arp.c revision 1.23.2.2
1 /* $NetBSD: arp.c,v 1.23.2.2 2001/04/01 15:01:19 he 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 1.23.2.2 2001/04/01 15:01:19 he Exp $"); 50 #endif 51 #endif /* not lint */ 52 53 /* 54 * arp - display, set, and delete arp table entries 55 */ 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 82 int delete __P((const char *, const char *)); 83 void dump __P((u_long)); 84 void sdl_print __P((const struct sockaddr_dl *)); 85 int getifname __P((u_int16_t, char *)); 86 int atosdl __P((const char *s, struct sockaddr_dl *sdl)); 87 int file __P((char *)); 88 void get __P((const char *)); 89 int getinetaddr __P((const char *, struct in_addr *)); 90 void getsocket __P((void)); 91 int main __P((int, char **)); 92 int rtmsg __P((int)); 93 int set __P((int, char **)); 94 void usage __P((void)); 95 96 static int pid; 97 static int nflag, vflag; 98 static int s = -1; 99 static int is = -1; 100 101 static struct ifconf ifc; 102 static char ifconfbuf[8192]; 103 static char *progname; 104 105 int delete __P((const char *, const char *)); 106 void dump __P((u_long)); 107 void ether_print __P((const u_char *)); 108 int file __P((char *)); 109 void get __P((const char *)); 110 int getinetaddr __P((const char *, struct in_addr *)); 111 void getsocket __P((void)); 112 int rtmsg __P((int)); 113 int set __P((int, char **)); 114 void usage __P((void)); 115 116 int 117 main(argc, argv) 118 int argc; 119 char **argv; 120 { 121 int ch; 122 int op = 0; 123 124 pid = getpid(); 125 progname = ((progname = strrchr(argv[0], '/')) ? progname + 1 : argv[0]); 126 127 while ((ch = getopt(argc, argv, "andsfv")) != -1) 128 switch((char)ch) { 129 case 'a': 130 case 'd': 131 case 's': 132 case 'f': 133 if (op) 134 usage(); 135 op = ch; 136 break; 137 case 'n': 138 nflag = 1; 139 break; 140 case 'v': 141 vflag = 1; 142 break; 143 default: 144 usage(); 145 } 146 argc -= optind; 147 argv += optind; 148 149 switch((char)op) { 150 case 'a': 151 dump(0); 152 break; 153 case 'd': 154 if (argc < 1 || argc > 2) 155 usage(); 156 (void)delete(argv[0], argv[1]); 157 break; 158 case 's': 159 if (argc < 2 || argc > 5) 160 usage(); 161 return (set(argc, argv) ? 1 : 0); 162 case 'f': 163 if (argc != 1) 164 usage(); 165 return (file(argv[0])); 166 default: 167 if (argc != 1) 168 usage(); 169 get(argv[0]); 170 break; 171 } 172 return (0); 173 } 174 175 /* 176 * Process a file to set standard arp entries 177 */ 178 int 179 file(name) 180 char *name; 181 { 182 char line[100], arg[5][50], *args[5]; 183 int i, retval; 184 FILE *fp; 185 186 if ((fp = fopen(name, "r")) == NULL) 187 err(1, "cannot open %s", name); 188 args[0] = &arg[0][0]; 189 args[1] = &arg[1][0]; 190 args[2] = &arg[2][0]; 191 args[3] = &arg[3][0]; 192 args[4] = &arg[4][0]; 193 retval = 0; 194 while (fgets(line, 100, fp) != NULL) { 195 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 196 arg[3], arg[4]); 197 if (i < 2) { 198 warnx("bad line: %s", line); 199 retval = 1; 200 continue; 201 } 202 if (set(i, args)) 203 retval = 1; 204 } 205 fclose(fp); 206 return (retval); 207 } 208 209 void 210 getsocket() 211 { 212 if (s >= 0) 213 return; 214 s = socket(PF_ROUTE, SOCK_RAW, 0); 215 if (s < 0) 216 err(1, "socket"); 217 } 218 219 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 220 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 221 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 222 int expire_time, flags, export_only, doing_proxy, found_entry; 223 struct { 224 struct rt_msghdr m_rtm; 225 char m_space[512]; 226 } m_rtmsg; 227 228 /* 229 * Set an individual arp entry 230 */ 231 int 232 set(argc, argv) 233 int argc; 234 char **argv; 235 { 236 struct sockaddr_inarp *sin; 237 struct sockaddr_dl *sdl; 238 struct rt_msghdr *rtm; 239 char *host = argv[0], *eaddr; 240 int rval; 241 242 sin = &sin_m; 243 rtm = &(m_rtmsg.m_rtm); 244 eaddr = argv[1]; 245 246 getsocket(); 247 argc -= 2; 248 argv += 2; 249 sdl_m = blank_sdl; /* struct copy */ 250 sin_m = blank_sin; /* struct copy */ 251 if (getinetaddr(host, &sin->sin_addr) == -1) 252 return (1); 253 if (atosdl(eaddr, &sdl_m)) 254 warnx("invalid link-level address '%s'", eaddr); 255 doing_proxy = flags = export_only = expire_time = 0; 256 while (argc-- > 0) { 257 if (strncmp(argv[0], "temp", 4) == 0) { 258 struct timeval time; 259 (void)gettimeofday(&time, 0); 260 expire_time = time.tv_sec + 20 * 60; 261 } 262 else if (strncmp(argv[0], "pub", 3) == 0) { 263 flags |= RTF_ANNOUNCE; 264 doing_proxy = SIN_PROXY; 265 } else if (strncmp(argv[0], "trail", 5) == 0) { 266 (void)printf( 267 "%s: Sending trailers is no longer supported\n", 268 host); 269 } 270 argv++; 271 } 272 tryagain: 273 if (rtmsg(RTM_GET) < 0) { 274 warn("%s", host); 275 return (1); 276 } 277 sin = (struct sockaddr_inarp *)(rtm + 1); 278 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 279 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 280 if (sdl->sdl_family == AF_LINK && 281 (rtm->rtm_flags & RTF_LLINFO) && 282 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 283 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 284 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 285 goto overwrite; 286 } 287 if (doing_proxy == 0) { 288 (void)printf("set: can only proxy for %s\n", host); 289 return (1); 290 } 291 if (sin_m.sin_other & SIN_PROXY) { 292 (void)printf( 293 "set: proxy entry exists for non 802 device\n"); 294 return (1); 295 } 296 sin_m.sin_other = SIN_PROXY; 297 export_only = 1; 298 goto tryagain; 299 } 300 overwrite: 301 if (sdl->sdl_family != AF_LINK) { 302 (void)printf("cannot intuit interface index and type for %s\n", 303 host); 304 return (1); 305 } 306 sdl_m.sdl_type = sdl->sdl_type; 307 sdl_m.sdl_index = sdl->sdl_index; 308 rval = rtmsg(RTM_ADD); 309 if (vflag) 310 (void)printf("%s (%s) added\n", host, eaddr); 311 return (rval); 312 } 313 314 /* 315 * Display an individual arp entry 316 */ 317 void 318 get(host) 319 const char *host; 320 { 321 struct sockaddr_inarp *sin; 322 323 sin = &sin_m; 324 sin_m = blank_sin; /* struct copy */ 325 if (getinetaddr(host, &sin->sin_addr) == -1) 326 exit(1); 327 dump(sin->sin_addr.s_addr); 328 if (found_entry == 0) { 329 (void)printf("%s (%s) -- no entry\n", host, 330 inet_ntoa(sin->sin_addr)); 331 exit(1); 332 } 333 } 334 335 /* 336 * Delete an arp entry 337 */ 338 int 339 delete(host, info) 340 const char *host; 341 const char *info; 342 { 343 struct sockaddr_inarp *sin; 344 struct rt_msghdr *rtm; 345 struct sockaddr_dl *sdl; 346 347 sin = &sin_m; 348 rtm = &m_rtmsg.m_rtm; 349 350 if (info && strncmp(info, "pro", 3) ) 351 export_only = 1; 352 getsocket(); 353 sin_m = blank_sin; /* struct copy */ 354 if (getinetaddr(host, &sin->sin_addr) == -1) 355 return (1); 356 tryagain: 357 if (rtmsg(RTM_GET) < 0) { 358 warn("%s", host); 359 return (1); 360 } 361 sin = (struct sockaddr_inarp *)(rtm + 1); 362 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 363 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 364 if (sdl->sdl_family == AF_LINK && 365 (rtm->rtm_flags & RTF_LLINFO) && 366 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 367 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 368 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 369 goto delete; 370 } 371 } 372 if (sin_m.sin_other & SIN_PROXY) { 373 warnx("delete: can't locate %s", host); 374 return (1); 375 } else { 376 sin_m.sin_other = SIN_PROXY; 377 goto tryagain; 378 } 379 delete: 380 if (sdl->sdl_family != AF_LINK) { 381 (void)printf("cannot locate %s\n", host); 382 return (1); 383 } 384 if (rtmsg(RTM_DELETE)) 385 return (1); 386 if (vflag) 387 (void)printf("%s (%s) deleted\n", host, 388 inet_ntoa(sin->sin_addr)); 389 return (0); 390 } 391 392 /* 393 * Dump the entire arp table 394 */ 395 void 396 dump(addr) 397 u_long addr; 398 { 399 int mib[6]; 400 size_t needed; 401 char ifname[IFNAMSIZ]; 402 char *host, *lim, *buf, *next; 403 struct rt_msghdr *rtm; 404 struct sockaddr_inarp *sin; 405 struct sockaddr_dl *sdl; 406 extern int h_errno; 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 *)(sin + 1); 428 if (addr) { 429 if (addr != sin->sin_addr.s_addr) 430 continue; 431 found_entry = 1; 432 } 433 if (nflag == 0) 434 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 435 sizeof sin->sin_addr, AF_INET); 436 else 437 hp = 0; 438 if (hp) 439 host = hp->h_name; 440 else { 441 host = "?"; 442 if (h_errno == TRY_AGAIN) 443 nflag = 1; 444 } 445 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 446 if (sdl->sdl_alen) 447 sdl_print(sdl); 448 else 449 (void)printf("(incomplete)"); 450 451 if (sdl->sdl_index) { 452 if (getifname(sdl->sdl_index, ifname) == 0) 453 printf(" on %s", ifname); 454 } 455 456 if (rtm->rtm_rmx.rmx_expire == 0) 457 (void)printf(" permanent"); 458 if (sin->sin_other & SIN_PROXY) 459 (void)printf(" published (proxy only)"); 460 if (rtm->rtm_addrs & RTA_NETMASK) { 461 sin = (struct sockaddr_inarp *) 462 (sdl->sdl_len + (char *)sdl); 463 if (sin->sin_addr.s_addr == 0xffffffff) 464 (void)printf(" published"); 465 if (sin->sin_len != 8) 466 (void)printf("(wierd)"); 467 } 468 (void)printf("\n"); 469 } 470 } 471 472 void 473 sdl_print(sdl) 474 const struct sockaddr_dl *sdl; 475 { 476 int i; 477 u_int8_t *p; 478 479 i = sdl->sdl_alen; 480 p = LLADDR(sdl); 481 482 (void)printf("%02x", *p); 483 while (--i > 0) { 484 putchar(':'); 485 (void)printf("%02x", *++p); 486 } 487 } 488 489 int 490 atosdl(s, sdl) 491 const char *s; 492 struct sockaddr_dl *sdl; 493 { 494 int i; 495 long b; 496 caddr_t endp; 497 caddr_t p; 498 char *t, *r; 499 500 p = LLADDR(sdl); 501 endp = ((caddr_t)sdl) + sdl->sdl_len; 502 i = 0; 503 504 b = strtol(s, &t, 16); 505 if (t == s) 506 return 1; 507 508 *p++ = b; 509 ++i; 510 while ((p < endp) && (*t++ == ':')) { 511 b = strtol(t, &r, 16); 512 if (r == t) 513 break; 514 *p++ = b; 515 ++i; 516 t = r; 517 } 518 sdl->sdl_alen = i; 519 520 return 0; 521 } 522 523 void 524 usage() 525 { 526 527 (void)fprintf(stderr, "usage: %s [-n] hostname\n", progname); 528 (void)fprintf(stderr, "usage: %s [-n] -a\n", progname); 529 (void)fprintf(stderr, "usage: %s -d hostname\n", progname); 530 (void)fprintf(stderr, 531 "usage: %s -s hostname ether_addr [temp] [pub]\n", progname); 532 (void)fprintf(stderr, "usage: %s -f filename\n", progname); 533 exit(1); 534 } 535 536 int 537 rtmsg(cmd) 538 int cmd; 539 { 540 static int seq; 541 int rlen; 542 struct rt_msghdr *rtm; 543 char *cp; 544 int l; 545 546 rtm = &m_rtmsg.m_rtm; 547 cp = m_rtmsg.m_space; 548 errno = 0; 549 550 if (cmd == RTM_DELETE) 551 goto doit; 552 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 553 rtm->rtm_flags = flags; 554 rtm->rtm_version = RTM_VERSION; 555 556 switch (cmd) { 557 default: 558 errx(1, "internal wrong cmd"); 559 /*NOTREACHED*/ 560 case RTM_ADD: 561 rtm->rtm_addrs |= RTA_GATEWAY; 562 rtm->rtm_rmx.rmx_expire = expire_time; 563 rtm->rtm_inits = RTV_EXPIRE; 564 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 565 sin_m.sin_other = 0; 566 if (doing_proxy) { 567 if (export_only) 568 sin_m.sin_other = SIN_PROXY; 569 else { 570 rtm->rtm_addrs |= RTA_NETMASK; 571 rtm->rtm_flags &= ~RTF_HOST; 572 } 573 } 574 /* FALLTHROUGH */ 575 case RTM_GET: 576 rtm->rtm_addrs |= RTA_DST; 577 } 578 #define NEXTADDR(w, s) \ 579 if (rtm->rtm_addrs & (w)) { \ 580 (void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);} 581 582 NEXTADDR(RTA_DST, sin_m); 583 NEXTADDR(RTA_GATEWAY, sdl_m); 584 NEXTADDR(RTA_NETMASK, so_mask); 585 586 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 587 doit: 588 l = rtm->rtm_msglen; 589 rtm->rtm_seq = ++seq; 590 rtm->rtm_type = cmd; 591 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 592 if (errno != ESRCH || cmd != RTM_DELETE) { 593 warn("writing to routing socket"); 594 return (-1); 595 } 596 } 597 do { 598 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 599 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 600 if (l < 0) 601 warn("read from routing socket"); 602 return (0); 603 } 604 605 int 606 getinetaddr(host, inap) 607 const char *host; 608 struct in_addr *inap; 609 { 610 struct hostent *hp; 611 612 if (inet_aton(host, inap) == 1) 613 return (0); 614 if ((hp = gethostbyname(host)) == NULL) { 615 warnx("%s: %s\n", host, hstrerror(h_errno)); 616 return (-1); 617 } 618 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 619 return (0); 620 } 621 622 int 623 getifname(ifindex, ifname) 624 u_int16_t ifindex; 625 char* ifname; 626 { 627 int i, idx, siz; 628 char ifrbuf[8192]; 629 struct ifreq ifreq, *ifr; 630 const struct sockaddr_dl *sdl = NULL; 631 632 if (is < 0) { 633 is = socket(PF_INET, SOCK_DGRAM, 0); 634 if (is < 0) 635 err(1, "socket"); 636 637 ifc.ifc_len = sizeof(ifconfbuf); 638 ifc.ifc_buf = ifconfbuf; 639 640 if (ioctl(is, SIOCGIFCONF, &ifc) < 0) { 641 close(is); 642 err(1, "SIOCGIFCONF"); 643 is = -1; 644 } 645 } 646 647 ifr = ifc.ifc_req; 648 ifreq.ifr_name[0] = '\0'; 649 for (i = 0, idx = 0; i < ifc.ifc_len; ) { 650 ifr = (struct ifreq *)((caddr_t)ifc.ifc_req + i); 651 siz = sizeof(ifr->ifr_name) + 652 (ifr->ifr_addr.sa_len > sizeof(struct sockaddr) 653 ? ifr->ifr_addr.sa_len 654 : sizeof(struct sockaddr)); 655 i += siz; 656 /* avoid alignment issue */ 657 if (sizeof(ifrbuf) < siz) 658 errx(1, "ifr too big"); 659 660 memcpy(ifrbuf, ifr, siz); 661 ifr = (struct ifreq *)ifrbuf; 662 663 if (ifr->ifr_addr.sa_family != AF_LINK) 664 continue; 665 666 sdl = (const struct sockaddr_dl *) &ifr->ifr_addr; 667 if (sdl && sdl->sdl_index == ifindex) { 668 (void) strncpy(ifname, ifr->ifr_name, IFNAMSIZ); 669 return 0; 670 } 671 } 672 673 return -1; 674 } 675
Indexes created Tue Sep 30 20:09:53 GMT 2025