• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 <arpa/nameser.h>
74 #include <ctype.h>
75 #include <netinet/in.h>
76 #include <sys/param.h>
77 #include <sys/types.h>
78 #include <stdio.h>
79 #include <string.h>
80 #include <unistd.h>
81 
82 #include "resolv_private.h"
83 
84 /*
85  * Expand compressed domain name 'src' to full domain name.
86  * 'msg' is a pointer to the begining of the message,
87  * 'eom' points to the first location after the message,
88  * 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
89  * Return size of compressed name or -1 if there was an error.
90  */
dn_expand(const u_char * msg,const u_char * eom,const u_char * src,char * dst,int dstsiz)91 int dn_expand(const u_char* msg, const u_char* eom, const u_char* src, char* dst, int dstsiz) {
92     int n = ns_name_uncompress(msg, eom, src, dst, (size_t) dstsiz);
93 
94     if (n > 0 && dst[0] == '.') dst[0] = '\0';
95     return (n);
96 }
97 
98 /*
99  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
100  * Return the size of the compressed name or -1.
101  * 'length' is the size of the array pointed to by 'comp_dn'.
102  */
dn_comp(const char * src,u_char * dst,int dstsiz,u_char ** dnptrs,u_char ** lastdnptr)103 int dn_comp(const char* src, u_char* dst, int dstsiz, u_char** dnptrs, u_char** lastdnptr) {
104     return (ns_name_compress(src, dst, (size_t) dstsiz, (const u_char**) dnptrs,
105                              (const u_char**) lastdnptr));
106 }
107 
108 /*
109  * Skip over a compressed domain name. Return the size or -1.
110  */
dn_skipname(const u_char * ptr,const u_char * eom)111 int dn_skipname(const u_char* ptr, const u_char* eom) {
112     const u_char* saveptr = ptr;
113 
114     if (ns_name_skip(&ptr, eom) == -1) return (-1);
115     return (ptr - saveptr);
116 }
117 
118 /*
119  * Verify that a domain name uses an acceptable character set.
120  */
121 
122 /*
123  * Note the conspicuous absence of ctype macros in these definitions.  On
124  * non-ASCII hosts, we can't depend on string literals or ctype macros to
125  * tell us anything about network-format data.  The rest of the BIND system
126  * is not careful about this, but for some reason, we're doing it right here.
127  */
128 
129 /* BIONIC: We also accept underscores in the middle of labels.
130  *         This extension is needed to make resolution on some VPN networks
131  *         work properly.
132  */
133 
134 #define PERIOD 0x2e
135 #define hyphenchar(c) ((c) == 0x2d)
136 #define bslashchar(c) ((c) == 0x5c)
137 #define periodchar(c) ((c) == PERIOD)
138 #define asterchar(c) ((c) == 0x2a)
139 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) || ((c) >= 0x61 && (c) <= 0x7a))
140 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
141 #define underscorechar(c) ((c) == 0x5f)
142 
143 #define borderchar(c) (alphachar(c) || digitchar(c))
144 #define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
145 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
146 
res_hnok(const char * dn)147 int res_hnok(const char* dn) {
148     int pch = PERIOD, ch = *dn++;
149 
150     while (ch != '\0') {
151         int nch = *dn++;
152 
153         if (periodchar(ch)) {
154             ;
155         } else if (periodchar(pch)) {
156             if (!borderchar(ch)) return (0);
157         } else if (periodchar(nch) || nch == '\0') {
158             if (!borderchar(ch)) return (0);
159         } else {
160             if (!middlechar(ch)) return (0);
161         }
162         pch = ch, ch = nch;
163     }
164     return (1);
165 }
166 
167 /*
168  * hostname-like (A, MX, WKS) owners can have "*" as their first label
169  * but must otherwise be as a host name.
170  */
res_ownok(const char * dn)171 int res_ownok(const char* dn) {
172     if (asterchar(dn[0])) {
173         if (periodchar(dn[1])) return (res_hnok(dn + 2));
174         if (dn[1] == '\0') return (1);
175     }
176     return (res_hnok(dn));
177 }
178 
179 /*
180  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
181  * label, but the rest of the name has to look like a host name.
182  */
res_mailok(const char * dn)183 int res_mailok(const char* dn) {
184     int ch, escaped = 0;
185 
186     /* "." is a valid missing representation */
187     if (*dn == '\0') return (1);
188 
189     /* otherwise <label>.<hostname> */
190     while ((ch = *dn++) != '\0') {
191         if (!domainchar(ch)) return (0);
192         if (!escaped && periodchar(ch)) break;
193         if (escaped)
194             escaped = 0;
195         else if (bslashchar(ch))
196             escaped = 1;
197     }
198     if (periodchar(ch)) return (res_hnok(dn));
199     return (0);
200 }
201 
202 /*
203  * This function is quite liberal, since RFC 1034's character sets are only
204  * recommendations.
205  */
res_dnok(const char * dn)206 int res_dnok(const char* dn) {
207     int ch;
208 
209     while ((ch = *dn++) != '\0')
210         if (!domainchar(ch)) return (0);
211     return (1);
212 }
213