source: MondoRescue/branches/2.2.9/mindi-busybox/networking/arping.c@ 2725

Last change on this file since 2725 was 2725, checked in by Bruno Cornec, 13 years ago
  • Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3
File size: 10.5 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#include <arpa/inet.h>
10#include <net/if.h>
11#include <netinet/ether.h>
12#include <netpacket/packet.h>
13
14#include "libbb.h"
15
16/* We don't expect to see 1000+ seconds delay, unsigned is enough */
17#define MONOTONIC_US() ((unsigned)monotonic_us())
18
19enum {
20 DAD = 1,
21 UNSOLICITED = 2,
22 ADVERT = 4,
23 QUIET = 8,
24 QUIT_ON_REPLY = 16,
25 BCAST_ONLY = 32,
26 UNICASTING = 64
27};
28
29struct globals {
30 struct in_addr src;
31 struct in_addr dst;
32 struct sockaddr_ll me;
33 struct sockaddr_ll he;
34 int sock_fd;
35
36 int count; // = -1;
37 unsigned last;
38 unsigned timeout_us;
39 unsigned start;
40
41 unsigned sent;
42 unsigned brd_sent;
43 unsigned received;
44 unsigned brd_recv;
45 unsigned req_recv;
46} FIX_ALIASING;
47#define G (*(struct globals*)&bb_common_bufsiz1)
48#define src (G.src )
49#define dst (G.dst )
50#define me (G.me )
51#define he (G.he )
52#define sock_fd (G.sock_fd )
53#define count (G.count )
54#define last (G.last )
55#define timeout_us (G.timeout_us)
56#define start (G.start )
57#define sent (G.sent )
58#define brd_sent (G.brd_sent )
59#define received (G.received )
60#define brd_recv (G.brd_recv )
61#define req_recv (G.req_recv )
62#define INIT_G() do { \
63 count = -1; \
64} while (0)
65
66// If GNUisms are not available...
67//static void *mempcpy(void *_dst, const void *_src, int n)
68//{
69// memcpy(_dst, _src, n);
70// return (char*)_dst + n;
71//}
72
73static int send_pack(struct in_addr *src_addr,
74 struct in_addr *dst_addr, struct sockaddr_ll *ME,
75 struct sockaddr_ll *HE)
76{
77 int err;
78 unsigned char buf[256];
79 struct arphdr *ah = (struct arphdr *) buf;
80 unsigned char *p = (unsigned char *) (ah + 1);
81
82 ah->ar_hrd = htons(ARPHRD_ETHER);
83 ah->ar_pro = htons(ETH_P_IP);
84 ah->ar_hln = ME->sll_halen;
85 ah->ar_pln = 4;
86 ah->ar_op = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
87
88 p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
89 p = mempcpy(p, src_addr, 4);
90
91 if (option_mask32 & ADVERT)
92 p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
93 else
94 p = mempcpy(p, &HE->sll_addr, ah->ar_hln);
95
96 p = mempcpy(p, dst_addr, 4);
97
98 err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
99 if (err == p - buf) {
100 last = MONOTONIC_US();
101 sent++;
102 if (!(option_mask32 & UNICASTING))
103 brd_sent++;
104 }
105 return err;
106}
107
108static void finish(void) NORETURN;
109static void finish(void)
110{
111 if (!(option_mask32 & QUIET)) {
112 printf("Sent %u probe(s) (%u broadcast(s))\n"
113 "Received %u repl%s"
114 " (%u request(s), %u broadcast(s))\n",
115 sent, brd_sent,
116 received, (received == 1) ? "ies" : "y",
117 req_recv, brd_recv);
118 }
119 if (option_mask32 & DAD)
120 exit(!!received);
121 if (option_mask32 & UNSOLICITED)
122 exit(EXIT_SUCCESS);
123 exit(!received);
124}
125
126static void catcher(void)
127{
128 unsigned now;
129
130 now = MONOTONIC_US();
131 if (start == 0)
132 start = now;
133
134 if (count == 0 || (timeout_us && (now - start) > timeout_us))
135 finish();
136
137 /* count < 0 means "infinite count" */
138 if (count > 0)
139 count--;
140
141 if (last == 0 || (now - last) > 500000) {
142 send_pack(&src, &dst, &me, &he);
143 if (count == 0 && (option_mask32 & UNSOLICITED))
144 finish();
145 }
146 alarm(1);
147}
148
149static bool recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
150{
151 struct arphdr *ah = (struct arphdr *) buf;
152 unsigned char *p = (unsigned char *) (ah + 1);
153 struct in_addr src_ip, dst_ip;
154 /* moves below assume in_addr is 4 bytes big, ensure that */
155 struct BUG_in_addr_must_be_4 {
156 char BUG_in_addr_must_be_4[
157 sizeof(struct in_addr) == 4 ? 1 : -1
158 ];
159 char BUG_s_addr_must_be_4[
160 sizeof(src_ip.s_addr) == 4 ? 1 : -1
161 ];
162 };
163
164 /* Filter out wild packets */
165 if (FROM->sll_pkttype != PACKET_HOST
166 && FROM->sll_pkttype != PACKET_BROADCAST
167 && FROM->sll_pkttype != PACKET_MULTICAST)
168 return false;
169
170 /* Only these types are recognized */
171 if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
172 return false;
173
174 /* ARPHRD check and this darned FDDI hack here :-( */
175 if (ah->ar_hrd != htons(FROM->sll_hatype)
176 && (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
177 return false;
178
179 /* Protocol must be IP. */
180 if (ah->ar_pro != htons(ETH_P_IP)
181 || (ah->ar_pln != 4)
182 || (ah->ar_hln != me.sll_halen)
183 || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
184 return false;
185
186 move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
187 move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);
188
189 if (dst.s_addr != src_ip.s_addr)
190 return false;
191 if (!(option_mask32 & DAD)) {
192 if ((src.s_addr != dst_ip.s_addr)
193 || (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)))
194 return false;
195 } else {
196 /* DAD packet was:
197 src_ip = 0 (or some src)
198 src_hw = ME
199 dst_ip = tested address
200 dst_hw = <unspec>
201
202 We fail, if receive request/reply with:
203 src_ip = tested_address
204 src_hw != ME
205 if src_ip in request was not zero, check
206 also that it matches to dst_ip, otherwise
207 dst_ip/dst_hw do not matter.
208 */
209 if ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
210 || (src.s_addr && src.s_addr != dst_ip.s_addr))
211 return false;
212 }
213 if (!(option_mask32 & QUIET)) {
214 int s_printed = 0;
215
216 printf("%scast re%s from %s [%s]",
217 FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
218 ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
219 inet_ntoa(src_ip),
220 ether_ntoa((struct ether_addr *) p));
221 if (dst_ip.s_addr != src.s_addr) {
222 printf("for %s ", inet_ntoa(dst_ip));
223 s_printed = 1;
224 }
225 if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
226 if (!s_printed)
227 printf("for ");
228 printf("[%s]",
229 ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
230 }
231
232 if (last) {
233 unsigned diff = MONOTONIC_US() - last;
234 printf(" %u.%03ums\n", diff / 1000, diff % 1000);
235 } else {
236 printf(" UNSOLICITED?\n");
237 }
238 fflush_all();
239 }
240 received++;
241 if (FROM->sll_pkttype != PACKET_HOST)
242 brd_recv++;
243 if (ah->ar_op == htons(ARPOP_REQUEST))
244 req_recv++;
245 if (option_mask32 & QUIT_ON_REPLY)
246 finish();
247 if (!(option_mask32 & BCAST_ONLY)) {
248 memcpy(he.sll_addr, p, me.sll_halen);
249 option_mask32 |= UNICASTING;
250 }
251 return true;
252}
253
254int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
255int arping_main(int argc UNUSED_PARAM, char **argv)
256{
257 const char *device = "eth0";
258 char *source = NULL;
259 char *target;
260 unsigned char *packet;
261 char *err_str;
262
263 INIT_G();
264
265 sock_fd = xsocket(AF_PACKET, SOCK_DGRAM, 0);
266
267 // Drop suid root privileges
268 // Need to remove SUID_NEVER from applets.h for this to work
269 //xsetuid(getuid());
270
271 err_str = xasprintf("interface %s %%s", device);
272 {
273 unsigned opt;
274 char *str_timeout;
275
276 /* Dad also sets quit_on_reply.
277 * Advert also sets unsolicited.
278 */
279 opt_complementary = "=1:Df:AU:c+";
280 opt = getopt32(argv, "DUAqfbc:w:I:s:",
281 &count, &str_timeout, &device, &source);
282 if (opt & 0x80) /* -w: timeout */
283 timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000;
284 //if (opt & 0x200) /* -s: source */
285 option_mask32 &= 0x3f; /* set respective flags */
286 }
287
288 target = argv[optind];
289
290 xfunc_error_retval = 2;
291
292 {
293 struct ifreq ifr;
294
295 memset(&ifr, 0, sizeof(ifr));
296 strncpy_IFNAMSIZ(ifr.ifr_name, device);
297 /* We use ifr.ifr_name in error msg so that problem
298 * with truncated name will be visible */
299 ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");
300 me.sll_ifindex = ifr.ifr_ifindex;
301
302 xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr);
303
304 if (!(ifr.ifr_flags & IFF_UP)) {
305 bb_error_msg_and_die(err_str, "is down");
306 }
307 if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
308 bb_error_msg(err_str, "is not ARPable");
309 return (option_mask32 & DAD ? 0 : 2);
310 }
311 }
312
313 /* if (!inet_aton(target, &dst)) - not needed */ {
314 len_and_sockaddr *lsa;
315 lsa = xhost_and_af2sockaddr(target, 0, AF_INET);
316 dst = lsa->u.sin.sin_addr;
317 if (ENABLE_FEATURE_CLEAN_UP)
318 free(lsa);
319 }
320
321 if (source && !inet_aton(source, &src)) {
322 bb_error_msg_and_die("invalid source address %s", source);
323 }
324
325 if ((option_mask32 & (DAD|UNSOLICITED)) == UNSOLICITED && src.s_addr == 0)
326 src = dst;
327
328 if (!(option_mask32 & DAD) || src.s_addr) {
329 struct sockaddr_in saddr;
330 int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
331
332 setsockopt_bindtodevice(probe_fd, device);
333 memset(&saddr, 0, sizeof(saddr));
334 saddr.sin_family = AF_INET;
335 if (src.s_addr) {
336 /* Check that this is indeed our IP */
337 saddr.sin_addr = src;
338 xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
339 } else { /* !(option_mask32 & DAD) case */
340 /* Find IP address on this iface */
341 socklen_t alen = sizeof(saddr);
342
343 saddr.sin_port = htons(1025);
344 saddr.sin_addr = dst;
345
346 if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1)
347 bb_perror_msg("setsockopt(SO_DONTROUTE)");
348 xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
349 getsockname(probe_fd, (struct sockaddr *) &saddr, &alen);
350 //never happens:
351 //if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1)
352 // bb_perror_msg_and_die("getsockname");
353 if (saddr.sin_family != AF_INET)
354 bb_error_msg_and_die("no IP address configured");
355 src = saddr.sin_addr;
356 }
357 close(probe_fd);
358 }
359
360 me.sll_family = AF_PACKET;
361 //me.sll_ifindex = ifindex; - done before
362 me.sll_protocol = htons(ETH_P_ARP);
363 xbind(sock_fd, (struct sockaddr *) &me, sizeof(me));
364
365 {
366 socklen_t alen = sizeof(me);
367 getsockname(sock_fd, (struct sockaddr *) &me, &alen);
368 //never happens:
369 //if (getsockname(sock_fd, (struct sockaddr *) &me, &alen) == -1)
370 // bb_perror_msg_and_die("getsockname");
371 }
372 if (me.sll_halen == 0) {
373 bb_error_msg(err_str, "is not ARPable (no ll address)");
374 return (option_mask32 & DAD ? 0 : 2);
375 }
376 he = me;
377 memset(he.sll_addr, -1, he.sll_halen);
378
379 if (!(option_mask32 & QUIET)) {
380 /* inet_ntoa uses static storage, can't use in same printf */
381 printf("ARPING to %s", inet_ntoa(dst));
382 printf(" from %s via %s\n", inet_ntoa(src), device);
383 }
384
385 signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish);
386 signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);
387
388 catcher();
389
390 packet = xmalloc(4096);
391 while (1) {
392 sigset_t sset, osset;
393 struct sockaddr_ll from;
394 socklen_t alen = sizeof(from);
395 int cc;
396
397 cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen);
398 if (cc < 0) {
399 bb_perror_msg("recvfrom");
400 continue;
401 }
402 sigemptyset(&sset);
403 sigaddset(&sset, SIGALRM);
404 sigaddset(&sset, SIGINT);
405 sigprocmask(SIG_BLOCK, &sset, &osset);
406 recv_pack(packet, cc, &from);
407 sigprocmask(SIG_SETMASK, &osset, NULL);
408 }
409}
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