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
  95                 xdigits[] = "0123456789abcdef",
  96                 digits[] = "0123456789";
  97         int n, ch, tmp, dirty, bits;
  98         const u_char *odst = dst;
  99
 100         ch = *src++;
 101         if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
 102             && isascii(src[1]) && isxdigit(src[1])) {
 103                 /* Hexadecimal: Eat nybble string. */
 104                 if (size <= 0)
 105                         goto emsgsize;
 106                 *dst = 0, dirty = 0;
 107                 src++;  /* skip x or X. */
 108                 while ((ch = *src++) != '\0' &&
 109                        isascii(ch) && isxdigit(ch)) {
 110                         ch = _tolower(ch);
 111                         n = strchr(xdigits, ch) - xdigits;
 112                         assert(n >= 0 && n <= 15);
 113                         *dst |= n;
 114                         if (!dirty++)
 115                                 *dst <<= 4;
 116                         else if (size-- > 0)
 117                                 *++dst = 0, dirty = 0;
 118                         else
 119                                 goto emsgsize;
 120                 }
 121                 if (dirty)
 122                         size--;
 123         } else if (isascii(ch) && isdigit(ch)) {
 124                 /* Decimal: eat dotted digit string. */
 125                 for (;;) {
 126                         tmp = 0;
 127                         do {
 128                                 n = strchr(digits, ch) - digits;
 129                                 assert(n >= 0 && n <= 9);
 130                                 tmp *= 10;
 131                                 tmp += n;
 132                                 if (tmp > 255)
 133                                         goto enoent;
 134                         } while ((ch = *src++) != '\0' &&
 135                                  isascii(ch) && isdigit(ch));
 136                         if (size-- <= 0)
 137                                 goto emsgsize;
 138                         *dst++ = (u_char) tmp;
 139                         if (ch == '\0' || ch == '/')
 140                                 break;
 141                         if (ch != '.')
 142                                 goto enoent;
 143                         ch = *src++;
 144                         if (!isascii(ch) || !isdigit(ch))
 145                                 goto enoent;
 146                 }
 147         } else
 148                 goto enoent;
 149
 150         bits = -1;
 151         if (ch == '/' && isascii(src[0]) && isdigit(src[0]) && dst > odst) {
 152                 /* CIDR width specifier.  Nothing can follow it. */
 153                 ch = *src++;    /* Skip over the /. */
 154                 bits = 0;
 155                 do {
 156                         n = strchr(digits, ch) - digits;
 157                         assert(n >= 0 && n <= 9);
 158                         bits *= 10;
 159                         bits += n;
 160                 } while ((ch = *src++) != '\0' &&
 161                          isascii(ch) && isdigit(ch));
 162                 if (ch != '\0')
 163                         goto enoent;
 164                 if (bits > 32)
 165                         goto emsgsize;
 166         }
 167
 168         /* Firey death and destruction unless we prefetched EOS. */
 169         if (ch != '\0')
 170                 goto enoent;
 171
 172         /* If nothing was written to the destination, we found no address. */
 173         if (dst == odst)
 174                 goto enoent;
 175         /* If no CIDR spec was given, infer width from net class. */
 176         if (bits == -1) {
 177                 if (*odst >= 240)       /* Class E */
 178                         bits = 32;
 179                 else if (*odst >= 224)  /* Class D */
 180                         bits = 4;
 181                 else if (*odst >= 192)  /* Class C */
 182                         bits = 24;
 183                 else if (*odst >= 128)  /* Class B */
 184                         bits = 16;
 185                 else                    /* Class A */
 186                         bits = 8;
 187                 /* If imputed mask is narrower than specified octets, widen. */
 188                 if (bits >= 8 && bits < ((dst - odst) * 8))
 189                         bits = (dst - odst) * 8;
 190         }
 191         /* Extend network to cover the actual mask. */
 192         while (bits > ((dst - odst) * 8)) {
 193                 if (size-- <= 0)
 194                         goto emsgsize;
 195                 *dst++ = '\0';
 196         }
 197         return (bits);
 198
 199  enoent:
 200         __set_errno (ENOENT);
 201         return (-1);
 202
 203  emsgsize:
 204         __set_errno (EMSGSIZE);
 205         return (-1);
 206 }