1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
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. Neither the name of the project nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 itojun Exp $
32 */
33
34 /*-
35 * Copyright (c) 1988, 1992, 1993
36 * The Regents of the University of California. All rights reserved.
37 *
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
40 * are met:
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 * notice, this list of conditions and the following disclaimer in the
45 * documentation and/or other materials provided with the distribution.
46 * 3. Neither the name of the University nor the names of its contributors
47 * may be used to endorse or promote products derived from this software
48 * without specific prior written permission.
49 *
50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60 * SUCH DAMAGE.
61 *
62 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
63 */
64
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
67
68 #include <sys/param.h>
69 #include <sys/mbuf.h>
70 #include <sys/systm.h>
71 #include <netinet/in.h>
72 #include <netinet/ip6.h>
73 #include <netinet6/scope6_var.h>
74
75 /*
76 * Checksum routine for Internet Protocol family headers (Portable Version).
77 *
78 * This routine is very heavily used in the network
79 * code and should be modified for each CPU to be as fast as possible.
80 */
81
82 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
83 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; (void)ADDCARRY(sum);}
84
85 static int
86 _in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
87 {
88 int sum;
89 uint16_t scope, *w;
90 union {
91 u_int16_t phs[4];
92 struct {
93 u_int32_t ph_len;
94 u_int8_t ph_zero[3];
95 u_int8_t ph_nxt;
96 } __packed ph;
97 } uph;
98
99 sum = csum;
100
101 /*
102 * First create IP6 pseudo header and calculate a summary.
103 */
104 uph.ph.ph_len = htonl(len);
105 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
106 uph.ph.ph_nxt = nxt;
107
108 /* Payload length and upper layer identifier. */
109 sum += uph.phs[0]; sum += uph.phs[1];
110 sum += uph.phs[2]; sum += uph.phs[3];
111
112 /* IPv6 source address. */
113 scope = in6_getscope(&ip6->ip6_src);
114 w = (u_int16_t *)&ip6->ip6_src;
115 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
116 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
117 if (scope != 0)
118 sum -= scope;
119
120 /* IPv6 destination address. */
121 scope = in6_getscope(&ip6->ip6_dst);
122 w = (u_int16_t *)&ip6->ip6_dst;
123 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
124 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
125 if (scope != 0)
126 sum -= scope;
127
128 return (sum);
129 }
130
131 int
132 in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
133 {
134 int sum;
135 union {
136 u_int16_t s[2];
137 u_int32_t l;
138 } l_util;
139
140 sum = _in6_cksum_pseudo(ip6, len, nxt, csum);
141 REDUCE;
142 return (sum);
143 }
144
145 /*
146 * m MUST contain a contiguous IP6 header.
147 * off is an offset where TCP/UDP/ICMP6 header starts.
148 * len is a total length of a transport segment.
149 * (e.g. TCP header + TCP payload)
150 * cov is the number of bytes to be taken into account for the checksum
151 */
152 int
153 in6_cksum_partial(struct mbuf *m, u_int8_t nxt, u_int32_t off,
154 u_int32_t len, u_int32_t cov)
155 {
156 struct ip6_hdr *ip6;
157 u_int16_t *w, scope;
158 int byte_swapped, mlen;
159 int sum;
160 union {
161 u_int16_t phs[4];
162 struct {
163 u_int32_t ph_len;
164 u_int8_t ph_zero[3];
165 u_int8_t ph_nxt;
166 } __packed ph;
167 } uph;
168 union {
169 u_int8_t c[2];
170 u_int16_t s;
171 } s_util;
172 union {
173 u_int16_t s[2];
174 u_int32_t l;
175 } l_util;
176
177 /* Sanity check. */
178 KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+"
179 "len(%d)", __func__, m->m_pkthdr.len, off, len));
180
181 /*
182 * First create IP6 pseudo header and calculate a summary.
183 */
184 uph.ph.ph_len = htonl(len);
185 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
186 uph.ph.ph_nxt = nxt;
187
188 /* Payload length and upper layer identifier. */
189 sum = uph.phs[0]; sum += uph.phs[1];
190 sum += uph.phs[2]; sum += uph.phs[3];
191
192 ip6 = mtod(m, struct ip6_hdr *);
193
194 /* IPv6 source address. */
195 scope = in6_getscope(&ip6->ip6_src);
196 w = (u_int16_t *)&ip6->ip6_src;
197 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
198 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
199 if (scope != 0)
200 sum -= scope;
201
202 /* IPv6 destination address. */
203 scope = in6_getscope(&ip6->ip6_dst);
204 w = (u_int16_t *)&ip6->ip6_dst;
205 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
206 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
207 if (scope != 0)
208 sum -= scope;
209
210 /*
211 * Secondly calculate a summary of the first mbuf excluding offset.
212 */
213 while (off > 0) {
214 if (m->m_len <= off)
215 off -= m->m_len;
216 else
217 break;
218 m = m->m_next;
219 }
220 w = (u_int16_t *)(mtod(m, u_char *) + off);
221 mlen = m->m_len - off;
222 if (cov < mlen)
223 mlen = cov;
224 cov -= mlen;
225 /*
226 * Force to even boundary.
227 */
228 if ((1 & (long)w) && (mlen > 0)) {
229 REDUCE;
230 sum <<= 8;
231 s_util.c[0] = *(u_char *)w;
232 w = (u_int16_t *)((char *)w + 1);
233 mlen--;
234 byte_swapped = 1;
235 } else
236 byte_swapped = 0;
237
238 /*
239 * Unroll the loop to make overhead from
240 * branches &c small.
241 */
242 while ((mlen -= 32) >= 0) {
243 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
244 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
245 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
246 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
247 w += 16;
248 }
249 mlen += 32;
250 while ((mlen -= 8) >= 0) {
251 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
252 w += 4;
253 }
254 mlen += 8;
255 if (mlen == 0 && byte_swapped == 0)
256 goto next;
257 REDUCE;
258 while ((mlen -= 2) >= 0) {
259 sum += *w++;
260 }
261 if (byte_swapped) {
262 REDUCE;
263 sum <<= 8;
264 byte_swapped = 0;
265 if (mlen == -1) {
266 s_util.c[1] = *(char *)w;
267 sum += s_util.s;
268 mlen = 0;
269 } else
270 mlen = -1;
271 } else if (mlen == -1)
272 s_util.c[0] = *(char *)w;
273 next:
274 m = m->m_next;
275
276 /*
277 * Lastly calculate a summary of the rest of mbufs.
278 */
279
280 for (;m && cov; m = m->m_next) {
281 if (m->m_len == 0)
282 continue;
283 w = mtod(m, u_int16_t *);
284 if (mlen == -1) {
285 /*
286 * The first byte of this mbuf is the continuation
287 * of a word spanning between this mbuf and the
288 * last mbuf.
289 *
290 * s_util.c[0] is already saved when scanning previous
291 * mbuf.
292 */
293 s_util.c[1] = *(char *)w;
294 sum += s_util.s;
295 w = (u_int16_t *)((char *)w + 1);
296 mlen = m->m_len - 1;
297 cov--;
298 } else
299 mlen = m->m_len;
300 if (cov < mlen)
301 mlen = cov;
302 cov -= mlen;
303 /*
304 * Force to even boundary.
305 */
306 if ((1 & (long) w) && (mlen > 0)) {
307 REDUCE;
308 sum <<= 8;
309 s_util.c[0] = *(u_char *)w;
310 w = (u_int16_t *)((char *)w + 1);
311 mlen--;
312 byte_swapped = 1;
313 }
314 /*
315 * Unroll the loop to make overhead from
316 * branches &c small.
317 */
318 while ((mlen -= 32) >= 0) {
319 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
320 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
321 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
322 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
323 w += 16;
324 }
325 mlen += 32;
326 while ((mlen -= 8) >= 0) {
327 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
328 w += 4;
329 }
330 mlen += 8;
331 if (mlen == 0 && byte_swapped == 0)
332 continue;
333 REDUCE;
334 while ((mlen -= 2) >= 0) {
335 sum += *w++;
336 }
337 if (byte_swapped) {
338 REDUCE;
339 sum <<= 8;
340 byte_swapped = 0;
341 if (mlen == -1) {
342 s_util.c[1] = *(char *)w;
343 sum += s_util.s;
344 mlen = 0;
345 } else
346 mlen = -1;
347 } else if (mlen == -1)
348 s_util.c[0] = *(char *)w;
349 }
350 if (cov)
351 panic("in6_cksum: out of data");
352 if (mlen == -1) {
353 /* The last mbuf has odd # of bytes. Follow the
354 standard (the odd byte may be shifted left by 8 bits
355 or not as determined by endian-ness of the machine) */
356 s_util.c[1] = 0;
357 sum += s_util.s;
358 }
359 REDUCE;
360 return (~sum & 0xffff);
361 }
362
363 int
364 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
365 {
366 return (in6_cksum_partial(m, nxt, off, len, len));
367 }
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