __FBSDID("$FreeBSD: src/sys/arm/arm/in_cksum.c,v 1.7 2006/07/18 00:07:05 cognet Exp $");
42
43 #include <sys/param.h>
44 #include <sys/mbuf.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>
50
51 /*
52 * Checksum routine for Internet Protocol family headers
53 * (Portable Alpha version).
54 *
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.
57 */
58
59 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
60 #define REDUCE32 \
61 { \
62 q_util.q = sum; \
63 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
64 }
65 #define REDUCE16 \
66 { \
67 q_util.q = sum; \
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]; \
70 ADDCARRY(sum); \
71 }
72
73 union l_util {
74 u_int16_t s[2];
75 u_int32_t l;
76 };
77 union q_util {
78 u_int16_t s[4];
79 u_int32_t l[2];
80 u_int64_t q;
81 };
82
83 u_short
84 in_addword(u_short a, u_short b)
85 {
86 u_int64_t sum = a + b;
87
88 ADDCARRY(sum);
89 return (sum);
90 }
91
92 static
93 uint64_t _do_cksum(void *addr, int len)
94 {
95 uint64_t sum;
96 union q_util q_util;
97
98 sum = do_cksum(addr, len);
99 REDUCE32;
100 return (sum);
101 }
102
103 u_short
104 in_cksum_skip(struct mbuf *m, int len, int skip)
105 {
106 u_int64_t sum = 0;
107 int mlen = 0;
108 int clen = 0;
109 caddr_t addr;
110 union q_util q_util;
111 union l_util l_util;
112
113 len -= 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;
118 goto skip_start;
119 } else {
120 skip -= m->m_len;
121 }
122 }
123
124 for (; m && len; m = m->m_next) {
125 if (m->m_len == 0)
126 continue;
127 mlen = m->m_len;
128 addr = mtod(m, caddr_t);
129 skip_start:
130 if (len < mlen)
131 mlen = len;
132
133 if ((clen ^ (int) addr) & 1)
134 sum += _do_cksum(addr, mlen) << 8;
135 else
136 sum += _do_cksum(addr, mlen);
137
138 clen += mlen;
139 len -= mlen;
140 }
141 REDUCE16;
142 return (~sum & 0xffff);
143 }
144
145 u_int in_cksum_hdr(const struct ip *ip)
146 {
147 u_int64_t sum = do_cksum(ip, sizeof(struct ip));
148 union q_util q_util;
149 union l_util l_util;
150 REDUCE16;
151 return (~sum & 0xffff);
152 }
153 Cache object: 32d20c1c26bee5a9052634769a9af9d2
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