external/bsd/bind/dist/lib/lwres/lwinetntop.c

   1 /*      $NetBSD: lwinetntop.c,v 1.4 2014/12/10 04:38:02 christos Exp $  */
   2
   3 /*
   4  * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (C) 1996-2001, 2003  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 lwinetntop.c
  21  */
  22 #if defined(LIBC_SCCS) && !defined(lint)
  23 static char rcsid[] =
  24         "Id: lwinetntop.c,v 1.18 2007/06/19 23:47:22 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 <lwres/net.h>
  34 #include "print_p.h"
  35
  36 #define NS_INT16SZ       2
  37 #define NS_IN6ADDRSZ    16
  38
  39 /*
  40  * WARNING: Don't even consider trying to compile this on a system where
  41  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  42  */
  43
  44 static const char *inet_ntop4(const unsigned char *src, char *dst,
  45                               size_t size);
  46
  47 #ifdef AF_INET6
  48 static const char *inet_ntop6(const unsigned char *src, char *dst,
  49                               size_t size);
  50 #endif
  51
  52 /*! char *
  53  * lwres_net_ntop(af, src, dst, size)
  54  *      convert a network format address to presentation format.
  55  * return:
  56  *      pointer to presentation format address (`dst'), or NULL (see errno).
  57  * author:
  58  *      Paul Vixie, 1996.
  59  */
  60 const char *
  61 lwres_net_ntop(int af, const void *src, char *dst, size_t size) {
  62         switch (af) {
  63         case AF_INET:
  64                 return (inet_ntop4(src, dst, size));
  65 #ifdef AF_INET6
  66         case AF_INET6:
  67                 return (inet_ntop6(src, dst, size));
  68 #endif
  69         default:
  70                 errno = EAFNOSUPPORT;
  71                 return (NULL);
  72         }
  73         /* NOTREACHED */
  74 }
  75
  76 /*! const char *
  77  * inet_ntop4(src, dst, size)
  78  *      format an IPv4 address
  79  * return:
  80  *      `dst' (as a const)
  81  * notes:
  82  *      (1) uses no statics
  83  *      (2) takes a unsigned char* not an in_addr as input
  84  * author:
  85  *      Paul Vixie, 1996.
  86  */
  87 static const char *
  88 inet_ntop4(const unsigned char *src, char *dst, size_t size) {
  89         static const char fmt[] = "%u.%u.%u.%u";
  90         char tmp[sizeof("255.255.255.255")];
  91         size_t len;
  92
  93         len = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
  94         if (len >= size) {
  95                 errno = ENOSPC;
  96                 return (NULL);
  97         }
  98         strcpy(dst, tmp);
  99
 100         return (dst);
 101 }
 102
 103 /*! const char *
 104  * inet_ntop6(src, dst, size)
 105  *      convert IPv6 binary address into presentation (printable) format
 106  * author:
 107  *      Paul Vixie, 1996.
 108  */
 109 #ifdef AF_INET6
 110 static const char *
 111 inet_ntop6(const unsigned char *src, char *dst, size_t size) {
 112         /*!
 113          * Note that int32_t and int16_t need only be "at least" large enough
 114          * to contain a value of the specified size.  On some systems, like
 115          * Crays, there is no such thing as an integer variable with 16 bits.
 116          * Keep this in mind if you think this function should have been coded
 117          * to use pointer overlays.  All the world's not a VAX.
 118          */
 119         char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
 120         struct { int base, len; } best, cur;
 121         unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
 122         int i;
 123
 124         /*
 125          * Preprocess:
 126          *      Copy the input (bytewise) array into a wordwise array.
 127          *      Find the longest run of 0x00's in src[] for :: shorthanding.
 128          */
 129         memset(words, '\0', sizeof(words));
 130         for (i = 0; i < NS_IN6ADDRSZ; i++)
 131                 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 132         best.base = -1;
 133         best.len = 0;
 134         cur.base = -1;
 135         cur.len = 0;
 136         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 137                 if (words[i] == 0) {
 138                         if (cur.base == -1)
 139                                 cur.base = i, cur.len = 1;
 140                         else
 141                                 cur.len++;
 142                 } else {
 143                         if (cur.base != -1) {
 144                                 if (best.base == -1 || cur.len > best.len)
 145                                         best = cur;
 146                                 cur.base = -1;
 147                         }
 148                 }
 149         }
 150         if (cur.base != -1) {
 151                 if (best.base == -1 || cur.len > best.len)
 152                         best = cur;
 153         }
 154         if (best.base != -1 && best.len < 2)
 155                 best.base = -1;
 156
 157         /*
 158          * Format the result.
 159          */
 160         tp = tmp;
 161         for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 162                 /* Are we inside the best run of 0x00's? */
 163                 if (best.base != -1 && i >= best.base &&
 164                     i < (best.base + best.len)) {
 165                         if (i == best.base)
 166                                 *tp++ = ':';
 167                         continue;
 168                 }
 169                 /* Are we following an initial run of 0x00s or any real hex? */
 170                 if (i != 0)
 171                         *tp++ = ':';
 172                 /* Is this address an encapsulated IPv4? */
 173                 if (i == 6 && best.base == 0 &&
 174                     (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
 175                         if (!inet_ntop4(src+12, tp,
 176                                         sizeof(tmp) - (tp - tmp)))
 177                                 return (NULL);
 178                         tp += strlen(tp);
 179                         break;
 180                 }
 181                 tp += sprintf(tp, "%x", words[i]); /* XXX */
 182         }
 183         /* Was it a trailing run of 0x00's? */
 184         if (best.base != -1 && (best.base + best.len) ==
 185             (NS_IN6ADDRSZ / NS_INT16SZ))
 186                 *tp++ = ':';
 187         *tp++ = '\0';
 188
 189         /*
 190          * Check for overflow, copy, and we're done.
 191          */
 192         if ((size_t)(tp - tmp) > size) {
 193                 errno = ENOSPC;
 194                 return (NULL);
 195         }
 196         strcpy(dst, tmp);
 197         return (dst);
 198 }
 199 #endif /* AF_INET6 */