arp.c revision 1.34
1 /* $NetBSD: arp.c,v 1.34 2002/03/02 03:45:07 tv 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 1.34 2002/03/02 03:45:07 tv 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 86 int delete __P((const char *, const char *)); 87 void dump __P((u_long)); 88 void delete_all __P((void)); 89 void sdl_print __P((const struct sockaddr_dl *)); 90 int getifname __P((u_int16_t, char *)); 91 int atosdl __P((const char *s, struct sockaddr_dl *sdl)); 92 int file __P((char *)); 93 void get __P((const char *)); 94 int getinetaddr __P((const char *, struct in_addr *)); 95 void getsocket __P((void)); 96 int main __P((int, char **)); 97 int rtmsg __P((int)); 98 int set __P((int, char **)); 99 void usage __P((void)); 100 101 static int pid; 102 static int aflag, nflag, vflag; 103 static int s = -1; 104 static int is = -1; 105 106 static struct ifconf ifc; 107 static char ifconfbuf[8192]; 108 109 int 110 main(argc, argv) 111 int argc; 112 char **argv; 113 { 114 int ch; 115 int op = 0; 116 117 setprogname(argv[0]); 118 119 pid = getpid(); 120 121 while ((ch = getopt(argc, argv, "andsfv")) != -1) 122 switch((char)ch) { 123 case 'a': 124 aflag = 1; 125 break; 126 case 'd': 127 case 's': 128 case 'f': 129 if (op) 130 usage(); 131 op = ch; 132 break; 133 case 'n': 134 nflag = 1; 135 break; 136 case 'v': 137 vflag = 1; 138 break; 139 default: 140 usage(); 141 } 142 argc -= optind; 143 argv += optind; 144 145 if (!op && aflag) 146 op = 'a'; 147 148 switch((char)op) { 149 case 'a': 150 dump(0); 151 break; 152 case 'd': 153 if (aflag && argc == 0) 154 delete_all(); 155 else { 156 if (aflag || argc < 1 || argc > 2) 157 usage(); 158 (void)delete(argv[0], argv[1]); 159 } 160 break; 161 case 's': 162 if (argc < 2 || argc > 5) 163 usage(); 164 return (set(argc, argv) ? 1 : 0); 165 case 'f': 166 if (argc != 1) 167 usage(); 168 return (file(argv[0])); 169 default: 170 if (argc != 1) 171 usage(); 172 get(argv[0]); 173 break; 174 } 175 return (0); 176 } 177 178 /* 179 * Process a file to set standard arp entries 180 */ 181 int 182 file(name) 183 char *name; 184 { 185 char line[100], arg[5][50], *args[5]; 186 int i, retval; 187 FILE *fp; 188 189 if ((fp = fopen(name, "r")) == NULL) 190 err(1, "cannot open %s", name); 191 args[0] = &arg[0][0]; 192 args[1] = &arg[1][0]; 193 args[2] = &arg[2][0]; 194 args[3] = &arg[3][0]; 195 args[4] = &arg[4][0]; 196 retval = 0; 197 while (fgets(line, 100, fp) != NULL) { 198 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 199 arg[3], arg[4]); 200 if (i < 2) { 201 warnx("bad line: %s", line); 202 retval = 1; 203 continue; 204 } 205 if (set(i, args)) 206 retval = 1; 207 } 208 fclose(fp); 209 return (retval); 210 } 211 212 void 213 getsocket() 214 { 215 if (s >= 0) 216 return; 217 s = socket(PF_ROUTE, SOCK_RAW, 0); 218 if (s < 0) 219 err(1, "socket"); 220 } 221 222 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 223 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 224 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 225 int expire_time, flags, export_only, doing_proxy, found_entry; 226 struct { 227 struct rt_msghdr m_rtm; 228 char m_space[512]; 229 } m_rtmsg; 230 231 /* 232 * Set an individual arp entry 233 */ 234 int 235 set(argc, argv) 236 int argc; 237 char **argv; 238 { 239 struct sockaddr_inarp *sin; 240 struct sockaddr_dl *sdl; 241 struct rt_msghdr *rtm; 242 char *host = argv[0], *eaddr; 243 int rval; 244 245 sin = &sin_m; 246 rtm = &(m_rtmsg.m_rtm); 247 eaddr = argv[1]; 248 249 getsocket(); 250 argc -= 2; 251 argv += 2; 252 sdl_m = blank_sdl; /* struct copy */ 253 sin_m = blank_sin; /* struct copy */ 254 if (getinetaddr(host, &sin->sin_addr) == -1) 255 return (1); 256 if (atosdl(eaddr, &sdl_m)) 257 warnx("invalid link-level address '%s'", eaddr); 258 doing_proxy = flags = export_only = expire_time = 0; 259 while (argc-- > 0) { 260 if (strncmp(argv[0], "temp", 4) == 0) { 261 struct timeval time; 262 (void)gettimeofday(&time, 0); 263 expire_time = time.tv_sec + 20 * 60; 264 } 265 else if (strncmp(argv[0], "pub", 3) == 0) { 266 flags |= RTF_ANNOUNCE; 267 doing_proxy = SIN_PROXY; 268 } else if (strncmp(argv[0], "trail", 5) == 0) { 269 (void)printf( 270 "%s: Sending trailers is no longer supported\n", 271 host); 272 } 273 argv++; 274 } 275 tryagain: 276 if (rtmsg(RTM_GET) < 0) { 277 warn("%s", host); 278 return (1); 279 } 280 sin = (struct sockaddr_inarp *)(rtm + 1); 281 sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 282 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 283 if (sdl->sdl_family == AF_LINK && 284 (rtm->rtm_flags & RTF_LLINFO) && 285 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 286 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 287 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 288 goto overwrite; 289 } 290 if (doing_proxy == 0) { 291 (void)printf("set: can only proxy for %s\n", host); 292 return (1); 293 } 294 if (sin_m.sin_other & SIN_PROXY) { 295 (void)printf( 296 "set: proxy entry exists for non 802 device\n"); 297 return (1); 298 } 299 sin_m.sin_other = SIN_PROXY; 300 export_only = 1; 301 goto tryagain; 302 } 303 overwrite: 304 if (sdl->sdl_family != AF_LINK) { 305 (void)printf("cannot intuit interface index and type for %s\n", 306 host); 307 return (1); 308 } 309 sdl_m.sdl_type = sdl->sdl_type; 310 sdl_m.sdl_index = sdl->sdl_index; 311 rval = rtmsg(RTM_ADD); 312 if (vflag) 313 (void)printf("%s (%s) added\n", host, eaddr); 314 return (rval); 315 } 316 317 /* 318 * Display an individual arp entry 319 */ 320 void 321 get(host) 322 const char *host; 323 { 324 struct sockaddr_inarp *sin; 325 326 sin = &sin_m; 327 sin_m = blank_sin; /* struct copy */ 328 if (getinetaddr(host, &sin->sin_addr) == -1) 329 exit(1); 330 dump(sin->sin_addr.s_addr); 331 if (found_entry == 0) { 332 (void)printf("%s (%s) -- no entry\n", host, 333 inet_ntoa(sin->sin_addr)); 334 exit(1); 335 } 336 } 337 338 /* 339 * Delete an arp entry 340 */ 341 int 342 delete(host, info) 343 const char *host; 344 const char *info; 345 { 346 struct sockaddr_inarp *sin; 347 struct rt_msghdr *rtm; 348 struct sockaddr_dl *sdl; 349 350 sin = &sin_m; 351 rtm = &m_rtmsg.m_rtm; 352 353 if (info && strncmp(info, "pro", 3) ) 354 export_only = 1; 355 getsocket(); 356 sin_m = blank_sin; /* struct copy */ 357 if (getinetaddr(host, &sin->sin_addr) == -1) 358 return (1); 359 tryagain: 360 if (rtmsg(RTM_GET) < 0) { 361 warn("%s", host); 362 return (1); 363 } 364 sin = (struct sockaddr_inarp *)(rtm + 1); 365 sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 366 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 367 if (sdl->sdl_family == AF_LINK && 368 (rtm->rtm_flags & RTF_LLINFO) && 369 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 370 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 371 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 372 goto delete; 373 } 374 } 375 if (sin_m.sin_other & SIN_PROXY) { 376 warnx("delete: can't locate %s", host); 377 return (1); 378 } else { 379 sin_m.sin_other = SIN_PROXY; 380 goto tryagain; 381 } 382 delete: 383 if (sdl->sdl_family != AF_LINK) { 384 (void)printf("cannot locate %s\n", host); 385 return (1); 386 } 387 if (rtmsg(RTM_DELETE)) 388 return (1); 389 if (vflag) 390 (void)printf("%s (%s) deleted\n", host, 391 inet_ntoa(sin->sin_addr)); 392 return (0); 393 } 394 395 /* 396 * Dump the entire arp table 397 */ 398 void 399 dump(addr) 400 u_long addr; 401 { 402 int mib[6]; 403 size_t needed; 404 char ifname[IFNAMSIZ]; 405 char *host, *lim, *buf, *next; 406 struct rt_msghdr *rtm; 407 struct sockaddr_inarp *sin; 408 struct sockaddr_dl *sdl; 409 struct hostent *hp; 410 411 mib[0] = CTL_NET; 412 mib[1] = PF_ROUTE; 413 mib[2] = 0; 414 mib[3] = AF_INET; 415 mib[4] = NET_RT_FLAGS; 416 mib[5] = RTF_LLINFO; 417 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 418 err(1, "route-sysctl-estimate"); 419 if (needed == 0) 420 return; 421 if ((buf = malloc(needed)) == NULL) 422 err(1, "malloc"); 423 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 424 err(1, "actual retrieval of routing table"); 425 lim = buf + needed; 426 for (next = buf; next < lim; next += rtm->rtm_msglen) { 427 rtm = (struct rt_msghdr *)next; 428 sin = (struct sockaddr_inarp *)(rtm + 1); 429 sdl = (struct sockaddr_dl *) 430 (ROUNDUP(sin->sin_len) + (char *)sin); 431 if (addr) { 432 if (addr != sin->sin_addr.s_addr) 433 continue; 434 found_entry = 1; 435 } 436 if (nflag == 0) 437 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 438 sizeof sin->sin_addr, AF_INET); 439 else 440 hp = NULL; 441 442 host = hp ? hp->h_name : "?"; 443 444 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 445 if (sdl->sdl_alen) 446 sdl_print(sdl); 447 else 448 (void)printf("(incomplete)"); 449 450 if (sdl->sdl_index) { 451 if (getifname(sdl->sdl_index, ifname) == 0) 452 printf(" on %s", ifname); 453 } 454 455 if (rtm->rtm_rmx.rmx_expire == 0) 456 (void)printf(" permanent"); 457 if (sin->sin_other & SIN_PROXY) 458 (void)printf(" published (proxy only)"); 459 if (rtm->rtm_addrs & RTA_NETMASK) { 460 sin = (struct sockaddr_inarp *) 461 (ROUNDUP(sdl->sdl_len) + (char *)sdl); 462 if (sin->sin_addr.s_addr == 0xffffffff) 463 (void)printf(" published"); 464 if (sin->sin_len != 8) 465 (void)printf("(weird)"); 466 } 467 (void)printf("\n"); 468 } 469 } 470 471 /* 472 * Delete the entire arp table 473 */ 474 void 475 delete_all(void) 476 { 477 int mib[6]; 478 size_t needed; 479 char addr[sizeof("000.000.000.000\0")]; 480 char *lim, *buf, *next; 481 struct rt_msghdr *rtm; 482 struct sockaddr_inarp *sin; 483 struct sockaddr_dl *sdl; 484 485 mib[0] = CTL_NET; 486 mib[1] = PF_ROUTE; 487 mib[2] = 0; 488 mib[3] = AF_INET; 489 mib[4] = NET_RT_FLAGS; 490 mib[5] = RTF_LLINFO; 491 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 492 err(1, "route-sysctl-estimate"); 493 if (needed == 0) 494 return; 495 if ((buf = malloc(needed)) == NULL) 496 err(1, "malloc"); 497 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 498 err(1, "actual retrieval of routing table"); 499 lim = buf + needed; 500 for (next = buf; next < lim; next += rtm->rtm_msglen) { 501 rtm = (struct rt_msghdr *)next; 502 sin = (struct sockaddr_inarp *)(rtm + 1); 503 sdl = (struct sockaddr_dl *) 504 (ROUNDUP(sin->sin_len) + (char *)sin); 505 snprintf(addr, sizeof(addr), "%s", inet_ntoa(sin->sin_addr)); 506 delete(addr, NULL); 507 } 508 } 509 510 void 511 sdl_print(sdl) 512 const struct sockaddr_dl *sdl; 513 { 514 char hbuf[NI_MAXHOST]; 515 516 if (getnameinfo((struct sockaddr *)sdl, sdl->sdl_len, 517 hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) 518 printf("<invalid>"); 519 else 520 printf("%s", hbuf); 521 } 522 523 int 524 atosdl(s, sdl) 525 const char *s; 526 struct sockaddr_dl *sdl; 527 { 528 int i; 529 long b; 530 caddr_t endp; 531 caddr_t p; 532 char *t, *r; 533 534 p = LLADDR(sdl); 535 endp = ((caddr_t)sdl) + sdl->sdl_len; 536 i = 0; 537 538 b = strtol(s, &t, 16); 539 if (t == s) 540 return 1; 541 542 *p++ = b; 543 ++i; 544 while ((p < endp) && (*t++ == ':')) { 545 b = strtol(t, &r, 16); 546 if (r == t) 547 break; 548 *p++ = b; 549 ++i; 550 t = r; 551 } 552 sdl->sdl_alen = i; 553 554 return 0; 555 } 556 557 void 558 usage() 559 { 560 const char *progname; 561 562 progname = getprogname(); 563 (void)fprintf(stderr, "usage: %s [-n] hostname\n", progname); 564 (void)fprintf(stderr, "usage: %s [-n] -a\n", progname); 565 (void)fprintf(stderr, "usage: %s -d [-a|hostname]\n", progname); 566 (void)fprintf(stderr, 567 "usage: %s -s hostname ether_addr [temp] [pub]\n", progname); 568 (void)fprintf(stderr, "usage: %s -f filename\n", progname); 569 exit(1); 570 } 571 572 int 573 rtmsg(cmd) 574 int cmd; 575 { 576 static int seq; 577 int rlen; 578 struct rt_msghdr *rtm; 579 char *cp; 580 int l; 581 582 rtm = &m_rtmsg.m_rtm; 583 cp = m_rtmsg.m_space; 584 errno = 0; 585 586 if (cmd == RTM_DELETE) 587 goto doit; 588 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 589 rtm->rtm_flags = flags; 590 rtm->rtm_version = RTM_VERSION; 591 592 switch (cmd) { 593 default: 594 errx(1, "internal wrong cmd"); 595 /*NOTREACHED*/ 596 case RTM_ADD: 597 rtm->rtm_addrs |= RTA_GATEWAY; 598 rtm->rtm_rmx.rmx_expire = expire_time; 599 rtm->rtm_inits = RTV_EXPIRE; 600 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 601 sin_m.sin_other = 0; 602 if (doing_proxy) { 603 if (export_only) 604 sin_m.sin_other = SIN_PROXY; 605 else { 606 rtm->rtm_addrs |= RTA_NETMASK; 607 rtm->rtm_flags &= ~RTF_HOST; 608 } 609 } 610 /* FALLTHROUGH */ 611 case RTM_GET: 612 rtm->rtm_addrs |= RTA_DST; 613 } 614 615 #define NEXTADDR(w, s) \ 616 if (rtm->rtm_addrs & (w)) { \ 617 (void)memcpy(cp, &s, ((struct sockaddr *)&s)->sa_len); \ 618 cp += ROUNDUP(((struct sockaddr *)&s)->sa_len); \ 619 } 620 621 NEXTADDR(RTA_DST, sin_m); 622 NEXTADDR(RTA_GATEWAY, sdl_m); 623 NEXTADDR(RTA_NETMASK, so_mask); 624 625 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 626 doit: 627 l = rtm->rtm_msglen; 628 rtm->rtm_seq = ++seq; 629 rtm->rtm_type = cmd; 630 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 631 if (errno != ESRCH || cmd != RTM_DELETE) { 632 warn("writing to routing socket"); 633 return (-1); 634 } 635 } 636 do { 637 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 638 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 639 if (l < 0) 640 warn("read from routing socket"); 641 return (0); 642 } 643 644 int 645 getinetaddr(host, inap) 646 const char *host; 647 struct in_addr *inap; 648 { 649 struct hostent *hp; 650 651 if (inet_aton(host, inap) == 1) 652 return (0); 653 if ((hp = gethostbyname(host)) == NULL) { 654 warnx("%s: %s", host, hstrerror(h_errno)); 655 return (-1); 656 } 657 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 658 return (0); 659 } 660 661 int 662 getifname(ifindex, ifname) 663 u_int16_t ifindex; 664 char* ifname; 665 { 666 int i, idx, siz; 667 char ifrbuf[8192]; 668 struct ifreq ifreq, *ifr; 669 const struct sockaddr_dl *sdl = NULL; 670 671 if (is < 0) { 672 is = socket(PF_INET, SOCK_DGRAM, 0); 673 if (is < 0) 674 err(1, "socket"); 675 676 ifc.ifc_len = sizeof(ifconfbuf); 677 ifc.ifc_buf = ifconfbuf; 678 679 if (ioctl(is, SIOCGIFCONF, &ifc) < 0) { 680 close(is); 681 err(1, "SIOCGIFCONF"); 682 is = -1; 683 } 684 } 685 686 ifr = ifc.ifc_req; 687 ifreq.ifr_name[0] = '\0'; 688 for (i = 0, idx = 0; i < ifc.ifc_len; ) { 689 ifr = (struct ifreq *)((caddr_t)ifc.ifc_req + i); 690 siz = sizeof(ifr->ifr_name) + 691 (ifr->ifr_addr.sa_len > sizeof(struct sockaddr) 692 ? ifr->ifr_addr.sa_len 693 : sizeof(struct sockaddr)); 694 i += siz; 695 /* avoid alignment issue */ 696 if (sizeof(ifrbuf) < siz) 697 errx(1, "ifr too big"); 698 699 memcpy(ifrbuf, ifr, siz); 700 ifr = (struct ifreq *)ifrbuf; 701 702 if (ifr->ifr_addr.sa_family != AF_LINK) 703 continue; 704 705 sdl = (const struct sockaddr_dl *) &ifr->ifr_addr; 706 if (sdl && sdl->sdl_index == ifindex) { 707 (void) strncpy(ifname, ifr->ifr_name, IFNAMSIZ); 708 return 0; 709 } 710 } 711 712 return -1; 713 } 714
Indexes created Tue Sep 30 17:09:57 GMT 2025