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138 lines
3.9 KiB
C
138 lines
3.9 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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#ifndef lint
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static const char rcsid[] =
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"@(#) $Id: findsaddr-linux.c,v 1.1 2000/11/23 20:17:12 leres Exp $ (LBL)";
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#endif
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/* XXX linux is different (as usual) */
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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 <netinet/in.h>
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#include <arpa/inet.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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#include "ifaddrlist.h"
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#include "traceroute.h"
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static const char route[] = "/proc/net/route";
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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 int i, n;
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register FILE *f;
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register u_int32_t mask;
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u_int32_t dest, tmask;
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struct ifaddrlist *al;
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char buf[256], tdevice[256], device[256];
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static char errbuf[132];
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if ((f = fopen(route, "r")) == NULL) {
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sprintf(errbuf, "open %s: %.128s", route, strerror(errno));
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return (errbuf);
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}
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/* Find the appropriate interface */
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n = 0;
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mask = 0;
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device[0] = '\0';
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while (fgets(buf, sizeof(buf), f) != NULL) {
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++n;
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if (n == 1 && strncmp(buf, "Iface", 5) == 0)
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continue;
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if ((i = sscanf(buf, "%s %x %*s %*s %*s %*s %*s %x",
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tdevice, &dest, &tmask)) != 3)
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return ("junk in buffer");
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if ((to->sin_addr.s_addr & tmask) == dest &&
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(tmask > mask || mask == 0)) {
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mask = tmask;
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strcpy(device, tdevice);
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}
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}
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fclose(f);
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if (device[0] == '\0')
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return ("Can't find interface");
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/* Get the interface address list */
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if ((n = ifaddrlist(&al, errbuf)) < 0)
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return (errbuf);
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if (n == 0)
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return ("Can't find any network interfaces");
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/* Find our appropriate source address */
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for (i = n; i > 0; --i, ++al)
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if (strcmp(device, al->device) == 0)
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break;
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if (i <= 0) {
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sprintf(errbuf, "Can't find interface \"%.32s\"", device);
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return (errbuf);
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}
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setsin(from, al->addr);
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return (NULL);
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}
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