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

#include "libbb.h"

/* We don't expect to see 1000+ seconds delay, unsigned is enough */
#define MONOTONIC_US() ((unsigned)monotonic_us())

enum {
	DAD = 1,
	UNSOLICITED = 2,
	ADVERT = 4,
	QUIET = 8,
	QUIT_ON_REPLY = 16,
	BCAST_ONLY = 32,
	UNICASTING = 64
};

struct globals {
	struct in_addr src;
	struct in_addr dst;
	struct sockaddr_ll me;
	struct sockaddr_ll he;
	int sock_fd;

	int count; // = -1;
	unsigned last;
	unsigned timeout_us;
	unsigned start;

	unsigned sent;
	unsigned brd_sent;
	unsigned received;
	unsigned brd_recv;
	unsigned req_recv;
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define src        (G.src       )
#define dst        (G.dst       )
#define me         (G.me        )
#define he         (G.he        )
#define sock_fd    (G.sock_fd   )
#define count      (G.count     )
#define last       (G.last      )
#define timeout_us (G.timeout_us)
#define start      (G.start     )
#define sent       (G.sent      )
#define brd_sent   (G.brd_sent  )
#define received   (G.received  )
#define brd_recv   (G.brd_recv  )
#define req_recv   (G.req_recv  )
#define INIT_G() do { \
	count = -1; \
} while (0)

// If GNUisms are not available...
//static void *mempcpy(void *_dst, const void *_src, int n)
//{
//	memcpy(_dst, _src, n);
//	return (char*)_dst + n;
//}

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

	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 = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);

	p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
	p = mempcpy(p, src_addr, 4);

	if (option_mask32 & ADVERT)
		p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
	else
		p = mempcpy(p, &HE->sll_addr, ah->ar_hln);

	p = mempcpy(p, dst_addr, 4);

	err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
	if (err == p - buf) {
		last = MONOTONIC_US();
		sent++;
		if (!(option_mask32 & UNICASTING))
			brd_sent++;
	}
	return err;
}

static void finish(void) NORETURN;
static void finish(void)
{
	if (!(option_mask32 & QUIET)) {
		printf("Sent %u probe(s) (%u broadcast(s))\n"
			"Received %u repl%s"
			" (%u request(s), %u broadcast(s))\n",
			sent, brd_sent,
			received, (received == 1) ? "ies" : "y",
			req_recv, brd_recv);
	}
	if (option_mask32 & DAD)
		exit(!!received);
	if (option_mask32 & UNSOLICITED)
		exit(EXIT_SUCCESS);
	exit(!received);
}

static void catcher(void)
{
	unsigned now;

	now = MONOTONIC_US();
	if (start == 0)
		start = now;

	if (count == 0 || (timeout_us && (now - start) > timeout_us))
		finish();

	/* count < 0 means "infinite count" */
	if (count > 0)
		count--;

	if (last == 0 || (now - last) > 500000) {
		send_pack(&src, &dst, &me, &he);
		if (count == 0 && (option_mask32 & UNSOLICITED))
			finish();
	}
	alarm(1);
}

static bool 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;
	/* moves below assume in_addr is 4 bytes big, ensure that */
	struct BUG_in_addr_must_be_4 {
		char BUG_in_addr_must_be_4[
			sizeof(struct in_addr) == 4 ? 1 : -1
		];
		char BUG_s_addr_must_be_4[
			sizeof(src_ip.s_addr) == 4 ? 1 : -1
		];
	};

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

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

	/* 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 false;

	/* Protocol must be IP. */
	if (ah->ar_pro != htons(ETH_P_IP)
	 || (ah->ar_pln != 4)
	 || (ah->ar_hln != me.sll_halen)
	 || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
		return false;

	move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
	move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);

	if (dst.s_addr != src_ip.s_addr)
		return false;
	if (!(option_mask32 & DAD)) {
		if ((src.s_addr != dst_ip.s_addr)
			|| (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)))
			return false;
	} 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 ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
		 || (src.s_addr && src.s_addr != dst_ip.s_addr))
			return false;
	}
	if (!(option_mask32 & QUIET)) {
		int s_printed = 0;

		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) {
			unsigned diff = MONOTONIC_US() - last;
			printf(" %u.%03ums\n", diff / 1000, diff % 1000);
		} else {
			printf(" UNSOLICITED?\n");
		}
		fflush_all();
	}
	received++;
	if (FROM->sll_pkttype != PACKET_HOST)
		brd_recv++;
	if (ah->ar_op == htons(ARPOP_REQUEST))
		req_recv++;
	if (option_mask32 & QUIT_ON_REPLY)
		finish();
	if (!(option_mask32 & BCAST_ONLY)) {
		memcpy(he.sll_addr, p, me.sll_halen);
		option_mask32 |= UNICASTING;
	}
	return true;
}

int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int arping_main(int argc UNUSED_PARAM, char **argv)
{
	const char *device = "eth0";
	char *source = NULL;
	char *target;
	unsigned char *packet;
	char *err_str;

	INIT_G();

	sock_fd = xsocket(AF_PACKET, SOCK_DGRAM, 0);

	// Drop suid root privileges
	// Need to remove SUID_NEVER from applets.h for this to work
	//xsetuid(getuid());

	err_str = xasprintf("interface %s %%s", device);
	{
		unsigned opt;
		char *str_timeout;

		/* Dad also sets quit_on_reply.
		 * Advert also sets unsolicited.
		 */
		opt_complementary = "=1:Df:AU:c+";
		opt = getopt32(argv, "DUAqfbc:w:I:s:",
				&count, &str_timeout, &device, &source);
		if (opt & 0x80) /* -w: timeout */
			timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000;
		//if (opt & 0x200) /* -s: source */
		option_mask32 &= 0x3f; /* set respective flags */
	}

	target = argv[optind];

	xfunc_error_retval = 2;

	{
		struct ifreq ifr;

		memset(&ifr, 0, sizeof(ifr));
		strncpy_IFNAMSIZ(ifr.ifr_name, device);
		/* We use ifr.ifr_name in error msg so that problem
		 * with truncated name will be visible */
		ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");
		me.sll_ifindex = ifr.ifr_ifindex;

		xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr);

		if (!(ifr.ifr_flags & IFF_UP)) {
			bb_error_msg_and_die(err_str, "is down");
		}
		if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
			bb_error_msg(err_str, "is not ARPable");
			return (option_mask32 & DAD ? 0 : 2);
		}
	}

	/* if (!inet_aton(target, &dst)) - not needed */ {
		len_and_sockaddr *lsa;
		lsa = xhost_and_af2sockaddr(target, 0, AF_INET);
		dst = lsa->u.sin.sin_addr;
		if (ENABLE_FEATURE_CLEAN_UP)
			free(lsa);
	}

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

	if ((option_mask32 & (DAD|UNSOLICITED)) == UNSOLICITED && src.s_addr == 0)
		src = dst;

	if (!(option_mask32 & DAD) || src.s_addr) {
		struct sockaddr_in saddr;
		int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);

		setsockopt_bindtodevice(probe_fd, device);
		memset(&saddr, 0, sizeof(saddr));
		saddr.sin_family = AF_INET;
		if (src.s_addr) {
			/* Check that this is indeed our IP */
			saddr.sin_addr = src;
			xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
		} else { /* !(option_mask32 & DAD) case */
			/* Find IP address on this iface */
			socklen_t alen = sizeof(saddr);

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

			if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1)
				bb_perror_msg("setsockopt(SO_DONTROUTE)");
			xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
			getsockname(probe_fd, (struct sockaddr *) &saddr, &alen);
			//never happens:
			//if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1)
			//	bb_perror_msg_and_die("getsockname");
			if (saddr.sin_family != AF_INET)
				bb_error_msg_and_die("no IP address configured");
			src = saddr.sin_addr;
		}
		close(probe_fd);
	}

	me.sll_family = AF_PACKET;
	//me.sll_ifindex = ifindex; - done before
	me.sll_protocol = htons(ETH_P_ARP);
	xbind(sock_fd, (struct sockaddr *) &me, sizeof(me));

	{
		socklen_t alen = sizeof(me);
		getsockname(sock_fd, (struct sockaddr *) &me, &alen);
		//never happens:
		//if (getsockname(sock_fd, (struct sockaddr *) &me, &alen) == -1)
		//	bb_perror_msg_and_die("getsockname");
	}
	if (me.sll_halen == 0) {
		bb_error_msg(err_str, "is not ARPable (no ll address)");
		return (option_mask32 & DAD ? 0 : 2);
	}
	he = me;
	memset(he.sll_addr, -1, he.sll_halen);

	if (!(option_mask32 & QUIET)) {
		/* inet_ntoa uses static storage, can't use in same printf */
		printf("ARPING to %s", inet_ntoa(dst));
		printf(" from %s via %s\n", inet_ntoa(src), device);
	}

	signal_SA_RESTART_empty_mask(SIGINT,  (void (*)(int))finish);
	signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);

	catcher();

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

		cc = recvfrom(sock_fd, 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);
	}
}
1	niro	532	/* 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 <arpa/inet.h>
12			#include <net/if.h>
13			#include <netinet/ether.h>
14			#include <netpacket/packet.h>
15
16	niro	816	#include "libbb.h"
17	niro	532
18	niro	816	/* We don't expect to see 1000+ seconds delay, unsigned is enough */
19			#define MONOTONIC_US() ((unsigned)monotonic_us())
20	niro	532
21	niro	816	enum {
22			DAD = 1,
23			UNSOLICITED = 2,
24			ADVERT = 4,
25			QUIET = 8,
26			QUIT_ON_REPLY = 16,
27			BCAST_ONLY = 32,
28			UNICASTING = 64
29	niro	532	};
30
31	niro	816	struct globals {
32			struct in_addr src;
33			struct in_addr dst;
34			struct sockaddr_ll me;
35			struct sockaddr_ll he;
36			int sock_fd;
37	niro	532
38	niro	816	int count; // = -1;
39			unsigned last;
40			unsigned timeout_us;
41			unsigned start;
42	niro	532
43	niro	816	unsigned sent;
44			unsigned brd_sent;
45			unsigned received;
46			unsigned brd_recv;
47			unsigned req_recv;
48	niro	1123	} FIX_ALIASING;
49	niro	816	#define G ((struct globals)&bb_common_bufsiz1)
50			#define src (G.src )
51			#define dst (G.dst )
52			#define me (G.me )
53			#define he (G.he )
54			#define sock_fd (G.sock_fd )
55			#define count (G.count )
56			#define last (G.last )
57			#define timeout_us (G.timeout_us)
58			#define start (G.start )
59			#define sent (G.sent )
60			#define brd_sent (G.brd_sent )
61			#define received (G.received )
62			#define brd_recv (G.brd_recv )
63			#define req_recv (G.req_recv )
64			#define INIT_G() do { \
65			count = -1; \
66			} while (0)
67
68			// If GNUisms are not available...
69			//static void mempcpy(void _dst, const void *_src, int n)
70			//{
71			// memcpy(_dst, _src, n);
72			// return (char*)_dst + n;
73			//}
74
75			static int send_pack(struct in_addr *src_addr,
76	niro	532	struct in_addr dst_addr, struct sockaddr_ll ME,
77			struct sockaddr_ll *HE)
78			{
79			int err;
80	niro	816	unsigned char buf[256];
81	niro	532	struct arphdr ah = (struct arphdr ) buf;
82			unsigned char p = (unsigned char ) (ah + 1);
83
84			ah->ar_hrd = htons(ARPHRD_ETHER);
85			ah->ar_pro = htons(ETH_P_IP);
86			ah->ar_hln = ME->sll_halen;
87			ah->ar_pln = 4;
88	niro	816	ah->ar_op = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
89	niro	532
90	niro	816	p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
91			p = mempcpy(p, src_addr, 4);
92	niro	532
93	niro	816	if (option_mask32 & ADVERT)
94			p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
95	niro	532	else
96	niro	816	p = mempcpy(p, &HE->sll_addr, ah->ar_hln);
97	niro	532
98	niro	816	p = mempcpy(p, dst_addr, 4);
99	niro	532
100	niro	816	err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr ) HE, sizeof(HE));
101	niro	532	if (err == p - buf) {
102	niro	816	last = MONOTONIC_US();
103	niro	532	sent++;
104	niro	816	if (!(option_mask32 & UNICASTING))
105	niro	532	brd_sent++;
106			}
107			return err;
108			}
109
110	niro	816	static void finish(void) NORETURN;
111	niro	532	static void finish(void)
112			{
113	niro	816	if (!(option_mask32 & QUIET)) {
114			printf("Sent %u probe(s) (%u broadcast(s))\n"
115			"Received %u repl%s"
116			" (%u request(s), %u broadcast(s))\n",
117	niro	532	sent, brd_sent,
118			received, (received == 1) ? "ies" : "y",
119			req_recv, brd_recv);
120			}
121	niro	816	if (option_mask32 & DAD)
122	niro	532	exit(!!received);
123	niro	816	if (option_mask32 & UNSOLICITED)
124			exit(EXIT_SUCCESS);
125	niro	532	exit(!received);
126			}
127
128			static void catcher(void)
129			{
130	niro	816	unsigned now;
131	niro	532
132	niro	816	now = MONOTONIC_US();
133			if (start == 0)
134			start = now;
135	niro	532
136	niro	816	if (count == 0 \|\| (timeout_us && (now - start) > timeout_us))
137	niro	532	finish();
138
139	niro	816	/* count < 0 means "infinite count" */
140			if (count > 0)
141			count--;
142
143			if (last == 0 \|\| (now - last) > 500000) {
144			send_pack(&src, &dst, &me, &he);
145			if (count == 0 && (option_mask32 & UNSOLICITED))
146	niro	532	finish();
147			}
148			alarm(1);
149			}
150
151	niro	816	static bool recv_pack(unsigned char buf, int len, struct sockaddr_ll FROM)
152	niro	532	{
153			struct arphdr ah = (struct arphdr ) buf;
154			unsigned char p = (unsigned char ) (ah + 1);
155			struct in_addr src_ip, dst_ip;
156	niro	984	/* moves below assume in_addr is 4 bytes big, ensure that */
157			struct BUG_in_addr_must_be_4 {
158			char BUG_in_addr_must_be_4[
159			sizeof(struct in_addr) == 4 ? 1 : -1
160			];
161			char BUG_s_addr_must_be_4[
162			sizeof(src_ip.s_addr) == 4 ? 1 : -1
163			];
164			};
165	niro	532
166			/* Filter out wild packets */
167			if (FROM->sll_pkttype != PACKET_HOST
168			&& FROM->sll_pkttype != PACKET_BROADCAST
169			&& FROM->sll_pkttype != PACKET_MULTICAST)
170	niro	816	return false;
171	niro	532
172	niro	984	/* Only these types are recognized */
173	niro	532	if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
174	niro	816	return false;
175	niro	532
176			/* ARPHRD check and this darned FDDI hack here :-( */
177			if (ah->ar_hrd != htons(FROM->sll_hatype)
178			&& (FROM->sll_hatype != ARPHRD_FDDI \|\| ah->ar_hrd != htons(ARPHRD_ETHER)))
179	niro	816	return false;
180	niro	532
181			/* Protocol must be IP. */
182	niro	816	if (ah->ar_pro != htons(ETH_P_IP)
183	niro	984	\|\| (ah->ar_pln != 4)
184			\|\| (ah->ar_hln != me.sll_halen)
185			\|\| (len < (int)(sizeof(ah) + 2 (4 + ah->ar_hln))))
186	niro	816	return false;
187
188	niro	984	move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
189			move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);
190	niro	816
191			if (dst.s_addr != src_ip.s_addr)
192			return false;
193			if (!(option_mask32 & DAD)) {
194			if ((src.s_addr != dst_ip.s_addr)
195			\|\| (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)))
196			return false;
197	niro	532	} else {
198			/* DAD packet was:
199			src_ip = 0 (or some src)
200			src_hw = ME
201			dst_ip = tested address
202			dst_hw = <unspec>
203
204			We fail, if receive request/reply with:
205			src_ip = tested_address
206			src_hw != ME
207			if src_ip in request was not zero, check
208			also that it matches to dst_ip, otherwise
209			dst_ip/dst_hw do not matter.
210			*/
211	niro	816	if ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
212	niro	984	\|\| (src.s_addr && src.s_addr != dst_ip.s_addr))
213	niro	816	return false;
214	niro	532	}
215	niro	816	if (!(option_mask32 & QUIET)) {
216	niro	532	int s_printed = 0;
217
218			printf("%scast re%s from %s [%s]",
219			FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
220			ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
221			inet_ntoa(src_ip),
222			ether_ntoa((struct ether_addr *) p));
223			if (dst_ip.s_addr != src.s_addr) {
224			printf("for %s ", inet_ntoa(dst_ip));
225			s_printed = 1;
226			}
227			if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
228			if (!s_printed)
229			printf("for ");
230			printf("[%s]",
231			ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
232			}
233
234	niro	816	if (last) {
235			unsigned diff = MONOTONIC_US() - last;
236			printf(" %u.%03ums\n", diff / 1000, diff % 1000);
237	niro	532	} else {
238			printf(" UNSOLICITED?\n");
239			}
240	niro	984	fflush_all();
241	niro	532	}
242			received++;
243			if (FROM->sll_pkttype != PACKET_HOST)
244			brd_recv++;
245			if (ah->ar_op == htons(ARPOP_REQUEST))
246			req_recv++;
247	niro	816	if (option_mask32 & QUIT_ON_REPLY)
248	niro	532	finish();
249	niro	816	if (!(option_mask32 & BCAST_ONLY)) {
250	niro	532	memcpy(he.sll_addr, p, me.sll_halen);
251	niro	816	option_mask32 \|= UNICASTING;
252	niro	532	}
253	niro	816	return true;
254	niro	532	}
255
256	niro	816	int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
257			int arping_main(int argc UNUSED_PARAM, char **argv)
258	niro	532	{
259	niro	816	const char *device = "eth0";
260	niro	532	char *source = NULL;
261			char *target;
262	niro	816	unsigned char *packet;
263			char *err_str;
264	niro	532
265	niro	816	INIT_G();
266	niro	532
267	niro	816	sock_fd = xsocket(AF_PACKET, SOCK_DGRAM, 0);
268
269	niro	532	// Drop suid root privileges
270	niro	816	// Need to remove SUID_NEVER from applets.h for this to work
271			//xsetuid(getuid());
272	niro	532
273	niro	816	err_str = xasprintf("interface %s %%s", device);
274	niro	532	{
275			unsigned opt;
276	niro	816	char *str_timeout;
277	niro	532
278			/* Dad also sets quit_on_reply.
279			* Advert also sets unsolicited.
280			*/
281	niro	816	opt_complementary = "=1:Df:AU:c+";
282			opt = getopt32(argv, "DUAqfbc:w:I:s:",
283			&count, &str_timeout, &device, &source);
284	niro	532	if (opt & 0x80) /* -w: timeout */
285	niro	816	timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000;
286	niro	532	//if (opt & 0x200) /* -s: source */
287	niro	816	option_mask32 &= 0x3f; /* set respective flags */
288	niro	532	}
289
290	niro	816	target = argv[optind];
291	niro	532
292			xfunc_error_retval = 2;
293
294			{
295			struct ifreq ifr;
296
297			memset(&ifr, 0, sizeof(ifr));
298	niro	984	strncpy_IFNAMSIZ(ifr.ifr_name, device);
299	niro	816	/* We use ifr.ifr_name in error msg so that problem
300			* with truncated name will be visible */
301			ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");
302			me.sll_ifindex = ifr.ifr_ifindex;
303	niro	532
304	niro	816	xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr);
305
306	niro	532	if (!(ifr.ifr_flags & IFF_UP)) {
307	niro	816	bb_error_msg_and_die(err_str, "is down");
308	niro	532	}
309			if (ifr.ifr_flags & (IFF_NOARP \| IFF_LOOPBACK)) {
310	niro	816	bb_error_msg(err_str, "is not ARPable");
311			return (option_mask32 & DAD ? 0 : 2);
312	niro	532	}
313			}
314
315	niro	816	/* if (!inet_aton(target, &dst)) - not needed */ {
316			len_and_sockaddr *lsa;
317			lsa = xhost_and_af2sockaddr(target, 0, AF_INET);
318	niro	984	dst = lsa->u.sin.sin_addr;
319	niro	816	if (ENABLE_FEATURE_CLEAN_UP)
320			free(lsa);
321	niro	532	}
322
323			if (source && !inet_aton(source, &src)) {
324			bb_error_msg_and_die("invalid source address %s", source);
325			}
326
327	niro	816	if ((option_mask32 & (DAD\|UNSOLICITED)) == UNSOLICITED && src.s_addr == 0)
328	niro	532	src = dst;
329
330	niro	816	if (!(option_mask32 & DAD) \|\| src.s_addr) {
331	niro	532	struct sockaddr_in saddr;
332			int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
333
334	niro	816	setsockopt_bindtodevice(probe_fd, device);
335	niro	532	memset(&saddr, 0, sizeof(saddr));
336			saddr.sin_family = AF_INET;
337			if (src.s_addr) {
338	niro	816	/* Check that this is indeed our IP */
339	niro	532	saddr.sin_addr = src;
340			xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
341	niro	816	} else { /* !(option_mask32 & DAD) case */
342			/* Find IP address on this iface */
343	niro	532	socklen_t alen = sizeof(saddr);
344
345			saddr.sin_port = htons(1025);
346			saddr.sin_addr = dst;
347
348	niro	816	if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1)
349			bb_perror_msg("setsockopt(SO_DONTROUTE)");
350	niro	532	xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
351	niro	984	getsockname(probe_fd, (struct sockaddr *) &saddr, &alen);
352			//never happens:
353			//if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1)
354			// bb_perror_msg_and_die("getsockname");
355	niro	816	if (saddr.sin_family != AF_INET)
356			bb_error_msg_and_die("no IP address configured");
357	niro	532	src = saddr.sin_addr;
358			}
359			close(probe_fd);
360			}
361
362			me.sll_family = AF_PACKET;
363	niro	816	//me.sll_ifindex = ifindex; - done before
364	niro	532	me.sll_protocol = htons(ETH_P_ARP);
365	niro	816	xbind(sock_fd, (struct sockaddr *) &me, sizeof(me));
366	niro	532
367			{
368			socklen_t alen = sizeof(me);
369	niro	984	getsockname(sock_fd, (struct sockaddr *) &me, &alen);
370			//never happens:
371			//if (getsockname(sock_fd, (struct sockaddr *) &me, &alen) == -1)
372			// bb_perror_msg_and_die("getsockname");
373	niro	532	}
374			if (me.sll_halen == 0) {
375	niro	816	bb_error_msg(err_str, "is not ARPable (no ll address)");
376			return (option_mask32 & DAD ? 0 : 2);
377	niro	532	}
378			he = me;
379			memset(he.sll_addr, -1, he.sll_halen);
380
381	niro	816	if (!(option_mask32 & QUIET)) {
382			/* inet_ntoa uses static storage, can't use in same printf */
383			printf("ARPING to %s", inet_ntoa(dst));
384			printf(" from %s via %s\n", inet_ntoa(src), device);
385	niro	532	}
386
387	niro	816	signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish);
388			signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);
389	niro	532
390			catcher();
391
392	niro	816	packet = xmalloc(4096);
393	niro	532	while (1) {
394			sigset_t sset, osset;
395			struct sockaddr_ll from;
396			socklen_t alen = sizeof(from);
397			int cc;
398
399	niro	816	cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen);
400	niro	532	if (cc < 0) {
401			bb_perror_msg("recvfrom");
402			continue;
403			}
404			sigemptyset(&sset);
405			sigaddset(&sset, SIGALRM);
406			sigaddset(&sset, SIGINT);
407			sigprocmask(SIG_BLOCK, &sset, &osset);
408			recv_pack(packet, cc, &from);
409			sigprocmask(SIG_SETMASK, &osset, NULL);
410			}
411			}