wlan - Rip out all wlan locks part 1/2
[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.
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
54MALLOC_DEFINE(M_80211_DFS, "80211dfs", "802.11 DFS state");
55
56static int ieee80211_nol_timeout = 30*60; /* 30 minutes */
57SYSCTL_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
61static int ieee80211_cac_timeout = 60; /* 60 seconds */
62SYSCTL_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
66void
67ieee80211_dfs_attach(struct ieee80211com *ic)
68{
69 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
70
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71 callout_init(&dfs->nol_timer);
72 callout_init(&dfs->cac_timer);
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73}
74
75void
76ieee80211_dfs_detach(struct ieee80211com *ic)
77{
78 /* NB: we assume no locking is needed */
79 ieee80211_dfs_reset(ic);
80}
81
82void
83ieee80211_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);
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91 for (i = 0; i < ic->ic_nchans; i++)
92 ic->ic_channels[i].ic_state = 0;
93 dfs->lastchan = NULL;
94}
95
96static void
97cac_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
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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 */
150void
151ieee80211_dfs_cac_start(struct ieee80211vap *vap)
152{
153 struct ieee80211com *ic = vap->iv_ic;
154 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
155
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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 */
166void
167ieee80211_dfs_cac_stop(struct ieee80211vap *vap)
168{
169 struct ieee80211com *ic = vap->iv_ic;
170 struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
171
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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
182void
183ieee80211_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
195static void
196dfs_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
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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 */
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229 callout_reset(&dfs->nol_timer, oldest + NOL_TIMEOUT - now,
230 dfs_timeout, ic);
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231 }
232}
233
234static void
235announce_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 */
256void
257ieee80211_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
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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);
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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
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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
330struct ieee80211_channel *
331ieee80211_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}