blob: a4421edcba01570a952bdfdd54590276266c2c49
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 | |
35 | enum { |
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 | |
45 | struct 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 | |
89 | static 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 | |
124 | static void finish(void) NORETURN; |
125 | static 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 | |
142 | static 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 | |
165 | static 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 | |
270 | int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
271 | int 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 | } |
426 |