[people/ms/u-boot.git] / net / link_local.c

/*
 * RFC3927 ZeroConf IPv4 Link-Local addressing
 * (see <http://www.zeroconf.org/>)
 *
 * Copied from BusyBox - networking/zcip.c
 *
 * Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com)
 * Copyright (C) 2004 by David Brownell
 * Copyright (C) 2010 by Joe Hershberger
 *
 * Licensed under the GPL v2 or later
 */

#include <common.h>
#include <net.h>
#include "arp.h"
#include "net_rand.h"

/* We don't need more than 32 bits of the counter */
#define MONOTONIC_MS() ((unsigned)get_timer(0) * (1000 / CONFIG_SYS_HZ))

enum {
/* 169.254.0.0 */
	LINKLOCAL_ADDR = 0xa9fe0000,

	IN_CLASSB_NET = 0xffff0000,
	IN_CLASSB_HOST = 0x0000ffff,

/* protocol timeout parameters, specified in seconds */
	PROBE_WAIT = 1,
	PROBE_MIN = 1,
	PROBE_MAX = 2,
	PROBE_NUM = 3,
	MAX_CONFLICTS = 10,
	RATE_LIMIT_INTERVAL = 60,
	ANNOUNCE_WAIT = 2,
	ANNOUNCE_NUM = 2,
	ANNOUNCE_INTERVAL = 2,
	DEFEND_INTERVAL = 10
};

/* States during the configuration process. */
static enum ll_state_t {
	PROBE = 0,
	RATE_LIMIT_PROBE,
	ANNOUNCE,
	MONITOR,
	DEFEND,
	DISABLED
} state = DISABLED;

static struct in_addr ip;
static int timeout_ms = -1;
static unsigned deadline_ms;
static unsigned conflicts;
static unsigned nprobes;
static unsigned nclaims;
static int ready;
static unsigned int seed;

static void link_local_timeout(void);

/**
 * Pick a random link local IP address on 169.254/16, except that
 * the first and last 256 addresses are reserved.
 */
static struct in_addr pick(void)
{
	unsigned tmp;
	struct in_addr ip;

	do {
		tmp = rand_r(&seed) & IN_CLASSB_HOST;
	} while (tmp > (IN_CLASSB_HOST - 0x0200));
	ip.s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
	return ip;
}

/**
 * Return milliseconds of random delay, up to "secs" seconds.
 */
static inline unsigned random_delay_ms(unsigned secs)
{
	return rand_r(&seed) % (secs * 1000);
}

static void configure_wait(void)
{
	if (timeout_ms == -1)
		return;

	/* poll, being ready to adjust current timeout */
	if (!timeout_ms)
		timeout_ms = random_delay_ms(PROBE_WAIT);

	/* set deadline_ms to the point in time when we timeout */
	deadline_ms = MONOTONIC_MS() + timeout_ms;

	debug_cond(DEBUG_DEV_PKT, "...wait %d %s nprobes=%u, nclaims=%u\n",
		   timeout_ms, eth_get_name(), nprobes, nclaims);

	net_set_timeout_handler(timeout_ms, link_local_timeout);
}

void link_local_start(void)
{
	ip = getenv_ip("llipaddr");
	if (ip.s_addr != 0 &&
	    (ntohl(ip.s_addr) & IN_CLASSB_NET) != LINKLOCAL_ADDR) {
		puts("invalid link address");
		net_set_state(NETLOOP_FAIL);
		return;
	}
	net_netmask.s_addr = htonl(IN_CLASSB_NET);

	seed = seed_mac();
	if (ip.s_addr == 0)
		ip = pick();

	state = PROBE;
	timeout_ms = 0;
	conflicts = 0;
	nprobes = 0;
	nclaims = 0;
	ready = 0;

	configure_wait();
}

static void link_local_timeout(void)
{
	switch (state) {
	case PROBE:
		/* timeouts in the PROBE state mean no conflicting ARP packets
		   have been received, so we can progress through the states */
		if (nprobes < PROBE_NUM) {
			struct in_addr zero_ip = {.s_addr = 0};

			nprobes++;
			debug_cond(DEBUG_LL_STATE, "probe/%u %s@%pI4\n",
				   nprobes, eth_get_name(), &ip);
			arp_raw_request(zero_ip, net_null_ethaddr, ip);
			timeout_ms = PROBE_MIN * 1000;
			timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
		} else {
			/* Switch to announce state */
			state = ANNOUNCE;
			nclaims = 0;
			debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
				   nclaims, eth_get_name(), &ip);
			arp_raw_request(ip, net_ethaddr, ip);
			timeout_ms = ANNOUNCE_INTERVAL * 1000;
		}
		break;
	case RATE_LIMIT_PROBE:
		/* timeouts in the RATE_LIMIT_PROBE state mean no conflicting
		   ARP packets have been received, so we can move immediately
		   to the announce state */
		state = ANNOUNCE;
		nclaims = 0;
		debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
			   nclaims, eth_get_name(), &ip);
		arp_raw_request(ip, net_ethaddr, ip);
		timeout_ms = ANNOUNCE_INTERVAL * 1000;
		break;
	case ANNOUNCE:
		/* timeouts in the ANNOUNCE state mean no conflicting ARP
		   packets have been received, so we can progress through
		   the states */
		if (nclaims < ANNOUNCE_NUM) {
			nclaims++;
			debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
				   nclaims, eth_get_name(), &ip);
			arp_raw_request(ip, net_ethaddr, ip);
			timeout_ms = ANNOUNCE_INTERVAL * 1000;
		} else {
			/* Switch to monitor state */
			state = MONITOR;
			printf("Successfully assigned %pI4\n", &ip);
			net_copy_ip(&net_ip, &ip);
			ready = 1;
			conflicts = 0;
			timeout_ms = -1;
			/* Never timeout in the monitor state */
			net_set_timeout_handler(0, NULL);

			/* NOTE: all other exit paths should deconfig ... */
			net_set_state(NETLOOP_SUCCESS);
			return;
		}
		break;
	case DEFEND:
		/* We won!  No ARP replies, so just go back to monitor */
		state = MONITOR;
		timeout_ms = -1;
		conflicts = 0;
		break;
	default:
		/* Invalid, should never happen.  Restart the whole protocol */
		state = PROBE;
		ip = pick();
		timeout_ms = 0;
		nprobes = 0;
		nclaims = 0;
		break;
	}
	configure_wait();
}

void link_local_receive_arp(struct arp_hdr *arp, int len)
{
	int source_ip_conflict;
	int target_ip_conflict;
	struct in_addr null_ip = {.s_addr = 0};

	if (state == DISABLED)
		return;

	/* We need to adjust the timeout in case we didn't receive a
	   conflicting packet. */
	if (timeout_ms > 0) {
		unsigned diff = deadline_ms - MONOTONIC_MS();
		if ((int)(diff) < 0) {
			/* Current time is greater than the expected timeout
			   time. This should never happen */
			debug_cond(DEBUG_LL_STATE,
				   "missed an expected timeout\n");
			timeout_ms = 0;
		} else {
			debug_cond(DEBUG_INT_STATE, "adjusting timeout\n");
			timeout_ms = diff | 1; /* never 0 */
		}
	}
#if 0
 /* XXX Don't bother with ethernet link just yet */
	if ((fds[0].revents & POLLIN) == 0) {
		if (fds[0].revents & POLLERR) {
			/*
			 * FIXME: links routinely go down;
			 */
			bb_error_msg("iface %s is down", eth_get_name());
			if (ready)
				run(argv, "deconfig", &ip);
			return EXIT_FAILURE;
		}
		continue;
	}
#endif

	debug_cond(DEBUG_INT_STATE, "%s recv arp type=%d, op=%d,\n",
		   eth_get_name(), ntohs(arp->ar_pro),
		   ntohs(arp->ar_op));
	debug_cond(DEBUG_INT_STATE, "\tsource=%pM %pI4\n",
		   &arp->ar_sha,
		   &arp->ar_spa);
	debug_cond(DEBUG_INT_STATE, "\ttarget=%pM %pI4\n",
		   &arp->ar_tha,
		   &arp->ar_tpa);

	if (arp->ar_op != htons(ARPOP_REQUEST) &&
	    arp->ar_op != htons(ARPOP_REPLY)) {
		configure_wait();
		return;
	}

	source_ip_conflict = 0;
	target_ip_conflict = 0;

	if (memcmp(&arp->ar_spa, &ip, ARP_PLEN) == 0 &&
	    memcmp(&arp->ar_sha, net_ethaddr, ARP_HLEN) != 0)
		source_ip_conflict = 1;

	/*
	 * According to RFC 3927, section 2.2.1:
	 * Check if packet is an ARP probe by checking for a null source IP
	 * then check that target IP is equal to ours and source hw addr
	 * is not equal to ours. This condition should cause a conflict only
	 * during probe.
	 */
	if (arp->ar_op == htons(ARPOP_REQUEST) &&
	    memcmp(&arp->ar_spa, &null_ip, ARP_PLEN) == 0 &&
	    memcmp(&arp->ar_tpa, &ip, ARP_PLEN) == 0 &&
	    memcmp(&arp->ar_sha, net_ethaddr, ARP_HLEN) != 0) {
		target_ip_conflict = 1;
	}

	debug_cond(DEBUG_NET_PKT,
		   "state = %d, source ip conflict = %d, target ip conflict = "
		   "%d\n", state, source_ip_conflict, target_ip_conflict);
	switch (state) {
	case PROBE:
	case ANNOUNCE:
		/* When probing or announcing, check for source IP conflicts
		   and other hosts doing ARP probes (target IP conflicts). */
		if (source_ip_conflict || target_ip_conflict) {
			conflicts++;
			state = PROBE;
			if (conflicts >= MAX_CONFLICTS) {
				debug("%s ratelimit\n", eth_get_name());
				timeout_ms = RATE_LIMIT_INTERVAL * 1000;
				state = RATE_LIMIT_PROBE;
			}

			/* restart the whole protocol */
			ip = pick();
			timeout_ms = 0;
			nprobes = 0;
			nclaims = 0;
		}
		break;
	case MONITOR:
		/* If a conflict, we try to defend with a single ARP probe */
		if (source_ip_conflict) {
			debug("monitor conflict -- defending\n");
			state = DEFEND;
			timeout_ms = DEFEND_INTERVAL * 1000;
			arp_raw_request(ip, net_ethaddr, ip);
		}
		break;
	case DEFEND:
		/* Well, we tried.  Start over (on conflict) */
		if (source_ip_conflict) {
			state = PROBE;
			debug("defend conflict -- starting over\n");
			ready = 0;
			net_ip.s_addr = 0;

			/* restart the whole protocol */
			ip = pick();
			timeout_ms = 0;
			nprobes = 0;
			nclaims = 0;
		}
		break;
	default:
		/* Invalid, should never happen.  Restart the whole protocol */
		debug("invalid state -- starting over\n");
		state = PROBE;
		ip = pick();
		timeout_ms = 0;
		nprobes = 0;
		nclaims = 0;
		break;
	}
	configure_wait();
}
Commit	Line	Data
d22c338e JH	1	/*
	2	* RFC3927 ZeroConf IPv4 Link-Local addressing
	3	* (see <http://www.zeroconf.org/>)
	4	*
	5	* Copied from BusyBox - networking/zcip.c
	6	*
	7	* Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com)
	8	* Copyright (C) 2004 by David Brownell
	9	* Copyright (C) 2010 by Joe Hershberger
	10	*
	11	* Licensed under the GPL v2 or later
	12	*/
	13
	14	#include <common.h>
	15	#include <net.h>
	16	#include "arp.h"
	17	#include "net_rand.h"
	18
	19	/* We don't need more than 32 bits of the counter */
	20	#define MONOTONIC_MS() ((unsigned)get_timer(0) * (1000 / CONFIG_SYS_HZ))
	21
	22	enum {
	23	/* 169.254.0.0 */
	24	LINKLOCAL_ADDR = 0xa9fe0000,
	25
	26	IN_CLASSB_NET = 0xffff0000,
	27	IN_CLASSB_HOST = 0x0000ffff,
	28
	29	/* protocol timeout parameters, specified in seconds */
	30	PROBE_WAIT = 1,
	31	PROBE_MIN = 1,
	32	PROBE_MAX = 2,
	33	PROBE_NUM = 3,
	34	MAX_CONFLICTS = 10,
	35	RATE_LIMIT_INTERVAL = 60,
	36	ANNOUNCE_WAIT = 2,
	37	ANNOUNCE_NUM = 2,
	38	ANNOUNCE_INTERVAL = 2,
	39	DEFEND_INTERVAL = 10
	40	};
	41
	42	/* States during the configuration process. */
	43	static enum ll_state_t {
	44	PROBE = 0,
	45	RATE_LIMIT_PROBE,
	46	ANNOUNCE,
	47	MONITOR,
	48	DEFEND,
	49	DISABLED
	50	} state = DISABLED;
	51
049a95a7	52	static struct in_addr ip;
d22c338e JH	53	static int timeout_ms = -1;
	54	static unsigned deadline_ms;
	55	static unsigned conflicts;
	56	static unsigned nprobes;
	57	static unsigned nclaims;
	58	static int ready;
99e139d5	59	static unsigned int seed;
d22c338e JH	60
	61	static void link_local_timeout(void);
	62
	63	/**
	64	* Pick a random link local IP address on 169.254/16, except that
	65	* the first and last 256 addresses are reserved.
	66	*/
049a95a7	67	static struct in_addr pick(void)
d22c338e JH	68	{
d22c338e JH	69	unsigned tmp;
049a95a7	70	struct in_addr ip;
d22c338e JH	71
d22c338e JH	72	do {
99e139d5	73	tmp = rand_r(&seed) & IN_CLASSB_HOST;
d22c338e	74	} while (tmp > (IN_CLASSB_HOST - 0x0200));
049a95a7 JH	75	ip.s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
049a95a7 JH	76	return ip;
d22c338e JH	77	}
	78
	79	/**
	80	* Return milliseconds of random delay, up to "secs" seconds.
	81	*/
	82	static inline unsigned random_delay_ms(unsigned secs)
	83	{
99e139d5	84	return rand_r(&seed) % (secs * 1000);
d22c338e JH	85	}
	86
	87	static void configure_wait(void)
	88	{
	89	if (timeout_ms == -1)
	90	return;
	91
	92	/* poll, being ready to adjust current timeout */
	93	if (!timeout_ms)
	94	timeout_ms = random_delay_ms(PROBE_WAIT);
	95
	96	/* set deadline_ms to the point in time when we timeout */
	97	deadline_ms = MONOTONIC_MS() + timeout_ms;
	98
4ef8d53c	99	debug_cond(DEBUG_DEV_PKT, "...wait %d %s nprobes=%u, nclaims=%u\n",
8e7ff677	100	timeout_ms, eth_get_name(), nprobes, nclaims);
d22c338e	101
bc0571fc	102	net_set_timeout_handler(timeout_ms, link_local_timeout);
d22c338e JH	103	}
	104
	105	void link_local_start(void)
	106	{
049a95a7 JH	107	ip = getenv_ip("llipaddr");
	108	if (ip.s_addr != 0 &&
	109	(ntohl(ip.s_addr) & IN_CLASSB_NET) != LINKLOCAL_ADDR) {
d22c338e JH	110	puts("invalid link address");
	111	net_set_state(NETLOOP_FAIL);
	112	return;
	113	}
27a0f038	114	net_netmask.s_addr = htonl(IN_CLASSB_NET);
d22c338e	115
99e139d5	116	seed = seed_mac();
049a95a7	117	if (ip.s_addr == 0)
d22c338e JH	118	ip = pick();
	119
	120	state = PROBE;
	121	timeout_ms = 0;
	122	conflicts = 0;
	123	nprobes = 0;
	124	nclaims = 0;
	125	ready = 0;
	126
	127	configure_wait();
	128	}
	129
	130	static void link_local_timeout(void)
	131	{
	132	switch (state) {
	133	case PROBE:
	134	/* timeouts in the PROBE state mean no conflicting ARP packets
	135	have been received, so we can progress through the states */
	136	if (nprobes < PROBE_NUM) {
049a95a7 JH	137	struct in_addr zero_ip = {.s_addr = 0};
049a95a7 JH	138
d22c338e	139	nprobes++;
4ef8d53c	140	debug_cond(DEBUG_LL_STATE, "probe/%u %s@%pI4\n",
8e7ff677	141	nprobes, eth_get_name(), &ip);
0adb5b76	142	arp_raw_request(zero_ip, net_null_ethaddr, ip);
d22c338e JH	143	timeout_ms = PROBE_MIN * 1000;
	144	timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
	145	} else {
	146	/* Switch to announce state */
	147	state = ANNOUNCE;
	148	nclaims = 0;
4ef8d53c	149	debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
8e7ff677	150	nclaims, eth_get_name(), &ip);
0adb5b76	151	arp_raw_request(ip, net_ethaddr, ip);
d22c338e JH	152	timeout_ms = ANNOUNCE_INTERVAL * 1000;
	153	}
	154	break;
	155	case RATE_LIMIT_PROBE:
	156	/* timeouts in the RATE_LIMIT_PROBE state mean no conflicting
	157	ARP packets have been received, so we can move immediately
	158	to the announce state */
	159	state = ANNOUNCE;
	160	nclaims = 0;
4ef8d53c	161	debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
8e7ff677	162	nclaims, eth_get_name(), &ip);
0adb5b76	163	arp_raw_request(ip, net_ethaddr, ip);
d22c338e JH	164	timeout_ms = ANNOUNCE_INTERVAL * 1000;
	165	break;
	166	case ANNOUNCE:
	167	/* timeouts in the ANNOUNCE state mean no conflicting ARP
	168	packets have been received, so we can progress through
	169	the states */
	170	if (nclaims < ANNOUNCE_NUM) {
	171	nclaims++;
4ef8d53c	172	debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
8e7ff677	173	nclaims, eth_get_name(), &ip);
0adb5b76	174	arp_raw_request(ip, net_ethaddr, ip);
d22c338e JH	175	timeout_ms = ANNOUNCE_INTERVAL * 1000;
	176	} else {
	177	/* Switch to monitor state */
	178	state = MONITOR;
	179	printf("Successfully assigned %pI4\n", &ip);
049a95a7	180	net_copy_ip(&net_ip, &ip);
d22c338e JH	181	ready = 1;
	182	conflicts = 0;
	183	timeout_ms = -1;
	184	/* Never timeout in the monitor state */
bc0571fc	185	net_set_timeout_handler(0, NULL);
d22c338e JH	186
	187	/* NOTE: all other exit paths should deconfig ... */
	188	net_set_state(NETLOOP_SUCCESS);
	189	return;
	190	}
	191	break;
	192	case DEFEND:
	193	/* We won! No ARP replies, so just go back to monitor */
	194	state = MONITOR;
	195	timeout_ms = -1;
	196	conflicts = 0;
	197	break;
	198	default:
	199	/* Invalid, should never happen. Restart the whole protocol */
	200	state = PROBE;
	201	ip = pick();
	202	timeout_ms = 0;
	203	nprobes = 0;
	204	nclaims = 0;
	205	break;
	206	}
	207	configure_wait();
	208	}
	209
	210	void link_local_receive_arp(struct arp_hdr *arp, int len)
	211	{
	212	int source_ip_conflict;
	213	int target_ip_conflict;
049a95a7	214	struct in_addr null_ip = {.s_addr = 0};
d22c338e JH	215
	216	if (state == DISABLED)
	217	return;
	218
	219	/* We need to adjust the timeout in case we didn't receive a
	220	conflicting packet. */
	221	if (timeout_ms > 0) {
	222	unsigned diff = deadline_ms - MONOTONIC_MS();
	223	if ((int)(diff) < 0) {
	224	/* Current time is greater than the expected timeout
	225	time. This should never happen */
4ef8d53c	226	debug_cond(DEBUG_LL_STATE,
8e7ff677	227	"missed an expected timeout\n");
d22c338e JH	228	timeout_ms = 0;
d22c338e JH	229	} else {
4ef8d53c	230	debug_cond(DEBUG_INT_STATE, "adjusting timeout\n");
d22c338e JH	231	timeout_ms = diff \| 1; /* never 0 */
	232	}
	233	}
b6841157	234	#if 0
b6841157	235	/* XXX Don't bother with ethernet link just yet */
d22c338e JH	236	if ((fds[0].revents & POLLIN) == 0) {
d22c338e JH	237	if (fds[0].revents & POLLERR) {
3fe63839 WD	238	/*
	239	* FIXME: links routinely go down;
	240	*/
d22c338e	241	bb_error_msg("iface %s is down", eth_get_name());
8e7ff677	242	if (ready)
d22c338e	243	run(argv, "deconfig", &ip);
d22c338e JH	244	return EXIT_FAILURE;
	245	}
	246	continue;
	247	}
b6841157	248	#endif
d22c338e	249
4ef8d53c	250	debug_cond(DEBUG_INT_STATE, "%s recv arp type=%d, op=%d,\n",
8e7ff677 JH	251	eth_get_name(), ntohs(arp->ar_pro),
8e7ff677 JH	252	ntohs(arp->ar_op));
4ef8d53c	253	debug_cond(DEBUG_INT_STATE, "\tsource=%pM %pI4\n",
8e7ff677 JH	254	&arp->ar_sha,
8e7ff677 JH	255	&arp->ar_spa);
4ef8d53c	256	debug_cond(DEBUG_INT_STATE, "\ttarget=%pM %pI4\n",
8e7ff677 JH	257	&arp->ar_tha,
8e7ff677 JH	258	&arp->ar_tpa);
d22c338e	259
8e7ff677 JH	260	if (arp->ar_op != htons(ARPOP_REQUEST) &&
8e7ff677 JH	261	arp->ar_op != htons(ARPOP_REPLY)) {
d22c338e JH	262	configure_wait();
	263	return;
	264	}
	265
	266	source_ip_conflict = 0;
	267	target_ip_conflict = 0;
	268
0adb5b76 JH	269	if (memcmp(&arp->ar_spa, &ip, ARP_PLEN) == 0 &&
0adb5b76 JH	270	memcmp(&arp->ar_sha, net_ethaddr, ARP_HLEN) != 0)
d22c338e	271	source_ip_conflict = 1;
5da7cf81 JH	272
	273	/*
	274	* According to RFC 3927, section 2.2.1:
	275	* Check if packet is an ARP probe by checking for a null source IP
	276	* then check that target IP is equal to ours and source hw addr
	277	* is not equal to ours. This condition should cause a conflict only
	278	* during probe.
	279	*/
	280	if (arp->ar_op == htons(ARPOP_REQUEST) &&
	281	memcmp(&arp->ar_spa, &null_ip, ARP_PLEN) == 0 &&
	282	memcmp(&arp->ar_tpa, &ip, ARP_PLEN) == 0 &&
0adb5b76	283	memcmp(&arp->ar_sha, net_ethaddr, ARP_HLEN) != 0) {
d22c338e JH	284	target_ip_conflict = 1;
	285	}
	286
4ef8d53c	287	debug_cond(DEBUG_NET_PKT,
8e7ff677 JH	288	"state = %d, source ip conflict = %d, target ip conflict = "
8e7ff677 JH	289	"%d\n", state, source_ip_conflict, target_ip_conflict);
d22c338e JH	290	switch (state) {
	291	case PROBE:
	292	case ANNOUNCE:
	293	/* When probing or announcing, check for source IP conflicts
	294	and other hosts doing ARP probes (target IP conflicts). */
	295	if (source_ip_conflict \|\| target_ip_conflict) {
	296	conflicts++;
	297	state = PROBE;
	298	if (conflicts >= MAX_CONFLICTS) {
	299	debug("%s ratelimit\n", eth_get_name());
	300	timeout_ms = RATE_LIMIT_INTERVAL * 1000;
	301	state = RATE_LIMIT_PROBE;
	302	}
	303
	304	/* restart the whole protocol */
	305	ip = pick();
	306	timeout_ms = 0;
	307	nprobes = 0;
	308	nclaims = 0;
	309	}
	310	break;
	311	case MONITOR:
	312	/* If a conflict, we try to defend with a single ARP probe */
	313	if (source_ip_conflict) {
	314	debug("monitor conflict -- defending\n");
	315	state = DEFEND;
	316	timeout_ms = DEFEND_INTERVAL * 1000;
0adb5b76	317	arp_raw_request(ip, net_ethaddr, ip);
d22c338e JH	318	}
	319	break;
	320	case DEFEND:
	321	/* Well, we tried. Start over (on conflict) */
	322	if (source_ip_conflict) {
	323	state = PROBE;
	324	debug("defend conflict -- starting over\n");
	325	ready = 0;
049a95a7	326	net_ip.s_addr = 0;
d22c338e JH	327
	328	/* restart the whole protocol */
	329	ip = pick();
	330	timeout_ms = 0;
	331	nprobes = 0;
	332	nclaims = 0;
	333	}
	334	break;
	335	default:
	336	/* Invalid, should never happen. Restart the whole protocol */
	337	debug("invalid state -- starting over\n");
	338	state = PROBE;
	339	ip = pick();
	340	timeout_ms = 0;
	341	nprobes = 0;
	342	nclaims = 0;
	343	break;
	344	}
	345	configure_wait();
	346	}