res_comp.c revision 170244 
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 1.3.18.2 2005/07/28 07:38:11 marka Exp $";
70#endif /* LIBC_SCCS and not lint */
71#include <sys/cdefs.h>
72__FBSDID("$FreeBSD: head/lib/libc/resolv/res_comp.c 170244 2007-06-03 17:20:27Z ume $");
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 */
94int
95dn_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 */
111int
112dn_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 */
123int
124dn_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 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#define borderchar(c) (alphachar(c) || digitchar(c))
150#define middlechar(c) (borderchar(c) || hyphenchar(c))
151#define	domainchar(c) ((c) > 0x20 && (c) < 0x7f)
152
153int
154res_hnok(const char *dn) {
155	int pch = PERIOD, ch = *dn++;
156
157	while (ch != '\0') {
158		int nch = *dn++;
159
160		if (periodchar(ch)) {
161			(void)NULL;
162		} else if (periodchar(pch)) {
163			if (!borderchar(ch))
164				return (0);
165		} else if (periodchar(nch) || nch == '\0') {
166			if (!borderchar(ch))
167				return (0);
168		} else {
169			if (!middlechar(ch))
170				return (0);
171		}
172		pch = ch, ch = nch;
173	}
174	return (1);
175}
176
177/*%
178 * hostname-like (A, MX, WKS) owners can have "*" as their first label
179 * but must otherwise be as a host name.
180 */
181int
182res_ownok(const char *dn) {
183	if (asterchar(dn[0])) {
184		if (periodchar(dn[1]))
185			return (res_hnok(dn+2));
186		if (dn[1] == '\0')
187			return (1);
188	}
189	return (res_hnok(dn));
190}
191
192/*%
193 * SOA RNAMEs and RP RNAMEs can have any printable character in their first
194 * label, but the rest of the name has to look like a host name.
195 */
196int
197res_mailok(const char *dn) {
198	int ch, escaped = 0;
199
200	/* "." is a valid missing representation */
201	if (*dn == '\0')
202		return (1);
203
204	/* otherwise <label>.<hostname> */
205	while ((ch = *dn++) != '\0') {
206		if (!domainchar(ch))
207			return (0);
208		if (!escaped && periodchar(ch))
209			break;
210		if (escaped)
211			escaped = 0;
212		else if (bslashchar(ch))
213			escaped = 1;
214	}
215	if (periodchar(ch))
216		return (res_hnok(dn));
217	return (0);
218}
219
220/*%
221 * This function is quite liberal, since RFC1034's character sets are only
222 * recommendations.
223 */
224int
225res_dnok(const char *dn) {
226	int ch;
227
228	while ((ch = *dn++) != '\0')
229		if (!domainchar(ch))
230			return (0);
231	return (1);
232}
233
234#ifdef BIND_4_COMPAT
235/*%
236 * This module must export the following externally-visible symbols:
237 *	___putlong
238 *	___putshort
239 *	__getlong
240 *	__getshort
241 * Note that one _ comes from C and the others come from us.
242 */
243
244#ifdef SOLARIS2
245#ifdef  __putlong
246#undef  __putlong
247#endif
248#ifdef  __putshort
249#undef  __putshort
250#endif
251#pragma weak    putlong         =       __putlong
252#pragma weak    putshort        =       __putshort
253#endif /* SOLARIS2 */
254
255void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
256void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
257#ifndef __ultrix__
258u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
259u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
260#endif /*__ultrix__*/
261#endif /*BIND_4_COMPAT*/
262
263/*
264 * Weak aliases for applications that use certain private entry points,
265 * and fail to include <resolv.h>.
266 */
267#undef dn_comp
268__weak_reference(__dn_comp, dn_comp);
269#undef dn_expand
270__weak_reference(__dn_expand, dn_expand);
271
272/*! \file */
273