1 /*-
2 * Copyright (c) 2002-2008 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
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28
29 /*
30 * IEEE 802.11 scanning support.
31 */
32 #include "opt_wlan.h"
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/proc.h>
37 #include <sys/kernel.h>
38 #include <sys/malloc.h>
39 #include <sys/condvar.h>
40
41 #include <sys/socket.h>
42
43 #include <net/if.h>
44 #include <net/if_var.h>
45 #include <net/if_media.h>
46 #include <net/ethernet.h>
47
48 #include <net80211/ieee80211_var.h>
49
50 #include <net80211/ieee80211_scan_sw.h>
51
52 #include <net/bpf.h>
53
54 struct scan_state {
55 struct ieee80211_scan_state base; /* public state */
56
57 u_int ss_iflags; /* flags used internally */
58 #define ISCAN_MINDWELL 0x0001 /* min dwell time reached */
59 #define ISCAN_DISCARD 0x0002 /* discard rx'd frames */
60 #define ISCAN_CANCEL 0x0004 /* cancel current scan */
61 #define ISCAN_ABORT 0x0008 /* end the scan immediately */
62 #define ISCAN_RUNNING 0x0010 /* scan was started */
63
64 unsigned long ss_chanmindwell; /* min dwell on curchan */
65 unsigned long ss_scanend; /* time scan must stop */
66 u_int ss_duration; /* duration for next scan */
67 struct task ss_scan_start; /* scan start */
68 struct timeout_task ss_scan_curchan; /* scan execution */
69 };
70 #define SCAN_PRIVATE(ss) ((struct scan_state *) ss)
71
72 /*
73 * Amount of time to go off-channel during a background
74 * scan. This value should be large enough to catch most
75 * ap's but short enough that we can return on-channel
76 * before our listen interval expires.
77 *
78 * XXX tunable
79 * XXX check against configured listen interval
80 */
81 #define IEEE80211_SCAN_OFFCHANNEL msecs_to_ticks(150)
82
83 static void scan_curchan(struct ieee80211_scan_state *, unsigned long);
84 static void scan_mindwell(struct ieee80211_scan_state *);
85 static void scan_signal(struct ieee80211_scan_state *, int);
86 static void scan_signal_locked(struct ieee80211_scan_state *, int);
87 static void scan_start(void *, int);
88 static void scan_curchan_task(void *, int);
89 static void scan_end(struct ieee80211_scan_state *, int);
90 static void scan_done(struct ieee80211_scan_state *, int);
91
92 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
93
94 static void
ieee80211_swscan_detach(struct ieee80211com * ic)95 ieee80211_swscan_detach(struct ieee80211com *ic)
96 {
97 struct ieee80211_scan_state *ss = ic->ic_scan;
98
99 if (ss != NULL) {
100 scan_signal(ss, ISCAN_ABORT);
101 ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_start);
102 taskqueue_drain_timeout(ic->ic_tq,
103 &SCAN_PRIVATE(ss)->ss_scan_curchan);
104 KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0,
105 ("scan still running"));
106
107 /*
108 * For now, do the ss_ops detach here rather
109 * than ieee80211_scan_detach().
110 *
111 * I'll figure out how to cleanly split things up
112 * at a later date.
113 */
114 if (ss->ss_ops != NULL) {
115 ss->ss_ops->scan_detach(ss);
116 ss->ss_ops = NULL;
117 }
118 ic->ic_scan = NULL;
119 IEEE80211_FREE(SCAN_PRIVATE(ss), M_80211_SCAN);
120 }
121 }
122
123 static void
ieee80211_swscan_vattach(struct ieee80211vap * vap)124 ieee80211_swscan_vattach(struct ieee80211vap *vap)
125 {
126 /* nothing to do for now */
127 /*
128 * TODO: all of the vap scan calls should be methods!
129 */
130
131 }
132
133 static void
ieee80211_swscan_vdetach(struct ieee80211vap * vap)134 ieee80211_swscan_vdetach(struct ieee80211vap *vap)
135 {
136 struct ieee80211com *ic = vap->iv_ic;
137 struct ieee80211_scan_state *ss = ic->ic_scan;
138
139 IEEE80211_LOCK_ASSERT(ic);
140
141 if (ss != NULL && ss->ss_vap == vap &&
142 (ic->ic_flags & IEEE80211_F_SCAN))
143 scan_signal_locked(ss, ISCAN_ABORT);
144 }
145
146 static void
ieee80211_swscan_set_scan_duration(struct ieee80211vap * vap,u_int duration)147 ieee80211_swscan_set_scan_duration(struct ieee80211vap *vap, u_int duration)
148 {
149 struct ieee80211com *ic = vap->iv_ic;
150 struct ieee80211_scan_state *ss = ic->ic_scan;
151
152 IEEE80211_LOCK_ASSERT(ic);
153
154 /* NB: flush frames rx'd before 1st channel change */
155 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
156 SCAN_PRIVATE(ss)->ss_duration = duration;
157 }
158
159 /*
160 * Start a scan unless one is already going.
161 */
162 static int
ieee80211_swscan_start_scan_locked(const struct ieee80211_scanner * scan,struct ieee80211vap * vap,int flags,u_int duration,u_int mindwell,u_int maxdwell,u_int nssid,const struct ieee80211_scan_ssid ssids[])163 ieee80211_swscan_start_scan_locked(const struct ieee80211_scanner *scan,
164 struct ieee80211vap *vap, int flags, u_int duration,
165 u_int mindwell, u_int maxdwell,
166 u_int nssid, const struct ieee80211_scan_ssid ssids[])
167 {
168 struct ieee80211com *ic = vap->iv_ic;
169 struct ieee80211_scan_state *ss = ic->ic_scan;
170
171 IEEE80211_LOCK_ASSERT(ic);
172
173 if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
174 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
175 "%s: scan inhibited by pending channel change\n", __func__);
176 } else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
177 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
178 "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
179 , __func__
180 , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
181 , duration, mindwell, maxdwell
182 , ieee80211_phymode_name[vap->iv_des_mode]
183 , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
184 , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
185 , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
186 , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
187 , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
188 , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
189 );
190
191 ieee80211_scan_update_locked(vap, scan);
192 if (ss->ss_ops != NULL) {
193 if ((flags & IEEE80211_SCAN_NOSSID) == 0)
194 ieee80211_scan_copy_ssid(vap, ss, nssid, ssids);
195
196 /* NB: top 4 bits for internal use */
197 ss->ss_flags = flags & 0xfff;
198 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
199 vap->iv_stats.is_scan_active++;
200 else
201 vap->iv_stats.is_scan_passive++;
202 if (flags & IEEE80211_SCAN_FLUSH)
203 ss->ss_ops->scan_flush(ss);
204 if (flags & IEEE80211_SCAN_BGSCAN)
205 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
206
207 /* Set duration for this particular scan */
208 ieee80211_swscan_set_scan_duration(vap, duration);
209
210 ss->ss_next = 0;
211 ss->ss_mindwell = mindwell;
212 ss->ss_maxdwell = maxdwell;
213 /* NB: scan_start must be before the scan runtask */
214 ss->ss_ops->scan_start(ss, vap);
215 #ifdef IEEE80211_DEBUG
216 if (ieee80211_msg_scan(vap))
217 ieee80211_scan_dump(ss);
218 #endif /* IEEE80211_DEBUG */
219 ic->ic_flags |= IEEE80211_F_SCAN;
220
221 /* Start scan task */
222 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_start);
223 }
224 return 1;
225 } else {
226 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
227 "%s: %s scan already in progress\n", __func__,
228 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
229 }
230 return 0;
231 }
232
233
234 /*
235 * Start a scan unless one is already going.
236 *
237 * Called without the comlock held; grab the comlock as appropriate.
238 */
239 static int
ieee80211_swscan_start_scan(const struct ieee80211_scanner * scan,struct ieee80211vap * vap,int flags,u_int duration,u_int mindwell,u_int maxdwell,u_int nssid,const struct ieee80211_scan_ssid ssids[])240 ieee80211_swscan_start_scan(const struct ieee80211_scanner *scan,
241 struct ieee80211vap *vap, int flags,
242 u_int duration, u_int mindwell, u_int maxdwell,
243 u_int nssid, const struct ieee80211_scan_ssid ssids[])
244 {
245 struct ieee80211com *ic = vap->iv_ic;
246 int result;
247
248 IEEE80211_UNLOCK_ASSERT(ic);
249
250 IEEE80211_LOCK(ic);
251 result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration,
252 mindwell, maxdwell, nssid, ssids);
253 IEEE80211_UNLOCK(ic);
254
255 return result;
256 }
257
258 /*
259 * Check the scan cache for an ap/channel to use; if that
260 * fails then kick off a new scan.
261 *
262 * Called with the comlock held.
263 *
264 * XXX TODO: split out!
265 */
266 static int
ieee80211_swscan_check_scan(const struct ieee80211_scanner * scan,struct ieee80211vap * vap,int flags,u_int duration,u_int mindwell,u_int maxdwell,u_int nssid,const struct ieee80211_scan_ssid ssids[])267 ieee80211_swscan_check_scan(const struct ieee80211_scanner *scan,
268 struct ieee80211vap *vap, int flags,
269 u_int duration, u_int mindwell, u_int maxdwell,
270 u_int nssid, const struct ieee80211_scan_ssid ssids[])
271 {
272 struct ieee80211com *ic = vap->iv_ic;
273 struct ieee80211_scan_state *ss = ic->ic_scan;
274 int result;
275
276 IEEE80211_LOCK_ASSERT(ic);
277
278 if (ss->ss_ops != NULL) {
279 /* XXX verify ss_ops matches vap->iv_opmode */
280 if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
281 /*
282 * Update the ssid list and mark flags so if
283 * we call start_scan it doesn't duplicate work.
284 */
285 ieee80211_scan_copy_ssid(vap, ss, nssid, ssids);
286 flags |= IEEE80211_SCAN_NOSSID;
287 }
288 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
289 (flags & IEEE80211_SCAN_FLUSH) == 0 &&
290 ieee80211_time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
291 /*
292 * We're not currently scanning and the cache is
293 * deemed hot enough to consult. Lock out others
294 * by marking IEEE80211_F_SCAN while we decide if
295 * something is already in the scan cache we can
296 * use. Also discard any frames that might come
297 * in while temporarily marked as scanning.
298 */
299 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
300 ic->ic_flags |= IEEE80211_F_SCAN;
301
302 /* NB: need to use supplied flags in check */
303 ss->ss_flags = flags & 0xff;
304 result = ss->ss_ops->scan_end(ss, vap);
305
306 ic->ic_flags &= ~IEEE80211_F_SCAN;
307 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
308 if (result) {
309 ieee80211_notify_scan_done(vap);
310 return 1;
311 }
312 }
313 }
314 result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration,
315 mindwell, maxdwell, nssid, ssids);
316
317 return result;
318 }
319
320 /*
321 * Restart a previous scan. If the previous scan completed
322 * then we start again using the existing channel list.
323 */
324 static int
ieee80211_swscan_bg_scan(const struct ieee80211_scanner * scan,struct ieee80211vap * vap,int flags)325 ieee80211_swscan_bg_scan(const struct ieee80211_scanner *scan,
326 struct ieee80211vap *vap, int flags)
327 {
328 struct ieee80211com *ic = vap->iv_ic;
329 struct ieee80211_scan_state *ss = ic->ic_scan;
330
331 /* XXX assert unlocked? */
332 // IEEE80211_UNLOCK_ASSERT(ic);
333
334 IEEE80211_LOCK(ic);
335 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
336 u_int duration;
337 /*
338 * Go off-channel for a fixed interval that is large
339 * enough to catch most ap's but short enough that
340 * we can return on-channel before our listen interval
341 * expires.
342 */
343 duration = IEEE80211_SCAN_OFFCHANNEL;
344
345 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
346 "%s: %s scan, ticks %u duration %u\n", __func__,
347 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
348 ticks, duration);
349
350 ieee80211_scan_update_locked(vap, scan);
351 if (ss->ss_ops != NULL) {
352 ss->ss_vap = vap;
353 /*
354 * A background scan does not select a new sta; it
355 * just refreshes the scan cache. Also, indicate
356 * the scan logic should follow the beacon schedule:
357 * we go off-channel and scan for a while, then
358 * return to the bss channel to receive a beacon,
359 * then go off-channel again. All during this time
360 * we notify the ap we're in power save mode. When
361 * the scan is complete we leave power save mode.
362 * If any beacon indicates there are frames pending
363 * for us then we drop out of power save mode
364 * (and background scan) automatically by way of the
365 * usual sta power save logic.
366 */
367 ss->ss_flags |= IEEE80211_SCAN_NOPICK
368 | IEEE80211_SCAN_BGSCAN
369 | flags
370 ;
371 /* if previous scan completed, restart */
372 if (ss->ss_next >= ss->ss_last) {
373 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
374 vap->iv_stats.is_scan_active++;
375 else
376 vap->iv_stats.is_scan_passive++;
377 /*
378 * NB: beware of the scan cache being flushed;
379 * if the channel list is empty use the
380 * scan_start method to populate it.
381 */
382 ss->ss_next = 0;
383 if (ss->ss_last != 0)
384 ss->ss_ops->scan_restart(ss, vap);
385 else {
386 ss->ss_ops->scan_start(ss, vap);
387 #ifdef IEEE80211_DEBUG
388 if (ieee80211_msg_scan(vap))
389 ieee80211_scan_dump(ss);
390 #endif /* IEEE80211_DEBUG */
391 }
392 }
393 ieee80211_swscan_set_scan_duration(vap, duration);
394 ss->ss_maxdwell = duration;
395 ic->ic_flags |= IEEE80211_F_SCAN;
396 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
397 ieee80211_runtask(ic,
398 &SCAN_PRIVATE(ss)->ss_scan_start);
399 } else {
400 /* XXX msg+stat */
401 }
402 } else {
403 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
404 "%s: %s scan already in progress\n", __func__,
405 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
406 }
407 IEEE80211_UNLOCK(ic);
408
409 /* NB: racey, does it matter? */
410 return (ic->ic_flags & IEEE80211_F_SCAN);
411 }
412
413 /*
414 * Taskqueue work to cancel a scan.
415 *
416 * Note: for offload scan devices, we may want to call into the
417 * driver to try and cancel scanning, however it may not be cancelable.
418 */
419 static void
cancel_scan(struct ieee80211vap * vap,int any,const char * func)420 cancel_scan(struct ieee80211vap *vap, int any, const char *func)
421 {
422 struct ieee80211com *ic = vap->iv_ic;
423 struct ieee80211_scan_state *ss = ic->ic_scan;
424
425 IEEE80211_LOCK(ic);
426 if ((ic->ic_flags & IEEE80211_F_SCAN) &&
427 (any || ss->ss_vap == vap) &&
428 (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
429 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
430 "%s: cancel %s scan\n", func,
431 ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
432 "active" : "passive");
433
434 /* clear bg scan NOPICK */
435 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
436 /* mark cancel request and wake up the scan task */
437 scan_signal_locked(ss, ISCAN_CANCEL);
438 } else {
439 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
440 "%s: called; F_SCAN=%d, vap=%s, CANCEL=%d\n",
441 func,
442 !! (ic->ic_flags & IEEE80211_F_SCAN),
443 (ss->ss_vap == vap ? "match" : "nomatch"),
444 !! (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL));
445 }
446 IEEE80211_UNLOCK(ic);
447 }
448
449 /*
450 * Cancel any scan currently going on for the specified vap.
451 */
452 static void
ieee80211_swscan_cancel_scan(struct ieee80211vap * vap)453 ieee80211_swscan_cancel_scan(struct ieee80211vap *vap)
454 {
455 cancel_scan(vap, 0, __func__);
456 }
457
458 /*
459 * Cancel any scan currently going on.
460 */
461 static void
ieee80211_swscan_cancel_anyscan(struct ieee80211vap * vap)462 ieee80211_swscan_cancel_anyscan(struct ieee80211vap *vap)
463 {
464
465 /* XXX for now - just don't do this per packet. */
466 if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD)
467 return;
468
469 cancel_scan(vap, 1, __func__);
470 }
471
472 /*
473 * Manually switch to the next channel in the channel list.
474 * Provided for drivers that manage scanning themselves
475 * (e.g. for firmware-based devices).
476 */
477 static void
ieee80211_swscan_scan_next(struct ieee80211vap * vap)478 ieee80211_swscan_scan_next(struct ieee80211vap *vap)
479 {
480 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
481
482 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
483
484 /* wake up the scan task */
485 scan_signal(ss, 0);
486 }
487
488 /*
489 * Manually stop a scan that is currently running.
490 * Provided for drivers that are not able to scan single channels
491 * (e.g. for firmware-based devices).
492 */
493 static void
ieee80211_swscan_scan_done(struct ieee80211vap * vap)494 ieee80211_swscan_scan_done(struct ieee80211vap *vap)
495 {
496 struct ieee80211com *ic = vap->iv_ic;
497 struct ieee80211_scan_state *ss = ic->ic_scan;
498
499 IEEE80211_LOCK_ASSERT(ic);
500
501 scan_signal_locked(ss, 0);
502 }
503
504 /*
505 * Probe the current channel, if allowed, while scanning.
506 * If the channel is not marked passive-only then send
507 * a probe request immediately. Otherwise mark state and
508 * listen for beacons on the channel; if we receive something
509 * then we'll transmit a probe request.
510 */
511 static void
ieee80211_swscan_probe_curchan(struct ieee80211vap * vap,int force)512 ieee80211_swscan_probe_curchan(struct ieee80211vap *vap, int force)
513 {
514 struct ieee80211com *ic = vap->iv_ic;
515 struct ieee80211_scan_state *ss = ic->ic_scan;
516 struct ifnet *ifp = vap->iv_ifp;
517 int i;
518
519 /*
520 * Full-offload scan devices don't require this.
521 */
522 if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD)
523 return;
524
525 /*
526 * Send directed probe requests followed by any
527 * broadcast probe request.
528 * XXX remove dependence on ic/vap->iv_bss
529 */
530 for (i = 0; i < ss->ss_nssid; i++)
531 ieee80211_send_probereq(vap->iv_bss,
532 vap->iv_myaddr, ifp->if_broadcastaddr,
533 ifp->if_broadcastaddr,
534 ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
535 if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
536 ieee80211_send_probereq(vap->iv_bss,
537 vap->iv_myaddr, ifp->if_broadcastaddr,
538 ifp->if_broadcastaddr,
539 "", 0);
540 }
541
542 /*
543 * Scan curchan. If this is an active scan and the channel
544 * is not marked passive then send probe request frame(s).
545 * Arrange for the channel change after maxdwell ticks.
546 */
547 static void
scan_curchan(struct ieee80211_scan_state * ss,unsigned long maxdwell)548 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
549 {
550 struct ieee80211vap *vap = ss->ss_vap;
551 struct ieee80211com *ic = ss->ss_ic;
552
553 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
554 "%s: calling; maxdwell=%lu\n",
555 __func__,
556 maxdwell);
557 IEEE80211_LOCK(ic);
558 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
559 ieee80211_probe_curchan(vap, 0);
560 taskqueue_enqueue_timeout(ic->ic_tq,
561 &SCAN_PRIVATE(ss)->ss_scan_curchan, maxdwell);
562 IEEE80211_UNLOCK(ic);
563 }
564
565 static void
scan_signal(struct ieee80211_scan_state * ss,int iflags)566 scan_signal(struct ieee80211_scan_state *ss, int iflags)
567 {
568 struct ieee80211com *ic = ss->ss_ic;
569
570 IEEE80211_UNLOCK_ASSERT(ic);
571
572 IEEE80211_LOCK(ic);
573 scan_signal_locked(ss, iflags);
574 IEEE80211_UNLOCK(ic);
575 }
576
577 static void
scan_signal_locked(struct ieee80211_scan_state * ss,int iflags)578 scan_signal_locked(struct ieee80211_scan_state *ss, int iflags)
579 {
580 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
581 struct timeout_task *scan_task = &ss_priv->ss_scan_curchan;
582 struct ieee80211com *ic = ss->ss_ic;
583
584 IEEE80211_LOCK_ASSERT(ic);
585
586 ss_priv->ss_iflags |= iflags;
587 if (ss_priv->ss_iflags & ISCAN_RUNNING) {
588 if (taskqueue_cancel_timeout(ic->ic_tq, scan_task, NULL) == 0)
589 taskqueue_enqueue_timeout(ic->ic_tq, scan_task, 0);
590 }
591 }
592
593 /*
594 * Handle mindwell requirements completed; initiate a channel
595 * change to the next channel asap.
596 */
597 static void
scan_mindwell(struct ieee80211_scan_state * ss)598 scan_mindwell(struct ieee80211_scan_state *ss)
599 {
600
601 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: called\n",
602 __func__);
603
604 scan_signal(ss, 0);
605 }
606
607 static void
scan_start(void * arg,int pending)608 scan_start(void *arg, int pending)
609 {
610 #define ISCAN_REP (ISCAN_MINDWELL | ISCAN_DISCARD)
611 struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
612 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
613 struct ieee80211vap *vap = ss->ss_vap;
614 struct ieee80211com *ic = ss->ss_ic;
615
616 IEEE80211_LOCK(ic);
617 if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
618 (ss_priv->ss_iflags & ISCAN_ABORT)) {
619 /* Cancelled before we started */
620 scan_done(ss, 0);
621 return;
622 }
623
624 if (ss->ss_next == ss->ss_last) {
625 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
626 "%s: no channels to scan\n", __func__);
627 scan_done(ss, 1);
628 return;
629 }
630
631 /*
632 * Put the station into power save mode.
633 *
634 * This is only required if we're not a full-offload devices;
635 * those devices manage scan/traffic differently.
636 */
637 if (((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0) &&
638 vap->iv_opmode == IEEE80211_M_STA &&
639 vap->iv_state == IEEE80211_S_RUN) {
640 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
641 /* Enable station power save mode */
642 vap->iv_sta_ps(vap, 1);
643 /* Wait until null data frame will be ACK'ed */
644 mtx_sleep(vap, IEEE80211_LOCK_OBJ(ic), PCATCH,
645 "sta_ps", msecs_to_ticks(10));
646 if (ss_priv->ss_iflags & ISCAN_ABORT) {
647 scan_done(ss, 0);
648 return;
649 }
650 }
651 }
652
653 ss_priv->ss_scanend = ticks + ss_priv->ss_duration;
654
655 /* XXX scan state can change! Re-validate scan state! */
656
657 IEEE80211_UNLOCK(ic);
658
659 ic->ic_scan_start(ic); /* notify driver */
660
661 scan_curchan_task(ss, 0);
662 }
663
664 static void
scan_curchan_task(void * arg,int pending)665 scan_curchan_task(void *arg, int pending)
666 {
667 struct ieee80211_scan_state *ss = arg;
668 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
669 struct ieee80211com *ic = ss->ss_ic;
670 struct ieee80211_channel *chan;
671 unsigned long maxdwell;
672 int scandone;
673
674 IEEE80211_LOCK(ic);
675 end:
676 scandone = (ss->ss_next >= ss->ss_last) ||
677 (ss_priv->ss_iflags & ISCAN_CANCEL) != 0;
678
679 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
680 "%s: loop start; scandone=%d\n",
681 __func__,
682 scandone);
683
684 if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
685 (ss_priv->ss_iflags & ISCAN_ABORT) ||
686 ieee80211_time_after(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) {
687 ss_priv->ss_iflags &= ~ISCAN_RUNNING;
688 scan_end(ss, scandone);
689 return;
690 } else
691 ss_priv->ss_iflags |= ISCAN_RUNNING;
692
693 chan = ss->ss_chans[ss->ss_next++];
694
695 /*
696 * Watch for truncation due to the scan end time.
697 */
698 if (ieee80211_time_after(ticks + ss->ss_maxdwell, ss_priv->ss_scanend))
699 maxdwell = ss_priv->ss_scanend - ticks;
700 else
701 maxdwell = ss->ss_maxdwell;
702
703 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
704 "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
705 __func__,
706 ieee80211_chan2ieee(ic, ic->ic_curchan),
707 ieee80211_channel_type_char(ic->ic_curchan),
708 ieee80211_chan2ieee(ic, chan),
709 ieee80211_channel_type_char(chan),
710 (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
711 (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
712 "active" : "passive",
713 ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
714
715 /*
716 * Potentially change channel and phy mode.
717 */
718 ic->ic_curchan = chan;
719 ic->ic_rt = ieee80211_get_ratetable(chan);
720 IEEE80211_UNLOCK(ic);
721 /*
722 * Perform the channel change and scan unlocked so the driver
723 * may sleep. Once set_channel returns the hardware has
724 * completed the channel change.
725 */
726 ic->ic_set_channel(ic);
727 ieee80211_radiotap_chan_change(ic);
728
729 /*
730 * Scan curchan. Drivers for "intelligent hardware"
731 * override ic_scan_curchan to tell the device to do
732 * the work. Otherwise we manage the work ourselves;
733 * sending a probe request (as needed), and arming the
734 * timeout to switch channels after maxdwell ticks.
735 *
736 * scan_curchan should only pause for the time required to
737 * prepare/initiate the hardware for the scan (if at all).
738 */
739 ic->ic_scan_curchan(ss, maxdwell);
740 IEEE80211_LOCK(ic);
741
742 /* XXX scan state can change! Re-validate scan state! */
743
744 ss_priv->ss_chanmindwell = ticks + ss->ss_mindwell;
745 /* clear mindwell lock and initial channel change flush */
746 ss_priv->ss_iflags &= ~ISCAN_REP;
747
748 if (ss_priv->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)) {
749 taskqueue_cancel_timeout(ic->ic_tq, &ss_priv->ss_scan_curchan,
750 NULL);
751 goto end;
752 }
753
754 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: waiting\n",
755 __func__);
756 IEEE80211_UNLOCK(ic);
757 }
758
759 static void
scan_end(struct ieee80211_scan_state * ss,int scandone)760 scan_end(struct ieee80211_scan_state *ss, int scandone)
761 {
762 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
763 struct ieee80211vap *vap = ss->ss_vap;
764 struct ieee80211com *ic = ss->ss_ic;
765
766 IEEE80211_LOCK_ASSERT(ic);
767
768 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: out\n", __func__);
769
770 if (ss_priv->ss_iflags & ISCAN_ABORT) {
771 scan_done(ss, scandone);
772 return;
773 }
774
775 IEEE80211_UNLOCK(ic);
776 ic->ic_scan_end(ic); /* notify driver */
777 IEEE80211_LOCK(ic);
778 /* XXX scan state can change! Re-validate scan state! */
779
780 /*
781 * Since a cancellation may have occurred during one of the
782 * driver calls (whilst unlocked), update scandone.
783 */
784 if (scandone == 0 && (ss_priv->ss_iflags & ISCAN_CANCEL) != 0) {
785 /* XXX printf? */
786 if_printf(vap->iv_ifp,
787 "%s: OOPS! scan cancelled during driver call (1)!\n",
788 __func__);
789 scandone = 1;
790 }
791
792 /*
793 * Record scan complete time. Note that we also do
794 * this when canceled so any background scan will
795 * not be restarted for a while.
796 */
797 if (scandone)
798 ic->ic_lastscan = ticks;
799 /* return to the bss channel */
800 if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
801 ic->ic_curchan != ic->ic_bsschan) {
802 ieee80211_setupcurchan(ic, ic->ic_bsschan);
803 IEEE80211_UNLOCK(ic);
804 ic->ic_set_channel(ic);
805 ieee80211_radiotap_chan_change(ic);
806 IEEE80211_LOCK(ic);
807 }
808 /* clear internal flags and any indication of a pick */
809 ss_priv->ss_iflags &= ~ISCAN_REP;
810 ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
811
812 /*
813 * If not canceled and scan completed, do post-processing.
814 * If the callback function returns 0, then it wants to
815 * continue/restart scanning. Unfortunately we needed to
816 * notify the driver to end the scan above to avoid having
817 * rx frames alter the scan candidate list.
818 */
819 if ((ss_priv->ss_iflags & ISCAN_CANCEL) == 0 &&
820 !ss->ss_ops->scan_end(ss, vap) &&
821 (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
822 ieee80211_time_before(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) {
823 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
824 "%s: done, restart "
825 "[ticks %u, dwell min %lu scanend %lu]\n",
826 __func__,
827 ticks, ss->ss_mindwell, ss_priv->ss_scanend);
828 ss->ss_next = 0; /* reset to beginning */
829 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
830 vap->iv_stats.is_scan_active++;
831 else
832 vap->iv_stats.is_scan_passive++;
833
834 ss->ss_ops->scan_restart(ss, vap); /* XXX? */
835 ieee80211_runtask(ic, &ss_priv->ss_scan_start);
836 IEEE80211_UNLOCK(ic);
837 return;
838 }
839
840 /* past here, scandone is ``true'' if not in bg mode */
841 if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
842 scandone = 1;
843
844 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
845 "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
846 __func__, scandone ? "done" : "stopped",
847 ticks, ss->ss_mindwell, ss_priv->ss_scanend);
848
849 /*
850 * Since a cancellation may have occurred during one of the
851 * driver calls (whilst unlocked), update scandone.
852 */
853 if (scandone == 0 && (ss_priv->ss_iflags & ISCAN_CANCEL) != 0) {
854 /* XXX printf? */
855 if_printf(vap->iv_ifp,
856 "%s: OOPS! scan cancelled during driver call (2)!\n",
857 __func__);
858 scandone = 1;
859 }
860
861 scan_done(ss, scandone);
862 }
863
864 static void
scan_done(struct ieee80211_scan_state * ss,int scandone)865 scan_done(struct ieee80211_scan_state *ss, int scandone)
866 {
867 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
868 struct ieee80211com *ic = ss->ss_ic;
869 struct ieee80211vap *vap = ss->ss_vap;
870
871 IEEE80211_LOCK_ASSERT(ic);
872
873 /*
874 * Clear the SCAN bit first in case frames are
875 * pending on the station power save queue. If
876 * we defer this then the dispatch of the frames
877 * may generate a request to cancel scanning.
878 */
879 ic->ic_flags &= ~IEEE80211_F_SCAN;
880
881 /*
882 * Drop out of power save mode when a scan has
883 * completed. If this scan was prematurely terminated
884 * because it is a background scan then don't notify
885 * the ap; we'll either return to scanning after we
886 * receive the beacon frame or we'll drop out of power
887 * save mode because the beacon indicates we have frames
888 * waiting for us.
889 */
890 if (scandone) {
891 /*
892 * If we're not a scan offload device, come back out of
893 * station powersave. Offload devices handle this themselves.
894 */
895 if ((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0)
896 vap->iv_sta_ps(vap, 0);
897 if (ss->ss_next >= ss->ss_last)
898 ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
899
900 ieee80211_notify_scan_done(vap);
901 }
902 ss_priv->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
903 ss_priv->ss_scanend = 0;
904 ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
905 IEEE80211_UNLOCK(ic);
906 #undef ISCAN_REP
907 }
908
909 /*
910 * Process a beacon or probe response frame.
911 */
912 static void
ieee80211_swscan_add_scan(struct ieee80211vap * vap,struct ieee80211_channel * curchan,const struct ieee80211_scanparams * sp,const struct ieee80211_frame * wh,int subtype,int rssi,int noise)913 ieee80211_swscan_add_scan(struct ieee80211vap *vap,
914 struct ieee80211_channel *curchan,
915 const struct ieee80211_scanparams *sp,
916 const struct ieee80211_frame *wh,
917 int subtype, int rssi, int noise)
918 {
919 struct ieee80211com *ic = vap->iv_ic;
920 struct ieee80211_scan_state *ss = ic->ic_scan;
921
922 /* XXX locking */
923 /*
924 * Frames received during startup are discarded to avoid
925 * using scan state setup on the initial entry to the timer
926 * callback. This can occur because the device may enable
927 * rx prior to our doing the initial channel change in the
928 * timer routine.
929 */
930 if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
931 return;
932 #ifdef IEEE80211_DEBUG
933 if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
934 ieee80211_scan_dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
935 #endif
936 if (ss->ss_ops != NULL &&
937 ss->ss_ops->scan_add(ss, curchan, sp, wh, subtype, rssi, noise)) {
938 /*
939 * If we've reached the min dwell time terminate
940 * the timer so we'll switch to the next channel.
941 */
942 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
943 ieee80211_time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
944 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
945 "%s: chan %3d%c min dwell met (%u > %lu)\n",
946 __func__,
947 ieee80211_chan2ieee(ic, ic->ic_curchan),
948 ieee80211_channel_type_char(ic->ic_curchan),
949 ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
950 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
951 /*
952 * NB: trigger at next clock tick or wait for the
953 * hardware.
954 */
955 ic->ic_scan_mindwell(ss);
956 }
957 }
958 }
959
960 static struct ieee80211_scan_methods swscan_methods = {
961 .sc_attach = ieee80211_swscan_attach,
962 .sc_detach = ieee80211_swscan_detach,
963 .sc_vattach = ieee80211_swscan_vattach,
964 .sc_vdetach = ieee80211_swscan_vdetach,
965 .sc_set_scan_duration = ieee80211_swscan_set_scan_duration,
966 .sc_start_scan = ieee80211_swscan_start_scan,
967 .sc_check_scan = ieee80211_swscan_check_scan,
968 .sc_bg_scan = ieee80211_swscan_bg_scan,
969 .sc_cancel_scan = ieee80211_swscan_cancel_scan,
970 .sc_cancel_anyscan = ieee80211_swscan_cancel_anyscan,
971 .sc_scan_next = ieee80211_swscan_scan_next,
972 .sc_scan_done = ieee80211_swscan_scan_done,
973 .sc_scan_probe_curchan = ieee80211_swscan_probe_curchan,
974 .sc_add_scan = ieee80211_swscan_add_scan
975 };
976
977 /*
978 * Default scan attach method.
979 */
980 void
ieee80211_swscan_attach(struct ieee80211com * ic)981 ieee80211_swscan_attach(struct ieee80211com *ic)
982 {
983 struct scan_state *ss;
984
985 /*
986 * Setup the default methods
987 */
988 ic->ic_scan_methods = &swscan_methods;
989
990 /* Allocate initial scan state */
991 ss = (struct scan_state *) IEEE80211_MALLOC(sizeof(struct scan_state),
992 M_80211_SCAN, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
993 if (ss == NULL) {
994 ic->ic_scan = NULL;
995 return;
996 }
997 TASK_INIT(&ss->ss_scan_start, 0, scan_start, ss);
998 TIMEOUT_TASK_INIT(ic->ic_tq, &ss->ss_scan_curchan, 0,
999 scan_curchan_task, ss);
1000
1001 ic->ic_scan = &ss->base;
1002 ss->base.ss_ic = ic;
1003
1004 ic->ic_scan_curchan = scan_curchan;
1005 ic->ic_scan_mindwell = scan_mindwell;
1006 }
1007