1 /*
2 * Copyright (c) 1984, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Sun Microsystems, Inc.
7 *
8 * %sccs.include.redist.c%
9 */
10
11 #ifndef lint
12 static char copyright[] =
13 "@(#) Copyright (c) 1984, 1993\n\
14 The Regents of the University of California. All rights reserved.\n";
15 #endif /* not lint */
16
17 #ifndef lint
18 static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 04/28/95";
19 #endif /* not lint */
20
21 /*
22 * arp - display, set, and delete arp table entries
23 */
24
25
26 #include <sys/param.h>
27 #include <sys/file.h>
28 #include <sys/socket.h>
29 #include <sys/sysctl.h>
30
31 #include <net/if.h>
32 #include <net/if_dl.h>
33 #include <net/if_types.h>
34 #include <net/route.h>
35
36 #include <netinet/in.h>
37 #include <netinet/if_ether.h>
38
39 #include <arpa/inet.h>
40
41 #include <err.h>
42 #include <errno.h>
43 #include <netdb.h>
44 #include <nlist.h>
45 #include <paths.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50
51 static int pid;
52 static int nflag;
53 static int s = -1;
54
55 int delete __P((char *, char *));
56 void dump __P((u_long));
57 int ether_aton __P((char *, u_char *));
58 void ether_print __P((u_char *));
59 int file __P((char *));
60 void get __P((char *));
61 void getsocket __P((void));
62 int rtmsg __P((int));
63 int set __P((int, char **));
64 void usage __P((void));
65
66 int
main(argc,argv)67 main(argc, argv)
68 int argc;
69 char **argv;
70 {
71 int ch;
72
73 pid = getpid();
74 while ((ch = getopt(argc, argv, "ands")) != EOF)
75 switch((char)ch) {
76 case 'a':
77 dump(0);
78 exit(0);
79 case 'd':
80 if (argc < 3 || argc > 4)
81 usage();
82 delete(argv[2], argv[3]);
83 exit(0);
84 case 'n':
85 nflag = 1;
86 continue;
87 case 's':
88 if (argc < 4 || argc > 7)
89 usage();
90 exit(set(argc-2, &argv[2]) ? 1 : 0);
91 case '?':
92 default:
93 usage();
94 }
95 if (argc != 2)
96 usage();
97 get(argv[1]);
98 return (0);
99 }
100
101 /*
102 * Process a file to set standard arp entries
103 */
104 int
file(name)105 file(name)
106 char *name;
107 {
108 FILE *fp;
109 int i, retval;
110 char line[100], arg[5][50], *args[5];
111
112 if ((fp = fopen(name, "r")) == NULL) {
113 fprintf(stderr, "arp: cannot open %s\n", name);
114 exit(1);
115 }
116 args[0] = &arg[0][0];
117 args[1] = &arg[1][0];
118 args[2] = &arg[2][0];
119 args[3] = &arg[3][0];
120 args[4] = &arg[4][0];
121 retval = 0;
122 while(fgets(line, 100, fp) != NULL) {
123 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2],
124 arg[3], arg[4]);
125 if (i < 2) {
126 fprintf(stderr, "arp: bad line: %s\n", line);
127 retval = 1;
128 continue;
129 }
130 if (set(i, args))
131 retval = 1;
132 }
133 fclose(fp);
134 return (retval);
135 }
136
137 void
getsocket()138 getsocket() {
139 if (s < 0) {
140 s = socket(PF_ROUTE, SOCK_RAW, 0);
141 if (s < 0) {
142 perror("arp: socket");
143 exit(1);
144 }
145 }
146 }
147
148 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
149 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
150 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
151 int expire_time, flags, export_only, doing_proxy, found_entry;
152 struct {
153 struct rt_msghdr m_rtm;
154 char m_space[512];
155 } m_rtmsg;
156
157 /*
158 * Set an individual arp entry
159 */
160 int
set(argc,argv)161 set(argc, argv)
162 int argc;
163 char **argv;
164 {
165 struct hostent *hp;
166 register struct sockaddr_inarp *sin = &sin_m;
167 register struct sockaddr_dl *sdl;
168 register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
169 u_char *ea;
170 char *host = argv[0], *eaddr = argv[1];
171
172 getsocket();
173 argc -= 2;
174 argv += 2;
175 sdl_m = blank_sdl;
176 sin_m = blank_sin;
177 sin->sin_addr.s_addr = inet_addr(host);
178 if (sin->sin_addr.s_addr == -1) {
179 if (!(hp = gethostbyname(host))) {
180 fprintf(stderr, "arp: %s: ", host);
181 herror((char *)NULL);
182 return (1);
183 }
184 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr,
185 sizeof sin->sin_addr);
186 }
187 ea = (u_char *)LLADDR(&sdl_m);
188 if (ether_aton(eaddr, ea) == 0)
189 sdl_m.sdl_alen = 6;
190 doing_proxy = flags = export_only = expire_time = 0;
191 while (argc-- > 0) {
192 if (strncmp(argv[0], "temp", 4) == 0) {
193 struct timeval time;
194 gettimeofday(&time, 0);
195 expire_time = time.tv_sec + 20 * 60;
196 }
197 else if (strncmp(argv[0], "pub", 3) == 0) {
198 flags |= RTF_ANNOUNCE;
199 doing_proxy = SIN_PROXY;
200 } else if (strncmp(argv[0], "trail", 5) == 0) {
201 printf("%s: Sending trailers is no longer supported\n",
202 host);
203 }
204 argv++;
205 }
206 tryagain:
207 if (rtmsg(RTM_GET) < 0) {
208 perror(host);
209 return (1);
210 }
211 sin = (struct sockaddr_inarp *)(rtm + 1);
212 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
213 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
214 if (sdl->sdl_family == AF_LINK &&
215 (rtm->rtm_flags & RTF_LLINFO) &&
216 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
217 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
218 case IFT_ISO88024: case IFT_ISO88025:
219 goto overwrite;
220 }
221 if (doing_proxy == 0) {
222 printf("set: can only proxy for %s\n", host);
223 return (1);
224 }
225 if (sin_m.sin_other & SIN_PROXY) {
226 printf("set: proxy entry exists for non 802 device\n");
227 return(1);
228 }
229 sin_m.sin_other = SIN_PROXY;
230 export_only = 1;
231 goto tryagain;
232 }
233 overwrite:
234 if (sdl->sdl_family != AF_LINK) {
235 printf("cannot intuit interface index and type for %s\n", host);
236 return (1);
237 }
238 sdl_m.sdl_type = sdl->sdl_type;
239 sdl_m.sdl_index = sdl->sdl_index;
240 return (rtmsg(RTM_ADD));
241 }
242
243 /*
244 * Display an individual arp entry
245 */
246 void
get(host)247 get(host)
248 char *host;
249 {
250 struct hostent *hp;
251 struct sockaddr_inarp *sin = &sin_m;
252
253 sin_m = blank_sin;
254 sin->sin_addr.s_addr = inet_addr(host);
255 if (sin->sin_addr.s_addr == -1) {
256 if (!(hp = gethostbyname(host))) {
257 fprintf(stderr, "arp: %s: ", host);
258 herror((char *)NULL);
259 exit(1);
260 }
261 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr,
262 sizeof sin->sin_addr);
263 }
264 dump(sin->sin_addr.s_addr);
265 if (found_entry == 0) {
266 printf("%s (%s) -- no entry\n",
267 host, inet_ntoa(sin->sin_addr));
268 exit(1);
269 }
270 }
271
272 /*
273 * Delete an arp entry
274 */
275 int
delete(host,info)276 delete(host, info)
277 char *host;
278 char *info;
279 {
280 struct hostent *hp;
281 register struct sockaddr_inarp *sin = &sin_m;
282 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
283 struct sockaddr_dl *sdl;
284
285 if (info && strncmp(info, "pro", 3) )
286 export_only = 1;
287 getsocket();
288 sin_m = blank_sin;
289 sin->sin_addr.s_addr = inet_addr(host);
290 if (sin->sin_addr.s_addr == -1) {
291 if (!(hp = gethostbyname(host))) {
292 fprintf(stderr, "arp: %s: ", host);
293 herror((char *)NULL);
294 return (1);
295 }
296 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr,
297 sizeof sin->sin_addr);
298 }
299 tryagain:
300 if (rtmsg(RTM_GET) < 0) {
301 perror(host);
302 return (1);
303 }
304 sin = (struct sockaddr_inarp *)(rtm + 1);
305 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
306 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
307 if (sdl->sdl_family == AF_LINK &&
308 (rtm->rtm_flags & RTF_LLINFO) &&
309 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
310 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
311 case IFT_ISO88024: case IFT_ISO88025:
312 goto delete;
313 }
314 }
315 if (sin_m.sin_other & SIN_PROXY) {
316 fprintf(stderr, "delete: can't locate %s\n",host);
317 return (1);
318 } else {
319 sin_m.sin_other = SIN_PROXY;
320 goto tryagain;
321 }
322 delete:
323 if (sdl->sdl_family != AF_LINK) {
324 printf("cannot locate %s\n", host);
325 return (1);
326 }
327 if (rtmsg(RTM_DELETE))
328 return (1);
329 printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr));
330 return (0);
331 }
332
333 /*
334 * Dump the entire arp table
335 */
336 void
dump(addr)337 dump(addr)
338 u_long addr;
339 {
340 int mib[6];
341 size_t needed;
342 char *host, *lim, *buf, *next;
343 struct rt_msghdr *rtm;
344 struct sockaddr_inarp *sin;
345 struct sockaddr_dl *sdl;
346 extern int h_errno;
347 struct hostent *hp;
348
349 mib[0] = CTL_NET;
350 mib[1] = PF_ROUTE;
351 mib[2] = 0;
352 mib[3] = AF_INET;
353 mib[4] = NET_RT_FLAGS;
354 mib[5] = RTF_LLINFO;
355 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
356 err(1, "route-sysctl-estimate");
357 if ((buf = malloc(needed)) == NULL)
358 err(1, "malloc");
359 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
360 err(1, "actual retrieval of routing table");
361 lim = buf + needed;
362 for (next = buf; next < lim; next += rtm->rtm_msglen) {
363 rtm = (struct rt_msghdr *)next;
364 sin = (struct sockaddr_inarp *)(rtm + 1);
365 sdl = (struct sockaddr_dl *)(sin + 1);
366 if (addr) {
367 if (addr != sin->sin_addr.s_addr)
368 continue;
369 found_entry = 1;
370 }
371 if (nflag == 0)
372 hp = gethostbyaddr((caddr_t)&(sin->sin_addr),
373 sizeof sin->sin_addr, AF_INET);
374 else
375 hp = 0;
376 if (hp)
377 host = hp->h_name;
378 else {
379 host = "?";
380 if (h_errno == TRY_AGAIN)
381 nflag = 1;
382 }
383 printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr));
384 if (sdl->sdl_alen)
385 ether_print((u_char *)LLADDR(sdl));
386 else
387 printf("(incomplete)");
388 if (rtm->rtm_rmx.rmx_expire == 0)
389 printf(" permanent");
390 if (sin->sin_other & SIN_PROXY)
391 printf(" published (proxy only)");
392 if (rtm->rtm_addrs & RTA_NETMASK) {
393 sin = (struct sockaddr_inarp *)
394 (sdl->sdl_len + (char *)sdl);
395 if (sin->sin_addr.s_addr == 0xffffffff)
396 printf(" published");
397 if (sin->sin_len != 8)
398 printf("(wierd)");
399 }
400 printf("\n");
401 }
402 }
403
404 void
ether_print(cp)405 ether_print(cp)
406 u_char *cp;
407 {
408 printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]);
409 }
410
411 int
ether_aton(a,n)412 ether_aton(a, n)
413 char *a;
414 u_char *n;
415 {
416 int i, o[6];
417
418 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2],
419 &o[3], &o[4], &o[5]);
420 if (i != 6) {
421 fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a);
422 return (1);
423 }
424 for (i=0; i<6; i++)
425 n[i] = o[i];
426 return (0);
427 }
428
429 void
usage()430 usage()
431 {
432 printf("usage: arp hostname\n");
433 printf(" arp -a [kernel] [kernel_memory]\n");
434 printf(" arp -d hostname\n");
435 printf(" arp -s hostname ether_addr [temp] [pub]\n");
436 printf(" arp -f filename\n");
437 exit(1);
438 }
439
440 int
rtmsg(cmd)441 rtmsg(cmd)
442 int cmd;
443 {
444 static int seq;
445 int rlen;
446 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
447 register char *cp = m_rtmsg.m_space;
448 register int l;
449
450 errno = 0;
451 if (cmd == RTM_DELETE)
452 goto doit;
453 bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
454 rtm->rtm_flags = flags;
455 rtm->rtm_version = RTM_VERSION;
456
457 switch (cmd) {
458 default:
459 fprintf(stderr, "arp: internal wrong cmd\n");
460 exit(1);
461 case RTM_ADD:
462 rtm->rtm_addrs |= RTA_GATEWAY;
463 rtm->rtm_rmx.rmx_expire = expire_time;
464 rtm->rtm_inits = RTV_EXPIRE;
465 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
466 sin_m.sin_other = 0;
467 if (doing_proxy) {
468 if (export_only)
469 sin_m.sin_other = SIN_PROXY;
470 else {
471 rtm->rtm_addrs |= RTA_NETMASK;
472 rtm->rtm_flags &= ~RTF_HOST;
473 }
474 }
475 /* FALLTHROUGH */
476 case RTM_GET:
477 rtm->rtm_addrs |= RTA_DST;
478 }
479 #define NEXTADDR(w, s) \
480 if (rtm->rtm_addrs & (w)) { \
481 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);}
482
483 NEXTADDR(RTA_DST, sin_m);
484 NEXTADDR(RTA_GATEWAY, sdl_m);
485 NEXTADDR(RTA_NETMASK, so_mask);
486
487 rtm->rtm_msglen = cp - (char *)&m_rtmsg;
488 doit:
489 l = rtm->rtm_msglen;
490 rtm->rtm_seq = ++seq;
491 rtm->rtm_type = cmd;
492 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
493 if (errno != ESRCH || cmd != RTM_DELETE) {
494 perror("writing to routing socket");
495 return (-1);
496 }
497 }
498 do {
499 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
500 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
501 if (l < 0)
502 (void) fprintf(stderr, "arp: read from routing socket: %s\n",
503 strerror(errno));
504 return (0);
505 }
506