[unix-history] / usr.sbin / arp / arp.c

/*
 * Copyright (c) 1984 Regents of the University of California.
 * All rights reserved.
 *
 * 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
char copyright[] =
"@(#) Copyright (c) 1984 Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)arp.c	5.11.1.1 (Berkeley) 7/22/91";
#endif /* not lint */

/*
 * arp - display, set, and delete arp table entries
 */

#include <sys/param.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/ioctl.h>

#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/if_ether.h>

#include <errno.h>
#include <nlist.h>
#include <kvm.h>
#include <stdio.h>
#include <paths.h>

extern int errno;

main(argc, argv)
	int argc;
	char **argv;
{
	int ch;

	while ((ch = getopt(argc, argv, "adsf")) != EOF)
		switch((char)ch) {
		case 'a': {
			char *mem = 0;

			if (argc > 4)
				usage();
			if (argc == 4) {
				mem = argv[3];
			}
			dump((argc >= 3) ? argv[2] : _PATH_UNIX, mem);
			exit(0);
		}
		case 'd':
			if (argc != 3)
				usage();
			delete(argv[2]);
			exit(0);
		case 's':
			if (argc < 4 || argc > 7)
				usage();
			exit(set(argc-2, &argv[2]) ? 1 : 0);
		case 'f':
			if (argc != 3)
				usage();
			exit (file(argv[2]) ? 1 : 0);
		case '?':
		default:
			usage();
		}
	if (argc != 2)
		usage();
	get(argv[1]);
	exit(0);
}

/*
 * Process a file to set standard arp entries
 */
file(name)
	char *name;
{
	FILE *fp;
	int i, retval;
	char line[100], arg[5][50], *args[5];

	if ((fp = fopen(name, "r")) == NULL) {
		fprintf(stderr, "arp: cannot open %s\n", name);
		exit(1);
	}
	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;
	while(fgets(line, 100, fp) != NULL) {
		i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2],
		    arg[3], arg[4]);
		if (i < 2) {
			fprintf(stderr, "arp: bad line: %s\n", line);
			retval = 1;
			continue;
		}
		if (set(i, args))
			retval = 1;
	}
	fclose(fp);
	return (retval);
}

/*
 * Set an individual arp entry 
 */
set(argc, argv)
	int argc;
	char **argv;
{
	struct arpreq ar;
	struct hostent *hp;
	struct sockaddr_in *sin;
	u_char *ea;
	int s;
	char *host = argv[0], *eaddr = argv[1];

	argc -= 2;
	argv += 2;
	bzero((caddr_t)&ar, sizeof ar);
	sin = (struct sockaddr_in *)&ar.arp_pa;
	sin->sin_family = AF_INET;
	sin->sin_addr.s_addr = inet_addr(host);
	if (sin->sin_addr.s_addr == -1) {
		if (!(hp = gethostbyname(host))) {
			fprintf(stderr, "arp: %s: ", host);
			herror((char *)NULL);
			return (1);
		}
		bcopy((char *)hp->h_addr, (char *)&sin->sin_addr,
		    sizeof sin->sin_addr);
	}
	ea = (u_char *)ar.arp_ha.sa_data;
	if (ether_aton(eaddr, ea))
		return (1);
	ar.arp_flags = ATF_PERM;
	while (argc-- > 0) {
		if (strncmp(argv[0], "temp", 4) == 0)
			ar.arp_flags &= ~ATF_PERM;
		else if (strncmp(argv[0], "pub", 3) == 0)
			ar.arp_flags |= ATF_PUBL;
		else if (strncmp(argv[0], "trail", 5) == 0)
			ar.arp_flags |= ATF_USETRAILERS;
		argv++;
	}
	
	s = socket(AF_INET, SOCK_DGRAM, 0);
	if (s < 0) {
		perror("arp: socket");
		exit(1);
	}
	if (ioctl(s, SIOCSARP, (caddr_t)&ar) < 0) {
		perror(host);
		exit(1);
	}
	close(s);
	return (0);
}

/*
 * Display an individual arp entry
 */
get(host)
	char *host;
{
	struct arpreq ar;
	struct hostent *hp;
	struct sockaddr_in *sin;
	u_char *ea;
	int s;

	bzero((caddr_t)&ar, sizeof ar);
	ar.arp_pa.sa_family = AF_INET;
	sin = (struct sockaddr_in *)&ar.arp_pa;
	sin->sin_family = AF_INET;
	sin->sin_addr.s_addr = inet_addr(host);
	if (sin->sin_addr.s_addr == -1) {
		if (!(hp = gethostbyname(host))) {
			fprintf(stderr, "arp: %s: ", host);
			herror((char *)NULL);
			exit(1);
		}
		bcopy((char *)hp->h_addr, (char *)&sin->sin_addr,
		    sizeof sin->sin_addr);
	}
	s = socket(AF_INET, SOCK_DGRAM, 0);
	if (s < 0) {
		perror("arp: socket");
		exit(1);
	}
	if (ioctl(s, SIOCGARP, (caddr_t)&ar) < 0) {
		if (errno == ENXIO)
			printf("%s (%s) -- no entry\n",
			    host, inet_ntoa(sin->sin_addr));
		else
			perror("SIOCGARP");
		exit(1);
	}
	close(s);
	ea = (u_char *)ar.arp_ha.sa_data;
	printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr));
	if (ar.arp_flags & ATF_COM)
		ether_print(ea);
	else
		printf("(incomplete)");
	if (ar.arp_flags & ATF_PERM)
		printf(" permanent");
	if (ar.arp_flags & ATF_PUBL)
		printf(" published");
	if (ar.arp_flags & ATF_USETRAILERS)
		printf(" trailers");
	printf("\n");
}

/*
 * Delete an arp entry 
 */
delete(host)
	char *host;
{
	struct arpreq ar;
	struct hostent *hp;
	struct sockaddr_in *sin;
	int s;

	bzero((caddr_t)&ar, sizeof ar);
	ar.arp_pa.sa_family = AF_INET;
	sin = (struct sockaddr_in *)&ar.arp_pa;
	sin->sin_family = AF_INET;
	sin->sin_addr.s_addr = inet_addr(host);
	if (sin->sin_addr.s_addr == -1) {
		if (!(hp = gethostbyname(host))) {
			fprintf(stderr, "arp: %s: ", host);
			herror((char *)NULL);
			exit(1);
		}
		bcopy((char *)hp->h_addr, (char *)&sin->sin_addr,
		    sizeof sin->sin_addr);
	}
	s = socket(AF_INET, SOCK_DGRAM, 0);
	if (s < 0) {
		perror("arp: socket");
		exit(1);
	}
	if (ioctl(s, SIOCDARP, (caddr_t)&ar) < 0) {
		if (errno == ENXIO)
			printf("%s (%s) -- no entry\n",
			    host, inet_ntoa(sin->sin_addr));
		else
			perror("SIOCDARP");
		exit(1);
	}
	close(s);
	printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr));
}

struct nlist nl[] = {
#define	X_ARPTAB	0
	{ "_arptab" },
#define	X_ARPTAB_SIZE	1
	{ "_arptab_size" },
	{ "" },
};

/*
 * Dump the entire arp table
 */
dump(kernel, mem)
	char *kernel, *mem;
{
	extern int h_errno;
	struct arptab *at;
	struct hostent *hp;
	int bynumber, mf, arptab_size, sz;
	char *host, *malloc();
	off_t lseek();

	if (kvm_openfiles(kernel, mem, NULL) == -1) {
		fprintf(stderr, "arp: kvm_openfiles: %s\n", kvm_geterr());
		exit(1);
	}
	if (kvm_nlist(nl) < 0 || nl[X_ARPTAB_SIZE].n_type == 0) {
		fprintf(stderr, "arp: %s: bad namelist\n", kernel);
		exit(1);
	}
	if (kvm_read((void *)(nl[X_ARPTAB_SIZE].n_value),
		     &arptab_size, sizeof arptab_size) == -1 ||
	    arptab_size <= 0 || arptab_size > 1000) {
		fprintf(stderr, "arp: %s: namelist wrong\n", kernel);
		exit(1);
	}
	sz = arptab_size * sizeof (struct arptab);
	at = (struct arptab *)malloc((u_int)sz);
	if (at == NULL) {
		fputs("arp: can't get memory for arptab.\n", stderr);
		exit(1);
	}
	if (kvm_read((void *)(nl[X_ARPTAB].n_value), (char *)at, sz) == -1) {
		perror("arp: error reading arptab");
		exit(1);
	}
	for (bynumber = 0; arptab_size-- > 0; at++) {
		if (at->at_iaddr.s_addr == 0 || at->at_flags == 0)
			continue;
		if (bynumber == 0)
			hp = gethostbyaddr((caddr_t)&at->at_iaddr,
			    sizeof at->at_iaddr, AF_INET);
		else
			hp = 0;
		if (hp)
			host = hp->h_name;
		else {
			host = "?";
			if (h_errno == TRY_AGAIN)
				bynumber = 1;
		}
		printf("%s (%s) at ", host, inet_ntoa(at->at_iaddr));
		if (at->at_flags & ATF_COM)
			ether_print(at->at_enaddr);
		else
			printf("(incomplete)");
		if (at->at_flags & ATF_PERM)
			printf(" permanent");
		if (at->at_flags & ATF_PUBL)
			printf(" published");
		if (at->at_flags & ATF_USETRAILERS)
			printf(" trailers");
		printf("\n");
	}
}

ether_print(cp)
	u_char *cp;
{
	printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]);
}

ether_aton(a, n)
	char *a;
	u_char *n;
{
	int i, o[6];

	i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2],
					   &o[3], &o[4], &o[5]);
	if (i != 6) {
		fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a);
		return (1);
	}
	for (i=0; i<6; i++)
		n[i] = o[i];
	return (0);
}

usage()
{
	printf("usage: arp hostname\n");
	printf("       arp -a [kernel] [kernel_memory]\n");
	printf("       arp -d hostname\n");
	printf("       arp -s hostname ether_addr [temp] [pub] [trail]\n");
	printf("       arp -f filename\n");
	exit(1);
}
Commit	Line	Data
15637ed4 RG	1	/*
	2	* Copyright (c) 1984 Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* Sun Microsystems, Inc.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. All advertising materials mentioning features or use of this software
	17	* must display the following acknowledgement:
	18	* This product includes software developed by the University of
	19	* California, Berkeley and its contributors.
	20	* 4. Neither the name of the University nor the names of its contributors
	21	* may be used to endorse or promote products derived from this software
	22	* without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
	35	*/
	36
	37	#ifndef lint
	38	char copyright[] =
	39	"@(#) Copyright (c) 1984 Regents of the University of California.\n\
	40	All rights reserved.\n";
	41	#endif /* not lint */
	42
	43	#ifndef lint
	44	static char sccsid[] = "@(#)arp.c 5.11.1.1 (Berkeley) 7/22/91";
	45	#endif /* not lint */
	46
	47	/*
	48	* arp - display, set, and delete arp table entries
	49	*/
	50
	51	#include <sys/param.h>
	52	#include <sys/file.h>
	53	#include <sys/socket.h>
	54	#include <sys/ioctl.h>
	55
	56	#include <netdb.h>
	57	#include <netinet/in.h>
422a5692	58	#include <arpa/inet.h>
15637ed4 RG	59	#include <net/if.h>
	60	#include <netinet/if_ether.h>
	61
	62	#include <errno.h>
	63	#include <nlist.h>
	64	#include <kvm.h>
	65	#include <stdio.h>
	66	#include <paths.h>
	67
	68	extern int errno;
	69
	70	main(argc, argv)
	71	int argc;
	72	char **argv;
	73	{
	74	int ch;
	75
	76	while ((ch = getopt(argc, argv, "adsf")) != EOF)
	77	switch((char)ch) {
	78	case 'a': {
	79	char *mem = 0;
	80
	81	if (argc > 4)
	82	usage();
	83	if (argc == 4) {
	84	mem = argv[3];
	85	}
	86	dump((argc >= 3) ? argv[2] : _PATH_UNIX, mem);
	87	exit(0);
	88	}
	89	case 'd':
	90	if (argc != 3)
	91	usage();
	92	delete(argv[2]);
	93	exit(0);
	94	case 's':
	95	if (argc < 4 \|\| argc > 7)
	96	usage();
	97	exit(set(argc-2, &argv[2]) ? 1 : 0);
	98	case 'f':
	99	if (argc != 3)
	100	usage();
	101	exit (file(argv[2]) ? 1 : 0);
	102	case '?':
	103	default:
	104	usage();
	105	}
	106	if (argc != 2)
	107	usage();
	108	get(argv[1]);
	109	exit(0);
	110	}
	111
	112	/*
	113	* Process a file to set standard arp entries
	114	*/
	115	file(name)
	116	char *name;
	117	{
	118	FILE *fp;
	119	int i, retval;
	120	char line[100], arg[5][50], *args[5];
	121
	122	if ((fp = fopen(name, "r")) == NULL) {
123	fprintf(stderr, "arp: cannot open %s\n", name);
124	exit(1);
125	}
126	args[0] = &arg[0][0];
127	args[1] = &arg[1][0];
128	args[2] = &arg[2][0];
129	args[3] = &arg[3][0];
130	args[4] = &arg[4][0];
131	retval = 0;
132	while(fgets(line, 100, fp) != NULL) {
133	i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2],
134	arg[3], arg[4]);
135	if (i < 2) {
136	fprintf(stderr, "arp: bad line: %s\n", line);
137	retval = 1;
138	continue;
139	}
140	if (set(i, args))
141	retval = 1;
142	}
143	fclose(fp);
144	return (retval);
145	}
146
147	/*
148	* Set an individual arp entry
149	*/
150	set(argc, argv)
151	int argc;
152	char **argv;
153	{
154	struct arpreq ar;
155	struct hostent *hp;
156	struct sockaddr_in *sin;
157	u_char *ea;
158	int s;
159	char host = argv[0], eaddr = argv[1];
160
161	argc -= 2;
162	argv += 2;
163	bzero((caddr_t)&ar, sizeof ar);
164	sin = (struct sockaddr_in *)&ar.arp_pa;
165	sin->sin_family = AF_INET;
166	sin->sin_addr.s_addr = inet_addr(host);
167	if (sin->sin_addr.s_addr == -1) {
168	if (!(hp = gethostbyname(host))) {
169	fprintf(stderr, "arp: %s: ", host);
170	herror((char *)NULL);
171	return (1);
172	}
173	bcopy((char )hp->h_addr, (char )&sin->sin_addr,
174	sizeof sin->sin_addr);
175	}
176	ea = (u_char *)ar.arp_ha.sa_data;
177	if (ether_aton(eaddr, ea))
178	return (1);
179	ar.arp_flags = ATF_PERM;
180	while (argc-- > 0) {
181	if (strncmp(argv[0], "temp", 4) == 0)
182	ar.arp_flags &= ~ATF_PERM;
183	else if (strncmp(argv[0], "pub", 3) == 0)
184	ar.arp_flags \|= ATF_PUBL;
185	else if (strncmp(argv[0], "trail", 5) == 0)
186	ar.arp_flags \|= ATF_USETRAILERS;
187	argv++;
188	}
189
190	s = socket(AF_INET, SOCK_DGRAM, 0);
191	if (s < 0) {
192	perror("arp: socket");
193	exit(1);
194	}
195	if (ioctl(s, SIOCSARP, (caddr_t)&ar) < 0) {
196	perror(host);
197	exit(1);
198	}
199	close(s);
200	return (0);
201	}
202
203	/*
204	* Display an individual arp entry
205	*/
206	get(host)
207	char *host;
208	{
209	struct arpreq ar;
210	struct hostent *hp;
211	struct sockaddr_in *sin;
212	u_char *ea;
213	int s;
15637ed4 RG	214
	215	bzero((caddr_t)&ar, sizeof ar);
	216	ar.arp_pa.sa_family = AF_INET;
	217	sin = (struct sockaddr_in *)&ar.arp_pa;
	218	sin->sin_family = AF_INET;
	219	sin->sin_addr.s_addr = inet_addr(host);
	220	if (sin->sin_addr.s_addr == -1) {
	221	if (!(hp = gethostbyname(host))) {
	222	fprintf(stderr, "arp: %s: ", host);
	223	herror((char *)NULL);
	224	exit(1);
	225	}
	226	bcopy((char )hp->h_addr, (char )&sin->sin_addr,
	227	sizeof sin->sin_addr);
	228	}
	229	s = socket(AF_INET, SOCK_DGRAM, 0);
	230	if (s < 0) {
	231	perror("arp: socket");
	232	exit(1);
	233	}
	234	if (ioctl(s, SIOCGARP, (caddr_t)&ar) < 0) {
	235	if (errno == ENXIO)
	236	printf("%s (%s) -- no entry\n",
	237	host, inet_ntoa(sin->sin_addr));
	238	else
	239	perror("SIOCGARP");
	240	exit(1);
	241	}
	242	close(s);
	243	ea = (u_char *)ar.arp_ha.sa_data;
	244	printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr));
	245	if (ar.arp_flags & ATF_COM)
	246	ether_print(ea);
	247	else
	248	printf("(incomplete)");
	249	if (ar.arp_flags & ATF_PERM)
	250	printf(" permanent");
	251	if (ar.arp_flags & ATF_PUBL)
	252	printf(" published");
	253	if (ar.arp_flags & ATF_USETRAILERS)
	254	printf(" trailers");
	255	printf("\n");
	256	}
	257
	258	/*
	259	* Delete an arp entry
	260	*/
	261	delete(host)
	262	char *host;
	263	{
	264	struct arpreq ar;
	265	struct hostent *hp;
	266	struct sockaddr_in *sin;
	267	int s;
	268
	269	bzero((caddr_t)&ar, sizeof ar);
	270	ar.arp_pa.sa_family = AF_INET;
	271	sin = (struct sockaddr_in *)&ar.arp_pa;
	272	sin->sin_family = AF_INET;
	273	sin->sin_addr.s_addr = inet_addr(host);
	274	if (sin->sin_addr.s_addr == -1) {
	275	if (!(hp = gethostbyname(host))) {
	276	fprintf(stderr, "arp: %s: ", host);
	277	herror((char *)NULL);
278	exit(1);
279	}
280	bcopy((char )hp->h_addr, (char )&sin->sin_addr,
281	sizeof sin->sin_addr);
282	}
283	s = socket(AF_INET, SOCK_DGRAM, 0);
284	if (s < 0) {
285	perror("arp: socket");
286	exit(1);
287	}
288	if (ioctl(s, SIOCDARP, (caddr_t)&ar) < 0) {
289	if (errno == ENXIO)
290	printf("%s (%s) -- no entry\n",
291	host, inet_ntoa(sin->sin_addr));
292	else
293	perror("SIOCDARP");
294	exit(1);
295	}
296	close(s);
297	printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr));
298	}
299
300	struct nlist nl[] = {
301	#define X_ARPTAB 0
302	{ "_arptab" },
303	#define X_ARPTAB_SIZE 1
304	{ "_arptab_size" },
305	{ "" },
306	};
307
308	/*
309	* Dump the entire arp table
310	*/
311	dump(kernel, mem)
312	char kernel, mem;
313	{
314	extern int h_errno;
315	struct arptab *at;
316	struct hostent *hp;
317	int bynumber, mf, arptab_size, sz;
318	char host, malloc();
319	off_t lseek();
320
321	if (kvm_openfiles(kernel, mem, NULL) == -1) {
322	fprintf(stderr, "arp: kvm_openfiles: %s\n", kvm_geterr());
323	exit(1);
324	}
325	if (kvm_nlist(nl) < 0 \|\| nl[X_ARPTAB_SIZE].n_type == 0) {
326	fprintf(stderr, "arp: %s: bad namelist\n", kernel);
327	exit(1);
328	}
329	if (kvm_read((void *)(nl[X_ARPTAB_SIZE].n_value),
330	&arptab_size, sizeof arptab_size) == -1 \|\|
331	arptab_size <= 0 \|\| arptab_size > 1000) {
332	fprintf(stderr, "arp: %s: namelist wrong\n", kernel);
333	exit(1);
334	}
335	sz = arptab_size * sizeof (struct arptab);
336	at = (struct arptab *)malloc((u_int)sz);
337	if (at == NULL) {
338	fputs("arp: can't get memory for arptab.\n", stderr);
339	exit(1);
340	}
341	if (kvm_read((void )(nl[X_ARPTAB].n_value), (char )at, sz) == -1) {
342	perror("arp: error reading arptab");
343	exit(1);
344	}
345	for (bynumber = 0; arptab_size-- > 0; at++) {
346	if (at->at_iaddr.s_addr == 0 \|\| at->at_flags == 0)
347	continue;
348	if (bynumber == 0)
349	hp = gethostbyaddr((caddr_t)&at->at_iaddr,
350	sizeof at->at_iaddr, AF_INET);
351	else
352	hp = 0;
353	if (hp)
354	host = hp->h_name;
355	else {
356	host = "?";
357	if (h_errno == TRY_AGAIN)
358	bynumber = 1;
359	}
360	printf("%s (%s) at ", host, inet_ntoa(at->at_iaddr));
361	if (at->at_flags & ATF_COM)
362	ether_print(at->at_enaddr);
363	else
364	printf("(incomplete)");
365	if (at->at_flags & ATF_PERM)
366	printf(" permanent");
367	if (at->at_flags & ATF_PUBL)
368	printf(" published");
369	if (at->at_flags & ATF_USETRAILERS)
370	printf(" trailers");
371	printf("\n");
372	}
373	}
374
375	ether_print(cp)
376	u_char *cp;
377	{
378	printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]);
379	}
380
381	ether_aton(a, n)
382	char *a;
383	u_char *n;
384	{
385	int i, o[6];
386
387	i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2],
388	&o[3], &o[4], &o[5]);
389	if (i != 6) {
390	fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a);
391	return (1);
392	}
393	for (i=0; i<6; i++)
394	n[i] = o[i];
395	return (0);
396	}
397
398	usage()
399	{
400	printf("usage: arp hostname\n");
401	printf(" arp -a [kernel] [kernel_memory]\n");
402	printf(" arp -d hostname\n");
403	printf(" arp -s hostname ether_addr [temp] [pub] [trail]\n");
404	printf(" arp -f filename\n");
405	exit(1);
406	}