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/etherdevice.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/pm_qos.h>
  19 #include <net/sch_generic.h>
  20 #include <linux/slab.h>
  21 #include <linux/export.h>
  22 #include <net/mac80211.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "mesh.h"
  27
  28 #define IEEE80211_PROBE_DELAY (HZ / 33)
  29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
  31
  32 struct ieee80211_bss *
  33 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
  34                      u8 *ssid, u8 ssid_len)
  35 {
  36         struct cfg80211_bss *cbss;
  37
  38         cbss = cfg80211_get_bss(local->hw.wiphy,
  39                                 ieee80211_get_channel(local->hw.wiphy, freq),
  40                                 bssid, ssid, ssid_len, 0, 0);
  41         if (!cbss)
  42                 return NULL;
  43         return (void *)cbss->priv;
  44 }
  45
  46 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
  47 {
  48         struct ieee80211_bss *bss = (void *)cbss->priv;
  49
  50         kfree(bss_mesh_id(bss));
  51         kfree(bss_mesh_cfg(bss));
  52 }
  53
  54 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  55                           struct ieee80211_bss *bss)
  56 {
  57         if (!bss)
  58                 return;
  59         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
  60 }
  61
  62 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  63 {
  64         u8 qos_info;
  65
  66         if (elems->wmm_info && elems->wmm_info_len == 7
  67             && elems->wmm_info[5] == 1)
  68                 qos_info = elems->wmm_info[6];
  69         else if (elems->wmm_param && elems->wmm_param_len == 24
  70                  && elems->wmm_param[5] == 1)
  71                 qos_info = elems->wmm_param[6];
  72         else
  73                 /* no valid wmm information or parameter element found */
  74                 return false;
  75
  76         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  77 }
  78
  79 struct ieee80211_bss *
  80 ieee80211_bss_info_update(struct ieee80211_local *local,
  81                           struct ieee80211_rx_status *rx_status,
  82                           struct ieee80211_mgmt *mgmt,
  83                           size_t len,
  84                           struct ieee802_11_elems *elems,
  85                           struct ieee80211_channel *channel,
  86                           bool beacon)
  87 {
  88         struct cfg80211_bss *cbss;
  89         struct ieee80211_bss *bss;
  90         int clen, srlen;
  91         s32 signal = 0;
  92
  93         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  94                 signal = rx_status->signal * 100;
  95         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  96                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  97
  98         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  99                                          mgmt, len, signal, GFP_ATOMIC);
 100
 101         if (!cbss)
 102                 return NULL;
 103
 104         cbss->free_priv = ieee80211_rx_bss_free;
 105         bss = (void *)cbss->priv;
 106
 107         if (elems->parse_error) {
 108                 if (beacon)
 109                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
 110                 else
 111                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 112         } else {
 113                 if (beacon)
 114                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 115                 else
 116                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 117         }
 118
 119         /* save the ERP value so that it is available at association time */
 120         if (elems->erp_info && elems->erp_info_len >= 1 &&
 121                         (!elems->parse_error ||
 122                          !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 123                 bss->erp_value = elems->erp_info[0];
 124                 bss->has_erp_value = true;
 125                 if (!elems->parse_error)
 126                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 127         }
 128
 129         if (elems->tim && (!elems->parse_error ||
 130                            !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) {
 131                 struct ieee80211_tim_ie *tim_ie =
 132                         (struct ieee80211_tim_ie *)elems->tim;
 133                 bss->dtim_period = tim_ie->dtim_period;
 134                 if (!elems->parse_error)
 135                                 bss->valid_data |= IEEE80211_BSS_VALID_DTIM;
 136         }
 137
 138         /* If the beacon had no TIM IE, or it was invalid, use 1 */
 139         if (beacon && !bss->dtim_period)
 140                 bss->dtim_period = 1;
 141
 142         /* replace old supported rates if we get new values */
 143         if (!elems->parse_error ||
 144             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 145                 srlen = 0;
 146                 if (elems->supp_rates) {
 147                         clen = IEEE80211_MAX_SUPP_RATES;
 148                         if (clen > elems->supp_rates_len)
 149                                 clen = elems->supp_rates_len;
 150                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 151                         srlen += clen;
 152                 }
 153                 if (elems->ext_supp_rates) {
 154                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 155                         if (clen > elems->ext_supp_rates_len)
 156                                 clen = elems->ext_supp_rates_len;
 157                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 158                                clen);
 159                         srlen += clen;
 160                 }
 161                 if (srlen) {
 162                         bss->supp_rates_len = srlen;
 163                         if (!elems->parse_error)
 164                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 165                 }
 166         }
 167
 168         if (!elems->parse_error ||
 169             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 170                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 171                 bss->uapsd_supported = is_uapsd_supported(elems);
 172                 if (!elems->parse_error)
 173                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 174         }
 175
 176         if (!beacon)
 177                 bss->last_probe_resp = jiffies;
 178
 179         return bss;
 180 }
 181
 182 ieee80211_rx_result
 183 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 184 {
 185         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 186         struct ieee80211_mgmt *mgmt;
 187         struct ieee80211_bss *bss;
 188         u8 *elements;
 189         struct ieee80211_channel *channel;
 190         size_t baselen;
 191         int freq;
 192         __le16 fc;
 193         bool presp, beacon = false;
 194         struct ieee802_11_elems elems;
 195
 196         if (skb->len < 2)
 197                 return RX_DROP_UNUSABLE;
 198
 199         mgmt = (struct ieee80211_mgmt *) skb->data;
 200         fc = mgmt->frame_control;
 201
 202         if (ieee80211_is_ctl(fc))
 203                 return RX_CONTINUE;
 204
 205         if (skb->len < 24)
 206                 return RX_CONTINUE;
 207
 208         presp = ieee80211_is_probe_resp(fc);
 209         if (presp) {
 210                 /* ignore ProbeResp to foreign address */
 211                 if (compare_ether_addr(mgmt->da, sdata->vif.addr))
 212                         return RX_DROP_MONITOR;
 213
 214                 presp = true;
 215                 elements = mgmt->u.probe_resp.variable;
 216                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 217         } else {
 218                 beacon = ieee80211_is_beacon(fc);
 219                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 220                 elements = mgmt->u.beacon.variable;
 221         }
 222
 223         if (!presp && !beacon)
 224                 return RX_CONTINUE;
 225
 226         if (baselen > skb->len)
 227                 return RX_DROP_MONITOR;
 228
 229         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 230
 231         if (elems.ds_params && elems.ds_params_len == 1)
 232                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
 233                                                       rx_status->band);
 234         else
 235                 freq = rx_status->freq;
 236
 237         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 238
 239         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 240                 return RX_DROP_MONITOR;
 241
 242         bss = ieee80211_bss_info_update(sdata->local, rx_status,
 243                                         mgmt, skb->len, &elems,
 244                                         channel, beacon);
 245         if (bss)
 246                 ieee80211_rx_bss_put(sdata->local, bss);
 247
 248         if (channel == sdata->local->oper_channel)
 249                 return RX_CONTINUE;
 250
 251         dev_kfree_skb(skb);
 252         return RX_QUEUED;
 253 }
 254
 255 /* return false if no more work */
 256 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 257 {
 258         struct cfg80211_scan_request *req = local->scan_req;
 259         enum ieee80211_band band;
 260         int i, ielen, n_chans;
 261
 262         do {
 263                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 264                         return false;
 265
 266                 band = local->hw_scan_band;
 267                 n_chans = 0;
 268                 for (i = 0; i < req->n_channels; i++) {
 269                         if (req->channels[i]->band == band) {
 270                                 local->hw_scan_req->channels[n_chans] =
 271                                                         req->channels[i];
 272                                 n_chans++;
 273                         }
 274                 }
 275
 276                 local->hw_scan_band++;
 277         } while (!n_chans);
 278
 279         local->hw_scan_req->n_channels = n_chans;
 280
 281         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 282                                          req->ie, req->ie_len, band,
 283                                          req->rates[band], 0);
 284         local->hw_scan_req->ie_len = ielen;
 285         local->hw_scan_req->no_cck = req->no_cck;
 286
 287         return true;
 288 }
 289
 290 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 291                                        bool was_hw_scan)
 292 {
 293         struct ieee80211_local *local = hw_to_local(hw);
 294
 295         lockdep_assert_held(&local->mtx);
 296
 297         /*
 298          * It's ok to abort a not-yet-running scan (that
 299          * we have one at all will be verified by checking
 300          * local->scan_req next), but not to complete it
 301          * successfully.
 302          */
 303         if (WARN_ON(!local->scanning && !aborted))
 304                 aborted = true;
 305
 306         if (WARN_ON(!local->scan_req))
 307                 return;
 308
 309         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 310                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
 311                 if (rc == 0)
 312                         return;
 313         }
 314
 315         kfree(local->hw_scan_req);
 316         local->hw_scan_req = NULL;
 317
 318         if (local->scan_req != local->int_scan_req)
 319                 cfg80211_scan_done(local->scan_req, aborted);
 320         local->scan_req = NULL;
 321         local->scan_sdata = NULL;
 322
 323         local->scanning = 0;
 324         local->scan_channel = NULL;
 325
 326         /* Set power back to normal operating levels. */
 327         ieee80211_hw_config(local, 0);
 328
 329         if (!was_hw_scan) {
 330                 ieee80211_configure_filter(local);
 331                 drv_sw_scan_complete(local);
 332                 ieee80211_offchannel_return(local, true);
 333         }
 334
 335         ieee80211_recalc_idle(local);
 336
 337         ieee80211_mlme_notify_scan_completed(local);
 338         ieee80211_ibss_notify_scan_completed(local);
 339         ieee80211_mesh_notify_scan_completed(local);
 340         ieee80211_queue_work(&local->hw, &local->work_work);
 341 }
 342
 343 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 344 {
 345         struct ieee80211_local *local = hw_to_local(hw);
 346
 347         trace_api_scan_completed(local, aborted);
 348
 349         set_bit(SCAN_COMPLETED, &local->scanning);
 350         if (aborted)
 351                 set_bit(SCAN_ABORTED, &local->scanning);
 352         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 353 }
 354 EXPORT_SYMBOL(ieee80211_scan_completed);
 355
 356 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 357 {
 358         /*
 359          * Hardware/driver doesn't support hw_scan, so use software
 360          * scanning instead. First send a nullfunc frame with power save
 361          * bit on so that AP will buffer the frames for us while we are not
 362          * listening, then send probe requests to each channel and wait for
 363          * the responses. After all channels are scanned, tune back to the
 364          * original channel and send a nullfunc frame with power save bit
 365          * off to trigger the AP to send us all the buffered frames.
 366          *
 367          * Note that while local->sw_scanning is true everything else but
 368          * nullfunc frames and probe requests will be dropped in
 369          * ieee80211_tx_h_check_assoc().
 370          */
 371         drv_sw_scan_start(local);
 372
 373         local->leave_oper_channel_time = jiffies;
 374         local->next_scan_state = SCAN_DECISION;
 375         local->scan_channel_idx = 0;
 376
 377         ieee80211_offchannel_stop_vifs(local, true);
 378
 379         ieee80211_configure_filter(local);
 380
 381         /* We need to set power level at maximum rate for scanning. */
 382         ieee80211_hw_config(local, 0);
 383
 384         ieee80211_queue_delayed_work(&local->hw,
 385                                      &local->scan_work, 0);
 386
 387         return 0;
 388 }
 389
 390 static bool ieee80211_can_scan(struct ieee80211_local *local,
 391                                struct ieee80211_sub_if_data *sdata)
 392 {
 393         if (!list_empty(&local->work_list))
 394                 return false;
 395
 396         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 397             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 398                                   IEEE80211_STA_CONNECTION_POLL))
 399                 return false;
 400
 401         return true;
 402 }
 403
 404 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 405 {
 406         lockdep_assert_held(&local->mtx);
 407
 408         if (!local->scan_req || local->scanning)
 409                 return;
 410
 411         if (!ieee80211_can_scan(local, local->scan_sdata))
 412                 return;
 413
 414         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 415                                      round_jiffies_relative(0));
 416 }
 417
 418 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 419                                   struct cfg80211_scan_request *req)
 420 {
 421         struct ieee80211_local *local = sdata->local;
 422         int rc;
 423
 424         lockdep_assert_held(&local->mtx);
 425
 426         if (local->scan_req)
 427                 return -EBUSY;
 428
 429         if (!ieee80211_can_scan(local, sdata)) {
 430                 /* wait for the work to finish/time out */
 431                 local->scan_req = req;
 432                 local->scan_sdata = sdata;
 433                 return 0;
 434         }
 435
 436         if (local->ops->hw_scan) {
 437                 u8 *ies;
 438
 439                 local->hw_scan_req = kmalloc(
 440                                 sizeof(*local->hw_scan_req) +
 441                                 req->n_channels * sizeof(req->channels[0]) +
 442                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 443                                 req->ie_len, GFP_KERNEL);
 444                 if (!local->hw_scan_req)
 445                         return -ENOMEM;
 446
 447                 local->hw_scan_req->ssids = req->ssids;
 448                 local->hw_scan_req->n_ssids = req->n_ssids;
 449                 ies = (u8 *)local->hw_scan_req +
 450                         sizeof(*local->hw_scan_req) +
 451                         req->n_channels * sizeof(req->channels[0]);
 452                 local->hw_scan_req->ie = ies;
 453
 454                 local->hw_scan_band = 0;
 455
 456                 /*
 457                  * After allocating local->hw_scan_req, we must
 458                  * go through until ieee80211_prep_hw_scan(), so
 459                  * anything that might be changed here and leave
 460                  * this function early must not go after this
 461                  * allocation.
 462                  */
 463         }
 464
 465         local->scan_req = req;
 466         local->scan_sdata = sdata;
 467
 468         if (local->ops->hw_scan)
 469                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 470         else
 471                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 472
 473         ieee80211_recalc_idle(local);
 474
 475         if (local->ops->hw_scan) {
 476                 WARN_ON(!ieee80211_prep_hw_scan(local));
 477                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 478         } else
 479                 rc = ieee80211_start_sw_scan(local);
 480
 481         if (rc) {
 482                 kfree(local->hw_scan_req);
 483                 local->hw_scan_req = NULL;
 484                 local->scanning = 0;
 485
 486                 ieee80211_recalc_idle(local);
 487
 488                 local->scan_req = NULL;
 489                 local->scan_sdata = NULL;
 490         }
 491
 492         return rc;
 493 }
 494
 495 static unsigned long
 496 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 497 {
 498         /*
 499          * TODO: channel switching also consumes quite some time,
 500          * add that delay as well to get a better estimation
 501          */
 502         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 503                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 504         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 505 }
 506
 507 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 508                                           unsigned long *next_delay)
 509 {
 510         bool associated = false;
 511         bool tx_empty = true;
 512         bool bad_latency;
 513         bool listen_int_exceeded;
 514         unsigned long min_beacon_int = 0;
 515         struct ieee80211_sub_if_data *sdata;
 516         struct ieee80211_channel *next_chan;
 517
 518         /*
 519          * check if at least one STA interface is associated,
 520          * check if at least one STA interface has pending tx frames
 521          * and grab the lowest used beacon interval
 522          */
 523         mutex_lock(&local->iflist_mtx);
 524         list_for_each_entry(sdata, &local->interfaces, list) {
 525                 if (!ieee80211_sdata_running(sdata))
 526                         continue;
 527
 528                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 529                         if (sdata->u.mgd.associated) {
 530                                 associated = true;
 531
 532                                 if (sdata->vif.bss_conf.beacon_int <
 533                                     min_beacon_int || min_beacon_int == 0)
 534                                         min_beacon_int =
 535                                                 sdata->vif.bss_conf.beacon_int;
 536
 537                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 538                                         tx_empty = false;
 539                                         break;
 540                                 }
 541                         }
 542                 }
 543         }
 544         mutex_unlock(&local->iflist_mtx);
 545
 546         next_chan = local->scan_req->channels[local->scan_channel_idx];
 547
 548         /*
 549          * we're currently scanning a different channel, let's
 550          * see if we can scan another channel without interfering
 551          * with the current traffic situation.
 552          *
 553          * Since we don't know if the AP has pending frames for us
 554          * we can only check for our tx queues and use the current
 555          * pm_qos requirements for rx. Hence, if no tx traffic occurs
 556          * at all we will scan as many channels in a row as the pm_qos
 557          * latency allows us to. Additionally we also check for the
 558          * currently negotiated listen interval to prevent losing
 559          * frames unnecessarily.
 560          *
 561          * Otherwise switch back to the operating channel.
 562          */
 563
 564         bad_latency = time_after(jiffies +
 565                         ieee80211_scan_get_channel_time(next_chan),
 566                         local->leave_oper_channel_time +
 567                         usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 568
 569         listen_int_exceeded = time_after(jiffies +
 570                         ieee80211_scan_get_channel_time(next_chan),
 571                         local->leave_oper_channel_time +
 572                         usecs_to_jiffies(min_beacon_int * 1024) *
 573                         local->hw.conf.listen_interval);
 574
 575         if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
 576                 local->next_scan_state = SCAN_SUSPEND;
 577         else
 578                 local->next_scan_state = SCAN_SET_CHANNEL;
 579
 580         *next_delay = 0;
 581 }
 582
 583 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 584                                              unsigned long *next_delay)
 585 {
 586         int skip;
 587         struct ieee80211_channel *chan;
 588
 589         skip = 0;
 590         chan = local->scan_req->channels[local->scan_channel_idx];
 591
 592         local->scan_channel = chan;
 593
 594         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 595                 skip = 1;
 596
 597         /* advance state machine to next channel/band */
 598         local->scan_channel_idx++;
 599
 600         if (skip) {
 601                 /* if we skip this channel return to the decision state */
 602                 local->next_scan_state = SCAN_DECISION;
 603                 return;
 604         }
 605
 606         /*
 607          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 608          * (which unfortunately doesn't say _why_ step a) is done,
 609          * but it waits for the probe delay or until a frame is
 610          * received - and the received frame would update the NAV).
 611          * For now, we do not support waiting until a frame is
 612          * received.
 613          *
 614          * In any case, it is not necessary for a passive scan.
 615          */
 616         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 617             !local->scan_req->n_ssids) {
 618                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 619                 local->next_scan_state = SCAN_DECISION;
 620                 return;
 621         }
 622
 623         /* active scan, send probes */
 624         *next_delay = IEEE80211_PROBE_DELAY;
 625         local->next_scan_state = SCAN_SEND_PROBE;
 626 }
 627
 628 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 629                                             unsigned long *next_delay)
 630 {
 631         int i;
 632         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 633         enum ieee80211_band band = local->hw.conf.channel->band;
 634
 635         for (i = 0; i < local->scan_req->n_ssids; i++)
 636                 ieee80211_send_probe_req(
 637                         sdata, NULL,
 638                         local->scan_req->ssids[i].ssid,
 639                         local->scan_req->ssids[i].ssid_len,
 640                         local->scan_req->ie, local->scan_req->ie_len,
 641                         local->scan_req->rates[band], false,
 642                         local->scan_req->no_cck);
 643
 644         /*
 645          * After sending probe requests, wait for probe responses
 646          * on the channel.
 647          */
 648         *next_delay = IEEE80211_CHANNEL_TIME;
 649         local->next_scan_state = SCAN_DECISION;
 650 }
 651
 652 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 653                                          unsigned long *next_delay)
 654 {
 655         /* switch back to the operating channel */
 656         local->scan_channel = NULL;
 657         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 658
 659         /*
 660          * Re-enable vifs and beaconing.  Leave PS
 661          * in off-channel state..will put that back
 662          * on-channel at the end of scanning.
 663          */
 664         ieee80211_offchannel_return(local, false);
 665
 666         *next_delay = HZ / 5;
 667         /* afterwards, resume scan & go to next channel */
 668         local->next_scan_state = SCAN_RESUME;
 669 }
 670
 671 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 672                                         unsigned long *next_delay)
 673 {
 674         /* PS already is in off-channel mode */
 675         ieee80211_offchannel_stop_vifs(local, false);
 676
 677         if (local->ops->flush) {
 678                 drv_flush(local, false);
 679                 *next_delay = 0;
 680         } else
 681                 *next_delay = HZ / 10;
 682
 683         /* remember when we left the operating channel */
 684         local->leave_oper_channel_time = jiffies;
 685
 686         /* advance to the next channel to be scanned */
 687         local->next_scan_state = SCAN_SET_CHANNEL;
 688 }
 689
 690 void ieee80211_scan_work(struct work_struct *work)
 691 {
 692         struct ieee80211_local *local =
 693                 container_of(work, struct ieee80211_local, scan_work.work);
 694         struct ieee80211_sub_if_data *sdata;
 695         unsigned long next_delay = 0;
 696         bool aborted, hw_scan;
 697
 698         mutex_lock(&local->mtx);
 699
 700         sdata = local->scan_sdata;
 701
 702         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 703                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 704                 goto out_complete;
 705         }
 706
 707         if (!sdata || !local->scan_req)
 708                 goto out;
 709
 710         if (local->scan_req && !local->scanning) {
 711                 struct cfg80211_scan_request *req = local->scan_req;
 712                 int rc;
 713
 714                 local->scan_req = NULL;
 715                 local->scan_sdata = NULL;
 716
 717                 rc = __ieee80211_start_scan(sdata, req);
 718                 if (rc) {
 719                         /* need to complete scan in cfg80211 */
 720                         local->scan_req = req;
 721                         aborted = true;
 722                         goto out_complete;
 723                 } else
 724                         goto out;
 725         }
 726
 727         /*
 728          * Avoid re-scheduling when the sdata is going away.
 729          */
 730         if (!ieee80211_sdata_running(sdata)) {
 731                 aborted = true;
 732                 goto out_complete;
 733         }
 734
 735         /*
 736          * as long as no delay is required advance immediately
 737          * without scheduling a new work
 738          */
 739         do {
 740                 if (!ieee80211_sdata_running(sdata)) {
 741                         aborted = true;
 742                         goto out_complete;
 743                 }
 744
 745                 switch (local->next_scan_state) {
 746                 case SCAN_DECISION:
 747                         /* if no more bands/channels left, complete scan */
 748                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 749                                 aborted = false;
 750                                 goto out_complete;
 751                         }
 752                         ieee80211_scan_state_decision(local, &next_delay);
 753                         break;
 754                 case SCAN_SET_CHANNEL:
 755                         ieee80211_scan_state_set_channel(local, &next_delay);
 756                         break;
 757                 case SCAN_SEND_PROBE:
 758                         ieee80211_scan_state_send_probe(local, &next_delay);
 759                         break;
 760                 case SCAN_SUSPEND:
 761                         ieee80211_scan_state_suspend(local, &next_delay);
 762                         break;
 763                 case SCAN_RESUME:
 764                         ieee80211_scan_state_resume(local, &next_delay);
 765                         break;
 766                 }
 767         } while (next_delay == 0);
 768
 769         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 770         goto out;
 771
 772 out_complete:
 773         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 774         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 775 out:
 776         mutex_unlock(&local->mtx);
 777 }
 778
 779 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 780                            struct cfg80211_scan_request *req)
 781 {
 782         int res;
 783
 784         mutex_lock(&sdata->local->mtx);
 785         res = __ieee80211_start_scan(sdata, req);
 786         mutex_unlock(&sdata->local->mtx);
 787
 788         return res;
 789 }
 790
 791 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 792                                     const u8 *ssid, u8 ssid_len,
 793                                     struct ieee80211_channel *chan)
 794 {
 795         struct ieee80211_local *local = sdata->local;
 796         int ret = -EBUSY;
 797         enum ieee80211_band band;
 798
 799         mutex_lock(&local->mtx);
 800
 801         /* busy scanning */
 802         if (local->scan_req)
 803                 goto unlock;
 804
 805         /* fill internal scan request */
 806         if (!chan) {
 807                 int i, nchan = 0;
 808
 809                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 810                         if (!local->hw.wiphy->bands[band])
 811                                 continue;
 812                         for (i = 0;
 813                              i < local->hw.wiphy->bands[band]->n_channels;
 814                              i++) {
 815                                 local->int_scan_req->channels[nchan] =
 816                                     &local->hw.wiphy->bands[band]->channels[i];
 817                                 nchan++;
 818                         }
 819                 }
 820
 821                 local->int_scan_req->n_channels = nchan;
 822         } else {
 823                 local->int_scan_req->channels[0] = chan;
 824                 local->int_scan_req->n_channels = 1;
 825         }
 826
 827         local->int_scan_req->ssids = &local->scan_ssid;
 828         local->int_scan_req->n_ssids = 1;
 829         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 830         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 831
 832         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 833  unlock:
 834         mutex_unlock(&local->mtx);
 835         return ret;
 836 }
 837
 838 /*
 839  * Only call this function when a scan can't be queued -- under RTNL.
 840  */
 841 void ieee80211_scan_cancel(struct ieee80211_local *local)
 842 {
 843         /*
 844          * We are canceling software scan, or deferred scan that was not
 845          * yet really started (see __ieee80211_start_scan ).
 846          *
 847          * Regarding hardware scan:
 848          * - we can not call  __ieee80211_scan_completed() as when
 849          *   SCAN_HW_SCANNING bit is set this function change
 850          *   local->hw_scan_req to operate on 5G band, what race with
 851          *   driver which can use local->hw_scan_req
 852          *
 853          * - we can not cancel scan_work since driver can schedule it
 854          *   by ieee80211_scan_completed(..., true) to finish scan
 855          *
 856          * Hence we only call the cancel_hw_scan() callback, but the low-level
 857          * driver is still responsible for calling ieee80211_scan_completed()
 858          * after the scan was completed/aborted.
 859          */
 860
 861         mutex_lock(&local->mtx);
 862         if (!local->scan_req)
 863                 goto out;
 864
 865         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 866                 if (local->ops->cancel_hw_scan)
 867                         drv_cancel_hw_scan(local, local->scan_sdata);
 868                 goto out;
 869         }
 870
 871         /*
 872          * If the work is currently running, it must be blocked on
 873          * the mutex, but we'll set scan_sdata = NULL and it'll
 874          * simply exit once it acquires the mutex.
 875          */
 876         cancel_delayed_work(&local->scan_work);
 877         /* and clean up */
 878         __ieee80211_scan_completed(&local->hw, true, false);
 879 out:
 880         mutex_unlock(&local->mtx);
 881 }
 882
 883 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 884                                        struct cfg80211_sched_scan_request *req)
 885 {
 886         struct ieee80211_local *local = sdata->local;
 887         int ret, i;
 888
 889         mutex_lock(&sdata->local->mtx);
 890
 891         if (local->sched_scanning) {
 892                 ret = -EBUSY;
 893                 goto out;
 894         }
 895
 896         if (!local->ops->sched_scan_start) {
 897                 ret = -ENOTSUPP;
 898                 goto out;
 899         }
 900
 901         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 902                 local->sched_scan_ies.ie[i] = kzalloc(2 +
 903                                                       IEEE80211_MAX_SSID_LEN +
 904                                                       local->scan_ies_len +
 905                                                       req->ie_len,
 906                                                       GFP_KERNEL);
 907                 if (!local->sched_scan_ies.ie[i]) {
 908                         ret = -ENOMEM;
 909                         goto out_free;
 910                 }
 911
 912                 local->sched_scan_ies.len[i] =
 913                         ieee80211_build_preq_ies(local,
 914                                                  local->sched_scan_ies.ie[i],
 915                                                  req->ie, req->ie_len, i,
 916                                                  (u32) -1, 0);
 917         }
 918
 919         ret = drv_sched_scan_start(local, sdata, req,
 920                                    &local->sched_scan_ies);
 921         if (ret == 0) {
 922                 local->sched_scanning = true;
 923                 goto out;
 924         }
 925
 926 out_free:
 927         while (i > 0)
 928                 kfree(local->sched_scan_ies.ie[--i]);
 929 out:
 930         mutex_unlock(&sdata->local->mtx);
 931         return ret;
 932 }
 933
 934 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 935 {
 936         struct ieee80211_local *local = sdata->local;
 937         int ret = 0, i;
 938
 939         mutex_lock(&sdata->local->mtx);
 940
 941         if (!local->ops->sched_scan_stop) {
 942                 ret = -ENOTSUPP;
 943                 goto out;
 944         }
 945
 946         if (local->sched_scanning) {
 947                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 948                         kfree(local->sched_scan_ies.ie[i]);
 949
 950                 drv_sched_scan_stop(local, sdata);
 951                 local->sched_scanning = false;
 952         }
 953 out:
 954         mutex_unlock(&sdata->local->mtx);
 955
 956         return ret;
 957 }
 958
 959 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 960 {
 961         struct ieee80211_local *local = hw_to_local(hw);
 962
 963         trace_api_sched_scan_results(local);
 964
 965         cfg80211_sched_scan_results(hw->wiphy);
 966 }
 967 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 968
 969 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 970 {
 971         struct ieee80211_local *local =
 972                 container_of(work, struct ieee80211_local,
 973                              sched_scan_stopped_work);
 974         int i;
 975
 976         mutex_lock(&local->mtx);
 977
 978         if (!local->sched_scanning) {
 979                 mutex_unlock(&local->mtx);
 980                 return;
 981         }
 982
 983         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 984                 kfree(local->sched_scan_ies.ie[i]);
 985
 986         local->sched_scanning = false;
 987
 988         mutex_unlock(&local->mtx);
 989
 990         cfg80211_sched_scan_stopped(local->hw.wiphy);
 991 }
 992
 993 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
 994 {
 995         struct ieee80211_local *local = hw_to_local(hw);
 996
 997         trace_api_sched_scan_stopped(local);
 998
 999         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1000 }
1001 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);