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
36 int
inet_aton(const char * cp,struct in_addr * addr)37 inet_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