2 * Copyright (c) 2007-2008 Sam Leffler, Errno Consulting
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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.
26 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
32 * IEEE 802.11 DFS/Radar support.
37 #include <sys/param.h>
38 #include <sys/systm.h>
40 #include <sys/malloc.h>
41 #include <sys/kernel.h>
43 #include <sys/socket.h>
44 #include <sys/sockio.h>
45 #include <sys/endian.h>
46 #include <sys/errno.h>
48 #include <sys/sysctl.h>
51 #include <net/if_var.h>
52 #include <net/if_media.h>
53 #include <net/ethernet.h>
55 #include <netproto/802_11/ieee80211_var.h>
57 static int ieee80211_nol_timeout
= 30*60; /* 30 minutes */
58 SYSCTL_INT(_net_wlan
, OID_AUTO
, nol_timeout
, CTLFLAG_RW
,
59 &ieee80211_nol_timeout
, 0, "NOL timeout (secs)");
60 #define NOL_TIMEOUT msecs_to_ticks(ieee80211_nol_timeout*1000)
62 static int ieee80211_cac_timeout
= 60; /* 60 seconds */
63 SYSCTL_INT(_net_wlan
, OID_AUTO
, cac_timeout
, CTLFLAG_RW
,
64 &ieee80211_cac_timeout
, 0, "CAC timeout (secs)");
65 #define CAC_TIMEOUT msecs_to_ticks(ieee80211_cac_timeout*1000)
68 DFS* In order to facilitate debugging, a couple of operating
69 * modes aside from the default are needed.
71 * 0 - default CAC/NOL behaviour - ie, start CAC, place
72 * channel on NOL list.
73 * 1 - send CAC, but don't change channel or add the channel
75 * 2 - just match on radar, don't send CAC or place channel in
78 static int ieee80211_dfs_debug
= DFS_DBG_NONE
;
81 * This option must not be included in the default kernel
82 * as it allows users to plainly disable CAC/NOL handling.
84 #ifdef IEEE80211_DFS_DEBUG
85 SYSCTL_INT(_net_wlan
, OID_AUTO
, dfs_debug
, CTLFLAG_RW
,
86 &ieee80211_dfs_debug
, 0, "DFS debug behaviour");
90 null_set_quiet(struct ieee80211_node
*ni
, u_int8_t
*quiet_elm
)
96 ieee80211_dfs_attach(struct ieee80211com
*ic
)
98 struct ieee80211_dfs_state
*dfs
= &ic
->ic_dfs
;
100 callout_init_mtx(&dfs
->nol_timer
, IEEE80211_LOCK_OBJ(ic
), 0);
101 callout_init_mtx(&dfs
->cac_timer
, IEEE80211_LOCK_OBJ(ic
), 0);
103 ic
->ic_set_quiet
= null_set_quiet
;
107 ieee80211_dfs_detach(struct ieee80211com
*ic
)
109 /* NB: we assume no locking is needed */
110 ieee80211_dfs_reset(ic
);
114 ieee80211_dfs_reset(struct ieee80211com
*ic
)
116 struct ieee80211_dfs_state
*dfs
= &ic
->ic_dfs
;
119 /* NB: we assume no locking is needed */
120 /* NB: cac_timer should be cleared by the state machine */
121 callout_drain(&dfs
->nol_timer
);
122 for (i
= 0; i
< ic
->ic_nchans
; i
++)
123 ic
->ic_channels
[i
].ic_state
= 0;
124 dfs
->lastchan
= NULL
;
128 cac_timeout(void *arg
)
130 struct ieee80211vap
*vap
= arg
;
131 struct ieee80211com
*ic
= vap
->iv_ic
;
132 struct ieee80211_dfs_state
*dfs
= &ic
->ic_dfs
;
135 IEEE80211_LOCK_ASSERT(ic
);
137 if (vap
->iv_state
!= IEEE80211_S_CAC
) /* NB: just in case */
140 * When radar is detected during a CAC we are woken
141 * up prematurely to switch to a new channel.
142 * Check the channel to decide how to act.
144 if (IEEE80211_IS_CHAN_RADAR(ic
->ic_curchan
)) {
145 ieee80211_notify_cac(ic
, ic
->ic_curchan
,
146 IEEE80211_NOTIFY_CAC_RADAR
);
148 if_printf(vap
->iv_ifp
,
149 "CAC timer on channel %u (%u MHz) stopped due to radar\n",
150 ic
->ic_curchan
->ic_ieee
, ic
->ic_curchan
->ic_freq
);
152 /* XXX clobbers any existing desired channel */
153 /* NB: dfs->newchan may be NULL, that's ok */
154 vap
->iv_des_chan
= dfs
->newchan
;
155 /* XXX recursive lock need ieee80211_new_state_locked */
156 ieee80211_new_state(vap
, IEEE80211_S_SCAN
, 0);
158 if_printf(vap
->iv_ifp
,
159 "CAC timer on channel %u (%u MHz) expired; "
160 "no radar detected\n",
161 ic
->ic_curchan
->ic_ieee
, ic
->ic_curchan
->ic_freq
);
163 * Mark all channels with the current frequency
164 * as having completed CAC; this keeps us from
165 * doing it again until we change channels.
167 for (i
= 0; i
< ic
->ic_nchans
; i
++) {
168 struct ieee80211_channel
*c
= &ic
->ic_channels
[i
];
169 if (c
->ic_freq
== ic
->ic_curchan
->ic_freq
)
170 c
->ic_state
|= IEEE80211_CHANSTATE_CACDONE
;
172 ieee80211_notify_cac(ic
, ic
->ic_curchan
,
173 IEEE80211_NOTIFY_CAC_EXPIRE
);
174 ieee80211_cac_completeswitch(vap
);
179 * Initiate the CAC timer. The driver is responsible
180 * for setting up the hardware to scan for radar on the
181 * channnel, we just handle timing things out.
184 ieee80211_dfs_cac_start(struct ieee80211vap
*vap
)
186 struct ieee80211com
*ic
= vap
->iv_ic
;
187 struct ieee80211_dfs_state
*dfs
= &ic
->ic_dfs
;
189 IEEE80211_LOCK_ASSERT(ic
);
191 callout_reset(&dfs
->cac_timer
, CAC_TIMEOUT
, cac_timeout
, vap
);
192 if_printf(vap
->iv_ifp
, "start %d second CAC timer on channel %u (%u MHz)\n",
193 ticks_to_secs(CAC_TIMEOUT
),
194 ic
->ic_curchan
->ic_ieee
, ic
->ic_curchan
->ic_freq
);
195 ieee80211_notify_cac(ic
, ic
->ic_curchan
, IEEE80211_NOTIFY_CAC_START
);
199 * Clear the CAC timer.
202 ieee80211_dfs_cac_stop(struct ieee80211vap
*vap
)
204 struct ieee80211com
*ic
= vap
->iv_ic
;
205 struct ieee80211_dfs_state
*dfs
= &ic
->ic_dfs
;
207 IEEE80211_LOCK_ASSERT(ic
);
209 /* NB: racey but not important */
210 if (callout_pending(&dfs
->cac_timer
)) {
211 if_printf(vap
->iv_ifp
, "stop CAC timer on channel %u (%u MHz)\n",
212 ic
->ic_curchan
->ic_ieee
, ic
->ic_curchan
->ic_freq
);
213 ieee80211_notify_cac(ic
, ic
->ic_curchan
,
214 IEEE80211_NOTIFY_CAC_STOP
);
216 callout_stop(&dfs
->cac_timer
);
220 ieee80211_dfs_cac_clear(struct ieee80211com
*ic
,
221 const struct ieee80211_channel
*chan
)
225 for (i
= 0; i
< ic
->ic_nchans
; i
++) {
226 struct ieee80211_channel
*c
= &ic
->ic_channels
[i
];
227 if (c
->ic_freq
== chan
->ic_freq
)
228 c
->ic_state
&= ~IEEE80211_CHANSTATE_CACDONE
;
233 dfs_timeout(void *arg
)
235 struct ieee80211com
*ic
= arg
;
236 struct ieee80211_dfs_state
*dfs
= &ic
->ic_dfs
;
237 struct ieee80211_channel
*c
;
240 IEEE80211_LOCK_ASSERT(ic
);
242 now
= oldest
= ticks
;
243 for (i
= 0; i
< ic
->ic_nchans
; i
++) {
244 c
= &ic
->ic_channels
[i
];
245 if (IEEE80211_IS_CHAN_RADAR(c
)) {
246 if (ieee80211_time_after_eq(now
, dfs
->nol_event
[i
]+NOL_TIMEOUT
)) {
247 c
->ic_state
&= ~IEEE80211_CHANSTATE_RADAR
;
248 if (c
->ic_state
& IEEE80211_CHANSTATE_NORADAR
) {
250 * NB: do this here so we get only one
251 * msg instead of one for every channel
254 ic_printf(ic
, "radar on channel %u "
255 "(%u MHz) cleared after timeout\n",
256 c
->ic_ieee
, c
->ic_freq
);
257 /* notify user space */
259 ~IEEE80211_CHANSTATE_NORADAR
;
260 ieee80211_notify_radar(ic
, c
);
262 } else if (dfs
->nol_event
[i
] < oldest
)
263 oldest
= dfs
->nol_event
[i
];
267 /* arrange to process next channel up for a status change */
268 #if defined(__DragonFly__)
269 callout_schedule_dfly(&dfs
->nol_timer
, oldest
+ NOL_TIMEOUT
- now
,
272 callout_schedule(&dfs
->nol_timer
, oldest
+ NOL_TIMEOUT
- now
);
278 announce_radar(struct ieee80211com
*ic
, const struct ieee80211_channel
*curchan
,
279 const struct ieee80211_channel
*newchan
)
282 ic_printf(ic
, "radar detected on channel %u (%u MHz)\n",
283 curchan
->ic_ieee
, curchan
->ic_freq
);
285 ic_printf(ic
, "radar detected on channel %u (%u MHz), "
286 "moving to channel %u (%u MHz)\n",
287 curchan
->ic_ieee
, curchan
->ic_freq
,
288 newchan
->ic_ieee
, newchan
->ic_freq
);
292 * Handle a radar detection event on a channel. The channel is
293 * added to the NOL list and we record the time of the event.
294 * Entries are aged out after NOL_TIMEOUT. If radar was
295 * detected while doing CAC we force a state/channel change.
296 * Otherwise radar triggers a channel switch using the CSA
297 * mechanism (when the channel is the bss channel).
300 ieee80211_dfs_notify_radar(struct ieee80211com
*ic
, struct ieee80211_channel
*chan
)
302 struct ieee80211_dfs_state
*dfs
= &ic
->ic_dfs
;
305 IEEE80211_LOCK_ASSERT(ic
);
308 * If doing DFS debugging (mode 2), don't bother
309 * running the rest of this function.
311 * Simply announce the presence of the radar and continue
314 if (ieee80211_dfs_debug
== DFS_DBG_NOCSANOL
) {
315 announce_radar(ic
, chan
, chan
);
316 ieee80211_notify_radar(ic
, chan
);
321 * Don't mark the channel and don't put it into NOL
322 * if we're doing DFS debugging.
324 if (ieee80211_dfs_debug
== DFS_DBG_NONE
) {
326 * Mark all entries with this frequency. Notify user
327 * space and arrange for notification when the radar
328 * indication is cleared. Then kick the NOL processing
329 * thread if not already running.
332 for (i
= 0; i
< ic
->ic_nchans
; i
++) {
333 struct ieee80211_channel
*c
= &ic
->ic_channels
[i
];
334 if (c
->ic_freq
== chan
->ic_freq
) {
335 c
->ic_state
&= ~IEEE80211_CHANSTATE_CACDONE
;
336 c
->ic_state
|= IEEE80211_CHANSTATE_RADAR
;
337 dfs
->nol_event
[i
] = now
;
340 ieee80211_notify_radar(ic
, chan
);
341 chan
->ic_state
|= IEEE80211_CHANSTATE_NORADAR
;
342 if (!callout_pending(&dfs
->nol_timer
))
343 callout_reset(&dfs
->nol_timer
, NOL_TIMEOUT
,
348 * If radar is detected on the bss channel while
349 * doing CAC; force a state change by scheduling the
350 * callout to be dispatched asap. Otherwise, if this
351 * event is for the bss channel then we must quiet
352 * traffic and schedule a channel switch.
354 * Note this allows us to receive notification about
355 * channels other than the bss channel; not sure
356 * that can/will happen but it's simple to support.
358 if (chan
== ic
->ic_bsschan
) {
359 /* XXX need a way to defer to user app */
362 * Don't flip over to a new channel if
363 * we are currently doing DFS debugging.
365 if (ieee80211_dfs_debug
== DFS_DBG_NONE
)
366 dfs
->newchan
= ieee80211_dfs_pickchannel(ic
);
370 announce_radar(ic
, chan
, dfs
->newchan
);
372 if (callout_pending(&dfs
->cac_timer
))
373 #if defined(__DragonFly__)
374 callout_schedule_dfly(&dfs
->cac_timer
, 0,
376 callout_arg(&dfs
->cac_timer
));
378 callout_schedule(&dfs
->cac_timer
, 0);
380 else if (dfs
->newchan
!= NULL
) {
381 /* XXX mode 1, switch count 2 */
382 /* XXX calculate switch count based on max
383 switch time and beacon interval? */
384 ieee80211_csa_startswitch(ic
, dfs
->newchan
, 1, 2);
387 * Spec says to stop all transmissions and
388 * wait on the current channel for an entry
389 * on the NOL to expire.
392 ic_printf(ic
, "%s: No free channels; waiting for entry "
393 "on NOL to expire\n", __func__
);
397 * Issue rate-limited console msgs.
399 if (dfs
->lastchan
!= chan
) {
400 dfs
->lastchan
= chan
;
402 announce_radar(ic
, chan
, NULL
);
403 } else if (ppsratecheck(&dfs
->lastevent
, &dfs
->cureps
, 1)) {
404 announce_radar(ic
, chan
, NULL
);
409 struct ieee80211_channel
*
410 ieee80211_dfs_pickchannel(struct ieee80211com
*ic
)
412 struct ieee80211_channel
*c
;
417 * Consult the scan cache first.
419 flags
= ic
->ic_curchan
->ic_flags
& IEEE80211_CHAN_ALL
;
421 * XXX if curchan is HT this will never find a channel
422 * XXX 'cuz we scan only legacy channels
424 c
= ieee80211_scan_pickchannel(ic
, flags
);
428 * No channel found in scan cache; select a compatible
429 * one at random (skipping channels where radar has
432 get_random_bytes(&v
, sizeof(v
));
434 for (i
= v
; i
< ic
->ic_nchans
; i
++) {
435 c
= &ic
->ic_channels
[i
];
436 if (!IEEE80211_IS_CHAN_RADAR(c
) &&
437 (c
->ic_flags
& flags
) == flags
)
440 for (i
= 0; i
< v
; i
++) {
441 c
= &ic
->ic_channels
[i
];
442 if (!IEEE80211_IS_CHAN_RADAR(c
) &&
443 (c
->ic_flags
& flags
) == flags
)
446 ic_printf(ic
, "HELP, no channel located to switch to!\n");