xref: /openbsd-src/lib/libc/net/inet_net_pton.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1 /*	$OpenBSD: inet_net_pton.c,v 1.1 1997/03/13 19:07:30 downsj Exp $	*/
2 
3 /*
4  * Copyright (c) 1996 by Internet Software Consortium.
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
11  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
12  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
13  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
14  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
15  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
16  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
17  * SOFTWARE.
18  */
19 
20 #if defined(LIBC_SCCS) && !defined(lint)
21 #if 0
22 static const char rcsid[] = "$From: inet_net_pton.c,v 8.3 1996/11/11 06:36:52 vixie Exp $";
23 #else
24 static const char rcsid[] = "$OpenBSD: inet_net_pton.c,v 1.1 1997/03/13 19:07:30 downsj Exp $";
25 #endif
26 #endif
27 
28 #include <sys/types.h>
29 #include <sys/socket.h>
30 #include <netinet/in.h>
31 #include <arpa/inet.h>
32 
33 #include <assert.h>
34 #include <ctype.h>
35 #include <errno.h>
36 #include <stdio.h>
37 #include <string.h>
38 #include <stdlib.h>
39 
40 static int	inet_net_pton_ipv4 __P((const char *src, u_char *dst,
41 					size_t size));
42 
43 /*
44  * static int
45  * inet_net_pton(af, src, dst, size)
46  *	convert network number from presentation to network format.
47  *	accepts hex octets, hex strings, decimal octets, and /CIDR.
48  *	"size" is in bytes and describes "dst".
49  * return:
50  *	number of bits, either imputed classfully or specified with /CIDR,
51  *	or -1 if some failure occurred (check errno).  ENOENT means it was
52  *	not a valid network specification.
53  * author:
54  *	Paul Vixie (ISC), June 1996
55  */
56 int
57 inet_net_pton(af, src, dst, size)
58 	int af;
59 	const char *src;
60 	void *dst;
61 	size_t size;
62 {
63 	switch (af) {
64 	case AF_INET:
65 		return (inet_net_pton_ipv4(src, dst, size));
66 	default:
67 		errno = EAFNOSUPPORT;
68 		return (-1);
69 	}
70 }
71 
72 /*
73  * static int
74  * inet_net_pton_ipv4(src, dst, size)
75  *	convert IPv4 network number from presentation to network format.
76  *	accepts hex octets, hex strings, decimal octets, and /CIDR.
77  *	"size" is in bytes and describes "dst".
78  * return:
79  *	number of bits, either imputed classfully or specified with /CIDR,
80  *	or -1 if some failure occurred (check errno).  ENOENT means it was
81  *	not an IPv4 network specification.
82  * note:
83  *	network byte order assumed.  this means 192.5.5.240/28 has
84  *	0x11110000 in its fourth octet.
85  * author:
86  *	Paul Vixie (ISC), June 1996
87  */
88 static int
89 inet_net_pton_ipv4(src, dst, size)
90 	const char *src;
91 	u_char *dst;
92 	size_t size;
93 {
94 	static const char
95 		xdigits[] = "0123456789abcdef",
96 		digits[] = "0123456789";
97 	int n, ch, tmp, dirty, bits;
98 	const u_char *odst = dst;
99 
100 	ch = *src++;
101 	if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
102 	    && isascii(src[1]) && isxdigit(src[1])) {
103 		/* Hexadecimal: Eat nybble string. */
104 		if (size <= 0)
105 			goto emsgsize;
106 		*dst = 0, dirty = 0;
107 		src++;	/* skip x or X. */
108 		while ((ch = *src++) != '\0' &&
109 		       isascii(ch) && isxdigit(ch)) {
110 			if (isupper(ch))
111 				ch = tolower(ch);
112 			n = strchr(xdigits, ch) - xdigits;
113 			assert(n >= 0 && n <= 15);
114 			*dst |= n;
115 			if (!dirty++)
116 				*dst <<= 4;
117 			else if (size-- > 0)
118 				*++dst = 0, dirty = 0;
119 			else
120 				goto emsgsize;
121 		}
122 		if (dirty)
123 			size--;
124 	} else if (isascii(ch) && isdigit(ch)) {
125 		/* Decimal: eat dotted digit string. */
126 		for (;;) {
127 			tmp = 0;
128 			do {
129 				n = strchr(digits, ch) - digits;
130 				assert(n >= 0 && n <= 9);
131 				tmp *= 10;
132 				tmp += n;
133 				if (tmp > 255)
134 					goto enoent;
135 			} while ((ch = *src++) != '\0' &&
136 				 isascii(ch) && isdigit(ch));
137 			if (size-- <= 0)
138 				goto emsgsize;
139 			*dst++ = (u_char) tmp;
140 			if (ch == '\0' || ch == '/')
141 				break;
142 			if (ch != '.')
143 				goto enoent;
144 			ch = *src++;
145 			if (!isascii(ch) || !isdigit(ch))
146 				goto enoent;
147 		}
148 	} else
149 		goto enoent;
150 
151 	bits = -1;
152 	if (ch == '/' && isascii(src[0]) && isdigit(src[0]) && dst > odst) {
153 		/* CIDR width specifier.  Nothing can follow it. */
154 		ch = *src++;	/* Skip over the /. */
155 		bits = 0;
156 		do {
157 			n = strchr(digits, ch) - digits;
158 			assert(n >= 0 && n <= 9);
159 			bits *= 10;
160 			bits += n;
161 		} while ((ch = *src++) != '\0' &&
162 			 isascii(ch) && isdigit(ch));
163 		if (ch != '\0')
164 			goto enoent;
165 		if (bits > 32)
166 			goto emsgsize;
167 	}
168 
169 	/* Firey death and destruction unless we prefetched EOS. */
170 	if (ch != '\0')
171 		goto enoent;
172 
173 	/* If nothing was written to the destination, we found no address. */
174 	if (dst == odst)
175 		goto enoent;
176 	/* If no CIDR spec was given, infer width from net class. */
177 	if (bits == -1) {
178 		if (*odst >= 240)	/* Class E */
179 			bits = 32;
180 		else if (*odst >= 224)	/* Class D */
181 			bits = 4;
182 		else if (*odst >= 192)	/* Class C */
183 			bits = 24;
184 		else if (*odst >= 128)	/* Class B */
185 			bits = 16;
186 		else			/* Class A */
187 			bits = 8;
188 		/* If imputed mask is narrower than specified octets, widen. */
189 		if (bits >= 8 && bits < ((dst - odst) * 8))
190 			bits = (dst - odst) * 8;
191 	}
192 	/* Extend network to cover the actual mask. */
193 	while (bits > ((dst - odst) * 8)) {
194 		if (size-- <= 0)
195 			goto emsgsize;
196 		*dst++ = '\0';
197 	}
198 	return (bits);
199 
200  enoent:
201 	errno = ENOENT;
202 	return (-1);
203 
204  emsgsize:
205 	errno = EMSGSIZE;
206 	return (-1);
207 }
208