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 * %sccs.include.redist.c% 9 */ 10 11 #ifndef lint 12 static char copyright[] = 13 "@(#) Copyright (c) 1984, 1993\n\ 14 The Regents of the University of California. All rights reserved.\n"; 15 #endif /* not lint */ 16 17 #ifndef lint 18 static char sccsid[] = "@(#)arp.c 8.1 (Berkeley) 06/06/93"; 19 #endif /* not lint */ 20 21 /* 22 * arp - display, set, and delete arp table entries 23 */ 24 25 26 #include <sys/param.h> 27 #include <sys/file.h> 28 #include <sys/socket.h> 29 #include <sys/sysctl.h> 30 31 #include <net/if.h> 32 #include <net/if_dl.h> 33 #include <net/if_types.h> 34 #include <net/route.h> 35 36 #include <netinet/in.h> 37 #include <netinet/if_ether.h> 38 39 #include <arpa/inet.h> 40 41 #include <netdb.h> 42 #include <errno.h> 43 #include <nlist.h> 44 #include <stdio.h> 45 #include <paths.h> 46 47 extern int errno; 48 static int pid; 49 static int kflag; 50 static int nflag; 51 static int s = -1; 52 53 main(argc, argv) 54 int argc; 55 char **argv; 56 { 57 int ch; 58 59 pid = getpid(); 60 while ((ch = getopt(argc, argv, "ands")) != EOF) 61 switch((char)ch) { 62 case 'a': 63 dump(0); 64 exit(0); 65 case 'd': 66 if (argc < 3 || argc > 4) 67 usage(); 68 delete(argv[2], argv[3]); 69 exit(0); 70 case 'n': 71 nflag = 1; 72 continue; 73 case 's': 74 if (argc < 4 || argc > 7) 75 usage(); 76 exit(set(argc-2, &argv[2]) ? 1 : 0); 77 case '?': 78 default: 79 usage(); 80 } 81 if (argc != 2) 82 usage(); 83 get(argv[1]); 84 exit(0); 85 } 86 87 /* 88 * Process a file to set standard arp entries 89 */ 90 file(name) 91 char *name; 92 { 93 FILE *fp; 94 int i, retval; 95 char line[100], arg[5][50], *args[5]; 96 97 if ((fp = fopen(name, "r")) == NULL) { 98 fprintf(stderr, "arp: cannot open %s\n", name); 99 exit(1); 100 } 101 args[0] = &arg[0][0]; 102 args[1] = &arg[1][0]; 103 args[2] = &arg[2][0]; 104 args[3] = &arg[3][0]; 105 args[4] = &arg[4][0]; 106 retval = 0; 107 while(fgets(line, 100, fp) != NULL) { 108 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 109 arg[3], arg[4]); 110 if (i < 2) { 111 fprintf(stderr, "arp: bad line: %s\n", line); 112 retval = 1; 113 continue; 114 } 115 if (set(i, args)) 116 retval = 1; 117 } 118 fclose(fp); 119 return (retval); 120 } 121 122 getsocket() { 123 if (s < 0) { 124 s = socket(PF_ROUTE, SOCK_RAW, 0); 125 if (s < 0) { 126 perror("arp: socket"); 127 exit(1); 128 } 129 } 130 } 131 132 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 133 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 134 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 135 int expire_time, flags, export_only, doing_proxy, found_entry; 136 struct { 137 struct rt_msghdr m_rtm; 138 char m_space[512]; 139 } m_rtmsg; 140 141 /* 142 * Set an individual arp entry 143 */ 144 set(argc, argv) 145 int argc; 146 char **argv; 147 { 148 struct hostent *hp; 149 register struct sockaddr_inarp *sin = &sin_m; 150 register struct sockaddr_dl *sdl; 151 register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 152 u_char *ea; 153 char *host = argv[0], *eaddr = argv[1]; 154 155 getsocket(); 156 argc -= 2; 157 argv += 2; 158 sdl_m = blank_sdl; 159 sin_m = blank_sin; 160 sin->sin_addr.s_addr = inet_addr(host); 161 if (sin->sin_addr.s_addr == -1) { 162 if (!(hp = gethostbyname(host))) { 163 fprintf(stderr, "arp: %s: ", host); 164 herror((char *)NULL); 165 return (1); 166 } 167 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 168 sizeof sin->sin_addr); 169 } 170 ea = (u_char *)LLADDR(&sdl_m); 171 if (ether_aton(eaddr, ea) == 0) 172 sdl_m.sdl_alen = 6; 173 doing_proxy = flags = export_only = expire_time = 0; 174 while (argc-- > 0) { 175 if (strncmp(argv[0], "temp", 4) == 0) { 176 struct timeval time; 177 gettimeofday(&time, 0); 178 expire_time = time.tv_sec + 20 * 60; 179 } 180 else if (strncmp(argv[0], "pub", 3) == 0) { 181 flags |= RTF_ANNOUNCE; 182 doing_proxy = SIN_PROXY; 183 } else if (strncmp(argv[0], "trail", 5) == 0) { 184 printf("%s: Sending trailers is no longer supported\n", 185 host); 186 } 187 argv++; 188 } 189 tryagain: 190 if (rtmsg(RTM_GET) < 0) { 191 perror(host); 192 return (1); 193 } 194 sin = (struct sockaddr_inarp *)(rtm + 1); 195 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 196 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 197 if (sdl->sdl_family == AF_LINK && 198 (rtm->rtm_flags & RTF_LLINFO) && 199 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 200 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 201 case IFT_ISO88024: case IFT_ISO88025: 202 goto overwrite; 203 } 204 if (doing_proxy == 0) { 205 printf("set: can only proxy for %s\n", host); 206 return (1); 207 } 208 if (sin_m.sin_other & SIN_PROXY) { 209 printf("set: proxy entry exists for non 802 device\n"); 210 return(1); 211 } 212 sin_m.sin_other = SIN_PROXY; 213 export_only = 1; 214 goto tryagain; 215 } 216 overwrite: 217 if (sdl->sdl_family != AF_LINK) { 218 printf("cannot intuit interface index and type for %s\n", host); 219 return (1); 220 } 221 sdl_m.sdl_type = sdl->sdl_type; 222 sdl_m.sdl_index = sdl->sdl_index; 223 return (rtmsg(RTM_ADD)); 224 } 225 226 /* 227 * Display an individual arp entry 228 */ 229 get(host) 230 char *host; 231 { 232 struct hostent *hp; 233 struct sockaddr_inarp *sin = &sin_m; 234 u_char *ea; 235 236 sin_m = blank_sin; 237 sin->sin_addr.s_addr = inet_addr(host); 238 if (sin->sin_addr.s_addr == -1) { 239 if (!(hp = gethostbyname(host))) { 240 fprintf(stderr, "arp: %s: ", host); 241 herror((char *)NULL); 242 exit(1); 243 } 244 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 245 sizeof sin->sin_addr); 246 } 247 dump(sin->sin_addr.s_addr); 248 if (found_entry == 0) { 249 printf("%s (%s) -- no entry\n", 250 host, inet_ntoa(sin->sin_addr)); 251 exit(1); 252 } 253 } 254 255 /* 256 * Delete an arp entry 257 */ 258 delete(host, info) 259 char *host; 260 char *info; 261 { 262 struct hostent *hp; 263 register struct sockaddr_inarp *sin = &sin_m; 264 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 265 struct sockaddr_dl *sdl; 266 u_char *ea; 267 char *eaddr; 268 269 if (info && strncmp(info, "pro", 3) ) 270 export_only = 1; 271 getsocket(); 272 sin_m = blank_sin; 273 sin->sin_addr.s_addr = inet_addr(host); 274 if (sin->sin_addr.s_addr == -1) { 275 if (!(hp = gethostbyname(host))) { 276 fprintf(stderr, "arp: %s: ", host); 277 herror((char *)NULL); 278 return (1); 279 } 280 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 281 sizeof sin->sin_addr); 282 } 283 tryagain: 284 if (rtmsg(RTM_GET) < 0) { 285 perror(host); 286 return (1); 287 } 288 sin = (struct sockaddr_inarp *)(rtm + 1); 289 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 290 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 291 if (sdl->sdl_family == AF_LINK && 292 (rtm->rtm_flags & RTF_LLINFO) && 293 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 294 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 295 case IFT_ISO88024: case IFT_ISO88025: 296 goto delete; 297 } 298 } 299 if (sin_m.sin_other & SIN_PROXY) { 300 fprintf(stderr, "delete: can't locate %s\n",host); 301 return (1); 302 } else { 303 sin_m.sin_other = SIN_PROXY; 304 goto tryagain; 305 } 306 delete: 307 if (sdl->sdl_family != AF_LINK) { 308 printf("cannot locate %s\n", host); 309 return (1); 310 } 311 if (rtmsg(RTM_DELETE) == 0) 312 printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 313 } 314 315 /* 316 * Dump the entire arp table 317 */ 318 dump(addr) 319 u_long addr; 320 { 321 int mib[6]; 322 size_t needed; 323 char *host, *malloc(), *lim, *buf, *next; 324 struct rt_msghdr *rtm; 325 struct sockaddr_inarp *sin; 326 struct sockaddr_dl *sdl; 327 extern int h_errno; 328 struct hostent *hp; 329 330 mib[0] = CTL_NET; 331 mib[1] = PF_ROUTE; 332 mib[2] = 0; 333 mib[3] = AF_INET; 334 mib[4] = NET_RT_FLAGS; 335 mib[5] = RTF_LLINFO; 336 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 337 quit("route-sysctl-estimate"); 338 if ((buf = malloc(needed)) == NULL) 339 quit("malloc"); 340 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 341 quit("actual retrieval of routing table"); 342 lim = buf + needed; 343 for (next = buf; next < lim; next += rtm->rtm_msglen) { 344 rtm = (struct rt_msghdr *)next; 345 sin = (struct sockaddr_inarp *)(rtm + 1); 346 sdl = (struct sockaddr_dl *)(sin + 1); 347 if (addr) { 348 if (addr != sin->sin_addr.s_addr) 349 continue; 350 found_entry = 1; 351 } 352 if (nflag == 0) 353 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 354 sizeof sin->sin_addr, AF_INET); 355 else 356 hp = 0; 357 if (hp) 358 host = hp->h_name; 359 else { 360 host = "?"; 361 if (h_errno == TRY_AGAIN) 362 nflag = 1; 363 } 364 printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 365 if (sdl->sdl_alen) 366 ether_print(LLADDR(sdl)); 367 else 368 printf("(incomplete)"); 369 if (rtm->rtm_rmx.rmx_expire == 0) 370 printf(" permanent"); 371 if (sin->sin_other & SIN_PROXY) 372 printf(" published (proxy only)"); 373 if (rtm->rtm_addrs & RTA_NETMASK) { 374 sin = (struct sockaddr_inarp *) 375 (sdl->sdl_len + (char *)sdl); 376 if (sin->sin_addr.s_addr == 0xffffffff) 377 printf(" published"); 378 if (sin->sin_len != 8) 379 printf("(wierd)"); 380 } 381 printf("\n"); 382 } 383 } 384 385 ether_print(cp) 386 u_char *cp; 387 { 388 printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]); 389 } 390 391 ether_aton(a, n) 392 char *a; 393 u_char *n; 394 { 395 int i, o[6]; 396 397 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], 398 &o[3], &o[4], &o[5]); 399 if (i != 6) { 400 fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a); 401 return (1); 402 } 403 for (i=0; i<6; i++) 404 n[i] = o[i]; 405 return (0); 406 } 407 408 usage() 409 { 410 printf("usage: arp hostname\n"); 411 printf(" arp -a [kernel] [kernel_memory]\n"); 412 printf(" arp -d hostname\n"); 413 printf(" arp -s hostname ether_addr [temp] [pub]\n"); 414 printf(" arp -f filename\n"); 415 exit(1); 416 } 417 418 rtmsg(cmd) 419 { 420 static int seq; 421 int rlen; 422 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 423 register char *cp = m_rtmsg.m_space; 424 register int l; 425 426 errno = 0; 427 if (cmd == RTM_DELETE) 428 goto doit; 429 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 430 rtm->rtm_flags = flags; 431 rtm->rtm_version = RTM_VERSION; 432 433 switch (cmd) { 434 default: 435 fprintf(stderr, "arp: internal wrong cmd\n"); 436 exit(1); 437 case RTM_ADD: 438 rtm->rtm_addrs |= RTA_GATEWAY; 439 rtm->rtm_rmx.rmx_expire = expire_time; 440 rtm->rtm_inits = RTV_EXPIRE; 441 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 442 sin_m.sin_other = 0; 443 if (doing_proxy) { 444 if (export_only) 445 sin_m.sin_other = SIN_PROXY; 446 else { 447 rtm->rtm_addrs |= RTA_NETMASK; 448 rtm->rtm_flags &= ~RTF_HOST; 449 } 450 } 451 case RTM_GET: 452 rtm->rtm_addrs |= RTA_DST; 453 } 454 #define NEXTADDR(w, s) \ 455 if (rtm->rtm_addrs & (w)) { \ 456 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 457 458 NEXTADDR(RTA_DST, sin_m); 459 NEXTADDR(RTA_GATEWAY, sdl_m); 460 NEXTADDR(RTA_NETMASK, so_mask); 461 462 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 463 doit: 464 l = rtm->rtm_msglen; 465 rtm->rtm_seq = ++seq; 466 rtm->rtm_type = cmd; 467 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 468 if (errno != ESRCH || cmd != RTM_DELETE) { 469 perror("writing to routing socket"); 470 return (-1); 471 } 472 } 473 do { 474 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 475 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 476 if (l < 0) 477 (void) fprintf(stderr, "arp: read from routing socket: %s\n", 478 strerror(errno)); 479 return (0); 480 } 481 482 quit(msg) 483 char *msg; 484 { 485 fprintf(stderr, "%s\n", msg); 486 exit(1); 487 } 488