1/*	$NetBSD: res_comp.c,v 1.14 2022/01/24 09:14:36 andvar Exp $	*/
2
3/*
4 * Copyright (c) 1985, 1993
5 *    The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32/*
33 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
34 *
35 * Permission to use, copy, modify, and distribute this software for any
36 * purpose with or without fee is hereby granted, provided that the above
37 * copyright notice and this permission notice appear in all copies, and that
38 * the name of Digital Equipment Corporation not be used in advertising or
39 * publicity pertaining to distribution of the document or software without
40 * specific, written prior permission.
41 *
42 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
43 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
44 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
45 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
46 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
47 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
48 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
49 * SOFTWARE.
50 */
51
52/*
53 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
54 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
55 *
56 * Permission to use, copy, modify, and distribute this software for any
57 * purpose with or without fee is hereby granted, provided that the above
58 * copyright notice and this permission notice appear in all copies.
59 *
60 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
61 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
62 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
63 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
64 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
65 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
66 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
67 */
68#include <sys/cdefs.h>
69#if defined(LIBC_SCCS) && !defined(lint)
70#ifdef notdef
71static const char sccsid[] = "@(#)res_comp.c	8.1 (Berkeley) 6/4/93";
72static const char rcsid[] = "Id: res_comp.c,v 1.5 2005/07/28 06:51:50 marka Exp";
73#else
74__RCSID("$NetBSD: res_comp.c,v 1.14 2022/01/24 09:14:36 andvar Exp $");
75#endif
76#endif /* LIBC_SCCS and not lint */
77
78#include "port_before.h"
79
80#include "namespace.h"
81#include <sys/types.h>
82#include <sys/param.h>
83#include <netinet/in.h>
84#include <arpa/nameser.h>
85#include <assert.h>
86#include <ctype.h>
87#include <resolv.h>
88#include <stdio.h>
89#include <string.h>
90#include <unistd.h>
91#include "port_after.h"
92
93#ifdef __weak_alias
94__weak_alias(dn_expand,_dn_expand)
95__weak_alias(dn_comp,__dn_comp)
96#if 0
97__weak_alias(dn_skipname,__dn_skipname)
98__weak_alias(res_hnok,__res_hnok)
99__weak_alias(res_ownok,__res_ownok)
100__weak_alias(res_mailok,__res_mailok)
101__weak_alias(res_dnok,__res_dnok)
102#endif
103#endif
104
105/*%
106 * Expand compressed domain name 'src' to full domain name.
107 *
108 * \li 'msg' is a pointer to the beginning of the message,
109 * \li 'eom' points to the first location after the message,
110 * \li 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
111 * \li Return size of compressed name or -1 if there was an error.
112 */
113int
114dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
115	  char *dst, int dstsiz)
116{
117	int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
118
119	if (n > 0 && dst[0] == '.')
120		dst[0] = '\0';
121	return (n);
122}
123
124/*%
125 * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
126 *
127 * \li Return the size of the compressed name or -1.
128 * \li 'length' is the size of the array pointed to by 'comp_dn'.
129 */
130int
131dn_comp(const char *src, u_char *dst, int dstsiz,
132	u_char **dnptrs, u_char **lastdnptr)
133{
134	return (ns_name_compress(src, dst, (size_t)dstsiz,
135				 (void *)dnptrs,
136				 (void *)lastdnptr));
137}
138
139/*%
140 * Skip over a compressed domain name. Return the size or -1.
141 */
142int
143dn_skipname(const u_char *ptr, const u_char *eom) {
144	const u_char *saveptr = ptr;
145
146	if (ns_name_skip(&ptr, eom) == -1)
147		return (-1);
148	_DIAGASSERT(__type_fit(int, ptr - saveptr));
149	return (int)(ptr - saveptr);
150}
151
152/*%
153 * Verify that a domain name uses an acceptable character set.
154 *
155 * Note the conspicuous absence of ctype macros in these definitions.  On
156 * non-ASCII hosts, we can't depend on string literals or ctype macros to
157 * tell us anything about network-format data.  The rest of the BIND system
158 * is not careful about this, but for some reason, we're doing it right here.
159 */
160#define PERIOD 0x2e
161#define	hyphenchar(c) ((c) == 0x2d)
162#define bslashchar(c) ((c) == 0x5c)
163#define periodchar(c) ((c) == PERIOD)
164#define asterchar(c) ((c) == 0x2a)
165#define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
166		   || ((c) >= 0x61 && (c) <= 0x7a))
167#define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
168
169#define borderchar(c) (alphachar(c) || digitchar(c))
170#define middlechar(c) (borderchar(c) || hyphenchar(c))
171#define	domainchar(c) ((c) > 0x20 && (c) < 0x7f)
172
173int
174res_hnok(const char *dn) {
175	int pch = PERIOD, ch = *dn++;
176
177	while (ch != '\0') {
178		int nch = *dn++;
179
180		if (periodchar(ch)) {
181			;
182		} else if (periodchar(pch)) {
183			if (!borderchar(ch))
184				return (0);
185		} else if (periodchar(nch) || nch == '\0') {
186			if (!borderchar(ch))
187				return (0);
188		} else {
189			if (!middlechar(ch))
190				return (0);
191		}
192		pch = ch, ch = nch;
193	}
194	return (1);
195}
196
197/*%
198 * hostname-like (A, MX, WKS) owners can have "*" as their first label
199 * but must otherwise be as a host name.
200 */
201int
202res_ownok(const char *dn) {
203	if (asterchar(dn[0])) {
204		if (periodchar(dn[1]))
205			return (res_hnok(dn+2));
206		if (dn[1] == '\0')
207			return (1);
208	}
209	return (res_hnok(dn));
210}
211
212/*%
213 * SOA RNAMEs and RP RNAMEs can have any printable character in their first
214 * label, but the rest of the name has to look like a host name.
215 */
216int
217res_mailok(const char *dn) {
218	int ch, escaped = 0;
219
220	/* "." is a valid missing representation */
221	if (*dn == '\0')
222		return (1);
223
224	/* otherwise <label>.<hostname> */
225	while ((ch = *dn++) != '\0') {
226		if (!domainchar(ch))
227			return (0);
228		if (!escaped && periodchar(ch))
229			break;
230		if (escaped)
231			escaped = 0;
232		else if (bslashchar(ch))
233			escaped = 1;
234	}
235	if (periodchar(ch))
236		return (res_hnok(dn));
237	return (0);
238}
239
240/*%
241 * This function is quite liberal, since RFC1034's character sets are only
242 * recommendations.
243 */
244int
245res_dnok(const char *dn) {
246	int ch;
247
248	while ((ch = *dn++) != '\0')
249		if (!domainchar(ch))
250			return (0);
251	return (1);
252}
253
254#ifdef BIND_4_COMPAT
255/*%
256 * This module must export the following externally-visible symbols:
257 *	___putlong
258 *	___putshort
259 *	__getlong
260 *	__getshort
261 * Note that one _ comes from C and the others come from us.
262 */
263
264#ifdef SOLARIS2
265#ifdef  __putlong
266#undef  __putlong
267#endif
268#ifdef  __putshort
269#undef  __putshort
270#endif
271#pragma weak    putlong         =       __putlong
272#pragma weak    putshort        =       __putshort
273#endif /* SOLARIS2 */
274
275void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
276void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
277#ifndef __ultrix__
278u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
279u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
280#endif /*__ultrix__*/
281#endif /*BIND_4_COMPAT*/
282
283/*! \file */
284