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/if_arp.h>
  16 #include <linux/rtnetlink.h>
  17 #include <net/mac80211.h>
  18
  19 #include "ieee80211_i.h"
  20 #include "driver-ops.h"
  21 #include "mesh.h"
  22
  23 #define IEEE80211_PROBE_DELAY (HZ / 33)
  24 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  25 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
  26
  27 struct ieee80211_bss *
  28 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
  29                      u8 *ssid, u8 ssid_len)
  30 {
  31         struct cfg80211_bss *cbss;
  32
  33         cbss = cfg80211_get_bss(local->hw.wiphy,
  34                                 ieee80211_get_channel(local->hw.wiphy, freq),
  35                                 bssid, ssid, ssid_len, 0, 0);
  36         if (!cbss)
  37                 return NULL;
  38         return (void *)cbss->priv;
  39 }
  40
  41 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
  42 {
  43         struct ieee80211_bss *bss = (void *)cbss->priv;
  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         if (!bss)
  53                 return;
  54         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
  55 }
  56
  57 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  58 {
  59         u8 qos_info;
  60
  61         if (elems->wmm_info && elems->wmm_info_len == 7
  62             && elems->wmm_info[5] == 1)
  63                 qos_info = elems->wmm_info[6];
  64         else if (elems->wmm_param && elems->wmm_param_len == 24
  65                  && elems->wmm_param[5] == 1)
  66                 qos_info = elems->wmm_param[6];
  67         else
  68                 /* no valid wmm information or parameter element found */
  69                 return false;
  70
  71         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  72 }
  73
  74 struct ieee80211_bss *
  75 ieee80211_bss_info_update(struct ieee80211_local *local,
  76                           struct ieee80211_rx_status *rx_status,
  77                           struct ieee80211_mgmt *mgmt,
  78                           size_t len,
  79                           struct ieee802_11_elems *elems,
  80                           struct ieee80211_channel *channel,
  81                           bool beacon)
  82 {
  83         struct cfg80211_bss *cbss;
  84         struct ieee80211_bss *bss;
  85         int clen;
  86         s32 signal = 0;
  87
  88         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  89                 signal = rx_status->signal * 100;
  90         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  91                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  92
  93         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  94                                          mgmt, len, signal, GFP_ATOMIC);
  95
  96         if (!cbss)
  97                 return NULL;
  98
  99         cbss->free_priv = ieee80211_rx_bss_free;
 100         bss = (void *)cbss->priv;
 101
 102         /* save the ERP value so that it is available at association time */
 103         if (elems->erp_info && elems->erp_info_len >= 1) {
 104                 bss->erp_value = elems->erp_info[0];
 105                 bss->has_erp_value = 1;
 106         }
 107
 108         if (elems->tim) {
 109                 struct ieee80211_tim_ie *tim_ie =
 110                         (struct ieee80211_tim_ie *)elems->tim;
 111                 bss->dtim_period = tim_ie->dtim_period;
 112         }
 113
 114         bss->supp_rates_len = 0;
 115         if (elems->supp_rates) {
 116                 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
 117                 if (clen > elems->supp_rates_len)
 118                         clen = elems->supp_rates_len;
 119                 memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates,
 120                        clen);
 121                 bss->supp_rates_len += clen;
 122         }
 123         if (elems->ext_supp_rates) {
 124                 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
 125                 if (clen > elems->ext_supp_rates_len)
 126                         clen = elems->ext_supp_rates_len;
 127                 memcpy(&bss->supp_rates[bss->supp_rates_len],
 128                        elems->ext_supp_rates, clen);
 129                 bss->supp_rates_len += clen;
 130         }
 131
 132         bss->wmm_used = elems->wmm_param || elems->wmm_info;
 133         bss->uapsd_supported = is_uapsd_supported(elems);
 134
 135         if (!beacon)
 136                 bss->last_probe_resp = jiffies;
 137
 138         return bss;
 139 }
 140
 141 ieee80211_rx_result
 142 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 143 {
 144         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 145         struct ieee80211_mgmt *mgmt;
 146         struct ieee80211_bss *bss;
 147         u8 *elements;
 148         struct ieee80211_channel *channel;
 149         size_t baselen;
 150         int freq;
 151         __le16 fc;
 152         bool presp, beacon = false;
 153         struct ieee802_11_elems elems;
 154
 155         if (skb->len < 2)
 156                 return RX_DROP_UNUSABLE;
 157
 158         mgmt = (struct ieee80211_mgmt *) skb->data;
 159         fc = mgmt->frame_control;
 160
 161         if (ieee80211_is_ctl(fc))
 162                 return RX_CONTINUE;
 163
 164         if (skb->len < 24)
 165                 return RX_DROP_MONITOR;
 166
 167         presp = ieee80211_is_probe_resp(fc);
 168         if (presp) {
 169                 /* ignore ProbeResp to foreign address */
 170                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
 171                         return RX_DROP_MONITOR;
 172
 173                 presp = true;
 174                 elements = mgmt->u.probe_resp.variable;
 175                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 176         } else {
 177                 beacon = ieee80211_is_beacon(fc);
 178                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 179                 elements = mgmt->u.beacon.variable;
 180         }
 181
 182         if (!presp && !beacon)
 183                 return RX_CONTINUE;
 184
 185         if (baselen > skb->len)
 186                 return RX_DROP_MONITOR;
 187
 188         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 189
 190         if (elems.ds_params && elems.ds_params_len == 1)
 191                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
 192         else
 193                 freq = rx_status->freq;
 194
 195         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 196
 197         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 198                 return RX_DROP_MONITOR;
 199
 200         bss = ieee80211_bss_info_update(sdata->local, rx_status,
 201                                         mgmt, skb->len, &elems,
 202                                         channel, beacon);
 203         if (bss)
 204                 ieee80211_rx_bss_put(sdata->local, bss);
 205
 206         dev_kfree_skb(skb);
 207         return RX_QUEUED;
 208 }
 209
 210 /* return false if no more work */
 211 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 212 {
 213         struct cfg80211_scan_request *req = local->scan_req;
 214         enum ieee80211_band band;
 215         int i, ielen, n_chans;
 216
 217         do {
 218                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 219                         return false;
 220
 221                 band = local->hw_scan_band;
 222                 n_chans = 0;
 223                 for (i = 0; i < req->n_channels; i++) {
 224                         if (req->channels[i]->band == band) {
 225                                 local->hw_scan_req->channels[n_chans] =
 226                                                         req->channels[i];
 227                                 n_chans++;
 228                         }
 229                 }
 230
 231                 local->hw_scan_band++;
 232         } while (!n_chans);
 233
 234         local->hw_scan_req->n_channels = n_chans;
 235
 236         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 237                                          req->ie, req->ie_len, band);
 238         local->hw_scan_req->ie_len = ielen;
 239
 240         return true;
 241 }
 242
 243 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 244 {
 245         struct ieee80211_local *local = hw_to_local(hw);
 246         bool was_hw_scan;
 247
 248         mutex_lock(&local->scan_mtx);
 249
 250         /*
 251          * It's ok to abort a not-yet-running scan (that
 252          * we have one at all will be verified by checking
 253          * local->scan_req next), but not to complete it
 254          * successfully.
 255          */
 256         if (WARN_ON(!local->scanning && !aborted))
 257                 aborted = true;
 258
 259         if (WARN_ON(!local->scan_req)) {
 260                 mutex_unlock(&local->scan_mtx);
 261                 return;
 262         }
 263
 264         was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 265         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 266                 ieee80211_queue_delayed_work(&local->hw,
 267                                              &local->scan_work, 0);
 268                 mutex_unlock(&local->scan_mtx);
 269                 return;
 270         }
 271
 272         kfree(local->hw_scan_req);
 273         local->hw_scan_req = NULL;
 274
 275         if (local->scan_req != local->int_scan_req)
 276                 cfg80211_scan_done(local->scan_req, aborted);
 277         local->scan_req = NULL;
 278         local->scan_sdata = NULL;
 279
 280         local->scanning = 0;
 281         local->scan_channel = NULL;
 282
 283         /* we only have to protect scan_req and hw/sw scan */
 284         mutex_unlock(&local->scan_mtx);
 285
 286         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 287         if (was_hw_scan)
 288                 goto done;
 289
 290         ieee80211_configure_filter(local);
 291
 292         drv_sw_scan_complete(local);
 293
 294         ieee80211_offchannel_return(local, true);
 295
 296  done:
 297         ieee80211_recalc_idle(local);
 298         ieee80211_mlme_notify_scan_completed(local);
 299         ieee80211_ibss_notify_scan_completed(local);
 300         ieee80211_mesh_notify_scan_completed(local);
 301         ieee80211_queue_work(&local->hw, &local->work_work);
 302 }
 303 EXPORT_SYMBOL(ieee80211_scan_completed);
 304
 305 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 306 {
 307         /*
 308          * Hardware/driver doesn't support hw_scan, so use software
 309          * scanning instead. First send a nullfunc frame with power save
 310          * bit on so that AP will buffer the frames for us while we are not
 311          * listening, then send probe requests to each channel and wait for
 312          * the responses. After all channels are scanned, tune back to the
 313          * original channel and send a nullfunc frame with power save bit
 314          * off to trigger the AP to send us all the buffered frames.
 315          *
 316          * Note that while local->sw_scanning is true everything else but
 317          * nullfunc frames and probe requests will be dropped in
 318          * ieee80211_tx_h_check_assoc().
 319          */
 320         drv_sw_scan_start(local);
 321
 322         ieee80211_offchannel_stop_beaconing(local);
 323
 324         local->next_scan_state = SCAN_DECISION;
 325         local->scan_channel_idx = 0;
 326
 327         drv_flush(local, false);
 328
 329         ieee80211_configure_filter(local);
 330
 331         ieee80211_queue_delayed_work(&local->hw,
 332                                      &local->scan_work,
 333                                      IEEE80211_CHANNEL_TIME);
 334
 335         return 0;
 336 }
 337
 338
 339 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 340                                   struct cfg80211_scan_request *req)
 341 {
 342         struct ieee80211_local *local = sdata->local;
 343         int rc;
 344
 345         if (local->scan_req)
 346                 return -EBUSY;
 347
 348         if (!list_empty(&local->work_list)) {
 349                 /* wait for the work to finish/time out */
 350                 local->scan_req = req;
 351                 local->scan_sdata = sdata;
 352                 return 0;
 353         }
 354
 355         if (local->ops->hw_scan) {
 356                 u8 *ies;
 357
 358                 local->hw_scan_req = kmalloc(
 359                                 sizeof(*local->hw_scan_req) +
 360                                 req->n_channels * sizeof(req->channels[0]) +
 361                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 362                                 req->ie_len, GFP_KERNEL);
 363                 if (!local->hw_scan_req)
 364                         return -ENOMEM;
 365
 366                 local->hw_scan_req->ssids = req->ssids;
 367                 local->hw_scan_req->n_ssids = req->n_ssids;
 368                 ies = (u8 *)local->hw_scan_req +
 369                         sizeof(*local->hw_scan_req) +
 370                         req->n_channels * sizeof(req->channels[0]);
 371                 local->hw_scan_req->ie = ies;
 372
 373                 local->hw_scan_band = 0;
 374
 375                 /*
 376                  * After allocating local->hw_scan_req, we must
 377                  * go through until ieee80211_prep_hw_scan(), so
 378                  * anything that might be changed here and leave
 379                  * this function early must not go after this
 380                  * allocation.
 381                  */
 382         }
 383
 384         local->scan_req = req;
 385         local->scan_sdata = sdata;
 386
 387         if (local->ops->hw_scan)
 388                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 389         else
 390                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 391
 392         /*
 393          * Kicking off the scan need not be protected,
 394          * only the scan variable stuff, since now
 395          * local->scan_req is assigned and other callers
 396          * will abort their scan attempts.
 397          *
 398          * This avoids too many locking dependencies
 399          * so that the scan completed calls have more
 400          * locking freedom.
 401          */
 402
 403         ieee80211_recalc_idle(local);
 404         mutex_unlock(&local->scan_mtx);
 405
 406         if (local->ops->hw_scan) {
 407                 WARN_ON(!ieee80211_prep_hw_scan(local));
 408                 rc = drv_hw_scan(local, local->hw_scan_req);
 409         } else
 410                 rc = ieee80211_start_sw_scan(local);
 411
 412         mutex_lock(&local->scan_mtx);
 413
 414         if (rc) {
 415                 kfree(local->hw_scan_req);
 416                 local->hw_scan_req = NULL;
 417                 local->scanning = 0;
 418
 419                 ieee80211_recalc_idle(local);
 420
 421                 local->scan_req = NULL;
 422                 local->scan_sdata = NULL;
 423         }
 424
 425         return rc;
 426 }
 427
 428 static int ieee80211_scan_state_decision(struct ieee80211_local *local,
 429                                          unsigned long *next_delay)
 430 {
 431         bool associated = false;
 432         struct ieee80211_sub_if_data *sdata;
 433
 434         /* if no more bands/channels left, complete scan and advance to the idle state */
 435         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 436                 ieee80211_scan_completed(&local->hw, false);
 437                 return 1;
 438         }
 439
 440         /* check if at least one STA interface is associated */
 441         mutex_lock(&local->iflist_mtx);
 442         list_for_each_entry(sdata, &local->interfaces, list) {
 443                 if (!ieee80211_sdata_running(sdata))
 444                         continue;
 445
 446                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 447                         if (sdata->u.mgd.associated) {
 448                                 associated = true;
 449                                 break;
 450                         }
 451                 }
 452         }
 453         mutex_unlock(&local->iflist_mtx);
 454
 455         if (local->scan_channel) {
 456                 /*
 457                  * we're currently scanning a different channel, let's
 458                  * switch back to the operating channel now if at least
 459                  * one interface is associated. Otherwise just scan the
 460                  * next channel
 461                  */
 462                 if (associated)
 463                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
 464                 else
 465                         local->next_scan_state = SCAN_SET_CHANNEL;
 466         } else {
 467                 /*
 468                  * we're on the operating channel currently, let's
 469                  * leave that channel now to scan another one
 470                  */
 471                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
 472         }
 473
 474         *next_delay = 0;
 475         return 0;
 476 }
 477
 478 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
 479                                                     unsigned long *next_delay)
 480 {
 481         ieee80211_offchannel_stop_station(local);
 482
 483         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
 484
 485         /*
 486          * What if the nullfunc frames didn't arrive?
 487          */
 488         drv_flush(local, false);
 489         if (local->ops->flush)
 490                 *next_delay = 0;
 491         else
 492                 *next_delay = HZ / 10;
 493
 494         /* advance to the next channel to be scanned */
 495         local->next_scan_state = SCAN_SET_CHANNEL;
 496 }
 497
 498 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
 499                                                     unsigned long *next_delay)
 500 {
 501         /* switch back to the operating channel */
 502         local->scan_channel = NULL;
 503         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 504
 505         /*
 506          * Only re-enable station mode interface now; beaconing will be
 507          * re-enabled once the full scan has been completed.
 508          */
 509         ieee80211_offchannel_return(local, false);
 510
 511         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
 512
 513         *next_delay = HZ / 5;
 514         local->next_scan_state = SCAN_DECISION;
 515 }
 516
 517 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 518                                              unsigned long *next_delay)
 519 {
 520         int skip;
 521         struct ieee80211_channel *chan;
 522
 523         skip = 0;
 524         chan = local->scan_req->channels[local->scan_channel_idx];
 525
 526         local->scan_channel = chan;
 527         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 528                 skip = 1;
 529
 530         /* advance state machine to next channel/band */
 531         local->scan_channel_idx++;
 532
 533         if (skip) {
 534                 /* if we skip this channel return to the decision state */
 535                 local->next_scan_state = SCAN_DECISION;
 536                 return;
 537         }
 538
 539         /*
 540          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 541          * (which unfortunately doesn't say _why_ step a) is done,
 542          * but it waits for the probe delay or until a frame is
 543          * received - and the received frame would update the NAV).
 544          * For now, we do not support waiting until a frame is
 545          * received.
 546          *
 547          * In any case, it is not necessary for a passive scan.
 548          */
 549         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 550             !local->scan_req->n_ssids) {
 551                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 552                 local->next_scan_state = SCAN_DECISION;
 553                 return;
 554         }
 555
 556         /* active scan, send probes */
 557         *next_delay = IEEE80211_PROBE_DELAY;
 558         local->next_scan_state = SCAN_SEND_PROBE;
 559 }
 560
 561 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 562                                             unsigned long *next_delay)
 563 {
 564         int i;
 565         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 566
 567         for (i = 0; i < local->scan_req->n_ssids; i++)
 568                 ieee80211_send_probe_req(
 569                         sdata, NULL,
 570                         local->scan_req->ssids[i].ssid,
 571                         local->scan_req->ssids[i].ssid_len,
 572                         local->scan_req->ie, local->scan_req->ie_len);
 573
 574         /*
 575          * After sending probe requests, wait for probe responses
 576          * on the channel.
 577          */
 578         *next_delay = IEEE80211_CHANNEL_TIME;
 579         local->next_scan_state = SCAN_DECISION;
 580 }
 581
 582 void ieee80211_scan_work(struct work_struct *work)
 583 {
 584         struct ieee80211_local *local =
 585                 container_of(work, struct ieee80211_local, scan_work.work);
 586         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 587         unsigned long next_delay = 0;
 588
 589         mutex_lock(&local->scan_mtx);
 590         if (!sdata || !local->scan_req) {
 591                 mutex_unlock(&local->scan_mtx);
 592                 return;
 593         }
 594
 595         if (local->hw_scan_req) {
 596                 int rc = drv_hw_scan(local, local->hw_scan_req);
 597                 mutex_unlock(&local->scan_mtx);
 598                 if (rc)
 599                         ieee80211_scan_completed(&local->hw, true);
 600                 return;
 601         }
 602
 603         if (local->scan_req && !local->scanning) {
 604                 struct cfg80211_scan_request *req = local->scan_req;
 605                 int rc;
 606
 607                 local->scan_req = NULL;
 608                 local->scan_sdata = NULL;
 609
 610                 rc = __ieee80211_start_scan(sdata, req);
 611                 mutex_unlock(&local->scan_mtx);
 612
 613                 if (rc)
 614                         ieee80211_scan_completed(&local->hw, true);
 615                 return;
 616         }
 617
 618         mutex_unlock(&local->scan_mtx);
 619
 620         /*
 621          * Avoid re-scheduling when the sdata is going away.
 622          */
 623         if (!ieee80211_sdata_running(sdata)) {
 624                 ieee80211_scan_completed(&local->hw, true);
 625                 return;
 626         }
 627
 628         /*
 629          * as long as no delay is required advance immediately
 630          * without scheduling a new work
 631          */
 632         do {
 633                 switch (local->next_scan_state) {
 634                 case SCAN_DECISION:
 635                         if (ieee80211_scan_state_decision(local, &next_delay))
 636                                 return;
 637                         break;
 638                 case SCAN_SET_CHANNEL:
 639                         ieee80211_scan_state_set_channel(local, &next_delay);
 640                         break;
 641                 case SCAN_SEND_PROBE:
 642                         ieee80211_scan_state_send_probe(local, &next_delay);
 643                         break;
 644                 case SCAN_LEAVE_OPER_CHANNEL:
 645                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
 646                         break;
 647                 case SCAN_ENTER_OPER_CHANNEL:
 648                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 649                         break;
 650                 }
 651         } while (next_delay == 0);
 652
 653         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 654 }
 655
 656 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 657                            struct cfg80211_scan_request *req)
 658 {
 659         int res;
 660
 661         mutex_lock(&sdata->local->scan_mtx);
 662         res = __ieee80211_start_scan(sdata, req);
 663         mutex_unlock(&sdata->local->scan_mtx);
 664
 665         return res;
 666 }
 667
 668 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 669                                     const u8 *ssid, u8 ssid_len)
 670 {
 671         struct ieee80211_local *local = sdata->local;
 672         int ret = -EBUSY;
 673
 674         mutex_lock(&local->scan_mtx);
 675
 676         /* busy scanning */
 677         if (local->scan_req)
 678                 goto unlock;
 679
 680         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 681         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 682
 683         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 684  unlock:
 685         mutex_unlock(&local->scan_mtx);
 686         return ret;
 687 }
 688
 689 void ieee80211_scan_cancel(struct ieee80211_local *local)
 690 {
 691         bool abortscan;
 692
 693         cancel_delayed_work_sync(&local->scan_work);
 694
 695         /*
 696          * Only call this function when a scan can't be
 697          * queued -- mostly at suspend under RTNL.
 698          */
 699         mutex_lock(&local->scan_mtx);
 700         abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
 701                     (!local->scanning && local->scan_req);
 702         mutex_unlock(&local->scan_mtx);
 703
 704         if (abortscan)
 705                 ieee80211_scan_completed(&local->hw, true);
 706 }