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      1 /*	$OpenBSD: inet_addr.c,v 1.9 2005/08/06 20:30:03 espie Exp $	*/
      2 
      3 /*
      4  * ++Copyright++ 1983, 1990, 1993
      5  * -
      6  * Copyright (c) 1983, 1990, 1993
      7  *    The Regents of the University of California.  All rights reserved.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  * -
     33  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
     34  *
     35  * Permission to use, copy, modify, and distribute this software for any
     36  * purpose with or without fee is hereby granted, provided that the above
     37  * copyright notice and this permission notice appear in all copies, and that
     38  * the name of Digital Equipment Corporation not be used in advertising or
     39  * publicity pertaining to distribution of the document or software without
     40  * specific, written prior permission.
     41  *
     42  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
     43  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
     44  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
     45  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
     46  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
     47  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
     48  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
     49  * SOFTWARE.
     50  * -
     51  * --Copyright--
     52  */
     53 
     54 #include <sys/types.h>
     55 #include <sys/param.h>
     56 #include <netinet/in.h>
     57 #include <arpa/inet.h>
     58 #include <ctype.h>
     59 
     60 /*
     61  * Check whether "cp" is a valid ascii representation
     62  * of an Internet address and convert to a binary address.
     63  * Returns 1 if the address is valid, 0 if not.
     64  * This replaces inet_addr, the return value from which
     65  * cannot distinguish between failure and a local broadcast address.
     66  */
     67 int
     68 inet_aton(const char *cp, struct in_addr *addr)
     69 {
     70 	in_addr_t val;
     71 	int base, n;
     72 	char c;
     73 	u_int parts[4];
     74 	u_int *pp = parts;
     75 
     76 	c = *cp;
     77 	for (;;) {
     78 		/*
     79 		 * Collect number up to ``.''.
     80 		 * Values are specified as for C:
     81 		 * 0x=hex, 0=octal, isdigit=decimal.
     82 		 */
     83 		if (!isdigit(c))
     84 			return (0);
     85 		val = 0; base = 10;
     86 		if (c == '0') {
     87 			c = *++cp;
     88 			if (c == 'x' || c == 'X')
     89 				base = 16, c = *++cp;
     90 			else
     91 				base = 8;
     92 		}
     93 		for (;;) {
     94 			if (isascii(c) && isdigit(c)) {
     95 				val = (val * base) + (c - '0');
     96 				c = *++cp;
     97 			} else if (base == 16 && isascii(c) && isxdigit(c)) {
     98 				val = (val << 4) |
     99 					(c + 10 - (islower(c) ? 'a' : 'A'));
    100 				c = *++cp;
    101 			} else
    102 				break;
    103 		}
    104 		if (c == '.') {
    105 			/*
    106 			 * Internet format:
    107 			 *	a.b.c.d
    108 			 *	a.b.c	(with c treated as 16 bits)
    109 			 *	a.b	(with b treated as 24 bits)
    110 			 */
    111 			if (pp >= parts + 3)
    112 				return (0);
    113 			*pp++ = val;
    114 			c = *++cp;
    115 		} else
    116 			break;
    117 	}
    118 	/*
    119 	 * Check for trailing characters.
    120 	 */
    121 	if (c != '\0' && (!isascii(c) || !isspace(c)))
    122 		return (0);
    123 	/*
    124 	 * Concoct the address according to
    125 	 * the number of parts specified.
    126 	 */
    127 	n = pp - parts + 1;
    128 	switch (n) {
    129 
    130 	case 0:
    131 		return (0);		/* initial nondigit */
    132 
    133 	case 1:				/* a -- 32 bits */
    134 		break;
    135 
    136 	case 2:				/* a.b -- 8.24 bits */
    137 		if ((val > 0xffffff) || (parts[0] > 0xff))
    138 			return (0);
    139 		val |= parts[0] << 24;
    140 		break;
    141 
    142 	case 3:				/* a.b.c -- 8.8.16 bits */
    143 		if ((val > 0xffff) || (parts[0] > 0xff) || (parts[1] > 0xff))
    144 			return (0);
    145 		val |= (parts[0] << 24) | (parts[1] << 16);
    146 		break;
    147 
    148 	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
    149 		if ((val > 0xff) || (parts[0] > 0xff) || (parts[1] > 0xff) || (parts[2] > 0xff))
    150 			return (0);
    151 		val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
    152 		break;
    153 	}
    154 	if (addr)
    155 		addr->s_addr = htonl(val);
    156 	return (1);
    157 }
    158