1 /* vi: set sw=4 ts=4: */
3 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
5 * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 * Busybox port: Nick Fedchik <nick@fedchik.org.ua>
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"
14 //usage: "\n -f Quit on first ARP reply"
15 //usage: "\n -q Quiet"
16 //usage: "\n -b Keep broadcasting, don't go unicast"
17 //usage: "\n -D Duplicated address detection mode"
18 //usage: "\n -U Unsolicited ARP mode, update your neighbors"
19 //usage: "\n -A ARP answer mode, update your neighbors"
20 //usage: "\n -c N Stop after sending N ARP requests"
21 //usage: "\n -w TIMEOUT Time to wait for ARP reply, seconds"
22 //usage: "\n -I IFACE Interface to use (default eth0)"
23 //usage: "\n -s SRC_IP Sender IP address"
24 //usage: "\n DST_IP Target IP address"
26 #include <arpa/inet.h>
28 #include <netinet/ether.h>
29 #include <netpacket/packet.h>
33 /* We don't expect to see 1000+ seconds delay, unsigned is enough */
34 #define MONOTONIC_US() ((unsigned)monotonic_us())
49 struct sockaddr_ll me;
50 struct sockaddr_ll he;
64 #define G (*(struct globals*)&bb_common_bufsiz1)
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 { \
83 // If GNUisms are not available...
84 //static void *mempcpy(void *_dst, const void *_src, int n)
86 // memcpy(_dst, _src, n);
87 // return (char*)_dst + n;
90 static int send_pack(struct in_addr *src_addr,
91 struct in_addr *dst_addr, struct sockaddr_ll *ME,
92 struct sockaddr_ll *HE)
95 unsigned char buf[256];
96 struct arphdr *ah = (struct arphdr *) buf;
97 unsigned char *p = (unsigned char *) (ah + 1);
99 ah->ar_hrd = htons(ARPHRD_ETHER);
100 ah->ar_pro = htons(ETH_P_IP);
101 ah->ar_hln = ME->sll_halen;
103 ah->ar_op = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
105 p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
106 p = mempcpy(p, src_addr, 4);
108 if (option_mask32 & ADVERT)
109 p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
111 p = mempcpy(p, &HE->sll_addr, ah->ar_hln);
113 p = mempcpy(p, dst_addr, 4);
115 err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
116 if (err == p - buf) {
117 last = MONOTONIC_US();
119 if (!(option_mask32 & UNICASTING))
125 static void finish(void) NORETURN;
126 static void finish(void)
128 if (!(option_mask32 & QUIET)) {
129 printf("Sent %u probe(s) (%u broadcast(s))\n"
131 " (%u request(s), %u broadcast(s))\n",
133 received, (received == 1) ? "ies" : "y",
136 if (option_mask32 & DAD)
138 if (option_mask32 & UNSOLICITED)
143 static void catcher(void)
147 now = MONOTONIC_US();
151 if (count == 0 || (timeout_us && (now - start) > timeout_us))
154 /* count < 0 means "infinite count" */
158 if (last == 0 || (now - last) > 500000) {
159 send_pack(&src, &dst, &me, &he);
160 if (count == 0 && (option_mask32 & UNSOLICITED))
166 static bool recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
168 struct arphdr *ah = (struct arphdr *) buf;
169 unsigned char *p = (unsigned char *) (ah + 1);
170 struct in_addr src_ip, dst_ip;
171 /* moves below assume in_addr is 4 bytes big, ensure that */
172 struct BUG_in_addr_must_be_4 {
173 char BUG_in_addr_must_be_4[
174 sizeof(struct in_addr) == 4 ? 1 : -1
176 char BUG_s_addr_must_be_4[
177 sizeof(src_ip.s_addr) == 4 ? 1 : -1
181 /* Filter out wild packets */
182 if (FROM->sll_pkttype != PACKET_HOST
183 && FROM->sll_pkttype != PACKET_BROADCAST
184 && FROM->sll_pkttype != PACKET_MULTICAST)
187 /* Only these types are recognized */
188 if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
191 /* ARPHRD check and this darned FDDI hack here :-( */
192 if (ah->ar_hrd != htons(FROM->sll_hatype)
193 && (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
196 /* Protocol must be IP. */
197 if (ah->ar_pro != htons(ETH_P_IP)
199 || (ah->ar_hln != me.sll_halen)
200 || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
203 move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
204 move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);
206 if (dst.s_addr != src_ip.s_addr)
208 if (!(option_mask32 & DAD)) {
209 if ((src.s_addr != dst_ip.s_addr)
210 || (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)))
214 src_ip = 0 (or some src)
216 dst_ip = tested address
219 We fail, if receive request/reply with:
220 src_ip = tested_address
222 if src_ip in request was not zero, check
223 also that it matches to dst_ip, otherwise
224 dst_ip/dst_hw do not matter.
226 if ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
227 || (src.s_addr && src.s_addr != dst_ip.s_addr))
230 if (!(option_mask32 & QUIET)) {
233 printf("%scast re%s from %s [%s]",
234 FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
235 ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
237 ether_ntoa((struct ether_addr *) p));
238 if (dst_ip.s_addr != src.s_addr) {
239 printf("for %s ", inet_ntoa(dst_ip));
242 if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
246 ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
250 unsigned diff = MONOTONIC_US() - last;
251 printf(" %u.%03ums\n", diff / 1000, diff % 1000);
253 printf(" UNSOLICITED?\n");
258 if (FROM->sll_pkttype != PACKET_HOST)
260 if (ah->ar_op == htons(ARPOP_REQUEST))
262 if (option_mask32 & QUIT_ON_REPLY)
264 if (!(option_mask32 & BCAST_ONLY)) {
265 memcpy(he.sll_addr, p, me.sll_halen);
266 option_mask32 |= UNICASTING;
271 int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
272 int arping_main(int argc UNUSED_PARAM, char **argv)
274 const char *device = "eth0";
277 unsigned char *packet;
282 sock_fd = xsocket(AF_PACKET, SOCK_DGRAM, 0);
284 // Drop suid root privileges
285 // Need to remove SUID_NEVER from applets.h for this to work
288 err_str = xasprintf("interface %s %%s", device);
293 /* Dad also sets quit_on_reply.
294 * Advert also sets unsolicited.
296 opt_complementary = "=1:Df:AU:c+";
297 opt = getopt32(argv, "DUAqfbc:w:I:s:",
298 &count, &str_timeout, &device, &source);
299 if (opt & 0x80) /* -w: timeout */
300 timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000;
301 //if (opt & 0x200) /* -s: source */
302 option_mask32 &= 0x3f; /* set respective flags */
305 target = argv[optind];
307 xfunc_error_retval = 2;
312 memset(&ifr, 0, sizeof(ifr));
313 strncpy_IFNAMSIZ(ifr.ifr_name, device);
314 /* We use ifr.ifr_name in error msg so that problem
315 * with truncated name will be visible */
316 ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");
317 me.sll_ifindex = ifr.ifr_ifindex;
319 xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr);
321 if (!(ifr.ifr_flags & IFF_UP)) {
322 bb_error_msg_and_die(err_str, "is down");
324 if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
325 bb_error_msg(err_str, "is not ARPable");
326 return (option_mask32 & DAD ? 0 : 2);
330 /* if (!inet_aton(target, &dst)) - not needed */ {
331 len_and_sockaddr *lsa;
332 lsa = xhost_and_af2sockaddr(target, 0, AF_INET);
333 dst = lsa->u.sin.sin_addr;
334 if (ENABLE_FEATURE_CLEAN_UP)
338 if (source && !inet_aton(source, &src)) {
339 bb_error_msg_and_die("invalid source address %s", source);
342 if ((option_mask32 & (DAD|UNSOLICITED)) == UNSOLICITED && src.s_addr == 0)
345 if (!(option_mask32 & DAD) || src.s_addr) {
346 struct sockaddr_in saddr;
347 int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
349 setsockopt_bindtodevice(probe_fd, device);
350 memset(&saddr, 0, sizeof(saddr));
351 saddr.sin_family = AF_INET;
353 /* Check that this is indeed our IP */
354 saddr.sin_addr = src;
355 xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
356 } else { /* !(option_mask32 & DAD) case */
357 /* Find IP address on this iface */
358 socklen_t alen = sizeof(saddr);
360 saddr.sin_port = htons(1025);
361 saddr.sin_addr = dst;
363 if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1)
364 bb_perror_msg("setsockopt(SO_DONTROUTE)");
365 xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
366 getsockname(probe_fd, (struct sockaddr *) &saddr, &alen);
368 //if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1)
369 // bb_perror_msg_and_die("getsockname");
370 if (saddr.sin_family != AF_INET)
371 bb_error_msg_and_die("no IP address configured");
372 src = saddr.sin_addr;
377 me.sll_family = AF_PACKET;
378 //me.sll_ifindex = ifindex; - done before
379 me.sll_protocol = htons(ETH_P_ARP);
380 xbind(sock_fd, (struct sockaddr *) &me, sizeof(me));
383 socklen_t alen = sizeof(me);
384 getsockname(sock_fd, (struct sockaddr *) &me, &alen);
386 //if (getsockname(sock_fd, (struct sockaddr *) &me, &alen) == -1)
387 // bb_perror_msg_and_die("getsockname");
389 if (me.sll_halen == 0) {
390 bb_error_msg(err_str, "is not ARPable (no ll address)");
391 return (option_mask32 & DAD ? 0 : 2);
394 memset(he.sll_addr, -1, he.sll_halen);
396 if (!(option_mask32 & QUIET)) {
397 /* inet_ntoa uses static storage, can't use in same printf */
398 printf("ARPING to %s", inet_ntoa(dst));
399 printf(" from %s via %s\n", inet_ntoa(src), device);
402 signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish);
403 signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);
407 packet = xmalloc(4096);
409 sigset_t sset, osset;
410 struct sockaddr_ll from;
411 socklen_t alen = sizeof(from);
414 cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen);
416 bb_perror_msg("recvfrom");
420 sigaddset(&sset, SIGALRM);
421 sigaddset(&sset, SIGINT);
422 sigprocmask(SIG_BLOCK, &sset, &osset);
423 recv_pack(packet, cc, &from);
424 sigprocmask(SIG_SETMASK, &osset, NULL);