1 /* 2 * Copyright (c) 1984 Regents of the University of California. 3 * 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 char copyright[] = 13 "@(#) Copyright (c) 1984 Regents of the University of California.\n\ 14 All rights reserved.\n"; 15 #endif /* not lint */ 16 17 #ifndef lint 18 static char sccsid[] = "@(#)arp.c 5.16 (Berkeley) 03/08/93"; 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/kinfo.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 sz, needed, rlen; 322 long op = KINFO_RT_FLAGS | (((long)AF_INET) << 16); 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 if ((needed = getkerninfo(op, 0, 0, RTF_LLINFO)) < 0) 331 quit("route-getkerninfo-estimate"); 332 if ((buf = malloc(needed)) == NULL) 333 quit("malloc"); 334 if ((rlen = getkerninfo(op, buf, &needed, RTF_LLINFO)) < 0) 335 quit("actual retrieval of routing table"); 336 lim = buf + rlen; 337 for (next = buf; next < lim; next += rtm->rtm_msglen) { 338 rtm = (struct rt_msghdr *)next; 339 sin = (struct sockaddr_inarp *)(rtm + 1); 340 sdl = (struct sockaddr_dl *)(sin + 1); 341 if (addr) { 342 if (addr != sin->sin_addr.s_addr) 343 continue; 344 found_entry = 1; 345 } 346 if (nflag == 0) 347 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 348 sizeof sin->sin_addr, AF_INET); 349 else 350 hp = 0; 351 if (hp) 352 host = hp->h_name; 353 else { 354 host = "?"; 355 if (h_errno == TRY_AGAIN) 356 nflag = 1; 357 } 358 printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 359 if (sdl->sdl_alen) 360 ether_print(LLADDR(sdl)); 361 else 362 printf("(incomplete)"); 363 if (rtm->rtm_rmx.rmx_expire == 0) 364 printf(" permanent"); 365 if (sin->sin_other & SIN_PROXY) 366 printf(" published (proxy only)"); 367 if (rtm->rtm_addrs & RTA_NETMASK) { 368 sin = (struct sockaddr_inarp *) 369 (sdl->sdl_len + (char *)sdl); 370 if (sin->sin_addr.s_addr == 0xffffffff) 371 printf(" published"); 372 if (sin->sin_len != 8) 373 printf("(wierd)"); 374 } 375 printf("\n"); 376 } 377 } 378 379 ether_print(cp) 380 u_char *cp; 381 { 382 printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]); 383 } 384 385 ether_aton(a, n) 386 char *a; 387 u_char *n; 388 { 389 int i, o[6]; 390 391 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], 392 &o[3], &o[4], &o[5]); 393 if (i != 6) { 394 fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a); 395 return (1); 396 } 397 for (i=0; i<6; i++) 398 n[i] = o[i]; 399 return (0); 400 } 401 402 usage() 403 { 404 printf("usage: arp hostname\n"); 405 printf(" arp -a [kernel] [kernel_memory]\n"); 406 printf(" arp -d hostname\n"); 407 printf(" arp -s hostname ether_addr [temp] [pub]\n"); 408 printf(" arp -f filename\n"); 409 exit(1); 410 } 411 412 rtmsg(cmd) 413 { 414 static int seq; 415 int rlen; 416 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 417 register char *cp = m_rtmsg.m_space; 418 register int l; 419 420 errno = 0; 421 if (cmd == RTM_DELETE) 422 goto doit; 423 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 424 rtm->rtm_flags = flags; 425 rtm->rtm_version = RTM_VERSION; 426 427 switch (cmd) { 428 default: 429 fprintf(stderr, "arp: internal wrong cmd\n"); 430 exit(1); 431 case RTM_ADD: 432 rtm->rtm_addrs |= RTA_GATEWAY; 433 rtm->rtm_rmx.rmx_expire = expire_time; 434 rtm->rtm_inits = RTV_EXPIRE; 435 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 436 sin_m.sin_other = 0; 437 if (doing_proxy) { 438 if (export_only) 439 sin_m.sin_other = SIN_PROXY; 440 else { 441 rtm->rtm_addrs |= RTA_NETMASK; 442 rtm->rtm_flags &= ~RTF_HOST; 443 } 444 } 445 case RTM_GET: 446 rtm->rtm_addrs |= RTA_DST; 447 } 448 #define NEXTADDR(w, s) \ 449 if (rtm->rtm_addrs & (w)) { \ 450 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 451 452 NEXTADDR(RTA_DST, sin_m); 453 NEXTADDR(RTA_GATEWAY, sdl_m); 454 NEXTADDR(RTA_NETMASK, so_mask); 455 456 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 457 doit: 458 l = rtm->rtm_msglen; 459 rtm->rtm_seq = ++seq; 460 rtm->rtm_type = cmd; 461 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 462 if (errno != ESRCH || cmd != RTM_DELETE) { 463 perror("writing to routing socket"); 464 return (-1); 465 } 466 } 467 do { 468 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 469 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 470 if (l < 0) 471 (void) fprintf(stderr, "arp: read from routing socket: %s\n", 472 strerror(errno)); 473 return (0); 474 } 475 476 quit(msg) 477 char *msg; 478 { 479 fprintf(stderr, "%s\n", msg); 480 exit(1); 481 } 482