resolv/inet_net_pton.c

   1 /*
   2  * Copyright (c) 1996 by Internet Software Consortium.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  */
  17
  18 #if defined(LIBC_SCCS) && !defined(lint)
  19 static const char rcsid[] = "$Id$";
  20 #endif
  21
  22 #include <sys/types.h>
  23 #include <sys/socket.h>
  24 #include <netinet/in.h>
  25 #include <arpa/inet.h>
  26
  27 #include <assert.h>
  28 #include <ctype.h>
  29 #include <errno.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <stdlib.h>
  33
  34 #ifdef SPRINTF_CHAR
  35 # define SPRINTF(x) strlen(sprintf/**/x)
  36 #else
  37 # define SPRINTF(x) ((size_t)sprintf x)
  38 #endif
  39
  40 static int      inet_net_pton_ipv4 __P((const char *src, u_char *dst,
  41                                         size_t size));
  42
  43 /*
  44  * static int
  45  * inet_net_pton(af, src, dst, size)
  46  *      convert network number from presentation to network format.
  47  *      accepts hex octets, hex strings, decimal octets, and /CIDR.
  48  *      "size" is in bytes and describes "dst".
  49  * return:
  50  *      number of bits, either imputed classfully or specified with /CIDR,
  51  *      or -1 if some failure occurred (check errno).  ENOENT means it was
  52  *      not a valid network specification.
  53  * author:
  54  *      Paul Vixie (ISC), June 1996
  55  */
  56 int
  57 inet_net_pton(af, src, dst, size)
  58         int af;
  59         const char *src;
  60         void *dst;
  61         size_t size;
  62 {
  63         switch (af) {
  64         case AF_INET:
  65                 return (inet_net_pton_ipv4(src, dst, size));
  66         default:
  67                 __set_errno (EAFNOSUPPORT);
  68                 return (-1);
  69         }
  70 }
  71
  72 /*
  73  * static int
  74  * inet_net_pton_ipv4(src, dst, size)
  75  *      convert IPv4 network number from presentation to network format.
  76  *      accepts hex octets, hex strings, decimal octets, and /CIDR.
  77  *      "size" is in bytes and describes "dst".
  78  * return:
  79  *      number of bits, either imputed classfully or specified with /CIDR,
  80  *      or -1 if some failure occurred (check errno).  ENOENT means it was
  81  *      not an IPv4 network specification.
  82  * note:
  83  *      network byte order assumed.  this means 192.5.5.240/28 has
  84  *      0x11110000 in its fourth octet.
  85  * author:
  86  *      Paul Vixie (ISC), June 1996
  87  */
  88 static int
  89 inet_net_pton_ipv4(src, dst, size)
  90         const char *src;
  91         u_char *dst;
  92         size_t size;
  93 {
  94         static const char xdigits[] = "0123456789abcdef";
  95         int n, ch, tmp, dirty, bits;
  96         const u_char *odst = dst;
  97
  98         ch = *src++;
  99         if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
 100             && isascii(src[1]) && isxdigit(src[1])) {
 101                 /* Hexadecimal: Eat nybble string. */
 102                 if (size <= 0)
 103                         goto emsgsize;
 104                 *dst = 0, dirty = 0;
 105                 tmp = 0;        /* To calm down gcc.  */
 106                 src++;  /* skip x or X. */
 107                 while (isxdigit((ch = *src++))) {
 108                         ch = _tolower(ch);
 109                         n = (const char *) __rawmemchr(xdigits, ch) - xdigits;
 110                         assert(n >= 0 && n <= 15);
 111                         if (dirty == 0)
 112                                 tmp = n << 4;
 113                         else
 114                                 tmp |= n;
 115                         if (++dirty == 2) {
 116                                 if (size-- <= 0)
 117                                         goto emsgsize;
 118                                 *dst++ = (u_char) tmp;
 119                                 dirty = 0;
 120                         }
 121                 }
 122                 if (dirty) {
 123                         if (size-- <= 0)
 124                                 goto emsgsize;
 125                         *dst = (u_char) tmp;
 126                 }
 127         } else if (isascii(ch) && isdigit(ch)) {
 128                 /* Decimal: eat dotted digit string. */
 129                 for (;;) {
 130                         tmp = 0;
 131                         do {
 132                                 n = ((const char *) __rawmemchr(xdigits, ch)
 133                                      - xdigits);
 134                                 assert(n >= 0 && n <= 9);
 135                                 tmp *= 10;
 136                                 tmp += n;
 137                                 if (tmp > 255)
 138                                         goto enoent;
 139                         } while (isascii((ch = *src++)) && isdigit(ch));
 140                         if (size-- <= 0)
 141                                 goto emsgsize;
 142                         *dst++ = (u_char) tmp;
 143                         if (ch == '\0' || ch == '/')
 144                                 break;
 145                         if (ch != '.')
 146                                 goto enoent;
 147                         ch = *src++;
 148                         if (!isascii(ch) || !isdigit(ch))
 149                                 goto enoent;
 150                 }
 151         } else
 152                 goto enoent;
 153
 154         bits = -1;
 155         if (ch == '/' && isascii(src[0]) && isdigit(src[0]) && dst > odst) {
 156                 /* CIDR width specifier.  Nothing can follow it. */
 157                 ch = *src++;    /* Skip over the /. */
 158                 bits = 0;
 159                 do {
 160                         n = (const char *) __rawmemchr(xdigits, ch) - xdigits;
 161                         assert(n >= 0 && n <= 9);
 162                         bits *= 10;
 163                         bits += n;
 164                 } while (isascii((ch = *src++)) && isdigit(ch));
 165                 if (ch != '\0')
 166                         goto enoent;
 167                 if (bits > 32)
 168                         goto emsgsize;
 169         }
 170
 171         /* Firey death and destruction unless we prefetched EOS. */
 172         if (ch != '\0')
 173                 goto enoent;
 174
 175         /* If nothing was written to the destination, we found no address. */
 176         if (dst == odst)
 177                 goto enoent;
 178         /* If no CIDR spec was given, infer width from net class. */
 179         if (bits == -1) {
 180                 if (*odst >= 240)       /* Class E */
 181                         bits = 32;
 182                 else if (*odst >= 224)  /* Class D */
 183                         bits = 4;
 184                 else if (*odst >= 192)  /* Class C */
 185                         bits = 24;
 186                 else if (*odst >= 128)  /* Class B */
 187                         bits = 16;
 188                 else                    /* Class A */
 189                         bits = 8;
 190                 /* If imputed mask is narrower than specified octets, widen. */
 191                 if (bits >= 8 && bits < ((dst - odst) * 8))
 192                         bits = (dst - odst) * 8;
 193         }
 194         /* Extend network to cover the actual mask. */
 195         while (bits > ((dst - odst) * 8)) {
 196                 if (size-- <= 0)
 197                         goto emsgsize;
 198                 *dst++ = '\0';
 199         }
 200         return (bits);
 201
 202  enoent:
 203         __set_errno (ENOENT);
 204         return (-1);
 205
 206  emsgsize:
 207         __set_errno (EMSGSIZE);
 208         return (-1);
 209 }