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 #include <sys/types.h>
  19 #include <sys/socket.h>
  20 #include <netinet/in.h>
  21 #include <arpa/inet.h>
  22
  23 #include <assert.h>
  24 #include <ctype.h>
  25 #include <errno.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <stdlib.h>
  29
  30 #ifdef SPRINTF_CHAR
  31 # define SPRINTF(x) strlen(sprintf/**/x)
  32 #else
  33 # define SPRINTF(x) ((size_t)sprintf x)
  34 #endif
  35
  36 static int      inet_net_pton_ipv4 (const char *src, u_char *dst,
  37                                     size_t size) __THROW;
  38
  39 /*
  40  * static int
  41  * inet_net_pton(af, src, dst, size)
  42  *      convert network number from presentation to network format.
  43  *      accepts hex octets, hex strings, decimal octets, and /CIDR.
  44  *      "size" is in bytes and describes "dst".
  45  * return:
  46  *      number of bits, either imputed classfully or specified with /CIDR,
  47  *      or -1 if some failure occurred (check errno).  ENOENT means it was
  48  *      not a valid network specification.
  49  * author:
  50  *      Paul Vixie (ISC), June 1996
  51  */
  52 int
  53 inet_net_pton (int af, const char *src, void *dst, size_t size)
  54 {
  55         switch (af) {
  56         case AF_INET:
  57                 return (inet_net_pton_ipv4(src, dst, size));
  58         default:
  59                 __set_errno (EAFNOSUPPORT);
  60                 return (-1);
  61         }
  62 }
  63
  64 /*
  65  * static int
  66  * inet_net_pton_ipv4(src, dst, size)
  67  *      convert IPv4 network number from presentation to network format.
  68  *      accepts hex octets, hex strings, decimal octets, and /CIDR.
  69  *      "size" is in bytes and describes "dst".
  70  * return:
  71  *      number of bits, either imputed classfully or specified with /CIDR,
  72  *      or -1 if some failure occurred (check errno).  ENOENT means it was
  73  *      not an IPv4 network specification.
  74  * note:
  75  *      network byte order assumed.  this means 192.5.5.240/28 has
  76  *      0b11110000 in its fourth octet.
  77  * author:
  78  *      Paul Vixie (ISC), June 1996
  79  */
  80 static int
  81 inet_net_pton_ipv4 (const char *src, u_char *dst, size_t size)
  82 {
  83         static const char xdigits[] = "0123456789abcdef";
  84         int n, ch, tmp, dirty, bits;
  85         const u_char *odst = dst;
  86
  87         ch = *src++;
  88         if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
  89             && isascii(src[1]) && isxdigit(src[1])) {
  90                 /* Hexadecimal: Eat nybble string. */
  91                 if (size <= 0)
  92                         goto emsgsize;
  93                 dirty = 0;
  94                 tmp = 0;        /* To calm down gcc.  */
  95                 src++;  /* skip x or X. */
  96                 while (isxdigit((ch = *src++))) {
  97                         ch = _tolower(ch);
  98                         n = (const char *) __rawmemchr(xdigits, ch) - xdigits;
  99                         assert(n >= 0 && n <= 15);
 100                         if (dirty == 0)
 101                                 tmp = n;
 102                         else
 103                                 tmp = (tmp << 4) | n;
 104                         if (++dirty == 2) {
 105                                 if (size-- <= 0)
 106                                         goto emsgsize;
 107                                 *dst++ = (u_char) tmp;
 108                                 dirty = 0;
 109                         }
 110                 }
 111                 if (dirty) {  /* Odd trailing nybble? */
 112                         if (size-- <= 0)
 113                                 goto emsgsize;
 114                         *dst++ = (u_char) (tmp << 4);
 115                 }
 116         } else if (isascii(ch) && isdigit(ch)) {
 117                 /* Decimal: eat dotted digit string. */
 118                 for (;;) {
 119                         tmp = 0;
 120                         do {
 121                                 n = ((const char *) __rawmemchr(xdigits, ch)
 122                                      - xdigits);
 123                                 assert(n >= 0 && n <= 9);
 124                                 tmp *= 10;
 125                                 tmp += n;
 126                                 if (tmp > 255)
 127                                         goto enoent;
 128                         } while (isascii((ch = *src++)) && isdigit(ch));
 129                         if (size-- <= 0)
 130                                 goto emsgsize;
 131                         *dst++ = (u_char) tmp;
 132                         if (ch == '\0' || ch == '/')
 133                                 break;
 134                         if (ch != '.')
 135                                 goto enoent;
 136                         ch = *src++;
 137                         if (!isascii(ch) || !isdigit(ch))
 138                                 goto enoent;
 139                 }
 140         } else
 141                 goto enoent;
 142
 143         bits = -1;
 144         if (ch == '/' && isascii(src[0]) && isdigit(src[0]) && dst > odst) {
 145                 /* CIDR width specifier.  Nothing can follow it. */
 146                 ch = *src++;    /* Skip over the /. */
 147                 bits = 0;
 148                 do {
 149                         n = (const char *) __rawmemchr(xdigits, ch) - xdigits;
 150                         assert(n >= 0 && n <= 9);
 151                         bits *= 10;
 152                         bits += n;
 153                 } while (isascii((ch = *src++)) && isdigit(ch));
 154                 if (ch != '\0')
 155                         goto enoent;
 156                 if (bits > 32)
 157                         goto emsgsize;
 158         }
 159
 160         /* Fiery death and destruction unless we prefetched EOS. */
 161         if (ch != '\0')
 162                 goto enoent;
 163
 164         /* If nothing was written to the destination, we found no address. */
 165         if (dst == odst)
 166                 goto enoent;
 167         /* If no CIDR spec was given, infer width from net class. */
 168         if (bits == -1) {
 169                 if (*odst >= 240)       /* Class E */
 170                         bits = 32;
 171                 else if (*odst >= 224)  /* Class D */
 172                         bits = 4;
 173                 else if (*odst >= 192)  /* Class C */
 174                         bits = 24;
 175                 else if (*odst >= 128)  /* Class B */
 176                         bits = 16;
 177                 else                    /* Class A */
 178                         bits = 8;
 179                 /* If imputed mask is narrower than specified octets, widen. */
 180                 if (bits >= 8 && bits < ((dst - odst) * 8))
 181                         bits = (dst - odst) * 8;
 182         }
 183         /* Extend network to cover the actual mask. */
 184         while (bits > ((dst - odst) * 8)) {
 185                 if (size-- <= 0)
 186                         goto emsgsize;
 187                 *dst++ = '\0';
 188         }
 189         return (bits);
 190
 191  enoent:
 192         __set_errno (ENOENT);
 193         return (-1);
 194
 195  emsgsize:
 196         __set_errno (EMSGSIZE);
 197         return (-1);
 198 }