lib/prefix.c

   1 /*
   2  * Prefix related functions.
   3  * Copyright (C) 1997, 98, 99 Kunihiro Ishiguro
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2, or (at your option) any
  10  * later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with GNU Zebra; see the file COPYING.  If not, write to the Free
  19  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  20  * 02111-1307, USA.
  21  */
  22
  23 #include <zebra.h>
  24
  25 #include "prefix.h"
  26 #include "vty.h"
  27 #include "sockunion.h"
  28 #include "memory.h"
  29 #include "log.h"
  30 \f
  31 /* Maskbit. */
  32 static u_char maskbit[] = {0x00, 0x80, 0xc0, 0xe0, 0xf0,
  33                                  0xf8, 0xfc, 0xfe, 0xff};
  34
  35 /* Number of bits in prefix type. */
  36 #ifndef PNBBY
  37 #define PNBBY 8
  38 #endif /* PNBBY */
  39
  40 #define MASKBIT(offset)  ((0xff << (PNBBY - (offset))) & 0xff)
  41
  42 /* Address Famiy Identifier to Address Family converter. */
  43 int
  44 afi2family (int afi)
  45 {
  46   if (afi == AFI_IP)
  47     return AF_INET;
  48 #ifdef HAVE_IPV6
  49   else if (afi == AFI_IP6)
  50     return AF_INET6;
  51 #endif /* HAVE_IPV6 */
  52   return 0;
  53 }
  54
  55 int
  56 family2afi (int family)
  57 {
  58   if (family == AF_INET)
  59     return AFI_IP;
  60 #ifdef HAVE_IPV6
  61   else if (family == AF_INET6)
  62     return AFI_IP6;
  63 #endif /* HAVE_IPV6 */
  64   return 0;
  65 }
  66
  67 /* If n includes p prefix then return 1 else return 0. */
  68 int
  69 prefix_match (const struct prefix *n, const struct prefix *p)
  70 {
  71   int offset;
  72   int shift;
  73
  74   /* Set both prefix's head pointer. */
  75   const u_char *np = (const u_char *)&n->u.prefix;
  76   const u_char *pp = (const u_char *)&p->u.prefix;
  77
  78   /* If n's prefix is longer than p's one return 0. */
  79   if (n->prefixlen > p->prefixlen)
  80     return 0;
  81
  82   offset = n->prefixlen / PNBBY;
  83   shift =  n->prefixlen % PNBBY;
  84
  85   if (shift)
  86     if (maskbit[shift] & (np[offset] ^ pp[offset]))
  87       return 0;
  88
  89   while (offset--)
  90     if (np[offset] != pp[offset])
  91       return 0;
  92   return 1;
  93 }
  94
  95 /* Copy prefix from src to dest. */
  96 void
  97 prefix_copy (struct prefix *dest, const struct prefix *src)
  98 {
  99   dest->family = src->family;
 100   dest->prefixlen = src->prefixlen;
 101
 102   if (src->family == AF_INET)
 103     dest->u.prefix4 = src->u.prefix4;
 104 #ifdef HAVE_IPV6
 105   else if (src->family == AF_INET6)
 106     dest->u.prefix6 = src->u.prefix6;
 107 #endif /* HAVE_IPV6 */
 108   else if (src->family == AF_UNSPEC)
 109     {
 110       dest->u.lp.id = src->u.lp.id;
 111       dest->u.lp.adv_router = src->u.lp.adv_router;
 112     }
 113   else
 114     {
 115       zlog (NULL, LOG_ERR, "prefix_copy(): Unknown address family %d",
 116               src->family);
 117       assert (0);
 118     }
 119 }
 120
 121 /*
 122  * Return 1 if the address/netmask contained in the prefix structure
 123  * is the same, and else return 0.  For this routine, 'same' requires
 124  * that not only the prefix length and the network part be the same,
 125  * but also the host part.  Thus, 10.0.0.1/8 and 10.0.0.2/8 are not
 126  * the same.  Note that this routine has the same return value sense
 127  * as '==' (which is different from prefix_cmp).
 128  */
 129 int
 130 prefix_same (const struct prefix *p1, const struct prefix *p2)
 131 {
 132   if (p1->family == p2->family && p1->prefixlen == p2->prefixlen)
 133     {
 134       if (p1->family == AF_INET)
 135         if (IPV4_ADDR_SAME (&p1->u.prefix, &p2->u.prefix))
 136           return 1;
 137 #ifdef HAVE_IPV6
 138       if (p1->family == AF_INET6 )
 139         if (IPV6_ADDR_SAME (&p1->u.prefix, &p2->u.prefix))
 140           return 1;
 141 #endif /* HAVE_IPV6 */
 142     }
 143   return 0;
 144 }
 145
 146 /*
 147  * Return 0 if the network prefixes represented by the struct prefix
 148  * arguments are the same prefix, and 1 otherwise.  Network prefixes
 149  * are considered the same if the prefix lengths are equal and the
 150  * network parts are the same.  Host bits (which are considered masked
 151  * by the prefix length) are not significant.  Thus, 10.0.0.1/8 and
 152  * 10.0.0.2/8 are considered equivalent by this routine.  Note that
 153  * this routine has the same return sense as strcmp (which is different
 154  * from prefix_same).
 155  */
 156 int
 157 prefix_cmp (const struct prefix *p1, const struct prefix *p2)
 158 {
 159   int offset;
 160   int shift;
 161
 162   /* Set both prefix's head pointer. */
 163   const u_char *pp1 = (const u_char *)&p1->u.prefix;
 164   const u_char *pp2 = (const u_char *)&p2->u.prefix;
 165
 166   if (p1->family != p2->family || p1->prefixlen != p2->prefixlen)
 167     return 1;
 168
 169   offset = p1->prefixlen / 8;
 170   shift = p1->prefixlen % 8;
 171
 172   if (shift)
 173     if (maskbit[shift] & (pp1[offset] ^ pp2[offset]))
 174       return 1;
 175
 176   while (offset--)
 177     if (pp1[offset] != pp2[offset])
 178       return 1;
 179
 180   return 0;
 181 }
 182
 183 /* Return prefix family type string. */
 184 const char *
 185 prefix_family_str (const struct prefix *p)
 186 {
 187   if (p->family == AF_INET)
 188     return "inet";
 189 #ifdef HAVE_IPV6
 190   if (p->family == AF_INET6)
 191     return "inet6";
 192 #endif /* HAVE_IPV6 */
 193   return "unspec";
 194 }
 195
 196 /* Allocate new prefix_ipv4 structure. */
 197 struct prefix_ipv4 *
 198 prefix_ipv4_new ()
 199 {
 200   struct prefix_ipv4 *p;
 201
 202   /* Call prefix_new to allocate a full-size struct prefix to avoid problems
 203      where the struct prefix_ipv4 is cast to struct prefix and unallocated
 204      bytes were being referenced (e.g. in structure assignments). */
 205   p = (struct prefix_ipv4 *)prefix_new();
 206   p->family = AF_INET;
 207   return p;
 208 }
 209
 210 /* Free prefix_ipv4 structure. */
 211 void
 212 prefix_ipv4_free (struct prefix_ipv4 *p)
 213 {
 214   prefix_free((struct prefix *)p);
 215 }
 216
 217 /* When string format is invalid return 0. */
 218 int
 219 str2prefix_ipv4 (const char *str, struct prefix_ipv4 *p)
 220 {
 221   int ret;
 222   int plen;
 223   char *pnt;
 224   char *cp;
 225
 226   /* Find slash inside string. */
 227   pnt = strchr (str, '/');
 228
 229   /* String doesn't contail slash. */
 230   if (pnt == NULL)
 231     {
 232       /* Convert string to prefix. */
 233       ret = inet_aton (str, &p->prefix);
 234       if (ret == 0)
 235         return 0;
 236
 237       /* If address doesn't contain slash we assume it host address. */
 238       p->family = AF_INET;
 239       p->prefixlen = IPV4_MAX_BITLEN;
 240
 241       return ret;
 242     }
 243   else
 244     {
 245       cp = XMALLOC (MTYPE_TMP, (pnt - str) + 1);
 246       strncpy (cp, str, pnt - str);
 247       *(cp + (pnt - str)) = '\0';
 248       ret = inet_aton (cp, &p->prefix);
 249       XFREE (MTYPE_TMP, cp);
 250
 251       /* Get prefix length. */
 252       plen = (u_char) atoi (++pnt);
 253       if (plen > IPV4_MAX_PREFIXLEN)
 254         return 0;
 255
 256       p->family = AF_INET;
 257       p->prefixlen = plen;
 258     }
 259
 260   return ret;
 261 }
 262
 263 /* Convert masklen into IP address's netmask. */
 264 void
 265 masklen2ip (int masklen, struct in_addr *netmask)
 266 {
 267   u_char *pnt;
 268   int bit;
 269   int offset;
 270
 271   memset (netmask, 0, sizeof (struct in_addr));
 272   pnt = (unsigned char *) netmask;
 273
 274   offset = masklen / 8;
 275   bit = masklen % 8;
 276
 277   while (offset--)
 278     *pnt++ = 0xff;
 279
 280   if (bit)
 281     *pnt = maskbit[bit];
 282 }
 283
 284 /* Convert IP address's netmask into integer. We assume netmask is
 285    sequential one. Argument netmask should be network byte order. */
 286 u_char
 287 ip_masklen (struct in_addr netmask)
 288 {
 289   u_char len;
 290   u_char *pnt;
 291   u_char *end;
 292   u_char val;
 293
 294   len = 0;
 295   pnt = (u_char *) &netmask;
 296   end = pnt + 4;
 297
 298   while ((pnt < end) && (*pnt == 0xff))
 299     {
 300       len+= 8;
 301       pnt++;
 302     }
 303
 304   if (pnt < end)
 305     {
 306       val = *pnt;
 307       while (val)
 308         {
 309           len++;
 310           val <<= 1;
 311         }
 312     }
 313   return len;
 314 }
 315
 316 /* Apply mask to IPv4 prefix. */
 317 void
 318 apply_mask_ipv4 (struct prefix_ipv4 *p)
 319 {
 320   u_char *pnt;
 321   int index;
 322   int offset;
 323
 324   index = p->prefixlen / 8;
 325
 326   if (index < 4)
 327     {
 328       pnt = (u_char *) &p->prefix;
 329       offset = p->prefixlen % 8;
 330
 331       pnt[index] &= maskbit[offset];
 332       index++;
 333
 334       while (index < 4)
 335         pnt[index++] = 0;
 336     }
 337 }
 338
 339 /* If prefix is 0.0.0.0/0 then return 1 else return 0. */
 340 int
 341 prefix_ipv4_any (const struct prefix_ipv4 *p)
 342 {
 343   return (p->prefix.s_addr == 0 && p->prefixlen == 0);
 344 }
 345 \f
 346 #ifdef HAVE_IPV6
 347
 348 /* Allocate a new ip version 6 route */
 349 struct prefix_ipv6 *
 350 prefix_ipv6_new (void)
 351 {
 352   struct prefix_ipv6 *p;
 353
 354   /* Allocate a full-size struct prefix to avoid problems with structure
 355      size mismatches. */
 356   p = (struct prefix_ipv6 *)prefix_new();
 357   p->family = AF_INET6;
 358   return p;
 359 }
 360
 361 /* Free prefix for IPv6. */
 362 void
 363 prefix_ipv6_free (struct prefix_ipv6 *p)
 364 {
 365   prefix_free((struct prefix *)p);
 366 }
 367
 368 /* If given string is valid return pin6 else return NULL */
 369 int
 370 str2prefix_ipv6 (const char *str, struct prefix_ipv6 *p)
 371 {
 372   char *pnt;
 373   char *cp;
 374   int ret;
 375
 376   pnt = strchr (str, '/');
 377
 378   /* If string doesn't contain `/' treat it as host route. */
 379   if (pnt == NULL)
 380     {
 381       ret = inet_pton (AF_INET6, str, &p->prefix);
 382       if (ret != 1)
 383         return 0;
 384       p->prefixlen = IPV6_MAX_BITLEN;
 385     }
 386   else
 387     {
 388       int plen;
 389
 390       cp = XMALLOC (0, (pnt - str) + 1);
 391       strncpy (cp, str, pnt - str);
 392       *(cp + (pnt - str)) = '\0';
 393       ret = inet_pton (AF_INET6, cp, &p->prefix);
 394       free (cp);
 395       if (ret != 1)
 396         return 0;
 397       plen = (u_char) atoi (++pnt);
 398       if (plen > 128)
 399         return 0;
 400       p->prefixlen = plen;
 401     }
 402   p->family = AF_INET6;
 403
 404   return ret;
 405 }
 406
 407 /* Convert struct in6_addr netmask into integer.
 408  * FIXME return u_char as ip_maskleni() does. */
 409 int
 410 ip6_masklen (struct in6_addr netmask)
 411 {
 412   int len = 0;
 413   unsigned char val;
 414   unsigned char *pnt;
 415
 416   pnt = (unsigned char *) & netmask;
 417
 418   while ((*pnt == 0xff) && len < 128)
 419     {
 420       len += 8;
 421       pnt++;
 422     }
 423
 424   if (len < 128)
 425     {
 426       val = *pnt;
 427       while (val)
 428         {
 429           len++;
 430           val <<= 1;
 431         }
 432     }
 433   return len;
 434 }
 435
 436 void
 437 masklen2ip6 (int masklen, struct in6_addr *netmask)
 438 {
 439   unsigned char *pnt;
 440   int bit;
 441   int offset;
 442
 443   memset (netmask, 0, sizeof (struct in6_addr));
 444   pnt = (unsigned char *) netmask;
 445
 446   offset = masklen / 8;
 447   bit = masklen % 8;
 448
 449   while (offset--)
 450     *pnt++ = 0xff;
 451
 452   if (bit)
 453     *pnt = maskbit[bit];
 454 }
 455
 456 void
 457 apply_mask_ipv6 (struct prefix_ipv6 *p)
 458 {
 459   u_char *pnt;
 460   int index;
 461   int offset;
 462
 463   index = p->prefixlen / 8;
 464
 465   if (index < 16)
 466     {
 467       pnt = (u_char *) &p->prefix;
 468       offset = p->prefixlen % 8;
 469
 470       pnt[index] &= maskbit[offset];
 471       index++;
 472
 473       while (index < 16)
 474         pnt[index++] = 0;
 475     }
 476 }
 477
 478 void
 479 str2in6_addr (const char *str, struct in6_addr *addr)
 480 {
 481   int i;
 482   unsigned int x;
 483
 484   /* %x must point to unsinged int */
 485   for (i = 0; i < 16; i++)
 486     {
 487       sscanf (str + (i * 2), "%02x", &x);
 488       addr->s6_addr[i] = x & 0xff;
 489     }
 490 }
 491 #endif /* HAVE_IPV6 */
 492
 493 void
 494 apply_mask (struct prefix *p)
 495 {
 496   switch (p->family)
 497     {
 498       case AF_INET:
 499         apply_mask_ipv4 ((struct prefix_ipv4 *)p);
 500         break;
 501 #ifdef HAVE_IPV6
 502       case AF_INET6:
 503         apply_mask_ipv6 ((struct prefix_ipv6 *)p);
 504         break;
 505 #endif /* HAVE_IPV6 */
 506       default:
 507         break;
 508     }
 509   return;
 510 }
 511
 512 /* Utility function of convert between struct prefix <=> union sockunion.
 513  * FIXME This function isn't used anywhere. */
 514 struct prefix *
 515 sockunion2prefix (const union sockunion *dest,
 516                   const union sockunion *mask)
 517 {
 518   if (dest->sa.sa_family == AF_INET)
 519     {
 520       struct prefix_ipv4 *p;
 521
 522       p = prefix_ipv4_new ();
 523       p->family = AF_INET;
 524       p->prefix = dest->sin.sin_addr;
 525       p->prefixlen = ip_masklen (mask->sin.sin_addr);
 526       return (struct prefix *) p;
 527     }
 528 #ifdef HAVE_IPV6
 529   if (dest->sa.sa_family == AF_INET6)
 530     {
 531       struct prefix_ipv6 *p;
 532
 533       p = prefix_ipv6_new ();
 534       p->family = AF_INET6;
 535       p->prefixlen = ip6_masklen (mask->sin6.sin6_addr);
 536       memcpy (&p->prefix, &dest->sin6.sin6_addr, sizeof (struct in6_addr));
 537       return (struct prefix *) p;
 538     }
 539 #endif /* HAVE_IPV6 */
 540   return NULL;
 541 }
 542
 543 /* Utility function of convert between struct prefix <=> union sockunion. */
 544 struct prefix *
 545 sockunion2hostprefix (const union sockunion *su)
 546 {
 547   if (su->sa.sa_family == AF_INET)
 548     {
 549       struct prefix_ipv4 *p;
 550
 551       p = prefix_ipv4_new ();
 552       p->family = AF_INET;
 553       p->prefix = su->sin.sin_addr;
 554       p->prefixlen = IPV4_MAX_BITLEN;
 555       return (struct prefix *) p;
 556     }
 557 #ifdef HAVE_IPV6
 558   if (su->sa.sa_family == AF_INET6)
 559     {
 560       struct prefix_ipv6 *p;
 561
 562       p = prefix_ipv6_new ();
 563       p->family = AF_INET6;
 564       p->prefixlen = IPV6_MAX_BITLEN;
 565       memcpy (&p->prefix, &su->sin6.sin6_addr, sizeof (struct in6_addr));
 566       return (struct prefix *) p;
 567     }
 568 #endif /* HAVE_IPV6 */
 569   return NULL;
 570 }
 571
 572 int
 573 prefix_blen (const struct prefix *p)
 574 {
 575   switch (p->family)
 576     {
 577     case AF_INET:
 578       return IPV4_MAX_BYTELEN;
 579       break;
 580 #ifdef HAVE_IPV6
 581     case AF_INET6:
 582       return IPV6_MAX_BYTELEN;
 583       break;
 584 #endif /* HAVE_IPV6 */
 585     }
 586   return 0;
 587 }
 588
 589 /* Generic function for conversion string to struct prefix. */
 590 int
 591 str2prefix (const char *str, struct prefix *p)
 592 {
 593   int ret;
 594
 595   /* First we try to convert string to struct prefix_ipv4. */
 596   ret = str2prefix_ipv4 (str, (struct prefix_ipv4 *) p);
 597   if (ret)
 598     return ret;
 599
 600 #ifdef HAVE_IPV6
 601   /* Next we try to convert string to struct prefix_ipv6. */
 602   ret = str2prefix_ipv6 (str, (struct prefix_ipv6 *) p);
 603   if (ret)
 604     return ret;
 605 #endif /* HAVE_IPV6 */
 606
 607   return 0;
 608 }
 609
 610 int
 611 prefix2str (const struct prefix *p, char *str, int size)
 612 {
 613   char buf[BUFSIZ];
 614
 615   inet_ntop (p->family, &p->u.prefix, buf, BUFSIZ);
 616   snprintf (str, size, "%s/%d", buf, p->prefixlen);
 617   return 0;
 618 }
 619
 620 struct prefix *
 621 prefix_new ()
 622 {
 623   struct prefix *p;
 624
 625   p = XCALLOC (MTYPE_PREFIX, sizeof *p);
 626   return p;
 627 }
 628
 629 /* Free prefix structure. */
 630 void
 631 prefix_free (struct prefix *p)
 632 {
 633   XFREE (MTYPE_PREFIX, p);
 634 }
 635
 636 /* Utility function.  Check the string only contains digit
 637  * character.
 638  * FIXME str.[c|h] would be better place for this function. */
 639 int
 640 all_digit (const char *str)
 641 {
 642   for (; *str != '\0'; str++)
 643     if (!isdigit ((int) *str))
 644       return 0;
 645   return 1;
 646 }
 647
 648 /* Utility function to convert ipv4 prefixes to Classful prefixes */
 649 void apply_classful_mask_ipv4 (struct prefix_ipv4 *p)
 650 {
 651
 652   u_int32_t destination;
 653
 654   destination = ntohl (p->prefix.s_addr);
 655
 656   if (p->prefixlen == IPV4_MAX_PREFIXLEN);
 657   /* do nothing for host routes */
 658   else if (IN_CLASSC (destination))
 659     {
 660       p->prefixlen=24;
 661       apply_mask_ipv4(p);
 662     }
 663   else if (IN_CLASSB(destination))
 664     {
 665       p->prefixlen=16;
 666       apply_mask_ipv4(p);
 667     }
 668   else
 669     {
 670       p->prefixlen=8;
 671       apply_mask_ipv4(p);
 672     }
 673 }
 674
 675 in_addr_t
 676 ipv4_network_addr (in_addr_t hostaddr, int masklen)
 677 {
 678   struct in_addr mask;
 679
 680   masklen2ip (masklen, &mask);
 681   return hostaddr & mask.s_addr;
 682 }
 683
 684 in_addr_t
 685 ipv4_broadcast_addr (in_addr_t hostaddr, int masklen)
 686 {
 687   struct in_addr mask;
 688
 689   masklen2ip (masklen, &mask);
 690   return (masklen != IPV4_MAX_PREFIXLEN-1) ?
 691          /* normal case */
 692          (hostaddr | ~mask.s_addr) :
 693          /* special case for /31 */
 694          (hostaddr ^ ~mask.s_addr);
 695 }
 696
 697 /* Utility function to convert ipv4 netmask to prefixes
 698    ex.) "1.1.0.0" "255.255.0.0" => "1.1.0.0/16"
 699    ex.) "1.0.0.0" NULL => "1.0.0.0/8"                   */
 700 int
 701 netmask_str2prefix_str (const char *net_str, const char *mask_str,
 702                         char *prefix_str)
 703 {
 704   struct in_addr network;
 705   struct in_addr mask;
 706   u_char prefixlen;
 707   u_int32_t destination;
 708   int ret;
 709
 710   ret = inet_aton (net_str, &network);
 711   if (! ret)
 712     return 0;
 713
 714   if (mask_str)
 715     {
 716       ret = inet_aton (mask_str, &mask);
 717       if (! ret)
 718         return 0;
 719
 720       prefixlen = ip_masklen (mask);
 721     }
 722   else
 723     {
 724       destination = ntohl (network.s_addr);
 725
 726       if (network.s_addr == 0)
 727         prefixlen = 0;
 728       else if (IN_CLASSC (destination))
 729         prefixlen = 24;
 730       else if (IN_CLASSB (destination))
 731         prefixlen = 16;
 732       else if (IN_CLASSA (destination))
 733         prefixlen = 8;
 734       else
 735         return 0;
 736     }
 737
 738   sprintf (prefix_str, "%s/%d", net_str, prefixlen);
 739
 740   return 1;
 741 }
 742
 743 #ifdef HAVE_IPV6
 744 /* Utility function for making IPv6 address string. */
 745 const char *
 746 inet6_ntoa (struct in6_addr addr)
 747 {
 748   static char buf[INET6_ADDRSTRLEN];
 749
 750   inet_ntop (AF_INET6, &addr, buf, INET6_ADDRSTRLEN);
 751   return buf;
 752 }
 753 #endif /* HAVE_IPV6 */