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 8.3 (Berkeley) 04/28/95"; 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 <err.h> 42 #include <errno.h> 43 #include <netdb.h> 44 #include <nlist.h> 45 #include <paths.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 51 static int pid; 52 static int nflag; 53 static int s = -1; 54 55 int delete __P((char *, char *)); 56 void dump __P((u_long)); 57 int ether_aton __P((char *, u_char *)); 58 void ether_print __P((u_char *)); 59 int file __P((char *)); 60 void get __P((char *)); 61 void getsocket __P((void)); 62 int rtmsg __P((int)); 63 int set __P((int, char **)); 64 void usage __P((void)); 65 66 int 67 main(argc, argv) 68 int argc; 69 char **argv; 70 { 71 int ch; 72 73 pid = getpid(); 74 while ((ch = getopt(argc, argv, "ands")) != EOF) 75 switch((char)ch) { 76 case 'a': 77 dump(0); 78 exit(0); 79 case 'd': 80 if (argc < 3 || argc > 4) 81 usage(); 82 delete(argv[2], argv[3]); 83 exit(0); 84 case 'n': 85 nflag = 1; 86 continue; 87 case 's': 88 if (argc < 4 || argc > 7) 89 usage(); 90 exit(set(argc-2, &argv[2]) ? 1 : 0); 91 case '?': 92 default: 93 usage(); 94 } 95 if (argc != 2) 96 usage(); 97 get(argv[1]); 98 return (0); 99 } 100 101 /* 102 * Process a file to set standard arp entries 103 */ 104 int 105 file(name) 106 char *name; 107 { 108 FILE *fp; 109 int i, retval; 110 char line[100], arg[5][50], *args[5]; 111 112 if ((fp = fopen(name, "r")) == NULL) { 113 fprintf(stderr, "arp: cannot open %s\n", name); 114 exit(1); 115 } 116 args[0] = &arg[0][0]; 117 args[1] = &arg[1][0]; 118 args[2] = &arg[2][0]; 119 args[3] = &arg[3][0]; 120 args[4] = &arg[4][0]; 121 retval = 0; 122 while(fgets(line, 100, fp) != NULL) { 123 i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2], 124 arg[3], arg[4]); 125 if (i < 2) { 126 fprintf(stderr, "arp: bad line: %s\n", line); 127 retval = 1; 128 continue; 129 } 130 if (set(i, args)) 131 retval = 1; 132 } 133 fclose(fp); 134 return (retval); 135 } 136 137 void 138 getsocket() { 139 if (s < 0) { 140 s = socket(PF_ROUTE, SOCK_RAW, 0); 141 if (s < 0) { 142 perror("arp: socket"); 143 exit(1); 144 } 145 } 146 } 147 148 struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 149 struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 150 struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 151 int expire_time, flags, export_only, doing_proxy, found_entry; 152 struct { 153 struct rt_msghdr m_rtm; 154 char m_space[512]; 155 } m_rtmsg; 156 157 /* 158 * Set an individual arp entry 159 */ 160 int 161 set(argc, argv) 162 int argc; 163 char **argv; 164 { 165 struct hostent *hp; 166 register struct sockaddr_inarp *sin = &sin_m; 167 register struct sockaddr_dl *sdl; 168 register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 169 u_char *ea; 170 char *host = argv[0], *eaddr = argv[1]; 171 172 getsocket(); 173 argc -= 2; 174 argv += 2; 175 sdl_m = blank_sdl; 176 sin_m = blank_sin; 177 sin->sin_addr.s_addr = inet_addr(host); 178 if (sin->sin_addr.s_addr == -1) { 179 if (!(hp = gethostbyname(host))) { 180 fprintf(stderr, "arp: %s: ", host); 181 herror((char *)NULL); 182 return (1); 183 } 184 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 185 sizeof sin->sin_addr); 186 } 187 ea = (u_char *)LLADDR(&sdl_m); 188 if (ether_aton(eaddr, ea) == 0) 189 sdl_m.sdl_alen = 6; 190 doing_proxy = flags = export_only = expire_time = 0; 191 while (argc-- > 0) { 192 if (strncmp(argv[0], "temp", 4) == 0) { 193 struct timeval time; 194 gettimeofday(&time, 0); 195 expire_time = time.tv_sec + 20 * 60; 196 } 197 else if (strncmp(argv[0], "pub", 3) == 0) { 198 flags |= RTF_ANNOUNCE; 199 doing_proxy = SIN_PROXY; 200 } else if (strncmp(argv[0], "trail", 5) == 0) { 201 printf("%s: Sending trailers is no longer supported\n", 202 host); 203 } 204 argv++; 205 } 206 tryagain: 207 if (rtmsg(RTM_GET) < 0) { 208 perror(host); 209 return (1); 210 } 211 sin = (struct sockaddr_inarp *)(rtm + 1); 212 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 213 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 214 if (sdl->sdl_family == AF_LINK && 215 (rtm->rtm_flags & RTF_LLINFO) && 216 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 217 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 218 case IFT_ISO88024: case IFT_ISO88025: 219 goto overwrite; 220 } 221 if (doing_proxy == 0) { 222 printf("set: can only proxy for %s\n", host); 223 return (1); 224 } 225 if (sin_m.sin_other & SIN_PROXY) { 226 printf("set: proxy entry exists for non 802 device\n"); 227 return(1); 228 } 229 sin_m.sin_other = SIN_PROXY; 230 export_only = 1; 231 goto tryagain; 232 } 233 overwrite: 234 if (sdl->sdl_family != AF_LINK) { 235 printf("cannot intuit interface index and type for %s\n", host); 236 return (1); 237 } 238 sdl_m.sdl_type = sdl->sdl_type; 239 sdl_m.sdl_index = sdl->sdl_index; 240 return (rtmsg(RTM_ADD)); 241 } 242 243 /* 244 * Display an individual arp entry 245 */ 246 void 247 get(host) 248 char *host; 249 { 250 struct hostent *hp; 251 struct sockaddr_inarp *sin = &sin_m; 252 253 sin_m = blank_sin; 254 sin->sin_addr.s_addr = inet_addr(host); 255 if (sin->sin_addr.s_addr == -1) { 256 if (!(hp = gethostbyname(host))) { 257 fprintf(stderr, "arp: %s: ", host); 258 herror((char *)NULL); 259 exit(1); 260 } 261 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 262 sizeof sin->sin_addr); 263 } 264 dump(sin->sin_addr.s_addr); 265 if (found_entry == 0) { 266 printf("%s (%s) -- no entry\n", 267 host, inet_ntoa(sin->sin_addr)); 268 exit(1); 269 } 270 } 271 272 /* 273 * Delete an arp entry 274 */ 275 int 276 delete(host, info) 277 char *host; 278 char *info; 279 { 280 struct hostent *hp; 281 register struct sockaddr_inarp *sin = &sin_m; 282 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 283 struct sockaddr_dl *sdl; 284 285 if (info && strncmp(info, "pro", 3) ) 286 export_only = 1; 287 getsocket(); 288 sin_m = blank_sin; 289 sin->sin_addr.s_addr = inet_addr(host); 290 if (sin->sin_addr.s_addr == -1) { 291 if (!(hp = gethostbyname(host))) { 292 fprintf(stderr, "arp: %s: ", host); 293 herror((char *)NULL); 294 return (1); 295 } 296 bcopy((char *)hp->h_addr, (char *)&sin->sin_addr, 297 sizeof sin->sin_addr); 298 } 299 tryagain: 300 if (rtmsg(RTM_GET) < 0) { 301 perror(host); 302 return (1); 303 } 304 sin = (struct sockaddr_inarp *)(rtm + 1); 305 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 306 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 307 if (sdl->sdl_family == AF_LINK && 308 (rtm->rtm_flags & RTF_LLINFO) && 309 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 310 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 311 case IFT_ISO88024: case IFT_ISO88025: 312 goto delete; 313 } 314 } 315 if (sin_m.sin_other & SIN_PROXY) { 316 fprintf(stderr, "delete: can't locate %s\n",host); 317 return (1); 318 } else { 319 sin_m.sin_other = SIN_PROXY; 320 goto tryagain; 321 } 322 delete: 323 if (sdl->sdl_family != AF_LINK) { 324 printf("cannot locate %s\n", host); 325 return (1); 326 } 327 if (rtmsg(RTM_DELETE)) 328 return (1); 329 printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr)); 330 return (0); 331 } 332 333 /* 334 * Dump the entire arp table 335 */ 336 void 337 dump(addr) 338 u_long addr; 339 { 340 int mib[6]; 341 size_t needed; 342 char *host, *lim, *buf, *next; 343 struct rt_msghdr *rtm; 344 struct sockaddr_inarp *sin; 345 struct sockaddr_dl *sdl; 346 extern int h_errno; 347 struct hostent *hp; 348 349 mib[0] = CTL_NET; 350 mib[1] = PF_ROUTE; 351 mib[2] = 0; 352 mib[3] = AF_INET; 353 mib[4] = NET_RT_FLAGS; 354 mib[5] = RTF_LLINFO; 355 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) 356 err(1, "route-sysctl-estimate"); 357 if ((buf = malloc(needed)) == NULL) 358 err(1, "malloc"); 359 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) 360 err(1, "actual retrieval of routing table"); 361 lim = buf + needed; 362 for (next = buf; next < lim; next += rtm->rtm_msglen) { 363 rtm = (struct rt_msghdr *)next; 364 sin = (struct sockaddr_inarp *)(rtm + 1); 365 sdl = (struct sockaddr_dl *)(sin + 1); 366 if (addr) { 367 if (addr != sin->sin_addr.s_addr) 368 continue; 369 found_entry = 1; 370 } 371 if (nflag == 0) 372 hp = gethostbyaddr((caddr_t)&(sin->sin_addr), 373 sizeof sin->sin_addr, AF_INET); 374 else 375 hp = 0; 376 if (hp) 377 host = hp->h_name; 378 else { 379 host = "?"; 380 if (h_errno == TRY_AGAIN) 381 nflag = 1; 382 } 383 printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr)); 384 if (sdl->sdl_alen) 385 ether_print((u_char *)LLADDR(sdl)); 386 else 387 printf("(incomplete)"); 388 if (rtm->rtm_rmx.rmx_expire == 0) 389 printf(" permanent"); 390 if (sin->sin_other & SIN_PROXY) 391 printf(" published (proxy only)"); 392 if (rtm->rtm_addrs & RTA_NETMASK) { 393 sin = (struct sockaddr_inarp *) 394 (sdl->sdl_len + (char *)sdl); 395 if (sin->sin_addr.s_addr == 0xffffffff) 396 printf(" published"); 397 if (sin->sin_len != 8) 398 printf("(wierd)"); 399 } 400 printf("\n"); 401 } 402 } 403 404 void 405 ether_print(cp) 406 u_char *cp; 407 { 408 printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]); 409 } 410 411 int 412 ether_aton(a, n) 413 char *a; 414 u_char *n; 415 { 416 int i, o[6]; 417 418 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2], 419 &o[3], &o[4], &o[5]); 420 if (i != 6) { 421 fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a); 422 return (1); 423 } 424 for (i=0; i<6; i++) 425 n[i] = o[i]; 426 return (0); 427 } 428 429 void 430 usage() 431 { 432 printf("usage: arp hostname\n"); 433 printf(" arp -a [kernel] [kernel_memory]\n"); 434 printf(" arp -d hostname\n"); 435 printf(" arp -s hostname ether_addr [temp] [pub]\n"); 436 printf(" arp -f filename\n"); 437 exit(1); 438 } 439 440 int 441 rtmsg(cmd) 442 int cmd; 443 { 444 static int seq; 445 int rlen; 446 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 447 register char *cp = m_rtmsg.m_space; 448 register int l; 449 450 errno = 0; 451 if (cmd == RTM_DELETE) 452 goto doit; 453 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 454 rtm->rtm_flags = flags; 455 rtm->rtm_version = RTM_VERSION; 456 457 switch (cmd) { 458 default: 459 fprintf(stderr, "arp: internal wrong cmd\n"); 460 exit(1); 461 case RTM_ADD: 462 rtm->rtm_addrs |= RTA_GATEWAY; 463 rtm->rtm_rmx.rmx_expire = expire_time; 464 rtm->rtm_inits = RTV_EXPIRE; 465 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 466 sin_m.sin_other = 0; 467 if (doing_proxy) { 468 if (export_only) 469 sin_m.sin_other = SIN_PROXY; 470 else { 471 rtm->rtm_addrs |= RTA_NETMASK; 472 rtm->rtm_flags &= ~RTF_HOST; 473 } 474 } 475 /* FALLTHROUGH */ 476 case RTM_GET: 477 rtm->rtm_addrs |= RTA_DST; 478 } 479 #define NEXTADDR(w, s) \ 480 if (rtm->rtm_addrs & (w)) { \ 481 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 482 483 NEXTADDR(RTA_DST, sin_m); 484 NEXTADDR(RTA_GATEWAY, sdl_m); 485 NEXTADDR(RTA_NETMASK, so_mask); 486 487 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 488 doit: 489 l = rtm->rtm_msglen; 490 rtm->rtm_seq = ++seq; 491 rtm->rtm_type = cmd; 492 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 493 if (errno != ESRCH || cmd != RTM_DELETE) { 494 perror("writing to routing socket"); 495 return (-1); 496 } 497 } 498 do { 499 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 500 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 501 if (l < 0) 502 (void) fprintf(stderr, "arp: read from routing socket: %s\n", 503 strerror(errno)); 504 return (0); 505 } 506