1 /* $NetBSD: res_comp.c,v 1.6 2004/05/22 23:47:09 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. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 /*
37 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
38 *
39 * Permission to use, copy, modify, and distribute this software for any
40 * purpose with or without fee is hereby granted, provided that the above
41 * copyright notice and this permission notice appear in all copies, and that
42 * the name of Digital Equipment Corporation not be used in advertising or
43 * publicity pertaining to distribution of the document or software without
44 * specific, written prior permission.
45 *
46 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
47 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
48 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
49 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
50 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
51 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
52 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
53 * SOFTWARE.
54 */
55
56 /*
57 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
58 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
59 *
60 * Permission to use, copy, modify, and distribute this software for any
61 * purpose with or without fee is hereby granted, provided that the above
62 * copyright notice and this permission notice appear in all copies.
63 *
64 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
65 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
66 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
67 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
68 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
69 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
70 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
71 */
72
73 #include "res_comp.h"
74
75 #include <arpa/nameser.h>
76 #include <netinet/in.h>
77 #include <string.h>
78 #include <unistd.h>
79
80 /*
81 * Expand compressed domain name 'src' to full domain name.
82 * 'msg' is a pointer to the begining of the message,
83 * 'eom' points to the first location after the message,
84 * 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
85 * Return size of compressed name or -1 if there was an error.
86 */
dn_expand(const uint8_t * msg,const uint8_t * eom,const uint8_t * src,char * dst,int dstsiz)87 int dn_expand(const uint8_t* msg, const uint8_t* eom, const uint8_t* src, char* dst, int dstsiz) {
88 int n = ns_name_uncompress(msg, eom, src, dst, (size_t) dstsiz);
89
90 if (n > 0 && dst[0] == '.') dst[0] = '\0';
91 return n;
92 }
93
94 /*
95 * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
96 * Return the size of the compressed name or -1.
97 * 'length' is the size of the array pointed to by 'comp_dn'.
98 */
dn_comp(const char * src,uint8_t * dst,int dstsiz,uint8_t ** dnptrs,uint8_t ** lastdnptr)99 int dn_comp(const char* src, uint8_t* dst, int dstsiz, uint8_t** dnptrs, uint8_t** lastdnptr) {
100 return (ns_name_compress(src, dst, (size_t)dstsiz, (const uint8_t**)dnptrs,
101 (const uint8_t**)lastdnptr));
102 }
103
104 /*
105 * Skip over a compressed domain name. Return the size or -1.
106 */
dn_skipname(const uint8_t * ptr,const uint8_t * eom)107 int dn_skipname(const uint8_t* ptr, const uint8_t* eom) {
108 const uint8_t* saveptr = ptr;
109
110 if (ns_name_skip(&ptr, eom) == -1) return (-1);
111 return (ptr - saveptr);
112 }
113
114 /*
115 * Verify that a domain name uses an acceptable character set.
116 */
117
118 /*
119 * Note the conspicuous absence of ctype macros in these definitions. On
120 * non-ASCII hosts, we can't depend on string literals or ctype macros to
121 * tell us anything about network-format data. The rest of the BIND system
122 * is not careful about this, but for some reason, we're doing it right here.
123 */
124
125 /* BIONIC: We also accept underscores in the middle of labels.
126 * This extension is needed to make resolution on some VPN networks
127 * work properly.
128 */
129
130 #define PERIOD 0x2e
131 #define hyphenchar(c) ((c) == 0x2d)
132 #define bslashchar(c) ((c) == 0x5c)
133 #define periodchar(c) ((c) == PERIOD)
134 #define asterchar(c) ((c) == 0x2a)
135 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) || ((c) >= 0x61 && (c) <= 0x7a))
136 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
137 #define underscorechar(c) ((c) == 0x5f)
138
139 #define borderchar(c) (alphachar(c) || digitchar(c))
140 #define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
141 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
142
res_hnok(const char * dn)143 bool res_hnok(const char* dn) {
144 int pch = PERIOD, ch = *dn++;
145
146 while (ch != '\0') {
147 int nch = *dn++;
148
149 if (periodchar(ch)) {
150 ;
151 } else if (periodchar(pch) || periodchar(nch) || nch == '\0') {
152 if (!borderchar(ch)) return false;
153 } else {
154 if (!middlechar(ch)) return false;
155 }
156 pch = ch, ch = nch;
157 }
158 return true;
159 }
160
161 /*
162 * This function is quite liberal, since RFC 1034's character sets are only
163 * recommendations.
164 */
res_dnok(const char * dn)165 bool res_dnok(const char* dn) {
166 int ch;
167
168 while ((ch = *dn++) != '\0')
169 if (!domainchar(ch)) return false;
170 return true;
171 }
172