external/bsd/tcpdump/dist/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 #ifdef HAVE_CONFIG_H
  40 #include "config.h"
  41 #endif
  42
  43 #include <tcpdump-stdinc.h>
  44
  45 #include <stdio.h>
  46
  47 /*
  48  *
  49  */
  50
  51 #ifndef IN6ADDRSZ
  52 #define IN6ADDRSZ   16   /* IPv6 T_AAAA */
  53 #endif
  54
  55 #ifndef INT16SZ
  56 #define INT16SZ     2    /* word size */
  57 #endif
  58
  59 static const char *
  60 inet_ntop_v4 (const void *src, char *dst, size_t size)
  61 {
  62     const char digits[] = "0123456789";
  63     int i;
  64     struct in_addr *addr = (struct in_addr *)src;
  65     u_long a = ntohl(addr->s_addr);
  66     const char *orig_dst = dst;
  67
  68     if (size < INET_ADDRSTRLEN) {
  69         errno = ENOSPC;
  70         return NULL;
  71     }
  72     for (i = 0; i < 4; ++i) {
  73         int n = (a >> (24 - i * 8)) & 0xFF;
  74         int non_zerop = 0;
  75
  76         if (non_zerop || n / 100 > 0) {
  77             *dst++ = digits[n / 100];
  78             n %= 100;
  79             non_zerop = 1;
  80         }
  81         if (non_zerop || n / 10 > 0) {
  82             *dst++ = digits[n / 10];
  83             n %= 10;
  84             non_zerop = 1;
  85         }
  86         *dst++ = digits[n];
  87         if (i != 3)
  88             *dst++ = '.';
  89     }
  90     *dst++ = '\0';
  91     return orig_dst;
  92 }
  93
  94 #ifdef INET6
  95 /*
  96  * Convert IPv6 binary address into presentation (printable) format.
  97  */
  98 static const char *
  99 inet_ntop_v6 (const u_char *src, char *dst, size_t size)
 100 {
 101   /*
 102    * Note that int32_t and int16_t need only be "at least" large enough
 103    * to contain a value of the specified size.  On some systems, like
 104    * Crays, there is no such thing as an integer variable with 16 bits.
 105    * Keep this in mind if you think this function should have been coded
 106    * to use pointer overlays.  All the world's not a VAX.
 107    */
 108   char  tmp [INET6_ADDRSTRLEN+1];
 109   char *tp;
 110   struct {
 111     long base;
 112     long len;
 113   } best, cur;
 114   u_long words [IN6ADDRSZ / INT16SZ];
 115   int    i;
 116
 117   /* Preprocess:
 118    *  Copy the input (bytewise) array into a wordwise array.
 119    *  Find the longest run of 0x00's in src[] for :: shorthanding.
 120    */
 121   memset (words, 0, sizeof(words));
 122   for (i = 0; i < IN6ADDRSZ; i++)
 123       words[i/2] |= (src[i] << ((1 - (i % 2)) << 3));
 124
 125   best.len = 0;
 126   best.base = -1;
 127   cur.len = 0;
 128   cur.base  = -1;
 129   for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
 130   {
 131     if (words[i] == 0)
 132     {
 133       if (cur.base == -1)
 134            cur.base = i, cur.len = 1;
 135       else cur.len++;
 136     }
 137     else if (cur.base != -1)
 138     {
 139       if (best.base == -1 || cur.len > best.len)
 140          best = cur;
 141       cur.base = -1;
 142     }
 143   }
 144   if ((cur.base != -1) && (best.base == -1 || cur.len > best.len))
 145      best = cur;
 146   if (best.base != -1 && best.len < 2)
 147      best.base = -1;
 148
 149   /* Format the result.
 150    */
 151   tp = tmp;
 152   for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
 153   {
 154     /* Are we inside the best run of 0x00's?
 155      */
 156     if (best.base != -1 && i >= best.base && i < (best.base + best.len))
 157     {
 158       if (i == best.base)
 159          *tp++ = ':';
 160       continue;
 161     }
 162
 163     /* Are we following an initial run of 0x00s or any real hex?
 164      */
 165     if (i != 0)
 166        *tp++ = ':';
 167
 168     /* Is this address an encapsulated IPv4?
 169      */
 170     if (i == 6 && best.base == 0 &&
 171         (best.len == 6 || (best.len == 5 && words[5] == 0xffff)))
 172     {
 173       if (!inet_ntop_v4(src+12, tp, sizeof(tmp) - (tp - tmp)))
 174       {
 175         errno = ENOSPC;
 176         return (NULL);
 177       }
 178       tp += strlen(tp);
 179       break;
 180     }
 181     tp += sprintf (tp, "%lx", words[i]);
 182   }
 183
 184   /* Was it a trailing run of 0x00's?
 185    */
 186   if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
 187      *tp++ = ':';
 188   *tp++ = '\0';
 189
 190   /* Check for overflow, copy, and we're done.
 191    */
 192   if ((size_t)(tp - tmp) > size)
 193   {
 194     errno = ENOSPC;
 195     return (NULL);
 196   }
 197   return strcpy (dst, tmp);
 198 }
 199 #endif   /* INET6 */
 200
 201
 202 const char *
 203 inet_ntop(int af, const void *src, char *dst, size_t size)
 204 {
 205     switch (af) {
 206     case AF_INET :
 207         return inet_ntop_v4 (src, dst, size);
 208 #ifdef INET6
 209     case AF_INET6:
 210          return inet_ntop_v6 ((const u_char*)src, dst, size);
 211 #endif
 212     default :
 213         errno = EAFNOSUPPORT;
 214         return NULL;
 215     }
 216 }