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;
66 enum cfg80211_signal_type sigtype = CFG80211_SIGNAL_TYPE_NONE;
69 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
70 sigtype = CFG80211_SIGNAL_TYPE_MBM;
71 signal = rx_status->signal * 100;
72 } else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) {
73 sigtype = CFG80211_SIGNAL_TYPE_UNSPEC;
74 signal = (rx_status->signal * 100) / local->hw.max_signal;
77 bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel,
78 mgmt, len, signal, sigtype,
84 bss->cbss.free_priv = ieee80211_rx_bss_free;
86 /* save the ERP value so that it is available at association time */
87 if (elems->erp_info && elems->erp_info_len >= 1) {
88 bss->erp_value = elems->erp_info[0];
89 bss->has_erp_value = 1;
93 struct ieee80211_tim_ie *tim_ie =
94 (struct ieee80211_tim_ie *)elems->tim;
95 bss->dtim_period = tim_ie->dtim_period;
98 /* set default value for buggy APs */
99 if (!elems->tim || bss->dtim_period == 0)
100 bss->dtim_period = 1;
102 bss->supp_rates_len = 0;
103 if (elems->supp_rates) {
104 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
105 if (clen > elems->supp_rates_len)
106 clen = elems->supp_rates_len;
107 memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates,
109 bss->supp_rates_len += clen;
111 if (elems->ext_supp_rates) {
112 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
113 if (clen > elems->ext_supp_rates_len)
114 clen = elems->ext_supp_rates_len;
115 memcpy(&bss->supp_rates[bss->supp_rates_len],
116 elems->ext_supp_rates, clen);
117 bss->supp_rates_len += clen;
120 bss->wmm_used = elems->wmm_param || elems->wmm_info;
123 bss->last_probe_resp = jiffies;
128 void ieee80211_rx_bss_remove(struct ieee80211_sub_if_data *sdata, u8 *bssid,
129 int freq, u8 *ssid, u8 ssid_len)
131 struct ieee80211_bss *bss;
132 struct ieee80211_local *local = sdata->local;
134 bss = ieee80211_rx_bss_get(local, bssid, freq, ssid, ssid_len);
136 cfg80211_unlink_bss(local->hw.wiphy, (void *)bss);
137 ieee80211_rx_bss_put(local, bss);
142 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
143 struct ieee80211_rx_status *rx_status)
145 struct ieee80211_mgmt *mgmt;
146 struct ieee80211_bss *bss;
148 struct ieee80211_channel *channel;
152 bool presp, beacon = false;
153 struct ieee802_11_elems elems;
156 return RX_DROP_UNUSABLE;
158 mgmt = (struct ieee80211_mgmt *) skb->data;
159 fc = mgmt->frame_control;
161 if (ieee80211_is_ctl(fc))
165 return RX_DROP_MONITOR;
167 presp = ieee80211_is_probe_resp(fc);
169 /* ignore ProbeResp to foreign address */
170 if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
171 return RX_DROP_MONITOR;
174 elements = mgmt->u.probe_resp.variable;
175 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
177 beacon = ieee80211_is_beacon(fc);
178 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
179 elements = mgmt->u.beacon.variable;
182 if (!presp && !beacon)
185 if (baselen > skb->len)
186 return RX_DROP_MONITOR;
188 ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
190 if (elems.ds_params && elems.ds_params_len == 1)
191 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
193 freq = rx_status->freq;
195 channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
197 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
198 return RX_DROP_MONITOR;
200 bss = ieee80211_bss_info_update(sdata->local, rx_status,
201 mgmt, skb->len, &elems,
204 ieee80211_rx_bss_put(sdata->local, bss);
210 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
212 struct ieee80211_local *local = hw_to_local(hw);
213 struct ieee80211_sub_if_data *sdata;
215 if (WARN_ON(!local->hw_scanning && !local->sw_scanning))
218 if (WARN_ON(!local->scan_req))
221 if (local->scan_req != &local->int_scan_req)
222 cfg80211_scan_done(local->scan_req, aborted);
223 local->scan_req = NULL;
225 local->last_scan_completed = jiffies;
227 if (local->hw_scanning) {
228 local->hw_scanning = false;
230 * Somebody might have requested channel change during scan
231 * that we won't have acted upon, try now. ieee80211_hw_config
232 * will set the flag based on actual changes.
234 ieee80211_hw_config(local, 0);
238 local->sw_scanning = false;
239 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
241 netif_tx_lock_bh(local->mdev);
242 netif_addr_lock(local->mdev);
243 local->filter_flags &= ~FIF_BCN_PRBRESP_PROMISC;
244 local->ops->configure_filter(local_to_hw(local),
245 FIF_BCN_PRBRESP_PROMISC,
246 &local->filter_flags,
247 local->mdev->mc_count,
248 local->mdev->mc_list);
250 netif_addr_unlock(local->mdev);
251 netif_tx_unlock_bh(local->mdev);
253 mutex_lock(&local->iflist_mtx);
254 list_for_each_entry(sdata, &local->interfaces, list) {
255 if (!netif_running(sdata->dev))
258 /* Tell AP we're back */
259 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
260 if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
261 ieee80211_send_nullfunc(local, sdata, 0);
262 netif_tx_wake_all_queues(sdata->dev);
265 netif_tx_wake_all_queues(sdata->dev);
267 /* re-enable beaconing */
268 if (sdata->vif.type == NL80211_IFTYPE_AP ||
269 sdata->vif.type == NL80211_IFTYPE_ADHOC ||
270 sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
271 ieee80211_if_config(sdata,
272 IEEE80211_IFCC_BEACON_ENABLED);
274 mutex_unlock(&local->iflist_mtx);
277 ieee80211_mlme_notify_scan_completed(local);
278 ieee80211_ibss_notify_scan_completed(local);
279 ieee80211_mesh_notify_scan_completed(local);
281 EXPORT_SYMBOL(ieee80211_scan_completed);
283 void ieee80211_scan_work(struct work_struct *work)
285 struct ieee80211_local *local =
286 container_of(work, struct ieee80211_local, scan_work.work);
287 struct ieee80211_sub_if_data *sdata = local->scan_sdata;
288 struct ieee80211_channel *chan;
290 unsigned long next_delay = 0;
293 * Avoid re-scheduling when the sdata is going away.
295 if (!netif_running(sdata->dev))
298 switch (local->scan_state) {
299 case SCAN_SET_CHANNEL:
300 /* if no more bands/channels left, complete scan */
301 if (local->scan_channel_idx >= local->scan_req->n_channels) {
302 ieee80211_scan_completed(local_to_hw(local), false);
306 chan = local->scan_req->channels[local->scan_channel_idx];
308 if (chan->flags & IEEE80211_CHAN_DISABLED ||
309 (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
310 chan->flags & IEEE80211_CHAN_NO_IBSS))
314 local->scan_channel = chan;
315 if (ieee80211_hw_config(local,
316 IEEE80211_CONF_CHANGE_CHANNEL))
320 /* advance state machine to next channel/band */
321 local->scan_channel_idx++;
326 next_delay = IEEE80211_PROBE_DELAY +
327 usecs_to_jiffies(local->hw.channel_change_time);
328 local->scan_state = SCAN_SEND_PROBE;
330 case SCAN_SEND_PROBE:
331 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
332 local->scan_state = SCAN_SET_CHANNEL;
334 if (local->scan_channel->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
335 !local->scan_req->n_ssids)
337 for (i = 0; i < local->scan_req->n_ssids; i++)
338 ieee80211_send_probe_req(
340 local->scan_req->ssids[i].ssid,
341 local->scan_req->ssids[i].ssid_len);
342 next_delay = IEEE80211_CHANNEL_TIME;
346 queue_delayed_work(local->hw.workqueue, &local->scan_work,
351 int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
352 struct cfg80211_scan_request *req)
354 struct ieee80211_local *local = scan_sdata->local;
355 struct ieee80211_sub_if_data *sdata;
360 if (local->scan_req && local->scan_req != req)
363 local->scan_req = req;
365 /* MLME-SCAN.request (page 118) page 144 (11.1.3.1)
366 * BSSType: INFRASTRUCTURE, INDEPENDENT, ANY_BSS
369 * ScanType: ACTIVE, PASSIVE
370 * ProbeDelay: delay (in microseconds) to be used prior to transmitting
371 * a Probe frame during active scanning
373 * MinChannelTime (>= ProbeDelay), in TU
374 * MaxChannelTime: (>= MinChannelTime), in TU
379 * ResultCode: SUCCESS, INVALID_PARAMETERS
382 if (local->sw_scanning || local->hw_scanning) {
383 if (local->scan_sdata == scan_sdata)
388 if (local->ops->hw_scan) {
391 local->hw_scanning = true;
392 rc = local->ops->hw_scan(local_to_hw(local), req);
394 local->hw_scanning = false;
397 local->scan_sdata = scan_sdata;
401 local->sw_scanning = true;
403 mutex_lock(&local->iflist_mtx);
404 list_for_each_entry(sdata, &local->interfaces, list) {
405 if (!netif_running(sdata->dev))
408 /* disable beaconing */
409 if (sdata->vif.type == NL80211_IFTYPE_AP ||
410 sdata->vif.type == NL80211_IFTYPE_ADHOC ||
411 sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
412 ieee80211_if_config(sdata,
413 IEEE80211_IFCC_BEACON_ENABLED);
415 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
416 if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
417 netif_tx_stop_all_queues(sdata->dev);
418 ieee80211_send_nullfunc(local, sdata, 1);
421 netif_tx_stop_all_queues(sdata->dev);
423 mutex_unlock(&local->iflist_mtx);
425 local->scan_state = SCAN_SET_CHANNEL;
426 local->scan_channel_idx = 0;
427 local->scan_sdata = scan_sdata;
428 local->scan_req = req;
430 netif_addr_lock_bh(local->mdev);
431 local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
432 local->ops->configure_filter(local_to_hw(local),
433 FIF_BCN_PRBRESP_PROMISC,
434 &local->filter_flags,
435 local->mdev->mc_count,
436 local->mdev->mc_list);
437 netif_addr_unlock_bh(local->mdev);
439 /* TODO: start scan as soon as all nullfunc frames are ACKed */
440 queue_delayed_work(local->hw.workqueue, &local->scan_work,
441 IEEE80211_CHANNEL_TIME);
447 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
448 struct cfg80211_scan_request *req)
450 struct ieee80211_local *local = sdata->local;
451 struct ieee80211_if_managed *ifmgd;
456 if (local->scan_req && local->scan_req != req)
459 local->scan_req = req;
461 if (sdata->vif.type != NL80211_IFTYPE_STATION)
462 return ieee80211_start_scan(sdata, req);
465 * STA has a state machine that might need to defer scanning
466 * while it's trying to associate/authenticate, therefore we
467 * queue it up to the state machine in that case.
470 if (local->sw_scanning || local->hw_scanning) {
471 if (local->scan_sdata == sdata)
476 ifmgd = &sdata->u.mgd;
477 set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
478 queue_work(local->hw.workqueue, &ifmgd->work);