busybox/networking/arping.c

/* vi: set sw=4 ts=4: */
/*
 * arping.c - Ping hosts by ARP requests/replies
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 * Author:	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
 * Busybox port: Nick Fedchik <nick@fedchik.org.ua>
 */

#include <sys/ioctl.h>
#include <signal.h>

#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <netpacket/packet.h>

#include "busybox.h"

static struct in_addr src;
static struct in_addr dst;
static struct sockaddr_ll me;
static struct sockaddr_ll he;
static struct timeval last;

enum cfg_e {
	dad = 1,
	unsolicited = 2,
	advert = 4,
	quiet = 8,
	quit_on_reply = 16,
	broadcast_only = 32,
	unicasting = 64
};
static int cfg;

static int s;
static unsigned count = UINT_MAX;
static unsigned timeout;
static int sent;
static int brd_sent;
static int received;
static int brd_recv;
static int req_recv;

#define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \
			((tv1).tv_usec-(tv2).tv_usec)/1000 )

static int send_pack(int sock, struct in_addr *src_addr,
			struct in_addr *dst_addr, struct sockaddr_ll *ME,
			struct sockaddr_ll *HE)
{
	int err;
	struct timeval now;
	RESERVE_CONFIG_UBUFFER(buf, 256);
	struct arphdr *ah = (struct arphdr *) buf;
	unsigned char *p = (unsigned char *) (ah + 1);

	ah->ar_hrd = htons(ME->sll_hatype);
	ah->ar_hrd = htons(ARPHRD_ETHER);
	ah->ar_pro = htons(ETH_P_IP);
	ah->ar_hln = ME->sll_halen;
	ah->ar_pln = 4;
	ah->ar_op = cfg & advert ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);

	memcpy(p, &ME->sll_addr, ah->ar_hln);
	p += ME->sll_halen;

	memcpy(p, src_addr, 4);
	p += 4;

	if (cfg & advert)
		memcpy(p, &ME->sll_addr, ah->ar_hln);
	else
		memcpy(p, &HE->sll_addr, ah->ar_hln);
	p += ah->ar_hln;

	memcpy(p, dst_addr, 4);
	p += 4;

	gettimeofday(&now, NULL);
	err = sendto(sock, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
	if (err == p - buf) {
		last = now;
		sent++;
		if (!(cfg & unicasting))
			brd_sent++;
	}
	RELEASE_CONFIG_BUFFER(buf);
	return err;
}

static void finish(void)
{
	if (!(cfg & quiet)) {
		printf("Sent %d probe(s) (%d broadcast(s))\n"
			"Received %d repl%s"
			" (%d request(s), %d broadcast(s))\n",
			sent, brd_sent,
			received, (received == 1) ? "ies" : "y",
			req_recv, brd_recv);
	}
	if (cfg & dad)
		exit(!!received);
	if (cfg & unsolicited)
		exit(0);
	exit(!received);
}

static void catcher(void)
{
	struct timeval tv;
	static struct timeval start;

	gettimeofday(&tv, NULL);

	if (start.tv_sec == 0)
		start = tv;

	if (count-- == 0
	 || (timeout && MS_TDIFF(tv, start) > timeout * 1000 + 500))
		finish();

	if (last.tv_sec == 0 || MS_TDIFF(tv, last) > 500) {
		send_pack(s, &src, &dst, &me, &he);
		if (count == 0 && (cfg & unsolicited))
			finish();
	}
	alarm(1);
}

static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
{
	struct arphdr *ah = (struct arphdr *) buf;
	unsigned char *p = (unsigned char *) (ah + 1);
	struct in_addr src_ip, dst_ip;

	/* Filter out wild packets */
	if (FROM->sll_pkttype != PACKET_HOST
	 && FROM->sll_pkttype != PACKET_BROADCAST
	 && FROM->sll_pkttype != PACKET_MULTICAST)
		return 0;

	/* Only these types are recognised */
	if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
		return 0;

	/* ARPHRD check and this darned FDDI hack here :-( */
	if (ah->ar_hrd != htons(FROM->sll_hatype)
	 && (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
		return 0;

	/* Protocol must be IP. */
	if (ah->ar_pro != htons(ETH_P_IP))
		return 0;
	if (ah->ar_pln != 4)
		return 0;
	if (ah->ar_hln != me.sll_halen)
		return 0;
	if (len < sizeof(*ah) + 2 * (4 + ah->ar_hln))
		return 0;
	memcpy(&src_ip, p + ah->ar_hln, 4);
	memcpy(&dst_ip, p + ah->ar_hln + 4 + ah->ar_hln, 4);
	if (!(cfg & dad)) {
		if (src_ip.s_addr != dst.s_addr)
			return 0;
		if (src.s_addr != dst_ip.s_addr)
			return 0;
		if (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln))
			return 0;
	} else {
		/* DAD packet was:
		   src_ip = 0 (or some src)
		   src_hw = ME
		   dst_ip = tested address
		   dst_hw = <unspec>

		   We fail, if receive request/reply with:
		   src_ip = tested_address
		   src_hw != ME
		   if src_ip in request was not zero, check
		   also that it matches to dst_ip, otherwise
		   dst_ip/dst_hw do not matter.
		 */
		if (src_ip.s_addr != dst.s_addr)
			return 0;
		if (memcmp(p, &me.sll_addr, me.sll_halen) == 0)
			return 0;
		if (src.s_addr && src.s_addr != dst_ip.s_addr)
			return 0;
	}
	if (!(cfg & quiet)) {
		int s_printed = 0;
		struct timeval tv;

		gettimeofday(&tv, NULL);

		printf("%scast re%s from %s [%s]",
			FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
			ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
			inet_ntoa(src_ip),
			ether_ntoa((struct ether_addr *) p));
		if (dst_ip.s_addr != src.s_addr) {
			printf("for %s ", inet_ntoa(dst_ip));
			s_printed = 1;
		}
		if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
			if (!s_printed)
				printf("for ");
			printf("[%s]",
				ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
		}

		if (last.tv_sec) {
			long usecs = (tv.tv_sec - last.tv_sec) * 1000000 +
				tv.tv_usec - last.tv_usec;
			long msecs = (usecs + 500) / 1000;

			usecs -= msecs * 1000 - 500;
			printf(" %ld.%03ldms\n", msecs, usecs);
		} else {
			printf(" UNSOLICITED?\n");
		}
		fflush(stdout);
	}
	received++;
	if (FROM->sll_pkttype != PACKET_HOST)
		brd_recv++;
	if (ah->ar_op == htons(ARPOP_REQUEST))
		req_recv++;
	if (cfg & quit_on_reply)
		finish();
	if (!(cfg & broadcast_only)) {
		memcpy(he.sll_addr, p, me.sll_halen);
		cfg |= unicasting;
	}
	return 1;
}

int arping_main(int argc, char **argv)
{
	char *device = "eth0";
	int ifindex;
	char *source = NULL;
	char *target;

	s = xsocket(PF_PACKET, SOCK_DGRAM, 0);

	// Drop suid root privileges
	xsetuid(getuid());

	{
		unsigned opt;
		char *_count, *_timeout;

		/* Dad also sets quit_on_reply.
		 * Advert also sets unsolicited.
		 */
		opt_complementary = "Df:AU";
		opt = getopt32(argc, argv, "DUAqfbc:w:i:s:",
					&_count, &_timeout, &device, &source);
		cfg |= opt & 0x3f; /* set respective flags */
		if (opt & 0x40) /* -c: count */
			count = xatou(_count);
		if (opt & 0x80) /* -w: timeout */
			timeout = xatoul_range(_timeout, 0, INT_MAX/2000);
		//if (opt & 0x100) /* -i: interface */
		if (strlen(device) > IF_NAMESIZE) {
			bb_error_msg_and_die("interface name '%s' is too long",
							device);
		}
		//if (opt & 0x200) /* -s: source */
	}
	argc -= optind;
	argv += optind;

	if (argc != 1)
		bb_show_usage();

	target = *argv;

	xfunc_error_retval = 2;

	{
		struct ifreq ifr;

		memset(&ifr, 0, sizeof(ifr));
		strncpy(ifr.ifr_name, device, IFNAMSIZ - 1);
		if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
			bb_error_msg_and_die("interface %s not found", device);
		}
		ifindex = ifr.ifr_ifindex;

		if (ioctl(s, SIOCGIFFLAGS, (char *) &ifr)) {
			bb_error_msg_and_die("SIOCGIFFLAGS");
		}
		if (!(ifr.ifr_flags & IFF_UP)) {
			bb_error_msg_and_die("interface %s is down", device);
		}
		if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
			bb_error_msg("interface %s is not ARPable", device);
			return (cfg & dad ? 0 : 2);
		}
	}

	if (!inet_aton(target, &dst)) {
		struct hostent *hp;

		hp = gethostbyname2(target, AF_INET);
		if (!hp) {
			bb_error_msg_and_die("invalid or unknown target %s", target);
		}
		memcpy(&dst, hp->h_addr, 4);
	}

	if (source && !inet_aton(source, &src)) {
		bb_error_msg_and_die("invalid source address %s", source);
	}

	if (!(cfg & dad) && (cfg & unsolicited) && src.s_addr == 0)
		src = dst;

	if (!(cfg & dad) || src.s_addr) {
		struct sockaddr_in saddr;
		int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);

		if (device) {
			if (setsockopt(probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device) + 1) == -1)
				bb_error_msg("warning: interface %s is ignored", device);
		}
		memset(&saddr, 0, sizeof(saddr));
		saddr.sin_family = AF_INET;
		if (src.s_addr) {
			saddr.sin_addr = src;
			xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
		} else if (!(cfg & dad)) {
			static const int on = 1;
			socklen_t alen = sizeof(saddr);

			saddr.sin_port = htons(1025);
			saddr.sin_addr = dst;

			if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, (char *) &on, sizeof(on)) == -1)
				bb_perror_msg("warning: setsockopt(SO_DONTROUTE)");
			xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
			if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1) {
				bb_error_msg_and_die("getsockname");
			}
			src = saddr.sin_addr;
		}
		close(probe_fd);
	}

	me.sll_family = AF_PACKET;
	me.sll_ifindex = ifindex;
	me.sll_protocol = htons(ETH_P_ARP);
	xbind(s, (struct sockaddr *) &me, sizeof(me));

	{
		socklen_t alen = sizeof(me);

		if (getsockname(s, (struct sockaddr *) &me, &alen) == -1) {
			bb_error_msg_and_die("getsockname");
		}
	}
	if (me.sll_halen == 0) {
		bb_error_msg("interface \"%s\" is not ARPable (no ll address)", device);
		return (cfg & dad ? 0 : 2);
	}
	he = me;
	memset(he.sll_addr, -1, he.sll_halen);

	if (!(cfg & quiet)) {
		printf("ARPING to %s from %s via %s\n",
			inet_ntoa(dst), inet_ntoa(src),
			device ? device : "unknown");
	}

	if (!src.s_addr && !(cfg & dad)) {
		bb_error_msg_and_die("no src address in the non-DAD mode");
	}

	{
		struct sigaction sa;

		memset(&sa, 0, sizeof(sa));
		sa.sa_flags = SA_RESTART;

		sa.sa_handler = (void (*)(int)) finish;
		sigaction(SIGINT, &sa, NULL);

		sa.sa_handler = (void (*)(int)) catcher;
		sigaction(SIGALRM, &sa, NULL);
	}

	catcher();

	while (1) {
		sigset_t sset, osset;
		RESERVE_CONFIG_UBUFFER(packet, 4096);
		struct sockaddr_ll from;
		socklen_t alen = sizeof(from);
		int cc;

		cc = recvfrom(s, packet, 4096, 0, (struct sockaddr *) &from, &alen);
		if (cc < 0) {
			bb_perror_msg("recvfrom");
			continue;
		}
		sigemptyset(&sset);
		sigaddset(&sset, SIGALRM);
		sigaddset(&sset, SIGINT);
		sigprocmask(SIG_BLOCK, &sset, &osset);
		recv_pack(packet, cc, &from);
		sigprocmask(SIG_SETMASK, &osset, NULL);
		RELEASE_CONFIG_BUFFER(packet);
	}
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* arping.c - Ping hosts by ARP requests/replies
4	*
5	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
6	*
7	* Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
8	* Busybox port: Nick Fedchik <nick@fedchik.org.ua>
9	*/
10
11	#include <sys/ioctl.h>
12	#include <signal.h>
13
14	#include <arpa/inet.h>
15	#include <net/if.h>
16	#include <netinet/ether.h>
17	#include <netpacket/packet.h>
18
19	#include "busybox.h"
20
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;
26
27	enum cfg_e {
28	dad = 1,
29	unsolicited = 2,
30	advert = 4,
31	quiet = 8,
32	quit_on_reply = 16,
33	broadcast_only = 32,
34	unicasting = 64
35	};
36	static int cfg;
37
38	static int s;
39	static unsigned count = UINT_MAX;
40	static unsigned timeout;
41	static int sent;
42	static int brd_sent;
43	static int received;
44	static int brd_recv;
45	static int req_recv;
46
47	#define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \
48	((tv1).tv_usec-(tv2).tv_usec)/1000 )
49
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)
53	{
54	int err;
55	struct timeval now;
56	RESERVE_CONFIG_UBUFFER(buf, 256);
57	struct arphdr ah = (struct arphdr ) buf;
58	unsigned char p = (unsigned char ) (ah + 1);
59
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;
64	ah->ar_pln = 4;
65	ah->ar_op = cfg & advert ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
66
67	memcpy(p, &ME->sll_addr, ah->ar_hln);
68	p += ME->sll_halen;
69
70	memcpy(p, src_addr, 4);
71	p += 4;
72
73	if (cfg & advert)
74	memcpy(p, &ME->sll_addr, ah->ar_hln);
75	else
76	memcpy(p, &HE->sll_addr, ah->ar_hln);
77	p += ah->ar_hln;
78
79	memcpy(p, dst_addr, 4);
80	p += 4;
81
82	gettimeofday(&now, NULL);
83	err = sendto(sock, buf, p - buf, 0, (struct sockaddr ) HE, sizeof(HE));
84	if (err == p - buf) {
85	last = now;
86	sent++;
87	if (!(cfg & unicasting))
88	brd_sent++;
89	}
90	RELEASE_CONFIG_BUFFER(buf);
91	return err;
92	}
93
94	static void finish(void)
95	{
96	if (!(cfg & quiet)) {
97	printf("Sent %d probe(s) (%d broadcast(s))\n"
98	"Received %d repl%s"
99	" (%d request(s), %d broadcast(s))\n",
100	sent, brd_sent,
101	received, (received == 1) ? "ies" : "y",
102	req_recv, brd_recv);
103	}
104	if (cfg & dad)
105	exit(!!received);
106	if (cfg & unsolicited)
107	exit(0);
108	exit(!received);
109	}
110
111	static void catcher(void)
112	{
113	struct timeval tv;
114	static struct timeval start;
115
116	gettimeofday(&tv, NULL);
117
118	if (start.tv_sec == 0)
119	start = tv;
120
121	if (count-- == 0
122	\|\| (timeout && MS_TDIFF(tv, start) > timeout * 1000 + 500))
123	finish();
124
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))
128	finish();
129	}
130	alarm(1);
131	}
132
133	static int recv_pack(unsigned char buf, int len, struct sockaddr_ll FROM)
134	{
135	struct arphdr ah = (struct arphdr ) buf;
136	unsigned char p = (unsigned char ) (ah + 1);
137	struct in_addr src_ip, dst_ip;
138
139	/* Filter out wild packets */
140	if (FROM->sll_pkttype != PACKET_HOST
141	&& FROM->sll_pkttype != PACKET_BROADCAST
142	&& FROM->sll_pkttype != PACKET_MULTICAST)
143	return 0;
144
145	/* Only these types are recognised */
146	if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
147	return 0;
148
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)))
152	return 0;
153
154	/* Protocol must be IP. */
155	if (ah->ar_pro != htons(ETH_P_IP))
156	return 0;
157	if (ah->ar_pln != 4)
158	return 0;
159	if (ah->ar_hln != me.sll_halen)
160	return 0;
161	if (len < sizeof(ah) + 2 (4 + ah->ar_hln))
162	return 0;
163	memcpy(&src_ip, p + ah->ar_hln, 4);
164	memcpy(&dst_ip, p + ah->ar_hln + 4 + ah->ar_hln, 4);
165	if (!(cfg & dad)) {
166	if (src_ip.s_addr != dst.s_addr)
167	return 0;
168	if (src.s_addr != dst_ip.s_addr)
169	return 0;
170	if (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln))
171	return 0;
172	} else {
173	/* DAD packet was:
174	src_ip = 0 (or some src)
175	src_hw = ME
176	dst_ip = tested address
177	dst_hw = <unspec>
178
179	We fail, if receive request/reply with:
180	src_ip = tested_address
181	src_hw != ME
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.
185	*/
186	if (src_ip.s_addr != dst.s_addr)
187	return 0;
188	if (memcmp(p, &me.sll_addr, me.sll_halen) == 0)
189	return 0;
190	if (src.s_addr && src.s_addr != dst_ip.s_addr)
191	return 0;
192	}
193	if (!(cfg & quiet)) {
194	int s_printed = 0;
195	struct timeval tv;
196
197	gettimeofday(&tv, NULL);
198
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",
202	inet_ntoa(src_ip),
203	ether_ntoa((struct ether_addr *) p));
204	if (dst_ip.s_addr != src.s_addr) {
205	printf("for %s ", inet_ntoa(dst_ip));
206	s_printed = 1;
207	}
208	if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
209	if (!s_printed)
210	printf("for ");
211	printf("[%s]",
212	ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
213	}
214
215	if (last.tv_sec) {
216	long usecs = (tv.tv_sec - last.tv_sec) * 1000000 +
217	tv.tv_usec - last.tv_usec;
218	long msecs = (usecs + 500) / 1000;
219
220	usecs -= msecs * 1000 - 500;
221	printf(" %ld.%03ldms\n", msecs, usecs);
222	} else {
223	printf(" UNSOLICITED?\n");
224	}
225	fflush(stdout);
226	}
227	received++;
228	if (FROM->sll_pkttype != PACKET_HOST)
229	brd_recv++;
230	if (ah->ar_op == htons(ARPOP_REQUEST))
231	req_recv++;
232	if (cfg & quit_on_reply)
233	finish();
234	if (!(cfg & broadcast_only)) {
235	memcpy(he.sll_addr, p, me.sll_halen);
236	cfg \|= unicasting;
237	}
238	return 1;
239	}
240
241	int arping_main(int argc, char **argv)
242	{
243	char *device = "eth0";
244	int ifindex;
245	char *source = NULL;
246	char *target;
247
248	s = xsocket(PF_PACKET, SOCK_DGRAM, 0);
249
250	// Drop suid root privileges
251	xsetuid(getuid());
252
253	{
254	unsigned opt;
255	char _count, _timeout;
256
257	/* Dad also sets quit_on_reply.
258	* Advert also sets unsolicited.
259	*/
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",
271	device);
272	}
273	//if (opt & 0x200) /* -s: source */
274	}
275	argc -= optind;
276	argv += optind;
277
278	if (argc != 1)
279	bb_show_usage();
280
281	target = *argv;
282
283	xfunc_error_retval = 2;
284
285	{
286	struct ifreq ifr;
287
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);
292	}
293	ifindex = ifr.ifr_ifindex;
294
295	if (ioctl(s, SIOCGIFFLAGS, (char *) &ifr)) {
296	bb_error_msg_and_die("SIOCGIFFLAGS");
297	}
298	if (!(ifr.ifr_flags & IFF_UP)) {
299	bb_error_msg_and_die("interface %s is down", device);
300	}
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);
304	}
305	}
306
307	if (!inet_aton(target, &dst)) {
308	struct hostent *hp;
309
310	hp = gethostbyname2(target, AF_INET);
311	if (!hp) {
312	bb_error_msg_and_die("invalid or unknown target %s", target);
313	}
314	memcpy(&dst, hp->h_addr, 4);
315	}
316
317	if (source && !inet_aton(source, &src)) {
318	bb_error_msg_and_die("invalid source address %s", source);
319	}
320
321	if (!(cfg & dad) && (cfg & unsolicited) && src.s_addr == 0)
322	src = dst;
323
324	if (!(cfg & dad) \|\| src.s_addr) {
325	struct sockaddr_in saddr;
326	int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
327
328	if (device) {
329	if (setsockopt(probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device) + 1) == -1)
330	bb_error_msg("warning: interface %s is ignored", device);
331	}
332	memset(&saddr, 0, sizeof(saddr));
333	saddr.sin_family = AF_INET;
334	if (src.s_addr) {
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);
340
341	saddr.sin_port = htons(1025);
342	saddr.sin_addr = dst;
343
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");
349	}
350	src = saddr.sin_addr;
351	}
352	close(probe_fd);
353	}
354
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));
359
360	{
361	socklen_t alen = sizeof(me);
362
363	if (getsockname(s, (struct sockaddr *) &me, &alen) == -1) {
364	bb_error_msg_and_die("getsockname");
365	}
366	}
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);
370	}
371	he = me;
372	memset(he.sll_addr, -1, he.sll_halen);
373
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");
378	}
379
380	if (!src.s_addr && !(cfg & dad)) {
381	bb_error_msg_and_die("no src address in the non-DAD mode");
382	}
383
384	{
385	struct sigaction sa;
386
387	memset(&sa, 0, sizeof(sa));
388	sa.sa_flags = SA_RESTART;
389
390	sa.sa_handler = (void (*)(int)) finish;
391	sigaction(SIGINT, &sa, NULL);
392
393	sa.sa_handler = (void (*)(int)) catcher;
394	sigaction(SIGALRM, &sa, NULL);
395	}
396
397	catcher();
398
399	while (1) {
400	sigset_t sset, osset;
401	RESERVE_CONFIG_UBUFFER(packet, 4096);
402	struct sockaddr_ll from;
403	socklen_t alen = sizeof(from);
404	int cc;
405
406	cc = recvfrom(s, packet, 4096, 0, (struct sockaddr *) &from, &alen);
407	if (cc < 0) {
408	bb_perror_msg("recvfrom");
409	continue;
410	}
411	sigemptyset(&sset);
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);
418	}
419	}