arp.c revision 1.16
1 /* $NetBSD: arp.c,v 1.16 1997/03/07 07:04:43 mikel 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 #ifndef lint 40 static char copyright[] = 41 "@(#) 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 /* static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; */ 47 static char *rcsid = "$NetBSD: arp.c,v 1.16 1997/03/07 07:04:43 mikel Exp $"; 48 #endif /* not lint */ 49 50 /* 51 * arp - display, set, and delete arp table entries 52 */ 53 54 #include <sys/param.h> 55 #include <sys/file.h> 56 #include <sys/socket.h> 57 #include <sys/sysctl.h> 58 59 #include <net/if.h> 60 #include <net/if_dl.h> 61 #include <net/if_types.h> 62 #include <net/route.h> 63 #include <netinet/in.h> 64 #include <netinet/if_ether.h> 65 #include <arpa/inet.h> 66 67 #include <err.h> 68 #include <errno.h> 69 #include <netdb.h> 70 #include <nlist.h> 71 #include <paths.h> 72 #include <stdio.h> 73 #include <stdlib.h> 74 #include <string.h> 75 #include <unistd.h> 76 77 static int pid; 78 static int nflag; 79 static int s = -1; 80 81 int delete __P((const char *, const char *)); 82 void dump __P((u_long)); 83 void ether_print __P((const u_char *)); 84 int file __P((char *)); 85 void get __P((const char *)); 86 int getinetaddr __P((const char *, struct in_addr *)); 87 void getsocket __P((void)); 88 int rtmsg __P((int)); 89 int set __P((int, char **)); 90 void usage __P((void)); 91 92 int 93 main(argc, argv) 94 int argc; 95 char **argv; 96 { 97 int ch; 98 int op = 0; 99 100 pid = getpid(); 101 102 while ((ch = getopt(argc, argv, "andsf")) != -1) 103 switch((char)ch) { 104 case 'a': 105 case 'd': 106 case 's': 107 case 'f': 108 if (op) 109 usage(); 110 op = ch; 111 break; 112 case 'n': 113 nflag = 1; 114 break; 115 default: 116 usage(); 117 } 118 argc -= optind; 119 argv += optind; 120 121 switch((char)op) { 122 case 'a': 123 dump(0); 124 break; 125 case 'd': 126 if (argc < 1 || argc > 2) 127 usage(); 128 (void)delete(argv[0], argv[1]); 129 break; 130 case 's': 131 if (argc < 2 || argc > 5) 132 usage(); 133 return (set(argc, argv) ? 1 : 0); 134 case 'f': 135 if (argc != 1) 136 usage(); 137 return (file(argv[0])); 138 default: 139 if (argc != 1) 140 usage(); 141 get(argv[0]); 142 break; 143 } 144 return (0); 145 } 146 147 /* 148 * Process a file to set standard arp entries 149 */ 150 int 151 file(name) 152 char *name; 153 { 154 char line[100], arg[5][50], *args[5]; 155 int i, retval; 156 FILE *fp; 157 158 if ((fp = fopen(name, "r")) == NULL) 159 err(1, "cannot open %s", name); 160 args[0] = &arg[0][0]; 161 args[1] = &arg[1][0]; 162 args[2] = &arg[2][0]; 163 args[3] = &arg[3][0]; 164 args[4] = &arg[4][0]; 165 retval = 0; 166 while (fgets(line, 100, fp) != NULL) { 167 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 168 arg[3], arg[4]); 169 if (i < 2) { 170 warnx("bad line: %s", line); 171 retval = 1; 172 continue; 173 } 174 if (set(i, args)) 175 retval = 1; 176 } 177 fclose(fp); 178 return (retval); 179 } 180 181 void 182 getsocket() 183 { 184 if (s >= 0) 185 return; 186 s = socket(PF_ROUTE, SOCK_RAW, 0); 187 if (s < 0) 188 err(1, "socket"); 189 } 190 191 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 192 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 193 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 194 int expire_time, flags, export_only, doing_proxy, found_entry; 195 struct { 196 struct rt_msghdr m_rtm; 197 char m_space[512]; 198 } m_rtmsg; 199 200 /* 201 * Set an individual arp entry 202 */ 203 int 204 set(argc, argv) 205 int argc; 206 char **argv; 207 { 208 register struct sockaddr_inarp *sin; 209 register struct sockaddr_dl *sdl; 210 register struct rt_msghdr *rtm; 211 struct ether_addr *ea; 212 char *host = argv[0], *eaddr; 213 214 sin = &sin_m; 215 rtm = &(m_rtmsg.m_rtm); 216 eaddr = argv[1]; 217 218 getsocket(); 219 argc -= 2; 220 argv += 2; 221 sdl_m = blank_sdl; /* struct copy */ 222 sin_m = blank_sin; /* struct copy */ 223 if (getinetaddr(host, &sin->sin_addr) == -1) 224 return (1); 225 ea = ether_aton(eaddr); 226 if (ea != NULL) { 227 (void)memcpy(LLADDR(&sdl_m), ea, sizeof(struct ether_addr)); 228 sdl_m.sdl_alen = sizeof(struct ether_addr); 229 } 230 else 231 warnx("invalid Ethernet address '%s'", eaddr); 232 doing_proxy = flags = export_only = expire_time = 0; 233 while (argc-- > 0) { 234 if (strncmp(argv[0], "temp", 4) == 0) { 235 struct timeval time; 236 (void)gettimeofday(&time, 0); 237 expire_time = time.tv_sec + 20 * 60; 238 } 239 else if (strncmp(argv[0], "pub", 3) == 0) { 240 flags |= RTF_ANNOUNCE; 241 doing_proxy = SIN_PROXY; 242 } else if (strncmp(argv[0], "trail", 5) == 0) { 243 (void)printf( 244 "%s: Sending trailers is no longer supported\n", 245 host); 246 } 247 argv++; 248 } 249 tryagain: 250 if (rtmsg(RTM_GET) < 0) { 251 warn("%s", host); 252 return (1); 253 } 254 sin = (struct sockaddr_inarp *)(rtm + 1); 255 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 256 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 257 if (sdl->sdl_family == AF_LINK && 258 (rtm->rtm_flags & RTF_LLINFO) && 259 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 260 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 261 case IFT_ISO88024: case IFT_ISO88025: 262 goto overwrite; 263 } 264 if (doing_proxy == 0) { 265 (void)printf("set: can only proxy for %s\n", host); 266 return (1); 267 } 268 if (sin_m.sin_other & SIN_PROXY) { 269 (void)printf( 270 "set: proxy entry exists for non 802 device\n"); 271 return (1); 272 } 273 sin_m.sin_other = SIN_PROXY; 274 export_only = 1; 275 goto tryagain; 276 } 277 overwrite: 278 if (sdl->sdl_family != AF_LINK) { 279 (void)printf("cannot intuit interface index and type for %s\n", 280 host); 281 return (1); 282 } 283 sdl_m.sdl_type = sdl->sdl_type; 284 sdl_m.sdl_index = sdl->sdl_index; 285 return (rtmsg(RTM_ADD)); 286 } 287 288 /* 289 * Display an individual arp entry 290 */ 291 void 292 get(host) 293 const char *host; 294 { 295 struct sockaddr_inarp *sin; 296 297 sin = &sin_m; 298 sin_m = blank_sin; /* struct copy */ 299 if (getinetaddr(host, &sin->sin_addr) == -1) 300 exit(1); 301 dump(sin->sin_addr.s_addr); 302 if (found_entry == 0) { 303 (void)printf("%s (%s) -- no entry\n", host, 304 inet_ntoa(sin->sin_addr)); 305 exit(1); 306 } 307 } 308 309 /* 310 * Delete an arp entry 311 */ 312 int 313 delete(host, info) 314 const char *host; 315 const char *info; 316 { 317 register struct sockaddr_inarp *sin; 318 register struct rt_msghdr *rtm; 319 struct sockaddr_dl *sdl; 320 321 sin = &sin_m; 322 rtm = &m_rtmsg.m_rtm; 323 324 if (info && strncmp(info, "pro", 3) ) 325 export_only = 1; 326 getsocket(); 327 sin_m = blank_sin; /* struct copy */ 328 if (getinetaddr(host, &sin->sin_addr) == -1) 329 return (1); 330 tryagain: 331 if (rtmsg(RTM_GET) < 0) { 332 warn("%s", host); 333 return (1); 334 } 335 sin = (struct sockaddr_inarp *)(rtm + 1); 336 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 337 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 338 if (sdl->sdl_family == AF_LINK && 339 (rtm->rtm_flags & RTF_LLINFO) && 340 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 341 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 342 case IFT_ISO88024: case IFT_ISO88025: 343 goto delete; 344 } 345 } 346 if (sin_m.sin_other & SIN_PROXY) { 347 warnx("delete: can't locate %s", host); 348 return (1); 349 } else { 350 sin_m.sin_other = SIN_PROXY; 351 goto tryagain; 352 } 353 delete: 354 if (sdl->sdl_family != AF_LINK) { 355 (void)printf("cannot locate %s\n", host); 356 return (1); 357 } 358 if (rtmsg(RTM_DELETE)) 359 return (1); 360 (void)printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 361 return (0); 362 } 363 364 /* 365 * Dump the entire arp table 366 */ 367 void 368 dump(addr) 369 u_long addr; 370 { 371 int mib[6]; 372 size_t needed; 373 char *host, *lim, *buf, *next; 374 struct rt_msghdr *rtm; 375 struct sockaddr_inarp *sin; 376 struct sockaddr_dl *sdl; 377 extern int h_errno; 378 struct hostent *hp; 379 380 mib[0] = CTL_NET; 381 mib[1] = PF_ROUTE; 382 mib[2] = 0; 383 mib[3] = AF_INET; 384 mib[4] = NET_RT_FLAGS; 385 mib[5] = RTF_LLINFO; 386 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 387 err(1, "route-sysctl-estimate"); 388 if ((buf = malloc(needed)) == NULL) 389 err(1, "malloc"); 390 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 391 err(1, "actual retrieval of routing table"); 392 lim = buf + needed; 393 for (next = buf; next < lim; next += rtm->rtm_msglen) { 394 rtm = (struct rt_msghdr *)next; 395 sin = (struct sockaddr_inarp *)(rtm + 1); 396 sdl = (struct sockaddr_dl *)(sin + 1); 397 if (addr) { 398 if (addr != sin->sin_addr.s_addr) 399 continue; 400 found_entry = 1; 401 } 402 if (nflag == 0) 403 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 404 sizeof sin->sin_addr, AF_INET); 405 else 406 hp = 0; 407 if (hp) 408 host = hp->h_name; 409 else { 410 host = "?"; 411 if (h_errno == TRY_AGAIN) 412 nflag = 1; 413 } 414 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 415 if (sdl->sdl_alen) 416 ether_print((u_char *)LLADDR(sdl)); 417 else 418 (void)printf("(incomplete)"); 419 if (rtm->rtm_rmx.rmx_expire == 0) 420 (void)printf(" permanent"); 421 if (sin->sin_other & SIN_PROXY) 422 (void)printf(" published (proxy only)"); 423 if (rtm->rtm_addrs & RTA_NETMASK) { 424 sin = (struct sockaddr_inarp *) 425 (sdl->sdl_len + (char *)sdl); 426 if (sin->sin_addr.s_addr == 0xffffffff) 427 (void)printf(" published"); 428 if (sin->sin_len != 8) 429 (void)printf("(wierd)"); 430 } 431 (void)printf("\n"); 432 } 433 } 434 435 void 436 ether_print(cp) 437 const u_char *cp; 438 { 439 (void)printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], 440 cp[5]); 441 } 442 443 void 444 usage() 445 { 446 (void)fprintf(stderr, "usage: arp [-n] hostname\n"); 447 (void)fprintf(stderr, "usage: arp [-n] -a\n"); 448 (void)fprintf(stderr, "usage: arp -d hostname\n"); 449 (void)fprintf(stderr, 450 "usage: arp -s hostname ether_addr [temp] [pub]\n"); 451 (void)fprintf(stderr, "usage: arp -f filename\n"); 452 exit(1); 453 } 454 455 int 456 rtmsg(cmd) 457 int cmd; 458 { 459 static int seq; 460 int rlen; 461 register struct rt_msghdr *rtm; 462 register char *cp; 463 register int l; 464 465 rtm = &m_rtmsg.m_rtm; 466 cp = m_rtmsg.m_space; 467 errno = 0; 468 469 if (cmd == RTM_DELETE) 470 goto doit; 471 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 472 rtm->rtm_flags = flags; 473 rtm->rtm_version = RTM_VERSION; 474 475 switch (cmd) { 476 default: 477 errx(1, "internal wrong cmd"); 478 /*NOTREACHED*/ 479 case RTM_ADD: 480 rtm->rtm_addrs |= RTA_GATEWAY; 481 rtm->rtm_rmx.rmx_expire = expire_time; 482 rtm->rtm_inits = RTV_EXPIRE; 483 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 484 sin_m.sin_other = 0; 485 if (doing_proxy) { 486 if (export_only) 487 sin_m.sin_other = SIN_PROXY; 488 else { 489 rtm->rtm_addrs |= RTA_NETMASK; 490 rtm->rtm_flags &= ~RTF_HOST; 491 } 492 } 493 /* FALLTHROUGH */ 494 case RTM_GET: 495 rtm->rtm_addrs |= RTA_DST; 496 } 497 #define NEXTADDR(w, s) \ 498 if (rtm->rtm_addrs & (w)) { \ 499 (void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);} 500 501 NEXTADDR(RTA_DST, sin_m); 502 NEXTADDR(RTA_GATEWAY, sdl_m); 503 NEXTADDR(RTA_NETMASK, so_mask); 504 505 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 506 doit: 507 l = rtm->rtm_msglen; 508 rtm->rtm_seq = ++seq; 509 rtm->rtm_type = cmd; 510 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 511 if (errno != ESRCH || cmd != RTM_DELETE) { 512 warn("writing to routing socket"); 513 return (-1); 514 } 515 } 516 do { 517 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 518 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 519 if (l < 0) 520 warn("read from routing socket"); 521 return (0); 522 } 523 524 int 525 getinetaddr(host, inap) 526 const char *host; 527 struct in_addr *inap; 528 { 529 struct hostent *hp; 530 531 if (inet_aton(host, inap) == 1) 532 return (0); 533 if ((hp = gethostbyname(host)) == NULL) { 534 warnx("%s: %s\n", host, hstrerror(h_errno)); 535 return (-1); 536 } 537 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 538 return (0); 539 } 540
Indexes created Tue Sep 30 20:09:53 GMT 2025