inet_addr.c revision 1.9 
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 * Ascii internet address interpretation routine.
62 * The value returned is in network order.
63 */
64in_addr_t
65inet_addr(const char *cp)
66{
67	struct in_addr val;
68
69	if (inet_aton(cp, &val))
70		return (val.s_addr);
71	return (INADDR_NONE);
72}
73
74/*
75 * Check whether "cp" is a valid ascii representation
76 * of an Internet address and convert to a binary address.
77 * Returns 1 if the address is valid, 0 if not.
78 * This replaces inet_addr, the return value from which
79 * cannot distinguish between failure and a local broadcast address.
80 */
81int
82inet_aton(const char *cp, struct in_addr *addr)
83{
84	in_addr_t val;
85	int base, n;
86	char c;
87	u_int parts[4];
88	u_int *pp = parts;
89
90	c = *cp;
91	for (;;) {
92		/*
93		 * Collect number up to ``.''.
94		 * Values are specified as for C:
95		 * 0x=hex, 0=octal, isdigit=decimal.
96		 */
97		if (!isdigit(c))
98			return (0);
99		val = 0; base = 10;
100		if (c == '0') {
101			c = *++cp;
102			if (c == 'x' || c == 'X')
103				base = 16, c = *++cp;
104			else
105				base = 8;
106		}
107		for (;;) {
108			if (isascii(c) && isdigit(c)) {
109				val = (val * base) + (c - '0');
110				c = *++cp;
111			} else if (base == 16 && isascii(c) && isxdigit(c)) {
112				val = (val << 4) |
113					(c + 10 - (islower(c) ? 'a' : 'A'));
114				c = *++cp;
115			} else
116				break;
117		}
118		if (c == '.') {
119			/*
120			 * Internet format:
121			 *	a.b.c.d
122			 *	a.b.c	(with c treated as 16 bits)
123			 *	a.b	(with b treated as 24 bits)
124			 */
125			if (pp >= parts + 3)
126				return (0);
127			*pp++ = val;
128			c = *++cp;
129		} else
130			break;
131	}
132	/*
133	 * Check for trailing characters.
134	 */
135	if (c != '\0' && (!isascii(c) || !isspace(c)))
136		return (0);
137	/*
138	 * Concoct the address according to
139	 * the number of parts specified.
140	 */
141	n = pp - parts + 1;
142	switch (n) {
143
144	case 0:
145		return (0);		/* initial nondigit */
146
147	case 1:				/* a -- 32 bits */
148		break;
149
150	case 2:				/* a.b -- 8.24 bits */
151		if ((val > 0xffffff) || (parts[0] > 0xff))
152			return (0);
153		val |= parts[0] << 24;
154		break;
155
156	case 3:				/* a.b.c -- 8.8.16 bits */
157		if ((val > 0xffff) || (parts[0] > 0xff) || (parts[1] > 0xff))
158			return (0);
159		val |= (parts[0] << 24) | (parts[1] << 16);
160		break;
161
162	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
163		if ((val > 0xff) || (parts[0] > 0xff) || (parts[1] > 0xff) || (parts[2] > 0xff))
164			return (0);
165		val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
166		break;
167	}
168	if (addr)
169		addr->s_addr = htonl(val);
170	return (1);
171}
172