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