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         dev_kfree_skb(skb);
 217         return RX_QUEUED;
 218 }
 219
 220 /* return false if no more work */
 221 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 222 {
 223         struct cfg80211_scan_request *req = local->scan_req;
 224         enum ieee80211_band band;
 225         int i, ielen, n_chans;
 226
 227         do {
 228                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 229                         return false;
 230
 231                 band = local->hw_scan_band;
 232                 n_chans = 0;
 233                 for (i = 0; i < req->n_channels; i++) {
 234                         if (req->channels[i]->band == band) {
 235                                 local->hw_scan_req->channels[n_chans] =
 236                                                         req->channels[i];
 237                                 n_chans++;
 238                         }
 239                 }
 240
 241                 local->hw_scan_band++;
 242         } while (!n_chans);
 243
 244         local->hw_scan_req->n_channels = n_chans;
 245
 246         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 247                                          req->ie, req->ie_len, band,
 248                                          req->rates[band], 0);
 249         local->hw_scan_req->ie_len = ielen;
 250         local->hw_scan_req->no_cck = req->no_cck;
 251
 252         return true;
 253 }
 254
 255 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 256                                        bool was_hw_scan)
 257 {
 258         struct ieee80211_local *local = hw_to_local(hw);
 259
 260         lockdep_assert_held(&local->mtx);
 261
 262         /*
 263          * It's ok to abort a not-yet-running scan (that
 264          * we have one at all will be verified by checking
 265          * local->scan_req next), but not to complete it
 266          * successfully.
 267          */
 268         if (WARN_ON(!local->scanning && !aborted))
 269                 aborted = true;
 270
 271         if (WARN_ON(!local->scan_req))
 272                 return;
 273
 274         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 275                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
 276                 if (rc == 0)
 277                         return;
 278         }
 279
 280         kfree(local->hw_scan_req);
 281         local->hw_scan_req = NULL;
 282
 283         if (local->scan_req != local->int_scan_req)
 284                 cfg80211_scan_done(local->scan_req, aborted);
 285         local->scan_req = NULL;
 286         local->scan_sdata = NULL;
 287
 288         local->scanning = 0;
 289         local->scan_channel = NULL;
 290
 291         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 292         if (!was_hw_scan) {
 293                 ieee80211_configure_filter(local);
 294                 drv_sw_scan_complete(local);
 295                 ieee80211_offchannel_return(local, true);
 296         }
 297
 298         ieee80211_recalc_idle(local);
 299
 300         ieee80211_mlme_notify_scan_completed(local);
 301         ieee80211_ibss_notify_scan_completed(local);
 302         ieee80211_mesh_notify_scan_completed(local);
 303         ieee80211_queue_work(&local->hw, &local->work_work);
 304 }
 305
 306 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 307 {
 308         struct ieee80211_local *local = hw_to_local(hw);
 309
 310         trace_api_scan_completed(local, aborted);
 311
 312         set_bit(SCAN_COMPLETED, &local->scanning);
 313         if (aborted)
 314                 set_bit(SCAN_ABORTED, &local->scanning);
 315         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 316 }
 317 EXPORT_SYMBOL(ieee80211_scan_completed);
 318
 319 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 320 {
 321         /*
 322          * Hardware/driver doesn't support hw_scan, so use software
 323          * scanning instead. First send a nullfunc frame with power save
 324          * bit on so that AP will buffer the frames for us while we are not
 325          * listening, then send probe requests to each channel and wait for
 326          * the responses. After all channels are scanned, tune back to the
 327          * original channel and send a nullfunc frame with power save bit
 328          * off to trigger the AP to send us all the buffered frames.
 329          *
 330          * Note that while local->sw_scanning is true everything else but
 331          * nullfunc frames and probe requests will be dropped in
 332          * ieee80211_tx_h_check_assoc().
 333          */
 334         drv_sw_scan_start(local);
 335
 336         ieee80211_offchannel_stop_beaconing(local);
 337
 338         local->leave_oper_channel_time = 0;
 339         local->next_scan_state = SCAN_DECISION;
 340         local->scan_channel_idx = 0;
 341
 342         drv_flush(local, false);
 343
 344         ieee80211_configure_filter(local);
 345
 346         /* We need to set power level at maximum rate for scanning. */
 347         ieee80211_hw_config(local, 0);
 348
 349         ieee80211_queue_delayed_work(&local->hw,
 350                                      &local->scan_work,
 351                                      IEEE80211_CHANNEL_TIME);
 352
 353         return 0;
 354 }
 355
 356
 357 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 358                                   struct cfg80211_scan_request *req)
 359 {
 360         struct ieee80211_local *local = sdata->local;
 361         int rc;
 362
 363         lockdep_assert_held(&local->mtx);
 364
 365         if (local->scan_req)
 366                 return -EBUSY;
 367
 368         if (!list_empty(&local->work_list)) {
 369                 /* wait for the work to finish/time out */
 370                 local->scan_req = req;
 371                 local->scan_sdata = sdata;
 372                 return 0;
 373         }
 374
 375         if (local->ops->hw_scan) {
 376                 u8 *ies;
 377
 378                 local->hw_scan_req = kmalloc(
 379                                 sizeof(*local->hw_scan_req) +
 380                                 req->n_channels * sizeof(req->channels[0]) +
 381                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 382                                 req->ie_len, GFP_KERNEL);
 383                 if (!local->hw_scan_req)
 384                         return -ENOMEM;
 385
 386                 local->hw_scan_req->ssids = req->ssids;
 387                 local->hw_scan_req->n_ssids = req->n_ssids;
 388                 ies = (u8 *)local->hw_scan_req +
 389                         sizeof(*local->hw_scan_req) +
 390                         req->n_channels * sizeof(req->channels[0]);
 391                 local->hw_scan_req->ie = ies;
 392
 393                 local->hw_scan_band = 0;
 394
 395                 /*
 396                  * After allocating local->hw_scan_req, we must
 397                  * go through until ieee80211_prep_hw_scan(), so
 398                  * anything that might be changed here and leave
 399                  * this function early must not go after this
 400                  * allocation.
 401                  */
 402         }
 403
 404         local->scan_req = req;
 405         local->scan_sdata = sdata;
 406
 407         if (local->ops->hw_scan)
 408                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 409         else
 410                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 411
 412         ieee80211_recalc_idle(local);
 413
 414         if (local->ops->hw_scan) {
 415                 WARN_ON(!ieee80211_prep_hw_scan(local));
 416                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 417         } else
 418                 rc = ieee80211_start_sw_scan(local);
 419
 420         if (rc) {
 421                 kfree(local->hw_scan_req);
 422                 local->hw_scan_req = NULL;
 423                 local->scanning = 0;
 424
 425                 ieee80211_recalc_idle(local);
 426
 427                 local->scan_req = NULL;
 428                 local->scan_sdata = NULL;
 429         }
 430
 431         return rc;
 432 }
 433
 434 static unsigned long
 435 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 436 {
 437         /*
 438          * TODO: channel switching also consumes quite some time,
 439          * add that delay as well to get a better estimation
 440          */
 441         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 442                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 443         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 444 }
 445
 446 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 447                                           unsigned long *next_delay)
 448 {
 449         bool associated = false;
 450         bool tx_empty = true;
 451         bool bad_latency;
 452         bool listen_int_exceeded;
 453         unsigned long min_beacon_int = 0;
 454         struct ieee80211_sub_if_data *sdata;
 455         struct ieee80211_channel *next_chan;
 456
 457         /*
 458          * check if at least one STA interface is associated,
 459          * check if at least one STA interface has pending tx frames
 460          * and grab the lowest used beacon interval
 461          */
 462         mutex_lock(&local->iflist_mtx);
 463         list_for_each_entry(sdata, &local->interfaces, list) {
 464                 if (!ieee80211_sdata_running(sdata))
 465                         continue;
 466
 467                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 468                         if (sdata->u.mgd.associated) {
 469                                 associated = true;
 470
 471                                 if (sdata->vif.bss_conf.beacon_int <
 472                                     min_beacon_int || min_beacon_int == 0)
 473                                         min_beacon_int =
 474                                                 sdata->vif.bss_conf.beacon_int;
 475
 476                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 477                                         tx_empty = false;
 478                                         break;
 479                                 }
 480                         }
 481                 }
 482         }
 483         mutex_unlock(&local->iflist_mtx);
 484
 485         if (local->scan_channel) {
 486                 /*
 487                  * we're currently scanning a different channel, let's
 488                  * see if we can scan another channel without interfering
 489                  * with the current traffic situation.
 490                  *
 491                  * Since we don't know if the AP has pending frames for us
 492                  * we can only check for our tx queues and use the current
 493                  * pm_qos requirements for rx. Hence, if no tx traffic occurs
 494                  * at all we will scan as many channels in a row as the pm_qos
 495                  * latency allows us to. Additionally we also check for the
 496                  * currently negotiated listen interval to prevent losing
 497                  * frames unnecessarily.
 498                  *
 499                  * Otherwise switch back to the operating channel.
 500                  */
 501                 next_chan = local->scan_req->channels[local->scan_channel_idx];
 502
 503                 bad_latency = time_after(jiffies +
 504                                 ieee80211_scan_get_channel_time(next_chan),
 505                                 local->leave_oper_channel_time +
 506                                 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 507
 508                 listen_int_exceeded = time_after(jiffies +
 509                                 ieee80211_scan_get_channel_time(next_chan),
 510                                 local->leave_oper_channel_time +
 511                                 usecs_to_jiffies(min_beacon_int * 1024) *
 512                                 local->hw.conf.listen_interval);
 513
 514                 if (associated && ( !tx_empty || bad_latency ||
 515                     listen_int_exceeded))
 516                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
 517                 else
 518                         local->next_scan_state = SCAN_SET_CHANNEL;
 519         } else {
 520                 /*
 521                  * we're on the operating channel currently, let's
 522                  * leave that channel now to scan another one
 523                  */
 524                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
 525         }
 526
 527         *next_delay = 0;
 528 }
 529
 530 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
 531                                                     unsigned long *next_delay)
 532 {
 533         ieee80211_offchannel_stop_station(local);
 534
 535         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
 536
 537         /*
 538          * What if the nullfunc frames didn't arrive?
 539          */
 540         drv_flush(local, false);
 541         if (local->ops->flush)
 542                 *next_delay = 0;
 543         else
 544                 *next_delay = HZ / 10;
 545
 546         /* remember when we left the operating channel */
 547         local->leave_oper_channel_time = jiffies;
 548
 549         /* advance to the next channel to be scanned */
 550         local->next_scan_state = SCAN_SET_CHANNEL;
 551 }
 552
 553 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
 554                                                     unsigned long *next_delay)
 555 {
 556         /* switch back to the operating channel */
 557         local->scan_channel = NULL;
 558         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 559
 560         /*
 561          * Only re-enable station mode interface now; beaconing will be
 562          * re-enabled once the full scan has been completed.
 563          */
 564         ieee80211_offchannel_return(local, false);
 565
 566         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
 567
 568         *next_delay = HZ / 5;
 569         local->next_scan_state = SCAN_DECISION;
 570 }
 571
 572 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 573                                              unsigned long *next_delay)
 574 {
 575         int skip;
 576         struct ieee80211_channel *chan;
 577
 578         skip = 0;
 579         chan = local->scan_req->channels[local->scan_channel_idx];
 580
 581         local->scan_channel = chan;
 582
 583         /* Only call hw-config if we really need to change channels. */
 584         if (chan != local->hw.conf.channel)
 585                 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 586                         skip = 1;
 587
 588         /* advance state machine to next channel/band */
 589         local->scan_channel_idx++;
 590
 591         if (skip) {
 592                 /* if we skip this channel return to the decision state */
 593                 local->next_scan_state = SCAN_DECISION;
 594                 return;
 595         }
 596
 597         /*
 598          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 599          * (which unfortunately doesn't say _why_ step a) is done,
 600          * but it waits for the probe delay or until a frame is
 601          * received - and the received frame would update the NAV).
 602          * For now, we do not support waiting until a frame is
 603          * received.
 604          *
 605          * In any case, it is not necessary for a passive scan.
 606          */
 607         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 608             !local->scan_req->n_ssids) {
 609                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 610                 local->next_scan_state = SCAN_DECISION;
 611                 return;
 612         }
 613
 614         /* active scan, send probes */
 615         *next_delay = IEEE80211_PROBE_DELAY;
 616         local->next_scan_state = SCAN_SEND_PROBE;
 617 }
 618
 619 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 620                                             unsigned long *next_delay)
 621 {
 622         int i;
 623         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 624         enum ieee80211_band band = local->hw.conf.channel->band;
 625
 626         for (i = 0; i < local->scan_req->n_ssids; i++)
 627                 ieee80211_send_probe_req(
 628                         sdata, NULL,
 629                         local->scan_req->ssids[i].ssid,
 630                         local->scan_req->ssids[i].ssid_len,
 631                         local->scan_req->ie, local->scan_req->ie_len,
 632                         local->scan_req->rates[band], false,
 633                         local->scan_req->no_cck);
 634
 635         /*
 636          * After sending probe requests, wait for probe responses
 637          * on the channel.
 638          */
 639         *next_delay = IEEE80211_CHANNEL_TIME;
 640         local->next_scan_state = SCAN_DECISION;
 641 }
 642
 643 void ieee80211_scan_work(struct work_struct *work)
 644 {
 645         struct ieee80211_local *local =
 646                 container_of(work, struct ieee80211_local, scan_work.work);
 647         struct ieee80211_sub_if_data *sdata;
 648         unsigned long next_delay = 0;
 649         bool aborted, hw_scan;
 650
 651         mutex_lock(&local->mtx);
 652
 653         sdata = local->scan_sdata;
 654
 655         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 656                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 657                 goto out_complete;
 658         }
 659
 660         if (!sdata || !local->scan_req)
 661                 goto out;
 662
 663         if (local->scan_req && !local->scanning) {
 664                 struct cfg80211_scan_request *req = local->scan_req;
 665                 int rc;
 666
 667                 local->scan_req = NULL;
 668                 local->scan_sdata = NULL;
 669
 670                 rc = __ieee80211_start_scan(sdata, req);
 671                 if (rc) {
 672                         /* need to complete scan in cfg80211 */
 673                         local->scan_req = req;
 674                         aborted = true;
 675                         goto out_complete;
 676                 } else
 677                         goto out;
 678         }
 679
 680         /*
 681          * Avoid re-scheduling when the sdata is going away.
 682          */
 683         if (!ieee80211_sdata_running(sdata)) {
 684                 aborted = true;
 685                 goto out_complete;
 686         }
 687
 688         /*
 689          * as long as no delay is required advance immediately
 690          * without scheduling a new work
 691          */
 692         do {
 693                 if (!ieee80211_sdata_running(sdata)) {
 694                         aborted = true;
 695                         goto out_complete;
 696                 }
 697
 698                 switch (local->next_scan_state) {
 699                 case SCAN_DECISION:
 700                         /* if no more bands/channels left, complete scan */
 701                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 702                                 aborted = false;
 703                                 goto out_complete;
 704                         }
 705                         ieee80211_scan_state_decision(local, &next_delay);
 706                         break;
 707                 case SCAN_SET_CHANNEL:
 708                         ieee80211_scan_state_set_channel(local, &next_delay);
 709                         break;
 710                 case SCAN_SEND_PROBE:
 711                         ieee80211_scan_state_send_probe(local, &next_delay);
 712                         break;
 713                 case SCAN_LEAVE_OPER_CHANNEL:
 714                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
 715                         break;
 716                 case SCAN_ENTER_OPER_CHANNEL:
 717                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 718                         break;
 719                 }
 720         } while (next_delay == 0);
 721
 722         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 723         goto out;
 724
 725 out_complete:
 726         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 727         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 728 out:
 729         mutex_unlock(&local->mtx);
 730 }
 731
 732 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 733                            struct cfg80211_scan_request *req)
 734 {
 735         int res;
 736
 737         mutex_lock(&sdata->local->mtx);
 738         res = __ieee80211_start_scan(sdata, req);
 739         mutex_unlock(&sdata->local->mtx);
 740
 741         return res;
 742 }
 743
 744 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 745                                     const u8 *ssid, u8 ssid_len,
 746                                     struct ieee80211_channel *chan)
 747 {
 748         struct ieee80211_local *local = sdata->local;
 749         int ret = -EBUSY;
 750         enum ieee80211_band band;
 751
 752         mutex_lock(&local->mtx);
 753
 754         /* busy scanning */
 755         if (local->scan_req)
 756                 goto unlock;
 757
 758         /* fill internal scan request */
 759         if (!chan) {
 760                 int i, nchan = 0;
 761
 762                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 763                         if (!local->hw.wiphy->bands[band])
 764                                 continue;
 765                         for (i = 0;
 766                              i < local->hw.wiphy->bands[band]->n_channels;
 767                              i++) {
 768                                 local->int_scan_req->channels[nchan] =
 769                                     &local->hw.wiphy->bands[band]->channels[i];
 770                                 nchan++;
 771                         }
 772                 }
 773
 774                 local->int_scan_req->n_channels = nchan;
 775         } else {
 776                 local->int_scan_req->channels[0] = chan;
 777                 local->int_scan_req->n_channels = 1;
 778         }
 779
 780         local->int_scan_req->ssids = &local->scan_ssid;
 781         local->int_scan_req->n_ssids = 1;
 782         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 783         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 784
 785         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 786  unlock:
 787         mutex_unlock(&local->mtx);
 788         return ret;
 789 }
 790
 791 /*
 792  * Only call this function when a scan can't be queued -- under RTNL.
 793  */
 794 void ieee80211_scan_cancel(struct ieee80211_local *local)
 795 {
 796         /*
 797          * We are canceling software scan, or deferred scan that was not
 798          * yet really started (see __ieee80211_start_scan ).
 799          *
 800          * Regarding hardware scan:
 801          * - we can not call  __ieee80211_scan_completed() as when
 802          *   SCAN_HW_SCANNING bit is set this function change
 803          *   local->hw_scan_req to operate on 5G band, what race with
 804          *   driver which can use local->hw_scan_req
 805          *
 806          * - we can not cancel scan_work since driver can schedule it
 807          *   by ieee80211_scan_completed(..., true) to finish scan
 808          *
 809          * Hence we only call the cancel_hw_scan() callback, but the low-level
 810          * driver is still responsible for calling ieee80211_scan_completed()
 811          * after the scan was completed/aborted.
 812          */
 813
 814         mutex_lock(&local->mtx);
 815         if (!local->scan_req)
 816                 goto out;
 817
 818         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 819                 if (local->ops->cancel_hw_scan)
 820                         drv_cancel_hw_scan(local, local->scan_sdata);
 821                 goto out;
 822         }
 823
 824         /*
 825          * If the work is currently running, it must be blocked on
 826          * the mutex, but we'll set scan_sdata = NULL and it'll
 827          * simply exit once it acquires the mutex.
 828          */
 829         cancel_delayed_work(&local->scan_work);
 830         /* and clean up */
 831         __ieee80211_scan_completed(&local->hw, true, false);
 832 out:
 833         mutex_unlock(&local->mtx);
 834 }
 835
 836 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 837                                        struct cfg80211_sched_scan_request *req)
 838 {
 839         struct ieee80211_local *local = sdata->local;
 840         int ret, i;
 841
 842         mutex_lock(&sdata->local->mtx);
 843
 844         if (local->sched_scanning) {
 845                 ret = -EBUSY;
 846                 goto out;
 847         }
 848
 849         if (!local->ops->sched_scan_start) {
 850                 ret = -ENOTSUPP;
 851                 goto out;
 852         }
 853
 854         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 855                 local->sched_scan_ies.ie[i] = kzalloc(2 +
 856                                                       IEEE80211_MAX_SSID_LEN +
 857                                                       local->scan_ies_len +
 858                                                       req->ie_len,
 859                                                       GFP_KERNEL);
 860                 if (!local->sched_scan_ies.ie[i]) {
 861                         ret = -ENOMEM;
 862                         goto out_free;
 863                 }
 864
 865                 local->sched_scan_ies.len[i] =
 866                         ieee80211_build_preq_ies(local,
 867                                                  local->sched_scan_ies.ie[i],
 868                                                  req->ie, req->ie_len, i,
 869                                                  (u32) -1, 0);
 870         }
 871
 872         ret = drv_sched_scan_start(local, sdata, req,
 873                                    &local->sched_scan_ies);
 874         if (ret == 0) {
 875                 local->sched_scanning = true;
 876                 goto out;
 877         }
 878
 879 out_free:
 880         while (i > 0)
 881                 kfree(local->sched_scan_ies.ie[--i]);
 882 out:
 883         mutex_unlock(&sdata->local->mtx);
 884         return ret;
 885 }
 886
 887 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 888 {
 889         struct ieee80211_local *local = sdata->local;
 890         int ret = 0, i;
 891
 892         mutex_lock(&sdata->local->mtx);
 893
 894         if (!local->ops->sched_scan_stop) {
 895                 ret = -ENOTSUPP;
 896                 goto out;
 897         }
 898
 899         if (local->sched_scanning) {
 900                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 901                         kfree(local->sched_scan_ies.ie[i]);
 902
 903                 drv_sched_scan_stop(local, sdata);
 904                 local->sched_scanning = false;
 905         }
 906 out:
 907         mutex_unlock(&sdata->local->mtx);
 908
 909         return ret;
 910 }
 911
 912 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 913 {
 914         struct ieee80211_local *local = hw_to_local(hw);
 915
 916         trace_api_sched_scan_results(local);
 917
 918         cfg80211_sched_scan_results(hw->wiphy);
 919 }
 920 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 921
 922 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 923 {
 924         struct ieee80211_local *local =
 925                 container_of(work, struct ieee80211_local,
 926                              sched_scan_stopped_work);
 927         int i;
 928
 929         mutex_lock(&local->mtx);
 930
 931         if (!local->sched_scanning) {
 932                 mutex_unlock(&local->mtx);
 933                 return;
 934         }
 935
 936         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 937                 kfree(local->sched_scan_ies.ie[i]);
 938
 939         local->sched_scanning = false;
 940
 941         mutex_unlock(&local->mtx);
 942
 943         cfg80211_sched_scan_stopped(local->hw.wiphy);
 944 }
 945
 946 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
 947 {
 948         struct ieee80211_local *local = hw_to_local(hw);
 949
 950         trace_api_sched_scan_stopped(local);
 951
 952         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
 953 }
 954 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);