compat/inet_ntop.c

   1 /*
   2  *  Shamelessly duplicated from the bind9 public sources
   3  *  for use by the Squid Project under ISC written permission
   4  *  included "as found" below.
   5  *
   6  * Update/Maintenance History:
   7  *
   8  *    24-Sep-2007 : Copied from bind 9.3.3
   9  *                      - Added protection around libray headers
  10  *                      - Altered configure checks
  11  *                      - Un-hacked slightly to use system gethostbyname()
  12  *
  13  *    06-Oct-2007 : Various fixes to allow the build on MinGW
  14  *
  15  *    28-Oct-2007: drop some dead code. now tested working without.
  16  *
  17  *    04-Nov-2010: drop SPRINTF casting macro
  18  *
  19  * Squid CVS $Id$
  20  *
  21  *  Original License and code follows.
  22  */
  23
  24 #include "config.h"
  25
  26 #if !HAVE_INET_NTOP
  27 #include "inet_ntop.h"
  28
  29 /*
  30  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
  31  * Copyright (c) 1996-1999 by Internet Software Consortium.
  32  *
  33  * Permission to use, copy, modify, and distribute this software for any
  34  * purpose with or without fee is hereby granted, provided that the above
  35  * copyright notice and this permission notice appear in all copies.
  36  *
  37  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  38  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  39  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  40  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  41  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  42  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  43  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  44  */
  45
  46 #if defined(LIBC_SCCS) && !defined(lint)
  47 static const char rcsid[] = "inet_ntop.c,v 1.1.2.1.8.2 2005/11/03 23:08:40 marka Exp";
  48 #endif /* LIBC_SCCS and not lint */
  49
  50 #if HAVE_SYS_PARAM_H
  51 #include <sys/param.h>
  52 #endif
  53 #if HAVE_SYS_TYPES_H
  54 #include <sys/types.h>
  55 #endif
  56 #if HAVE_SYS_SOCKET_H
  57 #include <sys/socket.h>
  58 #endif
  59
  60 #if HAVE_NETINET_IN_H
  61 #include <netinet/in.h>
  62 #endif
  63 #if HAVE_ARPA_INET_H
  64 #include <arpa/inet.h>
  65 #endif
  66 #if HAVE_ARPA_NAMESER_H
  67 #include <arpa/nameser.h>
  68 #endif
  69
  70 #if HAVE_ERRNO_H
  71 #include <errno.h>
  72 #endif
  73 #if HAVE_STRING_H
  74 #include <string.h>
  75 #endif
  76
  77 #if ! defined(NS_INADDRSZ)
  78 #define NS_INADDRSZ      4
  79 #endif
  80 #if ! defined(NS_IN6ADDRSZ)
  81 #define NS_IN6ADDRSZ    16
  82 #endif
  83 #if ! defined(NS_INT16SZ)
  84 #define NS_INT16SZ      2
  85 #endif
  86
  87 /*
  88  * WARNING: Don't even consider trying to compile this on a system where
  89  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  90  */
  91
  92 static const char *inet_ntop4 (const u_char *src, char *dst, size_t size);
  93 static const char *inet_ntop6 (const u_char *src, char *dst, size_t size);
  94
  95 /* char *
  96  * inet_ntop(af, src, dst, size)
  97  *      convert a network format address to presentation format.
  98  * return:
  99  *      pointer to presentation format address (`dst'), or NULL (see errno).
 100  * author:
 101  *      Paul Vixie, 1996.
 102  */
 103 const char *
 104 xinet_ntop(af, src, dst, size)
 105 int af;
 106 const void *src;
 107 char *dst;
 108 size_t size;
 109 {
 110     switch (af) {
 111     case AF_INET:
 112         return (inet_ntop4(src, dst, size));
 113     case AF_INET6:
 114         return (inet_ntop6(src, dst, size));
 115     default:
 116         errno = EAFNOSUPPORT;
 117         return (NULL);
 118     }
 119     /* NOTREACHED */
 120 }
 121
 122 /* const char *
 123  * inet_ntop4(src, dst, size)
 124  *      format an IPv4 address
 125  * return:
 126  *      `dst' (as a const)
 127  * notes:
 128  *      (1) uses no statics
 129  *      (2) takes a u_char* not an in_addr as input
 130  * author:
 131  *      Paul Vixie, 1996.
 132  */
 133 static const char *
 134 inet_ntop4(src, dst, size)
 135 const u_char *src;
 136 char *dst;
 137 size_t size;
 138 {
 139     static const char fmt[] = "%u.%u.%u.%u";
 140     char tmp[sizeof "255.255.255.255"];
 141
 142     if (snprintf(tmp, min(sizeof("255.255.255.255"),size), fmt, src[0], src[1], src[2], src[3]) >= size) {
 143         errno = ENOSPC;
 144         return (NULL);
 145     }
 146     strcpy(dst, tmp);
 147     return (dst);
 148 }
 149
 150 /* const char *
 151  * inet_ntop6(src, dst, size)
 152  *      convert IPv6 binary address into presentation (printable) format
 153  * author:
 154  *      Paul Vixie, 1996.
 155  */
 156 static const char *
 157 inet_ntop6(src, dst, size)
 158 const u_char *src;
 159 char *dst;
 160 size_t size;
 161 {
 162     /*
 163      * Note that int32_t and int16_t need only be "at least" large enough
 164      * to contain a value of the specified size.  On some systems, like
 165      * Crays, there is no such thing as an integer variable with 16 bits.
 166      * Keep this in mind if you think this function should have been coded
 167      * to use pointer overlays.  All the world's not a VAX.
 168      */
 169     char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
 170     struct { int base, len; } best, cur;
 171     u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
 172     int i;
 173
 174     /*
 175      * Preprocess:
 176      *  Copy the input (bytewise) array into a wordwise array.
 177      *  Find the longest run of 0x00's in src[] for :: shorthanding.
 178      */
 179     memset(words, '\0', sizeof words);
 180     for (i = 0; i < NS_IN6ADDRSZ; i++)
 181         words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
 182     best.base = -1;
 183     best.len = 0;
 184     cur.base = -1;
 185     cur.len = 0;
 186     for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 187         if (words[i] == 0) {
 188             if (cur.base == -1)
 189                 cur.base = i, cur.len = 1;
 190             else
 191                 cur.len++;
 192         } else {
 193             if (cur.base != -1) {
 194                 if (best.base == -1 || cur.len > best.len)
 195                     best = cur;
 196                 cur.base = -1;
 197             }
 198         }
 199     }
 200     if (cur.base != -1) {
 201         if (best.base == -1 || cur.len > best.len)
 202             best = cur;
 203     }
 204     if (best.base != -1 && best.len < 2)
 205         best.base = -1;
 206
 207     /*
 208      * Format the result.
 209      */
 210     tp = tmp;
 211     for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
 212         /* Are we inside the best run of 0x00's? */
 213         if (best.base != -1 && i >= best.base &&
 214                 i < (best.base + best.len)) {
 215             if (i == best.base)
 216                 *tp++ = ':';
 217             continue;
 218         }
 219         /* Are we following an initial run of 0x00s or any real hex? */
 220         if (i != 0)
 221             *tp++ = ':';
 222         /* Is this address an encapsulated IPv4? */
 223         if (i == 6 && best.base == 0 && (best.len == 6 ||
 224                                          (best.len == 7 && words[7] != 0x0001) ||
 225                                          (best.len == 5 && words[5] == 0xffff))) {
 226             if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
 227                 return (NULL);
 228             tp += strlen(tp);
 229             break;
 230         }
 231         tp += snprintf(tp, (tmp + sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255") - tp), "%x", words[i]);
 232     }
 233     /* Was it a trailing run of 0x00's? */
 234     if (best.base != -1 && (best.base + best.len) ==
 235             (NS_IN6ADDRSZ / NS_INT16SZ))
 236         *tp++ = ':';
 237     *tp++ = '\0';
 238
 239     /*
 240      * Check for overflow, copy, and we're done.
 241      */
 242     if ((size_t)(tp - tmp) > size) {
 243         errno = ENOSPC;
 244         return (NULL);
 245     }
 246     strcpy(dst, tmp);
 247     return (dst);
 248 }
 249
 250 #endif /* HAVE_INET_NTOP */