lib/ip/inet_addr.c

   1 /*
   2  * Copyright (c) 1983, 1990 Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted provided
   6  * that: (1) source distributions retain this entire copyright notice and
   7  * comment, and (2) distributions including binaries display the following
   8  * acknowledgement:  ``This product includes software developed by the
   9  * University of California, Berkeley and its contributors'' in the
  10  * documentation or other materials provided with the distribution and in
  11  * all advertising materials mentioning features or use of this software.
  12  * Neither the name of the University nor the names of its contributors may
  13  * be used to endorse or promote products derived from this software without
  14  * specific prior written permission.
  15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  16  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  17  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  */
  19
  20 #if defined(LIBC_SCCS) && !defined(lint)
  21 static char sccsid[] = "@(#)inet_addr.c 5.8 (Berkeley) 6/23/90";
  22 #endif /* LIBC_SCCS and not lint */
  23
  24 #if _MINIX
  25 #include <sys/types.h>
  26 #include <ctype.h>
  27 #include <errno.h>
  28
  29 #include <net/hton.h>
  30 #include <net/gen/in.h>
  31 #include <net/gen/inet.h>
  32 #endif
  33
  34 #ifdef __STDC__
  35 #define _CONST  const
  36 #else
  37 #define _CONST
  38 #endif
  39
  40 /*
  41  * Ascii internet address interpretation routine.
  42  * The value returned is in network order.
  43  */
  44 ipaddr_t
  45 inet_addr(cp)
  46         register _CONST char *cp;
  47 {
  48         ipaddr_t val;
  49
  50         if (inet_aton(cp, &val))
  51                 return (val);
  52         errno= EINVAL;
  53         return (ipaddr_t)-1;
  54 }
  55
  56 /*
  57  * Check whether "cp" is a valid ascii representation
  58  * of an Internet address and convert to a binary address.
  59  * Returns 1 if the address is valid, 0 if not.
  60  * This replaces inet_addr, the return value from which
  61  * cannot distinguish between failure and a local broadcast address.
  62  */
  63
  64 int
  65 inet_aton(cp, addr)
  66         register _CONST char *cp;
  67         ipaddr_t *addr;
  68 {
  69         register u32_t val, base, n;
  70         register char c;
  71         u32_t parts[4], *pp = parts;
  72
  73         for (;;) {
  74                 /*
  75                  * Collect number up to ``.''.
  76                  * Values are specified as for C:
  77                  * 0x=hex, 0=octal, other=decimal.
  78                  */
  79                 val = 0; base = 10;
  80                 if (*cp == '0') {
  81                         if (*++cp == 'x' || *cp == 'X')
  82                                 base = 16, cp++;
  83                         else
  84                                 base = 8;
  85                 }
  86                 while ((c = *cp) != '\0') {
  87                         if (isascii(c) && isdigit(c)) {
  88                                 val = (val * base) + (c - '0');
  89                                 cp++;
  90                                 continue;
  91                         }
  92                         if (base == 16 && isascii(c) && isxdigit(c)) {
  93                                 val = (val << 4) +
  94                                         (c + 10 - (islower(c) ? 'a' : 'A'));
  95                                 cp++;
  96                                 continue;
  97                         }
  98                         break;
  99                 }
 100                 if (*cp == '.') {
 101                         /*
 102                          * Internet format:
 103                          *      a.b.c.d
 104                          *      a.b.c   (with c treated as 16-bits)
 105                          *      a.b     (with b treated as 24 bits)
 106                          */
 107                         if (pp >= parts + 3 || val > 0xff)
 108                                 return (0);
 109                         *pp++ = val, cp++;
 110                 } else
 111                         break;
 112         }
 113         /*
 114          * Check for trailing characters.
 115          */
 116         if (*cp && (!isascii(*cp) || !isspace(*cp)))
 117                 return (0);
 118         /*
 119          * Concoct the address according to
 120          * the number of parts specified.
 121          */
 122         n = pp - parts + 1;
 123         switch (n) {
 124
 125         case 1:                         /* a -- 32 bits */
 126                 break;
 127
 128         case 2:                         /* a.b -- 8.24 bits */
 129                 if (val > 0xffffff)
 130                         return (0);
 131                 val |= parts[0] << 24;
 132                 break;
 133
 134         case 3:                         /* a.b.c -- 8.8.16 bits */
 135                 if (val > 0xffff)
 136                         return (0);
 137                 val |= (parts[0] << 24) | (parts[1] << 16);
 138                 break;
 139
 140         case 4:                         /* a.b.c.d -- 8.8.8.8 bits */
 141                 if (val > 0xff)
 142                         return (0);
 143                 val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
 144                 break;
 145         }
 146         if (addr)
 147                 *addr = htonl(val);
 148         return (1);
 149 }