lib/inet_pton.c

   1 /* inet_pton.c -- convert IPv4 and IPv6 addresses from text to binary form
   2
   3    Copyright (C) 2006, 2008-2024 Free Software Foundation, Inc.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file 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 <https://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 #if HAVE_DECL_INET_PTON
  41
  42 # undef inet_pton
  43
  44 int
  45 rpl_inet_pton (int af, const char *restrict src, void *restrict dst)
  46 {
  47   return inet_pton (af, src, dst);
  48 }
  49
  50 #else
  51
  52 # include <c-ctype.h>
  53 # include <string.h>
  54 # include <errno.h>
  55
  56 # define NS_INADDRSZ 4
  57 # define NS_IN6ADDRSZ 16
  58 # define NS_INT16SZ 2
  59
  60 /*
  61  * WARNING: Don't even consider trying to compile this on a system where
  62  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
  63  */
  64
  65 static int inet_pton4 (const char *src, unsigned char *dst);
  66 # if HAVE_IPV6
  67 static int inet_pton6 (const char *src, unsigned char *dst);
  68 # endif
  69
  70 /* int
  71  * inet_pton(af, src, dst)
  72  *      convert from presentation format (which usually means ASCII printable)
  73  *      to network format (which is usually some kind of binary format).
  74  * return:
  75  *      1 if the address was valid for the specified address family
  76  *      0 if the address wasn't valid ('dst' is untouched in this case)
  77  *      -1 if some other error occurred ('dst' is untouched in this case, too)
  78  * author:
  79  *      Paul Vixie, 1996.
  80  */
  81 int
  82 inet_pton (int af, const char *restrict src, void *restrict dst)
  83 {
  84   switch (af)
  85     {
  86     case AF_INET:
  87       return (inet_pton4 (src, dst));
  88
  89 # if HAVE_IPV6
  90     case AF_INET6:
  91       return (inet_pton6 (src, dst));
  92 # endif
  93
  94     default:
  95       errno = EAFNOSUPPORT;
  96       return (-1);
  97     }
  98   /* NOTREACHED */
  99 }
 100
 101 /* int
 102  * inet_pton4(src, dst)
 103  *      like inet_aton() but without all the hexadecimal, octal (with the
 104  *      exception of 0) and shorthand.
 105  * return:
 106  *      1 if 'src' is a valid dotted quad, else 0.
 107  * notice:
 108  *      does not touch 'dst' unless it's returning 1.
 109  * author:
 110  *      Paul Vixie, 1996.
 111  */
 112 static int
 113 inet_pton4 (const char *restrict src, unsigned char *restrict dst)
 114 {
 115   int saw_digit, octets, ch;
 116   unsigned char tmp[NS_INADDRSZ], *tp;
 117
 118   saw_digit = 0;
 119   octets = 0;
 120   *(tp = tmp) = 0;
 121   while ((ch = *src++) != '\0')
 122     {
 123
 124       if (ch >= '0' && ch <= '9')
 125         {
 126           unsigned new = *tp * 10 + (ch - '0');
 127
 128           if (saw_digit && *tp == 0)
 129             return (0);
 130           if (new > 255)
 131             return (0);
 132           *tp = new;
 133           if (!saw_digit)
 134             {
 135               if (++octets > 4)
 136                 return (0);
 137               saw_digit = 1;
 138             }
 139         }
 140       else if (ch == '.' && saw_digit)
 141         {
 142           if (octets == 4)
 143             return (0);
 144           *++tp = 0;
 145           saw_digit = 0;
 146         }
 147       else
 148         return (0);
 149     }
 150   if (octets < 4)
 151     return (0);
 152   memcpy (dst, tmp, NS_INADDRSZ);
 153   return (1);
 154 }
 155
 156 # if HAVE_IPV6
 157
 158 /* int
 159  * inet_pton6(src, dst)
 160  *      convert presentation level address to network order binary form.
 161  * return:
 162  *      1 if 'src' is a valid [RFC1884 2.2] address, else 0.
 163  * notice:
 164  *      (1) does not touch 'dst' unless it's returning 1.
 165  *      (2) :: in a full address is silently ignored.
 166  * credit:
 167  *      inspired by Mark Andrews.
 168  * author:
 169  *      Paul Vixie, 1996.
 170  */
 171 static int
 172 inet_pton6 (const char *restrict src, unsigned char *restrict dst)
 173 {
 174   static const char xdigits[] = "0123456789abcdef";
 175   unsigned char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
 176   const char *curtok;
 177   int ch, saw_xdigit;
 178   unsigned val;
 179
 180   tp = memset (tmp, '\0', NS_IN6ADDRSZ);
 181   endp = tp + NS_IN6ADDRSZ;
 182   colonp = NULL;
 183   /* Leading :: requires some special handling. */
 184   if (*src == ':')
 185     if (*++src != ':')
 186       return (0);
 187   curtok = src;
 188   saw_xdigit = 0;
 189   val = 0;
 190   while ((ch = c_tolower (*src++)) != '\0')
 191     {
 192       const char *pch;
 193
 194       pch = strchr (xdigits, ch);
 195       if (pch != NULL)
 196         {
 197           val <<= 4;
 198           val |= (pch - xdigits);
 199           if (val > 0xffff)
 200             return (0);
 201           saw_xdigit = 1;
 202           continue;
 203         }
 204       if (ch == ':')
 205         {
 206           curtok = src;
 207           if (!saw_xdigit)
 208             {
 209               if (colonp)
 210                 return (0);
 211               colonp = tp;
 212               continue;
 213             }
 214           else if (*src == '\0')
 215             {
 216               return (0);
 217             }
 218           if (tp + NS_INT16SZ > endp)
 219             return (0);
 220           *tp++ = (unsigned char) (val >> 8) & 0xff;
 221           *tp++ = (unsigned char) val & 0xff;
 222           saw_xdigit = 0;
 223           val = 0;
 224           continue;
 225         }
 226       if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
 227           inet_pton4 (curtok, tp) > 0)
 228         {
 229           tp += NS_INADDRSZ;
 230           saw_xdigit = 0;
 231           break;                /* '\0' was seen by inet_pton4(). */
 232         }
 233       return (0);
 234     }
 235   if (saw_xdigit)
 236     {
 237       if (tp + NS_INT16SZ > endp)
 238         return (0);
 239       *tp++ = (unsigned char) (val >> 8) & 0xff;
 240       *tp++ = (unsigned char) val & 0xff;
 241     }
 242   if (colonp != NULL)
 243     {
 244       /*
 245        * Since some memmove()'s erroneously fail to handle
 246        * overlapping regions, we'll do the shift by hand.
 247        */
 248       const int n = tp - colonp;
 249       int i;
 250
 251       if (tp == endp)
 252         return (0);
 253       for (i = 1; i <= n; i++)
 254         {
 255           endp[-i] = colonp[n - i];
 256           colonp[n - i] = 0;
 257         }
 258       tp = endp;
 259     }
 260   if (tp != endp)
 261     return (0);
 262   memcpy (dst, tmp, NS_IN6ADDRSZ);
 263   return (1);
 264 }
 265
 266 # endif
 267
 268 #endif