SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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
  22 #include "ieee80211_i.h"
  23 #include "driver-ops.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 / 8)
  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 ieee80211_rx_result
 124 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 125 {
 126         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 127         struct ieee80211_mgmt *mgmt;
 128         struct ieee80211_bss *bss;
 129         u8 *elements;
 130         struct ieee80211_channel *channel;
 131         size_t baselen;
 132         int freq;
 133         __le16 fc;
 134         bool presp, beacon = false;
 135         struct ieee802_11_elems elems;
 136
 137         if (skb->len < 2)
 138                 return RX_DROP_UNUSABLE;
 139
 140         mgmt = (struct ieee80211_mgmt *) skb->data;
 141         fc = mgmt->frame_control;
 142
 143         if (ieee80211_is_ctl(fc))
 144                 return RX_CONTINUE;
 145
 146         if (skb->len < 24)
 147                 return RX_DROP_MONITOR;
 148
 149         presp = ieee80211_is_probe_resp(fc);
 150         if (presp) {
 151                 /* ignore ProbeResp to foreign address */
 152                 if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
 153                         return RX_DROP_MONITOR;
 154
 155                 presp = true;
 156                 elements = mgmt->u.probe_resp.variable;
 157                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 158         } else {
 159                 beacon = ieee80211_is_beacon(fc);
 160                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 161                 elements = mgmt->u.beacon.variable;
 162         }
 163
 164         if (!presp && !beacon)
 165                 return RX_CONTINUE;
 166
 167         if (baselen > skb->len)
 168                 return RX_DROP_MONITOR;
 169
 170         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 171
 172         if (elems.ds_params && elems.ds_params_len == 1)
 173                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
 174         else
 175                 freq = rx_status->freq;
 176
 177         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 178
 179         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 180                 return RX_DROP_MONITOR;
 181
 182         bss = ieee80211_bss_info_update(sdata->local, rx_status,
 183                                         mgmt, skb->len, &elems,
 184                                         channel, beacon);
 185         if (bss)
 186                 ieee80211_rx_bss_put(sdata->local, bss);
 187
 188         dev_kfree_skb(skb);
 189         return RX_QUEUED;
 190 }
 191
 192 /*
 193  * inform AP that we will go to sleep so that it will buffer the frames
 194  * while we scan
 195  */
 196 static void ieee80211_scan_ps_enable(struct ieee80211_sub_if_data *sdata)
 197 {
 198         struct ieee80211_local *local = sdata->local;
 199         bool ps = false;
 200
 201         /* FIXME: what to do when local->pspolling is true? */
 202
 203         del_timer_sync(&local->dynamic_ps_timer);
 204         cancel_work_sync(&local->dynamic_ps_enable_work);
 205
 206         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
 207                 ps = true;
 208                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
 209                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 210         }
 211
 212         if (!ps || !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
 213                 /*
 214                  * If power save was enabled, no need to send a nullfunc
 215                  * frame because AP knows that we are sleeping. But if the
 216                  * hardware is creating the nullfunc frame for power save
 217                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
 218                  * enabled) and power save was enabled, the firmware just
 219                  * sent a null frame with power save disabled. So we need
 220                  * to send a new nullfunc frame to inform the AP that we
 221                  * are again sleeping.
 222                  */
 223                 ieee80211_send_nullfunc(local, sdata, 1);
 224 }
 225
 226 /* inform AP that we are awake again, unless power save is enabled */
 227 static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata)
 228 {
 229         struct ieee80211_local *local = sdata->local;
 230
 231         if (!local->ps_sdata)
 232                 ieee80211_send_nullfunc(local, sdata, 0);
 233         else {
 234                 /*
 235                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
 236                  * will send a nullfunc frame with the powersave bit set
 237                  * even though the AP already knows that we are sleeping.
 238                  * This could be avoided by sending a null frame with power
 239                  * save bit disabled before enabling the power save, but
 240                  * this doesn't gain anything.
 241                  *
 242                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
 243                  * to send a nullfunc frame because AP already knows that
 244                  * we are sleeping, let's just enable power save mode in
 245                  * hardware.
 246                  */
 247                 local->hw.conf.flags |= IEEE80211_CONF_PS;
 248                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 249         }
 250 }
 251
 252 static void ieee80211_restore_scan_ies(struct ieee80211_local *local)
 253 {
 254         kfree(local->scan_req->ie);
 255         local->scan_req->ie = local->orig_ies;
 256         local->scan_req->ie_len = local->orig_ies_len;
 257 }
 258
 259 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 260 {
 261         struct ieee80211_local *local = hw_to_local(hw);
 262         struct ieee80211_sub_if_data *sdata;
 263         bool was_hw_scan;
 264
 265         mutex_lock(&local->scan_mtx);
 266
 267         if (WARN_ON(!local->scanning)) {
 268                 mutex_unlock(&local->scan_mtx);
 269                 return;
 270         }
 271
 272         if (WARN_ON(!local->scan_req)) {
 273                 mutex_unlock(&local->scan_mtx);
 274                 return;
 275         }
 276
 277         if (test_bit(SCAN_HW_SCANNING, &local->scanning))
 278                 ieee80211_restore_scan_ies(local);
 279
 280         if (local->scan_req != local->int_scan_req)
 281                 cfg80211_scan_done(local->scan_req, aborted);
 282         local->scan_req = NULL;
 283
 284         was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 285         local->scanning = 0;
 286         local->scan_channel = NULL;
 287
 288         /* we only have to protect scan_req and hw/sw scan */
 289         mutex_unlock(&local->scan_mtx);
 290
 291         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 292         if (was_hw_scan)
 293                 goto done;
 294
 295         ieee80211_configure_filter(local);
 296
 297         drv_sw_scan_complete(local);
 298
 299         mutex_lock(&local->iflist_mtx);
 300         list_for_each_entry(sdata, &local->interfaces, list) {
 301                 if (!netif_running(sdata->dev))
 302                         continue;
 303
 304                 /* Tell AP we're back */
 305                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 306                         if (sdata->u.mgd.associated) {
 307                                 ieee80211_scan_ps_disable(sdata);
 308                                 netif_tx_wake_all_queues(sdata->dev);
 309                         }
 310                 } else
 311                         netif_tx_wake_all_queues(sdata->dev);
 312
 313                 /* re-enable beaconing */
 314                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 315                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 316                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 317                         ieee80211_bss_info_change_notify(
 318                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 319         }
 320         mutex_unlock(&local->iflist_mtx);
 321
 322  done:
 323         ieee80211_recalc_idle(local);
 324         ieee80211_mlme_notify_scan_completed(local);
 325         ieee80211_ibss_notify_scan_completed(local);
 326         ieee80211_mesh_notify_scan_completed(local);
 327 }
 328 EXPORT_SYMBOL(ieee80211_scan_completed);
 329
 330 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 331 {
 332         struct ieee80211_sub_if_data *sdata;
 333
 334         /*
 335          * Hardware/driver doesn't support hw_scan, so use software
 336          * scanning instead. First send a nullfunc frame with power save
 337          * bit on so that AP will buffer the frames for us while we are not
 338          * listening, then send probe requests to each channel and wait for
 339          * the responses. After all channels are scanned, tune back to the
 340          * original channel and send a nullfunc frame with power save bit
 341          * off to trigger the AP to send us all the buffered frames.
 342          *
 343          * Note that while local->sw_scanning is true everything else but
 344          * nullfunc frames and probe requests will be dropped in
 345          * ieee80211_tx_h_check_assoc().
 346          */
 347         drv_sw_scan_start(local);
 348
 349         mutex_lock(&local->iflist_mtx);
 350         list_for_each_entry(sdata, &local->interfaces, list) {
 351                 if (!netif_running(sdata->dev))
 352                         continue;
 353
 354                 /* disable beaconing */
 355                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 356                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 357                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 358                         ieee80211_bss_info_change_notify(
 359                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 360
 361                 /*
 362                  * only handle non-STA interfaces here, STA interfaces
 363                  * are handled in the scan state machine
 364                  */
 365                 if (sdata->vif.type != NL80211_IFTYPE_STATION)
 366                         netif_tx_stop_all_queues(sdata->dev);
 367         }
 368         mutex_unlock(&local->iflist_mtx);
 369
 370         local->next_scan_state = SCAN_DECISION;
 371         local->scan_channel_idx = 0;
 372
 373         ieee80211_configure_filter(local);
 374
 375         /* TODO: start scan as soon as all nullfunc frames are ACKed */
 376         ieee80211_queue_delayed_work(&local->hw,
 377                                      &local->scan_work,
 378                                      IEEE80211_CHANNEL_TIME);
 379
 380         return 0;
 381 }
 382
 383
 384 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 385                                   struct cfg80211_scan_request *req)
 386 {
 387         struct ieee80211_local *local = sdata->local;
 388         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 389         int rc;
 390
 391         if (local->scan_req)
 392                 return -EBUSY;
 393
 394         if (local->ops->hw_scan) {
 395                 u8 *ies;
 396                 int ielen;
 397
 398                 ies = kmalloc(2 + IEEE80211_MAX_SSID_LEN +
 399                               local->scan_ies_len + req->ie_len, GFP_KERNEL);
 400                 if (!ies)
 401                         return -ENOMEM;
 402
 403                 ielen = ieee80211_build_preq_ies(local, ies,
 404                                                  req->ie, req->ie_len);
 405                 local->orig_ies = req->ie;
 406                 local->orig_ies_len = req->ie_len;
 407                 req->ie = ies;
 408                 req->ie_len = ielen;
 409         }
 410
 411         local->scan_req = req;
 412         local->scan_sdata = sdata;
 413
 414         if (req != local->int_scan_req &&
 415             sdata->vif.type == NL80211_IFTYPE_STATION &&
 416             !list_empty(&ifmgd->work_list)) {
 417                 /* actually wait for the work it's doing to finish/time out */
 418                 set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
 419                 return 0;
 420         }
 421
 422         if (local->ops->hw_scan)
 423                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 424         else
 425                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 426         /*
 427          * Kicking off the scan need not be protected,
 428          * only the scan variable stuff, since now
 429          * local->scan_req is assigned and other callers
 430          * will abort their scan attempts.
 431          *
 432          * This avoids getting a scan_mtx -> iflist_mtx
 433          * dependency, so that the scan completed calls
 434          * have more locking freedom.
 435          */
 436
 437         ieee80211_recalc_idle(local);
 438         mutex_unlock(&local->scan_mtx);
 439
 440         if (local->ops->hw_scan)
 441                 rc = drv_hw_scan(local, local->scan_req);
 442         else
 443                 rc = ieee80211_start_sw_scan(local);
 444
 445         mutex_lock(&local->scan_mtx);
 446
 447         if (rc) {
 448                 if (local->ops->hw_scan)
 449                         ieee80211_restore_scan_ies(local);
 450                 local->scanning = 0;
 451
 452                 ieee80211_recalc_idle(local);
 453
 454                 local->scan_req = NULL;
 455                 local->scan_sdata = NULL;
 456         }
 457
 458         return rc;
 459 }
 460
 461 static int ieee80211_scan_state_decision(struct ieee80211_local *local,
 462                                          unsigned long *next_delay)
 463 {
 464         bool associated = false;
 465         struct ieee80211_sub_if_data *sdata;
 466
 467         /* if no more bands/channels left, complete scan and advance to the idle state */
 468         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 469                 ieee80211_scan_completed(&local->hw, false);
 470                 return 1;
 471         }
 472
 473         /* check if at least one STA interface is associated */
 474         mutex_lock(&local->iflist_mtx);
 475         list_for_each_entry(sdata, &local->interfaces, list) {
 476                 if (!netif_running(sdata->dev))
 477                         continue;
 478
 479                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 480                         if (sdata->u.mgd.associated) {
 481                                 associated = true;
 482                                 break;
 483                         }
 484                 }
 485         }
 486         mutex_unlock(&local->iflist_mtx);
 487
 488         if (local->scan_channel) {
 489                 /*
 490                  * we're currently scanning a different channel, let's
 491                  * switch back to the operating channel now if at least
 492                  * one interface is associated. Otherwise just scan the
 493                  * next channel
 494                  */
 495                 if (associated)
 496                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
 497                 else
 498                         local->next_scan_state = SCAN_SET_CHANNEL;
 499         } else {
 500                 /*
 501                  * we're on the operating channel currently, let's
 502                  * leave that channel now to scan another one
 503                  */
 504                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
 505         }
 506
 507         *next_delay = 0;
 508         return 0;
 509 }
 510
 511 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
 512                                                     unsigned long *next_delay)
 513 {
 514         struct ieee80211_sub_if_data *sdata;
 515
 516         /*
 517          * notify the AP about us leaving the channel and stop all STA interfaces
 518          */
 519         mutex_lock(&local->iflist_mtx);
 520         list_for_each_entry(sdata, &local->interfaces, list) {
 521                 if (!netif_running(sdata->dev))
 522                         continue;
 523
 524                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 525                         netif_tx_stop_all_queues(sdata->dev);
 526                         if (sdata->u.mgd.associated)
 527                                 ieee80211_scan_ps_enable(sdata);
 528                 }
 529         }
 530         mutex_unlock(&local->iflist_mtx);
 531
 532         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
 533
 534         /* advance to the next channel to be scanned */
 535         *next_delay = HZ / 10;
 536         local->next_scan_state = SCAN_SET_CHANNEL;
 537 }
 538
 539 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
 540                                                     unsigned long *next_delay)
 541 {
 542         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 543
 544         /* switch back to the operating channel */
 545         local->scan_channel = NULL;
 546         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 547
 548         /*
 549          * notify the AP about us being back and restart all STA interfaces
 550          */
 551         mutex_lock(&local->iflist_mtx);
 552         list_for_each_entry(sdata, &local->interfaces, list) {
 553                 if (!netif_running(sdata->dev))
 554                         continue;
 555
 556                 /* Tell AP we're back */
 557                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 558                         if (sdata->u.mgd.associated)
 559                                 ieee80211_scan_ps_disable(sdata);
 560                         netif_tx_wake_all_queues(sdata->dev);
 561                 }
 562         }
 563         mutex_unlock(&local->iflist_mtx);
 564
 565         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
 566
 567         *next_delay = HZ / 5;
 568         local->next_scan_state = SCAN_DECISION;
 569 }
 570
 571 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 572                                              unsigned long *next_delay)
 573 {
 574         int skip;
 575         struct ieee80211_channel *chan;
 576         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 577
 578         skip = 0;
 579         chan = local->scan_req->channels[local->scan_channel_idx];
 580
 581         if (chan->flags & IEEE80211_CHAN_DISABLED ||
 582             (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
 583              chan->flags & IEEE80211_CHAN_NO_IBSS))
 584                 skip = 1;
 585
 586         if (!skip) {
 587                 local->scan_channel = chan;
 588                 if (ieee80211_hw_config(local,
 589                                         IEEE80211_CONF_CHANGE_CHANNEL))
 590                         skip = 1;
 591         }
 592
 593         /* advance state machine to next channel/band */
 594         local->scan_channel_idx++;
 595
 596         if (skip) {
 597                 /* if we skip this channel return to the decision state */
 598                 local->next_scan_state = SCAN_DECISION;
 599                 return;
 600         }
 601
 602         /*
 603          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 604          * (which unfortunately doesn't say _why_ step a) is done,
 605          * but it waits for the probe delay or until a frame is
 606          * received - and the received frame would update the NAV).
 607          * For now, we do not support waiting until a frame is
 608          * received.
 609          *
 610          * In any case, it is not necessary for a passive scan.
 611          */
 612         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 613             !local->scan_req->n_ssids) {
 614                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 615                 local->next_scan_state = SCAN_DECISION;
 616                 return;
 617         }
 618
 619         /* active scan, send probes */
 620         *next_delay = IEEE80211_PROBE_DELAY;
 621         local->next_scan_state = SCAN_SEND_PROBE;
 622 }
 623
 624 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 625                                             unsigned long *next_delay)
 626 {
 627         int i;
 628         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 629
 630         for (i = 0; i < local->scan_req->n_ssids; i++)
 631                 ieee80211_send_probe_req(
 632                         sdata, NULL,
 633                         local->scan_req->ssids[i].ssid,
 634                         local->scan_req->ssids[i].ssid_len,
 635                         local->scan_req->ie, local->scan_req->ie_len);
 636
 637         /*
 638          * After sending probe requests, wait for probe responses
 639          * on the channel.
 640          */
 641         *next_delay = IEEE80211_CHANNEL_TIME;
 642         local->next_scan_state = SCAN_DECISION;
 643 }
 644
 645 void ieee80211_scan_work(struct work_struct *work)
 646 {
 647         struct ieee80211_local *local =
 648                 container_of(work, struct ieee80211_local, scan_work.work);
 649         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 650         unsigned long next_delay = 0;
 651
 652         mutex_lock(&local->scan_mtx);
 653         if (!sdata || !local->scan_req) {
 654                 mutex_unlock(&local->scan_mtx);
 655                 return;
 656         }
 657
 658         if (local->scan_req && !local->scanning) {
 659                 struct cfg80211_scan_request *req = local->scan_req;
 660                 int rc;
 661
 662                 local->scan_req = NULL;
 663
 664                 rc = __ieee80211_start_scan(sdata, req);
 665                 mutex_unlock(&local->scan_mtx);
 666
 667                 if (rc)
 668                         ieee80211_scan_completed(&local->hw, true);
 669                 return;
 670         }
 671
 672         mutex_unlock(&local->scan_mtx);
 673
 674         /*
 675          * Avoid re-scheduling when the sdata is going away.
 676          */
 677         if (!netif_running(sdata->dev)) {
 678                 ieee80211_scan_completed(&local->hw, true);
 679                 return;
 680         }
 681
 682         /*
 683          * as long as no delay is required advance immediately
 684          * without scheduling a new work
 685          */
 686         do {
 687                 switch (local->next_scan_state) {
 688                 case SCAN_DECISION:
 689                         if (ieee80211_scan_state_decision(local, &next_delay))
 690                                 return;
 691                         break;
 692                 case SCAN_SET_CHANNEL:
 693                         ieee80211_scan_state_set_channel(local, &next_delay);
 694                         break;
 695                 case SCAN_SEND_PROBE:
 696                         ieee80211_scan_state_send_probe(local, &next_delay);
 697                         break;
 698                 case SCAN_LEAVE_OPER_CHANNEL:
 699                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
 700                         break;
 701                 case SCAN_ENTER_OPER_CHANNEL:
 702                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 703                         break;
 704                 }
 705         } while (next_delay == 0);
 706
 707         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 708 }
 709
 710 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 711                            struct cfg80211_scan_request *req)
 712 {
 713         int res;
 714
 715         mutex_lock(&sdata->local->scan_mtx);
 716         res = __ieee80211_start_scan(sdata, req);
 717         mutex_unlock(&sdata->local->scan_mtx);
 718
 719         return res;
 720 }
 721
 722 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 723                                     const u8 *ssid, u8 ssid_len)
 724 {
 725         struct ieee80211_local *local = sdata->local;
 726         int ret = -EBUSY;
 727
 728         mutex_lock(&local->scan_mtx);
 729
 730         /* busy scanning */
 731         if (local->scan_req)
 732                 goto unlock;
 733
 734         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 735         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 736
 737         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 738  unlock:
 739         mutex_unlock(&local->scan_mtx);
 740         return ret;
 741 }
 742
 743 void ieee80211_scan_cancel(struct ieee80211_local *local)
 744 {
 745         bool swscan;
 746
 747         cancel_delayed_work_sync(&local->scan_work);
 748
 749         /*
 750          * Only call this function when a scan can't be
 751          * queued -- mostly at suspend under RTNL.
 752          */
 753         mutex_lock(&local->scan_mtx);
 754         swscan = test_bit(SCAN_SW_SCANNING, &local->scanning);
 755         mutex_unlock(&local->scan_mtx);
 756
 757         if (swscan)
 758                 ieee80211_scan_completed(&local->hw, true);
 759 }