arp.c revision 1.14
1 /* $NetBSD: arp.c,v 1.14 1997/01/18 02:12:13 mikel 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 1.14 1997/01/18 02:12:13 mikel 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 void ether_print __P((const u_char *)); 79 int file __P((char *)); 80 void get __P((const char *)); 81 int getinetaddr __P((const char *, struct in_addr *)); 82 void getsocket __P((void)); 83 int rtmsg __P((int)); 84 int set __P((int, char **)); 85 void usage __P((void)); 86 87 static int pid; 88 static int nflag; 89 static int s = -1; 90 91 int 92 main(argc, argv) 93 int argc; 94 char **argv; 95 { 96 int ch; 97 98 pid = getpid(); 99 while ((ch = getopt(argc, argv, "andsf")) != EOF) 100 switch((char)ch) { 101 case 'a': 102 dump(0); 103 return (0); 104 case 'd': 105 if (argc < 3 || argc > 4) 106 usage(); 107 (void)delete(argv[2], argv[3]); 108 return (0); 109 case 'n': 110 nflag = 1; 111 break; 112 case 's': 113 if (argc < 4 || argc > 7) 114 usage(); 115 return (set(argc-2, &argv[2]) ? 1 : 0); 116 case 'f': 117 if (argc != 3) 118 usage(); 119 return (file(argv[2])); 120 case '?': 121 default: 122 usage(); 123 } 124 if (argc == 2 || (argc == 3 && nflag)) 125 get(argv[argc - 1]); 126 else 127 usage(); 128 return (0); 129 } 130 131 /* 132 * Process a file to set standard arp entries 133 */ 134 int 135 file(name) 136 char *name; 137 { 138 char line[100], arg[5][50], *args[5]; 139 int i, retval; 140 FILE *fp; 141 142 if ((fp = fopen(name, "r")) == NULL) 143 err(1, "cannot open %s", name); 144 args[0] = &arg[0][0]; 145 args[1] = &arg[1][0]; 146 args[2] = &arg[2][0]; 147 args[3] = &arg[3][0]; 148 args[4] = &arg[4][0]; 149 retval = 0; 150 while (fgets(line, 100, fp) != NULL) { 151 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 152 arg[3], arg[4]); 153 if (i < 2) { 154 warnx("bad line: %s", line); 155 retval = 1; 156 continue; 157 } 158 if (set(i, args)) 159 retval = 1; 160 } 161 fclose(fp); 162 return (retval); 163 } 164 165 void 166 getsocket() 167 { 168 if (s >= 0) 169 return; 170 s = socket(PF_ROUTE, SOCK_RAW, 0); 171 if (s < 0) 172 err(1, "socket"); 173 } 174 175 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 176 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 177 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 178 int expire_time, flags, export_only, doing_proxy, found_entry; 179 struct { 180 struct rt_msghdr m_rtm; 181 char m_space[512]; 182 } m_rtmsg; 183 184 /* 185 * Set an individual arp entry 186 */ 187 int 188 set(argc, argv) 189 int argc; 190 char **argv; 191 { 192 register struct sockaddr_inarp *sin; 193 register struct sockaddr_dl *sdl; 194 register struct rt_msghdr *rtm; 195 struct ether_addr *ea; 196 char *host = argv[0], *eaddr; 197 198 sin = &sin_m; 199 rtm = &(m_rtmsg.m_rtm); 200 eaddr = argv[1]; 201 202 getsocket(); 203 argc -= 2; 204 argv += 2; 205 sdl_m = blank_sdl; /* struct copy */ 206 sin_m = blank_sin; /* struct copy */ 207 if (getinetaddr(host, &sin->sin_addr) == -1) 208 return (1); 209 ea = ether_aton(eaddr); 210 if (ea != NULL) { 211 (void)memcpy(LLADDR(&sdl_m), ea, sizeof(struct ether_addr)); 212 sdl_m.sdl_alen = sizeof(struct ether_addr); 213 } 214 else 215 warnx("invalid Ethernet address '%s'", eaddr); 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 (void)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 (void)printf( 228 "%s: Sending trailers is no longer supported\n", 229 host); 230 } 231 argv++; 232 } 233 tryagain: 234 if (rtmsg(RTM_GET) < 0) { 235 warn("%s", host); 236 return (1); 237 } 238 sin = (struct sockaddr_inarp *)(rtm + 1); 239 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 240 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 241 if (sdl->sdl_family == AF_LINK && 242 (rtm->rtm_flags & RTF_LLINFO) && 243 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 244 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 245 case IFT_ISO88024: case IFT_ISO88025: 246 goto overwrite; 247 } 248 if (doing_proxy == 0) { 249 (void)printf("set: can only proxy for %s\n", host); 250 return (1); 251 } 252 if (sin_m.sin_other & SIN_PROXY) { 253 (void)printf( 254 "set: proxy entry exists for non 802 device\n"); 255 return (1); 256 } 257 sin_m.sin_other = SIN_PROXY; 258 export_only = 1; 259 goto tryagain; 260 } 261 overwrite: 262 if (sdl->sdl_family != AF_LINK) { 263 (void)printf("cannot intuit interface index and type for %s\n", 264 host); 265 return (1); 266 } 267 sdl_m.sdl_type = sdl->sdl_type; 268 sdl_m.sdl_index = sdl->sdl_index; 269 return (rtmsg(RTM_ADD)); 270 } 271 272 /* 273 * Display an individual arp entry 274 */ 275 void 276 get(host) 277 const char *host; 278 { 279 struct sockaddr_inarp *sin; 280 u_char *ea; 281 282 sin = &sin_m; 283 sin_m = blank_sin; /* struct copy */ 284 if (getinetaddr(host, &sin->sin_addr) == -1) 285 exit(1); 286 dump(sin->sin_addr.s_addr); 287 if (found_entry == 0) { 288 (void)printf("%s (%s) -- no entry\n", host, 289 inet_ntoa(sin->sin_addr)); 290 exit(1); 291 } 292 } 293 294 /* 295 * Delete an arp entry 296 */ 297 int 298 delete(host, info) 299 const char *host; 300 const char *info; 301 { 302 register struct sockaddr_inarp *sin; 303 register struct rt_msghdr *rtm; 304 struct sockaddr_dl *sdl; 305 u_char *ea; 306 char *eaddr; 307 308 sin = &sin_m; 309 rtm = &m_rtmsg.m_rtm; 310 311 if (info && strncmp(info, "pro", 3) ) 312 export_only = 1; 313 getsocket(); 314 sin_m = blank_sin; /* struct copy */ 315 if (getinetaddr(host, &sin->sin_addr) == -1) 316 return (1); 317 tryagain: 318 if (rtmsg(RTM_GET) < 0) { 319 warn("%s", host); 320 return (1); 321 } 322 sin = (struct sockaddr_inarp *)(rtm + 1); 323 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 324 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 325 if (sdl->sdl_family == AF_LINK && 326 (rtm->rtm_flags & RTF_LLINFO) && 327 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 328 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 329 case IFT_ISO88024: case IFT_ISO88025: 330 goto delete; 331 } 332 } 333 if (sin_m.sin_other & SIN_PROXY) { 334 warnx("delete: can't locate %s", host); 335 return (1); 336 } else { 337 sin_m.sin_other = SIN_PROXY; 338 goto tryagain; 339 } 340 delete: 341 if (sdl->sdl_family != AF_LINK) { 342 (void)printf("cannot locate %s\n", host); 343 return (1); 344 } 345 if (rtmsg(RTM_DELETE)) 346 return (1); 347 (void)printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 348 return (0); 349 } 350 351 /* 352 * Dump the entire arp table 353 */ 354 void 355 dump(addr) 356 u_long addr; 357 { 358 int mib[6]; 359 size_t needed; 360 char *host, *lim, *buf, *next; 361 struct rt_msghdr *rtm; 362 struct sockaddr_inarp *sin; 363 struct sockaddr_dl *sdl; 364 extern int h_errno; 365 struct hostent *hp; 366 367 mib[0] = CTL_NET; 368 mib[1] = PF_ROUTE; 369 mib[2] = 0; 370 mib[3] = AF_INET; 371 mib[4] = NET_RT_FLAGS; 372 mib[5] = RTF_LLINFO; 373 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 374 err(1, "route-sysctl-estimate"); 375 if ((buf = malloc(needed)) == NULL) 376 err(1, "malloc"); 377 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 378 err(1, "actual retrieval of routing table"); 379 lim = buf + needed; 380 for (next = buf; next < lim; next += rtm->rtm_msglen) { 381 rtm = (struct rt_msghdr *)next; 382 sin = (struct sockaddr_inarp *)(rtm + 1); 383 sdl = (struct sockaddr_dl *)(sin + 1); 384 if (addr) { 385 if (addr != sin->sin_addr.s_addr) 386 continue; 387 found_entry = 1; 388 } 389 if (nflag == 0) 390 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 391 sizeof sin->sin_addr, AF_INET); 392 else 393 hp = 0; 394 if (hp) 395 host = hp->h_name; 396 else { 397 host = "?"; 398 if (h_errno == TRY_AGAIN) 399 nflag = 1; 400 } 401 (void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 402 if (sdl->sdl_alen) 403 ether_print(LLADDR(sdl)); 404 else 405 (void)printf("(incomplete)"); 406 if (rtm->rtm_rmx.rmx_expire == 0) 407 (void)printf(" permanent"); 408 if (sin->sin_other & SIN_PROXY) 409 (void)printf(" published (proxy only)"); 410 if (rtm->rtm_addrs & RTA_NETMASK) { 411 sin = (struct sockaddr_inarp *) 412 (sdl->sdl_len + (char *)sdl); 413 if (sin->sin_addr.s_addr == 0xffffffff) 414 (void)printf(" published"); 415 if (sin->sin_len != 8) 416 (void)printf("(wierd)"); 417 } 418 (void)printf("\n"); 419 } 420 } 421 422 void 423 ether_print(cp) 424 const u_char *cp; 425 { 426 (void)printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], 427 cp[5]); 428 } 429 430 void 431 usage() 432 { 433 (void)fprintf(stderr, "usage: arp [-n] hostname\n"); 434 (void)fprintf(stderr, "usage: arp [-n] -a\n"); 435 (void)fprintf(stderr, "usage: arp -d hostname\n"); 436 (void)fprintf(stderr, 437 "usage: arp -s hostname ether_addr [temp] [pub]\n"); 438 (void)fprintf(stderr, "usage: arp -f filename\n"); 439 exit(1); 440 } 441 442 int 443 rtmsg(cmd) 444 int cmd; 445 { 446 static int seq; 447 int rlen; 448 register struct rt_msghdr *rtm; 449 register char *cp; 450 register int l; 451 452 rtm = &m_rtmsg.m_rtm; 453 cp = m_rtmsg.m_space; 454 errno = 0; 455 456 if (cmd == RTM_DELETE) 457 goto doit; 458 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 459 rtm->rtm_flags = flags; 460 rtm->rtm_version = RTM_VERSION; 461 462 switch (cmd) { 463 default: 464 errx(1, "internal wrong cmd"); 465 /*NOTREACHED*/ 466 case RTM_ADD: 467 rtm->rtm_addrs |= RTA_GATEWAY; 468 rtm->rtm_rmx.rmx_expire = expire_time; 469 rtm->rtm_inits = RTV_EXPIRE; 470 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 471 sin_m.sin_other = 0; 472 if (doing_proxy) { 473 if (export_only) 474 sin_m.sin_other = SIN_PROXY; 475 else { 476 rtm->rtm_addrs |= RTA_NETMASK; 477 rtm->rtm_flags &= ~RTF_HOST; 478 } 479 } 480 /* FALLTHROUGH */ 481 case RTM_GET: 482 rtm->rtm_addrs |= RTA_DST; 483 } 484 #define NEXTADDR(w, s) \ 485 if (rtm->rtm_addrs & (w)) { \ 486 (void)memcpy(cp, &s, sizeof(s)); cp += sizeof(s);} 487 488 NEXTADDR(RTA_DST, sin_m); 489 NEXTADDR(RTA_GATEWAY, sdl_m); 490 NEXTADDR(RTA_NETMASK, so_mask); 491 492 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 493 doit: 494 l = rtm->rtm_msglen; 495 rtm->rtm_seq = ++seq; 496 rtm->rtm_type = cmd; 497 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 498 if (errno != ESRCH || cmd != RTM_DELETE) { 499 warn("writing to routing socket"); 500 return (-1); 501 } 502 } 503 do { 504 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 505 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 506 if (l < 0) 507 warn("read from routing socket"); 508 return (0); 509 } 510 511 int 512 getinetaddr(host, inap) 513 const char *host; 514 struct in_addr *inap; 515 { 516 struct hostent *hp; 517 u_long addr; 518 519 if (inet_aton(host, inap) == 1) 520 return (0); 521 if ((hp = gethostbyname(host)) == NULL) { 522 warnx("%s: %s\n", host, hstrerror(h_errno)); 523 return (-1); 524 } 525 (void)memcpy(inap, hp->h_addr, sizeof(*inap)); 526 return (0); 527 } 528
Indexes created Tue Sep 30 20:09:53 GMT 2025