arp.c revision 1.21
1 /* $NetBSD: arp.c,v 1.21 1997/11/16 11:25:08 is 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 1.21 1997/11/16 11:25:08 is 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; 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, "andsf")) != -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 default: 133 usage(); 134 } 135 argc -= optind; 136 argv += optind; 137 138 switch((char)op) { 139 case 'a': 140 dump(0); 141 break; 142 case 'd': 143 if (argc < 1 || argc > 2) 144 usage(); 145 (void)delete(argv[0], argv[1]); 146 break; 147 case 's': 148 if (argc < 2 || argc > 5) 149 usage(); 150 return (set(argc, argv) ? 1 : 0); 151 case 'f': 152 if (argc != 1) 153 usage(); 154 return (file(argv[0])); 155 default: 156 if (argc != 1) 157 usage(); 158 get(argv[0]); 159 break; 160 } 161 return (0); 162 } 163 164 /* 165 * Process a file to set standard arp entries 166 */ 167 int 168 file(name) 169 char *name; 170 { 171 char line[100], arg[5][50], *args[5]; 172 int i, retval; 173 FILE *fp; 174 175 if ((fp = fopen(name, "r")) == NULL) 176 err(1, "cannot open %s", name); 177 args[0] = &arg[0][0]; 178 args[1] = &arg[1][0]; 179 args[2] = &arg[2][0]; 180 args[3] = &arg[3][0]; 181 args[4] = &arg[4][0]; 182 retval = 0; 183 while (fgets(line, 100, fp) != NULL) { 184 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 185 arg[3], arg[4]); 186 if (i < 2) { 187 warnx("bad line: %s", line); 188 retval = 1; 189 continue; 190 } 191 if (set(i, args)) 192 retval = 1; 193 } 194 fclose(fp); 195 return (retval); 196 } 197 198 void 199 getsocket() 200 { 201 if (s >= 0) 202 return; 203 s = socket(PF_ROUTE, SOCK_RAW, 0); 204 if (s < 0) 205 err(1, "socket"); 206 } 207 208 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 209 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 210 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 211 int expire_time, flags, export_only, doing_proxy, found_entry; 212 struct { 213 struct rt_msghdr m_rtm; 214 char m_space[512]; 215 } m_rtmsg; 216 217 /* 218 * Set an individual arp entry 219 */ 220 int 221 set(argc, argv) 222 int argc; 223 char **argv; 224 { 225 struct sockaddr_inarp *sin; 226 struct sockaddr_dl *sdl; 227 struct rt_msghdr *rtm; 228 char *host = argv[0], *eaddr; 229 230 sin = &sin_m; 231 rtm = &(m_rtmsg.m_rtm); 232 eaddr = argv[1]; 233 234 getsocket(); 235 argc -= 2; 236 argv += 2; 237 sdl_m = blank_sdl; /* struct copy */ 238 sin_m = blank_sin; /* struct copy */ 239 if (getinetaddr(host, &sin->sin_addr) == -1) 240 return (1); 241 if (atosdl(eaddr, &sdl_m)) 242 warnx("invalid link-level address '%s'", eaddr); 243 doing_proxy = flags = export_only = expire_time = 0; 244 while (argc-- > 0) { 245 if (strncmp(argv[0], "temp", 4) == 0) { 246 struct timeval time; 247 (void)gettimeofday(&time, 0); 248 expire_time = time.tv_sec + 20 * 60; 249 } 250 else if (strncmp(argv[0], "pub", 3) == 0) { 251 flags |= RTF_ANNOUNCE; 252 doing_proxy = SIN_PROXY; 253 } else if (strncmp(argv[0], "trail", 5) == 0) { 254 (void)printf( 255 "%s: Sending trailers is no longer supported\n", 256 host); 257 } 258 argv++; 259 } 260 tryagain: 261 if (rtmsg(RTM_GET) < 0) { 262 warn("%s", host); 263 return (1); 264 } 265 sin = (struct sockaddr_inarp *)(rtm + 1); 266 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 267 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 268 if (sdl->sdl_family == AF_LINK && 269 (rtm->rtm_flags & RTF_LLINFO) && 270 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 271 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 272 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 273 goto overwrite; 274 } 275 if (doing_proxy == 0) { 276 (void)printf("set: can only proxy for %s\n", host); 277 return (1); 278 } 279 if (sin_m.sin_other & SIN_PROXY) { 280 (void)printf( 281 "set: proxy entry exists for non 802 device\n"); 282 return (1); 283 } 284 sin_m.sin_other = SIN_PROXY; 285 export_only = 1; 286 goto tryagain; 287 } 288 overwrite: 289 if (sdl->sdl_family != AF_LINK) { 290 (void)printf("cannot intuit interface index and type for %s\n", 291 host); 292 return (1); 293 } 294 sdl_m.sdl_type = sdl->sdl_type; 295 sdl_m.sdl_index = sdl->sdl_index; 296 return (rtmsg(RTM_ADD)); 297 } 298 299 /* 300 * Display an individual arp entry 301 */ 302 void 303 get(host) 304 const char *host; 305 { 306 struct sockaddr_inarp *sin; 307 308 sin = &sin_m; 309 sin_m = blank_sin; /* struct copy */ 310 if (getinetaddr(host, &sin->sin_addr) == -1) 311 exit(1); 312 dump(sin->sin_addr.s_addr); 313 if (found_entry == 0) { 314 (void)printf("%s (%s) -- no entry\n", host, 315 inet_ntoa(sin->sin_addr)); 316 exit(1); 317 } 318 } 319 320 /* 321 * Delete an arp entry 322 */ 323 int 324 delete(host, info) 325 const char *host; 326 const char *info; 327 { 328 struct sockaddr_inarp *sin; 329 struct rt_msghdr *rtm; 330 struct sockaddr_dl *sdl; 331 332 sin = &sin_m; 333 rtm = &m_rtmsg.m_rtm; 334 335 if (info && strncmp(info, "pro", 3) ) 336 export_only = 1; 337 getsocket(); 338 sin_m = blank_sin; /* struct copy */ 339 if (getinetaddr(host, &sin->sin_addr) == -1) 340 return (1); 341 tryagain: 342 if (rtmsg(RTM_GET) < 0) { 343 warn("%s", host); 344 return (1); 345 } 346 sin = (struct sockaddr_inarp *)(rtm + 1); 347 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 348 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 349 if (sdl->sdl_family == AF_LINK && 350 (rtm->rtm_flags & RTF_LLINFO) && 351 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 352 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 353 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 354 goto delete; 355 } 356 } 357 if (sin_m.sin_other & SIN_PROXY) { 358 warnx("delete: can't locate %s", host); 359 return (1); 360 } else { 361 sin_m.sin_other = SIN_PROXY; 362 goto tryagain; 363 } 364 delete: 365 if (sdl->sdl_family != AF_LINK) { 366 (void)printf("cannot locate %s\n", host); 367 return (1); 368 } 369 if (rtmsg(RTM_DELETE)) 370 return (1); 371 (void)printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 372 return (0); 373 } 374 375 /* 376 * Dump the entire arp table 377 */ 378 void 379 dump(addr) 380 u_long addr; 381 { 382 int mib[6]; 383 size_t needed; 384 char *host, *lim, *buf, *next; 385 struct rt_msghdr *rtm; 386 struct sockaddr_inarp *sin; 387 struct sockaddr_dl *sdl; 388 extern int h_errno; 389 struct hostent *hp; 390 391 mib[0] = CTL_NET; 392 mib[1] = PF_ROUTE; 393 mib[2] = 0; 394 mib[3] = AF_INET; 395 mib[4] = NET_RT_FLAGS; 396 mib[5] = RTF_LLINFO; 397 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 398 err(1, "route-sysctl-estimate"); 399 if ((buf = malloc(needed)) == NULL) 400 err(1, "malloc"); 401 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 402 err(1, "actual retrieval of routing table"); 403 lim = buf + needed; 404 for (next = buf; next < lim; next += rtm->rtm_msglen) { 405 rtm = (struct rt_msghdr *)next; 406 sin = (struct sockaddr_inarp *)(rtm + 1); 407 sdl = (struct sockaddr_dl *)(sin + 1); 408 if (addr) { 409 if (addr != sin->sin_addr.s_addr) 410 continue; 411 found_entry = 1; 412 } 413 if (nflag == 0) 414 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 415 sizeof sin->sin_addr, AF_INET); 416 else 417 hp = 0; 418 if (hp) 419 host = hp->h_name; 420 else { 421 host = "?"; 422 if (h_errno == TRY_AGAIN) 423 nflag = 1; 424 } 425 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 426 if (sdl->sdl_alen) 427 sdl_print(sdl); 428 else 429 (void)printf("(incomplete)"); 430 if (rtm->rtm_rmx.rmx_expire == 0) 431 (void)printf(" permanent"); 432 if (sin->sin_other & SIN_PROXY) 433 (void)printf(" published (proxy only)"); 434 if (rtm->rtm_addrs & RTA_NETMASK) { 435 sin = (struct sockaddr_inarp *) 436 (sdl->sdl_len + (char *)sdl); 437 if (sin->sin_addr.s_addr == 0xffffffff) 438 (void)printf(" published"); 439 if (sin->sin_len != 8) 440 (void)printf("(wierd)"); 441 } 442 (void)printf("\n"); 443 } 444 } 445 446 void 447 sdl_print(sdl) 448 const struct sockaddr_dl *sdl; 449 { 450 int i; 451 u_int8_t *p; 452 const char *hexfmt = "%x"; 453 454 if (sdl->sdl_type == IFT_ETHER || sdl->sdl_type == IFT_FDDI) 455 hexfmt = "%02x"; 456 457 i = sdl->sdl_alen; 458 p = LLADDR(sdl); 459 460 (void)printf(hexfmt, *p); 461 while (--i > 0) { 462 putchar(':'); 463 (void)printf(hexfmt, *++p); 464 } 465 } 466 467 int 468 atosdl(s, sdl) 469 const char *s; 470 struct sockaddr_dl *sdl; 471 { 472 int i; 473 long b; 474 caddr_t endp; 475 caddr_t p; 476 char *t, *r; 477 478 p = LLADDR(sdl); 479 endp = ((caddr_t)sdl) + sdl->sdl_len; 480 i = 0; 481 482 b = strtol(s, &t, 16); 483 if (t == s) 484 return 1; 485 486 *p++ = b; 487 ++i; 488 while ((p < endp) && (*t++ == ':')) { 489 b = strtol(t, &r, 16); 490 if (r == t) 491 break; 492 *p++ = b; 493 ++i; 494 t = r; 495 } 496 sdl->sdl_alen = i; 497 498 return 0; 499 } 500 501 void 502 usage() 503 { 504 extern char *__progname; 505 506 (void)fprintf(stderr, "usage: %s [-n] hostname\n", __progname); 507 (void)fprintf(stderr, "usage: %s [-n] -a\n", __progname); 508 (void)fprintf(stderr, "usage: %s -d hostname\n", __progname); 509 (void)fprintf(stderr, 510 "usage: %s -s hostname ether_addr [temp] [pub]\n", __progname); 511 (void)fprintf(stderr, "usage: %s -f filename\n", __progname); 512 exit(1); 513 } 514 515 int 516 rtmsg(cmd) 517 int cmd; 518 { 519 static int seq; 520 int rlen; 521 struct rt_msghdr *rtm; 522 char *cp; 523 int l; 524 525 rtm = &m_rtmsg.m_rtm; 526 cp = m_rtmsg.m_space; 527 errno = 0; 528 529 if (cmd == RTM_DELETE) 530 goto doit; 531 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 532 rtm->rtm_flags = flags; 533 rtm->rtm_version = RTM_VERSION; 534 535 switch (cmd) { 536 default: 537 errx(1, "internal wrong cmd"); 538 /*NOTREACHED*/ 539 case RTM_ADD: 540 rtm->rtm_addrs |= RTA_GATEWAY; 541 rtm->rtm_rmx.rmx_expire = expire_time; 542 rtm->rtm_inits = RTV_EXPIRE; 543 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 544 sin_m.sin_other = 0; 545 if (doing_proxy) { 546 if (export_only) 547 sin_m.sin_other = SIN_PROXY; 548 else { 549 rtm->rtm_addrs |= RTA_NETMASK; 550 rtm->rtm_flags &= ~RTF_HOST; 551 } 552 } 553 /* FALLTHROUGH */ 554 case RTM_GET: 555 rtm->rtm_addrs |= RTA_DST; 556 } 557 #define NEXTADDR(w, s) \ 558 if (rtm->rtm_addrs & (w)) { \ 559 (void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);} 560 561 NEXTADDR(RTA_DST, sin_m); 562 NEXTADDR(RTA_GATEWAY, sdl_m); 563 NEXTADDR(RTA_NETMASK, so_mask); 564 565 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 566 doit: 567 l = rtm->rtm_msglen; 568 rtm->rtm_seq = ++seq; 569 rtm->rtm_type = cmd; 570 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 571 if (errno != ESRCH || cmd != RTM_DELETE) { 572 warn("writing to routing socket"); 573 return (-1); 574 } 575 } 576 do { 577 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 578 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 579 if (l < 0) 580 warn("read from routing socket"); 581 return (0); 582 } 583 584 int 585 getinetaddr(host, inap) 586 const char *host; 587 struct in_addr *inap; 588 { 589 struct hostent *hp; 590 591 if (inet_aton(host, inap) == 1) 592 return (0); 593 if ((hp = gethostbyname(host)) == NULL) { 594 warnx("%s: %s\n", host, hstrerror(h_errno)); 595 return (-1); 596 } 597 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 598 return (0); 599 } 600
Indexes created Tue Sep 30 20:09:53 GMT 2025