1/* vi: set sw=4 ts=4: */ 2/* 3 * arp.c - Manipulate the system ARP cache 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License 7 * as published by the Free Software Foundation; either version 8 * 2 of the License, or (at your option) any later version. 9 * 10 * Author: Fred N. van Kempen, <waltje at uwalt.nl.mugnet.org> 11 * Busybox port: Paul van Gool <pvangool at mimotech.com> 12 * 13 * modified for getopt32 by Arne Bernin <arne [at] alamut.de> 14 */ 15 16#include "libbb.h" 17#include "inet_common.h" 18 19#include <arpa/inet.h> 20#include <net/if.h> 21#include <net/if_arp.h> 22#include <netinet/ether.h> 23#include <netpacket/packet.h> 24 25#define DEBUG 0 26 27#define DFLT_AF "inet" 28#define DFLT_HW "ether" 29 30#define ARP_OPT_A (0x1) 31#define ARP_OPT_p (0x2) 32#define ARP_OPT_H (0x4) 33#define ARP_OPT_t (0x8) 34#define ARP_OPT_i (0x10) 35#define ARP_OPT_a (0x20) 36#define ARP_OPT_d (0x40) 37#define ARP_OPT_n (0x80) /* do not resolve addresses */ 38#define ARP_OPT_D (0x100) /* HW-address is devicename */ 39#define ARP_OPT_s (0x200) 40#define ARP_OPT_v (0x400 * DEBUG) /* debugging output flag */ 41 42 43static const struct aftype *ap; /* current address family */ 44static const struct hwtype *hw; /* current hardware type */ 45static int sockfd; /* active socket descriptor */ 46static smallint hw_set; /* flag if hw-type was set (-H) */ 47static const char *device = ""; /* current device */ 48 49static const char options[] ALIGN1 = 50 "pub\0" 51 "priv\0" 52 "temp\0" 53 "trail\0" 54 "dontpub\0" 55 "auto\0" 56 "dev\0" 57 "netmask\0"; 58 59/* Delete an entry from the ARP cache. */ 60/* Called only from main, once */ 61static int arp_del(char **args) 62{ 63 char *host; 64 struct arpreq req; 65 struct sockaddr sa; 66 int flags = 0; 67 int err; 68 69 memset(&req, 0, sizeof(req)); 70 71 /* Resolve the host name. */ 72 host = *args; 73 if (ap->input(host, &sa) < 0) { 74 bb_herror_msg_and_die("%s", host); 75 } 76 77 /* If a host has more than one address, use the correct one! */ 78 memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr)); 79 80 if (hw_set) 81 req.arp_ha.sa_family = hw->type; 82 83 req.arp_flags = ATF_PERM; 84 args++; 85 while (*args != NULL) { 86 switch (index_in_strings(options, *args)) { 87 case 0: /* "pub" */ 88 flags |= 1; 89 args++; 90 break; 91 case 1: /* "priv" */ 92 flags |= 2; 93 args++; 94 break; 95 case 2: /* "temp" */ 96 req.arp_flags &= ~ATF_PERM; 97 args++; 98 break; 99 case 3: /* "trail" */ 100 req.arp_flags |= ATF_USETRAILERS; 101 args++; 102 break; 103 case 4: /* "dontpub" */ 104#ifdef HAVE_ATF_DONTPUB 105 req.arp_flags |= ATF_DONTPUB; 106#else 107 bb_error_msg("feature ATF_DONTPUB is not supported"); 108#endif 109 args++; 110 break; 111 case 5: /* "auto" */ 112#ifdef HAVE_ATF_MAGIC 113 req.arp_flags |= ATF_MAGIC; 114#else 115 bb_error_msg("feature ATF_MAGIC is not supported"); 116#endif 117 args++; 118 break; 119 case 6: /* "dev" */ 120 if (*++args == NULL) 121 bb_show_usage(); 122 device = *args; 123 args++; 124 break; 125 case 7: /* "netmask" */ 126 if (*++args == NULL) 127 bb_show_usage(); 128 if (strcmp(*args, "255.255.255.255") != 0) { 129 host = *args; 130 if (ap->input(host, &sa) < 0) { 131 bb_herror_msg_and_die("%s", host); 132 } 133 memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr)); 134 req.arp_flags |= ATF_NETMASK; 135 } 136 args++; 137 break; 138 default: 139 bb_show_usage(); 140 break; 141 } 142 } 143 if (flags == 0) 144 flags = 3; 145 146 strncpy(req.arp_dev, device, sizeof(req.arp_dev)); 147 148 err = -1; 149 150 /* Call the kernel. */ 151 if (flags & 2) { 152 if (option_mask32 & ARP_OPT_v) 153 bb_error_msg("SIOCDARP(nopub)"); 154 err = ioctl(sockfd, SIOCDARP, &req); 155 if (err < 0) { 156 if (errno == ENXIO) { 157 if (flags & 1) 158 goto nopub; 159 printf("No ARP entry for %s\n", host); 160 return -1; 161 } 162 bb_perror_msg_and_die("SIOCDARP(priv)"); 163 } 164 } 165 if ((flags & 1) && err) { 166 nopub: 167 req.arp_flags |= ATF_PUBL; 168 if (option_mask32 & ARP_OPT_v) 169 bb_error_msg("SIOCDARP(pub)"); 170 if (ioctl(sockfd, SIOCDARP, &req) < 0) { 171 if (errno == ENXIO) { 172 printf("No ARP entry for %s\n", host); 173 return -1; 174 } 175 bb_perror_msg_and_die("SIOCDARP(pub)"); 176 } 177 } 178 return 0; 179} 180 181/* Get the hardware address to a specified interface name */ 182static void arp_getdevhw(char *ifname, struct sockaddr *sa, 183 const struct hwtype *hwt) 184{ 185 struct ifreq ifr; 186 const struct hwtype *xhw; 187 188 strcpy(ifr.ifr_name, ifname); 189 ioctl_or_perror_and_die(sockfd, SIOCGIFHWADDR, &ifr, 190 "cant get HW-Address for '%s'", ifname); 191 if (hwt && (ifr.ifr_hwaddr.sa_family != hw->type)) { 192 bb_error_msg_and_die("protocol type mismatch"); 193 } 194 memcpy(sa, &(ifr.ifr_hwaddr), sizeof(struct sockaddr)); 195 196 if (option_mask32 & ARP_OPT_v) { 197 xhw = get_hwntype(ifr.ifr_hwaddr.sa_family); 198 if (!xhw || !xhw->print) { 199 xhw = get_hwntype(-1); 200 } 201 bb_error_msg("device '%s' has HW address %s '%s'", 202 ifname, xhw->name, 203 xhw->print((char *) &ifr.ifr_hwaddr.sa_data)); 204 } 205} 206 207/* Set an entry in the ARP cache. */ 208/* Called only from main, once */ 209static int arp_set(char **args) 210{ 211 char *host; 212 struct arpreq req; 213 struct sockaddr sa; 214 int flags; 215 216 memset(&req, 0, sizeof(req)); 217 218 host = *args++; 219 if (ap->input(host, &sa) < 0) { 220 bb_herror_msg_and_die("%s", host); 221 } 222 /* If a host has more than one address, use the correct one! */ 223 memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr)); 224 225 /* Fetch the hardware address. */ 226 if (*args == NULL) { 227 bb_error_msg_and_die("need hardware address"); 228 } 229 if (option_mask32 & ARP_OPT_D) { 230 arp_getdevhw(*args++, &req.arp_ha, hw_set ? hw : NULL); 231 } else { 232 if (hw->input(*args++, &req.arp_ha) < 0) { 233 bb_error_msg_and_die("invalid hardware address"); 234 } 235 } 236 237 /* Check out any modifiers. */ 238 flags = ATF_PERM | ATF_COM; 239 while (*args != NULL) { 240 switch (index_in_strings(options, *args)) { 241 case 0: /* "pub" */ 242 flags |= ATF_PUBL; 243 args++; 244 break; 245 case 1: /* "priv" */ 246 flags &= ~ATF_PUBL; 247 args++; 248 break; 249 case 2: /* "temp" */ 250 flags &= ~ATF_PERM; 251 args++; 252 break; 253 case 3: /* "trail" */ 254 flags |= ATF_USETRAILERS; 255 args++; 256 break; 257 case 4: /* "dontpub" */ 258#ifdef HAVE_ATF_DONTPUB 259 flags |= ATF_DONTPUB; 260#else 261 bb_error_msg("feature ATF_DONTPUB is not supported"); 262#endif 263 args++; 264 break; 265 case 5: /* "auto" */ 266#ifdef HAVE_ATF_MAGIC 267 flags |= ATF_MAGIC; 268#else 269 bb_error_msg("feature ATF_MAGIC is not supported"); 270#endif 271 args++; 272 break; 273 case 6: /* "dev" */ 274 if (*++args == NULL) 275 bb_show_usage(); 276 device = *args; 277 args++; 278 break; 279 case 7: /* "netmask" */ 280 if (*++args == NULL) 281 bb_show_usage(); 282 if (strcmp(*args, "255.255.255.255") != 0) { 283 host = *args; 284 if (ap->input(host, &sa) < 0) { 285 bb_herror_msg_and_die("%s", host); 286 } 287 memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr)); 288 flags |= ATF_NETMASK; 289 } 290 args++; 291 break; 292 default: 293 bb_show_usage(); 294 break; 295 } 296 } 297 298 /* Fill in the remainder of the request. */ 299 req.arp_flags = flags; 300 301 strncpy(req.arp_dev, device, sizeof(req.arp_dev)); 302 303 /* Call the kernel. */ 304 if (option_mask32 & ARP_OPT_v) 305 bb_error_msg("SIOCSARP()"); 306 xioctl(sockfd, SIOCSARP, &req); 307 return 0; 308} 309 310 311/* Print the contents of an ARP request block. */ 312static void 313arp_disp(const char *name, char *ip, int type, int arp_flags, 314 char *hwa, char *mask, char *dev) 315{ 316 const struct hwtype *xhw; 317 318 xhw = get_hwntype(type); 319 if (xhw == NULL) 320 xhw = get_hwtype(DFLT_HW); 321 322 printf("%s (%s) at ", name, ip); 323 324 if (!(arp_flags & ATF_COM)) { 325 if (arp_flags & ATF_PUBL) 326 printf("* "); 327 else 328 printf("<incomplete> "); 329 } else { 330 printf("%s [%s] ", hwa, xhw->name); 331 } 332 333 if (arp_flags & ATF_NETMASK) 334 printf("netmask %s ", mask); 335 336 if (arp_flags & ATF_PERM) 337 printf("PERM "); 338 if (arp_flags & ATF_PUBL) 339 printf("PUP "); 340#ifdef HAVE_ATF_MAGIC 341 if (arp_flags & ATF_MAGIC) 342 printf("AUTO "); 343#endif 344#ifdef HAVE_ATF_DONTPUB 345 if (arp_flags & ATF_DONTPUB) 346 printf("DONTPUB "); 347#endif 348 if (arp_flags & ATF_USETRAILERS) 349 printf("TRAIL "); 350 351 printf("on %s\n", dev); 352} 353 354/* Display the contents of the ARP cache in the kernel. */ 355/* Called only from main, once */ 356static int arp_show(char *name) 357{ 358 const char *host; 359 const char *hostname; 360 FILE *fp; 361 struct sockaddr sa; 362 int type, flags; 363 int num; 364 unsigned entries = 0, shown = 0; 365 char ip[128]; 366 char hwa[128]; 367 char mask[128]; 368 char line[128]; 369 char dev[128]; 370 371 host = NULL; 372 if (name != NULL) { 373 /* Resolve the host name. */ 374 if (ap->input(name, &sa) < 0) { 375 bb_herror_msg_and_die("%s", name); 376 } 377 host = xstrdup(ap->sprint(&sa, 1)); 378 } 379 fp = xfopen("/proc/net/arp", "r"); 380 /* Bypass header -- read one line */ 381 fgets(line, sizeof(line), fp); 382 383 /* Read the ARP cache entries. */ 384 while (fgets(line, sizeof(line), fp)) { 385 386 mask[0] = '-'; mask[1] = '\0'; 387 dev[0] = '-'; dev[1] = '\0'; 388 /* All these strings can't overflow 389 * because fgets above reads limited amount of data */ 390 num = sscanf(line, "%s 0x%x 0x%x %s %s %s\n", 391 ip, &type, &flags, hwa, mask, dev); 392 if (num < 4) 393 break; 394 395 entries++; 396 /* if the user specified hw-type differs, skip it */ 397 if (hw_set && (type != hw->type)) 398 continue; 399 400 /* if the user specified address differs, skip it */ 401 if (host && strcmp(ip, host) != 0) 402 continue; 403 404 /* if the user specified device differs, skip it */ 405 if (device[0] && strcmp(dev, device) != 0) 406 continue; 407 408 shown++; 409 /* This IS ugly but it works -be */ 410 hostname = "?"; 411 if (!(option_mask32 & ARP_OPT_n)) { 412 if (ap->input(ip, &sa) < 0) 413 hostname = ip; 414 else 415 hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) | 0x8000); 416 if (strcmp(hostname, ip) == 0) 417 hostname = "?"; 418 } 419 420 arp_disp(hostname, ip, type, flags, hwa, mask, dev); 421 } 422 if (option_mask32 & ARP_OPT_v) 423 printf("Entries: %d\tSkipped: %d\tFound: %d\n", 424 entries, entries - shown, shown); 425 426 if (!shown) { 427 if (hw_set || host || device[0]) 428 printf("No match found in %d entries\n", entries); 429 } 430 if (ENABLE_FEATURE_CLEAN_UP) { 431 free((char*)host); 432 fclose(fp); 433 } 434 return 0; 435} 436 437int arp_main(int argc, char **argv); 438int arp_main(int argc, char **argv) 439{ 440 char *hw_type; 441 char *protocol; 442 443 /* Initialize variables... */ 444 ap = get_aftype(DFLT_AF); 445 if (!ap) 446 bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family"); 447 448 getopt32(argv, "A:p:H:t:i:adnDsv", &protocol, &protocol, 449 &hw_type, &hw_type, &device); 450 argv += optind; 451 if (option_mask32 & ARP_OPT_A || option_mask32 & ARP_OPT_p) { 452 ap = get_aftype(protocol); 453 if (ap == NULL) 454 bb_error_msg_and_die("%s: unknown %s", protocol, "address family"); 455 } 456 if (option_mask32 & ARP_OPT_A || option_mask32 & ARP_OPT_p) { 457 hw = get_hwtype(hw_type); 458 if (hw == NULL) 459 bb_error_msg_and_die("%s: unknown %s", hw_type, "hardware type"); 460 hw_set = 1; 461 } 462 //if (option_mask32 & ARP_OPT_i)... -i 463 464 if (ap->af != AF_INET) { 465 bb_error_msg_and_die("%s: kernel only supports 'inet'", ap->name); 466 } 467 468 /* If no hw type specified get default */ 469 if (!hw) { 470 hw = get_hwtype(DFLT_HW); 471 if (!hw) 472 bb_error_msg_and_die("%s: %s not supported", DFLT_HW, "hardware type"); 473 } 474 475 if (hw->alen <= 0) { 476 bb_error_msg_and_die("%s: %s without ARP support", 477 hw->name, "hardware type"); 478 } 479 sockfd = xsocket(AF_INET, SOCK_DGRAM, 0); 480 481 /* Now see what we have to do here... */ 482 if (option_mask32 & (ARP_OPT_d|ARP_OPT_s)) { 483 if (argv[0] == NULL) 484 bb_error_msg_and_die("need host name"); 485 if (option_mask32 & ARP_OPT_s) 486 return arp_set(argv); 487 return arp_del(argv); 488 } 489 //if (option_mask32 & ARP_OPT_a) - default 490 return arp_show(argv[0]); 491} 492