mac80211: Add software scan notifiers
[linux-2.6.git] / net / mac80211 / scan.c
1 /*
2  * Scanning implementation
3  *
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>
9  *
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.
13  */
14
15 /* TODO: figure out how to avoid that the "current BSS" expires */
16
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>
22
23 #include "ieee80211_i.h"
24 #include "mesh.h"
25
26 #define IEEE80211_PROBE_DELAY (HZ / 33)
27 #define IEEE80211_CHANNEL_TIME (HZ / 33)
28 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)
29
30 struct ieee80211_bss *
31 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
32                      u8 *ssid, u8 ssid_len)
33 {
34         return (void *)cfg80211_get_bss(local->hw.wiphy,
35                                         ieee80211_get_channel(local->hw.wiphy,
36                                                               freq),
37                                         bssid, ssid, ssid_len,
38                                         0, 0);
39 }
40
41 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
42 {
43         struct ieee80211_bss *bss = (void *)cbss;
44
45         kfree(bss_mesh_id(bss));
46         kfree(bss_mesh_cfg(bss));
47 }
48
49 void ieee80211_rx_bss_put(struct ieee80211_local *local,
50                           struct ieee80211_bss *bss)
51 {
52         cfg80211_put_bss((struct cfg80211_bss *)bss);
53 }
54
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,
59                           size_t len,
60                           struct ieee802_11_elems *elems,
61                           struct ieee80211_channel *channel,
62                           bool beacon)
63 {
64         struct ieee80211_bss *bss;
65         int clen;
66         s32 signal = 0;
67
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;
72
73         bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel,
74                                                 mgmt, len, signal, GFP_ATOMIC);
75
76         if (!bss)
77                 return NULL;
78
79         bss->cbss.free_priv = ieee80211_rx_bss_free;
80
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;
85         }
86
87         if (elems->tim) {
88                 struct ieee80211_tim_ie *tim_ie =
89                         (struct ieee80211_tim_ie *)elems->tim;
90                 bss->dtim_period = tim_ie->dtim_period;
91         }
92
93         /* set default value for buggy APs */
94         if (!elems->tim || bss->dtim_period == 0)
95                 bss->dtim_period = 1;
96
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,
103                        clen);
104                 bss->supp_rates_len += clen;
105         }
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;
113         }
114
115         bss->wmm_used = elems->wmm_param || elems->wmm_info;
116
117         if (!beacon)
118                 bss->last_probe_resp = jiffies;
119
120         return bss;
121 }
122
123 void ieee80211_rx_bss_remove(struct ieee80211_sub_if_data *sdata, u8 *bssid,
124                              int freq, u8 *ssid, u8 ssid_len)
125 {
126         struct ieee80211_bss *bss;
127         struct ieee80211_local *local = sdata->local;
128
129         bss = ieee80211_rx_bss_get(local, bssid, freq, ssid, ssid_len);
130         if (bss) {
131                 cfg80211_unlink_bss(local->hw.wiphy, (void *)bss);
132                 ieee80211_rx_bss_put(local, bss);
133         }
134 }
135
136 ieee80211_rx_result
137 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
138                   struct ieee80211_rx_status *rx_status)
139 {
140         struct ieee80211_mgmt *mgmt;
141         struct ieee80211_bss *bss;
142         u8 *elements;
143         struct ieee80211_channel *channel;
144         size_t baselen;
145         int freq;
146         __le16 fc;
147         bool presp, beacon = false;
148         struct ieee802_11_elems elems;
149
150         if (skb->len < 2)
151                 return RX_DROP_UNUSABLE;
152
153         mgmt = (struct ieee80211_mgmt *) skb->data;
154         fc = mgmt->frame_control;
155
156         if (ieee80211_is_ctl(fc))
157                 return RX_CONTINUE;
158
159         if (skb->len < 24)
160                 return RX_DROP_MONITOR;
161
162         presp = ieee80211_is_probe_resp(fc);
163         if (presp) {
164                 /* ignore ProbeResp to foreign address */
165                 if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
166                         return RX_DROP_MONITOR;
167
168                 presp = true;
169                 elements = mgmt->u.probe_resp.variable;
170                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
171         } else {
172                 beacon = ieee80211_is_beacon(fc);
173                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
174                 elements = mgmt->u.beacon.variable;
175         }
176
177         if (!presp && !beacon)
178                 return RX_CONTINUE;
179
180         if (baselen > skb->len)
181                 return RX_DROP_MONITOR;
182
183         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
184
185         if (elems.ds_params && elems.ds_params_len == 1)
186                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
187         else
188                 freq = rx_status->freq;
189
190         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
191
192         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
193                 return RX_DROP_MONITOR;
194
195         bss = ieee80211_bss_info_update(sdata->local, rx_status,
196                                         mgmt, skb->len, &elems,
197                                         channel, beacon);
198         if (bss)
199                 ieee80211_rx_bss_put(sdata->local, bss);
200
201         dev_kfree_skb(skb);
202         return RX_QUEUED;
203 }
204
205 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
206 {
207         struct ieee80211_local *local = hw_to_local(hw);
208         struct ieee80211_sub_if_data *sdata;
209
210         if (WARN_ON(!local->hw_scanning && !local->sw_scanning))
211                 return;
212
213         if (WARN_ON(!local->scan_req))
214                 return;
215
216         if (local->scan_req != &local->int_scan_req)
217                 cfg80211_scan_done(local->scan_req, aborted);
218         local->scan_req = NULL;
219
220         local->last_scan_completed = jiffies;
221
222         if (local->hw_scanning) {
223                 local->hw_scanning = false;
224                 /*
225                  * Somebody might have requested channel change during scan
226                  * that we won't have acted upon, try now. ieee80211_hw_config
227                  * will set the flag based on actual changes.
228                  */
229                 ieee80211_hw_config(local, 0);
230                 goto done;
231         }
232
233         local->sw_scanning = false;
234         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
235
236         netif_tx_lock_bh(local->mdev);
237         netif_addr_lock(local->mdev);
238         local->filter_flags &= ~FIF_BCN_PRBRESP_PROMISC;
239         local->ops->configure_filter(local_to_hw(local),
240                                      FIF_BCN_PRBRESP_PROMISC,
241                                      &local->filter_flags,
242                                      local->mdev->mc_count,
243                                      local->mdev->mc_list);
244
245         netif_addr_unlock(local->mdev);
246         netif_tx_unlock_bh(local->mdev);
247
248         if (local->ops->sw_scan_complete)
249                 local->ops->sw_scan_complete(local_to_hw(local));
250
251         mutex_lock(&local->iflist_mtx);
252         list_for_each_entry(sdata, &local->interfaces, list) {
253                 if (!netif_running(sdata->dev))
254                         continue;
255
256                 /* Tell AP we're back */
257                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
258                         if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
259                                 ieee80211_send_nullfunc(local, sdata, 0);
260                                 netif_tx_wake_all_queues(sdata->dev);
261                         }
262                 } else
263                         netif_tx_wake_all_queues(sdata->dev);
264
265                 /* re-enable beaconing */
266                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
267                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
268                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
269                         ieee80211_if_config(sdata,
270                                             IEEE80211_IFCC_BEACON_ENABLED);
271         }
272         mutex_unlock(&local->iflist_mtx);
273
274  done:
275         ieee80211_mlme_notify_scan_completed(local);
276         ieee80211_ibss_notify_scan_completed(local);
277         ieee80211_mesh_notify_scan_completed(local);
278 }
279 EXPORT_SYMBOL(ieee80211_scan_completed);
280
281 void ieee80211_scan_work(struct work_struct *work)
282 {
283         struct ieee80211_local *local =
284                 container_of(work, struct ieee80211_local, scan_work.work);
285         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
286         struct ieee80211_channel *chan;
287         int skip, i;
288         unsigned long next_delay = 0;
289
290         /*
291          * Avoid re-scheduling when the sdata is going away.
292          */
293         if (!netif_running(sdata->dev))
294                 return;
295
296         switch (local->scan_state) {
297         case SCAN_SET_CHANNEL:
298                 /* if no more bands/channels left, complete scan */
299                 if (local->scan_channel_idx >= local->scan_req->n_channels) {
300                         ieee80211_scan_completed(local_to_hw(local), false);
301                         return;
302                 }
303                 skip = 0;
304                 chan = local->scan_req->channels[local->scan_channel_idx];
305
306                 if (chan->flags & IEEE80211_CHAN_DISABLED ||
307                     (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
308                      chan->flags & IEEE80211_CHAN_NO_IBSS))
309                         skip = 1;
310
311                 if (!skip) {
312                         local->scan_channel = chan;
313                         if (ieee80211_hw_config(local,
314                                                 IEEE80211_CONF_CHANGE_CHANNEL))
315                                 skip = 1;
316                 }
317
318                 /* advance state machine to next channel/band */
319                 local->scan_channel_idx++;
320
321                 if (skip)
322                         break;
323
324                 next_delay = IEEE80211_PROBE_DELAY +
325                              usecs_to_jiffies(local->hw.channel_change_time);
326                 local->scan_state = SCAN_SEND_PROBE;
327                 break;
328         case SCAN_SEND_PROBE:
329                 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
330                 local->scan_state = SCAN_SET_CHANNEL;
331
332                 if (local->scan_channel->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
333                     !local->scan_req->n_ssids)
334                         break;
335                 for (i = 0; i < local->scan_req->n_ssids; i++)
336                         ieee80211_send_probe_req(
337                                 sdata, NULL,
338                                 local->scan_req->ssids[i].ssid,
339                                 local->scan_req->ssids[i].ssid_len,
340                                 local->scan_req->ie, local->scan_req->ie_len);
341                 next_delay = IEEE80211_CHANNEL_TIME;
342                 break;
343         }
344
345         queue_delayed_work(local->hw.workqueue, &local->scan_work,
346                            next_delay);
347 }
348
349
350 int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
351                          struct cfg80211_scan_request *req)
352 {
353         struct ieee80211_local *local = scan_sdata->local;
354         struct ieee80211_sub_if_data *sdata;
355
356         if (!req)
357                 return -EINVAL;
358
359         if (local->scan_req && local->scan_req != req)
360                 return -EBUSY;
361
362         local->scan_req = req;
363
364         /* MLME-SCAN.request (page 118)  page 144 (11.1.3.1)
365          * BSSType: INFRASTRUCTURE, INDEPENDENT, ANY_BSS
366          * BSSID: MACAddress
367          * SSID
368          * ScanType: ACTIVE, PASSIVE
369          * ProbeDelay: delay (in microseconds) to be used prior to transmitting
370          *    a Probe frame during active scanning
371          * ChannelList
372          * MinChannelTime (>= ProbeDelay), in TU
373          * MaxChannelTime: (>= MinChannelTime), in TU
374          */
375
376          /* MLME-SCAN.confirm
377           * BSSDescriptionSet
378           * ResultCode: SUCCESS, INVALID_PARAMETERS
379          */
380
381         if (local->sw_scanning || local->hw_scanning) {
382                 if (local->scan_sdata == scan_sdata)
383                         return 0;
384                 return -EBUSY;
385         }
386
387         if (local->ops->hw_scan) {
388                 int rc;
389
390                 local->hw_scanning = true;
391                 rc = local->ops->hw_scan(local_to_hw(local), req);
392                 if (rc) {
393                         local->hw_scanning = false;
394                         return rc;
395                 }
396                 local->scan_sdata = scan_sdata;
397                 return 0;
398         }
399
400         local->sw_scanning = true;
401         if (local->ops->sw_scan_start)
402                 local->ops->sw_scan_start(local_to_hw(local));
403
404         mutex_lock(&local->iflist_mtx);
405         list_for_each_entry(sdata, &local->interfaces, list) {
406                 if (!netif_running(sdata->dev))
407                         continue;
408
409                 /* disable beaconing */
410                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
411                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
412                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
413                         ieee80211_if_config(sdata,
414                                             IEEE80211_IFCC_BEACON_ENABLED);
415
416                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
417                         if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
418                                 netif_tx_stop_all_queues(sdata->dev);
419                                 ieee80211_send_nullfunc(local, sdata, 1);
420                         }
421                 } else
422                         netif_tx_stop_all_queues(sdata->dev);
423         }
424         mutex_unlock(&local->iflist_mtx);
425
426         local->scan_state = SCAN_SET_CHANNEL;
427         local->scan_channel_idx = 0;
428         local->scan_sdata = scan_sdata;
429         local->scan_req = req;
430
431         netif_addr_lock_bh(local->mdev);
432         local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
433         local->ops->configure_filter(local_to_hw(local),
434                                      FIF_BCN_PRBRESP_PROMISC,
435                                      &local->filter_flags,
436                                      local->mdev->mc_count,
437                                      local->mdev->mc_list);
438         netif_addr_unlock_bh(local->mdev);
439
440         /* TODO: start scan as soon as all nullfunc frames are ACKed */
441         queue_delayed_work(local->hw.workqueue, &local->scan_work,
442                            IEEE80211_CHANNEL_TIME);
443
444         return 0;
445 }
446
447
448 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
449                            struct cfg80211_scan_request *req)
450 {
451         struct ieee80211_local *local = sdata->local;
452         struct ieee80211_if_managed *ifmgd;
453
454         if (!req)
455                 return -EINVAL;
456
457         if (local->scan_req && local->scan_req != req)
458                 return -EBUSY;
459
460         local->scan_req = req;
461
462         if (sdata->vif.type != NL80211_IFTYPE_STATION)
463                 return ieee80211_start_scan(sdata, req);
464
465         /*
466          * STA has a state machine that might need to defer scanning
467          * while it's trying to associate/authenticate, therefore we
468          * queue it up to the state machine in that case.
469          */
470
471         if (local->sw_scanning || local->hw_scanning) {
472                 if (local->scan_sdata == sdata)
473                         return 0;
474                 return -EBUSY;
475         }
476
477         ifmgd = &sdata->u.mgd;
478         set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
479         queue_work(local->hw.workqueue, &ifmgd->work);
480
481         return 0;
482 }