1 /*	$OpenBSD: inet_net_pton.c,v 1.14 2022/12/27 17:10:06 jmc Exp $	*/
2 
3 /*
4  * Copyright (c) 2012 by Gilles Chehade <gilles@openbsd.org>
5  * Copyright (c) 1996,1999 by Internet Software Consortium.
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
12  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
13  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
14  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
15  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
16  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
17  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
18  * SOFTWARE.
19  */
20 
21 #include "openbsd-compat.h"
22 
23 #if !defined(HAVE_INET_NET_PTON) || defined(HAVE_LIBBSD)
24 
25 #include <sys/types.h>
26 #include <sys/socket.h>
27 #include <netinet/in.h>
28 #include <arpa/inet.h>
29 
30 #include <assert.h>
31 #include <ctype.h>
32 #include <errno.h>
33 #include <stdio.h>
34 #include <string.h>
35 #include <stdlib.h>
36 
37 static int	inet_net_pton_ipv4(const char *, u_char *, size_t);
38 static int	inet_net_pton_ipv6(const char *, u_char *, size_t);
39 
40 /*
41  * static int
42  * inet_net_pton(af, src, dst, size)
43  *	convert network number from presentation to network format.
44  *	accepts hex octets, hex strings, decimal octets, and /CIDR.
45  *	"size" is in bytes and describes "dst".
46  * return:
47  *	number of bits, either imputed classfully or specified with /CIDR,
48  *	or -1 if some failure occurred (check errno).  ENOENT means it was
49  *	not a valid network specification.
50  * author:
51  *	Paul Vixie (ISC), June 1996
52  */
53 int
54 inet_net_pton(int af, const char *src, void *dst, size_t size)
55 {
56 	switch (af) {
57 	case AF_INET:
58 		return (inet_net_pton_ipv4(src, dst, size));
59 	case AF_INET6:
60 		return (inet_net_pton_ipv6(src, dst, size));
61 	default:
62 		errno = EAFNOSUPPORT;
63 		return (-1);
64 	}
65 }
66 
67 /*
68  * static int
69  * inet_net_pton_ipv4(src, dst, size)
70  *	convert IPv4 network number from presentation to network format.
71  *	accepts hex octets, hex strings, decimal octets, and /CIDR.
72  *	"size" is in bytes and describes "dst".
73  * return:
74  *	number of bits, either imputed classfully or specified with /CIDR,
75  *	or -1 if some failure occurred (check errno).  ENOENT means it was
76  *	not an IPv4 network specification.
77  * note:
78  *	network byte order assumed.  this means 192.5.5.240/28 has
79  *	0x11110000 in its fourth octet.
80  * author:
81  *	Paul Vixie (ISC), June 1996
82  */
83 static int
84 inet_net_pton_ipv4(const char *src, u_char *dst, size_t size)
85 {
86 	static const char
87 		xdigits[] = "0123456789abcdef",
88 		digits[] = "0123456789";
89 	int n, ch, tmp, dirty, bits;
90 	const u_char *odst = dst;
91 
92 	ch = (unsigned char)*src++;
93 	if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
94 	    && isascii((unsigned char)src[1]) && isxdigit((unsigned char)src[1])) {
95 		/* Hexadecimal: Eat nybble string. */
96 		if (size == 0)
97 			goto emsgsize;
98 		tmp = 0, dirty = 0;
99 		src++;	/* skip x or X. */
100 		while ((ch = (unsigned char)*src++) != '\0' &&
101 		    isascii(ch) && isxdigit(ch)) {
102 			if (isupper(ch))
103 				ch = tolower(ch);
104 			n = strchr(xdigits, ch) - xdigits;
105 			assert(n >= 0 && n <= 15);
106 			if (dirty == 0)
107 				tmp = n;
108 			else
109 				tmp = (tmp << 4) | n;
110 			if (++dirty == 2) {
111 				if (size-- == 0)
112 					goto emsgsize;
113 				*dst++ = (u_char) tmp;
114 				dirty = 0;
115 			}
116 		}
117 		if (dirty) {  /* Odd trailing nybble? */
118 			if (size-- == 0)
119 				goto emsgsize;
120 			*dst++ = (u_char) (tmp << 4);
121 		}
122 	} else if (isascii(ch) && isdigit(ch)) {
123 		/* Decimal: eat dotted digit string. */
124 		for (;;) {
125 			tmp = 0;
126 			do {
127 				n = strchr(digits, ch) - digits;
128 				assert(n >= 0 && n <= 9);
129 				tmp *= 10;
130 				tmp += n;
131 				if (tmp > 255)
132 					goto enoent;
133 			} while ((ch = (unsigned char)*src++) != '\0' &&
134 				 isascii(ch) && isdigit(ch));
135 			if (size-- == 0)
136 				goto emsgsize;
137 			*dst++ = (u_char) tmp;
138 			if (ch == '\0' || ch == '/')
139 				break;
140 			if (ch != '.')
141 				goto enoent;
142 			ch = (unsigned char)*src++;
143 			if (!isascii(ch) || !isdigit(ch))
144 				goto enoent;
145 		}
146 	} else
147 		goto enoent;
148 
149 	bits = -1;
150 	if (ch == '/' && isascii((unsigned char)src[0]) &&
151 	    isdigit((unsigned char)src[0]) && dst > odst) {
152 		/* CIDR width specifier.  Nothing can follow it. */
153 		ch = (unsigned char)*src++;	/* Skip over the /. */
154 		bits = 0;
155 		do {
156 			n = strchr(digits, ch) - digits;
157 			assert(n >= 0 && n <= 9);
158 			bits *= 10;
159 			bits += n;
160 			if (bits > 32)
161 				goto emsgsize;
162 		} while ((ch = (unsigned char)*src++) != '\0' &&
163 			 isascii(ch) && isdigit(ch));
164 		if (ch != '\0')
165 			goto enoent;
166 	}
167 
168 	/* Fiery death and destruction unless we prefetched EOS. */
169 	if (ch != '\0')
170 		goto enoent;
171 
172 	/* If nothing was written to the destination, we found no address. */
173 	if (dst == odst)
174 		goto enoent;
175 	/* If no CIDR spec was given, infer width from net class. */
176 	if (bits == -1) {
177 		if (*odst >= 240)	/* Class E */
178 			bits = 32;
179 		else if (*odst >= 224)	/* Class D */
180 			bits = 4;
181 		else if (*odst >= 192)	/* Class C */
182 			bits = 24;
183 		else if (*odst >= 128)	/* Class B */
184 			bits = 16;
185 		else			/* Class A */
186 			bits = 8;
187 		/* If imputed mask is narrower than specified octets, widen. */
188 		if (bits < ((dst - odst) * 8))
189 			bits = (dst - odst) * 8;
190 	}
191 	/* Extend network to cover the actual mask. */
192 	while (bits > ((dst - odst) * 8)) {
193 		if (size-- == 0)
194 			goto emsgsize;
195 		*dst++ = '\0';
196 	}
197 	return (bits);
198 
199  enoent:
200 	errno = ENOENT;
201 	return (-1);
202 
203  emsgsize:
204 	errno = EMSGSIZE;
205 	return (-1);
206 }
207 
208 
209 static int
210 inet_net_pton_ipv6(const char *src, u_char *dst, size_t size)
211 {
212 	struct in6_addr	 in6;
213 	int		 ret;
214 	int		 bits;
215 	size_t		 bytes;
216 	char		 buf[INET6_ADDRSTRLEN + sizeof("/128")];
217 	char		*sep;
218 	const char	*errstr;
219 
220 	if (strlcpy(buf, src, sizeof buf) >= sizeof buf) {
221 		errno = EMSGSIZE;
222 		return (-1);
223 	}
224 
225 	sep = strchr(buf, '/');
226 	if (sep != NULL)
227 		*sep++ = '\0';
228 
229 	ret = inet_pton(AF_INET6, buf, &in6);
230 	if (ret != 1)
231 		return (-1);
232 
233 	if (sep == NULL)
234 		bits = 128;
235 	else {
236 		bits = strtonum(sep, 0, 128, &errstr);
237 		if (errstr) {
238 			errno = EINVAL;
239 			return (-1);
240 		}
241 	}
242 
243 	bytes = (bits + 7) / 8;
244 	if (bytes > size) {
245 		errno = EMSGSIZE;
246 		return (-1);
247 	}
248 	memcpy(dst, &in6.s6_addr, bytes);
249 	return (bits);
250 }
251 
252 #endif