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      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
    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
    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
    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
    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
    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
    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
    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  */
    260 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
    261 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
    262 #ifndef __ultrix__
    263 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
    264 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
    265 #endif /*__ultrix__*/
    266 #endif /*BIND_4_COMPAT*/
    267