lib/libc/inet/inet_net_ntop.c

   1 /*
   2  * Copyright (c) 1996,1999 by Internet Software Consortium.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  */
  17
  18 #include <sys/cdefs.h>
  19 #if defined(LIBC_SCCS) && !defined(lint)
  20 #ifdef notdef
  21 static const char rcsid[] = "Id: inet_net_ntop.c,v 1.1.2.1 2002/08/02 02:17:21 marka Exp ";
  22 #else
  23 __RCSID("$NetBSD: inet_net_ntop.c,v 1.2 2009/02/07 07:25:22 lukem Exp $");
  24 #endif
  25 #endif
  26
  27 #include "port_before.h"
  28
  29 #include "namespace.h"
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include <netinet/in.h>
  33 #include <arpa/inet.h>
  34
  35 #include <errno.h>
  36 #include <stdio.h>
  37 #include <string.h>
  38 #include <stdlib.h>
  39
  40 #include "port_after.h"
  41
  42 #ifdef __weak_alias
  43 __weak_alias(inet_net_ntop,_inet_net_ntop)
  44 #endif
  45
  46 #ifdef SPRINTF_CHAR
  47 # define SPRINTF(x) strlen(sprintf/**/x)
  48 #else
  49 # define SPRINTF(x) sprintf x
  50 #endif
  51
  52 static char *   inet_net_ntop_ipv4 __P((const u_char *src, int bits,
  53                                         char *dst, size_t size));
  54 static char *   inet_net_ntop_ipv6 __P((const u_char *src, int bits,
  55                                         char *dst, size_t size));
  56
  57 /*
  58  * char *
  59  * inet_net_ntop(af, src, bits, dst, size)
  60  *      convert network number from network to presentation format.
  61  *      generates CIDR style result always.
  62  * return:
  63  *      pointer to dst, or NULL if an error occurred (check errno).
  64  * author:
  65  *      Paul Vixie (ISC), July 1996
  66  */
  67 char *
  68 inet_net_ntop(af, src, bits, dst, size)
  69         int af;
  70         const void *src;
  71         int bits;
  72         char *dst;
  73         size_t size;
  74 {
  75         switch (af) {
  76         case AF_INET:
  77                 return (inet_net_ntop_ipv4(src, bits, dst, size));
  78         case AF_INET6:
  79                 return (inet_net_ntop_ipv6(src, bits, dst, size));
  80         default:
  81                 errno = EAFNOSUPPORT;
  82                 return (NULL);
  83         }
  84 }
  85
  86 /*
  87  * static char *
  88  * inet_net_ntop_ipv4(src, bits, dst, size)
  89  *      convert IPv4 network number from network to presentation format.
  90  *      generates CIDR style result always.
  91  * return:
  92  *      pointer to dst, or NULL if an error occurred (check errno).
  93  * note:
  94  *      network byte order assumed.  this means 192.5.5.240/28 has
  95  *      0b11110000 in its fourth octet.
  96  * author:
  97  *      Paul Vixie (ISC), July 1996
  98  */
  99 static char *
 100 inet_net_ntop_ipv4(src, bits, dst, size)
 101         const u_char *src;
 102         int bits;
 103         char *dst;
 104         size_t size;
 105 {
 106         char *odst = dst;
 107         char *t;
 108         u_int m;
 109         int b;
 110
 111         if (bits < 0 || bits > 32) {
 112                 errno = EINVAL;
 113                 return (NULL);
 114         }
 115
 116         if (bits == 0) {
 117                 if (size < sizeof "0")
 118                         goto emsgsize;
 119                 *dst++ = '0';
 120                 size--;
 121                 *dst = '\0';
 122         }
 123
 124         /* Format whole octets. */
 125         for (b = bits / 8; b > 0; b--) {
 126                 if (size <= sizeof "255.")
 127                         goto emsgsize;
 128                 t = dst;
 129                 dst += SPRINTF((dst, "%u", *src++));
 130                 if (b > 1) {
 131                         *dst++ = '.';
 132                         *dst = '\0';
 133                 }
 134                 size -= (size_t)(dst - t);
 135         }
 136
 137         /* Format partial octet. */
 138         b = bits % 8;
 139         if (b > 0) {
 140                 if (size <= sizeof ".255")
 141                         goto emsgsize;
 142                 t = dst;
 143                 if (dst != odst)
 144                         *dst++ = '.';
 145                 m = ((1 << b) - 1) << (8 - b);
 146                 dst += SPRINTF((dst, "%u", *src & m));
 147                 size -= (size_t)(dst - t);
 148         }
 149
 150         /* Format CIDR /width. */
 151         if (size <= sizeof "/32")
 152                 goto emsgsize;
 153         dst += SPRINTF((dst, "/%u", bits));
 154         return (odst);
 155
 156  emsgsize:
 157         errno = EMSGSIZE;
 158         return (NULL);
 159 }
 160
 161 /*
 162  * static char *
 163  * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
 164  *      convert IPv6 network number from network to presentation format.
 165  *      generates CIDR style result always. Picks the shortest representation
 166  *      unless the IP is really IPv4.
 167  *      always prints specified number of bits (bits).
 168  * return:
 169  *      pointer to dst, or NULL if an error occurred (check errno).
 170  * note:
 171  *      network byte order assumed.  this means 192.5.5.240/28 has
 172  *      0x11110000 in its fourth octet.
 173  * author:
 174  *      Vadim Kogan (UCB), June 2001
 175  *  Original version (IPv4) by Paul Vixie (ISC), July 1996
 176  */
 177
 178 static char *
 179 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
 180         u_int   m;
 181         int     b;
 182         size_t  p;
 183         size_t  zero_s, zero_l, tmp_zero_s, tmp_zero_l;
 184         size_t  i;
 185         int     is_ipv4 = 0;
 186         unsigned char inbuf[16];
 187         char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
 188         char    *cp;
 189         size_t  words;
 190         u_char  *s;
 191
 192         if (bits < 0 || bits > 128) {
 193                 errno = EINVAL;
 194                 return (NULL);
 195         }
 196
 197         cp = outbuf;
 198
 199         if (bits == 0) {
 200                 *cp++ = ':';
 201                 *cp++ = ':';
 202                 *cp = '\0';
 203         } else {
 204                 /* Copy src to private buffer.  Zero host part. */
 205                 p = (bits + 7) / 8;
 206                 memcpy(inbuf, src, p);
 207                 memset(inbuf + p, 0, 16 - p);
 208                 b = bits % 8;
 209                 if (b != 0) {
 210                         m = ~0 << (8 - b);
 211                         inbuf[p-1] &= m;
 212                 }
 213
 214                 s = inbuf;
 215
 216                 /* how many words need to be displayed in output */
 217                 words = (bits + 15) / 16;
 218                 if (words == 1)
 219                         words = 2;
 220
 221                 /* Find the longest substring of zero's */
 222                 zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
 223                 for (i = 0; i < (words * 2); i += 2) {
 224                         if ((s[i] | s[i+1]) == 0) {
 225                                 if (tmp_zero_l == 0)
 226                                         tmp_zero_s = i / 2;
 227                                 tmp_zero_l++;
 228                         } else {
 229                                 if (tmp_zero_l && zero_l < tmp_zero_l) {
 230                                         zero_s = tmp_zero_s;
 231                                         zero_l = tmp_zero_l;
 232                                         tmp_zero_l = 0;
 233                                 }
 234                         }
 235                 }
 236
 237                 if (tmp_zero_l && zero_l < tmp_zero_l) {
 238                         zero_s = tmp_zero_s;
 239                         zero_l = tmp_zero_l;
 240                 }
 241
 242                 if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
 243                     ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
 244                     ((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
 245                         is_ipv4 = 1;
 246
 247                 /* Format whole words. */
 248                 for (p = 0; p < words; p++) {
 249                         if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) {
 250                                 /* Time to skip some zeros */
 251                                 if (p == zero_s)
 252                                         *cp++ = ':';
 253                                 if (p == words - 1)
 254                                         *cp++ = ':';
 255                                 s++;
 256                                 s++;
 257                                 continue;
 258                         }
 259
 260                         if (is_ipv4 && p > 5 ) {
 261                                 *cp++ = (p == 6) ? ':' : '.';
 262                                 cp += SPRINTF((cp, "%u", *s++));
 263                                 /* we can potentially drop the last octet */
 264                                 if (p != 7 || bits > 120) {
 265                                         *cp++ = '.';
 266                                         cp += SPRINTF((cp, "%u", *s++));
 267                                 }
 268                         } else {
 269                                 if (cp != outbuf)
 270                                         *cp++ = ':';
 271                                 cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
 272                                 s += 2;
 273                         }
 274                 }
 275         }
 276         /* Format CIDR /width. */
 277         (void)SPRINTF((cp, "/%u", bits));
 278         if (strlen(outbuf) + 1 > size)
 279                 goto emsgsize;
 280         strcpy(dst, outbuf);
 281
 282         return (dst);
 283
 284 emsgsize:
 285         errno = EMSGSIZE;
 286         return (NULL);
 287 }