3773d35eb9
More precisely, this accepts domain labels with an underscore in the middle (i.e. not at the start or the end of the label). This is needed to perform complex CNAME chain resolution in certain VPN networks.
266 lines
8.5 KiB
C
266 lines
8.5 KiB
C
/* $NetBSD: res_comp.c,v 1.6 2004/05/22 23:47:09 christos Exp $ */
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/*
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* Copyright (c) 1985, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Portions Copyright (c) 1993 by Digital Equipment Corporation.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies, and that
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* the name of Digital Equipment Corporation not be used in advertising or
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* publicity pertaining to distribution of the document or software without
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* specific, written prior permission.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
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* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
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* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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/*
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* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
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* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#ifdef notdef
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static const char sccsid[] = "@(#)res_comp.c 8.1 (Berkeley) 6/4/93";
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static const char rcsid[] = "Id: res_comp.c,v 1.1.2.1.4.1 2004/03/09 08:33:54 marka Exp";
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#else
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__RCSID("$NetBSD: res_comp.c,v 1.6 2004/05/22 23:47:09 christos Exp $");
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#endif
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#endif /* LIBC_SCCS and not lint */
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#include <sys/types.h>
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#include <sys/param.h>
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#include <netinet/in.h>
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#include "arpa_nameser.h"
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#include <ctype.h>
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#ifdef ANDROID_CHANGES
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#include "resolv_private.h"
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#else
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#include <resolv.h>
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#endif
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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/*
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* Expand compressed domain name 'src' to full domain name.
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* 'msg' is a pointer to the begining of the message,
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* 'eom' points to the first location after the message,
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* 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
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* Return size of compressed name or -1 if there was an error.
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*/
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int
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dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
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char *dst, int dstsiz)
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{
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int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
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if (n > 0 && dst[0] == '.')
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dst[0] = '\0';
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return (n);
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}
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/*
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* Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
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* Return the size of the compressed name or -1.
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* 'length' is the size of the array pointed to by 'comp_dn'.
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*/
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int
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dn_comp(const char *src, u_char *dst, int dstsiz,
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u_char **dnptrs, u_char **lastdnptr)
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{
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return (ns_name_compress(src, dst, (size_t)dstsiz,
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(const u_char **)dnptrs,
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(const u_char **)lastdnptr));
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}
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/*
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* Skip over a compressed domain name. Return the size or -1.
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*/
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int
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dn_skipname(const u_char *ptr, const u_char *eom) {
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const u_char *saveptr = ptr;
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if (ns_name_skip(&ptr, eom) == -1)
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return (-1);
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return (ptr - saveptr);
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}
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/*
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* Verify that a domain name uses an acceptable character set.
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*/
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/*
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* Note the conspicuous absence of ctype macros in these definitions. On
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* non-ASCII hosts, we can't depend on string literals or ctype macros to
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* tell us anything about network-format data. The rest of the BIND system
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* is not careful about this, but for some reason, we're doing it right here.
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*/
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/* BIONIC: We also accept underscores in the middle of labels.
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* This extension is needed to make resolution on some VPN networks
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* work properly.
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*/
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#define PERIOD 0x2e
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#define hyphenchar(c) ((c) == 0x2d)
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#define bslashchar(c) ((c) == 0x5c)
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#define periodchar(c) ((c) == PERIOD)
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#define asterchar(c) ((c) == 0x2a)
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#define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
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|| ((c) >= 0x61 && (c) <= 0x7a))
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#define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
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#define underscorechar(c) ((c) == 0x5f)
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#define borderchar(c) (alphachar(c) || digitchar(c))
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#define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
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#define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
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int
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res_hnok(const char *dn) {
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int pch = PERIOD, ch = *dn++;
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while (ch != '\0') {
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int nch = *dn++;
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if (periodchar(ch)) {
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;
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} else if (periodchar(pch)) {
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if (!borderchar(ch))
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return (0);
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} else if (periodchar(nch) || nch == '\0') {
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if (!borderchar(ch))
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return (0);
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} else {
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if (!middlechar(ch))
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return (0);
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}
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pch = ch, ch = nch;
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}
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return (1);
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}
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/*
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* hostname-like (A, MX, WKS) owners can have "*" as their first label
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* but must otherwise be as a host name.
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*/
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int
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res_ownok(const char *dn) {
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if (asterchar(dn[0])) {
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if (periodchar(dn[1]))
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return (res_hnok(dn+2));
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if (dn[1] == '\0')
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return (1);
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}
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return (res_hnok(dn));
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}
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/*
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* SOA RNAMEs and RP RNAMEs can have any printable character in their first
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* label, but the rest of the name has to look like a host name.
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*/
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int
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res_mailok(const char *dn) {
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int ch, escaped = 0;
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/* "." is a valid missing representation */
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if (*dn == '\0')
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return (1);
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/* otherwise <label>.<hostname> */
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while ((ch = *dn++) != '\0') {
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if (!domainchar(ch))
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return (0);
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if (!escaped && periodchar(ch))
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break;
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if (escaped)
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escaped = 0;
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else if (bslashchar(ch))
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escaped = 1;
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}
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if (periodchar(ch))
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return (res_hnok(dn));
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return (0);
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}
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/*
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* This function is quite liberal, since RFC 1034's character sets are only
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* recommendations.
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*/
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int
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res_dnok(const char *dn) {
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int ch;
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while ((ch = *dn++) != '\0')
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if (!domainchar(ch))
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return (0);
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return (1);
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}
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#ifdef BIND_4_COMPAT
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/*
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* This module must export the following externally-visible symbols:
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* ___putlong
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* ___putshort
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* __getlong
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* __getshort
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* Note that one _ comes from C and the others come from us.
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*/
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void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
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void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
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#ifndef __ultrix__
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u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
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u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
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#endif /*__ultrix__*/
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#endif /*BIND_4_COMPAT*/
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