contrib/dhcpcd/src/sa.c

   1 /* SPDX-License-Identifier: BSD-2-Clause */
   2 /*
   3  * Socket Address handling for dhcpcd
   4  * Copyright (c) 2015-2023 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
  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
  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
  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
 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
 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
 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
 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 static void
 304 ipbytes_fromprefix(uint8_t *ap, int prefix, int max_prefix)
 305 {
 306         int bytes, bits, i;
 307
 308         bytes = prefix / NBBY;
 309         bits = prefix % NBBY;
 310
 311         for (i = 0; i < bytes; i++)
 312                 *ap++ = 0xff;
 313         if (bits) {
 314                 uint8_t a;
 315
 316                 a = 0xff;
 317                 a  = (uint8_t)(a << (8 - bits));
 318                 *ap++ = a;
 319         }
 320         bytes = (max_prefix - prefix) / NBBY;
 321         for (i = 0; i < bytes; i++)
 322                 *ap++ = 0x00;
 323 }
 324
 325 void
 326 in6_addr_fromprefix(struct in6_addr *addr, int prefix)
 327 {
 328         ipbytes_fromprefix((uint8_t *)addr, prefix, 128);
 329 }
 330
 331 int
 332 sa_fromprefix(struct sockaddr *sa, int prefix)
 333 {
 334         uint8_t *ap;
 335         int max_prefix;
 336
 337         switch (sa->sa_family) {
 338 #ifdef INET
 339         case AF_INET:
 340                 max_prefix = 32;
 341 #ifdef HAVE_SA_LEN
 342                 sa->sa_len = sizeof(struct sockaddr_in);
 343 #endif
 344                 break;
 345 #endif
 346 #ifdef INET6
 347         case AF_INET6:
 348                 max_prefix = 128;
 349 #ifdef HAVE_SA_LEN
 350                 sa->sa_len = sizeof(struct sockaddr_in6);
 351 #endif
 352                 break;
 353 #endif
 354         default:
 355                 errno = EAFNOSUPPORT;
 356                 return -1;
 357         }
 358
 359         ap = (uint8_t *)sa + sa_addroffset(sa);
 360         ipbytes_fromprefix(ap, prefix, max_prefix);
 361
 362 #ifndef NDEBUG
 363         /* Ensure the calculation is correct */
 364         if (!sa_inprefix) {
 365                 sa_inprefix = true;
 366                 assert(sa_toprefix(sa) == prefix);
 367                 sa_inprefix = false;
 368         }
 369 #endif
 370         return 0;
 371 }
 372
 373 /* inet_ntop, but for sockaddr. */
 374 const char *
 375 sa_addrtop(const struct sockaddr *sa, char *buf, socklen_t len)
 376 {
 377         const void *addr;
 378
 379         assert(buf != NULL);
 380         assert(len > 0);
 381
 382         if (sa->sa_family == 0) {
 383                 *buf = '\0';
 384                 return NULL;
 385         }
 386
 387 #ifdef AF_LINK
 388 #ifndef CLLADDR
 389 #define CLLADDR(sdl) (const void *)((sdl)->sdl_data + (sdl)->sdl_nlen)
 390 #endif
 391         if (sa->sa_family == AF_LINK) {
 392                 const struct sockaddr_dl *sdl;
 393
 394                 sdl = (const void *)sa;
 395                 if (sdl->sdl_alen == 0) {
 396                         if (snprintf(buf, len, "link#%d", sdl->sdl_index) == -1)
 397                                 return NULL;
 398                         return buf;
 399                 }
 400                 return hwaddr_ntoa(CLLADDR(sdl), sdl->sdl_alen, buf, len);
 401         }
 402 #elif defined(AF_PACKET)
 403         if (sa->sa_family == AF_PACKET) {
 404                 const struct sockaddr_ll *sll;
 405
 406                 sll = (const void *)sa;
 407                 return hwaddr_ntoa(sll->sll_addr, sll->sll_halen, buf, len);
 408         }
 409 #endif
 410         addr = (const char *)sa + sa_addroffset(sa);
 411         return inet_ntop(sa->sa_family, addr, buf, len);
 412 }
 413
 414 int
 415 sa_cmp(const struct sockaddr *sa1, const struct sockaddr *sa2)
 416 {
 417         socklen_t offset, len;
 418
 419         assert(sa1 != NULL);
 420         assert(sa2 != NULL);
 421
 422         /* Treat AF_UNSPEC as the unspecified address. */
 423         if ((sa1->sa_family == AF_UNSPEC || sa2->sa_family == AF_UNSPEC) &&
 424             sa_is_unspecified(sa1) && sa_is_unspecified(sa2))
 425                 return 0;
 426
 427         if (sa1->sa_family != sa2->sa_family)
 428                 return sa1->sa_family - sa2->sa_family;
 429
 430 #ifdef HAVE_SA_LEN
 431         len = MIN(sa1->sa_len, sa2->sa_len);
 432 #endif
 433
 434         switch (sa1->sa_family) {
 435 #ifdef INET
 436         case AF_INET:
 437                 offset = offsetof(struct sockaddr_in, sin_addr);
 438 #ifdef HAVE_SA_LEN
 439                 len -= offset;
 440                 len = MIN(len, sizeof(struct in_addr));
 441 #else
 442                 len = sizeof(struct in_addr);
 443 #endif
 444                 break;
 445 #endif
 446 #ifdef INET6
 447         case AF_INET6:
 448                 offset = offsetof(struct sockaddr_in6, sin6_addr);
 449 #ifdef HAVE_SA_LEN
 450                 len -= offset;
 451                 len = MIN(len, sizeof(struct in6_addr));
 452 #else
 453                 len = sizeof(struct in6_addr);
 454 #endif
 455                 break;
 456 #endif
 457         default:
 458                 offset = 0;
 459 #ifndef HAVE_SA_LEN
 460                 len = sizeof(struct sockaddr);
 461 #endif
 462                 break;
 463         }
 464
 465         return memcmp((const char *)sa1 + offset,
 466             (const char *)sa2 + offset,
 467             len);
 468 }
 469
 470 #ifdef INET
 471 void
 472 sa_in_init(struct sockaddr *sa, const struct in_addr *addr)
 473 {
 474         struct sockaddr_in *sin;
 475
 476         assert(sa != NULL);
 477         assert(addr != NULL);
 478         sin = satosin(sa);
 479         sin->sin_family = AF_INET;
 480 #ifdef HAVE_SA_LEN
 481         sin->sin_len = sizeof(*sin);
 482 #endif
 483         sin->sin_addr.s_addr = addr->s_addr;
 484 }
 485 #endif
 486
 487 #ifdef INET6
 488 void
 489 sa_in6_init(struct sockaddr *sa, const struct in6_addr *addr)
 490 {
 491         struct sockaddr_in6 *sin6;
 492
 493         assert(sa != NULL);
 494         assert(addr != NULL);
 495         sin6 = satosin6(sa);
 496         sin6->sin6_family = AF_INET6;
 497 #ifdef HAVE_SA_LEN
 498         sin6->sin6_len = sizeof(*sin6);
 499 #endif
 500         memcpy(&sin6->sin6_addr.s6_addr, &addr->s6_addr,
 501             sizeof(sin6->sin6_addr.s6_addr));
 502 }
 503 #endif