[dragonfly.git] / sys / netproto / 802_11 / wlan / ieee80211_dfs.c

/*-
 * Copyright (c) 2007-2008 Sam Leffler, Errno Consulting
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $FreeBSD: head/sys/net80211/ieee80211_dfs.c 196785 2009-09-03 16:29:02Z sam $
 * $DragonFly$
 */

/*
 * IEEE 802.11 DFS/Radar support.
 */
#include "opt_inet.h"
#include "opt_wlan.h"

#include <sys/param.h>
#include <sys/systm.h> 
#include <sys/mbuf.h>   
#include <sys/malloc.h>
#include <sys/kernel.h>

#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/if_media.h>
#include <net/route.h>

#include <netproto/802_11/ieee80211_var.h>

MALLOC_DEFINE(M_80211_DFS, "80211dfs", "802.11 DFS state");

static	int ieee80211_nol_timeout = 30*60;		/* 30 minutes */
SYSCTL_INT(_net_wlan, OID_AUTO, nol_timeout, CTLFLAG_RW,
	&ieee80211_nol_timeout, 0, "NOL timeout (secs)");
#define	NOL_TIMEOUT	msecs_to_ticks(ieee80211_nol_timeout*1000)

static	int ieee80211_cac_timeout = 60;		/* 60 seconds */
SYSCTL_INT(_net_wlan, OID_AUTO, cac_timeout, CTLFLAG_RW,
	&ieee80211_cac_timeout, 0, "CAC timeout (secs)");
#define	CAC_TIMEOUT	msecs_to_ticks(ieee80211_cac_timeout*1000)

void
ieee80211_dfs_attach(struct ieee80211com *ic)
{
	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;

	callout_init(&dfs->nol_timer);
	callout_init(&dfs->cac_timer);
}

void
ieee80211_dfs_detach(struct ieee80211com *ic)
{
	/* NB: we assume no locking is needed */
	ieee80211_dfs_reset(ic);
}

void
ieee80211_dfs_reset(struct ieee80211com *ic)
{
	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	int i;

	/* NB: we assume no locking is needed */
	/* NB: cac_timer should be cleared by the state machine */
	callout_stop(&dfs->nol_timer);
	for (i = 0; i < ic->ic_nchans; i++)
		ic->ic_channels[i].ic_state = 0;
	dfs->lastchan = NULL;
}

static void
cac_timeout(void *arg)
{
	struct ieee80211vap *vap = arg;
	struct ieee80211com *ic = vap->iv_ic;
	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	int i;

	if (vap->iv_state != IEEE80211_S_CAC)	/* NB: just in case */
		return;
	/*
	 * When radar is detected during a CAC we are woken
	 * up prematurely to switch to a new channel.
	 * Check the channel to decide how to act.
	 */
	if (IEEE80211_IS_CHAN_RADAR(ic->ic_curchan)) {
		ieee80211_notify_cac(ic, ic->ic_curchan,
		    IEEE80211_NOTIFY_CAC_RADAR);

		if_printf(vap->iv_ifp,
		    "CAC timer on channel %u (%u MHz) stopped due to radar\n",
		    ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);

		/* XXX clobbers any existing desired channel */
		/* NB: dfs->newchan may be NULL, that's ok */
		vap->iv_des_chan = dfs->newchan;
		/* XXX recursive lock need ieee80211_new_state_locked */
		ieee80211_new_state(vap, IEEE80211_S_SCAN, 0);
	} else {
		if_printf(vap->iv_ifp,
		    "CAC timer on channel %u (%u MHz) expired; "
		    "no radar detected\n",
		    ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
		/*
		 * Mark all channels with the current frequency
		 * as having completed CAC; this keeps us from
		 * doing it again until we change channels.
		 */
		for (i = 0; i < ic->ic_nchans; i++) {
			struct ieee80211_channel *c = &ic->ic_channels[i];
			if (c->ic_freq == ic->ic_curchan->ic_freq)
				c->ic_state |= IEEE80211_CHANSTATE_CACDONE;
		}
		ieee80211_notify_cac(ic, ic->ic_curchan,
		    IEEE80211_NOTIFY_CAC_EXPIRE);
		ieee80211_cac_completeswitch(vap);
	}
}

/*
 * Initiate the CAC timer.  The driver is responsible
 * for setting up the hardware to scan for radar on the
 * channnel, we just handle timing things out.
 */
void
ieee80211_dfs_cac_start(struct ieee80211vap *vap)
{
	struct ieee80211com *ic = vap->iv_ic;
	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;

	callout_reset(&dfs->cac_timer, CAC_TIMEOUT, cac_timeout, vap);
	if_printf(vap->iv_ifp, "start %d second CAC timer on channel %u (%u MHz)\n",
	    ticks_to_secs(CAC_TIMEOUT),
	    ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
	ieee80211_notify_cac(ic, ic->ic_curchan, IEEE80211_NOTIFY_CAC_START);
}

/*
 * Clear the CAC timer.
 */
void
ieee80211_dfs_cac_stop(struct ieee80211vap *vap)
{
	struct ieee80211com *ic = vap->iv_ic;
	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;

	/* NB: racey but not important */
	if (callout_pending(&dfs->cac_timer)) {
		if_printf(vap->iv_ifp, "stop CAC timer on channel %u (%u MHz)\n",
		    ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
		ieee80211_notify_cac(ic, ic->ic_curchan,
		    IEEE80211_NOTIFY_CAC_STOP);
	}
	callout_stop(&dfs->cac_timer);
}

void
ieee80211_dfs_cac_clear(struct ieee80211com *ic,
	const struct ieee80211_channel *chan)
{
	int i;

	for (i = 0; i < ic->ic_nchans; i++) {
		struct ieee80211_channel *c = &ic->ic_channels[i];
		if (c->ic_freq == chan->ic_freq)
			c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE;
	}
}

static void
dfs_timeout(void *arg)
{
	struct ieee80211com *ic = arg;
	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	struct ieee80211_channel *c;
	int i, oldest, now;

	now = oldest = ticks;
	for (i = 0; i < ic->ic_nchans; i++) {
		c = &ic->ic_channels[i];
		if (IEEE80211_IS_CHAN_RADAR(c)) {
			if (time_after_eq(now, dfs->nol_event[i]+NOL_TIMEOUT)) {
				c->ic_state &= ~IEEE80211_CHANSTATE_RADAR;
				if (c->ic_state & IEEE80211_CHANSTATE_NORADAR) {
					/*
					 * NB: do this here so we get only one
					 * msg instead of one for every channel
					 * table entry.
					 */
					if_printf(ic->ic_ifp, "radar on channel"
					    " %u (%u MHz) cleared after timeout\n",
					    c->ic_ieee, c->ic_freq);
					/* notify user space */
					c->ic_state &=
					    ~IEEE80211_CHANSTATE_NORADAR;
					ieee80211_notify_radar(ic, c);
				}
			} else if (dfs->nol_event[i] < oldest)
				oldest = dfs->nol_event[i];
		}
	}
	if (oldest != now) {
		/* arrange to process next channel up for a status change */
		callout_reset(&dfs->nol_timer, oldest + NOL_TIMEOUT - now,
		    dfs_timeout, ic);
	}
}

static void
announce_radar(struct ifnet *ifp, const struct ieee80211_channel *curchan,
	const struct ieee80211_channel *newchan)
{
	if (newchan == NULL)
		if_printf(ifp, "radar detected on channel %u (%u MHz)\n",
		    curchan->ic_ieee, curchan->ic_freq);
	else
		if_printf(ifp, "radar detected on channel %u (%u MHz), "
		    "moving to channel %u (%u MHz)\n",
		    curchan->ic_ieee, curchan->ic_freq,
		    newchan->ic_ieee, newchan->ic_freq);
}

/*
 * Handle a radar detection event on a channel. The channel is
 * added to the NOL list and we record the time of the event.
 * Entries are aged out after NOL_TIMEOUT.  If radar was
 * detected while doing CAC we force a state/channel change.
 * Otherwise radar triggers a channel switch using the CSA
 * mechanism (when the channel is the bss channel).
 */
void
ieee80211_dfs_notify_radar(struct ieee80211com *ic, struct ieee80211_channel *chan)
{
	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	int i, now;

	/*
	 * Mark all entries with this frequency.  Notify user
	 * space and arrange for notification when the radar
	 * indication is cleared.  Then kick the NOL processing
	 * thread if not already running.
	 */
	now = ticks;
	for (i = 0; i < ic->ic_nchans; i++) {
		struct ieee80211_channel *c = &ic->ic_channels[i];
		if (c->ic_freq == chan->ic_freq) {
			c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE;
			c->ic_state |= IEEE80211_CHANSTATE_RADAR;
			dfs->nol_event[i] = now;
		}
	}
	ieee80211_notify_radar(ic, chan);
	chan->ic_state |= IEEE80211_CHANSTATE_NORADAR;
	if (!callout_pending(&dfs->nol_timer))
		callout_reset(&dfs->nol_timer, NOL_TIMEOUT, dfs_timeout, ic);

	/*
	 * If radar is detected on the bss channel while
	 * doing CAC; force a state change by scheduling the
	 * callout to be dispatched asap.  Otherwise, if this
	 * event is for the bss channel then we must quiet
	 * traffic and schedule a channel switch.
	 *
	 * Note this allows us to receive notification about
	 * channels other than the bss channel; not sure
	 * that can/will happen but it's simple to support.
	 */
	if (chan == ic->ic_bsschan) {
		/* XXX need a way to defer to user app */
		dfs->newchan = ieee80211_dfs_pickchannel(ic);

		announce_radar(ic->ic_ifp, chan, dfs->newchan);

#ifdef notyet
		if (callout_pending(&dfs->cac_timer))
			callout_reset(&dfs->cac_timer, 0, cac_timeout, vap);
		else if (dfs->newchan != NULL) {
			/* XXX mode 1, switch count 2 */
			/* XXX calculate switch count based on max
			  switch time and beacon interval? */
			ieee80211_csa_startswitch(ic, dfs->newchan, 1, 2);
		} else {
			/*
			 * Spec says to stop all transmissions and
			 * wait on the current channel for an entry
			 * on the NOL to expire.
			 */
			/*XXX*/
		}
#endif
	} else {
		/*
		 * Issue rate-limited console msgs.
		 */
		if (dfs->lastchan != chan) {
			dfs->lastchan = chan;
			dfs->cureps = 0;
			announce_radar(ic->ic_ifp, chan, NULL);
		} else if (ppsratecheck(&dfs->lastevent, &dfs->cureps, 1)) {
			announce_radar(ic->ic_ifp, chan, NULL);
		}
	}
}

struct ieee80211_channel *
ieee80211_dfs_pickchannel(struct ieee80211com *ic)
{
	struct ieee80211_channel *c;
	int i, flags;
	uint16_t v;

	/*
	 * Consult the scan cache first.
	 */
	flags = ic->ic_curchan->ic_flags & IEEE80211_CHAN_ALL;
	/*
	 * XXX if curchan is HT this will never find a channel
	 * XXX 'cuz we scan only legacy channels
	 */
	c = ieee80211_scan_pickchannel(ic, flags);
	if (c != NULL)
		return c;
	/*
	 * No channel found in scan cache; select a compatible
	 * one at random (skipping channels where radar has
	 * been detected).
	 */
	get_random_bytes(&v, sizeof(v));
	v %= ic->ic_nchans;
	for (i = v; i < ic->ic_nchans; i++) {
		c = &ic->ic_channels[i];
		if (!IEEE80211_IS_CHAN_RADAR(c) &&
		   (c->ic_flags & flags) == flags)
			return c;
	}
	for (i = 0; i < v; i++) {
		c = &ic->ic_channels[i];
		if (!IEEE80211_IS_CHAN_RADAR(c) &&
		   (c->ic_flags & flags) == flags)
			return c;
	}
	if_printf(ic->ic_ifp, "HELP, no channel located to switch to!\n");
	return NULL;
}
Commit	Line	Data
32176cfd RP	1	/*-
	2	* Copyright (c) 2007-2008 Sam Leffler, Errno Consulting
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	*
	14	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	15	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	16	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	17	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	18	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	19	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	20	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	21	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	22	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	23	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	24	*
	25	* $FreeBSD: head/sys/net80211/ieee80211_dfs.c 196785 2009-09-03 16:29:02Z sam $
	26	* $DragonFly$
	27	*/
	28
	29	/*
	30	* IEEE 802.11 DFS/Radar support.
	31	*/
	32	#include "opt_inet.h"
	33	#include "opt_wlan.h"
	34
	35	#include <sys/param.h>
	36	#include <sys/systm.h>
	37	#include <sys/mbuf.h>
	38	#include <sys/malloc.h>
	39	#include <sys/kernel.h>
	40
	41	#include <sys/socket.h>
	42	#include <sys/sockio.h>
	43	#include <sys/endian.h>
	44	#include <sys/errno.h>
	45	#include <sys/proc.h>
	46	#include <sys/sysctl.h>
	47
	48	#include <net/if.h>
	49	#include <net/if_media.h>
	50	#include <net/route.h>
	51
	52	#include <netproto/802_11/ieee80211_var.h>
	53
	54	MALLOC_DEFINE(M_80211_DFS, "80211dfs", "802.11 DFS state");
	55
	56	static int ieee80211_nol_timeout = 3060; / 30 minutes */
	57	SYSCTL_INT(_net_wlan, OID_AUTO, nol_timeout, CTLFLAG_RW,
	58	&ieee80211_nol_timeout, 0, "NOL timeout (secs)");
	59	#define NOL_TIMEOUT msecs_to_ticks(ieee80211_nol_timeout*1000)
	60
	61	static int ieee80211_cac_timeout = 60; /* 60 seconds */
	62	SYSCTL_INT(_net_wlan, OID_AUTO, cac_timeout, CTLFLAG_RW,
	63	&ieee80211_cac_timeout, 0, "CAC timeout (secs)");
	64	#define CAC_TIMEOUT msecs_to_ticks(ieee80211_cac_timeout*1000)
65
66	void
67	ieee80211_dfs_attach(struct ieee80211com *ic)
68	{
69	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
70
22603758 RP	71	callout_init(&dfs->nol_timer);
22603758 RP	72	callout_init(&dfs->cac_timer);
32176cfd RP	73	}
	74
	75	void
	76	ieee80211_dfs_detach(struct ieee80211com *ic)
	77	{
	78	/* NB: we assume no locking is needed */
	79	ieee80211_dfs_reset(ic);
	80	}
	81
	82	void
	83	ieee80211_dfs_reset(struct ieee80211com *ic)
	84	{
	85	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	86	int i;
	87
	88	/* NB: we assume no locking is needed */
	89	/* NB: cac_timer should be cleared by the state machine */
dfcf81fd	90	callout_stop(&dfs->nol_timer);
32176cfd RP	91	for (i = 0; i < ic->ic_nchans; i++)
	92	ic->ic_channels[i].ic_state = 0;
	93	dfs->lastchan = NULL;
	94	}
	95
	96	static void
	97	cac_timeout(void *arg)
	98	{
	99	struct ieee80211vap *vap = arg;
	100	struct ieee80211com *ic = vap->iv_ic;
	101	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	102	int i;
	103
32176cfd RP	104	if (vap->iv_state != IEEE80211_S_CAC) /* NB: just in case */
	105	return;
	106	/*
	107	* When radar is detected during a CAC we are woken
	108	* up prematurely to switch to a new channel.
	109	* Check the channel to decide how to act.
	110	*/
	111	if (IEEE80211_IS_CHAN_RADAR(ic->ic_curchan)) {
	112	ieee80211_notify_cac(ic, ic->ic_curchan,
	113	IEEE80211_NOTIFY_CAC_RADAR);
	114
	115	if_printf(vap->iv_ifp,
	116	"CAC timer on channel %u (%u MHz) stopped due to radar\n",
	117	ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
	118
	119	/* XXX clobbers any existing desired channel */
	120	/* NB: dfs->newchan may be NULL, that's ok */
	121	vap->iv_des_chan = dfs->newchan;
	122	/* XXX recursive lock need ieee80211_new_state_locked */
	123	ieee80211_new_state(vap, IEEE80211_S_SCAN, 0);
	124	} else {
	125	if_printf(vap->iv_ifp,
	126	"CAC timer on channel %u (%u MHz) expired; "
	127	"no radar detected\n",
	128	ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
	129	/*
	130	* Mark all channels with the current frequency
	131	* as having completed CAC; this keeps us from
	132	* doing it again until we change channels.
	133	*/
	134	for (i = 0; i < ic->ic_nchans; i++) {
	135	struct ieee80211_channel *c = &ic->ic_channels[i];
	136	if (c->ic_freq == ic->ic_curchan->ic_freq)
	137	c->ic_state \|= IEEE80211_CHANSTATE_CACDONE;
	138	}
	139	ieee80211_notify_cac(ic, ic->ic_curchan,
	140	IEEE80211_NOTIFY_CAC_EXPIRE);
	141	ieee80211_cac_completeswitch(vap);
	142	}
	143	}
	144
	145	/*
	146	* Initiate the CAC timer. The driver is responsible
	147	* for setting up the hardware to scan for radar on the
	148	* channnel, we just handle timing things out.
	149	*/
	150	void
	151	ieee80211_dfs_cac_start(struct ieee80211vap *vap)
	152	{
	153	struct ieee80211com *ic = vap->iv_ic;
	154	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	155
32176cfd RP	156	callout_reset(&dfs->cac_timer, CAC_TIMEOUT, cac_timeout, vap);
	157	if_printf(vap->iv_ifp, "start %d second CAC timer on channel %u (%u MHz)\n",
	158	ticks_to_secs(CAC_TIMEOUT),
	159	ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
	160	ieee80211_notify_cac(ic, ic->ic_curchan, IEEE80211_NOTIFY_CAC_START);
	161	}
	162
	163	/*
	164	* Clear the CAC timer.
	165	*/
	166	void
	167	ieee80211_dfs_cac_stop(struct ieee80211vap *vap)
	168	{
	169	struct ieee80211com *ic = vap->iv_ic;
	170	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	171
32176cfd RP	172	/* NB: racey but not important */
	173	if (callout_pending(&dfs->cac_timer)) {
	174	if_printf(vap->iv_ifp, "stop CAC timer on channel %u (%u MHz)\n",
	175	ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
	176	ieee80211_notify_cac(ic, ic->ic_curchan,
	177	IEEE80211_NOTIFY_CAC_STOP);
	178	}
	179	callout_stop(&dfs->cac_timer);
	180	}
	181
	182	void
	183	ieee80211_dfs_cac_clear(struct ieee80211com *ic,
	184	const struct ieee80211_channel *chan)
	185	{
	186	int i;
	187
	188	for (i = 0; i < ic->ic_nchans; i++) {
	189	struct ieee80211_channel *c = &ic->ic_channels[i];
	190	if (c->ic_freq == chan->ic_freq)
	191	c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE;
	192	}
	193	}
	194
	195	static void
	196	dfs_timeout(void *arg)
	197	{
	198	struct ieee80211com *ic = arg;
	199	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	200	struct ieee80211_channel *c;
	201	int i, oldest, now;
	202
32176cfd RP	203	now = oldest = ticks;
	204	for (i = 0; i < ic->ic_nchans; i++) {
	205	c = &ic->ic_channels[i];
	206	if (IEEE80211_IS_CHAN_RADAR(c)) {
	207	if (time_after_eq(now, dfs->nol_event[i]+NOL_TIMEOUT)) {
	208	c->ic_state &= ~IEEE80211_CHANSTATE_RADAR;
	209	if (c->ic_state & IEEE80211_CHANSTATE_NORADAR) {
	210	/*
	211	* NB: do this here so we get only one
	212	* msg instead of one for every channel
	213	* table entry.
	214	*/
	215	if_printf(ic->ic_ifp, "radar on channel"
	216	" %u (%u MHz) cleared after timeout\n",
	217	c->ic_ieee, c->ic_freq);
	218	/* notify user space */
	219	c->ic_state &=
	220	~IEEE80211_CHANSTATE_NORADAR;
	221	ieee80211_notify_radar(ic, c);
	222	}
	223	} else if (dfs->nol_event[i] < oldest)
	224	oldest = dfs->nol_event[i];
	225	}
	226	}
	227	if (oldest != now) {
	228	/* arrange to process next channel up for a status change */
22603758 RP	229	callout_reset(&dfs->nol_timer, oldest + NOL_TIMEOUT - now,
22603758 RP	230	dfs_timeout, ic);
32176cfd RP	231	}
	232	}
	233
	234	static void
	235	announce_radar(struct ifnet ifp, const struct ieee80211_channel curchan,
	236	const struct ieee80211_channel *newchan)
	237	{
	238	if (newchan == NULL)
	239	if_printf(ifp, "radar detected on channel %u (%u MHz)\n",
	240	curchan->ic_ieee, curchan->ic_freq);
	241	else
	242	if_printf(ifp, "radar detected on channel %u (%u MHz), "
	243	"moving to channel %u (%u MHz)\n",
	244	curchan->ic_ieee, curchan->ic_freq,
	245	newchan->ic_ieee, newchan->ic_freq);
	246	}
	247
	248	/*
	249	* Handle a radar detection event on a channel. The channel is
	250	* added to the NOL list and we record the time of the event.
	251	* Entries are aged out after NOL_TIMEOUT. If radar was
	252	* detected while doing CAC we force a state/channel change.
	253	* Otherwise radar triggers a channel switch using the CSA
	254	* mechanism (when the channel is the bss channel).
	255	*/
	256	void
	257	ieee80211_dfs_notify_radar(struct ieee80211com ic, struct ieee80211_channel chan)
	258	{
	259	struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
	260	int i, now;
	261
32176cfd RP	262	/*
	263	* Mark all entries with this frequency. Notify user
	264	* space and arrange for notification when the radar
	265	* indication is cleared. Then kick the NOL processing
	266	* thread if not already running.
	267	*/
	268	now = ticks;
	269	for (i = 0; i < ic->ic_nchans; i++) {
	270	struct ieee80211_channel *c = &ic->ic_channels[i];
	271	if (c->ic_freq == chan->ic_freq) {
	272	c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE;
	273	c->ic_state \|= IEEE80211_CHANSTATE_RADAR;
	274	dfs->nol_event[i] = now;
	275	}
	276	}
	277	ieee80211_notify_radar(ic, chan);
	278	chan->ic_state \|= IEEE80211_CHANSTATE_NORADAR;
	279	if (!callout_pending(&dfs->nol_timer))
	280	callout_reset(&dfs->nol_timer, NOL_TIMEOUT, dfs_timeout, ic);
	281
	282	/*
	283	* If radar is detected on the bss channel while
	284	* doing CAC; force a state change by scheduling the
	285	* callout to be dispatched asap. Otherwise, if this
	286	* event is for the bss channel then we must quiet
	287	* traffic and schedule a channel switch.
	288	*
	289	* Note this allows us to receive notification about
	290	* channels other than the bss channel; not sure
	291	* that can/will happen but it's simple to support.
	292	*/
	293	if (chan == ic->ic_bsschan) {
	294	/* XXX need a way to defer to user app */
	295	dfs->newchan = ieee80211_dfs_pickchannel(ic);
	296
	297	announce_radar(ic->ic_ifp, chan, dfs->newchan);
	298
22603758	299	#ifdef notyet
32176cfd	300	if (callout_pending(&dfs->cac_timer))
22603758	301	callout_reset(&dfs->cac_timer, 0, cac_timeout, vap);
32176cfd RP	302	else if (dfs->newchan != NULL) {
	303	/* XXX mode 1, switch count 2 */
	304	/* XXX calculate switch count based on max
	305	switch time and beacon interval? */
	306	ieee80211_csa_startswitch(ic, dfs->newchan, 1, 2);
	307	} else {
	308	/*
	309	* Spec says to stop all transmissions and
	310	* wait on the current channel for an entry
	311	* on the NOL to expire.
	312	*/
	313	/XXX/
	314	}
22603758	315	#endif
32176cfd RP	316	} else {
	317	/*
	318	* Issue rate-limited console msgs.
	319	*/
	320	if (dfs->lastchan != chan) {
	321	dfs->lastchan = chan;
	322	dfs->cureps = 0;
	323	announce_radar(ic->ic_ifp, chan, NULL);
	324	} else if (ppsratecheck(&dfs->lastevent, &dfs->cureps, 1)) {
	325	announce_radar(ic->ic_ifp, chan, NULL);
	326	}
	327	}
	328	}
	329
	330	struct ieee80211_channel *
	331	ieee80211_dfs_pickchannel(struct ieee80211com *ic)
	332	{
	333	struct ieee80211_channel *c;
	334	int i, flags;
	335	uint16_t v;
	336
	337	/*
	338	* Consult the scan cache first.
	339	*/
	340	flags = ic->ic_curchan->ic_flags & IEEE80211_CHAN_ALL;
	341	/*
	342	* XXX if curchan is HT this will never find a channel
	343	* XXX 'cuz we scan only legacy channels
	344	*/
	345	c = ieee80211_scan_pickchannel(ic, flags);
	346	if (c != NULL)
	347	return c;
	348	/*
	349	* No channel found in scan cache; select a compatible
	350	* one at random (skipping channels where radar has
	351	* been detected).
	352	*/
	353	get_random_bytes(&v, sizeof(v));
	354	v %= ic->ic_nchans;
	355	for (i = v; i < ic->ic_nchans; i++) {
	356	c = &ic->ic_channels[i];
	357	if (!IEEE80211_IS_CHAN_RADAR(c) &&
	358	(c->ic_flags & flags) == flags)
	359	return c;
	360	}
	361	for (i = 0; i < v; i++) {
	362	c = &ic->ic_channels[i];
	363	if (!IEEE80211_IS_CHAN_RADAR(c) &&
	364	(c->ic_flags & flags) == flags)
	365	return c;
	366	}
	367	if_printf(ic->ic_ifp, "HELP, no channel located to switch to!\n");
	368	return NULL;
	369	}