FreeBSD/Linux Kernel Cross Reference
sys/libkern/net/inet_aton.c

     /*-
      * Copyright (c) 2001 Charles Mott <cm@linktel.net>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    #include <sys/param.h>
    #include <sys/systm.h>
    
    #include <netinet/in.h>
    
    /* XXX ctype.h is missing, see libkern/stdio/scanf.c */
    #if 1
    static inline int
    isspace(char c)
    {
            return c == ' ' || c == '\t' || c == '\n' || c == '\12';
    }
    #endif
    
    int
    inet_aton(const char *cp, struct in_addr *addr)
    {
            u_long parts[4];
            in_addr_t val = 0;
            const char *c;
            char *endptr;
            int gotend, n;
    
            c = (const char *)cp;
            n = 0;
    
            /*
             * Run through the string, grabbing numbers until
             * the end of the string, or some error
             */
            gotend = 0;
            while (!gotend) {
                    unsigned long l;
    
                    l = strtoul(c, &endptr, 0);
    
                    if (l == ULONG_MAX || (l == 0 && endptr == c)) {
                            return 0;
                    }
    
                    val = (in_addr_t)l;
    
                    /*
                     * If the whole string is invalid, endptr will equal
                     * c.. this way we can make sure someone hasn't
                     * gone '.12' or something which would get past
                     * the next check.
                     */
                    if (endptr == c) {
                            return 0;
                    }
                    parts[n] = val;
                    c = endptr;
    
                    /* Check the next character past the previous number's end */
                    switch (*c) {
                    case '.':
    
                            /* Make sure we only do 3 dots .. */
                            if (n == 3) {   /* Whoops. Quit. */
                                    return 0;
                            }
                            n++;
                            c++;
                            break;
    
                    case '\0':
                            gotend = 1;
                            break;
    
                    default:
                            if (isspace((unsigned char)*c)) {
                                    gotend = 1;
                                    break;
                           } else {
                                   /* Invalid character, then fail. */
                                   return 0;
                           }
                   }
           }
   
           /* Concoct the address according to the number of parts specified. */
           switch (n) {
           case 0:                         /* a -- 32 bits */
   
                   /*
                    * Nothing is necessary here.  Overflow checking was
                    * already done in strtoul().
                    */
                   break;
           case 1:                         /* a.b -- 8.24 bits */
                   if (val > 0xffffff || parts[0] > 0xff) {
                           return 0;
                   }
                   val |= parts[0] << 24;
                   break;
   
           case 2:                         /* a.b.c -- 8.8.16 bits */
                   if (val > 0xffff || parts[0] > 0xff || parts[1] > 0xff) {
                           return 0;
                   }
                   val |= (parts[0] << 24) | (parts[1] << 16);
                   break;
   
           case 3:                         /* a.b.c.d -- 8.8.8.8 bits */
                   if (val > 0xff || parts[0] > 0xff || parts[1] > 0xff ||
                       parts[2] > 0xff) {
                           return 0;
                   }
                   val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
                   break;
           }
   
           if (addr != NULL) {
                   addr->s_addr = htonl(val);
           }
           return 1;
   }

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