411 lines
13 KiB
C
411 lines
13 KiB
C
#if !defined(lint) && !defined(SABER)
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static const char sccsid[] = "@(#)ns_sort.c 4.10 (Berkeley) 3/3/91";
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static const char rcsid[] = "$Id: ns_sort.c,v 8.6 2000/04/21 06:54:13 vixie Exp $";
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#endif /* not lint */
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/*
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* Copyright (c) 1986, 1990
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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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* Portions Copyright (c) 1996-2000 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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* CONSORTIUM 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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* Sorting should really be handled by the resolver, but:
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* 1) There are too many brain dead resolvers out there that can't be replaced.
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* 2) It would be a pain to individually configure all those resolvers anyway.
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*
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* Here's the scoop:
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*
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* To enable address sorting in responses, you need to supply the sortlist
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* statement in the config file. The sortlist statement takes an
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* address match list and interprets it even more specially than the
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* topology statement does.
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*
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* Each top level statement in the sortlist must itself be an explicit
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* address match list with one or two elements. The first element
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* (which may be an IP address, an IP prefix, an ACL name or nested
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* address match list) of each top level list is checked against the
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* source address of the query until a match is found.
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*
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* Once the source address of the query has been matched, if the top level
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* statement contains only one element, the actual primitive element that
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* matched the source address is used to select the address in the response
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* to move to the beginning of the response. If the statement is a list
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* of two elements, then the second element is treated like the address
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* match list in a topology statement. Each top level element is assigned
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* a distance and the address in the response with the minimum distance is
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* moved to the beginning of the response.
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*
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* In the following example, any queries received from any of the addresses
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* of the host itself will get responses preferring addresses on any of
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* the locally connected networks. Next most preferred are addresses on
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* the 192.168.1/24 network, and after that either the 192.168.2/24 or
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* 192.168.3/24 network with no preference shown between these two networks.
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* Queries received from a host on the 192.168.1/24 network will prefer
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* other addresses on that network to the 192.168.2/24 and 192.168.3/24
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* networks. Queries received from a host on the 192.168.4/24 or the
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* 192.168.5/24 network will only prefer other addresses on their
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* directly connected networks.
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*
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* sortlist {
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* {
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* localhost;
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* {
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* localnets;
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* 192.168.1/24;
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* { 192,168.2/24; 192.168.3/24; };
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* };
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* };
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* {
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* 192.168.1/24;
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* {
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* 192.168.1/24;
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* { 192.168.2/24; 192.168.3/24; };
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* };
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* };
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* {
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* 192.168.2/24;
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* {
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* 192.168.2/24;
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* { 192.168.1/24; 192.168.3/24; };
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* };
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* };
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* {
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* 192.168.3/24;
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* {
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* 192.168.3/24;
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* { 192.168.1/24; 192.168.2/24; };
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* };
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* };
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* {
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* { 192.168.4/24; 192.168.5/24; };
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* };
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* };
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*
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*
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* The following example will give reasonable behaviour for the local host
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* and hosts on directly connected networks. It is similar to the behavior
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* of the address sort in BIND 4.9.x. Responses sent to queries from the
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* local host will favor any of the directly connected networks. Responses
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* sent to queries from any other hosts on a directly connected network will
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* prefer addresses on that same network. Responses to other queries will
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* not be sorted.
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*
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* sortlist {
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* { localhost; localnets; };
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* { localnets; };
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* };
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*
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* XXX - it wouldb e nice to have an ACL called "source" that matched the
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* source address of a query so that a host could be configured to
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* automatically prefer itself, and an ACL called "sourcenet", that
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* would return the primitive IP match element that matched the source
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* address so that you could do:
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* { localnets; { sourcenet; { other stuff ...}; };
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* and automatically get similar behaviour to what you get with:
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* { localnets; };
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*
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*/
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#include "port_before.h"
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/file.h>
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#include <netinet/in.h>
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#include <arpa/nameser.h>
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#include <arpa/inet.h>
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#include <stdio.h>
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#include <syslog.h>
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#include <resolv.h>
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#include <isc/eventlib.h>
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#include <isc/logging.h>
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#include "port_after.h"
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#include "named.h"
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static int sort_rr(u_char *cp, u_char *eom, int ancount, ip_match_list iml);
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static int ip_match_address_elt(ip_match_list, struct in_addr,
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ip_match_element *);
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void
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sort_response(u_char *cp, u_char *eom, int ancount, struct sockaddr_in *from) {
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struct in_addr address;
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struct ip_match_element imelement;
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ip_match_element imetl, imematch, imeprimitive;
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struct ip_match_list imlist;
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ip_match_list iml;
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int indirect, matched;
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if (server_options->sortlist == NULL)
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return;
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if (from->sin_family != AF_INET)
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return;
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address = from->sin_addr;
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for (imetl = server_options->sortlist->first; imetl != NULL;
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imetl = imetl->next) {
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if (imetl->type == ip_match_indirect)
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imematch = imetl->u.indirect.list->first;
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else
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/*
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* allow a bare pattern as a top level statement
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* and treat it like {pattern;};
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*/
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imematch = imetl;
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switch (imematch->type) {
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case ip_match_pattern:
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indirect = 0;
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break;
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case ip_match_indirect:
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indirect = 1;
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break;
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case ip_match_localhost:
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imematch->u.indirect.list = local_addresses;
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indirect = 1;
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break;
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case ip_match_localnets:
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imematch->u.indirect.list = local_networks;
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indirect = 1;
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break;
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default:
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panic("unexpected ime type in ip_match_address()",
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NULL);
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}
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if (indirect) {
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imeprimitive = NULL;
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matched = ip_match_address_elt(imematch->u.indirect.list,
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address, &imeprimitive);
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if (matched >= 0) {
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if (imematch->flags & IP_MATCH_NEGATE)
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/* Don't sort */
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return;
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} else
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continue;
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} else {
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if (ina_onnet(address, imematch->u.direct.address,
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imematch->u.direct.mask)) {
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if (imematch->flags & IP_MATCH_NEGATE)
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/* Don't sort */
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return;
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else
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imeprimitive = imematch;
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} else
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continue;
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}
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if (imetl != imematch && imematch->next != NULL) {
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/*
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* Not a bare pattern at the top level, but a two
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* element list
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*/
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switch (imematch->next->type) {
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case ip_match_pattern:
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case ip_match_localhost:
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case ip_match_localnets:
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imelement = *(imematch->next);
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imelement.next = NULL;
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iml = &imlist;
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iml->first = iml->last = &imelement;
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break;
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case ip_match_indirect:
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iml = imematch->next->u.indirect.list;
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break;
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default:
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panic("unexpected ime type in ip_match_address()",
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NULL);
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}
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} else if (imeprimitive) {
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imelement = *imeprimitive;
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imelement.next = NULL;
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iml = &imlist;
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iml->first = iml->last = &imelement;
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} else {
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/* Don't sort because we'd just use "any" */
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return;
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}
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sort_rr(cp, eom, ancount, iml);
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break;
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}
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return;
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}
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static int
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sort_rr(u_char *cp, u_char *eom, int ancount, ip_match_list iml) {
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int type, class, dlen, n, c, distance, closest;
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struct in_addr inaddr;
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u_char *rr1 = NULL, *rrbest, *cpstart;
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rr1 = NULL;
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cpstart = cp;
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for (c = ancount; c > 0; --c) {
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n = dn_skipname(cp, eom);
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if (n < 0)
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return (1); /* bogus, stop processing */
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cp += n;
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if (cp + QFIXEDSZ > eom)
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return (1);
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GETSHORT(type, cp);
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GETSHORT(class, cp);
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cp += INT32SZ;
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GETSHORT(dlen, cp);
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if (dlen > eom - cp)
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return (1); /* bogus, stop processing */
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switch (type) {
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case T_A:
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switch (class) {
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case C_IN:
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case C_HS:
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memcpy((char *)&inaddr, cp, INADDRSZ);
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/* Find the address with the minimum distance */
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if (rr1 == NULL) {
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rr1 = cp;
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rrbest = cp;
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closest = distance_of_address(iml, inaddr);
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} else {
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distance = distance_of_address(iml, inaddr);
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if (distance < closest) {
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rrbest = cp;
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closest = distance;
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}
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}
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break;
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}
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break;
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}
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cp += dlen;
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}
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if (rr1 != rrbest && rr1 != NULL) {
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memcpy((char *)&inaddr, rrbest, INADDRSZ);
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memcpy(rrbest, rr1, INADDRSZ);
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memcpy(rr1, (char *)&inaddr, INADDRSZ);
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}
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return (0);
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}
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/*
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* Just like ip_match_address(), but also returns a pointer to the primitive
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* element that matched.
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*/
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static int
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ip_match_address_elt(ip_match_list iml, struct in_addr address,
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ip_match_element *imep) {
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ip_match_element ime;
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int ret;
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int indirect;
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INSIST(iml != NULL);
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for (ime = iml->first; ime != NULL; ime = ime->next) {
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switch (ime->type) {
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case ip_match_pattern:
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indirect = 0;
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break;
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case ip_match_indirect:
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indirect = 1;
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break;
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case ip_match_localhost:
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ime->u.indirect.list = local_addresses;
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indirect = 1;
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break;
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case ip_match_localnets:
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ime->u.indirect.list = local_networks;
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indirect = 1;
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break;
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default:
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panic("unexpected ime type in ip_match_address()",
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NULL);
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}
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if (indirect) {
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ret = ip_match_address_elt(ime->u.indirect.list,
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address, imep);
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if (ret >= 0) {
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if (ime->flags & IP_MATCH_NEGATE)
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ret = (ret) ? 0 : 1;
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return (ret);
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}
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} else {
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if (ina_onnet(address, ime->u.direct.address,
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ime->u.direct.mask)) {
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*imep = ime;
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if (ime->flags & IP_MATCH_NEGATE)
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return (0);
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else
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return (1);
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}
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}
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}
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return (-1);
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}
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