net/FreeBSD/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 1.3.18.2 2006/06/20 02:51:32 marka Exp $";
  20 #endif
  21 #include <sys/cdefs.h>
  22 __FBSDID("$FreeBSD: src/lib/libc/inet/inet_net_ntop.c,v 1.4 2007/06/03 17:20:26 ume Exp $");
  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/inet.h>
  30
  31 #include <errno.h>
  32 #include <stdio.h>
  33 #include <string.h>
  34 #include <stdlib.h>
  35
  36 #include "port_after.h"
  37
  38 #ifdef SPRINTF_CHAR
  39 # define SPRINTF(x) strlen(sprintf/**/x)
  40 #else
  41 # define SPRINTF(x) ((size_t)sprintf x)
  42 #endif
  43
  44 static char *   inet_net_ntop_ipv4(const u_char *src, int bits, char *dst,
  45                     size_t size);
  46 static char *   inet_net_ntop_ipv6(const u_char *src, int bits, char *dst,
  47                     size_t size);
  48
  49 /*%
  50  * char *
  51  * inet_net_ntop(af, src, bits, dst, size)
  52  *      convert network number from network to presentation format.
  53  *      generates CIDR style result always.
  54  * return:
  55  *      pointer to dst, or NULL if an error occurred (check errno).
  56  * author:
  57  *      Paul Vixie (ISC), July 1996
  58  */
  59 char *
  60 inet_net_ntop(af, src, bits, dst, size)
  61         int af;
  62         const void *src;
  63         int bits;
  64         char *dst;
  65         size_t size;
  66 {
  67         switch (af) {
  68         case AF_INET:
  69                 return (inet_net_ntop_ipv4(src, bits, dst, size));
  70         case AF_INET6:
  71                 return (inet_net_ntop_ipv6(src, bits, dst, size));
  72         default:
  73                 errno = EAFNOSUPPORT;
  74                 return (NULL);
  75         }
  76 }
  77
  78 /*%
  79  * static char *
  80  * inet_net_ntop_ipv4(src, bits, dst, size)
  81  *      convert IPv4 network number from network to presentation format.
  82  *      generates CIDR style result always.
  83  * return:
  84  *      pointer to dst, or NULL if an error occurred (check errno).
  85  * note:
  86  *      network byte order assumed.  this means 192.5.5.240/28 has
  87  *      0b11110000 in its fourth octet.
  88  * author:
  89  *      Paul Vixie (ISC), July 1996
  90  */
  91 static char *
  92 inet_net_ntop_ipv4(src, bits, dst, size)
  93         const u_char *src;
  94         int bits;
  95         char *dst;
  96         size_t size;
  97 {
  98         char *odst = dst;
  99         char *t;
 100         u_int m;
 101         int b;
 102
 103         if (bits < 0 || bits > 32) {
 104                 errno = EINVAL;
 105                 return (NULL);
 106         }
 107
 108         if (bits == 0) {
 109                 if (size < sizeof "0")
 110                         goto emsgsize;
 111                 *dst++ = '0';
 112                 size--;
 113                 *dst = '\0';
 114         }
 115
 116         /* Format whole octets. */
 117         for (b = bits / 8; b > 0; b--) {
 118                 if (size <= sizeof "255.")
 119                         goto emsgsize;
 120                 t = dst;
 121                 dst += SPRINTF((dst, "%u", *src++));
 122                 if (b > 1) {
 123                         *dst++ = '.';
 124                         *dst = '\0';
 125                 }
 126                 size -= (size_t)(dst - t);
 127         }
 128
 129         /* Format partial octet. */
 130         b = bits % 8;
 131         if (b > 0) {
 132                 if (size <= sizeof ".255")
 133                         goto emsgsize;
 134                 t = dst;
 135                 if (dst != odst)
 136                         *dst++ = '.';
 137                 m = ((1 << b) - 1) << (8 - b);
 138                 dst += SPRINTF((dst, "%u", *src & m));
 139                 size -= (size_t)(dst - t);
 140         }
 141
 142         /* Format CIDR /width. */
 143         if (size <= sizeof "/32")
 144                 goto emsgsize;
 145         dst += SPRINTF((dst, "/%u", bits));
 146         return (odst);
 147
 148  emsgsize:
 149         errno = EMSGSIZE;
 150         return (NULL);
 151 }
 152
 153 /*%
 154  * static char *
 155  * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
 156  *      convert IPv6 network number from network to presentation format.
 157  *      generates CIDR style result always. Picks the shortest representation
 158  *      unless the IP is really IPv4.
 159  *      always prints specified number of bits (bits).
 160  * return:
 161  *      pointer to dst, or NULL if an error occurred (check errno).
 162  * note:
 163  *      network byte order assumed.  this means 192.5.5.240/28 has
 164  *      0b11110000 in its fourth octet.
 165  * author:
 166  *      Vadim Kogan (UCB), June 2001
 167  *  Original version (IPv4) by Paul Vixie (ISC), July 1996
 168  */
 169
 170 static char *
 171 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
 172         u_int   m;
 173         int     b;
 174         int     p;
 175         int     zero_s, zero_l, tmp_zero_s, tmp_zero_l;
 176         int     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         int     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         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 }
 280
 281 /*
 282  * Weak aliases for applications that use certain private entry points,
 283  * and fail to include <arpa/inet.h>.
 284  */
 285 #undef inet_net_ntop
 286 __weak_reference(__inet_net_ntop, inet_net_ntop);
 287
 288 /*! \file */