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221 lines
5.3 KiB
C
221 lines
5.3 KiB
C
/*
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* Copyright (c) 2000
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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 Computer Systems
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* Engineering Group at Lawrence Berkeley Laboratory.
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* 4. Neither the name of the University nor of the Laboratory may be used
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* to endorse or promote products derived from this software without
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* 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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* $FreeBSD$
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*/
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/* XXX Yes this is WAY too complicated */
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#ifndef lint
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static const char rcsid[] =
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"@(#) $Id: findsaddr-socket.c,v 1.1 2000/11/23 20:17:12 leres Exp $ (LBL)";
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#endif
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#include <sys/param.h>
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#include <sys/file.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#ifdef HAVE_SYS_SOCKIO_H
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#include <sys/sockio.h>
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#endif
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#include <sys/time.h> /* concession to AIX */
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#if __STDC__
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struct mbuf;
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struct rtentry;
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#endif
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#include <net/if.h>
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#include <net/if_dl.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "gnuc.h"
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#ifdef HAVE_OS_PROTO_H
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#include "os-proto.h"
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#endif
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#include "findsaddr.h"
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#ifdef HAVE_SOCKADDR_SA_LEN
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#define SALEN(sa) ((sa)->sa_len)
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#else
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#define SALEN(sa) salen(sa)
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#endif
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#ifndef roundup
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#define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
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#endif
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struct rtmsg {
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struct rt_msghdr rtmsg;
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u_char data[512];
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};
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static struct rtmsg rtmsg = {
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{ 0, RTM_VERSION, RTM_GET, 0,
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RTF_UP | RTF_GATEWAY | RTF_HOST | RTF_STATIC,
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RTA_DST | RTA_IFA, 0, 0, 0, 0, 0, { 0 } },
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{ 0 }
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};
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#ifndef HAVE_SOCKADDR_SA_LEN
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static int salen(struct sockaddr *);
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#endif
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/*
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* Return the source address for the given destination address
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*/
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const char *
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findsaddr(register const struct sockaddr_in *to,
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register struct sockaddr_in *from)
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{
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register struct rt_msghdr *rp;
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register u_char *cp;
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register struct sockaddr_in *sp, *ifa;
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register struct sockaddr *sa;
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register int s, size, cc, seq, i;
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register pid_t pid;
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static char errbuf[512];
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s = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
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if (s < 0) {
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sprintf(errbuf, "socket: %.128s", strerror(errno));
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return (errbuf);
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}
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seq = 0;
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pid = getpid();
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rp = &rtmsg.rtmsg;
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rp->rtm_seq = ++seq;
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cp = (u_char *)(rp + 1);
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sp = (struct sockaddr_in *)cp;
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*sp = *to;
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cp += roundup(SALEN((struct sockaddr *)sp), sizeof(u_int32_t));
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size = cp - (u_char *)rp;
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rp->rtm_msglen = size;
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cc = write(s, (char *)rp, size);
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if (cc < 0) {
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sprintf(errbuf, "write: %.128s", strerror(errno));
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close(s);
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return (errbuf);
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}
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if (cc != size) {
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sprintf(errbuf, "short write (%d != %d)", cc, size);
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close(s);
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return (errbuf);
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}
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size = sizeof(rtmsg);
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do {
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memset(rp, 0, size);
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cc = read(s, (char *)rp, size);
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if (cc < 0) {
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sprintf(errbuf, "read: %.128s", strerror(errno));
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close(s);
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return (errbuf);
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}
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} while (rp->rtm_seq != seq || rp->rtm_pid != pid);
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close(s);
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if (rp->rtm_version != RTM_VERSION) {
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sprintf(errbuf, "bad version %d", rp->rtm_version);
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return (errbuf);
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}
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if (rp->rtm_msglen > cc) {
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sprintf(errbuf, "bad msglen %d > %d", rp->rtm_msglen, cc);
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return (errbuf);
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}
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if (rp->rtm_errno != 0) {
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sprintf(errbuf, "rtm_errno: %.128s", strerror(rp->rtm_errno));
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return (errbuf);
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}
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/* Find the interface sockaddr */
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cp = (u_char *)(rp + 1);
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for (i = 1; i != 0; i <<= 1)
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if ((i & rp->rtm_addrs) != 0) {
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sa = (struct sockaddr *)cp;
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switch (i) {
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case RTA_IFA:
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if (sa->sa_family == AF_INET) {
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ifa = (struct sockaddr_in *)cp;
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if (ifa->sin_addr.s_addr != 0) {
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*from = *ifa;
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return (NULL);
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}
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}
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break;
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}
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if (SALEN(sa) == 0)
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cp += sizeof(long);
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else
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cp += roundup(SALEN(sa), sizeof(long));
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}
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return ("failed!");
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}
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#ifndef HAVE_SOCKADDR_SA_LEN
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static int
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salen(struct sockaddr *sa)
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{
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switch (sa->sa_family) {
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case AF_INET:
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return (sizeof(struct sockaddr_in));
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case AF_LINK:
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return (sizeof(struct sockaddr_dl));
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default:
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return (sizeof(struct sockaddr));
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}
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}
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#endif
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