First pass at converting the net80211 infrastrcture from FreeBSD.
[dragonfly.git] / sys / netproto / 802_11 / wlan / ieee80211_scan.c
1 /*-
2  * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  *
25  * $FreeBSD: head/sys/net80211/ieee80211_scan.c 195618 2009-07-11 15:02:45Z rpaulo $
26  * $DragonFly$
27  */
28
29 /*
30  * IEEE 802.11 scanning support.
31  */
32 #include "opt_wlan.h"
33
34 #include <sys/param.h>
35 #include <sys/systm.h> 
36 #include <sys/proc.h>
37 #include <sys/kernel.h>
38 #include <sys/condvar.h>
39  
40 #include <sys/socket.h>
41
42 #include <net/if.h>
43 #include <net/if_media.h>
44 #include <net/ethernet.h>
45 #include <net/route.h>
46
47 #include <netproto/802_11/ieee80211_var.h>
48
49 #include <net/bpf.h>
50
51 struct scan_state {
52         struct ieee80211_scan_state base;       /* public state */
53
54         u_int           ss_iflags;              /* flags used internally */
55 #define ISCAN_MINDWELL  0x0001          /* min dwell time reached */
56 #define ISCAN_DISCARD   0x0002          /* discard rx'd frames */
57 #define ISCAN_CANCEL    0x0004          /* cancel current scan */
58 #define ISCAN_ABORT     0x0008          /* end the scan immediately */
59         unsigned long   ss_chanmindwell;        /* min dwell on curchan */
60         unsigned long   ss_scanend;             /* time scan must stop */
61         u_int           ss_duration;            /* duration for next scan */
62         struct task     ss_scan_task;           /* scan execution */
63         struct cv       ss_scan_cv;             /* scan signal */
64         struct callout  ss_scan_timer;          /* scan timer */
65 };
66 #define SCAN_PRIVATE(ss)        ((struct scan_state *) ss)
67
68 /*
69  * Amount of time to go off-channel during a background
70  * scan.  This value should be large enough to catch most
71  * ap's but short enough that we can return on-channel
72  * before our listen interval expires.
73  *
74  * XXX tunable
75  * XXX check against configured listen interval
76  */
77 #define IEEE80211_SCAN_OFFCHANNEL       msecs_to_ticks(150)
78
79 /*
80  * Roaming-related defaults.  RSSI thresholds are as returned by the
81  * driver (.5dBm).  Transmit rate thresholds are IEEE rate codes (i.e
82  * .5M units) or MCS.
83  */
84 /* rssi thresholds */
85 #define ROAM_RSSI_11A_DEFAULT           14      /* 11a bss */
86 #define ROAM_RSSI_11B_DEFAULT           14      /* 11b bss */
87 #define ROAM_RSSI_11BONLY_DEFAULT       14      /* 11b-only bss */
88 /* transmit rate thresholds */
89 #define ROAM_RATE_11A_DEFAULT           2*12    /* 11a bss */
90 #define ROAM_RATE_11B_DEFAULT           2*5     /* 11b bss */
91 #define ROAM_RATE_11BONLY_DEFAULT       2*1     /* 11b-only bss */
92 #define ROAM_RATE_HALF_DEFAULT          2*6     /* half-width 11a/g bss */
93 #define ROAM_RATE_QUARTER_DEFAULT       2*3     /* quarter-width 11a/g bss */
94 #define ROAM_MCS_11N_DEFAULT            (1 | IEEE80211_RATE_MCS) /* 11n bss */
95
96 static  void scan_curchan(struct ieee80211_scan_state *, unsigned long);
97 static  void scan_mindwell(struct ieee80211_scan_state *);
98 static  void scan_signal(void *);
99 static  void scan_task(void *, int);
100
101 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
102
103 void
104 ieee80211_scan_attach(struct ieee80211com *ic)
105 {
106         struct scan_state *ss;
107
108         ss = (struct scan_state *) kmalloc(sizeof(struct scan_state),
109                 M_80211_SCAN, M_NOWAIT | M_ZERO);
110         if (ss == NULL) {
111                 ic->ic_scan = NULL;
112                 return;
113         }
114         callout_init_mtx(&ss->ss_scan_timer, IEEE80211_LOCK_OBJ(ic), 0);
115         cv_init(&ss->ss_scan_cv, "scan");
116         TASK_INIT(&ss->ss_scan_task, 0, scan_task, ss);
117         ic->ic_scan = &ss->base;
118         ss->base.ss_ic = ic;
119
120         ic->ic_scan_curchan = scan_curchan;
121         ic->ic_scan_mindwell = scan_mindwell;
122 }
123
124 void
125 ieee80211_scan_detach(struct ieee80211com *ic)
126 {
127         struct ieee80211_scan_state *ss = ic->ic_scan;
128
129         if (ss != NULL) {
130                 IEEE80211_LOCK(ic);
131                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
132                 scan_signal(ss);
133                 IEEE80211_UNLOCK(ic);
134                 ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
135                 callout_drain(&SCAN_PRIVATE(ss)->ss_scan_timer);
136                 KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0,
137                     ("scan still running"));
138                 if (ss->ss_ops != NULL) {
139                         ss->ss_ops->scan_detach(ss);
140                         ss->ss_ops = NULL;
141                 }
142                 ic->ic_scan = NULL;
143                 kfree(SCAN_PRIVATE(ss), M_80211_SCAN);
144         }
145 }
146
147 static const struct ieee80211_roamparam defroam[IEEE80211_MODE_MAX] = {
148         [IEEE80211_MODE_11A]    = { .rssi = ROAM_RSSI_11A_DEFAULT,
149                                     .rate = ROAM_RATE_11A_DEFAULT },
150         [IEEE80211_MODE_11G]    = { .rssi = ROAM_RSSI_11B_DEFAULT,
151                                     .rate = ROAM_RATE_11B_DEFAULT },
152         [IEEE80211_MODE_11B]    = { .rssi = ROAM_RSSI_11BONLY_DEFAULT,
153                                     .rate = ROAM_RATE_11BONLY_DEFAULT },
154         [IEEE80211_MODE_TURBO_A]= { .rssi = ROAM_RSSI_11A_DEFAULT,
155                                     .rate = ROAM_RATE_11A_DEFAULT },
156         [IEEE80211_MODE_TURBO_G]= { .rssi = ROAM_RSSI_11A_DEFAULT,
157                                     .rate = ROAM_RATE_11A_DEFAULT },
158         [IEEE80211_MODE_STURBO_A]={ .rssi = ROAM_RSSI_11A_DEFAULT,
159                                     .rate = ROAM_RATE_11A_DEFAULT },
160         [IEEE80211_MODE_HALF]   = { .rssi = ROAM_RSSI_11A_DEFAULT,
161                                     .rate = ROAM_RATE_HALF_DEFAULT },
162         [IEEE80211_MODE_QUARTER]= { .rssi = ROAM_RSSI_11A_DEFAULT,
163                                     .rate = ROAM_RATE_QUARTER_DEFAULT },
164         [IEEE80211_MODE_11NA]   = { .rssi = ROAM_RSSI_11A_DEFAULT,
165                                     .rate = ROAM_MCS_11N_DEFAULT },
166         [IEEE80211_MODE_11NG]   = { .rssi = ROAM_RSSI_11B_DEFAULT,
167                                     .rate = ROAM_MCS_11N_DEFAULT },
168 };
169
170 void
171 ieee80211_scan_vattach(struct ieee80211vap *vap)
172 {
173         vap->iv_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz;
174         vap->iv_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz;
175         vap->iv_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz;
176
177         vap->iv_roaming = IEEE80211_ROAMING_AUTO;
178         memcpy(vap->iv_roamparms, defroam, sizeof(defroam));
179 }
180
181 void
182 ieee80211_scan_vdetach(struct ieee80211vap *vap)
183 {
184         struct ieee80211com *ic = vap->iv_ic;
185         struct ieee80211_scan_state *ss;
186
187         IEEE80211_LOCK(ic);
188         ss = ic->ic_scan;
189         if (ss != NULL && ss->ss_vap == vap) {
190                 if (ic->ic_flags & IEEE80211_F_SCAN) {
191                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
192                         scan_signal(ss);
193                 }
194                 if (ss->ss_ops != NULL) {
195                         ss->ss_ops->scan_detach(ss);
196                         ss->ss_ops = NULL;
197                 }
198                 ss->ss_vap = NULL;
199         }
200         IEEE80211_UNLOCK(ic);
201 }
202
203 /*
204  * Simple-minded scanner module support.
205  */
206 static const char *scan_modnames[IEEE80211_OPMODE_MAX] = {
207         "wlan_scan_sta",        /* IEEE80211_M_IBSS */
208         "wlan_scan_sta",        /* IEEE80211_M_STA */
209         "wlan_scan_wds",        /* IEEE80211_M_WDS */
210         "wlan_scan_sta",        /* IEEE80211_M_AHDEMO */
211         "wlan_scan_ap",         /* IEEE80211_M_HOSTAP */
212         "wlan_scan_monitor",    /* IEEE80211_M_MONITOR */
213         "wlan_scan_sta",        /* IEEE80211_M_MBSS */
214 };
215 static const struct ieee80211_scanner *scanners[IEEE80211_OPMODE_MAX];
216
217 const struct ieee80211_scanner *
218 ieee80211_scanner_get(enum ieee80211_opmode mode)
219 {
220         if (mode >= IEEE80211_OPMODE_MAX)
221                 return NULL;
222         if (scanners[mode] == NULL)
223                 ieee80211_load_module(scan_modnames[mode]);
224         return scanners[mode];
225 }
226
227 void
228 ieee80211_scanner_register(enum ieee80211_opmode mode,
229         const struct ieee80211_scanner *scan)
230 {
231         if (mode >= IEEE80211_OPMODE_MAX)
232                 return;
233         scanners[mode] = scan;
234 }
235
236 void
237 ieee80211_scanner_unregister(enum ieee80211_opmode mode,
238         const struct ieee80211_scanner *scan)
239 {
240         if (mode >= IEEE80211_OPMODE_MAX)
241                 return;
242         if (scanners[mode] == scan)
243                 scanners[mode] = NULL;
244 }
245
246 void
247 ieee80211_scanner_unregister_all(const struct ieee80211_scanner *scan)
248 {
249         int m;
250
251         for (m = 0; m < IEEE80211_OPMODE_MAX; m++)
252                 if (scanners[m] == scan)
253                         scanners[m] = NULL;
254 }
255
256 /*
257  * Update common scanner state to reflect the current
258  * operating mode.  This is called when the state machine
259  * is transitioned to RUN state w/o scanning--e.g. when
260  * operating in monitor mode.  The purpose of this is to
261  * ensure later callbacks find ss_ops set to properly
262  * reflect current operating mode.
263  */
264 static void
265 scan_update_locked(struct ieee80211vap *vap,
266         const struct ieee80211_scanner *scan)
267 {
268         struct ieee80211com *ic = vap->iv_ic;
269         struct ieee80211_scan_state *ss = ic->ic_scan;
270
271         IEEE80211_LOCK_ASSERT(ic);
272
273 #ifdef IEEE80211_DEBUG
274         if (ss->ss_vap != vap || ss->ss_ops != scan) {
275                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
276                     "%s: current scanner is <%s:%s>, switch to <%s:%s>\n",
277                     __func__,
278                     ss->ss_vap != NULL ?
279                         ss->ss_vap->iv_ifp->if_xname : "none",
280                     ss->ss_vap != NULL ?
281                         ieee80211_opmode_name[ss->ss_vap->iv_opmode] : "none",
282                     vap->iv_ifp->if_xname,
283                     ieee80211_opmode_name[vap->iv_opmode]);
284         }
285 #endif
286         ss->ss_vap = vap;
287         if (ss->ss_ops != scan) {
288                 /*
289                  * Switch scanners; detach old, attach new.  Special
290                  * case where a single scan module implements multiple
291                  * policies by using different scan ops but a common
292                  * core.  We assume if the old and new attach methods
293                  * are identical then it's ok to just change ss_ops
294                  * and not flush the internal state of the module.
295                  */
296                 if (scan == NULL || ss->ss_ops == NULL ||
297                     ss->ss_ops->scan_attach != scan->scan_attach) {
298                         if (ss->ss_ops != NULL)
299                                 ss->ss_ops->scan_detach(ss);
300                         if (scan != NULL && !scan->scan_attach(ss)) {
301                                 /* XXX attach failure */
302                                 /* XXX stat+msg */
303                                 scan = NULL;
304                         }
305                 }
306                 ss->ss_ops = scan;
307         }
308 }
309
310 static char
311 channel_type(const struct ieee80211_channel *c)
312 {
313         if (IEEE80211_IS_CHAN_ST(c))
314                 return 'S';
315         if (IEEE80211_IS_CHAN_108A(c))
316                 return 'T';
317         if (IEEE80211_IS_CHAN_108G(c))
318                 return 'G';
319         if (IEEE80211_IS_CHAN_HT(c))
320                 return 'n';
321         if (IEEE80211_IS_CHAN_A(c))
322                 return 'a';
323         if (IEEE80211_IS_CHAN_ANYG(c))
324                 return 'g';
325         if (IEEE80211_IS_CHAN_B(c))
326                 return 'b';
327         return 'f';
328 }
329
330 void
331 ieee80211_scan_dump_channels(const struct ieee80211_scan_state *ss)
332 {
333         struct ieee80211com *ic = ss->ss_ic;
334         const char *sep;
335         int i;
336
337         sep = "";
338         for (i = ss->ss_next; i < ss->ss_last; i++) {
339                 const struct ieee80211_channel *c = ss->ss_chans[i];
340
341                 kprintf("%s%u%c", sep, ieee80211_chan2ieee(ic, c),
342                         channel_type(c));
343                 sep = ", ";
344         }
345 }
346
347 #ifdef IEEE80211_DEBUG
348 static void
349 scan_dump(struct ieee80211_scan_state *ss)
350 {
351         struct ieee80211vap *vap = ss->ss_vap;
352
353         if_printf(vap->iv_ifp, "scan set ");
354         ieee80211_scan_dump_channels(ss);
355         kprintf(" dwell min %lums max %lums\n",
356             ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(ss->ss_maxdwell));
357 }
358 #endif /* IEEE80211_DEBUG */
359
360 static void
361 copy_ssid(struct ieee80211vap *vap, struct ieee80211_scan_state *ss,
362         int nssid, const struct ieee80211_scan_ssid ssids[])
363 {
364         if (nssid > IEEE80211_SCAN_MAX_SSID) {
365                 /* XXX printf */
366                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
367                     "%s: too many ssid %d, ignoring all of them\n",
368                     __func__, nssid);
369                 return;
370         }
371         memcpy(ss->ss_ssid, ssids, nssid * sizeof(ssids[0]));
372         ss->ss_nssid = nssid;
373 }
374
375 /*
376  * Start a scan unless one is already going.
377  */
378 static int
379 start_scan_locked(const struct ieee80211_scanner *scan,
380         struct ieee80211vap *vap, int flags, u_int duration,
381         u_int mindwell, u_int maxdwell,
382         u_int nssid, const struct ieee80211_scan_ssid ssids[])
383 {
384         struct ieee80211com *ic = vap->iv_ic;
385         struct ieee80211_scan_state *ss = ic->ic_scan;
386
387         IEEE80211_LOCK_ASSERT(ic);
388
389         if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
390                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
391                     "%s: scan inhibited by pending channel change\n", __func__);
392         } else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
393                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
394                     "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
395                     , __func__
396                     , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
397                     , duration, mindwell, maxdwell
398                     , ieee80211_phymode_name[vap->iv_des_mode]
399                     , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
400                     , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
401                     , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
402                     , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
403                     , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
404                     , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
405                 );
406
407                 scan_update_locked(vap, scan);
408                 if (ss->ss_ops != NULL) {
409                         if ((flags & IEEE80211_SCAN_NOSSID) == 0)
410                                 copy_ssid(vap, ss, nssid, ssids);
411
412                         /* NB: top 4 bits for internal use */
413                         ss->ss_flags = flags & 0xfff;
414                         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
415                                 vap->iv_stats.is_scan_active++;
416                         else
417                                 vap->iv_stats.is_scan_passive++;
418                         if (flags & IEEE80211_SCAN_FLUSH)
419                                 ss->ss_ops->scan_flush(ss);
420
421                         /* NB: flush frames rx'd before 1st channel change */
422                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
423                         SCAN_PRIVATE(ss)->ss_duration = duration;
424                         ss->ss_next = 0;
425                         ss->ss_mindwell = mindwell;
426                         ss->ss_maxdwell = maxdwell;
427                         /* NB: scan_start must be before the scan runtask */
428                         ss->ss_ops->scan_start(ss, vap);
429 #ifdef IEEE80211_DEBUG
430                         if (ieee80211_msg_scan(vap))
431                                 scan_dump(ss);
432 #endif /* IEEE80211_DEBUG */
433                         ic->ic_flags |= IEEE80211_F_SCAN;
434                         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
435                 }
436         } else {
437                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
438                     "%s: %s scan already in progress\n", __func__,
439                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
440         }
441         return (ic->ic_flags & IEEE80211_F_SCAN);
442 }
443
444 /*
445  * Start a scan unless one is already going.
446  */
447 int
448 ieee80211_start_scan(struct ieee80211vap *vap, int flags,
449         u_int duration, u_int mindwell, u_int maxdwell,
450         u_int nssid, const struct ieee80211_scan_ssid ssids[])
451 {
452         struct ieee80211com *ic = vap->iv_ic;
453         const struct ieee80211_scanner *scan;
454         int result;
455
456         scan = ieee80211_scanner_get(vap->iv_opmode);
457         if (scan == NULL) {
458                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
459                     "%s: no scanner support for %s mode\n",
460                     __func__, ieee80211_opmode_name[vap->iv_opmode]);
461                 /* XXX stat */
462                 return 0;
463         }
464
465         IEEE80211_LOCK(ic);
466         result = start_scan_locked(scan, vap, flags, duration,
467             mindwell, maxdwell, nssid, ssids);
468         IEEE80211_UNLOCK(ic);
469
470         return result;
471 }
472
473 /*
474  * Check the scan cache for an ap/channel to use; if that
475  * fails then kick off a new scan.
476  */
477 int
478 ieee80211_check_scan(struct ieee80211vap *vap, int flags,
479         u_int duration, u_int mindwell, u_int maxdwell,
480         u_int nssid, const struct ieee80211_scan_ssid ssids[])
481 {
482         struct ieee80211com *ic = vap->iv_ic;
483         struct ieee80211_scan_state *ss = ic->ic_scan;
484         const struct ieee80211_scanner *scan;
485         int result;
486
487         scan = ieee80211_scanner_get(vap->iv_opmode);
488         if (scan == NULL) {
489                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
490                     "%s: no scanner support for %s mode\n",
491                     __func__, vap->iv_opmode);
492                 /* XXX stat */
493                 return 0;
494         }
495
496         /*
497          * Check if there's a list of scan candidates already.
498          * XXX want more than the ap we're currently associated with
499          */
500
501         IEEE80211_LOCK(ic);
502         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
503             "%s: %s scan, %s%s%s%s%s\n"
504             , __func__
505             , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
506             , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
507             , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
508             , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
509             , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
510             , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
511         );
512
513         if (ss->ss_ops != scan) {
514                 /* XXX re-use cache contents? e.g. adhoc<->sta */
515                 flags |= IEEE80211_SCAN_FLUSH;
516         }
517         scan_update_locked(vap, scan);
518         if (ss->ss_ops != NULL) {
519                 /* XXX verify ss_ops matches vap->iv_opmode */
520                 if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
521                         /*
522                          * Update the ssid list and mark flags so if
523                          * we call start_scan it doesn't duplicate work.
524                          */
525                         copy_ssid(vap, ss, nssid, ssids);
526                         flags |= IEEE80211_SCAN_NOSSID;
527                 }
528                 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
529                     (flags & IEEE80211_SCAN_FLUSH) == 0 &&
530                     time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
531                         /*
532                          * We're not currently scanning and the cache is
533                          * deemed hot enough to consult.  Lock out others
534                          * by marking IEEE80211_F_SCAN while we decide if
535                          * something is already in the scan cache we can
536                          * use.  Also discard any frames that might come
537                          * in while temporarily marked as scanning.
538                          */
539                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
540                         ic->ic_flags |= IEEE80211_F_SCAN;
541
542                         /* NB: need to use supplied flags in check */
543                         ss->ss_flags = flags & 0xff;
544                         result = ss->ss_ops->scan_end(ss, vap);
545
546                         ic->ic_flags &= ~IEEE80211_F_SCAN;
547                         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
548                         if (result) {
549                                 ieee80211_notify_scan_done(vap);
550                                 IEEE80211_UNLOCK(ic);
551                                 return 1;
552                         }
553                 }
554         }
555         result = start_scan_locked(scan, vap, flags, duration,
556             mindwell, maxdwell, nssid, ssids);
557         IEEE80211_UNLOCK(ic);
558
559         return result;
560 }
561
562 /*
563  * Check the scan cache for an ap/channel to use; if that fails
564  * then kick off a scan using the current settings.
565  */
566 int
567 ieee80211_check_scan_current(struct ieee80211vap *vap)
568 {
569         return ieee80211_check_scan(vap,
570             IEEE80211_SCAN_ACTIVE,
571             IEEE80211_SCAN_FOREVER, 0, 0,
572             vap->iv_des_nssid, vap->iv_des_ssid);
573 }
574
575 /*
576  * Restart a previous scan.  If the previous scan completed
577  * then we start again using the existing channel list.
578  */
579 int
580 ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
581 {
582         struct ieee80211com *ic = vap->iv_ic;
583         struct ieee80211_scan_state *ss = ic->ic_scan;
584         const struct ieee80211_scanner *scan;
585
586         scan = ieee80211_scanner_get(vap->iv_opmode);
587         if (scan == NULL) {
588                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
589                     "%s: no scanner support for %s mode\n",
590                     __func__, vap->iv_opmode);
591                 /* XXX stat */
592                 return 0;
593         }
594
595         IEEE80211_LOCK(ic);
596         if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
597                 u_int duration;
598                 /*
599                  * Go off-channel for a fixed interval that is large
600                  * enough to catch most ap's but short enough that
601                  * we can return on-channel before our listen interval
602                  * expires.
603                  */
604                 duration = IEEE80211_SCAN_OFFCHANNEL;
605
606                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
607                     "%s: %s scan, ticks %u duration %lu\n", __func__,
608                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
609                     ticks, duration);
610
611                 scan_update_locked(vap, scan);
612                 if (ss->ss_ops != NULL) {
613                         ss->ss_vap = vap;
614                         /*
615                          * A background scan does not select a new sta; it
616                          * just refreshes the scan cache.  Also, indicate
617                          * the scan logic should follow the beacon schedule:
618                          * we go off-channel and scan for a while, then
619                          * return to the bss channel to receive a beacon,
620                          * then go off-channel again.  All during this time
621                          * we notify the ap we're in power save mode.  When
622                          * the scan is complete we leave power save mode.
623                          * If any beacon indicates there are frames pending
624                          * for us then we drop out of power save mode
625                          * (and background scan) automatically by way of the
626                          * usual sta power save logic.
627                          */
628                         ss->ss_flags |= IEEE80211_SCAN_NOPICK
629                                      |  IEEE80211_SCAN_BGSCAN
630                                      |  flags
631                                      ;
632                         /* if previous scan completed, restart */
633                         if (ss->ss_next >= ss->ss_last) {
634                                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
635                                         vap->iv_stats.is_scan_active++;
636                                 else
637                                         vap->iv_stats.is_scan_passive++;
638                                 /*
639                                  * NB: beware of the scan cache being flushed;
640                                  *     if the channel list is empty use the
641                                  *     scan_start method to populate it.
642                                  */
643                                 ss->ss_next = 0;
644                                 if (ss->ss_last != 0)
645                                         ss->ss_ops->scan_restart(ss, vap);
646                                 else {
647                                         ss->ss_ops->scan_start(ss, vap);
648 #ifdef IEEE80211_DEBUG
649                                         if (ieee80211_msg_scan(vap))
650                                                 scan_dump(ss);
651 #endif /* IEEE80211_DEBUG */
652                                 }
653                         }
654                         /* NB: flush frames rx'd before 1st channel change */
655                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
656                         SCAN_PRIVATE(ss)->ss_duration = duration;
657                         ss->ss_maxdwell = duration;
658                         ic->ic_flags |= IEEE80211_F_SCAN;
659                         ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
660                         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
661                 } else {
662                         /* XXX msg+stat */
663                 }
664         } else {
665                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
666                     "%s: %s scan already in progress\n", __func__,
667                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
668         }
669         IEEE80211_UNLOCK(ic);
670
671         /* NB: racey, does it matter? */
672         return (ic->ic_flags & IEEE80211_F_SCAN);
673 }
674
675 /*
676  * Cancel any scan currently going on for the specified vap.
677  */
678 void
679 ieee80211_cancel_scan(struct ieee80211vap *vap)
680 {
681         struct ieee80211com *ic = vap->iv_ic;
682         struct ieee80211_scan_state *ss = ic->ic_scan;
683
684         IEEE80211_LOCK(ic);
685         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
686             ss->ss_vap == vap &&
687             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
688                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
689                     "%s: cancel %s scan\n", __func__,
690                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
691                         "active" : "passive");
692
693                 /* clear bg scan NOPICK and mark cancel request */
694                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
695                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
696                 /* wake up the scan task */
697                 scan_signal(ss);
698         }
699         IEEE80211_UNLOCK(ic);
700 }
701
702 /*
703  * Cancel any scan currently going on.
704  */
705 void
706 ieee80211_cancel_anyscan(struct ieee80211vap *vap)
707 {
708         struct ieee80211com *ic = vap->iv_ic;
709         struct ieee80211_scan_state *ss = ic->ic_scan;
710
711         IEEE80211_LOCK(ic);
712         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
713             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
714                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
715                     "%s: cancel %s scan\n", __func__,
716                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
717                         "active" : "passive");
718
719                 /* clear bg scan NOPICK and mark cancel request */
720                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
721                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
722                 /* wake up the scan task */
723                 scan_signal(ss);
724         }
725         IEEE80211_UNLOCK(ic);
726 }
727
728 /*
729  * Public access to scan_next for drivers that manage
730  * scanning themselves (e.g. for firmware-based devices).
731  */
732 void
733 ieee80211_scan_next(struct ieee80211vap *vap)
734 {
735         struct ieee80211com *ic = vap->iv_ic;
736         struct ieee80211_scan_state *ss = ic->ic_scan;
737
738         /* wake up the scan task */
739         IEEE80211_LOCK(ic);
740         scan_signal(ss);
741         IEEE80211_UNLOCK(ic);
742 }
743
744 /*
745  * Public access to scan_next for drivers that are not able to scan single
746  * channels (e.g. for firmware-based devices).
747  */
748 void
749 ieee80211_scan_done(struct ieee80211vap *vap)
750 {
751         struct ieee80211com *ic = vap->iv_ic;
752         struct ieee80211_scan_state *ss;
753
754         IEEE80211_LOCK(ic);
755         ss = ic->ic_scan;
756         ss->ss_next = ss->ss_last; /* all channels are complete */
757         scan_signal(ss);
758         IEEE80211_UNLOCK(ic);
759 }
760
761 /*
762  * Probe the curent channel, if allowed, while scanning.
763  * If the channel is not marked passive-only then send
764  * a probe request immediately.  Otherwise mark state and
765  * listen for beacons on the channel; if we receive something
766  * then we'll transmit a probe request.
767  */
768 void
769 ieee80211_probe_curchan(struct ieee80211vap *vap, int force)
770 {
771         struct ieee80211com *ic = vap->iv_ic;
772         struct ieee80211_scan_state *ss = ic->ic_scan;
773         struct ifnet *ifp = vap->iv_ifp;
774         int i;
775
776         if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
777                 ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
778                 return;
779         }
780         /*
781          * Send directed probe requests followed by any
782          * broadcast probe request.
783          * XXX remove dependence on ic/vap->iv_bss
784          */
785         for (i = 0; i < ss->ss_nssid; i++)
786                 ieee80211_send_probereq(vap->iv_bss,
787                         vap->iv_myaddr, ifp->if_broadcastaddr,
788                         ifp->if_broadcastaddr,
789                         ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
790         if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
791                 ieee80211_send_probereq(vap->iv_bss,
792                         vap->iv_myaddr, ifp->if_broadcastaddr,
793                         ifp->if_broadcastaddr,
794                         "", 0);
795 }
796
797 /*
798  * Scan curchan.  If this is an active scan and the channel
799  * is not marked passive then send probe request frame(s).
800  * Arrange for the channel change after maxdwell ticks.
801  */
802 static void
803 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
804 {
805         struct ieee80211vap *vap  = ss->ss_vap;
806
807         IEEE80211_LOCK(vap->iv_ic);
808         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
809                 ieee80211_probe_curchan(vap, 0);
810         callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
811             maxdwell, scan_signal, ss);
812         IEEE80211_UNLOCK(vap->iv_ic);
813 }
814
815 static void
816 scan_signal(void *arg)
817 {
818         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
819
820         IEEE80211_LOCK_ASSERT(ss->ss_ic);
821
822         cv_signal(&SCAN_PRIVATE(ss)->ss_scan_cv);
823 }
824
825 /*
826  * Handle mindwell requirements completed; initiate a channel
827  * change to the next channel asap.
828  */
829 static void
830 scan_mindwell(struct ieee80211_scan_state *ss)
831 {
832         struct ieee80211com *ic = ss->ss_ic;
833
834         IEEE80211_LOCK(ic);
835         scan_signal(ss);
836         IEEE80211_UNLOCK(ic);
837 }
838
839 static void
840 scan_task(void *arg, int pending)
841 {
842 #define ISCAN_REP       (ISCAN_MINDWELL | ISCAN_DISCARD)
843         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
844         struct ieee80211vap *vap = ss->ss_vap;
845         struct ieee80211com *ic = ss->ss_ic;
846         struct ieee80211_channel *chan;
847         unsigned long maxdwell, scanend;
848         int scandone = 0;
849
850         IEEE80211_LOCK(ic);
851         if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
852             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
853                 /* Cancelled before we started */
854                 goto done;
855         }
856
857         if (ss->ss_next == ss->ss_last) {
858                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
859                         "%s: no channels to scan\n", __func__);
860                 goto done;
861         }
862
863         if (vap->iv_opmode == IEEE80211_M_STA &&
864             vap->iv_state == IEEE80211_S_RUN) {
865                 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
866                         /* Enable station power save mode */
867                         ieee80211_sta_pwrsave(vap, 1);
868                         /*
869                          * Use an 1ms delay so the null data frame has a chance
870                          * to go out.
871                          * XXX Should use M_TXCB mechanism to eliminate this.
872                          */
873                         cv_timedwait(&SCAN_PRIVATE(ss)->ss_scan_cv,
874                             IEEE80211_LOCK_OBJ(ic), hz / 1000);
875                         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
876                                 goto done;
877                 }
878         }
879
880         scanend = ticks + SCAN_PRIVATE(ss)->ss_duration;
881         IEEE80211_UNLOCK(ic);
882         ic->ic_scan_start(ic);          /* notify driver */
883         IEEE80211_LOCK(ic);
884
885         for (;;) {
886                 scandone = (ss->ss_next >= ss->ss_last) ||
887                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0;
888                 if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
889                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT) ||
890                      time_after(ticks + ss->ss_mindwell, scanend))
891                         break;
892
893                 chan = ss->ss_chans[ss->ss_next++];
894
895                 /*
896                  * Watch for truncation due to the scan end time.
897                  */
898                 if (time_after(ticks + ss->ss_maxdwell, scanend))
899                         maxdwell = scanend - ticks;
900                 else
901                         maxdwell = ss->ss_maxdwell;
902
903                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
904                     "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
905                     __func__,
906                     ieee80211_chan2ieee(ic, ic->ic_curchan),
907                         channel_type(ic->ic_curchan),
908                     ieee80211_chan2ieee(ic, chan), channel_type(chan),
909                     (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
910                         (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
911                         "active" : "passive",
912                     ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
913
914                 /*
915                  * Potentially change channel and phy mode.
916                  */
917                 ic->ic_curchan = chan;
918                 ic->ic_rt = ieee80211_get_ratetable(chan);
919                 IEEE80211_UNLOCK(ic);
920                 /*
921                  * Perform the channel change and scan unlocked so the driver
922                  * may sleep. Once set_channel returns the hardware has
923                  * completed the channel change.
924                  */
925                 ic->ic_set_channel(ic);
926                 ieee80211_radiotap_chan_change(ic);
927
928                 /*
929                  * Scan curchan.  Drivers for "intelligent hardware"
930                  * override ic_scan_curchan to tell the device to do
931                  * the work.  Otherwise we manage the work outselves;
932                  * sending a probe request (as needed), and arming the
933                  * timeout to switch channels after maxdwell ticks.
934                  *
935                  * scan_curchan should only pause for the time required to
936                  * prepare/initiate the hardware for the scan (if at all), the
937                  * below condvar is used to sleep for the channels dwell time
938                  * and allows it to be signalled for abort.
939                  */
940                 ic->ic_scan_curchan(ss, maxdwell);
941                 IEEE80211_LOCK(ic);
942
943                 SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell;
944                 /* clear mindwell lock and initial channel change flush */
945                 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
946
947                 if ((SCAN_PRIVATE(ss)->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)))
948                         continue;
949
950                 /* Wait to be signalled to scan the next channel */
951                 cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv, IEEE80211_LOCK_OBJ(ic));
952         }
953         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
954                 goto done;
955
956         IEEE80211_UNLOCK(ic);
957         ic->ic_scan_end(ic);            /* notify driver */
958         IEEE80211_LOCK(ic);
959
960         /*
961          * Record scan complete time.  Note that we also do
962          * this when canceled so any background scan will
963          * not be restarted for a while.
964          */
965         if (scandone)
966                 ic->ic_lastscan = ticks;
967         /* return to the bss channel */
968         if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
969             ic->ic_curchan != ic->ic_bsschan) {
970                 ieee80211_setupcurchan(ic, ic->ic_bsschan);
971                 IEEE80211_UNLOCK(ic);
972                 ic->ic_set_channel(ic);
973                 ieee80211_radiotap_chan_change(ic);
974                 IEEE80211_LOCK(ic);
975         }
976         /* clear internal flags and any indication of a pick */
977         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
978         ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
979
980         /*
981          * If not canceled and scan completed, do post-processing.
982          * If the callback function returns 0, then it wants to
983          * continue/restart scanning.  Unfortunately we needed to
984          * notify the driver to end the scan above to avoid having
985          * rx frames alter the scan candidate list.
986          */
987         if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 &&
988             !ss->ss_ops->scan_end(ss, vap) &&
989             (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
990             time_before(ticks + ss->ss_mindwell, scanend)) {
991                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
992                     "%s: done, restart "
993                     "[ticks %u, dwell min %lu scanend %lu]\n",
994                     __func__,
995                     ticks, ss->ss_mindwell, scanend);
996                 ss->ss_next = 0;        /* reset to begining */
997                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
998                         vap->iv_stats.is_scan_active++;
999                 else
1000                         vap->iv_stats.is_scan_passive++;
1001
1002                 ss->ss_ops->scan_restart(ss, vap);      /* XXX? */
1003                 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
1004                 IEEE80211_UNLOCK(ic);
1005                 return;
1006         }
1007
1008         /* past here, scandone is ``true'' if not in bg mode */
1009         if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
1010                 scandone = 1;
1011
1012         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1013             "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
1014             __func__, scandone ? "done" : "stopped",
1015             ticks, ss->ss_mindwell, scanend);
1016
1017         /*
1018          * Clear the SCAN bit first in case frames are
1019          * pending on the station power save queue.  If
1020          * we defer this then the dispatch of the frames
1021          * may generate a request to cancel scanning.
1022          */
1023 done:
1024         ic->ic_flags &= ~IEEE80211_F_SCAN;
1025         /*
1026          * Drop out of power save mode when a scan has
1027          * completed.  If this scan was prematurely terminated
1028          * because it is a background scan then don't notify
1029          * the ap; we'll either return to scanning after we
1030          * receive the beacon frame or we'll drop out of power
1031          * save mode because the beacon indicates we have frames
1032          * waiting for us.
1033          */
1034         if (scandone) {
1035                 ieee80211_sta_pwrsave(vap, 0);
1036                 if (ss->ss_next >= ss->ss_last) {
1037                         ieee80211_notify_scan_done(vap);
1038                         ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
1039                 }
1040         }
1041         SCAN_PRIVATE(ss)->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
1042         ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
1043         IEEE80211_UNLOCK(ic);
1044 #undef ISCAN_REP
1045 }
1046
1047 #ifdef IEEE80211_DEBUG
1048 static void
1049 dump_country(const uint8_t *ie)
1050 {
1051         const struct ieee80211_country_ie *cie =
1052            (const struct ieee80211_country_ie *) ie;
1053         int i, nbands, schan, nchan;
1054
1055         if (cie->len < 3) {
1056                 kprintf(" <bogus country ie, len %d>", cie->len);
1057                 return;
1058         }
1059         kprintf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]);
1060         nbands = (cie->len - 3) / sizeof(cie->band[0]);
1061         for (i = 0; i < nbands; i++) {
1062                 schan = cie->band[i].schan;
1063                 nchan = cie->band[i].nchan;
1064                 if (nchan != 1)
1065                         kprintf(" %u-%u,%u", schan, schan + nchan-1,
1066                             cie->band[i].maxtxpwr);
1067                 else
1068                         kprintf(" %u,%u", schan, cie->band[i].maxtxpwr);
1069         }
1070         kprintf("]");
1071 }
1072
1073 static void
1074 dump_probe_beacon(uint8_t subtype, int isnew,
1075         const uint8_t mac[IEEE80211_ADDR_LEN],
1076         const struct ieee80211_scanparams *sp, int rssi)
1077 {
1078
1079         kprintf("[%s] %s%s on chan %u (bss chan %u) ",
1080             ether_sprintf(mac), isnew ? "new " : "",
1081             ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT],
1082             sp->chan, sp->bchan);
1083         ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
1084         kprintf(" rssi %d\n", rssi);
1085
1086         if (isnew) {
1087                 kprintf("[%s] caps 0x%x bintval %u erp 0x%x", 
1088                         ether_sprintf(mac), sp->capinfo, sp->bintval, sp->erp);
1089                 if (sp->country != NULL)
1090                         dump_country(sp->country);
1091                 kprintf("\n");
1092         }
1093 }
1094 #endif /* IEEE80211_DEBUG */
1095
1096 /*
1097  * Process a beacon or probe response frame.
1098  */
1099 void
1100 ieee80211_add_scan(struct ieee80211vap *vap,
1101         const struct ieee80211_scanparams *sp,
1102         const struct ieee80211_frame *wh,
1103         int subtype, int rssi, int noise)
1104 {
1105         struct ieee80211com *ic = vap->iv_ic;
1106         struct ieee80211_scan_state *ss = ic->ic_scan;
1107
1108         /* XXX locking */
1109         /*
1110          * Frames received during startup are discarded to avoid
1111          * using scan state setup on the initial entry to the timer
1112          * callback.  This can occur because the device may enable
1113          * rx prior to our doing the initial channel change in the
1114          * timer routine.
1115          */
1116         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
1117                 return;
1118 #ifdef IEEE80211_DEBUG
1119         if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
1120                 dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
1121 #endif
1122         if (ss->ss_ops != NULL &&
1123             ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise)) {
1124                 /*
1125                  * If we've reached the min dwell time terminate
1126                  * the timer so we'll switch to the next channel.
1127                  */
1128                 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
1129                     time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
1130                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1131                             "%s: chan %3d%c min dwell met (%u > %lu)\n",
1132                             __func__,
1133                             ieee80211_chan2ieee(ic, ic->ic_curchan),
1134                                 channel_type(ic->ic_curchan),
1135                             ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
1136                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
1137                         /*
1138                          * NB: trigger at next clock tick or wait for the
1139                          * hardware.
1140                          */
1141                         ic->ic_scan_mindwell(ss);
1142                 }
1143         }
1144 }
1145
1146 /*
1147  * Timeout/age scan cache entries; called from sta timeout
1148  * timer (XXX should be self-contained).
1149  */
1150 void
1151 ieee80211_scan_timeout(struct ieee80211com *ic)
1152 {
1153         struct ieee80211_scan_state *ss = ic->ic_scan;
1154
1155         if (ss->ss_ops != NULL)
1156                 ss->ss_ops->scan_age(ss);
1157 }
1158
1159 /*
1160  * Mark a scan cache entry after a successful associate.
1161  */
1162 void
1163 ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
1164 {
1165         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1166
1167         if (ss->ss_ops != NULL) {
1168                 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN,
1169                         mac, "%s",  __func__);
1170                 ss->ss_ops->scan_assoc_success(ss, mac);
1171         }
1172 }
1173
1174 /*
1175  * Demerit a scan cache entry after failing to associate.
1176  */
1177 void
1178 ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
1179         const uint8_t mac[], int reason)
1180 {
1181         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1182
1183         if (ss->ss_ops != NULL) {
1184                 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac,
1185                         "%s: reason %u", __func__, reason);
1186                 ss->ss_ops->scan_assoc_fail(ss, mac, reason);
1187         }
1188 }
1189
1190 /*
1191  * Iterate over the contents of the scan cache.
1192  */
1193 void
1194 ieee80211_scan_iterate(struct ieee80211vap *vap,
1195         ieee80211_scan_iter_func *f, void *arg)
1196 {
1197         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1198
1199         if (ss->ss_ops != NULL)
1200                 ss->ss_ops->scan_iterate(ss, f, arg);
1201 }
1202
1203 /*
1204  * Flush the contents of the scan cache.
1205  */
1206 void
1207 ieee80211_scan_flush(struct ieee80211vap *vap)
1208 {
1209         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1210
1211         if (ss->ss_ops != NULL && ss->ss_vap == vap) {
1212                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n",  __func__);
1213                 ss->ss_ops->scan_flush(ss);
1214         }
1215 }
1216
1217 /*
1218  * Check the scan cache for an ap/channel to use; if that
1219  * fails then kick off a new scan.
1220  */
1221 struct ieee80211_channel *
1222 ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
1223 {
1224         struct ieee80211_scan_state *ss = ic->ic_scan;
1225
1226         IEEE80211_LOCK_ASSERT(ic);
1227
1228         if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
1229                 /* XXX printf? */
1230                 return NULL;
1231         }
1232         if (ss->ss_ops->scan_pickchan == NULL) {
1233                 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
1234                     "%s: scan module does not support picking a channel, "
1235                     "opmode %s\n", __func__, ss->ss_vap->iv_opmode);
1236                 return NULL;
1237         }
1238         return ss->ss_ops->scan_pickchan(ss, flags);
1239 }