1/*	$NetBSD: res_comp.c,v 1.13 2015/02/24 17:56:20 christos 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
69#if defined(LIBC_SCCS) && !defined(lint)
70static const char sccsid[] = "@(#)res_comp.c	8.1 (Berkeley) 6/4/93";
71static const char rcsid[] = "$Id: res_comp.c,v 1.5 2005/07/28 06:51:50 marka Exp $";
72#endif /* LIBC_SCCS and not lint */
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 <assert.h>
80#include <ctype.h>
81#include <resolv.h>
82#include <stdio.h>
83#include <string.h>
84#include <unistd.h>
85#include "port_after.h"
86
87#ifdef __weak_alias
88__weak_alias(dn_expand,_dn_expand)
89__weak_alias(dn_comp,__dn_comp)
90#if 0
91__weak_alias(dn_skipname,__dn_skipname)
92__weak_alias(res_hnok,__res_hnok)
93__weak_alias(res_ownok,__res_ownok)
94__weak_alias(res_mailok,__res_mailok)
95__weak_alias(res_dnok,__res_dnok)
96#endif
97#endif
98
99/*%
100 * Expand compressed domain name 'src' to full domain name.
101 *
102 * \li 'msg' is a pointer to the begining of the message,
103 * \li 'eom' points to the first location after the message,
104 * \li 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
105 * \li Return size of compressed name or -1 if there was an error.
106 */
107int
108dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
109	  char *dst, int dstsiz)
110{
111	int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
112
113	if (n > 0 && dst[0] == '.')
114		dst[0] = '\0';
115	return (n);
116}
117
118/*%
119 * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
120 *
121 * \li Return the size of the compressed name or -1.
122 * \li 'length' is the size of the array pointed to by 'comp_dn'.
123 */
124int
125dn_comp(const char *src, u_char *dst, int dstsiz,
126	u_char **dnptrs, u_char **lastdnptr)
127{
128	return (ns_name_compress(src, dst, (size_t)dstsiz,
129				 (void *)dnptrs,
130				 (void *)lastdnptr));
131}
132
133/*%
134 * Skip over a compressed domain name. Return the size or -1.
135 */
136int
137dn_skipname(const u_char *ptr, const u_char *eom) {
138	const u_char *saveptr = ptr;
139
140	if (ns_name_skip(&ptr, eom) == -1)
141		return (-1);
142	assert(INT_MIN <= (ptr - saveptr) && (ptr - saveptr) <= INT_MAX);
143	return (int)(ptr - saveptr);
144}
145
146/*%
147 * Verify that a domain name uses an acceptable character set.
148 *
149 * Note the conspicuous absence of ctype macros in these definitions.  On
150 * non-ASCII hosts, we can't depend on string literals or ctype macros to
151 * tell us anything about network-format data.  The rest of the BIND system
152 * is not careful about this, but for some reason, we're doing it right here.
153 */
154#define PERIOD 0x2e
155#define	hyphenchar(c) ((c) == 0x2d || (c) == 0x5f)
156#define bslashchar(c) ((c) == 0x5c)
157#define periodchar(c) ((c) == PERIOD)
158#define asterchar(c) ((c) == 0x2a)
159#define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
160		   || ((c) >= 0x61 && (c) <= 0x7a))
161#define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
162
163#define borderchar(c) (alphachar(c) || digitchar(c))
164#define middlechar(c) (borderchar(c) || hyphenchar(c))
165#define	domainchar(c) ((c) > 0x20 && (c) < 0x7f)
166
167int
168res_hnok(const char *dn) {
169	int pch = PERIOD, ch = *dn++;
170
171	while (ch != '\0') {
172		int nch = *dn++;
173
174		if (periodchar(ch)) {
175			;
176		} else if (periodchar(pch)) {
177			if (!borderchar(ch))
178				return (0);
179		} else if (periodchar(nch) || nch == '\0') {
180			if (!borderchar(ch))
181				return (0);
182		} else {
183			if (!middlechar(ch))
184				return (0);
185		}
186		pch = ch, ch = nch;
187	}
188	return (1);
189}
190
191/*%
192 * hostname-like (A, MX, WKS) owners can have "*" as their first label
193 * but must otherwise be as a host name.
194 */
195int
196res_ownok(const char *dn) {
197	if (asterchar(dn[0])) {
198		if (periodchar(dn[1]))
199			return (res_hnok(dn+2));
200		if (dn[1] == '\0')
201			return (1);
202	}
203	return (res_hnok(dn));
204}
205
206/*%
207 * SOA RNAMEs and RP RNAMEs can have any printable character in their first
208 * label, but the rest of the name has to look like a host name.
209 */
210int
211res_mailok(const char *dn) {
212	int ch, escaped = 0;
213
214	/* "." is a valid missing representation */
215	if (*dn == '\0')
216		return (1);
217
218	/* otherwise <label>.<hostname> */
219	while ((ch = *dn++) != '\0') {
220		if (!domainchar(ch))
221			return (0);
222		if (!escaped && periodchar(ch))
223			break;
224		if (escaped)
225			escaped = 0;
226		else if (bslashchar(ch))
227			escaped = 1;
228	}
229	if (periodchar(ch))
230		return (res_hnok(dn));
231	return (0);
232}
233
234/*%
235 * This function is quite liberal, since RFC1034's character sets are only
236 * recommendations.
237 */
238int
239res_dnok(const char *dn) {
240	int ch;
241
242	while ((ch = *dn++) != '\0')
243		if (!domainchar(ch))
244			return (0);
245	return (1);
246}
247
248#ifdef BIND_4_COMPAT
249/*%
250 * This module must export the following externally-visible symbols:
251 *	___putlong
252 *	___putshort
253 *	__getlong
254 *	__getshort
255 * Note that one _ comes from C and the others come from us.
256 */
257
258#ifdef SOLARIS2
259#ifdef  __putlong
260#undef  __putlong
261#endif
262#ifdef  __putshort
263#undef  __putshort
264#endif
265#pragma weak    putlong         =       __putlong
266#pragma weak    putshort        =       __putshort
267#endif /* SOLARIS2 */
268
269void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
270void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
271#endif /*BIND_4_COMPAT*/
272
273#ifndef __ultrix__
274u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
275u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
276#endif /*__ultrix__*/
277
278/*! \file */
279