1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2002-2009 Sam Leffler, Errno Consulting
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29/*
30 * IEEE 802.11 station scanning support.
31 */
32#include "opt_wlan.h"
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/kernel.h>
37#include <sys/endian.h>
38#include <sys/malloc.h>
39#include <sys/module.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#include <net80211/ieee80211_input.h>
50#include <net80211/ieee80211_regdomain.h>
51#ifdef IEEE80211_SUPPORT_TDMA
52#include <net80211/ieee80211_tdma.h>
53#endif
54#ifdef IEEE80211_SUPPORT_MESH
55#include <net80211/ieee80211_mesh.h>
56#endif
57#include <net80211/ieee80211_ratectl.h>
58#include <net80211/ieee80211_vht.h>
59
60#include <net/bpf.h>
61
62/*
63 * Parameters for managing cache entries:
64 *
65 * o a station with STA_FAILS_MAX failures is not considered
66 *   when picking a candidate
67 * o a station that hasn't had an update in STA_PURGE_SCANS
68 *   (background) scans is discarded
69 * o after STA_FAILS_AGE seconds we clear the failure count
70 */
71#define	STA_FAILS_MAX	2		/* assoc failures before ignored */
72#define	STA_FAILS_AGE	(2*60)		/* time before clearing fails (secs) */
73#define	STA_PURGE_SCANS	2		/* age for purging entries (scans) */
74
75/* XXX tunable */
76#define	STA_RSSI_MIN	8		/* min acceptable rssi */
77#define	STA_RSSI_MAX	40		/* max rssi for comparison */
78
79struct sta_entry {
80	struct ieee80211_scan_entry base;
81	TAILQ_ENTRY(sta_entry) se_list;
82	LIST_ENTRY(sta_entry) se_hash;
83	uint8_t		se_fails;		/* failure to associate count */
84	uint8_t		se_seen;		/* seen during current scan */
85	uint8_t		se_notseen;		/* not seen in previous scans */
86	uint8_t		se_flags;
87#define	STA_DEMOTE11B	0x01			/* match w/ demoted 11b chan */
88	uint32_t	se_avgrssi;		/* LPF rssi state */
89	unsigned long	se_lastupdate;		/* time of last update */
90	unsigned long	se_lastfail;		/* time of last failure */
91	unsigned long	se_lastassoc;		/* time of last association */
92	u_int		se_scangen;		/* iterator scan gen# */
93	u_int		se_countrygen;		/* gen# of last cc notify */
94};
95
96#define	STA_HASHSIZE	32
97/* simple hash is enough for variation of macaddr */
98#define	STA_HASH(addr)	\
99	(((const uint8_t *)(addr))[IEEE80211_ADDR_LEN - 1] % STA_HASHSIZE)
100
101#define	MAX_IEEE_CHAN	256			/* max acceptable IEEE chan # */
102CTASSERT(MAX_IEEE_CHAN >= 256);
103
104struct sta_table {
105	ieee80211_scan_table_lock_t st_lock;	/* on scan table */
106	TAILQ_HEAD(, sta_entry) st_entry;	/* all entries */
107	LIST_HEAD(, sta_entry) st_hash[STA_HASHSIZE];
108	ieee80211_scan_iter_lock_t st_scanlock;		/* on st_scaniter */
109	u_int		st_scaniter;		/* gen# for iterator */
110	u_int		st_scangen;		/* scan generation # */
111	int		st_newscan;
112	/* ap-related state */
113	int		st_maxrssi[MAX_IEEE_CHAN];
114};
115
116static void sta_flush_table(struct sta_table *);
117/*
118 * match_bss returns a bitmask describing if an entry is suitable
119 * for use.  If non-zero the entry was deemed not suitable and it's
120 * contents explains why.  The following flags are or'd to this
121 * mask and can be used to figure out why the entry was rejected.
122 */
123#define	MATCH_CHANNEL		0x00001	/* channel mismatch */
124#define	MATCH_CAPINFO		0x00002	/* capabilities mismatch, e.g. no ess */
125#define	MATCH_PRIVACY		0x00004	/* privacy mismatch */
126#define	MATCH_RATE		0x00008	/* rate set mismatch */
127#define	MATCH_SSID		0x00010	/* ssid mismatch */
128#define	MATCH_BSSID		0x00020	/* bssid mismatch */
129#define	MATCH_FAILS		0x00040	/* too many failed auth attempts */
130#define	MATCH_NOTSEEN		0x00080	/* not seen in recent scans */
131#define	MATCH_RSSI		0x00100	/* rssi deemed too low to use */
132#define	MATCH_CC		0x00200	/* country code mismatch */
133#ifdef IEEE80211_SUPPORT_TDMA
134#define	MATCH_TDMA_NOIE		0x00400	/* no TDMA ie */
135#define	MATCH_TDMA_NOTMASTER	0x00800	/* not TDMA master */
136#define	MATCH_TDMA_NOSLOT	0x01000	/* all TDMA slots occupied */
137#define	MATCH_TDMA_LOCAL	0x02000	/* local address */
138#define	MATCH_TDMA_VERSION	0x04000	/* protocol version mismatch */
139#endif
140#define	MATCH_MESH_NOID		0x10000	/* no MESHID ie */
141#define	MATCH_MESHID		0x20000	/* meshid mismatch */
142static int match_bss(struct ieee80211vap *,
143	const struct ieee80211_scan_state *, struct sta_entry *, int);
144static void adhoc_age(struct ieee80211_scan_state *);
145
146static __inline int
147isocmp(const uint8_t cc1[], const uint8_t cc2[])
148{
149     return (cc1[0] == cc2[0] && cc1[1] == cc2[1]);
150}
151
152/* number of references from net80211 layer */
153static	int nrefs = 0;
154/*
155 * Module glue.
156 */
157IEEE80211_SCANNER_MODULE(sta, 1);
158
159/*
160 * Attach prior to any scanning work.
161 */
162static int
163sta_attach(struct ieee80211_scan_state *ss)
164{
165	struct sta_table *st;
166
167	st = (struct sta_table *) IEEE80211_MALLOC(sizeof(struct sta_table),
168		M_80211_SCAN,
169		IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
170	if (st == NULL)
171		return 0;
172	IEEE80211_SCAN_TABLE_LOCK_INIT(st, "scantable");
173	IEEE80211_SCAN_ITER_LOCK_INIT(st, "scangen");
174	TAILQ_INIT(&st->st_entry);
175	ss->ss_priv = st;
176	nrefs++;			/* NB: we assume caller locking */
177	return 1;
178}
179
180/*
181 * Cleanup any private state.
182 */
183static int
184sta_detach(struct ieee80211_scan_state *ss)
185{
186	struct sta_table *st = ss->ss_priv;
187
188	if (st != NULL) {
189		sta_flush_table(st);
190		IEEE80211_SCAN_TABLE_LOCK_DESTROY(st);
191		IEEE80211_SCAN_ITER_LOCK_DESTROY(st);
192		IEEE80211_FREE(st, M_80211_SCAN);
193		KASSERT(nrefs > 0, ("imbalanced attach/detach"));
194		nrefs--;		/* NB: we assume caller locking */
195	}
196	return 1;
197}
198
199/*
200 * Flush all per-scan state.
201 */
202static int
203sta_flush(struct ieee80211_scan_state *ss)
204{
205	struct sta_table *st = ss->ss_priv;
206
207	IEEE80211_SCAN_TABLE_LOCK(st);
208	sta_flush_table(st);
209	IEEE80211_SCAN_TABLE_UNLOCK(st);
210	ss->ss_last = 0;
211	return 0;
212}
213
214/*
215 * Flush all entries in the scan cache.
216 */
217static void
218sta_flush_table(struct sta_table *st)
219{
220	struct sta_entry *se, *next;
221
222	TAILQ_FOREACH_SAFE(se, &st->st_entry, se_list, next) {
223		TAILQ_REMOVE(&st->st_entry, se, se_list);
224		LIST_REMOVE(se, se_hash);
225		ieee80211_ies_cleanup(&se->base.se_ies);
226		IEEE80211_FREE(se, M_80211_SCAN);
227	}
228	memset(st->st_maxrssi, 0, sizeof(st->st_maxrssi));
229}
230
231/*
232 * Process a beacon or probe response frame; create an
233 * entry in the scan cache or update any previous entry.
234 */
235static int
236sta_add(struct ieee80211_scan_state *ss,
237	struct ieee80211_channel *curchan,
238	const struct ieee80211_scanparams *sp,
239	const struct ieee80211_frame *wh,
240	int subtype, int rssi, int noise)
241{
242#define	ISPROBE(_st)	((_st) == IEEE80211_FC0_SUBTYPE_PROBE_RESP)
243#define	PICK1ST(_ss) \
244	((ss->ss_flags & (IEEE80211_SCAN_PICK1ST | IEEE80211_SCAN_GOTPICK)) == \
245	IEEE80211_SCAN_PICK1ST)
246	struct sta_table *st = ss->ss_priv;
247	const uint8_t *macaddr = wh->i_addr2;
248	struct ieee80211vap *vap = ss->ss_vap;
249	struct ieee80211com *ic = vap->iv_ic;
250	struct ieee80211_channel *c;
251	struct sta_entry *se;
252	struct ieee80211_scan_entry *ise;
253	int hash;
254
255	hash = STA_HASH(macaddr);
256
257	IEEE80211_SCAN_TABLE_LOCK(st);
258	LIST_FOREACH(se, &st->st_hash[hash], se_hash)
259		if (IEEE80211_ADDR_EQ(se->base.se_macaddr, macaddr))
260			goto found;
261	se = (struct sta_entry *) IEEE80211_MALLOC(sizeof(struct sta_entry),
262		M_80211_SCAN, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
263	if (se == NULL) {
264		IEEE80211_SCAN_TABLE_UNLOCK(st);
265		return 0;
266	}
267	se->se_scangen = st->st_scaniter-1;
268	se->se_avgrssi = IEEE80211_RSSI_DUMMY_MARKER;
269	IEEE80211_ADDR_COPY(se->base.se_macaddr, macaddr);
270	TAILQ_INSERT_TAIL(&st->st_entry, se, se_list);
271	LIST_INSERT_HEAD(&st->st_hash[hash], se, se_hash);
272found:
273	ise = &se->base;
274	/* XXX ap beaconing multiple ssid w/ same bssid */
275	if (sp->ssid[1] != 0 &&
276	    (ISPROBE(subtype) || ise->se_ssid[1] == 0))
277		memcpy(ise->se_ssid, sp->ssid, 2+sp->ssid[1]);
278	KASSERT(sp->rates[1] <= IEEE80211_RATE_MAXSIZE,
279		("rate set too large: %u", sp->rates[1]));
280	memcpy(ise->se_rates, sp->rates, 2+sp->rates[1]);
281	if (sp->xrates != NULL) {
282		/* XXX validate xrates[1] */
283		KASSERT(sp->xrates[1] <= IEEE80211_RATE_MAXSIZE,
284			("xrate set too large: %u", sp->xrates[1]));
285		memcpy(ise->se_xrates, sp->xrates, 2+sp->xrates[1]);
286	} else
287		ise->se_xrates[1] = 0;
288	IEEE80211_ADDR_COPY(ise->se_bssid, wh->i_addr3);
289	if ((sp->status & IEEE80211_BPARSE_OFFCHAN) == 0) {
290		/*
291		 * Record rssi data using extended precision LPF filter.
292		 *
293		 * NB: use only on-channel data to insure we get a good
294		 *     estimate of the signal we'll see when associated.
295		 */
296		IEEE80211_RSSI_LPF(se->se_avgrssi, rssi);
297		ise->se_rssi = IEEE80211_RSSI_GET(se->se_avgrssi);
298		ise->se_noise = noise;
299	}
300	memcpy(ise->se_tstamp.data, sp->tstamp, sizeof(ise->se_tstamp));
301	ise->se_intval = sp->bintval;
302	ise->se_capinfo = sp->capinfo;
303#ifdef IEEE80211_SUPPORT_MESH
304	if (sp->meshid != NULL && sp->meshid[1] != 0)
305		memcpy(ise->se_meshid, sp->meshid, 2+sp->meshid[1]);
306#endif
307	/*
308	 * Beware of overriding se_chan for frames seen
309	 * off-channel; this can cause us to attempt an
310	 * association on the wrong channel.
311	 */
312	if (sp->status & IEEE80211_BPARSE_OFFCHAN) {
313		/*
314		 * Off-channel, locate the home/bss channel for the sta
315		 * using the value broadcast in the DSPARMS ie.  We know
316		 * sp->chan has this value because it's used to calculate
317		 * IEEE80211_BPARSE_OFFCHAN.
318		 */
319		c = ieee80211_find_channel_byieee(ic, sp->chan,
320		    curchan->ic_flags);
321		if (c != NULL) {
322			ise->se_chan = c;
323		} else if (ise->se_chan == NULL) {
324			/* should not happen, pick something */
325			ise->se_chan = curchan;
326		}
327	} else
328		ise->se_chan = curchan;
329
330	/* VHT demotion */
331	if (IEEE80211_IS_CHAN_VHT(ise->se_chan) && sp->vhtcap == NULL) {
332		IEEE80211_DPRINTF(vap, IEEE80211_MSG_11N,
333		    "%s: demoting VHT->HT %d/0x%08x\n",
334		    __func__, ise->se_chan->ic_freq, ise->se_chan->ic_flags);
335		/* Demote legacy networks to a non-VHT channel. */
336		c = ieee80211_find_channel(ic, ise->se_chan->ic_freq,
337		    ise->se_chan->ic_flags & ~IEEE80211_CHAN_VHT);
338		KASSERT(c != NULL,
339		    ("no non-VHT channel %u", ise->se_chan->ic_ieee));
340		ise->se_chan = c;
341	}
342
343	/* HT demotion */
344	if (IEEE80211_IS_CHAN_HT(ise->se_chan) && sp->htcap == NULL) {
345		/* Demote legacy networks to a non-HT channel. */
346		IEEE80211_DPRINTF(vap, IEEE80211_MSG_11N,
347		    "%s: demoting HT->legacy %d/0x%08x\n",
348		    __func__, ise->se_chan->ic_freq, ise->se_chan->ic_flags);
349		c = ieee80211_find_channel(ic, ise->se_chan->ic_freq,
350		    ise->se_chan->ic_flags & ~IEEE80211_CHAN_HT);
351		KASSERT(c != NULL,
352		    ("no legacy channel %u", ise->se_chan->ic_ieee));
353		ise->se_chan = c;
354	}
355
356	ise->se_fhdwell = sp->fhdwell;
357	ise->se_fhindex = sp->fhindex;
358	ise->se_erp = sp->erp;
359	ise->se_timoff = sp->timoff;
360	if (sp->tim != NULL) {
361		const struct ieee80211_tim_ie *tim =
362		    (const struct ieee80211_tim_ie *) sp->tim;
363		ise->se_dtimperiod = tim->tim_period;
364	}
365	if (sp->country != NULL) {
366		const struct ieee80211_country_ie *cie =
367		    (const struct ieee80211_country_ie *) sp->country;
368		/*
369		 * If 11d is enabled and we're attempting to join a bss
370		 * that advertises it's country code then compare our
371		 * current settings to what we fetched from the country ie.
372		 * If our country code is unspecified or different then
373		 * dispatch an event to user space that identifies the
374		 * country code so our regdomain config can be changed.
375		 */
376		/* XXX only for STA mode? */
377		if ((IEEE80211_IS_CHAN_11D(ise->se_chan) ||
378		    (vap->iv_flags_ext & IEEE80211_FEXT_DOTD)) &&
379		    (ic->ic_regdomain.country == CTRY_DEFAULT ||
380		     !isocmp(cie->cc, ic->ic_regdomain.isocc))) {
381			/* only issue one notify event per scan */
382			if (se->se_countrygen != st->st_scangen) {
383				ieee80211_notify_country(vap, ise->se_bssid,
384				    cie->cc);
385				se->se_countrygen = st->st_scangen;
386			}
387		}
388		ise->se_cc[0] = cie->cc[0];
389		ise->se_cc[1] = cie->cc[1];
390	}
391	/* NB: no need to setup ie ptrs; they are not (currently) used */
392	(void) ieee80211_ies_init(&ise->se_ies, sp->ies, sp->ies_len);
393
394	/* clear failure count after STA_FAIL_AGE passes */
395	if (se->se_fails && (ticks - se->se_lastfail) > STA_FAILS_AGE*hz) {
396		se->se_fails = 0;
397		IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, macaddr,
398		    "%s: fails %u", __func__, se->se_fails);
399	}
400
401	se->se_lastupdate = ticks;		/* update time */
402	se->se_seen = 1;
403	se->se_notseen = 0;
404
405	KASSERT(sizeof(sp->bchan) == 1, ("bchan size"));
406	if (rssi > st->st_maxrssi[sp->bchan])
407		st->st_maxrssi[sp->bchan] = rssi;
408
409	IEEE80211_SCAN_TABLE_UNLOCK(st);
410
411	/*
412	 * If looking for a quick choice and nothing's
413	 * been found check here.
414	 */
415	if (PICK1ST(ss) && match_bss(vap, ss, se, IEEE80211_MSG_SCAN) == 0)
416		ss->ss_flags |= IEEE80211_SCAN_GOTPICK;
417
418	return 1;
419#undef PICK1ST
420#undef ISPROBE
421}
422
423/*
424 * Check if a channel is excluded by user request.
425 */
426static int
427isexcluded(struct ieee80211vap *vap, const struct ieee80211_channel *c)
428{
429	return (isclr(vap->iv_ic->ic_chan_active, c->ic_ieee) ||
430	    (vap->iv_des_chan != IEEE80211_CHAN_ANYC &&
431	     c->ic_freq != vap->iv_des_chan->ic_freq));
432}
433
434static struct ieee80211_channel *
435find11gchannel(struct ieee80211com *ic, int i, int freq)
436{
437	struct ieee80211_channel *c;
438	int j;
439
440	/*
441	 * The normal ordering in the channel list is b channel
442	 * immediately followed by g so optimize the search for
443	 * this.  We'll still do a full search just in case.
444	 */
445	for (j = i+1; j < ic->ic_nchans; j++) {
446		c = &ic->ic_channels[j];
447		if (c->ic_freq == freq && IEEE80211_IS_CHAN_G(c))
448			return c;
449	}
450	for (j = 0; j < i; j++) {
451		c = &ic->ic_channels[j];
452		if (c->ic_freq == freq && IEEE80211_IS_CHAN_G(c))
453			return c;
454	}
455	return NULL;
456}
457
458static const u_int chanflags[IEEE80211_MODE_MAX] = {
459	[IEEE80211_MODE_AUTO]	  = IEEE80211_CHAN_B,
460	[IEEE80211_MODE_11A]	  = IEEE80211_CHAN_A,
461	[IEEE80211_MODE_11B]	  = IEEE80211_CHAN_B,
462	[IEEE80211_MODE_11G]	  = IEEE80211_CHAN_G,
463	[IEEE80211_MODE_FH]	  = IEEE80211_CHAN_FHSS,
464	/* check base channel */
465	[IEEE80211_MODE_TURBO_A]  = IEEE80211_CHAN_A,
466	[IEEE80211_MODE_TURBO_G]  = IEEE80211_CHAN_G,
467	[IEEE80211_MODE_STURBO_A] = IEEE80211_CHAN_ST,
468	[IEEE80211_MODE_HALF]	  = IEEE80211_CHAN_HALF,
469	[IEEE80211_MODE_QUARTER]  = IEEE80211_CHAN_QUARTER,
470	/* check legacy */
471	[IEEE80211_MODE_11NA]	  = IEEE80211_CHAN_A,
472	[IEEE80211_MODE_11NG]	  = IEEE80211_CHAN_G,
473	[IEEE80211_MODE_VHT_5GHZ] = IEEE80211_CHAN_A,
474	[IEEE80211_MODE_VHT_2GHZ] = IEEE80211_CHAN_G,
475};
476
477static void
478add_channels(struct ieee80211vap *vap,
479	struct ieee80211_scan_state *ss,
480	enum ieee80211_phymode mode, const uint16_t freq[], int nfreq)
481{
482	struct ieee80211com *ic = vap->iv_ic;
483	struct ieee80211_channel *c, *cg;
484	u_int modeflags;
485	int i;
486
487	KASSERT(mode < nitems(chanflags), ("Unexpected mode %u", mode));
488	modeflags = chanflags[mode];
489	for (i = 0; i < nfreq; i++) {
490		if (ss->ss_last >= IEEE80211_SCAN_MAX)
491			break;
492
493		c = ieee80211_find_channel(ic, freq[i], modeflags);
494		if (c == NULL || isexcluded(vap, c))
495			continue;
496		if (mode == IEEE80211_MODE_AUTO) {
497			KASSERT(IEEE80211_IS_CHAN_B(c),
498			    ("%s: wrong channel for 'auto' mode %u / %u\n",
499			    __func__, c->ic_freq, c->ic_flags));
500
501			/*
502			 * XXX special-case 11b/g channels so we select
503			 *     the g channel if both are present.
504			 */
505			if ((cg = find11gchannel(ic, i, c->ic_freq)) != NULL)
506				c = cg;
507		}
508		ss->ss_chans[ss->ss_last++] = c;
509	}
510}
511
512struct scanlist {
513	uint16_t	mode;
514	uint16_t	count;
515	const uint16_t	*list;
516};
517
518static int
519checktable(const struct scanlist *scan, const struct ieee80211_channel *c)
520{
521	int i;
522
523	for (; scan->list != NULL; scan++) {
524		for (i = 0; i < scan->count; i++)
525			if (scan->list[i] == c->ic_freq)
526				return 1;
527	}
528	return 0;
529}
530
531static int
532onscanlist(const struct ieee80211_scan_state *ss,
533	const struct ieee80211_channel *c)
534{
535	int i;
536
537	for (i = 0; i < ss->ss_last; i++)
538		if (ss->ss_chans[i] == c)
539			return 1;
540	return 0;
541}
542
543static void
544sweepchannels(struct ieee80211_scan_state *ss, struct ieee80211vap *vap,
545	const struct scanlist table[])
546{
547	struct ieee80211com *ic = vap->iv_ic;
548	struct ieee80211_channel *c;
549	int i;
550
551	for (i = 0; i < ic->ic_nchans; i++) {
552		if (ss->ss_last >= IEEE80211_SCAN_MAX)
553			break;
554
555		c = &ic->ic_channels[i];
556		/*
557		 * Ignore dynamic turbo channels; we scan them
558		 * in normal mode (i.e. not boosted).  Likewise
559		 * for HT/VHT channels, they get scanned using
560		 * legacy rates.
561		 */
562		if (IEEE80211_IS_CHAN_DTURBO(c) || IEEE80211_IS_CHAN_HT(c) ||
563		    IEEE80211_IS_CHAN_VHT(c))
564			continue;
565
566		/*
567		 * If a desired mode was specified, scan only
568		 * channels that satisfy that constraint.
569		 */
570		if (vap->iv_des_mode != IEEE80211_MODE_AUTO &&
571		    vap->iv_des_mode != ieee80211_chan2mode(c))
572			continue;
573
574		/*
575		 * Skip channels excluded by user request.
576		 */
577		if (isexcluded(vap, c))
578			continue;
579
580		/*
581		 * Add the channel unless it is listed in the
582		 * fixed scan order tables.  This insures we
583		 * don't sweep back in channels we filtered out
584		 * above.
585		 */
586		if (checktable(table, c))
587			continue;
588
589		/* Add channel to scanning list. */
590		ss->ss_chans[ss->ss_last++] = c;
591	}
592	/*
593	 * Explicitly add any desired channel if:
594	 * - not already on the scan list
595	 * - allowed by any desired mode constraint
596	 * - there is space in the scan list
597	 * This allows the channel to be used when the filtering
598	 * mechanisms would otherwise elide it (e.g HT, turbo).
599	 */
600	c = vap->iv_des_chan;
601	if (c != IEEE80211_CHAN_ANYC &&
602	    !onscanlist(ss, c) &&
603	    (vap->iv_des_mode == IEEE80211_MODE_AUTO ||
604	     vap->iv_des_mode == ieee80211_chan2mode(c)) &&
605	    ss->ss_last < IEEE80211_SCAN_MAX)
606		ss->ss_chans[ss->ss_last++] = c;
607}
608
609static void
610makescanlist(struct ieee80211_scan_state *ss, struct ieee80211vap *vap,
611	const struct scanlist table[])
612{
613	const struct scanlist *scan;
614	enum ieee80211_phymode mode;
615
616	ss->ss_last = 0;
617	/*
618	 * Use the table of ordered channels to construct the list
619	 * of channels for scanning.  Any channels in the ordered
620	 * list not in the master list will be discarded.
621	 */
622	for (scan = table; scan->list != NULL; scan++) {
623		mode = scan->mode;
624
625		switch (mode) {
626		case IEEE80211_MODE_11B:
627			if (vap->iv_des_mode == IEEE80211_MODE_11B)
628				break;
629
630			/*
631			 * The scan table marks 2.4Ghz channels as b
632			 * so if the desired mode is 11g / 11ng / 11acg,
633			 * then use the 11b channel list but upgrade the mode.
634			 *
635			 * NB: 11b -> AUTO lets add_channels upgrade an
636			 * 11b channel to 11g if available.
637			 */
638			if (vap->iv_des_mode == IEEE80211_MODE_AUTO ||
639			    vap->iv_des_mode == IEEE80211_MODE_11G ||
640			    vap->iv_des_mode == IEEE80211_MODE_11NG ||
641			    vap->iv_des_mode == IEEE80211_MODE_VHT_2GHZ) {
642				mode = vap->iv_des_mode;
643				break;
644			}
645
646			continue;
647		case IEEE80211_MODE_11A:
648			/* Use 11a channel list for 11na / 11ac modes */
649			if (vap->iv_des_mode == IEEE80211_MODE_11NA ||
650			    vap->iv_des_mode == IEEE80211_MODE_VHT_5GHZ) {
651				mode = vap->iv_des_mode;
652				break;
653			}
654
655			/* FALLTHROUGH */
656		default:
657			/*
658			 * If a desired mode was specified, scan only
659			 * channels that satisfy that constraint.
660			 */
661			if (vap->iv_des_mode != IEEE80211_MODE_AUTO &&
662			    vap->iv_des_mode != mode)
663				continue;
664		}
665
666#ifdef IEEE80211_F_XR
667		/* XR does not operate on turbo channels */
668		if ((vap->iv_flags & IEEE80211_F_XR) &&
669		    (mode == IEEE80211_MODE_TURBO_A ||
670		     mode == IEEE80211_MODE_TURBO_G ||
671		     mode == IEEE80211_MODE_STURBO_A))
672			continue;
673#endif
674		/*
675		 * Add the list of the channels; any that are not
676		 * in the master channel list will be discarded.
677		 */
678		add_channels(vap, ss, mode, scan->list, scan->count);
679	}
680
681	/*
682	 * Add the channels from the ic that are not present
683	 * in the table.
684	 */
685	sweepchannels(ss, vap, table);
686}
687
688static const uint16_t rcl1[] =		/* 8 FCC channel: 52, 56, 60, 64, 36, 40, 44, 48 */
689{ 5260, 5280, 5300, 5320, 5180, 5200, 5220, 5240 };
690static const uint16_t rcl2[] =		/* 4 MKK channels: 34, 38, 42, 46 */
691{ 5170, 5190, 5210, 5230 };
692static const uint16_t rcl3[] =		/* 2.4Ghz ch: 1,6,11,7,13 */
693{ 2412, 2437, 2462, 2442, 2472 };
694static const uint16_t rcl4[] =		/* 5 FCC channel: 149, 153, 161, 165 */
695{ 5745, 5765, 5785, 5805, 5825 };
696static const uint16_t rcl7[] =		/* 11 ETSI channel: 100,104,108,112,116,120,124,128,132,136,140 */
697{ 5500, 5520, 5540, 5560, 5580, 5600, 5620, 5640, 5660, 5680, 5700 };
698static const uint16_t rcl8[] =		/* 2.4Ghz ch: 2,3,4,5,8,9,10,12 */
699{ 2417, 2422, 2427, 2432, 2447, 2452, 2457, 2467 };
700static const uint16_t rcl9[] =		/* 2.4Ghz ch: 14 */
701{ 2484 };
702static const uint16_t rcl10[] =	/* Added Korean channels 2312-2372 */
703{ 2312, 2317, 2322, 2327, 2332, 2337, 2342, 2347, 2352, 2357, 2362, 2367, 2372 };
704static const uint16_t rcl11[] =	/* Added Japan channels in 4.9/5.0 spectrum */
705{ 5040, 5060, 5080, 4920, 4940, 4960, 4980 };
706#ifdef ATH_TURBO_SCAN
707static const uint16_t rcl5[] =		/* 3 static turbo channels */
708{ 5210, 5250, 5290 };
709static const uint16_t rcl6[] =		/* 2 static turbo channels */
710{ 5760, 5800 };
711static const uint16_t rcl6x[] =	/* 4 FCC3 turbo channels */
712{ 5540, 5580, 5620, 5660 };
713static const uint16_t rcl12[] =	/* 2.4Ghz Turbo channel 6 */
714{ 2437 };
715static const uint16_t rcl13[] =	/* dynamic Turbo channels */
716{ 5200, 5240, 5280, 5765, 5805 };
717#endif /* ATH_TURBO_SCAN */
718
719#define	X(a)	.count = sizeof(a)/sizeof(a[0]), .list = a
720
721static const struct scanlist staScanTable[] = {
722	{ IEEE80211_MODE_11B,   	X(rcl3) },
723	{ IEEE80211_MODE_11A,   	X(rcl1) },
724	{ IEEE80211_MODE_11A,   	X(rcl2) },
725	{ IEEE80211_MODE_11B,   	X(rcl8) },
726	{ IEEE80211_MODE_11B,   	X(rcl9) },
727	{ IEEE80211_MODE_11A,   	X(rcl4) },
728#ifdef ATH_TURBO_SCAN
729	{ IEEE80211_MODE_STURBO_A,	X(rcl5) },
730	{ IEEE80211_MODE_STURBO_A,	X(rcl6) },
731	{ IEEE80211_MODE_TURBO_A,	X(rcl6x) },
732	{ IEEE80211_MODE_TURBO_A,	X(rcl13) },
733#endif /* ATH_TURBO_SCAN */
734	{ IEEE80211_MODE_11A,		X(rcl7) },
735	{ IEEE80211_MODE_11B,		X(rcl10) },
736	{ IEEE80211_MODE_11A,		X(rcl11) },
737#ifdef ATH_TURBO_SCAN
738	{ IEEE80211_MODE_TURBO_G,	X(rcl12) },
739#endif /* ATH_TURBO_SCAN */
740	{ .list = NULL }
741};
742
743/*
744 * Start a station-mode scan by populating the channel list.
745 */
746static int
747sta_start(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
748{
749	struct sta_table *st = ss->ss_priv;
750
751	makescanlist(ss, vap, staScanTable);
752
753	if (ss->ss_mindwell == 0)
754		ss->ss_mindwell = msecs_to_ticks(20);	/* 20ms */
755	if (ss->ss_maxdwell == 0)
756		ss->ss_maxdwell = msecs_to_ticks(200);	/* 200ms */
757
758	st->st_scangen++;
759	st->st_newscan = 1;
760
761	return 0;
762}
763
764/*
765 * Restart a scan, typically a bg scan but can
766 * also be a fg scan that came up empty.
767 */
768static int
769sta_restart(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
770{
771	struct sta_table *st = ss->ss_priv;
772
773	st->st_newscan = 1;
774	return 0;
775}
776
777/*
778 * Cancel an ongoing scan.
779 */
780static int
781sta_cancel(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
782{
783	return 0;
784}
785
786/*
787 * Demote any supplied 11g channel to 11b.  There should
788 * always be an 11b channel but we check anyway...
789 */
790static struct ieee80211_channel *
791demote11b(struct ieee80211vap *vap, struct ieee80211_channel *chan)
792{
793	struct ieee80211_channel *c;
794
795	if (IEEE80211_IS_CHAN_ANYG(chan) &&
796	    vap->iv_des_mode == IEEE80211_MODE_AUTO) {
797		c = ieee80211_find_channel(vap->iv_ic, chan->ic_freq,
798		    (chan->ic_flags &~ (IEEE80211_CHAN_PUREG | IEEE80211_CHAN_G)) |
799		    IEEE80211_CHAN_B);
800		if (c != NULL)
801			chan = c;
802	}
803	return chan;
804}
805
806static int
807maxrate(const struct ieee80211_scan_entry *se)
808{
809	const struct ieee80211_ie_htcap *htcap =
810	    (const struct ieee80211_ie_htcap *) se->se_ies.htcap_ie;
811	int rmax, r, i, txstream;
812	uint16_t caps;
813	uint8_t txparams;
814
815	rmax = 0;
816	if (htcap != NULL) {
817		/*
818		 * HT station; inspect supported MCS and then adjust
819		 * rate by channel width.
820		 */
821		txparams = htcap->hc_mcsset[12];
822		if (txparams & 0x3) {
823			/*
824			 * TX MCS parameters defined and not equal to RX,
825			 * extract the number of spartial streams and
826			 * map it to the highest MCS rate.
827			 */
828			txstream = ((txparams & 0xc) >> 2) + 1;
829			i = txstream * 8 - 1;
830		} else
831			for (i = 31; i >= 0 && isclr(htcap->hc_mcsset, i); i--);
832		if (i >= 0) {
833			caps = le16dec(&htcap->hc_cap);
834			if ((caps & IEEE80211_HTCAP_CHWIDTH40) &&
835			    (caps & IEEE80211_HTCAP_SHORTGI40))
836				rmax = ieee80211_htrates[i].ht40_rate_400ns;
837			else if (caps & IEEE80211_HTCAP_CHWIDTH40)
838				rmax = ieee80211_htrates[i].ht40_rate_800ns;
839			else if (caps & IEEE80211_HTCAP_SHORTGI20)
840				rmax = ieee80211_htrates[i].ht20_rate_400ns;
841			else
842				rmax = ieee80211_htrates[i].ht20_rate_800ns;
843		}
844	}
845	for (i = 0; i < se->se_rates[1]; i++) {
846		r = se->se_rates[2+i] & IEEE80211_RATE_VAL;
847		if (r > rmax)
848			rmax = r;
849	}
850	for (i = 0; i < se->se_xrates[1]; i++) {
851		r = se->se_xrates[2+i] & IEEE80211_RATE_VAL;
852		if (r > rmax)
853			rmax = r;
854	}
855	return rmax;
856}
857
858/*
859 * Compare the capabilities of two entries and decide which is
860 * more desirable (return >0 if a is considered better).  Note
861 * that we assume compatibility/usability has already been checked
862 * so we don't need to (e.g. validate whether privacy is supported).
863 * Used to select the best scan candidate for association in a BSS.
864 *
865 * TODO: should we take 11n, 11ac into account when selecting the
866 * best?  Right now it just compares frequency band and RSSI.
867 */
868static int
869sta_compare(const struct sta_entry *a, const struct sta_entry *b)
870{
871#define	PREFER(_a,_b,_what) do {			\
872	if (((_a) ^ (_b)) & (_what))			\
873		return ((_a) & (_what)) ? 1 : -1;	\
874} while (0)
875	int maxa, maxb;
876	int8_t rssia, rssib;
877	int weight;
878
879	/* privacy support */
880	PREFER(a->base.se_capinfo, b->base.se_capinfo,
881		IEEE80211_CAPINFO_PRIVACY);
882
883	/* compare count of previous failures */
884	weight = b->se_fails - a->se_fails;
885	if (abs(weight) > 1)
886		return weight;
887
888	/*
889	 * Compare rssi.  If the two are considered equivalent
890	 * then fallback to other criteria.  We threshold the
891	 * comparisons to avoid selecting an ap purely by rssi
892	 * when both values may be good but one ap is otherwise
893	 * more desirable (e.g. an 11b-only ap with stronger
894	 * signal than an 11g ap).
895	 */
896	rssia = MIN(a->base.se_rssi, STA_RSSI_MAX);
897	rssib = MIN(b->base.se_rssi, STA_RSSI_MAX);
898	if (abs(rssib - rssia) < 5) {
899		/* best/max rate preferred if signal level close enough XXX */
900		maxa = maxrate(&a->base);
901		maxb = maxrate(&b->base);
902		if (maxa != maxb)
903			return maxa - maxb;
904		/* XXX use freq for channel preference */
905		/* for now just prefer 5Ghz band to all other bands */
906		PREFER(IEEE80211_IS_CHAN_5GHZ(a->base.se_chan),
907		       IEEE80211_IS_CHAN_5GHZ(b->base.se_chan), 1);
908	}
909	/* all things being equal, use signal level */
910	return a->base.se_rssi - b->base.se_rssi;
911#undef PREFER
912}
913
914/*
915 * Check rate set suitability and return the best supported rate.
916 * XXX inspect MCS for HT
917 */
918static int
919check_rate(struct ieee80211vap *vap, const struct ieee80211_channel *chan,
920    const struct ieee80211_scan_entry *se)
921{
922	const struct ieee80211_rateset *srs;
923	int i, j, nrs, r, okrate, badrate, fixedrate, ucastrate;
924	const uint8_t *rs;
925
926	okrate = badrate = 0;
927
928	srs = ieee80211_get_suprates(vap->iv_ic, chan);
929	nrs = se->se_rates[1];
930	rs = se->se_rates+2;
931	/* XXX MCS */
932	ucastrate = vap->iv_txparms[ieee80211_chan2mode(chan)].ucastrate;
933	fixedrate = IEEE80211_FIXED_RATE_NONE;
934again:
935	for (i = 0; i < nrs; i++) {
936		r = IEEE80211_RV(rs[i]);
937		badrate = r;
938		/*
939		 * Check any fixed rate is included.
940		 */
941		if (r == ucastrate)
942			fixedrate = r;
943		/*
944		 * Check against our supported rates.
945		 */
946		for (j = 0; j < srs->rs_nrates; j++)
947			if (r == IEEE80211_RV(srs->rs_rates[j])) {
948				if (r > okrate)		/* NB: track max */
949					okrate = r;
950				break;
951			}
952
953		if (j == srs->rs_nrates && (rs[i] & IEEE80211_RATE_BASIC)) {
954			/*
955			 * Don't try joining a BSS, if we don't support
956			 * one of its basic rates.
957			 */
958			okrate = 0;
959			goto back;
960		}
961	}
962	if (rs == se->se_rates+2) {
963		/* scan xrates too; sort of an algol68-style for loop */
964		nrs = se->se_xrates[1];
965		rs = se->se_xrates+2;
966		goto again;
967	}
968
969back:
970	if (okrate == 0 || ucastrate != fixedrate)
971		return badrate | IEEE80211_RATE_BASIC;
972	else
973		return IEEE80211_RV(okrate);
974}
975
976static __inline int
977match_id(const uint8_t *ie, const uint8_t *val, int len)
978{
979	return (ie[1] == len && memcmp(ie+2, val, len) == 0);
980}
981
982static int
983match_ssid(const uint8_t *ie,
984	int nssid, const struct ieee80211_scan_ssid ssids[])
985{
986	int i;
987
988	for (i = 0; i < nssid; i++) {
989		if (match_id(ie, ssids[i].ssid, ssids[i].len))
990			return 1;
991	}
992	return 0;
993}
994
995#ifdef IEEE80211_SUPPORT_TDMA
996static int
997tdma_isfull(const struct ieee80211_tdma_param *tdma)
998{
999	int slot, slotcnt;
1000
1001	slotcnt = tdma->tdma_slotcnt;
1002	for (slot = slotcnt-1; slot >= 0; slot--)
1003		if (isclr(tdma->tdma_inuse, slot))
1004			return 0;
1005	return 1;
1006}
1007#endif /* IEEE80211_SUPPORT_TDMA */
1008
1009/*
1010 * Test a scan candidate for suitability/compatibility.
1011 */
1012static int
1013match_bss(struct ieee80211vap *vap,
1014	const struct ieee80211_scan_state *ss, struct sta_entry *se0,
1015	int debug)
1016{
1017	struct ieee80211com *ic = vap->iv_ic;
1018	struct ieee80211_scan_entry *se = &se0->base;
1019        uint8_t rate;
1020        int fail;
1021
1022	fail = 0;
1023	if (isclr(ic->ic_chan_active, ieee80211_chan2ieee(ic, se->se_chan)))
1024		fail |= MATCH_CHANNEL;
1025	/*
1026	 * NB: normally the desired mode is used to construct
1027	 * the channel list, but it's possible for the scan
1028	 * cache to include entries for stations outside this
1029	 * list so we check the desired mode here to weed them
1030	 * out.
1031	 */
1032	if (vap->iv_des_mode != IEEE80211_MODE_AUTO &&
1033	    (se->se_chan->ic_flags & IEEE80211_CHAN_ALLTURBO) !=
1034	    chanflags[vap->iv_des_mode])
1035		fail |= MATCH_CHANNEL;
1036	if (vap->iv_opmode == IEEE80211_M_IBSS) {
1037		if ((se->se_capinfo & IEEE80211_CAPINFO_IBSS) == 0)
1038			fail |= MATCH_CAPINFO;
1039#ifdef IEEE80211_SUPPORT_TDMA
1040	} else if (vap->iv_opmode == IEEE80211_M_AHDEMO) {
1041		/*
1042		 * Adhoc demo network setup shouldn't really be scanning
1043		 * but just in case skip stations operating in IBSS or
1044		 * BSS mode.
1045		 */
1046		if (se->se_capinfo & (IEEE80211_CAPINFO_IBSS|IEEE80211_CAPINFO_ESS))
1047			fail |= MATCH_CAPINFO;
1048		/*
1049		 * TDMA operation cannot coexist with a normal 802.11 network;
1050		 * skip if IBSS or ESS capabilities are marked and require
1051		 * the beacon have a TDMA ie present.
1052		 */
1053		if (vap->iv_caps & IEEE80211_C_TDMA) {
1054			const struct ieee80211_tdma_param *tdma =
1055			    (const struct ieee80211_tdma_param *)se->se_ies.tdma_ie;
1056			const struct ieee80211_tdma_state *ts = vap->iv_tdma;
1057
1058			if (tdma == NULL)
1059				fail |= MATCH_TDMA_NOIE;
1060			else if (tdma->tdma_version != ts->tdma_version)
1061				fail |= MATCH_TDMA_VERSION;
1062			else if (tdma->tdma_slot != 0)
1063				fail |= MATCH_TDMA_NOTMASTER;
1064			else if (tdma_isfull(tdma))
1065				fail |= MATCH_TDMA_NOSLOT;
1066#if 0
1067			else if (ieee80211_local_address(se->se_macaddr))
1068				fail |= MATCH_TDMA_LOCAL;
1069#endif
1070		}
1071#endif /* IEEE80211_SUPPORT_TDMA */
1072#ifdef IEEE80211_SUPPORT_MESH
1073	} else if (vap->iv_opmode == IEEE80211_M_MBSS) {
1074		const struct ieee80211_mesh_state *ms = vap->iv_mesh;
1075		/*
1076		 * Mesh nodes have IBSS & ESS bits in capinfo turned off
1077		 * and two special ie's that must be present.
1078		 */
1079		if (se->se_capinfo & (IEEE80211_CAPINFO_IBSS|IEEE80211_CAPINFO_ESS))
1080			fail |= MATCH_CAPINFO;
1081		else if (se->se_meshid[0] != IEEE80211_ELEMID_MESHID)
1082			fail |= MATCH_MESH_NOID;
1083		else if (ms->ms_idlen != 0 &&
1084		    match_id(se->se_meshid, ms->ms_id, ms->ms_idlen))
1085			fail |= MATCH_MESHID;
1086#endif
1087	} else {
1088		if ((se->se_capinfo & IEEE80211_CAPINFO_ESS) == 0)
1089			fail |= MATCH_CAPINFO;
1090		/*
1091		 * If 11d is enabled and we're attempting to join a bss
1092		 * that advertises it's country code then compare our
1093		 * current settings to what we fetched from the country ie.
1094		 * If our country code is unspecified or different then do
1095		 * not attempt to join the bss.  We should have already
1096		 * dispatched an event to user space that identifies the
1097		 * new country code so our regdomain config should match.
1098		 */
1099		if ((IEEE80211_IS_CHAN_11D(se->se_chan) ||
1100		    (vap->iv_flags_ext & IEEE80211_FEXT_DOTD)) &&
1101		    se->se_cc[0] != 0 &&
1102		    (ic->ic_regdomain.country == CTRY_DEFAULT ||
1103		     !isocmp(se->se_cc, ic->ic_regdomain.isocc)))
1104			fail |= MATCH_CC;
1105	}
1106	if (vap->iv_flags & IEEE80211_F_PRIVACY) {
1107		if ((se->se_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0)
1108			fail |= MATCH_PRIVACY;
1109	} else {
1110		/* XXX does this mean privacy is supported or required? */
1111		if (se->se_capinfo & IEEE80211_CAPINFO_PRIVACY)
1112			fail |= MATCH_PRIVACY;
1113	}
1114	se0->se_flags &= ~STA_DEMOTE11B;
1115	rate = check_rate(vap, se->se_chan, se);
1116	if (rate & IEEE80211_RATE_BASIC) {
1117		fail |= MATCH_RATE;
1118		/*
1119		 * An 11b-only ap will give a rate mismatch if there is an
1120		 * OFDM fixed tx rate for 11g.  Try downgrading the channel
1121		 * in the scan list to 11b and retry the rate check.
1122		 */
1123		if (IEEE80211_IS_CHAN_ANYG(se->se_chan)) {
1124			rate = check_rate(vap, demote11b(vap, se->se_chan), se);
1125			if ((rate & IEEE80211_RATE_BASIC) == 0) {
1126				fail &= ~MATCH_RATE;
1127				se0->se_flags |= STA_DEMOTE11B;
1128			}
1129		}
1130	} else if (rate < 2*24) {
1131		/*
1132		 * This is an 11b-only ap.  Check the desired mode in
1133		 * case that needs to be honored (mode 11g filters out
1134		 * 11b-only ap's).  Otherwise force any 11g channel used
1135		 * in scanning to be demoted.
1136		 *
1137		 * NB: we cheat a bit here by looking at the max rate;
1138		 *     we could/should check the rates.
1139		 */
1140		if (!(vap->iv_des_mode == IEEE80211_MODE_AUTO ||
1141		      vap->iv_des_mode == IEEE80211_MODE_11B))
1142			fail |= MATCH_RATE;
1143		else
1144			se0->se_flags |= STA_DEMOTE11B;
1145	}
1146	if (ss->ss_nssid != 0 &&
1147	    !match_ssid(se->se_ssid, ss->ss_nssid, ss->ss_ssid))
1148		fail |= MATCH_SSID;
1149	if ((vap->iv_flags & IEEE80211_F_DESBSSID) &&
1150	    !IEEE80211_ADDR_EQ(vap->iv_des_bssid, se->se_bssid))
1151		fail |= MATCH_BSSID;
1152	if (se0->se_fails >= STA_FAILS_MAX)
1153		fail |= MATCH_FAILS;
1154	if (se0->se_notseen >= STA_PURGE_SCANS)
1155		fail |= MATCH_NOTSEEN;
1156	if (se->se_rssi < STA_RSSI_MIN)
1157		fail |= MATCH_RSSI;
1158#ifdef IEEE80211_DEBUG
1159	if (ieee80211_msg(vap, debug)) {
1160		printf(" %c %s",
1161		    fail & MATCH_FAILS ? '=' :
1162		    fail & MATCH_NOTSEEN ? '^' :
1163		    fail & MATCH_CC ? '$' :
1164#ifdef IEEE80211_SUPPORT_TDMA
1165		    fail & MATCH_TDMA_NOIE ? '&' :
1166		    fail & MATCH_TDMA_VERSION ? 'v' :
1167		    fail & MATCH_TDMA_NOTMASTER ? 's' :
1168		    fail & MATCH_TDMA_NOSLOT ? 'f' :
1169		    fail & MATCH_TDMA_LOCAL ? 'l' :
1170#endif
1171		    fail & MATCH_MESH_NOID ? 'm' :
1172		    fail ? '-' : '+', ether_sprintf(se->se_macaddr));
1173		printf(" %s%c", ether_sprintf(se->se_bssid),
1174		    fail & MATCH_BSSID ? '!' : ' ');
1175		printf(" %3d%c", ieee80211_chan2ieee(ic, se->se_chan),
1176			fail & MATCH_CHANNEL ? '!' : ' ');
1177		printf(" %+4d%c", se->se_rssi, fail & MATCH_RSSI ? '!' : ' ');
1178		printf(" %2dM%c", (rate & IEEE80211_RATE_VAL) / 2,
1179		    fail & MATCH_RATE ? '!' : ' ');
1180		printf(" %4s%c",
1181		    (se->se_capinfo & IEEE80211_CAPINFO_ESS) ? "ess" :
1182		    (se->se_capinfo & IEEE80211_CAPINFO_IBSS) ? "ibss" : "",
1183		    fail & MATCH_CAPINFO ? '!' : ' ');
1184		printf(" %3s%c ",
1185		    (se->se_capinfo & IEEE80211_CAPINFO_PRIVACY) ?
1186		    "wep" : "no",
1187		    fail & MATCH_PRIVACY ? '!' : ' ');
1188		ieee80211_print_essid(se->se_ssid+2, se->se_ssid[1]);
1189		printf("%s\n", fail & (MATCH_SSID | MATCH_MESHID) ? "!" : "");
1190	}
1191#endif
1192	return fail;
1193}
1194
1195static void
1196sta_update_notseen(struct sta_table *st)
1197{
1198	struct sta_entry *se;
1199
1200	IEEE80211_SCAN_TABLE_LOCK(st);
1201	TAILQ_FOREACH(se, &st->st_entry, se_list) {
1202		/*
1203		 * If seen the reset and don't bump the count;
1204		 * otherwise bump the ``not seen'' count.  Note
1205		 * that this insures that stations for which we
1206		 * see frames while not scanning but not during
1207		 * this scan will not be penalized.
1208		 */
1209		if (se->se_seen)
1210			se->se_seen = 0;
1211		else
1212			se->se_notseen++;
1213	}
1214	IEEE80211_SCAN_TABLE_UNLOCK(st);
1215}
1216
1217static void
1218sta_dec_fails(struct sta_table *st)
1219{
1220	struct sta_entry *se;
1221
1222	IEEE80211_SCAN_TABLE_LOCK(st);
1223	TAILQ_FOREACH(se, &st->st_entry, se_list)
1224		if (se->se_fails)
1225			se->se_fails--;
1226	IEEE80211_SCAN_TABLE_UNLOCK(st);
1227}
1228
1229static struct sta_entry *
1230select_bss(struct ieee80211_scan_state *ss, struct ieee80211vap *vap, int debug)
1231{
1232	struct sta_table *st = ss->ss_priv;
1233	struct sta_entry *se, *selbs = NULL;
1234
1235	IEEE80211_DPRINTF(vap, debug, " %s\n",
1236	    "macaddr          bssid         chan  rssi  rate flag  wep  essid");
1237	IEEE80211_SCAN_TABLE_LOCK(st);
1238	TAILQ_FOREACH(se, &st->st_entry, se_list) {
1239		ieee80211_ies_expand(&se->base.se_ies);
1240		if (match_bss(vap, ss, se, debug) == 0) {
1241			if (selbs == NULL)
1242				selbs = se;
1243			else if (sta_compare(se, selbs) > 0)
1244				selbs = se;
1245		}
1246	}
1247	IEEE80211_SCAN_TABLE_UNLOCK(st);
1248
1249	return selbs;
1250}
1251
1252/*
1253 * Pick an ap or ibss network to join or find a channel
1254 * to use to start an ibss network.
1255 */
1256static int
1257sta_pick_bss(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
1258{
1259	struct sta_table *st = ss->ss_priv;
1260	struct sta_entry *selbs;
1261	struct ieee80211_channel *chan;
1262
1263	KASSERT(vap->iv_opmode == IEEE80211_M_STA,
1264		("wrong mode %u", vap->iv_opmode));
1265
1266	if (st->st_newscan) {
1267		sta_update_notseen(st);
1268		st->st_newscan = 0;
1269	}
1270	if (ss->ss_flags & IEEE80211_SCAN_NOPICK) {
1271		/*
1272		 * Manual/background scan, don't select+join the
1273		 * bss, just return.  The scanning framework will
1274		 * handle notification that this has completed.
1275		 */
1276		ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
1277		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1278		    "%s: nopick; return 1\n", __func__);
1279		return 1;
1280	}
1281	/*
1282	 * Automatic sequencing; look for a candidate and
1283	 * if found join the network.
1284	 */
1285	/* NB: unlocked read should be ok */
1286	if (TAILQ_FIRST(&st->st_entry) == NULL) {
1287		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1288			"%s: no scan candidate, join=%d, return 0\n",
1289			__func__,
1290			!! (ss->ss_flags & IEEE80211_SCAN_NOJOIN));
1291		if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
1292			return 0;
1293notfound:
1294		/*
1295		 * If nothing suitable was found decrement
1296		 * the failure counts so entries will be
1297		 * reconsidered the next time around.  We
1298		 * really want to do this only for sta's
1299		 * where we've previously had some success.
1300		 */
1301		sta_dec_fails(st);
1302		st->st_newscan = 1;
1303		return 0;			/* restart scan */
1304	}
1305	selbs = select_bss(ss, vap, IEEE80211_MSG_SCAN);
1306	if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
1307		return (selbs != NULL);
1308	if (selbs == NULL)
1309		goto notfound;
1310	chan = selbs->base.se_chan;
1311	if (selbs->se_flags & STA_DEMOTE11B)
1312		chan = demote11b(vap, chan);
1313	if (!ieee80211_sta_join(vap, chan, &selbs->base))
1314		goto notfound;
1315	IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1316	    "%s: terminate scan; return 1\n", __func__);
1317	return 1;				/* terminate scan */
1318}
1319
1320/*
1321 * Lookup an entry in the scan cache.  We assume we're
1322 * called from the bottom half or such that we don't need
1323 * to block the bottom half so that it's safe to return
1324 * a reference to an entry w/o holding the lock on the table.
1325 */
1326static struct sta_entry *
1327sta_lookup(struct sta_table *st, const uint8_t macaddr[IEEE80211_ADDR_LEN])
1328{
1329	struct sta_entry *se;
1330	int hash = STA_HASH(macaddr);
1331
1332	IEEE80211_SCAN_TABLE_LOCK(st);
1333	LIST_FOREACH(se, &st->st_hash[hash], se_hash)
1334		if (IEEE80211_ADDR_EQ(se->base.se_macaddr, macaddr))
1335			break;
1336	IEEE80211_SCAN_TABLE_UNLOCK(st);
1337
1338	return se;		/* NB: unlocked */
1339}
1340
1341static void
1342sta_roam_check(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
1343{
1344	struct ieee80211com *ic = vap->iv_ic;
1345	struct ieee80211_node *ni = vap->iv_bss;
1346	struct sta_table *st = ss->ss_priv;
1347	enum ieee80211_phymode mode;
1348	struct sta_entry *se, *selbs;
1349	uint8_t roamRate, curRate, ucastRate;
1350	int8_t roamRssi, curRssi;
1351
1352	se = sta_lookup(st, ni->ni_macaddr);
1353	if (se == NULL) {
1354		/* XXX something is wrong */
1355		return;
1356	}
1357
1358	mode = ieee80211_chan2mode(ic->ic_bsschan);
1359	roamRate = vap->iv_roamparms[mode].rate;
1360	roamRssi = vap->iv_roamparms[mode].rssi;
1361	KASSERT(roamRate != 0 && roamRssi != 0, ("iv_roamparms are not"
1362	    "initialized for %s mode!", ieee80211_phymode_name[mode]));
1363
1364	ucastRate = vap->iv_txparms[mode].ucastrate;
1365	/* NB: the most up to date rssi is in the node, not the scan cache */
1366	curRssi = ic->ic_node_getrssi(ni);
1367	if (ucastRate == IEEE80211_FIXED_RATE_NONE) {
1368		curRate = ni->ni_txrate;
1369		IEEE80211_DPRINTF(vap, IEEE80211_MSG_ROAM,
1370		    "%s: currssi %d currate %u roamrssi %d roamrate %u\n",
1371		    __func__, curRssi, curRate, roamRssi, roamRate);
1372	} else {
1373		curRate = roamRate;	/* NB: insure compare below fails */
1374		IEEE80211_DPRINTF(vap, IEEE80211_MSG_ROAM,
1375		    "%s: currssi %d roamrssi %d\n", __func__, curRssi, roamRssi);
1376	}
1377	/*
1378	 * Check if a new ap should be used and switch.
1379	 * XXX deauth current ap
1380	 */
1381	if (curRate < roamRate || curRssi < roamRssi) {
1382		if (ieee80211_time_after(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
1383			/*
1384			 * Scan cache contents are too old; force a scan now
1385			 * if possible so we have current state to make a
1386			 * decision with.  We don't kick off a bg scan if
1387			 * we're using dynamic turbo and boosted or if the
1388			 * channel is busy.
1389			 * XXX force immediate switch on scan complete
1390			 */
1391			if (!IEEE80211_IS_CHAN_DTURBO(ic->ic_curchan) &&
1392			    ((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) ||
1393			     ieee80211_time_after(ticks, ic->ic_lastdata + vap->iv_bgscanidle)))
1394				ieee80211_bg_scan(vap, 0);
1395			return;
1396		}
1397		se->base.se_rssi = curRssi;
1398		selbs = select_bss(ss, vap, IEEE80211_MSG_ROAM);
1399		if (selbs != NULL && selbs != se) {
1400			struct ieee80211_channel *chan;
1401
1402			IEEE80211_DPRINTF(vap,
1403			    IEEE80211_MSG_ROAM | IEEE80211_MSG_DEBUG,
1404			    "%s: ROAM: curRate %u, roamRate %u, "
1405			    "curRssi %d, roamRssi %d\n", __func__,
1406			    curRate, roamRate, curRssi, roamRssi);
1407
1408			chan = selbs->base.se_chan;
1409			if (selbs->se_flags & STA_DEMOTE11B)
1410				chan = demote11b(vap, chan);
1411			(void) ieee80211_sta_join(vap, chan, &selbs->base);
1412		}
1413	}
1414}
1415
1416/*
1417 * Age entries in the scan cache.
1418 * XXX also do roaming since it's convenient
1419 */
1420static void
1421sta_age(struct ieee80211_scan_state *ss)
1422{
1423	struct ieee80211vap *vap = ss->ss_vap;
1424
1425	adhoc_age(ss);
1426	/*
1427	 * If rate control is enabled check periodically to see if
1428	 * we should roam from our current connection to one that
1429	 * might be better.  This only applies when we're operating
1430	 * in sta mode and automatic roaming is set.
1431	 * XXX defer if busy
1432	 * XXX repeater station
1433	 * XXX do when !bgscan?
1434	 */
1435	KASSERT(vap->iv_opmode == IEEE80211_M_STA,
1436		("wrong mode %u", vap->iv_opmode));
1437	if (vap->iv_roaming == IEEE80211_ROAMING_AUTO &&
1438	    (vap->iv_flags & IEEE80211_F_BGSCAN) &&
1439	    vap->iv_state >= IEEE80211_S_RUN)
1440		/* XXX vap is implicit */
1441		sta_roam_check(ss, vap);
1442}
1443
1444/*
1445 * Iterate over the entries in the scan cache, invoking
1446 * the callback function on each one.
1447 */
1448static void
1449sta_iterate(struct ieee80211_scan_state *ss,
1450	ieee80211_scan_iter_func *f, void *arg)
1451{
1452	struct sta_table *st = ss->ss_priv;
1453	struct sta_entry *se;
1454	u_int gen;
1455
1456	IEEE80211_SCAN_ITER_LOCK(st);
1457	gen = st->st_scaniter++;
1458restart:
1459	IEEE80211_SCAN_TABLE_LOCK(st);
1460	TAILQ_FOREACH(se, &st->st_entry, se_list) {
1461		if (se->se_scangen != gen) {
1462			se->se_scangen = gen;
1463			/* update public state */
1464			se->base.se_age = ticks - se->se_lastupdate;
1465			IEEE80211_SCAN_TABLE_UNLOCK(st);
1466			(*f)(arg, &se->base);
1467			goto restart;
1468		}
1469	}
1470	IEEE80211_SCAN_TABLE_UNLOCK(st);
1471
1472	IEEE80211_SCAN_ITER_UNLOCK(st);
1473}
1474
1475static void
1476sta_assoc_fail(struct ieee80211_scan_state *ss,
1477	const uint8_t macaddr[IEEE80211_ADDR_LEN], int reason)
1478{
1479	struct sta_table *st = ss->ss_priv;
1480	struct sta_entry *se;
1481
1482	se = sta_lookup(st, macaddr);
1483	if (se != NULL) {
1484		se->se_fails++;
1485		se->se_lastfail = ticks;
1486		IEEE80211_NOTE_MAC(ss->ss_vap, IEEE80211_MSG_SCAN,
1487		    macaddr, "%s: reason %u fails %u",
1488		    __func__, reason, se->se_fails);
1489	}
1490}
1491
1492static void
1493sta_assoc_success(struct ieee80211_scan_state *ss,
1494	const uint8_t macaddr[IEEE80211_ADDR_LEN])
1495{
1496	struct sta_table *st = ss->ss_priv;
1497	struct sta_entry *se;
1498
1499	se = sta_lookup(st, macaddr);
1500	if (se != NULL) {
1501#if 0
1502		se->se_fails = 0;
1503		IEEE80211_NOTE_MAC(ss->ss_vap, IEEE80211_MSG_SCAN,
1504		    macaddr, "%s: fails %u",
1505		    __func__, se->se_fails);
1506#endif
1507		se->se_lastassoc = ticks;
1508	}
1509}
1510
1511static const struct ieee80211_scanner sta_default = {
1512	.scan_name		= "default",
1513	.scan_attach		= sta_attach,
1514	.scan_detach		= sta_detach,
1515	.scan_start		= sta_start,
1516	.scan_restart		= sta_restart,
1517	.scan_cancel		= sta_cancel,
1518	.scan_end		= sta_pick_bss,
1519	.scan_flush		= sta_flush,
1520	.scan_add		= sta_add,
1521	.scan_age		= sta_age,
1522	.scan_iterate		= sta_iterate,
1523	.scan_assoc_fail	= sta_assoc_fail,
1524	.scan_assoc_success	= sta_assoc_success,
1525};
1526IEEE80211_SCANNER_ALG(sta, IEEE80211_M_STA, sta_default);
1527
1528/*
1529 * Adhoc mode-specific support.
1530 */
1531
1532static const uint16_t adhocWorld[] =		/* 36, 40, 44, 48 */
1533{ 5180, 5200, 5220, 5240 };
1534static const uint16_t adhocFcc3[] =		/* 36, 40, 44, 48 145, 149, 153, 157, 161, 165 */
1535{ 5180, 5200, 5220, 5240, 5725, 5745, 5765, 5785, 5805, 5825 };
1536static const uint16_t adhocMkk[] =		/* 34, 38, 42, 46 */
1537{ 5170, 5190, 5210, 5230 };
1538static const uint16_t adhoc11b[] =		/* 10, 11 */
1539{ 2457, 2462 };
1540
1541static const struct scanlist adhocScanTable[] = {
1542	{ IEEE80211_MODE_11B,   	X(adhoc11b) },
1543	{ IEEE80211_MODE_11A,   	X(adhocWorld) },
1544	{ IEEE80211_MODE_11A,   	X(adhocFcc3) },
1545	{ IEEE80211_MODE_11B,   	X(adhocMkk) },
1546	{ .list = NULL }
1547};
1548#undef X
1549
1550/*
1551 * Start an adhoc-mode scan by populating the channel list.
1552 */
1553static int
1554adhoc_start(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
1555{
1556	struct sta_table *st = ss->ss_priv;
1557
1558	makescanlist(ss, vap, adhocScanTable);
1559
1560	if (ss->ss_mindwell == 0)
1561		ss->ss_mindwell = msecs_to_ticks(200);	/* 200ms */
1562	if (ss->ss_maxdwell == 0)
1563		ss->ss_maxdwell = msecs_to_ticks(200);	/* 200ms */
1564
1565	st->st_scangen++;
1566	st->st_newscan = 1;
1567
1568	return 0;
1569}
1570
1571/*
1572 * Select a channel to start an adhoc network on.
1573 * The channel list was populated with appropriate
1574 * channels so select one that looks least occupied.
1575 */
1576static struct ieee80211_channel *
1577adhoc_pick_channel(struct ieee80211_scan_state *ss, int flags)
1578{
1579	struct sta_table *st = ss->ss_priv;
1580	struct sta_entry *se;
1581	struct ieee80211_channel *c, *bestchan;
1582	int i, bestrssi, maxrssi;
1583
1584	bestchan = NULL;
1585	bestrssi = -1;
1586
1587	IEEE80211_SCAN_TABLE_LOCK(st);
1588	for (i = 0; i < ss->ss_last; i++) {
1589		c = ss->ss_chans[i];
1590		/* never consider a channel with radar */
1591		if (IEEE80211_IS_CHAN_RADAR(c))
1592			continue;
1593		/* skip channels disallowed by regulatory settings */
1594		if (IEEE80211_IS_CHAN_NOADHOC(c))
1595			continue;
1596		/* check channel attributes for band compatibility */
1597		if (flags != 0 && (c->ic_flags & flags) != flags)
1598			continue;
1599		maxrssi = 0;
1600		TAILQ_FOREACH(se, &st->st_entry, se_list) {
1601			if (se->base.se_chan != c)
1602				continue;
1603			if (se->base.se_rssi > maxrssi)
1604				maxrssi = se->base.se_rssi;
1605		}
1606		if (bestchan == NULL || maxrssi < bestrssi)
1607			bestchan = c;
1608	}
1609	IEEE80211_SCAN_TABLE_UNLOCK(st);
1610
1611	return bestchan;
1612}
1613
1614/*
1615 * Pick an ibss network to join or find a channel
1616 * to use to start an ibss network.
1617 */
1618static int
1619adhoc_pick_bss(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
1620{
1621	struct sta_table *st = ss->ss_priv;
1622	struct sta_entry *selbs;
1623	struct ieee80211_channel *chan;
1624	struct ieee80211com *ic = vap->iv_ic;
1625
1626	KASSERT(vap->iv_opmode == IEEE80211_M_IBSS ||
1627		vap->iv_opmode == IEEE80211_M_AHDEMO ||
1628		vap->iv_opmode == IEEE80211_M_MBSS,
1629		("wrong opmode %u", vap->iv_opmode));
1630
1631	if (st->st_newscan) {
1632		sta_update_notseen(st);
1633		st->st_newscan = 0;
1634	}
1635	if (ss->ss_flags & IEEE80211_SCAN_NOPICK) {
1636		/*
1637		 * Manual/background scan, don't select+join the
1638		 * bss, just return.  The scanning framework will
1639		 * handle notification that this has completed.
1640		 */
1641		ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
1642		return 1;
1643	}
1644	/*
1645	 * Automatic sequencing; look for a candidate and
1646	 * if found join the network.
1647	 */
1648	/* NB: unlocked read should be ok */
1649	if (TAILQ_FIRST(&st->st_entry) == NULL) {
1650		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1651			"%s: no scan candidate\n", __func__);
1652		if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
1653			return 0;
1654notfound:
1655		/* NB: never auto-start a tdma network for slot !0 */
1656#ifdef IEEE80211_SUPPORT_TDMA
1657		if (vap->iv_des_nssid &&
1658		    ((vap->iv_caps & IEEE80211_C_TDMA) == 0 ||
1659		     ieee80211_tdma_getslot(vap) == 0)) {
1660#else
1661		if (vap->iv_des_nssid) {
1662#endif
1663			/*
1664			 * No existing adhoc network to join and we have
1665			 * an ssid; start one up.  If no channel was
1666			 * specified, try to select a channel.
1667			 */
1668			if (vap->iv_des_chan == IEEE80211_CHAN_ANYC ||
1669			    IEEE80211_IS_CHAN_RADAR(vap->iv_des_chan)) {
1670				chan = adhoc_pick_channel(ss, 0);
1671			} else
1672				chan = vap->iv_des_chan;
1673			if (chan != NULL) {
1674				/*
1675				 * Create a HT capable IBSS; the per-node
1676				 * probe request/response will result in
1677				 * "correct" rate control capabilities being
1678				 * negotiated.
1679				 */
1680				chan = ieee80211_ht_adjust_channel(ic,
1681				    chan, vap->iv_flags_ht);
1682				chan = ieee80211_vht_adjust_channel(ic,
1683				    chan, vap->iv_vht_flags);
1684				ieee80211_create_ibss(vap, chan);
1685				return 1;
1686			}
1687		}
1688		/*
1689		 * If nothing suitable was found decrement
1690		 * the failure counts so entries will be
1691		 * reconsidered the next time around.  We
1692		 * really want to do this only for sta's
1693		 * where we've previously had some success.
1694		 */
1695		sta_dec_fails(st);
1696		st->st_newscan = 1;
1697		return 0;			/* restart scan */
1698	}
1699	selbs = select_bss(ss, vap, IEEE80211_MSG_SCAN);
1700	if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
1701		return (selbs != NULL);
1702	if (selbs == NULL)
1703		goto notfound;
1704	chan = selbs->base.se_chan;
1705	if (selbs->se_flags & STA_DEMOTE11B)
1706		chan = demote11b(vap, chan);
1707	/*
1708	 * If HT is available, make it a possibility here.
1709	 * The intent is to enable HT20/HT40 when joining a non-HT
1710	 * IBSS node; we can then advertise HT IEs and speak HT
1711	 * to any subsequent nodes that support it.
1712	 */
1713	chan = ieee80211_ht_adjust_channel(ic,
1714	    chan, vap->iv_flags_ht);
1715	chan = ieee80211_vht_adjust_channel(ic,
1716	    chan, vap->iv_vht_flags);
1717	if (!ieee80211_sta_join(vap, chan, &selbs->base))
1718		goto notfound;
1719	return 1;				/* terminate scan */
1720}
1721
1722/*
1723 * Age entries in the scan cache.
1724 */
1725static void
1726adhoc_age(struct ieee80211_scan_state *ss)
1727{
1728	struct sta_table *st = ss->ss_priv;
1729	struct sta_entry *se, *next;
1730
1731	IEEE80211_SCAN_TABLE_LOCK(st);
1732	TAILQ_FOREACH_SAFE(se, &st->st_entry, se_list, next) {
1733		if (se->se_notseen > STA_PURGE_SCANS) {
1734			TAILQ_REMOVE(&st->st_entry, se, se_list);
1735			LIST_REMOVE(se, se_hash);
1736			ieee80211_ies_cleanup(&se->base.se_ies);
1737			IEEE80211_FREE(se, M_80211_SCAN);
1738		}
1739	}
1740	IEEE80211_SCAN_TABLE_UNLOCK(st);
1741}
1742
1743static const struct ieee80211_scanner adhoc_default = {
1744	.scan_name		= "default",
1745	.scan_attach		= sta_attach,
1746	.scan_detach		= sta_detach,
1747	.scan_start		= adhoc_start,
1748	.scan_restart		= sta_restart,
1749	.scan_cancel		= sta_cancel,
1750	.scan_end		= adhoc_pick_bss,
1751	.scan_flush		= sta_flush,
1752	.scan_pickchan		= adhoc_pick_channel,
1753	.scan_add		= sta_add,
1754	.scan_age		= adhoc_age,
1755	.scan_iterate		= sta_iterate,
1756	.scan_assoc_fail	= sta_assoc_fail,
1757	.scan_assoc_success	= sta_assoc_success,
1758};
1759IEEE80211_SCANNER_ALG(ibss, IEEE80211_M_IBSS, adhoc_default);
1760IEEE80211_SCANNER_ALG(ahdemo, IEEE80211_M_AHDEMO, adhoc_default);
1761
1762static int
1763ap_start(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
1764{
1765	struct sta_table *st = ss->ss_priv;
1766
1767	makescanlist(ss, vap, staScanTable);
1768
1769	if (ss->ss_mindwell == 0)
1770		ss->ss_mindwell = msecs_to_ticks(200);	/* 200ms */
1771	if (ss->ss_maxdwell == 0)
1772		ss->ss_maxdwell = msecs_to_ticks(200);	/* 200ms */
1773
1774	st->st_scangen++;
1775	st->st_newscan = 1;
1776
1777	return 0;
1778}
1779
1780/*
1781 * Cancel an ongoing scan.
1782 */
1783static int
1784ap_cancel(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
1785{
1786	return 0;
1787}
1788
1789/*
1790 * Pick a quiet channel to use for ap operation.
1791 */
1792static struct ieee80211_channel *
1793ap_pick_channel(struct ieee80211_scan_state *ss, int flags)
1794{
1795	struct sta_table *st = ss->ss_priv;
1796	struct ieee80211_channel *bestchan = NULL;
1797	int i;
1798
1799	/* XXX select channel more intelligently, e.g. channel spread, power */
1800	/* NB: use scan list order to preserve channel preference */
1801	for (i = 0; i < ss->ss_last; i++) {
1802		struct ieee80211_channel *chan = ss->ss_chans[i];
1803		/*
1804		 * If the channel is unoccupied the max rssi
1805		 * should be zero; just take it.  Otherwise
1806		 * track the channel with the lowest rssi and
1807		 * use that when all channels appear occupied.
1808		 */
1809		if (IEEE80211_IS_CHAN_RADAR(chan))
1810			continue;
1811		if (IEEE80211_IS_CHAN_NOHOSTAP(chan))
1812			continue;
1813		/* check channel attributes for band compatibility */
1814		if (flags != 0 && (chan->ic_flags & flags) != flags)
1815			continue;
1816		KASSERT(sizeof(chan->ic_ieee) == 1, ("ic_chan size"));
1817		/* XXX channel have interference */
1818		if (st->st_maxrssi[chan->ic_ieee] == 0) {
1819			/* XXX use other considerations */
1820			return chan;
1821		}
1822		if (bestchan == NULL ||
1823		    st->st_maxrssi[chan->ic_ieee] < st->st_maxrssi[bestchan->ic_ieee])
1824			bestchan = chan;
1825	}
1826	return bestchan;
1827}
1828
1829/*
1830 * Pick a quiet channel to use for ap operation.
1831 */
1832static int
1833ap_end(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
1834{
1835	struct ieee80211com *ic = vap->iv_ic;
1836	struct ieee80211_channel *bestchan, *chan;
1837
1838	KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP,
1839		("wrong opmode %u", vap->iv_opmode));
1840	bestchan = ap_pick_channel(ss, 0);
1841	if (bestchan == NULL) {
1842		/* no suitable channel, should not happen */
1843		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1844		    "%s: no suitable channel! (should not happen)\n", __func__);
1845		/* XXX print something? */
1846		return 0;			/* restart scan */
1847	}
1848	/*
1849	 * If this is a dynamic turbo channel, start with the unboosted one.
1850	 */
1851	if (IEEE80211_IS_CHAN_TURBO(bestchan)) {
1852		bestchan = ieee80211_find_channel(ic, bestchan->ic_freq,
1853			bestchan->ic_flags & ~IEEE80211_CHAN_TURBO);
1854		if (bestchan == NULL) {
1855			/* should never happen ?? */
1856			return 0;
1857		}
1858	}
1859	if (ss->ss_flags & (IEEE80211_SCAN_NOPICK | IEEE80211_SCAN_NOJOIN)) {
1860		/*
1861		 * Manual/background scan, don't select+join the
1862		 * bss, just return.  The scanning framework will
1863		 * handle notification that this has completed.
1864		 */
1865		ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
1866		return 1;
1867	}
1868	chan = ieee80211_ht_adjust_channel(ic, bestchan, vap->iv_flags_ht);
1869	chan = ieee80211_vht_adjust_channel(ic, chan, vap->iv_vht_flags);
1870	ieee80211_create_ibss(vap, chan);
1871
1872	return 1;
1873}
1874
1875static const struct ieee80211_scanner ap_default = {
1876	.scan_name		= "default",
1877	.scan_attach		= sta_attach,
1878	.scan_detach		= sta_detach,
1879	.scan_start		= ap_start,
1880	.scan_restart		= sta_restart,
1881	.scan_cancel		= ap_cancel,
1882	.scan_end		= ap_end,
1883	.scan_flush		= sta_flush,
1884	.scan_pickchan		= ap_pick_channel,
1885	.scan_add		= sta_add,
1886	.scan_age		= adhoc_age,
1887	.scan_iterate		= sta_iterate,
1888	.scan_assoc_success	= sta_assoc_success,
1889	.scan_assoc_fail	= sta_assoc_fail,
1890};
1891IEEE80211_SCANNER_ALG(ap, IEEE80211_M_HOSTAP, ap_default);
1892
1893#ifdef IEEE80211_SUPPORT_MESH
1894/*
1895 * Pick an mbss network to join or find a channel
1896 * to use to start an mbss network.
1897 */
1898static int
1899mesh_pick_bss(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
1900{
1901	struct sta_table *st = ss->ss_priv;
1902	struct ieee80211_mesh_state *ms = vap->iv_mesh;
1903	struct sta_entry *selbs;
1904	struct ieee80211_channel *chan;
1905
1906	KASSERT(vap->iv_opmode == IEEE80211_M_MBSS,
1907		("wrong opmode %u", vap->iv_opmode));
1908
1909	if (st->st_newscan) {
1910		sta_update_notseen(st);
1911		st->st_newscan = 0;
1912	}
1913	if (ss->ss_flags & IEEE80211_SCAN_NOPICK) {
1914		/*
1915		 * Manual/background scan, don't select+join the
1916		 * bss, just return.  The scanning framework will
1917		 * handle notification that this has completed.
1918		 */
1919		ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
1920		return 1;
1921	}
1922	/*
1923	 * Automatic sequencing; look for a candidate and
1924	 * if found join the network.
1925	 */
1926	/* NB: unlocked read should be ok */
1927	if (TAILQ_FIRST(&st->st_entry) == NULL) {
1928		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1929			"%s: no scan candidate\n", __func__);
1930		if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
1931			return 0;
1932notfound:
1933		if (ms->ms_idlen != 0) {
1934			/*
1935			 * No existing mbss network to join and we have
1936			 * a meshid; start one up.  If no channel was
1937			 * specified, try to select a channel.
1938			 */
1939			if (vap->iv_des_chan == IEEE80211_CHAN_ANYC ||
1940			    IEEE80211_IS_CHAN_RADAR(vap->iv_des_chan)) {
1941				struct ieee80211com *ic = vap->iv_ic;
1942
1943				/* XXX VHT */
1944				chan = adhoc_pick_channel(ss, 0);
1945				if (chan != NULL) {
1946					chan = ieee80211_ht_adjust_channel(ic,
1947					    chan, vap->iv_flags_ht);
1948					chan = ieee80211_vht_adjust_channel(ic,
1949					    chan, vap->iv_vht_flags);
1950					}
1951			} else
1952				chan = vap->iv_des_chan;
1953			if (chan != NULL) {
1954				ieee80211_create_ibss(vap, chan);
1955				return 1;
1956			}
1957		}
1958		/*
1959		 * If nothing suitable was found decrement
1960		 * the failure counts so entries will be
1961		 * reconsidered the next time around.  We
1962		 * really want to do this only for sta's
1963		 * where we've previously had some success.
1964		 */
1965		sta_dec_fails(st);
1966		st->st_newscan = 1;
1967		return 0;			/* restart scan */
1968	}
1969	selbs = select_bss(ss, vap, IEEE80211_MSG_SCAN);
1970	if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
1971		return (selbs != NULL);
1972	if (selbs == NULL)
1973		goto notfound;
1974	chan = selbs->base.se_chan;
1975	if (selbs->se_flags & STA_DEMOTE11B)
1976		chan = demote11b(vap, chan);
1977	if (!ieee80211_sta_join(vap, chan, &selbs->base))
1978		goto notfound;
1979	return 1;				/* terminate scan */
1980}
1981
1982static const struct ieee80211_scanner mesh_default = {
1983	.scan_name		= "default",
1984	.scan_attach		= sta_attach,
1985	.scan_detach		= sta_detach,
1986	.scan_start		= adhoc_start,
1987	.scan_restart		= sta_restart,
1988	.scan_cancel		= sta_cancel,
1989	.scan_end		= mesh_pick_bss,
1990	.scan_flush		= sta_flush,
1991	.scan_pickchan		= adhoc_pick_channel,
1992	.scan_add		= sta_add,
1993	.scan_age		= adhoc_age,
1994	.scan_iterate		= sta_iterate,
1995	.scan_assoc_fail	= sta_assoc_fail,
1996	.scan_assoc_success	= sta_assoc_success,
1997};
1998IEEE80211_SCANNER_ALG(mesh, IEEE80211_M_MBSS, mesh_default);
1999#endif /* IEEE80211_SUPPORT_MESH */
2000