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
63 #include <sys/param.h>
64 #include <sys/mbuf.h>
65 #include <sys/systm.h>
66 #include <netinet/in.h>
67 #include <netinet/ip6.h>
68 #include <netinet6/scope6_var.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]; (void)ADDCARRY(sum);}
79
80 union l_util {
81 uint16_t s[2];
82 uint32_t l;
83 };
84
85 union s_util {
86 uint8_t c[2];
87 uint16_t s;
88 };
89
90 static int
_in6_cksum_pseudo(struct ip6_hdr * ip6,uint32_t len,uint8_t nxt,uint16_t csum)91 _in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
92 {
93 int sum;
94 uint16_t scope, *w;
95 union {
96 u_int16_t phs[4];
97 struct {
98 u_int32_t ph_len;
99 u_int8_t ph_zero[3];
100 u_int8_t ph_nxt;
101 } __packed ph;
102 } uph;
103
104 sum = csum;
105
106 /*
107 * First create IP6 pseudo header and calculate a summary.
108 */
109 uph.ph.ph_len = htonl(len);
110 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
111 uph.ph.ph_nxt = nxt;
112
113 /* Payload length and upper layer identifier. */
114 sum += uph.phs[0]; sum += uph.phs[1];
115 sum += uph.phs[2]; sum += uph.phs[3];
116
117 /* IPv6 source address. */
118 scope = in6_getscope(&ip6->ip6_src);
119 w = (u_int16_t *)&ip6->ip6_src;
120 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
121 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
122 if (scope != 0)
123 sum -= scope;
124
125 /* IPv6 destination address. */
126 scope = in6_getscope(&ip6->ip6_dst);
127 w = (u_int16_t *)&ip6->ip6_dst;
128 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
129 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
130 if (scope != 0)
131 sum -= scope;
132
133 return (sum);
134 }
135
136 int
in6_cksum_pseudo(struct ip6_hdr * ip6,uint32_t len,uint8_t nxt,uint16_t csum)137 in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
138 {
139 union l_util l_util;
140 int sum;
141
142 sum = _in6_cksum_pseudo(ip6, len, nxt, csum);
143 REDUCE;
144 return (sum);
145 }
146
147 static int
in6_cksumdata(void * data,int * lenp,uint8_t * residp,int rlen)148 in6_cksumdata(void *data, int *lenp, uint8_t *residp, int rlen)
149 {
150 union l_util l_util;
151 union s_util s_util;
152 uint16_t *w;
153 int len, sum;
154 bool byte_swapped;
155
156 KASSERT(*lenp >= 0, ("%s: negative len %d", __func__, *lenp));
157 KASSERT(rlen == 0 || rlen == 1, ("%s: rlen %d", __func__, rlen));
158
159 len = *lenp;
160 sum = 0;
161
162 if (len == 0) {
163 len = rlen;
164 goto out;
165 }
166
167 byte_swapped = false;
168 w = data;
169
170 /*
171 * Do we have a residual byte left over from the previous buffer?
172 */
173 if (rlen == 1) {
174 s_util.c[0] = *residp;
175 s_util.c[1] = *(uint8_t *)w;
176 sum += s_util.s;
177 w = (uint16_t *)((uint8_t *)w + 1);
178 len--;
179 rlen = 0;
180 }
181
182 /*
183 * Force to even boundary.
184 */
185 if ((1 & (uintptr_t)w) && len > 0) {
186 REDUCE;
187 sum <<= 8;
188 s_util.c[0] = *(uint8_t *)w;
189 w = (uint16_t *)((uint8_t *)w + 1);
190 len--;
191 byte_swapped = true;
192 }
193
194 /*
195 * Unroll the loop to make overhead from branches &c small.
196 */
197 while ((len -= 32) >= 0) {
198 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
199 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
200 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
201 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
202 w += 16;
203 }
204 len += 32;
205 while ((len -= 8) >= 0) {
206 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
207 w += 4;
208 }
209 len += 8;
210 if (len == 0 && !byte_swapped)
211 goto out;
212 REDUCE;
213 while ((len -= 2) >= 0) {
214 sum += *w++;
215 }
216 if (byte_swapped) {
217 REDUCE;
218 sum <<= 8;
219 if (len == -1) {
220 s_util.c[1] = *(uint8_t *)w;
221 sum += s_util.s;
222 } else /* len == -2 */
223 *residp = s_util.c[0];
224 len++;
225 } else if (len == -1)
226 *residp = *(uint8_t *)w;
227 out:
228 *lenp = len & 1;
229 return (sum);
230 }
231
232 struct in6_cksum_partial_arg {
233 int sum;
234 int rlen;
235 uint8_t resid;
236 };
237
238 static int
in6_cksum_partial_one(void * _arg,void * data,u_int len)239 in6_cksum_partial_one(void *_arg, void *data, u_int len)
240 {
241 struct in6_cksum_partial_arg *arg = _arg;
242
243 arg->sum += in6_cksumdata(data, &len, &arg->resid, arg->rlen);
244 arg->rlen = len;
245 return (0);
246 }
247
248 /*
249 * m MUST contain a contiguous IP6 header.
250 * off is an offset where TCP/UDP/ICMP6 header starts.
251 * len is a total length of a transport segment.
252 * (e.g. TCP header + TCP payload)
253 * cov is the number of bytes to be taken into account for the checksum
254 */
255 int
in6_cksum_partial(struct mbuf * m,uint8_t nxt,uint32_t off,uint32_t len,uint32_t cov)256 in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len,
257 uint32_t cov)
258 {
259 struct in6_cksum_partial_arg arg;
260 union l_util l_util;
261 union s_util s_util;
262 struct ip6_hdr *ip6;
263 uint16_t *w, scope;
264 int sum;
265 union {
266 uint16_t phs[4];
267 struct {
268 uint32_t ph_len;
269 uint8_t ph_zero[3];
270 uint8_t ph_nxt;
271 } __packed ph;
272 } uph;
273
274 /* Sanity check. */
275 KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+"
276 "len(%d)", __func__, m->m_pkthdr.len, off, len));
277 KASSERT(m->m_len >= sizeof(*ip6),
278 ("%s: mbuf len %d < sizeof(ip6)", __func__, m->m_len));
279
280 /*
281 * First create IP6 pseudo header and calculate a summary.
282 */
283 uph.ph.ph_len = htonl(len);
284 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
285 uph.ph.ph_nxt = nxt;
286
287 /* Payload length and upper layer identifier. */
288 sum = uph.phs[0]; sum += uph.phs[1];
289 sum += uph.phs[2]; sum += uph.phs[3];
290
291 ip6 = mtod(m, struct ip6_hdr *);
292
293 /* IPv6 source address. */
294 scope = in6_getscope(&ip6->ip6_src);
295 w = (uint16_t *)&ip6->ip6_src;
296 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
297 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
298 if (scope != 0)
299 sum -= scope;
300
301 /* IPv6 destination address. */
302 scope = in6_getscope(&ip6->ip6_dst);
303 w = (uint16_t *)&ip6->ip6_dst;
304 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
305 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
306 if (scope != 0)
307 sum -= scope;
308
309 /*
310 * Loop over the rest of the mbuf chain and compute the rest of the
311 * checksum. m_apply() handles unmapped mbufs.
312 */
313 arg.sum = sum;
314 arg.rlen = 0;
315 (void)m_apply(m, off, cov, in6_cksum_partial_one, &arg);
316 sum = arg.sum;
317
318 /*
319 * Handle a residual byte.
320 */
321 if (arg.rlen == 1) {
322 s_util.c[0] = arg.resid;
323 s_util.c[1] = 0;
324 sum += s_util.s;
325 }
326 REDUCE;
327 return (~sum & 0xffff);
328 }
329
330 int
in6_cksum(struct mbuf * m,uint8_t nxt,uint32_t off,uint32_t len)331 in6_cksum(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len)
332 {
333 return (in6_cksum_partial(m, nxt, off, len, len));
334 }
335