xref: /freebsd/lib/libc/resolv/res_comp.c (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
1 /*
2  * Copyright (c) 1985, 1993
3  *    The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 /*
31  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
32  *
33  * Permission to use, copy, modify, and distribute this software for any
34  * purpose with or without fee is hereby granted, provided that the above
35  * copyright notice and this permission notice appear in all copies, and that
36  * the name of Digital Equipment Corporation not be used in advertising or
37  * publicity pertaining to distribution of the document or software without
38  * specific, written prior permission.
39  *
40  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
41  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
42  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
43  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
44  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
45  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
46  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
47  * SOFTWARE.
48  */
49 
50 /*
51  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
52  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
53  *
54  * Permission to use, copy, modify, and distribute this software for any
55  * purpose with or without fee is hereby granted, provided that the above
56  * copyright notice and this permission notice appear in all copies.
57  *
58  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
59  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
60  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
61  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
62  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
63  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
64  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
65  */
66 
67 #if defined(LIBC_SCCS) && !defined(lint)
68 static const char sccsid[] = "@(#)res_comp.c	8.1 (Berkeley) 6/4/93";
69 static const char rcsid[] = "$Id: res_comp.c,v 1.5 2005/07/28 06:51:50 marka Exp $";
70 #endif /* LIBC_SCCS and not lint */
71 #include <sys/cdefs.h>
72 __FBSDID("$FreeBSD$");
73 
74 #include "port_before.h"
75 #include <sys/types.h>
76 #include <sys/param.h>
77 #include <netinet/in.h>
78 #include <arpa/nameser.h>
79 #include <ctype.h>
80 #include <resolv.h>
81 #include <stdio.h>
82 #include <string.h>
83 #include <unistd.h>
84 #include "port_after.h"
85 
86 /*%
87  * Expand compressed domain name 'src' to full domain name.
88  *
89  * \li 'msg' is a pointer to the begining of the message,
90  * \li 'eom' points to the first location after the message,
91  * \li 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
92  * \li Return size of compressed name or -1 if there was an error.
93  */
94 int
95 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
96 	  char *dst, int dstsiz)
97 {
98 	int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
99 
100 	if (n > 0 && dst[0] == '.')
101 		dst[0] = '\0';
102 	return (n);
103 }
104 
105 /*%
106  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
107  *
108  * \li Return the size of the compressed name or -1.
109  * \li 'length' is the size of the array pointed to by 'comp_dn'.
110  */
111 int
112 dn_comp(const char *src, u_char *dst, int dstsiz,
113 	u_char **dnptrs, u_char **lastdnptr)
114 {
115 	return (ns_name_compress(src, dst, (size_t)dstsiz,
116 				 (const u_char **)dnptrs,
117 				 (const u_char **)lastdnptr));
118 }
119 
120 /*%
121  * Skip over a compressed domain name. Return the size or -1.
122  */
123 int
124 dn_skipname(const u_char *ptr, const u_char *eom) {
125 	const u_char *saveptr = ptr;
126 
127 	if (ns_name_skip(&ptr, eom) == -1)
128 		return (-1);
129 	return (ptr - saveptr);
130 }
131 
132 /*%
133  * Verify that a domain name uses an acceptable character set.
134  *
135  * Note the conspicuous absence of ctype macros in these definitions.  On
136  * non-ASCII hosts, we can't depend on string literals or ctype macros to
137  * tell us anything about network-format data.  The rest of the BIND system
138  * is not careful about this, but for some reason, we're doing it right here.
139  */
140 #define PERIOD 0x2e
141 #define	hyphenchar(c) ((c) == 0x2d)
142 #define bslashchar(c) ((c) == 0x5c)
143 #define underscorechar(c) ((c) == 0x5f)
144 #define periodchar(c) ((c) == PERIOD)
145 #define asterchar(c) ((c) == 0x2a)
146 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
147 		   || ((c) >= 0x61 && (c) <= 0x7a))
148 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
149 
150 #ifdef	RES_ENFORCE_RFC1034
151 #define borderchar(c) (alphachar(c) || digitchar(c))
152 #else
153 #define borderchar(c) (alphachar(c) || digitchar(c) || underscorechar(c))
154 #endif
155 #define middlechar(c) (borderchar(c) || hyphenchar(c))
156 #define	domainchar(c) ((c) > 0x20 && (c) < 0x7f)
157 
158 int
159 res_hnok(const char *dn) {
160 	int pch = PERIOD, ch = *dn++;
161 
162 	while (ch != '\0') {
163 		int nch = *dn++;
164 
165 		if (periodchar(ch)) {
166 			(void)NULL;
167 		} else if (periodchar(pch)) {
168 			if (!borderchar(ch))
169 				return (0);
170 		} else if (periodchar(nch) || nch == '\0') {
171 			if (!borderchar(ch))
172 				return (0);
173 		} else {
174 			if (!middlechar(ch))
175 				return (0);
176 		}
177 		pch = ch, ch = nch;
178 	}
179 	return (1);
180 }
181 
182 /*%
183  * hostname-like (A, MX, WKS) owners can have "*" as their first label
184  * but must otherwise be as a host name.
185  */
186 int
187 res_ownok(const char *dn) {
188 	if (asterchar(dn[0])) {
189 		if (periodchar(dn[1]))
190 			return (res_hnok(dn+2));
191 		if (dn[1] == '\0')
192 			return (1);
193 	}
194 	return (res_hnok(dn));
195 }
196 
197 /*%
198  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
199  * label, but the rest of the name has to look like a host name.
200  */
201 int
202 res_mailok(const char *dn) {
203 	int ch, escaped = 0;
204 
205 	/* "." is a valid missing representation */
206 	if (*dn == '\0')
207 		return (1);
208 
209 	/* otherwise <label>.<hostname> */
210 	while ((ch = *dn++) != '\0') {
211 		if (!domainchar(ch))
212 			return (0);
213 		if (!escaped && periodchar(ch))
214 			break;
215 		if (escaped)
216 			escaped = 0;
217 		else if (bslashchar(ch))
218 			escaped = 1;
219 	}
220 	if (periodchar(ch))
221 		return (res_hnok(dn));
222 	return (0);
223 }
224 
225 /*%
226  * This function is quite liberal, since RFC1034's character sets are only
227  * recommendations.
228  */
229 int
230 res_dnok(const char *dn) {
231 	int ch;
232 
233 	while ((ch = *dn++) != '\0')
234 		if (!domainchar(ch))
235 			return (0);
236 	return (1);
237 }
238 
239 #ifdef BIND_4_COMPAT
240 /*%
241  * This module must export the following externally-visible symbols:
242  *	___putlong
243  *	___putshort
244  *	__getlong
245  *	__getshort
246  * Note that one _ comes from C and the others come from us.
247  */
248 
249 #ifdef SOLARIS2
250 #ifdef  __putlong
251 #undef  __putlong
252 #endif
253 #ifdef  __putshort
254 #undef  __putshort
255 #endif
256 #pragma weak    putlong         =       __putlong
257 #pragma weak    putshort        =       __putshort
258 #endif /* SOLARIS2 */
259 
260 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
261 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
262 #ifndef __ultrix__
263 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
264 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
265 #endif /*__ultrix__*/
266 #endif /*BIND_4_COMPAT*/
267 
268 /*
269  * Weak aliases for applications that use certain private entry points,
270  * and fail to include <resolv.h>.
271  */
272 #undef dn_comp
273 __weak_reference(__dn_comp, dn_comp);
274 #undef dn_expand
275 __weak_reference(__dn_expand, dn_expand);
276 
277 /*! \file */
278