NetBSD/usr.sbin/arp/arp.c

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/* $NetBSD: arp.c,v 1.12 1995/04/24 13:25:18 cgd Exp $ */
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/*
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* Copyright (c) 1984, 1993
* The Regents of the University of California. All rights reserved.
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*
* This code is derived from software contributed to Berkeley by
* Sun Microsystems, Inc.
*
* 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 University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* 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
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static char copyright[] =
"@(#) Copyright (c) 1984, 1993\n\
The Regents of the University of California. All rights reserved.\n";
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#endif /* not lint */
#ifndef lint
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/*static char sccsid[] = "from: @(#)arp.c 8.2 (Berkeley) 1/2/94";*/
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static char *rcsid = "$NetBSD: arp.c,v 1.12 1995/04/24 13:25:18 cgd Exp $";
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#endif /* not lint */
/*
* arp - display, set, and delete arp table entries
*/
#include <sys/param.h>
#include <sys/file.h>
#include <sys/socket.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#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 <netdb.h>
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#include <errno.h>
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#include <err.h>
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#include <nlist.h>
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <paths.h>
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int delete __P((const char *, const char *));
void dump __P((u_long));
int ether_aton __P((const char *, u_char *));
void ether_print __P((const u_char *));
int file __P((char *));
void get __P((const char *));
int getinetaddr __P((const char *, struct in_addr *));
void getsocket __P((void));
int rtmsg __P((int));
int set __P((int, char **));
void usage __P((void));
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static int pid;
static int nflag;
static int s = -1;
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int
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main(argc, argv)
int argc;
char **argv;
{
int ch;
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pid = getpid();
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while ((ch = getopt(argc, argv, "andsf")) != EOF)
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switch((char)ch) {
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case 'a':
dump(0);
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return (0);
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case 'd':
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if (argc < 3 || argc > 4)
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usage();
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(void)delete(argv[2], argv[3]);
return (0);
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case 'n':
nflag = 1;
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break;
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case 's':
if (argc < 4 || argc > 7)
usage();
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return (set(argc-2, &argv[2]) ? 1 : 0);
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case 'f':
if (argc != 3)
usage();
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return (file(argv[2]));
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case '?':
default:
usage();
}
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if (argc == 2 || (argc == 3 && nflag))
get(argv[argc - 1]);
else
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usage();
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return (0);
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}
/*
* Process a file to set standard arp entries
*/
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int
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file(name)
char *name;
{
char line[100], arg[5][50], *args[5];
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int i, retval;
FILE *fp;
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if ((fp = fopen(name, "r")) == NULL)
err(1, "cannot open %s", name);
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args[0] = &arg[0][0];
args[1] = &arg[1][0];
args[2] = &arg[2][0];
args[3] = &arg[3][0];
args[4] = &arg[4][0];
retval = 0;
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while (fgets(line, 100, fp) != NULL) {
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i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2],
arg[3], arg[4]);
if (i < 2) {
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warnx("bad line: %s", line);
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retval = 1;
continue;
}
if (set(i, args))
retval = 1;
}
fclose(fp);
return (retval);
}
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void
getsocket()
{
if (s >= 0)
return;
s = socket(PF_ROUTE, SOCK_RAW, 0);
if (s < 0)
err(1, "socket");
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}
struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
int expire_time, flags, export_only, doing_proxy, found_entry;
struct {
struct rt_msghdr m_rtm;
char m_space[512];
} m_rtmsg;
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/*
* Set an individual arp entry
*/
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int
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set(argc, argv)
int argc;
char **argv;
{
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register struct sockaddr_inarp *sin;
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register struct sockaddr_dl *sdl;
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register struct rt_msghdr *rtm;
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u_char *ea;
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char *host = argv[0], *eaddr;
sin = &sin_m;
rtm = &(m_rtmsg.m_rtm);
eaddr = argv[1];
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getsocket();
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argc -= 2;
argv += 2;
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sdl_m = blank_sdl; /* struct copy */
sin_m = blank_sin; /* struct copy */
if (getinetaddr(host, &sin->sin_addr) == -1)
return (1);
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ea = (u_char *)LLADDR(&sdl_m);
if (ether_aton(eaddr, ea) == 0)
sdl_m.sdl_alen = 6;
doing_proxy = flags = export_only = expire_time = 0;
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while (argc-- > 0) {
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if (strncmp(argv[0], "temp", 4) == 0) {
struct timeval time;
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(void)gettimeofday(&time, 0);
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expire_time = time.tv_sec + 20 * 60;
}
else if (strncmp(argv[0], "pub", 3) == 0) {
flags |= RTF_ANNOUNCE;
doing_proxy = SIN_PROXY;
} else if (strncmp(argv[0], "trail", 5) == 0) {
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(void)printf(
"%s: Sending trailers is no longer supported\n",
host);
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}
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argv++;
}
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tryagain:
if (rtmsg(RTM_GET) < 0) {
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warn("%s", host);
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return (1);
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}
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sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
if (sdl->sdl_family == AF_LINK &&
(rtm->rtm_flags & RTF_LLINFO) &&
!(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
case IFT_ISO88024: case IFT_ISO88025:
goto overwrite;
}
if (doing_proxy == 0) {
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(void)printf("set: can only proxy for %s\n", host);
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return (1);
}
if (sin_m.sin_other & SIN_PROXY) {
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(void)printf(
"set: proxy entry exists for non 802 device\n");
return (1);
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}
sin_m.sin_other = SIN_PROXY;
export_only = 1;
goto tryagain;
}
overwrite:
if (sdl->sdl_family != AF_LINK) {
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(void)printf("cannot intuit interface index and type for %s\n",
host);
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return (1);
}
sdl_m.sdl_type = sdl->sdl_type;
sdl_m.sdl_index = sdl->sdl_index;
return (rtmsg(RTM_ADD));
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}
/*
* Display an individual arp entry
*/
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void
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get(host)
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const char *host;
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{
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struct sockaddr_inarp *sin;
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u_char *ea;
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sin = &sin_m;
sin_m = blank_sin; /* struct copy */
if (getinetaddr(host, &sin->sin_addr) == -1)
exit(1);
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dump(sin->sin_addr.s_addr);
if (found_entry == 0) {
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(void)printf("%s (%s) -- no entry\n", host,
inet_ntoa(sin->sin_addr));
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exit(1);
}
}
/*
* Delete an arp entry
*/
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int
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delete(host, info)
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const char *host;
const char *info;
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{
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register struct sockaddr_inarp *sin;
register struct rt_msghdr *rtm;
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struct sockaddr_dl *sdl;
u_char *ea;
char *eaddr;
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sin = &sin_m;
rtm = &m_rtmsg.m_rtm;
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if (info && strncmp(info, "pro", 3) )
export_only = 1;
getsocket();
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sin_m = blank_sin; /* struct copy */
if (getinetaddr(host, &sin->sin_addr) == -1)
return (1);
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tryagain:
if (rtmsg(RTM_GET) < 0) {
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warn("%s", host);
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return (1);
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}
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sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
if (sdl->sdl_family == AF_LINK &&
(rtm->rtm_flags & RTF_LLINFO) &&
!(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
case IFT_ISO88024: case IFT_ISO88025:
goto delete;
}
}
if (sin_m.sin_other & SIN_PROXY) {
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warnx("delete: can't locate %s", host);
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return (1);
} else {
sin_m.sin_other = SIN_PROXY;
goto tryagain;
}
delete:
if (sdl->sdl_family != AF_LINK) {
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(void)printf("cannot locate %s\n", host);
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return (1);
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}
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if (rtmsg(RTM_DELETE))
return (1);
(void)printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr));
return (0);
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}
/*
* Dump the entire arp table
*/
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void
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dump(addr)
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u_long addr;
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{
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int mib[6];
size_t needed;
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char *host, *lim, *buf, *next;
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struct rt_msghdr *rtm;
struct sockaddr_inarp *sin;
struct sockaddr_dl *sdl;
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extern int h_errno;
struct hostent *hp;
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mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = AF_INET;
mib[4] = NET_RT_FLAGS;
mib[5] = RTF_LLINFO;
if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
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err(1, "route-sysctl-estimate");
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if ((buf = malloc(needed)) == NULL)
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err(1, "malloc");
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if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
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err(1, "actual retrieval of routing table");
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lim = buf + needed;
for (next = buf; next < lim; next += rtm->rtm_msglen) {
rtm = (struct rt_msghdr *)next;
sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(sin + 1);
if (addr) {
if (addr != sin->sin_addr.s_addr)
continue;
found_entry = 1;
}
if (nflag == 0)
hp = gethostbyaddr((caddr_t)&(sin->sin_addr),
sizeof sin->sin_addr, AF_INET);
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else
hp = 0;
if (hp)
host = hp->h_name;
else {
host = "?";
if (h_errno == TRY_AGAIN)
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nflag = 1;
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}
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(void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr));
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if (sdl->sdl_alen)
ether_print(LLADDR(sdl));
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else
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(void)printf("(incomplete)");
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if (rtm->rtm_rmx.rmx_expire == 0)
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(void)printf(" permanent");
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if (sin->sin_other & SIN_PROXY)
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(void)printf(" published (proxy only)");
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if (rtm->rtm_addrs & RTA_NETMASK) {
sin = (struct sockaddr_inarp *)
(sdl->sdl_len + (char *)sdl);
if (sin->sin_addr.s_addr == 0xffffffff)
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(void)printf(" published");
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if (sin->sin_len != 8)
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(void)printf("(wierd)");
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}
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(void)printf("\n");
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}
}
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void
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ether_print(cp)
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const u_char *cp;
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{
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(void)printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4],
cp[5]);
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}
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int
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ether_aton(a, n)
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const char *a;
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u_char *n;
{
int i, o[6];
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i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], &o[3], &o[4],
&o[5]);
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if (i != 6) {
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warnx("invalid Ethernet address '%s'", a);
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return (1);
}
for (i=0; i<6; i++)
n[i] = o[i];
return (0);
}
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void
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usage()
{
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(void)fprintf(stderr, "usage: arp [-n] hostname\n");
(void)fprintf(stderr, "usage: arp [-n] -a\n");
(void)fprintf(stderr, "usage: arp -d hostname\n");
(void)fprintf(stderr,
"usage: arp -s hostname ether_addr [temp] [pub]\n");
(void)fprintf(stderr, "usage: arp -f filename\n");
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exit(1);
}
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int
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rtmsg(cmd)
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int cmd;
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{
static int seq;
int rlen;
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register struct rt_msghdr *rtm;
register char *cp;
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register int l;
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rtm = &m_rtmsg.m_rtm;
cp = m_rtmsg.m_space;
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errno = 0;
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if (cmd == RTM_DELETE)
goto doit;
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(void)memset(&m_rtmsg, 0, sizeof(m_rtmsg));
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rtm->rtm_flags = flags;
rtm->rtm_version = RTM_VERSION;
switch (cmd) {
default:
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errx(1, "internal wrong cmd");
/*NOTREACHED*/
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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);
sin_m.sin_other = 0;
if (doing_proxy) {
if (export_only)
sin_m.sin_other = SIN_PROXY;
else {
rtm->rtm_addrs |= RTA_NETMASK;
rtm->rtm_flags &= ~RTF_HOST;
}
}
/* FALLTHROUGH */
case RTM_GET:
rtm->rtm_addrs |= RTA_DST;
}
#define NEXTADDR(w, s) \
if (rtm->rtm_addrs & (w)) { \
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(void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);}
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NEXTADDR(RTA_DST, sin_m);
NEXTADDR(RTA_GATEWAY, sdl_m);
NEXTADDR(RTA_NETMASK, so_mask);
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) {
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warn("writing to routing socket");
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return (-1);
}
}
do {
l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
} while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
if (l < 0)
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warn("read from routing socket");
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return (0);
}
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int
getinetaddr(host, inap)
const char *host;
struct in_addr *inap;
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{
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extern char *__progname; /* Program name, from crt0. */
struct hostent *hp;
u_long addr;
if (inet_aton(host, inap) == 1)
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return (0);
if ((hp = gethostbyname(host)) == NULL) {
(void)fprintf(stderr, "%s: %s: ", __progname, host);
herror(NULL);
return (-1);
}
(void)memcpy(inap, hp->h_addr, sizeof(*inap));
return (0);
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}