1 /*-
2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the project nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 itojun Exp $
30 */
31
32 /*-
33 * Copyright (c) 1988, 1992, 1993
34 * The Regents of the University of California. All rights reserved.
35 *
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
38 * are met:
39 * 1. Redistributions of source code must retain the above copyright
40 * notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 * notice, this list of conditions and the following disclaimer in the
43 * documentation and/or other materials provided with the distribution.
44 * 4. Neither the name of the University nor the names of its contributors
45 * may be used to endorse or promote products derived from this software
46 * without specific prior written permission.
47 *
48 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58 * SUCH DAMAGE.
59 *
60 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
61 */
62
63 #include <sys/cdefs.h>
64 __FBSDID("$FreeBSD: releng/10.3/sys/netinet6/in6_cksum.c 272662 2014-10-06 17:08:19Z tuexen $");
65
66 #include <sys/param.h>
67 #include <sys/mbuf.h>
68 #include <sys/systm.h>
69 #include <netinet/in.h>
70 #include <netinet/ip6.h>
71 #include <netinet6/scope6_var.h>
72
73 /*
74 * Checksum routine for Internet Protocol family headers (Portable Version).
75 *
76 * This routine is very heavily used in the network
77 * code and should be modified for each CPU to be as fast as possible.
78 */
79
80 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
81 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; (void)ADDCARRY(sum);}
82
83 static int
84 _in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
85 {
86 int sum;
87 uint16_t scope, *w;
88 union {
89 u_int16_t phs[4];
90 struct {
91 u_int32_t ph_len;
92 u_int8_t ph_zero[3];
93 u_int8_t ph_nxt;
94 } __packed ph;
95 } uph;
96
97 sum = csum;
98
99 /*
100 * First create IP6 pseudo header and calculate a summary.
101 */
102 uph.ph.ph_len = htonl(len);
103 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
104 uph.ph.ph_nxt = nxt;
105
106 /* Payload length and upper layer identifier. */
107 sum += uph.phs[0]; sum += uph.phs[1];
108 sum += uph.phs[2]; sum += uph.phs[3];
109
110 /* IPv6 source address. */
111 scope = in6_getscope(&ip6->ip6_src);
112 w = (u_int16_t *)&ip6->ip6_src;
113 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
114 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
115 if (scope != 0)
116 sum -= scope;
117
118 /* IPv6 destination address. */
119 scope = in6_getscope(&ip6->ip6_dst);
120 w = (u_int16_t *)&ip6->ip6_dst;
121 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
122 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
123 if (scope != 0)
124 sum -= scope;
125
126 return (sum);
127 }
128
129 int
130 in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
131 {
132 int sum;
133 union {
134 u_int16_t s[2];
135 u_int32_t l;
136 } l_util;
137
138 sum = _in6_cksum_pseudo(ip6, len, nxt, csum);
139 REDUCE;
140 return (sum);
141 }
142
143 /*
144 * m MUST contain a contiguous IP6 header.
145 * off is an offset where TCP/UDP/ICMP6 header starts.
146 * len is a total length of a transport segment.
147 * (e.g. TCP header + TCP payload)
148 * cov is the number of bytes to be taken into account for the checksum
149 */
150 int
151 in6_cksum_partial(struct mbuf *m, u_int8_t nxt, u_int32_t off,
152 u_int32_t len, u_int32_t cov)
153 {
154 struct ip6_hdr *ip6;
155 u_int16_t *w, scope;
156 int byte_swapped, mlen;
157 int sum;
158 union {
159 u_int16_t phs[4];
160 struct {
161 u_int32_t ph_len;
162 u_int8_t ph_zero[3];
163 u_int8_t ph_nxt;
164 } __packed ph;
165 } uph;
166 union {
167 u_int8_t c[2];
168 u_int16_t s;
169 } s_util;
170 union {
171 u_int16_t s[2];
172 u_int32_t l;
173 } l_util;
174
175 /* Sanity check. */
176 KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+"
177 "len(%d)", __func__, m->m_pkthdr.len, off, len));
178
179 /*
180 * First create IP6 pseudo header and calculate a summary.
181 */
182 uph.ph.ph_len = htonl(len);
183 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
184 uph.ph.ph_nxt = nxt;
185
186 /* Payload length and upper layer identifier. */
187 sum = uph.phs[0]; sum += uph.phs[1];
188 sum += uph.phs[2]; sum += uph.phs[3];
189
190 ip6 = mtod(m, struct ip6_hdr *);
191
192 /* IPv6 source address. */
193 scope = in6_getscope(&ip6->ip6_src);
194 w = (u_int16_t *)&ip6->ip6_src;
195 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
196 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
197 if (scope != 0)
198 sum -= scope;
199
200 /* IPv6 destination address. */
201 scope = in6_getscope(&ip6->ip6_dst);
202 w = (u_int16_t *)&ip6->ip6_dst;
203 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
204 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
205 if (scope != 0)
206 sum -= scope;
207
208 /*
209 * Secondly calculate a summary of the first mbuf excluding offset.
210 */
211 while (off > 0) {
212 if (m->m_len <= off)
213 off -= m->m_len;
214 else
215 break;
216 m = m->m_next;
217 }
218 w = (u_int16_t *)(mtod(m, u_char *) + off);
219 mlen = m->m_len - off;
220 if (cov < mlen)
221 mlen = cov;
222 cov -= mlen;
223 /*
224 * Force to even boundary.
225 */
226 if ((1 & (long)w) && (mlen > 0)) {
227 REDUCE;
228 sum <<= 8;
229 s_util.c[0] = *(u_char *)w;
230 w = (u_int16_t *)((char *)w + 1);
231 mlen--;
232 byte_swapped = 1;
233 } else
234 byte_swapped = 0;
235
236 /*
237 * Unroll the loop to make overhead from
238 * branches &c small.
239 */
240 while ((mlen -= 32) >= 0) {
241 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
242 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
243 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
244 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
245 w += 16;
246 }
247 mlen += 32;
248 while ((mlen -= 8) >= 0) {
249 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
250 w += 4;
251 }
252 mlen += 8;
253 if (mlen == 0 && byte_swapped == 0)
254 goto next;
255 REDUCE;
256 while ((mlen -= 2) >= 0) {
257 sum += *w++;
258 }
259 if (byte_swapped) {
260 REDUCE;
261 sum <<= 8;
262 byte_swapped = 0;
263 if (mlen == -1) {
264 s_util.c[1] = *(char *)w;
265 sum += s_util.s;
266 mlen = 0;
267 } else
268 mlen = -1;
269 } else if (mlen == -1)
270 s_util.c[0] = *(char *)w;
271 next:
272 m = m->m_next;
273
274 /*
275 * Lastly calculate a summary of the rest of mbufs.
276 */
277
278 for (;m && cov; m = m->m_next) {
279 if (m->m_len == 0)
280 continue;
281 w = mtod(m, u_int16_t *);
282 if (mlen == -1) {
283 /*
284 * The first byte of this mbuf is the continuation
285 * of a word spanning between this mbuf and the
286 * last mbuf.
287 *
288 * s_util.c[0] is already saved when scanning previous
289 * mbuf.
290 */
291 s_util.c[1] = *(char *)w;
292 sum += s_util.s;
293 w = (u_int16_t *)((char *)w + 1);
294 mlen = m->m_len - 1;
295 cov--;
296 } else
297 mlen = m->m_len;
298 if (cov < mlen)
299 mlen = cov;
300 cov -= mlen;
301 /*
302 * Force to even boundary.
303 */
304 if ((1 & (long) w) && (mlen > 0)) {
305 REDUCE;
306 sum <<= 8;
307 s_util.c[0] = *(u_char *)w;
308 w = (u_int16_t *)((char *)w + 1);
309 mlen--;
310 byte_swapped = 1;
311 }
312 /*
313 * Unroll the loop to make overhead from
314 * branches &c small.
315 */
316 while ((mlen -= 32) >= 0) {
317 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
318 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
319 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
320 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
321 w += 16;
322 }
323 mlen += 32;
324 while ((mlen -= 8) >= 0) {
325 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
326 w += 4;
327 }
328 mlen += 8;
329 if (mlen == 0 && byte_swapped == 0)
330 continue;
331 REDUCE;
332 while ((mlen -= 2) >= 0) {
333 sum += *w++;
334 }
335 if (byte_swapped) {
336 REDUCE;
337 sum <<= 8;
338 byte_swapped = 0;
339 if (mlen == -1) {
340 s_util.c[1] = *(char *)w;
341 sum += s_util.s;
342 mlen = 0;
343 } else
344 mlen = -1;
345 } else if (mlen == -1)
346 s_util.c[0] = *(char *)w;
347 }
348 if (cov)
349 panic("in6_cksum: out of data");
350 if (mlen == -1) {
351 /* The last mbuf has odd # of bytes. Follow the
352 standard (the odd byte may be shifted left by 8 bits
353 or not as determined by endian-ness of the machine) */
354 s_util.c[1] = 0;
355 sum += s_util.s;
356 }
357 REDUCE;
358 return (~sum & 0xffff);
359 }
360
361 int
362 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
363 {
364 return (in6_cksum_partial(m, nxt, off, len, len));
365 }
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