arp.c revision 1.23
1 /* $NetBSD: arp.c,v 1.23 1998/02/10 03:45:06 mrg 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 1998/02/10 03:45:06 mrg 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 62 #include <net/if.h> 63 #include <net/if_dl.h> 64 #include <net/if_ether.h> 65 #include <net/if_types.h> 66 #include <net/route.h> 67 #include <netinet/in.h> 68 #include <netinet/if_inarp.h> 69 #include <arpa/inet.h> 70 71 #include <err.h> 72 #include <errno.h> 73 #include <netdb.h> 74 #include <nlist.h> 75 #include <paths.h> 76 #include <stdio.h> 77 #include <stdlib.h> 78 #include <string.h> 79 #include <unistd.h> 80 81 int delete __P((const char *, const char *)); 82 void dump __P((u_long)); 83 void sdl_print __P((const struct sockaddr_dl *)); 84 int atosdl __P((const char *s, struct sockaddr_dl *sdl)); 85 int file __P((char *)); 86 void get __P((const char *)); 87 int getinetaddr __P((const char *, struct in_addr *)); 88 void getsocket __P((void)); 89 int main __P((int, char **)); 90 int rtmsg __P((int)); 91 int set __P((int, char **)); 92 void usage __P((void)); 93 94 static int pid; 95 static int nflag, vflag; 96 static int s = -1; 97 98 int delete __P((const char *, const char *)); 99 void dump __P((u_long)); 100 void ether_print __P((const u_char *)); 101 int file __P((char *)); 102 void get __P((const char *)); 103 int getinetaddr __P((const char *, struct in_addr *)); 104 void getsocket __P((void)); 105 int rtmsg __P((int)); 106 int set __P((int, char **)); 107 void usage __P((void)); 108 109 int 110 main(argc, argv) 111 int argc; 112 char **argv; 113 { 114 int ch; 115 int op = 0; 116 117 pid = getpid(); 118 119 while ((ch = getopt(argc, argv, "andsfv")) != -1) 120 switch((char)ch) { 121 case 'a': 122 case 'd': 123 case 's': 124 case 'f': 125 if (op) 126 usage(); 127 op = ch; 128 break; 129 case 'n': 130 nflag = 1; 131 break; 132 case 'v': 133 vflag = 1; 134 break; 135 default: 136 usage(); 137 } 138 argc -= optind; 139 argv += optind; 140 141 switch((char)op) { 142 case 'a': 143 dump(0); 144 break; 145 case 'd': 146 if (argc < 1 || argc > 2) 147 usage(); 148 (void)delete(argv[0], argv[1]); 149 break; 150 case 's': 151 if (argc < 2 || argc > 5) 152 usage(); 153 return (set(argc, argv) ? 1 : 0); 154 case 'f': 155 if (argc != 1) 156 usage(); 157 return (file(argv[0])); 158 default: 159 if (argc != 1) 160 usage(); 161 get(argv[0]); 162 break; 163 } 164 return (0); 165 } 166 167 /* 168 * Process a file to set standard arp entries 169 */ 170 int 171 file(name) 172 char *name; 173 { 174 char line[100], arg[5][50], *args[5]; 175 int i, retval; 176 FILE *fp; 177 178 if ((fp = fopen(name, "r")) == NULL) 179 err(1, "cannot open %s", name); 180 args[0] = &arg[0][0]; 181 args[1] = &arg[1][0]; 182 args[2] = &arg[2][0]; 183 args[3] = &arg[3][0]; 184 args[4] = &arg[4][0]; 185 retval = 0; 186 while (fgets(line, 100, fp) != NULL) { 187 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 188 arg[3], arg[4]); 189 if (i < 2) { 190 warnx("bad line: %s", line); 191 retval = 1; 192 continue; 193 } 194 if (set(i, args)) 195 retval = 1; 196 } 197 fclose(fp); 198 return (retval); 199 } 200 201 void 202 getsocket() 203 { 204 if (s >= 0) 205 return; 206 s = socket(PF_ROUTE, SOCK_RAW, 0); 207 if (s < 0) 208 err(1, "socket"); 209 } 210 211 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 212 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 213 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 214 int expire_time, flags, export_only, doing_proxy, found_entry; 215 struct { 216 struct rt_msghdr m_rtm; 217 char m_space[512]; 218 } m_rtmsg; 219 220 /* 221 * Set an individual arp entry 222 */ 223 int 224 set(argc, argv) 225 int argc; 226 char **argv; 227 { 228 struct sockaddr_inarp *sin; 229 struct sockaddr_dl *sdl; 230 struct rt_msghdr *rtm; 231 char *host = argv[0], *eaddr; 232 int rval; 233 234 sin = &sin_m; 235 rtm = &(m_rtmsg.m_rtm); 236 eaddr = argv[1]; 237 238 getsocket(); 239 argc -= 2; 240 argv += 2; 241 sdl_m = blank_sdl; /* struct copy */ 242 sin_m = blank_sin; /* struct copy */ 243 if (getinetaddr(host, &sin->sin_addr) == -1) 244 return (1); 245 if (atosdl(eaddr, &sdl_m)) 246 warnx("invalid link-level address '%s'", eaddr); 247 doing_proxy = flags = export_only = expire_time = 0; 248 while (argc-- > 0) { 249 if (strncmp(argv[0], "temp", 4) == 0) { 250 struct timeval time; 251 (void)gettimeofday(&time, 0); 252 expire_time = time.tv_sec + 20 * 60; 253 } 254 else if (strncmp(argv[0], "pub", 3) == 0) { 255 flags |= RTF_ANNOUNCE; 256 doing_proxy = SIN_PROXY; 257 } else if (strncmp(argv[0], "trail", 5) == 0) { 258 (void)printf( 259 "%s: Sending trailers is no longer supported\n", 260 host); 261 } 262 argv++; 263 } 264 tryagain: 265 if (rtmsg(RTM_GET) < 0) { 266 warn("%s", host); 267 return (1); 268 } 269 sin = (struct sockaddr_inarp *)(rtm + 1); 270 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 271 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 272 if (sdl->sdl_family == AF_LINK && 273 (rtm->rtm_flags & RTF_LLINFO) && 274 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 275 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 276 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 277 goto overwrite; 278 } 279 if (doing_proxy == 0) { 280 (void)printf("set: can only proxy for %s\n", host); 281 return (1); 282 } 283 if (sin_m.sin_other & SIN_PROXY) { 284 (void)printf( 285 "set: proxy entry exists for non 802 device\n"); 286 return (1); 287 } 288 sin_m.sin_other = SIN_PROXY; 289 export_only = 1; 290 goto tryagain; 291 } 292 overwrite: 293 if (sdl->sdl_family != AF_LINK) { 294 (void)printf("cannot intuit interface index and type for %s\n", 295 host); 296 return (1); 297 } 298 sdl_m.sdl_type = sdl->sdl_type; 299 sdl_m.sdl_index = sdl->sdl_index; 300 rval = rtmsg(RTM_ADD); 301 if (vflag) 302 (void)printf("%s (%s) added\n", host, eaddr); 303 return (rval); 304 } 305 306 /* 307 * Display an individual arp entry 308 */ 309 void 310 get(host) 311 const char *host; 312 { 313 struct sockaddr_inarp *sin; 314 315 sin = &sin_m; 316 sin_m = blank_sin; /* struct copy */ 317 if (getinetaddr(host, &sin->sin_addr) == -1) 318 exit(1); 319 dump(sin->sin_addr.s_addr); 320 if (found_entry == 0) { 321 (void)printf("%s (%s) -- no entry\n", host, 322 inet_ntoa(sin->sin_addr)); 323 exit(1); 324 } 325 } 326 327 /* 328 * Delete an arp entry 329 */ 330 int 331 delete(host, info) 332 const char *host; 333 const char *info; 334 { 335 struct sockaddr_inarp *sin; 336 struct rt_msghdr *rtm; 337 struct sockaddr_dl *sdl; 338 339 sin = &sin_m; 340 rtm = &m_rtmsg.m_rtm; 341 342 if (info && strncmp(info, "pro", 3) ) 343 export_only = 1; 344 getsocket(); 345 sin_m = blank_sin; /* struct copy */ 346 if (getinetaddr(host, &sin->sin_addr) == -1) 347 return (1); 348 tryagain: 349 if (rtmsg(RTM_GET) < 0) { 350 warn("%s", host); 351 return (1); 352 } 353 sin = (struct sockaddr_inarp *)(rtm + 1); 354 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 355 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 356 if (sdl->sdl_family == AF_LINK && 357 (rtm->rtm_flags & RTF_LLINFO) && 358 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 359 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 360 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 361 goto delete; 362 } 363 } 364 if (sin_m.sin_other & SIN_PROXY) { 365 warnx("delete: can't locate %s", host); 366 return (1); 367 } else { 368 sin_m.sin_other = SIN_PROXY; 369 goto tryagain; 370 } 371 delete: 372 if (sdl->sdl_family != AF_LINK) { 373 (void)printf("cannot locate %s\n", host); 374 return (1); 375 } 376 if (rtmsg(RTM_DELETE)) 377 return (1); 378 if (vflag) 379 (void)printf("%s (%s) deleted\n", host, 380 inet_ntoa(sin->sin_addr)); 381 return (0); 382 } 383 384 /* 385 * Dump the entire arp table 386 */ 387 void 388 dump(addr) 389 u_long addr; 390 { 391 int mib[6]; 392 size_t needed; 393 char *host, *lim, *buf, *next; 394 struct rt_msghdr *rtm; 395 struct sockaddr_inarp *sin; 396 struct sockaddr_dl *sdl; 397 extern int h_errno; 398 struct hostent *hp; 399 400 mib[0] = CTL_NET; 401 mib[1] = PF_ROUTE; 402 mib[2] = 0; 403 mib[3] = AF_INET; 404 mib[4] = NET_RT_FLAGS; 405 mib[5] = RTF_LLINFO; 406 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 407 err(1, "route-sysctl-estimate"); 408 if (needed == 0) 409 return; 410 if ((buf = malloc(needed)) == NULL) 411 err(1, "malloc"); 412 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 413 err(1, "actual retrieval of routing table"); 414 lim = buf + needed; 415 for (next = buf; next < lim; next += rtm->rtm_msglen) { 416 rtm = (struct rt_msghdr *)next; 417 sin = (struct sockaddr_inarp *)(rtm + 1); 418 sdl = (struct sockaddr_dl *)(sin + 1); 419 if (addr) { 420 if (addr != sin->sin_addr.s_addr) 421 continue; 422 found_entry = 1; 423 } 424 if (nflag == 0) 425 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 426 sizeof sin->sin_addr, AF_INET); 427 else 428 hp = 0; 429 if (hp) 430 host = hp->h_name; 431 else { 432 host = "?"; 433 if (h_errno == TRY_AGAIN) 434 nflag = 1; 435 } 436 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 437 if (sdl->sdl_alen) 438 sdl_print(sdl); 439 else 440 (void)printf("(incomplete)"); 441 if (rtm->rtm_rmx.rmx_expire == 0) 442 (void)printf(" permanent"); 443 if (sin->sin_other & SIN_PROXY) 444 (void)printf(" published (proxy only)"); 445 if (rtm->rtm_addrs & RTA_NETMASK) { 446 sin = (struct sockaddr_inarp *) 447 (sdl->sdl_len + (char *)sdl); 448 if (sin->sin_addr.s_addr == 0xffffffff) 449 (void)printf(" published"); 450 if (sin->sin_len != 8) 451 (void)printf("(wierd)"); 452 } 453 (void)printf("\n"); 454 } 455 } 456 457 void 458 sdl_print(sdl) 459 const struct sockaddr_dl *sdl; 460 { 461 int i; 462 u_int8_t *p; 463 const char *hexfmt = "%x"; 464 465 if (sdl->sdl_type == IFT_ETHER || sdl->sdl_type == IFT_FDDI) 466 hexfmt = "%02x"; 467 468 i = sdl->sdl_alen; 469 p = LLADDR(sdl); 470 471 (void)printf(hexfmt, *p); 472 while (--i > 0) { 473 putchar(':'); 474 (void)printf(hexfmt, *++p); 475 } 476 } 477 478 int 479 atosdl(s, sdl) 480 const char *s; 481 struct sockaddr_dl *sdl; 482 { 483 int i; 484 long b; 485 caddr_t endp; 486 caddr_t p; 487 char *t, *r; 488 489 p = LLADDR(sdl); 490 endp = ((caddr_t)sdl) + sdl->sdl_len; 491 i = 0; 492 493 b = strtol(s, &t, 16); 494 if (t == s) 495 return 1; 496 497 *p++ = b; 498 ++i; 499 while ((p < endp) && (*t++ == ':')) { 500 b = strtol(t, &r, 16); 501 if (r == t) 502 break; 503 *p++ = b; 504 ++i; 505 t = r; 506 } 507 sdl->sdl_alen = i; 508 509 return 0; 510 } 511 512 void 513 usage() 514 { 515 extern char *__progname; 516 517 (void)fprintf(stderr, "usage: %s [-n] hostname\n", __progname); 518 (void)fprintf(stderr, "usage: %s [-n] -a\n", __progname); 519 (void)fprintf(stderr, "usage: %s -d hostname\n", __progname); 520 (void)fprintf(stderr, 521 "usage: %s -s hostname ether_addr [temp] [pub]\n", __progname); 522 (void)fprintf(stderr, "usage: %s -f filename\n", __progname); 523 exit(1); 524 } 525 526 int 527 rtmsg(cmd) 528 int cmd; 529 { 530 static int seq; 531 int rlen; 532 struct rt_msghdr *rtm; 533 char *cp; 534 int l; 535 536 rtm = &m_rtmsg.m_rtm; 537 cp = m_rtmsg.m_space; 538 errno = 0; 539 540 if (cmd == RTM_DELETE) 541 goto doit; 542 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 543 rtm->rtm_flags = flags; 544 rtm->rtm_version = RTM_VERSION; 545 546 switch (cmd) { 547 default: 548 errx(1, "internal wrong cmd"); 549 /*NOTREACHED*/ 550 case RTM_ADD: 551 rtm->rtm_addrs |= RTA_GATEWAY; 552 rtm->rtm_rmx.rmx_expire = expire_time; 553 rtm->rtm_inits = RTV_EXPIRE; 554 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 555 sin_m.sin_other = 0; 556 if (doing_proxy) { 557 if (export_only) 558 sin_m.sin_other = SIN_PROXY; 559 else { 560 rtm->rtm_addrs |= RTA_NETMASK; 561 rtm->rtm_flags &= ~RTF_HOST; 562 } 563 } 564 /* FALLTHROUGH */ 565 case RTM_GET: 566 rtm->rtm_addrs |= RTA_DST; 567 } 568 #define NEXTADDR(w, s) \ 569 if (rtm->rtm_addrs & (w)) { \ 570 (void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);} 571 572 NEXTADDR(RTA_DST, sin_m); 573 NEXTADDR(RTA_GATEWAY, sdl_m); 574 NEXTADDR(RTA_NETMASK, so_mask); 575 576 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 577 doit: 578 l = rtm->rtm_msglen; 579 rtm->rtm_seq = ++seq; 580 rtm->rtm_type = cmd; 581 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 582 if (errno != ESRCH || cmd != RTM_DELETE) { 583 warn("writing to routing socket"); 584 return (-1); 585 } 586 } 587 do { 588 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 589 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 590 if (l < 0) 591 warn("read from routing socket"); 592 return (0); 593 } 594 595 int 596 getinetaddr(host, inap) 597 const char *host; 598 struct in_addr *inap; 599 { 600 struct hostent *hp; 601 602 if (inet_aton(host, inap) == 1) 603 return (0); 604 if ((hp = gethostbyname(host)) == NULL) { 605 warnx("%s: %s\n", host, hstrerror(h_errno)); 606 return (-1); 607 } 608 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 609 return (0); 610 } 611
Indexes created Tue Sep 30 20:09:53 GMT 2025