arp.c revision 1.15.2.2
1 /* $NetBSD: arp.c,v 1.15.2.2 1997/02/19 18:19:17 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[] = "from: @(#)arp.c 8.2 (Berkeley) 1/2/94";*/ 47 static char *rcsid = "$NetBSD: arp.c,v 1.15.2.2 1997/02/19 18:19:17 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_ether.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 95 main(argc, argv) 96 int argc; 97 char **argv; 98 { 99 int ch; 100 int op = 0; 101 102 pid = getpid(); 103 104 while ((ch = getopt(argc, argv, "andsf")) != -1) 105 switch((char)ch) { 106 case 'a': 107 case 'd': 108 case 's': 109 case 'f': 110 if (op) 111 usage(); 112 op = ch; 113 break; 114 case 'n': 115 nflag = 1; 116 break; 117 default: 118 usage(); 119 } 120 argc -= optind; 121 argv += optind; 122 123 switch((char)op) { 124 case 'a': 125 dump(0); 126 break; 127 case 'd': 128 if (argc < 1 || argc > 2) 129 usage(); 130 (void)delete(argv[0], argv[1]); 131 break; 132 case 's': 133 if (argc < 2 || argc > 5) 134 usage(); 135 return (set(argc, argv) ? 1 : 0); 136 case 'f': 137 if (argc != 1) 138 usage(); 139 return (file(argv[0])); 140 default: 141 if (argc != 1) 142 usage(); 143 get(argv[0]); 144 break; 145 } 146 return (0); 147 } 148 149 /* 150 * Process a file to set standard arp entries 151 */ 152 int 153 file(name) 154 char *name; 155 { 156 char line[100], arg[5][50], *args[5]; 157 int i, retval; 158 FILE *fp; 159 160 if ((fp = fopen(name, "r")) == NULL) 161 err(1, "cannot open %s", name); 162 args[0] = &arg[0][0]; 163 args[1] = &arg[1][0]; 164 args[2] = &arg[2][0]; 165 args[3] = &arg[3][0]; 166 args[4] = &arg[4][0]; 167 retval = 0; 168 while (fgets(line, 100, fp) != NULL) { 169 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 170 arg[3], arg[4]); 171 if (i < 2) { 172 warnx("bad line: %s", line); 173 retval = 1; 174 continue; 175 } 176 if (set(i, args)) 177 retval = 1; 178 } 179 fclose(fp); 180 return (retval); 181 } 182 183 void 184 getsocket() 185 { 186 if (s >= 0) 187 return; 188 s = socket(PF_ROUTE, SOCK_RAW, 0); 189 if (s < 0) 190 err(1, "socket"); 191 } 192 193 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 194 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 195 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 196 int expire_time, flags, export_only, doing_proxy, found_entry; 197 struct { 198 struct rt_msghdr m_rtm; 199 char m_space[512]; 200 } m_rtmsg; 201 202 /* 203 * Set an individual arp entry 204 */ 205 int 206 set(argc, argv) 207 int argc; 208 char **argv; 209 { 210 register struct sockaddr_inarp *sin; 211 register struct sockaddr_dl *sdl; 212 register struct rt_msghdr *rtm; 213 struct ether_addr *ea; 214 char *host = argv[0], *eaddr; 215 216 sin = &sin_m; 217 rtm = &(m_rtmsg.m_rtm); 218 eaddr = argv[1]; 219 220 getsocket(); 221 argc -= 2; 222 argv += 2; 223 sdl_m = blank_sdl; /* struct copy */ 224 sin_m = blank_sin; /* struct copy */ 225 if (getinetaddr(host, &sin->sin_addr) == -1) 226 return (1); 227 if (atosdl(eaddr, &sdl_m)) 228 warnx("invalid link-level address '%s'", eaddr); 229 doing_proxy = flags = export_only = expire_time = 0; 230 while (argc-- > 0) { 231 if (strncmp(argv[0], "temp", 4) == 0) { 232 struct timeval time; 233 (void)gettimeofday(&time, 0); 234 expire_time = time.tv_sec + 20 * 60; 235 } 236 else if (strncmp(argv[0], "pub", 3) == 0) { 237 flags |= RTF_ANNOUNCE; 238 doing_proxy = SIN_PROXY; 239 } else if (strncmp(argv[0], "trail", 5) == 0) { 240 (void)printf( 241 "%s: Sending trailers is no longer supported\n", 242 host); 243 } 244 argv++; 245 } 246 tryagain: 247 if (rtmsg(RTM_GET) < 0) { 248 warn("%s", host); 249 return (1); 250 } 251 sin = (struct sockaddr_inarp *)(rtm + 1); 252 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 253 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 254 if (sdl->sdl_family == AF_LINK && 255 (rtm->rtm_flags & RTF_LLINFO) && 256 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 257 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 258 case IFT_ISO88024: case IFT_ISO88025: 259 goto overwrite; 260 } 261 if (doing_proxy == 0) { 262 (void)printf("set: can only proxy for %s\n", host); 263 return (1); 264 } 265 if (sin_m.sin_other & SIN_PROXY) { 266 (void)printf( 267 "set: proxy entry exists for non 802 device\n"); 268 return (1); 269 } 270 sin_m.sin_other = SIN_PROXY; 271 export_only = 1; 272 goto tryagain; 273 } 274 overwrite: 275 if (sdl->sdl_family != AF_LINK) { 276 (void)printf("cannot intuit interface index and type for %s\n", 277 host); 278 return (1); 279 } 280 sdl_m.sdl_type = sdl->sdl_type; 281 sdl_m.sdl_index = sdl->sdl_index; 282 return (rtmsg(RTM_ADD)); 283 } 284 285 /* 286 * Display an individual arp entry 287 */ 288 void 289 get(host) 290 const char *host; 291 { 292 struct sockaddr_inarp *sin; 293 294 sin = &sin_m; 295 sin_m = blank_sin; /* struct copy */ 296 if (getinetaddr(host, &sin->sin_addr) == -1) 297 exit(1); 298 dump(sin->sin_addr.s_addr); 299 if (found_entry == 0) { 300 (void)printf("%s (%s) -- no entry\n", host, 301 inet_ntoa(sin->sin_addr)); 302 exit(1); 303 } 304 } 305 306 /* 307 * Delete an arp entry 308 */ 309 int 310 delete(host, info) 311 const char *host; 312 const char *info; 313 { 314 register struct sockaddr_inarp *sin; 315 register struct rt_msghdr *rtm; 316 struct sockaddr_dl *sdl; 317 318 sin = &sin_m; 319 rtm = &m_rtmsg.m_rtm; 320 321 if (info && strncmp(info, "pro", 3) ) 322 export_only = 1; 323 getsocket(); 324 sin_m = blank_sin; /* struct copy */ 325 if (getinetaddr(host, &sin->sin_addr) == -1) 326 return (1); 327 tryagain: 328 if (rtmsg(RTM_GET) < 0) { 329 warn("%s", host); 330 return (1); 331 } 332 sin = (struct sockaddr_inarp *)(rtm + 1); 333 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 334 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 335 if (sdl->sdl_family == AF_LINK && 336 (rtm->rtm_flags & RTF_LLINFO) && 337 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 338 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 339 case IFT_ISO88024: case IFT_ISO88025: 340 goto delete; 341 } 342 } 343 if (sin_m.sin_other & SIN_PROXY) { 344 warnx("delete: can't locate %s", host); 345 return (1); 346 } else { 347 sin_m.sin_other = SIN_PROXY; 348 goto tryagain; 349 } 350 delete: 351 if (sdl->sdl_family != AF_LINK) { 352 (void)printf("cannot locate %s\n", host); 353 return (1); 354 } 355 if (rtmsg(RTM_DELETE)) 356 return (1); 357 (void)printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 358 return (0); 359 } 360 361 /* 362 * Dump the entire arp table 363 */ 364 void 365 dump(addr) 366 u_long addr; 367 { 368 int mib[6]; 369 size_t needed; 370 char *host, *lim, *buf, *next; 371 struct rt_msghdr *rtm; 372 struct sockaddr_inarp *sin; 373 struct sockaddr_dl *sdl; 374 extern int h_errno; 375 struct hostent *hp; 376 377 mib[0] = CTL_NET; 378 mib[1] = PF_ROUTE; 379 mib[2] = 0; 380 mib[3] = AF_INET; 381 mib[4] = NET_RT_FLAGS; 382 mib[5] = RTF_LLINFO; 383 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 384 err(1, "route-sysctl-estimate"); 385 if ((buf = malloc(needed)) == NULL) 386 err(1, "malloc"); 387 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 388 err(1, "actual retrieval of routing table"); 389 lim = buf + needed; 390 for (next = buf; next < lim; next += rtm->rtm_msglen) { 391 rtm = (struct rt_msghdr *)next; 392 sin = (struct sockaddr_inarp *)(rtm + 1); 393 sdl = (struct sockaddr_dl *)(sin + 1); 394 if (addr) { 395 if (addr != sin->sin_addr.s_addr) 396 continue; 397 found_entry = 1; 398 } 399 if (nflag == 0) 400 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 401 sizeof sin->sin_addr, AF_INET); 402 else 403 hp = 0; 404 if (hp) 405 host = hp->h_name; 406 else { 407 host = "?"; 408 if (h_errno == TRY_AGAIN) 409 nflag = 1; 410 } 411 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 412 if (sdl->sdl_alen) 413 sdl_print(sdl); 414 else 415 (void)printf("(incomplete)"); 416 if (rtm->rtm_rmx.rmx_expire == 0) 417 (void)printf(" permanent"); 418 if (sin->sin_other & SIN_PROXY) 419 (void)printf(" published (proxy only)"); 420 if (rtm->rtm_addrs & RTA_NETMASK) { 421 sin = (struct sockaddr_inarp *) 422 (sdl->sdl_len + (char *)sdl); 423 if (sin->sin_addr.s_addr == 0xffffffff) 424 (void)printf(" published"); 425 if (sin->sin_len != 8) 426 (void)printf("(wierd)"); 427 } 428 (void)printf("\n"); 429 } 430 } 431 432 void 433 sdl_print(sdl) 434 const struct sockaddr_dl *sdl; 435 { 436 int i; 437 u_int8_t *p; 438 439 i = sdl->sdl_alen; 440 p = LLADDR(sdl); 441 442 (void)printf("%x", *p); 443 while (--i > 0) 444 (void)printf(":%x", *++p); 445 } 446 447 int 448 atosdl(s, sdl) 449 const char *s; 450 struct sockaddr_dl *sdl; 451 { 452 int i; 453 long b; 454 caddr_t endp; 455 caddr_t p; 456 char *t, *r; 457 458 p = LLADDR(sdl); 459 endp = ((caddr_t)sdl) + sdl->sdl_len; 460 i = 0; 461 462 b = strtol(s, &t, 16); 463 if (t == s) 464 return 1; 465 466 *p++ = b; 467 ++i; 468 while ((p < endp) && (*t++ == ':')) { 469 b = strtol(t, &r, 16); 470 if (r == t) 471 break; 472 *p++ = b; 473 ++i; 474 t = r; 475 } 476 sdl->sdl_alen = i; 477 478 return 0; 479 } 480 481 void 482 usage() 483 { 484 (void)fprintf(stderr, "usage: arp [-n] hostname\n"); 485 (void)fprintf(stderr, "usage: arp [-n] -a\n"); 486 (void)fprintf(stderr, "usage: arp -d hostname\n"); 487 (void)fprintf(stderr, 488 "usage: arp -s hostname ether_addr [temp] [pub]\n"); 489 (void)fprintf(stderr, "usage: arp -f filename\n"); 490 exit(1); 491 } 492 493 int 494 rtmsg(cmd) 495 int cmd; 496 { 497 static int seq; 498 int rlen; 499 register struct rt_msghdr *rtm; 500 register char *cp; 501 register int l; 502 503 rtm = &m_rtmsg.m_rtm; 504 cp = m_rtmsg.m_space; 505 errno = 0; 506 507 if (cmd == RTM_DELETE) 508 goto doit; 509 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 510 rtm->rtm_flags = flags; 511 rtm->rtm_version = RTM_VERSION; 512 513 switch (cmd) { 514 default: 515 errx(1, "internal wrong cmd"); 516 /*NOTREACHED*/ 517 case RTM_ADD: 518 rtm->rtm_addrs |= RTA_GATEWAY; 519 rtm->rtm_rmx.rmx_expire = expire_time; 520 rtm->rtm_inits = RTV_EXPIRE; 521 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 522 sin_m.sin_other = 0; 523 if (doing_proxy) { 524 if (export_only) 525 sin_m.sin_other = SIN_PROXY; 526 else { 527 rtm->rtm_addrs |= RTA_NETMASK; 528 rtm->rtm_flags &= ~RTF_HOST; 529 } 530 } 531 /* FALLTHROUGH */ 532 case RTM_GET: 533 rtm->rtm_addrs |= RTA_DST; 534 } 535 #define NEXTADDR(w, s) \ 536 if (rtm->rtm_addrs & (w)) { \ 537 (void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);} 538 539 NEXTADDR(RTA_DST, sin_m); 540 NEXTADDR(RTA_GATEWAY, sdl_m); 541 NEXTADDR(RTA_NETMASK, so_mask); 542 543 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 544 doit: 545 l = rtm->rtm_msglen; 546 rtm->rtm_seq = ++seq; 547 rtm->rtm_type = cmd; 548 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 549 if (errno != ESRCH || cmd != RTM_DELETE) { 550 warn("writing to routing socket"); 551 return (-1); 552 } 553 } 554 do { 555 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 556 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 557 if (l < 0) 558 warn("read from routing socket"); 559 return (0); 560 } 561 562 int 563 getinetaddr(host, inap) 564 const char *host; 565 struct in_addr *inap; 566 { 567 struct hostent *hp; 568 569 if (inet_aton(host, inap) == 1) 570 return (0); 571 if ((hp = gethostbyname(host)) == NULL) { 572 warnx("%s: %s\n", host, hstrerror(h_errno)); 573 return (-1); 574 } 575 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 576 return (0); 577 } 578
Indexes created Tue Sep 30 20:09:53 GMT 2025