libkern/net/inet_aton.c

   1 /*-
   2  * Copyright (c) 2001 Charles Mott <cm@linktel.net>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26 #include <sys/param.h>
  27 #include <sys/systm.h>
  28
  29 #include <netinet/in.h>
  30
  31 /* XXX ctype.h is missing, see libkern/stdio/scanf.c */
  32 #if 1
  33 static inline int
  34 isspace(char c)
  35 {
  36         return c == ' ' || c == '\t' || c == '\n' || c == '\12';
  37 }
  38 #endif
  39
  40 int
  41 inet_aton(const char *cp, struct in_addr *addr)
  42 {
  43         u_long parts[4];
  44         in_addr_t val = 0;
  45         const char *c;
  46         char *endptr;
  47         int gotend, n;
  48
  49         c = (const char *)cp;
  50         n = 0;
  51
  52         /*
  53          * Run through the string, grabbing numbers until
  54          * the end of the string, or some error
  55          */
  56         gotend = 0;
  57         while (!gotend) {
  58                 unsigned long l;
  59
  60                 l = strtoul(c, &endptr, 0);
  61
  62                 if (l == ULONG_MAX || (l == 0 && endptr == c)) {
  63                         return 0;
  64                 }
  65
  66                 val = (in_addr_t)l;
  67
  68                 /*
  69                  * If the whole string is invalid, endptr will equal
  70                  * c.. this way we can make sure someone hasn't
  71                  * gone '.12' or something which would get past
  72                  * the next check.
  73                  */
  74                 if (endptr == c) {
  75                         return 0;
  76                 }
  77                 parts[n] = val;
  78                 c = endptr;
  79
  80                 /* Check the next character past the previous number's end */
  81                 switch (*c) {
  82                 case '.':
  83
  84                         /* Make sure we only do 3 dots .. */
  85                         if (n == 3) {   /* Whoops. Quit. */
  86                                 return 0;
  87                         }
  88                         n++;
  89                         c++;
  90                         break;
  91
  92                 case '\0':
  93                         gotend = 1;
  94                         break;
  95
  96                 default:
  97                         if (isspace((unsigned char)*c)) {
  98                                 gotend = 1;
  99                                 break;
 100                         } else {
 101                                 /* Invalid character, then fail. */
 102                                 return 0;
 103                         }
 104                 }
 105         }
 106
 107         /* Concoct the address according to the number of parts specified. */
 108         switch (n) {
 109         case 0:                         /* a -- 32 bits */
 110
 111                 /*
 112                  * Nothing is necessary here.  Overflow checking was
 113                  * already done in strtoul().
 114                  */
 115                 break;
 116         case 1:                         /* a.b -- 8.24 bits */
 117                 if (val > 0xffffff || parts[0] > 0xff) {
 118                         return 0;
 119                 }
 120                 val |= parts[0] << 24;
 121                 break;
 122
 123         case 2:                         /* a.b.c -- 8.8.16 bits */
 124                 if (val > 0xffff || parts[0] > 0xff || parts[1] > 0xff) {
 125                         return 0;
 126                 }
 127                 val |= (parts[0] << 24) | (parts[1] << 16);
 128                 break;
 129
 130         case 3:                         /* a.b.c.d -- 8.8.8.8 bits */
 131                 if (val > 0xff || parts[0] > 0xff || parts[1] > 0xff ||
 132                     parts[2] > 0xff) {
 133                         return 0;
 134                 }
 135                 val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
 136                 break;
 137         }
 138
 139         if (addr != NULL) {
 140                 addr->s_addr = htonl(val);
 141         }
 142         return 1;
 143 }