1 /* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-4-Clause
5 *
6 * Copyright (c) 1988, 1992, 1993
7 * The Regents of the University of California. All rights reserved.
8 * Copyright (c) 1996
9 * Matt Thomas <matt@3am-software.com>
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. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
40 */
41
42 #include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
43 __FBSDID("$FreeBSD: releng/12.0/sys/riscv/riscv/in_cksum.c 325966 2017-11-18 14:26:50Z pfg $");
44
45 #include <sys/param.h>
46 #include <sys/mbuf.h>
47 #include <sys/systm.h>
48 #include <netinet/in_systm.h>
49 #include <netinet/in.h>
50 #include <netinet/ip.h>
51 #include <machine/in_cksum.h>
52
53 /*
54 * Checksum routine for Internet Protocol family headers
55 * (Portable Alpha version).
56 *
57 * This routine is very heavily used in the network
58 * code and should be modified for each CPU to be as fast as possible.
59 */
60
61 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
62 #define REDUCE32 \
63 { \
64 q_util.q = sum; \
65 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
66 }
67 #define REDUCE16 \
68 { \
69 q_util.q = sum; \
70 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
71 sum = l_util.s[0] + l_util.s[1]; \
72 ADDCARRY(sum); \
73 }
74
75 static const u_int32_t in_masks[] = {
76 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
77 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */
78 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */
79 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */
80 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */
81 };
82
83 union l_util {
84 u_int16_t s[2];
85 u_int32_t l;
86 };
87 union q_util {
88 u_int16_t s[4];
89 u_int32_t l[2];
90 u_int64_t q;
91 };
92
93 static u_int64_t
94 in_cksumdata(const void *buf, int len)
95 {
96 const u_int32_t *lw = (const u_int32_t *) buf;
97 u_int64_t sum = 0;
98 u_int64_t prefilled;
99 int offset;
100 union q_util q_util;
101
102 if ((3 & (long) lw) == 0 && len == 20) {
103 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
104 REDUCE32;
105 return sum;
106 }
107
108 if ((offset = 3 & (long) lw) != 0) {
109 const u_int32_t *masks = in_masks + (offset << 2);
110 lw = (u_int32_t *) (((long) lw) - offset);
111 sum = *lw++ & masks[len >= 3 ? 3 : len];
112 len -= 4 - offset;
113 if (len <= 0) {
114 REDUCE32;
115 return sum;
116 }
117 }
118 #if 0
119 /*
120 * Force to cache line boundary.
121 */
122 offset = 32 - (0x1f & (long) lw);
123 if (offset < 32 && len > offset) {
124 len -= offset;
125 if (4 & offset) {
126 sum += (u_int64_t) lw[0];
127 lw += 1;
128 }
129 if (8 & offset) {
130 sum += (u_int64_t) lw[0] + lw[1];
131 lw += 2;
132 }
133 if (16 & offset) {
134 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
135 lw += 4;
136 }
137 }
138 #endif
139 /*
140 * access prefilling to start load of next cache line.
141 * then add current cache line
142 * save result of prefilling for loop iteration.
143 */
144 prefilled = lw[0];
145 while ((len -= 32) >= 4) {
146 u_int64_t prefilling = lw[8];
147 sum += prefilled + lw[1] + lw[2] + lw[3]
148 + lw[4] + lw[5] + lw[6] + lw[7];
149 lw += 8;
150 prefilled = prefilling;
151 }
152 if (len >= 0) {
153 sum += prefilled + lw[1] + lw[2] + lw[3]
154 + lw[4] + lw[5] + lw[6] + lw[7];
155 lw += 8;
156 } else {
157 len += 32;
158 }
159 while ((len -= 16) >= 0) {
160 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
161 lw += 4;
162 }
163 len += 16;
164 while ((len -= 4) >= 0) {
165 sum += (u_int64_t) *lw++;
166 }
167 len += 4;
168 if (len > 0)
169 sum += (u_int64_t) (in_masks[len] & *lw);
170 REDUCE32;
171 return sum;
172 }
173
174 u_short
175 in_addword(u_short a, u_short b)
176 {
177 u_int64_t sum = a + b;
178
179 ADDCARRY(sum);
180 return (sum);
181 }
182
183 u_short
184 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c)
185 {
186 u_int64_t sum;
187 union q_util q_util;
188 union l_util l_util;
189
190 sum = (u_int64_t) a + b + c;
191 REDUCE16;
192 return (sum);
193 }
194
195 u_short
196 in_cksum_skip(struct mbuf *m, int len, int skip)
197 {
198 u_int64_t sum = 0;
199 int mlen = 0;
200 int clen = 0;
201 caddr_t addr;
202 union q_util q_util;
203 union l_util l_util;
204
205 len -= skip;
206 for (; skip && m; m = m->m_next) {
207 if (m->m_len > skip) {
208 mlen = m->m_len - skip;
209 addr = mtod(m, caddr_t) + skip;
210 goto skip_start;
211 } else {
212 skip -= m->m_len;
213 }
214 }
215
216 for (; m && len; m = m->m_next) {
217 if (m->m_len == 0)
218 continue;
219 mlen = m->m_len;
220 addr = mtod(m, caddr_t);
221 skip_start:
222 if (len < mlen)
223 mlen = len;
224 if ((clen ^ (long) addr) & 1)
225 sum += in_cksumdata(addr, mlen) << 8;
226 else
227 sum += in_cksumdata(addr, mlen);
228
229 clen += mlen;
230 len -= mlen;
231 }
232 REDUCE16;
233 return (~sum & 0xffff);
234 }
235
236 u_int in_cksum_hdr(const struct ip *ip)
237 {
238 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip));
239 union q_util q_util;
240 union l_util l_util;
241 REDUCE16;
242 return (~sum & 0xffff);
243 }
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