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 #include <linux/wireless.h>
  16 #include <linux/if_arp.h>
  17 #include <linux/rtnetlink.h>
  18 #include <net/mac80211.h>
  19
  20 #include "ieee80211_i.h"
  21 #include "driver-ops.h"
  22 #include "mesh.h"
  23
  24 #define IEEE80211_PROBE_DELAY (HZ / 33)
  25 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  26 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
  27
  28 struct ieee80211_bss *
  29 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
  30                      u8 *ssid, u8 ssid_len)
  31 {
  32         return (void *)cfg80211_get_bss(local->hw.wiphy,
  33                                         ieee80211_get_channel(local->hw.wiphy,
  34                                                               freq),
  35                                         bssid, ssid, ssid_len,
  36                                         0, 0);
  37 }
  38
  39 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
  40 {
  41         struct ieee80211_bss *bss = (void *)cbss;
  42
  43         kfree(bss_mesh_id(bss));
  44         kfree(bss_mesh_cfg(bss));
  45 }
  46
  47 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  48                           struct ieee80211_bss *bss)
  49 {
  50         cfg80211_put_bss((struct cfg80211_bss *)bss);
  51 }
  52
  53 struct ieee80211_bss *
  54 ieee80211_bss_info_update(struct ieee80211_local *local,
  55                           struct ieee80211_rx_status *rx_status,
  56                           struct ieee80211_mgmt *mgmt,
  57                           size_t len,
  58                           struct ieee802_11_elems *elems,
  59                           struct ieee80211_channel *channel,
  60                           bool beacon)
  61 {
  62         struct ieee80211_bss *bss;
  63         int clen;
  64         s32 signal = 0;
  65
  66         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  67                 signal = rx_status->signal * 100;
  68         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  69                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  70
  71         bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  72                                                 mgmt, len, signal, GFP_ATOMIC);
  73
  74         if (!bss)
  75                 return NULL;
  76
  77         bss->cbss.free_priv = ieee80211_rx_bss_free;
  78
  79         /* save the ERP value so that it is available at association time */
  80         if (elems->erp_info && elems->erp_info_len >= 1) {
  81                 bss->erp_value = elems->erp_info[0];
  82                 bss->has_erp_value = 1;
  83         }
  84
  85         if (elems->tim) {
  86                 struct ieee80211_tim_ie *tim_ie =
  87                         (struct ieee80211_tim_ie *)elems->tim;
  88                 bss->dtim_period = tim_ie->dtim_period;
  89         }
  90
  91         /* set default value for buggy AP/no TIM element */
  92         if (bss->dtim_period == 0)
  93                 bss->dtim_period = 1;
  94
  95         bss->supp_rates_len = 0;
  96         if (elems->supp_rates) {
  97                 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
  98                 if (clen > elems->supp_rates_len)
  99                         clen = elems->supp_rates_len;
 100                 memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates,
 101                        clen);
 102                 bss->supp_rates_len += clen;
 103         }
 104         if (elems->ext_supp_rates) {
 105                 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
 106                 if (clen > elems->ext_supp_rates_len)
 107                         clen = elems->ext_supp_rates_len;
 108                 memcpy(&bss->supp_rates[bss->supp_rates_len],
 109                        elems->ext_supp_rates, clen);
 110                 bss->supp_rates_len += clen;
 111         }
 112
 113         bss->wmm_used = elems->wmm_param || elems->wmm_info;
 114
 115         if (!beacon)
 116                 bss->last_probe_resp = jiffies;
 117
 118         return bss;
 119 }
 120
 121 ieee80211_rx_result
 122 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 123 {
 124         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 125         struct ieee80211_mgmt *mgmt;
 126         struct ieee80211_bss *bss;
 127         u8 *elements;
 128         struct ieee80211_channel *channel;
 129         size_t baselen;
 130         int freq;
 131         __le16 fc;
 132         bool presp, beacon = false;
 133         struct ieee802_11_elems elems;
 134
 135         if (skb->len < 2)
 136                 return RX_DROP_UNUSABLE;
 137
 138         mgmt = (struct ieee80211_mgmt *) skb->data;
 139         fc = mgmt->frame_control;
 140
 141         if (ieee80211_is_ctl(fc))
 142                 return RX_CONTINUE;
 143
 144         if (skb->len < 24)
 145                 return RX_DROP_MONITOR;
 146
 147         presp = ieee80211_is_probe_resp(fc);
 148         if (presp) {
 149                 /* ignore ProbeResp to foreign address */
 150                 if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
 151                         return RX_DROP_MONITOR;
 152
 153                 presp = true;
 154                 elements = mgmt->u.probe_resp.variable;
 155                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 156         } else {
 157                 beacon = ieee80211_is_beacon(fc);
 158                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 159                 elements = mgmt->u.beacon.variable;
 160         }
 161
 162         if (!presp && !beacon)
 163                 return RX_CONTINUE;
 164
 165         if (baselen > skb->len)
 166                 return RX_DROP_MONITOR;
 167
 168         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 169
 170         if (elems.ds_params && elems.ds_params_len == 1)
 171                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
 172         else
 173                 freq = rx_status->freq;
 174
 175         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 176
 177         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 178                 return RX_DROP_MONITOR;
 179
 180         bss = ieee80211_bss_info_update(sdata->local, rx_status,
 181                                         mgmt, skb->len, &elems,
 182                                         channel, beacon);
 183         if (bss)
 184                 ieee80211_rx_bss_put(sdata->local, bss);
 185
 186         dev_kfree_skb(skb);
 187         return RX_QUEUED;
 188 }
 189
 190 /*
 191  * inform AP that we will go to sleep so that it will buffer the frames
 192  * while we scan
 193  */
 194 static void ieee80211_scan_ps_enable(struct ieee80211_sub_if_data *sdata)
 195 {
 196         struct ieee80211_local *local = sdata->local;
 197         bool ps = false;
 198
 199         /* FIXME: what to do when local->pspolling is true? */
 200
 201         del_timer_sync(&local->dynamic_ps_timer);
 202         cancel_work_sync(&local->dynamic_ps_enable_work);
 203
 204         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
 205                 ps = true;
 206                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
 207                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 208         }
 209
 210         if (!ps || !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
 211                 /*
 212                  * If power save was enabled, no need to send a nullfunc
 213                  * frame because AP knows that we are sleeping. But if the
 214                  * hardware is creating the nullfunc frame for power save
 215                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
 216                  * enabled) and power save was enabled, the firmware just
 217                  * sent a null frame with power save disabled. So we need
 218                  * to send a new nullfunc frame to inform the AP that we
 219                  * are again sleeping.
 220                  */
 221                 ieee80211_send_nullfunc(local, sdata, 1);
 222 }
 223
 224 /* inform AP that we are awake again, unless power save is enabled */
 225 static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata)
 226 {
 227         struct ieee80211_local *local = sdata->local;
 228
 229         if (!local->ps_sdata)
 230                 ieee80211_send_nullfunc(local, sdata, 0);
 231         else {
 232                 /*
 233                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
 234                  * will send a nullfunc frame with the powersave bit set
 235                  * even though the AP already knows that we are sleeping.
 236                  * This could be avoided by sending a null frame with power
 237                  * save bit disabled before enabling the power save, but
 238                  * this doesn't gain anything.
 239                  *
 240                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
 241                  * to send a nullfunc frame because AP already knows that
 242                  * we are sleeping, let's just enable power save mode in
 243                  * hardware.
 244                  */
 245                 local->hw.conf.flags |= IEEE80211_CONF_PS;
 246                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 247         }
 248 }
 249
 250 static void ieee80211_restore_scan_ies(struct ieee80211_local *local)
 251 {
 252         kfree(local->scan_req->ie);
 253         local->scan_req->ie = local->orig_ies;
 254         local->scan_req->ie_len = local->orig_ies_len;
 255 }
 256
 257 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 258 {
 259         struct ieee80211_local *local = hw_to_local(hw);
 260         struct ieee80211_sub_if_data *sdata;
 261         bool was_hw_scan;
 262
 263         mutex_lock(&local->scan_mtx);
 264
 265         if (WARN_ON(!local->scanning)) {
 266                 mutex_unlock(&local->scan_mtx);
 267                 return;
 268         }
 269
 270         if (WARN_ON(!local->scan_req)) {
 271                 mutex_unlock(&local->scan_mtx);
 272                 return;
 273         }
 274
 275         if (test_bit(SCAN_HW_SCANNING, &local->scanning))
 276                 ieee80211_restore_scan_ies(local);
 277
 278         if (local->scan_req != local->int_scan_req)
 279                 cfg80211_scan_done(local->scan_req, aborted);
 280         local->scan_req = NULL;
 281         local->scan_sdata = NULL;
 282
 283         was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 284         local->scanning = 0;
 285         local->scan_channel = NULL;
 286
 287         /* we only have to protect scan_req and hw/sw scan */
 288         mutex_unlock(&local->scan_mtx);
 289
 290         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 291         if (was_hw_scan)
 292                 goto done;
 293
 294         ieee80211_configure_filter(local);
 295
 296         drv_sw_scan_complete(local);
 297
 298         mutex_lock(&local->iflist_mtx);
 299         list_for_each_entry(sdata, &local->interfaces, list) {
 300                 if (!netif_running(sdata->dev))
 301                         continue;
 302
 303                 /* Tell AP we're back */
 304                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 305                         if (sdata->u.mgd.associated) {
 306                                 ieee80211_scan_ps_disable(sdata);
 307                                 netif_wake_queue(sdata->dev);
 308                         }
 309                 } else
 310                         netif_wake_queue(sdata->dev);
 311
 312                 /* re-enable beaconing */
 313                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 314                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 315                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 316                         ieee80211_bss_info_change_notify(
 317                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 318         }
 319         mutex_unlock(&local->iflist_mtx);
 320
 321  done:
 322         ieee80211_recalc_idle(local);
 323         ieee80211_mlme_notify_scan_completed(local);
 324         ieee80211_ibss_notify_scan_completed(local);
 325         ieee80211_mesh_notify_scan_completed(local);
 326 }
 327 EXPORT_SYMBOL(ieee80211_scan_completed);
 328
 329 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 330 {
 331         struct ieee80211_sub_if_data *sdata;
 332
 333         /*
 334          * Hardware/driver doesn't support hw_scan, so use software
 335          * scanning instead. First send a nullfunc frame with power save
 336          * bit on so that AP will buffer the frames for us while we are not
 337          * listening, then send probe requests to each channel and wait for
 338          * the responses. After all channels are scanned, tune back to the
 339          * original channel and send a nullfunc frame with power save bit
 340          * off to trigger the AP to send us all the buffered frames.
 341          *
 342          * Note that while local->sw_scanning is true everything else but
 343          * nullfunc frames and probe requests will be dropped in
 344          * ieee80211_tx_h_check_assoc().
 345          */
 346         drv_sw_scan_start(local);
 347
 348         mutex_lock(&local->iflist_mtx);
 349         list_for_each_entry(sdata, &local->interfaces, list) {
 350                 if (!netif_running(sdata->dev))
 351                         continue;
 352
 353                 /* disable beaconing */
 354                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 355                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 356                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 357                         ieee80211_bss_info_change_notify(
 358                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 359
 360                 /*
 361                  * only handle non-STA interfaces here, STA interfaces
 362                  * are handled in the scan state machine
 363                  */
 364                 if (sdata->vif.type != NL80211_IFTYPE_STATION)
 365                         netif_stop_queue(sdata->dev);
 366         }
 367         mutex_unlock(&local->iflist_mtx);
 368
 369         local->next_scan_state = SCAN_DECISION;
 370         local->scan_channel_idx = 0;
 371
 372         ieee80211_configure_filter(local);
 373
 374         /* TODO: start scan as soon as all nullfunc frames are ACKed */
 375         ieee80211_queue_delayed_work(&local->hw,
 376                                      &local->scan_work,
 377                                      IEEE80211_CHANNEL_TIME);
 378
 379         return 0;
 380 }
 381
 382
 383 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 384                                   struct cfg80211_scan_request *req)
 385 {
 386         struct ieee80211_local *local = sdata->local;
 387         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 388         int rc;
 389
 390         if (local->scan_req)
 391                 return -EBUSY;
 392
 393         if (local->ops->hw_scan) {
 394                 u8 *ies;
 395                 int ielen;
 396
 397                 ies = kmalloc(2 + IEEE80211_MAX_SSID_LEN +
 398                               local->scan_ies_len + req->ie_len, GFP_KERNEL);
 399                 if (!ies)
 400                         return -ENOMEM;
 401
 402                 ielen = ieee80211_build_preq_ies(local, ies,
 403                                                  req->ie, req->ie_len);
 404                 local->orig_ies = req->ie;
 405                 local->orig_ies_len = req->ie_len;
 406                 req->ie = ies;
 407                 req->ie_len = ielen;
 408         }
 409
 410         local->scan_req = req;
 411         local->scan_sdata = sdata;
 412
 413         if (req != local->int_scan_req &&
 414             sdata->vif.type == NL80211_IFTYPE_STATION &&
 415             !list_empty(&ifmgd->work_list)) {
 416                 /* actually wait for the work it's doing to finish/time out */
 417                 set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
 418                 return 0;
 419         }
 420
 421         if (local->ops->hw_scan)
 422                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 423         else
 424                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 425         /*
 426          * Kicking off the scan need not be protected,
 427          * only the scan variable stuff, since now
 428          * local->scan_req is assigned and other callers
 429          * will abort their scan attempts.
 430          *
 431          * This avoids getting a scan_mtx -> iflist_mtx
 432          * dependency, so that the scan completed calls
 433          * have more locking freedom.
 434          */
 435
 436         ieee80211_recalc_idle(local);
 437         mutex_unlock(&local->scan_mtx);
 438
 439         if (local->ops->hw_scan)
 440                 rc = drv_hw_scan(local, local->scan_req);
 441         else
 442                 rc = ieee80211_start_sw_scan(local);
 443
 444         mutex_lock(&local->scan_mtx);
 445
 446         if (rc) {
 447                 if (local->ops->hw_scan)
 448                         ieee80211_restore_scan_ies(local);
 449                 local->scanning = 0;
 450
 451                 ieee80211_recalc_idle(local);
 452
 453                 local->scan_req = NULL;
 454                 local->scan_sdata = NULL;
 455         }
 456
 457         return rc;
 458 }
 459
 460 static int ieee80211_scan_state_decision(struct ieee80211_local *local,
 461                                          unsigned long *next_delay)
 462 {
 463         bool associated = false;
 464         struct ieee80211_sub_if_data *sdata;
 465
 466         /* if no more bands/channels left, complete scan and advance to the idle state */
 467         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 468                 ieee80211_scan_completed(&local->hw, false);
 469                 return 1;
 470         }
 471
 472         /* check if at least one STA interface is associated */
 473         mutex_lock(&local->iflist_mtx);
 474         list_for_each_entry(sdata, &local->interfaces, list) {
 475                 if (!netif_running(sdata->dev))
 476                         continue;
 477
 478                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 479                         if (sdata->u.mgd.associated) {
 480                                 associated = true;
 481                                 break;
 482                         }
 483                 }
 484         }
 485         mutex_unlock(&local->iflist_mtx);
 486
 487         if (local->scan_channel) {
 488                 /*
 489                  * we're currently scanning a different channel, let's
 490                  * switch back to the operating channel now if at least
 491                  * one interface is associated. Otherwise just scan the
 492                  * next channel
 493                  */
 494                 if (associated)
 495                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
 496                 else
 497                         local->next_scan_state = SCAN_SET_CHANNEL;
 498         } else {
 499                 /*
 500                  * we're on the operating channel currently, let's
 501                  * leave that channel now to scan another one
 502                  */
 503                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
 504         }
 505
 506         *next_delay = 0;
 507         return 0;
 508 }
 509
 510 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
 511                                                     unsigned long *next_delay)
 512 {
 513         struct ieee80211_sub_if_data *sdata;
 514
 515         /*
 516          * notify the AP about us leaving the channel and stop all STA interfaces
 517          */
 518         mutex_lock(&local->iflist_mtx);
 519         list_for_each_entry(sdata, &local->interfaces, list) {
 520                 if (!netif_running(sdata->dev))
 521                         continue;
 522
 523                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 524                         netif_stop_queue(sdata->dev);
 525                         if (sdata->u.mgd.associated)
 526                                 ieee80211_scan_ps_enable(sdata);
 527                 }
 528         }
 529         mutex_unlock(&local->iflist_mtx);
 530
 531         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
 532
 533         /* advance to the next channel to be scanned */
 534         *next_delay = HZ / 10;
 535         local->next_scan_state = SCAN_SET_CHANNEL;
 536 }
 537
 538 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
 539                                                     unsigned long *next_delay)
 540 {
 541         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 542
 543         /* switch back to the operating channel */
 544         local->scan_channel = NULL;
 545         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 546
 547         /*
 548          * notify the AP about us being back and restart all STA interfaces
 549          */
 550         mutex_lock(&local->iflist_mtx);
 551         list_for_each_entry(sdata, &local->interfaces, list) {
 552                 if (!netif_running(sdata->dev))
 553                         continue;
 554
 555                 /* Tell AP we're back */
 556                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 557                         if (sdata->u.mgd.associated)
 558                                 ieee80211_scan_ps_disable(sdata);
 559                         netif_wake_queue(sdata->dev);
 560                 }
 561         }
 562         mutex_unlock(&local->iflist_mtx);
 563
 564         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
 565
 566         *next_delay = HZ / 5;
 567         local->next_scan_state = SCAN_DECISION;
 568 }
 569
 570 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 571                                              unsigned long *next_delay)
 572 {
 573         int skip;
 574         struct ieee80211_channel *chan;
 575         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 576
 577         skip = 0;
 578         chan = local->scan_req->channels[local->scan_channel_idx];
 579
 580         if (chan->flags & IEEE80211_CHAN_DISABLED ||
 581             (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
 582              chan->flags & IEEE80211_CHAN_NO_IBSS))
 583                 skip = 1;
 584
 585         if (!skip) {
 586                 local->scan_channel = chan;
 587                 if (ieee80211_hw_config(local,
 588                                         IEEE80211_CONF_CHANGE_CHANNEL))
 589                         skip = 1;
 590         }
 591
 592         /* advance state machine to next channel/band */
 593         local->scan_channel_idx++;
 594
 595         if (skip) {
 596                 /* if we skip this channel return to the decision state */
 597                 local->next_scan_state = SCAN_DECISION;
 598                 return;
 599         }
 600
 601         /*
 602          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 603          * (which unfortunately doesn't say _why_ step a) is done,
 604          * but it waits for the probe delay or until a frame is
 605          * received - and the received frame would update the NAV).
 606          * For now, we do not support waiting until a frame is
 607          * received.
 608          *
 609          * In any case, it is not necessary for a passive scan.
 610          */
 611         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 612             !local->scan_req->n_ssids) {
 613                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 614                 local->next_scan_state = SCAN_DECISION;
 615                 return;
 616         }
 617
 618         /* active scan, send probes */
 619         *next_delay = IEEE80211_PROBE_DELAY;
 620         local->next_scan_state = SCAN_SEND_PROBE;
 621 }
 622
 623 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 624                                             unsigned long *next_delay)
 625 {
 626         int i;
 627         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 628
 629         for (i = 0; i < local->scan_req->n_ssids; i++)
 630                 ieee80211_send_probe_req(
 631                         sdata, NULL,
 632                         local->scan_req->ssids[i].ssid,
 633                         local->scan_req->ssids[i].ssid_len,
 634                         local->scan_req->ie, local->scan_req->ie_len);
 635
 636         /*
 637          * After sending probe requests, wait for probe responses
 638          * on the channel.
 639          */
 640         *next_delay = IEEE80211_CHANNEL_TIME;
 641         local->next_scan_state = SCAN_DECISION;
 642 }
 643
 644 void ieee80211_scan_work(struct work_struct *work)
 645 {
 646         struct ieee80211_local *local =
 647                 container_of(work, struct ieee80211_local, scan_work.work);
 648         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 649         unsigned long next_delay = 0;
 650
 651         mutex_lock(&local->scan_mtx);
 652         if (!sdata || !local->scan_req) {
 653                 mutex_unlock(&local->scan_mtx);
 654                 return;
 655         }
 656
 657         if (local->scan_req && !local->scanning) {
 658                 struct cfg80211_scan_request *req = local->scan_req;
 659                 int rc;
 660
 661                 local->scan_req = NULL;
 662                 local->scan_sdata = 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 abortscan;
 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         abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
 755                     (!local->scanning && local->scan_req);
 756         mutex_unlock(&local->scan_mtx);
 757
 758         if (abortscan)
 759                 ieee80211_scan_completed(&local->hw, true);
 760 }