wlan - Update wlan from Adrian / FreeBSD
[dragonfly.git] / sys / netproto / 802_11 / wlan / ieee80211_dfs.c
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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.
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24 */
25
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26#include <sys/cdefs.h>
27#ifdef __FreeBSD__
28__FBSDID("$FreeBSD$");
29#endif
30
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31/*
32 * IEEE 802.11 DFS/Radar support.
33 */
34#include "opt_inet.h"
35#include "opt_wlan.h"
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/mbuf.h>
085ff963 40#include <sys/malloc.h>
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41#include <sys/kernel.h>
42
43#include <sys/socket.h>
44#include <sys/sockio.h>
45#include <sys/endian.h>
46#include <sys/errno.h>
47#include <sys/proc.h>
48#include <sys/sysctl.h>
49
50#include <net/if.h>
085ff963 51#include <net/if_var.h>
32176cfd 52#include <net/if_media.h>
085ff963 53#include <net/ethernet.h>
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54
55#include <netproto/802_11/ieee80211_var.h>
56
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57static MALLOC_DEFINE(M_80211_DFS, "80211dfs", "802.11 DFS state");
58
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59static int ieee80211_nol_timeout = 30*60; /* 30 minutes */
60SYSCTL_INT(_net_wlan, OID_AUTO, nol_timeout, CTLFLAG_RW,
61 &ieee80211_nol_timeout, 0, "NOL timeout (secs)");
62#define NOL_TIMEOUT msecs_to_ticks(ieee80211_nol_timeout*1000)
63
64static int ieee80211_cac_timeout = 60; /* 60 seconds */
65SYSCTL_INT(_net_wlan, OID_AUTO, cac_timeout, CTLFLAG_RW,
66 &ieee80211_cac_timeout, 0, "CAC timeout (secs)");
67#define CAC_TIMEOUT msecs_to_ticks(ieee80211_cac_timeout*1000)
68
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69/*
70 DFS* In order to facilitate debugging, a couple of operating
71 * modes aside from the default are needed.
72 *
73 * 0 - default CAC/NOL behaviour - ie, start CAC, place
74 * channel on NOL list.
75 * 1 - send CAC, but don't change channel or add the channel
76 * to the NOL list.
77 * 2 - just match on radar, don't send CAC or place channel in
78 * the NOL list.
79 */
80static int ieee80211_dfs_debug = DFS_DBG_NONE;
81
82/*
83 * This option must not be included in the default kernel
84 * as it allows users to plainly disable CAC/NOL handling.
85 */
86#ifdef IEEE80211_DFS_DEBUG
87SYSCTL_INT(_net_wlan, OID_AUTO, dfs_debug, CTLFLAG_RW,
88 &ieee80211_dfs_debug, 0, "DFS debug behaviour");
89#endif
90
91static int
92null_set_quiet(struct ieee80211_node *ni, u_int8_t *quiet_elm)
93{
94 return ENOSYS;
95}
96
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97void
98ieee80211_dfs_attach(struct ieee80211com *ic)
99{
100 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
101
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102 callout_init_mtx(&dfs->nol_timer, IEEE80211_LOCK_OBJ(ic), 0);
103 callout_init_mtx(&dfs->cac_timer, IEEE80211_LOCK_OBJ(ic), 0);
104
105 ic->ic_set_quiet = null_set_quiet;
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106}
107
108void
109ieee80211_dfs_detach(struct ieee80211com *ic)
110{
111 /* NB: we assume no locking is needed */
112 ieee80211_dfs_reset(ic);
113}
114
115void
116ieee80211_dfs_reset(struct ieee80211com *ic)
117{
118 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
119 int i;
120
121 /* NB: we assume no locking is needed */
122 /* NB: cac_timer should be cleared by the state machine */
085ff963 123 callout_drain(&dfs->nol_timer);
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124 for (i = 0; i < ic->ic_nchans; i++)
125 ic->ic_channels[i].ic_state = 0;
126 dfs->lastchan = NULL;
127}
128
129static void
085ff963 130cac_timeout(void *arg)
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131{
132 struct ieee80211vap *vap = arg;
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133 struct ieee80211com *ic = vap->iv_ic;
134 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
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135 int i;
136
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137 IEEE80211_LOCK_ASSERT(ic);
138
139 if (vap->iv_state != IEEE80211_S_CAC) /* NB: just in case */
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140 return;
141 /*
142 * When radar is detected during a CAC we are woken
143 * up prematurely to switch to a new channel.
144 * Check the channel to decide how to act.
145 */
146 if (IEEE80211_IS_CHAN_RADAR(ic->ic_curchan)) {
147 ieee80211_notify_cac(ic, ic->ic_curchan,
148 IEEE80211_NOTIFY_CAC_RADAR);
149
150 if_printf(vap->iv_ifp,
151 "CAC timer on channel %u (%u MHz) stopped due to radar\n",
152 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
153
154 /* XXX clobbers any existing desired channel */
155 /* NB: dfs->newchan may be NULL, that's ok */
156 vap->iv_des_chan = dfs->newchan;
157 /* XXX recursive lock need ieee80211_new_state_locked */
158 ieee80211_new_state(vap, IEEE80211_S_SCAN, 0);
159 } else {
160 if_printf(vap->iv_ifp,
161 "CAC timer on channel %u (%u MHz) expired; "
162 "no radar detected\n",
163 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
164 /*
165 * Mark all channels with the current frequency
166 * as having completed CAC; this keeps us from
167 * doing it again until we change channels.
168 */
169 for (i = 0; i < ic->ic_nchans; i++) {
170 struct ieee80211_channel *c = &ic->ic_channels[i];
171 if (c->ic_freq == ic->ic_curchan->ic_freq)
172 c->ic_state |= IEEE80211_CHANSTATE_CACDONE;
173 }
174 ieee80211_notify_cac(ic, ic->ic_curchan,
175 IEEE80211_NOTIFY_CAC_EXPIRE);
176 ieee80211_cac_completeswitch(vap);
177 }
178}
179
180/*
181 * Initiate the CAC timer. The driver is responsible
182 * for setting up the hardware to scan for radar on the
183 * channnel, we just handle timing things out.
184 */
185void
186ieee80211_dfs_cac_start(struct ieee80211vap *vap)
187{
188 struct ieee80211com *ic = vap->iv_ic;
189 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
190
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191 IEEE80211_LOCK_ASSERT(ic);
192
193 callout_reset(&dfs->cac_timer, CAC_TIMEOUT, cac_timeout, vap);
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194 if_printf(vap->iv_ifp, "start %d second CAC timer on channel %u (%u MHz)\n",
195 ticks_to_secs(CAC_TIMEOUT),
196 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
197 ieee80211_notify_cac(ic, ic->ic_curchan, IEEE80211_NOTIFY_CAC_START);
198}
199
200/*
201 * Clear the CAC timer.
202 */
203void
204ieee80211_dfs_cac_stop(struct ieee80211vap *vap)
205{
206 struct ieee80211com *ic = vap->iv_ic;
207 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
208
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209 IEEE80211_LOCK_ASSERT(ic);
210
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211 /* NB: racey but not important */
212 if (callout_pending(&dfs->cac_timer)) {
213 if_printf(vap->iv_ifp, "stop CAC timer on channel %u (%u MHz)\n",
214 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
215 ieee80211_notify_cac(ic, ic->ic_curchan,
216 IEEE80211_NOTIFY_CAC_STOP);
217 }
218 callout_stop(&dfs->cac_timer);
219}
220
221void
222ieee80211_dfs_cac_clear(struct ieee80211com *ic,
223 const struct ieee80211_channel *chan)
224{
225 int i;
226
227 for (i = 0; i < ic->ic_nchans; i++) {
228 struct ieee80211_channel *c = &ic->ic_channels[i];
229 if (c->ic_freq == chan->ic_freq)
230 c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE;
231 }
232}
233
234static void
085ff963 235dfs_timeout(void *arg)
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236{
237 struct ieee80211com *ic = arg;
238 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
239 struct ieee80211_channel *c;
240 int i, oldest, now;
241
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242 IEEE80211_LOCK_ASSERT(ic);
243
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244 now = oldest = ticks;
245 for (i = 0; i < ic->ic_nchans; i++) {
246 c = &ic->ic_channels[i];
247 if (IEEE80211_IS_CHAN_RADAR(c)) {
248 if (time_after_eq(now, dfs->nol_event[i]+NOL_TIMEOUT)) {
249 c->ic_state &= ~IEEE80211_CHANSTATE_RADAR;
250 if (c->ic_state & IEEE80211_CHANSTATE_NORADAR) {
251 /*
252 * NB: do this here so we get only one
253 * msg instead of one for every channel
254 * table entry.
255 */
256 if_printf(ic->ic_ifp, "radar on channel"
257 " %u (%u MHz) cleared after timeout\n",
258 c->ic_ieee, c->ic_freq);
259 /* notify user space */
260 c->ic_state &=
261 ~IEEE80211_CHANSTATE_NORADAR;
262 ieee80211_notify_radar(ic, c);
263 }
264 } else if (dfs->nol_event[i] < oldest)
265 oldest = dfs->nol_event[i];
266 }
267 }
268 if (oldest != now) {
269 /* arrange to process next channel up for a status change */
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270 callout_schedule_dfly(&dfs->nol_timer, oldest + NOL_TIMEOUT - now,
271 dfs_timeout, ic);
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272 }
273}
274
275static void
276announce_radar(struct ifnet *ifp, const struct ieee80211_channel *curchan,
277 const struct ieee80211_channel *newchan)
278{
279 if (newchan == NULL)
280 if_printf(ifp, "radar detected on channel %u (%u MHz)\n",
281 curchan->ic_ieee, curchan->ic_freq);
282 else
283 if_printf(ifp, "radar detected on channel %u (%u MHz), "
284 "moving to channel %u (%u MHz)\n",
285 curchan->ic_ieee, curchan->ic_freq,
286 newchan->ic_ieee, newchan->ic_freq);
287}
288
289/*
290 * Handle a radar detection event on a channel. The channel is
291 * added to the NOL list and we record the time of the event.
292 * Entries are aged out after NOL_TIMEOUT. If radar was
293 * detected while doing CAC we force a state/channel change.
294 * Otherwise radar triggers a channel switch using the CSA
295 * mechanism (when the channel is the bss channel).
296 */
297void
298ieee80211_dfs_notify_radar(struct ieee80211com *ic, struct ieee80211_channel *chan)
299{
300 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
301 int i, now;
302
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303 IEEE80211_LOCK_ASSERT(ic);
304
32176cfd 305 /*
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306 * If doing DFS debugging (mode 2), don't bother
307 * running the rest of this function.
308 *
309 * Simply announce the presence of the radar and continue
310 * along merrily.
32176cfd 311 */
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312 if (ieee80211_dfs_debug == DFS_DBG_NOCSANOL) {
313 announce_radar(ic->ic_ifp, chan, chan);
314 ieee80211_notify_radar(ic, chan);
315 return;
32176cfd 316 }
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317
318 /*
319 * Don't mark the channel and don't put it into NOL
320 * if we're doing DFS debugging.
321 */
322 if (ieee80211_dfs_debug == DFS_DBG_NONE) {
323 /*
324 * Mark all entries with this frequency. Notify user
325 * space and arrange for notification when the radar
326 * indication is cleared. Then kick the NOL processing
327 * thread if not already running.
328 */
329 now = ticks;
330 for (i = 0; i < ic->ic_nchans; i++) {
331 struct ieee80211_channel *c = &ic->ic_channels[i];
332 if (c->ic_freq == chan->ic_freq) {
333 c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE;
334 c->ic_state |= IEEE80211_CHANSTATE_RADAR;
335 dfs->nol_event[i] = now;
336 }
337 }
338 ieee80211_notify_radar(ic, chan);
339 chan->ic_state |= IEEE80211_CHANSTATE_NORADAR;
340 if (!callout_pending(&dfs->nol_timer))
341 callout_reset(&dfs->nol_timer, NOL_TIMEOUT,
342 dfs_timeout, ic);
47156d48 343 }
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344
345 /*
346 * If radar is detected on the bss channel while
347 * doing CAC; force a state change by scheduling the
348 * callout to be dispatched asap. Otherwise, if this
349 * event is for the bss channel then we must quiet
350 * traffic and schedule a channel switch.
351 *
352 * Note this allows us to receive notification about
353 * channels other than the bss channel; not sure
354 * that can/will happen but it's simple to support.
355 */
356 if (chan == ic->ic_bsschan) {
357 /* XXX need a way to defer to user app */
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358
359 /*
360 * Don't flip over to a new channel if
361 * we are currently doing DFS debugging.
362 */
363 if (ieee80211_dfs_debug == DFS_DBG_NONE)
364 dfs->newchan = ieee80211_dfs_pickchannel(ic);
365 else
366 dfs->newchan = chan;
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367
368 announce_radar(ic->ic_ifp, chan, dfs->newchan);
369
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370 if (callout_pending(&dfs->cac_timer))
371 callout_schedule_dfly(&dfs->cac_timer, 0, cac_timeout, dfs->cac_timer.c_arg);
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372 else if (dfs->newchan != NULL) {
373 /* XXX mode 1, switch count 2 */
374 /* XXX calculate switch count based on max
375 switch time and beacon interval? */
376 ieee80211_csa_startswitch(ic, dfs->newchan, 1, 2);
377 } else {
378 /*
379 * Spec says to stop all transmissions and
380 * wait on the current channel for an entry
381 * on the NOL to expire.
382 */
383 /*XXX*/
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384 if_printf(ic->ic_ifp, "%s: No free channels; waiting for entry "
385 "on NOL to expire\n", __func__);
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386 }
387 } else {
388 /*
389 * Issue rate-limited console msgs.
390 */
391 if (dfs->lastchan != chan) {
392 dfs->lastchan = chan;
393 dfs->cureps = 0;
394 announce_radar(ic->ic_ifp, chan, NULL);
395 } else if (ppsratecheck(&dfs->lastevent, &dfs->cureps, 1)) {
396 announce_radar(ic->ic_ifp, chan, NULL);
397 }
398 }
399}
400
401struct ieee80211_channel *
402ieee80211_dfs_pickchannel(struct ieee80211com *ic)
403{
404 struct ieee80211_channel *c;
405 int i, flags;
406 uint16_t v;
407
408 /*
409 * Consult the scan cache first.
410 */
411 flags = ic->ic_curchan->ic_flags & IEEE80211_CHAN_ALL;
412 /*
413 * XXX if curchan is HT this will never find a channel
414 * XXX 'cuz we scan only legacy channels
415 */
416 c = ieee80211_scan_pickchannel(ic, flags);
417 if (c != NULL)
418 return c;
419 /*
420 * No channel found in scan cache; select a compatible
421 * one at random (skipping channels where radar has
422 * been detected).
423 */
424 get_random_bytes(&v, sizeof(v));
425 v %= ic->ic_nchans;
426 for (i = v; i < ic->ic_nchans; i++) {
427 c = &ic->ic_channels[i];
428 if (!IEEE80211_IS_CHAN_RADAR(c) &&
429 (c->ic_flags & flags) == flags)
430 return c;
431 }
432 for (i = 0; i < v; i++) {
433 c = &ic->ic_channels[i];
434 if (!IEEE80211_IS_CHAN_RADAR(c) &&
435 (c->ic_flags & flags) == flags)
436 return c;
437 }
438 if_printf(ic->ic_ifp, "HELP, no channel located to switch to!\n");
439 return NULL;
440}