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 <netproto/802_11/ieee80211_var.h>
49
50 #include <netproto/802_11/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 /*
84 * Roaming-related defaults. RSSI thresholds are as returned by the
85 * driver (.5dBm). Transmit rate thresholds are IEEE rate codes (i.e
86 * .5M units) or MCS.
87 */
88 /* rssi thresholds */
89 #define ROAM_RSSI_11A_DEFAULT 14 /* 11a bss */
90 #define ROAM_RSSI_11B_DEFAULT 14 /* 11b bss */
91 #define ROAM_RSSI_11BONLY_DEFAULT 14 /* 11b-only bss */
92 /* transmit rate thresholds */
93 #define ROAM_RATE_11A_DEFAULT 2*12 /* 11a bss */
94 #define ROAM_RATE_11B_DEFAULT 2*5 /* 11b bss */
95 #define ROAM_RATE_11BONLY_DEFAULT 2*1 /* 11b-only bss */
96 #define ROAM_RATE_HALF_DEFAULT 2*6 /* half-width 11a/g bss */
97 #define ROAM_RATE_QUARTER_DEFAULT 2*3 /* quarter-width 11a/g bss */
98 #define ROAM_MCS_11N_DEFAULT (1 | IEEE80211_RATE_MCS) /* 11n bss */
99
100 static void scan_curchan(struct ieee80211_scan_state *, unsigned long);
101 static void scan_mindwell(struct ieee80211_scan_state *);
102 static void scan_signal(struct ieee80211_scan_state *, int);
103 static void scan_signal_locked(struct ieee80211_scan_state *, int);
104 static void scan_start(void *, int);
105 static void scan_curchan_task(void *, int);
106 static void scan_end(struct ieee80211_scan_state *, int);
107 static void scan_done(struct ieee80211_scan_state *, int);
108
109 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
110
111 static void
ieee80211_swscan_detach(struct ieee80211com * ic)112 ieee80211_swscan_detach(struct ieee80211com *ic)
113 {
114 struct ieee80211_scan_state *ss = ic->ic_scan;
115
116 if (ss != NULL) {
117 scan_signal(ss, ISCAN_ABORT);
118 ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_start);
119 taskqueue_drain_timeout(ic->ic_tq,
120 &SCAN_PRIVATE(ss)->ss_scan_curchan);
121 KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0,
122 ("scan still running"));
123
124 /*
125 * For now, do the ss_ops detach here rather
126 * than ieee80211_scan_detach().
127 *
128 * I'll figure out how to cleanly split things up
129 * at a later date.
130 */
131 if (ss->ss_ops != NULL) {
132 ss->ss_ops->scan_detach(ss);
133 ss->ss_ops = NULL;
134 }
135 ic->ic_scan = NULL;
136 IEEE80211_FREE(SCAN_PRIVATE(ss), M_80211_SCAN);
137 }
138 }
139
140 static void
ieee80211_swscan_vattach(struct ieee80211vap * vap)141 ieee80211_swscan_vattach(struct ieee80211vap *vap)
142 {
143 /* nothing to do for now */
144 /*
145 * TODO: all of the vap scan calls should be methods!
146 */
147
148 }
149
150 static void
ieee80211_swscan_vdetach(struct ieee80211vap * vap)151 ieee80211_swscan_vdetach(struct ieee80211vap *vap)
152 {
153 struct ieee80211com *ic = vap->iv_ic;
154 struct ieee80211_scan_state *ss = ic->ic_scan;
155
156 IEEE80211_LOCK_ASSERT(ic);
157
158 if (ss != NULL && ss->ss_vap == vap &&
159 (ic->ic_flags & IEEE80211_F_SCAN))
160 scan_signal_locked(ss, ISCAN_ABORT);
161 }
162
163 static void
ieee80211_swscan_set_scan_duration(struct ieee80211vap * vap,u_int duration)164 ieee80211_swscan_set_scan_duration(struct ieee80211vap *vap, u_int duration)
165 {
166 struct ieee80211com *ic = vap->iv_ic;
167 struct ieee80211_scan_state *ss = ic->ic_scan;
168
169 IEEE80211_LOCK_ASSERT(ic);
170
171 /* NB: flush frames rx'd before 1st channel change */
172 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
173 SCAN_PRIVATE(ss)->ss_duration = duration;
174 }
175
176 /*
177 * Start a scan unless one is already going.
178 */
179 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[])180 ieee80211_swscan_start_scan_locked(const struct ieee80211_scanner *scan,
181 struct ieee80211vap *vap, int flags, u_int duration,
182 u_int mindwell, u_int maxdwell,
183 u_int nssid, const struct ieee80211_scan_ssid ssids[])
184 {
185 struct ieee80211com *ic = vap->iv_ic;
186 struct ieee80211_scan_state *ss = ic->ic_scan;
187
188 IEEE80211_LOCK_ASSERT(ic);
189
190 if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
191 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
192 "%s: scan inhibited by pending channel change\n", __func__);
193 } else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
194 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
195 "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
196 , __func__
197 , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
198 , duration, mindwell, maxdwell
199 , ieee80211_phymode_name[vap->iv_des_mode]
200 , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
201 , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
202 , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
203 , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
204 , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
205 , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
206 );
207
208 ieee80211_scan_update_locked(vap, scan);
209 if (ss->ss_ops != NULL) {
210 if ((flags & IEEE80211_SCAN_NOSSID) == 0)
211 ieee80211_scan_copy_ssid(vap, ss, nssid, ssids);
212
213 /* NB: top 4 bits for internal use */
214 ss->ss_flags = flags & 0xfff;
215 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
216 vap->iv_stats.is_scan_active++;
217 else
218 vap->iv_stats.is_scan_passive++;
219 if (flags & IEEE80211_SCAN_FLUSH)
220 ss->ss_ops->scan_flush(ss);
221 if (flags & IEEE80211_SCAN_BGSCAN)
222 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
223
224 /* Set duration for this particular scan */
225 ieee80211_swscan_set_scan_duration(vap, duration);
226
227 ss->ss_next = 0;
228 ss->ss_mindwell = mindwell;
229 ss->ss_maxdwell = maxdwell;
230 /* NB: scan_start must be before the scan runtask */
231 ss->ss_ops->scan_start(ss, vap);
232 #ifdef IEEE80211_DEBUG
233 if (ieee80211_msg_scan(vap))
234 ieee80211_scan_dump(ss);
235 #endif /* IEEE80211_DEBUG */
236 ic->ic_flags |= IEEE80211_F_SCAN;
237
238 /* Start scan task */
239 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_start);
240 }
241 return 1;
242 } else {
243 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
244 "%s: %s scan already in progress\n", __func__,
245 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
246 }
247 return 0;
248 }
249
250
251 /*
252 * Start a scan unless one is already going.
253 *
254 * Called without the comlock held; grab the comlock as appropriate.
255 */
256 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[])257 ieee80211_swscan_start_scan(const struct ieee80211_scanner *scan,
258 struct ieee80211vap *vap, int flags,
259 u_int duration, u_int mindwell, u_int maxdwell,
260 u_int nssid, const struct ieee80211_scan_ssid ssids[])
261 {
262 struct ieee80211com *ic = vap->iv_ic;
263 int result;
264
265 IEEE80211_UNLOCK_ASSERT(ic);
266
267 IEEE80211_LOCK(ic);
268 result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration,
269 mindwell, maxdwell, nssid, ssids);
270 IEEE80211_UNLOCK(ic);
271
272 return result;
273 }
274
275 /*
276 * Check the scan cache for an ap/channel to use; if that
277 * fails then kick off a new scan.
278 *
279 * Called with the comlock held.
280 *
281 * XXX TODO: split out!
282 */
283 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[])284 ieee80211_swscan_check_scan(const struct ieee80211_scanner *scan,
285 struct ieee80211vap *vap, int flags,
286 u_int duration, u_int mindwell, u_int maxdwell,
287 u_int nssid, const struct ieee80211_scan_ssid ssids[])
288 {
289 struct ieee80211com *ic = vap->iv_ic;
290 struct ieee80211_scan_state *ss = ic->ic_scan;
291 int result;
292
293 IEEE80211_LOCK_ASSERT(ic);
294
295 if (ss->ss_ops != NULL) {
296 /* XXX verify ss_ops matches vap->iv_opmode */
297 if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
298 /*
299 * Update the ssid list and mark flags so if
300 * we call start_scan it doesn't duplicate work.
301 */
302 ieee80211_scan_copy_ssid(vap, ss, nssid, ssids);
303 flags |= IEEE80211_SCAN_NOSSID;
304 }
305 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
306 (flags & IEEE80211_SCAN_FLUSH) == 0 &&
307 ieee80211_time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
308 /*
309 * We're not currently scanning and the cache is
310 * deemed hot enough to consult. Lock out others
311 * by marking IEEE80211_F_SCAN while we decide if
312 * something is already in the scan cache we can
313 * use. Also discard any frames that might come
314 * in while temporarily marked as scanning.
315 */
316 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
317 ic->ic_flags |= IEEE80211_F_SCAN;
318
319 /* NB: need to use supplied flags in check */
320 ss->ss_flags = flags & 0xff;
321 result = ss->ss_ops->scan_end(ss, vap);
322
323 ic->ic_flags &= ~IEEE80211_F_SCAN;
324 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
325 if (result) {
326 ieee80211_notify_scan_done(vap);
327 return 1;
328 }
329 }
330 }
331 result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration,
332 mindwell, maxdwell, nssid, ssids);
333
334 return result;
335 }
336
337 /*
338 * Restart a previous scan. If the previous scan completed
339 * then we start again using the existing channel list.
340 */
341 static int
ieee80211_swscan_bg_scan(const struct ieee80211_scanner * scan,struct ieee80211vap * vap,int flags)342 ieee80211_swscan_bg_scan(const struct ieee80211_scanner *scan,
343 struct ieee80211vap *vap, int flags)
344 {
345 struct ieee80211com *ic = vap->iv_ic;
346 struct ieee80211_scan_state *ss = ic->ic_scan;
347
348 /* XXX assert unlocked? */
349 // IEEE80211_UNLOCK_ASSERT(ic);
350
351 IEEE80211_LOCK(ic);
352 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
353 u_int duration;
354 /*
355 * Go off-channel for a fixed interval that is large
356 * enough to catch most ap's but short enough that
357 * we can return on-channel before our listen interval
358 * expires.
359 */
360 duration = IEEE80211_SCAN_OFFCHANNEL;
361
362 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
363 "%s: %s scan, ticks %u duration %u\n", __func__,
364 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
365 ticks, duration);
366
367 ieee80211_scan_update_locked(vap, scan);
368 if (ss->ss_ops != NULL) {
369 ss->ss_vap = vap;
370 /*
371 * A background scan does not select a new sta; it
372 * just refreshes the scan cache. Also, indicate
373 * the scan logic should follow the beacon schedule:
374 * we go off-channel and scan for a while, then
375 * return to the bss channel to receive a beacon,
376 * then go off-channel again. All during this time
377 * we notify the ap we're in power save mode. When
378 * the scan is complete we leave power save mode.
379 * If any beacon indicates there are frames pending
380 * for us then we drop out of power save mode
381 * (and background scan) automatically by way of the
382 * usual sta power save logic.
383 */
384 ss->ss_flags |= IEEE80211_SCAN_NOPICK
385 | IEEE80211_SCAN_BGSCAN
386 | flags
387 ;
388 /* if previous scan completed, restart */
389 if (ss->ss_next >= ss->ss_last) {
390 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
391 vap->iv_stats.is_scan_active++;
392 else
393 vap->iv_stats.is_scan_passive++;
394 /*
395 * NB: beware of the scan cache being flushed;
396 * if the channel list is empty use the
397 * scan_start method to populate it.
398 */
399 ss->ss_next = 0;
400 if (ss->ss_last != 0)
401 ss->ss_ops->scan_restart(ss, vap);
402 else {
403 ss->ss_ops->scan_start(ss, vap);
404 #ifdef IEEE80211_DEBUG
405 if (ieee80211_msg_scan(vap))
406 ieee80211_scan_dump(ss);
407 #endif /* IEEE80211_DEBUG */
408 }
409 }
410 ieee80211_swscan_set_scan_duration(vap, duration);
411 ss->ss_maxdwell = duration;
412 ic->ic_flags |= IEEE80211_F_SCAN;
413 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
414 ieee80211_runtask(ic,
415 &SCAN_PRIVATE(ss)->ss_scan_start);
416 } else {
417 /* XXX msg+stat */
418 }
419 } else {
420 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
421 "%s: %s scan already in progress\n", __func__,
422 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
423 }
424 IEEE80211_UNLOCK(ic);
425
426 /* NB: racey, does it matter? */
427 return (ic->ic_flags & IEEE80211_F_SCAN);
428 }
429
430 /*
431 * Taskqueue work to cancel a scan.
432 *
433 * Note: for offload scan devices, we may want to call into the
434 * driver to try and cancel scanning, however it may not be cancelable.
435 */
436 static void
cancel_scan(struct ieee80211vap * vap,int any,const char * func)437 cancel_scan(struct ieee80211vap *vap, int any, const char *func)
438 {
439 struct ieee80211com *ic = vap->iv_ic;
440 struct ieee80211_scan_state *ss = ic->ic_scan;
441
442 IEEE80211_LOCK(ic);
443 if ((ic->ic_flags & IEEE80211_F_SCAN) &&
444 (any || ss->ss_vap == vap) &&
445 (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
446 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
447 "%s: cancel %s scan\n", func,
448 ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
449 "active" : "passive");
450
451 /* clear bg scan NOPICK */
452 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
453 /* mark cancel request and wake up the scan task */
454 scan_signal_locked(ss, ISCAN_CANCEL);
455 } else {
456 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
457 "%s: called; F_SCAN=%d, vap=%s, CANCEL=%d\n",
458 func,
459 !! (ic->ic_flags & IEEE80211_F_SCAN),
460 (ss->ss_vap == vap ? "match" : "nomatch"),
461 !! (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL));
462 }
463 IEEE80211_UNLOCK(ic);
464 }
465
466 /*
467 * Cancel any scan currently going on for the specified vap.
468 */
469 static void
ieee80211_swscan_cancel_scan(struct ieee80211vap * vap)470 ieee80211_swscan_cancel_scan(struct ieee80211vap *vap)
471 {
472 cancel_scan(vap, 0, __func__);
473 }
474
475 /*
476 * Cancel any scan currently going on.
477 */
478 static void
ieee80211_swscan_cancel_anyscan(struct ieee80211vap * vap)479 ieee80211_swscan_cancel_anyscan(struct ieee80211vap *vap)
480 {
481 /* XXX for now - just don't do this per packet. */
482 if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD)
483 return;
484
485 cancel_scan(vap, 1, __func__);
486 }
487
488 /*
489 * Manually switch to the next channel in the channel list.
490 * Provided for drivers that manage scanning themselves
491 * (e.g. for firmware-based devices).
492 */
493 static void
ieee80211_swscan_scan_next(struct ieee80211vap * vap)494 ieee80211_swscan_scan_next(struct ieee80211vap *vap)
495 {
496 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
497
498 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
499
500 /* wake up the scan task */
501 scan_signal(ss, 0);
502 }
503
504 /*
505 * Manually stop a scan that is currently running.
506 * Provided for drivers that are not able to scan single channels
507 * (e.g. for firmware-based devices).
508 */
509 static void
ieee80211_swscan_scan_done(struct ieee80211vap * vap)510 ieee80211_swscan_scan_done(struct ieee80211vap *vap)
511 {
512 struct ieee80211com *ic = vap->iv_ic;
513 struct ieee80211_scan_state *ss = ic->ic_scan;
514
515 IEEE80211_LOCK_ASSERT(ic);
516
517 scan_signal_locked(ss, 0);
518 }
519
520 /*
521 * Probe the current channel, if allowed, while scanning.
522 * If the channel is not marked passive-only then send
523 * a probe request immediately. Otherwise mark state and
524 * listen for beacons on the channel; if we receive something
525 * then we'll transmit a probe request.
526 */
527 static void
ieee80211_swscan_probe_curchan(struct ieee80211vap * vap,int force)528 ieee80211_swscan_probe_curchan(struct ieee80211vap *vap, int force)
529 {
530 struct ieee80211com *ic = vap->iv_ic;
531 struct ieee80211_scan_state *ss = ic->ic_scan;
532 struct ifnet *ifp = vap->iv_ifp;
533 int i;
534
535 /*
536 * Full-offload scan devices don't require this.
537 */
538 if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD)
539 return;
540
541 /*
542 * Send directed probe requests followed by any
543 * broadcast probe request.
544 * XXX remove dependence on ic/vap->iv_bss
545 */
546 for (i = 0; i < ss->ss_nssid; i++)
547 ieee80211_send_probereq(vap->iv_bss,
548 vap->iv_myaddr, ifp->if_broadcastaddr,
549 ifp->if_broadcastaddr,
550 ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
551 if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
552 ieee80211_send_probereq(vap->iv_bss,
553 vap->iv_myaddr, ifp->if_broadcastaddr,
554 ifp->if_broadcastaddr,
555 "", 0);
556 }
557
558 /*
559 * Scan curchan. If this is an active scan and the channel
560 * is not marked passive then send probe request frame(s).
561 * Arrange for the channel change after maxdwell ticks.
562 */
563 static void
scan_curchan(struct ieee80211_scan_state * ss,unsigned long maxdwell)564 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
565 {
566 struct ieee80211vap *vap = ss->ss_vap;
567 struct ieee80211com *ic = ss->ss_ic;
568
569 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
570 "%s: calling; maxdwell=%lu\n",
571 __func__,
572 maxdwell);
573 IEEE80211_LOCK(ic);
574 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
575 ieee80211_probe_curchan(vap, 0);
576 taskqueue_enqueue_timeout(ic->ic_tq,
577 &SCAN_PRIVATE(ss)->ss_scan_curchan, maxdwell);
578 IEEE80211_UNLOCK(ic);
579 }
580
581 static void
scan_signal(struct ieee80211_scan_state * ss,int iflags)582 scan_signal(struct ieee80211_scan_state *ss, int iflags)
583 {
584 struct ieee80211com *ic = ss->ss_ic;
585
586 IEEE80211_UNLOCK_ASSERT(ic);
587
588 IEEE80211_LOCK(ic);
589 scan_signal_locked(ss, iflags);
590 IEEE80211_UNLOCK(ic);
591 }
592
593 static void
scan_signal_locked(struct ieee80211_scan_state * ss,int iflags)594 scan_signal_locked(struct ieee80211_scan_state *ss, int iflags)
595 {
596 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
597 struct timeout_task *scan_task = &ss_priv->ss_scan_curchan;
598 struct ieee80211com *ic = ss->ss_ic;
599
600 IEEE80211_LOCK_ASSERT(ic);
601
602 ss_priv->ss_iflags |= iflags;
603 if (ss_priv->ss_iflags & ISCAN_RUNNING) {
604 if (taskqueue_cancel_timeout(ic->ic_tq, scan_task, NULL) == 0)
605 taskqueue_enqueue_timeout(ic->ic_tq, scan_task, 0);
606 }
607 }
608
609 /*
610 * Handle mindwell requirements completed; initiate a channel
611 * change to the next channel asap.
612 */
613 static void
scan_mindwell(struct ieee80211_scan_state * ss)614 scan_mindwell(struct ieee80211_scan_state *ss)
615 {
616
617 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: called\n",
618 __func__);
619
620 scan_signal(ss, 0);
621 }
622
623 static void
scan_start(void * arg,int pending)624 scan_start(void *arg, int pending)
625 {
626 #define ISCAN_REP (ISCAN_MINDWELL | ISCAN_DISCARD)
627 struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
628 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
629 struct ieee80211vap *vap = ss->ss_vap;
630 struct ieee80211com *ic = ss->ss_ic;
631
632 IEEE80211_LOCK(ic);
633 if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
634 (ss_priv->ss_iflags & ISCAN_ABORT)) {
635 /* Cancelled before we started */
636 scan_done(ss, 0);
637 return;
638 }
639
640 if (ss->ss_next == ss->ss_last) {
641 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
642 "%s: no channels to scan\n", __func__);
643 scan_done(ss, 1);
644 return;
645 }
646
647 /*
648 * Put the station into power save mode.
649 *
650 * This is only required if we're not a full-offload device;
651 * those devices manage scan/traffic differently.
652 */
653 if (((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0) &&
654 vap->iv_opmode == IEEE80211_M_STA &&
655 vap->iv_state == IEEE80211_S_RUN) {
656 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
657 /* Enable station power save mode */
658 vap->iv_sta_ps(vap, 1);
659 /* Wait until null data frame will be ACK'ed */
660 #if defined(__DragonFly__)
661 lksleep(vap, IEEE80211_LOCK_OBJ(ic), PCATCH,
662 "sta_ps", msecs_to_ticks(10));
663 #else
664 mtx_sleep(vap, IEEE80211_LOCK_OBJ(ic), PCATCH,
665 "sta_ps", msecs_to_ticks(10));
666 #endif
667 if (ss_priv->ss_iflags & ISCAN_ABORT) {
668 scan_done(ss, 0);
669 return;
670 }
671 }
672 }
673
674 ss_priv->ss_scanend = ticks + ss_priv->ss_duration;
675
676 /* XXX scan state can change! Re-validate scan state! */
677
678 IEEE80211_UNLOCK(ic);
679
680 ic->ic_scan_start(ic); /* notify driver */
681
682 scan_curchan_task(ss, 0);
683 }
684
685 static void
scan_curchan_task(void * arg,int pending)686 scan_curchan_task(void *arg, int pending)
687 {
688 struct ieee80211_scan_state *ss = arg;
689 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
690 struct ieee80211com *ic = ss->ss_ic;
691 struct ieee80211_channel *chan;
692 unsigned long maxdwell;
693 int scandone;
694
695 IEEE80211_LOCK(ic);
696 end:
697 scandone = (ss->ss_next >= ss->ss_last) ||
698 (ss_priv->ss_iflags & ISCAN_CANCEL) != 0;
699
700 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
701 "%s: loop start; scandone=%d\n",
702 __func__,
703 scandone);
704
705 if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
706 (ss_priv->ss_iflags & ISCAN_ABORT) ||
707 ieee80211_time_after(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) {
708 ss_priv->ss_iflags &= ~ISCAN_RUNNING;
709 scan_end(ss, scandone);
710 return;
711 } else
712 ss_priv->ss_iflags |= ISCAN_RUNNING;
713
714 chan = ss->ss_chans[ss->ss_next++];
715
716 /*
717 * Watch for truncation due to the scan end time.
718 */
719 if (ieee80211_time_after(ticks + ss->ss_maxdwell, ss_priv->ss_scanend))
720 maxdwell = ss_priv->ss_scanend - ticks;
721 else
722 maxdwell = ss->ss_maxdwell;
723
724 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
725 "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
726 __func__,
727 ieee80211_chan2ieee(ic, ic->ic_curchan),
728 ieee80211_channel_type_char(ic->ic_curchan),
729 ieee80211_chan2ieee(ic, chan),
730 ieee80211_channel_type_char(chan),
731 (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
732 (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
733 "active" : "passive",
734 ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
735
736 /*
737 * Potentially change channel and phy mode.
738 */
739 ic->ic_curchan = chan;
740 ic->ic_rt = ieee80211_get_ratetable(chan);
741 IEEE80211_UNLOCK(ic);
742 /*
743 * Perform the channel change and scan unlocked so the driver
744 * may sleep. Once set_channel returns the hardware has
745 * completed the channel change.
746 */
747 ic->ic_set_channel(ic);
748 ieee80211_radiotap_chan_change(ic);
749
750 /*
751 * Scan curchan. Drivers for "intelligent hardware"
752 * override ic_scan_curchan to tell the device to do
753 * the work. Otherwise we manage the work ourselves;
754 * sending a probe request (as needed), and arming the
755 * timeout to switch channels after maxdwell ticks.
756 *
757 * scan_curchan should only pause for the time required to
758 * prepare/initiate the hardware for the scan (if at all).
759 */
760 ic->ic_scan_curchan(ss, maxdwell);
761 IEEE80211_LOCK(ic);
762
763 /* XXX scan state can change! Re-validate scan state! */
764
765 ss_priv->ss_chanmindwell = ticks + ss->ss_mindwell;
766 /* clear mindwell lock and initial channel change flush */
767 ss_priv->ss_iflags &= ~ISCAN_REP;
768
769 if (ss_priv->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)) {
770 taskqueue_cancel_timeout(ic->ic_tq, &ss_priv->ss_scan_curchan,
771 NULL);
772 goto end;
773 }
774
775 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: waiting\n",
776 __func__);
777 IEEE80211_UNLOCK(ic);
778 }
779
780 static void
scan_end(struct ieee80211_scan_state * ss,int scandone)781 scan_end(struct ieee80211_scan_state *ss, int scandone)
782 {
783 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
784 struct ieee80211vap *vap = ss->ss_vap;
785 struct ieee80211com *ic = ss->ss_ic;
786
787 IEEE80211_LOCK_ASSERT(ic);
788
789 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: out\n", __func__);
790
791 if (ss_priv->ss_iflags & ISCAN_ABORT) {
792 scan_done(ss, scandone);
793 return;
794 }
795
796 IEEE80211_UNLOCK(ic);
797 ic->ic_scan_end(ic); /* notify driver */
798 IEEE80211_LOCK(ic);
799 /* XXX scan state can change! Re-validate scan state! */
800
801 /*
802 * Since a cancellation may have occurred during one of the
803 * driver calls (whilst unlocked), update scandone.
804 */
805 if (scandone == 0 && (ss_priv->ss_iflags & ISCAN_CANCEL) != 0) {
806 /* XXX printf? */
807 if_printf(vap->iv_ifp,
808 "%s: OOPS! scan cancelled during driver call (1)!\n",
809 __func__);
810 scandone = 1;
811 }
812
813 /*
814 * Record scan complete time. Note that we also do
815 * this when canceled so any background scan will
816 * not be restarted for a while.
817 */
818 if (scandone)
819 ic->ic_lastscan = ticks;
820 /* return to the bss channel */
821 if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
822 ic->ic_curchan != ic->ic_bsschan) {
823 ieee80211_setupcurchan(ic, ic->ic_bsschan);
824 IEEE80211_UNLOCK(ic);
825 ic->ic_set_channel(ic);
826 ieee80211_radiotap_chan_change(ic);
827 IEEE80211_LOCK(ic);
828 }
829 /* clear internal flags and any indication of a pick */
830 ss_priv->ss_iflags &= ~ISCAN_REP;
831 ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
832
833 /*
834 * If not canceled and scan completed, do post-processing.
835 * If the callback function returns 0, then it wants to
836 * continue/restart scanning. Unfortunately we needed to
837 * notify the driver to end the scan above to avoid having
838 * rx frames alter the scan candidate list.
839 */
840 if ((ss_priv->ss_iflags & ISCAN_CANCEL) == 0 &&
841 !ss->ss_ops->scan_end(ss, vap) &&
842 (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
843 ieee80211_time_before(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) {
844 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
845 "%s: done, restart "
846 "[ticks %u, dwell min %lu scanend %lu]\n",
847 __func__,
848 ticks, ss->ss_mindwell, ss_priv->ss_scanend);
849 ss->ss_next = 0; /* reset to beginning */
850 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
851 vap->iv_stats.is_scan_active++;
852 else
853 vap->iv_stats.is_scan_passive++;
854
855 ss->ss_ops->scan_restart(ss, vap); /* XXX? */
856 ieee80211_runtask(ic, &ss_priv->ss_scan_start);
857 IEEE80211_UNLOCK(ic);
858 return;
859 }
860
861 /* past here, scandone is ``true'' if not in bg mode */
862 if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
863 scandone = 1;
864
865 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
866 "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
867 __func__, scandone ? "done" : "stopped",
868 ticks, ss->ss_mindwell, ss_priv->ss_scanend);
869
870 /*
871 * Since a cancellation may have occurred during one of the
872 * driver calls (whilst unlocked), update scandone.
873 */
874 if (scandone == 0 && (ss_priv->ss_iflags & ISCAN_CANCEL) != 0) {
875 /* XXX printf? */
876 if_printf(vap->iv_ifp,
877 "%s: OOPS! scan cancelled during driver call (2)!\n",
878 __func__);
879 scandone = 1;
880 }
881
882 scan_done(ss, scandone);
883 }
884
885 static void
scan_done(struct ieee80211_scan_state * ss,int scandone)886 scan_done(struct ieee80211_scan_state *ss, int scandone)
887 {
888 struct scan_state *ss_priv = SCAN_PRIVATE(ss);
889 struct ieee80211com *ic = ss->ss_ic;
890 struct ieee80211vap *vap = ss->ss_vap;
891
892 IEEE80211_LOCK_ASSERT(ic);
893
894 /*
895 * Clear the SCAN bit first in case frames are
896 * pending on the station power save queue. If
897 * we defer this then the dispatch of the frames
898 * may generate a request to cancel scanning.
899 */
900 ic->ic_flags &= ~IEEE80211_F_SCAN;
901
902 /*
903 * Drop out of power save mode when a scan has
904 * completed. If this scan was prematurely terminated
905 * because it is a background scan then don't notify
906 * the ap; we'll either return to scanning after we
907 * receive the beacon frame or we'll drop out of power
908 * save mode because the beacon indicates we have frames
909 * waiting for us.
910 */
911 if (scandone) {
912 /*
913 * If we're not a scan offload device, come back out of
914 * station powersave. Offload devices handle this themselves.
915 */
916 if ((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0)
917 vap->iv_sta_ps(vap, 0);
918 if (ss->ss_next >= ss->ss_last)
919 ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
920 ieee80211_notify_scan_done(vap);
921 }
922 ss_priv->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
923 ss_priv->ss_scanend = 0;
924 ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
925 IEEE80211_UNLOCK(ic);
926 #undef ISCAN_REP
927 }
928
929 /*
930 * Process a beacon or probe response frame.
931 */
932 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)933 ieee80211_swscan_add_scan(struct ieee80211vap *vap,
934 struct ieee80211_channel *curchan,
935 const struct ieee80211_scanparams *sp,
936 const struct ieee80211_frame *wh,
937 int subtype, int rssi, int noise)
938 {
939 struct ieee80211com *ic = vap->iv_ic;
940 struct ieee80211_scan_state *ss = ic->ic_scan;
941
942 /* XXX locking */
943 /*
944 * Frames received during startup are discarded to avoid
945 * using scan state setup on the initial entry to the timer
946 * callback. This can occur because the device may enable
947 * rx prior to our doing the initial channel change in the
948 * timer routine.
949 */
950 if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
951 return;
952 #ifdef IEEE80211_DEBUG
953 if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
954 ieee80211_scan_dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
955 #endif
956 if (ss->ss_ops != NULL &&
957 ss->ss_ops->scan_add(ss, curchan, sp, wh, subtype, rssi, noise)) {
958 /*
959 * If we've reached the min dwell time terminate
960 * the timer so we'll switch to the next channel.
961 */
962 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
963 ieee80211_time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
964 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
965 "%s: chan %3d%c min dwell met (%u > %lu)\n",
966 __func__,
967 ieee80211_chan2ieee(ic, ic->ic_curchan),
968 ieee80211_channel_type_char(ic->ic_curchan),
969 ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
970 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
971 /*
972 * NB: trigger at next clock tick or wait for the
973 * hardware.
974 */
975 ic->ic_scan_mindwell(ss);
976 }
977 }
978 }
979
980 static struct ieee80211_scan_methods swscan_methods = {
981 .sc_attach = ieee80211_swscan_attach,
982 .sc_detach = ieee80211_swscan_detach,
983 .sc_vattach = ieee80211_swscan_vattach,
984 .sc_vdetach = ieee80211_swscan_vdetach,
985 .sc_set_scan_duration = ieee80211_swscan_set_scan_duration,
986 .sc_start_scan = ieee80211_swscan_start_scan,
987 .sc_check_scan = ieee80211_swscan_check_scan,
988 .sc_bg_scan = ieee80211_swscan_bg_scan,
989 .sc_cancel_scan = ieee80211_swscan_cancel_scan,
990 .sc_cancel_anyscan = ieee80211_swscan_cancel_anyscan,
991 .sc_scan_next = ieee80211_swscan_scan_next,
992 .sc_scan_done = ieee80211_swscan_scan_done,
993 .sc_scan_probe_curchan = ieee80211_swscan_probe_curchan,
994 .sc_add_scan = ieee80211_swscan_add_scan
995 };
996
997 /*
998 * Default scan attach method.
999 */
1000 void
ieee80211_swscan_attach(struct ieee80211com * ic)1001 ieee80211_swscan_attach(struct ieee80211com *ic)
1002 {
1003 struct scan_state *ss;
1004
1005 /*
1006 * Setup the default methods
1007 */
1008 ic->ic_scan_methods = &swscan_methods;
1009
1010 /* Allocate initial scan state */
1011 #if defined(__DragonFly__)
1012 ss = (struct scan_state *) kmalloc(sizeof(struct scan_state),
1013 M_80211_SCAN, M_INTWAIT | M_ZERO);
1014 #else
1015 ss = (struct scan_state *) IEEE80211_MALLOC(sizeof(struct scan_state),
1016 M_80211_SCAN, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
1017 #endif
1018 if (ss == NULL) {
1019 ic->ic_scan = NULL;
1020 return;
1021 }
1022 TASK_INIT(&ss->ss_scan_start, 0, scan_start, ss);
1023 TIMEOUT_TASK_INIT(ic->ic_tq, &ss->ss_scan_curchan, 0,
1024 scan_curchan_task, ss);
1025
1026 ic->ic_scan = &ss->base;
1027 ss->base.ss_ic = ic;
1028
1029 ic->ic_scan_curchan = scan_curchan;
1030 ic->ic_scan_mindwell = scan_mindwell;
1031 }
1032