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 <linux/slab.h>
  19 #include <net/sch_generic.h>
  20 #include <linux/slab.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, (u32) -1,
 256                                          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
 664         /*
 665          * After sending probe requests, wait for probe responses
 666          * on the channel.
 667          */
 668         *next_delay = IEEE80211_CHANNEL_TIME;
 669         local->next_scan_state = SCAN_DECISION;
 670 }
 671
 672 void ieee80211_scan_work(struct work_struct *work)
 673 {
 674         struct ieee80211_local *local =
 675                 container_of(work, struct ieee80211_local, scan_work.work);
 676         struct ieee80211_sub_if_data *sdata;
 677         unsigned long next_delay = 0;
 678         bool aborted, hw_scan;
 679
 680         mutex_lock(&local->mtx);
 681
 682         sdata = local->scan_sdata;
 683
 684         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 685                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 686                 goto out_complete;
 687         }
 688
 689         if (!sdata || !local->scan_req)
 690                 goto out;
 691
 692         if (local->scan_req && !local->scanning) {
 693                 struct cfg80211_scan_request *req = local->scan_req;
 694                 int rc;
 695
 696                 local->scan_req = NULL;
 697                 local->scan_sdata = NULL;
 698
 699                 rc = __ieee80211_start_scan(sdata, req);
 700                 if (rc) {
 701                         /* need to complete scan in cfg80211 */
 702                         local->scan_req = req;
 703                         aborted = true;
 704                         goto out_complete;
 705                 } else
 706                         goto out;
 707         }
 708
 709         /*
 710          * Avoid re-scheduling when the sdata is going away.
 711          */
 712         if (!ieee80211_sdata_running(sdata)) {
 713                 aborted = true;
 714                 goto out_complete;
 715         }
 716
 717         /*
 718          * as long as no delay is required advance immediately
 719          * without scheduling a new work
 720          */
 721         do {
 722                 if (!ieee80211_sdata_running(sdata)) {
 723                         aborted = true;
 724                         goto out_complete;
 725                 }
 726
 727                 switch (local->next_scan_state) {
 728                 case SCAN_DECISION:
 729                         /* if no more bands/channels left, complete scan */
 730                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 731                                 aborted = false;
 732                                 goto out_complete;
 733                         }
 734                         ieee80211_scan_state_decision(local, &next_delay);
 735                         break;
 736                 case SCAN_SET_CHANNEL:
 737                         ieee80211_scan_state_set_channel(local, &next_delay);
 738                         break;
 739                 case SCAN_SEND_PROBE:
 740                         ieee80211_scan_state_send_probe(local, &next_delay);
 741                         break;
 742                 case SCAN_LEAVE_OPER_CHANNEL:
 743                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
 744                         break;
 745                 case SCAN_ENTER_OPER_CHANNEL:
 746                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 747                         break;
 748                 }
 749         } while (next_delay == 0);
 750
 751         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 752         goto out;
 753
 754 out_complete:
 755         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 756         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 757 out:
 758         mutex_unlock(&local->mtx);
 759 }
 760
 761 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 762                            struct cfg80211_scan_request *req)
 763 {
 764         int res;
 765
 766         mutex_lock(&sdata->local->mtx);
 767         res = __ieee80211_start_scan(sdata, req);
 768         mutex_unlock(&sdata->local->mtx);
 769
 770         return res;
 771 }
 772
 773 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 774                                     const u8 *ssid, u8 ssid_len,
 775                                     struct ieee80211_channel *chan)
 776 {
 777         struct ieee80211_local *local = sdata->local;
 778         int ret = -EBUSY;
 779         enum ieee80211_band band;
 780
 781         mutex_lock(&local->mtx);
 782
 783         /* busy scanning */
 784         if (local->scan_req)
 785                 goto unlock;
 786
 787         /* fill internal scan request */
 788         if (!chan) {
 789                 int i, nchan = 0;
 790
 791                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 792                         if (!local->hw.wiphy->bands[band])
 793                                 continue;
 794                         for (i = 0;
 795                              i < local->hw.wiphy->bands[band]->n_channels;
 796                              i++) {
 797                                 local->int_scan_req->channels[nchan] =
 798                                     &local->hw.wiphy->bands[band]->channels[i];
 799                                 nchan++;
 800                         }
 801                 }
 802
 803                 local->int_scan_req->n_channels = nchan;
 804         } else {
 805                 local->int_scan_req->channels[0] = chan;
 806                 local->int_scan_req->n_channels = 1;
 807         }
 808
 809         local->int_scan_req->ssids = &local->scan_ssid;
 810         local->int_scan_req->n_ssids = 1;
 811         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 812         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 813
 814         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 815  unlock:
 816         mutex_unlock(&local->mtx);
 817         return ret;
 818 }
 819
 820 /*
 821  * Only call this function when a scan can't be queued -- under RTNL.
 822  */
 823 void ieee80211_scan_cancel(struct ieee80211_local *local)
 824 {
 825         bool abortscan;
 826
 827         /*
 828          * We are only canceling software scan, or deferred scan that was not
 829          * yet really started (see __ieee80211_start_scan ).
 830          *
 831          * Regarding hardware scan:
 832          * - we can not call  __ieee80211_scan_completed() as when
 833          *   SCAN_HW_SCANNING bit is set this function change
 834          *   local->hw_scan_req to operate on 5G band, what race with
 835          *   driver which can use local->hw_scan_req
 836          *
 837          * - we can not cancel scan_work since driver can schedule it
 838          *   by ieee80211_scan_completed(..., true) to finish scan
 839          *
 840          * Hence low lever driver is responsible for canceling HW scan.
 841          */
 842
 843         mutex_lock(&local->mtx);
 844         abortscan = local->scan_req && !test_bit(SCAN_HW_SCANNING, &local->scanning);
 845         if (abortscan) {
 846                 /*
 847                  * The scan is canceled, but stop work from being pending.
 848                  *
 849                  * If the work is currently running, it must be blocked on
 850                  * the mutex, but we'll set scan_sdata = NULL and it'll
 851                  * simply exit once it acquires the mutex.
 852                  */
 853                 cancel_delayed_work(&local->scan_work);
 854                 /* and clean up */
 855                 __ieee80211_scan_completed(&local->hw, true, false);
 856         }
 857         mutex_unlock(&local->mtx);
 858 }
 859
 860 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 861                                        struct cfg80211_sched_scan_request *req)
 862 {
 863         struct ieee80211_local *local = sdata->local;
 864         int ret, i;
 865
 866         mutex_lock(&sdata->local->mtx);
 867
 868         if (local->sched_scanning) {
 869                 ret = -EBUSY;
 870                 goto out;
 871         }
 872
 873         if (!local->ops->sched_scan_start) {
 874                 ret = -ENOTSUPP;
 875                 goto out;
 876         }
 877
 878         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 879                 local->sched_scan_ies.ie[i] = kzalloc(2 +
 880                                                       IEEE80211_MAX_SSID_LEN +
 881                                                       local->scan_ies_len,
 882                                                       GFP_KERNEL);
 883                 if (!local->sched_scan_ies.ie[i]) {
 884                         ret = -ENOMEM;
 885                         goto out_free;
 886                 }
 887
 888                 local->sched_scan_ies.len[i] =
 889                         ieee80211_build_preq_ies(local,
 890                                                  local->sched_scan_ies.ie[i],
 891                                                  req->ie, req->ie_len, i,
 892                                                  (u32) -1, 0);
 893         }
 894
 895         ret = drv_sched_scan_start(local, sdata, req,
 896                                    &local->sched_scan_ies);
 897         if (ret == 0) {
 898                 local->sched_scanning = true;
 899                 goto out;
 900         }
 901
 902 out_free:
 903         while (i > 0)
 904                 kfree(local->sched_scan_ies.ie[--i]);
 905 out:
 906         mutex_unlock(&sdata->local->mtx);
 907         return ret;
 908 }
 909
 910 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 911 {
 912         struct ieee80211_local *local = sdata->local;
 913         int ret = 0, i;
 914
 915         mutex_lock(&sdata->local->mtx);
 916
 917         if (!local->ops->sched_scan_stop) {
 918                 ret = -ENOTSUPP;
 919                 goto out;
 920         }
 921
 922         if (local->sched_scanning) {
 923                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 924                         kfree(local->sched_scan_ies.ie[i]);
 925
 926                 drv_sched_scan_stop(local, sdata);
 927                 local->sched_scanning = false;
 928         }
 929 out:
 930         mutex_unlock(&sdata->local->mtx);
 931
 932         return ret;
 933 }
 934
 935 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 936 {
 937         struct ieee80211_local *local = hw_to_local(hw);
 938
 939         trace_api_sched_scan_results(local);
 940
 941         cfg80211_sched_scan_results(hw->wiphy);
 942 }
 943 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 944
 945 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 946 {
 947         struct ieee80211_local *local =
 948                 container_of(work, struct ieee80211_local,
 949                              sched_scan_stopped_work);
 950         int i;
 951
 952         mutex_lock(&local->mtx);
 953
 954         if (!local->sched_scanning) {
 955                 mutex_unlock(&local->mtx);
 956                 return;
 957         }
 958
 959         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 960                 kfree(local->sched_scan_ies.ie[i]);
 961
 962         local->sched_scanning = false;
 963
 964         mutex_unlock(&local->mtx);
 965
 966         cfg80211_sched_scan_stopped(local->hw.wiphy);
 967 }
 968
 969 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
 970 {
 971         struct ieee80211_local *local = hw_to_local(hw);
 972
 973         trace_api_sched_scan_stopped(local);
 974
 975         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
 976 }
 977 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);