arp.c revision 1.40
1 /* $NetBSD: arp.c,v 1.40 2004/08/14 02:16:13 jrf 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #ifndef lint 37 __COPYRIGHT("@(#) Copyright (c) 1984, 1993\n\ 38 The Regents of the University of California. All rights reserved.\n"); 39 #endif /* not lint */ 40 41 #ifndef lint 42 #if 0 43 static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; 44 #else 45 __RCSID("$NetBSD: arp.c,v 1.40 2004/08/14 02:16:13 jrf Exp $"); 46 #endif 47 #endif /* not lint */ 48 49 /* 50 * arp - display, set, and delete arp table entries 51 */ 52 53 /* Roundup the same way rt_xaddrs does */ 54 #define ROUNDUP(a) \ 55 ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) 56 57 #include <sys/param.h> 58 #include <sys/file.h> 59 #include <sys/socket.h> 60 #include <sys/sysctl.h> 61 #include <sys/ioctl.h> 62 63 #include <net/if.h> 64 #include <net/if_dl.h> 65 #include <net/if_ether.h> 66 #include <net/if_types.h> 67 #include <net/route.h> 68 #include <netinet/in.h> 69 #include <netinet/if_inarp.h> 70 #include <arpa/inet.h> 71 72 #include <err.h> 73 #include <errno.h> 74 #include <netdb.h> 75 #include <nlist.h> 76 #include <paths.h> 77 #include <stdio.h> 78 #include <stdlib.h> 79 #include <string.h> 80 #include <unistd.h> 81 #include <ifaddrs.h> 82 83 int delete __P((const char *, const char *)); 84 void dump __P((u_long)); 85 void delete_all __P((void)); 86 void sdl_print __P((const struct sockaddr_dl *)); 87 int getifname __P((u_int16_t, char *, size_t)); 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 aflag, nflag, vflag; 100 static int s = -1; 101 static struct ifaddrs* ifaddrs = NULL; 102 103 int 104 main(argc, argv) 105 int argc; 106 char **argv; 107 { 108 int ch; 109 int op = 0; 110 111 setprogname(argv[0]); 112 113 pid = getpid(); 114 115 while ((ch = getopt(argc, argv, "andsfv")) != -1) 116 switch((char)ch) { 117 case 'a': 118 aflag = 1; 119 break; 120 case 'd': 121 case 's': 122 case 'f': 123 if (op) 124 usage(); 125 op = ch; 126 break; 127 case 'n': 128 nflag = 1; 129 break; 130 case 'v': 131 vflag = 1; 132 break; 133 default: 134 usage(); 135 } 136 argc -= optind; 137 argv += optind; 138 139 if (!op && aflag) 140 op = 'a'; 141 142 switch((char)op) { 143 case 'a': 144 dump(0); 145 break; 146 case 'd': 147 if (aflag && argc == 0) 148 delete_all(); 149 else { 150 if (aflag || argc < 1 || argc > 2) 151 usage(); 152 (void)delete(argv[0], argv[1]); 153 } 154 break; 155 case 's': 156 if (argc < 2 || argc > 5) 157 usage(); 158 return (set(argc, argv) ? 1 : 0); 159 case 'f': 160 if (argc != 1) 161 usage(); 162 return (file(argv[0])); 163 default: 164 if (argc != 1) 165 usage(); 166 get(argv[0]); 167 break; 168 } 169 return (0); 170 } 171 172 /* 173 * Process a file to set standard arp entries 174 */ 175 int 176 file(name) 177 char *name; 178 { 179 char line[100], arg[5][50], *args[5]; 180 int i, retval; 181 FILE *fp; 182 183 if ((fp = fopen(name, "r")) == NULL) 184 err(1, "cannot open %s", name); 185 args[0] = &arg[0][0]; 186 args[1] = &arg[1][0]; 187 args[2] = &arg[2][0]; 188 args[3] = &arg[3][0]; 189 args[4] = &arg[4][0]; 190 retval = 0; 191 while (fgets(line, 100, fp) != NULL) { 192 i = sscanf(line, "%49s %49s %49s %49s %49s", 193 arg[0], arg[1], arg[2], arg[3], arg[4]); 194 if (i < 2) { 195 warnx("bad line: %s", line); 196 retval = 1; 197 continue; 198 } 199 if (set(i, args)) 200 retval = 1; 201 } 202 fclose(fp); 203 return (retval); 204 } 205 206 void 207 getsocket() 208 { 209 if (s >= 0) 210 return; 211 s = socket(PF_ROUTE, SOCK_RAW, 0); 212 if (s < 0) 213 err(1, "socket"); 214 } 215 216 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 217 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 218 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 219 int expire_time, flags, export_only, doing_proxy, found_entry; 220 struct { 221 struct rt_msghdr m_rtm; 222 char m_space[512]; 223 } m_rtmsg; 224 225 /* 226 * Set an individual arp entry 227 */ 228 int 229 set(argc, argv) 230 int argc; 231 char **argv; 232 { 233 struct sockaddr_inarp *sin; 234 struct sockaddr_dl *sdl; 235 struct rt_msghdr *rtm; 236 char *host = argv[0], *eaddr; 237 int rval; 238 239 sin = &sin_m; 240 rtm = &(m_rtmsg.m_rtm); 241 eaddr = argv[1]; 242 243 getsocket(); 244 argc -= 2; 245 argv += 2; 246 sdl_m = blank_sdl; /* struct copy */ 247 sin_m = blank_sin; /* struct copy */ 248 if (getinetaddr(host, &sin->sin_addr) == -1) 249 return (1); 250 if (atosdl(eaddr, &sdl_m)) 251 warnx("invalid link-level address '%s'", eaddr); 252 doing_proxy = flags = export_only = expire_time = 0; 253 while (argc-- > 0) { 254 if (strncmp(argv[0], "temp", 4) == 0) { 255 struct timeval time; 256 (void)gettimeofday(&time, 0); 257 expire_time = time.tv_sec + 20 * 60; 258 } 259 else if (strncmp(argv[0], "pub", 3) == 0) { 260 flags |= RTF_ANNOUNCE; 261 doing_proxy = SIN_PROXY; 262 } else if (strncmp(argv[0], "trail", 5) == 0) { 263 (void)printf( 264 "%s: Sending trailers is no longer supported\n", 265 host); 266 } 267 argv++; 268 } 269 tryagain: 270 if (rtmsg(RTM_GET) < 0) { 271 warn("%s", host); 272 return (1); 273 } 274 sin = (struct sockaddr_inarp *)(rtm + 1); 275 sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 276 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 277 if (sdl->sdl_family == AF_LINK && 278 (rtm->rtm_flags & RTF_LLINFO) && 279 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 280 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 281 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 282 goto overwrite; 283 } 284 if (doing_proxy == 0) { 285 (void)printf("set: can only proxy for %s\n", host); 286 return (1); 287 } 288 if (sin_m.sin_other & SIN_PROXY) { 289 (void)printf( 290 "set: proxy entry exists for non 802 device\n"); 291 return (1); 292 } 293 sin_m.sin_other = SIN_PROXY; 294 export_only = 1; 295 goto tryagain; 296 } 297 overwrite: 298 if (sdl->sdl_family != AF_LINK) { 299 (void)printf("cannot intuit interface index and type for %s\n", 300 host); 301 return (1); 302 } 303 sdl_m.sdl_type = sdl->sdl_type; 304 sdl_m.sdl_index = sdl->sdl_index; 305 rval = rtmsg(RTM_ADD); 306 if (vflag) 307 (void)printf("%s (%s) added\n", host, eaddr); 308 return (rval); 309 } 310 311 /* 312 * Display an individual arp entry 313 */ 314 void 315 get(host) 316 const char *host; 317 { 318 struct sockaddr_inarp *sin; 319 320 sin = &sin_m; 321 sin_m = blank_sin; /* struct copy */ 322 if (getinetaddr(host, &sin->sin_addr) == -1) 323 exit(1); 324 dump(sin->sin_addr.s_addr); 325 if (found_entry == 0) { 326 (void)printf("%s (%s) -- no entry\n", host, 327 inet_ntoa(sin->sin_addr)); 328 exit(1); 329 } 330 } 331 332 /* 333 * Delete an arp entry 334 */ 335 int 336 delete(host, info) 337 const char *host; 338 const char *info; 339 { 340 struct sockaddr_inarp *sin; 341 struct rt_msghdr *rtm; 342 struct sockaddr_dl *sdl; 343 344 sin = &sin_m; 345 rtm = &m_rtmsg.m_rtm; 346 347 if (info && strncmp(info, "pro", 3) ) 348 export_only = 1; 349 getsocket(); 350 sin_m = blank_sin; /* struct copy */ 351 if (getinetaddr(host, &sin->sin_addr) == -1) 352 return (1); 353 tryagain: 354 if (rtmsg(RTM_GET) < 0) { 355 warn("%s", host); 356 return (1); 357 } 358 sin = (struct sockaddr_inarp *)(rtm + 1); 359 sdl = (struct sockaddr_dl *)(ROUNDUP(sin->sin_len) + (char *)sin); 360 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 361 if (sdl->sdl_family == AF_LINK && 362 (rtm->rtm_flags & RTF_LLINFO) && 363 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 364 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 365 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 366 goto delete; 367 } 368 } 369 if (sin_m.sin_other & SIN_PROXY) { 370 warnx("delete: can't locate %s", host); 371 return (1); 372 } else { 373 sin_m.sin_other = SIN_PROXY; 374 goto tryagain; 375 } 376 delete: 377 if (sdl->sdl_family != AF_LINK) { 378 (void)printf("cannot locate %s\n", host); 379 return (1); 380 } 381 if (rtmsg(RTM_DELETE)) 382 return (1); 383 if (vflag) 384 (void)printf("%s (%s) deleted\n", host, 385 inet_ntoa(sin->sin_addr)); 386 return (0); 387 } 388 389 /* 390 * Dump the entire arp table 391 */ 392 void 393 dump(addr) 394 u_long addr; 395 { 396 int mib[6]; 397 size_t needed; 398 char ifname[IFNAMSIZ]; 399 char *host, *lim, *buf, *next; 400 struct rt_msghdr *rtm; 401 struct sockaddr_inarp *sin; 402 struct sockaddr_dl *sdl; 403 struct hostent *hp; 404 405 mib[0] = CTL_NET; 406 mib[1] = PF_ROUTE; 407 mib[2] = 0; 408 mib[3] = AF_INET; 409 mib[4] = NET_RT_FLAGS; 410 mib[5] = RTF_LLINFO; 411 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 412 err(1, "route-sysctl-estimate"); 413 if (needed == 0) 414 return; 415 if ((buf = malloc(needed)) == NULL) 416 err(1, "malloc"); 417 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 418 err(1, "actual retrieval of routing table"); 419 lim = buf + needed; 420 for (next = buf; next < lim; next += rtm->rtm_msglen) { 421 rtm = (struct rt_msghdr *)next; 422 sin = (struct sockaddr_inarp *)(rtm + 1); 423 sdl = (struct sockaddr_dl *) 424 (ROUNDUP(sin->sin_len) + (char *)sin); 425 if (addr) { 426 if (addr != sin->sin_addr.s_addr) 427 continue; 428 found_entry = 1; 429 } 430 if (nflag == 0) 431 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 432 sizeof sin->sin_addr, AF_INET); 433 else 434 hp = NULL; 435 436 host = hp ? hp->h_name : "?"; 437 438 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 439 if (sdl->sdl_alen) 440 sdl_print(sdl); 441 else 442 (void)printf("(incomplete)"); 443 444 if (sdl->sdl_index) { 445 if (getifname(sdl->sdl_index, ifname, sizeof(ifname)) == 0) 446 printf(" on %s", ifname); 447 } 448 449 if (rtm->rtm_rmx.rmx_expire == 0) 450 (void)printf(" permanent"); 451 if (sin->sin_other & SIN_PROXY) 452 (void)printf(" published (proxy only)"); 453 if (rtm->rtm_addrs & RTA_NETMASK) { 454 sin = (struct sockaddr_inarp *) 455 (ROUNDUP(sdl->sdl_len) + (char *)sdl); 456 if (sin->sin_addr.s_addr == 0xffffffff) 457 (void)printf(" published"); 458 if (sin->sin_len != 8) 459 (void)printf("(weird)"); 460 } 461 (void)printf("\n"); 462 } 463 free(buf); 464 } 465 466 /* 467 * Delete the entire arp table 468 */ 469 void 470 delete_all(void) 471 { 472 int mib[6]; 473 size_t needed; 474 char addr[sizeof("000.000.000.000\0")]; 475 char *lim, *buf, *next; 476 struct rt_msghdr *rtm; 477 struct sockaddr_inarp *sin; 478 struct sockaddr_dl *sdl; 479 480 mib[0] = CTL_NET; 481 mib[1] = PF_ROUTE; 482 mib[2] = 0; 483 mib[3] = AF_INET; 484 mib[4] = NET_RT_FLAGS; 485 mib[5] = RTF_LLINFO; 486 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 487 err(1, "route-sysctl-estimate"); 488 if (needed == 0) 489 return; 490 if ((buf = malloc(needed)) == NULL) 491 err(1, "malloc"); 492 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 493 err(1, "actual retrieval of routing table"); 494 lim = buf + needed; 495 for (next = buf; next < lim; next += rtm->rtm_msglen) { 496 rtm = (struct rt_msghdr *)next; 497 sin = (struct sockaddr_inarp *)(rtm + 1); 498 sdl = (struct sockaddr_dl *) 499 (ROUNDUP(sin->sin_len) + (char *)sin); 500 snprintf(addr, sizeof(addr), "%s", inet_ntoa(sin->sin_addr)); 501 delete(addr, NULL); 502 } 503 free(buf); 504 } 505 506 void 507 sdl_print(sdl) 508 const struct sockaddr_dl *sdl; 509 { 510 char hbuf[NI_MAXHOST]; 511 512 if (getnameinfo((struct sockaddr *)sdl, sdl->sdl_len, 513 hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) 514 printf("<invalid>"); 515 else 516 printf("%s", hbuf); 517 } 518 519 int 520 atosdl(s, sdl) 521 const char *s; 522 struct sockaddr_dl *sdl; 523 { 524 int i; 525 long b; 526 caddr_t endp; 527 caddr_t p; 528 char *t, *r; 529 530 p = LLADDR(sdl); 531 endp = ((caddr_t)sdl) + sdl->sdl_len; 532 i = 0; 533 534 b = strtol(s, &t, 16); 535 if (t == s) 536 return 1; 537 538 *p++ = b; 539 ++i; 540 while ((p < endp) && (*t++ == ':')) { 541 b = strtol(t, &r, 16); 542 if (r == t) 543 break; 544 *p++ = b; 545 ++i; 546 t = r; 547 } 548 sdl->sdl_alen = i; 549 550 return 0; 551 } 552 553 void 554 usage() 555 { 556 const char *progname; 557 558 progname = getprogname(); 559 (void)fprintf(stderr, "usage: %s [-n] hostname\n", progname); 560 (void)fprintf(stderr, "usage: %s [-nv] -a\n", progname); 561 (void)fprintf(stderr, "usage: %s [-v] -d [-a|hostname]\n", progname); 562 (void)fprintf(stderr, 563 "usage: %s -s hostname ether_addr [temp] [pub]\n", progname); 564 (void)fprintf(stderr, "usage: %s -f filename\n", progname); 565 exit(1); 566 } 567 568 int 569 rtmsg(cmd) 570 int cmd; 571 { 572 static int seq; 573 int rlen; 574 struct rt_msghdr *rtm; 575 char *cp; 576 int l; 577 578 rtm = &m_rtmsg.m_rtm; 579 cp = m_rtmsg.m_space; 580 errno = 0; 581 582 if (cmd == RTM_DELETE) 583 goto doit; 584 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 585 rtm->rtm_flags = flags; 586 rtm->rtm_version = RTM_VERSION; 587 588 switch (cmd) { 589 default: 590 errx(1, "internal wrong cmd"); 591 /*NOTREACHED*/ 592 case RTM_ADD: 593 rtm->rtm_addrs |= RTA_GATEWAY; 594 rtm->rtm_rmx.rmx_expire = expire_time; 595 rtm->rtm_inits = RTV_EXPIRE; 596 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 597 sin_m.sin_other = 0; 598 if (doing_proxy) { 599 if (export_only) 600 sin_m.sin_other = SIN_PROXY; 601 else { 602 rtm->rtm_addrs |= RTA_NETMASK; 603 rtm->rtm_flags &= ~RTF_HOST; 604 } 605 } 606 /* FALLTHROUGH */ 607 case RTM_GET: 608 rtm->rtm_addrs |= RTA_DST; 609 } 610 611 #define NEXTADDR(w, s) \ 612 if (rtm->rtm_addrs & (w)) { \ 613 (void)memcpy(cp, &s, ((struct sockaddr *)&s)->sa_len); \ 614 cp += ROUNDUP(((struct sockaddr *)&s)->sa_len); \ 615 } 616 617 NEXTADDR(RTA_DST, sin_m); 618 NEXTADDR(RTA_GATEWAY, sdl_m); 619 NEXTADDR(RTA_NETMASK, so_mask); 620 621 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 622 doit: 623 l = rtm->rtm_msglen; 624 rtm->rtm_seq = ++seq; 625 rtm->rtm_type = cmd; 626 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 627 if (errno != ESRCH || cmd != RTM_DELETE) { 628 warn("writing to routing socket"); 629 return (-1); 630 } 631 } 632 do { 633 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 634 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 635 if (l < 0) 636 warn("read from routing socket"); 637 return (0); 638 } 639 640 int 641 getinetaddr(host, inap) 642 const char *host; 643 struct in_addr *inap; 644 { 645 struct hostent *hp; 646 647 if (inet_aton(host, inap) == 1) 648 return (0); 649 if ((hp = gethostbyname(host)) == NULL) { 650 warnx("%s: %s", host, hstrerror(h_errno)); 651 return (-1); 652 } 653 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 654 return (0); 655 } 656 657 int 658 getifname(ifindex, ifname, l) 659 u_int16_t ifindex; 660 char* ifname; 661 size_t l; 662 { 663 int i; 664 struct ifaddrs *addr; 665 const struct sockaddr_dl *sdl = NULL; 666 667 if (ifaddrs == NULL) { 668 i = getifaddrs(&ifaddrs); 669 if (i != 0) 670 err(1, "getifaddrs"); 671 } 672 673 for (addr = ifaddrs; addr; addr = addr->ifa_next) { 674 if (addr->ifa_addr == NULL || 675 addr->ifa_addr->sa_family != AF_LINK) 676 continue; 677 678 sdl = (const struct sockaddr_dl *) addr->ifa_addr; 679 if (sdl && sdl->sdl_index == ifindex) { 680 (void) strlcpy(ifname, addr->ifa_name, l); 681 return 0; 682 } 683 } 684 685 return -1; 686 } 687
Indexes created Tue Sep 30 20:09:53 GMT 2025