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
79 struct 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 # */
102 CTASSERT(MAX_IEEE_CHAN >= 256);
103
104 struct 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
116 static 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 */
142 static int match_bss(struct ieee80211vap *,
143 const struct ieee80211_scan_state *, struct sta_entry *, int);
144 static void adhoc_age(struct ieee80211_scan_state *);
145
146 static __inline int
isocmp(const uint8_t cc1[],const uint8_t cc2[])147 isocmp(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 */
153 static int nrefs = 0;
154 /*
155 * Module glue.
156 */
157 IEEE80211_SCANNER_MODULE(sta, 1);
158
159 /*
160 * Attach prior to any scanning work.
161 */
162 static int
sta_attach(struct ieee80211_scan_state * ss)163 sta_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 */
183 static int
sta_detach(struct ieee80211_scan_state * ss)184 sta_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 */
202 static int
sta_flush(struct ieee80211_scan_state * ss)203 sta_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 */
217 static void
sta_flush_table(struct sta_table * st)218 sta_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 */
235 static int
sta_add(struct ieee80211_scan_state * ss,struct ieee80211_channel * curchan,const struct ieee80211_scanparams * sp,const struct ieee80211_frame * wh,int subtype,int rssi,int noise)236 sta_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);
272 found:
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 */
426 static int
isexcluded(struct ieee80211vap * vap,const struct ieee80211_channel * c)427 isexcluded(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
434 static struct ieee80211_channel *
find11gchannel(struct ieee80211com * ic,int i,int freq)435 find11gchannel(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
458 static 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
477 static void
add_channels(struct ieee80211vap * vap,struct ieee80211_scan_state * ss,enum ieee80211_phymode mode,const uint16_t freq[],int nfreq)478 add_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
512 struct scanlist {
513 uint16_t mode;
514 uint16_t count;
515 const uint16_t *list;
516 };
517
518 static int
checktable(const struct scanlist * scan,const struct ieee80211_channel * c)519 checktable(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
531 static int
onscanlist(const struct ieee80211_scan_state * ss,const struct ieee80211_channel * c)532 onscanlist(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
543 static void
sweepchannels(struct ieee80211_scan_state * ss,struct ieee80211vap * vap,const struct scanlist table[])544 sweepchannels(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
609 static void
makescanlist(struct ieee80211_scan_state * ss,struct ieee80211vap * vap,const struct scanlist table[])610 makescanlist(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
688 static const uint16_t rcl1[] = /* 8 FCC channel: 52, 56, 60, 64, 36, 40, 44, 48 */
689 { 5260, 5280, 5300, 5320, 5180, 5200, 5220, 5240 };
690 static const uint16_t rcl2[] = /* 4 MKK channels: 34, 38, 42, 46 */
691 { 5170, 5190, 5210, 5230 };
692 static const uint16_t rcl3[] = /* 2.4Ghz ch: 1,6,11,7,13 */
693 { 2412, 2437, 2462, 2442, 2472 };
694 static const uint16_t rcl4[] = /* 5 FCC channel: 149, 153, 161, 165 */
695 { 5745, 5765, 5785, 5805, 5825 };
696 static 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 };
698 static const uint16_t rcl8[] = /* 2.4Ghz ch: 2,3,4,5,8,9,10,12 */
699 { 2417, 2422, 2427, 2432, 2447, 2452, 2457, 2467 };
700 static const uint16_t rcl9[] = /* 2.4Ghz ch: 14 */
701 { 2484 };
702 static const uint16_t rcl10[] = /* Added Korean channels 2312-2372 */
703 { 2312, 2317, 2322, 2327, 2332, 2337, 2342, 2347, 2352, 2357, 2362, 2367, 2372 };
704 static 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
707 static const uint16_t rcl5[] = /* 3 static turbo channels */
708 { 5210, 5250, 5290 };
709 static const uint16_t rcl6[] = /* 2 static turbo channels */
710 { 5760, 5800 };
711 static const uint16_t rcl6x[] = /* 4 FCC3 turbo channels */
712 { 5540, 5580, 5620, 5660 };
713 static const uint16_t rcl12[] = /* 2.4Ghz Turbo channel 6 */
714 { 2437 };
715 static 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
721 static 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 */
746 static int
sta_start(struct ieee80211_scan_state * ss,struct ieee80211vap * vap)747 sta_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 */
768 static int
sta_restart(struct ieee80211_scan_state * ss,struct ieee80211vap * vap)769 sta_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 */
780 static int
sta_cancel(struct ieee80211_scan_state * ss,struct ieee80211vap * vap)781 sta_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 */
790 static struct ieee80211_channel *
demote11b(struct ieee80211vap * vap,struct ieee80211_channel * chan)791 demote11b(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
806 static int
maxrate(const struct ieee80211_scan_entry * se)807 maxrate(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 */
868 static int
sta_compare(const struct sta_entry * a,const struct sta_entry * b)869 sta_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 */
918 static int
check_rate(struct ieee80211vap * vap,const struct ieee80211_channel * chan,const struct ieee80211_scan_entry * se)919 check_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;
934 again:
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
969 back:
970 if (okrate == 0 || ucastrate != fixedrate)
971 return badrate | IEEE80211_RATE_BASIC;
972 else
973 return IEEE80211_RV(okrate);
974 }
975
976 static __inline int
match_id(const uint8_t * ie,const uint8_t * val,int len)977 match_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
982 static int
match_ssid(const uint8_t * ie,int nssid,const struct ieee80211_scan_ssid ssids[])983 match_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
996 static int
tdma_isfull(const struct ieee80211_tdma_param * tdma)997 tdma_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 */
1012 static int
match_bss(struct ieee80211vap * vap,const struct ieee80211_scan_state * ss,struct sta_entry * se0,int debug)1013 match_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
1195 static void
sta_update_notseen(struct sta_table * st)1196 sta_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
1217 static void
sta_dec_fails(struct sta_table * st)1218 sta_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
1229 static struct sta_entry *
select_bss(struct ieee80211_scan_state * ss,struct ieee80211vap * vap,int debug)1230 select_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 */
1256 static int
sta_pick_bss(struct ieee80211_scan_state * ss,struct ieee80211vap * vap)1257 sta_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;
1293 notfound:
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 */
1326 static struct sta_entry *
sta_lookup(struct sta_table * st,const uint8_t macaddr[IEEE80211_ADDR_LEN])1327 sta_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
1341 static void
sta_roam_check(struct ieee80211_scan_state * ss,struct ieee80211vap * vap)1342 sta_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 */
1420 static void
sta_age(struct ieee80211_scan_state * ss)1421 sta_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 */
1448 static void
sta_iterate(struct ieee80211_scan_state * ss,ieee80211_scan_iter_func * f,void * arg)1449 sta_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++;
1458 restart:
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
1475 static void
sta_assoc_fail(struct ieee80211_scan_state * ss,const uint8_t macaddr[IEEE80211_ADDR_LEN],int reason)1476 sta_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
1492 static void
sta_assoc_success(struct ieee80211_scan_state * ss,const uint8_t macaddr[IEEE80211_ADDR_LEN])1493 sta_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
1511 static 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 };
1526 IEEE80211_SCANNER_ALG(sta, IEEE80211_M_STA, sta_default);
1527
1528 /*
1529 * Adhoc mode-specific support.
1530 */
1531
1532 static const uint16_t adhocWorld[] = /* 36, 40, 44, 48 */
1533 { 5180, 5200, 5220, 5240 };
1534 static 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 };
1536 static const uint16_t adhocMkk[] = /* 34, 38, 42, 46 */
1537 { 5170, 5190, 5210, 5230 };
1538 static const uint16_t adhoc11b[] = /* 10, 11 */
1539 { 2457, 2462 };
1540
1541 static 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 */
1553 static int
adhoc_start(struct ieee80211_scan_state * ss,struct ieee80211vap * vap)1554 adhoc_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 */
1576 static struct ieee80211_channel *
adhoc_pick_channel(struct ieee80211_scan_state * ss,int flags)1577 adhoc_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 */
1618 static int
adhoc_pick_bss(struct ieee80211_scan_state * ss,struct ieee80211vap * vap)1619 adhoc_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;
1654 notfound:
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 */
1725 static void
1726 adhoc_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
1743 static 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 };
1759 IEEE80211_SCANNER_ALG(ibss, IEEE80211_M_IBSS, adhoc_default);
1760 IEEE80211_SCANNER_ALG(ahdemo, IEEE80211_M_AHDEMO, adhoc_default);
1761
1762 static int
1763 ap_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 */
1783 static int
1784 ap_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 */
1792 static struct ieee80211_channel *
1793 ap_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 */
1832 static int
1833 ap_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
1875 static 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 };
1891 IEEE80211_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 */
1898 static int
1899 mesh_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;
1932 notfound:
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
1982 static 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 };
1998 IEEE80211_SCANNER_ALG(mesh, IEEE80211_M_MBSS, mesh_default);
1999 #endif /* IEEE80211_SUPPORT_MESH */
2000