1 /* SPDX-License-Identifier: BSD-2-Clause */
2 /*
3 * Socket Address handling for dhcpcd
4 * Copyright (c) 2015-2021 Roy Marples <roy@marples.name>
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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/socket.h>
30 #include <sys/types.h>
31
32 #include <arpa/inet.h>
33 #ifdef AF_LINK
34 #include <net/if_dl.h>
35 #elif defined(AF_PACKET)
36 #include <linux/if_packet.h>
37 #endif
38
39 #include <assert.h>
40 #include <errno.h>
41 #include <stdbool.h>
42 #include <stddef.h>
43 #include <stdio.h>
44 #include <stdint.h>
45 #include <string.h>
46
47 #include "config.h"
48 #include "common.h"
49 #include "sa.h"
50
51 #ifndef NDEBUG
52 static bool sa_inprefix;
53 #endif
54
55 socklen_t
sa_addroffset(const struct sockaddr * sa)56 sa_addroffset(const struct sockaddr *sa)
57 {
58
59 assert(sa != NULL);
60 switch(sa->sa_family) {
61 #ifdef INET
62 case AF_INET:
63 return offsetof(struct sockaddr_in, sin_addr) +
64 offsetof(struct in_addr, s_addr);
65 #endif /* INET */
66 #ifdef INET6
67 case AF_INET6:
68 return offsetof(struct sockaddr_in6, sin6_addr) +
69 offsetof(struct in6_addr, s6_addr);
70 #endif /* INET6 */
71 default:
72 errno = EAFNOSUPPORT;
73 return 0;
74 }
75 }
76
77 socklen_t
sa_addrlen(const struct sockaddr * sa)78 sa_addrlen(const struct sockaddr *sa)
79 {
80 #define membersize(type, member) sizeof(((type *)0)->member)
81 assert(sa != NULL);
82 switch(sa->sa_family) {
83 #ifdef INET
84 case AF_INET:
85 return membersize(struct in_addr, s_addr);
86 #endif /* INET */
87 #ifdef INET6
88 case AF_INET6:
89 return membersize(struct in6_addr, s6_addr);
90 #endif /* INET6 */
91 default:
92 errno = EAFNOSUPPORT;
93 return 0;
94 }
95 }
96
97 #ifndef HAVE_SA_LEN
98 socklen_t
sa_len(const struct sockaddr * sa)99 sa_len(const struct sockaddr *sa)
100 {
101
102 switch (sa->sa_family) {
103 #ifdef AF_LINK
104 case AF_LINK:
105 return sizeof(struct sockaddr_dl);
106 #endif
107 #ifdef AF_PACKET
108 case AF_PACKET:
109 return sizeof(struct sockaddr_ll);
110 #endif
111 case AF_INET:
112 return sizeof(struct sockaddr_in);
113 case AF_INET6:
114 return sizeof(struct sockaddr_in6);
115 default:
116 return sizeof(struct sockaddr);
117 }
118 }
119 #endif
120
121 bool
sa_is_unspecified(const struct sockaddr * sa)122 sa_is_unspecified(const struct sockaddr *sa)
123 {
124
125 assert(sa != NULL);
126 switch(sa->sa_family) {
127 case AF_UNSPEC:
128 return true;
129 #ifdef INET
130 case AF_INET:
131 return satocsin(sa)->sin_addr.s_addr == INADDR_ANY;
132 #endif /* INET */
133 #ifdef INET6
134 case AF_INET6:
135 return IN6_IS_ADDR_UNSPECIFIED(&satocsin6(sa)->sin6_addr);
136 #endif /* INET6 */
137 default:
138 errno = EAFNOSUPPORT;
139 return false;
140 }
141 }
142
143 #ifdef INET6
144 #ifndef IN6MASK128
145 #define IN6MASK128 {{{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, \
146 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }}}
147 #endif
148 static const struct in6_addr in6allones = IN6MASK128;
149 #endif
150
151 bool
sa_is_allones(const struct sockaddr * sa)152 sa_is_allones(const struct sockaddr *sa)
153 {
154
155 assert(sa != NULL);
156 switch(sa->sa_family) {
157 case AF_UNSPEC:
158 return false;
159 #ifdef INET
160 case AF_INET:
161 {
162 const struct sockaddr_in *sin;
163
164 sin = satocsin(sa);
165 return sin->sin_addr.s_addr == INADDR_BROADCAST;
166 }
167 #endif /* INET */
168 #ifdef INET6
169 case AF_INET6:
170 {
171 const struct sockaddr_in6 *sin6;
172
173 sin6 = satocsin6(sa);
174 return IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr, &in6allones);
175 }
176 #endif /* INET6 */
177 default:
178 errno = EAFNOSUPPORT;
179 return false;
180 }
181 }
182
183 bool
sa_is_loopback(const struct sockaddr * sa)184 sa_is_loopback(const struct sockaddr *sa)
185 {
186
187 assert(sa != NULL);
188 switch(sa->sa_family) {
189 case AF_UNSPEC:
190 return false;
191 #ifdef INET
192 case AF_INET:
193 {
194 const struct sockaddr_in *sin;
195
196 sin = satocsin(sa);
197 return sin->sin_addr.s_addr == htonl(INADDR_LOOPBACK);
198 }
199 #endif /* INET */
200 #ifdef INET6
201 case AF_INET6:
202 {
203 const struct sockaddr_in6 *sin6;
204
205 sin6 = satocsin6(sa);
206 return IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr);
207 }
208 #endif /* INET6 */
209 default:
210 errno = EAFNOSUPPORT;
211 return false;
212 }
213 }
214
215 int
sa_toprefix(const struct sockaddr * sa)216 sa_toprefix(const struct sockaddr *sa)
217 {
218 int prefix;
219
220 assert(sa != NULL);
221 switch(sa->sa_family) {
222 #ifdef INET
223 case AF_INET:
224 {
225 const struct sockaddr_in *sin;
226 uint32_t mask;
227
228 sin = satocsin(sa);
229 if (sin->sin_addr.s_addr == INADDR_ANY) {
230 prefix = 0;
231 break;
232 }
233 mask = ntohl(sin->sin_addr.s_addr);
234 prefix = 33 - ffs((int)mask); /* 33 - (1 .. 32) -> 32 .. 1 */
235 if (prefix < 32) { /* more than 1 bit in mask */
236 /* check for non-contig netmask */
237 if ((mask^(((1U << prefix)-1) << (32 - prefix))) != 0) {
238 errno = EINVAL;
239 return -1; /* noncontig, no pfxlen */
240 }
241 }
242 break;
243 }
244 #endif
245 #ifdef INET6
246 case AF_INET6:
247 {
248 const struct sockaddr_in6 *sin6;
249 int x, y;
250 const uint8_t *lim, *p;
251
252 sin6 = satocsin6(sa);
253 p = (const uint8_t *)sin6->sin6_addr.s6_addr;
254 lim = p + sizeof(sin6->sin6_addr.s6_addr);
255 for (x = 0; p < lim; x++, p++) {
256 if (*p != 0xff)
257 break;
258 }
259 y = 0;
260 if (p < lim) {
261 for (y = 0; y < NBBY; y++) {
262 if ((*p & (0x80 >> y)) == 0)
263 break;
264 }
265 }
266
267 /*
268 * when the limit pointer is given, do a stricter check on the
269 * remaining bits.
270 */
271 if (p < lim) {
272 if (y != 0 && (*p & (0x00ff >> y)) != 0)
273 return 0;
274 for (p = p + 1; p < lim; p++)
275 if (*p != 0)
276 return 0;
277 }
278
279 prefix = x * NBBY + y;
280 break;
281 }
282 #endif
283 default:
284 errno = EAFNOSUPPORT;
285 return -1;
286 }
287
288 #ifndef NDEBUG
289 /* Ensure the calculation is correct */
290 if (!sa_inprefix) {
291 union sa_ss ss = { .sa = { .sa_family = sa->sa_family } };
292
293 sa_inprefix = true;
294 sa_fromprefix(&ss.sa, prefix);
295 assert(sa_cmp(sa, &ss.sa) == 0);
296 sa_inprefix = false;
297 }
298 #endif
299
300 return prefix;
301 }
302
303 int
sa_fromprefix(struct sockaddr * sa,int prefix)304 sa_fromprefix(struct sockaddr *sa, int prefix)
305 {
306 uint8_t *ap;
307 int max_prefix, bytes, bits, i;
308
309 switch (sa->sa_family) {
310 #ifdef INET
311 case AF_INET:
312 max_prefix = 32;
313 #ifdef HAVE_SA_LEN
314 sa->sa_len = sizeof(struct sockaddr_in);
315 #endif
316 break;
317 #endif
318 #ifdef INET6
319 case AF_INET6:
320 max_prefix = 128;
321 #ifdef HAVE_SA_LEN
322 sa->sa_len = sizeof(struct sockaddr_in6);
323 #endif
324 break;
325 #endif
326 default:
327 errno = EAFNOSUPPORT;
328 return -1;
329 }
330
331 bytes = prefix / NBBY;
332 bits = prefix % NBBY;
333
334 ap = (uint8_t *)sa + sa_addroffset(sa);
335 for (i = 0; i < bytes; i++)
336 *ap++ = 0xff;
337 if (bits) {
338 uint8_t a;
339
340 a = 0xff;
341 a = (uint8_t)(a << (8 - bits));
342 *ap++ = a;
343 }
344 bytes = (max_prefix - prefix) / NBBY;
345 for (i = 0; i < bytes; i++)
346 *ap++ = 0x00;
347
348 #ifndef NDEBUG
349 /* Ensure the calculation is correct */
350 if (!sa_inprefix) {
351 sa_inprefix = true;
352 assert(sa_toprefix(sa) == prefix);
353 sa_inprefix = false;
354 }
355 #endif
356 return 0;
357 }
358
359 /* inet_ntop, but for sockaddr. */
360 const char *
sa_addrtop(const struct sockaddr * sa,char * buf,socklen_t len)361 sa_addrtop(const struct sockaddr *sa, char *buf, socklen_t len)
362 {
363 const void *addr;
364
365 assert(buf != NULL);
366 assert(len > 0);
367
368 if (sa->sa_family == 0) {
369 *buf = '\0';
370 return NULL;
371 }
372
373 #ifdef AF_LINK
374 #ifndef CLLADDR
375 #define CLLADDR(sdl) (const void *)((sdl)->sdl_data + (sdl)->sdl_nlen)
376 #endif
377 if (sa->sa_family == AF_LINK) {
378 const struct sockaddr_dl *sdl;
379
380 sdl = (const void *)sa;
381 if (sdl->sdl_alen == 0) {
382 if (snprintf(buf, len, "link#%d", sdl->sdl_index) == -1)
383 return NULL;
384 return buf;
385 }
386 return hwaddr_ntoa(CLLADDR(sdl), sdl->sdl_alen, buf, len);
387 }
388 #elif defined(AF_PACKET)
389 if (sa->sa_family == AF_PACKET) {
390 const struct sockaddr_ll *sll;
391
392 sll = (const void *)sa;
393 return hwaddr_ntoa(sll->sll_addr, sll->sll_halen, buf, len);
394 }
395 #endif
396 addr = (const char *)sa + sa_addroffset(sa);
397 return inet_ntop(sa->sa_family, addr, buf, len);
398 }
399
400 int
sa_cmp(const struct sockaddr * sa1,const struct sockaddr * sa2)401 sa_cmp(const struct sockaddr *sa1, const struct sockaddr *sa2)
402 {
403 socklen_t offset, len;
404
405 assert(sa1 != NULL);
406 assert(sa2 != NULL);
407
408 /* Treat AF_UNSPEC as the unspecified address. */
409 if ((sa1->sa_family == AF_UNSPEC || sa2->sa_family == AF_UNSPEC) &&
410 sa_is_unspecified(sa1) && sa_is_unspecified(sa2))
411 return 0;
412
413 if (sa1->sa_family != sa2->sa_family)
414 return sa1->sa_family - sa2->sa_family;
415
416 #ifdef HAVE_SA_LEN
417 len = MIN(sa1->sa_len, sa2->sa_len);
418 #endif
419
420 switch (sa1->sa_family) {
421 #ifdef INET
422 case AF_INET:
423 offset = offsetof(struct sockaddr_in, sin_addr);
424 #ifdef HAVE_SA_LEN
425 len -= offset;
426 len = MIN(len, sizeof(struct in_addr));
427 #else
428 len = sizeof(struct in_addr);
429 #endif
430 break;
431 #endif
432 #ifdef INET6
433 case AF_INET6:
434 offset = offsetof(struct sockaddr_in6, sin6_addr);
435 #ifdef HAVE_SA_LEN
436 len -= offset;
437 len = MIN(len, sizeof(struct in6_addr));
438 #else
439 len = sizeof(struct in6_addr);
440 #endif
441 break;
442 #endif
443 default:
444 offset = 0;
445 #ifndef HAVE_SA_LEN
446 len = sizeof(struct sockaddr);
447 #endif
448 break;
449 }
450
451 return memcmp((const char *)sa1 + offset,
452 (const char *)sa2 + offset,
453 len);
454 }
455
456 #ifdef INET
457 void
sa_in_init(struct sockaddr * sa,const struct in_addr * addr)458 sa_in_init(struct sockaddr *sa, const struct in_addr *addr)
459 {
460 struct sockaddr_in *sin;
461
462 assert(sa != NULL);
463 assert(addr != NULL);
464 sin = satosin(sa);
465 sin->sin_family = AF_INET;
466 #ifdef HAVE_SA_LEN
467 sin->sin_len = sizeof(*sin);
468 #endif
469 sin->sin_addr.s_addr = addr->s_addr;
470 }
471 #endif
472
473 #ifdef INET6
474 void
sa_in6_init(struct sockaddr * sa,const struct in6_addr * addr)475 sa_in6_init(struct sockaddr *sa, const struct in6_addr *addr)
476 {
477 struct sockaddr_in6 *sin6;
478
479 assert(sa != NULL);
480 assert(addr != NULL);
481 sin6 = satosin6(sa);
482 sin6->sin6_family = AF_INET6;
483 #ifdef HAVE_SA_LEN
484 sin6->sin6_len = sizeof(*sin6);
485 #endif
486 memcpy(&sin6->sin6_addr.s6_addr, &addr->s6_addr,
487 sizeof(sin6->sin6_addr.s6_addr));
488 }
489 #endif
490