lib/inet_pton.c

   1 /* inet_pton.c -- convert IPv4 and IPv6 addresses from text to binary form
   2
   3    Copyright (C) 2006, 2008, 2009, 2010 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 /*
  19  * Copyright (c) 1996,1999 by Internet Software Consortium.
  20  *
  21  * Permission to use, copy, modify, and distribute this software for any
  22  * purpose with or without fee is hereby granted, provided that the above
  23  * copyright notice and this permission notice appear in all copies.
  24  *
  25  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  26  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  28  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  29  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  30  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  31  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  32  * SOFTWARE.
  33  */
  34
  35 #include <config.h>
  36
  37 /* Specification.  */
  38 #include <arpa/inet.h>
  39
  40 #include <c-ctype.h>
  41 #include <string.h>
  42 #include <errno.h>
  43
  44 #define NS_INADDRSZ 4
  45 #define NS_IN6ADDRSZ 16
  46 #define NS_INT16SZ 2
  47
  48 /*
  49  * WARNING: Don't even consider trying to compile this on a system where
  50  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  51  */
  52
  53 static int inet_pton4 (const char *src, unsigned char *dst);
  54 #if HAVE_IPV6
  55 static int inet_pton6 (const char *src, unsigned char *dst);
  56 #endif
  57
  58 /* int
  59  * inet_pton(af, src, dst)
  60  *      convert from presentation format (which usually means ASCII printable)
  61  *      to network format (which is usually some kind of binary format).
  62  * return:
  63  *      1 if the address was valid for the specified address family
  64  *      0 if the address wasn't valid (`dst' is untouched in this case)
  65  *      -1 if some other error occurred (`dst' is untouched in this case, too)
  66  * author:
  67  *      Paul Vixie, 1996.
  68  */
  69 int
  70 inet_pton (int af, const char *restrict src, void *restrict dst)
  71 {
  72   switch (af)
  73     {
  74     case AF_INET:
  75       return (inet_pton4 (src, dst));
  76
  77 #if HAVE_IPV6
  78     case AF_INET6:
  79       return (inet_pton6 (src, dst));
  80 #endif
  81
  82     default:
  83       errno = EAFNOSUPPORT;
  84       return (-1);
  85     }
  86   /* NOTREACHED */
  87 }
  88
  89 /* int
  90  * inet_pton4(src, dst)
  91  *      like inet_aton() but without all the hexadecimal, octal (with the
  92  *      exception of 0) and shorthand.
  93  * return:
  94  *      1 if `src' is a valid dotted quad, else 0.
  95  * notice:
  96  *      does not touch `dst' unless it's returning 1.
  97  * author:
  98  *      Paul Vixie, 1996.
  99  */
 100 static int
 101 inet_pton4 (const char *restrict src, unsigned char *restrict dst)
 102 {
 103   int saw_digit, octets, ch;
 104   unsigned char tmp[NS_INADDRSZ], *tp;
 105
 106   saw_digit = 0;
 107   octets = 0;
 108   *(tp = tmp) = 0;
 109   while ((ch = *src++) != '\0')
 110     {
 111
 112       if (ch >= '0' && ch <= '9')
 113         {
 114           unsigned new = *tp * 10 + (ch - '0');
 115
 116           if (saw_digit && *tp == 0)
 117             return (0);
 118           if (new > 255)
 119             return (0);
 120           *tp = new;
 121           if (!saw_digit)
 122             {
 123               if (++octets > 4)
 124                 return (0);
 125               saw_digit = 1;
 126             }
 127         }
 128       else if (ch == '.' && saw_digit)
 129         {
 130           if (octets == 4)
 131             return (0);
 132           *++tp = 0;
 133           saw_digit = 0;
 134         }
 135       else
 136         return (0);
 137     }
 138   if (octets < 4)
 139     return (0);
 140   memcpy (dst, tmp, NS_INADDRSZ);
 141   return (1);
 142 }
 143
 144 #if HAVE_IPV6
 145
 146 /* int
 147  * inet_pton6(src, dst)
 148  *      convert presentation level address to network order binary form.
 149  * return:
 150  *      1 if `src' is a valid [RFC1884 2.2] address, else 0.
 151  * notice:
 152  *      (1) does not touch `dst' unless it's returning 1.
 153  *      (2) :: in a full address is silently ignored.
 154  * credit:
 155  *      inspired by Mark Andrews.
 156  * author:
 157  *      Paul Vixie, 1996.
 158  */
 159 static int
 160 inet_pton6 (const char *restrict src, unsigned char *restrict dst)
 161 {
 162   static const char xdigits[] = "0123456789abcdef";
 163   unsigned char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
 164   const char *curtok;
 165   int ch, saw_xdigit;
 166   unsigned val;
 167
 168   tp = memset (tmp, '\0', NS_IN6ADDRSZ);
 169   endp = tp + NS_IN6ADDRSZ;
 170   colonp = NULL;
 171   /* Leading :: requires some special handling. */
 172   if (*src == ':')
 173     if (*++src != ':')
 174       return (0);
 175   curtok = src;
 176   saw_xdigit = 0;
 177   val = 0;
 178   while ((ch = c_tolower (*src++)) != '\0')
 179     {
 180       const char *pch;
 181
 182       pch = strchr (xdigits, ch);
 183       if (pch != NULL)
 184         {
 185           val <<= 4;
 186           val |= (pch - xdigits);
 187           if (val > 0xffff)
 188             return (0);
 189           saw_xdigit = 1;
 190           continue;
 191         }
 192       if (ch == ':')
 193         {
 194           curtok = src;
 195           if (!saw_xdigit)
 196             {
 197               if (colonp)
 198                 return (0);
 199               colonp = tp;
 200               continue;
 201             }
 202           else if (*src == '\0')
 203             {
 204               return (0);
 205             }
 206           if (tp + NS_INT16SZ > endp)
 207             return (0);
 208           *tp++ = (u_char) (val >> 8) & 0xff;
 209           *tp++ = (u_char) val & 0xff;
 210           saw_xdigit = 0;
 211           val = 0;
 212           continue;
 213         }
 214       if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
 215           inet_pton4 (curtok, tp) > 0)
 216         {
 217           tp += NS_INADDRSZ;
 218           saw_xdigit = 0;
 219           break;                /* '\0' was seen by inet_pton4(). */
 220         }
 221       return (0);
 222     }
 223   if (saw_xdigit)
 224     {
 225       if (tp + NS_INT16SZ > endp)
 226         return (0);
 227       *tp++ = (u_char) (val >> 8) & 0xff;
 228       *tp++ = (u_char) val & 0xff;
 229     }
 230   if (colonp != NULL)
 231     {
 232       /*
 233        * Since some memmove()'s erroneously fail to handle
 234        * overlapping regions, we'll do the shift by hand.
 235        */
 236       const int n = tp - colonp;
 237       int i;
 238
 239       if (tp == endp)
 240         return (0);
 241       for (i = 1; i <= n; i++)
 242         {
 243           endp[-i] = colonp[n - i];
 244           colonp[n - i] = 0;
 245         }
 246       tp = endp;
 247     }
 248   if (tp != endp)
 249     return (0);
 250   memcpy (dst, tmp, NS_IN6ADDRSZ);
 251   return (1);
 252 }
 253 #endif