xref: /freebsd/sys/net80211/ieee80211_scan.c (revision 63d1fd5970ec814904aa0f4580b10a0d302d08b2)
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 /* XXX until it's implemented as attach ops */
51 #include <net80211/ieee80211_scan_sw.h>
52 
53 #include <net/bpf.h>
54 
55 /*
56  * Roaming-related defaults.  RSSI thresholds are as returned by the
57  * driver (.5dBm).  Transmit rate thresholds are IEEE rate codes (i.e
58  * .5M units) or MCS.
59  */
60 /* rssi thresholds */
61 #define	ROAM_RSSI_11A_DEFAULT		14	/* 11a bss */
62 #define	ROAM_RSSI_11B_DEFAULT		14	/* 11b bss */
63 #define	ROAM_RSSI_11BONLY_DEFAULT	14	/* 11b-only bss */
64 /* transmit rate thresholds */
65 #define	ROAM_RATE_11A_DEFAULT		2*12	/* 11a bss */
66 #define	ROAM_RATE_11B_DEFAULT		2*5	/* 11b bss */
67 #define	ROAM_RATE_11BONLY_DEFAULT	2*1	/* 11b-only bss */
68 #define	ROAM_RATE_HALF_DEFAULT		2*6	/* half-width 11a/g bss */
69 #define	ROAM_RATE_QUARTER_DEFAULT	2*3	/* quarter-width 11a/g bss */
70 #define	ROAM_MCS_11N_DEFAULT		(1 | IEEE80211_RATE_MCS) /* 11n bss */
71 #define	ROAM_MCS_11AC_DEFAULT		(1 | IEEE80211_RATE_MCS) /* 11ac bss; XXX not used yet */
72 
73 void
74 ieee80211_scan_attach(struct ieee80211com *ic)
75 {
76 	/*
77 	 * If there's no scan method pointer, attach the
78 	 * swscan set as a default.
79 	 */
80 	if (ic->ic_scan_methods == NULL)
81 		ieee80211_swscan_attach(ic);
82 	else
83 		ic->ic_scan_methods->sc_attach(ic);
84 }
85 
86 void
87 ieee80211_scan_detach(struct ieee80211com *ic)
88 {
89 
90 	/*
91 	 * Ideally we'd do the ss_ops detach call here;
92 	 * but then sc_detach() would need to be split in two.
93 	 *
94 	 * I'll do that later.
95 	 */
96 	ic->ic_scan_methods->sc_detach(ic);
97 }
98 
99 static const struct ieee80211_roamparam defroam[IEEE80211_MODE_MAX] = {
100 	[IEEE80211_MODE_11A]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
101 				    .rate = ROAM_RATE_11A_DEFAULT },
102 	[IEEE80211_MODE_11G]	= { .rssi = ROAM_RSSI_11B_DEFAULT,
103 				    .rate = ROAM_RATE_11B_DEFAULT },
104 	[IEEE80211_MODE_11B]	= { .rssi = ROAM_RSSI_11BONLY_DEFAULT,
105 				    .rate = ROAM_RATE_11BONLY_DEFAULT },
106 	[IEEE80211_MODE_TURBO_A]= { .rssi = ROAM_RSSI_11A_DEFAULT,
107 				    .rate = ROAM_RATE_11A_DEFAULT },
108 	[IEEE80211_MODE_TURBO_G]= { .rssi = ROAM_RSSI_11A_DEFAULT,
109 				    .rate = ROAM_RATE_11A_DEFAULT },
110 	[IEEE80211_MODE_STURBO_A]={ .rssi = ROAM_RSSI_11A_DEFAULT,
111 				    .rate = ROAM_RATE_11A_DEFAULT },
112 	[IEEE80211_MODE_HALF]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
113 				    .rate = ROAM_RATE_HALF_DEFAULT },
114 	[IEEE80211_MODE_QUARTER]= { .rssi = ROAM_RSSI_11A_DEFAULT,
115 				    .rate = ROAM_RATE_QUARTER_DEFAULT },
116 	[IEEE80211_MODE_11NA]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
117 				    .rate = ROAM_MCS_11N_DEFAULT },
118 	[IEEE80211_MODE_11NG]	= { .rssi = ROAM_RSSI_11B_DEFAULT,
119 				    .rate = ROAM_MCS_11N_DEFAULT },
120 	[IEEE80211_MODE_VHT_2GHZ]	= { .rssi = ROAM_RSSI_11B_DEFAULT,
121 				    .rate = ROAM_MCS_11AC_DEFAULT },
122 	[IEEE80211_MODE_VHT_5GHZ]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
123 				    .rate = ROAM_MCS_11AC_DEFAULT },
124 
125 };
126 
127 void
128 ieee80211_scan_vattach(struct ieee80211vap *vap)
129 {
130 	struct ieee80211com *ic = vap->iv_ic;
131 
132 	vap->iv_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz;
133 	vap->iv_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz;
134 	vap->iv_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz;
135 
136 	vap->iv_roaming = IEEE80211_ROAMING_AUTO;
137 	memcpy(vap->iv_roamparms, defroam, sizeof(defroam));
138 
139 	ic->ic_scan_methods->sc_vattach(vap);
140 }
141 
142 void
143 ieee80211_scan_vdetach(struct ieee80211vap *vap)
144 {
145 	struct ieee80211com *ic = vap->iv_ic;
146 	struct ieee80211_scan_state *ss;
147 
148 	IEEE80211_LOCK(ic);
149 	ss = ic->ic_scan;
150 
151 	ic->ic_scan_methods->sc_vdetach(vap);
152 
153 	if (ss != NULL && ss->ss_vap == vap) {
154 		if (ss->ss_ops != NULL) {
155 			ss->ss_ops->scan_detach(ss);
156 			ss->ss_ops = NULL;
157 		}
158 		ss->ss_vap = NULL;
159 	}
160 	IEEE80211_UNLOCK(ic);
161 }
162 
163 /*
164  * Simple-minded scanner module support.
165  */
166 static const char *scan_modnames[IEEE80211_OPMODE_MAX] = {
167 	"wlan_scan_sta",	/* IEEE80211_M_IBSS */
168 	"wlan_scan_sta",	/* IEEE80211_M_STA */
169 	"wlan_scan_wds",	/* IEEE80211_M_WDS */
170 	"wlan_scan_sta",	/* IEEE80211_M_AHDEMO */
171 	"wlan_scan_ap",		/* IEEE80211_M_HOSTAP */
172 	"wlan_scan_monitor",	/* IEEE80211_M_MONITOR */
173 	"wlan_scan_sta",	/* IEEE80211_M_MBSS */
174 };
175 static const struct ieee80211_scanner *scanners[IEEE80211_OPMODE_MAX];
176 
177 const struct ieee80211_scanner *
178 ieee80211_scanner_get(enum ieee80211_opmode mode)
179 {
180 	if (mode >= IEEE80211_OPMODE_MAX)
181 		return NULL;
182 	if (scanners[mode] == NULL)
183 		ieee80211_load_module(scan_modnames[mode]);
184 	return scanners[mode];
185 }
186 
187 void
188 ieee80211_scanner_register(enum ieee80211_opmode mode,
189 	const struct ieee80211_scanner *scan)
190 {
191 	if (mode >= IEEE80211_OPMODE_MAX)
192 		return;
193 	scanners[mode] = scan;
194 }
195 
196 void
197 ieee80211_scanner_unregister(enum ieee80211_opmode mode,
198 	const struct ieee80211_scanner *scan)
199 {
200 	if (mode >= IEEE80211_OPMODE_MAX)
201 		return;
202 	if (scanners[mode] == scan)
203 		scanners[mode] = NULL;
204 }
205 
206 void
207 ieee80211_scanner_unregister_all(const struct ieee80211_scanner *scan)
208 {
209 	int m;
210 
211 	for (m = 0; m < IEEE80211_OPMODE_MAX; m++)
212 		if (scanners[m] == scan)
213 			scanners[m] = NULL;
214 }
215 
216 /*
217  * Update common scanner state to reflect the current
218  * operating mode.  This is called when the state machine
219  * is transitioned to RUN state w/o scanning--e.g. when
220  * operating in monitor mode.  The purpose of this is to
221  * ensure later callbacks find ss_ops set to properly
222  * reflect current operating mode.
223  */
224 void
225 ieee80211_scan_update_locked(struct ieee80211vap *vap,
226 	const struct ieee80211_scanner *scan)
227 {
228 	struct ieee80211com *ic = vap->iv_ic;
229 	struct ieee80211_scan_state *ss = ic->ic_scan;
230 
231 	IEEE80211_LOCK_ASSERT(ic);
232 
233 #ifdef IEEE80211_DEBUG
234 	if (ss->ss_vap != vap || ss->ss_ops != scan) {
235 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
236 		    "%s: current scanner is <%s:%s>, switch to <%s:%s>\n",
237 		    __func__,
238 		    ss->ss_vap != NULL ?
239 			ss->ss_vap->iv_ifp->if_xname : "none",
240 		    ss->ss_vap != NULL ?
241 			ieee80211_opmode_name[ss->ss_vap->iv_opmode] : "none",
242 		    vap->iv_ifp->if_xname,
243 		    ieee80211_opmode_name[vap->iv_opmode]);
244 	}
245 #endif
246 	ss->ss_vap = vap;
247 	if (ss->ss_ops != scan) {
248 		/*
249 		 * Switch scanners; detach old, attach new.  Special
250 		 * case where a single scan module implements multiple
251 		 * policies by using different scan ops but a common
252 		 * core.  We assume if the old and new attach methods
253 		 * are identical then it's ok to just change ss_ops
254 		 * and not flush the internal state of the module.
255 		 */
256 		if (scan == NULL || ss->ss_ops == NULL ||
257 		    ss->ss_ops->scan_attach != scan->scan_attach) {
258 			if (ss->ss_ops != NULL)
259 				ss->ss_ops->scan_detach(ss);
260 			if (scan != NULL && !scan->scan_attach(ss)) {
261 				/* XXX attach failure */
262 				/* XXX stat+msg */
263 				scan = NULL;
264 			}
265 		}
266 		ss->ss_ops = scan;
267 	}
268 }
269 
270 void
271 ieee80211_scan_dump_channels(const struct ieee80211_scan_state *ss)
272 {
273 	struct ieee80211com *ic = ss->ss_ic;
274 	const char *sep;
275 	int i;
276 
277 	sep = "";
278 	for (i = ss->ss_next; i < ss->ss_last; i++) {
279 		const struct ieee80211_channel *c = ss->ss_chans[i];
280 
281 		printf("%s%u%c", sep, ieee80211_chan2ieee(ic, c),
282 		    ieee80211_channel_type_char(c));
283 		sep = ", ";
284 	}
285 }
286 
287 #ifdef IEEE80211_DEBUG
288 void
289 ieee80211_scan_dump(struct ieee80211_scan_state *ss)
290 {
291 	struct ieee80211vap *vap = ss->ss_vap;
292 
293 	if_printf(vap->iv_ifp, "scan set ");
294 	ieee80211_scan_dump_channels(ss);
295 	printf(" dwell min %lums max %lums\n",
296 	    ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(ss->ss_maxdwell));
297 }
298 #endif /* IEEE80211_DEBUG */
299 
300 void
301 ieee80211_scan_copy_ssid(struct ieee80211vap *vap, struct ieee80211_scan_state *ss,
302 	int nssid, const struct ieee80211_scan_ssid ssids[])
303 {
304 	if (nssid > IEEE80211_SCAN_MAX_SSID) {
305 		/* XXX printf */
306 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
307 		    "%s: too many ssid %d, ignoring all of them\n",
308 		    __func__, nssid);
309 		return;
310 	}
311 	memcpy(ss->ss_ssid, ssids, nssid * sizeof(ssids[0]));
312 	ss->ss_nssid = nssid;
313 }
314 
315 /*
316  * Start a scan unless one is already going.
317  */
318 int
319 ieee80211_start_scan(struct ieee80211vap *vap, int flags,
320 	u_int duration, u_int mindwell, u_int maxdwell,
321 	u_int nssid, const struct ieee80211_scan_ssid ssids[])
322 {
323 	const struct ieee80211_scanner *scan;
324 	struct ieee80211com *ic = vap->iv_ic;
325 
326 	scan = ieee80211_scanner_get(vap->iv_opmode);
327 	if (scan == NULL) {
328 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
329 		    "%s: no scanner support for %s mode\n",
330 		    __func__, ieee80211_opmode_name[vap->iv_opmode]);
331 		/* XXX stat */
332 		return 0;
333 	}
334 
335 	return ic->ic_scan_methods->sc_start_scan(scan, vap, flags, duration,
336 	    mindwell, maxdwell, nssid, ssids);
337 }
338 
339 /*
340  * Check the scan cache for an ap/channel to use; if that
341  * fails then kick off a new scan.
342  */
343 int
344 ieee80211_check_scan(struct ieee80211vap *vap, int flags,
345 	u_int duration, u_int mindwell, u_int maxdwell,
346 	u_int nssid, const struct ieee80211_scan_ssid ssids[])
347 {
348 	struct ieee80211com *ic = vap->iv_ic;
349 	struct ieee80211_scan_state *ss = ic->ic_scan;
350 	const struct ieee80211_scanner *scan;
351 	int result;
352 
353 	scan = ieee80211_scanner_get(vap->iv_opmode);
354 	if (scan == NULL) {
355 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
356 		    "%s: no scanner support for %s mode\n",
357 		    __func__, vap->iv_opmode);
358 		/* XXX stat */
359 		return 0;
360 	}
361 
362 	/*
363 	 * Check if there's a list of scan candidates already.
364 	 * XXX want more than the ap we're currently associated with
365 	 */
366 
367 	IEEE80211_LOCK(ic);
368 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
369 	    "%s: %s scan, %s%s%s%s%s\n"
370 	    , __func__
371 	    , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
372 	    , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
373 	    , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
374 	    , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
375 	    , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
376 	    , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
377 	);
378 
379 	if (ss->ss_ops != scan) {
380 		/* XXX re-use cache contents? e.g. adhoc<->sta */
381 		flags |= IEEE80211_SCAN_FLUSH;
382 	}
383 
384 	/*
385 	 * XXX TODO: separate things out a bit better.
386 	 */
387 	ieee80211_scan_update_locked(vap, scan);
388 
389 	result = ic->ic_scan_methods->sc_check_scan(scan, vap, flags, duration,
390 	    mindwell, maxdwell, nssid, ssids);
391 
392 	IEEE80211_UNLOCK(ic);
393 
394 	return (result);
395 }
396 
397 /*
398  * Check the scan cache for an ap/channel to use; if that fails
399  * then kick off a scan using the current settings.
400  */
401 int
402 ieee80211_check_scan_current(struct ieee80211vap *vap)
403 {
404 	return ieee80211_check_scan(vap,
405 	    IEEE80211_SCAN_ACTIVE,
406 	    IEEE80211_SCAN_FOREVER, 0, 0,
407 	    vap->iv_des_nssid, vap->iv_des_ssid);
408 }
409 
410 /*
411  * Restart a previous scan.  If the previous scan completed
412  * then we start again using the existing channel list.
413  */
414 int
415 ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
416 {
417 	struct ieee80211com *ic = vap->iv_ic;
418 	const struct ieee80211_scanner *scan;
419 
420 	// IEEE80211_UNLOCK_ASSERT(sc);
421 
422 	scan = ieee80211_scanner_get(vap->iv_opmode);
423 	if (scan == NULL) {
424 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
425 		    "%s: no scanner support for %s mode\n",
426 		    __func__, vap->iv_opmode);
427 		/* XXX stat */
428 		return 0;
429 	}
430 
431 	/*
432 	 * XXX TODO: pull apart the bgscan logic into whatever
433 	 * belongs here and whatever belongs in the software
434 	 * scanner.
435 	 */
436 	return (ic->ic_scan_methods->sc_bg_scan(scan, vap, flags));
437 }
438 
439 /*
440  * Cancel any scan currently going on for the specified vap.
441  */
442 void
443 ieee80211_cancel_scan(struct ieee80211vap *vap)
444 {
445 	struct ieee80211com *ic = vap->iv_ic;
446 
447 	ic->ic_scan_methods->sc_cancel_scan(vap);
448 }
449 
450 /*
451  * Cancel any scan currently going on.
452  *
453  * This is called during normal 802.11 data path to cancel
454  * a scan so a newly arrived normal data packet can be sent.
455  */
456 void
457 ieee80211_cancel_anyscan(struct ieee80211vap *vap)
458 {
459 	struct ieee80211com *ic = vap->iv_ic;
460 
461 	ic->ic_scan_methods->sc_cancel_anyscan(vap);
462 }
463 
464 /*
465  * Manually switch to the next channel in the channel list.
466  * Provided for drivers that manage scanning themselves
467  * (e.g. for firmware-based devices).
468  */
469 void
470 ieee80211_scan_next(struct ieee80211vap *vap)
471 {
472 	struct ieee80211com *ic = vap->iv_ic;
473 
474 	ic->ic_scan_methods->sc_scan_next(vap);
475 }
476 
477 /*
478  * Manually stop a scan that is currently running.
479  * Provided for drivers that are not able to scan single channels
480  * (e.g. for firmware-based devices).
481  */
482 void
483 ieee80211_scan_done(struct ieee80211vap *vap)
484 {
485 	struct ieee80211com *ic = vap->iv_ic;
486 	struct ieee80211_scan_state *ss;
487 
488 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
489 
490 	IEEE80211_LOCK(ic);
491 	ss = ic->ic_scan;
492 	ss->ss_next = ss->ss_last; /* all channels are complete */
493 
494 	ic->ic_scan_methods->sc_scan_done(vap);
495 
496 	IEEE80211_UNLOCK(ic);
497 }
498 
499 /*
500  * Probe the current channel, if allowed, while scanning.
501  * If the channel is not marked passive-only then send
502  * a probe request immediately.  Otherwise mark state and
503  * listen for beacons on the channel; if we receive something
504  * then we'll transmit a probe request.
505  */
506 void
507 ieee80211_probe_curchan(struct ieee80211vap *vap, int force)
508 {
509 	struct ieee80211com *ic = vap->iv_ic;
510 
511 	if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
512 		ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
513 		return;
514 	}
515 
516 	ic->ic_scan_methods->sc_scan_probe_curchan(vap, force);
517 }
518 
519 #ifdef IEEE80211_DEBUG
520 static void
521 dump_country(const uint8_t *ie)
522 {
523 	const struct ieee80211_country_ie *cie =
524 	   (const struct ieee80211_country_ie *) ie;
525 	int i, nbands, schan, nchan;
526 
527 	if (cie->len < 3) {
528 		printf(" <bogus country ie, len %d>", cie->len);
529 		return;
530 	}
531 	printf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]);
532 	nbands = (cie->len - 3) / sizeof(cie->band[0]);
533 	for (i = 0; i < nbands; i++) {
534 		schan = cie->band[i].schan;
535 		nchan = cie->band[i].nchan;
536 		if (nchan != 1)
537 			printf(" %u-%u,%u", schan, schan + nchan-1,
538 			    cie->band[i].maxtxpwr);
539 		else
540 			printf(" %u,%u", schan, cie->band[i].maxtxpwr);
541 	}
542 	printf("]");
543 }
544 
545 void
546 ieee80211_scan_dump_probe_beacon(uint8_t subtype, int isnew,
547 	const uint8_t mac[IEEE80211_ADDR_LEN],
548 	const struct ieee80211_scanparams *sp, int rssi)
549 {
550 
551 	printf("[%s] %s%s on chan %u (bss chan %u) ",
552 	    ether_sprintf(mac), isnew ? "new " : "",
553 	    ieee80211_mgt_subtype_name(subtype), sp->chan, sp->bchan);
554 	ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
555 	printf(" rssi %d\n", rssi);
556 
557 	if (isnew) {
558 		printf("[%s] caps 0x%x bintval %u erp 0x%x",
559 			ether_sprintf(mac), sp->capinfo, sp->bintval, sp->erp);
560 		if (sp->country != NULL)
561 			dump_country(sp->country);
562 		printf("\n");
563 	}
564 }
565 #endif /* IEEE80211_DEBUG */
566 
567 /*
568  * Process a beacon or probe response frame.
569  */
570 void
571 ieee80211_add_scan(struct ieee80211vap *vap,
572 	struct ieee80211_channel *curchan,
573 	const struct ieee80211_scanparams *sp,
574 	const struct ieee80211_frame *wh,
575 	int subtype, int rssi, int noise)
576 {
577 	struct ieee80211com *ic = vap->iv_ic;
578 
579 	return (ic->ic_scan_methods->sc_add_scan(vap, curchan, sp, wh, subtype,
580 	    rssi, noise));
581 }
582 
583 /*
584  * Timeout/age scan cache entries; called from sta timeout
585  * timer (XXX should be self-contained).
586  */
587 void
588 ieee80211_scan_timeout(struct ieee80211com *ic)
589 {
590 	struct ieee80211_scan_state *ss = ic->ic_scan;
591 
592 	if (ss->ss_ops != NULL)
593 		ss->ss_ops->scan_age(ss);
594 }
595 
596 /*
597  * Mark a scan cache entry after a successful associate.
598  */
599 void
600 ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
601 {
602 	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
603 
604 	if (ss->ss_ops != NULL) {
605 		IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN,
606 			mac, "%s",  __func__);
607 		ss->ss_ops->scan_assoc_success(ss, mac);
608 	}
609 }
610 
611 /*
612  * Demerit a scan cache entry after failing to associate.
613  */
614 void
615 ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
616 	const uint8_t mac[], int reason)
617 {
618 	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
619 
620 	if (ss->ss_ops != NULL) {
621 		IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac,
622 			"%s: reason %u", __func__, reason);
623 		ss->ss_ops->scan_assoc_fail(ss, mac, reason);
624 	}
625 }
626 
627 /*
628  * Iterate over the contents of the scan cache.
629  */
630 void
631 ieee80211_scan_iterate(struct ieee80211vap *vap,
632 	ieee80211_scan_iter_func *f, void *arg)
633 {
634 	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
635 
636 	if (ss->ss_ops != NULL)
637 		ss->ss_ops->scan_iterate(ss, f, arg);
638 }
639 
640 /*
641  * Flush the contents of the scan cache.
642  */
643 void
644 ieee80211_scan_flush(struct ieee80211vap *vap)
645 {
646 	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
647 
648 	if (ss->ss_ops != NULL && ss->ss_vap == vap) {
649 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n",  __func__);
650 		ss->ss_ops->scan_flush(ss);
651 	}
652 }
653 
654 /*
655  * Check the scan cache for an ap/channel to use; if that
656  * fails then kick off a new scan.
657  */
658 struct ieee80211_channel *
659 ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
660 {
661 	struct ieee80211_scan_state *ss = ic->ic_scan;
662 
663 	IEEE80211_LOCK_ASSERT(ic);
664 
665 	if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
666 		/* XXX printf? */
667 		return NULL;
668 	}
669 	if (ss->ss_ops->scan_pickchan == NULL) {
670 		IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
671 		    "%s: scan module does not support picking a channel, "
672 		    "opmode %s\n", __func__, ss->ss_vap->iv_opmode);
673 		return NULL;
674 	}
675 	return ss->ss_ops->scan_pickchan(ss, flags);
676 }
677