1 /* vi: set sw=4 ts=4: */
3 * arp.c - Manipulate the system ARP cache
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.
10 * Author: Fred N. van Kempen, <waltje at uwalt.nl.mugnet.org>
11 * Busybox port: Paul van Gool <pvangool at mimotech.com>
13 * modified for getopt32 by Arne Bernin <arne [at] alamut.de>
16 //usage:#define arp_trivial_usage
17 //usage: "\n[-vn] [-H HWTYPE] [-i IF] -a [HOSTNAME]"
18 //usage: "\n[-v] [-i IF] -d HOSTNAME [pub]"
19 //usage: "\n[-v] [-H HWTYPE] [-i IF] -s HOSTNAME HWADDR [temp]"
20 //usage: "\n[-v] [-H HWTYPE] [-i IF] -s HOSTNAME HWADDR [netmask MASK] pub"
21 //usage: "\n[-v] [-H HWTYPE] [-i IF] -Ds HOSTNAME IFACE [netmask MASK] pub"
22 //usage:#define arp_full_usage "\n\n"
23 //usage: "Manipulate ARP cache\n"
24 //usage: "\n -a Display (all) hosts"
25 //usage: "\n -d Delete ARP entry"
26 //usage: "\n -s Set new entry"
27 //usage: "\n -v Verbose"
28 //usage: "\n -n Don't resolve names"
29 //usage: "\n -i IF Network interface"
30 //usage: "\n -D Read HWADDR from IFACE"
31 //usage: "\n -A,-p AF Protocol family"
32 //usage: "\n -H HWTYPE Hardware address type"
35 #include "inet_common.h"
37 #include <arpa/inet.h>
39 #include <net/if_arp.h>
40 #include <netinet/ether.h>
41 #include <netpacket/packet.h>
45 #define DFLT_AF "inet"
46 #define DFLT_HW "ether"
56 ARP_OPT_n = (1 << 7), /* do not resolve addresses */
57 ARP_OPT_D = (1 << 8), /* HW-address is devicename */
59 ARP_OPT_v = (1 << 10) * DEBUG, /* debugging output flag */
63 sockfd = 3, /* active socket descriptor */
67 const struct aftype *ap; /* current address family */
68 const struct hwtype *hw; /* current hardware type */
69 const char *device; /* current device */
70 smallint hw_set; /* flag if hw-type was set (-H) */
72 #define G (*(struct globals*)&bb_common_bufsiz1)
75 #define device (G.device )
76 #define hw_set (G.hw_set )
77 #define INIT_G() do { \
82 static const char options[] ALIGN1 =
92 /* Delete an entry from the ARP cache. */
93 /* Called only from main, once */
94 static int arp_del(char **args)
102 memset(&req, 0, sizeof(req));
104 /* Resolve the host name. */
106 if (ap->input(host, &sa) < 0) {
107 bb_herror_msg_and_die("%s", host);
110 /* If a host has more than one address, use the correct one! */
111 memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
114 req.arp_ha.sa_family = hw->type;
116 req.arp_flags = ATF_PERM;
118 while (*args != NULL) {
119 switch (index_in_strings(options, *args)) {
129 req.arp_flags &= ~ATF_PERM;
132 case 3: /* "trail" */
133 req.arp_flags |= ATF_USETRAILERS;
136 case 4: /* "dontpub" */
137 #ifdef HAVE_ATF_DONTPUB
138 req.arp_flags |= ATF_DONTPUB;
140 bb_error_msg("feature ATF_DONTPUB is not supported");
145 #ifdef HAVE_ATF_MAGIC
146 req.arp_flags |= ATF_MAGIC;
148 bb_error_msg("feature ATF_MAGIC is not supported");
158 case 7: /* "netmask" */
161 if (strcmp(*args, "255.255.255.255") != 0) {
163 if (ap->input(host, &sa) < 0) {
164 bb_herror_msg_and_die("%s", host);
166 memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
167 req.arp_flags |= ATF_NETMASK;
179 strncpy(req.arp_dev, device, sizeof(req.arp_dev));
183 /* Call the kernel. */
185 if (option_mask32 & ARP_OPT_v)
186 bb_error_msg("SIOCDARP(nopub)");
187 err = ioctl(sockfd, SIOCDARP, &req);
189 if (errno == ENXIO) {
192 printf("No ARP entry for %s\n", host);
195 bb_perror_msg_and_die("SIOCDARP(priv)");
198 if ((flags & 1) && err) {
200 req.arp_flags |= ATF_PUBL;
201 if (option_mask32 & ARP_OPT_v)
202 bb_error_msg("SIOCDARP(pub)");
203 if (ioctl(sockfd, SIOCDARP, &req) < 0) {
204 if (errno == ENXIO) {
205 printf("No ARP entry for %s\n", host);
208 bb_perror_msg_and_die("SIOCDARP(pub)");
214 /* Get the hardware address to a specified interface name */
215 static void arp_getdevhw(char *ifname, struct sockaddr *sa)
218 const struct hwtype *xhw;
220 strcpy(ifr.ifr_name, ifname);
221 ioctl_or_perror_and_die(sockfd, SIOCGIFHWADDR, &ifr,
222 "can't get HW-Address for '%s'", ifname);
223 if (hw_set && (ifr.ifr_hwaddr.sa_family != hw->type)) {
224 bb_error_msg_and_die("protocol type mismatch");
226 memcpy(sa, &(ifr.ifr_hwaddr), sizeof(struct sockaddr));
228 if (option_mask32 & ARP_OPT_v) {
229 xhw = get_hwntype(ifr.ifr_hwaddr.sa_family);
230 if (!xhw || !xhw->print) {
231 xhw = get_hwntype(-1);
233 bb_error_msg("device '%s' has HW address %s '%s'",
235 xhw->print((unsigned char *) &ifr.ifr_hwaddr.sa_data));
239 /* Set an entry in the ARP cache. */
240 /* Called only from main, once */
241 static int arp_set(char **args)
248 memset(&req, 0, sizeof(req));
251 if (ap->input(host, &sa) < 0) {
252 bb_herror_msg_and_die("%s", host);
254 /* If a host has more than one address, use the correct one! */
255 memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
257 /* Fetch the hardware address. */
259 bb_error_msg_and_die("need hardware address");
261 if (option_mask32 & ARP_OPT_D) {
262 arp_getdevhw(*args++, &req.arp_ha);
264 if (hw->input(*args++, &req.arp_ha) < 0) {
265 bb_error_msg_and_die("invalid hardware address");
269 /* Check out any modifiers. */
270 flags = ATF_PERM | ATF_COM;
271 while (*args != NULL) {
272 switch (index_in_strings(options, *args)) {
285 case 3: /* "trail" */
286 flags |= ATF_USETRAILERS;
289 case 4: /* "dontpub" */
290 #ifdef HAVE_ATF_DONTPUB
291 flags |= ATF_DONTPUB;
293 bb_error_msg("feature ATF_DONTPUB is not supported");
298 #ifdef HAVE_ATF_MAGIC
301 bb_error_msg("feature ATF_MAGIC is not supported");
311 case 7: /* "netmask" */
314 if (strcmp(*args, "255.255.255.255") != 0) {
316 if (ap->input(host, &sa) < 0) {
317 bb_herror_msg_and_die("%s", host);
319 memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
320 flags |= ATF_NETMASK;
330 /* Fill in the remainder of the request. */
331 req.arp_flags = flags;
333 strncpy(req.arp_dev, device, sizeof(req.arp_dev));
335 /* Call the kernel. */
336 if (option_mask32 & ARP_OPT_v)
337 bb_error_msg("SIOCSARP()");
338 xioctl(sockfd, SIOCSARP, &req);
343 /* Print the contents of an ARP request block. */
345 arp_disp(const char *name, char *ip, int type, int arp_flags,
346 char *hwa, char *mask, char *dev)
348 static const int arp_masks[] = {
350 #ifdef HAVE_ATF_MAGIC
353 #ifdef HAVE_ATF_DONTPUB
358 static const char arp_labels[] ALIGN1 = "PERM\0""PUP\0"
359 #ifdef HAVE_ATF_MAGIC
362 #ifdef HAVE_ATF_DONTPUB
368 const struct hwtype *xhw;
370 xhw = get_hwntype(type);
372 xhw = get_hwtype(DFLT_HW);
374 printf("%s (%s) at ", name, ip);
376 if (!(arp_flags & ATF_COM)) {
377 if (arp_flags & ATF_PUBL)
380 printf("<incomplete> ");
382 printf("%s [%s] ", hwa, xhw->name);
385 if (arp_flags & ATF_NETMASK)
386 printf("netmask %s ", mask);
388 print_flags_separated(arp_masks, arp_labels, arp_flags, " ");
389 printf(" on %s\n", dev);
392 /* Display the contents of the ARP cache in the kernel. */
393 /* Called only from main, once */
394 static int arp_show(char *name)
397 const char *hostname;
402 unsigned entries = 0, shown = 0;
411 /* Resolve the host name. */
412 if (ap->input(name, &sa) < 0) {
413 bb_herror_msg_and_die("%s", name);
415 host = xstrdup(ap->sprint(&sa, 1));
417 fp = xfopen_for_read("/proc/net/arp");
418 /* Bypass header -- read one line */
419 fgets(line, sizeof(line), fp);
421 /* Read the ARP cache entries. */
422 while (fgets(line, sizeof(line), fp)) {
424 mask[0] = '-'; mask[1] = '\0';
425 dev[0] = '-'; dev[1] = '\0';
426 /* All these strings can't overflow
427 * because fgets above reads limited amount of data */
428 num = sscanf(line, "%s 0x%x 0x%x %s %s %s\n",
429 ip, &type, &flags, hwa, mask, dev);
434 /* if the user specified hw-type differs, skip it */
435 if (hw_set && (type != hw->type))
438 /* if the user specified address differs, skip it */
439 if (host && strcmp(ip, host) != 0)
442 /* if the user specified device differs, skip it */
443 if (device[0] && strcmp(dev, device) != 0)
447 /* This IS ugly but it works -be */
449 if (!(option_mask32 & ARP_OPT_n)) {
450 if (ap->input(ip, &sa) < 0)
453 hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) | 0x8000);
454 if (strcmp(hostname, ip) == 0)
458 arp_disp(hostname, ip, type, flags, hwa, mask, dev);
460 if (option_mask32 & ARP_OPT_v)
461 printf("Entries: %u\tSkipped: %u\tFound: %u\n",
462 entries, entries - shown, shown);
465 if (hw_set || host || device[0])
466 printf("No match found in %u entries\n", entries);
468 if (ENABLE_FEATURE_CLEAN_UP) {
475 int arp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
476 int arp_main(int argc UNUSED_PARAM, char **argv)
479 const char *protocol;
484 xmove_fd(xsocket(AF_INET, SOCK_DGRAM, 0), sockfd);
486 ap = get_aftype(DFLT_AF);
487 /* Defaults are always supported */
489 // bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family");
490 hw = get_hwtype(DFLT_HW);
492 // bb_error_msg_and_die("%s: %s not supported", DFLT_HW, "hardware type");
494 opts = getopt32(argv, "A:p:H:t:i:adnDsv", &protocol, &protocol,
495 &hw_type, &hw_type, &device);
497 if (opts & (ARP_OPT_A | ARP_OPT_p)) {
498 ap = get_aftype(protocol);
500 bb_error_msg_and_die("%s: unknown %s", protocol, "address family");
502 if (opts & (ARP_OPT_H | ARP_OPT_t)) {
503 hw = get_hwtype(hw_type);
505 bb_error_msg_and_die("%s: unknown %s", hw_type, "hardware type");
508 //if (opts & ARP_OPT_i)... -i
510 if (ap->af != AF_INET) {
511 bb_error_msg_and_die("%s: kernel only supports 'inet'", ap->name);
514 bb_error_msg_and_die("%s: %s without ARP support",
515 hw->name, "hardware type");
518 /* Now see what we have to do here... */
519 if (opts & (ARP_OPT_d | ARP_OPT_s)) {
521 bb_error_msg_and_die("need host name");
522 if (opts & ARP_OPT_s)
523 return arp_set(argv);
524 return arp_del(argv);
527 //if (opts & ARP_OPT_a) - default
528 return arp_show(argv[0]);