1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2001 Charles Mott <[email protected]>
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 #include <sys/param.h>
31 #include <sys/ctype.h>
32 #include <sys/limits.h>
33 #include <sys/systm.h>
34
35 #include <netinet/in.h>
36
37 int
inet_aton(const char * cp,struct in_addr * addr)38 inet_aton(const char *cp, struct in_addr *addr)
39 {
40 u_long parts[4];
41 in_addr_t val;
42 const char *c;
43 char *endptr;
44 int gotend, n;
45
46 c = (const char *)cp;
47 n = 0;
48
49 /*
50 * Run through the string, grabbing numbers until
51 * the end of the string, or some error
52 */
53 gotend = 0;
54 while (!gotend) {
55 unsigned long l;
56
57 l = strtoul(c, &endptr, 0);
58
59 if (l == ULONG_MAX || (l == 0 && endptr == c))
60 return (0);
61
62 val = (in_addr_t)l;
63
64 /*
65 * If the whole string is invalid, endptr will equal
66 * c.. this way we can make sure someone hasn't
67 * gone '.12' or something which would get past
68 * the next check.
69 */
70 if (endptr == c)
71 return (0);
72 parts[n] = val;
73 c = endptr;
74
75 /* Check the next character past the previous number's end */
76 switch (*c) {
77 case '.' :
78
79 /* Make sure we only do 3 dots .. */
80 if (n == 3) /* Whoops. Quit. */
81 return (0);
82 n++;
83 c++;
84 break;
85
86 case '\0':
87 gotend = 1;
88 break;
89
90 default:
91 if (isspace((unsigned char)*c)) {
92 gotend = 1;
93 break;
94 } else {
95 /* Invalid character, then fail. */
96 return (0);
97 }
98 }
99 }
100
101 /* Concoct the address according to the number of parts specified. */
102 switch (n) {
103 case 0: /* a -- 32 bits */
104
105 /*
106 * Nothing is necessary here. Overflow checking was
107 * already done in strtoul().
108 */
109 break;
110 case 1: /* a.b -- 8.24 bits */
111 if (val > 0xffffff || parts[0] > 0xff)
112 return (0);
113 val |= parts[0] << 24;
114 break;
115
116 case 2: /* a.b.c -- 8.8.16 bits */
117 if (val > 0xffff || parts[0] > 0xff || parts[1] > 0xff)
118 return (0);
119 val |= (parts[0] << 24) | (parts[1] << 16);
120 break;
121
122 case 3: /* a.b.c.d -- 8.8.8.8 bits */
123 if (val > 0xff || parts[0] > 0xff || parts[1] > 0xff ||
124 parts[2] > 0xff)
125 return (0);
126 val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
127 break;
128 }
129
130 if (addr != NULL)
131 addr->s_addr = htonl(val);
132 return (1);
133 }
134