1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/param.h>
33#include <sys/ctype.h>
34#include <sys/limits.h>
35#include <sys/systm.h>
36
37#include <netinet/in.h>
38
39int
40inet_aton(const char *cp, struct in_addr *addr)
41{
42	u_long parts[4];
43	in_addr_t val;
44	const char *c;
45	char *endptr;
46	int gotend, n;
47
48	c = (const char *)cp;
49	n = 0;
50
51	/*
52	 * Run through the string, grabbing numbers until
53	 * the end of the string, or some error
54	 */
55	gotend = 0;
56	while (!gotend) {
57		unsigned long l;
58
59		l = strtoul(c, &endptr, 0);
60
61		if (l == ULONG_MAX || (l == 0 && endptr == c))
62			return (0);
63
64		val = (in_addr_t)l;
65
66		/*
67		 * If the whole string is invalid, endptr will equal
68		 * c.. this way we can make sure someone hasn't
69		 * gone '.12' or something which would get past
70		 * the next check.
71		 */
72		if (endptr == c)
73			return (0);
74		parts[n] = val;
75		c = endptr;
76
77		/* Check the next character past the previous number's end */
78		switch (*c) {
79		case '.' :
80
81			/* Make sure we only do 3 dots .. */
82			if (n == 3)	/* Whoops. Quit. */
83				return (0);
84			n++;
85			c++;
86			break;
87
88		case '\0':
89			gotend = 1;
90			break;
91
92		default:
93			if (isspace((unsigned char)*c)) {
94				gotend = 1;
95				break;
96			} else {
97				/* Invalid character, then fail. */
98				return (0);
99			}
100		}
101	}
102
103	/* Concoct the address according to the number of parts specified. */
104	switch (n) {
105	case 0:				/* a -- 32 bits */
106
107		/*
108		 * Nothing is necessary here.  Overflow checking was
109		 * already done in strtoul().
110		 */
111		break;
112	case 1:				/* a.b -- 8.24 bits */
113		if (val > 0xffffff || parts[0] > 0xff)
114			return (0);
115		val |= parts[0] << 24;
116		break;
117
118	case 2:				/* a.b.c -- 8.8.16 bits */
119		if (val > 0xffff || parts[0] > 0xff || parts[1] > 0xff)
120			return (0);
121		val |= (parts[0] << 24) | (parts[1] << 16);
122		break;
123
124	case 3:				/* a.b.c.d -- 8.8.8.8 bits */
125		if (val > 0xff || parts[0] > 0xff || parts[1] > 0xff ||
126		    parts[2] > 0xff)
127			return (0);
128		val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
129		break;
130	}
131
132	if (addr != NULL)
133		addr->s_addr = htonl(val);
134	return (1);
135}
136