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 AP/no TIM element */
  94         if (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         local->scan_sdata = NULL;
 284
 285         was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 286         local->scanning = 0;
 287         local->scan_channel = NULL;
 288
 289         /* we only have to protect scan_req and hw/sw scan */
 290         mutex_unlock(&local->scan_mtx);
 291
 292         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 293         if (was_hw_scan)
 294                 goto done;
 295
 296         ieee80211_configure_filter(local);
 297
 298         drv_sw_scan_complete(local);
 299
 300         mutex_lock(&local->iflist_mtx);
 301         list_for_each_entry(sdata, &local->interfaces, list) {
 302                 if (!netif_running(sdata->dev))
 303                         continue;
 304
 305                 /* Tell AP we're back */
 306                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 307                         if (sdata->u.mgd.associated) {
 308                                 ieee80211_scan_ps_disable(sdata);
 309                                 netif_tx_wake_all_queues(sdata->dev);
 310                         }
 311                 } else
 312                         netif_tx_wake_all_queues(sdata->dev);
 313
 314                 /* re-enable beaconing */
 315                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 316                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 317                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 318                         ieee80211_bss_info_change_notify(
 319                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 320         }
 321         mutex_unlock(&local->iflist_mtx);
 322
 323  done:
 324         ieee80211_recalc_idle(local);
 325         ieee80211_mlme_notify_scan_completed(local);
 326         ieee80211_ibss_notify_scan_completed(local);
 327         ieee80211_mesh_notify_scan_completed(local);
 328 }
 329 EXPORT_SYMBOL(ieee80211_scan_completed);
 330
 331 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 332 {
 333         struct ieee80211_sub_if_data *sdata;
 334
 335         /*
 336          * Hardware/driver doesn't support hw_scan, so use software
 337          * scanning instead. First send a nullfunc frame with power save
 338          * bit on so that AP will buffer the frames for us while we are not
 339          * listening, then send probe requests to each channel and wait for
 340          * the responses. After all channels are scanned, tune back to the
 341          * original channel and send a nullfunc frame with power save bit
 342          * off to trigger the AP to send us all the buffered frames.
 343          *
 344          * Note that while local->sw_scanning is true everything else but
 345          * nullfunc frames and probe requests will be dropped in
 346          * ieee80211_tx_h_check_assoc().
 347          */
 348         drv_sw_scan_start(local);
 349
 350         mutex_lock(&local->iflist_mtx);
 351         list_for_each_entry(sdata, &local->interfaces, list) {
 352                 if (!netif_running(sdata->dev))
 353                         continue;
 354
 355                 /* disable beaconing */
 356                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
 357                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
 358                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 359                         ieee80211_bss_info_change_notify(
 360                                 sdata, BSS_CHANGED_BEACON_ENABLED);
 361
 362                 /*
 363                  * only handle non-STA interfaces here, STA interfaces
 364                  * are handled in the scan state machine
 365                  */
 366                 if (sdata->vif.type != NL80211_IFTYPE_STATION)
 367                         netif_tx_stop_all_queues(sdata->dev);
 368         }
 369         mutex_unlock(&local->iflist_mtx);
 370
 371         local->next_scan_state = SCAN_DECISION;
 372         local->scan_channel_idx = 0;
 373
 374         ieee80211_configure_filter(local);
 375
 376         /* TODO: start scan as soon as all nullfunc frames are ACKed */
 377         ieee80211_queue_delayed_work(&local->hw,
 378                                      &local->scan_work,
 379                                      IEEE80211_CHANNEL_TIME);
 380
 381         return 0;
 382 }
 383
 384
 385 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 386                                   struct cfg80211_scan_request *req)
 387 {
 388         struct ieee80211_local *local = sdata->local;
 389         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 390         int rc;
 391
 392         if (local->scan_req)
 393                 return -EBUSY;
 394
 395         if (local->ops->hw_scan) {
 396                 u8 *ies;
 397                 int ielen;
 398
 399                 ies = kmalloc(2 + IEEE80211_MAX_SSID_LEN +
 400                               local->scan_ies_len + req->ie_len, GFP_KERNEL);
 401                 if (!ies)
 402                         return -ENOMEM;
 403
 404                 ielen = ieee80211_build_preq_ies(local, ies,
 405                                                  req->ie, req->ie_len);
 406                 local->orig_ies = req->ie;
 407                 local->orig_ies_len = req->ie_len;
 408                 req->ie = ies;
 409                 req->ie_len = ielen;
 410         }
 411
 412         local->scan_req = req;
 413         local->scan_sdata = sdata;
 414
 415         if (req != local->int_scan_req &&
 416             sdata->vif.type == NL80211_IFTYPE_STATION &&
 417             !list_empty(&ifmgd->work_list)) {
 418                 /* actually wait for the work it's doing to finish/time out */
 419                 set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
 420                 return 0;
 421         }
 422
 423         if (local->ops->hw_scan)
 424                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 425         else
 426                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 427         /*
 428          * Kicking off the scan need not be protected,
 429          * only the scan variable stuff, since now
 430          * local->scan_req is assigned and other callers
 431          * will abort their scan attempts.
 432          *
 433          * This avoids getting a scan_mtx -> iflist_mtx
 434          * dependency, so that the scan completed calls
 435          * have more locking freedom.
 436          */
 437
 438         ieee80211_recalc_idle(local);
 439         mutex_unlock(&local->scan_mtx);
 440
 441         if (local->ops->hw_scan)
 442                 rc = drv_hw_scan(local, local->scan_req);
 443         else
 444                 rc = ieee80211_start_sw_scan(local);
 445
 446         mutex_lock(&local->scan_mtx);
 447
 448         if (rc) {
 449                 if (local->ops->hw_scan)
 450                         ieee80211_restore_scan_ies(local);
 451                 local->scanning = 0;
 452
 453                 ieee80211_recalc_idle(local);
 454
 455                 local->scan_req = NULL;
 456                 local->scan_sdata = NULL;
 457         }
 458
 459         return rc;
 460 }
 461
 462 static int ieee80211_scan_state_decision(struct ieee80211_local *local,
 463                                          unsigned long *next_delay)
 464 {
 465         bool associated = false;
 466         struct ieee80211_sub_if_data *sdata;
 467
 468         /* if no more bands/channels left, complete scan and advance to the idle state */
 469         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 470                 ieee80211_scan_completed(&local->hw, false);
 471                 return 1;
 472         }
 473
 474         /* check if at least one STA interface is associated */
 475         mutex_lock(&local->iflist_mtx);
 476         list_for_each_entry(sdata, &local->interfaces, list) {
 477                 if (!netif_running(sdata->dev))
 478                         continue;
 479
 480                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 481                         if (sdata->u.mgd.associated) {
 482                                 associated = true;
 483                                 break;
 484                         }
 485                 }
 486         }
 487         mutex_unlock(&local->iflist_mtx);
 488
 489         if (local->scan_channel) {
 490                 /*
 491                  * we're currently scanning a different channel, let's
 492                  * switch back to the operating channel now if at least
 493                  * one interface is associated. Otherwise just scan the
 494                  * next channel
 495                  */
 496                 if (associated)
 497                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
 498                 else
 499                         local->next_scan_state = SCAN_SET_CHANNEL;
 500         } else {
 501                 /*
 502                  * we're on the operating channel currently, let's
 503                  * leave that channel now to scan another one
 504                  */
 505                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
 506         }
 507
 508         *next_delay = 0;
 509         return 0;
 510 }
 511
 512 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
 513                                                     unsigned long *next_delay)
 514 {
 515         struct ieee80211_sub_if_data *sdata;
 516
 517         /*
 518          * notify the AP about us leaving the channel and stop all STA interfaces
 519          */
 520         mutex_lock(&local->iflist_mtx);
 521         list_for_each_entry(sdata, &local->interfaces, list) {
 522                 if (!netif_running(sdata->dev))
 523                         continue;
 524
 525                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 526                         netif_tx_stop_all_queues(sdata->dev);
 527                         if (sdata->u.mgd.associated)
 528                                 ieee80211_scan_ps_enable(sdata);
 529                 }
 530         }
 531         mutex_unlock(&local->iflist_mtx);
 532
 533         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
 534
 535         /* advance to the next channel to be scanned */
 536         *next_delay = HZ / 10;
 537         local->next_scan_state = SCAN_SET_CHANNEL;
 538 }
 539
 540 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
 541                                                     unsigned long *next_delay)
 542 {
 543         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 544
 545         /* switch back to the operating channel */
 546         local->scan_channel = NULL;
 547         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 548
 549         /*
 550          * notify the AP about us being back and restart all STA interfaces
 551          */
 552         mutex_lock(&local->iflist_mtx);
 553         list_for_each_entry(sdata, &local->interfaces, list) {
 554                 if (!netif_running(sdata->dev))
 555                         continue;
 556
 557                 /* Tell AP we're back */
 558                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 559                         if (sdata->u.mgd.associated)
 560                                 ieee80211_scan_ps_disable(sdata);
 561                         netif_tx_wake_all_queues(sdata->dev);
 562                 }
 563         }
 564         mutex_unlock(&local->iflist_mtx);
 565
 566         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
 567
 568         *next_delay = HZ / 5;
 569         local->next_scan_state = SCAN_DECISION;
 570 }
 571
 572 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 573                                              unsigned long *next_delay)
 574 {
 575         int skip;
 576         struct ieee80211_channel *chan;
 577         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 578
 579         skip = 0;
 580         chan = local->scan_req->channels[local->scan_channel_idx];
 581
 582         if (chan->flags & IEEE80211_CHAN_DISABLED ||
 583             (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
 584              chan->flags & IEEE80211_CHAN_NO_IBSS))
 585                 skip = 1;
 586
 587         if (!skip) {
 588                 local->scan_channel = chan;
 589                 if (ieee80211_hw_config(local,
 590                                         IEEE80211_CONF_CHANGE_CHANNEL))
 591                         skip = 1;
 592         }
 593
 594         /* advance state machine to next channel/band */
 595         local->scan_channel_idx++;
 596
 597         if (skip) {
 598                 /* if we skip this channel return to the decision state */
 599                 local->next_scan_state = SCAN_DECISION;
 600                 return;
 601         }
 602
 603         /*
 604          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 605          * (which unfortunately doesn't say _why_ step a) is done,
 606          * but it waits for the probe delay or until a frame is
 607          * received - and the received frame would update the NAV).
 608          * For now, we do not support waiting until a frame is
 609          * received.
 610          *
 611          * In any case, it is not necessary for a passive scan.
 612          */
 613         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 614             !local->scan_req->n_ssids) {
 615                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 616                 local->next_scan_state = SCAN_DECISION;
 617                 return;
 618         }
 619
 620         /* active scan, send probes */
 621         *next_delay = IEEE80211_PROBE_DELAY;
 622         local->next_scan_state = SCAN_SEND_PROBE;
 623 }
 624
 625 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 626                                             unsigned long *next_delay)
 627 {
 628         int i;
 629         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 630
 631         for (i = 0; i < local->scan_req->n_ssids; i++)
 632                 ieee80211_send_probe_req(
 633                         sdata, NULL,
 634                         local->scan_req->ssids[i].ssid,
 635                         local->scan_req->ssids[i].ssid_len,
 636                         local->scan_req->ie, local->scan_req->ie_len);
 637
 638         /*
 639          * After sending probe requests, wait for probe responses
 640          * on the channel.
 641          */
 642         *next_delay = IEEE80211_CHANNEL_TIME;
 643         local->next_scan_state = SCAN_DECISION;
 644 }
 645
 646 void ieee80211_scan_work(struct work_struct *work)
 647 {
 648         struct ieee80211_local *local =
 649                 container_of(work, struct ieee80211_local, scan_work.work);
 650         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 651         unsigned long next_delay = 0;
 652
 653         mutex_lock(&local->scan_mtx);
 654         if (!sdata || !local->scan_req) {
 655                 mutex_unlock(&local->scan_mtx);
 656                 return;
 657         }
 658
 659         if (local->scan_req && !local->scanning) {
 660                 struct cfg80211_scan_request *req = local->scan_req;
 661                 int rc;
 662
 663                 local->scan_req = NULL;
 664                 local->scan_sdata = NULL;
 665
 666                 rc = __ieee80211_start_scan(sdata, req);
 667                 mutex_unlock(&local->scan_mtx);
 668
 669                 if (rc)
 670                         ieee80211_scan_completed(&local->hw, true);
 671                 return;
 672         }
 673
 674         mutex_unlock(&local->scan_mtx);
 675
 676         /*
 677          * Avoid re-scheduling when the sdata is going away.
 678          */
 679         if (!netif_running(sdata->dev)) {
 680                 ieee80211_scan_completed(&local->hw, true);
 681                 return;
 682         }
 683
 684         /*
 685          * as long as no delay is required advance immediately
 686          * without scheduling a new work
 687          */
 688         do {
 689                 switch (local->next_scan_state) {
 690                 case SCAN_DECISION:
 691                         if (ieee80211_scan_state_decision(local, &next_delay))
 692                                 return;
 693                         break;
 694                 case SCAN_SET_CHANNEL:
 695                         ieee80211_scan_state_set_channel(local, &next_delay);
 696                         break;
 697                 case SCAN_SEND_PROBE:
 698                         ieee80211_scan_state_send_probe(local, &next_delay);
 699                         break;
 700                 case SCAN_LEAVE_OPER_CHANNEL:
 701                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
 702                         break;
 703                 case SCAN_ENTER_OPER_CHANNEL:
 704                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 705                         break;
 706                 }
 707         } while (next_delay == 0);
 708
 709         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 710 }
 711
 712 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 713                            struct cfg80211_scan_request *req)
 714 {
 715         int res;
 716
 717         mutex_lock(&sdata->local->scan_mtx);
 718         res = __ieee80211_start_scan(sdata, req);
 719         mutex_unlock(&sdata->local->scan_mtx);
 720
 721         return res;
 722 }
 723
 724 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 725                                     const u8 *ssid, u8 ssid_len)
 726 {
 727         struct ieee80211_local *local = sdata->local;
 728         int ret = -EBUSY;
 729
 730         mutex_lock(&local->scan_mtx);
 731
 732         /* busy scanning */
 733         if (local->scan_req)
 734                 goto unlock;
 735
 736         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 737         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 738
 739         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 740  unlock:
 741         mutex_unlock(&local->scan_mtx);
 742         return ret;
 743 }
 744
 745 void ieee80211_scan_cancel(struct ieee80211_local *local)
 746 {
 747         bool abortscan;
 748
 749         cancel_delayed_work_sync(&local->scan_work);
 750
 751         /*
 752          * Only call this function when a scan can't be
 753          * queued -- mostly at suspend under RTNL.
 754          */
 755         mutex_lock(&local->scan_mtx);
 756         abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
 757                     (!local->scanning && local->scan_req);
 758         mutex_unlock(&local->scan_mtx);
 759
 760         if (abortscan)
 761                 ieee80211_scan_completed(&local->hw, true);
 762 }