xref: /openbsd-src/lib/libc/net/inet_addr.c (revision e9b2b68ca3a6cce2632b4a73cc801bbb6f19c001)
1 /*
2  * Copyright (c) 1983, 1990, 1993
3  *	The Regents of the University of California.  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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. 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 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char rcsid[] = "$OpenBSD: inet_addr.c,v 1.3 1996/08/19 08:29:08 tholo Exp $";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <sys/param.h>
39 #include <netinet/in.h>
40 #include <arpa/inet.h>
41 #include <ctype.h>
42 
43 /*
44  * Ascii internet address interpretation routine.
45  * The value returned is in network order.
46  */
47 u_long
48 inet_addr(cp)
49 	register const char *cp;
50 {
51 	struct in_addr val;
52 
53 	if (inet_aton(cp, &val))
54 		return (val.s_addr);
55 	return (INADDR_NONE);
56 }
57 
58 /*
59  * Check whether "cp" is a valid ascii representation
60  * of an Internet address and convert to a binary address.
61  * Returns 1 if the address is valid, 0 if not.
62  * This replaces inet_addr, the return value from which
63  * cannot distinguish between failure and a local broadcast address.
64  */
65 int
66 inet_aton(cp, addr)
67 	register const char *cp;
68 	struct in_addr *addr;
69 {
70 	register u_long val;
71 	register int base, n;
72 	register char c;
73 	u_int parts[4];
74 	register u_int *pp = parts;
75 
76 	for (;;) {
77 		/*
78 		 * Collect number up to ``.''.
79 		 * Values are specified as for C:
80 		 * 0x=hex, 0=octal, other=decimal.
81 		 */
82 		val = 0; base = 10;
83 		if (*cp == '0') {
84 			if (*++cp == 'x' || *cp == 'X')
85 				base = 16, cp++;
86 			else
87 				base = 8;
88 		}
89 		while ((c = *cp) != '\0') {
90 			if (isascii(c) && isdigit(c)) {
91 				val = (val * base) + (c - '0');
92 				cp++;
93 				continue;
94 			}
95 			if (base == 16 && isascii(c) && isxdigit(c)) {
96 				val = (val << 4) +
97 					(c + 10 - (islower(c) ? 'a' : 'A'));
98 				cp++;
99 				continue;
100 			}
101 			break;
102 		}
103 		if (*cp == '.') {
104 			/*
105 			 * Internet format:
106 			 *	a.b.c.d
107 			 *	a.b.c	(with c treated as 16-bits)
108 			 *	a.b	(with b treated as 24 bits)
109 			 */
110 			if (pp >= parts + 3 || val > 0xff)
111 				return (0);
112 			*pp++ = val, cp++;
113 		} else
114 			break;
115 	}
116 	/*
117 	 * Check for trailing characters.
118 	 */
119 	if (*cp && (!isascii(*cp) || !isspace(*cp)))
120 		return (0);
121 	/*
122 	 * Concoct the address according to
123 	 * the number of parts specified.
124 	 */
125 	n = pp - parts + 1;
126 	switch (n) {
127 
128 	case 0:
129 		return (0);		/* initial nondigit */
130 
131 	case 1:				/* a -- 32 bits */
132 		break;
133 
134 	case 2:				/* a.b -- 8.24 bits */
135 		if (val > 0xffffff)
136 			return (0);
137 		val |= parts[0] << 24;
138 		break;
139 
140 	case 3:				/* a.b.c -- 8.8.16 bits */
141 		if (val > 0xffff)
142 			return (0);
143 		val |= (parts[0] << 24) | (parts[1] << 16);
144 		break;
145 
146 	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
147 		if (val > 0xff)
148 			return (0);
149 		val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
150 		break;
151 	}
152 	if (addr)
153 		addr->s_addr = htonl(val);
154 	return (1);
155 }
156