of them, such in a system with a large number of VLANs. Submitted by: Nick Rogers MFC after: 2 weeks
876 lines
20 KiB
C
876 lines
20 KiB
C
/*
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* Copyright (c) 1984, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Sun Microsystems, Inc.
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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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* 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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#if 0
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#ifndef lint
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static char const copyright[] =
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"@(#) Copyright (c) 1984, 1993\n\
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The Regents of the University of California. All rights reserved.\n";
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#endif /* not lint */
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#ifndef lint
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static char const sccsid[] = "@(#)from: arp.c 8.2 (Berkeley) 1/2/94";
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#endif /* not lint */
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#endif
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* arp - display, set, and delete arp table entries
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*/
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#include <sys/param.h>
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#include <sys/file.h>
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#include <sys/socket.h>
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#include <sys/sockio.h>
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#include <sys/sysctl.h>
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#include <sys/ioctl.h>
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#include <sys/time.h>
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#include <net/if.h>
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#include <net/if_dl.h>
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#include <net/if_types.h>
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#include <net/route.h>
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#include <net/iso88025.h>
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#include <netinet/in.h>
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#include <netinet/if_ether.h>
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#include <arpa/inet.h>
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#include <ctype.h>
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#include <err.h>
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#include <errno.h>
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#include <netdb.h>
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#include <nlist.h>
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#include <paths.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 <strings.h>
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#include <unistd.h>
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typedef void (action_fn)(struct sockaddr_dl *sdl,
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struct sockaddr_in *s_in, struct rt_msghdr *rtm);
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static int search(u_long addr, action_fn *action);
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static action_fn print_entry;
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static action_fn nuke_entry;
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static int delete(char *host);
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static void usage(void);
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static int set(int argc, char **argv);
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static int get(char *host);
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static int file(char *name);
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static struct rt_msghdr *rtmsg(int cmd,
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struct sockaddr_in *dst, struct sockaddr_dl *sdl);
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static int get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr);
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static struct sockaddr_in *getaddr(char *host);
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static int valid_type(int type);
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static int nflag; /* no reverse dns lookups */
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static char *rifname;
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static time_t expire_time;
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static int flags, doing_proxy;
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struct if_nameindex *ifnameindex;
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/* which function we're supposed to do */
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#define F_GET 1
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#define F_SET 2
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#define F_FILESET 3
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#define F_REPLACE 4
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#define F_DELETE 5
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#define SETFUNC(f) { if (func) usage(); func = (f); }
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int
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main(int argc, char *argv[])
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{
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int ch, func = 0;
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int rtn = 0;
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int aflag = 0; /* do it for all entries */
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while ((ch = getopt(argc, argv, "andfsSi:")) != -1)
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switch(ch) {
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case 'a':
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aflag = 1;
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break;
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case 'd':
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SETFUNC(F_DELETE);
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break;
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case 'n':
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nflag = 1;
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break;
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case 'S':
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SETFUNC(F_REPLACE);
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break;
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case 's':
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SETFUNC(F_SET);
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break;
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case 'f' :
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SETFUNC(F_FILESET);
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break;
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case 'i':
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rifname = optarg;
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break;
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case '?':
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default:
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usage();
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}
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argc -= optind;
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argv += optind;
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if (!func)
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func = F_GET;
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if (rifname) {
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if (func != F_GET && !(func == F_DELETE && aflag))
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errx(1, "-i not applicable to this operation");
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if (if_nametoindex(rifname) == 0) {
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if (errno == ENXIO)
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errx(1, "interface %s does not exist", rifname);
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else
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err(1, "if_nametoindex(%s)", rifname);
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}
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}
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switch (func) {
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case F_GET:
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if (aflag) {
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if (argc != 0)
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usage();
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search(0, print_entry);
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} else {
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if (argc != 1)
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usage();
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rtn = get(argv[0]);
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}
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break;
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case F_SET:
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case F_REPLACE:
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if (argc < 2 || argc > 6)
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usage();
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if (func == F_REPLACE)
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(void)delete(argv[0]);
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rtn = set(argc, argv) ? 1 : 0;
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break;
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case F_DELETE:
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if (aflag) {
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if (argc != 0)
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usage();
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search(0, nuke_entry);
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} else {
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if (argc != 1)
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usage();
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rtn = delete(argv[0]);
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}
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break;
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case F_FILESET:
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if (argc != 1)
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usage();
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rtn = file(argv[0]);
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break;
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}
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if (ifnameindex != NULL)
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if_freenameindex(ifnameindex);
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return (rtn);
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}
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/*
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* Process a file to set standard arp entries
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*/
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static int
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file(char *name)
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{
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FILE *fp;
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int i, retval;
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char line[100], arg[5][50], *args[5], *p;
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if ((fp = fopen(name, "r")) == NULL)
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err(1, "cannot open %s", name);
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args[0] = &arg[0][0];
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args[1] = &arg[1][0];
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args[2] = &arg[2][0];
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args[3] = &arg[3][0];
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args[4] = &arg[4][0];
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retval = 0;
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while(fgets(line, sizeof(line), fp) != NULL) {
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if ((p = strchr(line, '#')) != NULL)
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*p = '\0';
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for (p = line; isblank(*p); p++);
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if (*p == '\n' || *p == '\0')
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continue;
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i = sscanf(p, "%49s %49s %49s %49s %49s", arg[0], arg[1],
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arg[2], arg[3], arg[4]);
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if (i < 2) {
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warnx("bad line: %s", line);
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retval = 1;
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continue;
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}
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if (set(i, args))
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retval = 1;
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}
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fclose(fp);
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return (retval);
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}
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/*
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* Given a hostname, fills up a (static) struct sockaddr_in with
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* the address of the host and returns a pointer to the
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* structure.
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*/
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static struct sockaddr_in *
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getaddr(char *host)
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{
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struct hostent *hp;
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static struct sockaddr_in reply;
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bzero(&reply, sizeof(reply));
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reply.sin_len = sizeof(reply);
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reply.sin_family = AF_INET;
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reply.sin_addr.s_addr = inet_addr(host);
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if (reply.sin_addr.s_addr == INADDR_NONE) {
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if (!(hp = gethostbyname(host))) {
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warnx("%s: %s", host, hstrerror(h_errno));
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return (NULL);
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}
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bcopy((char *)hp->h_addr, (char *)&reply.sin_addr,
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sizeof reply.sin_addr);
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}
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return (&reply);
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}
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/*
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* Returns true if the type is a valid one for ARP.
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*/
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static int
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valid_type(int type)
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{
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switch (type) {
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case IFT_ETHER:
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case IFT_FDDI:
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case IFT_ISO88023:
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case IFT_ISO88024:
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case IFT_ISO88025:
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case IFT_L2VLAN:
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case IFT_BRIDGE:
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return (1);
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default:
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return (0);
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}
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}
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/*
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* Set an individual arp entry
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*/
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static int
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set(int argc, char **argv)
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{
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struct sockaddr_in *addr;
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struct sockaddr_in *dst; /* what are we looking for */
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struct sockaddr_dl *sdl;
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struct rt_msghdr *rtm;
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struct ether_addr *ea;
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char *host = argv[0], *eaddr = argv[1];
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struct sockaddr_dl sdl_m;
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argc -= 2;
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argv += 2;
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bzero(&sdl_m, sizeof(sdl_m));
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sdl_m.sdl_len = sizeof(sdl_m);
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sdl_m.sdl_family = AF_LINK;
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dst = getaddr(host);
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if (dst == NULL)
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return (1);
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doing_proxy = flags = expire_time = 0;
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while (argc-- > 0) {
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if (strncmp(argv[0], "temp", 4) == 0) {
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struct timespec tp;
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int max_age;
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size_t len = sizeof(max_age);
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clock_gettime(CLOCK_MONOTONIC, &tp);
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if (sysctlbyname("net.link.ether.inet.max_age",
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&max_age, &len, NULL, 0) != 0)
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err(1, "sysctlbyname");
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expire_time = tp.tv_sec + max_age;
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} else if (strncmp(argv[0], "pub", 3) == 0) {
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flags |= RTF_ANNOUNCE;
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doing_proxy = 1;
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if (argc && strncmp(argv[1], "only", 3) == 0) {
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/*
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* Compatibility: in pre FreeBSD 8 times
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* the "only" keyword used to mean that
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* an ARP entry should be announced, but
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* not installed into routing table.
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*/
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argc--; argv++;
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}
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} else if (strncmp(argv[0], "blackhole", 9) == 0) {
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if (flags & RTF_REJECT) {
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printf("Choose one of blackhole or reject, not both.\n");
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}
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flags |= RTF_BLACKHOLE;
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} else if (strncmp(argv[0], "reject", 6) == 0) {
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if (flags & RTF_BLACKHOLE) {
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printf("Choose one of blackhole or reject, not both.\n");
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}
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flags |= RTF_REJECT;
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} else if (strncmp(argv[0], "trail", 5) == 0) {
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/* XXX deprecated and undocumented feature */
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printf("%s: Sending trailers is no longer supported\n",
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host);
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}
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argv++;
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}
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ea = (struct ether_addr *)LLADDR(&sdl_m);
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if (doing_proxy && !strcmp(eaddr, "auto")) {
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if (!get_ether_addr(dst->sin_addr.s_addr, ea)) {
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printf("no interface found for %s\n",
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inet_ntoa(dst->sin_addr));
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return (1);
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}
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sdl_m.sdl_alen = ETHER_ADDR_LEN;
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} else {
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struct ether_addr *ea1 = ether_aton(eaddr);
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if (ea1 == NULL) {
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warnx("invalid Ethernet address '%s'", eaddr);
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return (1);
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} else {
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*ea = *ea1;
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sdl_m.sdl_alen = ETHER_ADDR_LEN;
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}
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}
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/*
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* In the case a proxy-arp entry is being added for
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* a remote end point, the RTF_ANNOUNCE flag in the
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* RTM_GET command is an indication to the kernel
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* routing code that the interface associated with
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* the prefix route covering the local end of the
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* PPP link should be returned, on which ARP applies.
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*/
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rtm = rtmsg(RTM_GET, dst, &sdl_m);
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if (rtm == NULL) {
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warn("%s", host);
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return (1);
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}
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addr = (struct sockaddr_in *)(rtm + 1);
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sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr);
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if ((sdl->sdl_family != AF_LINK) ||
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(rtm->rtm_flags & RTF_GATEWAY) ||
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!valid_type(sdl->sdl_type)) {
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printf("cannot intuit interface index and type for %s\n", host);
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return (1);
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}
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sdl_m.sdl_type = sdl->sdl_type;
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sdl_m.sdl_index = sdl->sdl_index;
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return (rtmsg(RTM_ADD, dst, &sdl_m) == NULL);
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}
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/*
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* Display an individual arp entry
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*/
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static int
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get(char *host)
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{
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struct sockaddr_in *addr;
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addr = getaddr(host);
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if (addr == NULL)
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return (1);
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if (0 == search(addr->sin_addr.s_addr, print_entry)) {
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printf("%s (%s) -- no entry",
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host, inet_ntoa(addr->sin_addr));
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if (rifname)
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printf(" on %s", rifname);
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printf("\n");
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return (1);
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}
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return (0);
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}
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/*
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* Delete an arp entry
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*/
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static int
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delete(char *host)
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{
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struct sockaddr_in *addr, *dst;
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struct rt_msghdr *rtm;
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struct sockaddr_dl *sdl;
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struct sockaddr_dl sdl_m;
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dst = getaddr(host);
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if (dst == NULL)
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return (1);
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/*
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* Perform a regular entry delete first.
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*/
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flags &= ~RTF_ANNOUNCE;
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/*
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* setup the data structure to notify the kernel
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* it is the ARP entry the RTM_GET is interested
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* in
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*/
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bzero(&sdl_m, sizeof(sdl_m));
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sdl_m.sdl_len = sizeof(sdl_m);
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sdl_m.sdl_family = AF_LINK;
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for (;;) { /* try twice */
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rtm = rtmsg(RTM_GET, dst, &sdl_m);
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if (rtm == NULL) {
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warn("%s", host);
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return (1);
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}
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addr = (struct sockaddr_in *)(rtm + 1);
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sdl = (struct sockaddr_dl *)(SA_SIZE(addr) + (char *)addr);
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/*
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* With the new L2/L3 restructure, the route
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* returned is a prefix route. The important
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* piece of information from the previous
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* RTM_GET is the interface index. In the
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* case of ECMP, the kernel will traverse
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* the route group for the given entry.
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*/
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if (sdl->sdl_family == AF_LINK &&
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!(rtm->rtm_flags & RTF_GATEWAY) &&
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valid_type(sdl->sdl_type) ) {
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addr->sin_addr.s_addr = dst->sin_addr.s_addr;
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break;
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}
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/*
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* Regualar entry delete failed, now check if there
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* is a proxy-arp entry to remove.
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*/
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if (flags & RTF_ANNOUNCE) {
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fprintf(stderr, "delete: cannot locate %s\n",host);
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return (1);
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}
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flags |= RTF_ANNOUNCE;
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}
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rtm->rtm_flags |= RTF_LLDATA;
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if (rtmsg(RTM_DELETE, dst, NULL) != NULL) {
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printf("%s (%s) deleted\n", host, inet_ntoa(addr->sin_addr));
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return (0);
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}
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return (1);
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}
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/*
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* Search the arp table and do some action on matching entries
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*/
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static int
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search(u_long addr, action_fn *action)
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{
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int mib[6];
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size_t needed;
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char *lim, *buf, *next;
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struct rt_msghdr *rtm;
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struct sockaddr_in *sin2;
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struct sockaddr_dl *sdl;
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char ifname[IF_NAMESIZE];
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int st, found_entry = 0;
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mib[0] = CTL_NET;
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mib[1] = PF_ROUTE;
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mib[2] = 0;
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mib[3] = AF_INET;
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mib[4] = NET_RT_FLAGS;
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#ifdef RTF_LLINFO
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mib[5] = RTF_LLINFO;
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#else
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mib[5] = 0;
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#endif
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if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
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err(1, "route-sysctl-estimate");
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if (needed == 0) /* empty table */
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return 0;
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buf = NULL;
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for (;;) {
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buf = reallocf(buf, needed);
|
|
if (buf == NULL)
|
|
errx(1, "could not reallocate memory");
|
|
st = sysctl(mib, 6, buf, &needed, NULL, 0);
|
|
if (st == 0 || errno != ENOMEM)
|
|
break;
|
|
needed += needed / 8;
|
|
}
|
|
if (st == -1)
|
|
err(1, "actual retrieval of routing table");
|
|
lim = buf + needed;
|
|
for (next = buf; next < lim; next += rtm->rtm_msglen) {
|
|
rtm = (struct rt_msghdr *)next;
|
|
sin2 = (struct sockaddr_in *)(rtm + 1);
|
|
sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2));
|
|
if (rifname && if_indextoname(sdl->sdl_index, ifname) &&
|
|
strcmp(ifname, rifname))
|
|
continue;
|
|
if (addr) {
|
|
if (addr != sin2->sin_addr.s_addr)
|
|
continue;
|
|
found_entry = 1;
|
|
}
|
|
(*action)(sdl, sin2, rtm);
|
|
}
|
|
free(buf);
|
|
return (found_entry);
|
|
}
|
|
|
|
/*
|
|
* Display an arp entry
|
|
*/
|
|
|
|
static void
|
|
print_entry(struct sockaddr_dl *sdl,
|
|
struct sockaddr_in *addr, struct rt_msghdr *rtm)
|
|
{
|
|
const char *host;
|
|
struct hostent *hp;
|
|
struct iso88025_sockaddr_dl_data *trld;
|
|
struct if_nameindex *p;
|
|
int seg;
|
|
|
|
if (ifnameindex == NULL)
|
|
if ((ifnameindex = if_nameindex()) == NULL)
|
|
err(1, "cannot retrieve interface names");
|
|
|
|
if (nflag == 0)
|
|
hp = gethostbyaddr((caddr_t)&(addr->sin_addr),
|
|
sizeof addr->sin_addr, AF_INET);
|
|
else
|
|
hp = 0;
|
|
if (hp)
|
|
host = hp->h_name;
|
|
else {
|
|
host = "?";
|
|
if (h_errno == TRY_AGAIN)
|
|
nflag = 1;
|
|
}
|
|
printf("%s (%s) at ", host, inet_ntoa(addr->sin_addr));
|
|
if (sdl->sdl_alen) {
|
|
if ((sdl->sdl_type == IFT_ETHER ||
|
|
sdl->sdl_type == IFT_L2VLAN ||
|
|
sdl->sdl_type == IFT_BRIDGE) &&
|
|
sdl->sdl_alen == ETHER_ADDR_LEN)
|
|
printf("%s", ether_ntoa((struct ether_addr *)LLADDR(sdl)));
|
|
else {
|
|
int n = sdl->sdl_nlen > 0 ? sdl->sdl_nlen + 1 : 0;
|
|
|
|
printf("%s", link_ntoa(sdl) + n);
|
|
}
|
|
} else
|
|
printf("(incomplete)");
|
|
|
|
for (p = ifnameindex; p && ifnameindex->if_index &&
|
|
ifnameindex->if_name; p++) {
|
|
if (p->if_index == sdl->sdl_index) {
|
|
printf(" on %s", p->if_name);
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (rtm->rtm_rmx.rmx_expire == 0)
|
|
printf(" permanent");
|
|
else {
|
|
static struct timespec tp;
|
|
if (tp.tv_sec == 0)
|
|
clock_gettime(CLOCK_MONOTONIC, &tp);
|
|
if ((expire_time = rtm->rtm_rmx.rmx_expire - tp.tv_sec) > 0)
|
|
printf(" expires in %d seconds", (int)expire_time);
|
|
else
|
|
printf(" expired");
|
|
}
|
|
if (rtm->rtm_flags & RTF_ANNOUNCE)
|
|
printf(" published");
|
|
switch(sdl->sdl_type) {
|
|
case IFT_ETHER:
|
|
printf(" [ethernet]");
|
|
break;
|
|
case IFT_ISO88025:
|
|
printf(" [token-ring]");
|
|
trld = SDL_ISO88025(sdl);
|
|
if (trld->trld_rcf != 0) {
|
|
printf(" rt=%x", ntohs(trld->trld_rcf));
|
|
for (seg = 0;
|
|
seg < ((TR_RCF_RIFLEN(trld->trld_rcf) - 2 ) / 2);
|
|
seg++)
|
|
printf(":%x", ntohs(*(trld->trld_route[seg])));
|
|
}
|
|
break;
|
|
case IFT_FDDI:
|
|
printf(" [fddi]");
|
|
break;
|
|
case IFT_ATM:
|
|
printf(" [atm]");
|
|
break;
|
|
case IFT_L2VLAN:
|
|
printf(" [vlan]");
|
|
break;
|
|
case IFT_IEEE1394:
|
|
printf(" [firewire]");
|
|
break;
|
|
case IFT_BRIDGE:
|
|
printf(" [bridge]");
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
printf("\n");
|
|
|
|
}
|
|
|
|
/*
|
|
* Nuke an arp entry
|
|
*/
|
|
static void
|
|
nuke_entry(struct sockaddr_dl *sdl __unused,
|
|
struct sockaddr_in *addr, struct rt_msghdr *rtm __unused)
|
|
{
|
|
char ip[20];
|
|
|
|
snprintf(ip, sizeof(ip), "%s", inet_ntoa(addr->sin_addr));
|
|
delete(ip);
|
|
}
|
|
|
|
static void
|
|
usage(void)
|
|
{
|
|
fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
|
|
"usage: arp [-n] [-i interface] hostname",
|
|
" arp [-n] [-i interface] -a",
|
|
" arp -d hostname [pub]",
|
|
" arp -d [-i interface] -a",
|
|
" arp -s hostname ether_addr [temp] [reject | blackhole] [pub [only]]",
|
|
" arp -S hostname ether_addr [temp] [reject | blackhole] [pub [only]]",
|
|
" arp -f filename");
|
|
exit(1);
|
|
}
|
|
|
|
static struct rt_msghdr *
|
|
rtmsg(int cmd, struct sockaddr_in *dst, struct sockaddr_dl *sdl)
|
|
{
|
|
static int seq;
|
|
int rlen;
|
|
int l;
|
|
struct sockaddr_in so_mask, *som = &so_mask;
|
|
static int s = -1;
|
|
static pid_t pid;
|
|
|
|
static struct {
|
|
struct rt_msghdr m_rtm;
|
|
char m_space[512];
|
|
} m_rtmsg;
|
|
|
|
struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
|
|
char *cp = m_rtmsg.m_space;
|
|
|
|
if (s < 0) { /* first time: open socket, get pid */
|
|
s = socket(PF_ROUTE, SOCK_RAW, 0);
|
|
if (s < 0)
|
|
err(1, "socket");
|
|
pid = getpid();
|
|
}
|
|
bzero(&so_mask, sizeof(so_mask));
|
|
so_mask.sin_len = 8;
|
|
so_mask.sin_addr.s_addr = 0xffffffff;
|
|
|
|
errno = 0;
|
|
/*
|
|
* XXX RTM_DELETE relies on a previous RTM_GET to fill the buffer
|
|
* appropriately.
|
|
*/
|
|
if (cmd == RTM_DELETE)
|
|
goto doit;
|
|
bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
|
|
rtm->rtm_flags = flags;
|
|
rtm->rtm_version = RTM_VERSION;
|
|
|
|
switch (cmd) {
|
|
default:
|
|
errx(1, "internal wrong cmd");
|
|
case RTM_ADD:
|
|
rtm->rtm_addrs |= RTA_GATEWAY;
|
|
rtm->rtm_rmx.rmx_expire = expire_time;
|
|
rtm->rtm_inits = RTV_EXPIRE;
|
|
rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA);
|
|
if (doing_proxy) {
|
|
rtm->rtm_addrs |= RTA_NETMASK;
|
|
rtm->rtm_flags &= ~RTF_HOST;
|
|
}
|
|
/* FALLTHROUGH */
|
|
case RTM_GET:
|
|
rtm->rtm_addrs |= RTA_DST;
|
|
}
|
|
#define NEXTADDR(w, s) \
|
|
do { \
|
|
if ((s) != NULL && rtm->rtm_addrs & (w)) { \
|
|
bcopy((s), cp, sizeof(*(s))); \
|
|
cp += SA_SIZE(s); \
|
|
} \
|
|
} while (0)
|
|
|
|
NEXTADDR(RTA_DST, dst);
|
|
NEXTADDR(RTA_GATEWAY, sdl);
|
|
NEXTADDR(RTA_NETMASK, som);
|
|
|
|
rtm->rtm_msglen = cp - (char *)&m_rtmsg;
|
|
doit:
|
|
l = rtm->rtm_msglen;
|
|
rtm->rtm_seq = ++seq;
|
|
rtm->rtm_type = cmd;
|
|
if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
|
|
if (errno != ESRCH || cmd != RTM_DELETE) {
|
|
warn("writing to routing socket");
|
|
return (NULL);
|
|
}
|
|
}
|
|
do {
|
|
l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
|
|
} while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
|
|
if (l < 0)
|
|
warn("read from routing socket");
|
|
return (rtm);
|
|
}
|
|
|
|
/*
|
|
* get_ether_addr - get the hardware address of an interface on the
|
|
* the same subnet as ipaddr.
|
|
*/
|
|
#define MAX_IFS 32
|
|
|
|
static int
|
|
get_ether_addr(in_addr_t ipaddr, struct ether_addr *hwaddr)
|
|
{
|
|
struct ifreq *ifr, *ifend, *ifp;
|
|
in_addr_t ina, mask;
|
|
struct sockaddr_dl *dla;
|
|
struct ifreq ifreq;
|
|
struct ifconf ifc;
|
|
struct ifreq ifs[MAX_IFS];
|
|
int sock;
|
|
int retval = 0;
|
|
|
|
sock = socket(AF_INET, SOCK_DGRAM, 0);
|
|
if (sock < 0)
|
|
err(1, "socket");
|
|
|
|
ifc.ifc_len = sizeof(ifs);
|
|
ifc.ifc_req = ifs;
|
|
if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
|
|
warnx("ioctl(SIOCGIFCONF)");
|
|
goto done;
|
|
}
|
|
|
|
#define NEXTIFR(i) \
|
|
((struct ifreq *)((char *)&(i)->ifr_addr \
|
|
+ MAX((i)->ifr_addr.sa_len, sizeof((i)->ifr_addr))) )
|
|
|
|
/*
|
|
* Scan through looking for an interface with an Internet
|
|
* address on the same subnet as `ipaddr'.
|
|
*/
|
|
ifend = (struct ifreq *)(ifc.ifc_buf + ifc.ifc_len);
|
|
for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr) ) {
|
|
if (ifr->ifr_addr.sa_family != AF_INET)
|
|
continue;
|
|
strncpy(ifreq.ifr_name, ifr->ifr_name,
|
|
sizeof(ifreq.ifr_name));
|
|
ifreq.ifr_addr = ifr->ifr_addr;
|
|
/*
|
|
* Check that the interface is up,
|
|
* and not point-to-point or loopback.
|
|
*/
|
|
if (ioctl(sock, SIOCGIFFLAGS, &ifreq) < 0)
|
|
continue;
|
|
if ((ifreq.ifr_flags &
|
|
(IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|
|
|
IFF_LOOPBACK|IFF_NOARP))
|
|
!= (IFF_UP|IFF_BROADCAST))
|
|
continue;
|
|
/*
|
|
* Get its netmask and check that it's on
|
|
* the right subnet.
|
|
*/
|
|
if (ioctl(sock, SIOCGIFNETMASK, &ifreq) < 0)
|
|
continue;
|
|
mask = ((struct sockaddr_in *)
|
|
&ifreq.ifr_addr)->sin_addr.s_addr;
|
|
ina = ((struct sockaddr_in *)
|
|
&ifr->ifr_addr)->sin_addr.s_addr;
|
|
if ((ipaddr & mask) == (ina & mask))
|
|
break; /* ok, we got it! */
|
|
}
|
|
|
|
if (ifr >= ifend)
|
|
goto done;
|
|
|
|
/*
|
|
* Now scan through again looking for a link-level address
|
|
* for this interface.
|
|
*/
|
|
ifp = ifr;
|
|
for (ifr = ifc.ifc_req; ifr < ifend; ifr = NEXTIFR(ifr))
|
|
if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 &&
|
|
ifr->ifr_addr.sa_family == AF_LINK)
|
|
break;
|
|
if (ifr >= ifend)
|
|
goto done;
|
|
/*
|
|
* Found the link-level address - copy it out
|
|
*/
|
|
dla = (struct sockaddr_dl *) &ifr->ifr_addr;
|
|
memcpy(hwaddr, LLADDR(dla), dla->sdl_alen);
|
|
printf("using interface %s for proxy with address ",
|
|
ifp->ifr_name);
|
|
printf("%s\n", ether_ntoa(hwaddr));
|
|
retval = dla->sdl_alen;
|
|
done:
|
|
close(sock);
|
|
return (retval);
|
|
}
|