arp.c revision 1.12
1 /* $NetBSD: arp.c,v 1.12 1995/04/24 13:25:18 cgd 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[] = "from: @(#)arp.c 8.2 (Berkeley) 1/2/94";*/ 47 static char *rcsid = "$NetBSD: arp.c,v 1.12 1995/04/24 13:25:18 cgd 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 <netdb.h> 68 #include <errno.h> 69 #include <err.h> 70 #include <nlist.h> 71 #include <stdio.h> 72 #include <stdlib.h> 73 #include <string.h> 74 #include <paths.h> 75 76 int delete __P((const char *, const char *)); 77 void dump __P((u_long)); 78 int ether_aton __P((const char *, u_char *)); 79 void ether_print __P((const u_char *)); 80 int file __P((char *)); 81 void get __P((const char *)); 82 int getinetaddr __P((const char *, struct in_addr *)); 83 void getsocket __P((void)); 84 int rtmsg __P((int)); 85 int set __P((int, char **)); 86 void usage __P((void)); 87 88 static int pid; 89 static int nflag; 90 static int s = -1; 91 92 int 93 main(argc, argv) 94 int argc; 95 char **argv; 96 { 97 int ch; 98 99 pid = getpid(); 100 while ((ch = getopt(argc, argv, "andsf")) != EOF) 101 switch((char)ch) { 102 case 'a': 103 dump(0); 104 return (0); 105 case 'd': 106 if (argc < 3 || argc > 4) 107 usage(); 108 (void)delete(argv[2], argv[3]); 109 return (0); 110 case 'n': 111 nflag = 1; 112 break; 113 case 's': 114 if (argc < 4 || argc > 7) 115 usage(); 116 return (set(argc-2, &argv[2]) ? 1 : 0); 117 case 'f': 118 if (argc != 3) 119 usage(); 120 return (file(argv[2])); 121 case '?': 122 default: 123 usage(); 124 } 125 if (argc == 2 || (argc == 3 && nflag)) 126 get(argv[argc - 1]); 127 else 128 usage(); 129 return (0); 130 } 131 132 /* 133 * Process a file to set standard arp entries 134 */ 135 int 136 file(name) 137 char *name; 138 { 139 char line[100], arg[5][50], *args[5]; 140 int i, retval; 141 FILE *fp; 142 143 if ((fp = fopen(name, "r")) == NULL) 144 err(1, "cannot open %s", name); 145 args[0] = &arg[0][0]; 146 args[1] = &arg[1][0]; 147 args[2] = &arg[2][0]; 148 args[3] = &arg[3][0]; 149 args[4] = &arg[4][0]; 150 retval = 0; 151 while (fgets(line, 100, fp) != NULL) { 152 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 153 arg[3], arg[4]); 154 if (i < 2) { 155 warnx("bad line: %s", line); 156 retval = 1; 157 continue; 158 } 159 if (set(i, args)) 160 retval = 1; 161 } 162 fclose(fp); 163 return (retval); 164 } 165 166 void 167 getsocket() 168 { 169 if (s >= 0) 170 return; 171 s = socket(PF_ROUTE, SOCK_RAW, 0); 172 if (s < 0) 173 err(1, "socket"); 174 } 175 176 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 177 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 178 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 179 int expire_time, flags, export_only, doing_proxy, found_entry; 180 struct { 181 struct rt_msghdr m_rtm; 182 char m_space[512]; 183 } m_rtmsg; 184 185 /* 186 * Set an individual arp entry 187 */ 188 int 189 set(argc, argv) 190 int argc; 191 char **argv; 192 { 193 register struct sockaddr_inarp *sin; 194 register struct sockaddr_dl *sdl; 195 register struct rt_msghdr *rtm; 196 u_char *ea; 197 char *host = argv[0], *eaddr; 198 199 sin = &sin_m; 200 rtm = &(m_rtmsg.m_rtm); 201 eaddr = argv[1]; 202 203 getsocket(); 204 argc -= 2; 205 argv += 2; 206 sdl_m = blank_sdl; /* struct copy */ 207 sin_m = blank_sin; /* struct copy */ 208 if (getinetaddr(host, &sin->sin_addr) == -1) 209 return (1); 210 ea = (u_char *)LLADDR(&sdl_m); 211 if (ether_aton(eaddr, ea) == 0) 212 sdl_m.sdl_alen = 6; 213 doing_proxy = flags = export_only = expire_time = 0; 214 while (argc-- > 0) { 215 if (strncmp(argv[0], "temp", 4) == 0) { 216 struct timeval time; 217 (void)gettimeofday(&time, 0); 218 expire_time = time.tv_sec + 20 * 60; 219 } 220 else if (strncmp(argv[0], "pub", 3) == 0) { 221 flags |= RTF_ANNOUNCE; 222 doing_proxy = SIN_PROXY; 223 } else if (strncmp(argv[0], "trail", 5) == 0) { 224 (void)printf( 225 "%s: Sending trailers is no longer supported\n", 226 host); 227 } 228 argv++; 229 } 230 tryagain: 231 if (rtmsg(RTM_GET) < 0) { 232 warn("%s", host); 233 return (1); 234 } 235 sin = (struct sockaddr_inarp *)(rtm + 1); 236 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 237 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 238 if (sdl->sdl_family == AF_LINK && 239 (rtm->rtm_flags & RTF_LLINFO) && 240 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 241 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 242 case IFT_ISO88024: case IFT_ISO88025: 243 goto overwrite; 244 } 245 if (doing_proxy == 0) { 246 (void)printf("set: can only proxy for %s\n", host); 247 return (1); 248 } 249 if (sin_m.sin_other & SIN_PROXY) { 250 (void)printf( 251 "set: proxy entry exists for non 802 device\n"); 252 return (1); 253 } 254 sin_m.sin_other = SIN_PROXY; 255 export_only = 1; 256 goto tryagain; 257 } 258 overwrite: 259 if (sdl->sdl_family != AF_LINK) { 260 (void)printf("cannot intuit interface index and type for %s\n", 261 host); 262 return (1); 263 } 264 sdl_m.sdl_type = sdl->sdl_type; 265 sdl_m.sdl_index = sdl->sdl_index; 266 return (rtmsg(RTM_ADD)); 267 } 268 269 /* 270 * Display an individual arp entry 271 */ 272 void 273 get(host) 274 const char *host; 275 { 276 struct sockaddr_inarp *sin; 277 u_char *ea; 278 279 sin = &sin_m; 280 sin_m = blank_sin; /* struct copy */ 281 if (getinetaddr(host, &sin->sin_addr) == -1) 282 exit(1); 283 dump(sin->sin_addr.s_addr); 284 if (found_entry == 0) { 285 (void)printf("%s (%s) -- no entry\n", host, 286 inet_ntoa(sin->sin_addr)); 287 exit(1); 288 } 289 } 290 291 /* 292 * Delete an arp entry 293 */ 294 int 295 delete(host, info) 296 const char *host; 297 const char *info; 298 { 299 register struct sockaddr_inarp *sin; 300 register struct rt_msghdr *rtm; 301 struct sockaddr_dl *sdl; 302 u_char *ea; 303 char *eaddr; 304 305 sin = &sin_m; 306 rtm = &m_rtmsg.m_rtm; 307 308 if (info && strncmp(info, "pro", 3) ) 309 export_only = 1; 310 getsocket(); 311 sin_m = blank_sin; /* struct copy */ 312 if (getinetaddr(host, &sin->sin_addr) == -1) 313 return (1); 314 tryagain: 315 if (rtmsg(RTM_GET) < 0) { 316 warn("%s", host); 317 return (1); 318 } 319 sin = (struct sockaddr_inarp *)(rtm + 1); 320 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 321 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 322 if (sdl->sdl_family == AF_LINK && 323 (rtm->rtm_flags & RTF_LLINFO) && 324 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 325 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 326 case IFT_ISO88024: case IFT_ISO88025: 327 goto delete; 328 } 329 } 330 if (sin_m.sin_other & SIN_PROXY) { 331 warnx("delete: can't locate %s", host); 332 return (1); 333 } else { 334 sin_m.sin_other = SIN_PROXY; 335 goto tryagain; 336 } 337 delete: 338 if (sdl->sdl_family != AF_LINK) { 339 (void)printf("cannot locate %s\n", host); 340 return (1); 341 } 342 if (rtmsg(RTM_DELETE)) 343 return (1); 344 (void)printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 345 return (0); 346 } 347 348 /* 349 * Dump the entire arp table 350 */ 351 void 352 dump(addr) 353 u_long addr; 354 { 355 int mib[6]; 356 size_t needed; 357 char *host, *lim, *buf, *next; 358 struct rt_msghdr *rtm; 359 struct sockaddr_inarp *sin; 360 struct sockaddr_dl *sdl; 361 extern int h_errno; 362 struct hostent *hp; 363 364 mib[0] = CTL_NET; 365 mib[1] = PF_ROUTE; 366 mib[2] = 0; 367 mib[3] = AF_INET; 368 mib[4] = NET_RT_FLAGS; 369 mib[5] = RTF_LLINFO; 370 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 371 err(1, "route-sysctl-estimate"); 372 if ((buf = malloc(needed)) == NULL) 373 err(1, "malloc"); 374 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 375 err(1, "actual retrieval of routing table"); 376 lim = buf + needed; 377 for (next = buf; next < lim; next += rtm->rtm_msglen) { 378 rtm = (struct rt_msghdr *)next; 379 sin = (struct sockaddr_inarp *)(rtm + 1); 380 sdl = (struct sockaddr_dl *)(sin + 1); 381 if (addr) { 382 if (addr != sin->sin_addr.s_addr) 383 continue; 384 found_entry = 1; 385 } 386 if (nflag == 0) 387 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 388 sizeof sin->sin_addr, AF_INET); 389 else 390 hp = 0; 391 if (hp) 392 host = hp->h_name; 393 else { 394 host = "?"; 395 if (h_errno == TRY_AGAIN) 396 nflag = 1; 397 } 398 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 399 if (sdl->sdl_alen) 400 ether_print(LLADDR(sdl)); 401 else 402 (void)printf("(incomplete)"); 403 if (rtm->rtm_rmx.rmx_expire == 0) 404 (void)printf(" permanent"); 405 if (sin->sin_other & SIN_PROXY) 406 (void)printf(" published (proxy only)"); 407 if (rtm->rtm_addrs & RTA_NETMASK) { 408 sin = (struct sockaddr_inarp *) 409 (sdl->sdl_len + (char *)sdl); 410 if (sin->sin_addr.s_addr == 0xffffffff) 411 (void)printf(" published"); 412 if (sin->sin_len != 8) 413 (void)printf("(wierd)"); 414 } 415 (void)printf("\n"); 416 } 417 } 418 419 void 420 ether_print(cp) 421 const u_char *cp; 422 { 423 (void)printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], 424 cp[5]); 425 } 426 427 int 428 ether_aton(a, n) 429 const char *a; 430 u_char *n; 431 { 432 int i, o[6]; 433 434 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], &o[3], &o[4], 435 &o[5]); 436 if (i != 6) { 437 warnx("invalid Ethernet address '%s'", a); 438 return (1); 439 } 440 for (i=0; i<6; i++) 441 n[i] = o[i]; 442 return (0); 443 } 444 445 void 446 usage() 447 { 448 (void)fprintf(stderr, "usage: arp [-n] hostname\n"); 449 (void)fprintf(stderr, "usage: arp [-n] -a\n"); 450 (void)fprintf(stderr, "usage: arp -d hostname\n"); 451 (void)fprintf(stderr, 452 "usage: arp -s hostname ether_addr [temp] [pub]\n"); 453 (void)fprintf(stderr, "usage: arp -f filename\n"); 454 exit(1); 455 } 456 457 int 458 rtmsg(cmd) 459 int cmd; 460 { 461 static int seq; 462 int rlen; 463 register struct rt_msghdr *rtm; 464 register char *cp; 465 register int l; 466 467 rtm = &m_rtmsg.m_rtm; 468 cp = m_rtmsg.m_space; 469 errno = 0; 470 471 if (cmd == RTM_DELETE) 472 goto doit; 473 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 474 rtm->rtm_flags = flags; 475 rtm->rtm_version = RTM_VERSION; 476 477 switch (cmd) { 478 default: 479 errx(1, "internal wrong cmd"); 480 /*NOTREACHED*/ 481 case RTM_ADD: 482 rtm->rtm_addrs |= RTA_GATEWAY; 483 rtm->rtm_rmx.rmx_expire = expire_time; 484 rtm->rtm_inits = RTV_EXPIRE; 485 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 486 sin_m.sin_other = 0; 487 if (doing_proxy) { 488 if (export_only) 489 sin_m.sin_other = SIN_PROXY; 490 else { 491 rtm->rtm_addrs |= RTA_NETMASK; 492 rtm->rtm_flags &= ~RTF_HOST; 493 } 494 } 495 /* FALLTHROUGH */ 496 case RTM_GET: 497 rtm->rtm_addrs |= RTA_DST; 498 } 499 #define NEXTADDR(w, s) \ 500 if (rtm->rtm_addrs & (w)) { \ 501 (void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);} 502 503 NEXTADDR(RTA_DST, sin_m); 504 NEXTADDR(RTA_GATEWAY, sdl_m); 505 NEXTADDR(RTA_NETMASK, so_mask); 506 507 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 508 doit: 509 l = rtm->rtm_msglen; 510 rtm->rtm_seq = ++seq; 511 rtm->rtm_type = cmd; 512 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 513 if (errno != ESRCH || cmd != RTM_DELETE) { 514 warn("writing to routing socket"); 515 return (-1); 516 } 517 } 518 do { 519 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 520 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 521 if (l < 0) 522 warn("read from routing socket"); 523 return (0); 524 } 525 526 int 527 getinetaddr(host, inap) 528 const char *host; 529 struct in_addr *inap; 530 { 531 extern char *__progname; /* Program name, from crt0. */ 532 struct hostent *hp; 533 u_long addr; 534 535 if (inet_aton(host, inap) == 1) 536 return (0); 537 if ((hp = gethostbyname(host)) == NULL) { 538 (void)fprintf(stderr, "%s: %s: ", __progname, host); 539 herror(NULL); 540 return (-1); 541 } 542 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 543 return (0); 544 } 545
Indexes created Tue Sep 30 20:09:53 GMT 2025