wsutil/inet_ntop.c

   1 /*
   2  * $Id$
   3  *
   4  * Copyright (c) 1996-1999 by Internet Software Consortium.
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  11  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  12  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  13  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  14  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  15  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  16  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  17  * SOFTWARE.
  18  */
  19
  20
  21 #include "config.h"
  22
  23 #ifdef HAVE_SYS_PARAM_H
  24 #include <sys/param.h>
  25 #endif
  26
  27 #ifdef HAVE_SYS_TYPES_H
  28 #include <sys/types.h>
  29 #endif
  30
  31 #ifdef HAVE_SYS_SOCKET_H
  32 #include <sys/socket.h>         /* needed to define AF_ values on UNIX */
  33 #endif
  34
  35 #ifdef HAVE_WINSOCK2_H
  36 #include <winsock2.h>   /* needed to define AF_ values on Windows */
  37 #if _MSC_VER < 1600     /* errno.h defines EAFNOSUPPORT in Windows VC10 (and presumably eventually in VC11 ...) */
  38 #define EAFNOSUPPORT    WSAEAFNOSUPPORT
  39 #endif
  40 #endif
  41
  42 #ifdef HAVE_NETINET_IN_H
  43 #include <netinet/in.h>
  44 #endif
  45
  46 #ifdef HAVE_ARPA_INET_H
  47 #include <arpa/inet.h>
  48 #endif
  49
  50 #ifdef HAVE_ARPA_NAMESER_H
  51 #include <arpa/nameser.h>
  52 #endif
  53
  54 #include <errno.h>
  55 #include <stdio.h>
  56 #include <string.h>
  57
  58 #include "inet_v6defs.h"
  59
  60 #include <glib.h>
  61
  62 #ifndef NS_INADDRSZ
  63 #define NS_INADDRSZ     4
  64 #endif
  65 #ifndef NS_IN6ADDRSZ
  66 #define NS_IN6ADDRSZ    16
  67 #endif
  68 #ifndef NS_INT16SZ
  69 #define NS_INT16SZ      2
  70 #endif
  71
  72 /*
  73  * WARNING: Don't even consider trying to compile this on a system where
  74  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  75  */
  76
  77 static const char *inet_ntop4 __P((const u_char *src, char *dst, size_t size));
  78 static const char *inet_ntop6 __P((const u_char *src, char *dst, size_t size));
  79
  80 /* char *
  81  * inet_ntop(af, src, dst, size)
  82  *      convert a network format address to presentation format.
  83  * return:
  84  *      pointer to presentation format address (`dst'), or NULL (see errno).
  85  * author:
  86  *      Paul Vixie, 1996.
  87  */
  88 const char *
  89 inet_ntop(af, src, dst, size)
  90         int af;
  91         const void *src;
  92         char *dst;
  93         size_t size;
  94 {
  95         switch (af) {
  96         case AF_INET:
  97                 return (inet_ntop4(src, dst, size));
  98         case AF_INET6:
  99                 return (inet_ntop6(src, dst, size));
 100         default:
 101                 errno = EAFNOSUPPORT;
 102                 return (NULL);
 103         }
 104         /* NOTREACHED */
 105 }
 106
 107 /* const char *
 108  * inet_ntop4(src, dst, size)
 109  *      format an IPv4 address
 110  * return:
 111  *      `dst' (as a const)
 112  * notes:
 113  *      (1) uses no statics
 114  *      (2) takes a u_char* not an in_addr as input
 115  * author:
 116  *      Paul Vixie, 1996.
 117  */
 118 static const char *
 119 inet_ntop4(src, dst, size)
 120         const u_char *src;
 121         char *dst;
 122         size_t size;
 123 {
 124         static const char fmt[] = "%u.%u.%u.%u";
 125         char tmp[sizeof "255.255.255.255"];
 126         int nprinted;
 127
 128         nprinted = g_snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
 129         /* Note: nprinted *excludes* the trailing '\0' character */
 130         if ((size_t)nprinted >= size) {
 131                 errno = ENOSPC;
 132                 return (NULL);
 133         }
 134         g_strlcpy(dst, tmp, size);
 135         return (dst);
 136 }
 137
 138 /* const char *
 139  * inet_ntop6(src, dst, size)
 140  *      convert IPv6 binary address into presentation (printable) format
 141  * author:
 142  *      Paul Vixie, 1996.
 143  */
 144 static const char *
 145 inet_ntop6(src, dst, size)
 146         const u_char *src;
 147         char *dst;
 148         size_t size;
 149 {
 150         /*
 151          * Note that int32_t and int16_t need only be "at least" large enough
 152          * to contain a value of the specified size.  On some systems, like
 153          * Crays, there is no such thing as an integer variable with 16 bits.
 154          * Keep this in mind if you think this function should have been coded
 155          * to use pointer overlays.  All the world's not a VAX.
 156          */
 157         char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
 158         struct { int base, len; } best, cur;
 159         u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
 160         int i;
 161
 162         /*
 163          * Preprocess:
 164          *      Copy the input (bytewise) array into a wordwise array.
 165          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 166          */
 167         memset(words, '\0', sizeof words);
 168         for (i = 0; i < NS_IN6ADDRSZ; i++)
 169                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 170         best.base = -1;
 171         cur.base = -1;
 172         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 173                 if (words[i] == 0) {
 174                         if (cur.base == -1)
 175                                 cur.base = i, cur.len = 1;
 176                         else
 177                                 cur.len++;
 178                 } else {
 179                         if (cur.base != -1) {
 180                                 if (best.base == -1 || cur.len > best.len)
 181                                         best = cur;
 182                                 cur.base = -1;
 183                         }
 184                 }
 185         }
 186         if (cur.base != -1) {
 187                 if (best.base == -1 || cur.len > best.len)
 188                         best = cur;
 189         }
 190         if (best.base != -1 && best.len < 2)
 191                 best.base = -1;
 192
 193         /*
 194          * Format the result.
 195          */
 196         tp = tmp;
 197         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 198                 /* Are we inside the best run of 0x00's? */
 199                 if (best.base != -1 && i >= best.base &&
 200                     i < (best.base + best.len)) {
 201                         if (i == best.base)
 202                                 *tp++ = ':';
 203                         continue;
 204                 }
 205                 /* Are we following an initial run of 0x00s or any real hex? */
 206                 if (i != 0)
 207                         *tp++ = ':';
 208                 /* Is this address an encapsulated IPv4? */
 209                 if (i == 6 && best.base == 0 &&
 210                     (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 211                         if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 212                                 return (NULL);
 213                         tp += strlen(tp);
 214                         break;
 215                 }
 216                 tp += g_snprintf(tp, (gulong) (sizeof tmp - (tp - tmp)), "%x", words[i]);
 217         }
 218         /* Was it a trailing run of 0x00's? */
 219         if (best.base != -1 && (best.base + best.len) ==
 220             (NS_IN6ADDRSZ / NS_INT16SZ))
 221                 *tp++ = ':';
 222         *tp++ = '\0';
 223
 224         /*
 225          * Check for overflow, copy, and we're done.
 226          */
 227         if ((size_t)(tp - tmp) > size) {
 228                 errno = ENOSPC;
 229                 return (NULL);
 230         }
 231         g_strlcpy(dst, tmp, size);
 232         return (dst);
 233 }