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/*
* Copyright (c) 2000
* 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 Computer Systems
* Engineering Group at Lawrence Berkeley Laboratory.
* 4. Neither the name of the University nor of the Laboratory 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.
*/
#ifndef lint
static const char rcsid[] =
"@(#) $Id: findsaddr-linux.c,v 1.1 2000/11/23 20:17:12 leres Exp $ (LBL)";
#endif
/* XXX linux is different (as usual) */
#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif
#include <sys/time.h> /* concession to AIX */
#if __STDC__
struct mbuf;
struct rtentry;
#endif
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "gnuc.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#include "findsaddr.h"
#include "ifaddrlist.h"
#include "traceroute.h"
static const char route[] = "/proc/net/route";
/*
* Return the source address for the given destination address
*/
const char *
findsaddr(register const struct sockaddr_in *to,
register struct sockaddr_in *from)
{
register int i, n;
register FILE *f;
register u_int32_t mask;
u_int32_t dest, tmask;
struct ifaddrlist *al;
char buf[256], tdevice[256], device[256];
static char errbuf[132];
if ((f = fopen(route, "r")) == NULL) {
sprintf(errbuf, "open %s: %.128s", route, strerror(errno));
return (errbuf);
}
/* Find the appropriate interface */
n = 0;
mask = 0;
device[0] = '\0';
while (fgets(buf, sizeof(buf), f) != NULL) {
++n;
if (n == 1 && strncmp(buf, "Iface", 5) == 0)
continue;
if ((i = sscanf(buf, "%s %x %*s %*s %*s %*s %*s %x",
tdevice, &dest, &tmask)) != 3)
return ("junk in buffer");
if ((to->sin_addr.s_addr & tmask) == dest &&
(tmask > mask || mask == 0)) {
mask = tmask;
strcpy(device, tdevice);
}
}
fclose(f);
if (device[0] == '\0')
return ("Can't find interface");
/* Get the interface address list */
if ((n = ifaddrlist(&al, errbuf)) < 0)
return (errbuf);
if (n == 0)
return ("Can't find any network interfaces");
/* Find our appropriate source address */
for (i = n; i > 0; --i, ++al)
if (strcmp(device, al->device) == 0)
break;
if (i <= 0) {
sprintf(errbuf, "Can't find interface \"%.32s\"", device);
return (errbuf);
}
setsin(from, al->addr);
return (NULL);
}
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