2 * Scanning implementation
4 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
5 * Copyright 2004, Instant802 Networks, Inc.
6 * Copyright 2005, Devicescape Software, Inc.
7 * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
8 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
15 /* TODO: figure out how to avoid that the "current BSS" expires */
17 #include <linux/wireless.h>
18 #include <linux/if_arp.h>
19 #include <linux/rtnetlink.h>
20 #include <net/mac80211.h>
21 #include <net/iw_handler.h>
23 #include "ieee80211_i.h"
26 #define IEEE80211_PROBE_DELAY (HZ / 33)
27 #define IEEE80211_CHANNEL_TIME (HZ / 33)
28 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)
30 struct ieee80211_bss
*
31 ieee80211_rx_bss_get(struct ieee80211_local
*local
, u8
*bssid
, int freq
,
32 u8
*ssid
, u8 ssid_len
)
34 return (void *)cfg80211_get_bss(local
->hw
.wiphy
,
35 ieee80211_get_channel(local
->hw
.wiphy
,
37 bssid
, ssid
, ssid_len
,
41 static void ieee80211_rx_bss_free(struct cfg80211_bss
*cbss
)
43 struct ieee80211_bss
*bss
= (void *)cbss
;
45 kfree(bss_mesh_id(bss
));
46 kfree(bss_mesh_cfg(bss
));
49 void ieee80211_rx_bss_put(struct ieee80211_local
*local
,
50 struct ieee80211_bss
*bss
)
52 cfg80211_put_bss((struct cfg80211_bss
*)bss
);
55 struct ieee80211_bss
*
56 ieee80211_bss_info_update(struct ieee80211_local
*local
,
57 struct ieee80211_rx_status
*rx_status
,
58 struct ieee80211_mgmt
*mgmt
,
60 struct ieee802_11_elems
*elems
,
61 struct ieee80211_channel
*channel
,
64 struct ieee80211_bss
*bss
;
68 if (local
->hw
.flags
& IEEE80211_HW_SIGNAL_DBM
)
69 signal
= rx_status
->signal
* 100;
70 else if (local
->hw
.flags
& IEEE80211_HW_SIGNAL_UNSPEC
)
71 signal
= (rx_status
->signal
* 100) / local
->hw
.max_signal
;
73 bss
= (void *)cfg80211_inform_bss_frame(local
->hw
.wiphy
, channel
,
74 mgmt
, len
, signal
, GFP_ATOMIC
);
79 bss
->cbss
.free_priv
= ieee80211_rx_bss_free
;
81 /* save the ERP value so that it is available at association time */
82 if (elems
->erp_info
&& elems
->erp_info_len
>= 1) {
83 bss
->erp_value
= elems
->erp_info
[0];
84 bss
->has_erp_value
= 1;
88 struct ieee80211_tim_ie
*tim_ie
=
89 (struct ieee80211_tim_ie
*)elems
->tim
;
90 bss
->dtim_period
= tim_ie
->dtim_period
;
93 /* set default value for buggy APs */
94 if (!elems
->tim
|| bss
->dtim_period
== 0)
97 bss
->supp_rates_len
= 0;
98 if (elems
->supp_rates
) {
99 clen
= IEEE80211_MAX_SUPP_RATES
- bss
->supp_rates_len
;
100 if (clen
> elems
->supp_rates_len
)
101 clen
= elems
->supp_rates_len
;
102 memcpy(&bss
->supp_rates
[bss
->supp_rates_len
], elems
->supp_rates
,
104 bss
->supp_rates_len
+= clen
;
106 if (elems
->ext_supp_rates
) {
107 clen
= IEEE80211_MAX_SUPP_RATES
- bss
->supp_rates_len
;
108 if (clen
> elems
->ext_supp_rates_len
)
109 clen
= elems
->ext_supp_rates_len
;
110 memcpy(&bss
->supp_rates
[bss
->supp_rates_len
],
111 elems
->ext_supp_rates
, clen
);
112 bss
->supp_rates_len
+= clen
;
115 bss
->wmm_used
= elems
->wmm_param
|| elems
->wmm_info
;
118 bss
->last_probe_resp
= jiffies
;
123 void ieee80211_rx_bss_remove(struct ieee80211_sub_if_data
*sdata
, u8
*bssid
,
124 int freq
, u8
*ssid
, u8 ssid_len
)
126 struct ieee80211_bss
*bss
;
127 struct ieee80211_local
*local
= sdata
->local
;
129 bss
= ieee80211_rx_bss_get(local
, bssid
, freq
, ssid
, ssid_len
);
131 cfg80211_unlink_bss(local
->hw
.wiphy
, (void *)bss
);
132 ieee80211_rx_bss_put(local
, bss
);
137 ieee80211_scan_rx(struct ieee80211_sub_if_data
*sdata
, struct sk_buff
*skb
,
138 struct ieee80211_rx_status
*rx_status
)
140 struct ieee80211_mgmt
*mgmt
;
141 struct ieee80211_bss
*bss
;
143 struct ieee80211_channel
*channel
;
147 bool presp
, beacon
= false;
148 struct ieee802_11_elems elems
;
151 return RX_DROP_UNUSABLE
;
153 mgmt
= (struct ieee80211_mgmt
*) skb
->data
;
154 fc
= mgmt
->frame_control
;
156 if (ieee80211_is_ctl(fc
))
160 return RX_DROP_MONITOR
;
162 presp
= ieee80211_is_probe_resp(fc
);
164 /* ignore ProbeResp to foreign address */
165 if (memcmp(mgmt
->da
, sdata
->dev
->dev_addr
, ETH_ALEN
))
166 return RX_DROP_MONITOR
;
169 elements
= mgmt
->u
.probe_resp
.variable
;
170 baselen
= offsetof(struct ieee80211_mgmt
, u
.probe_resp
.variable
);
172 beacon
= ieee80211_is_beacon(fc
);
173 baselen
= offsetof(struct ieee80211_mgmt
, u
.beacon
.variable
);
174 elements
= mgmt
->u
.beacon
.variable
;
177 if (!presp
&& !beacon
)
180 if (baselen
> skb
->len
)
181 return RX_DROP_MONITOR
;
183 ieee802_11_parse_elems(elements
, skb
->len
- baselen
, &elems
);
185 if (elems
.ds_params
&& elems
.ds_params_len
== 1)
186 freq
= ieee80211_channel_to_frequency(elems
.ds_params
[0]);
188 freq
= rx_status
->freq
;
190 channel
= ieee80211_get_channel(sdata
->local
->hw
.wiphy
, freq
);
192 if (!channel
|| channel
->flags
& IEEE80211_CHAN_DISABLED
)
193 return RX_DROP_MONITOR
;
195 bss
= ieee80211_bss_info_update(sdata
->local
, rx_status
,
196 mgmt
, skb
->len
, &elems
,
199 ieee80211_rx_bss_put(sdata
->local
, bss
);
206 * inform AP that we will go to sleep so that it will buffer the frames
209 static void ieee80211_scan_ps_enable(struct ieee80211_sub_if_data
*sdata
)
211 struct ieee80211_local
*local
= sdata
->local
;
214 /* FIXME: what to do when local->pspolling is true? */
216 del_timer_sync(&local
->dynamic_ps_timer
);
217 cancel_work_sync(&local
->dynamic_ps_enable_work
);
219 if (local
->hw
.conf
.flags
& IEEE80211_CONF_PS
) {
221 local
->hw
.conf
.flags
&= ~IEEE80211_CONF_PS
;
222 ieee80211_hw_config(local
, IEEE80211_CONF_CHANGE_PS
);
225 if (!ps
|| !(local
->hw
.flags
& IEEE80211_HW_PS_NULLFUNC_STACK
))
227 * If power save was enabled, no need to send a nullfunc
228 * frame because AP knows that we are sleeping. But if the
229 * hardware is creating the nullfunc frame for power save
230 * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
231 * enabled) and power save was enabled, the firmware just
232 * sent a null frame with power save disabled. So we need
233 * to send a new nullfunc frame to inform the AP that we
234 * are again sleeping.
236 ieee80211_send_nullfunc(local
, sdata
, 1);
239 /* inform AP that we are awake again, unless power save is enabled */
240 static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data
*sdata
)
242 struct ieee80211_local
*local
= sdata
->local
;
244 if (!local
->ps_sdata
)
245 ieee80211_send_nullfunc(local
, sdata
, 0);
248 * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
249 * will send a nullfunc frame with the powersave bit set
250 * even though the AP already knows that we are sleeping.
251 * This could be avoided by sending a null frame with power
252 * save bit disabled before enabling the power save, but
253 * this doesn't gain anything.
255 * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
256 * to send a nullfunc frame because AP already knows that
257 * we are sleeping, let's just enable power save mode in
260 local
->hw
.conf
.flags
|= IEEE80211_CONF_PS
;
261 ieee80211_hw_config(local
, IEEE80211_CONF_CHANGE_PS
);
265 static void ieee80211_restore_scan_ies(struct ieee80211_local
*local
)
267 kfree(local
->scan_req
->ie
);
268 local
->scan_req
->ie
= local
->orig_ies
;
269 local
->scan_req
->ie_len
= local
->orig_ies_len
;
272 void ieee80211_scan_completed(struct ieee80211_hw
*hw
, bool aborted
)
274 struct ieee80211_local
*local
= hw_to_local(hw
);
275 struct ieee80211_sub_if_data
*sdata
;
278 mutex_lock(&local
->scan_mtx
);
280 if (WARN_ON(!local
->hw_scanning
&& !local
->sw_scanning
)) {
281 mutex_unlock(&local
->scan_mtx
);
285 if (WARN_ON(!local
->scan_req
)) {
286 mutex_unlock(&local
->scan_mtx
);
290 if (local
->hw_scanning
)
291 ieee80211_restore_scan_ies(local
);
293 if (local
->scan_req
!= &local
->int_scan_req
)
294 cfg80211_scan_done(local
->scan_req
, aborted
);
295 local
->scan_req
= NULL
;
297 was_hw_scan
= local
->hw_scanning
;
298 local
->hw_scanning
= false;
299 local
->sw_scanning
= false;
301 /* we only have to protect scan_req and hw/sw scan */
302 mutex_unlock(&local
->scan_mtx
);
306 * Somebody might have requested channel change during scan
307 * that we won't have acted upon, try now. ieee80211_hw_config
308 * will set the flag based on actual changes.
310 ieee80211_hw_config(local
, 0);
314 ieee80211_hw_config(local
, IEEE80211_CONF_CHANGE_CHANNEL
);
316 netif_tx_lock_bh(local
->mdev
);
317 netif_addr_lock(local
->mdev
);
318 local
->filter_flags
&= ~FIF_BCN_PRBRESP_PROMISC
;
319 local
->ops
->configure_filter(local_to_hw(local
),
320 FIF_BCN_PRBRESP_PROMISC
,
321 &local
->filter_flags
,
322 local
->mdev
->mc_count
,
323 local
->mdev
->mc_list
);
325 netif_addr_unlock(local
->mdev
);
326 netif_tx_unlock_bh(local
->mdev
);
328 if (local
->ops
->sw_scan_complete
)
329 local
->ops
->sw_scan_complete(local_to_hw(local
));
331 mutex_lock(&local
->iflist_mtx
);
332 list_for_each_entry(sdata
, &local
->interfaces
, list
) {
333 if (!netif_running(sdata
->dev
))
336 /* Tell AP we're back */
337 if (sdata
->vif
.type
== NL80211_IFTYPE_STATION
) {
338 if (sdata
->u
.mgd
.flags
& IEEE80211_STA_ASSOCIATED
) {
339 ieee80211_scan_ps_disable(sdata
);
340 netif_tx_wake_all_queues(sdata
->dev
);
343 netif_tx_wake_all_queues(sdata
->dev
);
345 /* re-enable beaconing */
346 if (sdata
->vif
.type
== NL80211_IFTYPE_AP
||
347 sdata
->vif
.type
== NL80211_IFTYPE_ADHOC
||
348 sdata
->vif
.type
== NL80211_IFTYPE_MESH_POINT
)
349 ieee80211_bss_info_change_notify(
350 sdata
, BSS_CHANGED_BEACON_ENABLED
);
352 mutex_unlock(&local
->iflist_mtx
);
355 ieee80211_mlme_notify_scan_completed(local
);
356 ieee80211_ibss_notify_scan_completed(local
);
357 ieee80211_mesh_notify_scan_completed(local
);
359 EXPORT_SYMBOL(ieee80211_scan_completed
);
361 static int ieee80211_start_sw_scan(struct ieee80211_local
*local
)
363 struct ieee80211_sub_if_data
*sdata
;
366 * Hardware/driver doesn't support hw_scan, so use software
367 * scanning instead. First send a nullfunc frame with power save
368 * bit on so that AP will buffer the frames for us while we are not
369 * listening, then send probe requests to each channel and wait for
370 * the responses. After all channels are scanned, tune back to the
371 * original channel and send a nullfunc frame with power save bit
372 * off to trigger the AP to send us all the buffered frames.
374 * Note that while local->sw_scanning is true everything else but
375 * nullfunc frames and probe requests will be dropped in
376 * ieee80211_tx_h_check_assoc().
378 if (local
->ops
->sw_scan_start
)
379 local
->ops
->sw_scan_start(local_to_hw(local
));
381 mutex_lock(&local
->iflist_mtx
);
382 list_for_each_entry(sdata
, &local
->interfaces
, list
) {
383 if (!netif_running(sdata
->dev
))
386 /* disable beaconing */
387 if (sdata
->vif
.type
== NL80211_IFTYPE_AP
||
388 sdata
->vif
.type
== NL80211_IFTYPE_ADHOC
||
389 sdata
->vif
.type
== NL80211_IFTYPE_MESH_POINT
)
390 ieee80211_bss_info_change_notify(
391 sdata
, BSS_CHANGED_BEACON_ENABLED
);
393 if (sdata
->vif
.type
== NL80211_IFTYPE_STATION
) {
394 if (sdata
->u
.mgd
.flags
& IEEE80211_STA_ASSOCIATED
) {
395 netif_tx_stop_all_queues(sdata
->dev
);
396 ieee80211_scan_ps_enable(sdata
);
399 netif_tx_stop_all_queues(sdata
->dev
);
401 mutex_unlock(&local
->iflist_mtx
);
403 local
->scan_state
= SCAN_SET_CHANNEL
;
404 local
->scan_channel_idx
= 0;
406 netif_addr_lock_bh(local
->mdev
);
407 local
->filter_flags
|= FIF_BCN_PRBRESP_PROMISC
;
408 local
->ops
->configure_filter(local_to_hw(local
),
409 FIF_BCN_PRBRESP_PROMISC
,
410 &local
->filter_flags
,
411 local
->mdev
->mc_count
,
412 local
->mdev
->mc_list
);
413 netif_addr_unlock_bh(local
->mdev
);
415 /* TODO: start scan as soon as all nullfunc frames are ACKed */
416 queue_delayed_work(local
->hw
.workqueue
, &local
->scan_work
,
417 IEEE80211_CHANNEL_TIME
);
423 static int __ieee80211_start_scan(struct ieee80211_sub_if_data
*sdata
,
424 struct cfg80211_scan_request
*req
)
426 struct ieee80211_local
*local
= sdata
->local
;
427 struct ieee80211_if_managed
*ifmgd
= &sdata
->u
.mgd
;
433 if (local
->ops
->hw_scan
) {
437 ies
= kmalloc(2 + IEEE80211_MAX_SSID_LEN
+
438 local
->scan_ies_len
+ req
->ie_len
, GFP_KERNEL
);
442 ielen
= ieee80211_build_preq_ies(local
, ies
,
443 req
->ie
, req
->ie_len
);
444 local
->orig_ies
= req
->ie
;
445 local
->orig_ies_len
= req
->ie_len
;
450 local
->scan_req
= req
;
451 local
->scan_sdata
= sdata
;
453 if (req
!= &local
->int_scan_req
&&
454 sdata
->vif
.type
== NL80211_IFTYPE_STATION
&&
455 (ifmgd
->state
== IEEE80211_STA_MLME_DIRECT_PROBE
||
456 ifmgd
->state
== IEEE80211_STA_MLME_AUTHENTICATE
||
457 ifmgd
->state
== IEEE80211_STA_MLME_ASSOCIATE
)) {
458 /* actually wait for the assoc to finish/time out */
459 set_bit(IEEE80211_STA_REQ_SCAN
, &ifmgd
->request
);
463 if (local
->ops
->hw_scan
)
464 local
->hw_scanning
= true;
466 local
->sw_scanning
= true;
468 * Kicking off the scan need not be protected,
469 * only the scan variable stuff, since now
470 * local->scan_req is assigned and other callers
471 * will abort their scan attempts.
473 * This avoids getting a scan_mtx -> iflist_mtx
474 * dependency, so that the scan completed calls
475 * have more locking freedom.
477 mutex_unlock(&local
->scan_mtx
);
479 if (local
->ops
->hw_scan
)
480 rc
= local
->ops
->hw_scan(local_to_hw(local
),
483 rc
= ieee80211_start_sw_scan(local
);
485 mutex_lock(&local
->scan_mtx
);
488 if (local
->ops
->hw_scan
) {
489 local
->hw_scanning
= false;
490 ieee80211_restore_scan_ies(local
);
492 local
->sw_scanning
= false;
494 local
->scan_req
= NULL
;
495 local
->scan_sdata
= NULL
;
501 void ieee80211_scan_work(struct work_struct
*work
)
503 struct ieee80211_local
*local
=
504 container_of(work
, struct ieee80211_local
, scan_work
.work
);
505 struct ieee80211_sub_if_data
*sdata
= local
->scan_sdata
;
506 struct ieee80211_channel
*chan
;
508 unsigned long next_delay
= 0;
510 mutex_lock(&local
->scan_mtx
);
511 if (!sdata
|| !local
->scan_req
) {
512 mutex_unlock(&local
->scan_mtx
);
516 if (local
->scan_req
&& !(local
->sw_scanning
|| local
->hw_scanning
)) {
517 struct cfg80211_scan_request
*req
= local
->scan_req
;
520 local
->scan_req
= NULL
;
522 rc
= __ieee80211_start_scan(sdata
, req
);
523 mutex_unlock(&local
->scan_mtx
);
526 ieee80211_scan_completed(&local
->hw
, true);
530 mutex_unlock(&local
->scan_mtx
);
533 * Avoid re-scheduling when the sdata is going away.
535 if (!netif_running(sdata
->dev
)) {
536 ieee80211_scan_completed(&local
->hw
, true);
540 switch (local
->scan_state
) {
541 case SCAN_SET_CHANNEL
:
542 /* if no more bands/channels left, complete scan */
543 if (local
->scan_channel_idx
>= local
->scan_req
->n_channels
) {
544 ieee80211_scan_completed(&local
->hw
, false);
548 chan
= local
->scan_req
->channels
[local
->scan_channel_idx
];
550 if (chan
->flags
& IEEE80211_CHAN_DISABLED
||
551 (sdata
->vif
.type
== NL80211_IFTYPE_ADHOC
&&
552 chan
->flags
& IEEE80211_CHAN_NO_IBSS
))
556 local
->scan_channel
= chan
;
557 if (ieee80211_hw_config(local
,
558 IEEE80211_CONF_CHANGE_CHANNEL
))
562 /* advance state machine to next channel/band */
563 local
->scan_channel_idx
++;
568 next_delay
= IEEE80211_PROBE_DELAY
+
569 usecs_to_jiffies(local
->hw
.channel_change_time
);
570 local
->scan_state
= SCAN_SEND_PROBE
;
572 case SCAN_SEND_PROBE
:
573 next_delay
= IEEE80211_PASSIVE_CHANNEL_TIME
;
574 local
->scan_state
= SCAN_SET_CHANNEL
;
576 if (local
->scan_channel
->flags
& IEEE80211_CHAN_PASSIVE_SCAN
||
577 !local
->scan_req
->n_ssids
)
579 for (i
= 0; i
< local
->scan_req
->n_ssids
; i
++)
580 ieee80211_send_probe_req(
582 local
->scan_req
->ssids
[i
].ssid
,
583 local
->scan_req
->ssids
[i
].ssid_len
,
584 local
->scan_req
->ie
, local
->scan_req
->ie_len
);
585 next_delay
= IEEE80211_CHANNEL_TIME
;
589 queue_delayed_work(local
->hw
.workqueue
, &local
->scan_work
,
593 int ieee80211_request_scan(struct ieee80211_sub_if_data
*sdata
,
594 struct cfg80211_scan_request
*req
)
598 mutex_lock(&sdata
->local
->scan_mtx
);
599 res
= __ieee80211_start_scan(sdata
, req
);
600 mutex_unlock(&sdata
->local
->scan_mtx
);
605 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data
*sdata
,
606 const u8
*ssid
, u8 ssid_len
)
608 struct ieee80211_local
*local
= sdata
->local
;
611 mutex_lock(&local
->scan_mtx
);
617 memcpy(local
->int_scan_req
.ssids
[0].ssid
, ssid
, IEEE80211_MAX_SSID_LEN
);
618 local
->int_scan_req
.ssids
[0].ssid_len
= ssid_len
;
620 ret
= __ieee80211_start_scan(sdata
, &sdata
->local
->int_scan_req
);
622 mutex_unlock(&local
->scan_mtx
);