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 we are on-operating-channel, and this packet is for the
 217          * current channel, pass the pkt on up the stack so that
 218          * the rest of the stack can make use of it.
 219          */
 220         if (ieee80211_cfg_on_oper_channel(sdata->local)
 221             && (channel == sdata->local->oper_channel))
 222                 return RX_CONTINUE;
 223
 224         dev_kfree_skb(skb);
 225         return RX_QUEUED;
 226 }
 227
 228 /* return false if no more work */
 229 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 230 {
 231         struct cfg80211_scan_request *req = local->scan_req;
 232         enum ieee80211_band band;
 233         int i, ielen, n_chans;
 234
 235         do {
 236                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 237                         return false;
 238
 239                 band = local->hw_scan_band;
 240                 n_chans = 0;
 241                 for (i = 0; i < req->n_channels; i++) {
 242                         if (req->channels[i]->band == band) {
 243                                 local->hw_scan_req->channels[n_chans] =
 244                                                         req->channels[i];
 245                                 n_chans++;
 246                         }
 247                 }
 248
 249                 local->hw_scan_band++;
 250         } while (!n_chans);
 251
 252         local->hw_scan_req->n_channels = n_chans;
 253
 254         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 255                                          req->ie, req->ie_len, band,
 256                                          req->rates[band], 0);
 257         local->hw_scan_req->ie_len = ielen;
 258         local->hw_scan_req->no_cck = req->no_cck;
 259
 260         return true;
 261 }
 262
 263 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 264                                        bool was_hw_scan)
 265 {
 266         struct ieee80211_local *local = hw_to_local(hw);
 267         bool on_oper_chan;
 268         bool enable_beacons = false;
 269
 270         lockdep_assert_held(&local->mtx);
 271
 272         /*
 273          * It's ok to abort a not-yet-running scan (that
 274          * we have one at all will be verified by checking
 275          * local->scan_req next), but not to complete it
 276          * successfully.
 277          */
 278         if (WARN_ON(!local->scanning && !aborted))
 279                 aborted = true;
 280
 281         if (WARN_ON(!local->scan_req))
 282                 return;
 283
 284         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 285                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
 286                 if (rc == 0)
 287                         return;
 288         }
 289
 290         kfree(local->hw_scan_req);
 291         local->hw_scan_req = NULL;
 292
 293         if (local->scan_req != local->int_scan_req)
 294                 cfg80211_scan_done(local->scan_req, aborted);
 295         local->scan_req = NULL;
 296         local->scan_sdata = NULL;
 297
 298         local->scanning = 0;
 299         local->scan_channel = NULL;
 300
 301         on_oper_chan = ieee80211_cfg_on_oper_channel(local);
 302
 303         if (was_hw_scan || !on_oper_chan)
 304                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 305         else
 306                 /* Set power back to normal operating levels. */
 307                 ieee80211_hw_config(local, 0);
 308
 309         if (!was_hw_scan) {
 310                 bool on_oper_chan2;
 311                 ieee80211_configure_filter(local);
 312                 drv_sw_scan_complete(local);
 313                 on_oper_chan2 = ieee80211_cfg_on_oper_channel(local);
 314                 /* We should always be on-channel at this point. */
 315                 WARN_ON(!on_oper_chan2);
 316                 if (on_oper_chan2 && (on_oper_chan != on_oper_chan2))
 317                         enable_beacons = true;
 318
 319                 ieee80211_offchannel_return(local, enable_beacons, true);
 320         }
 321
 322         ieee80211_recalc_idle(local);
 323
 324         ieee80211_mlme_notify_scan_completed(local);
 325         ieee80211_ibss_notify_scan_completed(local);
 326         ieee80211_mesh_notify_scan_completed(local);
 327         ieee80211_queue_work(&local->hw, &local->work_work);
 328 }
 329
 330 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 331 {
 332         struct ieee80211_local *local = hw_to_local(hw);
 333
 334         trace_api_scan_completed(local, aborted);
 335
 336         set_bit(SCAN_COMPLETED, &local->scanning);
 337         if (aborted)
 338                 set_bit(SCAN_ABORTED, &local->scanning);
 339         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 340 }
 341 EXPORT_SYMBOL(ieee80211_scan_completed);
 342
 343 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 344 {
 345         /*
 346          * Hardware/driver doesn't support hw_scan, so use software
 347          * scanning instead. First send a nullfunc frame with power save
 348          * bit on so that AP will buffer the frames for us while we are not
 349          * listening, then send probe requests to each channel and wait for
 350          * the responses. After all channels are scanned, tune back to the
 351          * original channel and send a nullfunc frame with power save bit
 352          * off to trigger the AP to send us all the buffered frames.
 353          *
 354          * Note that while local->sw_scanning is true everything else but
 355          * nullfunc frames and probe requests will be dropped in
 356          * ieee80211_tx_h_check_assoc().
 357          */
 358         drv_sw_scan_start(local);
 359
 360         local->leave_oper_channel_time = 0;
 361         local->next_scan_state = SCAN_DECISION;
 362         local->scan_channel_idx = 0;
 363
 364         /* We always want to use off-channel PS, even if we
 365          * are not really leaving oper-channel.  Don't
 366          * tell the AP though, as long as we are on-channel.
 367          */
 368         ieee80211_offchannel_enable_all_ps(local, false);
 369
 370         ieee80211_configure_filter(local);
 371
 372         /* We need to set power level at maximum rate for scanning. */
 373         ieee80211_hw_config(local, 0);
 374
 375         ieee80211_queue_delayed_work(&local->hw,
 376                                      &local->scan_work,
 377                                      IEEE80211_CHANNEL_TIME);
 378
 379         return 0;
 380 }
 381
 382
 383 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 384                                   struct cfg80211_scan_request *req)
 385 {
 386         struct ieee80211_local *local = sdata->local;
 387         int rc;
 388
 389         lockdep_assert_held(&local->mtx);
 390
 391         if (local->scan_req)
 392                 return -EBUSY;
 393
 394         if (!list_empty(&local->work_list)) {
 395                 /* wait for the work to finish/time out */
 396                 local->scan_req = req;
 397                 local->scan_sdata = sdata;
 398                 return 0;
 399         }
 400
 401         if (local->ops->hw_scan) {
 402                 u8 *ies;
 403
 404                 local->hw_scan_req = kmalloc(
 405                                 sizeof(*local->hw_scan_req) +
 406                                 req->n_channels * sizeof(req->channels[0]) +
 407                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 408                                 req->ie_len, GFP_KERNEL);
 409                 if (!local->hw_scan_req)
 410                         return -ENOMEM;
 411
 412                 local->hw_scan_req->ssids = req->ssids;
 413                 local->hw_scan_req->n_ssids = req->n_ssids;
 414                 ies = (u8 *)local->hw_scan_req +
 415                         sizeof(*local->hw_scan_req) +
 416                         req->n_channels * sizeof(req->channels[0]);
 417                 local->hw_scan_req->ie = ies;
 418
 419                 local->hw_scan_band = 0;
 420
 421                 /*
 422                  * After allocating local->hw_scan_req, we must
 423                  * go through until ieee80211_prep_hw_scan(), so
 424                  * anything that might be changed here and leave
 425                  * this function early must not go after this
 426                  * allocation.
 427                  */
 428         }
 429
 430         local->scan_req = req;
 431         local->scan_sdata = sdata;
 432
 433         if (local->ops->hw_scan)
 434                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 435         else
 436                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 437
 438         ieee80211_recalc_idle(local);
 439
 440         if (local->ops->hw_scan) {
 441                 WARN_ON(!ieee80211_prep_hw_scan(local));
 442                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 443         } else
 444                 rc = ieee80211_start_sw_scan(local);
 445
 446         if (rc) {
 447                 kfree(local->hw_scan_req);
 448                 local->hw_scan_req = NULL;
 449                 local->scanning = 0;
 450
 451                 ieee80211_recalc_idle(local);
 452
 453                 local->scan_req = NULL;
 454                 local->scan_sdata = NULL;
 455         }
 456
 457         return rc;
 458 }
 459
 460 static unsigned long
 461 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 462 {
 463         /*
 464          * TODO: channel switching also consumes quite some time,
 465          * add that delay as well to get a better estimation
 466          */
 467         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 468                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 469         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 470 }
 471
 472 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 473                                           unsigned long *next_delay)
 474 {
 475         bool associated = false;
 476         bool tx_empty = true;
 477         bool bad_latency;
 478         bool listen_int_exceeded;
 479         unsigned long min_beacon_int = 0;
 480         struct ieee80211_sub_if_data *sdata;
 481         struct ieee80211_channel *next_chan;
 482
 483         /*
 484          * check if at least one STA interface is associated,
 485          * check if at least one STA interface has pending tx frames
 486          * and grab the lowest used beacon interval
 487          */
 488         mutex_lock(&local->iflist_mtx);
 489         list_for_each_entry(sdata, &local->interfaces, list) {
 490                 if (!ieee80211_sdata_running(sdata))
 491                         continue;
 492
 493                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 494                         if (sdata->u.mgd.associated) {
 495                                 associated = true;
 496
 497                                 if (sdata->vif.bss_conf.beacon_int <
 498                                     min_beacon_int || min_beacon_int == 0)
 499                                         min_beacon_int =
 500                                                 sdata->vif.bss_conf.beacon_int;
 501
 502                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 503                                         tx_empty = false;
 504                                         break;
 505                                 }
 506                         }
 507                 }
 508         }
 509         mutex_unlock(&local->iflist_mtx);
 510
 511         next_chan = local->scan_req->channels[local->scan_channel_idx];
 512
 513         if (ieee80211_cfg_on_oper_channel(local)) {
 514                 /* We're currently on operating channel. */
 515                 if (next_chan == local->oper_channel)
 516                         /* We don't need to move off of operating channel. */
 517                         local->next_scan_state = SCAN_SET_CHANNEL;
 518                 else
 519                         /*
 520                          * We do need to leave operating channel, as next
 521                          * scan is somewhere else.
 522                          */
 523                         local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
 524         } else {
 525                 /*
 526                  * we're currently scanning a different channel, let's
 527                  * see if we can scan another channel without interfering
 528                  * with the current traffic situation.
 529                  *
 530                  * Since we don't know if the AP has pending frames for us
 531                  * we can only check for our tx queues and use the current
 532                  * pm_qos requirements for rx. Hence, if no tx traffic occurs
 533                  * at all we will scan as many channels in a row as the pm_qos
 534                  * latency allows us to. Additionally we also check for the
 535                  * currently negotiated listen interval to prevent losing
 536                  * frames unnecessarily.
 537                  *
 538                  * Otherwise switch back to the operating channel.
 539                  */
 540
 541                 bad_latency = time_after(jiffies +
 542                                 ieee80211_scan_get_channel_time(next_chan),
 543                                 local->leave_oper_channel_time +
 544                                 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 545
 546                 listen_int_exceeded = time_after(jiffies +
 547                                 ieee80211_scan_get_channel_time(next_chan),
 548                                 local->leave_oper_channel_time +
 549                                 usecs_to_jiffies(min_beacon_int * 1024) *
 550                                 local->hw.conf.listen_interval);
 551
 552                 if (associated && ( !tx_empty || bad_latency ||
 553                     listen_int_exceeded))
 554                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
 555                 else
 556                         local->next_scan_state = SCAN_SET_CHANNEL;
 557         }
 558
 559         *next_delay = 0;
 560 }
 561
 562 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
 563                                                     unsigned long *next_delay)
 564 {
 565         /* PS will already be in off-channel mode,
 566          * we do that once at the beginning of scanning.
 567          */
 568         ieee80211_offchannel_stop_vifs(local, false);
 569
 570         /*
 571          * What if the nullfunc frames didn't arrive?
 572          */
 573         drv_flush(local, false);
 574         if (local->ops->flush)
 575                 *next_delay = 0;
 576         else
 577                 *next_delay = HZ / 10;
 578
 579         /* remember when we left the operating channel */
 580         local->leave_oper_channel_time = jiffies;
 581
 582         /* advance to the next channel to be scanned */
 583         local->next_scan_state = SCAN_SET_CHANNEL;
 584 }
 585
 586 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
 587                                                     unsigned long *next_delay)
 588 {
 589         /* switch back to the operating channel */
 590         local->scan_channel = NULL;
 591         if (!ieee80211_cfg_on_oper_channel(local))
 592                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 593
 594         /*
 595          * Re-enable vifs and beaconing.  Leave PS
 596          * in off-channel state..will put that back
 597          * on-channel at the end of scanning.
 598          */
 599         ieee80211_offchannel_return(local, true, false);
 600
 601         *next_delay = HZ / 5;
 602         local->next_scan_state = SCAN_DECISION;
 603 }
 604
 605 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 606                                              unsigned long *next_delay)
 607 {
 608         int skip;
 609         struct ieee80211_channel *chan;
 610
 611         skip = 0;
 612         chan = local->scan_req->channels[local->scan_channel_idx];
 613
 614         local->scan_channel = chan;
 615
 616         /* Only call hw-config if we really need to change channels. */
 617         if (chan != local->hw.conf.channel)
 618                 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 619                         skip = 1;
 620
 621         /* advance state machine to next channel/band */
 622         local->scan_channel_idx++;
 623
 624         if (skip) {
 625                 /* if we skip this channel return to the decision state */
 626                 local->next_scan_state = SCAN_DECISION;
 627                 return;
 628         }
 629
 630         /*
 631          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 632          * (which unfortunately doesn't say _why_ step a) is done,
 633          * but it waits for the probe delay or until a frame is
 634          * received - and the received frame would update the NAV).
 635          * For now, we do not support waiting until a frame is
 636          * received.
 637          *
 638          * In any case, it is not necessary for a passive scan.
 639          */
 640         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 641             !local->scan_req->n_ssids) {
 642                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 643                 local->next_scan_state = SCAN_DECISION;
 644                 return;
 645         }
 646
 647         /* active scan, send probes */
 648         *next_delay = IEEE80211_PROBE_DELAY;
 649         local->next_scan_state = SCAN_SEND_PROBE;
 650 }
 651
 652 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 653                                             unsigned long *next_delay)
 654 {
 655         int i;
 656         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 657         enum ieee80211_band band = local->hw.conf.channel->band;
 658
 659         for (i = 0; i < local->scan_req->n_ssids; i++)
 660                 ieee80211_send_probe_req(
 661                         sdata, NULL,
 662                         local->scan_req->ssids[i].ssid,
 663                         local->scan_req->ssids[i].ssid_len,
 664                         local->scan_req->ie, local->scan_req->ie_len,
 665                         local->scan_req->rates[band], false,
 666                         local->scan_req->no_cck);
 667
 668         /*
 669          * After sending probe requests, wait for probe responses
 670          * on the channel.
 671          */
 672         *next_delay = IEEE80211_CHANNEL_TIME;
 673         local->next_scan_state = SCAN_DECISION;
 674 }
 675
 676 void ieee80211_scan_work(struct work_struct *work)
 677 {
 678         struct ieee80211_local *local =
 679                 container_of(work, struct ieee80211_local, scan_work.work);
 680         struct ieee80211_sub_if_data *sdata;
 681         unsigned long next_delay = 0;
 682         bool aborted, hw_scan;
 683
 684         mutex_lock(&local->mtx);
 685
 686         sdata = local->scan_sdata;
 687
 688         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 689                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 690                 goto out_complete;
 691         }
 692
 693         if (!sdata || !local->scan_req)
 694                 goto out;
 695
 696         if (local->scan_req && !local->scanning) {
 697                 struct cfg80211_scan_request *req = local->scan_req;
 698                 int rc;
 699
 700                 local->scan_req = NULL;
 701                 local->scan_sdata = NULL;
 702
 703                 rc = __ieee80211_start_scan(sdata, req);
 704                 if (rc) {
 705                         /* need to complete scan in cfg80211 */
 706                         local->scan_req = req;
 707                         aborted = true;
 708                         goto out_complete;
 709                 } else
 710                         goto out;
 711         }
 712
 713         /*
 714          * Avoid re-scheduling when the sdata is going away.
 715          */
 716         if (!ieee80211_sdata_running(sdata)) {
 717                 aborted = true;
 718                 goto out_complete;
 719         }
 720
 721         /*
 722          * as long as no delay is required advance immediately
 723          * without scheduling a new work
 724          */
 725         do {
 726                 if (!ieee80211_sdata_running(sdata)) {
 727                         aborted = true;
 728                         goto out_complete;
 729                 }
 730
 731                 switch (local->next_scan_state) {
 732                 case SCAN_DECISION:
 733                         /* if no more bands/channels left, complete scan */
 734                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 735                                 aborted = false;
 736                                 goto out_complete;
 737                         }
 738                         ieee80211_scan_state_decision(local, &next_delay);
 739                         break;
 740                 case SCAN_SET_CHANNEL:
 741                         ieee80211_scan_state_set_channel(local, &next_delay);
 742                         break;
 743                 case SCAN_SEND_PROBE:
 744                         ieee80211_scan_state_send_probe(local, &next_delay);
 745                         break;
 746                 case SCAN_LEAVE_OPER_CHANNEL:
 747                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
 748                         break;
 749                 case SCAN_ENTER_OPER_CHANNEL:
 750                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 751                         break;
 752                 }
 753         } while (next_delay == 0);
 754
 755         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 756         goto out;
 757
 758 out_complete:
 759         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 760         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 761 out:
 762         mutex_unlock(&local->mtx);
 763 }
 764
 765 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 766                            struct cfg80211_scan_request *req)
 767 {
 768         int res;
 769
 770         mutex_lock(&sdata->local->mtx);
 771         res = __ieee80211_start_scan(sdata, req);
 772         mutex_unlock(&sdata->local->mtx);
 773
 774         return res;
 775 }
 776
 777 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 778                                     const u8 *ssid, u8 ssid_len,
 779                                     struct ieee80211_channel *chan)
 780 {
 781         struct ieee80211_local *local = sdata->local;
 782         int ret = -EBUSY;
 783         enum ieee80211_band band;
 784
 785         mutex_lock(&local->mtx);
 786
 787         /* busy scanning */
 788         if (local->scan_req)
 789                 goto unlock;
 790
 791         /* fill internal scan request */
 792         if (!chan) {
 793                 int i, nchan = 0;
 794
 795                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 796                         if (!local->hw.wiphy->bands[band])
 797                                 continue;
 798                         for (i = 0;
 799                              i < local->hw.wiphy->bands[band]->n_channels;
 800                              i++) {
 801                                 local->int_scan_req->channels[nchan] =
 802                                     &local->hw.wiphy->bands[band]->channels[i];
 803                                 nchan++;
 804                         }
 805                 }
 806
 807                 local->int_scan_req->n_channels = nchan;
 808         } else {
 809                 local->int_scan_req->channels[0] = chan;
 810                 local->int_scan_req->n_channels = 1;
 811         }
 812
 813         local->int_scan_req->ssids = &local->scan_ssid;
 814         local->int_scan_req->n_ssids = 1;
 815         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 816         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 817
 818         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 819  unlock:
 820         mutex_unlock(&local->mtx);
 821         return ret;
 822 }
 823
 824 /*
 825  * Only call this function when a scan can't be queued -- under RTNL.
 826  */
 827 void ieee80211_scan_cancel(struct ieee80211_local *local)
 828 {
 829         /*
 830          * We are canceling software scan, or deferred scan that was not
 831          * yet really started (see __ieee80211_start_scan ).
 832          *
 833          * Regarding hardware scan:
 834          * - we can not call  __ieee80211_scan_completed() as when
 835          *   SCAN_HW_SCANNING bit is set this function change
 836          *   local->hw_scan_req to operate on 5G band, what race with
 837          *   driver which can use local->hw_scan_req
 838          *
 839          * - we can not cancel scan_work since driver can schedule it
 840          *   by ieee80211_scan_completed(..., true) to finish scan
 841          *
 842          * Hence we only call the cancel_hw_scan() callback, but the low-level
 843          * driver is still responsible for calling ieee80211_scan_completed()
 844          * after the scan was completed/aborted.
 845          */
 846
 847         mutex_lock(&local->mtx);
 848         if (!local->scan_req)
 849                 goto out;
 850
 851         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 852                 if (local->ops->cancel_hw_scan)
 853                         drv_cancel_hw_scan(local, local->scan_sdata);
 854                 goto out;
 855         }
 856
 857         /*
 858          * If the work is currently running, it must be blocked on
 859          * the mutex, but we'll set scan_sdata = NULL and it'll
 860          * simply exit once it acquires the mutex.
 861          */
 862         cancel_delayed_work(&local->scan_work);
 863         /* and clean up */
 864         __ieee80211_scan_completed(&local->hw, true, false);
 865 out:
 866         mutex_unlock(&local->mtx);
 867 }
 868
 869 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 870                                        struct cfg80211_sched_scan_request *req)
 871 {
 872         struct ieee80211_local *local = sdata->local;
 873         int ret, i;
 874
 875         mutex_lock(&sdata->local->mtx);
 876
 877         if (local->sched_scanning) {
 878                 ret = -EBUSY;
 879                 goto out;
 880         }
 881
 882         if (!local->ops->sched_scan_start) {
 883                 ret = -ENOTSUPP;
 884                 goto out;
 885         }
 886
 887         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 888                 local->sched_scan_ies.ie[i] = kzalloc(2 +
 889                                                       IEEE80211_MAX_SSID_LEN +
 890                                                       local->scan_ies_len +
 891                                                       req->ie_len,
 892                                                       GFP_KERNEL);
 893                 if (!local->sched_scan_ies.ie[i]) {
 894                         ret = -ENOMEM;
 895                         goto out_free;
 896                 }
 897
 898                 local->sched_scan_ies.len[i] =
 899                         ieee80211_build_preq_ies(local,
 900                                                  local->sched_scan_ies.ie[i],
 901                                                  req->ie, req->ie_len, i,
 902                                                  (u32) -1, 0);
 903         }
 904
 905         ret = drv_sched_scan_start(local, sdata, req,
 906                                    &local->sched_scan_ies);
 907         if (ret == 0) {
 908                 local->sched_scanning = true;
 909                 goto out;
 910         }
 911
 912 out_free:
 913         while (i > 0)
 914                 kfree(local->sched_scan_ies.ie[--i]);
 915 out:
 916         mutex_unlock(&sdata->local->mtx);
 917         return ret;
 918 }
 919
 920 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 921 {
 922         struct ieee80211_local *local = sdata->local;
 923         int ret = 0, i;
 924
 925         mutex_lock(&sdata->local->mtx);
 926
 927         if (!local->ops->sched_scan_stop) {
 928                 ret = -ENOTSUPP;
 929                 goto out;
 930         }
 931
 932         if (local->sched_scanning) {
 933                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 934                         kfree(local->sched_scan_ies.ie[i]);
 935
 936                 drv_sched_scan_stop(local, sdata);
 937                 local->sched_scanning = false;
 938         }
 939 out:
 940         mutex_unlock(&sdata->local->mtx);
 941
 942         return ret;
 943 }
 944
 945 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 946 {
 947         struct ieee80211_local *local = hw_to_local(hw);
 948
 949         trace_api_sched_scan_results(local);
 950
 951         cfg80211_sched_scan_results(hw->wiphy);
 952 }
 953 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 954
 955 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 956 {
 957         struct ieee80211_local *local =
 958                 container_of(work, struct ieee80211_local,
 959                              sched_scan_stopped_work);
 960         int i;
 961
 962         mutex_lock(&local->mtx);
 963
 964         if (!local->sched_scanning) {
 965                 mutex_unlock(&local->mtx);
 966                 return;
 967         }
 968
 969         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 970                 kfree(local->sched_scan_ies.ie[i]);
 971
 972         local->sched_scanning = false;
 973
 974         mutex_unlock(&local->mtx);
 975
 976         cfg80211_sched_scan_stopped(local->hw.wiphy);
 977 }
 978
 979 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
 980 {
 981         struct ieee80211_local *local = hw_to_local(hw);
 982
 983         trace_api_sched_scan_stopped(local);
 984
 985         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
 986 }
 987 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);