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 #include <sys/cdefs.h>
73 #if defined(LIBC_SCCS) && !defined(lint)
74 #ifdef notdef
75 static const char sccsid[] = "@(#)res_comp.c 8.1 (Berkeley) 6/4/93";
76 static const char rcsid[] = "Id: res_comp.c,v 1.1.2.1.4.1 2004/03/09 08:33:54 marka Exp";
77 #else
78 __RCSID("$NetBSD: res_comp.c,v 1.6 2004/05/22 23:47:09 christos Exp $");
79 #endif
80 #endif /* LIBC_SCCS and not lint */
81
82 #include <sys/types.h>
83 #include <sys/param.h>
84 #include <netinet/in.h>
85 #include <arpa/nameser.h>
86 #include <ctype.h>
87 #ifdef ANDROID_CHANGES
88 #include "resolv_private.h"
89 #else
90 #include <resolv.h>
91 #endif
92 #include <stdio.h>
93 #include <string.h>
94 #include <unistd.h>
95
96 /*
97 * Expand compressed domain name 'src' to full domain name.
98 * 'msg' is a pointer to the begining of the message,
99 * 'eom' points to the first location after the message,
100 * 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
101 * Return size of compressed name or -1 if there was an error.
102 */
103 int
dn_expand(const u_char * msg,const u_char * eom,const u_char * src,char * dst,int dstsiz)104 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
105 char *dst, int dstsiz)
106 {
107 int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
108
109 if (n > 0 && dst[0] == '.')
110 dst[0] = '\0';
111 return (n);
112 }
113
114 /*
115 * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
116 * Return the size of the compressed name or -1.
117 * 'length' is the size of the array pointed to by 'comp_dn'.
118 */
119 int
dn_comp(const char * src,u_char * dst,int dstsiz,u_char ** dnptrs,u_char ** lastdnptr)120 dn_comp(const char *src, u_char *dst, int dstsiz,
121 u_char **dnptrs, u_char **lastdnptr)
122 {
123 return (ns_name_compress(src, dst, (size_t)dstsiz,
124 (const u_char **)dnptrs,
125 (const u_char **)lastdnptr));
126 }
127
128 /*
129 * Skip over a compressed domain name. Return the size or -1.
130 */
131 int
dn_skipname(const u_char * ptr,const u_char * eom)132 dn_skipname(const u_char *ptr, const u_char *eom) {
133 const u_char *saveptr = ptr;
134
135 if (ns_name_skip(&ptr, eom) == -1)
136 return (-1);
137 return (ptr - saveptr);
138 }
139
140 /*
141 * Verify that a domain name uses an acceptable character set.
142 */
143
144 /*
145 * Note the conspicuous absence of ctype macros in these definitions. On
146 * non-ASCII hosts, we can't depend on string literals or ctype macros to
147 * tell us anything about network-format data. The rest of the BIND system
148 * is not careful about this, but for some reason, we're doing it right here.
149 */
150
151 /* BIONIC: We also accept underscores in the middle of labels.
152 * This extension is needed to make resolution on some VPN networks
153 * work properly.
154 */
155
156 #define PERIOD 0x2e
157 #define hyphenchar(c) ((c) == 0x2d)
158 #define bslashchar(c) ((c) == 0x5c)
159 #define periodchar(c) ((c) == PERIOD)
160 #define asterchar(c) ((c) == 0x2a)
161 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
162 || ((c) >= 0x61 && (c) <= 0x7a))
163 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
164 #define underscorechar(c) ((c) == 0x5f)
165
166 #define borderchar(c) (alphachar(c) || digitchar(c))
167 #define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
168 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
169
170 int
res_hnok(const char * dn)171 res_hnok(const char *dn) {
172 int pch = PERIOD, ch = *dn++;
173
174 while (ch != '\0') {
175 int nch = *dn++;
176
177 if (periodchar(ch)) {
178 ;
179 } else if (periodchar(pch)) {
180 if (!borderchar(ch))
181 return (0);
182 } else if (periodchar(nch) || nch == '\0') {
183 if (!borderchar(ch))
184 return (0);
185 } else {
186 if (!middlechar(ch))
187 return (0);
188 }
189 pch = ch, ch = nch;
190 }
191 return (1);
192 }
193
194 /*
195 * hostname-like (A, MX, WKS) owners can have "*" as their first label
196 * but must otherwise be as a host name.
197 */
198 int
res_ownok(const char * dn)199 res_ownok(const char *dn) {
200 if (asterchar(dn[0])) {
201 if (periodchar(dn[1]))
202 return (res_hnok(dn+2));
203 if (dn[1] == '\0')
204 return (1);
205 }
206 return (res_hnok(dn));
207 }
208
209 /*
210 * SOA RNAMEs and RP RNAMEs can have any printable character in their first
211 * label, but the rest of the name has to look like a host name.
212 */
213 int
res_mailok(const char * dn)214 res_mailok(const char *dn) {
215 int ch, escaped = 0;
216
217 /* "." is a valid missing representation */
218 if (*dn == '\0')
219 return (1);
220
221 /* otherwise <label>.<hostname> */
222 while ((ch = *dn++) != '\0') {
223 if (!domainchar(ch))
224 return (0);
225 if (!escaped && periodchar(ch))
226 break;
227 if (escaped)
228 escaped = 0;
229 else if (bslashchar(ch))
230 escaped = 1;
231 }
232 if (periodchar(ch))
233 return (res_hnok(dn));
234 return (0);
235 }
236
237 /*
238 * This function is quite liberal, since RFC 1034's character sets are only
239 * recommendations.
240 */
241 int
res_dnok(const char * dn)242 res_dnok(const char *dn) {
243 int ch;
244
245 while ((ch = *dn++) != '\0')
246 if (!domainchar(ch))
247 return (0);
248 return (1);
249 }
250
251 #ifdef BIND_4_COMPAT
252 /*
253 * This module must export the following externally-visible symbols:
254 * ___putlong
255 * ___putshort
256 * __getlong
257 * __getshort
258 * Note that one _ comes from C and the others come from us.
259 */
__putlong(u_int32_t src,u_char * dst)260 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
__putshort(u_int16_t src,u_char * dst)261 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
262 #ifndef __ultrix__
_getlong(const u_char * src)263 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
_getshort(const u_char * src)264 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
265 #endif /*__ultrix__*/
266 #endif /*BIND_4_COMPAT*/
267