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)
68static const char sccsid[] = "@(#)res_comp.c	8.1 (Berkeley) 6/4/93";
69static 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/param.h>
76#include <netinet/in.h>
77#include <arpa/nameser.h>
78#include <ctype.h>
79#include <resolv.h>
80#include <stdio.h>
81#include <string.h>
82#include <unistd.h>
83#include "port_after.h"
84
85/*%
86 * Expand compressed domain name 'src' to full domain name.
87 *
88 * \li 'msg' is a pointer to the beginning of the message,
89 * \li 'eom' points to the first location after the message,
90 * \li 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
91 * \li Return size of compressed name or -1 if there was an error.
92 */
93int
94dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
95	  char *dst, int dstsiz)
96{
97	int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
98
99	if (n > 0 && dst[0] == '.')
100		dst[0] = '\0';
101	return (n);
102}
103
104/*%
105 * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
106 *
107 * \li Return the size of the compressed name or -1.
108 * \li 'length' is the size of the array pointed to by 'comp_dn'.
109 */
110int
111dn_comp(const char *src, u_char *dst, int dstsiz,
112	u_char **dnptrs, u_char **lastdnptr)
113{
114	return (ns_name_compress(src, dst, (size_t)dstsiz,
115				 (const u_char **)dnptrs,
116				 (const u_char **)lastdnptr));
117}
118
119/*%
120 * Skip over a compressed domain name. Return the size or -1.
121 */
122int
123dn_skipname(const u_char *ptr, const u_char *eom) {
124	const u_char *saveptr = ptr;
125
126	if (ns_name_skip(&ptr, eom) == -1)
127		return (-1);
128	return (ptr - saveptr);
129}
130
131/*%
132 * Verify that a domain name uses an acceptable character set.
133 *
134 * Note the conspicuous absence of ctype macros in these definitions.  On
135 * non-ASCII hosts, we can't depend on string literals or ctype macros to
136 * tell us anything about network-format data.  The rest of the BIND system
137 * is not careful about this, but for some reason, we're doing it right here.
138 */
139#define PERIOD 0x2e
140#define	hyphenchar(c) ((c) == 0x2d)
141#define bslashchar(c) ((c) == 0x5c)
142#define underscorechar(c) ((c) == 0x5f)
143#define periodchar(c) ((c) == PERIOD)
144#define asterchar(c) ((c) == 0x2a)
145#define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
146		   || ((c) >= 0x61 && (c) <= 0x7a))
147#define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
148
149#ifdef	RES_ENFORCE_RFC1034
150#define borderchar(c) (alphachar(c) || digitchar(c))
151#else
152#define borderchar(c) (alphachar(c) || digitchar(c) || underscorechar(c))
153#endif
154#define middlechar(c) (borderchar(c) || hyphenchar(c))
155#define	domainchar(c) ((c) > 0x20 && (c) < 0x7f)
156
157int
158res_hnok(const char *dn) {
159	int pch = PERIOD, ch = *dn++;
160
161	while (ch != '\0') {
162		int nch = *dn++;
163
164		if (periodchar(ch)) {
165			(void)NULL;
166		} else if (periodchar(pch)) {
167			if (!borderchar(ch))
168				return (0);
169		} else if (periodchar(nch) || nch == '\0') {
170			if (!borderchar(ch))
171				return (0);
172		} else {
173			if (!middlechar(ch))
174				return (0);
175		}
176		pch = ch, ch = nch;
177	}
178	return (1);
179}
180
181/*%
182 * hostname-like (A, MX, WKS) owners can have "*" as their first label
183 * but must otherwise be as a host name.
184 */
185int
186res_ownok(const char *dn) {
187	if (asterchar(dn[0])) {
188		if (periodchar(dn[1]))
189			return (res_hnok(dn+2));
190		if (dn[1] == '\0')
191			return (1);
192	}
193	return (res_hnok(dn));
194}
195
196/*%
197 * SOA RNAMEs and RP RNAMEs can have any printable character in their first
198 * label, but the rest of the name has to look like a host name.
199 */
200int
201res_mailok(const char *dn) {
202	int ch, escaped = 0;
203
204	/* "." is a valid missing representation */
205	if (*dn == '\0')
206		return (1);
207
208	/* otherwise <label>.<hostname> */
209	while ((ch = *dn++) != '\0') {
210		if (!domainchar(ch))
211			return (0);
212		if (!escaped && periodchar(ch))
213			break;
214		if (escaped)
215			escaped = 0;
216		else if (bslashchar(ch))
217			escaped = 1;
218	}
219	if (periodchar(ch))
220		return (res_hnok(dn));
221	return (0);
222}
223
224/*%
225 * This function is quite liberal, since RFC1034's character sets are only
226 * recommendations.
227 */
228int
229res_dnok(const char *dn) {
230	int ch;
231
232	while ((ch = *dn++) != '\0')
233		if (!domainchar(ch))
234			return (0);
235	return (1);
236}
237
238#ifdef BIND_4_COMPAT
239/*%
240 * This module must export the following externally-visible symbols:
241 *	___putlong
242 *	___putshort
243 *	__getlong
244 *	__getshort
245 * Note that one _ comes from C and the others come from us.
246 */
247
248#ifdef SOLARIS2
249#ifdef  __putlong
250#undef  __putlong
251#endif
252#ifdef  __putshort
253#undef  __putshort
254#endif
255#pragma weak    putlong         =       __putlong
256#pragma weak    putshort        =       __putshort
257#endif /* SOLARIS2 */
258
259void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
260void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
261#ifndef __ultrix__
262u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
263u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
264#endif /*__ultrix__*/
265#endif /*BIND_4_COMPAT*/
266
267/*
268 * Weak aliases for applications that use certain private entry points,
269 * and fail to include <resolv.h>.
270 */
271#undef dn_comp
272__weak_reference(__dn_comp, dn_comp);
273#undef dn_expand
274__weak_reference(__dn_expand, dn_expand);
275
276/*! \file */
277