1 /* $OpenBSD: in6_cksum.c,v 1.18 2019/04/22 22:47:49 bluhm Exp $ */
2 /* $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 itojun Exp $ */
3
4 /*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /*
34 * Copyright (c) 1988, 1992, 1993
35 * The Regents of the University of California. All rights reserved.
36 *
37 * Redistribution and use in source and binary forms, with or without
38 * modification, are permitted provided that the following conditions
39 * are met:
40 * 1. Redistributions of source code must retain the above copyright
41 * notice, this list of conditions and the following disclaimer.
42 * 2. Redistributions in binary form must reproduce the above copyright
43 * notice, this list of conditions and the following disclaimer in the
44 * documentation and/or other materials provided with the distribution.
45 * 3. Neither the name of the University nor the names of its contributors
46 * may be used to endorse or promote products derived from this software
47 * without specific prior written permission.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59 * SUCH DAMAGE.
60 *
61 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
62 */
63
64 #include <sys/param.h>
65 #include <sys/mbuf.h>
66 #include <sys/systm.h>
67 #include <netinet/in.h>
68 #include <netinet/ip6.h>
69
70 /*
71 * Checksum routine for Internet Protocol family headers (Portable Version).
72 *
73 * This routine is very heavily used in the network
74 * code and should be modified for each CPU to be as fast as possible.
75 */
76
77 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
78 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
79
80 /*
81 * m MUST contain a continuous IP6 header.
82 * off is a offset where TCP/UDP/ICMP6 header starts.
83 * len is a total length of a transport segment.
84 * (e.g. TCP header + TCP payload)
85 */
86
87 int
88 in6_cksum(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len)
89 {
90 uint16_t *w;
91 int sum = 0;
92 int mlen = 0;
93 int byte_swapped = 0;
94 struct ip6_hdr *ip6;
95 union {
96 uint16_t phs[4];
97 struct {
98 uint32_t ph_len;
99 uint8_t ph_zero[3];
100 uint8_t ph_nxt;
101 } ph __packed;
102 } uph;
103 union {
104 uint8_t c[2];
105 uint16_t s;
106 } s_util;
107 union {
108 uint16_t s[2];
109 uint32_t l;
110 } l_util;
111
112 /* sanity check */
113 if (m->m_pkthdr.len < off + len) {
114 panic("%s: mbuf len (%d) < off+len (%d+%d)",
115 __func__, m->m_pkthdr.len, off, len);
116 }
117
118 /* Skip pseudo-header if nxt == 0. */
119 if (nxt == 0)
120 goto skip_phdr;
121
122 bzero(&uph, sizeof(uph));
123
124 /*
125 * First create IP6 pseudo header and calculate a summary.
126 */
127 ip6 = mtod(m, struct ip6_hdr *);
128 w = (uint16_t *)&ip6->ip6_src;
129 uph.ph.ph_len = htonl(len);
130 uph.ph.ph_nxt = nxt;
131
132 /* IPv6 source address */
133 sum += w[0];
134 if (!IN6_IS_SCOPE_EMBED(&ip6->ip6_src))
135 sum += w[1];
136 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5];
137 sum += w[6]; sum += w[7];
138 /* IPv6 destination address */
139 sum += w[8];
140 if (!IN6_IS_SCOPE_EMBED(&ip6->ip6_dst))
141 sum += w[9];
142 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13];
143 sum += w[14]; sum += w[15];
144 /* Payload length and upper layer identifier */
145 sum += uph.phs[0]; sum += uph.phs[1];
146 sum += uph.phs[2]; sum += uph.phs[3];
147
148 skip_phdr:
149 /*
150 * Secondly calculate a summary of the first mbuf excluding offset.
151 */
152 while (m != NULL && off > 0) {
153 if (m->m_len <= off)
154 off -= m->m_len;
155 else
156 break;
157 m = m->m_next;
158 }
159 if (m == NULL) {
160 if (off)
161 panic("%s: out of header, off %u", __func__, off);
162 goto end;
163 }
164 w = (uint16_t *)(mtod(m, uint8_t *) + off);
165 mlen = m->m_len - off;
166 if (len < mlen)
167 mlen = len;
168 len -= mlen;
169 /*
170 * Force to even boundary.
171 */
172 if ((1 & (long) w) && (mlen > 0)) {
173 REDUCE;
174 sum <<= 8;
175 s_util.c[0] = *(uint8_t *)w;
176 w = (uint16_t *)((uint8_t *)w + 1);
177 mlen--;
178 byte_swapped = 1;
179 }
180 /*
181 * Unroll the loop to make overhead from
182 * branches &c small.
183 */
184 while ((mlen -= 32) >= 0) {
185 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
186 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
187 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
188 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
189 w += 16;
190 }
191 mlen += 32;
192 while ((mlen -= 8) >= 0) {
193 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
194 w += 4;
195 }
196 mlen += 8;
197 if (mlen == 0 && byte_swapped == 0)
198 goto next;
199 REDUCE;
200 while ((mlen -= 2) >= 0) {
201 sum += *w++;
202 }
203 if (byte_swapped) {
204 REDUCE;
205 sum <<= 8;
206 byte_swapped = 0;
207 if (mlen == -1) {
208 s_util.c[1] = *(uint8_t *)w;
209 sum += s_util.s;
210 mlen = 0;
211 } else
212 mlen = -1;
213 } else if (mlen == -1)
214 s_util.c[0] = *(uint8_t *)w;
215 next:
216 m = m->m_next;
217
218 /*
219 * Lastly calculate a summary of the rest of mbufs.
220 */
221
222 for (;m && len; m = m->m_next) {
223 if (m->m_len == 0)
224 continue;
225 w = mtod(m, uint16_t *);
226 if (mlen == -1) {
227 /*
228 * The first byte of this mbuf is the continuation
229 * of a word spanning between this mbuf and the
230 * last mbuf.
231 *
232 * s_util.c[0] is already saved when scanning previous
233 * mbuf.
234 */
235 s_util.c[1] = *(uint8_t *)w;
236 sum += s_util.s;
237 w = (uint16_t *)((uint8_t *)w + 1);
238 mlen = m->m_len - 1;
239 len--;
240 } else
241 mlen = m->m_len;
242 if (len < mlen)
243 mlen = len;
244 len -= mlen;
245 /*
246 * Force to even boundary.
247 */
248 if ((1 & (long) w) && (mlen > 0)) {
249 REDUCE;
250 sum <<= 8;
251 s_util.c[0] = *(uint8_t *)w;
252 w = (uint16_t *)((uint8_t *)w + 1);
253 mlen--;
254 byte_swapped = 1;
255 }
256 /*
257 * Unroll the loop to make overhead from
258 * branches &c small.
259 */
260 while ((mlen -= 32) >= 0) {
261 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
262 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
263 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
264 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
265 w += 16;
266 }
267 mlen += 32;
268 while ((mlen -= 8) >= 0) {
269 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
270 w += 4;
271 }
272 mlen += 8;
273 if (mlen == 0 && byte_swapped == 0)
274 continue;
275 REDUCE;
276 while ((mlen -= 2) >= 0) {
277 sum += *w++;
278 }
279 if (byte_swapped) {
280 REDUCE;
281 sum <<= 8;
282 byte_swapped = 0;
283 if (mlen == -1) {
284 s_util.c[1] = *(uint8_t *)w;
285 sum += s_util.s;
286 mlen = 0;
287 } else
288 mlen = -1;
289 } else if (mlen == -1)
290 s_util.c[0] = *(uint8_t *)w;
291 }
292 end:
293 if (len)
294 panic("%s: out of data, len %u", __func__, len);
295 if (mlen == -1) {
296 /* The last mbuf has odd # of bytes. Follow the
297 standard (the odd byte may be shifted left by 8 bits
298 or not as determined by endian-ness of the machine) */
299 s_util.c[1] = 0;
300 sum += s_util.s;
301 }
302 REDUCE;
303 return (~sum & 0xffff);
304 }
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