release/src/router/tcpdump/missing/inet_ntop.c

   1 /*
   2  * Copyright (c) 1999 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by the Kungliga Tekniska
  20  *      Högskolan and its contributors.
  21  *
  22  * 4. Neither the name of the Institute nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 /* $Id: inet_ntop.c,v 1.8 2005-02-09 02:25:46 guy Exp $ */
  40
  41 #ifndef lint
  42 static const char rcsid[] _U_ =
  43      "@(#) $Header: /tcpdump/master/tcpdump/missing/inet_ntop.c,v 1.8 2005-02-09 02:25:46 guy Exp $";
  44 #endif
  45
  46 #include <tcpdump-stdinc.h>
  47
  48 #include <stdio.h>
  49 #include <errno.h>
  50
  51 /*
  52  *
  53  */
  54
  55 #ifndef IN6ADDRSZ
  56 #define IN6ADDRSZ   16   /* IPv6 T_AAAA */
  57 #endif
  58
  59 #ifndef INT16SZ
  60 #define INT16SZ     2    /* word size */
  61 #endif
  62
  63 static const char *
  64 inet_ntop_v4 (const void *src, char *dst, size_t size)
  65 {
  66     const char digits[] = "0123456789";
  67     int i;
  68     struct in_addr *addr = (struct in_addr *)src;
  69     u_long a = ntohl(addr->s_addr);
  70     const char *orig_dst = dst;
  71
  72     if (size < INET_ADDRSTRLEN) {
  73         errno = ENOSPC;
  74         return NULL;
  75     }
  76     for (i = 0; i < 4; ++i) {
  77         int n = (a >> (24 - i * 8)) & 0xFF;
  78         int non_zerop = 0;
  79
  80         if (non_zerop || n / 100 > 0) {
  81             *dst++ = digits[n / 100];
  82             n %= 100;
  83             non_zerop = 1;
  84         }
  85         if (non_zerop || n / 10 > 0) {
  86             *dst++ = digits[n / 10];
  87             n %= 10;
  88             non_zerop = 1;
  89         }
  90         *dst++ = digits[n];
  91         if (i != 3)
  92             *dst++ = '.';
  93     }
  94     *dst++ = '\0';
  95     return orig_dst;
  96 }
  97
  98 #ifdef INET6
  99 /*
 100  * Convert IPv6 binary address into presentation (printable) format.
 101  */
 102 static const char *
 103 inet_ntop_v6 (const u_char *src, char *dst, size_t size)
 104 {
 105   /*
 106    * Note that int32_t and int16_t need only be "at least" large enough
 107    * to contain a value of the specified size.  On some systems, like
 108    * Crays, there is no such thing as an integer variable with 16 bits.
 109    * Keep this in mind if you think this function should have been coded
 110    * to use pointer overlays.  All the world's not a VAX.
 111    */
 112   char  tmp [INET6_ADDRSTRLEN+1];
 113   char *tp;
 114   struct {
 115     long base;
 116     long len;
 117   } best, cur;
 118   u_long words [IN6ADDRSZ / INT16SZ];
 119   int    i;
 120
 121   /* Preprocess:
 122    *  Copy the input (bytewise) array into a wordwise array.
 123    *  Find the longest run of 0x00's in src[] for :: shorthanding.
 124    */
 125   memset (words, 0, sizeof(words));
 126   for (i = 0; i < IN6ADDRSZ; i++)
 127       words[i/2] |= (src[i] << ((1 - (i % 2)) << 3));
 128
 129   best.base = -1;
 130   cur.base  = -1;
 131   for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
 132   {
 133     if (words[i] == 0)
 134     {
 135       if (cur.base == -1)
 136            cur.base = i, cur.len = 1;
 137       else cur.len++;
 138     }
 139     else if (cur.base != -1)
 140     {
 141       if (best.base == -1 || cur.len > best.len)
 142          best = cur;
 143       cur.base = -1;
 144     }
 145   }
 146   if ((cur.base != -1) && (best.base == -1 || cur.len > best.len))
 147      best = cur;
 148   if (best.base != -1 && best.len < 2)
 149      best.base = -1;
 150
 151   /* Format the result.
 152    */
 153   tp = tmp;
 154   for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
 155   {
 156     /* Are we inside the best run of 0x00's?
 157      */
 158     if (best.base != -1 && i >= best.base && i < (best.base + best.len))
 159     {
 160       if (i == best.base)
 161          *tp++ = ':';
 162       continue;
 163     }
 164
 165     /* Are we following an initial run of 0x00s or any real hex?
 166      */
 167     if (i != 0)
 168        *tp++ = ':';
 169
 170     /* Is this address an encapsulated IPv4?
 171      */
 172     if (i == 6 && best.base == 0 &&
 173         (best.len == 6 || (best.len == 5 && words[5] == 0xffff)))
 174     {
 175       if (!inet_ntop_v4(src+12, tp, sizeof(tmp) - (tp - tmp)))
 176       {
 177         errno = ENOSPC;
 178         return (NULL);
 179       }
 180       tp += strlen(tp);
 181       break;
 182     }
 183     tp += sprintf (tp, "%lX", words[i]);
 184   }
 185
 186   /* Was it a trailing run of 0x00's?
 187    */
 188   if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
 189      *tp++ = ':';
 190   *tp++ = '\0';
 191
 192   /* Check for overflow, copy, and we're done.
 193    */
 194   if ((size_t)(tp - tmp) > size)
 195   {
 196     errno = ENOSPC;
 197     return (NULL);
 198   }
 199   return strcpy (dst, tmp);
 200   return (NULL);
 201 }
 202 #endif   /* INET6 */
 203
 204
 205 const char *
 206 inet_ntop(int af, const void *src, char *dst, size_t size)
 207 {
 208     switch (af) {
 209     case AF_INET :
 210         return inet_ntop_v4 (src, dst, size);
 211 #ifdef INET6
 212     case AF_INET6:
 213          return inet_ntop_v6 ((const u_char*)src, dst, size);
 214 #endif
 215     default :
 216         errno = EAFNOSUPPORT;
 217         return NULL;
 218     }
 219 }