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: src/sys/netinet6/in6_cksum.c,v 1.17 2007/12/10 16:03:37 obrien Exp $");
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]; ADDCARRY(sum);}
82
83 /*
84 * m MUST contain a continuous IP6 header.
85 * off is an offset where TCP/UDP/ICMP6 header starts.
86 * len is a total length of a transport segment.
87 * (e.g. TCP header + TCP payload)
88 */
89 int
90 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
91 {
92 u_int16_t *w;
93 int sum = 0;
94 int mlen = 0;
95 int byte_swapped = 0;
96 struct ip6_hdr *ip6;
97 struct in6_addr in6;
98 union {
99 u_int16_t phs[4];
100 struct {
101 u_int32_t ph_len;
102 u_int8_t ph_zero[3];
103 u_int8_t ph_nxt;
104 } __packed ph;
105 } uph;
106 union {
107 u_int8_t c[2];
108 u_int16_t s;
109 } s_util;
110 union {
111 u_int16_t s[2];
112 u_int32_t l;
113 } l_util;
114
115 /* sanity check */
116 if (m->m_pkthdr.len < off + len) {
117 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)",
118 m->m_pkthdr.len, off, len);
119 }
120
121 bzero(&uph, sizeof(uph));
122
123 /*
124 * First create IP6 pseudo header and calculate a summary.
125 */
126 ip6 = mtod(m, struct ip6_hdr *);
127 uph.ph.ph_len = htonl(len);
128 uph.ph.ph_nxt = nxt;
129
130 /*
131 * IPv6 source address.
132 * XXX: we'd like to avoid copying the address, but we can't due to
133 * the possibly embedded scope zone ID.
134 */
135 in6 = ip6->ip6_src;
136 in6_clearscope(&in6);
137 w = (u_int16_t *)&in6;
138 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
139 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
140
141 /* IPv6 destination address */
142 in6 = ip6->ip6_dst;
143 in6_clearscope(&in6);
144 w = (u_int16_t *)&in6;
145 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
146 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
147
148 /* Payload length and upper layer identifier */
149 sum += uph.phs[0]; sum += uph.phs[1];
150 sum += uph.phs[2]; sum += uph.phs[3];
151
152 /*
153 * Secondly calculate a summary of the first mbuf excluding offset.
154 */
155 while (off > 0) {
156 if (m->m_len <= off)
157 off -= m->m_len;
158 else
159 break;
160 m = m->m_next;
161 }
162 w = (u_int16_t *)(mtod(m, u_char *) + off);
163 mlen = m->m_len - off;
164 if (len < mlen)
165 mlen = len;
166 len -= mlen;
167 /*
168 * Force to even boundary.
169 */
170 if ((1 & (long) w) && (mlen > 0)) {
171 REDUCE;
172 sum <<= 8;
173 s_util.c[0] = *(u_char *)w;
174 w = (u_int16_t *)((char *)w + 1);
175 mlen--;
176 byte_swapped = 1;
177 }
178 /*
179 * Unroll the loop to make overhead from
180 * branches &c small.
181 */
182 while ((mlen -= 32) >= 0) {
183 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
184 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
185 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
186 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
187 w += 16;
188 }
189 mlen += 32;
190 while ((mlen -= 8) >= 0) {
191 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
192 w += 4;
193 }
194 mlen += 8;
195 if (mlen == 0 && byte_swapped == 0)
196 goto next;
197 REDUCE;
198 while ((mlen -= 2) >= 0) {
199 sum += *w++;
200 }
201 if (byte_swapped) {
202 REDUCE;
203 sum <<= 8;
204 byte_swapped = 0;
205 if (mlen == -1) {
206 s_util.c[1] = *(char *)w;
207 sum += s_util.s;
208 mlen = 0;
209 } else
210 mlen = -1;
211 } else if (mlen == -1)
212 s_util.c[0] = *(char *)w;
213 next:
214 m = m->m_next;
215
216 /*
217 * Lastly calculate a summary of the rest of mbufs.
218 */
219
220 for (;m && len; m = m->m_next) {
221 if (m->m_len == 0)
222 continue;
223 w = mtod(m, u_int16_t *);
224 if (mlen == -1) {
225 /*
226 * The first byte of this mbuf is the continuation
227 * of a word spanning between this mbuf and the
228 * last mbuf.
229 *
230 * s_util.c[0] is already saved when scanning previous
231 * mbuf.
232 */
233 s_util.c[1] = *(char *)w;
234 sum += s_util.s;
235 w = (u_int16_t *)((char *)w + 1);
236 mlen = m->m_len - 1;
237 len--;
238 } else
239 mlen = m->m_len;
240 if (len < mlen)
241 mlen = len;
242 len -= mlen;
243 /*
244 * Force to even boundary.
245 */
246 if ((1 & (long) w) && (mlen > 0)) {
247 REDUCE;
248 sum <<= 8;
249 s_util.c[0] = *(u_char *)w;
250 w = (u_int16_t *)((char *)w + 1);
251 mlen--;
252 byte_swapped = 1;
253 }
254 /*
255 * Unroll the loop to make overhead from
256 * branches &c small.
257 */
258 while ((mlen -= 32) >= 0) {
259 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
260 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
261 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
262 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
263 w += 16;
264 }
265 mlen += 32;
266 while ((mlen -= 8) >= 0) {
267 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
268 w += 4;
269 }
270 mlen += 8;
271 if (mlen == 0 && byte_swapped == 0)
272 continue;
273 REDUCE;
274 while ((mlen -= 2) >= 0) {
275 sum += *w++;
276 }
277 if (byte_swapped) {
278 REDUCE;
279 sum <<= 8;
280 byte_swapped = 0;
281 if (mlen == -1) {
282 s_util.c[1] = *(char *)w;
283 sum += s_util.s;
284 mlen = 0;
285 } else
286 mlen = -1;
287 } else if (mlen == -1)
288 s_util.c[0] = *(char *)w;
289 }
290 if (len)
291 panic("in6_cksum: out of data");
292 if (mlen == -1) {
293 /* The last mbuf has odd # of bytes. Follow the
294 standard (the odd byte may be shifted left by 8 bits
295 or not as determined by endian-ness of the machine) */
296 s_util.c[1] = 0;
297 sum += s_util.s;
298 }
299 REDUCE;
300 return (~sum & 0xffff);
301 }
302
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