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res_comp.cpp
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res_comp.cpp
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/* $NetBSD: res_comp.c,v 1.6 2004/05/22 23:47:09 christos Exp $ */
/*
* Copyright (c) 1985, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "res_comp.h"
#include <arpa/nameser.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
/*
* Expand compressed domain name 'src' to full domain name.
* 'msg' is a pointer to the begining of the message,
* 'eom' points to the first location after the message,
* 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
* Return size of compressed name or -1 if there was an error.
*/
int dn_expand(const uint8_t* msg, const uint8_t* eom, const uint8_t* src, char* dst, int dstsiz) {
int n = ns_name_uncompress(msg, eom, src, dst, (size_t) dstsiz);
if (n > 0 && dst[0] == '.') dst[0] = '\0';
return n;
}
/*
* Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
* Return the size of the compressed name or -1.
* 'length' is the size of the array pointed to by 'comp_dn'.
*/
int dn_comp(const char* src, uint8_t* dst, int dstsiz, uint8_t** dnptrs, uint8_t** lastdnptr) {
return (ns_name_compress(src, dst, (size_t)dstsiz, (const uint8_t**)dnptrs,
(const uint8_t**)lastdnptr));
}
/*
* Skip over a compressed domain name. Return the size or -1.
*/
int dn_skipname(const uint8_t* ptr, const uint8_t* eom) {
const uint8_t* saveptr = ptr;
if (ns_name_skip(&ptr, eom) == -1) return (-1);
return (ptr - saveptr);
}
/*
* Verify that a domain name uses an acceptable character set.
*/
/*
* Note the conspicuous absence of ctype macros in these definitions. On
* non-ASCII hosts, we can't depend on string literals or ctype macros to
* tell us anything about network-format data. The rest of the BIND system
* is not careful about this, but for some reason, we're doing it right here.
*/
/* BIONIC: We also accept underscores in the middle of labels.
* This extension is needed to make resolution on some VPN networks
* work properly.
*/
#define PERIOD 0x2e
#define hyphenchar(c) ((c) == 0x2d)
#define bslashchar(c) ((c) == 0x5c)
#define periodchar(c) ((c) == PERIOD)
#define asterchar(c) ((c) == 0x2a)
#define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) || ((c) >= 0x61 && (c) <= 0x7a))
#define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
#define underscorechar(c) ((c) == 0x5f)
#define borderchar(c) (alphachar(c) || digitchar(c))
#define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
#define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
bool res_hnok(const char* dn) {
char pch = PERIOD, ch = *dn++;
while (ch != '\0') {
char nch = *dn++;
if (periodchar(ch)) {
;
} else if (periodchar(pch) || periodchar(nch) || nch == '\0') {
if (!borderchar(ch)) return false;
} else {
if (!middlechar(ch)) return false;
}
pch = ch, ch = nch;
}
return true;
}
/*
* This function is quite liberal, since RFC 1034's character sets are only
* recommendations.
*/
bool res_dnok(const char* dn) {
char ch;
while ((ch = *dn++) != '\0')
if (!domainchar(ch)) return false;
return true;
}