arp.c revision 1.36
1 /* $NetBSD: arp.c,v 1.36 2003/05/17 00:50:36 itojun 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 1.36 2003/05/17 00:50:36 itojun 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 #include <sys/ioctl.h> 66 67 #include <net/if.h> 68 #include <net/if_dl.h> 69 #include <net/if_ether.h> 70 #include <net/if_types.h> 71 #include <net/route.h> 72 #include <netinet/in.h> 73 #include <netinet/if_inarp.h> 74 #include <arpa/inet.h> 75 76 #include <err.h> 77 #include <errno.h> 78 #include <netdb.h> 79 #include <nlist.h> 80 #include <paths.h> 81 #include <stdio.h> 82 #include <stdlib.h> 83 #include <string.h> 84 #include <unistd.h> 85 #include <ifaddrs.h> 86 87 int delete __P((const char *, const char *)); 88 void dump __P((u_long)); 89 void delete_all __P((void)); 90 void sdl_print __P((const struct sockaddr_dl *)); 91 int getifname __P((u_int16_t, char *)); 92 int atosdl __P((const char *s, struct sockaddr_dl *sdl)); 93 int file __P((char *)); 94 void get __P((const char *)); 95 int getinetaddr __P((const char *, struct in_addr *)); 96 void getsocket __P((void)); 97 int main __P((int, char **)); 98 int rtmsg __P((int)); 99 int set __P((int, char **)); 100 void usage __P((void)); 101 102 static int pid; 103 static int aflag, nflag, vflag; 104 static int s = -1; 105 static struct ifaddrs* ifaddrs = NULL; 106 107 int 108 main(argc, argv) 109 int argc; 110 char **argv; 111 { 112 int ch; 113 int op = 0; 114 115 setprogname(argv[0]); 116 117 pid = getpid(); 118 119 while ((ch = getopt(argc, argv, "andsfv")) != -1) 120 switch((char)ch) { 121 case 'a': 122 aflag = 1; 123 break; 124 case 'd': 125 case 's': 126 case 'f': 127 if (op) 128 usage(); 129 op = ch; 130 break; 131 case 'n': 132 nflag = 1; 133 break; 134 case 'v': 135 vflag = 1; 136 break; 137 default: 138 usage(); 139 } 140 argc -= optind; 141 argv += optind; 142 143 if (!op && aflag) 144 op = 'a'; 145 146 switch((char)op) { 147 case 'a': 148 dump(0); 149 break; 150 case 'd': 151 if (aflag && argc == 0) 152 delete_all(); 153 else { 154 if (aflag || argc < 1 || argc > 2) 155 usage(); 156 (void)delete(argv[0], argv[1]); 157 } 158 break; 159 case 's': 160 if (argc < 2 || argc > 5) 161 usage(); 162 return (set(argc, argv) ? 1 : 0); 163 case 'f': 164 if (argc != 1) 165 usage(); 166 return (file(argv[0])); 167 default: 168 if (argc != 1) 169 usage(); 170 get(argv[0]); 171 break; 172 } 173 return (0); 174 } 175 176 /* 177 * Process a file to set standard arp entries 178 */ 179 int 180 file(name) 181 char *name; 182 { 183 char line[100], arg[5][50], *args[5]; 184 int i, retval; 185 FILE *fp; 186 187 if ((fp = fopen(name, "r")) == NULL) 188 err(1, "cannot open %s", name); 189 args[0] = &arg[0][0]; 190 args[1] = &arg[1][0]; 191 args[2] = &arg[2][0]; 192 args[3] = &arg[3][0]; 193 args[4] = &arg[4][0]; 194 retval = 0; 195 while (fgets(line, 100, fp) != NULL) { 196 i = sscanf(line, "%49s %49s %49s %49s %49s", 197 arg[0], arg[1], arg[2], arg[3], arg[4]); 198 if (i < 2) { 199 warnx("bad line: %s", line); 200 retval = 1; 201 continue; 202 } 203 if (set(i, args)) 204 retval = 1; 205 } 206 fclose(fp); 207 return (retval); 208 } 209 210 void 211 getsocket() 212 { 213 if (s >= 0) 214 return; 215 s = socket(PF_ROUTE, SOCK_RAW, 0); 216 if (s < 0) 217 err(1, "socket"); 218 } 219 220 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 221 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 222 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 223 int expire_time, flags, export_only, doing_proxy, found_entry; 224 struct { 225 struct rt_msghdr m_rtm; 226 char m_space[512]; 227 } m_rtmsg; 228 229 /* 230 * Set an individual arp entry 231 */ 232 int 233 set(argc, argv) 234 int argc; 235 char **argv; 236 { 237 struct sockaddr_inarp *sin; 238 struct sockaddr_dl *sdl; 239 struct rt_msghdr *rtm; 240 char *host = argv[0], *eaddr; 241 int rval; 242 243 sin = &sin_m; 244 rtm = &(m_rtmsg.m_rtm); 245 eaddr = argv[1]; 246 247 getsocket(); 248 argc -= 2; 249 argv += 2; 250 sdl_m = blank_sdl; /* struct copy */ 251 sin_m = blank_sin; /* struct copy */ 252 if (getinetaddr(host, &sin->sin_addr) == -1) 253 return (1); 254 if (atosdl(eaddr, &sdl_m)) 255 warnx("invalid link-level address '%s'", eaddr); 256 doing_proxy = flags = export_only = expire_time = 0; 257 while (argc-- > 0) { 258 if (strncmp(argv[0], "temp", 4) == 0) { 259 struct timeval time; 260 (void)gettimeofday(&time, 0); 261 expire_time = time.tv_sec + 20 * 60; 262 } 263 else if (strncmp(argv[0], "pub", 3) == 0) { 264 flags |= RTF_ANNOUNCE; 265 doing_proxy = SIN_PROXY; 266 } else if (strncmp(argv[0], "trail", 5) == 0) { 267 (void)printf( 268 "%s: Sending trailers is no longer supported\n", 269 host); 270 } 271 argv++; 272 } 273 tryagain: 274 if (rtmsg(RTM_GET) < 0) { 275 warn("%s", host); 276 return (1); 277 } 278 sin = (struct sockaddr_inarp *)(rtm + 1); 279 sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 280 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 281 if (sdl->sdl_family == AF_LINK && 282 (rtm->rtm_flags & RTF_LLINFO) && 283 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 284 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 285 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 286 goto overwrite; 287 } 288 if (doing_proxy == 0) { 289 (void)printf("set: can only proxy for %s\n", host); 290 return (1); 291 } 292 if (sin_m.sin_other & SIN_PROXY) { 293 (void)printf( 294 "set: proxy entry exists for non 802 device\n"); 295 return (1); 296 } 297 sin_m.sin_other = SIN_PROXY; 298 export_only = 1; 299 goto tryagain; 300 } 301 overwrite: 302 if (sdl->sdl_family != AF_LINK) { 303 (void)printf("cannot intuit interface index and type for %s\n", 304 host); 305 return (1); 306 } 307 sdl_m.sdl_type = sdl->sdl_type; 308 sdl_m.sdl_index = sdl->sdl_index; 309 rval = rtmsg(RTM_ADD); 310 if (vflag) 311 (void)printf("%s (%s) added\n", host, eaddr); 312 return (rval); 313 } 314 315 /* 316 * Display an individual arp entry 317 */ 318 void 319 get(host) 320 const char *host; 321 { 322 struct sockaddr_inarp *sin; 323 324 sin = &sin_m; 325 sin_m = blank_sin; /* struct copy */ 326 if (getinetaddr(host, &sin->sin_addr) == -1) 327 exit(1); 328 dump(sin->sin_addr.s_addr); 329 if (found_entry == 0) { 330 (void)printf("%s (%s) -- no entry\n", host, 331 inet_ntoa(sin->sin_addr)); 332 exit(1); 333 } 334 } 335 336 /* 337 * Delete an arp entry 338 */ 339 int 340 delete(host, info) 341 const char *host; 342 const char *info; 343 { 344 struct sockaddr_inarp *sin; 345 struct rt_msghdr *rtm; 346 struct sockaddr_dl *sdl; 347 348 sin = &sin_m; 349 rtm = &m_rtmsg.m_rtm; 350 351 if (info && strncmp(info, "pro", 3) ) 352 export_only = 1; 353 getsocket(); 354 sin_m = blank_sin; /* struct copy */ 355 if (getinetaddr(host, &sin->sin_addr) == -1) 356 return (1); 357 tryagain: 358 if (rtmsg(RTM_GET) < 0) { 359 warn("%s", host); 360 return (1); 361 } 362 sin = (struct sockaddr_inarp *)(rtm + 1); 363 sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 364 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 365 if (sdl->sdl_family == AF_LINK && 366 (rtm->rtm_flags & RTF_LLINFO) && 367 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 368 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 369 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 370 goto delete; 371 } 372 } 373 if (sin_m.sin_other & SIN_PROXY) { 374 warnx("delete: can't locate %s", host); 375 return (1); 376 } else { 377 sin_m.sin_other = SIN_PROXY; 378 goto tryagain; 379 } 380 delete: 381 if (sdl->sdl_family != AF_LINK) { 382 (void)printf("cannot locate %s\n", host); 383 return (1); 384 } 385 if (rtmsg(RTM_DELETE)) 386 return (1); 387 if (vflag) 388 (void)printf("%s (%s) deleted\n", host, 389 inet_ntoa(sin->sin_addr)); 390 return (0); 391 } 392 393 /* 394 * Dump the entire arp table 395 */ 396 void 397 dump(addr) 398 u_long addr; 399 { 400 int mib[6]; 401 size_t needed; 402 char ifname[IFNAMSIZ]; 403 char *host, *lim, *buf, *next; 404 struct rt_msghdr *rtm; 405 struct sockaddr_inarp *sin; 406 struct sockaddr_dl *sdl; 407 struct hostent *hp; 408 409 mib[0] = CTL_NET; 410 mib[1] = PF_ROUTE; 411 mib[2] = 0; 412 mib[3] = AF_INET; 413 mib[4] = NET_RT_FLAGS; 414 mib[5] = RTF_LLINFO; 415 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 416 err(1, "route-sysctl-estimate"); 417 if (needed == 0) 418 return; 419 if ((buf = malloc(needed)) == NULL) 420 err(1, "malloc"); 421 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 422 err(1, "actual retrieval of routing table"); 423 lim = buf + needed; 424 for (next = buf; next < lim; next += rtm->rtm_msglen) { 425 rtm = (struct rt_msghdr *)next; 426 sin = (struct sockaddr_inarp *)(rtm + 1); 427 sdl = (struct sockaddr_dl *) 428 (ROUNDUP(sin->sin_len) + (char *)sin); 429 if (addr) { 430 if (addr != sin->sin_addr.s_addr) 431 continue; 432 found_entry = 1; 433 } 434 if (nflag == 0) 435 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 436 sizeof sin->sin_addr, AF_INET); 437 else 438 hp = NULL; 439 440 host = hp ? hp->h_name : "?"; 441 442 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 443 if (sdl->sdl_alen) 444 sdl_print(sdl); 445 else 446 (void)printf("(incomplete)"); 447 448 if (sdl->sdl_index) { 449 if (getifname(sdl->sdl_index, ifname) == 0) 450 printf(" on %s", ifname); 451 } 452 453 if (rtm->rtm_rmx.rmx_expire == 0) 454 (void)printf(" permanent"); 455 if (sin->sin_other & SIN_PROXY) 456 (void)printf(" published (proxy only)"); 457 if (rtm->rtm_addrs & RTA_NETMASK) { 458 sin = (struct sockaddr_inarp *) 459 (ROUNDUP(sdl->sdl_len) + (char *)sdl); 460 if (sin->sin_addr.s_addr == 0xffffffff) 461 (void)printf(" published"); 462 if (sin->sin_len != 8) 463 (void)printf("(weird)"); 464 } 465 (void)printf("\n"); 466 } 467 } 468 469 /* 470 * Delete the entire arp table 471 */ 472 void 473 delete_all(void) 474 { 475 int mib[6]; 476 size_t needed; 477 char addr[sizeof("000.000.000.000\0")]; 478 char *lim, *buf, *next; 479 struct rt_msghdr *rtm; 480 struct sockaddr_inarp *sin; 481 struct sockaddr_dl *sdl; 482 483 mib[0] = CTL_NET; 484 mib[1] = PF_ROUTE; 485 mib[2] = 0; 486 mib[3] = AF_INET; 487 mib[4] = NET_RT_FLAGS; 488 mib[5] = RTF_LLINFO; 489 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 490 err(1, "route-sysctl-estimate"); 491 if (needed == 0) 492 return; 493 if ((buf = malloc(needed)) == NULL) 494 err(1, "malloc"); 495 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 496 err(1, "actual retrieval of routing table"); 497 lim = buf + needed; 498 for (next = buf; next < lim; next += rtm->rtm_msglen) { 499 rtm = (struct rt_msghdr *)next; 500 sin = (struct sockaddr_inarp *)(rtm + 1); 501 sdl = (struct sockaddr_dl *) 502 (ROUNDUP(sin->sin_len) + (char *)sin); 503 snprintf(addr, sizeof(addr), "%s", inet_ntoa(sin->sin_addr)); 504 delete(addr, NULL); 505 } 506 } 507 508 void 509 sdl_print(sdl) 510 const struct sockaddr_dl *sdl; 511 { 512 char hbuf[NI_MAXHOST]; 513 514 if (getnameinfo((struct sockaddr *)sdl, sdl->sdl_len, 515 hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) 516 printf("<invalid>"); 517 else 518 printf("%s", hbuf); 519 } 520 521 int 522 atosdl(s, sdl) 523 const char *s; 524 struct sockaddr_dl *sdl; 525 { 526 int i; 527 long b; 528 caddr_t endp; 529 caddr_t p; 530 char *t, *r; 531 532 p = LLADDR(sdl); 533 endp = ((caddr_t)sdl) + sdl->sdl_len; 534 i = 0; 535 536 b = strtol(s, &t, 16); 537 if (t == s) 538 return 1; 539 540 *p++ = b; 541 ++i; 542 while ((p < endp) && (*t++ == ':')) { 543 b = strtol(t, &r, 16); 544 if (r == t) 545 break; 546 *p++ = b; 547 ++i; 548 t = r; 549 } 550 sdl->sdl_alen = i; 551 552 return 0; 553 } 554 555 void 556 usage() 557 { 558 const char *progname; 559 560 progname = getprogname(); 561 (void)fprintf(stderr, "usage: %s [-n] hostname\n", progname); 562 (void)fprintf(stderr, "usage: %s [-n] -a\n", progname); 563 (void)fprintf(stderr, "usage: %s -d [-a|hostname]\n", progname); 564 (void)fprintf(stderr, 565 "usage: %s -s hostname ether_addr [temp] [pub]\n", progname); 566 (void)fprintf(stderr, "usage: %s -f filename\n", progname); 567 exit(1); 568 } 569 570 int 571 rtmsg(cmd) 572 int cmd; 573 { 574 static int seq; 575 int rlen; 576 struct rt_msghdr *rtm; 577 char *cp; 578 int l; 579 580 rtm = &m_rtmsg.m_rtm; 581 cp = m_rtmsg.m_space; 582 errno = 0; 583 584 if (cmd == RTM_DELETE) 585 goto doit; 586 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 587 rtm->rtm_flags = flags; 588 rtm->rtm_version = RTM_VERSION; 589 590 switch (cmd) { 591 default: 592 errx(1, "internal wrong cmd"); 593 /*NOTREACHED*/ 594 case RTM_ADD: 595 rtm->rtm_addrs |= RTA_GATEWAY; 596 rtm->rtm_rmx.rmx_expire = expire_time; 597 rtm->rtm_inits = RTV_EXPIRE; 598 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 599 sin_m.sin_other = 0; 600 if (doing_proxy) { 601 if (export_only) 602 sin_m.sin_other = SIN_PROXY; 603 else { 604 rtm->rtm_addrs |= RTA_NETMASK; 605 rtm->rtm_flags &= ~RTF_HOST; 606 } 607 } 608 /* FALLTHROUGH */ 609 case RTM_GET: 610 rtm->rtm_addrs |= RTA_DST; 611 } 612 613 #define NEXTADDR(w, s) \ 614 if (rtm->rtm_addrs & (w)) { \ 615 (void)memcpy(cp, &s, ((struct sockaddr *)&s)->sa_len); \ 616 cp += ROUNDUP(((struct sockaddr *)&s)->sa_len); \ 617 } 618 619 NEXTADDR(RTA_DST, sin_m); 620 NEXTADDR(RTA_GATEWAY, sdl_m); 621 NEXTADDR(RTA_NETMASK, so_mask); 622 623 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 624 doit: 625 l = rtm->rtm_msglen; 626 rtm->rtm_seq = ++seq; 627 rtm->rtm_type = cmd; 628 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 629 if (errno != ESRCH || cmd != RTM_DELETE) { 630 warn("writing to routing socket"); 631 return (-1); 632 } 633 } 634 do { 635 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 636 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 637 if (l < 0) 638 warn("read from routing socket"); 639 return (0); 640 } 641 642 int 643 getinetaddr(host, inap) 644 const char *host; 645 struct in_addr *inap; 646 { 647 struct hostent *hp; 648 649 if (inet_aton(host, inap) == 1) 650 return (0); 651 if ((hp = gethostbyname(host)) == NULL) { 652 warnx("%s: %s", host, hstrerror(h_errno)); 653 return (-1); 654 } 655 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 656 return (0); 657 } 658 659 int 660 getifname(ifindex, ifname) 661 u_int16_t ifindex; 662 char* ifname; 663 { 664 int i; 665 struct ifaddrs *addr; 666 const struct sockaddr_dl *sdl = NULL; 667 668 if (ifaddrs == NULL) { 669 i = getifaddrs(&ifaddrs); 670 if (i != 0) 671 err(1, "getifaddrs"); 672 } 673 674 for (addr = ifaddrs; addr; addr = addr->ifa_next) { 675 if (addr->ifa_addr == NULL || 676 addr->ifa_addr->sa_family != AF_LINK) 677 continue; 678 679 sdl = (const struct sockaddr_dl *) addr->ifa_addr; 680 if (sdl && sdl->sdl_index == ifindex) { 681 (void) strncpy(ifname, addr->ifa_name, IFNAMSIZ); 682 return 0; 683 } 684 } 685 686 return -1; 687 } 688
Indexes created Tue Sep 30 20:09:53 GMT 2025