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>
17 #include "inet_common.h"
19 #include <arpa/inet.h>
21 #include <net/if_arp.h>
22 #include <netinet/ether.h>
23 #include <netpacket/packet.h>
27 #define DFLT_AF "inet"
28 #define DFLT_HW "ether"
38 ARP_OPT_n
= (1 << 7), /* do not resolve addresses */
39 ARP_OPT_D
= (1 << 8), /* HW-address is devicename */
41 ARP_OPT_v
= (1 << 10) * DEBUG
, /* debugging output flag */
45 sockfd
= 3, /* active socket descriptor */
49 const struct aftype
*ap
; /* current address family */
50 const struct hwtype
*hw
; /* current hardware type */
51 const char *device
; /* current device */
52 smallint hw_set
; /* flag if hw-type was set (-H) */
55 #define G (*(struct globals*)&bb_common_bufsiz1)
58 #define device (G.device )
59 #define hw_set (G.hw_set )
60 #define INIT_G() do { \
65 static const char options
[] ALIGN1
=
75 /* Delete an entry from the ARP cache. */
76 /* Called only from main, once */
77 static int arp_del(char **args
)
85 memset(&req
, 0, sizeof(req
));
87 /* Resolve the host name. */
89 if (ap
->input(host
, &sa
) < 0) {
90 bb_herror_msg_and_die("%s", host
);
93 /* If a host has more than one address, use the correct one! */
94 memcpy(&req
.arp_pa
, &sa
, sizeof(struct sockaddr
));
97 req
.arp_ha
.sa_family
= hw
->type
;
99 req
.arp_flags
= ATF_PERM
;
101 while (*args
!= NULL
) {
102 switch (index_in_strings(options
, *args
)) {
112 req
.arp_flags
&= ~ATF_PERM
;
115 case 3: /* "trail" */
116 req
.arp_flags
|= ATF_USETRAILERS
;
119 case 4: /* "dontpub" */
120 #ifdef HAVE_ATF_DONTPUB
121 req
.arp_flags
|= ATF_DONTPUB
;
123 bb_error_msg("feature ATF_DONTPUB is not supported");
128 #ifdef HAVE_ATF_MAGIC
129 req
.arp_flags
|= ATF_MAGIC
;
131 bb_error_msg("feature ATF_MAGIC is not supported");
141 case 7: /* "netmask" */
144 if (strcmp(*args
, "255.255.255.255") != 0) {
146 if (ap
->input(host
, &sa
) < 0) {
147 bb_herror_msg_and_die("%s", host
);
149 memcpy(&req
.arp_netmask
, &sa
, sizeof(struct sockaddr
));
150 req
.arp_flags
|= ATF_NETMASK
;
162 strncpy(req
.arp_dev
, device
, sizeof(req
.arp_dev
));
166 /* Call the kernel. */
168 if (option_mask32
& ARP_OPT_v
)
169 bb_error_msg("SIOCDARP(nopub)");
170 err
= ioctl(sockfd
, SIOCDARP
, &req
);
172 if (errno
== ENXIO
) {
175 printf("No ARP entry for %s\n", host
);
178 bb_perror_msg_and_die("SIOCDARP(priv)");
181 if ((flags
& 1) && err
) {
183 req
.arp_flags
|= ATF_PUBL
;
184 if (option_mask32
& ARP_OPT_v
)
185 bb_error_msg("SIOCDARP(pub)");
186 if (ioctl(sockfd
, SIOCDARP
, &req
) < 0) {
187 if (errno
== ENXIO
) {
188 printf("No ARP entry for %s\n", host
);
191 bb_perror_msg_and_die("SIOCDARP(pub)");
197 /* Get the hardware address to a specified interface name */
198 static void arp_getdevhw(char *ifname
, struct sockaddr
*sa
,
199 const struct hwtype
*hwt
)
202 const struct hwtype
*xhw
;
204 strcpy(ifr
.ifr_name
, ifname
);
205 ioctl_or_perror_and_die(sockfd
, SIOCGIFHWADDR
, &ifr
,
206 "cant get HW-Address for '%s'", ifname
);
207 if (hwt
&& (ifr
.ifr_hwaddr
.sa_family
!= hw
->type
)) {
208 bb_error_msg_and_die("protocol type mismatch");
210 memcpy(sa
, &(ifr
.ifr_hwaddr
), sizeof(struct sockaddr
));
212 if (option_mask32
& ARP_OPT_v
) {
213 xhw
= get_hwntype(ifr
.ifr_hwaddr
.sa_family
);
214 if (!xhw
|| !xhw
->print
) {
215 xhw
= get_hwntype(-1);
217 bb_error_msg("device '%s' has HW address %s '%s'",
219 xhw
->print((unsigned char *) &ifr
.ifr_hwaddr
.sa_data
));
223 /* Set an entry in the ARP cache. */
224 /* Called only from main, once */
225 static int arp_set(char **args
)
232 memset(&req
, 0, sizeof(req
));
235 if (ap
->input(host
, &sa
) < 0) {
236 bb_herror_msg_and_die("%s", host
);
238 /* If a host has more than one address, use the correct one! */
239 memcpy(&req
.arp_pa
, &sa
, sizeof(struct sockaddr
));
241 /* Fetch the hardware address. */
243 bb_error_msg_and_die("need hardware address");
245 if (option_mask32
& ARP_OPT_D
) {
246 arp_getdevhw(*args
++, &req
.arp_ha
, hw_set
? hw
: NULL
);
248 if (hw
->input(*args
++, &req
.arp_ha
) < 0) {
249 bb_error_msg_and_die("invalid hardware address");
253 /* Check out any modifiers. */
254 flags
= ATF_PERM
| ATF_COM
;
255 while (*args
!= NULL
) {
256 switch (index_in_strings(options
, *args
)) {
269 case 3: /* "trail" */
270 flags
|= ATF_USETRAILERS
;
273 case 4: /* "dontpub" */
274 #ifdef HAVE_ATF_DONTPUB
275 flags
|= ATF_DONTPUB
;
277 bb_error_msg("feature ATF_DONTPUB is not supported");
282 #ifdef HAVE_ATF_MAGIC
285 bb_error_msg("feature ATF_MAGIC is not supported");
295 case 7: /* "netmask" */
298 if (strcmp(*args
, "255.255.255.255") != 0) {
300 if (ap
->input(host
, &sa
) < 0) {
301 bb_herror_msg_and_die("%s", host
);
303 memcpy(&req
.arp_netmask
, &sa
, sizeof(struct sockaddr
));
304 flags
|= ATF_NETMASK
;
314 /* Fill in the remainder of the request. */
315 req
.arp_flags
= flags
;
317 strncpy(req
.arp_dev
, device
, sizeof(req
.arp_dev
));
319 /* Call the kernel. */
320 if (option_mask32
& ARP_OPT_v
)
321 bb_error_msg("SIOCSARP()");
322 xioctl(sockfd
, SIOCSARP
, &req
);
327 /* Print the contents of an ARP request block. */
329 arp_disp(const char *name
, char *ip
, int type
, int arp_flags
,
330 char *hwa
, char *mask
, char *dev
)
332 static const int arp_masks
[] = {
334 #ifdef HAVE_ATF_MAGIC
337 #ifdef HAVE_ATF_DONTPUB
342 static const char arp_labels
[] ALIGN1
= "PERM\0""PUP\0"
343 #ifdef HAVE_ATF_MAGIC
346 #ifdef HAVE_ATF_DONTPUB
352 const struct hwtype
*xhw
;
354 xhw
= get_hwntype(type
);
356 xhw
= get_hwtype(DFLT_HW
);
358 printf("%s (%s) at ", name
, ip
);
360 if (!(arp_flags
& ATF_COM
)) {
361 if (arp_flags
& ATF_PUBL
)
364 printf("<incomplete> ");
366 printf("%s [%s] ", hwa
, xhw
->name
);
369 if (arp_flags
& ATF_NETMASK
)
370 printf("netmask %s ", mask
);
372 print_flags_separated(arp_masks
, arp_labels
, arp_flags
, " ");
373 printf(" on %s\n", dev
);
376 /* Display the contents of the ARP cache in the kernel. */
377 /* Called only from main, once */
378 static int arp_show(char *name
)
381 const char *hostname
;
386 unsigned entries
= 0, shown
= 0;
395 /* Resolve the host name. */
396 if (ap
->input(name
, &sa
) < 0) {
397 bb_herror_msg_and_die("%s", name
);
399 host
= xstrdup(ap
->sprint(&sa
, 1));
401 fp
= xfopen_for_read("/proc/net/arp");
402 /* Bypass header -- read one line */
403 fgets(line
, sizeof(line
), fp
);
405 /* Read the ARP cache entries. */
406 while (fgets(line
, sizeof(line
), fp
)) {
408 mask
[0] = '-'; mask
[1] = '\0';
409 dev
[0] = '-'; dev
[1] = '\0';
410 /* All these strings can't overflow
411 * because fgets above reads limited amount of data */
412 num
= sscanf(line
, "%s 0x%x 0x%x %s %s %s\n",
413 ip
, &type
, &flags
, hwa
, mask
, dev
);
418 /* if the user specified hw-type differs, skip it */
419 if (hw_set
&& (type
!= hw
->type
))
422 /* if the user specified address differs, skip it */
423 if (host
&& strcmp(ip
, host
) != 0)
426 /* if the user specified device differs, skip it */
427 if (device
[0] && strcmp(dev
, device
) != 0)
431 /* This IS ugly but it works -be */
433 if (!(option_mask32
& ARP_OPT_n
)) {
434 if (ap
->input(ip
, &sa
) < 0)
437 hostname
= ap
->sprint(&sa
, (option_mask32
& ARP_OPT_n
) | 0x8000);
438 if (strcmp(hostname
, ip
) == 0)
442 arp_disp(hostname
, ip
, type
, flags
, hwa
, mask
, dev
);
444 if (option_mask32
& ARP_OPT_v
)
445 printf("Entries: %d\tSkipped: %d\tFound: %d\n",
446 entries
, entries
- shown
, shown
);
449 if (hw_set
|| host
|| device
[0])
450 printf("No match found in %d entries\n", entries
);
452 if (ENABLE_FEATURE_CLEAN_UP
) {
459 int arp_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
460 int arp_main(int argc UNUSED_PARAM
, char **argv
)
462 const char *hw_type
= "ether";
463 const char *protocol
;
468 xmove_fd(xsocket(AF_INET
, SOCK_DGRAM
, 0), sockfd
);
469 ap
= get_aftype(DFLT_AF
);
471 bb_error_msg_and_die("%s: %s not supported", DFLT_AF
, "address family");
473 opts
= getopt32(argv
, "A:p:H:t:i:adnDsv", &protocol
, &protocol
,
474 &hw_type
, &hw_type
, &device
);
476 if (opts
& (ARP_OPT_A
| ARP_OPT_p
)) {
477 ap
= get_aftype(protocol
);
479 bb_error_msg_and_die("%s: unknown %s", protocol
, "address family");
481 if (opts
& (ARP_OPT_A
| ARP_OPT_p
)) {
482 hw
= get_hwtype(hw_type
);
484 bb_error_msg_and_die("%s: unknown %s", hw_type
, "hardware type");
487 //if (opts & ARP_OPT_i)... -i
489 if (ap
->af
!= AF_INET
) {
490 bb_error_msg_and_die("%s: kernel only supports 'inet'", ap
->name
);
493 /* If no hw type specified get default */
495 hw
= get_hwtype(DFLT_HW
);
497 bb_error_msg_and_die("%s: %s not supported", DFLT_HW
, "hardware type");
501 bb_error_msg_and_die("%s: %s without ARP support",
502 hw
->name
, "hardware type");
505 /* Now see what we have to do here... */
506 if (opts
& (ARP_OPT_d
| ARP_OPT_s
)) {
508 bb_error_msg_and_die("need host name");
509 if (opts
& ARP_OPT_s
)
510 return arp_set(argv
);
511 return arp_del(argv
);
513 //if (opts & ARP_OPT_a) - default
514 return arp_show(argv
[0]);