contrib/bind-9.5.2/lib/lwres/lwinetntop.c

   1 /*
   2  * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1996-2001, 2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or 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 WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /*! \file lwinetntop.c
  19  */
  20 #if defined(LIBC_SCCS) && !defined(lint)
  21 static char rcsid[] =
  22         "$Id: lwinetntop.c,v 1.18 2007/06/19 23:47:22 tbox Exp $";
  23 #endif /* LIBC_SCCS and not lint */
  24
  25 #include <config.h>
  26
  27 #include <errno.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30
  31 #include <lwres/net.h>
  32 #include "print_p.h"
  33
  34 #define NS_INT16SZ       2
  35 #define NS_IN6ADDRSZ    16
  36
  37 /*
  38  * WARNING: Don't even consider trying to compile this on a system where
  39  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  40  */
  41
  42 static const char *inet_ntop4(const unsigned char *src, char *dst,
  43                               size_t size);
  44
  45 #ifdef AF_INET6
  46 static const char *inet_ntop6(const unsigned char *src, char *dst,
  47                               size_t size);
  48 #endif
  49
  50 /*! char *
  51  * lwres_net_ntop(af, src, dst, size)
  52  *      convert a network format address to presentation format.
  53  * return:
  54  *      pointer to presentation format address (`dst'), or NULL (see errno).
  55  * author:
  56  *      Paul Vixie, 1996.
  57  */
  58 const char *
  59 lwres_net_ntop(int af, const void *src, char *dst, size_t size) {
  60         switch (af) {
  61         case AF_INET:
  62                 return (inet_ntop4(src, dst, size));
  63 #ifdef AF_INET6
  64         case AF_INET6:
  65                 return (inet_ntop6(src, dst, size));
  66 #endif
  67         default:
  68                 errno = EAFNOSUPPORT;
  69                 return (NULL);
  70         }
  71         /* NOTREACHED */
  72 }
  73
  74 /*! const char *
  75  * inet_ntop4(src, dst, size)
  76  *      format an IPv4 address
  77  * return:
  78  *      `dst' (as a const)
  79  * notes:
  80  *      (1) uses no statics
  81  *      (2) takes a unsigned char* not an in_addr as input
  82  * author:
  83  *      Paul Vixie, 1996.
  84  */
  85 static const char *
  86 inet_ntop4(const unsigned char *src, char *dst, size_t size) {
  87         static const char fmt[] = "%u.%u.%u.%u";
  88         char tmp[sizeof("255.255.255.255")];
  89         size_t len;
  90
  91         len = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
  92         if (len >= size) {
  93                 errno = ENOSPC;
  94                 return (NULL);
  95         }
  96         strcpy(dst, tmp);
  97
  98         return (dst);
  99 }
 100
 101 /*! const char *
 102  * inet_ntop6(src, dst, size)
 103  *      convert IPv6 binary address into presentation (printable) format
 104  * author:
 105  *      Paul Vixie, 1996.
 106  */
 107 #ifdef AF_INET6
 108 static const char *
 109 inet_ntop6(const unsigned char *src, char *dst, size_t size) {
 110         /*!
 111          * Note that int32_t and int16_t need only be "at least" large enough
 112          * to contain a value of the specified size.  On some systems, like
 113          * Crays, there is no such thing as an integer variable with 16 bits.
 114          * Keep this in mind if you think this function should have been coded
 115          * to use pointer overlays.  All the world's not a VAX.
 116          */
 117         char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
 118         struct { int base, len; } best, cur;
 119         unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
 120         int i;
 121
 122         /*
 123          * Preprocess:
 124          *      Copy the input (bytewise) array into a wordwise array.
 125          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 126          */
 127         memset(words, '\0', sizeof(words));
 128         for (i = 0; i < NS_IN6ADDRSZ; i++)
 129                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 130         best.base = -1;
 131         best.len = 0;
 132         cur.base = -1;
 133         cur.len = 0;
 134         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 135                 if (words[i] == 0) {
 136                         if (cur.base == -1)
 137                                 cur.base = i, cur.len = 1;
 138                         else
 139                                 cur.len++;
 140                 } else {
 141                         if (cur.base != -1) {
 142                                 if (best.base == -1 || cur.len > best.len)
 143                                         best = cur;
 144                                 cur.base = -1;
 145                         }
 146                 }
 147         }
 148         if (cur.base != -1) {
 149                 if (best.base == -1 || cur.len > best.len)
 150                         best = cur;
 151         }
 152         if (best.base != -1 && best.len < 2)
 153                 best.base = -1;
 154
 155         /*
 156          * Format the result.
 157          */
 158         tp = tmp;
 159         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 160                 /* Are we inside the best run of 0x00's? */
 161                 if (best.base != -1 && i >= best.base &&
 162                     i < (best.base + best.len)) {
 163                         if (i == best.base)
 164                                 *tp++ = ':';
 165                         continue;
 166                 }
 167                 /* Are we following an initial run of 0x00s or any real hex? */
 168                 if (i != 0)
 169                         *tp++ = ':';
 170                 /* Is this address an encapsulated IPv4? */
 171                 if (i == 6 && best.base == 0 &&
 172                     (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 173                         if (!inet_ntop4(src+12, tp,
 174                                         sizeof(tmp) - (tp - tmp)))
 175                                 return (NULL);
 176                         tp += strlen(tp);
 177                         break;
 178                 }
 179                 tp += sprintf(tp, "%x", words[i]); /* XXX */
 180         }
 181         /* Was it a trailing run of 0x00's? */
 182         if (best.base != -1 && (best.base + best.len) ==
 183             (NS_IN6ADDRSZ / NS_INT16SZ))
 184                 *tp++ = ':';
 185         *tp++ = '\0';
 186
 187         /*
 188          * Check for overflow, copy, and we're done.
 189          */
 190         if ((size_t)(tp - tmp) > size) {
 191                 errno = ENOSPC;
 192                 return (NULL);
 193         }
 194         strcpy(dst, tmp);
 195         return (dst);
 196 }
 197 #endif /* AF_INET6 */