source: MondoRescue/branches/3.3/mindi-busybox/networking/arping.c@ 3621

Last change on this file since 3621 was 3621, checked in by Bruno Cornec, 7 years ago

New 3?3 banch for incorporation of latest busybox 1.25. Changing minor version to handle potential incompatibilities.
File size: 11.3 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
4 *
5 * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 * Busybox port: Nick Fedchik <nick@fedchik.org.ua>
7 */
8
9//usage:#define arping_trivial_usage
10//usage: "[-fqbDUA] [-c CNT] [-w TIMEOUT] [-I IFACE] [-s SRC_IP] DST_IP"
11//usage:#define arping_full_usage "\n\n"
12//usage: "Send ARP requests/replies\n"
13//usage: "\n -f Quit on first ARP reply"
14//usage: "\n -q Quiet"
15//usage: "\n -b Keep broadcasting, don't go unicast"
16//usage: "\n -D Exit with 1 if DST_IP replies"
17//usage: "\n -U Unsolicited ARP mode, update your neighbors"
18//usage: "\n -A ARP answer mode, update your neighbors"
19//usage: "\n -c N Stop after sending N ARP requests"
20//usage: "\n -w TIMEOUT Seconds to wait for ARP reply"
21//usage: "\n -I IFACE Interface to use (default eth0)"
22//usage: "\n -s SRC_IP Sender IP address"
23//usage: "\n DST_IP Target IP address"
24
25#include <arpa/inet.h>
26#include <net/if.h>
27#include <netinet/ether.h>
28#include <netpacket/packet.h>
29
30#include "libbb.h"
31#include "common_bufsiz.h"
32
33/* We don't expect to see 1000+ seconds delay, unsigned is enough */
34#define MONOTONIC_US() ((unsigned)monotonic_us())
35
36enum {
37 DAD = 1,
38 UNSOLICITED = 2,
39 ADVERT = 4,
40 QUIET = 8,
41 QUIT_ON_REPLY = 16,
42 BCAST_ONLY = 32,
43 UNICASTING = 64
44};
45
46struct globals {
47 struct in_addr src;
48 struct in_addr dst;
49 struct sockaddr_ll me;
50 struct sockaddr_ll he;
51 int sock_fd;
52
53 int count; // = -1;
54 unsigned last;
55 unsigned timeout_us;
56 unsigned start;
57
58 unsigned sent;
59 unsigned brd_sent;
60 unsigned received;
61 unsigned brd_recv;
62 unsigned req_recv;
63} FIX_ALIASING;
64#define G (*(struct globals*)bb_common_bufsiz1)
65#define src (G.src )
66#define dst (G.dst )
67#define me (G.me )
68#define he (G.he )
69#define sock_fd (G.sock_fd )
70#define count (G.count )
71#define last (G.last )
72#define timeout_us (G.timeout_us)
73#define start (G.start )
74#define sent (G.sent )
75#define brd_sent (G.brd_sent )
76#define received (G.received )
77#define brd_recv (G.brd_recv )
78#define req_recv (G.req_recv )
79#define INIT_G() do { \
80 setup_common_bufsiz(); \
81 count = -1; \
82} while (0)
83
84// If GNUisms are not available...
85//static void *mempcpy(void *_dst, const void *_src, int n)
86//{
87// memcpy(_dst, _src, n);
88// return (char*)_dst + n;
89//}
90
91static int send_pack(struct in_addr *src_addr,
92 struct in_addr *dst_addr, struct sockaddr_ll *ME,
93 struct sockaddr_ll *HE)
94{
95 int err;
96 unsigned char buf[256];
97 struct arphdr *ah = (struct arphdr *) buf;
98 unsigned char *p = (unsigned char *) (ah + 1);
99
100 ah->ar_hrd = htons(ARPHRD_ETHER);
101 ah->ar_pro = htons(ETH_P_IP);
102 ah->ar_hln = ME->sll_halen;
103 ah->ar_pln = 4;
104 ah->ar_op = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
105
106 p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
107 p = mempcpy(p, src_addr, 4);
108
109 if (option_mask32 & ADVERT)
110 p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
111 else
112 p = mempcpy(p, &HE->sll_addr, ah->ar_hln);
113
114 p = mempcpy(p, dst_addr, 4);
115
116 err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
117 if (err == p - buf) {
118 last = MONOTONIC_US();
119 sent++;
120 if (!(option_mask32 & UNICASTING))
121 brd_sent++;
122 }
123 return err;
124}
125
126static void finish(void) NORETURN;
127static void finish(void)
128{
129 if (!(option_mask32 & QUIET)) {
130 printf("Sent %u probe(s) (%u broadcast(s))\n"
131 "Received %u repl%s"
132 " (%u request(s), %u broadcast(s))\n",
133 sent, brd_sent,
134 received, (received == 1) ? "ies" : "y",
135 req_recv, brd_recv);
136 }
137 if (option_mask32 & DAD)
138 exit(!!received);
139 if (option_mask32 & UNSOLICITED)
140 exit(EXIT_SUCCESS);
141 exit(!received);
142}
143
144static void catcher(void)
145{
146 unsigned now;
147
148 now = MONOTONIC_US();
149 if (start == 0)
150 start = now;
151
152 if (count == 0 || (timeout_us && (now - start) > timeout_us))
153 finish();
154
155 /* count < 0 means "infinite count" */
156 if (count > 0)
157 count--;
158
159 if (last == 0 || (now - last) > 500000) {
160 send_pack(&src, &dst, &me, &he);
161 if (count == 0 && (option_mask32 & UNSOLICITED))
162 finish();
163 }
164 alarm(1);
165}
166
167static void recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
168{
169 struct arphdr *ah = (struct arphdr *) buf;
170 unsigned char *p = (unsigned char *) (ah + 1);
171 struct in_addr src_ip, dst_ip;
172 /* moves below assume in_addr is 4 bytes big, ensure that */
173 struct BUG_in_addr_must_be_4 {
174 char BUG_in_addr_must_be_4[
175 sizeof(struct in_addr) == 4 ? 1 : -1
176 ];
177 char BUG_s_addr_must_be_4[
178 sizeof(src_ip.s_addr) == 4 ? 1 : -1
179 ];
180 };
181
182 /* Filter out wild packets */
183 if (FROM->sll_pkttype != PACKET_HOST
184 && FROM->sll_pkttype != PACKET_BROADCAST
185 && FROM->sll_pkttype != PACKET_MULTICAST)
186 return;
187
188 /* Only these types are recognized */
189 if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
190 return;
191
192 /* ARPHRD check and this darned FDDI hack here :-( */
193 if (ah->ar_hrd != htons(FROM->sll_hatype)
194 && (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
195 return;
196
197 /* Protocol must be IP. */
198 if (ah->ar_pro != htons(ETH_P_IP)
199 || (ah->ar_pln != 4)
200 || (ah->ar_hln != me.sll_halen)
201 || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
202 return;
203
204 move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
205 move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);
206
207 if (dst.s_addr != src_ip.s_addr)
208 return;
209 if (!(option_mask32 & DAD)) {
210 if ((src.s_addr != dst_ip.s_addr)
211 || (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)))
212 return;
213 } else {
214 /* DAD packet was:
215 src_ip = 0 (or some src)
216 src_hw = ME
217 dst_ip = tested address
218 dst_hw = <unspec>
219
220 We fail, if receive request/reply with:
221 src_ip = tested_address
222 src_hw != ME
223 if src_ip in request was not zero, check
224 also that it matches to dst_ip, otherwise
225 dst_ip/dst_hw do not matter.
226 */
227 if ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
228 || (src.s_addr && src.s_addr != dst_ip.s_addr))
229 return;
230 }
231 if (!(option_mask32 & QUIET)) {
232 int s_printed = 0;
233
234 printf("%scast re%s from %s [%02x:%02x:%02x:%02x:%02x:%02x]",
235 FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
236 ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
237 inet_ntoa(src_ip),
238 p[0], p[1], p[2], p[3], p[4], p[5]
239 );
240 if (dst_ip.s_addr != src.s_addr) {
241 printf("for %s ", inet_ntoa(dst_ip));
242 s_printed = 1;
243 }
244 if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
245 unsigned char *pp = p + ah->ar_hln + 4;
246 if (!s_printed)
247 printf("for ");
248 printf("[%02x:%02x:%02x:%02x:%02x:%02x]",
249 pp[0], pp[1], pp[2], pp[3], pp[4], pp[5]
250 );
251 }
252
253 if (last) {
254 unsigned diff = MONOTONIC_US() - last;
255 printf(" %u.%03ums\n", diff / 1000, diff % 1000);
256 } else {
257 puts(" UNSOLICITED?");
258 }
259 fflush_all();
260 }
261 received++;
262 if (FROM->sll_pkttype != PACKET_HOST)
263 brd_recv++;
264 if (ah->ar_op == htons(ARPOP_REQUEST))
265 req_recv++;
266 if (option_mask32 & QUIT_ON_REPLY)
267 finish();
268 if (!(option_mask32 & BCAST_ONLY)) {
269 memcpy(he.sll_addr, p, me.sll_halen);
270 option_mask32 |= UNICASTING;
271 }
272}
273
274int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
275int arping_main(int argc UNUSED_PARAM, char **argv)
276{
277 const char *device = "eth0";
278 char *source = NULL;
279 char *target;
280 unsigned char *packet;
281 char *err_str;
282
283 INIT_G();
284
285 sock_fd = xsocket(AF_PACKET, SOCK_DGRAM, 0);
286
287 // Drop suid root privileges
288 // Need to remove SUID_NEVER from applets.h for this to work
289 //xsetuid(getuid());
290
291 {
292 unsigned opt;
293 char *str_timeout;
294
295 /* Dad also sets quit_on_reply.
296 * Advert also sets unsolicited.
297 */
298 opt_complementary = "=1:Df:AU:c+";
299 opt = getopt32(argv, "DUAqfbc:w:I:s:",
300 &count, &str_timeout, &device, &source);
301 if (opt & 0x80) /* -w: timeout */
302 timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000;
303 //if (opt & 0x200) /* -s: source */
304 option_mask32 &= 0x3f; /* set respective flags */
305 }
306
307 target = argv[optind];
308 err_str = xasprintf("interface %s %%s", device);
309 xfunc_error_retval = 2;
310
311 {
312 struct ifreq ifr;
313
314 memset(&ifr, 0, sizeof(ifr));
315 strncpy_IFNAMSIZ(ifr.ifr_name, device);
316 /* We use ifr.ifr_name in error msg so that problem
317 * with truncated name will be visible */
318 ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");
319 me.sll_ifindex = ifr.ifr_ifindex;
320
321 xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr);
322
323 if (!(ifr.ifr_flags & IFF_UP)) {
324 bb_error_msg_and_die(err_str, "is down");
325 }
326 if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
327 bb_error_msg(err_str, "is not ARPable");
328 return (option_mask32 & DAD ? 0 : 2);
329 }
330 }
331
332 /* if (!inet_aton(target, &dst)) - not needed */ {
333 len_and_sockaddr *lsa;
334 lsa = xhost_and_af2sockaddr(target, 0, AF_INET);
335 dst = lsa->u.sin.sin_addr;
336 if (ENABLE_FEATURE_CLEAN_UP)
337 free(lsa);
338 }
339
340 if (source && !inet_aton(source, &src)) {
341 bb_error_msg_and_die("invalid source address %s", source);
342 }
343
344 if ((option_mask32 & (DAD|UNSOLICITED)) == UNSOLICITED && src.s_addr == 0)
345 src = dst;
346
347 if (!(option_mask32 & DAD) || src.s_addr) {
348 struct sockaddr_in saddr;
349 int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
350
351 setsockopt_bindtodevice(probe_fd, device);
352 memset(&saddr, 0, sizeof(saddr));
353 saddr.sin_family = AF_INET;
354 if (src.s_addr) {
355 /* Check that this is indeed our IP */
356 saddr.sin_addr = src;
357 xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
358 } else { /* !(option_mask32 & DAD) case */
359 /* Find IP address on this iface */
360 socklen_t alen = sizeof(saddr);
361
362 saddr.sin_port = htons(1025);
363 saddr.sin_addr = dst;
364
365 if (setsockopt_SOL_SOCKET_1(probe_fd, SO_DONTROUTE) != 0)
366 bb_perror_msg("setsockopt(%s)", "SO_DONTROUTE");
367 xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
368 getsockname(probe_fd, (struct sockaddr *) &saddr, &alen);
369 //never happens:
370 //if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1)
371 // bb_perror_msg_and_die("getsockname");
372 if (saddr.sin_family != AF_INET)
373 bb_error_msg_and_die("no IP address configured");
374 src = saddr.sin_addr;
375 }
376 close(probe_fd);
377 }
378
379 me.sll_family = AF_PACKET;
380 //me.sll_ifindex = ifindex; - done before
381 me.sll_protocol = htons(ETH_P_ARP);
382 xbind(sock_fd, (struct sockaddr *) &me, sizeof(me));
383
384 {
385 socklen_t alen = sizeof(me);
386 getsockname(sock_fd, (struct sockaddr *) &me, &alen);
387 //never happens:
388 //if (getsockname(sock_fd, (struct sockaddr *) &me, &alen) == -1)
389 // bb_perror_msg_and_die("getsockname");
390 }
391 if (me.sll_halen == 0) {
392 bb_error_msg(err_str, "is not ARPable (no ll address)");
393 return (option_mask32 & DAD ? 0 : 2);
394 }
395 he = me;
396 memset(he.sll_addr, -1, he.sll_halen);
397
398 if (!(option_mask32 & QUIET)) {
399 /* inet_ntoa uses static storage, can't use in same printf */
400 printf("ARPING to %s", inet_ntoa(dst));
401 printf(" from %s via %s\n", inet_ntoa(src), device);
402 }
403
404 signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish);
405 signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);
406
407 catcher();
408
409 packet = xmalloc(4096);
410 while (1) {
411 sigset_t sset, osset;
412 struct sockaddr_ll from;
413 socklen_t alen = sizeof(from);
414 int cc;
415
416 cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen);
417 if (cc < 0) {
418 bb_perror_msg("recvfrom");
419 continue;
420 }
421 sigemptyset(&sset);
422 sigaddset(&sset, SIGALRM);
423 sigaddset(&sset, SIGINT);
424 sigprocmask(SIG_BLOCK, &sset, &osset);
425 recv_pack(packet, cc, &from);
426 sigprocmask(SIG_SETMASK, &osset, NULL);
427 }
428}
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