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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//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"
33
34#include "libbb.h"
35#include "inet_common.h"
36
37#include <arpa/inet.h>
38#include <net/if.h>
39#include <net/if_arp.h>
40#include <netinet/ether.h>
41#include <netpacket/packet.h>
42
43#define DEBUG 0
44
45#define DFLT_AF "inet"
46#define DFLT_HW "ether"
47
48enum {
49 ARP_OPT_A = (1 << 0),
50 ARP_OPT_p = (1 << 1),
51 ARP_OPT_H = (1 << 2),
52 ARP_OPT_t = (1 << 3),
53 ARP_OPT_i = (1 << 4),
54 ARP_OPT_a = (1 << 5),
55 ARP_OPT_d = (1 << 6),
56 ARP_OPT_n = (1 << 7), /* do not resolve addresses */
57 ARP_OPT_D = (1 << 8), /* HW-address is devicename */
58 ARP_OPT_s = (1 << 9),
59 ARP_OPT_v = (1 << 10) * DEBUG, /* debugging output flag */
60};
61
62enum {
63 sockfd = 3, /* active socket descriptor */
64};
65
66struct globals {
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) */
71
72} FIX_ALIASING;
73#define G (*(struct globals*)&bb_common_bufsiz1)
74#define ap (G.ap )
75#define hw (G.hw )
76#define device (G.device )
77#define hw_set (G.hw_set )
78#define INIT_G() do { \
79 device = ""; \
80} while (0)
81
82
83static const char options[] ALIGN1 =
84 "pub\0"
85 "priv\0"
86 "temp\0"
87 "trail\0"
88 "dontpub\0"
89 "auto\0"
90 "dev\0"
91 "netmask\0";
92
93/* Delete an entry from the ARP cache. */
94/* Called only from main, once */
95static int arp_del(char **args)
96{
97 char *host;
98 struct arpreq req;
99 struct sockaddr sa;
100 int flags = 0;
101 int err;
102
103 memset(&req, 0, sizeof(req));
104
105 /* Resolve the host name. */
106 host = *args;
107 if (ap->input(host, &sa) < 0) {
108 bb_herror_msg_and_die("%s", host);
109 }
110
111 /* If a host has more than one address, use the correct one! */
112 memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
113
114 if (hw_set)
115 req.arp_ha.sa_family = hw->type;
116
117 req.arp_flags = ATF_PERM;
118 args++;
119 while (*args != NULL) {
120 switch (index_in_strings(options, *args)) {
121 case 0: /* "pub" */
122 flags |= 1;
123 args++;
124 break;
125 case 1: /* "priv" */
126 flags |= 2;
127 args++;
128 break;
129 case 2: /* "temp" */
130 req.arp_flags &= ~ATF_PERM;
131 args++;
132 break;
133 case 3: /* "trail" */
134 req.arp_flags |= ATF_USETRAILERS;
135 args++;
136 break;
137 case 4: /* "dontpub" */
138#ifdef HAVE_ATF_DONTPUB
139 req.arp_flags |= ATF_DONTPUB;
140#else
141 bb_error_msg("feature ATF_DONTPUB is not supported");
142#endif
143 args++;
144 break;
145 case 5: /* "auto" */
146#ifdef HAVE_ATF_MAGIC
147 req.arp_flags |= ATF_MAGIC;
148#else
149 bb_error_msg("feature ATF_MAGIC is not supported");
150#endif
151 args++;
152 break;
153 case 6: /* "dev" */
154 if (*++args == NULL)
155 bb_show_usage();
156 device = *args;
157 args++;
158 break;
159 case 7: /* "netmask" */
160 if (*++args == NULL)
161 bb_show_usage();
162 if (strcmp(*args, "255.255.255.255") != 0) {
163 host = *args;
164 if (ap->input(host, &sa) < 0) {
165 bb_herror_msg_and_die("%s", host);
166 }
167 memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
168 req.arp_flags |= ATF_NETMASK;
169 }
170 args++;
171 break;
172 default:
173 bb_show_usage();
174 break;
175 }
176 }
177 if (flags == 0)
178 flags = 3;
179
180 strncpy(req.arp_dev, device, sizeof(req.arp_dev));
181
182 err = -1;
183
184 /* Call the kernel. */
185 if (flags & 2) {
186 if (option_mask32 & ARP_OPT_v)
187 bb_error_msg("SIOCDARP(nopub)");
188 err = ioctl(sockfd, SIOCDARP, &req);
189 if (err < 0) {
190 if (errno == ENXIO) {
191 if (flags & 1)
192 goto nopub;
193 printf("No ARP entry for %s\n", host);
194 return -1;
195 }
196 bb_perror_msg_and_die("SIOCDARP(priv)");
197 }
198 }
199 if ((flags & 1) && err) {
200 nopub:
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);
207 return -1;
208 }
209 bb_perror_msg_and_die("SIOCDARP(pub)");
210 }
211 }
212 return 0;
213}
214
215/* Get the hardware address to a specified interface name */
216static void arp_getdevhw(char *ifname, struct sockaddr *sa)
217{
218 struct ifreq ifr;
219 const struct hwtype *xhw;
220
221 strcpy(ifr.ifr_name, ifname);
222 ioctl_or_perror_and_die(sockfd, SIOCGIFHWADDR, &ifr,
223 "can't get HW-Address for '%s'", ifname);
224 if (hw_set && (ifr.ifr_hwaddr.sa_family != hw->type)) {
225 bb_error_msg_and_die("protocol type mismatch");
226 }
227 memcpy(sa, &(ifr.ifr_hwaddr), sizeof(struct sockaddr));
228
229 if (option_mask32 & ARP_OPT_v) {
230 xhw = get_hwntype(ifr.ifr_hwaddr.sa_family);
231 if (!xhw || !xhw->print) {
232 xhw = get_hwntype(-1);
233 }
234 bb_error_msg("device '%s' has HW address %s '%s'",
235 ifname, xhw->name,
236 xhw->print((unsigned char *) &ifr.ifr_hwaddr.sa_data));
237 }
238}
239
240/* Set an entry in the ARP cache. */
241/* Called only from main, once */
242static int arp_set(char **args)
243{
244 char *host;
245 struct arpreq req;
246 struct sockaddr sa;
247 int flags;
248
249 memset(&req, 0, sizeof(req));
250
251 host = *args++;
252 if (ap->input(host, &sa) < 0) {
253 bb_herror_msg_and_die("%s", host);
254 }
255 /* If a host has more than one address, use the correct one! */
256 memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
257
258 /* Fetch the hardware address. */
259 if (*args == NULL) {
260 bb_error_msg_and_die("need hardware address");
261 }
262 if (option_mask32 & ARP_OPT_D) {
263 arp_getdevhw(*args++, &req.arp_ha);
264 } else {
265 if (hw->input(*args++, &req.arp_ha) < 0) {
266 bb_error_msg_and_die("invalid hardware address");
267 }
268 }
269
270 /* Check out any modifiers. */
271 flags = ATF_PERM | ATF_COM;
272 while (*args != NULL) {
273 switch (index_in_strings(options, *args)) {
274 case 0: /* "pub" */
275 flags |= ATF_PUBL;
276 args++;
277 break;
278 case 1: /* "priv" */
279 flags &= ~ATF_PUBL;
280 args++;
281 break;
282 case 2: /* "temp" */
283 flags &= ~ATF_PERM;
284 args++;
285 break;
286 case 3: /* "trail" */
287 flags |= ATF_USETRAILERS;
288 args++;
289 break;
290 case 4: /* "dontpub" */
291#ifdef HAVE_ATF_DONTPUB
292 flags |= ATF_DONTPUB;
293#else
294 bb_error_msg("feature ATF_DONTPUB is not supported");
295#endif
296 args++;
297 break;
298 case 5: /* "auto" */
299#ifdef HAVE_ATF_MAGIC
300 flags |= ATF_MAGIC;
301#else
302 bb_error_msg("feature ATF_MAGIC is not supported");
303#endif
304 args++;
305 break;
306 case 6: /* "dev" */
307 if (*++args == NULL)
308 bb_show_usage();
309 device = *args;
310 args++;
311 break;
312 case 7: /* "netmask" */
313 if (*++args == NULL)
314 bb_show_usage();
315 if (strcmp(*args, "255.255.255.255") != 0) {
316 host = *args;
317 if (ap->input(host, &sa) < 0) {
318 bb_herror_msg_and_die("%s", host);
319 }
320 memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
321 flags |= ATF_NETMASK;
322 }
323 args++;
324 break;
325 default:
326 bb_show_usage();
327 break;
328 }
329 }
330
331 /* Fill in the remainder of the request. */
332 req.arp_flags = flags;
333
334 strncpy(req.arp_dev, device, sizeof(req.arp_dev));
335
336 /* Call the kernel. */
337 if (option_mask32 & ARP_OPT_v)
338 bb_error_msg("SIOCSARP()");
339 xioctl(sockfd, SIOCSARP, &req);
340 return 0;
341}
342
343
344/* Print the contents of an ARP request block. */
345static void
346arp_disp(const char *name, char *ip, int type, int arp_flags,
347 char *hwa, char *mask, char *dev)
348{
349 static const int arp_masks[] = {
350 ATF_PERM, ATF_PUBL,
351#ifdef HAVE_ATF_MAGIC
352 ATF_MAGIC,
353#endif
354#ifdef HAVE_ATF_DONTPUB
355 ATF_DONTPUB,
356#endif
357 ATF_USETRAILERS,
358 };
359 static const char arp_labels[] ALIGN1 = "PERM\0""PUP\0"
360#ifdef HAVE_ATF_MAGIC
361 "AUTO\0"
362#endif
363#ifdef HAVE_ATF_DONTPUB
364 "DONTPUB\0"
365#endif
366 "TRAIL\0"
367 ;
368
369 const struct hwtype *xhw;
370
371 xhw = get_hwntype(type);
372 if (xhw == NULL)
373 xhw = get_hwtype(DFLT_HW);
374
375 printf("%s (%s) at ", name, ip);
376
377 if (!(arp_flags & ATF_COM)) {
378 if (arp_flags & ATF_PUBL)
379 printf("* ");
380 else
381 printf("<incomplete> ");
382 } else {
383 printf("%s [%s] ", hwa, xhw->name);
384 }
385
386 if (arp_flags & ATF_NETMASK)
387 printf("netmask %s ", mask);
388
389 print_flags_separated(arp_masks, arp_labels, arp_flags, " ");
390 printf(" on %s\n", dev);
391}
392
393/* Display the contents of the ARP cache in the kernel. */
394/* Called only from main, once */
395static int arp_show(char *name)
396{
397 const char *host;
398 const char *hostname;
399 FILE *fp;
400 struct sockaddr sa;
401 int type, flags;
402 int num;
403 unsigned entries = 0, shown = 0;
404 char ip[128];
405 char hwa[128];
406 char mask[128];
407 char line[128];
408 char dev[128];
409
410 host = NULL;
411 if (name != NULL) {
412 /* Resolve the host name. */
413 if (ap->input(name, &sa) < 0) {
414 bb_herror_msg_and_die("%s", name);
415 }
416 host = xstrdup(ap->sprint(&sa, 1));
417 }
418 fp = xfopen_for_read("/proc/net/arp");
419 /* Bypass header -- read one line */
420 fgets(line, sizeof(line), fp);
421
422 /* Read the ARP cache entries. */
423 while (fgets(line, sizeof(line), fp)) {
424
425 mask[0] = '-'; mask[1] = '\0';
426 dev[0] = '-'; dev[1] = '\0';
427 /* All these strings can't overflow
428 * because fgets above reads limited amount of data */
429 num = sscanf(line, "%s 0x%x 0x%x %s %s %s\n",
430 ip, &type, &flags, hwa, mask, dev);
431 if (num < 4)
432 break;
433
434 entries++;
435 /* if the user specified hw-type differs, skip it */
436 if (hw_set && (type != hw->type))
437 continue;
438
439 /* if the user specified address differs, skip it */
440 if (host && strcmp(ip, host) != 0)
441 continue;
442
443 /* if the user specified device differs, skip it */
444 if (device[0] && strcmp(dev, device) != 0)
445 continue;
446
447 shown++;
448 /* This IS ugly but it works -be */
449 hostname = "?";
450 if (!(option_mask32 & ARP_OPT_n)) {
451 if (ap->input(ip, &sa) < 0)
452 hostname = ip;
453 else
454 hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) | 0x8000);
455 if (strcmp(hostname, ip) == 0)
456 hostname = "?";
457 }
458
459 arp_disp(hostname, ip, type, flags, hwa, mask, dev);
460 }
461 if (option_mask32 & ARP_OPT_v)
462 printf("Entries: %u\tSkipped: %u\tFound: %u\n",
463 entries, entries - shown, shown);
464
465 if (!shown) {
466 if (hw_set || host || device[0])
467 printf("No match found in %u entries\n", entries);
468 }
469 if (ENABLE_FEATURE_CLEAN_UP) {
470 free((char*)host);
471 fclose(fp);
472 }
473 return 0;
474}
475
476int arp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
477int arp_main(int argc UNUSED_PARAM, char **argv)
478{
479 const char *hw_type;
480 const char *protocol;
481 unsigned opts;
482
483 INIT_G();
484
485 xmove_fd(xsocket(AF_INET, SOCK_DGRAM, 0), sockfd);
486
487 ap = get_aftype(DFLT_AF);
488 /* Defaults are always supported */
489 //if (!ap)
490 // bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family");
491 hw = get_hwtype(DFLT_HW);
492 //if (!hw)
493 // bb_error_msg_and_die("%s: %s not supported", DFLT_HW, "hardware type");
494
495 opts = getopt32(argv, "A:p:H:t:i:adnDsv", &protocol, &protocol,
496 &hw_type, &hw_type, &device);
497 argv += optind;
498 if (opts & (ARP_OPT_A | ARP_OPT_p)) {
499 ap = get_aftype(protocol);
500 if (!ap)
501 bb_error_msg_and_die("%s: unknown %s", protocol, "address family");
502 }
503 if (opts & (ARP_OPT_H | ARP_OPT_t)) {
504 hw = get_hwtype(hw_type);
505 if (!hw)
506 bb_error_msg_and_die("%s: unknown %s", hw_type, "hardware type");
507 hw_set = 1;
508 }
509 //if (opts & ARP_OPT_i)... -i
510
511 if (ap->af != AF_INET) {
512 bb_error_msg_and_die("%s: kernel only supports 'inet'", ap->name);
513 }
514 if (hw->alen <= 0) {
515 bb_error_msg_and_die("%s: %s without ARP support",
516 hw->name, "hardware type");
517 }
518
519 /* Now see what we have to do here... */
520 if (opts & (ARP_OPT_d | ARP_OPT_s)) {
521 if (argv[0] == NULL)
522 bb_error_msg_and_die("need host name");
523 if (opts & ARP_OPT_s)
524 return arp_set(argv);
525 return arp_del(argv);
526 }
527
528 //if (opts & ARP_OPT_a) - default
529 return arp_show(argv[0]);
530}
531
generated by cgit at 2024-05-15 15:33:01 (GMT)