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         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 228                 return false;
 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         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 295         if (!was_hw_scan) {
 296                 ieee80211_configure_filter(local);
 297                 drv_sw_scan_complete(local);
 298                 ieee80211_offchannel_return(local, true);
 299         }
 300
 301         ieee80211_recalc_idle(local);
 302
 303         ieee80211_mlme_notify_scan_completed(local);
 304         ieee80211_ibss_notify_scan_completed(local);
 305         ieee80211_mesh_notify_scan_completed(local);
 306         ieee80211_queue_work(&local->hw, &local->work_work);
 307 }
 308
 309 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 310 {
 311         struct ieee80211_local *local = hw_to_local(hw);
 312
 313         trace_api_scan_completed(local, aborted);
 314
 315         set_bit(SCAN_COMPLETED, &local->scanning);
 316         if (aborted)
 317                 set_bit(SCAN_ABORTED, &local->scanning);
 318         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 319 }
 320 EXPORT_SYMBOL(ieee80211_scan_completed);
 321
 322 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 323 {
 324         /*
 325          * Hardware/driver doesn't support hw_scan, so use software
 326          * scanning instead. First send a nullfunc frame with power save
 327          * bit on so that AP will buffer the frames for us while we are not
 328          * listening, then send probe requests to each channel and wait for
 329          * the responses. After all channels are scanned, tune back to the
 330          * original channel and send a nullfunc frame with power save bit
 331          * off to trigger the AP to send us all the buffered frames.
 332          *
 333          * Note that while local->sw_scanning is true everything else but
 334          * nullfunc frames and probe requests will be dropped in
 335          * ieee80211_tx_h_check_assoc().
 336          */
 337         drv_sw_scan_start(local);
 338
 339         ieee80211_offchannel_stop_beaconing(local);
 340
 341         local->leave_oper_channel_time = 0;
 342         local->next_scan_state = SCAN_DECISION;
 343         local->scan_channel_idx = 0;
 344
 345         drv_flush(local, false);
 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,
 354                                      IEEE80211_CHANNEL_TIME);
 355
 356         return 0;
 357 }
 358
 359
 360 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 361                                   struct cfg80211_scan_request *req)
 362 {
 363         struct ieee80211_local *local = sdata->local;
 364         int rc;
 365
 366         lockdep_assert_held(&local->mtx);
 367
 368         if (local->scan_req)
 369                 return -EBUSY;
 370
 371         if (!list_empty(&local->work_list)) {
 372                 /* wait for the work to finish/time out */
 373                 local->scan_req = req;
 374                 local->scan_sdata = sdata;
 375                 return 0;
 376         }
 377
 378         if (local->ops->hw_scan) {
 379                 u8 *ies;
 380
 381                 local->hw_scan_req = kmalloc(
 382                                 sizeof(*local->hw_scan_req) +
 383                                 req->n_channels * sizeof(req->channels[0]) +
 384                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 385                                 req->ie_len, GFP_KERNEL);
 386                 if (!local->hw_scan_req)
 387                         return -ENOMEM;
 388
 389                 local->hw_scan_req->ssids = req->ssids;
 390                 local->hw_scan_req->n_ssids = req->n_ssids;
 391                 ies = (u8 *)local->hw_scan_req +
 392                         sizeof(*local->hw_scan_req) +
 393                         req->n_channels * sizeof(req->channels[0]);
 394                 local->hw_scan_req->ie = ies;
 395
 396                 local->hw_scan_band = 0;
 397
 398                 /*
 399                  * After allocating local->hw_scan_req, we must
 400                  * go through until ieee80211_prep_hw_scan(), so
 401                  * anything that might be changed here and leave
 402                  * this function early must not go after this
 403                  * allocation.
 404                  */
 405         }
 406
 407         local->scan_req = req;
 408         local->scan_sdata = sdata;
 409
 410         if (local->ops->hw_scan)
 411                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 412         else
 413                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 414
 415         ieee80211_recalc_idle(local);
 416
 417         if (local->ops->hw_scan) {
 418                 WARN_ON(!ieee80211_prep_hw_scan(local));
 419                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 420         } else
 421                 rc = ieee80211_start_sw_scan(local);
 422
 423         if (rc) {
 424                 kfree(local->hw_scan_req);
 425                 local->hw_scan_req = NULL;
 426                 local->scanning = 0;
 427
 428                 ieee80211_recalc_idle(local);
 429
 430                 local->scan_req = NULL;
 431                 local->scan_sdata = NULL;
 432         }
 433
 434         return rc;
 435 }
 436
 437 static unsigned long
 438 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 439 {
 440         /*
 441          * TODO: channel switching also consumes quite some time,
 442          * add that delay as well to get a better estimation
 443          */
 444         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 445                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 446         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 447 }
 448
 449 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 450                                           unsigned long *next_delay)
 451 {
 452         bool associated = false;
 453         bool tx_empty = true;
 454         bool bad_latency;
 455         bool listen_int_exceeded;
 456         unsigned long min_beacon_int = 0;
 457         struct ieee80211_sub_if_data *sdata;
 458         struct ieee80211_channel *next_chan;
 459
 460         /*
 461          * check if at least one STA interface is associated,
 462          * check if at least one STA interface has pending tx frames
 463          * and grab the lowest used beacon interval
 464          */
 465         mutex_lock(&local->iflist_mtx);
 466         list_for_each_entry(sdata, &local->interfaces, list) {
 467                 if (!ieee80211_sdata_running(sdata))
 468                         continue;
 469
 470                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 471                         if (sdata->u.mgd.associated) {
 472                                 associated = true;
 473
 474                                 if (sdata->vif.bss_conf.beacon_int <
 475                                     min_beacon_int || min_beacon_int == 0)
 476                                         min_beacon_int =
 477                                                 sdata->vif.bss_conf.beacon_int;
 478
 479                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 480                                         tx_empty = false;
 481                                         break;
 482                                 }
 483                         }
 484                 }
 485         }
 486         mutex_unlock(&local->iflist_mtx);
 487
 488         if (local->scan_channel) {
 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                 next_chan = local->scan_req->channels[local->scan_channel_idx];
 505
 506                 bad_latency = time_after(jiffies +
 507                                 ieee80211_scan_get_channel_time(next_chan),
 508                                 local->leave_oper_channel_time +
 509                                 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 510
 511                 listen_int_exceeded = time_after(jiffies +
 512                                 ieee80211_scan_get_channel_time(next_chan),
 513                                 local->leave_oper_channel_time +
 514                                 usecs_to_jiffies(min_beacon_int * 1024) *
 515                                 local->hw.conf.listen_interval);
 516
 517                 if (associated && ( !tx_empty || bad_latency ||
 518                     listen_int_exceeded))
 519                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
 520                 else
 521                         local->next_scan_state = SCAN_SET_CHANNEL;
 522         } else {
 523                 /*
 524                  * we're on the operating channel currently, let's
 525                  * leave that channel now to scan another one
 526                  */
 527                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
 528         }
 529
 530         *next_delay = 0;
 531 }
 532
 533 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
 534                                                     unsigned long *next_delay)
 535 {
 536         ieee80211_offchannel_stop_station(local);
 537
 538         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
 539
 540         /*
 541          * What if the nullfunc frames didn't arrive?
 542          */
 543         drv_flush(local, false);
 544         if (local->ops->flush)
 545                 *next_delay = 0;
 546         else
 547                 *next_delay = HZ / 10;
 548
 549         /* remember when we left the operating channel */
 550         local->leave_oper_channel_time = jiffies;
 551
 552         /* advance to the next channel to be scanned */
 553         local->next_scan_state = SCAN_SET_CHANNEL;
 554 }
 555
 556 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
 557                                                     unsigned long *next_delay)
 558 {
 559         /* switch back to the operating channel */
 560         local->scan_channel = NULL;
 561         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 562
 563         /*
 564          * Only re-enable station mode interface now; beaconing will be
 565          * re-enabled once the full scan has been completed.
 566          */
 567         ieee80211_offchannel_return(local, false);
 568
 569         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
 570
 571         *next_delay = HZ / 5;
 572         local->next_scan_state = SCAN_DECISION;
 573 }
 574
 575 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 576                                              unsigned long *next_delay)
 577 {
 578         int skip;
 579         struct ieee80211_channel *chan;
 580
 581         skip = 0;
 582         chan = local->scan_req->channels[local->scan_channel_idx];
 583
 584         local->scan_channel = chan;
 585
 586         /* Only call hw-config if we really need to change channels. */
 587         if (chan != local->hw.conf.channel)
 588                 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 589                         skip = 1;
 590
 591         /* advance state machine to next channel/band */
 592         local->scan_channel_idx++;
 593
 594         if (skip) {
 595                 /* if we skip this channel return to the decision state */
 596                 local->next_scan_state = SCAN_DECISION;
 597                 return;
 598         }
 599
 600         /*
 601          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 602          * (which unfortunately doesn't say _why_ step a) is done,
 603          * but it waits for the probe delay or until a frame is
 604          * received - and the received frame would update the NAV).
 605          * For now, we do not support waiting until a frame is
 606          * received.
 607          *
 608          * In any case, it is not necessary for a passive scan.
 609          */
 610         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 611             !local->scan_req->n_ssids) {
 612                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 613                 local->next_scan_state = SCAN_DECISION;
 614                 return;
 615         }
 616
 617         /* active scan, send probes */
 618         *next_delay = IEEE80211_PROBE_DELAY;
 619         local->next_scan_state = SCAN_SEND_PROBE;
 620 }
 621
 622 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 623                                             unsigned long *next_delay)
 624 {
 625         int i;
 626         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 627         enum ieee80211_band band = local->hw.conf.channel->band;
 628
 629         for (i = 0; i < local->scan_req->n_ssids; i++)
 630                 ieee80211_send_probe_req(
 631                         sdata, NULL,
 632                         local->scan_req->ssids[i].ssid,
 633                         local->scan_req->ssids[i].ssid_len,
 634                         local->scan_req->ie, local->scan_req->ie_len,
 635                         local->scan_req->rates[band], false,
 636                         local->scan_req->no_cck);
 637
 638         /*
 639          * After sending probe requests, wait for probe responses
 640          * on the channel.
 641          */
 642         *next_delay = IEEE80211_CHANNEL_TIME;
 643         local->next_scan_state = SCAN_DECISION;
 644 }
 645
 646 void ieee80211_scan_work(struct work_struct *work)
 647 {
 648         struct ieee80211_local *local =
 649                 container_of(work, struct ieee80211_local, scan_work.work);
 650         struct ieee80211_sub_if_data *sdata;
 651         unsigned long next_delay = 0;
 652         bool aborted, hw_scan;
 653
 654         mutex_lock(&local->mtx);
 655
 656         sdata = local->scan_sdata;
 657
 658         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 659                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 660                 goto out_complete;
 661         }
 662
 663         if (!sdata || !local->scan_req)
 664                 goto out;
 665
 666         if (local->scan_req && !local->scanning) {
 667                 struct cfg80211_scan_request *req = local->scan_req;
 668                 int rc;
 669
 670                 local->scan_req = NULL;
 671                 local->scan_sdata = NULL;
 672
 673                 rc = __ieee80211_start_scan(sdata, req);
 674                 if (rc) {
 675                         /* need to complete scan in cfg80211 */
 676                         local->scan_req = req;
 677                         aborted = true;
 678                         goto out_complete;
 679                 } else
 680                         goto out;
 681         }
 682
 683         /*
 684          * Avoid re-scheduling when the sdata is going away.
 685          */
 686         if (!ieee80211_sdata_running(sdata)) {
 687                 aborted = true;
 688                 goto out_complete;
 689         }
 690
 691         /*
 692          * as long as no delay is required advance immediately
 693          * without scheduling a new work
 694          */
 695         do {
 696                 if (!ieee80211_sdata_running(sdata)) {
 697                         aborted = true;
 698                         goto out_complete;
 699                 }
 700
 701                 switch (local->next_scan_state) {
 702                 case SCAN_DECISION:
 703                         /* if no more bands/channels left, complete scan */
 704                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 705                                 aborted = false;
 706                                 goto out_complete;
 707                         }
 708                         ieee80211_scan_state_decision(local, &next_delay);
 709                         break;
 710                 case SCAN_SET_CHANNEL:
 711                         ieee80211_scan_state_set_channel(local, &next_delay);
 712                         break;
 713                 case SCAN_SEND_PROBE:
 714                         ieee80211_scan_state_send_probe(local, &next_delay);
 715                         break;
 716                 case SCAN_LEAVE_OPER_CHANNEL:
 717                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
 718                         break;
 719                 case SCAN_ENTER_OPER_CHANNEL:
 720                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 721                         break;
 722                 }
 723         } while (next_delay == 0);
 724
 725         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 726         goto out;
 727
 728 out_complete:
 729         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 730         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 731 out:
 732         mutex_unlock(&local->mtx);
 733 }
 734
 735 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 736                            struct cfg80211_scan_request *req)
 737 {
 738         int res;
 739
 740         mutex_lock(&sdata->local->mtx);
 741         res = __ieee80211_start_scan(sdata, req);
 742         mutex_unlock(&sdata->local->mtx);
 743
 744         return res;
 745 }
 746
 747 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 748                                     const u8 *ssid, u8 ssid_len,
 749                                     struct ieee80211_channel *chan)
 750 {
 751         struct ieee80211_local *local = sdata->local;
 752         int ret = -EBUSY;
 753         enum ieee80211_band band;
 754
 755         mutex_lock(&local->mtx);
 756
 757         /* busy scanning */
 758         if (local->scan_req)
 759                 goto unlock;
 760
 761         /* fill internal scan request */
 762         if (!chan) {
 763                 int i, nchan = 0;
 764
 765                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 766                         if (!local->hw.wiphy->bands[band])
 767                                 continue;
 768                         for (i = 0;
 769                              i < local->hw.wiphy->bands[band]->n_channels;
 770                              i++) {
 771                                 local->int_scan_req->channels[nchan] =
 772                                     &local->hw.wiphy->bands[band]->channels[i];
 773                                 nchan++;
 774                         }
 775                 }
 776
 777                 local->int_scan_req->n_channels = nchan;
 778         } else {
 779                 local->int_scan_req->channels[0] = chan;
 780                 local->int_scan_req->n_channels = 1;
 781         }
 782
 783         local->int_scan_req->ssids = &local->scan_ssid;
 784         local->int_scan_req->n_ssids = 1;
 785         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 786         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 787
 788         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 789  unlock:
 790         mutex_unlock(&local->mtx);
 791         return ret;
 792 }
 793
 794 /*
 795  * Only call this function when a scan can't be queued -- under RTNL.
 796  */
 797 void ieee80211_scan_cancel(struct ieee80211_local *local)
 798 {
 799         /*
 800          * We are canceling software scan, or deferred scan that was not
 801          * yet really started (see __ieee80211_start_scan ).
 802          *
 803          * Regarding hardware scan:
 804          * - we can not call  __ieee80211_scan_completed() as when
 805          *   SCAN_HW_SCANNING bit is set this function change
 806          *   local->hw_scan_req to operate on 5G band, what race with
 807          *   driver which can use local->hw_scan_req
 808          *
 809          * - we can not cancel scan_work since driver can schedule it
 810          *   by ieee80211_scan_completed(..., true) to finish scan
 811          *
 812          * Hence we only call the cancel_hw_scan() callback, but the low-level
 813          * driver is still responsible for calling ieee80211_scan_completed()
 814          * after the scan was completed/aborted.
 815          */
 816
 817         mutex_lock(&local->mtx);
 818         if (!local->scan_req)
 819                 goto out;
 820
 821         /*
 822          * We have a scan running and the driver already reported completion,
 823          * but the worker hasn't run yet or is stuck on the mutex - mark it as
 824          * cancelled.
 825          */
 826         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
 827             test_bit(SCAN_COMPLETED, &local->scanning)) {
 828                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 829                 goto out;
 830         }
 831
 832         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 833                 /*
 834                  * Make sure that __ieee80211_scan_completed doesn't trigger a
 835                  * scan on another band.
 836                  */
 837                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 838                 if (local->ops->cancel_hw_scan)
 839                         drv_cancel_hw_scan(local, local->scan_sdata);
 840                 goto out;
 841         }
 842
 843         /*
 844          * If the work is currently running, it must be blocked on
 845          * the mutex, but we'll set scan_sdata = NULL and it'll
 846          * simply exit once it acquires the mutex.
 847          */
 848         cancel_delayed_work(&local->scan_work);
 849         /* and clean up */
 850         __ieee80211_scan_completed(&local->hw, true, false);
 851 out:
 852         mutex_unlock(&local->mtx);
 853 }
 854
 855 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 856                                        struct cfg80211_sched_scan_request *req)
 857 {
 858         struct ieee80211_local *local = sdata->local;
 859         int ret, i;
 860
 861         mutex_lock(&sdata->local->mtx);
 862
 863         if (local->sched_scanning) {
 864                 ret = -EBUSY;
 865                 goto out;
 866         }
 867
 868         if (!local->ops->sched_scan_start) {
 869                 ret = -ENOTSUPP;
 870                 goto out;
 871         }
 872
 873         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 874                 local->sched_scan_ies.ie[i] = kzalloc(2 +
 875                                                       IEEE80211_MAX_SSID_LEN +
 876                                                       local->scan_ies_len +
 877                                                       req->ie_len,
 878                                                       GFP_KERNEL);
 879                 if (!local->sched_scan_ies.ie[i]) {
 880                         ret = -ENOMEM;
 881                         goto out_free;
 882                 }
 883
 884                 local->sched_scan_ies.len[i] =
 885                         ieee80211_build_preq_ies(local,
 886                                                  local->sched_scan_ies.ie[i],
 887                                                  req->ie, req->ie_len, i,
 888                                                  (u32) -1, 0);
 889         }
 890
 891         ret = drv_sched_scan_start(local, sdata, req,
 892                                    &local->sched_scan_ies);
 893         if (ret == 0) {
 894                 local->sched_scanning = true;
 895                 goto out;
 896         }
 897
 898 out_free:
 899         while (i > 0)
 900                 kfree(local->sched_scan_ies.ie[--i]);
 901 out:
 902         mutex_unlock(&sdata->local->mtx);
 903         return ret;
 904 }
 905
 906 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 907 {
 908         struct ieee80211_local *local = sdata->local;
 909         int ret = 0, i;
 910
 911         mutex_lock(&sdata->local->mtx);
 912
 913         if (!local->ops->sched_scan_stop) {
 914                 ret = -ENOTSUPP;
 915                 goto out;
 916         }
 917
 918         if (local->sched_scanning) {
 919                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 920                         kfree(local->sched_scan_ies.ie[i]);
 921
 922                 drv_sched_scan_stop(local, sdata);
 923                 local->sched_scanning = false;
 924         }
 925 out:
 926         mutex_unlock(&sdata->local->mtx);
 927
 928         return ret;
 929 }
 930
 931 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 932 {
 933         struct ieee80211_local *local = hw_to_local(hw);
 934
 935         trace_api_sched_scan_results(local);
 936
 937         cfg80211_sched_scan_results(hw->wiphy);
 938 }
 939 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 940
 941 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 942 {
 943         struct ieee80211_local *local =
 944                 container_of(work, struct ieee80211_local,
 945                              sched_scan_stopped_work);
 946         int i;
 947
 948         mutex_lock(&local->mtx);
 949
 950         if (!local->sched_scanning) {
 951                 mutex_unlock(&local->mtx);
 952                 return;
 953         }
 954
 955         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 956                 kfree(local->sched_scan_ies.ie[i]);
 957
 958         local->sched_scanning = false;
 959
 960         mutex_unlock(&local->mtx);
 961
 962         cfg80211_sched_scan_stopped(local->hw.wiphy);
 963 }
 964
 965 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
 966 {
 967         struct ieee80211_local *local = hw_to_local(hw);
 968
 969         trace_api_sched_scan_stopped(local);
 970
 971         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
 972 }
 973 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);