xref: /freebsd/lib/libc/resolv/res_comp.c (revision 861249f5830e8658b61130e0ee7eaad2e93d0449)
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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  * 	This product includes software developed by the University of
16  * 	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 /*
35  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
36  *
37  * Permission to use, copy, modify, and distribute this software for any
38  * purpose with or without fee is hereby granted, provided that the above
39  * copyright notice and this permission notice appear in all copies, and that
40  * the name of Digital Equipment Corporation not be used in advertising or
41  * publicity pertaining to distribution of the document or software without
42  * specific, written prior permission.
43  *
44  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
45  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
46  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
47  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
48  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
49  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
50  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
51  * SOFTWARE.
52  */
53 
54 /*
55  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
56  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
57  *
58  * Permission to use, copy, modify, and distribute this software for any
59  * purpose with or without fee is hereby granted, provided that the above
60  * copyright notice and this permission notice appear in all copies.
61  *
62  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
63  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
64  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
65  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
66  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
67  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
68  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
69  */
70 
71 #if defined(LIBC_SCCS) && !defined(lint)
72 static const char sccsid[] = "@(#)res_comp.c	8.1 (Berkeley) 6/4/93";
73 static const char rcsid[] = "$Id: res_comp.c,v 1.3.18.2 2005/07/28 07:38:11 marka Exp $";
74 #endif /* LIBC_SCCS and not lint */
75 
76 #include "port_before.h"
77 #include <sys/types.h>
78 #include <sys/param.h>
79 #include <netinet/in.h>
80 #include <arpa/nameser.h>
81 #include <ctype.h>
82 #include <resolv.h>
83 #include <stdio.h>
84 #include <string.h>
85 #include <unistd.h>
86 #include "port_after.h"
87 
88 /*%
89  * Expand compressed domain name 'src' to full domain name.
90  *
91  * \li 'msg' is a pointer to the begining of the message,
92  * \li 'eom' points to the first location after the message,
93  * \li 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
94  * \li Return size of compressed name or -1 if there was an error.
95  */
96 int
97 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
98 	  char *dst, int dstsiz)
99 {
100 	int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
101 
102 	if (n > 0 && dst[0] == '.')
103 		dst[0] = '\0';
104 	return (n);
105 }
106 
107 /*%
108  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
109  *
110  * \li Return the size of the compressed name or -1.
111  * \li 'length' is the size of the array pointed to by 'comp_dn'.
112  */
113 int
114 dn_comp(const char *src, u_char *dst, int dstsiz,
115 	u_char **dnptrs, u_char **lastdnptr)
116 {
117 	return (ns_name_compress(src, dst, (size_t)dstsiz,
118 				 (const u_char **)dnptrs,
119 				 (const u_char **)lastdnptr));
120 }
121 
122 /*%
123  * Skip over a compressed domain name. Return the size or -1.
124  */
125 int
126 dn_skipname(const u_char *ptr, const u_char *eom) {
127 	const u_char *saveptr = ptr;
128 
129 	if (ns_name_skip(&ptr, eom) == -1)
130 		return (-1);
131 	return (ptr - saveptr);
132 }
133 
134 /*%
135  * Verify that a domain name uses an acceptable character set.
136  *
137  * Note the conspicuous absence of ctype macros in these definitions.  On
138  * non-ASCII hosts, we can't depend on string literals or ctype macros to
139  * tell us anything about network-format data.  The rest of the BIND system
140  * is not careful about this, but for some reason, we're doing it right here.
141  */
142 #define PERIOD 0x2e
143 #define	hyphenchar(c) ((c) == 0x2d)
144 #define bslashchar(c) ((c) == 0x5c)
145 #define periodchar(c) ((c) == PERIOD)
146 #define asterchar(c) ((c) == 0x2a)
147 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
148 		   || ((c) >= 0x61 && (c) <= 0x7a))
149 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
150 
151 #define borderchar(c) (alphachar(c) || digitchar(c))
152 #define middlechar(c) (borderchar(c) || hyphenchar(c))
153 #define	domainchar(c) ((c) > 0x20 && (c) < 0x7f)
154 
155 int
156 res_hnok(const char *dn) {
157 	int pch = PERIOD, ch = *dn++;
158 
159 	while (ch != '\0') {
160 		int nch = *dn++;
161 
162 		if (periodchar(ch)) {
163 			(void)NULL;
164 		} else if (periodchar(pch)) {
165 			if (!borderchar(ch))
166 				return (0);
167 		} else if (periodchar(nch) || nch == '\0') {
168 			if (!borderchar(ch))
169 				return (0);
170 		} else {
171 			if (!middlechar(ch))
172 				return (0);
173 		}
174 		pch = ch, ch = nch;
175 	}
176 	return (1);
177 }
178 
179 /*%
180  * hostname-like (A, MX, WKS) owners can have "*" as their first label
181  * but must otherwise be as a host name.
182  */
183 int
184 res_ownok(const char *dn) {
185 	if (asterchar(dn[0])) {
186 		if (periodchar(dn[1]))
187 			return (res_hnok(dn+2));
188 		if (dn[1] == '\0')
189 			return (1);
190 	}
191 	return (res_hnok(dn));
192 }
193 
194 /*%
195  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
196  * label, but the rest of the name has to look like a host name.
197  */
198 int
199 res_mailok(const char *dn) {
200 	int ch, escaped = 0;
201 
202 	/* "." is a valid missing representation */
203 	if (*dn == '\0')
204 		return (1);
205 
206 	/* otherwise <label>.<hostname> */
207 	while ((ch = *dn++) != '\0') {
208 		if (!domainchar(ch))
209 			return (0);
210 		if (!escaped && periodchar(ch))
211 			break;
212 		if (escaped)
213 			escaped = 0;
214 		else if (bslashchar(ch))
215 			escaped = 1;
216 	}
217 	if (periodchar(ch))
218 		return (res_hnok(dn));
219 	return (0);
220 }
221 
222 /*%
223  * This function is quite liberal, since RFC1034's character sets are only
224  * recommendations.
225  */
226 int
227 res_dnok(const char *dn) {
228 	int ch;
229 
230 	while ((ch = *dn++) != '\0')
231 		if (!domainchar(ch))
232 			return (0);
233 	return (1);
234 }
235 
236 #ifdef BIND_4_COMPAT
237 /*%
238  * This module must export the following externally-visible symbols:
239  *	___putlong
240  *	___putshort
241  *	__getlong
242  *	__getshort
243  * Note that one _ comes from C and the others come from us.
244  */
245 
246 #ifdef SOLARIS2
247 #ifdef  __putlong
248 #undef  __putlong
249 #endif
250 #ifdef  __putshort
251 #undef  __putshort
252 #endif
253 #pragma weak    putlong         =       __putlong
254 #pragma weak    putshort        =       __putshort
255 #endif /* SOLARIS2 */
256 
257 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
258 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
259 #ifndef __ultrix__
260 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
261 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
262 #endif /*__ultrix__*/
263 #endif /*BIND_4_COMPAT*/
264 
265 /*! \file */
266