external/bsd/libbind/dist/inet/inet_cidr_ntop.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (c) 1998,1999 by Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #if defined(LIBC_SCCS) && !defined(lint)
  21 static const char rcsid[] = "Id: inet_cidr_ntop.c,v 1.7 2006/10/11 02:18:18 marka Exp";
  22 #endif
  23
  24 #include "port_before.h"
  25
  26 #include <sys/types.h>
  27 #include <sys/socket.h>
  28 #include <netinet/in.h>
  29 #include <arpa/nameser.h>
  30 #include <arpa/inet.h>
  31
  32 #include <errno.h>
  33 #include <stdio.h>
  34 #include <string.h>
  35 #include <stdlib.h>
  36
  37 #include "port_after.h"
  38
  39 #ifdef SPRINTF_CHAR
  40 # define SPRINTF(x) strlen(sprintf/**/x)
  41 #else
  42 # define SPRINTF(x) ((size_t)sprintf x)
  43 #endif
  44
  45 static char *
  46 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size);
  47 static char *
  48 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size);
  49
  50 /*%
  51  * char *
  52  * inet_cidr_ntop(af, src, bits, dst, size)
  53  *      convert network address from network to presentation format.
  54  *      "src"'s size is determined from its "af".
  55  * return:
  56  *      pointer to dst, or NULL if an error occurred (check errno).
  57  * note:
  58  *      192.5.5.1/28 has a nonzero host part, which means it isn't a network
  59  *      as called for by inet_net_ntop() but it can be a host address with
  60  *      an included netmask.
  61  * author:
  62  *      Paul Vixie (ISC), October 1998
  63  */
  64 char *
  65 inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size) {
  66         switch (af) {
  67         case AF_INET:
  68                 return (inet_cidr_ntop_ipv4(src, bits, dst, size));
  69         case AF_INET6:
  70                 return (inet_cidr_ntop_ipv6(src, bits, dst, size));
  71         default:
  72                 errno = EAFNOSUPPORT;
  73                 return (NULL);
  74         }
  75 }
  76
  77 static int
  78 decoct(const u_char *src, int bytes, char *dst, size_t size) {
  79         char *odst = dst;
  80         char *t;
  81         int b;
  82
  83         for (b = 1; b <= bytes; b++) {
  84                 if (size < sizeof "255.")
  85                         return (0);
  86                 t = dst;
  87                 dst += SPRINTF((dst, "%u", *src++));
  88                 if (b != bytes) {
  89                         *dst++ = '.';
  90                         *dst = '\0';
  91                 }
  92                 size -= (size_t)(dst - t);
  93         }
  94         return (dst - odst);
  95 }
  96
  97 /*%
  98  * static char *
  99  * inet_cidr_ntop_ipv4(src, bits, dst, size)
 100  *      convert IPv4 network address from network to presentation format.
 101  *      "src"'s size is determined from its "af".
 102  * return:
 103  *      pointer to dst, or NULL if an error occurred (check errno).
 104  * note:
 105  *      network byte order assumed.  this means 192.5.5.240/28 has
 106  *      0b11110000 in its fourth octet.
 107  * author:
 108  *      Paul Vixie (ISC), October 1998
 109  */
 110 static char *
 111 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) {
 112         char *odst = dst;
 113         size_t len = 4;
 114         size_t b;
 115         size_t bytes;
 116
 117         if ((bits < -1) || (bits > 32)) {
 118                 errno = EINVAL;
 119                 return (NULL);
 120         }
 121
 122         /* Find number of significant bytes in address. */
 123         if (bits == -1)
 124                 len = 4;
 125         else
 126                 for (len = 1, b = 1 ; b < 4U; b++)
 127                         if (*(src + b))
 128                                 len = b + 1;
 129
 130         /* Format whole octets plus nonzero trailing octets. */
 131         bytes = (((bits <= 0) ? 1 : bits) + 7) / 8;
 132         if (len > bytes)
 133                 bytes = len;
 134         b = decoct(src, bytes, dst, size);
 135         if (b == 0U)
 136                 goto emsgsize;
 137         dst += b;
 138         size -= b;
 139
 140         if (bits != -1) {
 141                 /* Format CIDR /width. */
 142                 if (size < sizeof "/32")
 143                         goto emsgsize;
 144                 dst += SPRINTF((dst, "/%u", bits));
 145         }
 146
 147         return (odst);
 148
 149  emsgsize:
 150         errno = EMSGSIZE;
 151         return (NULL);
 152 }
 153
 154 static char *
 155 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
 156         /*
 157          * Note that int32_t and int16_t need only be "at least" large enough
 158          * to contain a value of the specified size.  On some systems, like
 159          * Crays, there is no such thing as an integer variable with 16 bits.
 160          * Keep this in mind if you think this function should have been coded
 161          * to use pointer overlays.  All the world's not a VAX.
 162          */
 163         char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255/128"];
 164         char *tp;
 165         struct { int base, len; } best, cur;
 166         u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
 167         int i;
 168
 169         if ((bits < -1) || (bits > 128)) {
 170                 errno = EINVAL;
 171                 return (NULL);
 172         }
 173
 174         /*
 175          * Preprocess:
 176          *      Copy the input (bytewise) array into a wordwise array.
 177          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 178          */
 179         memset(words, '\0', sizeof words);
 180         for (i = 0; i < NS_IN6ADDRSZ; i++)
 181                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 182         best.base = -1;
 183         best.len = 0;
 184         cur.base = -1;
 185         cur.len = 0;
 186         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 187                 if (words[i] == 0) {
 188                         if (cur.base == -1)
 189                                 cur.base = i, cur.len = 1;
 190                         else
 191                                 cur.len++;
 192                 } else {
 193                         if (cur.base != -1) {
 194                                 if (best.base == -1 || cur.len > best.len)
 195                                         best = cur;
 196                                 cur.base = -1;
 197                         }
 198                 }
 199         }
 200         if (cur.base != -1) {
 201                 if (best.base == -1 || cur.len > best.len)
 202                         best = cur;
 203         }
 204         if (best.base != -1 && best.len < 2)
 205                 best.base = -1;
 206
 207         /*
 208          * Format the result.
 209          */
 210         tp = tmp;
 211         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 212                 /* Are we inside the best run of 0x00's? */
 213                 if (best.base != -1 && i >= best.base &&
 214                     i < (best.base + best.len)) {
 215                         if (i == best.base)
 216                                 *tp++ = ':';
 217                         continue;
 218                 }
 219                 /* Are we following an initial run of 0x00s or any real hex? */
 220                 if (i != 0)
 221                         *tp++ = ':';
 222                 /* Is this address an encapsulated IPv4? */
 223                 if (i == 6 && best.base == 0 && (best.len == 6 ||
 224                     (best.len == 7 && words[7] != 0x0001) ||
 225                     (best.len == 5 && words[5] == 0xffff))) {
 226                         int n;
 227
 228                         if (src[15] || bits == -1 || bits > 120)
 229                                 n = 4;
 230                         else if (src[14] || bits > 112)
 231                                 n = 3;
 232                         else
 233                                 n = 2;
 234                         n = decoct(src+12, n, tp, sizeof tmp - (tp - tmp));
 235                         if (n == 0) {
 236                                 errno = EMSGSIZE;
 237                                 return (NULL);
 238                         }
 239                         tp += strlen(tp);
 240                         break;
 241                 }
 242                 tp += SPRINTF((tp, "%x", words[i]));
 243         }
 244
 245         /* Was it a trailing run of 0x00's? */
 246         if (best.base != -1 && (best.base + best.len) ==
 247             (NS_IN6ADDRSZ / NS_INT16SZ))
 248                 *tp++ = ':';
 249         *tp = '\0';
 250
 251         if (bits != -1)
 252                 tp += SPRINTF((tp, "/%u", bits));
 253
 254         /*
 255          * Check for overflow, copy, and we're done.
 256          */
 257         if ((size_t)(tp - tmp) > size) {
 258                 errno = EMSGSIZE;
 259                 return (NULL);
 260         }
 261         strcpy(dst, tmp);
 262         return (dst);
 263 }
 264
 265 /*! \file */