1 /*-
2 * Copyright (c) 1988, 1992, 1993
3 * The Regents of the University of California. All rights reserved.
4 * Copyright (c) 1996
5 * Matt Thomas <matt@3am-software.com>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
36 */
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <sys/param.h>
42 #include <sys/mbuf.h>
43 #include <sys/systm.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/in.h>
46 #include <netinet/ip.h>
47 #include <machine/in_cksum.h>
48
49 /*
50 * Checksum routine for Internet Protocol family headers
51 * (Portable Alpha version).
52 *
53 * This routine is very heavily used in the network
54 * code and should be modified for each CPU to be as fast as possible.
55 */
56
57 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
58 #define REDUCE32 \
59 { \
60 q_util.q = sum; \
61 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
62 }
63 #define REDUCE16 \
64 { \
65 q_util.q = sum; \
66 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
67 sum = l_util.s[0] + l_util.s[1]; \
68 ADDCARRY(sum); \
69 }
70
71 static const u_int32_t in_masks[] = {
72 #if _BYTE_ORDER == _LITTLE_ENDIAN
73 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
74 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */
75 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */
76 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */
77 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */
78 #else
79 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
80 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */
81 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */
82 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */
83 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */
84 #endif
85 };
86
87 union l_util {
88 u_int16_t s[2];
89 u_int32_t l;
90 };
91 union q_util {
92 u_int16_t s[4];
93 u_int32_t l[2];
94 u_int64_t q;
95 };
96
97 static u_int64_t
98 in_cksumdata(const void *buf, int len)
99 {
100 const u_int32_t *lw = (const u_int32_t *) buf;
101 u_int64_t sum = 0;
102 u_int64_t prefilled;
103 int offset;
104 union q_util q_util;
105
106 if ((3 & (long) lw) == 0 && len == 20) {
107 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
108 REDUCE32;
109 return sum;
110 }
111
112 if ((offset = 3 & (long) lw) != 0) {
113 const u_int32_t *masks = in_masks + (offset << 2);
114 lw = (u_int32_t *) (((long) lw) - offset);
115 sum = *lw++ & masks[len >= 3 ? 3 : len];
116 len -= 4 - offset;
117 if (len <= 0) {
118 REDUCE32;
119 return sum;
120 }
121 }
122 #if 0
123 /*
124 * Force to cache line boundary.
125 */
126 offset = 32 - (0x1f & (long) lw);
127 if (offset < 32 && len > offset) {
128 len -= offset;
129 if (4 & offset) {
130 sum += (u_int64_t) lw[0];
131 lw += 1;
132 }
133 if (8 & offset) {
134 sum += (u_int64_t) lw[0] + lw[1];
135 lw += 2;
136 }
137 if (16 & offset) {
138 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
139 lw += 4;
140 }
141 }
142 #endif
143 /*
144 * access prefilling to start load of next cache line.
145 * then add current cache line
146 * save result of prefilling for loop iteration.
147 */
148 prefilled = lw[0];
149 while ((len -= 32) >= 4) {
150 u_int64_t prefilling = lw[8];
151 sum += prefilled + lw[1] + lw[2] + lw[3]
152 + lw[4] + lw[5] + lw[6] + lw[7];
153 lw += 8;
154 prefilled = prefilling;
155 }
156 if (len >= 0) {
157 sum += prefilled + lw[1] + lw[2] + lw[3]
158 + lw[4] + lw[5] + lw[6] + lw[7];
159 lw += 8;
160 } else {
161 len += 32;
162 }
163 while ((len -= 16) >= 0) {
164 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
165 lw += 4;
166 }
167 len += 16;
168 while ((len -= 4) >= 0) {
169 sum += (u_int64_t) *lw++;
170 }
171 len += 4;
172 if (len > 0)
173 sum += (u_int64_t) (in_masks[len] & *lw);
174 REDUCE32;
175 return sum;
176 }
177
178 u_short
179 in_addword(u_short a, u_short b)
180 {
181 u_int64_t sum = a + b;
182
183 ADDCARRY(sum);
184 return (sum);
185 }
186
187 u_short
188 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c)
189 {
190 u_int64_t sum;
191 union q_util q_util;
192 union l_util l_util;
193
194 sum = (u_int64_t) a + b + c;
195 REDUCE16;
196 return (sum);
197 }
198
199 u_short
200 in_cksum_skip(struct mbuf *m, int len, int skip)
201 {
202 u_int64_t sum = 0;
203 int mlen = 0;
204 int clen = 0;
205 caddr_t addr;
206 union q_util q_util;
207 union l_util l_util;
208
209 len -= skip;
210 for (; skip && m; m = m->m_next) {
211 if (m->m_len > skip) {
212 mlen = m->m_len - skip;
213 addr = mtod(m, caddr_t) + skip;
214 goto skip_start;
215 } else {
216 skip -= m->m_len;
217 }
218 }
219
220 for (; m && len; m = m->m_next) {
221 if (m->m_len == 0)
222 continue;
223 mlen = m->m_len;
224 addr = mtod(m, caddr_t);
225 skip_start:
226 if (len < mlen)
227 mlen = len;
228
229 if ((clen ^ (uintptr_t) addr) & 1)
230 sum += in_cksumdata(addr, mlen) << 8;
231 else
232 sum += in_cksumdata(addr, mlen);
233
234 clen += mlen;
235 len -= mlen;
236 }
237 REDUCE16;
238 return (~sum & 0xffff);
239 }
240
241 u_int in_cksum_hdr(const struct ip *ip)
242 {
243 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip));
244 union q_util q_util;
245 union l_util l_util;
246 REDUCE16;
247 return (~sum & 0xffff);
248 }
Cache object: 3285ebd8724b742441cb97beb7dced8b
|