arp.c revision 1.8
1 /* 2 * Copyright (c) 1984, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Sun Microsystems, Inc. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 static char copyright[] = 39 "@(#) Copyright (c) 1984, 1993\n\ 40 The Regents of the University of California. All rights reserved.\n"; 41 #endif /* not lint */ 42 43 #ifndef lint 44 /*static char sccsid[] = "from: @(#)arp.c 8.2 (Berkeley) 1/2/94";*/ 45 static char *rcsid = "$Id: arp.c,v 1.8 1995/02/27 22:00:14 chopps Exp $"; 46 #endif /* not lint */ 47 48 /* 49 * arp - display, set, and delete arp table entries 50 */ 51 52 #include <sys/param.h> 53 #include <sys/file.h> 54 #include <sys/socket.h> 55 #include <sys/sysctl.h> 56 57 #include <net/if.h> 58 #include <net/if_dl.h> 59 #include <net/if_types.h> 60 #include <net/route.h> 61 #include <netinet/in.h> 62 #include <netinet/if_ether.h> 63 #include <arpa/inet.h> 64 65 #include <netdb.h> 66 #include <errno.h> 67 #include <err.h> 68 #include <nlist.h> 69 #include <stdio.h> 70 #include <stdlib.h> 71 #include <paths.h> 72 73 int delete __P((const char *, const char *)); 74 void dump __P((u_long)); 75 int ether_aton __P((const char *, u_char *)); 76 void ether_print __P((const u_char *)); 77 int file __P((char *)); 78 void get __P((const char *)); 79 int getinetaddr __P((const char *, struct in_addr *)); 80 void getsocket __P((void)); 81 int rtmsg __P((int)); 82 int set __P((int, char **)); 83 void usage __P((void)); 84 85 static int pid; 86 static int nflag; 87 static int s = -1; 88 89 int 90 main(argc, argv) 91 int argc; 92 char **argv; 93 { 94 int ch; 95 96 pid = getpid(); 97 while ((ch = getopt(argc, argv, "andsf")) != EOF) 98 switch((char)ch) { 99 case 'a': 100 dump(0); 101 return (0); 102 case 'd': 103 if (argc < 3 || argc > 4) 104 usage(); 105 (void)delete(argv[2], argv[3]); 106 return (0); 107 case 'n': 108 nflag = 1; 109 break; 110 case 's': 111 if (argc < 4 || argc > 7) 112 usage(); 113 return (set(argc-2, &argv[2]) ? 1 : 0); 114 case 'f': 115 if (argc != 3) 116 usage(); 117 return (file(argv[2])); 118 case '?': 119 default: 120 usage(); 121 } 122 if (argc == 2 || (argc == 3 && nflag)) 123 get(argv[argc - 1]); 124 else 125 usage(); 126 return (0); 127 } 128 129 /* 130 * Process a file to set standard arp entries 131 */ 132 int 133 file(name) 134 char *name; 135 { 136 char line[100], arg[5][50], *args[5]; 137 int i, retval; 138 FILE *fp; 139 140 if ((fp = fopen(name, "r")) == NULL) 141 err(1, "cannot open %s", name); 142 args[0] = &arg[0][0]; 143 args[1] = &arg[1][0]; 144 args[2] = &arg[2][0]; 145 args[3] = &arg[3][0]; 146 args[4] = &arg[4][0]; 147 retval = 0; 148 while (fgets(line, 100, fp) != NULL) { 149 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 150 arg[3], arg[4]); 151 if (i < 2) { 152 warnx("bad line: %s", line); 153 retval = 1; 154 continue; 155 } 156 if (set(i, args)) 157 retval = 1; 158 } 159 fclose(fp); 160 return (retval); 161 } 162 163 void 164 getsocket() 165 { 166 if (s >= 0) 167 return; 168 s = socket(PF_ROUTE, SOCK_RAW, 0); 169 if (s < 0) 170 err(1, "socket"); 171 } 172 173 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 174 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 175 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 176 int expire_time, flags, export_only, doing_proxy, found_entry; 177 struct { 178 struct rt_msghdr m_rtm; 179 char m_space[512]; 180 } m_rtmsg; 181 182 /* 183 * Set an individual arp entry 184 */ 185 int 186 set(argc, argv) 187 int argc; 188 char **argv; 189 { 190 register struct sockaddr_inarp *sin; 191 register struct sockaddr_dl *sdl; 192 register struct rt_msghdr *rtm; 193 u_char *ea; 194 char *host = argv[0], *eaddr; 195 196 sin = &sin_m; 197 rtm = &(m_rtmsg.m_rtm); 198 eaddr = argv[1]; 199 200 getsocket(); 201 argc -= 2; 202 argv += 2; 203 sdl_m = blank_sdl; /* struct copy */ 204 sin_m = blank_sin; /* struct copy */ 205 if (getinetaddr(host, &sin->sin_addr) == -1) 206 return (1); 207 ea = (u_char *)LLADDR(&sdl_m); 208 if (ether_aton(eaddr, ea) == 0) 209 sdl_m.sdl_alen = 6; 210 doing_proxy = flags = export_only = expire_time = 0; 211 while (argc-- > 0) { 212 if (strncmp(argv[0], "temp", 4) == 0) { 213 struct timeval time; 214 (void)gettimeofday(&time, 0); 215 expire_time = time.tv_sec + 20 * 60; 216 } 217 else if (strncmp(argv[0], "pub", 3) == 0) { 218 flags |= RTF_ANNOUNCE; 219 doing_proxy = SIN_PROXY; 220 } else if (strncmp(argv[0], "trail", 5) == 0) { 221 (void)printf( 222 "%s: Sending trailers is no longer supported\n", 223 host); 224 } 225 argv++; 226 } 227 tryagain: 228 if (rtmsg(RTM_GET) < 0) { 229 warn("%s", host); 230 return (1); 231 } 232 sin = (struct sockaddr_inarp *)(rtm + 1); 233 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 234 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 235 if (sdl->sdl_family == AF_LINK && 236 (rtm->rtm_flags & RTF_LLINFO) && 237 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 238 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 239 case IFT_ISO88024: case IFT_ISO88025: 240 goto overwrite; 241 } 242 if (doing_proxy == 0) { 243 (void)printf("set: can only proxy for %s\n", host); 244 return (1); 245 } 246 if (sin_m.sin_other & SIN_PROXY) { 247 (void)printf( 248 "set: proxy entry exists for non 802 device\n"); 249 return (1); 250 } 251 sin_m.sin_other = SIN_PROXY; 252 export_only = 1; 253 goto tryagain; 254 } 255 overwrite: 256 if (sdl->sdl_family != AF_LINK) { 257 (void)printf("cannot intuit interface index and type for %s\n", 258 host); 259 return (1); 260 } 261 sdl_m.sdl_type = sdl->sdl_type; 262 sdl_m.sdl_index = sdl->sdl_index; 263 return (rtmsg(RTM_ADD)); 264 } 265 266 /* 267 * Display an individual arp entry 268 */ 269 void 270 get(host) 271 const char *host; 272 { 273 struct sockaddr_inarp *sin; 274 u_char *ea; 275 276 sin = &sin_m; 277 sin_m = blank_sin; /* struct copy */ 278 if (getinetaddr(host, &sin->sin_addr) == -1) 279 exit(1); 280 dump(sin->sin_addr.s_addr); 281 if (found_entry == 0) { 282 (void)printf("%s (%s) -- no entry\n", host, 283 inet_ntoa(sin->sin_addr)); 284 exit(1); 285 } 286 } 287 288 /* 289 * Delete an arp entry 290 */ 291 int 292 delete(host, info) 293 const char *host; 294 const char *info; 295 { 296 register struct sockaddr_inarp *sin; 297 register struct rt_msghdr *rtm; 298 struct sockaddr_dl *sdl; 299 u_char *ea; 300 char *eaddr; 301 302 sin = &sin_m; 303 rtm = &m_rtmsg.m_rtm; 304 305 if (info && strncmp(info, "pro", 3) ) 306 export_only = 1; 307 getsocket(); 308 sin_m = blank_sin; /* struct copy */ 309 if (getinetaddr(host, &sin->sin_addr) == -1) 310 return (1); 311 tryagain: 312 if (rtmsg(RTM_GET) < 0) { 313 warn("%s", host); 314 return (1); 315 } 316 sin = (struct sockaddr_inarp *)(rtm + 1); 317 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 318 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 319 if (sdl->sdl_family == AF_LINK && 320 (rtm->rtm_flags & RTF_LLINFO) && 321 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 322 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 323 case IFT_ISO88024: case IFT_ISO88025: 324 goto delete; 325 } 326 } 327 if (sin_m.sin_other & SIN_PROXY) { 328 warnx("delete: can't locate %s", host); 329 return (1); 330 } else { 331 sin_m.sin_other = SIN_PROXY; 332 goto tryagain; 333 } 334 delete: 335 if (sdl->sdl_family != AF_LINK) { 336 (void)printf("cannot locate %s\n", host); 337 return (1); 338 } 339 if (rtmsg(RTM_DELETE)) 340 return (1); 341 (void)printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 342 return (0); 343 } 344 345 /* 346 * Dump the entire arp table 347 */ 348 void 349 dump(addr) 350 u_long addr; 351 { 352 int mib[6]; 353 size_t needed; 354 char *host, *lim, *buf, *next; 355 struct rt_msghdr *rtm; 356 struct sockaddr_inarp *sin; 357 struct sockaddr_dl *sdl; 358 extern int h_errno; 359 struct hostent *hp; 360 361 mib[0] = CTL_NET; 362 mib[1] = PF_ROUTE; 363 mib[2] = 0; 364 mib[3] = AF_INET; 365 mib[4] = NET_RT_FLAGS; 366 mib[5] = RTF_LLINFO; 367 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 368 err(1, "route-sysctl-estimate"); 369 if ((buf = malloc(needed)) == NULL) 370 err(1, "malloc"); 371 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 372 err(1, "actual retrieval of routing table"); 373 lim = buf + needed; 374 for (next = buf; next < lim; next += rtm->rtm_msglen) { 375 rtm = (struct rt_msghdr *)next; 376 sin = (struct sockaddr_inarp *)(rtm + 1); 377 sdl = (struct sockaddr_dl *)(sin + 1); 378 if (addr) { 379 if (addr != sin->sin_addr.s_addr) 380 continue; 381 found_entry = 1; 382 } 383 if (nflag == 0) 384 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 385 sizeof sin->sin_addr, AF_INET); 386 else 387 hp = 0; 388 if (hp) 389 host = hp->h_name; 390 else { 391 host = "?"; 392 if (h_errno == TRY_AGAIN) 393 nflag = 1; 394 } 395 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 396 if (sdl->sdl_alen) 397 ether_print(LLADDR(sdl)); 398 else 399 (void)printf("(incomplete)"); 400 if (rtm->rtm_rmx.rmx_expire == 0) 401 (void)printf(" permanent"); 402 if (sin->sin_other & SIN_PROXY) 403 (void)printf(" published (proxy only)"); 404 if (rtm->rtm_addrs & RTA_NETMASK) { 405 sin = (struct sockaddr_inarp *) 406 (sdl->sdl_len + (char *)sdl); 407 if (sin->sin_addr.s_addr == 0xffffffff) 408 (void)printf(" published"); 409 if (sin->sin_len != 8) 410 (void)printf("(wierd)"); 411 } 412 (void)printf("\n"); 413 } 414 } 415 416 void 417 ether_print(cp) 418 const u_char *cp; 419 { 420 (void)printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], 421 cp[5]); 422 } 423 424 int 425 ether_aton(a, n) 426 const char *a; 427 u_char *n; 428 { 429 int i, o[6]; 430 431 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], &o[3], &o[4], 432 &o[5]); 433 if (i != 6) { 434 warnx("invalid Ethernet address '%s'", a); 435 return (1); 436 } 437 for (i=0; i<6; i++) 438 n[i] = o[i]; 439 return (0); 440 } 441 442 void 443 usage() 444 { 445 (void)fprintf(stderr, "usage: arp [-n] hostname\n"); 446 (void)fprintf(stderr, "usage: arp [-n] -a\n"); 447 (void)fprintf(stderr, "usage: arp -d hostname\n"); 448 (void)fprintf(stderr, 449 "usage: arp -s hostname ether_addr [temp] [pub]\n"); 450 (void)fprintf(stderr, "usage: arp -f filename\n"); 451 exit(1); 452 } 453 454 int 455 rtmsg(cmd) 456 int cmd; 457 { 458 static int seq; 459 int rlen; 460 register struct rt_msghdr *rtm; 461 register char *cp; 462 register int l; 463 464 rtm = &m_rtmsg.m_rtm; 465 cp = m_rtmsg.m_space; 466 errno = 0; 467 468 if (cmd == RTM_DELETE) 469 goto doit; 470 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 471 rtm->rtm_flags = flags; 472 rtm->rtm_version = RTM_VERSION; 473 474 switch (cmd) { 475 default: 476 errx(1, "internal wrong cmd"); 477 /*NOTREACHED*/ 478 case RTM_ADD: 479 rtm->rtm_addrs |= RTA_GATEWAY; 480 rtm->rtm_rmx.rmx_expire = expire_time; 481 rtm->rtm_inits = RTV_EXPIRE; 482 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 483 sin_m.sin_other = 0; 484 if (doing_proxy) { 485 if (export_only) 486 sin_m.sin_other = SIN_PROXY; 487 else { 488 rtm->rtm_addrs |= RTA_NETMASK; 489 rtm->rtm_flags &= ~RTF_HOST; 490 } 491 } 492 /* FALLTHROUGH */ 493 case RTM_GET: 494 rtm->rtm_addrs |= RTA_DST; 495 } 496 #define NEXTADDR(w, s) \ 497 if (rtm->rtm_addrs & (w)) { \ 498 (void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);} 499 500 NEXTADDR(RTA_DST, sin_m); 501 NEXTADDR(RTA_GATEWAY, sdl_m); 502 NEXTADDR(RTA_NETMASK, so_mask); 503 504 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 505 doit: 506 l = rtm->rtm_msglen; 507 rtm->rtm_seq = ++seq; 508 rtm->rtm_type = cmd; 509 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 510 if (errno != ESRCH || cmd != RTM_DELETE) { 511 warn("writing to routing socket"); 512 return (-1); 513 } 514 } 515 do { 516 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 517 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 518 if (l < 0) 519 warn("read from routing socket"); 520 return (0); 521 } 522 523 int 524 getinetaddr(host, inap) 525 const char *host; 526 struct in_addr *inap; 527 { 528 extern char *__progname; /* Program name, from crt0. */ 529 struct hostent *hp; 530 u_long addr; 531 532 if ((inap->s_addr = inet_addr(host)) != INADDR_NONE) 533 return (0); 534 if ((hp = gethostbyname(host)) == NULL) { 535 (void)fprintf(stderr, "%s: %s: ", __progname, host); 536 herror(NULL); 537 return (-1); 538 } 539 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 540 return (0); 541 } 542
Indexes created Tue Sep 30 20:09:53 GMT 2025