xref: /freebsd/lib/libc/inet/inet_cidr_pton.c (revision 3bdf775801b218aa5a89564839405b122f4b233e)
1 /*
2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3  * Copyright (c) 1998,1999 by Internet Software Consortium.
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static const char rcsid[] = "$Id: inet_cidr_pton.c,v 1.5.18.1 2005/04/27 05:00:53 sra Exp $";
20 #endif
21 #include <sys/cdefs.h>
22 __FBSDID("$FreeBSD$");
23 
24 #include "port_before.h"
25 
26 #include <sys/types.h>
27 #include <sys/socket.h>
28 #include <netinet/in.h>
29 #include <arpa/nameser.h>
30 #include <arpa/inet.h>
31 
32 #include <assert.h>
33 #include <ctype.h>
34 #include <errno.h>
35 #include <stdio.h>
36 #include <string.h>
37 #include <stdlib.h>
38 
39 #include "port_after.h"
40 
41 #ifdef SPRINTF_CHAR
42 # define SPRINTF(x) strlen(sprintf/**/x)
43 #else
44 # define SPRINTF(x) ((size_t)sprintf x)
45 #endif
46 
47 static int	inet_cidr_pton_ipv4 __P((const char *src, u_char *dst,
48 					 int *bits, int ipv6));
49 static int	inet_cidr_pton_ipv6 __P((const char *src, u_char *dst,
50 					 int *bits));
51 
52 static int	getbits(const char *, int ipv6);
53 
54 /*%
55  * int
56  * inet_cidr_pton(af, src, dst, *bits)
57  *	convert network address from presentation to network format.
58  *	accepts inet_pton()'s input for this "af" plus trailing "/CIDR".
59  *	"dst" is assumed large enough for its "af".  "bits" is set to the
60  *	/CIDR prefix length, which can have defaults (like /32 for IPv4).
61  * return:
62  *	-1 if an error occurred (inspect errno; ENOENT means bad format).
63  *	0 if successful conversion occurred.
64  * note:
65  *	192.5.5.1/28 has a nonzero host part, which means it isn't a network
66  *	as called for by inet_net_pton() but it can be a host address with
67  *	an included netmask.
68  * author:
69  *	Paul Vixie (ISC), October 1998
70  */
71 int
72 inet_cidr_pton(int af, const char *src, void *dst, int *bits) {
73 	switch (af) {
74 	case AF_INET:
75 		return (inet_cidr_pton_ipv4(src, dst, bits, 0));
76 	case AF_INET6:
77 		return (inet_cidr_pton_ipv6(src, dst, bits));
78 	default:
79 		errno = EAFNOSUPPORT;
80 		return (-1);
81 	}
82 }
83 
84 static const char digits[] = "0123456789";
85 
86 static int
87 inet_cidr_pton_ipv4(const char *src, u_char *dst, int *pbits, int ipv6) {
88 	const u_char *odst = dst;
89 	int n, ch, tmp, bits;
90 	size_t size = 4;
91 
92 	/* Get the mantissa. */
93 	while (ch = *src++, (isascii(ch) && isdigit(ch))) {
94 		tmp = 0;
95 		do {
96 			n = strchr(digits, ch) - digits;
97 			assert(n >= 0 && n <= 9);
98 			tmp *= 10;
99 			tmp += n;
100 			if (tmp > 255)
101 				goto enoent;
102 		} while ((ch = *src++) != '\0' && isascii(ch) && isdigit(ch));
103 		if (size-- == 0U)
104 			goto emsgsize;
105 		*dst++ = (u_char) tmp;
106 		if (ch == '\0' || ch == '/')
107 			break;
108 		if (ch != '.')
109 			goto enoent;
110 	}
111 
112 	/* Get the prefix length if any. */
113 	bits = -1;
114 	if (ch == '/' && dst > odst) {
115 		bits = getbits(src, ipv6);
116 		if (bits == -2)
117 			goto enoent;
118 	} else if (ch != '\0')
119 		goto enoent;
120 
121 	/* Prefix length can default to /32 only if all four octets spec'd. */
122 	if (bits == -1) {
123 		if (dst - odst == 4)
124 			bits = ipv6 ? 128 : 32;
125 		else
126 			goto enoent;
127 	}
128 
129 	/* If nothing was written to the destination, we found no address. */
130 	if (dst == odst)
131 		goto enoent;
132 
133 	/* If prefix length overspecifies mantissa, life is bad. */
134 	if (((bits - (ipv6 ? 96 : 0)) / 8) > (dst - odst))
135 		goto enoent;
136 
137 	/* Extend address to four octets. */
138 	while (size-- > 0U)
139 		*dst++ = 0;
140 
141 	*pbits = bits;
142 	return (0);
143 
144  enoent:
145 	errno = ENOENT;
146 	return (-1);
147 
148  emsgsize:
149 	errno = EMSGSIZE;
150 	return (-1);
151 }
152 
153 static int
154 inet_cidr_pton_ipv6(const char *src, u_char *dst, int *pbits) {
155 	static const char xdigits_l[] = "0123456789abcdef",
156 			  xdigits_u[] = "0123456789ABCDEF";
157 	u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
158 	const char *xdigits, *curtok;
159 	int ch, saw_xdigit;
160 	u_int val;
161 	int bits;
162 
163 	memset((tp = tmp), '\0', NS_IN6ADDRSZ);
164 	endp = tp + NS_IN6ADDRSZ;
165 	colonp = NULL;
166 	/* Leading :: requires some special handling. */
167 	if (*src == ':')
168 		if (*++src != ':')
169 			return (0);
170 	curtok = src;
171 	saw_xdigit = 0;
172 	val = 0;
173 	bits = -1;
174 	while ((ch = *src++) != '\0') {
175 		const char *pch;
176 
177 		if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
178 			pch = strchr((xdigits = xdigits_u), ch);
179 		if (pch != NULL) {
180 			val <<= 4;
181 			val |= (pch - xdigits);
182 			if (val > 0xffff)
183 				return (0);
184 			saw_xdigit = 1;
185 			continue;
186 		}
187 		if (ch == ':') {
188 			curtok = src;
189 			if (!saw_xdigit) {
190 				if (colonp)
191 					return (0);
192 				colonp = tp;
193 				continue;
194 			} else if (*src == '\0') {
195 				return (0);
196 			}
197 			if (tp + NS_INT16SZ > endp)
198 				return (0);
199 			*tp++ = (u_char) (val >> 8) & 0xff;
200 			*tp++ = (u_char) val & 0xff;
201 			saw_xdigit = 0;
202 			val = 0;
203 			continue;
204 		}
205 		if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
206 		    inet_cidr_pton_ipv4(curtok, tp, &bits, 1) == 0) {
207 			tp += NS_INADDRSZ;
208 			saw_xdigit = 0;
209 			break;	/*%< '\\0' was seen by inet_pton4(). */
210 		}
211 		if (ch == '/') {
212 			bits = getbits(src, 1);
213 			if (bits == -2)
214 				goto enoent;
215 			break;
216 		}
217 		goto enoent;
218 	}
219 	if (saw_xdigit) {
220 		if (tp + NS_INT16SZ > endp)
221 			goto emsgsize;
222 		*tp++ = (u_char) (val >> 8) & 0xff;
223 		*tp++ = (u_char) val & 0xff;
224 	}
225 	if (colonp != NULL) {
226 		/*
227 		 * Since some memmove()'s erroneously fail to handle
228 		 * overlapping regions, we'll do the shift by hand.
229 		 */
230 		const int n = tp - colonp;
231 		int i;
232 
233 		if (tp == endp)
234 			goto enoent;
235 		for (i = 1; i <= n; i++) {
236 			endp[- i] = colonp[n - i];
237 			colonp[n - i] = 0;
238 		}
239 		tp = endp;
240 	}
241 
242 	memcpy(dst, tmp, NS_IN6ADDRSZ);
243 
244 	*pbits = bits;
245 	return (0);
246 
247  enoent:
248 	errno = ENOENT;
249 	return (-1);
250 
251  emsgsize:
252 	errno = EMSGSIZE;
253 	return (-1);
254 }
255 
256 static int
257 getbits(const char *src, int ipv6) {
258 	int bits = 0;
259 	char *cp, ch;
260 
261 	if (*src == '\0')			/*%< syntax */
262 		return (-2);
263 	do {
264 		ch = *src++;
265 		cp = strchr(digits, ch);
266 		if (cp == NULL)			/*%< syntax */
267 			return (-2);
268 		bits *= 10;
269 		bits += cp - digits;
270 		if (bits == 0 && *src != '\0')	/*%< no leading zeros */
271 			return (-2);
272 		if (bits > (ipv6 ? 128 : 32))	/*%< range error */
273 			return (-2);
274 	} while (*src != '\0');
275 
276 	return (bits);
277 }
278 
279 /*! \file */
280