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.
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
30 * IEEE 802.11 scanning support.
34 #include <sys/param.h>
35 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/condvar.h>
40 #include <sys/socket.h>
43 #include <net/if_var.h>
44 #include <net/if_media.h>
45 #include <net/ethernet.h>
47 #include <net80211/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 *) malloc(sizeof(struct scan_state),
109 M_80211_SCAN, M_NOWAIT | M_ZERO);
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;
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_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);
143 free(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 printf("%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 printf(" 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);
420 if (flags & IEEE80211_SCAN_BGSCAN)
421 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
423 /* NB: flush frames rx'd before 1st channel change */
424 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
425 SCAN_PRIVATE(ss)->ss_duration = duration;
427 ss->ss_mindwell = mindwell;
428 ss->ss_maxdwell = maxdwell;
429 /* NB: scan_start must be before the scan runtask */
430 ss->ss_ops->scan_start(ss, vap);
431 #ifdef IEEE80211_DEBUG
432 if (ieee80211_msg_scan(vap))
434 #endif /* IEEE80211_DEBUG */
435 ic->ic_flags |= IEEE80211_F_SCAN;
436 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
440 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
441 "%s: %s scan already in progress\n", __func__,
442 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
448 * Start a scan unless one is already going.
451 ieee80211_start_scan(struct ieee80211vap *vap, int flags,
452 u_int duration, u_int mindwell, u_int maxdwell,
453 u_int nssid, const struct ieee80211_scan_ssid ssids[])
455 struct ieee80211com *ic = vap->iv_ic;
456 const struct ieee80211_scanner *scan;
459 scan = ieee80211_scanner_get(vap->iv_opmode);
461 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
462 "%s: no scanner support for %s mode\n",
463 __func__, ieee80211_opmode_name[vap->iv_opmode]);
469 result = start_scan_locked(scan, vap, flags, duration,
470 mindwell, maxdwell, nssid, ssids);
471 IEEE80211_UNLOCK(ic);
477 * Check the scan cache for an ap/channel to use; if that
478 * fails then kick off a new scan.
481 ieee80211_check_scan(struct ieee80211vap *vap, int flags,
482 u_int duration, u_int mindwell, u_int maxdwell,
483 u_int nssid, const struct ieee80211_scan_ssid ssids[])
485 struct ieee80211com *ic = vap->iv_ic;
486 struct ieee80211_scan_state *ss = ic->ic_scan;
487 const struct ieee80211_scanner *scan;
490 scan = ieee80211_scanner_get(vap->iv_opmode);
492 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
493 "%s: no scanner support for %s mode\n",
494 __func__, vap->iv_opmode);
500 * Check if there's a list of scan candidates already.
501 * XXX want more than the ap we're currently associated with
505 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
506 "%s: %s scan, %s%s%s%s%s\n"
508 , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
509 , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
510 , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
511 , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
512 , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
513 , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
516 if (ss->ss_ops != scan) {
517 /* XXX re-use cache contents? e.g. adhoc<->sta */
518 flags |= IEEE80211_SCAN_FLUSH;
520 scan_update_locked(vap, scan);
521 if (ss->ss_ops != NULL) {
522 /* XXX verify ss_ops matches vap->iv_opmode */
523 if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
525 * Update the ssid list and mark flags so if
526 * we call start_scan it doesn't duplicate work.
528 copy_ssid(vap, ss, nssid, ssids);
529 flags |= IEEE80211_SCAN_NOSSID;
531 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
532 (flags & IEEE80211_SCAN_FLUSH) == 0 &&
533 time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
535 * We're not currently scanning and the cache is
536 * deemed hot enough to consult. Lock out others
537 * by marking IEEE80211_F_SCAN while we decide if
538 * something is already in the scan cache we can
539 * use. Also discard any frames that might come
540 * in while temporarily marked as scanning.
542 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
543 ic->ic_flags |= IEEE80211_F_SCAN;
545 /* NB: need to use supplied flags in check */
546 ss->ss_flags = flags & 0xff;
547 result = ss->ss_ops->scan_end(ss, vap);
549 ic->ic_flags &= ~IEEE80211_F_SCAN;
550 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
552 ieee80211_notify_scan_done(vap);
553 IEEE80211_UNLOCK(ic);
558 result = start_scan_locked(scan, vap, flags, duration,
559 mindwell, maxdwell, nssid, ssids);
560 IEEE80211_UNLOCK(ic);
566 * Check the scan cache for an ap/channel to use; if that fails
567 * then kick off a scan using the current settings.
570 ieee80211_check_scan_current(struct ieee80211vap *vap)
572 return ieee80211_check_scan(vap,
573 IEEE80211_SCAN_ACTIVE,
574 IEEE80211_SCAN_FOREVER, 0, 0,
575 vap->iv_des_nssid, vap->iv_des_ssid);
579 * Restart a previous scan. If the previous scan completed
580 * then we start again using the existing channel list.
583 ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
585 struct ieee80211com *ic = vap->iv_ic;
586 struct ieee80211_scan_state *ss = ic->ic_scan;
587 const struct ieee80211_scanner *scan;
589 scan = ieee80211_scanner_get(vap->iv_opmode);
591 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
592 "%s: no scanner support for %s mode\n",
593 __func__, vap->iv_opmode);
599 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
602 * Go off-channel for a fixed interval that is large
603 * enough to catch most ap's but short enough that
604 * we can return on-channel before our listen interval
607 duration = IEEE80211_SCAN_OFFCHANNEL;
609 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
610 "%s: %s scan, ticks %u duration %lu\n", __func__,
611 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
614 scan_update_locked(vap, scan);
615 if (ss->ss_ops != NULL) {
618 * A background scan does not select a new sta; it
619 * just refreshes the scan cache. Also, indicate
620 * the scan logic should follow the beacon schedule:
621 * we go off-channel and scan for a while, then
622 * return to the bss channel to receive a beacon,
623 * then go off-channel again. All during this time
624 * we notify the ap we're in power save mode. When
625 * the scan is complete we leave power save mode.
626 * If any beacon indicates there are frames pending
627 * for us then we drop out of power save mode
628 * (and background scan) automatically by way of the
629 * usual sta power save logic.
631 ss->ss_flags |= IEEE80211_SCAN_NOPICK
632 | IEEE80211_SCAN_BGSCAN
635 /* if previous scan completed, restart */
636 if (ss->ss_next >= ss->ss_last) {
637 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
638 vap->iv_stats.is_scan_active++;
640 vap->iv_stats.is_scan_passive++;
642 * NB: beware of the scan cache being flushed;
643 * if the channel list is empty use the
644 * scan_start method to populate it.
647 if (ss->ss_last != 0)
648 ss->ss_ops->scan_restart(ss, vap);
650 ss->ss_ops->scan_start(ss, vap);
651 #ifdef IEEE80211_DEBUG
652 if (ieee80211_msg_scan(vap))
654 #endif /* IEEE80211_DEBUG */
657 /* NB: flush frames rx'd before 1st channel change */
658 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
659 SCAN_PRIVATE(ss)->ss_duration = duration;
660 ss->ss_maxdwell = duration;
661 ic->ic_flags |= IEEE80211_F_SCAN;
662 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
663 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
668 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
669 "%s: %s scan already in progress\n", __func__,
670 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
672 IEEE80211_UNLOCK(ic);
674 /* NB: racey, does it matter? */
675 return (ic->ic_flags & IEEE80211_F_SCAN);
679 * Cancel any scan currently going on for the specified vap.
682 ieee80211_cancel_scan(struct ieee80211vap *vap)
684 struct ieee80211com *ic = vap->iv_ic;
685 struct ieee80211_scan_state *ss = ic->ic_scan;
688 if ((ic->ic_flags & IEEE80211_F_SCAN) &&
690 (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
691 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
692 "%s: cancel %s scan\n", __func__,
693 ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
694 "active" : "passive");
696 /* clear bg scan NOPICK and mark cancel request */
697 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
698 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
699 /* wake up the scan task */
702 IEEE80211_UNLOCK(ic);
706 * Cancel any scan currently going on.
709 ieee80211_cancel_anyscan(struct ieee80211vap *vap)
711 struct ieee80211com *ic = vap->iv_ic;
712 struct ieee80211_scan_state *ss = ic->ic_scan;
715 if ((ic->ic_flags & IEEE80211_F_SCAN) &&
716 (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
717 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
718 "%s: cancel %s scan\n", __func__,
719 ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
720 "active" : "passive");
722 /* clear bg scan NOPICK and mark cancel request */
723 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
724 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
725 /* wake up the scan task */
728 IEEE80211_UNLOCK(ic);
732 * Public access to scan_next for drivers that manage
733 * scanning themselves (e.g. for firmware-based devices).
736 ieee80211_scan_next(struct ieee80211vap *vap)
738 struct ieee80211com *ic = vap->iv_ic;
739 struct ieee80211_scan_state *ss = ic->ic_scan;
741 /* wake up the scan task */
744 IEEE80211_UNLOCK(ic);
748 * Public access to scan_next for drivers that are not able to scan single
749 * channels (e.g. for firmware-based devices).
752 ieee80211_scan_done(struct ieee80211vap *vap)
754 struct ieee80211com *ic = vap->iv_ic;
755 struct ieee80211_scan_state *ss;
759 ss->ss_next = ss->ss_last; /* all channels are complete */
761 IEEE80211_UNLOCK(ic);
765 * Probe the curent channel, if allowed, while scanning.
766 * If the channel is not marked passive-only then send
767 * a probe request immediately. Otherwise mark state and
768 * listen for beacons on the channel; if we receive something
769 * then we'll transmit a probe request.
772 ieee80211_probe_curchan(struct ieee80211vap *vap, int force)
774 struct ieee80211com *ic = vap->iv_ic;
775 struct ieee80211_scan_state *ss = ic->ic_scan;
776 struct ifnet *ifp = vap->iv_ifp;
779 if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
780 ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
784 * Send directed probe requests followed by any
785 * broadcast probe request.
786 * XXX remove dependence on ic/vap->iv_bss
788 for (i = 0; i < ss->ss_nssid; i++)
789 ieee80211_send_probereq(vap->iv_bss,
790 vap->iv_myaddr, ifp->if_broadcastaddr,
791 ifp->if_broadcastaddr,
792 ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
793 if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
794 ieee80211_send_probereq(vap->iv_bss,
795 vap->iv_myaddr, ifp->if_broadcastaddr,
796 ifp->if_broadcastaddr,
801 * Scan curchan. If this is an active scan and the channel
802 * is not marked passive then send probe request frame(s).
803 * Arrange for the channel change after maxdwell ticks.
806 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
808 struct ieee80211vap *vap = ss->ss_vap;
810 IEEE80211_LOCK(vap->iv_ic);
811 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
812 ieee80211_probe_curchan(vap, 0);
813 callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
814 maxdwell, scan_signal, ss);
815 IEEE80211_UNLOCK(vap->iv_ic);
819 scan_signal(void *arg)
821 struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
823 IEEE80211_LOCK_ASSERT(ss->ss_ic);
825 cv_signal(&SCAN_PRIVATE(ss)->ss_scan_cv);
829 * Handle mindwell requirements completed; initiate a channel
830 * change to the next channel asap.
833 scan_mindwell(struct ieee80211_scan_state *ss)
835 struct ieee80211com *ic = ss->ss_ic;
839 IEEE80211_UNLOCK(ic);
843 scan_task(void *arg, int pending)
845 #define ISCAN_REP (ISCAN_MINDWELL | ISCAN_DISCARD)
846 struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
847 struct ieee80211vap *vap = ss->ss_vap;
848 struct ieee80211com *ic = ss->ss_ic;
849 struct ieee80211_channel *chan;
850 unsigned long maxdwell, scanend;
854 if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
855 (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
856 /* Cancelled before we started */
860 if (ss->ss_next == ss->ss_last) {
861 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
862 "%s: no channels to scan\n", __func__);
867 if (vap->iv_opmode == IEEE80211_M_STA &&
868 vap->iv_state == IEEE80211_S_RUN) {
869 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
870 /* Enable station power save mode */
871 vap->iv_sta_ps(vap, 1);
873 * Use an 1ms delay so the null data frame has a chance
875 * XXX Should use M_TXCB mechanism to eliminate this.
877 cv_timedwait(&SCAN_PRIVATE(ss)->ss_scan_cv,
878 IEEE80211_LOCK_OBJ(ic), hz / 1000);
879 if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
884 scanend = ticks + SCAN_PRIVATE(ss)->ss_duration;
885 IEEE80211_UNLOCK(ic);
886 ic->ic_scan_start(ic); /* notify driver */
890 scandone = (ss->ss_next >= ss->ss_last) ||
891 (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0;
892 if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
893 (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT) ||
894 time_after(ticks + ss->ss_mindwell, scanend))
897 chan = ss->ss_chans[ss->ss_next++];
900 * Watch for truncation due to the scan end time.
902 if (time_after(ticks + ss->ss_maxdwell, scanend))
903 maxdwell = scanend - ticks;
905 maxdwell = ss->ss_maxdwell;
907 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
908 "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
910 ieee80211_chan2ieee(ic, ic->ic_curchan),
911 channel_type(ic->ic_curchan),
912 ieee80211_chan2ieee(ic, chan), channel_type(chan),
913 (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
914 (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
915 "active" : "passive",
916 ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
919 * Potentially change channel and phy mode.
921 ic->ic_curchan = chan;
922 ic->ic_rt = ieee80211_get_ratetable(chan);
923 IEEE80211_UNLOCK(ic);
925 * Perform the channel change and scan unlocked so the driver
926 * may sleep. Once set_channel returns the hardware has
927 * completed the channel change.
929 ic->ic_set_channel(ic);
930 ieee80211_radiotap_chan_change(ic);
933 * Scan curchan. Drivers for "intelligent hardware"
934 * override ic_scan_curchan to tell the device to do
935 * the work. Otherwise we manage the work outselves;
936 * sending a probe request (as needed), and arming the
937 * timeout to switch channels after maxdwell ticks.
939 * scan_curchan should only pause for the time required to
940 * prepare/initiate the hardware for the scan (if at all), the
941 * below condvar is used to sleep for the channels dwell time
942 * and allows it to be signalled for abort.
944 ic->ic_scan_curchan(ss, maxdwell);
947 SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell;
948 /* clear mindwell lock and initial channel change flush */
949 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
951 if ((SCAN_PRIVATE(ss)->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)))
954 /* Wait to be signalled to scan the next channel */
955 cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv, IEEE80211_LOCK_OBJ(ic));
957 if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
960 IEEE80211_UNLOCK(ic);
961 ic->ic_scan_end(ic); /* notify driver */
965 * Since a cancellation may have occured during one of the
966 * driver calls (whilst unlocked), update scandone.
969 ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0)) {
971 if_printf(vap->iv_ifp,
972 "%s: OOPS! scan cancelled during driver call!\n",
975 scandone |= ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0);
978 * Record scan complete time. Note that we also do
979 * this when canceled so any background scan will
980 * not be restarted for a while.
983 ic->ic_lastscan = ticks;
984 /* return to the bss channel */
985 if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
986 ic->ic_curchan != ic->ic_bsschan) {
987 ieee80211_setupcurchan(ic, ic->ic_bsschan);
988 IEEE80211_UNLOCK(ic);
989 ic->ic_set_channel(ic);
990 ieee80211_radiotap_chan_change(ic);
993 /* clear internal flags and any indication of a pick */
994 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
995 ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
998 * If not canceled and scan completed, do post-processing.
999 * If the callback function returns 0, then it wants to
1000 * continue/restart scanning. Unfortunately we needed to
1001 * notify the driver to end the scan above to avoid having
1002 * rx frames alter the scan candidate list.
1004 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 &&
1005 !ss->ss_ops->scan_end(ss, vap) &&
1006 (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
1007 time_before(ticks + ss->ss_mindwell, scanend)) {
1008 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1009 "%s: done, restart "
1010 "[ticks %u, dwell min %lu scanend %lu]\n",
1012 ticks, ss->ss_mindwell, scanend);
1013 ss->ss_next = 0; /* reset to begining */
1014 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
1015 vap->iv_stats.is_scan_active++;
1017 vap->iv_stats.is_scan_passive++;
1019 ss->ss_ops->scan_restart(ss, vap); /* XXX? */
1020 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
1021 IEEE80211_UNLOCK(ic);
1025 /* past here, scandone is ``true'' if not in bg mode */
1026 if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
1029 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1030 "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
1031 __func__, scandone ? "done" : "stopped",
1032 ticks, ss->ss_mindwell, scanend);
1035 * Clear the SCAN bit first in case frames are
1036 * pending on the station power save queue. If
1037 * we defer this then the dispatch of the frames
1038 * may generate a request to cancel scanning.
1041 ic->ic_flags &= ~IEEE80211_F_SCAN;
1043 * Drop out of power save mode when a scan has
1044 * completed. If this scan was prematurely terminated
1045 * because it is a background scan then don't notify
1046 * the ap; we'll either return to scanning after we
1047 * receive the beacon frame or we'll drop out of power
1048 * save mode because the beacon indicates we have frames
1052 vap->iv_sta_ps(vap, 0);
1053 if (ss->ss_next >= ss->ss_last) {
1054 ieee80211_notify_scan_done(vap);
1055 ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
1058 SCAN_PRIVATE(ss)->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
1059 ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
1060 IEEE80211_UNLOCK(ic);
1064 #ifdef IEEE80211_DEBUG
1066 dump_country(const uint8_t *ie)
1068 const struct ieee80211_country_ie *cie =
1069 (const struct ieee80211_country_ie *) ie;
1070 int i, nbands, schan, nchan;
1073 printf(" <bogus country ie, len %d>", cie->len);
1076 printf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]);
1077 nbands = (cie->len - 3) / sizeof(cie->band[0]);
1078 for (i = 0; i < nbands; i++) {
1079 schan = cie->band[i].schan;
1080 nchan = cie->band[i].nchan;
1082 printf(" %u-%u,%u", schan, schan + nchan-1,
1083 cie->band[i].maxtxpwr);
1085 printf(" %u,%u", schan, cie->band[i].maxtxpwr);
1091 dump_probe_beacon(uint8_t subtype, int isnew,
1092 const uint8_t mac[IEEE80211_ADDR_LEN],
1093 const struct ieee80211_scanparams *sp, int rssi)
1096 printf("[%s] %s%s on chan %u (bss chan %u) ",
1097 ether_sprintf(mac), isnew ? "new " : "",
1098 ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT],
1099 sp->chan, sp->bchan);
1100 ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
1101 printf(" rssi %d\n", rssi);
1104 printf("[%s] caps 0x%x bintval %u erp 0x%x",
1105 ether_sprintf(mac), sp->capinfo, sp->bintval, sp->erp);
1106 if (sp->country != NULL)
1107 dump_country(sp->country);
1111 #endif /* IEEE80211_DEBUG */
1114 * Process a beacon or probe response frame.
1117 ieee80211_add_scan(struct ieee80211vap *vap,
1118 const struct ieee80211_scanparams *sp,
1119 const struct ieee80211_frame *wh,
1120 int subtype, int rssi, int noise)
1122 struct ieee80211com *ic = vap->iv_ic;
1123 struct ieee80211_scan_state *ss = ic->ic_scan;
1127 * Frames received during startup are discarded to avoid
1128 * using scan state setup on the initial entry to the timer
1129 * callback. This can occur because the device may enable
1130 * rx prior to our doing the initial channel change in the
1133 if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
1135 #ifdef IEEE80211_DEBUG
1136 if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
1137 dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
1139 if (ss->ss_ops != NULL &&
1140 ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise)) {
1142 * If we've reached the min dwell time terminate
1143 * the timer so we'll switch to the next channel.
1145 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
1146 time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
1147 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1148 "%s: chan %3d%c min dwell met (%u > %lu)\n",
1150 ieee80211_chan2ieee(ic, ic->ic_curchan),
1151 channel_type(ic->ic_curchan),
1152 ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
1153 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
1155 * NB: trigger at next clock tick or wait for the
1158 ic->ic_scan_mindwell(ss);
1164 * Timeout/age scan cache entries; called from sta timeout
1165 * timer (XXX should be self-contained).
1168 ieee80211_scan_timeout(struct ieee80211com *ic)
1170 struct ieee80211_scan_state *ss = ic->ic_scan;
1172 if (ss->ss_ops != NULL)
1173 ss->ss_ops->scan_age(ss);
1177 * Mark a scan cache entry after a successful associate.
1180 ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
1182 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1184 if (ss->ss_ops != NULL) {
1185 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN,
1186 mac, "%s", __func__);
1187 ss->ss_ops->scan_assoc_success(ss, mac);
1192 * Demerit a scan cache entry after failing to associate.
1195 ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
1196 const uint8_t mac[], int reason)
1198 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1200 if (ss->ss_ops != NULL) {
1201 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac,
1202 "%s: reason %u", __func__, reason);
1203 ss->ss_ops->scan_assoc_fail(ss, mac, reason);
1208 * Iterate over the contents of the scan cache.
1211 ieee80211_scan_iterate(struct ieee80211vap *vap,
1212 ieee80211_scan_iter_func *f, void *arg)
1214 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1216 if (ss->ss_ops != NULL)
1217 ss->ss_ops->scan_iterate(ss, f, arg);
1221 * Flush the contents of the scan cache.
1224 ieee80211_scan_flush(struct ieee80211vap *vap)
1226 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1228 if (ss->ss_ops != NULL && ss->ss_vap == vap) {
1229 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n", __func__);
1230 ss->ss_ops->scan_flush(ss);
1235 * Check the scan cache for an ap/channel to use; if that
1236 * fails then kick off a new scan.
1238 struct ieee80211_channel *
1239 ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
1241 struct ieee80211_scan_state *ss = ic->ic_scan;
1243 IEEE80211_LOCK_ASSERT(ic);
1245 if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
1249 if (ss->ss_ops->scan_pickchan == NULL) {
1250 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
1251 "%s: scan module does not support picking a channel, "
1252 "opmode %s\n", __func__, ss->ss_vap->iv_opmode);
1255 return ss->ss_ops->scan_pickchan(ss, flags);