1 /* $FreeBSD: releng/10.2/sys/powerpc/powerpc/in_cksum.c 209975 2010-07-13 05:32:19Z nwhitehorn $ */
2 /* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
3
4 /*-
5 * Copyright (c) 1988, 1992, 1993
6 * The Regents of the University of California. All rights reserved.
7 * Copyright (c) 1996
8 * Matt Thomas <matt@3am-software.com>
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
39 */
40
41 #include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
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 static const u_int32_t in_masks[] = {
74 #if 0
75 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
76 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */
77 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */
78 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */
79 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */
80 #else
81 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
82 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */
83 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */
84 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */
85 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */
86 #endif
87 };
88
89 union l_util {
90 u_int16_t s[2];
91 u_int32_t l;
92 };
93 union q_util {
94 u_int16_t s[4];
95 u_int32_t l[2];
96 u_int64_t q;
97 };
98
99 static u_int64_t
100 in_cksumdata(const void *buf, int len)
101 {
102 const u_int32_t *lw = (const u_int32_t *) buf;
103 u_int64_t sum = 0;
104 u_int64_t prefilled;
105 int offset;
106 union q_util q_util;
107
108 if ((3 & (long) lw) == 0 && len == 20) {
109 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
110 REDUCE32;
111 return sum;
112 }
113
114 if ((offset = 3 & (long) lw) != 0) {
115 const u_int32_t *masks = in_masks + (offset << 2);
116 lw = (u_int32_t *) (((long) lw) - offset);
117 sum = *lw++ & masks[len >= 3 ? 3 : len];
118 len -= 4 - offset;
119 if (len <= 0) {
120 REDUCE32;
121 return sum;
122 }
123 }
124 #if 0
125 /*
126 * Force to cache line boundary.
127 */
128 offset = 32 - (0x1f & (long) lw);
129 if (offset < 32 && len > offset) {
130 len -= offset;
131 if (4 & offset) {
132 sum += (u_int64_t) lw[0];
133 lw += 1;
134 }
135 if (8 & offset) {
136 sum += (u_int64_t) lw[0] + lw[1];
137 lw += 2;
138 }
139 if (16 & offset) {
140 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
141 lw += 4;
142 }
143 }
144 #endif
145 /*
146 * access prefilling to start load of next cache line.
147 * then add current cache line
148 * save result of prefilling for loop iteration.
149 */
150 prefilled = lw[0];
151 while ((len -= 32) >= 4) {
152 u_int64_t prefilling = lw[8];
153 sum += prefilled + lw[1] + lw[2] + lw[3]
154 + lw[4] + lw[5] + lw[6] + lw[7];
155 lw += 8;
156 prefilled = prefilling;
157 }
158 if (len >= 0) {
159 sum += prefilled + lw[1] + lw[2] + lw[3]
160 + lw[4] + lw[5] + lw[6] + lw[7];
161 lw += 8;
162 } else {
163 len += 32;
164 }
165 while ((len -= 16) >= 0) {
166 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
167 lw += 4;
168 }
169 len += 16;
170 while ((len -= 4) >= 0) {
171 sum += (u_int64_t) *lw++;
172 }
173 len += 4;
174 if (len > 0)
175 sum += (u_int64_t) (in_masks[len] & *lw);
176 REDUCE32;
177 return sum;
178 }
179
180 u_short
181 in_addword(u_short a, u_short b)
182 {
183 u_int64_t sum = a + b;
184
185 ADDCARRY(sum);
186 return (sum);
187 }
188
189 u_short
190 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c)
191 {
192 u_int64_t sum;
193 union q_util q_util;
194 union l_util l_util;
195
196 sum = (u_int64_t) a + b + c;
197 REDUCE16;
198 return (sum);
199 }
200
201 u_short
202 in_cksum_skip(struct mbuf *m, int len, int skip)
203 {
204 u_int64_t sum = 0;
205 int mlen = 0;
206 int clen = 0;
207 caddr_t addr;
208 union q_util q_util;
209 union l_util l_util;
210
211 len -= skip;
212 for (; skip && m; m = m->m_next) {
213 if (m->m_len > skip) {
214 mlen = m->m_len - skip;
215 addr = mtod(m, caddr_t) + skip;
216 goto skip_start;
217 } else {
218 skip -= m->m_len;
219 }
220 }
221
222 for (; m && len; m = m->m_next) {
223 if (m->m_len == 0)
224 continue;
225 mlen = m->m_len;
226 addr = mtod(m, caddr_t);
227 skip_start:
228 if (len < mlen)
229 mlen = len;
230
231 if ((clen ^ (long) addr) & 1)
232 sum += in_cksumdata(addr, mlen) << 8;
233 else
234 sum += in_cksumdata(addr, mlen);
235
236 clen += mlen;
237 len -= mlen;
238 }
239 REDUCE16;
240 return (~sum & 0xffff);
241 }
242
243 u_int in_cksum_hdr(const struct ip *ip)
244 {
245 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip));
246 union q_util q_util;
247 union l_util l_util;
248 REDUCE16;
249 return (~sum & 0xffff);
250 }
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