resolv/inet_net_pton.c

   1 /*
   2  * Copyright (c) 1996,1999 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[] = "$BINDId: inet_net_pton.c,v 1.11 1999/01/08 19:23:44 vixie Exp $";
  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 (const char *src, u_char *dst,
  41                                     size_t size) __THROW;
  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 (int af, const char *src, void *dst, size_t size)
  58 {
  59         switch (af) {
  60         case AF_INET:
  61                 return (inet_net_pton_ipv4(src, dst, size));
  62         default:
  63                 __set_errno (EAFNOSUPPORT);
  64                 return (-1);
  65         }
  66 }
  67
  68 /*
  69  * static int
  70  * inet_net_pton_ipv4(src, dst, size)
  71  *      convert IPv4 network number from presentation to network format.
  72  *      accepts hex octets, hex strings, decimal octets, and /CIDR.
  73  *      "size" is in bytes and describes "dst".
  74  * return:
  75  *      number of bits, either imputed classfully or specified with /CIDR,
  76  *      or -1 if some failure occurred (check errno).  ENOENT means it was
  77  *      not an IPv4 network specification.
  78  * note:
  79  *      network byte order assumed.  this means 192.5.5.240/28 has
  80  *      0b11110000 in its fourth octet.
  81  * author:
  82  *      Paul Vixie (ISC), June 1996
  83  */
  84 static int
  85 inet_net_pton_ipv4 (const char *src, u_char *dst, size_t size)
  86 {
  87         static const char xdigits[] = "0123456789abcdef";
  88         int n, ch, tmp, dirty, bits;
  89         const u_char *odst = dst;
  90
  91         ch = *src++;
  92         if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
  93             && isascii(src[1]) && isxdigit(src[1])) {
  94                 /* Hexadecimal: Eat nybble string. */
  95                 if (size <= 0)
  96                         goto emsgsize;
  97                 dirty = 0;
  98                 tmp = 0;        /* To calm down gcc.  */
  99                 src++;  /* skip x or X. */
 100                 while (isxdigit((ch = *src++))) {
 101                         ch = _tolower(ch);
 102                         n = (const char *) __rawmemchr(xdigits, ch) - xdigits;
 103                         assert(n >= 0 && n <= 15);
 104                         if (dirty == 0)
 105                                 tmp = n;
 106                         else
 107                                 tmp = (tmp << 4) | n;
 108                         if (++dirty == 2) {
 109                                 if (size-- <= 0)
 110                                         goto emsgsize;
 111                                 *dst++ = (u_char) tmp;
 112                                 dirty = 0;
 113                         }
 114                 }
 115                 if (dirty) {  /* Odd trailing nybble? */
 116                         if (size-- <= 0)
 117                                 goto emsgsize;
 118                         *dst++ = (u_char) (tmp << 4);
 119                 }
 120         } else if (isascii(ch) && isdigit(ch)) {
 121                 /* Decimal: eat dotted digit string. */
 122                 for (;;) {
 123                         tmp = 0;
 124                         do {
 125                                 n = ((const char *) __rawmemchr(xdigits, ch)
 126                                      - xdigits);
 127                                 assert(n >= 0 && n <= 9);
 128                                 tmp *= 10;
 129                                 tmp += n;
 130                                 if (tmp > 255)
 131                                         goto enoent;
 132                         } while (isascii((ch = *src++)) && isdigit(ch));
 133                         if (size-- <= 0)
 134                                 goto emsgsize;
 135                         *dst++ = (u_char) tmp;
 136                         if (ch == '\0' || ch == '/')
 137                                 break;
 138                         if (ch != '.')
 139                                 goto enoent;
 140                         ch = *src++;
 141                         if (!isascii(ch) || !isdigit(ch))
 142                                 goto enoent;
 143                 }
 144         } else
 145                 goto enoent;
 146
 147         bits = -1;
 148         if (ch == '/' && isascii(src[0]) && isdigit(src[0]) && dst > odst) {
 149                 /* CIDR width specifier.  Nothing can follow it. */
 150                 ch = *src++;    /* Skip over the /. */
 151                 bits = 0;
 152                 do {
 153                         n = (const char *) __rawmemchr(xdigits, ch) - xdigits;
 154                         assert(n >= 0 && n <= 9);
 155                         bits *= 10;
 156                         bits += n;
 157                 } while (isascii((ch = *src++)) && isdigit(ch));
 158                 if (ch != '\0')
 159                         goto enoent;
 160                 if (bits > 32)
 161                         goto emsgsize;
 162         }
 163
 164         /* Firey death and destruction unless we prefetched EOS. */
 165         if (ch != '\0')
 166                 goto enoent;
 167
 168         /* If nothing was written to the destination, we found no address. */
 169         if (dst == odst)
 170                 goto enoent;
 171         /* If no CIDR spec was given, infer width from net class. */
 172         if (bits == -1) {
 173                 if (*odst >= 240)       /* Class E */
 174                         bits = 32;
 175                 else if (*odst >= 224)  /* Class D */
 176                         bits = 4;
 177                 else if (*odst >= 192)  /* Class C */
 178                         bits = 24;
 179                 else if (*odst >= 128)  /* Class B */
 180                         bits = 16;
 181                 else                    /* Class A */
 182                         bits = 8;
 183                 /* If imputed mask is narrower than specified octets, widen. */
 184                 if (bits >= 8 && bits < ((dst - odst) * 8))
 185                         bits = (dst - odst) * 8;
 186         }
 187         /* Extend network to cover the actual mask. */
 188         while (bits > ((dst - odst) * 8)) {
 189                 if (size-- <= 0)
 190                         goto emsgsize;
 191                 *dst++ = '\0';
 192         }
 193         return (bits);
 194
 195  enoent:
 196         __set_errno (ENOENT);
 197         return (-1);
 198
 199  emsgsize:
 200         __set_errno (EMSGSIZE);
 201         return (-1);
 202 }