arp.c revision 1.17
1 /* $NetBSD: arp.c,v 1.17 1997/03/15 18:37:27 is Exp $ */ 2 3 /* 4 * Copyright (c) 1984, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Sun Microsystems, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #ifndef lint 40 static char copyright[] = 41 "@(#) Copyright (c) 1984, 1993\n\ 42 The Regents of the University of California. All rights reserved.\n"; 43 #endif /* not lint */ 44 45 #ifndef lint 46 /* static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; */ 47 static char *rcsid = "$NetBSD: arp.c,v 1.17 1997/03/15 18:37:27 is Exp $"; 48 #endif /* not lint */ 49 50 /* 51 * arp - display, set, and delete arp table entries 52 */ 53 54 #include <sys/param.h> 55 #include <sys/file.h> 56 #include <sys/socket.h> 57 #include <sys/sysctl.h> 58 59 #include <net/if.h> 60 #include <net/if_dl.h> 61 #include <net/if_ether.h> 62 #include <net/if_types.h> 63 #include <net/route.h> 64 #include <netinet/in.h> 65 #include <netinet/if_inarp.h> 66 #include <arpa/inet.h> 67 68 #include <err.h> 69 #include <errno.h> 70 #include <netdb.h> 71 #include <nlist.h> 72 #include <paths.h> 73 #include <stdio.h> 74 #include <stdlib.h> 75 #include <string.h> 76 #include <unistd.h> 77 78 int delete __P((const char *, const char *)); 79 void dump __P((u_long)); 80 void sdl_print __P((const struct sockaddr_dl *)); 81 int atosdl __P((const char *s, struct sockaddr_dl *sdl)); 82 int file __P((char *)); 83 void get __P((const char *)); 84 int getinetaddr __P((const char *, struct in_addr *)); 85 void getsocket __P((void)); 86 int rtmsg __P((int)); 87 int set __P((int, char **)); 88 void usage __P((void)); 89 90 static int pid; 91 static int nflag; 92 static int s = -1; 93 94 int delete __P((const char *, const char *)); 95 void dump __P((u_long)); 96 void ether_print __P((const u_char *)); 97 int file __P((char *)); 98 void get __P((const char *)); 99 int getinetaddr __P((const char *, struct in_addr *)); 100 void getsocket __P((void)); 101 int rtmsg __P((int)); 102 int set __P((int, char **)); 103 void usage __P((void)); 104 105 int 106 main(argc, argv) 107 int argc; 108 char **argv; 109 { 110 int ch; 111 int op = 0; 112 113 pid = getpid(); 114 115 while ((ch = getopt(argc, argv, "andsf")) != -1) 116 switch((char)ch) { 117 case 'a': 118 case 'd': 119 case 's': 120 case 'f': 121 if (op) 122 usage(); 123 op = ch; 124 break; 125 case 'n': 126 nflag = 1; 127 break; 128 default: 129 usage(); 130 } 131 argc -= optind; 132 argv += optind; 133 134 switch((char)op) { 135 case 'a': 136 dump(0); 137 break; 138 case 'd': 139 if (argc < 1 || argc > 2) 140 usage(); 141 (void)delete(argv[0], argv[1]); 142 break; 143 case 's': 144 if (argc < 2 || argc > 5) 145 usage(); 146 return (set(argc, argv) ? 1 : 0); 147 case 'f': 148 if (argc != 1) 149 usage(); 150 return (file(argv[0])); 151 default: 152 if (argc != 1) 153 usage(); 154 get(argv[0]); 155 break; 156 } 157 return (0); 158 } 159 160 /* 161 * Process a file to set standard arp entries 162 */ 163 int 164 file(name) 165 char *name; 166 { 167 char line[100], arg[5][50], *args[5]; 168 int i, retval; 169 FILE *fp; 170 171 if ((fp = fopen(name, "r")) == NULL) 172 err(1, "cannot open %s", name); 173 args[0] = &arg[0][0]; 174 args[1] = &arg[1][0]; 175 args[2] = &arg[2][0]; 176 args[3] = &arg[3][0]; 177 args[4] = &arg[4][0]; 178 retval = 0; 179 while (fgets(line, 100, fp) != NULL) { 180 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 181 arg[3], arg[4]); 182 if (i < 2) { 183 warnx("bad line: %s", line); 184 retval = 1; 185 continue; 186 } 187 if (set(i, args)) 188 retval = 1; 189 } 190 fclose(fp); 191 return (retval); 192 } 193 194 void 195 getsocket() 196 { 197 if (s >= 0) 198 return; 199 s = socket(PF_ROUTE, SOCK_RAW, 0); 200 if (s < 0) 201 err(1, "socket"); 202 } 203 204 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 205 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 206 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 207 int expire_time, flags, export_only, doing_proxy, found_entry; 208 struct { 209 struct rt_msghdr m_rtm; 210 char m_space[512]; 211 } m_rtmsg; 212 213 /* 214 * Set an individual arp entry 215 */ 216 int 217 set(argc, argv) 218 int argc; 219 char **argv; 220 { 221 register struct sockaddr_inarp *sin; 222 register struct sockaddr_dl *sdl; 223 register struct rt_msghdr *rtm; 224 struct ether_addr *ea; 225 char *host = argv[0], *eaddr; 226 227 sin = &sin_m; 228 rtm = &(m_rtmsg.m_rtm); 229 eaddr = argv[1]; 230 231 getsocket(); 232 argc -= 2; 233 argv += 2; 234 sdl_m = blank_sdl; /* struct copy */ 235 sin_m = blank_sin; /* struct copy */ 236 if (getinetaddr(host, &sin->sin_addr) == -1) 237 return (1); 238 if (atosdl(eaddr, &sdl_m)) 239 warnx("invalid link-level address '%s'", eaddr); 240 doing_proxy = flags = export_only = expire_time = 0; 241 while (argc-- > 0) { 242 if (strncmp(argv[0], "temp", 4) == 0) { 243 struct timeval time; 244 (void)gettimeofday(&time, 0); 245 expire_time = time.tv_sec + 20 * 60; 246 } 247 else if (strncmp(argv[0], "pub", 3) == 0) { 248 flags |= RTF_ANNOUNCE; 249 doing_proxy = SIN_PROXY; 250 } else if (strncmp(argv[0], "trail", 5) == 0) { 251 (void)printf( 252 "%s: Sending trailers is no longer supported\n", 253 host); 254 } 255 argv++; 256 } 257 tryagain: 258 if (rtmsg(RTM_GET) < 0) { 259 warn("%s", host); 260 return (1); 261 } 262 sin = (struct sockaddr_inarp *)(rtm + 1); 263 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 264 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 265 if (sdl->sdl_family == AF_LINK && 266 (rtm->rtm_flags & RTF_LLINFO) && 267 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 268 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 269 case IFT_ISO88024: case IFT_ISO88025: 270 goto overwrite; 271 } 272 if (doing_proxy == 0) { 273 (void)printf("set: can only proxy for %s\n", host); 274 return (1); 275 } 276 if (sin_m.sin_other & SIN_PROXY) { 277 (void)printf( 278 "set: proxy entry exists for non 802 device\n"); 279 return (1); 280 } 281 sin_m.sin_other = SIN_PROXY; 282 export_only = 1; 283 goto tryagain; 284 } 285 overwrite: 286 if (sdl->sdl_family != AF_LINK) { 287 (void)printf("cannot intuit interface index and type for %s\n", 288 host); 289 return (1); 290 } 291 sdl_m.sdl_type = sdl->sdl_type; 292 sdl_m.sdl_index = sdl->sdl_index; 293 return (rtmsg(RTM_ADD)); 294 } 295 296 /* 297 * Display an individual arp entry 298 */ 299 void 300 get(host) 301 const char *host; 302 { 303 struct sockaddr_inarp *sin; 304 305 sin = &sin_m; 306 sin_m = blank_sin; /* struct copy */ 307 if (getinetaddr(host, &sin->sin_addr) == -1) 308 exit(1); 309 dump(sin->sin_addr.s_addr); 310 if (found_entry == 0) { 311 (void)printf("%s (%s) -- no entry\n", host, 312 inet_ntoa(sin->sin_addr)); 313 exit(1); 314 } 315 } 316 317 /* 318 * Delete an arp entry 319 */ 320 int 321 delete(host, info) 322 const char *host; 323 const char *info; 324 { 325 register struct sockaddr_inarp *sin; 326 register struct rt_msghdr *rtm; 327 struct sockaddr_dl *sdl; 328 329 sin = &sin_m; 330 rtm = &m_rtmsg.m_rtm; 331 332 if (info && strncmp(info, "pro", 3) ) 333 export_only = 1; 334 getsocket(); 335 sin_m = blank_sin; /* struct copy */ 336 if (getinetaddr(host, &sin->sin_addr) == -1) 337 return (1); 338 tryagain: 339 if (rtmsg(RTM_GET) < 0) { 340 warn("%s", host); 341 return (1); 342 } 343 sin = (struct sockaddr_inarp *)(rtm + 1); 344 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 345 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 346 if (sdl->sdl_family == AF_LINK && 347 (rtm->rtm_flags & RTF_LLINFO) && 348 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 349 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 350 case IFT_ISO88024: case IFT_ISO88025: 351 goto delete; 352 } 353 } 354 if (sin_m.sin_other & SIN_PROXY) { 355 warnx("delete: can't locate %s", host); 356 return (1); 357 } else { 358 sin_m.sin_other = SIN_PROXY; 359 goto tryagain; 360 } 361 delete: 362 if (sdl->sdl_family != AF_LINK) { 363 (void)printf("cannot locate %s\n", host); 364 return (1); 365 } 366 if (rtmsg(RTM_DELETE)) 367 return (1); 368 (void)printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 369 return (0); 370 } 371 372 /* 373 * Dump the entire arp table 374 */ 375 void 376 dump(addr) 377 u_long addr; 378 { 379 int mib[6]; 380 size_t needed; 381 char *host, *lim, *buf, *next; 382 struct rt_msghdr *rtm; 383 struct sockaddr_inarp *sin; 384 struct sockaddr_dl *sdl; 385 extern int h_errno; 386 struct hostent *hp; 387 388 mib[0] = CTL_NET; 389 mib[1] = PF_ROUTE; 390 mib[2] = 0; 391 mib[3] = AF_INET; 392 mib[4] = NET_RT_FLAGS; 393 mib[5] = RTF_LLINFO; 394 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 395 err(1, "route-sysctl-estimate"); 396 if ((buf = malloc(needed)) == NULL) 397 err(1, "malloc"); 398 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 399 err(1, "actual retrieval of routing table"); 400 lim = buf + needed; 401 for (next = buf; next < lim; next += rtm->rtm_msglen) { 402 rtm = (struct rt_msghdr *)next; 403 sin = (struct sockaddr_inarp *)(rtm + 1); 404 sdl = (struct sockaddr_dl *)(sin + 1); 405 if (addr) { 406 if (addr != sin->sin_addr.s_addr) 407 continue; 408 found_entry = 1; 409 } 410 if (nflag == 0) 411 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 412 sizeof sin->sin_addr, AF_INET); 413 else 414 hp = 0; 415 if (hp) 416 host = hp->h_name; 417 else { 418 host = "?"; 419 if (h_errno == TRY_AGAIN) 420 nflag = 1; 421 } 422 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 423 if (sdl->sdl_alen) 424 sdl_print(sdl); 425 else 426 (void)printf("(incomplete)"); 427 if (rtm->rtm_rmx.rmx_expire == 0) 428 (void)printf(" permanent"); 429 if (sin->sin_other & SIN_PROXY) 430 (void)printf(" published (proxy only)"); 431 if (rtm->rtm_addrs & RTA_NETMASK) { 432 sin = (struct sockaddr_inarp *) 433 (sdl->sdl_len + (char *)sdl); 434 if (sin->sin_addr.s_addr == 0xffffffff) 435 (void)printf(" published"); 436 if (sin->sin_len != 8) 437 (void)printf("(wierd)"); 438 } 439 (void)printf("\n"); 440 } 441 } 442 443 void 444 sdl_print(sdl) 445 const struct sockaddr_dl *sdl; 446 { 447 int i; 448 u_int8_t *p; 449 450 i = sdl->sdl_alen; 451 p = LLADDR(sdl); 452 453 (void)printf("%x", *p); 454 while (--i > 0) 455 (void)printf(":%x", *++p); 456 } 457 458 int 459 atosdl(s, sdl) 460 const char *s; 461 struct sockaddr_dl *sdl; 462 { 463 int i; 464 long b; 465 caddr_t endp; 466 caddr_t p; 467 char *t, *r; 468 469 p = LLADDR(sdl); 470 endp = ((caddr_t)sdl) + sdl->sdl_len; 471 i = 0; 472 473 b = strtol(s, &t, 16); 474 if (t == s) 475 return 1; 476 477 *p++ = b; 478 ++i; 479 while ((p < endp) && (*t++ == ':')) { 480 b = strtol(t, &r, 16); 481 if (r == t) 482 break; 483 *p++ = b; 484 ++i; 485 t = r; 486 } 487 sdl->sdl_alen = i; 488 489 return 0; 490 } 491 492 void 493 usage() 494 { 495 (void)fprintf(stderr, "usage: arp [-n] hostname\n"); 496 (void)fprintf(stderr, "usage: arp [-n] -a\n"); 497 (void)fprintf(stderr, "usage: arp -d hostname\n"); 498 (void)fprintf(stderr, 499 "usage: arp -s hostname ether_addr [temp] [pub]\n"); 500 (void)fprintf(stderr, "usage: arp -f filename\n"); 501 exit(1); 502 } 503 504 int 505 rtmsg(cmd) 506 int cmd; 507 { 508 static int seq; 509 int rlen; 510 register struct rt_msghdr *rtm; 511 register char *cp; 512 register int l; 513 514 rtm = &m_rtmsg.m_rtm; 515 cp = m_rtmsg.m_space; 516 errno = 0; 517 518 if (cmd == RTM_DELETE) 519 goto doit; 520 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 521 rtm->rtm_flags = flags; 522 rtm->rtm_version = RTM_VERSION; 523 524 switch (cmd) { 525 default: 526 errx(1, "internal wrong cmd"); 527 /*NOTREACHED*/ 528 case RTM_ADD: 529 rtm->rtm_addrs |= RTA_GATEWAY; 530 rtm->rtm_rmx.rmx_expire = expire_time; 531 rtm->rtm_inits = RTV_EXPIRE; 532 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 533 sin_m.sin_other = 0; 534 if (doing_proxy) { 535 if (export_only) 536 sin_m.sin_other = SIN_PROXY; 537 else { 538 rtm->rtm_addrs |= RTA_NETMASK; 539 rtm->rtm_flags &= ~RTF_HOST; 540 } 541 } 542 /* FALLTHROUGH */ 543 case RTM_GET: 544 rtm->rtm_addrs |= RTA_DST; 545 } 546 #define NEXTADDR(w, s) \ 547 if (rtm->rtm_addrs & (w)) { \ 548 (void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);} 549 550 NEXTADDR(RTA_DST, sin_m); 551 NEXTADDR(RTA_GATEWAY, sdl_m); 552 NEXTADDR(RTA_NETMASK, so_mask); 553 554 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 555 doit: 556 l = rtm->rtm_msglen; 557 rtm->rtm_seq = ++seq; 558 rtm->rtm_type = cmd; 559 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 560 if (errno != ESRCH || cmd != RTM_DELETE) { 561 warn("writing to routing socket"); 562 return (-1); 563 } 564 } 565 do { 566 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 567 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 568 if (l < 0) 569 warn("read from routing socket"); 570 return (0); 571 } 572 573 int 574 getinetaddr(host, inap) 575 const char *host; 576 struct in_addr *inap; 577 { 578 struct hostent *hp; 579 580 if (inet_aton(host, inap) == 1) 581 return (0); 582 if ((hp = gethostbyname(host)) == NULL) { 583 warnx("%s: %s\n", host, hstrerror(h_errno)); 584 return (-1); 585 } 586 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 587 return (0); 588 } 589
Indexes created Tue Sep 30 20:09:53 GMT 2025