src/basic/in-addr-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <arpa/inet.h>
   4 #include <endian.h>
   5 #include <errno.h>
   6 #include <net/if.h>
   7 #include <stdint.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10
  11 #include "alloc-util.h"
  12 #include "errno-util.h"
  13 #include "in-addr-util.h"
  14 #include "macro.h"
  15 #include "parse-util.h"
  16 #include "random-util.h"
  17 #include "string-util.h"
  18 #include "strxcpyx.h"
  19 #include "util.h"
  20
  21 bool in4_addr_is_null(const struct in_addr *a) {
  22         assert(a);
  23
  24         return a->s_addr == 0;
  25 }
  26
  27 int in_addr_is_null(int family, const union in_addr_union *u) {
  28         assert(u);
  29
  30         if (family == AF_INET)
  31                 return in4_addr_is_null(&u->in);
  32
  33         if (family == AF_INET6)
  34                 return IN6_IS_ADDR_UNSPECIFIED(&u->in6);
  35
  36         return -EAFNOSUPPORT;
  37 }
  38
  39 bool in4_addr_is_link_local(const struct in_addr *a) {
  40         assert(a);
  41
  42         return (be32toh(a->s_addr) & UINT32_C(0xFFFF0000)) == (UINT32_C(169) << 24 | UINT32_C(254) << 16);
  43 }
  44
  45 int in_addr_is_link_local(int family, const union in_addr_union *u) {
  46         assert(u);
  47
  48         if (family == AF_INET)
  49                 return in4_addr_is_link_local(&u->in);
  50
  51         if (family == AF_INET6)
  52                 return IN6_IS_ADDR_LINKLOCAL(&u->in6);
  53
  54         return -EAFNOSUPPORT;
  55 }
  56
  57 int in_addr_is_multicast(int family, const union in_addr_union *u) {
  58         assert(u);
  59
  60         if (family == AF_INET)
  61                 return IN_MULTICAST(be32toh(u->in.s_addr));
  62
  63         if (family == AF_INET6)
  64                 return IN6_IS_ADDR_MULTICAST(&u->in6);
  65
  66         return -EAFNOSUPPORT;
  67 }
  68
  69 bool in4_addr_is_localhost(const struct in_addr *a) {
  70         assert(a);
  71
  72         /* All of 127.x.x.x is localhost. */
  73         return (be32toh(a->s_addr) & UINT32_C(0xFF000000)) == UINT32_C(127) << 24;
  74 }
  75
  76 bool in4_addr_is_non_local(const struct in_addr *a) {
  77         /* Whether the address is not null and not localhost.
  78          *
  79          * As such, it is suitable to configure as DNS/NTP server from DHCP. */
  80         return !in4_addr_is_null(a) &&
  81                !in4_addr_is_localhost(a);
  82 }
  83
  84 int in_addr_is_localhost(int family, const union in_addr_union *u) {
  85         assert(u);
  86
  87         if (family == AF_INET)
  88                 return in4_addr_is_localhost(&u->in);
  89
  90         if (family == AF_INET6)
  91                 return IN6_IS_ADDR_LOOPBACK(&u->in6);
  92
  93         return -EAFNOSUPPORT;
  94 }
  95
  96 bool in4_addr_equal(const struct in_addr *a, const struct in_addr *b) {
  97         assert(a);
  98         assert(b);
  99
 100         return a->s_addr == b->s_addr;
 101 }
 102
 103 int in_addr_equal(int family, const union in_addr_union *a, const union in_addr_union *b) {
 104         assert(a);
 105         assert(b);
 106
 107         if (family == AF_INET)
 108                 return in4_addr_equal(&a->in, &b->in);
 109
 110         if (family == AF_INET6)
 111                 return
 112                         a->in6.s6_addr32[0] == b->in6.s6_addr32[0] &&
 113                         a->in6.s6_addr32[1] == b->in6.s6_addr32[1] &&
 114                         a->in6.s6_addr32[2] == b->in6.s6_addr32[2] &&
 115                         a->in6.s6_addr32[3] == b->in6.s6_addr32[3];
 116
 117         return -EAFNOSUPPORT;
 118 }
 119
 120 int in_addr_prefix_intersect(
 121                 int family,
 122                 const union in_addr_union *a,
 123                 unsigned aprefixlen,
 124                 const union in_addr_union *b,
 125                 unsigned bprefixlen) {
 126
 127         unsigned m;
 128
 129         assert(a);
 130         assert(b);
 131
 132         /* Checks whether there are any addresses that are in both
 133          * networks */
 134
 135         m = MIN(aprefixlen, bprefixlen);
 136
 137         if (family == AF_INET) {
 138                 uint32_t x, nm;
 139
 140                 x = be32toh(a->in.s_addr ^ b->in.s_addr);
 141                 nm = (m == 0) ? 0 : 0xFFFFFFFFUL << (32 - m);
 142
 143                 return (x & nm) == 0;
 144         }
 145
 146         if (family == AF_INET6) {
 147                 unsigned i;
 148
 149                 if (m > 128)
 150                         m = 128;
 151
 152                 for (i = 0; i < 16; i++) {
 153                         uint8_t x, nm;
 154
 155                         x = a->in6.s6_addr[i] ^ b->in6.s6_addr[i];
 156
 157                         if (m < 8)
 158                                 nm = 0xFF << (8 - m);
 159                         else
 160                                 nm = 0xFF;
 161
 162                         if ((x & nm) != 0)
 163                                 return 0;
 164
 165                         if (m > 8)
 166                                 m -= 8;
 167                         else
 168                                 m = 0;
 169                 }
 170
 171                 return 1;
 172         }
 173
 174         return -EAFNOSUPPORT;
 175 }
 176
 177 int in_addr_prefix_next(int family, union in_addr_union *u, unsigned prefixlen) {
 178         assert(u);
 179
 180         /* Increases the network part of an address by one. Returns
 181          * positive if that succeeds, or -ERANGE if this overflows. */
 182
 183         return in_addr_prefix_nth(family, u, prefixlen, 1);
 184 }
 185
 186 /*
 187  * Calculates the nth prefix of size prefixlen starting from the address denoted by u.
 188  *
 189  * On success 1 will be returned and the calculated prefix will be available in
 190  * u. In the case nth == 0 the input will be left unchanged and 1 will be returned.
 191  * In case the calculation cannot be performed (invalid prefix length,
 192  * overflows would occur) -ERANGE is returned. If the address family given isn't
 193  * supported -EAFNOSUPPORT will be returned.
 194  *
 195  *
 196  * Examples:
 197  *   - in_addr_prefix_nth(AF_INET, 192.168.0.0, 24, 2), returns 1, writes 192.168.2.0 to u
 198  *   - in_addr_prefix_nth(AF_INET, 192.168.0.0, 24, 0), returns 1, no data written
 199  *   - in_addr_prefix_nth(AF_INET, 255.255.255.0, 24, 1), returns -ERANGE, no data written
 200  *   - in_addr_prefix_nth(AF_INET, 255.255.255.0, 0, 1), returns -ERANGE, no data written
 201  *   - in_addr_prefix_nth(AF_INET6, 2001:db8, 64, 0xff00) returns 1, writes 2001:0db8:0000:ff00:: to u
 202  */
 203 int in_addr_prefix_nth(int family, union in_addr_union *u, unsigned prefixlen, uint64_t nth) {
 204         assert(u);
 205
 206         if (prefixlen <= 0)
 207                 return -ERANGE;
 208
 209         if (nth == 0)
 210                 return 1;
 211
 212         if (family == AF_INET) {
 213                 uint32_t c, n, t;
 214                 if (prefixlen > 32)
 215                         prefixlen = 32;
 216
 217                 c = be32toh(u->in.s_addr);
 218
 219                 t = nth << (32 - prefixlen);
 220
 221                 /* Check for wrap */
 222                 if (c > UINT32_MAX - t)
 223                         return -ERANGE;
 224
 225                 n = c + t;
 226
 227                 n &= UINT32_C(0xFFFFFFFF) << (32 - prefixlen);
 228                 u->in.s_addr = htobe32(n);
 229                 return 1;
 230         }
 231
 232         if (family == AF_INET6) {
 233                 struct in6_addr result = {};
 234                 uint8_t overflow = 0;
 235                 uint64_t delta;  /* this assumes that we only ever have to up to 1<<64 subnets */
 236                 unsigned start_byte = (prefixlen - 1) / 8;
 237
 238                 if (prefixlen > 128)
 239                         prefixlen = 128;
 240
 241                 /* First calculate what we have to add */
 242                 delta = nth << ((128 - prefixlen) % 8);
 243
 244                 for (unsigned i = 16; i > 0; i--) {
 245                         unsigned j = i - 1;
 246                         unsigned d = 0;
 247
 248                         if (j <= start_byte) {
 249                                 int16_t t;
 250
 251                                 d = delta & 0xFF;
 252                                 delta >>= 8;
 253
 254                                 t = u->in6.s6_addr[j] + d + overflow;
 255                                 overflow = t > UINT8_MAX ? t - UINT8_MAX : 0;
 256
 257                                 result.s6_addr[j] = (uint8_t)t;
 258                         } else
 259                                 result.s6_addr[j] = u->in6.s6_addr[j];
 260                 }
 261
 262                 if (overflow || delta != 0)
 263                         return -ERANGE;
 264
 265                 u->in6 = result;
 266                 return 1;
 267         }
 268
 269         return -EAFNOSUPPORT;
 270 }
 271
 272 int in_addr_random_prefix(
 273                 int family,
 274                 union in_addr_union *u,
 275                 unsigned prefixlen_fixed_part,
 276                 unsigned prefixlen) {
 277
 278         assert(u);
 279
 280         /* Random network part of an address by one. */
 281
 282         if (prefixlen <= 0)
 283                 return 0;
 284
 285         if (family == AF_INET) {
 286                 uint32_t c, n;
 287
 288                 if (prefixlen_fixed_part > 32)
 289                         prefixlen_fixed_part = 32;
 290                 if (prefixlen > 32)
 291                         prefixlen = 32;
 292                 if (prefixlen_fixed_part >= prefixlen)
 293                         return -EINVAL;
 294
 295                 c = be32toh(u->in.s_addr);
 296                 c &= ((UINT32_C(1) << prefixlen_fixed_part) - 1) << (32 - prefixlen_fixed_part);
 297
 298                 random_bytes(&n, sizeof(n));
 299                 n &= ((UINT32_C(1) << (prefixlen - prefixlen_fixed_part)) - 1) << (32 - prefixlen);
 300
 301                 u->in.s_addr = htobe32(n | c);
 302                 return 1;
 303         }
 304
 305         if (family == AF_INET6) {
 306                 struct in6_addr n;
 307                 unsigned i, j;
 308
 309                 if (prefixlen_fixed_part > 128)
 310                         prefixlen_fixed_part = 128;
 311                 if (prefixlen > 128)
 312                         prefixlen = 128;
 313                 if (prefixlen_fixed_part >= prefixlen)
 314                         return -EINVAL;
 315
 316                 random_bytes(&n, sizeof(n));
 317
 318                 for (i = 0; i < 16; i++) {
 319                         uint8_t mask_fixed_part = 0, mask = 0;
 320
 321                         if (i < (prefixlen_fixed_part + 7) / 8) {
 322                                 if (i < prefixlen_fixed_part / 8)
 323                                         mask_fixed_part = 0xffu;
 324                                 else {
 325                                         j = prefixlen_fixed_part % 8;
 326                                         mask_fixed_part = ((UINT8_C(1) << (j + 1)) - 1) << (8 - j);
 327                                 }
 328                         }
 329
 330                         if (i < (prefixlen + 7) / 8) {
 331                                 if (i < prefixlen / 8)
 332                                         mask = 0xffu ^ mask_fixed_part;
 333                                 else {
 334                                         j = prefixlen % 8;
 335                                         mask = (((UINT8_C(1) << (j + 1)) - 1) << (8 - j)) ^ mask_fixed_part;
 336                                 }
 337                         }
 338
 339                         u->in6.s6_addr[i] &= mask_fixed_part;
 340                         u->in6.s6_addr[i] |= n.s6_addr[i] & mask;
 341                 }
 342
 343                 return 1;
 344         }
 345
 346         return -EAFNOSUPPORT;
 347 }
 348
 349 int in_addr_to_string(int family, const union in_addr_union *u, char **ret) {
 350         _cleanup_free_ char *x = NULL;
 351         size_t l;
 352
 353         assert(u);
 354         assert(ret);
 355
 356         if (family == AF_INET)
 357                 l = INET_ADDRSTRLEN;
 358         else if (family == AF_INET6)
 359                 l = INET6_ADDRSTRLEN;
 360         else
 361                 return -EAFNOSUPPORT;
 362
 363         x = new(char, l);
 364         if (!x)
 365                 return -ENOMEM;
 366
 367         errno = 0;
 368         if (!inet_ntop(family, u, x, l))
 369                 return errno_or_else(EINVAL);
 370
 371         *ret = TAKE_PTR(x);
 372         return 0;
 373 }
 374
 375 int in_addr_prefix_to_string(int family, const union in_addr_union *u, unsigned prefixlen, char **ret) {
 376         _cleanup_free_ char *x = NULL;
 377         char *p;
 378         size_t l;
 379
 380         assert(u);
 381         assert(ret);
 382
 383         if (family == AF_INET)
 384                 l = INET_ADDRSTRLEN + 3;
 385         else if (family == AF_INET6)
 386                 l = INET6_ADDRSTRLEN + 4;
 387         else
 388                 return -EAFNOSUPPORT;
 389
 390         if (prefixlen > FAMILY_ADDRESS_SIZE(family) * 8)
 391                 return -EINVAL;
 392
 393         x = new(char, l);
 394         if (!x)
 395                 return -ENOMEM;
 396
 397         errno = 0;
 398         if (!inet_ntop(family, u, x, l))
 399                 return errno_or_else(EINVAL);
 400
 401         p = x + strlen(x);
 402         l -= strlen(x);
 403         (void) strpcpyf(&p, l, "/%u", prefixlen);
 404
 405         *ret = TAKE_PTR(x);
 406         return 0;
 407 }
 408
 409 int in_addr_ifindex_to_string(int family, const union in_addr_union *u, int ifindex, char **ret) {
 410         _cleanup_free_ char *x = NULL;
 411         size_t l;
 412         int r;
 413
 414         assert(u);
 415         assert(ret);
 416
 417         /* Much like in_addr_to_string(), but optionally appends the zone interface index to the address, to properly
 418          * handle IPv6 link-local addresses. */
 419
 420         if (family != AF_INET6)
 421                 goto fallback;
 422         if (ifindex <= 0)
 423                 goto fallback;
 424
 425         r = in_addr_is_link_local(family, u);
 426         if (r < 0)
 427                 return r;
 428         if (r == 0)
 429                 goto fallback;
 430
 431         l = INET6_ADDRSTRLEN + 1 + DECIMAL_STR_MAX(ifindex) + 1;
 432         x = new(char, l);
 433         if (!x)
 434                 return -ENOMEM;
 435
 436         errno = 0;
 437         if (!inet_ntop(family, u, x, l))
 438                 return errno_or_else(EINVAL);
 439
 440         sprintf(strchr(x, 0), "%%%i", ifindex);
 441
 442         *ret = TAKE_PTR(x);
 443         return 0;
 444
 445 fallback:
 446         return in_addr_to_string(family, u, ret);
 447 }
 448
 449 int in_addr_port_ifindex_name_to_string(int family, const union in_addr_union *u, uint16_t port, int ifindex, const char *server_name, char **ret) {
 450         _cleanup_free_ char *ip_str = NULL, *x = NULL;
 451         int r;
 452
 453         assert(IN_SET(family, AF_INET, AF_INET6));
 454         assert(u);
 455         assert(ret);
 456
 457         /* Much like in_addr_to_string(), but optionally appends the zone interface index to the address, to properly
 458          * handle IPv6 link-local addresses. */
 459
 460         r = in_addr_to_string(family, u, &ip_str);
 461         if (r < 0)
 462                 return r;
 463
 464         if (family == AF_INET6) {
 465                 r = in_addr_is_link_local(family, u);
 466                 if (r < 0)
 467                         return r;
 468                 if (r == 0)
 469                         ifindex = 0;
 470         } else
 471                 ifindex = 0; /* For IPv4 address, ifindex is always ignored. */
 472
 473         if (port == 0 && ifindex == 0 && isempty(server_name)) {
 474                 *ret = TAKE_PTR(ip_str);
 475                 return 0;
 476         }
 477
 478         const char *separator = isempty(server_name) ? "" : "#";
 479         server_name = strempty(server_name);
 480
 481         if (port > 0) {
 482                 if (family == AF_INET6) {
 483                         if (ifindex > 0)
 484                                 r = asprintf(&x, "[%s]:%"PRIu16"%%%i%s%s", ip_str, port, ifindex, separator, server_name);
 485                         else
 486                                 r = asprintf(&x, "[%s]:%"PRIu16"%s%s", ip_str, port, separator, server_name);
 487                 } else
 488                         r = asprintf(&x, "%s:%"PRIu16"%s%s", ip_str, port, separator, server_name);
 489         } else {
 490                 if (ifindex > 0)
 491                         r = asprintf(&x, "%s%%%i%s%s", ip_str, ifindex, separator, server_name);
 492                 else {
 493                         x = strjoin(ip_str, separator, server_name);
 494                         r = x ? 0 : -ENOMEM;
 495                 }
 496         }
 497         if (r < 0)
 498                 return -ENOMEM;
 499
 500         *ret = TAKE_PTR(x);
 501         return 0;
 502 }
 503
 504 int in_addr_from_string(int family, const char *s, union in_addr_union *ret) {
 505         union in_addr_union buffer;
 506         assert(s);
 507
 508         if (!IN_SET(family, AF_INET, AF_INET6))
 509                 return -EAFNOSUPPORT;
 510
 511         errno = 0;
 512         if (inet_pton(family, s, ret ?: &buffer) <= 0)
 513                 return errno_or_else(EINVAL);
 514
 515         return 0;
 516 }
 517
 518 int in_addr_from_string_auto(const char *s, int *ret_family, union in_addr_union *ret) {
 519         int r;
 520
 521         assert(s);
 522
 523         r = in_addr_from_string(AF_INET, s, ret);
 524         if (r >= 0) {
 525                 if (ret_family)
 526                         *ret_family = AF_INET;
 527                 return 0;
 528         }
 529
 530         r = in_addr_from_string(AF_INET6, s, ret);
 531         if (r >= 0) {
 532                 if (ret_family)
 533                         *ret_family = AF_INET6;
 534                 return 0;
 535         }
 536
 537         return -EINVAL;
 538 }
 539
 540 unsigned char in4_addr_netmask_to_prefixlen(const struct in_addr *addr) {
 541         assert(addr);
 542
 543         return 32U - u32ctz(be32toh(addr->s_addr));
 544 }
 545
 546 struct in_addr* in4_addr_prefixlen_to_netmask(struct in_addr *addr, unsigned char prefixlen) {
 547         assert(addr);
 548         assert(prefixlen <= 32);
 549
 550         /* Shifting beyond 32 is not defined, handle this specially. */
 551         if (prefixlen == 0)
 552                 addr->s_addr = 0;
 553         else
 554                 addr->s_addr = htobe32((0xffffffff << (32 - prefixlen)) & 0xffffffff);
 555
 556         return addr;
 557 }
 558
 559 int in4_addr_default_prefixlen(const struct in_addr *addr, unsigned char *prefixlen) {
 560         uint8_t msb_octet = *(uint8_t*) addr;
 561
 562         /* addr may not be aligned, so make sure we only access it byte-wise */
 563
 564         assert(addr);
 565         assert(prefixlen);
 566
 567         if (msb_octet < 128)
 568                 /* class A, leading bits: 0 */
 569                 *prefixlen = 8;
 570         else if (msb_octet < 192)
 571                 /* class B, leading bits 10 */
 572                 *prefixlen = 16;
 573         else if (msb_octet < 224)
 574                 /* class C, leading bits 110 */
 575                 *prefixlen = 24;
 576         else
 577                 /* class D or E, no default prefixlen */
 578                 return -ERANGE;
 579
 580         return 0;
 581 }
 582
 583 int in4_addr_default_subnet_mask(const struct in_addr *addr, struct in_addr *mask) {
 584         unsigned char prefixlen;
 585         int r;
 586
 587         assert(addr);
 588         assert(mask);
 589
 590         r = in4_addr_default_prefixlen(addr, &prefixlen);
 591         if (r < 0)
 592                 return r;
 593
 594         in4_addr_prefixlen_to_netmask(mask, prefixlen);
 595         return 0;
 596 }
 597
 598 int in_addr_mask(int family, union in_addr_union *addr, unsigned char prefixlen) {
 599         assert(addr);
 600
 601         if (family == AF_INET) {
 602                 struct in_addr mask;
 603
 604                 if (!in4_addr_prefixlen_to_netmask(&mask, prefixlen))
 605                         return -EINVAL;
 606
 607                 addr->in.s_addr &= mask.s_addr;
 608                 return 0;
 609         }
 610
 611         if (family == AF_INET6) {
 612                 unsigned i;
 613
 614                 for (i = 0; i < 16; i++) {
 615                         uint8_t mask;
 616
 617                         if (prefixlen >= 8) {
 618                                 mask = 0xFF;
 619                                 prefixlen -= 8;
 620                         } else {
 621                                 mask = 0xFF << (8 - prefixlen);
 622                                 prefixlen = 0;
 623                         }
 624
 625                         addr->in6.s6_addr[i] &= mask;
 626                 }
 627
 628                 return 0;
 629         }
 630
 631         return -EAFNOSUPPORT;
 632 }
 633
 634 int in_addr_prefix_covers(int family,
 635                           const union in_addr_union *prefix,
 636                           unsigned char prefixlen,
 637                           const union in_addr_union *address) {
 638
 639         union in_addr_union masked_prefix, masked_address;
 640         int r;
 641
 642         assert(prefix);
 643         assert(address);
 644
 645         masked_prefix = *prefix;
 646         r = in_addr_mask(family, &masked_prefix, prefixlen);
 647         if (r < 0)
 648                 return r;
 649
 650         masked_address = *address;
 651         r = in_addr_mask(family, &masked_address, prefixlen);
 652         if (r < 0)
 653                 return r;
 654
 655         return in_addr_equal(family, &masked_prefix, &masked_address);
 656 }
 657
 658 int in_addr_parse_prefixlen(int family, const char *p, unsigned char *ret) {
 659         uint8_t u;
 660         int r;
 661
 662         if (!IN_SET(family, AF_INET, AF_INET6))
 663                 return -EAFNOSUPPORT;
 664
 665         r = safe_atou8(p, &u);
 666         if (r < 0)
 667                 return r;
 668
 669         if (u > FAMILY_ADDRESS_SIZE(family) * 8)
 670                 return -ERANGE;
 671
 672         *ret = u;
 673         return 0;
 674 }
 675
 676 int in_addr_prefix_from_string(
 677                 const char *p,
 678                 int family,
 679                 union in_addr_union *ret_prefix,
 680                 unsigned char *ret_prefixlen) {
 681
 682         _cleanup_free_ char *str = NULL;
 683         union in_addr_union buffer;
 684         const char *e, *l;
 685         unsigned char k;
 686         int r;
 687
 688         assert(p);
 689
 690         if (!IN_SET(family, AF_INET, AF_INET6))
 691                 return -EAFNOSUPPORT;
 692
 693         e = strchr(p, '/');
 694         if (e) {
 695                 str = strndup(p, e - p);
 696                 if (!str)
 697                         return -ENOMEM;
 698
 699                 l = str;
 700         } else
 701                 l = p;
 702
 703         r = in_addr_from_string(family, l, &buffer);
 704         if (r < 0)
 705                 return r;
 706
 707         if (e) {
 708                 r = in_addr_parse_prefixlen(family, e+1, &k);
 709                 if (r < 0)
 710                         return r;
 711         } else
 712                 k = FAMILY_ADDRESS_SIZE(family) * 8;
 713
 714         if (ret_prefix)
 715                 *ret_prefix = buffer;
 716         if (ret_prefixlen)
 717                 *ret_prefixlen = k;
 718
 719         return 0;
 720 }
 721
 722 int in_addr_prefix_from_string_auto_internal(
 723                 const char *p,
 724                 InAddrPrefixLenMode mode,
 725                 int *ret_family,
 726                 union in_addr_union *ret_prefix,
 727                 unsigned char *ret_prefixlen) {
 728
 729         _cleanup_free_ char *str = NULL;
 730         union in_addr_union buffer;
 731         const char *e, *l;
 732         unsigned char k;
 733         int family, r;
 734
 735         assert(p);
 736
 737         e = strchr(p, '/');
 738         if (e) {
 739                 str = strndup(p, e - p);
 740                 if (!str)
 741                         return -ENOMEM;
 742
 743                 l = str;
 744         } else
 745                 l = p;
 746
 747         r = in_addr_from_string_auto(l, &family, &buffer);
 748         if (r < 0)
 749                 return r;
 750
 751         if (e) {
 752                 r = in_addr_parse_prefixlen(family, e+1, &k);
 753                 if (r < 0)
 754                         return r;
 755         } else
 756                 switch (mode) {
 757                 case PREFIXLEN_FULL:
 758                         k = FAMILY_ADDRESS_SIZE(family) * 8;
 759                         break;
 760                 case PREFIXLEN_REFUSE:
 761                         return -ENOANO; /* To distinguish this error from others. */
 762                 case PREFIXLEN_LEGACY:
 763                         if (family == AF_INET) {
 764                                 r = in4_addr_default_prefixlen(&buffer.in, &k);
 765                                 if (r < 0)
 766                                         return r;
 767                         } else
 768                                 k = 0;
 769                         break;
 770                 default:
 771                         assert_not_reached("Invalid prefixlen mode");
 772                 }
 773
 774         if (ret_family)
 775                 *ret_family = family;
 776         if (ret_prefix)
 777                 *ret_prefix = buffer;
 778         if (ret_prefixlen)
 779                 *ret_prefixlen = k;
 780
 781         return 0;
 782
 783 }
 784
 785 static void in_addr_data_hash_func(const struct in_addr_data *a, struct siphash *state) {
 786         siphash24_compress(&a->family, sizeof(a->family), state);
 787         siphash24_compress(&a->address, FAMILY_ADDRESS_SIZE(a->family), state);
 788 }
 789
 790 static int in_addr_data_compare_func(const struct in_addr_data *x, const struct in_addr_data *y) {
 791         int r;
 792
 793         r = CMP(x->family, y->family);
 794         if (r != 0)
 795                 return r;
 796
 797         return memcmp(&x->address, &y->address, FAMILY_ADDRESS_SIZE(x->family));
 798 }
 799
 800 DEFINE_HASH_OPS(in_addr_data_hash_ops, struct in_addr_data, in_addr_data_hash_func, in_addr_data_compare_func);
 801
 802 static void in6_addr_hash_func(const struct in6_addr *addr, struct siphash *state) {
 803         assert(addr);
 804
 805         siphash24_compress(addr, sizeof(*addr), state);
 806 }
 807
 808 static int in6_addr_compare_func(const struct in6_addr *a, const struct in6_addr *b) {
 809         return memcmp(a, b, sizeof(*a));
 810 }
 811
 812 DEFINE_HASH_OPS(in6_addr_hash_ops, struct in6_addr, in6_addr_hash_func, in6_addr_compare_func);