external/bsd/ntp/dist/lib/isc/inet_ntop.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (C) 1996-2001  Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and/or distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  12  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  13  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  14  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  15  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  16  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  17  * PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 /*! \file */
  21
  22 #if defined(LIBC_SCCS) && !defined(lint)
  23 static char rcsid[] =
  24         "Id: inet_ntop.c,v 1.19 2007/06/19 23:47:17 tbox Exp";
  25 #endif /* LIBC_SCCS and not lint */
  26
  27 #include <config.h>
  28
  29 #include <errno.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32
  33 #include <isc/net.h>
  34 #include <isc/print.h>
  35
  36 #include "ntp_sprintf.h"        /* NTP local change, helps SunOS 4 */
  37
  38 #define NS_INT16SZ       2
  39 #define NS_IN6ADDRSZ    16
  40
  41 /*
  42  * WARNING: Don't even consider trying to compile this on a system where
  43  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  44  */
  45
  46 static const char *inet_ntop4(const unsigned char *src, char *dst,
  47                               size_t size);
  48
  49 #ifdef AF_INET6
  50 static const char *inet_ntop6(const unsigned char *src, char *dst,
  51                               size_t size);
  52 #endif
  53
  54 /*! char *
  55  * isc_net_ntop(af, src, dst, size)
  56  *      convert a network format address to presentation format.
  57  * \return
  58  *      pointer to presentation format address (`dst'), or NULL (see errno).
  59  * \author
  60  *      Paul Vixie, 1996.
  61  */
  62 const char *
  63 isc_net_ntop(int af, const void *src, char *dst, size_t size)
  64 {
  65         switch (af) {
  66         case AF_INET:
  67                 return (inet_ntop4(src, dst, size));
  68 #ifdef AF_INET6
  69         case AF_INET6:
  70                 return (inet_ntop6(src, dst, size));
  71 #endif
  72         default:
  73                 errno = EAFNOSUPPORT;
  74                 return (NULL);
  75         }
  76         /* NOTREACHED */
  77 }
  78
  79 /*! const char *
  80  * inet_ntop4(src, dst, size)
  81  *      format an IPv4 address
  82  * \return
  83  *      `dst' (as a const)
  84  * \note
  85  *      (1) uses no statics
  86  * \note
  87  *      (2) takes a unsigned char* not an in_addr as input
  88  * \author
  89  *      Paul Vixie, 1996.
  90  */
  91 static const char *
  92 inet_ntop4(const unsigned char *src, char *dst, size_t size)
  93 {
  94         static const char *fmt = "%u.%u.%u.%u";
  95         char tmp[sizeof("255.255.255.255")];
  96
  97         /* NTP local change to use SNPRINTF() macro for SunOS4 compat */
  98         if (SNPRINTF((tmp, sizeof(tmp), fmt, src[0], src[1], src[2],
  99                       src[3])) >= size)
 100         {
 101                 errno = ENOSPC;
 102                 return (NULL);
 103         }
 104         strcpy(dst, tmp);
 105
 106         return (dst);
 107 }
 108
 109 /*! const char *
 110  * isc_inet_ntop6(src, dst, size)
 111  *      convert IPv6 binary address into presentation (printable) format
 112  * \author
 113  *      Paul Vixie, 1996.
 114  */
 115 #ifdef AF_INET6
 116 static const char *
 117 inet_ntop6(const unsigned char *src, char *dst, size_t size)
 118 {
 119         /*
 120          * Note that int32_t and int16_t need only be "at least" large enough
 121          * to contain a value of the specified size.  On some systems, like
 122          * Crays, there is no such thing as an integer variable with 16 bits.
 123          * Keep this in mind if you think this function should have been coded
 124          * to use pointer overlays.  All the world's not a VAX.
 125          */
 126         char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
 127         struct { int base, len; } best, cur;
 128         unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
 129         int i;
 130
 131         /*
 132          * Preprocess:
 133          *      Copy the input (bytewise) array into a wordwise array.
 134          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 135          */
 136         memset(words, '\0', sizeof(words));
 137         for (i = 0; i < NS_IN6ADDRSZ; i++)
 138                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 139         best.base = -1;
 140         cur.base = -1;
 141         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 142                 if (words[i] == 0) {
 143                         if (cur.base == -1)
 144                                 cur.base = i, cur.len = 1;
 145                         else
 146                                 cur.len++;
 147                 } else {
 148                         if (cur.base != -1) {
 149                                 if (best.base == -1 || cur.len > best.len)
 150                                         best = cur;
 151                                 cur.base = -1;
 152                         }
 153                 }
 154         }
 155         if (cur.base != -1) {
 156                 if (best.base == -1 || cur.len > best.len)
 157                         best = cur;
 158         }
 159         if (best.base != -1 && best.len < 2)
 160                 best.base = -1;
 161
 162         /*
 163          * Format the result.
 164          */
 165         tp = tmp;
 166         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 167                 /* Are we inside the best run of 0x00's? */
 168                 if (best.base != -1 && i >= best.base &&
 169                     i < (best.base + best.len)) {
 170                         if (i == best.base)
 171                                 *tp++ = ':';
 172                         continue;
 173                 }
 174                 /* Are we following an initial run of 0x00s or any real hex? */
 175                 if (i != 0)
 176                         *tp++ = ':';
 177                 /* Is this address an encapsulated IPv4? */
 178                 if (i == 6 && best.base == 0 &&
 179                     (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 180                         if (!inet_ntop4(src+12, tp,
 181                                         sizeof(tmp) - (tp - tmp)))
 182                                 return (NULL);
 183                         tp += strlen(tp);
 184                         break;
 185                 }
 186                 tp += SPRINTF((tp, "%x", words[i]));    /* NTP local change */
 187         }
 188         /* Was it a trailing run of 0x00's? */
 189         if (best.base != -1 && (best.base + best.len) ==
 190             (NS_IN6ADDRSZ / NS_INT16SZ))
 191                 *tp++ = ':';
 192         *tp++ = '\0';
 193
 194         /*
 195          * Check for overflow, copy, and we're done.
 196          */
 197         if ((size_t)(tp - tmp) > size) {
 198                 errno = ENOSPC;
 199                 return (NULL);
 200         }
 201         strcpy(dst, tmp);
 202         return (dst);
 203 }
 204 #endif /* AF_INET6 */