xref: /freebsd/sys/net80211/ieee80211_scan.c (revision 830940567b49bb0c08dfaed40418999e76616909)
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/condvar.h>
39 
40 #include <sys/socket.h>
41 
42 #include <net/if.h>
43 #include <net/if_media.h>
44 #include <net/ethernet.h>
45 
46 #include <net80211/ieee80211_var.h>
47 
48 #include <net/bpf.h>
49 
50 struct scan_state {
51 	struct ieee80211_scan_state base;	/* public state */
52 
53 	u_int		ss_iflags;		/* flags used internally */
54 #define	ISCAN_MINDWELL 	0x0001		/* min dwell time reached */
55 #define	ISCAN_DISCARD	0x0002		/* discard rx'd frames */
56 #define	ISCAN_CANCEL	0x0004		/* cancel current scan */
57 #define	ISCAN_ABORT	0x0008		/* end the scan immediately */
58 	unsigned long	ss_chanmindwell;	/* min dwell on curchan */
59 	unsigned long	ss_scanend;		/* time scan must stop */
60 	u_int		ss_duration;		/* duration for next scan */
61 	struct task	ss_scan_task;		/* scan execution */
62 	struct cv	ss_scan_cv;		/* scan signal */
63 	struct callout	ss_scan_timer;		/* scan timer */
64 };
65 #define	SCAN_PRIVATE(ss)	((struct scan_state *) ss)
66 
67 /*
68  * Amount of time to go off-channel during a background
69  * scan.  This value should be large enough to catch most
70  * ap's but short enough that we can return on-channel
71  * before our listen interval expires.
72  *
73  * XXX tunable
74  * XXX check against configured listen interval
75  */
76 #define	IEEE80211_SCAN_OFFCHANNEL	msecs_to_ticks(150)
77 
78 /*
79  * Roaming-related defaults.  RSSI thresholds are as returned by the
80  * driver (.5dBm).  Transmit rate thresholds are IEEE rate codes (i.e
81  * .5M units) or MCS.
82  */
83 /* rssi thresholds */
84 #define	ROAM_RSSI_11A_DEFAULT		14	/* 11a bss */
85 #define	ROAM_RSSI_11B_DEFAULT		14	/* 11b bss */
86 #define	ROAM_RSSI_11BONLY_DEFAULT	14	/* 11b-only bss */
87 /* transmit rate thresholds */
88 #define	ROAM_RATE_11A_DEFAULT		2*12	/* 11a bss */
89 #define	ROAM_RATE_11B_DEFAULT		2*5	/* 11b bss */
90 #define	ROAM_RATE_11BONLY_DEFAULT	2*1	/* 11b-only bss */
91 #define	ROAM_RATE_HALF_DEFAULT		2*6	/* half-width 11a/g bss */
92 #define	ROAM_RATE_QUARTER_DEFAULT	2*3	/* quarter-width 11a/g bss */
93 #define	ROAM_MCS_11N_DEFAULT		(1 | IEEE80211_RATE_MCS) /* 11n bss */
94 
95 static	void scan_curchan(struct ieee80211_scan_state *, unsigned long);
96 static	void scan_mindwell(struct ieee80211_scan_state *);
97 static	void scan_signal(void *);
98 static	void scan_task(void *, int);
99 
100 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
101 
102 void
103 ieee80211_scan_attach(struct ieee80211com *ic)
104 {
105 	struct scan_state *ss;
106 
107 	ss = (struct scan_state *) malloc(sizeof(struct scan_state),
108 		M_80211_SCAN, M_NOWAIT | M_ZERO);
109 	if (ss == NULL) {
110 		ic->ic_scan = NULL;
111 		return;
112 	}
113 	callout_init_mtx(&ss->ss_scan_timer, IEEE80211_LOCK_OBJ(ic), 0);
114 	cv_init(&ss->ss_scan_cv, "scan");
115 	TASK_INIT(&ss->ss_scan_task, 0, scan_task, ss);
116 	ic->ic_scan = &ss->base;
117 	ss->base.ss_ic = ic;
118 
119 	ic->ic_scan_curchan = scan_curchan;
120 	ic->ic_scan_mindwell = scan_mindwell;
121 }
122 
123 void
124 ieee80211_scan_detach(struct ieee80211com *ic)
125 {
126 	struct ieee80211_scan_state *ss = ic->ic_scan;
127 
128 	if (ss != NULL) {
129 		IEEE80211_LOCK(ic);
130 		SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
131 		scan_signal(ss);
132 		IEEE80211_UNLOCK(ic);
133 		ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
134 		callout_drain(&SCAN_PRIVATE(ss)->ss_scan_timer);
135 		KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0,
136 		    ("scan still running"));
137 		if (ss->ss_ops != NULL) {
138 			ss->ss_ops->scan_detach(ss);
139 			ss->ss_ops = NULL;
140 		}
141 		ic->ic_scan = NULL;
142 		free(SCAN_PRIVATE(ss), M_80211_SCAN);
143 	}
144 }
145 
146 static const struct ieee80211_roamparam defroam[IEEE80211_MODE_MAX] = {
147 	[IEEE80211_MODE_11A]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
148 				    .rate = ROAM_RATE_11A_DEFAULT },
149 	[IEEE80211_MODE_11G]	= { .rssi = ROAM_RSSI_11B_DEFAULT,
150 				    .rate = ROAM_RATE_11B_DEFAULT },
151 	[IEEE80211_MODE_11B]	= { .rssi = ROAM_RSSI_11BONLY_DEFAULT,
152 				    .rate = ROAM_RATE_11BONLY_DEFAULT },
153 	[IEEE80211_MODE_TURBO_A]= { .rssi = ROAM_RSSI_11A_DEFAULT,
154 				    .rate = ROAM_RATE_11A_DEFAULT },
155 	[IEEE80211_MODE_TURBO_G]= { .rssi = ROAM_RSSI_11A_DEFAULT,
156 				    .rate = ROAM_RATE_11A_DEFAULT },
157 	[IEEE80211_MODE_STURBO_A]={ .rssi = ROAM_RSSI_11A_DEFAULT,
158 				    .rate = ROAM_RATE_11A_DEFAULT },
159 	[IEEE80211_MODE_HALF]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
160 				    .rate = ROAM_RATE_HALF_DEFAULT },
161 	[IEEE80211_MODE_QUARTER]= { .rssi = ROAM_RSSI_11A_DEFAULT,
162 				    .rate = ROAM_RATE_QUARTER_DEFAULT },
163 	[IEEE80211_MODE_11NA]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
164 				    .rate = ROAM_MCS_11N_DEFAULT },
165 	[IEEE80211_MODE_11NG]	= { .rssi = ROAM_RSSI_11B_DEFAULT,
166 				    .rate = ROAM_MCS_11N_DEFAULT },
167 };
168 
169 void
170 ieee80211_scan_vattach(struct ieee80211vap *vap)
171 {
172 	vap->iv_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz;
173 	vap->iv_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz;
174 	vap->iv_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz;
175 
176 	vap->iv_roaming = IEEE80211_ROAMING_AUTO;
177 	memcpy(vap->iv_roamparms, defroam, sizeof(defroam));
178 }
179 
180 void
181 ieee80211_scan_vdetach(struct ieee80211vap *vap)
182 {
183 	struct ieee80211com *ic = vap->iv_ic;
184 	struct ieee80211_scan_state *ss;
185 
186 	IEEE80211_LOCK(ic);
187 	ss = ic->ic_scan;
188 	if (ss != NULL && ss->ss_vap == vap) {
189 		if (ic->ic_flags & IEEE80211_F_SCAN) {
190 			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
191 			scan_signal(ss);
192 		}
193 		if (ss->ss_ops != NULL) {
194 			ss->ss_ops->scan_detach(ss);
195 			ss->ss_ops = NULL;
196 		}
197 		ss->ss_vap = NULL;
198 	}
199 	IEEE80211_UNLOCK(ic);
200 }
201 
202 /*
203  * Simple-minded scanner module support.
204  */
205 static const char *scan_modnames[IEEE80211_OPMODE_MAX] = {
206 	"wlan_scan_sta",	/* IEEE80211_M_IBSS */
207 	"wlan_scan_sta",	/* IEEE80211_M_STA */
208 	"wlan_scan_wds",	/* IEEE80211_M_WDS */
209 	"wlan_scan_sta",	/* IEEE80211_M_AHDEMO */
210 	"wlan_scan_ap",		/* IEEE80211_M_HOSTAP */
211 	"wlan_scan_monitor",	/* IEEE80211_M_MONITOR */
212 	"wlan_scan_sta",	/* IEEE80211_M_MBSS */
213 };
214 static const struct ieee80211_scanner *scanners[IEEE80211_OPMODE_MAX];
215 
216 const struct ieee80211_scanner *
217 ieee80211_scanner_get(enum ieee80211_opmode mode)
218 {
219 	if (mode >= IEEE80211_OPMODE_MAX)
220 		return NULL;
221 	if (scanners[mode] == NULL)
222 		ieee80211_load_module(scan_modnames[mode]);
223 	return scanners[mode];
224 }
225 
226 void
227 ieee80211_scanner_register(enum ieee80211_opmode mode,
228 	const struct ieee80211_scanner *scan)
229 {
230 	if (mode >= IEEE80211_OPMODE_MAX)
231 		return;
232 	scanners[mode] = scan;
233 }
234 
235 void
236 ieee80211_scanner_unregister(enum ieee80211_opmode mode,
237 	const struct ieee80211_scanner *scan)
238 {
239 	if (mode >= IEEE80211_OPMODE_MAX)
240 		return;
241 	if (scanners[mode] == scan)
242 		scanners[mode] = NULL;
243 }
244 
245 void
246 ieee80211_scanner_unregister_all(const struct ieee80211_scanner *scan)
247 {
248 	int m;
249 
250 	for (m = 0; m < IEEE80211_OPMODE_MAX; m++)
251 		if (scanners[m] == scan)
252 			scanners[m] = NULL;
253 }
254 
255 /*
256  * Update common scanner state to reflect the current
257  * operating mode.  This is called when the state machine
258  * is transitioned to RUN state w/o scanning--e.g. when
259  * operating in monitor mode.  The purpose of this is to
260  * ensure later callbacks find ss_ops set to properly
261  * reflect current operating mode.
262  */
263 static void
264 scan_update_locked(struct ieee80211vap *vap,
265 	const struct ieee80211_scanner *scan)
266 {
267 	struct ieee80211com *ic = vap->iv_ic;
268 	struct ieee80211_scan_state *ss = ic->ic_scan;
269 
270 	IEEE80211_LOCK_ASSERT(ic);
271 
272 #ifdef IEEE80211_DEBUG
273 	if (ss->ss_vap != vap || ss->ss_ops != scan) {
274 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
275 		    "%s: current scanner is <%s:%s>, switch to <%s:%s>\n",
276 		    __func__,
277 		    ss->ss_vap != NULL ?
278 			ss->ss_vap->iv_ifp->if_xname : "none",
279 		    ss->ss_vap != NULL ?
280 			ieee80211_opmode_name[ss->ss_vap->iv_opmode] : "none",
281 		    vap->iv_ifp->if_xname,
282 		    ieee80211_opmode_name[vap->iv_opmode]);
283 	}
284 #endif
285 	ss->ss_vap = vap;
286 	if (ss->ss_ops != scan) {
287 		/*
288 		 * Switch scanners; detach old, attach new.  Special
289 		 * case where a single scan module implements multiple
290 		 * policies by using different scan ops but a common
291 		 * core.  We assume if the old and new attach methods
292 		 * are identical then it's ok to just change ss_ops
293 		 * and not flush the internal state of the module.
294 		 */
295 		if (scan == NULL || ss->ss_ops == NULL ||
296 		    ss->ss_ops->scan_attach != scan->scan_attach) {
297 			if (ss->ss_ops != NULL)
298 				ss->ss_ops->scan_detach(ss);
299 			if (scan != NULL && !scan->scan_attach(ss)) {
300 				/* XXX attach failure */
301 				/* XXX stat+msg */
302 				scan = NULL;
303 			}
304 		}
305 		ss->ss_ops = scan;
306 	}
307 }
308 
309 static char
310 channel_type(const struct ieee80211_channel *c)
311 {
312 	if (IEEE80211_IS_CHAN_ST(c))
313 		return 'S';
314 	if (IEEE80211_IS_CHAN_108A(c))
315 		return 'T';
316 	if (IEEE80211_IS_CHAN_108G(c))
317 		return 'G';
318 	if (IEEE80211_IS_CHAN_HT(c))
319 		return 'n';
320 	if (IEEE80211_IS_CHAN_A(c))
321 		return 'a';
322 	if (IEEE80211_IS_CHAN_ANYG(c))
323 		return 'g';
324 	if (IEEE80211_IS_CHAN_B(c))
325 		return 'b';
326 	return 'f';
327 }
328 
329 void
330 ieee80211_scan_dump_channels(const struct ieee80211_scan_state *ss)
331 {
332 	struct ieee80211com *ic = ss->ss_ic;
333 	const char *sep;
334 	int i;
335 
336 	sep = "";
337 	for (i = ss->ss_next; i < ss->ss_last; i++) {
338 		const struct ieee80211_channel *c = ss->ss_chans[i];
339 
340 		printf("%s%u%c", sep, ieee80211_chan2ieee(ic, c),
341 			channel_type(c));
342 		sep = ", ";
343 	}
344 }
345 
346 #ifdef IEEE80211_DEBUG
347 static void
348 scan_dump(struct ieee80211_scan_state *ss)
349 {
350 	struct ieee80211vap *vap = ss->ss_vap;
351 
352 	if_printf(vap->iv_ifp, "scan set ");
353 	ieee80211_scan_dump_channels(ss);
354 	printf(" dwell min %lums max %lums\n",
355 	    ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(ss->ss_maxdwell));
356 }
357 #endif /* IEEE80211_DEBUG */
358 
359 static void
360 copy_ssid(struct ieee80211vap *vap, struct ieee80211_scan_state *ss,
361 	int nssid, const struct ieee80211_scan_ssid ssids[])
362 {
363 	if (nssid > IEEE80211_SCAN_MAX_SSID) {
364 		/* XXX printf */
365 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
366 		    "%s: too many ssid %d, ignoring all of them\n",
367 		    __func__, nssid);
368 		return;
369 	}
370 	memcpy(ss->ss_ssid, ssids, nssid * sizeof(ssids[0]));
371 	ss->ss_nssid = nssid;
372 }
373 
374 /*
375  * Start a scan unless one is already going.
376  */
377 static int
378 start_scan_locked(const struct ieee80211_scanner *scan,
379 	struct ieee80211vap *vap, int flags, u_int duration,
380 	u_int mindwell, u_int maxdwell,
381 	u_int nssid, const struct ieee80211_scan_ssid ssids[])
382 {
383 	struct ieee80211com *ic = vap->iv_ic;
384 	struct ieee80211_scan_state *ss = ic->ic_scan;
385 
386 	IEEE80211_LOCK_ASSERT(ic);
387 
388 	if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
389 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
390 		    "%s: scan inhibited by pending channel change\n", __func__);
391 	} else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
392 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
393 		    "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
394 		    , __func__
395 		    , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
396 		    , duration, mindwell, maxdwell
397 		    , ieee80211_phymode_name[vap->iv_des_mode]
398 		    , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
399 		    , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
400 		    , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
401 		    , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
402 		    , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
403 		    , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
404 		);
405 
406 		scan_update_locked(vap, scan);
407 		if (ss->ss_ops != NULL) {
408 			if ((flags & IEEE80211_SCAN_NOSSID) == 0)
409 				copy_ssid(vap, ss, nssid, ssids);
410 
411 			/* NB: top 4 bits for internal use */
412 			ss->ss_flags = flags & 0xfff;
413 			if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
414 				vap->iv_stats.is_scan_active++;
415 			else
416 				vap->iv_stats.is_scan_passive++;
417 			if (flags & IEEE80211_SCAN_FLUSH)
418 				ss->ss_ops->scan_flush(ss);
419 
420 			/* NB: flush frames rx'd before 1st channel change */
421 			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
422 			SCAN_PRIVATE(ss)->ss_duration = duration;
423 			ss->ss_next = 0;
424 			ss->ss_mindwell = mindwell;
425 			ss->ss_maxdwell = maxdwell;
426 			/* NB: scan_start must be before the scan runtask */
427 			ss->ss_ops->scan_start(ss, vap);
428 #ifdef IEEE80211_DEBUG
429 			if (ieee80211_msg_scan(vap))
430 				scan_dump(ss);
431 #endif /* IEEE80211_DEBUG */
432 			ic->ic_flags |= IEEE80211_F_SCAN;
433 			ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
434 		}
435 	} else {
436 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
437 		    "%s: %s scan already in progress\n", __func__,
438 		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
439 	}
440 	return (ic->ic_flags & IEEE80211_F_SCAN);
441 }
442 
443 /*
444  * Start a scan unless one is already going.
445  */
446 int
447 ieee80211_start_scan(struct ieee80211vap *vap, int flags,
448 	u_int duration, u_int mindwell, u_int maxdwell,
449 	u_int nssid, const struct ieee80211_scan_ssid ssids[])
450 {
451 	struct ieee80211com *ic = vap->iv_ic;
452 	const struct ieee80211_scanner *scan;
453 	int result;
454 
455 	scan = ieee80211_scanner_get(vap->iv_opmode);
456 	if (scan == NULL) {
457 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
458 		    "%s: no scanner support for %s mode\n",
459 		    __func__, ieee80211_opmode_name[vap->iv_opmode]);
460 		/* XXX stat */
461 		return 0;
462 	}
463 
464 	IEEE80211_LOCK(ic);
465 	result = start_scan_locked(scan, vap, flags, duration,
466 	    mindwell, maxdwell, nssid, ssids);
467 	IEEE80211_UNLOCK(ic);
468 
469 	return result;
470 }
471 
472 /*
473  * Check the scan cache for an ap/channel to use; if that
474  * fails then kick off a new scan.
475  */
476 int
477 ieee80211_check_scan(struct ieee80211vap *vap, int flags,
478 	u_int duration, u_int mindwell, u_int maxdwell,
479 	u_int nssid, const struct ieee80211_scan_ssid ssids[])
480 {
481 	struct ieee80211com *ic = vap->iv_ic;
482 	struct ieee80211_scan_state *ss = ic->ic_scan;
483 	const struct ieee80211_scanner *scan;
484 	int result;
485 
486 	scan = ieee80211_scanner_get(vap->iv_opmode);
487 	if (scan == NULL) {
488 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
489 		    "%s: no scanner support for %s mode\n",
490 		    __func__, vap->iv_opmode);
491 		/* XXX stat */
492 		return 0;
493 	}
494 
495 	/*
496 	 * Check if there's a list of scan candidates already.
497 	 * XXX want more than the ap we're currently associated with
498 	 */
499 
500 	IEEE80211_LOCK(ic);
501 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
502 	    "%s: %s scan, %s%s%s%s%s\n"
503 	    , __func__
504 	    , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
505 	    , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
506 	    , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
507 	    , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
508 	    , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
509 	    , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
510 	);
511 
512 	if (ss->ss_ops != scan) {
513 		/* XXX re-use cache contents? e.g. adhoc<->sta */
514 		flags |= IEEE80211_SCAN_FLUSH;
515 	}
516 	scan_update_locked(vap, scan);
517 	if (ss->ss_ops != NULL) {
518 		/* XXX verify ss_ops matches vap->iv_opmode */
519 		if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
520 			/*
521 			 * Update the ssid list and mark flags so if
522 			 * we call start_scan it doesn't duplicate work.
523 			 */
524 			copy_ssid(vap, ss, nssid, ssids);
525 			flags |= IEEE80211_SCAN_NOSSID;
526 		}
527 		if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
528 		    (flags & IEEE80211_SCAN_FLUSH) == 0 &&
529 		    time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
530 			/*
531 			 * We're not currently scanning and the cache is
532 			 * deemed hot enough to consult.  Lock out others
533 			 * by marking IEEE80211_F_SCAN while we decide if
534 			 * something is already in the scan cache we can
535 			 * use.  Also discard any frames that might come
536 			 * in while temporarily marked as scanning.
537 			 */
538 			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
539 			ic->ic_flags |= IEEE80211_F_SCAN;
540 
541 			/* NB: need to use supplied flags in check */
542 			ss->ss_flags = flags & 0xff;
543 			result = ss->ss_ops->scan_end(ss, vap);
544 
545 			ic->ic_flags &= ~IEEE80211_F_SCAN;
546 			SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
547 			if (result) {
548 				ieee80211_notify_scan_done(vap);
549 				IEEE80211_UNLOCK(ic);
550 				return 1;
551 			}
552 		}
553 	}
554 	result = start_scan_locked(scan, vap, flags, duration,
555 	    mindwell, maxdwell, nssid, ssids);
556 	IEEE80211_UNLOCK(ic);
557 
558 	return result;
559 }
560 
561 /*
562  * Check the scan cache for an ap/channel to use; if that fails
563  * then kick off a scan using the current settings.
564  */
565 int
566 ieee80211_check_scan_current(struct ieee80211vap *vap)
567 {
568 	return ieee80211_check_scan(vap,
569 	    IEEE80211_SCAN_ACTIVE,
570 	    IEEE80211_SCAN_FOREVER, 0, 0,
571 	    vap->iv_des_nssid, vap->iv_des_ssid);
572 }
573 
574 /*
575  * Restart a previous scan.  If the previous scan completed
576  * then we start again using the existing channel list.
577  */
578 int
579 ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
580 {
581 	struct ieee80211com *ic = vap->iv_ic;
582 	struct ieee80211_scan_state *ss = ic->ic_scan;
583 	const struct ieee80211_scanner *scan;
584 
585 	scan = ieee80211_scanner_get(vap->iv_opmode);
586 	if (scan == NULL) {
587 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
588 		    "%s: no scanner support for %s mode\n",
589 		    __func__, vap->iv_opmode);
590 		/* XXX stat */
591 		return 0;
592 	}
593 
594 	IEEE80211_LOCK(ic);
595 	if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
596 		u_int duration;
597 		/*
598 		 * Go off-channel for a fixed interval that is large
599 		 * enough to catch most ap's but short enough that
600 		 * we can return on-channel before our listen interval
601 		 * expires.
602 		 */
603 		duration = IEEE80211_SCAN_OFFCHANNEL;
604 
605 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
606 		    "%s: %s scan, ticks %u duration %lu\n", __func__,
607 		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
608 		    ticks, duration);
609 
610 		scan_update_locked(vap, scan);
611 		if (ss->ss_ops != NULL) {
612 			ss->ss_vap = vap;
613 			/*
614 			 * A background scan does not select a new sta; it
615 			 * just refreshes the scan cache.  Also, indicate
616 			 * the scan logic should follow the beacon schedule:
617 			 * we go off-channel and scan for a while, then
618 			 * return to the bss channel to receive a beacon,
619 			 * then go off-channel again.  All during this time
620 			 * we notify the ap we're in power save mode.  When
621 			 * the scan is complete we leave power save mode.
622 			 * If any beacon indicates there are frames pending
623 			 * for us then we drop out of power save mode
624 			 * (and background scan) automatically by way of the
625 			 * usual sta power save logic.
626 			 */
627 			ss->ss_flags |= IEEE80211_SCAN_NOPICK
628 				     |  IEEE80211_SCAN_BGSCAN
629 				     |  flags
630 				     ;
631 			/* if previous scan completed, restart */
632 			if (ss->ss_next >= ss->ss_last) {
633 				if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
634 					vap->iv_stats.is_scan_active++;
635 				else
636 					vap->iv_stats.is_scan_passive++;
637 				/*
638 				 * NB: beware of the scan cache being flushed;
639 				 *     if the channel list is empty use the
640 				 *     scan_start method to populate it.
641 				 */
642 				ss->ss_next = 0;
643 				if (ss->ss_last != 0)
644 					ss->ss_ops->scan_restart(ss, vap);
645 				else {
646 					ss->ss_ops->scan_start(ss, vap);
647 #ifdef IEEE80211_DEBUG
648 					if (ieee80211_msg_scan(vap))
649 						scan_dump(ss);
650 #endif /* IEEE80211_DEBUG */
651 				}
652 			}
653 			/* NB: flush frames rx'd before 1st channel change */
654 			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
655 			SCAN_PRIVATE(ss)->ss_duration = duration;
656 			ss->ss_maxdwell = duration;
657 			ic->ic_flags |= IEEE80211_F_SCAN;
658 			ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
659 			ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
660 		} else {
661 			/* XXX msg+stat */
662 		}
663 	} else {
664 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
665 		    "%s: %s scan already in progress\n", __func__,
666 		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
667 	}
668 	IEEE80211_UNLOCK(ic);
669 
670 	/* NB: racey, does it matter? */
671 	return (ic->ic_flags & IEEE80211_F_SCAN);
672 }
673 
674 /*
675  * Cancel any scan currently going on for the specified vap.
676  */
677 void
678 ieee80211_cancel_scan(struct ieee80211vap *vap)
679 {
680 	struct ieee80211com *ic = vap->iv_ic;
681 	struct ieee80211_scan_state *ss = ic->ic_scan;
682 
683 	IEEE80211_LOCK(ic);
684 	if ((ic->ic_flags & IEEE80211_F_SCAN) &&
685 	    ss->ss_vap == vap &&
686 	    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
687 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
688 		    "%s: cancel %s scan\n", __func__,
689 		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
690 			"active" : "passive");
691 
692 		/* clear bg scan NOPICK and mark cancel request */
693 		ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
694 		SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
695 		/* wake up the scan task */
696 		scan_signal(ss);
697 	}
698 	IEEE80211_UNLOCK(ic);
699 }
700 
701 /*
702  * Cancel any scan currently going on.
703  */
704 void
705 ieee80211_cancel_anyscan(struct ieee80211vap *vap)
706 {
707 	struct ieee80211com *ic = vap->iv_ic;
708 	struct ieee80211_scan_state *ss = ic->ic_scan;
709 
710 	IEEE80211_LOCK(ic);
711 	if ((ic->ic_flags & IEEE80211_F_SCAN) &&
712 	    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
713 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
714 		    "%s: cancel %s scan\n", __func__,
715 		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
716 			"active" : "passive");
717 
718 		/* clear bg scan NOPICK and mark cancel request */
719 		ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
720 		SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
721 		/* wake up the scan task */
722 		scan_signal(ss);
723 	}
724 	IEEE80211_UNLOCK(ic);
725 }
726 
727 /*
728  * Public access to scan_next for drivers that manage
729  * scanning themselves (e.g. for firmware-based devices).
730  */
731 void
732 ieee80211_scan_next(struct ieee80211vap *vap)
733 {
734 	struct ieee80211com *ic = vap->iv_ic;
735 	struct ieee80211_scan_state *ss = ic->ic_scan;
736 
737 	/* wake up the scan task */
738 	IEEE80211_LOCK(ic);
739 	scan_signal(ss);
740 	IEEE80211_UNLOCK(ic);
741 }
742 
743 /*
744  * Public access to scan_next for drivers that are not able to scan single
745  * channels (e.g. for firmware-based devices).
746  */
747 void
748 ieee80211_scan_done(struct ieee80211vap *vap)
749 {
750 	struct ieee80211com *ic = vap->iv_ic;
751 	struct ieee80211_scan_state *ss;
752 
753 	IEEE80211_LOCK(ic);
754 	ss = ic->ic_scan;
755 	ss->ss_next = ss->ss_last; /* all channels are complete */
756 	scan_signal(ss);
757 	IEEE80211_UNLOCK(ic);
758 }
759 
760 /*
761  * Probe the curent channel, if allowed, while scanning.
762  * If the channel is not marked passive-only then send
763  * a probe request immediately.  Otherwise mark state and
764  * listen for beacons on the channel; if we receive something
765  * then we'll transmit a probe request.
766  */
767 void
768 ieee80211_probe_curchan(struct ieee80211vap *vap, int force)
769 {
770 	struct ieee80211com *ic = vap->iv_ic;
771 	struct ieee80211_scan_state *ss = ic->ic_scan;
772 	struct ifnet *ifp = vap->iv_ifp;
773 	int i;
774 
775 	if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
776 		ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
777 		return;
778 	}
779 	/*
780 	 * Send directed probe requests followed by any
781 	 * broadcast probe request.
782 	 * XXX remove dependence on ic/vap->iv_bss
783 	 */
784 	for (i = 0; i < ss->ss_nssid; i++)
785 		ieee80211_send_probereq(vap->iv_bss,
786 			vap->iv_myaddr, ifp->if_broadcastaddr,
787 			ifp->if_broadcastaddr,
788 			ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
789 	if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
790 		ieee80211_send_probereq(vap->iv_bss,
791 			vap->iv_myaddr, ifp->if_broadcastaddr,
792 			ifp->if_broadcastaddr,
793 			"", 0);
794 }
795 
796 /*
797  * Scan curchan.  If this is an active scan and the channel
798  * is not marked passive then send probe request frame(s).
799  * Arrange for the channel change after maxdwell ticks.
800  */
801 static void
802 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
803 {
804 	struct ieee80211vap *vap  = ss->ss_vap;
805 
806 	IEEE80211_LOCK(vap->iv_ic);
807 	if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
808 		ieee80211_probe_curchan(vap, 0);
809 	callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
810 	    maxdwell, scan_signal, ss);
811 	IEEE80211_UNLOCK(vap->iv_ic);
812 }
813 
814 static void
815 scan_signal(void *arg)
816 {
817 	struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
818 
819 	IEEE80211_LOCK_ASSERT(ss->ss_ic);
820 
821 	cv_signal(&SCAN_PRIVATE(ss)->ss_scan_cv);
822 }
823 
824 /*
825  * Handle mindwell requirements completed; initiate a channel
826  * change to the next channel asap.
827  */
828 static void
829 scan_mindwell(struct ieee80211_scan_state *ss)
830 {
831 	struct ieee80211com *ic = ss->ss_ic;
832 
833 	IEEE80211_LOCK(ic);
834 	scan_signal(ss);
835 	IEEE80211_UNLOCK(ic);
836 }
837 
838 static void
839 scan_task(void *arg, int pending)
840 {
841 #define	ISCAN_REP	(ISCAN_MINDWELL | ISCAN_DISCARD)
842 	struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
843 	struct ieee80211vap *vap = ss->ss_vap;
844 	struct ieee80211com *ic = ss->ss_ic;
845 	struct ieee80211_channel *chan;
846 	unsigned long maxdwell, scanend;
847 	int scandone = 0;
848 
849 	IEEE80211_LOCK(ic);
850 	if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
851 	    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
852 		/* Cancelled before we started */
853 		goto done;
854 	}
855 
856 	if (ss->ss_next == ss->ss_last) {
857 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
858 			"%s: no channels to scan\n", __func__);
859 		goto done;
860 	}
861 
862 	if (vap->iv_opmode == IEEE80211_M_STA &&
863 	    vap->iv_state == IEEE80211_S_RUN) {
864 		if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
865 			/* Enable station power save mode */
866 			ieee80211_sta_pwrsave(vap, 1);
867 			/*
868 			 * Use an 1ms delay so the null data frame has a chance
869 			 * to go out.
870 			 * XXX Should use M_TXCB mechanism to eliminate this.
871 			 */
872 			cv_timedwait(&SCAN_PRIVATE(ss)->ss_scan_cv,
873 			    IEEE80211_LOCK_OBJ(ic), hz / 1000);
874 			if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
875 				goto done;
876 		}
877 	}
878 
879 	scanend = ticks + SCAN_PRIVATE(ss)->ss_duration;
880 	IEEE80211_UNLOCK(ic);
881 	ic->ic_scan_start(ic);		/* notify driver */
882 	IEEE80211_LOCK(ic);
883 
884 	for (;;) {
885 		scandone = (ss->ss_next >= ss->ss_last) ||
886 		    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0;
887 		if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
888 		    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT) ||
889 		     time_after(ticks + ss->ss_mindwell, scanend))
890 			break;
891 
892 		chan = ss->ss_chans[ss->ss_next++];
893 
894 		/*
895 		 * Watch for truncation due to the scan end time.
896 		 */
897 		if (time_after(ticks + ss->ss_maxdwell, scanend))
898 			maxdwell = scanend - ticks;
899 		else
900 			maxdwell = ss->ss_maxdwell;
901 
902 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
903 		    "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
904 		    __func__,
905 		    ieee80211_chan2ieee(ic, ic->ic_curchan),
906 		        channel_type(ic->ic_curchan),
907 		    ieee80211_chan2ieee(ic, chan), channel_type(chan),
908 		    (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
909 			(chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
910 			"active" : "passive",
911 		    ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
912 
913 		/*
914 		 * Potentially change channel and phy mode.
915 		 */
916 		ic->ic_curchan = chan;
917 		ic->ic_rt = ieee80211_get_ratetable(chan);
918 		IEEE80211_UNLOCK(ic);
919 		/*
920 		 * Perform the channel change and scan unlocked so the driver
921 		 * may sleep. Once set_channel returns the hardware has
922 		 * completed the channel change.
923 		 */
924 		ic->ic_set_channel(ic);
925 		ieee80211_radiotap_chan_change(ic);
926 
927 		/*
928 		 * Scan curchan.  Drivers for "intelligent hardware"
929 		 * override ic_scan_curchan to tell the device to do
930 		 * the work.  Otherwise we manage the work outselves;
931 		 * sending a probe request (as needed), and arming the
932 		 * timeout to switch channels after maxdwell ticks.
933 		 *
934 		 * scan_curchan should only pause for the time required to
935 		 * prepare/initiate the hardware for the scan (if at all), the
936 		 * below condvar is used to sleep for the channels dwell time
937 		 * and allows it to be signalled for abort.
938 		 */
939 		ic->ic_scan_curchan(ss, maxdwell);
940 		IEEE80211_LOCK(ic);
941 
942 		SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell;
943 		/* clear mindwell lock and initial channel change flush */
944 		SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
945 
946 		if ((SCAN_PRIVATE(ss)->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)))
947 			continue;
948 
949 		/* Wait to be signalled to scan the next channel */
950 		cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv, IEEE80211_LOCK_OBJ(ic));
951 	}
952 	if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
953 		goto done;
954 
955 	IEEE80211_UNLOCK(ic);
956 	ic->ic_scan_end(ic);		/* notify driver */
957 	IEEE80211_LOCK(ic);
958 
959 	/*
960 	 * Record scan complete time.  Note that we also do
961 	 * this when canceled so any background scan will
962 	 * not be restarted for a while.
963 	 */
964 	if (scandone)
965 		ic->ic_lastscan = ticks;
966 	/* return to the bss channel */
967 	if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
968 	    ic->ic_curchan != ic->ic_bsschan) {
969 		ieee80211_setupcurchan(ic, ic->ic_bsschan);
970 		IEEE80211_UNLOCK(ic);
971 		ic->ic_set_channel(ic);
972 		ieee80211_radiotap_chan_change(ic);
973 		IEEE80211_LOCK(ic);
974 	}
975 	/* clear internal flags and any indication of a pick */
976 	SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
977 	ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
978 
979 	/*
980 	 * If not canceled and scan completed, do post-processing.
981 	 * If the callback function returns 0, then it wants to
982 	 * continue/restart scanning.  Unfortunately we needed to
983 	 * notify the driver to end the scan above to avoid having
984 	 * rx frames alter the scan candidate list.
985 	 */
986 	if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 &&
987 	    !ss->ss_ops->scan_end(ss, vap) &&
988 	    (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
989 	    time_before(ticks + ss->ss_mindwell, scanend)) {
990 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
991 		    "%s: done, restart "
992 		    "[ticks %u, dwell min %lu scanend %lu]\n",
993 		    __func__,
994 		    ticks, ss->ss_mindwell, scanend);
995 		ss->ss_next = 0;	/* reset to begining */
996 		if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
997 			vap->iv_stats.is_scan_active++;
998 		else
999 			vap->iv_stats.is_scan_passive++;
1000 
1001 		ss->ss_ops->scan_restart(ss, vap);	/* XXX? */
1002 		ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
1003 		IEEE80211_UNLOCK(ic);
1004 		return;
1005 	}
1006 
1007 	/* past here, scandone is ``true'' if not in bg mode */
1008 	if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
1009 		scandone = 1;
1010 
1011 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1012 	    "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
1013 	    __func__, scandone ? "done" : "stopped",
1014 	    ticks, ss->ss_mindwell, scanend);
1015 
1016 	/*
1017 	 * Clear the SCAN bit first in case frames are
1018 	 * pending on the station power save queue.  If
1019 	 * we defer this then the dispatch of the frames
1020 	 * may generate a request to cancel scanning.
1021 	 */
1022 done:
1023 	ic->ic_flags &= ~IEEE80211_F_SCAN;
1024 	/*
1025 	 * Drop out of power save mode when a scan has
1026 	 * completed.  If this scan was prematurely terminated
1027 	 * because it is a background scan then don't notify
1028 	 * the ap; we'll either return to scanning after we
1029 	 * receive the beacon frame or we'll drop out of power
1030 	 * save mode because the beacon indicates we have frames
1031 	 * waiting for us.
1032 	 */
1033 	if (scandone) {
1034 		ieee80211_sta_pwrsave(vap, 0);
1035 		if (ss->ss_next >= ss->ss_last) {
1036 			ieee80211_notify_scan_done(vap);
1037 			ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
1038 		}
1039 	}
1040 	SCAN_PRIVATE(ss)->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
1041 	ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
1042 	IEEE80211_UNLOCK(ic);
1043 #undef ISCAN_REP
1044 }
1045 
1046 #ifdef IEEE80211_DEBUG
1047 static void
1048 dump_country(const uint8_t *ie)
1049 {
1050 	const struct ieee80211_country_ie *cie =
1051 	   (const struct ieee80211_country_ie *) ie;
1052 	int i, nbands, schan, nchan;
1053 
1054 	if (cie->len < 3) {
1055 		printf(" <bogus country ie, len %d>", cie->len);
1056 		return;
1057 	}
1058 	printf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]);
1059 	nbands = (cie->len - 3) / sizeof(cie->band[0]);
1060 	for (i = 0; i < nbands; i++) {
1061 		schan = cie->band[i].schan;
1062 		nchan = cie->band[i].nchan;
1063 		if (nchan != 1)
1064 			printf(" %u-%u,%u", schan, schan + nchan-1,
1065 			    cie->band[i].maxtxpwr);
1066 		else
1067 			printf(" %u,%u", schan, cie->band[i].maxtxpwr);
1068 	}
1069 	printf("]");
1070 }
1071 
1072 static void
1073 dump_probe_beacon(uint8_t subtype, int isnew,
1074 	const uint8_t mac[IEEE80211_ADDR_LEN],
1075 	const struct ieee80211_scanparams *sp, int rssi)
1076 {
1077 
1078 	printf("[%s] %s%s on chan %u (bss chan %u) ",
1079 	    ether_sprintf(mac), isnew ? "new " : "",
1080 	    ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT],
1081 	    sp->chan, sp->bchan);
1082 	ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
1083 	printf(" rssi %d\n", rssi);
1084 
1085 	if (isnew) {
1086 		printf("[%s] caps 0x%x bintval %u erp 0x%x",
1087 			ether_sprintf(mac), sp->capinfo, sp->bintval, sp->erp);
1088 		if (sp->country != NULL)
1089 			dump_country(sp->country);
1090 		printf("\n");
1091 	}
1092 }
1093 #endif /* IEEE80211_DEBUG */
1094 
1095 /*
1096  * Process a beacon or probe response frame.
1097  */
1098 void
1099 ieee80211_add_scan(struct ieee80211vap *vap,
1100 	const struct ieee80211_scanparams *sp,
1101 	const struct ieee80211_frame *wh,
1102 	int subtype, int rssi, int noise)
1103 {
1104 	struct ieee80211com *ic = vap->iv_ic;
1105 	struct ieee80211_scan_state *ss = ic->ic_scan;
1106 
1107 	/* XXX locking */
1108 	/*
1109 	 * Frames received during startup are discarded to avoid
1110 	 * using scan state setup on the initial entry to the timer
1111 	 * callback.  This can occur because the device may enable
1112 	 * rx prior to our doing the initial channel change in the
1113 	 * timer routine.
1114 	 */
1115 	if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
1116 		return;
1117 #ifdef IEEE80211_DEBUG
1118 	if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
1119 		dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
1120 #endif
1121 	if (ss->ss_ops != NULL &&
1122 	    ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise)) {
1123 		/*
1124 		 * If we've reached the min dwell time terminate
1125 		 * the timer so we'll switch to the next channel.
1126 		 */
1127 		if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
1128 		    time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
1129 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1130 			    "%s: chan %3d%c min dwell met (%u > %lu)\n",
1131 			    __func__,
1132 			    ieee80211_chan2ieee(ic, ic->ic_curchan),
1133 				channel_type(ic->ic_curchan),
1134 			    ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
1135 			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
1136 			/*
1137 			 * NB: trigger at next clock tick or wait for the
1138 			 * hardware.
1139 			 */
1140 			ic->ic_scan_mindwell(ss);
1141 		}
1142 	}
1143 }
1144 
1145 /*
1146  * Timeout/age scan cache entries; called from sta timeout
1147  * timer (XXX should be self-contained).
1148  */
1149 void
1150 ieee80211_scan_timeout(struct ieee80211com *ic)
1151 {
1152 	struct ieee80211_scan_state *ss = ic->ic_scan;
1153 
1154 	if (ss->ss_ops != NULL)
1155 		ss->ss_ops->scan_age(ss);
1156 }
1157 
1158 /*
1159  * Mark a scan cache entry after a successful associate.
1160  */
1161 void
1162 ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
1163 {
1164 	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1165 
1166 	if (ss->ss_ops != NULL) {
1167 		IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN,
1168 			mac, "%s",  __func__);
1169 		ss->ss_ops->scan_assoc_success(ss, mac);
1170 	}
1171 }
1172 
1173 /*
1174  * Demerit a scan cache entry after failing to associate.
1175  */
1176 void
1177 ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
1178 	const uint8_t mac[], int reason)
1179 {
1180 	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1181 
1182 	if (ss->ss_ops != NULL) {
1183 		IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac,
1184 			"%s: reason %u", __func__, reason);
1185 		ss->ss_ops->scan_assoc_fail(ss, mac, reason);
1186 	}
1187 }
1188 
1189 /*
1190  * Iterate over the contents of the scan cache.
1191  */
1192 void
1193 ieee80211_scan_iterate(struct ieee80211vap *vap,
1194 	ieee80211_scan_iter_func *f, void *arg)
1195 {
1196 	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1197 
1198 	if (ss->ss_ops != NULL)
1199 		ss->ss_ops->scan_iterate(ss, f, arg);
1200 }
1201 
1202 /*
1203  * Flush the contents of the scan cache.
1204  */
1205 void
1206 ieee80211_scan_flush(struct ieee80211vap *vap)
1207 {
1208 	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1209 
1210 	if (ss->ss_ops != NULL && ss->ss_vap == vap) {
1211 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n",  __func__);
1212 		ss->ss_ops->scan_flush(ss);
1213 	}
1214 }
1215 
1216 /*
1217  * Check the scan cache for an ap/channel to use; if that
1218  * fails then kick off a new scan.
1219  */
1220 struct ieee80211_channel *
1221 ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
1222 {
1223 	struct ieee80211_scan_state *ss = ic->ic_scan;
1224 
1225 	IEEE80211_LOCK_ASSERT(ic);
1226 
1227 	if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
1228 		/* XXX printf? */
1229 		return NULL;
1230 	}
1231 	if (ss->ss_ops->scan_pickchan == NULL) {
1232 		IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
1233 		    "%s: scan module does not support picking a channel, "
1234 		    "opmode %s\n", __func__, ss->ss_vap->iv_opmode);
1235 		return NULL;
1236 	}
1237 	return ss->ss_ops->scan_pickchan(ss, flags);
1238 }
1239