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_params.h>
  18 #include <net/sch_generic.h>
  19 #include <linux/slab.h>
  20 #include <net/mac80211.h>
  21
  22 #include "ieee80211_i.h"
  23 #include "driver-ops.h"
  24 #include "mesh.h"
  25
  26 #define IEEE80211_PROBE_DELAY (HZ / 33)
  27 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  28 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
  29
  30 struct ieee80211_bss *
  31 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
  32                      u8 *ssid, u8 ssid_len)
  33 {
  34         struct cfg80211_bss *cbss;
  35
  36         cbss = cfg80211_get_bss(local->hw.wiphy,
  37                                 ieee80211_get_channel(local->hw.wiphy, freq),
  38                                 bssid, ssid, ssid_len, 0, 0);
  39         if (!cbss)
  40                 return NULL;
  41         return (void *)cbss->priv;
  42 }
  43
  44 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
  45 {
  46         struct ieee80211_bss *bss = (void *)cbss->priv;
  47
  48         kfree(bss_mesh_id(bss));
  49         kfree(bss_mesh_cfg(bss));
  50 }
  51
  52 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  53                           struct ieee80211_bss *bss)
  54 {
  55         if (!bss)
  56                 return;
  57         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
  58 }
  59
  60 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  61 {
  62         u8 qos_info;
  63
  64         if (elems->wmm_info && elems->wmm_info_len == 7
  65             && elems->wmm_info[5] == 1)
  66                 qos_info = elems->wmm_info[6];
  67         else if (elems->wmm_param && elems->wmm_param_len == 24
  68                  && elems->wmm_param[5] == 1)
  69                 qos_info = elems->wmm_param[6];
  70         else
  71                 /* no valid wmm information or parameter element found */
  72                 return false;
  73
  74         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  75 }
  76
  77 struct ieee80211_bss *
  78 ieee80211_bss_info_update(struct ieee80211_local *local,
  79                           struct ieee80211_rx_status *rx_status,
  80                           struct ieee80211_mgmt *mgmt,
  81                           size_t len,
  82                           struct ieee802_11_elems *elems,
  83                           struct ieee80211_channel *channel,
  84                           bool beacon)
  85 {
  86         struct cfg80211_bss *cbss;
  87         struct ieee80211_bss *bss;
  88         int clen, srlen;
  89         s32 signal = 0;
  90
  91         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  92                 signal = rx_status->signal * 100;
  93         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  94                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  95
  96         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  97                                          mgmt, len, signal, GFP_ATOMIC);
  98
  99         if (!cbss)
 100                 return NULL;
 101
 102         cbss->free_priv = ieee80211_rx_bss_free;
 103         bss = (void *)cbss->priv;
 104
 105         /* save the ERP value so that it is available at association time */
 106         if (elems->erp_info && elems->erp_info_len >= 1) {
 107                 bss->erp_value = elems->erp_info[0];
 108                 bss->has_erp_value = 1;
 109         }
 110
 111         if (elems->tim) {
 112                 struct ieee80211_tim_ie *tim_ie =
 113                         (struct ieee80211_tim_ie *)elems->tim;
 114                 bss->dtim_period = tim_ie->dtim_period;
 115         }
 116
 117         /* If the beacon had no TIM IE, or it was invalid, use 1 */
 118         if (beacon && !bss->dtim_period)
 119                 bss->dtim_period = 1;
 120
 121         /* replace old supported rates if we get new values */
 122         srlen = 0;
 123         if (elems->supp_rates) {
 124                 clen = IEEE80211_MAX_SUPP_RATES;
 125                 if (clen > elems->supp_rates_len)
 126                         clen = elems->supp_rates_len;
 127                 memcpy(bss->supp_rates, elems->supp_rates, clen);
 128                 srlen += clen;
 129         }
 130         if (elems->ext_supp_rates) {
 131                 clen = IEEE80211_MAX_SUPP_RATES - srlen;
 132                 if (clen > elems->ext_supp_rates_len)
 133                         clen = elems->ext_supp_rates_len;
 134                 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
 135                 srlen += clen;
 136         }
 137         if (srlen)
 138                 bss->supp_rates_len = srlen;
 139
 140         bss->wmm_used = elems->wmm_param || elems->wmm_info;
 141         bss->uapsd_supported = is_uapsd_supported(elems);
 142
 143         if (!beacon)
 144                 bss->last_probe_resp = jiffies;
 145
 146         return bss;
 147 }
 148
 149 ieee80211_rx_result
 150 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 151 {
 152         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 153         struct ieee80211_mgmt *mgmt;
 154         struct ieee80211_bss *bss;
 155         u8 *elements;
 156         struct ieee80211_channel *channel;
 157         size_t baselen;
 158         int freq;
 159         __le16 fc;
 160         bool presp, beacon = false;
 161         struct ieee802_11_elems elems;
 162
 163         if (skb->len < 2)
 164                 return RX_DROP_UNUSABLE;
 165
 166         mgmt = (struct ieee80211_mgmt *) skb->data;
 167         fc = mgmt->frame_control;
 168
 169         if (ieee80211_is_ctl(fc))
 170                 return RX_CONTINUE;
 171
 172         if (skb->len < 24)
 173                 return RX_CONTINUE;
 174
 175         presp = ieee80211_is_probe_resp(fc);
 176         if (presp) {
 177                 /* ignore ProbeResp to foreign address */
 178                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
 179                         return RX_DROP_MONITOR;
 180
 181                 presp = true;
 182                 elements = mgmt->u.probe_resp.variable;
 183                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 184         } else {
 185                 beacon = ieee80211_is_beacon(fc);
 186                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 187                 elements = mgmt->u.beacon.variable;
 188         }
 189
 190         if (!presp && !beacon)
 191                 return RX_CONTINUE;
 192
 193         if (baselen > skb->len)
 194                 return RX_DROP_MONITOR;
 195
 196         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 197
 198         if (elems.ds_params && elems.ds_params_len == 1)
 199                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
 200                                                       rx_status->band);
 201         else
 202                 freq = rx_status->freq;
 203
 204         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 205
 206         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 207                 return RX_DROP_MONITOR;
 208
 209         bss = ieee80211_bss_info_update(sdata->local, rx_status,
 210                                         mgmt, skb->len, &elems,
 211                                         channel, beacon);
 212         if (bss)
 213                 ieee80211_rx_bss_put(sdata->local, bss);
 214
 215         /* If we are on-operating-channel, and this packet is for the
 216          * current channel, pass the pkt on up the stack so that
 217          * the rest of the stack can make use of it.
 218          */
 219         if (ieee80211_cfg_on_oper_channel(sdata->local)
 220             && (channel == sdata->local->oper_channel))
 221                 return RX_CONTINUE;
 222
 223         dev_kfree_skb(skb);
 224         return RX_QUEUED;
 225 }
 226
 227 /* return false if no more work */
 228 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 229 {
 230         struct cfg80211_scan_request *req = local->scan_req;
 231         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 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                                          sdata->rc_rateidx_mask[band], 0);
 257         local->hw_scan_req->ie_len = ielen;
 258
 259         return true;
 260 }
 261
 262 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 263                                        bool was_hw_scan)
 264 {
 265         struct ieee80211_local *local = hw_to_local(hw);
 266         bool on_oper_chan;
 267         bool enable_beacons = false;
 268
 269         lockdep_assert_held(&local->mtx);
 270
 271         /*
 272          * It's ok to abort a not-yet-running scan (that
 273          * we have one at all will be verified by checking
 274          * local->scan_req next), but not to complete it
 275          * successfully.
 276          */
 277         if (WARN_ON(!local->scanning && !aborted))
 278                 aborted = true;
 279
 280         if (WARN_ON(!local->scan_req))
 281                 return;
 282
 283         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 284                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
 285                 if (rc == 0)
 286                         return;
 287         }
 288
 289         kfree(local->hw_scan_req);
 290         local->hw_scan_req = NULL;
 291
 292         if (local->scan_req != local->int_scan_req)
 293                 cfg80211_scan_done(local->scan_req, aborted);
 294         local->scan_req = NULL;
 295         local->scan_sdata = NULL;
 296
 297         local->scanning = 0;
 298         local->scan_channel = NULL;
 299
 300         on_oper_chan = ieee80211_cfg_on_oper_channel(local);
 301
 302         if (was_hw_scan || !on_oper_chan)
 303                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 304         else
 305                 /* Set power back to normal operating levels. */
 306                 ieee80211_hw_config(local, 0);
 307
 308         if (!was_hw_scan) {
 309                 bool on_oper_chan2;
 310                 ieee80211_configure_filter(local);
 311                 drv_sw_scan_complete(local);
 312                 on_oper_chan2 = ieee80211_cfg_on_oper_channel(local);
 313                 /* We should always be on-channel at this point. */
 314                 WARN_ON(!on_oper_chan2);
 315                 if (on_oper_chan2 && (on_oper_chan != on_oper_chan2))
 316                         enable_beacons = true;
 317
 318                 ieee80211_offchannel_return(local, enable_beacons, true);
 319         }
 320
 321         ieee80211_recalc_idle(local);
 322
 323         ieee80211_mlme_notify_scan_completed(local);
 324         ieee80211_ibss_notify_scan_completed(local);
 325         ieee80211_mesh_notify_scan_completed(local);
 326         ieee80211_queue_work(&local->hw, &local->work_work);
 327 }
 328
 329 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 330 {
 331         struct ieee80211_local *local = hw_to_local(hw);
 332
 333         trace_api_scan_completed(local, aborted);
 334
 335         set_bit(SCAN_COMPLETED, &local->scanning);
 336         if (aborted)
 337                 set_bit(SCAN_ABORTED, &local->scanning);
 338         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 339 }
 340 EXPORT_SYMBOL(ieee80211_scan_completed);
 341
 342 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 343 {
 344         /*
 345          * Hardware/driver doesn't support hw_scan, so use software
 346          * scanning instead. First send a nullfunc frame with power save
 347          * bit on so that AP will buffer the frames for us while we are not
 348          * listening, then send probe requests to each channel and wait for
 349          * the responses. After all channels are scanned, tune back to the
 350          * original channel and send a nullfunc frame with power save bit
 351          * off to trigger the AP to send us all the buffered frames.
 352          *
 353          * Note that while local->sw_scanning is true everything else but
 354          * nullfunc frames and probe requests will be dropped in
 355          * ieee80211_tx_h_check_assoc().
 356          */
 357         drv_sw_scan_start(local);
 358
 359         local->leave_oper_channel_time = 0;
 360         local->next_scan_state = SCAN_DECISION;
 361         local->scan_channel_idx = 0;
 362
 363         /* We always want to use off-channel PS, even if we
 364          * are not really leaving oper-channel.  Don't
 365          * tell the AP though, as long as we are on-channel.
 366          */
 367         ieee80211_offchannel_enable_all_ps(local, false);
 368
 369         ieee80211_configure_filter(local);
 370
 371         /* We need to set power level at maximum rate for scanning. */
 372         ieee80211_hw_config(local, 0);
 373
 374         ieee80211_queue_delayed_work(&local->hw,
 375                                      &local->scan_work,
 376                                      IEEE80211_CHANNEL_TIME);
 377
 378         return 0;
 379 }
 380
 381
 382 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 383                                   struct cfg80211_scan_request *req)
 384 {
 385         struct ieee80211_local *local = sdata->local;
 386         int rc;
 387
 388         lockdep_assert_held(&local->mtx);
 389
 390         if (local->scan_req)
 391                 return -EBUSY;
 392
 393         if (!list_empty(&local->work_list)) {
 394                 /* wait for the work to finish/time out */
 395                 local->scan_req = req;
 396                 local->scan_sdata = sdata;
 397                 return 0;
 398         }
 399
 400         if (local->ops->hw_scan) {
 401                 u8 *ies;
 402
 403                 local->hw_scan_req = kmalloc(
 404                                 sizeof(*local->hw_scan_req) +
 405                                 req->n_channels * sizeof(req->channels[0]) +
 406                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 407                                 req->ie_len, GFP_KERNEL);
 408                 if (!local->hw_scan_req)
 409                         return -ENOMEM;
 410
 411                 local->hw_scan_req->ssids = req->ssids;
 412                 local->hw_scan_req->n_ssids = req->n_ssids;
 413                 ies = (u8 *)local->hw_scan_req +
 414                         sizeof(*local->hw_scan_req) +
 415                         req->n_channels * sizeof(req->channels[0]);
 416                 local->hw_scan_req->ie = ies;
 417
 418                 local->hw_scan_band = 0;
 419
 420                 /*
 421                  * After allocating local->hw_scan_req, we must
 422                  * go through until ieee80211_prep_hw_scan(), so
 423                  * anything that might be changed here and leave
 424                  * this function early must not go after this
 425                  * allocation.
 426                  */
 427         }
 428
 429         local->scan_req = req;
 430         local->scan_sdata = sdata;
 431
 432         if (local->ops->hw_scan)
 433                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 434         else
 435                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 436
 437         ieee80211_recalc_idle(local);
 438
 439         if (local->ops->hw_scan) {
 440                 WARN_ON(!ieee80211_prep_hw_scan(local));
 441                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 442         } else
 443                 rc = ieee80211_start_sw_scan(local);
 444
 445         if (rc) {
 446                 kfree(local->hw_scan_req);
 447                 local->hw_scan_req = NULL;
 448                 local->scanning = 0;
 449
 450                 ieee80211_recalc_idle(local);
 451
 452                 local->scan_req = NULL;
 453                 local->scan_sdata = NULL;
 454         }
 455
 456         return rc;
 457 }
 458
 459 static unsigned long
 460 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 461 {
 462         /*
 463          * TODO: channel switching also consumes quite some time,
 464          * add that delay as well to get a better estimation
 465          */
 466         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 467                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 468         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 469 }
 470
 471 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 472                                           unsigned long *next_delay)
 473 {
 474         bool associated = false;
 475         bool tx_empty = true;
 476         bool bad_latency;
 477         bool listen_int_exceeded;
 478         unsigned long min_beacon_int = 0;
 479         struct ieee80211_sub_if_data *sdata;
 480         struct ieee80211_channel *next_chan;
 481
 482         /*
 483          * check if at least one STA interface is associated,
 484          * check if at least one STA interface has pending tx frames
 485          * and grab the lowest used beacon interval
 486          */
 487         mutex_lock(&local->iflist_mtx);
 488         list_for_each_entry(sdata, &local->interfaces, list) {
 489                 if (!ieee80211_sdata_running(sdata))
 490                         continue;
 491
 492                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 493                         if (sdata->u.mgd.associated) {
 494                                 associated = true;
 495
 496                                 if (sdata->vif.bss_conf.beacon_int <
 497                                     min_beacon_int || min_beacon_int == 0)
 498                                         min_beacon_int =
 499                                                 sdata->vif.bss_conf.beacon_int;
 500
 501                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 502                                         tx_empty = false;
 503                                         break;
 504                                 }
 505                         }
 506                 }
 507         }
 508         mutex_unlock(&local->iflist_mtx);
 509
 510         next_chan = local->scan_req->channels[local->scan_channel_idx];
 511
 512         if (ieee80211_cfg_on_oper_channel(local)) {
 513                 /* We're currently on operating channel. */
 514                 if (next_chan == local->oper_channel)
 515                         /* We don't need to move off of operating channel. */
 516                         local->next_scan_state = SCAN_SET_CHANNEL;
 517                 else
 518                         /*
 519                          * We do need to leave operating channel, as next
 520                          * scan is somewhere else.
 521                          */
 522                         local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
 523         } else {
 524                 /*
 525                  * we're currently scanning a different channel, let's
 526                  * see if we can scan another channel without interfering
 527                  * with the current traffic situation.
 528                  *
 529                  * Since we don't know if the AP has pending frames for us
 530                  * we can only check for our tx queues and use the current
 531                  * pm_qos requirements for rx. Hence, if no tx traffic occurs
 532                  * at all we will scan as many channels in a row as the pm_qos
 533                  * latency allows us to. Additionally we also check for the
 534                  * currently negotiated listen interval to prevent losing
 535                  * frames unnecessarily.
 536                  *
 537                  * Otherwise switch back to the operating channel.
 538                  */
 539
 540                 bad_latency = time_after(jiffies +
 541                                 ieee80211_scan_get_channel_time(next_chan),
 542                                 local->leave_oper_channel_time +
 543                                 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 544
 545                 listen_int_exceeded = time_after(jiffies +
 546                                 ieee80211_scan_get_channel_time(next_chan),
 547                                 local->leave_oper_channel_time +
 548                                 usecs_to_jiffies(min_beacon_int * 1024) *
 549                                 local->hw.conf.listen_interval);
 550
 551                 if (associated && ( !tx_empty || bad_latency ||
 552                     listen_int_exceeded))
 553                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
 554                 else
 555                         local->next_scan_state = SCAN_SET_CHANNEL;
 556         }
 557
 558         *next_delay = 0;
 559 }
 560
 561 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
 562                                                     unsigned long *next_delay)
 563 {
 564         /* PS will already be in off-channel mode,
 565          * we do that once at the beginning of scanning.
 566          */
 567         ieee80211_offchannel_stop_vifs(local, false);
 568
 569         /*
 570          * What if the nullfunc frames didn't arrive?
 571          */
 572         drv_flush(local, false);
 573         if (local->ops->flush)
 574                 *next_delay = 0;
 575         else
 576                 *next_delay = HZ / 10;
 577
 578         /* remember when we left the operating channel */
 579         local->leave_oper_channel_time = jiffies;
 580
 581         /* advance to the next channel to be scanned */
 582         local->next_scan_state = SCAN_SET_CHANNEL;
 583 }
 584
 585 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
 586                                                     unsigned long *next_delay)
 587 {
 588         /* switch back to the operating channel */
 589         local->scan_channel = NULL;
 590         if (!ieee80211_cfg_on_oper_channel(local))
 591                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 592
 593         /*
 594          * Re-enable vifs and beaconing.  Leave PS
 595          * in off-channel state..will put that back
 596          * on-channel at the end of scanning.
 597          */
 598         ieee80211_offchannel_return(local, true, false);
 599
 600         *next_delay = HZ / 5;
 601         local->next_scan_state = SCAN_DECISION;
 602 }
 603
 604 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 605                                              unsigned long *next_delay)
 606 {
 607         int skip;
 608         struct ieee80211_channel *chan;
 609
 610         skip = 0;
 611         chan = local->scan_req->channels[local->scan_channel_idx];
 612
 613         local->scan_channel = chan;
 614
 615         /* Only call hw-config if we really need to change channels. */
 616         if (chan != local->hw.conf.channel)
 617                 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 618                         skip = 1;
 619
 620         /* advance state machine to next channel/band */
 621         local->scan_channel_idx++;
 622
 623         if (skip) {
 624                 /* if we skip this channel return to the decision state */
 625                 local->next_scan_state = SCAN_DECISION;
 626                 return;
 627         }
 628
 629         /*
 630          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 631          * (which unfortunately doesn't say _why_ step a) is done,
 632          * but it waits for the probe delay or until a frame is
 633          * received - and the received frame would update the NAV).
 634          * For now, we do not support waiting until a frame is
 635          * received.
 636          *
 637          * In any case, it is not necessary for a passive scan.
 638          */
 639         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 640             !local->scan_req->n_ssids) {
 641                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 642                 local->next_scan_state = SCAN_DECISION;
 643                 return;
 644         }
 645
 646         /* active scan, send probes */
 647         *next_delay = IEEE80211_PROBE_DELAY;
 648         local->next_scan_state = SCAN_SEND_PROBE;
 649 }
 650
 651 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 652                                             unsigned long *next_delay)
 653 {
 654         int i;
 655         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 656
 657         for (i = 0; i < local->scan_req->n_ssids; i++)
 658                 ieee80211_send_probe_req(
 659                         sdata, NULL,
 660                         local->scan_req->ssids[i].ssid,
 661                         local->scan_req->ssids[i].ssid_len,
 662                         local->scan_req->ie, local->scan_req->ie_len,
 663                         false);
 664
 665         /*
 666          * After sending probe requests, wait for probe responses
 667          * on the channel.
 668          */
 669         *next_delay = IEEE80211_CHANNEL_TIME;
 670         local->next_scan_state = SCAN_DECISION;
 671 }
 672
 673 void ieee80211_scan_work(struct work_struct *work)
 674 {
 675         struct ieee80211_local *local =
 676                 container_of(work, struct ieee80211_local, scan_work.work);
 677         struct ieee80211_sub_if_data *sdata;
 678         unsigned long next_delay = 0;
 679         bool aborted, hw_scan;
 680
 681         mutex_lock(&local->mtx);
 682
 683         sdata = local->scan_sdata;
 684
 685         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 686                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 687                 goto out_complete;
 688         }
 689
 690         if (!sdata || !local->scan_req)
 691                 goto out;
 692
 693         if (local->scan_req && !local->scanning) {
 694                 struct cfg80211_scan_request *req = local->scan_req;
 695                 int rc;
 696
 697                 local->scan_req = NULL;
 698                 local->scan_sdata = NULL;
 699
 700                 rc = __ieee80211_start_scan(sdata, req);
 701                 if (rc) {
 702                         /* need to complete scan in cfg80211 */
 703                         local->scan_req = req;
 704                         aborted = true;
 705                         goto out_complete;
 706                 } else
 707                         goto out;
 708         }
 709
 710         /*
 711          * Avoid re-scheduling when the sdata is going away.
 712          */
 713         if (!ieee80211_sdata_running(sdata)) {
 714                 aborted = true;
 715                 goto out_complete;
 716         }
 717
 718         /*
 719          * as long as no delay is required advance immediately
 720          * without scheduling a new work
 721          */
 722         do {
 723                 if (!ieee80211_sdata_running(sdata)) {
 724                         aborted = true;
 725                         goto out_complete;
 726                 }
 727
 728                 switch (local->next_scan_state) {
 729                 case SCAN_DECISION:
 730                         /* if no more bands/channels left, complete scan */
 731                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 732                                 aborted = false;
 733                                 goto out_complete;
 734                         }
 735                         ieee80211_scan_state_decision(local, &next_delay);
 736                         break;
 737                 case SCAN_SET_CHANNEL:
 738                         ieee80211_scan_state_set_channel(local, &next_delay);
 739                         break;
 740                 case SCAN_SEND_PROBE:
 741                         ieee80211_scan_state_send_probe(local, &next_delay);
 742                         break;
 743                 case SCAN_LEAVE_OPER_CHANNEL:
 744                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
 745                         break;
 746                 case SCAN_ENTER_OPER_CHANNEL:
 747                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 748                         break;
 749                 }
 750         } while (next_delay == 0);
 751
 752         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 753         goto out;
 754
 755 out_complete:
 756         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 757         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 758 out:
 759         mutex_unlock(&local->mtx);
 760 }
 761
 762 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 763                            struct cfg80211_scan_request *req)
 764 {
 765         int res;
 766
 767         mutex_lock(&sdata->local->mtx);
 768         res = __ieee80211_start_scan(sdata, req);
 769         mutex_unlock(&sdata->local->mtx);
 770
 771         return res;
 772 }
 773
 774 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 775                                     const u8 *ssid, u8 ssid_len,
 776                                     struct ieee80211_channel *chan)
 777 {
 778         struct ieee80211_local *local = sdata->local;
 779         int ret = -EBUSY;
 780         enum ieee80211_band band;
 781
 782         mutex_lock(&local->mtx);
 783
 784         /* busy scanning */
 785         if (local->scan_req)
 786                 goto unlock;
 787
 788         /* fill internal scan request */
 789         if (!chan) {
 790                 int i, nchan = 0;
 791
 792                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 793                         if (!local->hw.wiphy->bands[band])
 794                                 continue;
 795                         for (i = 0;
 796                              i < local->hw.wiphy->bands[band]->n_channels;
 797                              i++) {
 798                                 local->int_scan_req->channels[nchan] =
 799                                     &local->hw.wiphy->bands[band]->channels[i];
 800                                 nchan++;
 801                         }
 802                 }
 803
 804                 local->int_scan_req->n_channels = nchan;
 805         } else {
 806                 local->int_scan_req->channels[0] = chan;
 807                 local->int_scan_req->n_channels = 1;
 808         }
 809
 810         local->int_scan_req->ssids = &local->scan_ssid;
 811         local->int_scan_req->n_ssids = 1;
 812         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 813         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 814
 815         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 816  unlock:
 817         mutex_unlock(&local->mtx);
 818         return ret;
 819 }
 820
 821 /*
 822  * Only call this function when a scan can't be queued -- under RTNL.
 823  */
 824 void ieee80211_scan_cancel(struct ieee80211_local *local)
 825 {
 826         /*
 827          * We are canceling software scan, or deferred scan that was not
 828          * yet really started (see __ieee80211_start_scan ).
 829          *
 830          * Regarding hardware scan:
 831          * - we can not call  __ieee80211_scan_completed() as when
 832          *   SCAN_HW_SCANNING bit is set this function change
 833          *   local->hw_scan_req to operate on 5G band, what race with
 834          *   driver which can use local->hw_scan_req
 835          *
 836          * - we can not cancel scan_work since driver can schedule it
 837          *   by ieee80211_scan_completed(..., true) to finish scan
 838          *
 839          * Hence we only call the cancel_hw_scan() callback, but the low-level
 840          * driver is still responsible for calling ieee80211_scan_completed()
 841          * after the scan was completed/aborted.
 842          */
 843
 844         mutex_lock(&local->mtx);
 845         if (!local->scan_req)
 846                 goto out;
 847
 848         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 849                 if (local->ops->cancel_hw_scan)
 850                         drv_cancel_hw_scan(local, local->scan_sdata);
 851                 goto out;
 852         }
 853
 854         /*
 855          * If the work is currently running, it must be blocked on
 856          * the mutex, but we'll set scan_sdata = NULL and it'll
 857          * simply exit once it acquires the mutex.
 858          */
 859         cancel_delayed_work(&local->scan_work);
 860         /* and clean up */
 861         __ieee80211_scan_completed(&local->hw, true, false);
 862 out:
 863         mutex_unlock(&local->mtx);
 864 }
 865
 866 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 867                                        struct cfg80211_sched_scan_request *req)
 868 {
 869         struct ieee80211_local *local = sdata->local;
 870         int ret, i;
 871
 872         mutex_lock(&sdata->local->mtx);
 873
 874         if (local->sched_scanning) {
 875                 ret = -EBUSY;
 876                 goto out;
 877         }
 878
 879         if (!local->ops->sched_scan_start) {
 880                 ret = -ENOTSUPP;
 881                 goto out;
 882         }
 883
 884         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 885                 local->sched_scan_ies.ie[i] = kzalloc(2 +
 886                                                       IEEE80211_MAX_SSID_LEN +
 887                                                       local->scan_ies_len +
 888                                                       req->ie_len,
 889                                                       GFP_KERNEL);
 890                 if (!local->sched_scan_ies.ie[i]) {
 891                         ret = -ENOMEM;
 892                         goto out_free;
 893                 }
 894
 895                 local->sched_scan_ies.len[i] =
 896                         ieee80211_build_preq_ies(local,
 897                                                  local->sched_scan_ies.ie[i],
 898                                                  req->ie, req->ie_len, i,
 899                                                  (u32) -1, 0);
 900         }
 901
 902         ret = drv_sched_scan_start(local, sdata, req,
 903                                    &local->sched_scan_ies);
 904         if (ret == 0) {
 905                 local->sched_scanning = true;
 906                 goto out;
 907         }
 908
 909 out_free:
 910         while (i > 0)
 911                 kfree(local->sched_scan_ies.ie[--i]);
 912 out:
 913         mutex_unlock(&sdata->local->mtx);
 914         return ret;
 915 }
 916
 917 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 918 {
 919         struct ieee80211_local *local = sdata->local;
 920         int ret = 0, i;
 921
 922         mutex_lock(&sdata->local->mtx);
 923
 924         if (!local->ops->sched_scan_stop) {
 925                 ret = -ENOTSUPP;
 926                 goto out;
 927         }
 928
 929         if (local->sched_scanning) {
 930                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 931                         kfree(local->sched_scan_ies.ie[i]);
 932
 933                 drv_sched_scan_stop(local, sdata);
 934                 local->sched_scanning = false;
 935         }
 936 out:
 937         mutex_unlock(&sdata->local->mtx);
 938
 939         return ret;
 940 }
 941
 942 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 943 {
 944         struct ieee80211_local *local = hw_to_local(hw);
 945
 946         trace_api_sched_scan_results(local);
 947
 948         cfg80211_sched_scan_results(hw->wiphy);
 949 }
 950 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 951
 952 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 953 {
 954         struct ieee80211_local *local =
 955                 container_of(work, struct ieee80211_local,
 956                              sched_scan_stopped_work);
 957         int i;
 958
 959         mutex_lock(&local->mtx);
 960
 961         if (!local->sched_scanning) {
 962                 mutex_unlock(&local->mtx);
 963                 return;
 964         }
 965
 966         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 967                 kfree(local->sched_scan_ies.ie[i]);
 968
 969         local->sched_scanning = false;
 970
 971         mutex_unlock(&local->mtx);
 972
 973         cfg80211_sched_scan_stopped(local->hw.wiphy);
 974 }
 975
 976 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
 977 {
 978         struct ieee80211_local *local = hw_to_local(hw);
 979
 980         trace_api_sched_scan_stopped(local);
 981
 982         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
 983 }
 984 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);