src/basic/in-addr-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2014 Lennart Poettering
   4 ***/
   5
   6 #include <arpa/inet.h>
   7 #include <endian.h>
   8 #include <errno.h>
   9 #include <net/if.h>
  10 #include <stdint.h>
  11 #include <stdlib.h>
  12
  13 #include "alloc-util.h"
  14 #include "in-addr-util.h"
  15 #include "macro.h"
  16 #include "parse-util.h"
  17 #include "util.h"
  18
  19 bool in4_addr_is_null(const struct in_addr *a) {
  20         assert(a);
  21
  22         return a->s_addr == 0;
  23 }
  24
  25 int in_addr_is_null(int family, const union in_addr_union *u) {
  26         assert(u);
  27
  28         if (family == AF_INET)
  29                 return in4_addr_is_null(&u->in);
  30
  31         if (family == AF_INET6)
  32                 return IN6_IS_ADDR_UNSPECIFIED(&u->in6);
  33
  34         return -EAFNOSUPPORT;
  35 }
  36
  37 bool in4_addr_is_link_local(const struct in_addr *a) {
  38         assert(a);
  39
  40         return (be32toh(a->s_addr) & UINT32_C(0xFFFF0000)) == (UINT32_C(169) << 24 | UINT32_C(254) << 16);
  41 }
  42
  43 int in_addr_is_link_local(int family, const union in_addr_union *u) {
  44         assert(u);
  45
  46         if (family == AF_INET)
  47                 return in4_addr_is_link_local(&u->in);
  48
  49         if (family == AF_INET6)
  50                 return IN6_IS_ADDR_LINKLOCAL(&u->in6);
  51
  52         return -EAFNOSUPPORT;
  53 }
  54
  55 int in_addr_is_multicast(int family, const union in_addr_union *u) {
  56         assert(u);
  57
  58         if (family == AF_INET)
  59                 return IN_MULTICAST(be32toh(u->in.s_addr));
  60
  61         if (family == AF_INET6)
  62                 return IN6_IS_ADDR_MULTICAST(&u->in6);
  63
  64         return -EAFNOSUPPORT;
  65 }
  66
  67 bool in4_addr_is_localhost(const struct in_addr *a) {
  68         assert(a);
  69
  70         /* All of 127.x.x.x is localhost. */
  71         return (be32toh(a->s_addr) & UINT32_C(0xFF000000)) == UINT32_C(127) << 24;
  72 }
  73
  74 int in_addr_is_localhost(int family, const union in_addr_union *u) {
  75         assert(u);
  76
  77         if (family == AF_INET)
  78                 return in4_addr_is_localhost(&u->in);
  79
  80         if (family == AF_INET6)
  81                 return IN6_IS_ADDR_LOOPBACK(&u->in6);
  82
  83         return -EAFNOSUPPORT;
  84 }
  85
  86 int in_addr_equal(int family, const union in_addr_union *a, const union in_addr_union *b) {
  87         assert(a);
  88         assert(b);
  89
  90         if (family == AF_INET)
  91                 return a->in.s_addr == b->in.s_addr;
  92
  93         if (family == AF_INET6)
  94                 return
  95                         a->in6.s6_addr32[0] == b->in6.s6_addr32[0] &&
  96                         a->in6.s6_addr32[1] == b->in6.s6_addr32[1] &&
  97                         a->in6.s6_addr32[2] == b->in6.s6_addr32[2] &&
  98                         a->in6.s6_addr32[3] == b->in6.s6_addr32[3];
  99
 100         return -EAFNOSUPPORT;
 101 }
 102
 103 int in_addr_prefix_intersect(
 104                 int family,
 105                 const union in_addr_union *a,
 106                 unsigned aprefixlen,
 107                 const union in_addr_union *b,
 108                 unsigned bprefixlen) {
 109
 110         unsigned m;
 111
 112         assert(a);
 113         assert(b);
 114
 115         /* Checks whether there are any addresses that are in both
 116          * networks */
 117
 118         m = MIN(aprefixlen, bprefixlen);
 119
 120         if (family == AF_INET) {
 121                 uint32_t x, nm;
 122
 123                 x = be32toh(a->in.s_addr ^ b->in.s_addr);
 124                 nm = (m == 0) ? 0 : 0xFFFFFFFFUL << (32 - m);
 125
 126                 return (x & nm) == 0;
 127         }
 128
 129         if (family == AF_INET6) {
 130                 unsigned i;
 131
 132                 if (m > 128)
 133                         m = 128;
 134
 135                 for (i = 0; i < 16; i++) {
 136                         uint8_t x, nm;
 137
 138                         x = a->in6.s6_addr[i] ^ b->in6.s6_addr[i];
 139
 140                         if (m < 8)
 141                                 nm = 0xFF << (8 - m);
 142                         else
 143                                 nm = 0xFF;
 144
 145                         if ((x & nm) != 0)
 146                                 return 0;
 147
 148                         if (m > 8)
 149                                 m -= 8;
 150                         else
 151                                 m = 0;
 152                 }
 153
 154                 return 1;
 155         }
 156
 157         return -EAFNOSUPPORT;
 158 }
 159
 160 int in_addr_prefix_next(int family, union in_addr_union *u, unsigned prefixlen) {
 161         assert(u);
 162
 163         /* Increases the network part of an address by one. Returns
 164          * positive it that succeeds, or 0 if this overflows. */
 165
 166         if (prefixlen <= 0)
 167                 return 0;
 168
 169         if (family == AF_INET) {
 170                 uint32_t c, n;
 171
 172                 if (prefixlen > 32)
 173                         prefixlen = 32;
 174
 175                 c = be32toh(u->in.s_addr);
 176                 n = c + (1UL << (32 - prefixlen));
 177                 if (n < c)
 178                         return 0;
 179                 n &= 0xFFFFFFFFUL << (32 - prefixlen);
 180
 181                 u->in.s_addr = htobe32(n);
 182                 return 1;
 183         }
 184
 185         if (family == AF_INET6) {
 186                 struct in6_addr add = {}, result;
 187                 uint8_t overflow = 0;
 188                 unsigned i;
 189
 190                 if (prefixlen > 128)
 191                         prefixlen = 128;
 192
 193                 /* First calculate what we have to add */
 194                 add.s6_addr[(prefixlen-1) / 8] = 1 << (7 - (prefixlen-1) % 8);
 195
 196                 for (i = 16; i > 0; i--) {
 197                         unsigned j = i - 1;
 198
 199                         result.s6_addr[j] = u->in6.s6_addr[j] + add.s6_addr[j] + overflow;
 200                         overflow = (result.s6_addr[j] < u->in6.s6_addr[j]);
 201                 }
 202
 203                 if (overflow)
 204                         return 0;
 205
 206                 u->in6 = result;
 207                 return 1;
 208         }
 209
 210         return -EAFNOSUPPORT;
 211 }
 212
 213 int in_addr_to_string(int family, const union in_addr_union *u, char **ret) {
 214         char *x;
 215         size_t l;
 216
 217         assert(u);
 218         assert(ret);
 219
 220         if (family == AF_INET)
 221                 l = INET_ADDRSTRLEN;
 222         else if (family == AF_INET6)
 223                 l = INET6_ADDRSTRLEN;
 224         else
 225                 return -EAFNOSUPPORT;
 226
 227         x = new(char, l);
 228         if (!x)
 229                 return -ENOMEM;
 230
 231         errno = 0;
 232         if (!inet_ntop(family, u, x, l)) {
 233                 free(x);
 234                 return errno > 0 ? -errno : -EINVAL;
 235         }
 236
 237         *ret = x;
 238         return 0;
 239 }
 240
 241 int in_addr_ifindex_to_string(int family, const union in_addr_union *u, int ifindex, char **ret) {
 242         size_t l;
 243         char *x;
 244         int r;
 245
 246         assert(u);
 247         assert(ret);
 248
 249         /* Much like in_addr_to_string(), but optionally appends the zone interface index to the address, to properly
 250          * handle IPv6 link-local addresses. */
 251
 252         if (family != AF_INET6)
 253                 goto fallback;
 254         if (ifindex <= 0)
 255                 goto fallback;
 256
 257         r = in_addr_is_link_local(family, u);
 258         if (r < 0)
 259                 return r;
 260         if (r == 0)
 261                 goto fallback;
 262
 263         l = INET6_ADDRSTRLEN + 1 + DECIMAL_STR_MAX(ifindex) + 1;
 264         x = new(char, l);
 265         if (!x)
 266                 return -ENOMEM;
 267
 268         errno = 0;
 269         if (!inet_ntop(family, u, x, l)) {
 270                 free(x);
 271                 return errno > 0 ? -errno : -EINVAL;
 272         }
 273
 274         sprintf(strchr(x, 0), "%%%i", ifindex);
 275         *ret = x;
 276
 277         return 0;
 278
 279 fallback:
 280         return in_addr_to_string(family, u, ret);
 281 }
 282
 283 int in_addr_from_string(int family, const char *s, union in_addr_union *ret) {
 284         union in_addr_union buffer;
 285         assert(s);
 286
 287         if (!IN_SET(family, AF_INET, AF_INET6))
 288                 return -EAFNOSUPPORT;
 289
 290         errno = 0;
 291         if (inet_pton(family, s, ret ?: &buffer) <= 0)
 292                 return errno > 0 ? -errno : -EINVAL;
 293
 294         return 0;
 295 }
 296
 297 int in_addr_from_string_auto(const char *s, int *ret_family, union in_addr_union *ret) {
 298         int r;
 299
 300         assert(s);
 301
 302         r = in_addr_from_string(AF_INET, s, ret);
 303         if (r >= 0) {
 304                 if (ret_family)
 305                         *ret_family = AF_INET;
 306                 return 0;
 307         }
 308
 309         r = in_addr_from_string(AF_INET6, s, ret);
 310         if (r >= 0) {
 311                 if (ret_family)
 312                         *ret_family = AF_INET6;
 313                 return 0;
 314         }
 315
 316         return -EINVAL;
 317 }
 318
 319 int in_addr_ifindex_from_string_auto(const char *s, int *family, union in_addr_union *ret, int *ifindex) {
 320         const char *suffix;
 321         int r, ifi = 0;
 322
 323         assert(s);
 324         assert(family);
 325         assert(ret);
 326
 327         /* Similar to in_addr_from_string_auto() but also parses an optionally appended IPv6 zone suffix ("scope id")
 328          * if one is found. */
 329
 330         suffix = strchr(s, '%');
 331         if (suffix) {
 332
 333                 if (ifindex) {
 334                         /* If we shall return the interface index, try to parse it */
 335                         r = parse_ifindex(suffix + 1, &ifi);
 336                         if (r < 0) {
 337                                 unsigned u;
 338
 339                                 u = if_nametoindex(suffix + 1);
 340                                 if (u <= 0)
 341                                         return -errno;
 342
 343                                 ifi = (int) u;
 344                         }
 345                 }
 346
 347                 s = strndupa(s, suffix - s);
 348         }
 349
 350         r = in_addr_from_string_auto(s, family, ret);
 351         if (r < 0)
 352                 return r;
 353
 354         if (ifindex)
 355                 *ifindex = ifi;
 356
 357         return r;
 358 }
 359
 360 unsigned char in4_addr_netmask_to_prefixlen(const struct in_addr *addr) {
 361         assert(addr);
 362
 363         return 32 - u32ctz(be32toh(addr->s_addr));
 364 }
 365
 366 struct in_addr* in4_addr_prefixlen_to_netmask(struct in_addr *addr, unsigned char prefixlen) {
 367         assert(addr);
 368         assert(prefixlen <= 32);
 369
 370         /* Shifting beyond 32 is not defined, handle this specially. */
 371         if (prefixlen == 0)
 372                 addr->s_addr = 0;
 373         else
 374                 addr->s_addr = htobe32((0xffffffff << (32 - prefixlen)) & 0xffffffff);
 375
 376         return addr;
 377 }
 378
 379 int in4_addr_default_prefixlen(const struct in_addr *addr, unsigned char *prefixlen) {
 380         uint8_t msb_octet = *(uint8_t*) addr;
 381
 382         /* addr may not be aligned, so make sure we only access it byte-wise */
 383
 384         assert(addr);
 385         assert(prefixlen);
 386
 387         if (msb_octet < 128)
 388                 /* class A, leading bits: 0 */
 389                 *prefixlen = 8;
 390         else if (msb_octet < 192)
 391                 /* class B, leading bits 10 */
 392                 *prefixlen = 16;
 393         else if (msb_octet < 224)
 394                 /* class C, leading bits 110 */
 395                 *prefixlen = 24;
 396         else
 397                 /* class D or E, no default prefixlen */
 398                 return -ERANGE;
 399
 400         return 0;
 401 }
 402
 403 int in4_addr_default_subnet_mask(const struct in_addr *addr, struct in_addr *mask) {
 404         unsigned char prefixlen;
 405         int r;
 406
 407         assert(addr);
 408         assert(mask);
 409
 410         r = in4_addr_default_prefixlen(addr, &prefixlen);
 411         if (r < 0)
 412                 return r;
 413
 414         in4_addr_prefixlen_to_netmask(mask, prefixlen);
 415         return 0;
 416 }
 417
 418 int in_addr_mask(int family, union in_addr_union *addr, unsigned char prefixlen) {
 419         assert(addr);
 420
 421         if (family == AF_INET) {
 422                 struct in_addr mask;
 423
 424                 if (!in4_addr_prefixlen_to_netmask(&mask, prefixlen))
 425                         return -EINVAL;
 426
 427                 addr->in.s_addr &= mask.s_addr;
 428                 return 0;
 429         }
 430
 431         if (family == AF_INET6) {
 432                 unsigned i;
 433
 434                 for (i = 0; i < 16; i++) {
 435                         uint8_t mask;
 436
 437                         if (prefixlen >= 8) {
 438                                 mask = 0xFF;
 439                                 prefixlen -= 8;
 440                         } else {
 441                                 mask = 0xFF << (8 - prefixlen);
 442                                 prefixlen = 0;
 443                         }
 444
 445                         addr->in6.s6_addr[i] &= mask;
 446                 }
 447
 448                 return 0;
 449         }
 450
 451         return -EAFNOSUPPORT;
 452 }
 453
 454 int in_addr_prefix_covers(int family,
 455                           const union in_addr_union *prefix,
 456                           unsigned char prefixlen,
 457                           const union in_addr_union *address) {
 458
 459         union in_addr_union masked_prefix, masked_address;
 460         int r;
 461
 462         assert(prefix);
 463         assert(address);
 464
 465         masked_prefix = *prefix;
 466         r = in_addr_mask(family, &masked_prefix, prefixlen);
 467         if (r < 0)
 468                 return r;
 469
 470         masked_address = *address;
 471         r = in_addr_mask(family, &masked_address, prefixlen);
 472         if (r < 0)
 473                 return r;
 474
 475         return in_addr_equal(family, &masked_prefix, &masked_address);
 476 }
 477
 478 int in_addr_parse_prefixlen(int family, const char *p, unsigned char *ret) {
 479         uint8_t u;
 480         int r;
 481
 482         if (!IN_SET(family, AF_INET, AF_INET6))
 483                 return -EAFNOSUPPORT;
 484
 485         r = safe_atou8(p, &u);
 486         if (r < 0)
 487                 return r;
 488
 489         if (u > FAMILY_ADDRESS_SIZE(family) * 8)
 490                 return -ERANGE;
 491
 492         *ret = u;
 493         return 0;
 494 }
 495
 496 int in_addr_prefix_from_string(
 497                 const char *p,
 498                 int family,
 499                 union in_addr_union *ret_prefix,
 500                 unsigned char *ret_prefixlen) {
 501
 502         union in_addr_union buffer;
 503         const char *e, *l;
 504         unsigned char k;
 505         int r;
 506
 507         assert(p);
 508
 509         if (!IN_SET(family, AF_INET, AF_INET6))
 510                 return -EAFNOSUPPORT;
 511
 512         e = strchr(p, '/');
 513         if (e)
 514                 l = strndupa(p, e - p);
 515         else
 516                 l = p;
 517
 518         r = in_addr_from_string(family, l, &buffer);
 519         if (r < 0)
 520                 return r;
 521
 522         if (e) {
 523                 r = in_addr_parse_prefixlen(family, e+1, &k);
 524                 if (r < 0)
 525                         return r;
 526         } else
 527                 k = FAMILY_ADDRESS_SIZE(family) * 8;
 528
 529         if (ret_prefix)
 530                 *ret_prefix = buffer;
 531         if (ret_prefixlen)
 532                 *ret_prefixlen = k;
 533
 534         return 0;
 535 }
 536
 537 int in_addr_prefix_from_string_auto(
 538                 const char *p,
 539                 int *ret_family,
 540                 union in_addr_union *ret_prefix,
 541                 unsigned char *ret_prefixlen) {
 542
 543         union in_addr_union buffer;
 544         const char *e, *l;
 545         unsigned char k;
 546         int family, r;
 547
 548         assert(p);
 549
 550         e = strchr(p, '/');
 551         if (e)
 552                 l = strndupa(p, e - p);
 553         else
 554                 l = p;
 555
 556         r = in_addr_from_string_auto(l, &family, &buffer);
 557         if (r < 0)
 558                 return r;
 559
 560         if (e) {
 561                 r = in_addr_parse_prefixlen(family, e+1, &k);
 562                 if (r < 0)
 563                         return r;
 564         } else
 565                 k = FAMILY_ADDRESS_SIZE(family) * 8;
 566
 567         if (ret_family)
 568                 *ret_family = family;
 569         if (ret_prefix)
 570                 *ret_prefix = buffer;
 571         if (ret_prefixlen)
 572                 *ret_prefixlen = k;
 573
 574         return 0;
 575
 576 }