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 -s Set new ARP entry"
26 //usage: "\n -d Delete a specified 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 given device"
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) */
73 #define G (*(struct globals*)&bb_common_bufsiz1)
76 #define device (G.device )
77 #define hw_set (G.hw_set )
78 #define INIT_G() do { \
83 static const char options
[] ALIGN1
=
93 /* Delete an entry from the ARP cache. */
94 /* Called only from main, once */
95 static int arp_del(char **args
)
103 memset(&req
, 0, sizeof(req
));
105 /* Resolve the host name. */
107 if (ap
->input(host
, &sa
) < 0) {
108 bb_herror_msg_and_die("%s", host
);
111 /* If a host has more than one address, use the correct one! */
112 memcpy(&req
.arp_pa
, &sa
, sizeof(struct sockaddr
));
115 req
.arp_ha
.sa_family
= hw
->type
;
117 req
.arp_flags
= ATF_PERM
;
119 while (*args
!= NULL
) {
120 switch (index_in_strings(options
, *args
)) {
130 req
.arp_flags
&= ~ATF_PERM
;
133 case 3: /* "trail" */
134 req
.arp_flags
|= ATF_USETRAILERS
;
137 case 4: /* "dontpub" */
138 #ifdef HAVE_ATF_DONTPUB
139 req
.arp_flags
|= ATF_DONTPUB
;
141 bb_error_msg("feature ATF_DONTPUB is not supported");
146 #ifdef HAVE_ATF_MAGIC
147 req
.arp_flags
|= ATF_MAGIC
;
149 bb_error_msg("feature ATF_MAGIC is not supported");
159 case 7: /* "netmask" */
162 if (strcmp(*args
, "255.255.255.255") != 0) {
164 if (ap
->input(host
, &sa
) < 0) {
165 bb_herror_msg_and_die("%s", host
);
167 memcpy(&req
.arp_netmask
, &sa
, sizeof(struct sockaddr
));
168 req
.arp_flags
|= ATF_NETMASK
;
180 strncpy(req
.arp_dev
, device
, sizeof(req
.arp_dev
));
184 /* Call the kernel. */
186 if (option_mask32
& ARP_OPT_v
)
187 bb_error_msg("SIOCDARP(nopub)");
188 err
= ioctl(sockfd
, SIOCDARP
, &req
);
190 if (errno
== ENXIO
) {
193 printf("No ARP entry for %s\n", host
);
196 bb_perror_msg_and_die("SIOCDARP(priv)");
199 if ((flags
& 1) && err
) {
201 req
.arp_flags
|= ATF_PUBL
;
202 if (option_mask32
& ARP_OPT_v
)
203 bb_error_msg("SIOCDARP(pub)");
204 if (ioctl(sockfd
, SIOCDARP
, &req
) < 0) {
205 if (errno
== ENXIO
) {
206 printf("No ARP entry for %s\n", host
);
209 bb_perror_msg_and_die("SIOCDARP(pub)");
215 /* Get the hardware address to a specified interface name */
216 static void arp_getdevhw(char *ifname
, struct sockaddr
*sa
,
217 const struct hwtype
*hwt
)
220 const struct hwtype
*xhw
;
222 strcpy(ifr
.ifr_name
, ifname
);
223 ioctl_or_perror_and_die(sockfd
, SIOCGIFHWADDR
, &ifr
,
224 "cant get HW-Address for '%s'", ifname
);
225 if (hwt
&& (ifr
.ifr_hwaddr
.sa_family
!= hw
->type
)) {
226 bb_error_msg_and_die("protocol type mismatch");
228 memcpy(sa
, &(ifr
.ifr_hwaddr
), sizeof(struct sockaddr
));
230 if (option_mask32
& ARP_OPT_v
) {
231 xhw
= get_hwntype(ifr
.ifr_hwaddr
.sa_family
);
232 if (!xhw
|| !xhw
->print
) {
233 xhw
= get_hwntype(-1);
235 bb_error_msg("device '%s' has HW address %s '%s'",
237 xhw
->print((unsigned char *) &ifr
.ifr_hwaddr
.sa_data
));
241 /* Set an entry in the ARP cache. */
242 /* Called only from main, once */
243 static int arp_set(char **args
)
250 memset(&req
, 0, sizeof(req
));
253 if (ap
->input(host
, &sa
) < 0) {
254 bb_herror_msg_and_die("%s", host
);
256 /* If a host has more than one address, use the correct one! */
257 memcpy(&req
.arp_pa
, &sa
, sizeof(struct sockaddr
));
259 /* Fetch the hardware address. */
261 bb_error_msg_and_die("need hardware address");
263 if (option_mask32
& ARP_OPT_D
) {
264 arp_getdevhw(*args
++, &req
.arp_ha
, hw_set
? hw
: NULL
);
266 if (hw
->input(*args
++, &req
.arp_ha
) < 0) {
267 bb_error_msg_and_die("invalid hardware address");
271 /* Check out any modifiers. */
272 flags
= ATF_PERM
| ATF_COM
;
273 while (*args
!= NULL
) {
274 switch (index_in_strings(options
, *args
)) {
287 case 3: /* "trail" */
288 flags
|= ATF_USETRAILERS
;
291 case 4: /* "dontpub" */
292 #ifdef HAVE_ATF_DONTPUB
293 flags
|= ATF_DONTPUB
;
295 bb_error_msg("feature ATF_DONTPUB is not supported");
300 #ifdef HAVE_ATF_MAGIC
303 bb_error_msg("feature ATF_MAGIC is not supported");
313 case 7: /* "netmask" */
316 if (strcmp(*args
, "255.255.255.255") != 0) {
318 if (ap
->input(host
, &sa
) < 0) {
319 bb_herror_msg_and_die("%s", host
);
321 memcpy(&req
.arp_netmask
, &sa
, sizeof(struct sockaddr
));
322 flags
|= ATF_NETMASK
;
332 /* Fill in the remainder of the request. */
333 req
.arp_flags
= flags
;
335 strncpy(req
.arp_dev
, device
, sizeof(req
.arp_dev
));
337 /* Call the kernel. */
338 if (option_mask32
& ARP_OPT_v
)
339 bb_error_msg("SIOCSARP()");
340 xioctl(sockfd
, SIOCSARP
, &req
);
345 /* Print the contents of an ARP request block. */
347 arp_disp(const char *name
, char *ip
, int type
, int arp_flags
,
348 char *hwa
, char *mask
, char *dev
)
350 static const int arp_masks
[] = {
352 #ifdef HAVE_ATF_MAGIC
355 #ifdef HAVE_ATF_DONTPUB
360 static const char arp_labels
[] ALIGN1
= "PERM\0""PUP\0"
361 #ifdef HAVE_ATF_MAGIC
364 #ifdef HAVE_ATF_DONTPUB
370 const struct hwtype
*xhw
;
372 xhw
= get_hwntype(type
);
374 xhw
= get_hwtype(DFLT_HW
);
376 printf("%s (%s) at ", name
, ip
);
378 if (!(arp_flags
& ATF_COM
)) {
379 if (arp_flags
& ATF_PUBL
)
382 printf("<incomplete> ");
384 printf("%s [%s] ", hwa
, xhw
->name
);
387 if (arp_flags
& ATF_NETMASK
)
388 printf("netmask %s ", mask
);
390 print_flags_separated(arp_masks
, arp_labels
, arp_flags
, " ");
391 printf(" on %s\n", dev
);
394 /* Display the contents of the ARP cache in the kernel. */
395 /* Called only from main, once */
396 static int arp_show(char *name
)
399 const char *hostname
;
404 unsigned entries
= 0, shown
= 0;
413 /* Resolve the host name. */
414 if (ap
->input(name
, &sa
) < 0) {
415 bb_herror_msg_and_die("%s", name
);
417 host
= xstrdup(ap
->sprint(&sa
, 1));
419 fp
= xfopen_for_read("/proc/net/arp");
420 /* Bypass header -- read one line */
421 fgets(line
, sizeof(line
), fp
);
423 /* Read the ARP cache entries. */
424 while (fgets(line
, sizeof(line
), fp
)) {
426 mask
[0] = '-'; mask
[1] = '\0';
427 dev
[0] = '-'; dev
[1] = '\0';
428 /* All these strings can't overflow
429 * because fgets above reads limited amount of data */
430 num
= sscanf(line
, "%s 0x%x 0x%x %s %s %s\n",
431 ip
, &type
, &flags
, hwa
, mask
, dev
);
436 /* if the user specified hw-type differs, skip it */
437 if (hw_set
&& (type
!= hw
->type
))
440 /* if the user specified address differs, skip it */
441 if (host
&& strcmp(ip
, host
) != 0)
444 /* if the user specified device differs, skip it */
445 if (device
[0] && strcmp(dev
, device
) != 0)
449 /* This IS ugly but it works -be */
451 if (!(option_mask32
& ARP_OPT_n
)) {
452 if (ap
->input(ip
, &sa
) < 0)
455 hostname
= ap
->sprint(&sa
, (option_mask32
& ARP_OPT_n
) | 0x8000);
456 if (strcmp(hostname
, ip
) == 0)
460 arp_disp(hostname
, ip
, type
, flags
, hwa
, mask
, dev
);
462 if (option_mask32
& ARP_OPT_v
)
463 printf("Entries: %d\tSkipped: %d\tFound: %d\n",
464 entries
, entries
- shown
, shown
);
467 if (hw_set
|| host
|| device
[0])
468 printf("No match found in %d entries\n", entries
);
470 if (ENABLE_FEATURE_CLEAN_UP
) {
477 int arp_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
478 int arp_main(int argc UNUSED_PARAM
, char **argv
)
480 const char *hw_type
= "ether";
481 const char *protocol
;
486 xmove_fd(xsocket(AF_INET
, SOCK_DGRAM
, 0), sockfd
);
487 ap
= get_aftype(DFLT_AF
);
489 bb_error_msg_and_die("%s: %s not supported", DFLT_AF
, "address family");
491 opts
= getopt32(argv
, "A:p:H:t:i:adnDsv", &protocol
, &protocol
,
492 &hw_type
, &hw_type
, &device
);
494 if (opts
& (ARP_OPT_A
| ARP_OPT_p
)) {
495 ap
= get_aftype(protocol
);
497 bb_error_msg_and_die("%s: unknown %s", protocol
, "address family");
499 if (opts
& (ARP_OPT_A
| ARP_OPT_p
)) {
500 hw
= get_hwtype(hw_type
);
502 bb_error_msg_and_die("%s: unknown %s", hw_type
, "hardware type");
505 //if (opts & ARP_OPT_i)... -i
507 if (ap
->af
!= AF_INET
) {
508 bb_error_msg_and_die("%s: kernel only supports 'inet'", ap
->name
);
511 /* If no hw type specified get default */
513 hw
= get_hwtype(DFLT_HW
);
515 bb_error_msg_and_die("%s: %s not supported", DFLT_HW
, "hardware type");
519 bb_error_msg_and_die("%s: %s without ARP support",
520 hw
->name
, "hardware type");
523 /* Now see what we have to do here... */
524 if (opts
& (ARP_OPT_d
| ARP_OPT_s
)) {
526 bb_error_msg_and_die("need host name");
527 if (opts
& ARP_OPT_s
)
528 return arp_set(argv
);
529 return arp_del(argv
);
531 //if (opts & ARP_OPT_a) - default
532 return arp_show(argv
[0]);