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 |
|
---|
19 | enum {
|
---|
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 |
|
---|
29 | struct 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 |
|
---|
73 | static 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 |
|
---|
108 | static void finish(void) NORETURN;
|
---|
109 | static 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 |
|
---|
126 | static 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 |
|
---|
149 | static 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 |
|
---|
254 | int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
---|
255 | int 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 | }
|
---|