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 1.3 2012/03/20 17:08:13 matt 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(const u_char *src, int bits,
  53                                         char *dst, size_t size);
  54 static char *   inet_net_ntop_ipv6(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(int af, const void *src, int bits, char *dst, size_t size)
  69 {
  70         switch (af) {
  71         case AF_INET:
  72                 return (inet_net_ntop_ipv4(src, bits, dst, size));
  73         case AF_INET6:
  74                 return (inet_net_ntop_ipv6(src, bits, dst, size));
  75         default:
  76                 errno = EAFNOSUPPORT;
  77                 return (NULL);
  78         }
  79 }
  80
  81 /*
  82  * static char *
  83  * inet_net_ntop_ipv4(src, bits, dst, size)
  84  *      convert IPv4 network number from network to presentation format.
  85  *      generates CIDR style result always.
  86  * return:
  87  *      pointer to dst, or NULL if an error occurred (check errno).
  88  * note:
  89  *      network byte order assumed.  this means 192.5.5.240/28 has
  90  *      0b11110000 in its fourth octet.
  91  * author:
  92  *      Paul Vixie (ISC), July 1996
  93  */
  94 static char *
  95 inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)
  96 {
  97         char *odst = dst;
  98         char *t;
  99         u_int m;
 100         int b;
 101
 102         if (bits < 0 || bits > 32) {
 103                 errno = EINVAL;
 104                 return (NULL);
 105         }
 106
 107         if (bits == 0) {
 108                 if (size < sizeof "0")
 109                         goto emsgsize;
 110                 *dst++ = '0';
 111                 size--;
 112                 *dst = '\0';
 113         }
 114
 115         /* Format whole octets. */
 116         for (b = bits / 8; b > 0; b--) {
 117                 if (size <= sizeof "255.")
 118                         goto emsgsize;
 119                 t = dst;
 120                 dst += SPRINTF((dst, "%u", *src++));
 121                 if (b > 1) {
 122                         *dst++ = '.';
 123                         *dst = '\0';
 124                 }
 125                 size -= (size_t)(dst - t);
 126         }
 127
 128         /* Format partial octet. */
 129         b = bits % 8;
 130         if (b > 0) {
 131                 if (size <= sizeof ".255")
 132                         goto emsgsize;
 133                 t = dst;
 134                 if (dst != odst)
 135                         *dst++ = '.';
 136                 m = ((1 << b) - 1) << (8 - b);
 137                 dst += SPRINTF((dst, "%u", *src & m));
 138                 size -= (size_t)(dst - t);
 139         }
 140
 141         /* Format CIDR /width. */
 142         if (size <= sizeof "/32")
 143                 goto emsgsize;
 144         dst += SPRINTF((dst, "/%u", bits));
 145         return (odst);
 146
 147  emsgsize:
 148         errno = EMSGSIZE;
 149         return (NULL);
 150 }
 151
 152 /*
 153  * static char *
 154  * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
 155  *      convert IPv6 network number from network to presentation format.
 156  *      generates CIDR style result always. Picks the shortest representation
 157  *      unless the IP is really IPv4.
 158  *      always prints specified number of bits (bits).
 159  * return:
 160  *      pointer to dst, or NULL if an error occurred (check errno).
 161  * note:
 162  *      network byte order assumed.  this means 192.5.5.240/28 has
 163  *      0x11110000 in its fourth octet.
 164  * author:
 165  *      Vadim Kogan (UCB), June 2001
 166  *  Original version (IPv4) by Paul Vixie (ISC), July 1996
 167  */
 168
 169 static char *
 170 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size)
 171 {
 172         u_int   m;
 173         int     b;
 174         size_t  p;
 175         size_t  zero_s, zero_l, tmp_zero_s, tmp_zero_l;
 176         size_t  i;
 177         int     is_ipv4 = 0;
 178         unsigned char inbuf[16];
 179         char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
 180         char    *cp;
 181         size_t  words;
 182         u_char  *s;
 183
 184         if (bits < 0 || bits > 128) {
 185                 errno = EINVAL;
 186                 return (NULL);
 187         }
 188
 189         cp = outbuf;
 190
 191         if (bits == 0) {
 192                 *cp++ = ':';
 193                 *cp++ = ':';
 194                 *cp = '\0';
 195         } else {
 196                 /* Copy src to private buffer.  Zero host part. */
 197                 p = (bits + 7) / 8;
 198                 memcpy(inbuf, src, p);
 199                 memset(inbuf + p, 0, 16 - p);
 200                 b = bits % 8;
 201                 if (b != 0) {
 202                         m = ~0 << (8 - b);
 203                         inbuf[p-1] &= m;
 204                 }
 205
 206                 s = inbuf;
 207
 208                 /* how many words need to be displayed in output */
 209                 words = (bits + 15) / 16;
 210                 if (words == 1)
 211                         words = 2;
 212
 213                 /* Find the longest substring of zero's */
 214                 zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
 215                 for (i = 0; i < (words * 2); i += 2) {
 216                         if ((s[i] | s[i+1]) == 0) {
 217                                 if (tmp_zero_l == 0)
 218                                         tmp_zero_s = i / 2;
 219                                 tmp_zero_l++;
 220                         } else {
 221                                 if (tmp_zero_l && zero_l < tmp_zero_l) {
 222                                         zero_s = tmp_zero_s;
 223                                         zero_l = tmp_zero_l;
 224                                         tmp_zero_l = 0;
 225                                 }
 226                         }
 227                 }
 228
 229                 if (tmp_zero_l && zero_l < tmp_zero_l) {
 230                         zero_s = tmp_zero_s;
 231                         zero_l = tmp_zero_l;
 232                 }
 233
 234                 if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
 235                     ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
 236                     ((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
 237                         is_ipv4 = 1;
 238
 239                 /* Format whole words. */
 240                 for (p = 0; p < words; p++) {
 241                         if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) {
 242                                 /* Time to skip some zeros */
 243                                 if (p == zero_s)
 244                                         *cp++ = ':';
 245                                 if (p == words - 1)
 246                                         *cp++ = ':';
 247                                 s++;
 248                                 s++;
 249                                 continue;
 250                         }
 251
 252                         if (is_ipv4 && p > 5 ) {
 253                                 *cp++ = (p == 6) ? ':' : '.';
 254                                 cp += SPRINTF((cp, "%u", *s++));
 255                                 /* we can potentially drop the last octet */
 256                                 if (p != 7 || bits > 120) {
 257                                         *cp++ = '.';
 258                                         cp += SPRINTF((cp, "%u", *s++));
 259                                 }
 260                         } else {
 261                                 if (cp != outbuf)
 262                                         *cp++ = ':';
 263                                 cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
 264                                 s += 2;
 265                         }
 266                 }
 267         }
 268         /* Format CIDR /width. */
 269         (void)SPRINTF((cp, "/%u", bits));
 270         if (strlen(outbuf) + 1 > size)
 271                 goto emsgsize;
 272         strcpy(dst, outbuf);
 273
 274         return (dst);
 275
 276 emsgsize:
 277         errno = EMSGSIZE;
 278         return (NULL);
 279 }