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);
205 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
207 struct ieee80211_local *local = hw_to_local(hw);
208 struct ieee80211_sub_if_data *sdata;
210 if (WARN_ON(!local->hw_scanning && !local->sw_scanning))
213 if (WARN_ON(!local->scan_req))
216 if (local->scan_req != &local->int_scan_req)
217 cfg80211_scan_done(local->scan_req, aborted);
218 local->scan_req = NULL;
220 local->last_scan_completed = jiffies;
222 if (local->hw_scanning) {
223 local->hw_scanning = false;
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.
229 ieee80211_hw_config(local, 0);
233 local->sw_scanning = false;
234 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
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);
245 netif_addr_unlock(local->mdev);
246 netif_tx_unlock_bh(local->mdev);
248 mutex_lock(&local->iflist_mtx);
249 list_for_each_entry(sdata, &local->interfaces, list) {
250 if (!netif_running(sdata->dev))
253 /* Tell AP we're back */
254 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
255 if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
256 ieee80211_send_nullfunc(local, sdata, 0);
257 netif_tx_wake_all_queues(sdata->dev);
260 netif_tx_wake_all_queues(sdata->dev);
262 /* re-enable beaconing */
263 if (sdata->vif.type == NL80211_IFTYPE_AP ||
264 sdata->vif.type == NL80211_IFTYPE_ADHOC ||
265 sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
266 ieee80211_if_config(sdata,
267 IEEE80211_IFCC_BEACON_ENABLED);
269 mutex_unlock(&local->iflist_mtx);
272 ieee80211_mlme_notify_scan_completed(local);
273 ieee80211_ibss_notify_scan_completed(local);
274 ieee80211_mesh_notify_scan_completed(local);
276 EXPORT_SYMBOL(ieee80211_scan_completed);
278 void ieee80211_scan_work(struct work_struct *work)
280 struct ieee80211_local *local =
281 container_of(work, struct ieee80211_local, scan_work.work);
282 struct ieee80211_sub_if_data *sdata = local->scan_sdata;
283 struct ieee80211_channel *chan;
285 unsigned long next_delay = 0;
288 * Avoid re-scheduling when the sdata is going away.
290 if (!netif_running(sdata->dev))
293 switch (local->scan_state) {
294 case SCAN_SET_CHANNEL:
295 /* if no more bands/channels left, complete scan */
296 if (local->scan_channel_idx >= local->scan_req->n_channels) {
297 ieee80211_scan_completed(local_to_hw(local), false);
301 chan = local->scan_req->channels[local->scan_channel_idx];
303 if (chan->flags & IEEE80211_CHAN_DISABLED ||
304 (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
305 chan->flags & IEEE80211_CHAN_NO_IBSS))
309 local->scan_channel = chan;
310 if (ieee80211_hw_config(local,
311 IEEE80211_CONF_CHANGE_CHANNEL))
315 /* advance state machine to next channel/band */
316 local->scan_channel_idx++;
321 next_delay = IEEE80211_PROBE_DELAY +
322 usecs_to_jiffies(local->hw.channel_change_time);
323 local->scan_state = SCAN_SEND_PROBE;
325 case SCAN_SEND_PROBE:
326 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
327 local->scan_state = SCAN_SET_CHANNEL;
329 if (local->scan_channel->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
330 !local->scan_req->n_ssids)
332 for (i = 0; i < local->scan_req->n_ssids; i++)
333 ieee80211_send_probe_req(
335 local->scan_req->ssids[i].ssid,
336 local->scan_req->ssids[i].ssid_len,
337 local->scan_req->ie, local->scan_req->ie_len);
338 next_delay = IEEE80211_CHANNEL_TIME;
342 queue_delayed_work(local->hw.workqueue, &local->scan_work,
347 int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
348 struct cfg80211_scan_request *req)
350 struct ieee80211_local *local = scan_sdata->local;
351 struct ieee80211_sub_if_data *sdata;
356 if (local->scan_req && local->scan_req != req)
359 local->scan_req = req;
361 /* MLME-SCAN.request (page 118) page 144 (11.1.3.1)
362 * BSSType: INFRASTRUCTURE, INDEPENDENT, ANY_BSS
365 * ScanType: ACTIVE, PASSIVE
366 * ProbeDelay: delay (in microseconds) to be used prior to transmitting
367 * a Probe frame during active scanning
369 * MinChannelTime (>= ProbeDelay), in TU
370 * MaxChannelTime: (>= MinChannelTime), in TU
375 * ResultCode: SUCCESS, INVALID_PARAMETERS
378 if (local->sw_scanning || local->hw_scanning) {
379 if (local->scan_sdata == scan_sdata)
384 if (local->ops->hw_scan) {
387 local->hw_scanning = true;
388 rc = local->ops->hw_scan(local_to_hw(local), req);
390 local->hw_scanning = false;
393 local->scan_sdata = scan_sdata;
397 local->sw_scanning = true;
399 mutex_lock(&local->iflist_mtx);
400 list_for_each_entry(sdata, &local->interfaces, list) {
401 if (!netif_running(sdata->dev))
404 /* disable beaconing */
405 if (sdata->vif.type == NL80211_IFTYPE_AP ||
406 sdata->vif.type == NL80211_IFTYPE_ADHOC ||
407 sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
408 ieee80211_if_config(sdata,
409 IEEE80211_IFCC_BEACON_ENABLED);
411 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
412 if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
413 netif_tx_stop_all_queues(sdata->dev);
414 ieee80211_send_nullfunc(local, sdata, 1);
417 netif_tx_stop_all_queues(sdata->dev);
419 mutex_unlock(&local->iflist_mtx);
421 local->scan_state = SCAN_SET_CHANNEL;
422 local->scan_channel_idx = 0;
423 local->scan_sdata = scan_sdata;
424 local->scan_req = req;
426 netif_addr_lock_bh(local->mdev);
427 local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
428 local->ops->configure_filter(local_to_hw(local),
429 FIF_BCN_PRBRESP_PROMISC,
430 &local->filter_flags,
431 local->mdev->mc_count,
432 local->mdev->mc_list);
433 netif_addr_unlock_bh(local->mdev);
435 /* TODO: start scan as soon as all nullfunc frames are ACKed */
436 queue_delayed_work(local->hw.workqueue, &local->scan_work,
437 IEEE80211_CHANNEL_TIME);
443 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
444 struct cfg80211_scan_request *req)
446 struct ieee80211_local *local = sdata->local;
447 struct ieee80211_if_managed *ifmgd;
452 if (local->scan_req && local->scan_req != req)
455 local->scan_req = req;
457 if (sdata->vif.type != NL80211_IFTYPE_STATION)
458 return ieee80211_start_scan(sdata, req);
461 * STA has a state machine that might need to defer scanning
462 * while it's trying to associate/authenticate, therefore we
463 * queue it up to the state machine in that case.
466 if (local->sw_scanning || local->hw_scanning) {
467 if (local->scan_sdata == sdata)
472 ifmgd = &sdata->u.mgd;
473 set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
474 queue_work(local->hw.workqueue, &ifmgd->work);