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                 src++;  /* skip x or X. */
 106                 while ((ch = *src++) != '\0' &&
 107                        isascii(ch) && isxdigit(ch)) {
 108                         ch = _tolower(ch);
 109                         n = strchr(xdigits, ch) - xdigits;
 110                         assert(n >= 0 && n <= 15);
 111                         *dst |= n;
 112                         if (!dirty++)
 113                                 *dst <<= 4;
 114                         else if (size-- > 0)
 115                                 *++dst = 0, dirty = 0;
 116                         else
 117                                 goto emsgsize;
 118                 }
 119                 if (dirty)
 120                         size--;
 121         } else if (isascii(ch) && isdigit(ch)) {
 122                 /* Decimal: eat dotted digit string. */
 123                 for (;;) {
 124                         tmp = 0;
 125                         do {
 126                                 n = strchr(xdigits, ch) - xdigits;
 127                                 assert(n >= 0 && n <= 9);
 128                                 tmp *= 10;
 129                                 tmp += n;
 130                                 if (tmp > 255)
 131                                         goto enoent;
 132                         } while ((ch = *src++) != '\0' &&
 133                                  isascii(ch) && isdigit(ch));
 134                         if (size-- <= 0)
 135                                 goto emsgsize;
 136                         *dst++ = (u_char) tmp;
 137                         if (ch == '\0' || ch == '/')
 138                                 break;
 139                         if (ch != '.')
 140                                 goto enoent;
 141                         ch = *src++;
 142                         if (!isascii(ch) || !isdigit(ch))
 143                                 goto enoent;
 144                 }
 145         } else
 146                 goto enoent;
 147
 148         bits = -1;
 149         if (ch == '/' && isascii(src[0]) && isdigit(src[0]) && dst > odst) {
 150                 /* CIDR width specifier.  Nothing can follow it. */
 151                 ch = *src++;    /* Skip over the /. */
 152                 bits = 0;
 153                 do {
 154                         n = strchr(xdigits, ch) - xdigits;
 155                         assert(n >= 0 && n <= 9);
 156                         bits *= 10;
 157                         bits += n;
 158                 } while ((ch = *src++) != '\0' &&
 159                          isascii(ch) && isdigit(ch));
 160                 if (ch != '\0')
 161                         goto enoent;
 162                 if (bits > 32)
 163                         goto emsgsize;
 164         }
 165
 166         /* Firey death and destruction unless we prefetched EOS. */
 167         if (ch != '\0')
 168                 goto enoent;
 169
 170         /* If nothing was written to the destination, we found no address. */
 171         if (dst == odst)
 172                 goto enoent;
 173         /* If no CIDR spec was given, infer width from net class. */
 174         if (bits == -1) {
 175                 if (*odst >= 240)       /* Class E */
 176                         bits = 32;
 177                 else if (*odst >= 224)  /* Class D */
 178                         bits = 4;
 179                 else if (*odst >= 192)  /* Class C */
 180                         bits = 24;
 181                 else if (*odst >= 128)  /* Class B */
 182                         bits = 16;
 183                 else                    /* Class A */
 184                         bits = 8;
 185                 /* If imputed mask is narrower than specified octets, widen. */
 186                 if (bits >= 8 && bits < ((dst - odst) * 8))
 187                         bits = (dst - odst) * 8;
 188         }
 189         /* Extend network to cover the actual mask. */
 190         while (bits > ((dst - odst) * 8)) {
 191                 if (size-- <= 0)
 192                         goto emsgsize;
 193                 *dst++ = '\0';
 194         }
 195         return (bits);
 196
 197  enoent:
 198         __set_errno (ENOENT);
 199         return (-1);
 200
 201  emsgsize:
 202         __set_errno (EMSGSIZE);
 203         return (-1);
 204 }