arp.c revision 1.5
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 1.5 1994/05/13 08:09:22 mycroft 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, "ands")) != 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 '?': 105 default: 106 usage(); 107 } 108 if (argc != 2) 109 usage(); 110 get(argv[1]); 111 exit(0); 112 } 113 114 /* 115 * Process a file to set standard arp entries 116 */ 117 file(name) 118 char *name; 119 { 120 FILE *fp; 121 int i, retval; 122 char line[100], arg[5][50], *args[5]; 123 124 if ((fp = fopen(name, "r")) == NULL) { 125 fprintf(stderr, "arp: cannot open %s\n", name); 126 exit(1); 127 } 128 args[0] = &arg[0][0]; 129 args[1] = &arg[1][0]; 130 args[2] = &arg[2][0]; 131 args[3] = &arg[3][0]; 132 args[4] = &arg[4][0]; 133 retval = 0; 134 while(fgets(line, 100, fp) != NULL) { 135 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 136 arg[3], arg[4]); 137 if (i < 2) { 138 fprintf(stderr, "arp: bad line: %s\n", line); 139 retval = 1; 140 continue; 141 } 142 if (set(i, args)) 143 retval = 1; 144 } 145 fclose(fp); 146 return (retval); 147 } 148 149 getsocket() { 150 if (s < 0) { 151 s = socket(PF_ROUTE, SOCK_RAW, 0); 152 if (s < 0) { 153 perror("arp: socket"); 154 exit(1); 155 } 156 } 157 } 158 159 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 160 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 161 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 162 int expire_time, flags, export_only, doing_proxy, found_entry; 163 struct { 164 struct rt_msghdr m_rtm; 165 char m_space[512]; 166 } m_rtmsg; 167 168 /* 169 * Set an individual arp entry 170 */ 171 set(argc, argv) 172 int argc; 173 char **argv; 174 { 175 struct hostent *hp; 176 register struct sockaddr_inarp *sin = &sin_m; 177 register struct sockaddr_dl *sdl; 178 register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 179 u_char *ea; 180 char *host = argv[0], *eaddr = argv[1]; 181 182 getsocket(); 183 argc -= 2; 184 argv += 2; 185 sdl_m = blank_sdl; 186 sin_m = blank_sin; 187 sin->sin_addr.s_addr = inet_addr(host); 188 if (sin->sin_addr.s_addr == -1) { 189 if (!(hp = gethostbyname(host))) { 190 fprintf(stderr, "arp: %s: ", host); 191 herror((char *)NULL); 192 return (1); 193 } 194 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 195 sizeof sin->sin_addr); 196 } 197 ea = (u_char *)LLADDR(&sdl_m); 198 if (ether_aton(eaddr, ea) == 0) 199 sdl_m.sdl_alen = 6; 200 doing_proxy = flags = export_only = expire_time = 0; 201 while (argc-- > 0) { 202 if (strncmp(argv[0], "temp", 4) == 0) { 203 struct timeval time; 204 gettimeofday(&time, 0); 205 expire_time = time.tv_sec + 20 * 60; 206 } 207 else if (strncmp(argv[0], "pub", 3) == 0) { 208 flags |= RTF_ANNOUNCE; 209 doing_proxy = SIN_PROXY; 210 } else if (strncmp(argv[0], "trail", 5) == 0) { 211 printf("%s: Sending trailers is no longer supported\n", 212 host); 213 } 214 argv++; 215 } 216 tryagain: 217 if (rtmsg(RTM_GET) < 0) { 218 perror(host); 219 return (1); 220 } 221 sin = (struct sockaddr_inarp *)(rtm + 1); 222 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 223 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 224 if (sdl->sdl_family == AF_LINK && 225 (rtm->rtm_flags & RTF_LLINFO) && 226 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 227 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 228 case IFT_ISO88024: case IFT_ISO88025: 229 goto overwrite; 230 } 231 if (doing_proxy == 0) { 232 printf("set: can only proxy for %s\n", host); 233 return (1); 234 } 235 if (sin_m.sin_other & SIN_PROXY) { 236 printf("set: proxy entry exists for non 802 device\n"); 237 return(1); 238 } 239 sin_m.sin_other = SIN_PROXY; 240 export_only = 1; 241 goto tryagain; 242 } 243 overwrite: 244 if (sdl->sdl_family != AF_LINK) { 245 printf("cannot intuit interface index and type for %s\n", host); 246 return (1); 247 } 248 sdl_m.sdl_type = sdl->sdl_type; 249 sdl_m.sdl_index = sdl->sdl_index; 250 return (rtmsg(RTM_ADD)); 251 } 252 253 /* 254 * Display an individual arp entry 255 */ 256 get(host) 257 char *host; 258 { 259 struct hostent *hp; 260 struct sockaddr_inarp *sin = &sin_m; 261 u_char *ea; 262 263 sin_m = blank_sin; 264 sin->sin_addr.s_addr = inet_addr(host); 265 if (sin->sin_addr.s_addr == -1) { 266 if (!(hp = gethostbyname(host))) { 267 fprintf(stderr, "arp: %s: ", host); 268 herror((char *)NULL); 269 exit(1); 270 } 271 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 272 sizeof sin->sin_addr); 273 } 274 dump(sin->sin_addr.s_addr); 275 if (found_entry == 0) { 276 printf("%s (%s) -- no entry\n", 277 host, inet_ntoa(sin->sin_addr)); 278 exit(1); 279 } 280 } 281 282 /* 283 * Delete an arp entry 284 */ 285 delete(host, info) 286 char *host; 287 char *info; 288 { 289 struct hostent *hp; 290 register struct sockaddr_inarp *sin = &sin_m; 291 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 292 struct sockaddr_dl *sdl; 293 u_char *ea; 294 char *eaddr; 295 296 if (info && strncmp(info, "pro", 3) ) 297 export_only = 1; 298 getsocket(); 299 sin_m = blank_sin; 300 sin->sin_addr.s_addr = inet_addr(host); 301 if (sin->sin_addr.s_addr == -1) { 302 if (!(hp = gethostbyname(host))) { 303 fprintf(stderr, "arp: %s: ", host); 304 herror((char *)NULL); 305 return (1); 306 } 307 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 308 sizeof sin->sin_addr); 309 } 310 tryagain: 311 if (rtmsg(RTM_GET) < 0) { 312 perror(host); 313 return (1); 314 } 315 sin = (struct sockaddr_inarp *)(rtm + 1); 316 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 317 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 318 if (sdl->sdl_family == AF_LINK && 319 (rtm->rtm_flags & RTF_LLINFO) && 320 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 321 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 322 case IFT_ISO88024: case IFT_ISO88025: 323 goto delete; 324 } 325 } 326 if (sin_m.sin_other & SIN_PROXY) { 327 fprintf(stderr, "delete: can't locate %s\n",host); 328 return (1); 329 } else { 330 sin_m.sin_other = SIN_PROXY; 331 goto tryagain; 332 } 333 delete: 334 if (sdl->sdl_family != AF_LINK) { 335 printf("cannot locate %s\n", host); 336 return (1); 337 } 338 if (rtmsg(RTM_DELETE) == 0) 339 printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 340 } 341 342 /* 343 * Dump the entire arp table 344 */ 345 dump(addr) 346 u_long addr; 347 { 348 int mib[6]; 349 size_t needed; 350 char *host, *malloc(), *lim, *buf, *next; 351 struct rt_msghdr *rtm; 352 struct sockaddr_inarp *sin; 353 struct sockaddr_dl *sdl; 354 extern int h_errno; 355 struct hostent *hp; 356 357 mib[0] = CTL_NET; 358 mib[1] = PF_ROUTE; 359 mib[2] = 0; 360 mib[3] = AF_INET; 361 mib[4] = NET_RT_FLAGS; 362 mib[5] = RTF_LLINFO; 363 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 364 quit("route-sysctl-estimate"); 365 if ((buf = malloc(needed)) == NULL) 366 quit("malloc"); 367 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 368 quit("actual retrieval of routing table"); 369 lim = buf + needed; 370 for (next = buf; next < lim; next += rtm->rtm_msglen) { 371 rtm = (struct rt_msghdr *)next; 372 sin = (struct sockaddr_inarp *)(rtm + 1); 373 sdl = (struct sockaddr_dl *)(sin + 1); 374 if (addr) { 375 if (addr != sin->sin_addr.s_addr) 376 continue; 377 found_entry = 1; 378 } 379 if (nflag == 0) 380 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 381 sizeof sin->sin_addr, AF_INET); 382 else 383 hp = 0; 384 if (hp) 385 host = hp->h_name; 386 else { 387 host = "?"; 388 if (h_errno == TRY_AGAIN) 389 nflag = 1; 390 } 391 printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 392 if (sdl->sdl_alen) 393 ether_print(LLADDR(sdl)); 394 else 395 printf("(incomplete)"); 396 if (rtm->rtm_rmx.rmx_expire == 0) 397 printf(" permanent"); 398 if (sin->sin_other & SIN_PROXY) 399 printf(" published (proxy only)"); 400 if (rtm->rtm_addrs & RTA_NETMASK) { 401 sin = (struct sockaddr_inarp *) 402 (sdl->sdl_len + (char *)sdl); 403 if (sin->sin_addr.s_addr == 0xffffffff) 404 printf(" published"); 405 if (sin->sin_len != 8) 406 printf("(wierd)"); 407 } 408 printf("\n"); 409 } 410 } 411 412 ether_print(cp) 413 u_char *cp; 414 { 415 printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]); 416 } 417 418 ether_aton(a, n) 419 char *a; 420 u_char *n; 421 { 422 int i, o[6]; 423 424 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], 425 &o[3], &o[4], &o[5]); 426 if (i != 6) { 427 fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a); 428 return (1); 429 } 430 for (i=0; i<6; i++) 431 n[i] = o[i]; 432 return (0); 433 } 434 435 usage() 436 { 437 printf("usage: arp hostname\n"); 438 printf(" arp -a [kernel] [kernel_memory]\n"); 439 printf(" arp -d hostname\n"); 440 printf(" arp -s hostname ether_addr [temp] [pub]\n"); 441 printf(" arp -f filename\n"); 442 exit(1); 443 } 444 445 rtmsg(cmd) 446 { 447 static int seq; 448 int rlen; 449 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 450 register char *cp = m_rtmsg.m_space; 451 register int l; 452 453 errno = 0; 454 if (cmd == RTM_DELETE) 455 goto doit; 456 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 457 rtm->rtm_flags = flags; 458 rtm->rtm_version = RTM_VERSION; 459 460 switch (cmd) { 461 default: 462 fprintf(stderr, "arp: internal wrong cmd\n"); 463 exit(1); 464 case RTM_ADD: 465 rtm->rtm_addrs |= RTA_GATEWAY; 466 rtm->rtm_rmx.rmx_expire = expire_time; 467 rtm->rtm_inits = RTV_EXPIRE; 468 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 469 sin_m.sin_other = 0; 470 if (doing_proxy) { 471 if (export_only) 472 sin_m.sin_other = SIN_PROXY; 473 else { 474 rtm->rtm_addrs |= RTA_NETMASK; 475 rtm->rtm_flags &= ~RTF_HOST; 476 } 477 } 478 /* FALLTHROUGH */ 479 case RTM_GET: 480 rtm->rtm_addrs |= RTA_DST; 481 } 482 #define NEXTADDR(w, s) \ 483 if (rtm->rtm_addrs & (w)) { \ 484 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 485 486 NEXTADDR(RTA_DST, sin_m); 487 NEXTADDR(RTA_GATEWAY, sdl_m); 488 NEXTADDR(RTA_NETMASK, so_mask); 489 490 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 491 doit: 492 l = rtm->rtm_msglen; 493 rtm->rtm_seq = ++seq; 494 rtm->rtm_type = cmd; 495 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 496 if (errno != ESRCH || cmd != RTM_DELETE) { 497 perror("writing to routing socket"); 498 return (-1); 499 } 500 } 501 do { 502 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 503 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 504 if (l < 0) 505 (void) fprintf(stderr, "arp: read from routing socket: %s\n", 506 strerror(errno)); 507 return (0); 508 } 509 510 quit(msg) 511 char *msg; 512 { 513 fprintf(stderr, "%s\n", msg); 514 exit(1); 515 } 516
Indexes created Tue Sep 30 20:09:53 GMT 2025