arp.c revision 1.6
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 1.6 1995/02/25 08:49:51 chopps Exp $"; 46 #endif /* not lint */ 47 48 /* 49 * arp - display, set, and delete arp table entries 50 */ 51 52 53 #include <sys/param.h> 54 #include <sys/file.h> 55 #include <sys/socket.h> 56 #include <sys/sysctl.h> 57 58 #include <net/if.h> 59 #include <net/if_dl.h> 60 #include <net/if_types.h> 61 #include <net/route.h> 62 63 #include <netinet/in.h> 64 #include <netinet/if_ether.h> 65 66 #include <arpa/inet.h> 67 68 #include <netdb.h> 69 #include <errno.h> 70 #include <nlist.h> 71 #include <stdio.h> 72 #include <paths.h> 73 74 extern int errno; 75 static int pid; 76 static int kflag; 77 static int nflag; 78 static int s = -1; 79 80 main(argc, argv) 81 int argc; 82 char **argv; 83 { 84 int ch; 85 86 pid = getpid(); 87 while ((ch = getopt(argc, argv, "andsf")) != EOF) 88 switch((char)ch) { 89 case 'a': 90 dump(0); 91 exit(0); 92 case 'd': 93 if (argc < 3 || argc > 4) 94 usage(); 95 delete(argv[2], argv[3]); 96 exit(0); 97 case 'n': 98 nflag = 1; 99 continue; 100 case 's': 101 if (argc < 4 || argc > 7) 102 usage(); 103 exit(set(argc-2, &argv[2]) ? 1 : 0); 104 case 'f': 105 if (argc != 3) 106 usage(); 107 exit(file(agrv[2])); 108 case '?': 109 default: 110 usage(); 111 } 112 if (argc != 2) 113 usage(); 114 get(argv[1]); 115 exit(0); 116 } 117 118 /* 119 * Process a file to set standard arp entries 120 */ 121 file(name) 122 char *name; 123 { 124 FILE *fp; 125 int i, retval; 126 char line[100], arg[5][50], *args[5]; 127 128 if ((fp = fopen(name, "r")) == NULL) { 129 fprintf(stderr, "arp: cannot open %s\n", name); 130 exit(1); 131 } 132 args[0] = &arg[0][0]; 133 args[1] = &arg[1][0]; 134 args[2] = &arg[2][0]; 135 args[3] = &arg[3][0]; 136 args[4] = &arg[4][0]; 137 retval = 0; 138 while(fgets(line, 100, fp) != NULL) { 139 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 140 arg[3], arg[4]); 141 if (i < 2) { 142 fprintf(stderr, "arp: bad line: %s\n", line); 143 retval = 1; 144 continue; 145 } 146 if (set(i, args)) 147 retval = 1; 148 } 149 fclose(fp); 150 return (retval); 151 } 152 153 getsocket() { 154 if (s < 0) { 155 s = socket(PF_ROUTE, SOCK_RAW, 0); 156 if (s < 0) { 157 perror("arp: socket"); 158 exit(1); 159 } 160 } 161 } 162 163 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 164 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 165 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 166 int expire_time, flags, export_only, doing_proxy, found_entry; 167 struct { 168 struct rt_msghdr m_rtm; 169 char m_space[512]; 170 } m_rtmsg; 171 172 /* 173 * Set an individual arp entry 174 */ 175 set(argc, argv) 176 int argc; 177 char **argv; 178 { 179 struct hostent *hp; 180 register struct sockaddr_inarp *sin = &sin_m; 181 register struct sockaddr_dl *sdl; 182 register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 183 u_char *ea; 184 char *host = argv[0], *eaddr = argv[1]; 185 186 getsocket(); 187 argc -= 2; 188 argv += 2; 189 sdl_m = blank_sdl; 190 sin_m = blank_sin; 191 sin->sin_addr.s_addr = inet_addr(host); 192 if (sin->sin_addr.s_addr == -1) { 193 if (!(hp = gethostbyname(host))) { 194 fprintf(stderr, "arp: %s: ", host); 195 herror((char *)NULL); 196 return (1); 197 } 198 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 199 sizeof sin->sin_addr); 200 } 201 ea = (u_char *)LLADDR(&sdl_m); 202 if (ether_aton(eaddr, ea) == 0) 203 sdl_m.sdl_alen = 6; 204 doing_proxy = flags = export_only = expire_time = 0; 205 while (argc-- > 0) { 206 if (strncmp(argv[0], "temp", 4) == 0) { 207 struct timeval time; 208 gettimeofday(&time, 0); 209 expire_time = time.tv_sec + 20 * 60; 210 } 211 else if (strncmp(argv[0], "pub", 3) == 0) { 212 flags |= RTF_ANNOUNCE; 213 doing_proxy = SIN_PROXY; 214 } else if (strncmp(argv[0], "trail", 5) == 0) { 215 printf("%s: Sending trailers is no longer supported\n", 216 host); 217 } 218 argv++; 219 } 220 tryagain: 221 if (rtmsg(RTM_GET) < 0) { 222 perror(host); 223 return (1); 224 } 225 sin = (struct sockaddr_inarp *)(rtm + 1); 226 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 227 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 228 if (sdl->sdl_family == AF_LINK && 229 (rtm->rtm_flags & RTF_LLINFO) && 230 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 231 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 232 case IFT_ISO88024: case IFT_ISO88025: 233 goto overwrite; 234 } 235 if (doing_proxy == 0) { 236 printf("set: can only proxy for %s\n", host); 237 return (1); 238 } 239 if (sin_m.sin_other & SIN_PROXY) { 240 printf("set: proxy entry exists for non 802 device\n"); 241 return(1); 242 } 243 sin_m.sin_other = SIN_PROXY; 244 export_only = 1; 245 goto tryagain; 246 } 247 overwrite: 248 if (sdl->sdl_family != AF_LINK) { 249 printf("cannot intuit interface index and type for %s\n", host); 250 return (1); 251 } 252 sdl_m.sdl_type = sdl->sdl_type; 253 sdl_m.sdl_index = sdl->sdl_index; 254 return (rtmsg(RTM_ADD)); 255 } 256 257 /* 258 * Display an individual arp entry 259 */ 260 get(host) 261 char *host; 262 { 263 struct hostent *hp; 264 struct sockaddr_inarp *sin = &sin_m; 265 u_char *ea; 266 267 sin_m = blank_sin; 268 sin->sin_addr.s_addr = inet_addr(host); 269 if (sin->sin_addr.s_addr == -1) { 270 if (!(hp = gethostbyname(host))) { 271 fprintf(stderr, "arp: %s: ", host); 272 herror((char *)NULL); 273 exit(1); 274 } 275 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 276 sizeof sin->sin_addr); 277 } 278 dump(sin->sin_addr.s_addr); 279 if (found_entry == 0) { 280 printf("%s (%s) -- no entry\n", 281 host, inet_ntoa(sin->sin_addr)); 282 exit(1); 283 } 284 } 285 286 /* 287 * Delete an arp entry 288 */ 289 delete(host, info) 290 char *host; 291 char *info; 292 { 293 struct hostent *hp; 294 register struct sockaddr_inarp *sin = &sin_m; 295 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 296 struct sockaddr_dl *sdl; 297 u_char *ea; 298 char *eaddr; 299 300 if (info && strncmp(info, "pro", 3) ) 301 export_only = 1; 302 getsocket(); 303 sin_m = blank_sin; 304 sin->sin_addr.s_addr = inet_addr(host); 305 if (sin->sin_addr.s_addr == -1) { 306 if (!(hp = gethostbyname(host))) { 307 fprintf(stderr, "arp: %s: ", host); 308 herror((char *)NULL); 309 return (1); 310 } 311 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 312 sizeof sin->sin_addr); 313 } 314 tryagain: 315 if (rtmsg(RTM_GET) < 0) { 316 perror(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 fprintf(stderr, "delete: can't locate %s\n",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 printf("cannot locate %s\n", host); 340 return (1); 341 } 342 if (rtmsg(RTM_DELETE) == 0) 343 printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 344 } 345 346 /* 347 * Dump the entire arp table 348 */ 349 dump(addr) 350 u_long addr; 351 { 352 int mib[6]; 353 size_t needed; 354 char *host, *malloc(), *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 quit("route-sysctl-estimate"); 369 if ((buf = malloc(needed)) == NULL) 370 quit("malloc"); 371 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 372 quit("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 printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 396 if (sdl->sdl_alen) 397 ether_print(LLADDR(sdl)); 398 else 399 printf("(incomplete)"); 400 if (rtm->rtm_rmx.rmx_expire == 0) 401 printf(" permanent"); 402 if (sin->sin_other & SIN_PROXY) 403 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 printf(" published"); 409 if (sin->sin_len != 8) 410 printf("(wierd)"); 411 } 412 printf("\n"); 413 } 414 } 415 416 ether_print(cp) 417 u_char *cp; 418 { 419 printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]); 420 } 421 422 ether_aton(a, n) 423 char *a; 424 u_char *n; 425 { 426 int i, o[6]; 427 428 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], 429 &o[3], &o[4], &o[5]); 430 if (i != 6) { 431 fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a); 432 return (1); 433 } 434 for (i=0; i<6; i++) 435 n[i] = o[i]; 436 return (0); 437 } 438 439 usage() 440 { 441 printf("usage: arp hostname\n"); 442 printf(" arp -a [kernel] [kernel_memory]\n"); 443 printf(" arp -d hostname\n"); 444 printf(" arp -s hostname ether_addr [temp] [pub]\n"); 445 printf(" arp -f filename\n"); 446 exit(1); 447 } 448 449 rtmsg(cmd) 450 { 451 static int seq; 452 int rlen; 453 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 454 register char *cp = m_rtmsg.m_space; 455 register int l; 456 457 errno = 0; 458 if (cmd == RTM_DELETE) 459 goto doit; 460 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 461 rtm->rtm_flags = flags; 462 rtm->rtm_version = RTM_VERSION; 463 464 switch (cmd) { 465 default: 466 fprintf(stderr, "arp: internal wrong cmd\n"); 467 exit(1); 468 case RTM_ADD: 469 rtm->rtm_addrs |= RTA_GATEWAY; 470 rtm->rtm_rmx.rmx_expire = expire_time; 471 rtm->rtm_inits = RTV_EXPIRE; 472 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 473 sin_m.sin_other = 0; 474 if (doing_proxy) { 475 if (export_only) 476 sin_m.sin_other = SIN_PROXY; 477 else { 478 rtm->rtm_addrs |= RTA_NETMASK; 479 rtm->rtm_flags &= ~RTF_HOST; 480 } 481 } 482 /* FALLTHROUGH */ 483 case RTM_GET: 484 rtm->rtm_addrs |= RTA_DST; 485 } 486 #define NEXTADDR(w, s) \ 487 if (rtm->rtm_addrs & (w)) { \ 488 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 489 490 NEXTADDR(RTA_DST, sin_m); 491 NEXTADDR(RTA_GATEWAY, sdl_m); 492 NEXTADDR(RTA_NETMASK, so_mask); 493 494 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 495 doit: 496 l = rtm->rtm_msglen; 497 rtm->rtm_seq = ++seq; 498 rtm->rtm_type = cmd; 499 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 500 if (errno != ESRCH || cmd != RTM_DELETE) { 501 perror("writing to routing socket"); 502 return (-1); 503 } 504 } 505 do { 506 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 507 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 508 if (l < 0) 509 (void) fprintf(stderr, "arp: read from routing socket: %s\n", 510 strerror(errno)); 511 return (0); 512 } 513 514 quit(msg) 515 char *msg; 516 { 517 fprintf(stderr, "%s\n", msg); 518 exit(1); 519 } 520
Indexes created Tue Sep 30 20:09:53 GMT 2025