xref: /titanic_51/usr/src/cmd/cmd-inet/usr.sbin/arp.c (revision 96aa4f28c45f26c5cb5f5eb8bf23cb7fc6991d8f)
1 /*
2  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 /*
6  * Copyright (c) 1984 Regents of the University of California.
7  * All rights reserved.
8  *
9  * This code is derived from software contributed to Berkeley by
10  * Sun Microsystems, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. All advertising materials mentioning features or use of this software
21  *    must display the following acknowledgement:
22  *      This product includes software developed by the University of
23  *      California, Berkeley and its contributors.
24  * 4. Neither the name of the University nor the names of its contributors
25  *    may be used to endorse or promote products derived from this software
26  *    without specific prior written permission.
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38  * SUCH DAMAGE.
39  */
40 
41 
42 
43 #pragma ident	"%Z%%M%	%I%	%E% SMI"
44 
45 /*
46  * arp - display, set, and delete arp table entries
47  */
48 
49 #include <stdio.h>
50 #include <sys/types.h>
51 #include <sys/socket.h>
52 #include <netinet/in.h>
53 #include <sys/ioctl.h>
54 #include <errno.h>
55 #include <netdb.h>
56 #include <net/if.h>
57 #include <net/if_arp.h>
58 #include <stdlib.h>
59 #include <unistd.h>
60 #include <string.h>
61 #include <arpa/inet.h>
62 #include <net/if_types.h>
63 #include <net/if_dl.h>
64 
65 static int file(char *);
66 static int set(int, char *[]);
67 static void get(char *);
68 static void delete(char *);
69 static void usage(void);
70 
71 int
72 main(int argc, char *argv[])
73 {
74 	int c, nflags = 0, argsleft;
75 	int n_flag, a_flag, d_flag, f_flag, s_flag;
76 
77 	n_flag = a_flag = d_flag = f_flag = s_flag = 0;
78 
79 #define	CASE(x, y)				\
80 		case x:				\
81 			if (nflags > 0) {	\
82 				usage();	\
83 				exit(1);	\
84 			} else			\
85 				y##_flag = 1;	\
86 				nflags++;	\
87 			break
88 
89 	while ((c = getopt(argc, argv, "nadfs")) != EOF) {
90 		switch (c) {
91 		case '?':
92 			usage();
93 			exit(1);
94 			/* NOTREACHED */
95 			break;
96 		case 'n':
97 			n_flag = 1;
98 			break;
99 		CASE('a', a);
100 		CASE('d', d);
101 		CASE('f', f);
102 		CASE('s', s);
103 		}
104 	}
105 
106 #undef CASE
107 
108 	/*
109 	 * -n only allowed with -a
110 	 */
111 	if (n_flag && !a_flag) {
112 		usage();
113 		exit(1);
114 	}
115 
116 	argsleft = argc - optind;
117 
118 	if (a_flag && (argsleft == 0)) {
119 		/*
120 		 * the easiest way to get the complete arp table
121 		 * is to let netstat, which prints it as part of
122 		 * the MIB statistics, do it.
123 		 */
124 		(void) execl("/usr/bin/netstat", "netstat",
125 		    (n_flag ? "-np" : "-p"),
126 		    "-f", "inet", (char *)0);
127 		exit(1);
128 
129 	} else if (s_flag && (argsleft >= 2)) {
130 		if (set(argsleft, &argv[optind]) != 0)
131 			exit(1);
132 
133 	} else if (d_flag && (argsleft == 1)) {
134 		delete(argv[optind]);
135 
136 	} else if (f_flag && (argsleft == 1)) {
137 		if (file(argv[optind]) != 0)
138 			exit(1);
139 
140 	} else if ((nflags == 0) && (argsleft == 1)) {
141 		get(argv[optind]);
142 
143 	} else {
144 		usage();
145 		exit(1);
146 	}
147 	return (0);
148 }
149 
150 /*
151  * Process a file to set standard arp entries
152  */
153 static int
154 file(char *name)
155 {
156 	/*
157 	 * A line of input can be:
158 	 * <hostname> <macaddr> ["temp"] ["pub"] ["trail"] ["permanent"]
159 	 */
160 #define	MAX_LINE_LEN	(MAXHOSTNAMELEN + \
161 	sizeof (" xx:xx:xx:xx:xx:xx temp pub trail permanent\n"))
162 #define	MIN_ARGS	2
163 #define	MAX_ARGS	5
164 
165 	FILE *fp;
166 	char line[MAX_LINE_LEN];
167 	int retval;
168 
169 	if ((fp = fopen(name, "r")) == NULL) {
170 		(void) fprintf(stderr, "arp: cannot open %s\n", name);
171 		exit(1);
172 	}
173 
174 	retval = 0;
175 	while (fgets(line, MAX_LINE_LEN, fp) != NULL) {
176 		char line_copy[MAX_LINE_LEN];
177 		char *args[MAX_ARGS];
178 		char *start;
179 		int i;
180 
181 		/*
182 		 * Keep a copy of the un-altered line for error
183 		 * reporting.
184 		 */
185 		(void) strlcpy(line_copy, line, MAX_LINE_LEN);
186 
187 		start = line_copy;
188 		for (i = 0; i < MAX_ARGS; i++) {
189 			if ((args[i] = strtok(start, " \t\n")) == NULL)
190 				break;
191 
192 			start = NULL;
193 		}
194 
195 		if (i < MIN_ARGS) {
196 			(void) fprintf(stderr, "arp: bad line: %s\n",
197 			    line);
198 			retval = 1;
199 			continue;
200 		}
201 
202 		if (set(i, args) != 0)
203 			retval = 1;
204 	}
205 
206 #undef	MAX_LINE_LEN
207 #undef	MIN_ARGS
208 #undef	MAX_ARGS
209 
210 	(void) fclose(fp);
211 	return (retval);
212 }
213 
214 /*
215  * Set an individual arp entry
216  */
217 static int
218 set(int argc, char *argv[])
219 {
220 	struct xarpreq ar;
221 	struct hostent *hp;
222 	struct sockaddr_in *sin;
223 	uchar_t *ea;
224 	int s;
225 	char *host = argv[0], *eaddr = argv[1];
226 
227 	argc -= 2;
228 	argv += 2;
229 	(void) memset(&ar, 0, sizeof (ar));
230 	sin = (struct sockaddr_in *)&ar.xarp_pa;
231 	sin->sin_family = AF_INET;
232 	sin->sin_addr.s_addr = inet_addr(host);
233 	if (sin->sin_addr.s_addr == (in_addr_t)-1) {
234 		hp = gethostbyname(host);
235 		if (hp == NULL) {
236 			(void) fprintf(stderr, "arp: %s: unknown host\n",
237 			    host);
238 			return (1);
239 		}
240 		(void) memcpy(&sin->sin_addr, hp->h_addr,
241 		    sizeof (sin->sin_addr));
242 	}
243 	ea = _link_aton(eaddr, &s);
244 	if (ea == NULL) {
245 		if (s == -1) {
246 			(void) fprintf(stderr,
247 			    "arp: invalid link layer address '%s'\n", eaddr);
248 			return (1);
249 		}
250 		perror("arp: nomem");
251 		exit(1);
252 	}
253 	ar.xarp_ha.sdl_alen = s;
254 	(void) memcpy(LLADDR(&ar.xarp_ha), ea, ar.xarp_ha.sdl_alen);
255 	free(ea);
256 	ar.xarp_ha.sdl_family = AF_LINK;
257 	ar.xarp_flags = ATF_PERM;
258 	while (argc-- > 0) {
259 		if (strncmp(argv[0], "temp", 4) == 0) {
260 			ar.xarp_flags &= ~ATF_PERM;
261 		} else if (strncmp(argv[0], "pub", 3) == 0) {
262 			ar.xarp_flags |= ATF_PUBL;
263 		} else if (strncmp(argv[0], "trail", 5) == 0) {
264 			ar.xarp_flags |= ATF_USETRAILERS;
265 		} else if (strcmp(argv[0], "permanent") == 0) {
266 			ar.xarp_flags |= ATF_AUTHORITY;
267 		} else {
268 			(void) fprintf(stderr,
269 			    "arp: unknown keyword '%s'\n", argv[0]);
270 			return (1);
271 		}
272 		argv++;
273 	}
274 
275 	if ((ar.xarp_flags & (ATF_PERM|ATF_AUTHORITY)) == ATF_AUTHORITY) {
276 		(void) fprintf(stderr, "arp: 'temp' and 'permanent' flags are "
277 		    "not usable together.\n");
278 		return (1);
279 	}
280 
281 	s = socket(AF_INET, SOCK_DGRAM, 0);
282 	if (s < 0) {
283 		perror("arp: socket");
284 		exit(1);
285 	}
286 	if (ioctl(s, SIOCSXARP, (caddr_t)&ar) < 0) {
287 		perror(host);
288 		exit(1);
289 	}
290 	(void) close(s);
291 	return (0);
292 }
293 
294 /*
295  * Display an individual arp entry
296  */
297 static void
298 get(char *host)
299 {
300 	struct xarpreq ar;
301 	struct hostent *hp;
302 	struct sockaddr_in *sin;
303 	uchar_t *ea;
304 	int s;
305 	char *str = NULL;
306 
307 	(void) memset(&ar, 0, sizeof (ar));
308 	sin = (struct sockaddr_in *)&ar.xarp_pa;
309 	sin->sin_family = AF_INET;
310 	sin->sin_addr.s_addr = inet_addr(host);
311 	if (sin->sin_addr.s_addr == (in_addr_t)-1) {
312 		hp = gethostbyname(host);
313 		if (hp == NULL) {
314 			(void) fprintf(stderr, "arp: %s: unknown host\n",
315 			    host);
316 			exit(1);
317 		}
318 		(void) memcpy(&sin->sin_addr, hp->h_addr,
319 		    sizeof (sin->sin_addr));
320 	}
321 	s = socket(AF_INET, SOCK_DGRAM, 0);
322 	if (s < 0) {
323 		perror("arp: socket");
324 		exit(1);
325 	}
326 	ar.xarp_ha.sdl_family = AF_LINK;
327 	if (ioctl(s, SIOCGXARP, (caddr_t)&ar) < 0) {
328 		if (errno == ENXIO)
329 			(void) printf("%s (%s) -- no entry\n",
330 			    host, inet_ntoa(sin->sin_addr));
331 		else
332 			perror("SIOCGXARP");
333 		exit(1);
334 	}
335 	(void) close(s);
336 	ea = (uchar_t *)LLADDR(&ar.xarp_ha);
337 	if (ar.xarp_flags & ATF_COM) {
338 		str = _link_ntoa(ea, str, ar.xarp_ha.sdl_alen, IFT_OTHER);
339 		if (str != NULL) {
340 			(void) printf("%s (%s) at %s", host,
341 			    inet_ntoa(sin->sin_addr), str);
342 			free(str);
343 		} else {
344 			perror("arp: nomem");
345 			exit(1);
346 		}
347 	} else {
348 		(void) printf("%s (%s) at (incomplete)", host,
349 		    inet_ntoa(sin->sin_addr));
350 	}
351 	if (!(ar.xarp_flags & ATF_PERM))
352 		(void) printf(" temp");
353 	if (ar.xarp_flags & ATF_PUBL)
354 		(void) printf(" pub");
355 	if (ar.xarp_flags & ATF_USETRAILERS)
356 		(void) printf(" trail");
357 	if (ar.xarp_flags & ATF_AUTHORITY)
358 		(void) printf(" permanent");
359 	(void) printf("\n");
360 }
361 
362 /*
363  * Delete an arp entry
364  */
365 static void
366 delete(char *host)
367 {
368 	struct xarpreq ar;
369 	struct hostent *hp;
370 	struct sockaddr_in *sin;
371 	int s;
372 
373 	(void) memset(&ar, 0, sizeof (ar));
374 	sin = (struct sockaddr_in *)&ar.xarp_pa;
375 	sin->sin_family = AF_INET;
376 	sin->sin_addr.s_addr = inet_addr(host);
377 	if (sin->sin_addr.s_addr == (in_addr_t)-1) {
378 		hp = gethostbyname(host);
379 		if (hp == NULL) {
380 			(void) fprintf(stderr, "arp: %s: unknown host\n",
381 			    host);
382 			exit(1);
383 		}
384 		(void) memcpy(&sin->sin_addr, hp->h_addr,
385 		    sizeof (sin->sin_addr));
386 	}
387 	s = socket(AF_INET, SOCK_DGRAM, 0);
388 	if (s < 0) {
389 		perror("arp: socket");
390 		exit(1);
391 	}
392 	ar.xarp_ha.sdl_family = AF_LINK;
393 	if (ioctl(s, SIOCDXARP, (caddr_t)&ar) < 0) {
394 		if (errno == ENXIO)
395 			(void) printf("%s (%s) -- no entry\n",
396 			    host, inet_ntoa(sin->sin_addr));
397 		else
398 			perror("SIOCDXARP");
399 		exit(1);
400 	}
401 	(void) close(s);
402 	(void) printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr));
403 }
404 
405 static void
406 usage(void)
407 {
408 	(void) printf("Usage: arp hostname\n");
409 	(void) printf("       arp -a [-n]\n");
410 	(void) printf("       arp -d hostname\n");
411 	(void) printf("       arp -s hostname ether_addr "
412 	    "[temp] [pub] [trail] [permanent]\n");
413 	(void) printf("       arp -f filename\n");
414 }
415