arp.c revision 1.41
1 /* $NetBSD: arp.c,v 1.41 2005/03/16 02:04:51 xtraeme 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 1.41 2005/03/16 02:04:51 xtraeme 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(const char *, const char *); 84 void dump(u_long); 85 void delete_all(void); 86 void sdl_print(const struct sockaddr_dl *); 87 int getifname(u_int16_t, char *, size_t); 88 int atosdl(const char *s, struct sockaddr_dl *sdl); 89 int file(char *); 90 void get(const char *); 91 int getinetaddr(const char *, struct in_addr *); 92 void getsocket(void); 93 int rtmsg(int); 94 int set(int, char **); 95 void usage(void); 96 97 static int pid; 98 static int aflag, nflag, vflag; 99 static int s = -1; 100 static struct ifaddrs* ifaddrs = NULL; 101 102 int 103 main(int argc, char **argv) 104 { 105 int ch; 106 int op = 0; 107 108 setprogname(argv[0]); 109 110 pid = getpid(); 111 112 while ((ch = getopt(argc, argv, "andsfv")) != -1) 113 switch((char)ch) { 114 case 'a': 115 aflag = 1; 116 break; 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 if (!op && aflag) 137 op = 'a'; 138 139 switch((char)op) { 140 case 'a': 141 dump(0); 142 break; 143 case 'd': 144 if (aflag && argc == 0) 145 delete_all(); 146 else { 147 if (aflag || argc < 1 || argc > 2) 148 usage(); 149 (void)delete(argv[0], argv[1]); 150 } 151 break; 152 case 's': 153 if (argc < 2 || argc > 5) 154 usage(); 155 return (set(argc, argv) ? 1 : 0); 156 case 'f': 157 if (argc != 1) 158 usage(); 159 return (file(argv[0])); 160 default: 161 if (argc != 1) 162 usage(); 163 get(argv[0]); 164 break; 165 } 166 return (0); 167 } 168 169 /* 170 * Process a file to set standard arp entries 171 */ 172 int 173 file(char *name) 174 { 175 char line[100], arg[5][50], *args[5]; 176 int i, retval; 177 FILE *fp; 178 179 if ((fp = fopen(name, "r")) == NULL) 180 err(1, "cannot open %s", name); 181 args[0] = &arg[0][0]; 182 args[1] = &arg[1][0]; 183 args[2] = &arg[2][0]; 184 args[3] = &arg[3][0]; 185 args[4] = &arg[4][0]; 186 retval = 0; 187 while (fgets(line, 100, fp) != NULL) { 188 i = sscanf(line, "%49s %49s %49s %49s %49s", 189 arg[0], arg[1], arg[2], arg[3], arg[4]); 190 if (i < 2) { 191 warnx("bad line: %s", line); 192 retval = 1; 193 continue; 194 } 195 if (set(i, args)) 196 retval = 1; 197 } 198 fclose(fp); 199 return (retval); 200 } 201 202 void 203 getsocket(void) 204 { 205 if (s >= 0) 206 return; 207 s = socket(PF_ROUTE, SOCK_RAW, 0); 208 if (s < 0) 209 err(1, "socket"); 210 } 211 212 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 213 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 214 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 215 int expire_time, flags, export_only, doing_proxy, found_entry; 216 struct { 217 struct rt_msghdr m_rtm; 218 char m_space[512]; 219 } m_rtmsg; 220 221 /* 222 * Set an individual arp entry 223 */ 224 int 225 set(int argc, char **argv) 226 { 227 struct sockaddr_inarp *sina; 228 struct sockaddr_dl *sdl; 229 struct rt_msghdr *rtm; 230 char *host = argv[0], *eaddr; 231 int rval; 232 233 sina = &sin_m; 234 rtm = &(m_rtmsg.m_rtm); 235 eaddr = argv[1]; 236 237 getsocket(); 238 argc -= 2; 239 argv += 2; 240 sdl_m = blank_sdl; /* struct copy */ 241 sin_m = blank_sin; /* struct copy */ 242 if (getinetaddr(host, &sina->sin_addr) == -1) 243 return (1); 244 if (atosdl(eaddr, &sdl_m)) 245 warnx("invalid link-level address '%s'", eaddr); 246 doing_proxy = flags = export_only = expire_time = 0; 247 while (argc-- > 0) { 248 if (strncmp(argv[0], "temp", 4) == 0) { 249 struct timeval timev; 250 (void)gettimeofday(&timev, 0); 251 expire_time = timev.tv_sec + 20 * 60; 252 } 253 else if (strncmp(argv[0], "pub", 3) == 0) { 254 flags |= RTF_ANNOUNCE; 255 doing_proxy = SIN_PROXY; 256 } else if (strncmp(argv[0], "trail", 5) == 0) { 257 (void)printf( 258 "%s: Sending trailers is no longer supported\n", 259 host); 260 } 261 argv++; 262 } 263 tryagain: 264 if (rtmsg(RTM_GET) < 0) { 265 warn("%s", host); 266 return (1); 267 } 268 sina = (struct sockaddr_inarp *)(rtm + 1); 269 sdl = (struct sockaddr_dl *)(ROUNDUP(sina->sin_len) + (char *)sina); 270 if (sina->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 271 if (sdl->sdl_family == AF_LINK && 272 (rtm->rtm_flags & RTF_LLINFO) && 273 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 274 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 275 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 276 goto overwrite; 277 } 278 if (doing_proxy == 0) { 279 (void)printf("set: can only proxy for %s\n", host); 280 return (1); 281 } 282 if (sin_m.sin_other & SIN_PROXY) { 283 (void)printf( 284 "set: proxy entry exists for non 802 device\n"); 285 return (1); 286 } 287 sin_m.sin_other = SIN_PROXY; 288 export_only = 1; 289 goto tryagain; 290 } 291 overwrite: 292 if (sdl->sdl_family != AF_LINK) { 293 (void)printf("cannot intuit interface index and type for %s\n", 294 host); 295 return (1); 296 } 297 sdl_m.sdl_type = sdl->sdl_type; 298 sdl_m.sdl_index = sdl->sdl_index; 299 rval = rtmsg(RTM_ADD); 300 if (vflag) 301 (void)printf("%s (%s) added\n", host, eaddr); 302 return (rval); 303 } 304 305 /* 306 * Display an individual arp entry 307 */ 308 void 309 get(const char *host) 310 { 311 struct sockaddr_inarp *sina; 312 313 sina = &sin_m; 314 sin_m = blank_sin; /* struct copy */ 315 if (getinetaddr(host, &sina->sin_addr) == -1) 316 exit(1); 317 dump(sina->sin_addr.s_addr); 318 if (found_entry == 0) { 319 (void)printf("%s (%s) -- no entry\n", host, 320 inet_ntoa(sina->sin_addr)); 321 exit(1); 322 } 323 } 324 325 /* 326 * Delete an arp entry 327 */ 328 int 329 delete(const char *host, const char *info) 330 { 331 struct sockaddr_inarp *sina; 332 struct rt_msghdr *rtm; 333 struct sockaddr_dl *sdl; 334 335 sina = &sin_m; 336 rtm = &m_rtmsg.m_rtm; 337 338 if (info && strncmp(info, "pro", 3) ) 339 export_only = 1; 340 getsocket(); 341 sin_m = blank_sin; /* struct copy */ 342 if (getinetaddr(host, &sina->sin_addr) == -1) 343 return (1); 344 tryagain: 345 if (rtmsg(RTM_GET) < 0) { 346 warn("%s", host); 347 return (1); 348 } 349 sina = (struct sockaddr_inarp *)(rtm + 1); 350 sdl = (struct sockaddr_dl *)(ROUNDUP(sina->sin_len) + (char *)sina); 351 if (sina->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 352 if (sdl->sdl_family == AF_LINK && 353 (rtm->rtm_flags & RTF_LLINFO) && 354 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 355 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 356 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 357 goto delete; 358 } 359 } 360 if (sin_m.sin_other & SIN_PROXY) { 361 warnx("delete: can't locate %s", host); 362 return (1); 363 } else { 364 sin_m.sin_other = SIN_PROXY; 365 goto tryagain; 366 } 367 delete: 368 if (sdl->sdl_family != AF_LINK) { 369 (void)printf("cannot locate %s\n", host); 370 return (1); 371 } 372 if (rtmsg(RTM_DELETE)) 373 return (1); 374 if (vflag) 375 (void)printf("%s (%s) deleted\n", host, 376 inet_ntoa(sina->sin_addr)); 377 return (0); 378 } 379 380 /* 381 * Dump the entire arp table 382 */ 383 void 384 dump(u_long addr) 385 { 386 int mib[6]; 387 size_t needed; 388 char ifname[IFNAMSIZ]; 389 char *lim, *buf, *next; 390 const char *host; 391 struct rt_msghdr *rtm; 392 struct sockaddr_inarp *sina; 393 struct sockaddr_dl *sdl; 394 struct hostent *hp; 395 396 mib[0] = CTL_NET; 397 mib[1] = PF_ROUTE; 398 mib[2] = 0; 399 mib[3] = AF_INET; 400 mib[4] = NET_RT_FLAGS; 401 mib[5] = RTF_LLINFO; 402 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 403 err(1, "route-sysctl-estimate"); 404 if (needed == 0) 405 return; 406 if ((buf = malloc(needed)) == NULL) 407 err(1, "malloc"); 408 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 409 err(1, "actual retrieval of routing table"); 410 lim = buf + needed; 411 for (next = buf; next < lim; next += rtm->rtm_msglen) { 412 rtm = (struct rt_msghdr *)next; 413 sina = (struct sockaddr_inarp *)(rtm + 1); 414 sdl = (struct sockaddr_dl *) 415 (ROUNDUP(sina->sin_len) + (char *)sina); 416 if (addr) { 417 if (addr != sina->sin_addr.s_addr) 418 continue; 419 found_entry = 1; 420 } 421 if (nflag == 0) 422 hp = gethostbyaddr((caddr_t)&(sina->sin_addr), 423 sizeof sina->sin_addr, AF_INET); 424 else 425 hp = NULL; 426 427 host = hp ? hp->h_name : "?"; 428 429 (void)printf("%s (%s) at ", host, inet_ntoa(sina->sin_addr)); 430 if (sdl->sdl_alen) 431 sdl_print(sdl); 432 else 433 (void)printf("(incomplete)"); 434 435 if (sdl->sdl_index) { 436 if (getifname(sdl->sdl_index, ifname, sizeof(ifname)) == 0) 437 printf(" on %s", ifname); 438 } 439 440 if (rtm->rtm_rmx.rmx_expire == 0) 441 (void)printf(" permanent"); 442 if (sina->sin_other & SIN_PROXY) 443 (void)printf(" published (proxy only)"); 444 if (rtm->rtm_addrs & RTA_NETMASK) { 445 sina = (struct sockaddr_inarp *) 446 (ROUNDUP(sdl->sdl_len) + (char *)sdl); 447 if (sina->sin_addr.s_addr == 0xffffffff) 448 (void)printf(" published"); 449 if (sina->sin_len != 8) 450 (void)printf("(weird)"); 451 } 452 (void)printf("\n"); 453 } 454 free(buf); 455 } 456 457 /* 458 * Delete the entire arp table 459 */ 460 void 461 delete_all(void) 462 { 463 int mib[6]; 464 size_t needed; 465 char addr[sizeof("000.000.000.000\0")]; 466 char *lim, *buf, *next; 467 struct rt_msghdr *rtm; 468 struct sockaddr_inarp *sina; 469 struct sockaddr_dl *sdl; 470 471 mib[0] = CTL_NET; 472 mib[1] = PF_ROUTE; 473 mib[2] = 0; 474 mib[3] = AF_INET; 475 mib[4] = NET_RT_FLAGS; 476 mib[5] = RTF_LLINFO; 477 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 478 err(1, "route-sysctl-estimate"); 479 if (needed == 0) 480 return; 481 if ((buf = malloc(needed)) == NULL) 482 err(1, "malloc"); 483 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 484 err(1, "actual retrieval of routing table"); 485 lim = buf + needed; 486 for (next = buf; next < lim; next += rtm->rtm_msglen) { 487 rtm = (struct rt_msghdr *)next; 488 sina = (struct sockaddr_inarp *)(rtm + 1); 489 sdl = (struct sockaddr_dl *) 490 (ROUNDUP(sina->sin_len) + (char *)sina); 491 snprintf(addr, sizeof(addr), "%s", inet_ntoa(sina->sin_addr)); 492 delete(addr, NULL); 493 } 494 free(buf); 495 } 496 497 void 498 sdl_print(const struct sockaddr_dl *sdl) 499 { 500 char hbuf[NI_MAXHOST]; 501 502 if (getnameinfo((const struct sockaddr *)sdl, sdl->sdl_len, 503 hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) 504 printf("<invalid>"); 505 else 506 printf("%s", hbuf); 507 } 508 509 int 510 atosdl(const char *ss, struct sockaddr_dl *sdl) 511 { 512 int i; 513 long b; 514 caddr_t endp; 515 caddr_t p; 516 char *t, *r; 517 518 p = LLADDR(sdl); 519 endp = ((caddr_t)sdl) + sdl->sdl_len; 520 i = 0; 521 522 b = strtol(ss, &t, 16); 523 if (t == ss) 524 return 1; 525 526 *p++ = b; 527 ++i; 528 while ((p < endp) && (*t++ == ':')) { 529 b = strtol(t, &r, 16); 530 if (r == t) 531 break; 532 *p++ = b; 533 ++i; 534 t = r; 535 } 536 sdl->sdl_alen = i; 537 538 return 0; 539 } 540 541 void 542 usage(void) 543 { 544 const char *progname; 545 546 progname = getprogname(); 547 (void)fprintf(stderr, "usage: %s [-n] hostname\n", progname); 548 (void)fprintf(stderr, "usage: %s [-nv] -a\n", progname); 549 (void)fprintf(stderr, "usage: %s [-v] -d [-a|hostname]\n", progname); 550 (void)fprintf(stderr, 551 "usage: %s -s hostname ether_addr [temp] [pub]\n", progname); 552 (void)fprintf(stderr, "usage: %s -f filename\n", progname); 553 exit(1); 554 } 555 556 int 557 rtmsg(int cmd) 558 { 559 static int seq; 560 int rlen; 561 struct rt_msghdr *rtm; 562 char *cp; 563 int l; 564 565 rtm = &m_rtmsg.m_rtm; 566 cp = m_rtmsg.m_space; 567 errno = 0; 568 569 if (cmd == RTM_DELETE) 570 goto doit; 571 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 572 rtm->rtm_flags = flags; 573 rtm->rtm_version = RTM_VERSION; 574 575 switch (cmd) { 576 default: 577 errx(1, "internal wrong cmd"); 578 /*NOTREACHED*/ 579 case RTM_ADD: 580 rtm->rtm_addrs |= RTA_GATEWAY; 581 rtm->rtm_rmx.rmx_expire = expire_time; 582 rtm->rtm_inits = RTV_EXPIRE; 583 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 584 sin_m.sin_other = 0; 585 if (doing_proxy) { 586 if (export_only) 587 sin_m.sin_other = SIN_PROXY; 588 else { 589 rtm->rtm_addrs |= RTA_NETMASK; 590 rtm->rtm_flags &= ~RTF_HOST; 591 } 592 } 593 /* FALLTHROUGH */ 594 case RTM_GET: 595 rtm->rtm_addrs |= RTA_DST; 596 } 597 598 #define NEXTADDR(w, s) \ 599 if (rtm->rtm_addrs & (w)) { \ 600 (void)memcpy(cp, &s, ((struct sockaddr *)&s)->sa_len); \ 601 cp += ROUNDUP(((struct sockaddr *)&s)->sa_len); \ 602 } 603 604 NEXTADDR(RTA_DST, sin_m); 605 NEXTADDR(RTA_GATEWAY, sdl_m); 606 NEXTADDR(RTA_NETMASK, so_mask); 607 608 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 609 doit: 610 l = rtm->rtm_msglen; 611 rtm->rtm_seq = ++seq; 612 rtm->rtm_type = cmd; 613 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 614 if (errno != ESRCH || cmd != RTM_DELETE) { 615 warn("writing to routing socket"); 616 return (-1); 617 } 618 } 619 do { 620 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 621 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 622 if (l < 0) 623 warn("read from routing socket"); 624 return (0); 625 } 626 627 int 628 getinetaddr(const char *host, struct in_addr *inap) 629 { 630 struct hostent *hp; 631 632 if (inet_aton(host, inap) == 1) 633 return (0); 634 if ((hp = gethostbyname(host)) == NULL) { 635 warnx("%s: %s", host, hstrerror(h_errno)); 636 return (-1); 637 } 638 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 639 return (0); 640 } 641 642 int 643 getifname(u_int16_t ifindex, char *ifname, size_t l) 644 { 645 int i; 646 struct ifaddrs *addr; 647 const struct sockaddr_dl *sdl = NULL; 648 649 if (ifaddrs == NULL) { 650 i = getifaddrs(&ifaddrs); 651 if (i != 0) 652 err(1, "getifaddrs"); 653 } 654 655 for (addr = ifaddrs; addr; addr = addr->ifa_next) { 656 if (addr->ifa_addr == NULL || 657 addr->ifa_addr->sa_family != AF_LINK) 658 continue; 659 660 sdl = (const struct sockaddr_dl *) addr->ifa_addr; 661 if (sdl && sdl->sdl_index == ifindex) { 662 (void) strlcpy(ifname, addr->ifa_name, l); 663 return 0; 664 } 665 } 666 667 return -1; 668 } 669
Indexes created Tue Sep 30 20:09:53 GMT 2025