contrib/bind-9.2.4rc7/lib/bind/inet/inet_cidr_ntop.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1998,1999 by Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #if defined(LIBC_SCCS) && !defined(lint)
  19 static const char rcsid[] = "$Id: inet_cidr_ntop.c,v 1.1.2.3 2004/03/17 00:40:10 marka Exp $";
  20 #endif
  21
  22 #include "port_before.h"
  23
  24 #include <sys/types.h>
  25 #include <sys/socket.h>
  26 #include <netinet/in.h>
  27 #include <arpa/nameser.h>
  28 #include <arpa/inet.h>
  29
  30 #include <errno.h>
  31 #include <stdio.h>
  32 #include <string.h>
  33 #include <stdlib.h>
  34
  35 #include "port_after.h"
  36
  37 #ifdef SPRINTF_CHAR
  38 # define SPRINTF(x) strlen(sprintf/**/x)
  39 #else
  40 # define SPRINTF(x) ((size_t)sprintf x)
  41 #endif
  42
  43 static char *   inet_cidr_ntop_ipv4 __P((const u_char *src, int bits,
  44                                          char *dst, size_t size));
  45 static char *   inet_cidr_ntop_ipv6 __P((const u_char *src, int bits,
  46                                          char *dst, size_t size));
  47
  48 /*
  49  * char *
  50  * inet_cidr_ntop(af, src, bits, dst, size)
  51  *      convert network address from network to presentation format.
  52  *      "src"'s size is determined from its "af".
  53  * return:
  54  *      pointer to dst, or NULL if an error occurred (check errno).
  55  * note:
  56  *      192.5.5.1/28 has a nonzero host part, which means it isn't a network
  57  *      as called for by inet_net_ntop() but it can be a host address with
  58  *      an included netmask.
  59  * author:
  60  *      Paul Vixie (ISC), October 1998
  61  */
  62 char *
  63 inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size) {
  64         switch (af) {
  65         case AF_INET:
  66                 return (inet_cidr_ntop_ipv4(src, bits, dst, size));
  67         case AF_INET6:
  68                 return (inet_cidr_ntop_ipv6(src, bits, dst, size));
  69         default:
  70                 errno = EAFNOSUPPORT;
  71                 return (NULL);
  72         }
  73 }
  74
  75 static int
  76 decoct(const u_char *src, int bytes, char *dst, size_t size) {
  77         char *odst = dst;
  78         char *t;
  79         int b;
  80
  81         for (b = 1; b <= bytes; b++) {
  82                 if (size < sizeof "255.")
  83                         return (0);
  84                 t = dst;
  85                 dst += SPRINTF((dst, "%u", *src++));
  86                 if (b != bytes) {
  87                         *dst++ = '.';
  88                         *dst = '\0';
  89                 }
  90                 size -= (size_t)(dst - t);
  91         }
  92         return (dst - odst);
  93 }
  94
  95 /*
  96  * static char *
  97  * inet_cidr_ntop_ipv4(src, bits, dst, size)
  98  *      convert IPv4 network address from network to presentation format.
  99  *      "src"'s size is determined from its "af".
 100  * return:
 101  *      pointer to dst, or NULL if an error occurred (check errno).
 102  * note:
 103  *      network byte order assumed.  this means 192.5.5.240/28 has
 104  *      0b11110000 in its fourth octet.
 105  * author:
 106  *      Paul Vixie (ISC), October 1998
 107  */
 108 static char *
 109 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) {
 110         char *odst = dst;
 111         size_t len = 4;
 112         size_t b;
 113         size_t bytes;
 114
 115         if ((bits < -1) || (bits > 32)) {
 116                 errno = EINVAL;
 117                 return (NULL);
 118         }
 119
 120         /* Find number of significant bytes in address. */
 121         if (bits == -1)
 122                 len = 4;
 123         else
 124                 for (len = 1, b = 1 ; b < 4U; b++)
 125                         if (*(src + b))
 126                                 len = b + 1;
 127
 128         /* Format whole octets plus nonzero trailing octets. */
 129         bytes = (((bits <= 0) ? 1 : bits) + 7) / 8;
 130         if (len > bytes)
 131                 bytes = len;
 132         b = decoct(src, bytes, dst, size);
 133         if (b == 0U)
 134                 goto emsgsize;
 135         dst += b;
 136         size -= b;
 137
 138         if (bits != -1) {
 139                 /* Format CIDR /width. */
 140                 if (size < sizeof "/32")
 141                         goto emsgsize;
 142                 dst += SPRINTF((dst, "/%u", bits));
 143         }
 144
 145         return (odst);
 146
 147  emsgsize:
 148         errno = EMSGSIZE;
 149         return (NULL);
 150 }
 151
 152 static char *
 153 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
 154         /*
 155          * Note that int32_t and int16_t need only be "at least" large enough
 156          * to contain a value of the specified size.  On some systems, like
 157          * Crays, there is no such thing as an integer variable with 16 bits.
 158          * Keep this in mind if you think this function should have been coded
 159          * to use pointer overlays.  All the world's not a VAX.
 160          */
 161         char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255/128"];
 162         char *tp;
 163         struct { int base, len; } best, cur;
 164         u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
 165         int i;
 166
 167         if ((bits < -1) || (bits > 128)) {
 168                 errno = EINVAL;
 169                 return (NULL);
 170         }
 171
 172         /*
 173          * Preprocess:
 174          *      Copy the input (bytewise) array into a wordwise array.
 175          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 176          */
 177         memset(words, '\0', sizeof words);
 178         for (i = 0; i < NS_IN6ADDRSZ; i++)
 179                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 180         best.base = -1;
 181         cur.base = -1;
 182         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 183                 if (words[i] == 0) {
 184                         if (cur.base == -1)
 185                                 cur.base = i, cur.len = 1;
 186                         else
 187                                 cur.len++;
 188                 } else {
 189                         if (cur.base != -1) {
 190                                 if (best.base == -1 || cur.len > best.len)
 191                                         best = cur;
 192                                 cur.base = -1;
 193                         }
 194                 }
 195         }
 196         if (cur.base != -1) {
 197                 if (best.base == -1 || cur.len > best.len)
 198                         best = cur;
 199         }
 200         if (best.base != -1 && best.len < 2)
 201                 best.base = -1;
 202
 203         /*
 204          * Format the result.
 205          */
 206         tp = tmp;
 207         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 208                 /* Are we inside the best run of 0x00's? */
 209                 if (best.base != -1 && i >= best.base &&
 210                     i < (best.base + best.len)) {
 211                         if (i == best.base)
 212                                 *tp++ = ':';
 213                         continue;
 214                 }
 215                 /* Are we following an initial run of 0x00s or any real hex? */
 216                 if (i != 0)
 217                         *tp++ = ':';
 218                 /* Is this address an encapsulated IPv4? */
 219                 if (i == 6 && best.base == 0 && (best.len == 6 ||
 220                     (best.len == 7 && words[7] != 0x0001) ||
 221                     (best.len == 5 && words[5] == 0xffff))) {
 222                         int n;
 223
 224                         if (src[15] || bits == -1 || bits > 120)
 225                                 n = 4;
 226                         else if (src[14] || bits > 112)
 227                                 n = 3;
 228                         else
 229                                 n = 2;
 230                         n = decoct(src+12, n, tp, sizeof tmp - (tp - tmp));
 231                         if (n == 0) {
 232                                 errno = EMSGSIZE;
 233                                 return (NULL);
 234                         }
 235                         tp += strlen(tp);
 236                         break;
 237                 }
 238                 tp += SPRINTF((tp, "%x", words[i]));
 239         }
 240
 241         /* Was it a trailing run of 0x00's? */
 242         if (best.base != -1 && (best.base + best.len) ==
 243             (NS_IN6ADDRSZ / NS_INT16SZ))
 244                 *tp++ = ':';
 245         *tp = '\0';
 246
 247         if (bits != -1)
 248                 tp += SPRINTF((tp, "/%u", bits));
 249
 250         /*
 251          * Check for overflow, copy, and we're done.
 252          */
 253         if ((size_t)(tp - tmp) > size) {
 254                 errno = EMSGSIZE;
 255                 return (NULL);
 256         }
 257         strcpy(dst, tmp);
 258         return (dst);
 259 }