1 /* vi: set sw=4 ts=4: */
3 * arping.c - Ping hosts by ARP requests/replies
5 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
7 * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
8 * Busybox port: Nick Fedchik <nick@fedchik.org.ua>
11 #include <sys/ioctl.h>
14 #include <arpa/inet.h>
16 #include <netinet/ether.h>
17 #include <netpacket/packet.h>
21 static struct in_addr src;
22 static struct in_addr dst;
23 static struct sockaddr_ll me;
24 static struct sockaddr_ll he;
25 static struct timeval last;
39 static unsigned count = UINT_MAX;
40 static unsigned timeout;
47 #define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \
48 ((tv1).tv_usec-(tv2).tv_usec)/1000 )
50 static int send_pack(int sock, struct in_addr *src_addr,
51 struct in_addr *dst_addr, struct sockaddr_ll *ME,
52 struct sockaddr_ll *HE)
56 RESERVE_CONFIG_UBUFFER(buf, 256);
57 struct arphdr *ah = (struct arphdr *) buf;
58 unsigned char *p = (unsigned char *) (ah + 1);
60 ah->ar_hrd = htons(ME->sll_hatype);
61 ah->ar_hrd = htons(ARPHRD_ETHER);
62 ah->ar_pro = htons(ETH_P_IP);
63 ah->ar_hln = ME->sll_halen;
65 ah->ar_op = cfg & advert ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
67 memcpy(p, &ME->sll_addr, ah->ar_hln);
70 memcpy(p, src_addr, 4);
74 memcpy(p, &ME->sll_addr, ah->ar_hln);
76 memcpy(p, &HE->sll_addr, ah->ar_hln);
79 memcpy(p, dst_addr, 4);
82 gettimeofday(&now, NULL);
83 err = sendto(sock, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
87 if (!(cfg & unicasting))
90 RELEASE_CONFIG_BUFFER(buf);
94 static void finish(void)
97 printf("Sent %d probe(s) (%d broadcast(s))\n"
99 " (%d request(s), %d broadcast(s))\n",
101 received, (received == 1) ? "ies" : "y",
106 if (cfg & unsolicited)
111 static void catcher(void)
114 static struct timeval start;
116 gettimeofday(&tv, NULL);
118 if (start.tv_sec == 0)
122 || (timeout && MS_TDIFF(tv, start) > timeout * 1000 + 500))
125 if (last.tv_sec == 0 || MS_TDIFF(tv, last) > 500) {
126 send_pack(s, &src, &dst, &me, &he);
127 if (count == 0 && (cfg & unsolicited))
133 static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
135 struct arphdr *ah = (struct arphdr *) buf;
136 unsigned char *p = (unsigned char *) (ah + 1);
137 struct in_addr src_ip, dst_ip;
139 /* Filter out wild packets */
140 if (FROM->sll_pkttype != PACKET_HOST
141 && FROM->sll_pkttype != PACKET_BROADCAST
142 && FROM->sll_pkttype != PACKET_MULTICAST)
145 /* Only these types are recognised */
146 if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
149 /* ARPHRD check and this darned FDDI hack here :-( */
150 if (ah->ar_hrd != htons(FROM->sll_hatype)
151 && (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
154 /* Protocol must be IP. */
155 if (ah->ar_pro != htons(ETH_P_IP))
159 if (ah->ar_hln != me.sll_halen)
161 if (len < sizeof(*ah) + 2 * (4 + ah->ar_hln))
163 memcpy(&src_ip, p + ah->ar_hln, 4);
164 memcpy(&dst_ip, p + ah->ar_hln + 4 + ah->ar_hln, 4);
166 if (src_ip.s_addr != dst.s_addr)
168 if (src.s_addr != dst_ip.s_addr)
170 if (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln))
174 src_ip = 0 (or some src)
176 dst_ip = tested address
179 We fail, if receive request/reply with:
180 src_ip = tested_address
182 if src_ip in request was not zero, check
183 also that it matches to dst_ip, otherwise
184 dst_ip/dst_hw do not matter.
186 if (src_ip.s_addr != dst.s_addr)
188 if (memcmp(p, &me.sll_addr, me.sll_halen) == 0)
190 if (src.s_addr && src.s_addr != dst_ip.s_addr)
193 if (!(cfg & quiet)) {
197 gettimeofday(&tv, NULL);
199 printf("%scast re%s from %s [%s]",
200 FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
201 ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
203 ether_ntoa((struct ether_addr *) p));
204 if (dst_ip.s_addr != src.s_addr) {
205 printf("for %s ", inet_ntoa(dst_ip));
208 if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
212 ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
216 long usecs = (tv.tv_sec - last.tv_sec) * 1000000 +
217 tv.tv_usec - last.tv_usec;
218 long msecs = (usecs + 500) / 1000;
220 usecs -= msecs * 1000 - 500;
221 printf(" %ld.%03ldms\n", msecs, usecs);
223 printf(" UNSOLICITED?\n");
228 if (FROM->sll_pkttype != PACKET_HOST)
230 if (ah->ar_op == htons(ARPOP_REQUEST))
232 if (cfg & quit_on_reply)
234 if (!(cfg & broadcast_only)) {
235 memcpy(he.sll_addr, p, me.sll_halen);
241 int arping_main(int argc, char **argv)
243 char *device = "eth0";
248 s = xsocket(PF_PACKET, SOCK_DGRAM, 0);
250 // Drop suid root privileges
255 char *_count, *_timeout;
257 /* Dad also sets quit_on_reply.
258 * Advert also sets unsolicited.
260 opt_complementary = "Df:AU";
261 opt = getopt32(argc, argv, "DUAqfbc:w:i:s:",
262 &_count, &_timeout, &device, &source);
263 cfg |= opt & 0x3f; /* set respective flags */
264 if (opt & 0x40) /* -c: count */
265 count = xatou(_count);
266 if (opt & 0x80) /* -w: timeout */
267 timeout = xatoul_range(_timeout, 0, INT_MAX/2000);
268 //if (opt & 0x100) /* -i: interface */
269 if (strlen(device) > IF_NAMESIZE) {
270 bb_error_msg_and_die("interface name '%s' is too long",
273 //if (opt & 0x200) /* -s: source */
283 xfunc_error_retval = 2;
288 memset(&ifr, 0, sizeof(ifr));
289 strncpy(ifr.ifr_name, device, IFNAMSIZ - 1);
290 if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
291 bb_error_msg_and_die("interface %s not found", device);
293 ifindex = ifr.ifr_ifindex;
295 if (ioctl(s, SIOCGIFFLAGS, (char *) &ifr)) {
296 bb_error_msg_and_die("SIOCGIFFLAGS");
298 if (!(ifr.ifr_flags & IFF_UP)) {
299 bb_error_msg_and_die("interface %s is down", device);
301 if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
302 bb_error_msg("interface %s is not ARPable", device);
303 return (cfg & dad ? 0 : 2);
307 if (!inet_aton(target, &dst)) {
310 hp = gethostbyname2(target, AF_INET);
312 bb_error_msg_and_die("invalid or unknown target %s", target);
314 memcpy(&dst, hp->h_addr, 4);
317 if (source && !inet_aton(source, &src)) {
318 bb_error_msg_and_die("invalid source address %s", source);
321 if (!(cfg & dad) && (cfg & unsolicited) && src.s_addr == 0)
324 if (!(cfg & dad) || src.s_addr) {
325 struct sockaddr_in saddr;
326 int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
329 if (setsockopt(probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device) + 1) == -1)
330 bb_error_msg("warning: interface %s is ignored", device);
332 memset(&saddr, 0, sizeof(saddr));
333 saddr.sin_family = AF_INET;
335 saddr.sin_addr = src;
336 xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
337 } else if (!(cfg & dad)) {
338 static const int on = 1;
339 socklen_t alen = sizeof(saddr);
341 saddr.sin_port = htons(1025);
342 saddr.sin_addr = dst;
344 if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, (char *) &on, sizeof(on)) == -1)
345 bb_perror_msg("warning: setsockopt(SO_DONTROUTE)");
346 xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
347 if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1) {
348 bb_error_msg_and_die("getsockname");
350 src = saddr.sin_addr;
355 me.sll_family = AF_PACKET;
356 me.sll_ifindex = ifindex;
357 me.sll_protocol = htons(ETH_P_ARP);
358 xbind(s, (struct sockaddr *) &me, sizeof(me));
361 socklen_t alen = sizeof(me);
363 if (getsockname(s, (struct sockaddr *) &me, &alen) == -1) {
364 bb_error_msg_and_die("getsockname");
367 if (me.sll_halen == 0) {
368 bb_error_msg("interface \"%s\" is not ARPable (no ll address)", device);
369 return (cfg & dad ? 0 : 2);
372 memset(he.sll_addr, -1, he.sll_halen);
374 if (!(cfg & quiet)) {
375 printf("ARPING to %s from %s via %s\n",
376 inet_ntoa(dst), inet_ntoa(src),
377 device ? device : "unknown");
380 if (!src.s_addr && !(cfg & dad)) {
381 bb_error_msg_and_die("no src address in the non-DAD mode");
387 memset(&sa, 0, sizeof(sa));
388 sa.sa_flags = SA_RESTART;
390 sa.sa_handler = (void (*)(int)) finish;
391 sigaction(SIGINT, &sa, NULL);
393 sa.sa_handler = (void (*)(int)) catcher;
394 sigaction(SIGALRM, &sa, NULL);
400 sigset_t sset, osset;
401 RESERVE_CONFIG_UBUFFER(packet, 4096);
402 struct sockaddr_ll from;
403 socklen_t alen = sizeof(from);
406 cc = recvfrom(s, packet, 4096, 0, (struct sockaddr *) &from, &alen);
408 bb_perror_msg("recvfrom");
412 sigaddset(&sset, SIGALRM);
413 sigaddset(&sset, SIGINT);
414 sigprocmask(SIG_BLOCK, &sset, &osset);
415 recv_pack(packet, cc, &from);
416 sigprocmask(SIG_SETMASK, &osset, NULL);
417 RELEASE_CONFIG_BUFFER(packet);