arp.c revision 1.27
1 /* $NetBSD: arp.c,v 1.27 2001/01/05 19:34:13 christos 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 #include <sys/cdefs.h> 40 #ifndef lint 41 __COPYRIGHT("@(#) 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 #if 0 47 static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; 48 #else 49 __RCSID("$NetBSD: arp.c,v 1.27 2001/01/05 19:34:13 christos Exp $"); 50 #endif 51 #endif /* not lint */ 52 53 /* 54 * arp - display, set, and delete arp table entries 55 */ 56 57 /* Roundup the same way rt_xaddrs does */ 58 #define ROUNDUP(a) \ 59 ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) 60 61 #include <sys/param.h> 62 #include <sys/file.h> 63 #include <sys/socket.h> 64 #include <sys/sysctl.h> 65 66 #include <net/if.h> 67 #include <net/if_dl.h> 68 #include <net/if_ether.h> 69 #include <net/if_types.h> 70 #include <net/route.h> 71 #include <netinet/in.h> 72 #include <netinet/if_inarp.h> 73 #include <arpa/inet.h> 74 75 #include <err.h> 76 #include <errno.h> 77 #include <netdb.h> 78 #include <nlist.h> 79 #include <paths.h> 80 #include <stdio.h> 81 #include <stdlib.h> 82 #include <string.h> 83 #include <unistd.h> 84 85 int delete __P((const char *, const char *)); 86 void dump __P((u_long)); 87 void sdl_print __P((const struct sockaddr_dl *)); 88 int atosdl __P((const char *s, struct sockaddr_dl *sdl)); 89 int file __P((char *)); 90 void get __P((const char *)); 91 int getinetaddr __P((const char *, struct in_addr *)); 92 void getsocket __P((void)); 93 int main __P((int, char **)); 94 int rtmsg __P((int)); 95 int set __P((int, char **)); 96 void usage __P((void)); 97 98 static int pid; 99 static int nflag, vflag; 100 static int s = -1; 101 102 extern char *__progname; 103 104 int 105 main(argc, argv) 106 int argc; 107 char **argv; 108 { 109 int ch; 110 int op = 0; 111 112 pid = getpid(); 113 114 while ((ch = getopt(argc, argv, "andsfv")) != -1) 115 switch((char)ch) { 116 case 'a': 117 case 'd': 118 case 's': 119 case 'f': 120 if (op) 121 usage(); 122 op = ch; 123 break; 124 case 'n': 125 nflag = 1; 126 break; 127 case 'v': 128 vflag = 1; 129 break; 130 default: 131 usage(); 132 } 133 argc -= optind; 134 argv += optind; 135 136 switch((char)op) { 137 case 'a': 138 dump(0); 139 break; 140 case 'd': 141 if (argc < 1 || argc > 2) 142 usage(); 143 (void)delete(argv[0], argv[1]); 144 break; 145 case 's': 146 if (argc < 2 || argc > 5) 147 usage(); 148 return (set(argc, argv) ? 1 : 0); 149 case 'f': 150 if (argc != 1) 151 usage(); 152 return (file(argv[0])); 153 default: 154 if (argc != 1) 155 usage(); 156 get(argv[0]); 157 break; 158 } 159 return (0); 160 } 161 162 /* 163 * Process a file to set standard arp entries 164 */ 165 int 166 file(name) 167 char *name; 168 { 169 char line[100], arg[5][50], *args[5]; 170 int i, retval; 171 FILE *fp; 172 173 if ((fp = fopen(name, "r")) == NULL) 174 err(1, "cannot open %s", name); 175 args[0] = &arg[0][0]; 176 args[1] = &arg[1][0]; 177 args[2] = &arg[2][0]; 178 args[3] = &arg[3][0]; 179 args[4] = &arg[4][0]; 180 retval = 0; 181 while (fgets(line, 100, fp) != NULL) { 182 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 183 arg[3], arg[4]); 184 if (i < 2) { 185 warnx("bad line: %s", line); 186 retval = 1; 187 continue; 188 } 189 if (set(i, args)) 190 retval = 1; 191 } 192 fclose(fp); 193 return (retval); 194 } 195 196 void 197 getsocket() 198 { 199 if (s >= 0) 200 return; 201 s = socket(PF_ROUTE, SOCK_RAW, 0); 202 if (s < 0) 203 err(1, "socket"); 204 } 205 206 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 207 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 208 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 209 int expire_time, flags, export_only, doing_proxy, found_entry; 210 struct { 211 struct rt_msghdr m_rtm; 212 char m_space[512]; 213 } m_rtmsg; 214 215 /* 216 * Set an individual arp entry 217 */ 218 int 219 set(argc, argv) 220 int argc; 221 char **argv; 222 { 223 struct sockaddr_inarp *sin; 224 struct sockaddr_dl *sdl; 225 struct rt_msghdr *rtm; 226 char *host = argv[0], *eaddr; 227 int rval; 228 229 sin = &sin_m; 230 rtm = &(m_rtmsg.m_rtm); 231 eaddr = argv[1]; 232 233 getsocket(); 234 argc -= 2; 235 argv += 2; 236 sdl_m = blank_sdl; /* struct copy */ 237 sin_m = blank_sin; /* struct copy */ 238 if (getinetaddr(host, &sin->sin_addr) == -1) 239 return (1); 240 if (atosdl(eaddr, &sdl_m)) 241 warnx("invalid link-level address '%s'", eaddr); 242 doing_proxy = flags = export_only = expire_time = 0; 243 while (argc-- > 0) { 244 if (strncmp(argv[0], "temp", 4) == 0) { 245 struct timeval time; 246 (void)gettimeofday(&time, 0); 247 expire_time = time.tv_sec + 20 * 60; 248 } 249 else if (strncmp(argv[0], "pub", 3) == 0) { 250 flags |= RTF_ANNOUNCE; 251 doing_proxy = SIN_PROXY; 252 } else if (strncmp(argv[0], "trail", 5) == 0) { 253 (void)printf( 254 "%s: Sending trailers is no longer supported\n", 255 host); 256 } 257 argv++; 258 } 259 tryagain: 260 if (rtmsg(RTM_GET) < 0) { 261 warn("%s", host); 262 return (1); 263 } 264 sin = (struct sockaddr_inarp *)(rtm + 1); 265 sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 266 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 267 if (sdl->sdl_family == AF_LINK && 268 (rtm->rtm_flags & RTF_LLINFO) && 269 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 270 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 271 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 272 goto overwrite; 273 } 274 if (doing_proxy == 0) { 275 (void)printf("set: can only proxy for %s\n", host); 276 return (1); 277 } 278 if (sin_m.sin_other & SIN_PROXY) { 279 (void)printf( 280 "set: proxy entry exists for non 802 device\n"); 281 return (1); 282 } 283 sin_m.sin_other = SIN_PROXY; 284 export_only = 1; 285 goto tryagain; 286 } 287 overwrite: 288 if (sdl->sdl_family != AF_LINK) { 289 (void)printf("cannot intuit interface index and type for %s\n", 290 host); 291 return (1); 292 } 293 sdl_m.sdl_type = sdl->sdl_type; 294 sdl_m.sdl_index = sdl->sdl_index; 295 rval = rtmsg(RTM_ADD); 296 if (vflag) 297 (void)printf("%s (%s) added\n", host, eaddr); 298 return (rval); 299 } 300 301 /* 302 * Display an individual arp entry 303 */ 304 void 305 get(host) 306 const char *host; 307 { 308 struct sockaddr_inarp *sin; 309 310 sin = &sin_m; 311 sin_m = blank_sin; /* struct copy */ 312 if (getinetaddr(host, &sin->sin_addr) == -1) 313 exit(1); 314 dump(sin->sin_addr.s_addr); 315 if (found_entry == 0) { 316 (void)printf("%s (%s) -- no entry\n", host, 317 inet_ntoa(sin->sin_addr)); 318 exit(1); 319 } 320 } 321 322 /* 323 * Delete an arp entry 324 */ 325 int 326 delete(host, info) 327 const char *host; 328 const char *info; 329 { 330 struct sockaddr_inarp *sin; 331 struct rt_msghdr *rtm; 332 struct sockaddr_dl *sdl; 333 334 sin = &sin_m; 335 rtm = &m_rtmsg.m_rtm; 336 337 if (info && strncmp(info, "pro", 3) ) 338 export_only = 1; 339 getsocket(); 340 sin_m = blank_sin; /* struct copy */ 341 if (getinetaddr(host, &sin->sin_addr) == -1) 342 return (1); 343 tryagain: 344 if (rtmsg(RTM_GET) < 0) { 345 warn("%s", host); 346 return (1); 347 } 348 sin = (struct sockaddr_inarp *)(rtm + 1); 349 sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 350 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 351 if (sdl->sdl_family == AF_LINK && 352 (rtm->rtm_flags & RTF_LLINFO) && 353 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 354 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 355 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 356 goto delete; 357 } 358 } 359 if (sin_m.sin_other & SIN_PROXY) { 360 warnx("delete: can't locate %s", host); 361 return (1); 362 } else { 363 sin_m.sin_other = SIN_PROXY; 364 goto tryagain; 365 } 366 delete: 367 if (sdl->sdl_family != AF_LINK) { 368 (void)printf("cannot locate %s\n", host); 369 return (1); 370 } 371 if (rtmsg(RTM_DELETE)) 372 return (1); 373 if (vflag) 374 (void)printf("%s (%s) deleted\n", host, 375 inet_ntoa(sin->sin_addr)); 376 return (0); 377 } 378 379 /* 380 * Dump the entire arp table 381 */ 382 void 383 dump(addr) 384 u_long addr; 385 { 386 int mib[6]; 387 size_t needed; 388 char *host, *lim, *buf, *next; 389 struct rt_msghdr *rtm; 390 struct sockaddr_inarp *sin; 391 struct sockaddr_dl *sdl; 392 struct hostent *hp; 393 394 mib[0] = CTL_NET; 395 mib[1] = PF_ROUTE; 396 mib[2] = 0; 397 mib[3] = AF_INET; 398 mib[4] = NET_RT_FLAGS; 399 mib[5] = RTF_LLINFO; 400 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 401 err(1, "route-sysctl-estimate"); 402 if (needed == 0) 403 return; 404 if ((buf = malloc(needed)) == NULL) 405 err(1, "malloc"); 406 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 407 err(1, "actual retrieval of routing table"); 408 lim = buf + needed; 409 for (next = buf; next < lim; next += rtm->rtm_msglen) { 410 rtm = (struct rt_msghdr *)next; 411 sin = (struct sockaddr_inarp *)(rtm + 1); 412 sdl = (struct sockaddr_dl *) 413 (ROUNDUP(sin->sin_len) + (char *)sin); 414 if (addr) { 415 if (addr != sin->sin_addr.s_addr) 416 continue; 417 found_entry = 1; 418 } 419 if (nflag == 0) 420 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 421 sizeof sin->sin_addr, AF_INET); 422 else 423 hp = NULL; 424 425 host = hp ? hp->h_name : "?"; 426 427 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 428 if (sdl->sdl_alen) 429 sdl_print(sdl); 430 else 431 (void)printf("(incomplete)"); 432 if (rtm->rtm_rmx.rmx_expire == 0) 433 (void)printf(" permanent"); 434 if (sin->sin_other & SIN_PROXY) 435 (void)printf(" published (proxy only)"); 436 if (rtm->rtm_addrs & RTA_NETMASK) { 437 sin = (struct sockaddr_inarp *) 438 (ROUNDUP(sdl->sdl_len) + (char *)sdl); 439 if (sin->sin_addr.s_addr == 0xffffffff) 440 (void)printf(" published"); 441 if (sin->sin_len != 8) 442 (void)printf("(weird)"); 443 } 444 (void)printf("\n"); 445 } 446 } 447 448 void 449 sdl_print(sdl) 450 const struct sockaddr_dl *sdl; 451 { 452 int i; 453 u_int8_t *p; 454 455 i = sdl->sdl_alen; 456 p = LLADDR(sdl); 457 458 (void)printf("%02x", *p); 459 while (--i > 0) { 460 putchar(':'); 461 (void)printf("%02x", *++p); 462 } 463 } 464 465 int 466 atosdl(s, sdl) 467 const char *s; 468 struct sockaddr_dl *sdl; 469 { 470 int i; 471 long b; 472 caddr_t endp; 473 caddr_t p; 474 char *t, *r; 475 476 p = LLADDR(sdl); 477 endp = ((caddr_t)sdl) + sdl->sdl_len; 478 i = 0; 479 480 b = strtol(s, &t, 16); 481 if (t == s) 482 return 1; 483 484 *p++ = b; 485 ++i; 486 while ((p < endp) && (*t++ == ':')) { 487 b = strtol(t, &r, 16); 488 if (r == t) 489 break; 490 *p++ = b; 491 ++i; 492 t = r; 493 } 494 sdl->sdl_alen = i; 495 496 return 0; 497 } 498 499 void 500 usage() 501 { 502 503 (void)fprintf(stderr, "usage: %s [-n] hostname\n", __progname); 504 (void)fprintf(stderr, "usage: %s [-n] -a\n", __progname); 505 (void)fprintf(stderr, "usage: %s -d hostname\n", __progname); 506 (void)fprintf(stderr, 507 "usage: %s -s hostname ether_addr [temp] [pub]\n", __progname); 508 (void)fprintf(stderr, "usage: %s -f filename\n", __progname); 509 exit(1); 510 } 511 512 int 513 rtmsg(cmd) 514 int cmd; 515 { 516 static int seq; 517 int rlen; 518 struct rt_msghdr *rtm; 519 char *cp; 520 int l; 521 522 rtm = &m_rtmsg.m_rtm; 523 cp = m_rtmsg.m_space; 524 errno = 0; 525 526 if (cmd == RTM_DELETE) 527 goto doit; 528 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 529 rtm->rtm_flags = flags; 530 rtm->rtm_version = RTM_VERSION; 531 532 switch (cmd) { 533 default: 534 errx(1, "internal wrong cmd"); 535 /*NOTREACHED*/ 536 case RTM_ADD: 537 rtm->rtm_addrs |= RTA_GATEWAY; 538 rtm->rtm_rmx.rmx_expire = expire_time; 539 rtm->rtm_inits = RTV_EXPIRE; 540 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 541 sin_m.sin_other = 0; 542 if (doing_proxy) { 543 if (export_only) 544 sin_m.sin_other = SIN_PROXY; 545 else { 546 rtm->rtm_addrs |= RTA_NETMASK; 547 rtm->rtm_flags &= ~RTF_HOST; 548 } 549 } 550 /* FALLTHROUGH */ 551 case RTM_GET: 552 rtm->rtm_addrs |= RTA_DST; 553 } 554 555 #define NEXTADDR(w, s) \ 556 if (rtm->rtm_addrs & (w)) { \ 557 (void)memcpy(cp, &s, ((struct sockaddr *)&s)->sa_len); \ 558 cp += ROUNDUP(((struct sockaddr *)&s)->sa_len); \ 559 } 560 561 NEXTADDR(RTA_DST, sin_m); 562 NEXTADDR(RTA_GATEWAY, sdl_m); 563 NEXTADDR(RTA_NETMASK, so_mask); 564 565 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 566 doit: 567 l = rtm->rtm_msglen; 568 rtm->rtm_seq = ++seq; 569 rtm->rtm_type = cmd; 570 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 571 if (errno != ESRCH || cmd != RTM_DELETE) { 572 warn("writing to routing socket"); 573 return (-1); 574 } 575 } 576 do { 577 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 578 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 579 if (l < 0) 580 warn("read from routing socket"); 581 return (0); 582 } 583 584 int 585 getinetaddr(host, inap) 586 const char *host; 587 struct in_addr *inap; 588 { 589 struct hostent *hp; 590 591 if (inet_aton(host, inap) == 1) 592 return (0); 593 if ((hp = gethostbyname(host)) == NULL) { 594 warnx("%s: %s\n", host, hstrerror(h_errno)); 595 return (-1); 596 } 597 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 598 return (0); 599 } 600
Indexes created Tue Sep 30 20:09:53 GMT 2025