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("$FreeBSD$");
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 */
149 int
150 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
151 {
152 struct ip6_hdr *ip6;
153 u_int16_t *w, scope;
154 int byte_swapped, mlen;
155 int sum;
156 union {
157 u_int16_t phs[4];
158 struct {
159 u_int32_t ph_len;
160 u_int8_t ph_zero[3];
161 u_int8_t ph_nxt;
162 } __packed ph;
163 } uph;
164 union {
165 u_int8_t c[2];
166 u_int16_t s;
167 } s_util;
168 union {
169 u_int16_t s[2];
170 u_int32_t l;
171 } l_util;
172
173 /* Sanity check. */
174 KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+"
175 "len(%d)", __func__, m->m_pkthdr.len, off, len));
176
177 /*
178 * First create IP6 pseudo header and calculate a summary.
179 */
180 uph.ph.ph_len = htonl(len);
181 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
182 uph.ph.ph_nxt = nxt;
183
184 /* Payload length and upper layer identifier. */
185 sum = uph.phs[0]; sum += uph.phs[1];
186 sum += uph.phs[2]; sum += uph.phs[3];
187
188 ip6 = mtod(m, struct ip6_hdr *);
189
190 /* IPv6 source address. */
191 scope = in6_getscope(&ip6->ip6_src);
192 w = (u_int16_t *)&ip6->ip6_src;
193 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
194 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
195 if (scope != 0)
196 sum -= scope;
197
198 /* IPv6 destination address. */
199 scope = in6_getscope(&ip6->ip6_dst);
200 w = (u_int16_t *)&ip6->ip6_dst;
201 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
202 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
203 if (scope != 0)
204 sum -= scope;
205
206 /*
207 * Secondly calculate a summary of the first mbuf excluding offset.
208 */
209 while (off > 0) {
210 if (m->m_len <= off)
211 off -= m->m_len;
212 else
213 break;
214 m = m->m_next;
215 }
216 w = (u_int16_t *)(mtod(m, u_char *) + off);
217 mlen = m->m_len - off;
218 if (len < mlen)
219 mlen = len;
220 len -= mlen;
221 /*
222 * Force to even boundary.
223 */
224 if ((1 & (long)w) && (mlen > 0)) {
225 REDUCE;
226 sum <<= 8;
227 s_util.c[0] = *(u_char *)w;
228 w = (u_int16_t *)((char *)w + 1);
229 mlen--;
230 byte_swapped = 1;
231 } else
232 byte_swapped = 0;
233
234 /*
235 * Unroll the loop to make overhead from
236 * branches &c small.
237 */
238 while ((mlen -= 32) >= 0) {
239 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
240 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
241 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
242 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
243 w += 16;
244 }
245 mlen += 32;
246 while ((mlen -= 8) >= 0) {
247 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
248 w += 4;
249 }
250 mlen += 8;
251 if (mlen == 0 && byte_swapped == 0)
252 goto next;
253 REDUCE;
254 while ((mlen -= 2) >= 0) {
255 sum += *w++;
256 }
257 if (byte_swapped) {
258 REDUCE;
259 sum <<= 8;
260 byte_swapped = 0;
261 if (mlen == -1) {
262 s_util.c[1] = *(char *)w;
263 sum += s_util.s;
264 mlen = 0;
265 } else
266 mlen = -1;
267 } else if (mlen == -1)
268 s_util.c[0] = *(char *)w;
269 next:
270 m = m->m_next;
271
272 /*
273 * Lastly calculate a summary of the rest of mbufs.
274 */
275
276 for (;m && len; m = m->m_next) {
277 if (m->m_len == 0)
278 continue;
279 w = mtod(m, u_int16_t *);
280 if (mlen == -1) {
281 /*
282 * The first byte of this mbuf is the continuation
283 * of a word spanning between this mbuf and the
284 * last mbuf.
285 *
286 * s_util.c[0] is already saved when scanning previous
287 * mbuf.
288 */
289 s_util.c[1] = *(char *)w;
290 sum += s_util.s;
291 w = (u_int16_t *)((char *)w + 1);
292 mlen = m->m_len - 1;
293 len--;
294 } else
295 mlen = m->m_len;
296 if (len < mlen)
297 mlen = len;
298 len -= mlen;
299 /*
300 * Force to even boundary.
301 */
302 if ((1 & (long) w) && (mlen > 0)) {
303 REDUCE;
304 sum <<= 8;
305 s_util.c[0] = *(u_char *)w;
306 w = (u_int16_t *)((char *)w + 1);
307 mlen--;
308 byte_swapped = 1;
309 }
310 /*
311 * Unroll the loop to make overhead from
312 * branches &c small.
313 */
314 while ((mlen -= 32) >= 0) {
315 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
316 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
317 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
318 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
319 w += 16;
320 }
321 mlen += 32;
322 while ((mlen -= 8) >= 0) {
323 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
324 w += 4;
325 }
326 mlen += 8;
327 if (mlen == 0 && byte_swapped == 0)
328 continue;
329 REDUCE;
330 while ((mlen -= 2) >= 0) {
331 sum += *w++;
332 }
333 if (byte_swapped) {
334 REDUCE;
335 sum <<= 8;
336 byte_swapped = 0;
337 if (mlen == -1) {
338 s_util.c[1] = *(char *)w;
339 sum += s_util.s;
340 mlen = 0;
341 } else
342 mlen = -1;
343 } else if (mlen == -1)
344 s_util.c[0] = *(char *)w;
345 }
346 if (len)
347 panic("in6_cksum: out of data");
348 if (mlen == -1) {
349 /* The last mbuf has odd # of bytes. Follow the
350 standard (the odd byte may be shifted left by 8 bits
351 or not as determined by endian-ness of the machine) */
352 s_util.c[1] = 0;
353 sum += s_util.s;
354 }
355 REDUCE;
356 return (~sum & 0xffff);
357 }
Cache object: def86a89762d298cf50b459ef63d5540
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