contrib/bind-9.5.2/lib/bind/inet/inet_net_ntop.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1996,1999 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_net_ntop.c,v 1.5 2006/06/20 02:50:14 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/inet.h>
  28
  29 #include <errno.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <stdlib.h>
  33
  34 #include "port_after.h"
  35
  36 #ifdef SPRINTF_CHAR
  37 # define SPRINTF(x) strlen(sprintf/**/x)
  38 #else
  39 # define SPRINTF(x) ((size_t)sprintf x)
  40 #endif
  41
  42 static char *   inet_net_ntop_ipv4 __P((const u_char *src, int bits,
  43                                         char *dst, size_t size));
  44 static char *   inet_net_ntop_ipv6 __P((const u_char *src, int bits,
  45                                         char *dst, size_t size));
  46
  47 /*%
  48  * char *
  49  * inet_net_ntop(af, src, bits, dst, size)
  50  *      convert network number from network to presentation format.
  51  *      generates CIDR style result always.
  52  * return:
  53  *      pointer to dst, or NULL if an error occurred (check errno).
  54  * author:
  55  *      Paul Vixie (ISC), July 1996
  56  */
  57 char *
  58 inet_net_ntop(af, src, bits, dst, size)
  59         int af;
  60         const void *src;
  61         int bits;
  62         char *dst;
  63         size_t size;
  64 {
  65         switch (af) {
  66         case AF_INET:
  67                 return (inet_net_ntop_ipv4(src, bits, dst, size));
  68         case AF_INET6:
  69                 return (inet_net_ntop_ipv6(src, bits, dst, size));
  70         default:
  71                 errno = EAFNOSUPPORT;
  72                 return (NULL);
  73         }
  74 }
  75
  76 /*%
  77  * static char *
  78  * inet_net_ntop_ipv4(src, bits, dst, size)
  79  *      convert IPv4 network number from network to presentation format.
  80  *      generates CIDR style result always.
  81  * return:
  82  *      pointer to dst, or NULL if an error occurred (check errno).
  83  * note:
  84  *      network byte order assumed.  this means 192.5.5.240/28 has
  85  *      0b11110000 in its fourth octet.
  86  * author:
  87  *      Paul Vixie (ISC), July 1996
  88  */
  89 static char *
  90 inet_net_ntop_ipv4(src, bits, dst, size)
  91         const u_char *src;
  92         int bits;
  93         char *dst;
  94         size_t size;
  95 {
  96         char *odst = dst;
  97         char *t;
  98         u_int m;
  99         int b;
 100
 101         if (bits < 0 || bits > 32) {
 102                 errno = EINVAL;
 103                 return (NULL);
 104         }
 105
 106         if (bits == 0) {
 107                 if (size < sizeof "0")
 108                         goto emsgsize;
 109                 *dst++ = '0';
 110                 size--;
 111                 *dst = '\0';
 112         }
 113
 114         /* Format whole octets. */
 115         for (b = bits / 8; b > 0; b--) {
 116                 if (size <= sizeof "255.")
 117                         goto emsgsize;
 118                 t = dst;
 119                 dst += SPRINTF((dst, "%u", *src++));
 120                 if (b > 1) {
 121                         *dst++ = '.';
 122                         *dst = '\0';
 123                 }
 124                 size -= (size_t)(dst - t);
 125         }
 126
 127         /* Format partial octet. */
 128         b = bits % 8;
 129         if (b > 0) {
 130                 if (size <= sizeof ".255")
 131                         goto emsgsize;
 132                 t = dst;
 133                 if (dst != odst)
 134                         *dst++ = '.';
 135                 m = ((1 << b) - 1) << (8 - b);
 136                 dst += SPRINTF((dst, "%u", *src & m));
 137                 size -= (size_t)(dst - t);
 138         }
 139
 140         /* Format CIDR /width. */
 141         if (size <= sizeof "/32")
 142                 goto emsgsize;
 143         dst += SPRINTF((dst, "/%u", bits));
 144         return (odst);
 145
 146  emsgsize:
 147         errno = EMSGSIZE;
 148         return (NULL);
 149 }
 150
 151 /*%
 152  * static char *
 153  * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
 154  *      convert IPv6 network number from network to presentation format.
 155  *      generates CIDR style result always. Picks the shortest representation
 156  *      unless the IP is really IPv4.
 157  *      always prints specified number of bits (bits).
 158  * return:
 159  *      pointer to dst, or NULL if an error occurred (check errno).
 160  * note:
 161  *      network byte order assumed.  this means 192.5.5.240/28 has
 162  *      0x11110000 in its fourth octet.
 163  * author:
 164  *      Vadim Kogan (UCB), June 2001
 165  *  Original version (IPv4) by Paul Vixie (ISC), July 1996
 166  */
 167
 168 static char *
 169 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
 170         u_int   m;
 171         int     b;
 172         int     p;
 173         int     zero_s, zero_l, tmp_zero_s, tmp_zero_l;
 174         int     i;
 175         int     is_ipv4 = 0;
 176         unsigned char inbuf[16];
 177         char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
 178         char    *cp;
 179         int     words;
 180         u_char  *s;
 181
 182         if (bits < 0 || bits > 128) {
 183                 errno = EINVAL;
 184                 return (NULL);
 185         }
 186
 187         cp = outbuf;
 188
 189         if (bits == 0) {
 190                 *cp++ = ':';
 191                 *cp++ = ':';
 192                 *cp = '\0';
 193         } else {
 194                 /* Copy src to private buffer.  Zero host part. */
 195                 p = (bits + 7) / 8;
 196                 memcpy(inbuf, src, p);
 197                 memset(inbuf + p, 0, 16 - p);
 198                 b = bits % 8;
 199                 if (b != 0) {
 200                         m = ~0 << (8 - b);
 201                         inbuf[p-1] &= m;
 202                 }
 203
 204                 s = inbuf;
 205
 206                 /* how many words need to be displayed in output */
 207                 words = (bits + 15) / 16;
 208                 if (words == 1)
 209                         words = 2;
 210
 211                 /* Find the longest substring of zero's */
 212                 zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
 213                 for (i = 0; i < (words * 2); i += 2) {
 214                         if ((s[i] | s[i+1]) == 0) {
 215                                 if (tmp_zero_l == 0)
 216                                         tmp_zero_s = i / 2;
 217                                 tmp_zero_l++;
 218                         } else {
 219                                 if (tmp_zero_l && zero_l < tmp_zero_l) {
 220                                         zero_s = tmp_zero_s;
 221                                         zero_l = tmp_zero_l;
 222                                         tmp_zero_l = 0;
 223                                 }
 224                         }
 225                 }
 226
 227                 if (tmp_zero_l && zero_l < tmp_zero_l) {
 228                         zero_s = tmp_zero_s;
 229                         zero_l = tmp_zero_l;
 230                 }
 231
 232                 if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
 233                     ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
 234                     ((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
 235                         is_ipv4 = 1;
 236
 237                 /* Format whole words. */
 238                 for (p = 0; p < words; p++) {
 239                         if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) {
 240                                 /* Time to skip some zeros */
 241                                 if (p == zero_s)
 242                                         *cp++ = ':';
 243                                 if (p == words - 1)
 244                                         *cp++ = ':';
 245                                 s++;
 246                                 s++;
 247                                 continue;
 248                         }
 249
 250                         if (is_ipv4 && p > 5 ) {
 251                                 *cp++ = (p == 6) ? ':' : '.';
 252                                 cp += SPRINTF((cp, "%u", *s++));
 253                                 /* we can potentially drop the last octet */
 254                                 if (p != 7 || bits > 120) {
 255                                         *cp++ = '.';
 256                                         cp += SPRINTF((cp, "%u", *s++));
 257                                 }
 258                         } else {
 259                                 if (cp != outbuf)
 260                                         *cp++ = ':';
 261                                 cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
 262                                 s += 2;
 263                         }
 264                 }
 265         }
 266         /* Format CIDR /width. */
 267         sprintf(cp, "/%u", bits);
 268         if (strlen(outbuf) + 1 > size)
 269                 goto emsgsize;
 270         strcpy(dst, outbuf);
 271
 272         return (dst);
 273
 274 emsgsize:
 275         errno = EMSGSIZE;
 276         return (NULL);
 277 }
 278
 279 /*! \file */