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