source: MondoRescue/branches/3.2/mindi-busybox/networking/arping.c@ 3232

Last change on this file since 3232 was 3232, checked in by Bruno Cornec, 10 years ago
  • Update mindi-busybox to 1.21.1
File size: 11.2 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 Duplicated address detection mode"
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 Time to wait for ARP reply, seconds"
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
32/* We don't expect to see 1000+ seconds delay, unsigned is enough */
33#define MONOTONIC_US() ((unsigned)monotonic_us())
34
35enum {
36 DAD = 1,
37 UNSOLICITED = 2,
38 ADVERT = 4,
39 QUIET = 8,
40 QUIT_ON_REPLY = 16,
41 BCAST_ONLY = 32,
42 UNICASTING = 64
43};
44
45struct globals {
46 struct in_addr src;
47 struct in_addr dst;
48 struct sockaddr_ll me;
49 struct sockaddr_ll he;
50 int sock_fd;
51
52 int count; // = -1;
53 unsigned last;
54 unsigned timeout_us;
55 unsigned start;
56
57 unsigned sent;
58 unsigned brd_sent;
59 unsigned received;
60 unsigned brd_recv;
61 unsigned req_recv;
62} FIX_ALIASING;
63#define G (*(struct globals*)&bb_common_bufsiz1)
64#define src (G.src )
65#define dst (G.dst )
66#define me (G.me )
67#define he (G.he )
68#define sock_fd (G.sock_fd )
69#define count (G.count )
70#define last (G.last )
71#define timeout_us (G.timeout_us)
72#define start (G.start )
73#define sent (G.sent )
74#define brd_sent (G.brd_sent )
75#define received (G.received )
76#define brd_recv (G.brd_recv )
77#define req_recv (G.req_recv )
78#define INIT_G() do { \
79 count = -1; \
80} while (0)
81
82// If GNUisms are not available...
83//static void *mempcpy(void *_dst, const void *_src, int n)
84//{
85// memcpy(_dst, _src, n);
86// return (char*)_dst + n;
87//}
88
89static int send_pack(struct in_addr *src_addr,
90 struct in_addr *dst_addr, struct sockaddr_ll *ME,
91 struct sockaddr_ll *HE)
92{
93 int err;
94 unsigned char buf[256];
95 struct arphdr *ah = (struct arphdr *) buf;
96 unsigned char *p = (unsigned char *) (ah + 1);
97
98 ah->ar_hrd = htons(ARPHRD_ETHER);
99 ah->ar_pro = htons(ETH_P_IP);
100 ah->ar_hln = ME->sll_halen;
101 ah->ar_pln = 4;
102 ah->ar_op = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
103
104 p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
105 p = mempcpy(p, src_addr, 4);
106
107 if (option_mask32 & ADVERT)
108 p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
109 else
110 p = mempcpy(p, &HE->sll_addr, ah->ar_hln);
111
112 p = mempcpy(p, dst_addr, 4);
113
114 err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
115 if (err == p - buf) {
116 last = MONOTONIC_US();
117 sent++;
118 if (!(option_mask32 & UNICASTING))
119 brd_sent++;
120 }
121 return err;
122}
123
124static void finish(void) NORETURN;
125static void finish(void)
126{
127 if (!(option_mask32 & QUIET)) {
128 printf("Sent %u probe(s) (%u broadcast(s))\n"
129 "Received %u repl%s"
130 " (%u request(s), %u broadcast(s))\n",
131 sent, brd_sent,
132 received, (received == 1) ? "ies" : "y",
133 req_recv, brd_recv);
134 }
135 if (option_mask32 & DAD)
136 exit(!!received);
137 if (option_mask32 & UNSOLICITED)
138 exit(EXIT_SUCCESS);
139 exit(!received);
140}
141
142static void catcher(void)
143{
144 unsigned now;
145
146 now = MONOTONIC_US();
147 if (start == 0)
148 start = now;
149
150 if (count == 0 || (timeout_us && (now - start) > timeout_us))
151 finish();
152
153 /* count < 0 means "infinite count" */
154 if (count > 0)
155 count--;
156
157 if (last == 0 || (now - last) > 500000) {
158 send_pack(&src, &dst, &me, &he);
159 if (count == 0 && (option_mask32 & UNSOLICITED))
160 finish();
161 }
162 alarm(1);
163}
164
165static bool recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
166{
167 struct arphdr *ah = (struct arphdr *) buf;
168 unsigned char *p = (unsigned char *) (ah + 1);
169 struct in_addr src_ip, dst_ip;
170 /* moves below assume in_addr is 4 bytes big, ensure that */
171 struct BUG_in_addr_must_be_4 {
172 char BUG_in_addr_must_be_4[
173 sizeof(struct in_addr) == 4 ? 1 : -1
174 ];
175 char BUG_s_addr_must_be_4[
176 sizeof(src_ip.s_addr) == 4 ? 1 : -1
177 ];
178 };
179
180 /* Filter out wild packets */
181 if (FROM->sll_pkttype != PACKET_HOST
182 && FROM->sll_pkttype != PACKET_BROADCAST
183 && FROM->sll_pkttype != PACKET_MULTICAST)
184 return false;
185
186 /* Only these types are recognized */
187 if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
188 return false;
189
190 /* ARPHRD check and this darned FDDI hack here :-( */
191 if (ah->ar_hrd != htons(FROM->sll_hatype)
192 && (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
193 return false;
194
195 /* Protocol must be IP. */
196 if (ah->ar_pro != htons(ETH_P_IP)
197 || (ah->ar_pln != 4)
198 || (ah->ar_hln != me.sll_halen)
199 || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
200 return false;
201
202 move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
203 move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);
204
205 if (dst.s_addr != src_ip.s_addr)
206 return false;
207 if (!(option_mask32 & DAD)) {
208 if ((src.s_addr != dst_ip.s_addr)
209 || (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)))
210 return false;
211 } else {
212 /* DAD packet was:
213 src_ip = 0 (or some src)
214 src_hw = ME
215 dst_ip = tested address
216 dst_hw = <unspec>
217
218 We fail, if receive request/reply with:
219 src_ip = tested_address
220 src_hw != ME
221 if src_ip in request was not zero, check
222 also that it matches to dst_ip, otherwise
223 dst_ip/dst_hw do not matter.
224 */
225 if ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
226 || (src.s_addr && src.s_addr != dst_ip.s_addr))
227 return false;
228 }
229 if (!(option_mask32 & QUIET)) {
230 int s_printed = 0;
231
232 printf("%scast re%s from %s [%s]",
233 FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
234 ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
235 inet_ntoa(src_ip),
236 ether_ntoa((struct ether_addr *) p));
237 if (dst_ip.s_addr != src.s_addr) {
238 printf("for %s ", inet_ntoa(dst_ip));
239 s_printed = 1;
240 }
241 if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
242 if (!s_printed)
243 printf("for ");
244 printf("[%s]",
245 ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
246 }
247
248 if (last) {
249 unsigned diff = MONOTONIC_US() - last;
250 printf(" %u.%03ums\n", diff / 1000, diff % 1000);
251 } else {
252 printf(" UNSOLICITED?\n");
253 }
254 fflush_all();
255 }
256 received++;
257 if (FROM->sll_pkttype != PACKET_HOST)
258 brd_recv++;
259 if (ah->ar_op == htons(ARPOP_REQUEST))
260 req_recv++;
261 if (option_mask32 & QUIT_ON_REPLY)
262 finish();
263 if (!(option_mask32 & BCAST_ONLY)) {
264 memcpy(he.sll_addr, p, me.sll_halen);
265 option_mask32 |= UNICASTING;
266 }
267 return true;
268}
269
270int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
271int arping_main(int argc UNUSED_PARAM, char **argv)
272{
273 const char *device = "eth0";
274 char *source = NULL;
275 char *target;
276 unsigned char *packet;
277 char *err_str;
278
279 INIT_G();
280
281 sock_fd = xsocket(AF_PACKET, SOCK_DGRAM, 0);
282
283 // Drop suid root privileges
284 // Need to remove SUID_NEVER from applets.h for this to work
285 //xsetuid(getuid());
286
287 err_str = xasprintf("interface %s %%s", device);
288 {
289 unsigned opt;
290 char *str_timeout;
291
292 /* Dad also sets quit_on_reply.
293 * Advert also sets unsolicited.
294 */
295 opt_complementary = "=1:Df:AU:c+";
296 opt = getopt32(argv, "DUAqfbc:w:I:s:",
297 &count, &str_timeout, &device, &source);
298 if (opt & 0x80) /* -w: timeout */
299 timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000;
300 //if (opt & 0x200) /* -s: source */
301 option_mask32 &= 0x3f; /* set respective flags */
302 }
303
304 target = argv[optind];
305
306 xfunc_error_retval = 2;
307
308 {
309 struct ifreq ifr;
310
311 memset(&ifr, 0, sizeof(ifr));
312 strncpy_IFNAMSIZ(ifr.ifr_name, device);
313 /* We use ifr.ifr_name in error msg so that problem
314 * with truncated name will be visible */
315 ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");
316 me.sll_ifindex = ifr.ifr_ifindex;
317
318 xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr);
319
320 if (!(ifr.ifr_flags & IFF_UP)) {
321 bb_error_msg_and_die(err_str, "is down");
322 }
323 if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
324 bb_error_msg(err_str, "is not ARPable");
325 return (option_mask32 & DAD ? 0 : 2);
326 }
327 }
328
329 /* if (!inet_aton(target, &dst)) - not needed */ {
330 len_and_sockaddr *lsa;
331 lsa = xhost_and_af2sockaddr(target, 0, AF_INET);
332 dst = lsa->u.sin.sin_addr;
333 if (ENABLE_FEATURE_CLEAN_UP)
334 free(lsa);
335 }
336
337 if (source && !inet_aton(source, &src)) {
338 bb_error_msg_and_die("invalid source address %s", source);
339 }
340
341 if ((option_mask32 & (DAD|UNSOLICITED)) == UNSOLICITED && src.s_addr == 0)
342 src = dst;
343
344 if (!(option_mask32 & DAD) || src.s_addr) {
345 struct sockaddr_in saddr;
346 int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
347
348 setsockopt_bindtodevice(probe_fd, device);
349 memset(&saddr, 0, sizeof(saddr));
350 saddr.sin_family = AF_INET;
351 if (src.s_addr) {
352 /* Check that this is indeed our IP */
353 saddr.sin_addr = src;
354 xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
355 } else { /* !(option_mask32 & DAD) case */
356 /* Find IP address on this iface */
357 socklen_t alen = sizeof(saddr);
358
359 saddr.sin_port = htons(1025);
360 saddr.sin_addr = dst;
361
362 if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1)
363 bb_perror_msg("setsockopt(SO_DONTROUTE)");
364 xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
365 getsockname(probe_fd, (struct sockaddr *) &saddr, &alen);
366 //never happens:
367 //if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1)
368 // bb_perror_msg_and_die("getsockname");
369 if (saddr.sin_family != AF_INET)
370 bb_error_msg_and_die("no IP address configured");
371 src = saddr.sin_addr;
372 }
373 close(probe_fd);
374 }
375
376 me.sll_family = AF_PACKET;
377 //me.sll_ifindex = ifindex; - done before
378 me.sll_protocol = htons(ETH_P_ARP);
379 xbind(sock_fd, (struct sockaddr *) &me, sizeof(me));
380
381 {
382 socklen_t alen = sizeof(me);
383 getsockname(sock_fd, (struct sockaddr *) &me, &alen);
384 //never happens:
385 //if (getsockname(sock_fd, (struct sockaddr *) &me, &alen) == -1)
386 // bb_perror_msg_and_die("getsockname");
387 }
388 if (me.sll_halen == 0) {
389 bb_error_msg(err_str, "is not ARPable (no ll address)");
390 return (option_mask32 & DAD ? 0 : 2);
391 }
392 he = me;
393 memset(he.sll_addr, -1, he.sll_halen);
394
395 if (!(option_mask32 & QUIET)) {
396 /* inet_ntoa uses static storage, can't use in same printf */
397 printf("ARPING to %s", inet_ntoa(dst));
398 printf(" from %s via %s\n", inet_ntoa(src), device);
399 }
400
401 signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish);
402 signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);
403
404 catcher();
405
406 packet = xmalloc(4096);
407 while (1) {
408 sigset_t sset, osset;
409 struct sockaddr_ll from;
410 socklen_t alen = sizeof(from);
411 int cc;
412
413 cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen);
414 if (cc < 0) {
415 bb_perror_msg("recvfrom");
416 continue;
417 }
418 sigemptyset(&sset);
419 sigaddset(&sset, SIGALRM);
420 sigaddset(&sset, SIGINT);
421 sigprocmask(SIG_BLOCK, &sset, &osset);
422 recv_pack(packet, cc, &from);
423 sigprocmask(SIG_SETMASK, &osset, NULL);
424 }
425}
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