2 * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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.
25 * $FreeBSD: head/sys/net80211/ieee80211_scan.c 195618 2009-07-11 15:02:45Z rpaulo $
30 * IEEE 802.11 scanning support.
34 #include <sys/param.h>
35 #include <sys/systm.h>
37 #include <sys/kernel.h>
39 #include <sys/condvar.h>
40 #include <sys/socket.h>
43 #include <net/if_media.h>
44 #include <net/ethernet.h>
45 #include <net/route.h>
47 #include <netproto/802_11/ieee80211_var.h>
52 struct ieee80211_scan_state base; /* public state */
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 */
66 #define SCAN_PRIVATE(ss) ((struct scan_state *) ss)
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.
75 * XXX check against configured listen interval
77 #define IEEE80211_SCAN_OFFCHANNEL msecs_to_ticks(150)
80 * Roaming-related defaults. RSSI thresholds are as returned by the
81 * driver (.5dBm). Transmit rate thresholds are IEEE rate codes (i.e
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 */
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);
101 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
104 ieee80211_scan_attach(struct ieee80211com *ic)
106 struct scan_state *ss;
108 ss = (struct scan_state *) kmalloc(sizeof(struct scan_state),
109 M_80211_SCAN, M_INTWAIT | M_ZERO);
114 cv_init(&ss->ss_scan_cv, "scan");
115 callout_init(&ss->ss_scan_timer);
116 TASK_INIT(&ss->ss_scan_task, 0, scan_task, ss);
117 ic->ic_scan = &ss->base;
120 ic->ic_scan_curchan = scan_curchan;
121 ic->ic_scan_mindwell = scan_mindwell;
125 ieee80211_scan_detach(struct ieee80211com *ic)
127 struct ieee80211_scan_state *ss = ic->ic_scan;
131 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
133 IEEE80211_UNLOCK(ic);
134 ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
135 callout_stop(&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);
143 kfree(SCAN_PRIVATE(ss), M_80211_SCAN);
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 },
171 ieee80211_scan_vattach(struct ieee80211vap *vap)
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;
177 vap->iv_roaming = IEEE80211_ROAMING_AUTO;
178 memcpy(vap->iv_roamparms, defroam, sizeof(defroam));
182 ieee80211_scan_vdetach(struct ieee80211vap *vap)
184 struct ieee80211com *ic = vap->iv_ic;
185 struct ieee80211_scan_state *ss;
189 if (ss != NULL && ss->ss_vap == vap) {
190 if (ic->ic_flags & IEEE80211_F_SCAN) {
191 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
194 if (ss->ss_ops != NULL) {
195 ss->ss_ops->scan_detach(ss);
200 IEEE80211_UNLOCK(ic);
204 * Simple-minded scanner module support.
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 */
215 static const struct ieee80211_scanner *scanners[IEEE80211_OPMODE_MAX];
217 const struct ieee80211_scanner *
218 ieee80211_scanner_get(enum ieee80211_opmode mode)
220 if (mode >= IEEE80211_OPMODE_MAX)
222 if (scanners[mode] == NULL)
223 ieee80211_load_module(scan_modnames[mode]);
224 return scanners[mode];
228 ieee80211_scanner_register(enum ieee80211_opmode mode,
229 const struct ieee80211_scanner *scan)
231 if (mode >= IEEE80211_OPMODE_MAX)
233 scanners[mode] = scan;
237 ieee80211_scanner_unregister(enum ieee80211_opmode mode,
238 const struct ieee80211_scanner *scan)
240 if (mode >= IEEE80211_OPMODE_MAX)
242 if (scanners[mode] == scan)
243 scanners[mode] = NULL;
247 ieee80211_scanner_unregister_all(const struct ieee80211_scanner *scan)
251 for (m = 0; m < IEEE80211_OPMODE_MAX; m++)
252 if (scanners[m] == scan)
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.
265 scan_update_locked(struct ieee80211vap *vap,
266 const struct ieee80211_scanner *scan)
268 struct ieee80211com *ic = vap->iv_ic;
269 struct ieee80211_scan_state *ss = ic->ic_scan;
271 IEEE80211_LOCK_ASSERT(ic);
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",
279 ss->ss_vap->iv_ifp->if_xname : "none",
281 ieee80211_opmode_name[ss->ss_vap->iv_opmode] : "none",
282 vap->iv_ifp->if_xname,
283 ieee80211_opmode_name[vap->iv_opmode]);
287 if (ss->ss_ops != scan) {
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.
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 */
311 channel_type(const struct ieee80211_channel *c)
313 if (IEEE80211_IS_CHAN_ST(c))
315 if (IEEE80211_IS_CHAN_108A(c))
317 if (IEEE80211_IS_CHAN_108G(c))
319 if (IEEE80211_IS_CHAN_HT(c))
321 if (IEEE80211_IS_CHAN_A(c))
323 if (IEEE80211_IS_CHAN_ANYG(c))
325 if (IEEE80211_IS_CHAN_B(c))
331 ieee80211_scan_dump_channels(const struct ieee80211_scan_state *ss)
333 struct ieee80211com *ic = ss->ss_ic;
338 for (i = ss->ss_next; i < ss->ss_last; i++) {
339 const struct ieee80211_channel *c = ss->ss_chans[i];
341 kprintf("%s%u%c", sep, ieee80211_chan2ieee(ic, c),
347 #ifdef IEEE80211_DEBUG
349 scan_dump(struct ieee80211_scan_state *ss)
351 struct ieee80211vap *vap = ss->ss_vap;
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));
358 #endif /* IEEE80211_DEBUG */
361 copy_ssid(struct ieee80211vap *vap, struct ieee80211_scan_state *ss,
362 int nssid, const struct ieee80211_scan_ssid ssids[])
364 if (nssid > IEEE80211_SCAN_MAX_SSID) {
366 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
367 "%s: too many ssid %d, ignoring all of them\n",
371 memcpy(ss->ss_ssid, ssids, nssid * sizeof(ssids[0]));
372 ss->ss_nssid = nssid;
376 * Start a scan unless one is already going.
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[])
384 struct ieee80211com *ic = vap->iv_ic;
385 struct ieee80211_scan_state *ss = ic->ic_scan;
387 IEEE80211_LOCK_ASSERT(ic);
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"
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" : ""
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);
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++;
417 vap->iv_stats.is_scan_passive++;
418 if (flags & IEEE80211_SCAN_FLUSH)
419 ss->ss_ops->scan_flush(ss);
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;
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))
432 #endif /* IEEE80211_DEBUG */
433 ic->ic_flags |= IEEE80211_F_SCAN;
434 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
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");
441 return (ic->ic_flags & IEEE80211_F_SCAN);
445 * Start a scan unless one is already going.
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[])
452 struct ieee80211com *ic = vap->iv_ic;
453 const struct ieee80211_scanner *scan;
456 scan = ieee80211_scanner_get(vap->iv_opmode);
458 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
459 "%s: no scanner support for %s mode\n",
460 __func__, ieee80211_opmode_name[vap->iv_opmode]);
466 result = start_scan_locked(scan, vap, flags, duration,
467 mindwell, maxdwell, nssid, ssids);
468 IEEE80211_UNLOCK(ic);
474 * Check the scan cache for an ap/channel to use; if that
475 * fails then kick off a new scan.
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[])
482 struct ieee80211com *ic = vap->iv_ic;
483 struct ieee80211_scan_state *ss = ic->ic_scan;
484 const struct ieee80211_scanner *scan;
487 scan = ieee80211_scanner_get(vap->iv_opmode);
489 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
490 "%s: no scanner support for %s mode\n",
491 __func__, vap->iv_opmode);
497 * Check if there's a list of scan candidates already.
498 * XXX want more than the ap we're currently associated with
502 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
503 "%s: %s scan, %s%s%s%s%s\n"
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" : ""
513 if (ss->ss_ops != scan) {
514 /* XXX re-use cache contents? e.g. adhoc<->sta */
515 flags |= IEEE80211_SCAN_FLUSH;
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) {
522 * Update the ssid list and mark flags so if
523 * we call start_scan it doesn't duplicate work.
525 copy_ssid(vap, ss, nssid, ssids);
526 flags |= IEEE80211_SCAN_NOSSID;
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)) {
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.
539 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
540 ic->ic_flags |= IEEE80211_F_SCAN;
542 /* NB: need to use supplied flags in check */
543 ss->ss_flags = flags & 0xff;
544 result = ss->ss_ops->scan_end(ss, vap);
546 ic->ic_flags &= ~IEEE80211_F_SCAN;
547 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
549 ieee80211_notify_scan_done(vap);
550 IEEE80211_UNLOCK(ic);
555 result = start_scan_locked(scan, vap, flags, duration,
556 mindwell, maxdwell, nssid, ssids);
557 IEEE80211_UNLOCK(ic);
563 * Check the scan cache for an ap/channel to use; if that fails
564 * then kick off a scan using the current settings.
567 ieee80211_check_scan_current(struct ieee80211vap *vap)
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);
576 * Restart a previous scan. If the previous scan completed
577 * then we start again using the existing channel list.
580 ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
582 struct ieee80211com *ic = vap->iv_ic;
583 struct ieee80211_scan_state *ss = ic->ic_scan;
584 const struct ieee80211_scanner *scan;
586 scan = ieee80211_scanner_get(vap->iv_opmode);
588 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
589 "%s: no scanner support for %s mode\n",
590 __func__, vap->iv_opmode);
596 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
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
604 duration = IEEE80211_SCAN_OFFCHANNEL;
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",
611 scan_update_locked(vap, scan);
612 if (ss->ss_ops != NULL) {
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.
628 ss->ss_flags |= IEEE80211_SCAN_NOPICK
629 | IEEE80211_SCAN_BGSCAN
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++;
637 vap->iv_stats.is_scan_passive++;
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.
644 if (ss->ss_last != 0)
645 ss->ss_ops->scan_restart(ss, vap);
647 ss->ss_ops->scan_start(ss, vap);
648 #ifdef IEEE80211_DEBUG
649 if (ieee80211_msg_scan(vap))
651 #endif /* IEEE80211_DEBUG */
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);
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");
669 IEEE80211_UNLOCK(ic);
671 /* NB: racey, does it matter? */
672 return (ic->ic_flags & IEEE80211_F_SCAN);
676 * Cancel any scan currently going on for the specified vap.
679 ieee80211_cancel_scan(struct ieee80211vap *vap)
681 struct ieee80211com *ic = vap->iv_ic;
682 struct ieee80211_scan_state *ss = ic->ic_scan;
685 if ((ic->ic_flags & IEEE80211_F_SCAN) &&
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");
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 */
699 IEEE80211_UNLOCK(ic);
703 * Cancel any scan currently going on.
706 ieee80211_cancel_anyscan(struct ieee80211vap *vap)
708 struct ieee80211com *ic = vap->iv_ic;
709 struct ieee80211_scan_state *ss = ic->ic_scan;
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");
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 */
725 IEEE80211_UNLOCK(ic);
729 * Public access to scan_next for drivers that manage
730 * scanning themselves (e.g. for firmware-based devices).
733 ieee80211_scan_next(struct ieee80211vap *vap)
735 struct ieee80211com *ic = vap->iv_ic;
736 struct ieee80211_scan_state *ss = ic->ic_scan;
738 /* wake up the scan task */
741 IEEE80211_UNLOCK(ic);
745 * Public access to scan_next for drivers that are not able to scan single
746 * channels (e.g. for firmware-based devices).
749 ieee80211_scan_done(struct ieee80211vap *vap)
751 struct ieee80211com *ic = vap->iv_ic;
752 struct ieee80211_scan_state *ss;
756 ss->ss_next = ss->ss_last; /* all channels are complete */
758 IEEE80211_UNLOCK(ic);
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.
769 ieee80211_probe_curchan(struct ieee80211vap *vap, int force)
771 struct ieee80211com *ic = vap->iv_ic;
772 struct ieee80211_scan_state *ss = ic->ic_scan;
773 struct ifnet *ifp = vap->iv_ifp;
776 if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
777 ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
781 * Send directed probe requests followed by any
782 * broadcast probe request.
783 * XXX remove dependence on ic/vap->iv_bss
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,
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.
803 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
805 struct ieee80211vap *vap = ss->ss_vap;
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);
816 scan_signal(void *arg)
818 struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
820 IEEE80211_LOCK(ss->ss_ic);
821 cv_signal(&SCAN_PRIVATE(ss)->ss_scan_cv);
822 IEEE80211_UNLOCK(ss->ss_ic);
826 * Handle mindwell requirements completed; initiate a channel
827 * change to the next channel asap.
830 scan_mindwell(struct ieee80211_scan_state *ss)
832 struct ieee80211com *ic = ss->ss_ic;
836 IEEE80211_UNLOCK(ic);
840 scan_task(void *arg, int pending)
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;
851 if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
852 (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
853 /* Cancelled before we started */
857 if (ss->ss_next == ss->ss_last) {
858 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
859 "%s: no channels to scan\n", __func__);
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);
869 * Use an 1ms delay so the null data frame has a chance
871 * XXX Should use M_TXCB mechanism to eliminate this.
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)
880 scanend = ticks + SCAN_PRIVATE(ss)->ss_duration;
881 IEEE80211_UNLOCK(ic);
882 ic->ic_scan_start(ic); /* notify driver */
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))
893 chan = ss->ss_chans[ss->ss_next++];
896 * Watch for truncation due to the scan end time.
898 if (time_after(ticks + ss->ss_maxdwell, scanend))
899 maxdwell = scanend - ticks;
901 maxdwell = ss->ss_maxdwell;
903 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
904 "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
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));
915 * Potentially change channel and phy mode.
917 ic->ic_curchan = chan;
918 ic->ic_rt = ieee80211_get_ratetable(chan);
919 IEEE80211_UNLOCK(ic);
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.
925 ic->ic_set_channel(ic);
926 ieee80211_radiotap_chan_change(ic);
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.
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.
940 ic->ic_scan_curchan(ss, maxdwell);
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;
947 if ((SCAN_PRIVATE(ss)->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)))
950 /* Wait to be signalled to scan the next channel */
951 cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv, IEEE80211_LOCK_OBJ(ic));
953 if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
956 IEEE80211_UNLOCK(ic);
957 ic->ic_scan_end(ic); /* notify driver */
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.
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);
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;
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.
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,
993 "[ticks %u, dwell min %lu scanend %lu]\n",
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++;
1000 vap->iv_stats.is_scan_passive++;
1002 ss->ss_ops->scan_restart(ss, vap); /* XXX? */
1003 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
1004 IEEE80211_UNLOCK(ic);
1008 /* past here, scandone is ``true'' if not in bg mode */
1009 if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
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);
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.
1024 ic->ic_flags &= ~IEEE80211_F_SCAN;
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
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;
1041 SCAN_PRIVATE(ss)->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
1042 ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
1043 IEEE80211_UNLOCK(ic);
1047 #ifdef IEEE80211_DEBUG
1049 dump_country(const uint8_t *ie)
1051 const struct ieee80211_country_ie *cie =
1052 (const struct ieee80211_country_ie *) ie;
1053 int i, nbands, schan, nchan;
1056 kprintf(" <bogus country ie, len %d>", cie->len);
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;
1065 kprintf(" %u-%u,%u", schan, schan + nchan-1,
1066 cie->band[i].maxtxpwr);
1068 kprintf(" %u,%u", schan, cie->band[i].maxtxpwr);
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)
1079 kprintf("[%6D] %s%s on chan %u (bss chan %u) ",
1080 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);
1087 kprintf("[%6D] caps 0x%x bintval %u erp 0x%x",
1088 mac, ":", sp->capinfo, sp->bintval, sp->erp);
1089 if (sp->country != NULL)
1090 dump_country(sp->country);
1094 #endif /* IEEE80211_DEBUG */
1097 * Process a beacon or probe response frame.
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)
1105 struct ieee80211com *ic = vap->iv_ic;
1106 struct ieee80211_scan_state *ss = ic->ic_scan;
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
1116 if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
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);
1122 if (ss->ss_ops != NULL &&
1123 ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise)) {
1125 * If we've reached the min dwell time terminate
1126 * the timer so we'll switch to the next channel.
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",
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;
1138 * NB: trigger at next clock tick or wait for the
1141 ic->ic_scan_mindwell(ss);
1147 * Timeout/age scan cache entries; called from sta timeout
1148 * timer (XXX should be self-contained).
1151 ieee80211_scan_timeout(struct ieee80211com *ic)
1153 struct ieee80211_scan_state *ss = ic->ic_scan;
1155 if (ss->ss_ops != NULL)
1156 ss->ss_ops->scan_age(ss);
1160 * Mark a scan cache entry after a successful associate.
1163 ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
1165 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
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);
1175 * Demerit a scan cache entry after failing to associate.
1178 ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
1179 const uint8_t mac[], int reason)
1181 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
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);
1191 * Iterate over the contents of the scan cache.
1194 ieee80211_scan_iterate(struct ieee80211vap *vap,
1195 ieee80211_scan_iter_func *f, void *arg)
1197 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1199 if (ss->ss_ops != NULL)
1200 ss->ss_ops->scan_iterate(ss, f, arg);
1204 * Flush the contents of the scan cache.
1207 ieee80211_scan_flush(struct ieee80211vap *vap)
1209 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
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);
1218 * Check the scan cache for an ap/channel to use; if that
1219 * fails then kick off a new scan.
1221 struct ieee80211_channel *
1222 ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
1224 struct ieee80211_scan_state *ss = ic->ic_scan;
1226 IEEE80211_LOCK_ASSERT(ic);
1228 if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
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);
1238 return ss->ss_ops->scan_pickchan(ss, flags);