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("$FreeBSD$");
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 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
75 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */
76 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */
77 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */
78 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */
79 };
80
81 union l_util {
82 u_int16_t s[2];
83 u_int32_t l;
84 };
85 union q_util {
86 u_int16_t s[4];
87 u_int32_t l[2];
88 u_int64_t q;
89 };
90
91 static u_int64_t
in_cksumdata(const void * buf,int len)92 in_cksumdata(const void *buf, int len)
93 {
94 const u_int32_t *lw = (const u_int32_t *) buf;
95 u_int64_t sum = 0;
96 u_int64_t prefilled;
97 int offset;
98 union q_util q_util;
99
100 if ((3 & (long) lw) == 0 && len == 20) {
101 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
102 REDUCE32;
103 return sum;
104 }
105
106 if ((offset = 3 & (long) lw) != 0) {
107 const u_int32_t *masks = in_masks + (offset << 2);
108 lw = (u_int32_t *) (((long) lw) - offset);
109 sum = *lw++ & masks[len >= 3 ? 3 : len];
110 len -= 4 - offset;
111 if (len <= 0) {
112 REDUCE32;
113 return sum;
114 }
115 }
116 #if 0
117 /*
118 * Force to cache line boundary.
119 */
120 offset = 32 - (0x1f & (long) lw);
121 if (offset < 32 && len > offset) {
122 len -= offset;
123 if (4 & offset) {
124 sum += (u_int64_t) lw[0];
125 lw += 1;
126 }
127 if (8 & offset) {
128 sum += (u_int64_t) lw[0] + lw[1];
129 lw += 2;
130 }
131 if (16 & offset) {
132 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
133 lw += 4;
134 }
135 }
136 #endif
137 /*
138 * access prefilling to start load of next cache line.
139 * then add current cache line
140 * save result of prefilling for loop iteration.
141 */
142 prefilled = lw[0];
143 while ((len -= 32) >= 4) {
144 u_int64_t prefilling = lw[8];
145 sum += prefilled + lw[1] + lw[2] + lw[3]
146 + lw[4] + lw[5] + lw[6] + lw[7];
147 lw += 8;
148 prefilled = prefilling;
149 }
150 if (len >= 0) {
151 sum += prefilled + lw[1] + lw[2] + lw[3]
152 + lw[4] + lw[5] + lw[6] + lw[7];
153 lw += 8;
154 } else {
155 len += 32;
156 }
157 while ((len -= 16) >= 0) {
158 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
159 lw += 4;
160 }
161 len += 16;
162 while ((len -= 4) >= 0) {
163 sum += (u_int64_t) *lw++;
164 }
165 len += 4;
166 if (len > 0)
167 sum += (u_int64_t) (in_masks[len] & *lw);
168 REDUCE32;
169 return sum;
170 }
171
172 u_short
in_addword(u_short a,u_short b)173 in_addword(u_short a, u_short b)
174 {
175 u_int64_t sum = a + b;
176
177 ADDCARRY(sum);
178 return (sum);
179 }
180
181 u_short
in_pseudo(u_int32_t a,u_int32_t b,u_int32_t c)182 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c)
183 {
184 u_int64_t sum;
185 union q_util q_util;
186 union l_util l_util;
187
188 sum = (u_int64_t) a + b + c;
189 REDUCE16;
190 return (sum);
191 }
192
193 u_short
in_cksum_skip(struct mbuf * m,int len,int skip)194 in_cksum_skip(struct mbuf *m, int len, int skip)
195 {
196 u_int64_t sum = 0;
197 int mlen = 0;
198 int clen = 0;
199 caddr_t addr;
200 union q_util q_util;
201 union l_util l_util;
202
203 len -= skip;
204 for (; skip && m; m = m->m_next) {
205 if (m->m_len > skip) {
206 mlen = m->m_len - skip;
207 addr = mtod(m, caddr_t) + skip;
208 goto skip_start;
209 } else {
210 skip -= m->m_len;
211 }
212 }
213
214 for (; m && len; m = m->m_next) {
215 if (m->m_len == 0)
216 continue;
217 mlen = m->m_len;
218 addr = mtod(m, caddr_t);
219 skip_start:
220 if (len < mlen)
221 mlen = len;
222 if ((clen ^ (long) addr) & 1)
223 sum += in_cksumdata(addr, mlen) << 8;
224 else
225 sum += in_cksumdata(addr, mlen);
226
227 clen += mlen;
228 len -= mlen;
229 }
230 REDUCE16;
231 return (~sum & 0xffff);
232 }
233
in_cksum_hdr(const struct ip * ip)234 u_int in_cksum_hdr(const struct ip *ip)
235 {
236 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip));
237 union q_util q_util;
238 union l_util l_util;
239 REDUCE16;
240 return (~sum & 0xffff);
241 }
242