arp.c revision 1.1.1.3
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[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; 45 #endif /* not lint */ 46 47 /* 48 * arp - display, set, and delete arp table entries 49 */ 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 62 #include <netinet/in.h> 63 #include <netinet/if_ether.h> 64 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((char *, char *)); 82 void dump __P((u_long)); 83 int ether_aton __P((char *, u_char *)); 84 void ether_print __P((u_char *)); 85 int file __P((char *)); 86 void get __P((char *)); 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 99 pid = getpid(); 100 while ((ch = getopt(argc, argv, "ands")) != EOF) 101 switch((char)ch) { 102 case 'a': 103 dump(0); 104 exit(0); 105 case 'd': 106 if (argc < 3 || argc > 4) 107 usage(); 108 delete(argv[2], argv[3]); 109 exit(0); 110 case 'n': 111 nflag = 1; 112 continue; 113 case 's': 114 if (argc < 4 || argc > 7) 115 usage(); 116 exit(set(argc-2, &argv[2]) ? 1 : 0); 117 case '?': 118 default: 119 usage(); 120 } 121 if (argc != 2) 122 usage(); 123 get(argv[1]); 124 return (0); 125 } 126 127 /* 128 * Process a file to set standard arp entries 129 */ 130 int 131 file(name) 132 char *name; 133 { 134 FILE *fp; 135 int i, retval; 136 char line[100], arg[5][50], *args[5]; 137 138 if ((fp = fopen(name, "r")) == NULL) { 139 fprintf(stderr, "arp: cannot open %s\n", name); 140 exit(1); 141 } 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 fprintf(stderr, "arp: bad line: %s\n", 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 if (s < 0) { 166 s = socket(PF_ROUTE, SOCK_RAW, 0); 167 if (s < 0) { 168 perror("arp: socket"); 169 exit(1); 170 } 171 } 172 } 173 174 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 175 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 176 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 177 int expire_time, flags, export_only, doing_proxy, found_entry; 178 struct { 179 struct rt_msghdr m_rtm; 180 char m_space[512]; 181 } m_rtmsg; 182 183 /* 184 * Set an individual arp entry 185 */ 186 int 187 set(argc, argv) 188 int argc; 189 char **argv; 190 { 191 struct hostent *hp; 192 register struct sockaddr_inarp *sin = &sin_m; 193 register struct sockaddr_dl *sdl; 194 register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 195 u_char *ea; 196 char *host = argv[0], *eaddr = argv[1]; 197 198 getsocket(); 199 argc -= 2; 200 argv += 2; 201 sdl_m = blank_sdl; 202 sin_m = blank_sin; 203 sin->sin_addr.s_addr = inet_addr(host); 204 if (sin->sin_addr.s_addr == -1) { 205 if (!(hp = gethostbyname(host))) { 206 fprintf(stderr, "arp: %s: ", host); 207 herror((char *)NULL); 208 return (1); 209 } 210 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 211 sizeof sin->sin_addr); 212 } 213 ea = (u_char *)LLADDR(&sdl_m); 214 if (ether_aton(eaddr, ea) == 0) 215 sdl_m.sdl_alen = 6; 216 doing_proxy = flags = export_only = expire_time = 0; 217 while (argc-- > 0) { 218 if (strncmp(argv[0], "temp", 4) == 0) { 219 struct timeval time; 220 gettimeofday(&time, 0); 221 expire_time = time.tv_sec + 20 * 60; 222 } 223 else if (strncmp(argv[0], "pub", 3) == 0) { 224 flags |= RTF_ANNOUNCE; 225 doing_proxy = SIN_PROXY; 226 } else if (strncmp(argv[0], "trail", 5) == 0) { 227 printf("%s: Sending trailers is no longer supported\n", 228 host); 229 } 230 argv++; 231 } 232 tryagain: 233 if (rtmsg(RTM_GET) < 0) { 234 perror(host); 235 return (1); 236 } 237 sin = (struct sockaddr_inarp *)(rtm + 1); 238 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 239 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 240 if (sdl->sdl_family == AF_LINK && 241 (rtm->rtm_flags & RTF_LLINFO) && 242 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 243 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 244 case IFT_ISO88024: case IFT_ISO88025: 245 goto overwrite; 246 } 247 if (doing_proxy == 0) { 248 printf("set: can only proxy for %s\n", host); 249 return (1); 250 } 251 if (sin_m.sin_other & SIN_PROXY) { 252 printf("set: proxy entry exists for non 802 device\n"); 253 return(1); 254 } 255 sin_m.sin_other = SIN_PROXY; 256 export_only = 1; 257 goto tryagain; 258 } 259 overwrite: 260 if (sdl->sdl_family != AF_LINK) { 261 printf("cannot intuit interface index and type for %s\n", 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 char *host; 275 { 276 struct hostent *hp; 277 struct sockaddr_inarp *sin = &sin_m; 278 279 sin_m = blank_sin; 280 sin->sin_addr.s_addr = inet_addr(host); 281 if (sin->sin_addr.s_addr == -1) { 282 if (!(hp = gethostbyname(host))) { 283 fprintf(stderr, "arp: %s: ", host); 284 herror((char *)NULL); 285 exit(1); 286 } 287 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 288 sizeof sin->sin_addr); 289 } 290 dump(sin->sin_addr.s_addr); 291 if (found_entry == 0) { 292 printf("%s (%s) -- no entry\n", 293 host, inet_ntoa(sin->sin_addr)); 294 exit(1); 295 } 296 } 297 298 /* 299 * Delete an arp entry 300 */ 301 int 302 delete(host, info) 303 char *host; 304 char *info; 305 { 306 struct hostent *hp; 307 register struct sockaddr_inarp *sin = &sin_m; 308 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 309 struct sockaddr_dl *sdl; 310 311 if (info && strncmp(info, "pro", 3) ) 312 export_only = 1; 313 getsocket(); 314 sin_m = blank_sin; 315 sin->sin_addr.s_addr = inet_addr(host); 316 if (sin->sin_addr.s_addr == -1) { 317 if (!(hp = gethostbyname(host))) { 318 fprintf(stderr, "arp: %s: ", host); 319 herror((char *)NULL); 320 return (1); 321 } 322 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 323 sizeof sin->sin_addr); 324 } 325 tryagain: 326 if (rtmsg(RTM_GET) < 0) { 327 perror(host); 328 return (1); 329 } 330 sin = (struct sockaddr_inarp *)(rtm + 1); 331 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 332 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 333 if (sdl->sdl_family == AF_LINK && 334 (rtm->rtm_flags & RTF_LLINFO) && 335 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 336 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 337 case IFT_ISO88024: case IFT_ISO88025: 338 goto delete; 339 } 340 } 341 if (sin_m.sin_other & SIN_PROXY) { 342 fprintf(stderr, "delete: can't locate %s\n",host); 343 return (1); 344 } else { 345 sin_m.sin_other = SIN_PROXY; 346 goto tryagain; 347 } 348 delete: 349 if (sdl->sdl_family != AF_LINK) { 350 printf("cannot locate %s\n", host); 351 return (1); 352 } 353 if (rtmsg(RTM_DELETE)) 354 return (1); 355 printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 356 return (0); 357 } 358 359 /* 360 * Dump the entire arp table 361 */ 362 void 363 dump(addr) 364 u_long addr; 365 { 366 int mib[6]; 367 size_t needed; 368 char *host, *lim, *buf, *next; 369 struct rt_msghdr *rtm; 370 struct sockaddr_inarp *sin; 371 struct sockaddr_dl *sdl; 372 extern int h_errno; 373 struct hostent *hp; 374 375 mib[0] = CTL_NET; 376 mib[1] = PF_ROUTE; 377 mib[2] = 0; 378 mib[3] = AF_INET; 379 mib[4] = NET_RT_FLAGS; 380 mib[5] = RTF_LLINFO; 381 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 382 err(1, "route-sysctl-estimate"); 383 if ((buf = malloc(needed)) == NULL) 384 err(1, "malloc"); 385 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 386 err(1, "actual retrieval of routing table"); 387 lim = buf + needed; 388 for (next = buf; next < lim; next += rtm->rtm_msglen) { 389 rtm = (struct rt_msghdr *)next; 390 sin = (struct sockaddr_inarp *)(rtm + 1); 391 sdl = (struct sockaddr_dl *)(sin + 1); 392 if (addr) { 393 if (addr != sin->sin_addr.s_addr) 394 continue; 395 found_entry = 1; 396 } 397 if (nflag == 0) 398 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 399 sizeof sin->sin_addr, AF_INET); 400 else 401 hp = 0; 402 if (hp) 403 host = hp->h_name; 404 else { 405 host = "?"; 406 if (h_errno == TRY_AGAIN) 407 nflag = 1; 408 } 409 printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 410 if (sdl->sdl_alen) 411 ether_print((u_char *)LLADDR(sdl)); 412 else 413 printf("(incomplete)"); 414 if (rtm->rtm_rmx.rmx_expire == 0) 415 printf(" permanent"); 416 if (sin->sin_other & SIN_PROXY) 417 printf(" published (proxy only)"); 418 if (rtm->rtm_addrs & RTA_NETMASK) { 419 sin = (struct sockaddr_inarp *) 420 (sdl->sdl_len + (char *)sdl); 421 if (sin->sin_addr.s_addr == 0xffffffff) 422 printf(" published"); 423 if (sin->sin_len != 8) 424 printf("(wierd)"); 425 } 426 printf("\n"); 427 } 428 } 429 430 void 431 ether_print(cp) 432 u_char *cp; 433 { 434 printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]); 435 } 436 437 int 438 ether_aton(a, n) 439 char *a; 440 u_char *n; 441 { 442 int i, o[6]; 443 444 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], 445 &o[3], &o[4], &o[5]); 446 if (i != 6) { 447 fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a); 448 return (1); 449 } 450 for (i=0; i<6; i++) 451 n[i] = o[i]; 452 return (0); 453 } 454 455 void 456 usage() 457 { 458 printf("usage: arp hostname\n"); 459 printf(" arp -a [kernel] [kernel_memory]\n"); 460 printf(" arp -d hostname\n"); 461 printf(" arp -s hostname ether_addr [temp] [pub]\n"); 462 printf(" arp -f filename\n"); 463 exit(1); 464 } 465 466 int 467 rtmsg(cmd) 468 int cmd; 469 { 470 static int seq; 471 int rlen; 472 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 473 register char *cp = m_rtmsg.m_space; 474 register int l; 475 476 errno = 0; 477 if (cmd == RTM_DELETE) 478 goto doit; 479 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 480 rtm->rtm_flags = flags; 481 rtm->rtm_version = RTM_VERSION; 482 483 switch (cmd) { 484 default: 485 fprintf(stderr, "arp: internal wrong cmd\n"); 486 exit(1); 487 case RTM_ADD: 488 rtm->rtm_addrs |= RTA_GATEWAY; 489 rtm->rtm_rmx.rmx_expire = expire_time; 490 rtm->rtm_inits = RTV_EXPIRE; 491 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 492 sin_m.sin_other = 0; 493 if (doing_proxy) { 494 if (export_only) 495 sin_m.sin_other = SIN_PROXY; 496 else { 497 rtm->rtm_addrs |= RTA_NETMASK; 498 rtm->rtm_flags &= ~RTF_HOST; 499 } 500 } 501 /* FALLTHROUGH */ 502 case RTM_GET: 503 rtm->rtm_addrs |= RTA_DST; 504 } 505 #define NEXTADDR(w, s) \ 506 if (rtm->rtm_addrs & (w)) { \ 507 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 508 509 NEXTADDR(RTA_DST, sin_m); 510 NEXTADDR(RTA_GATEWAY, sdl_m); 511 NEXTADDR(RTA_NETMASK, so_mask); 512 513 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 514 doit: 515 l = rtm->rtm_msglen; 516 rtm->rtm_seq = ++seq; 517 rtm->rtm_type = cmd; 518 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 519 if (errno != ESRCH || cmd != RTM_DELETE) { 520 perror("writing to routing socket"); 521 return (-1); 522 } 523 } 524 do { 525 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 526 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 527 if (l < 0) 528 (void) fprintf(stderr, "arp: read from routing socket: %s\n", 529 strerror(errno)); 530 return (0); 531 } 532
Indexes created Tue Sep 30 20:09:53 GMT 2025