Pileus Git - ~andy/linux/blob - 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/etherdevice.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/pm_qos.h>
  19 #include <net/sch_generic.h>
  20 #include <linux/slab.h>
  21 #include <linux/export.h>
  22 #include <net/mac80211.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "mesh.h"
  27
  28 #define IEEE80211_PROBE_DELAY (HZ / 33)
  29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
  31
  32 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
  33 {
  34         struct ieee80211_bss *bss = (void *)cbss->priv;
  35
  36         kfree(bss_mesh_id(bss));
  37         kfree(bss_mesh_cfg(bss));
  38 }
  39
  40 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  41                           struct ieee80211_bss *bss)
  42 {
  43         if (!bss)
  44                 return;
  45         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
  46 }
  47
  48 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  49 {
  50         u8 qos_info;
  51
  52         if (elems->wmm_info && elems->wmm_info_len == 7
  53             && elems->wmm_info[5] == 1)
  54                 qos_info = elems->wmm_info[6];
  55         else if (elems->wmm_param && elems->wmm_param_len == 24
  56                  && elems->wmm_param[5] == 1)
  57                 qos_info = elems->wmm_param[6];
  58         else
  59                 /* no valid wmm information or parameter element found */
  60                 return false;
  61
  62         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  63 }
  64
  65 struct ieee80211_bss *
  66 ieee80211_bss_info_update(struct ieee80211_local *local,
  67                           struct ieee80211_rx_status *rx_status,
  68                           struct ieee80211_mgmt *mgmt,
  69                           size_t len,
  70                           struct ieee802_11_elems *elems,
  71                           struct ieee80211_channel *channel,
  72                           bool beacon)
  73 {
  74         struct cfg80211_bss *cbss;
  75         struct ieee80211_bss *bss;
  76         int clen, srlen;
  77         s32 signal = 0;
  78
  79         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  80                 signal = rx_status->signal * 100;
  81         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  82                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  83
  84         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  85                                          mgmt, len, signal, GFP_ATOMIC);
  86
  87         if (!cbss)
  88                 return NULL;
  89
  90         cbss->free_priv = ieee80211_rx_bss_free;
  91         bss = (void *)cbss->priv;
  92
  93         if (elems->parse_error) {
  94                 if (beacon)
  95                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  96                 else
  97                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  98         } else {
  99                 if (beacon)
 100                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 101                 else
 102                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 103         }
 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                         (!elems->parse_error ||
 108                          !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 109                 bss->erp_value = elems->erp_info[0];
 110                 bss->has_erp_value = true;
 111                 if (!elems->parse_error)
 112                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 113         }
 114
 115         if (elems->tim && (!elems->parse_error ||
 116                            !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) {
 117                 struct ieee80211_tim_ie *tim_ie =
 118                         (struct ieee80211_tim_ie *)elems->tim;
 119                 bss->dtim_period = tim_ie->dtim_period;
 120                 if (!elems->parse_error)
 121                                 bss->valid_data |= IEEE80211_BSS_VALID_DTIM;
 122         }
 123
 124         /* If the beacon had no TIM IE, or it was invalid, use 1 */
 125         if (beacon && !bss->dtim_period)
 126                 bss->dtim_period = 1;
 127
 128         /* replace old supported rates if we get new values */
 129         if (!elems->parse_error ||
 130             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 131                 srlen = 0;
 132                 if (elems->supp_rates) {
 133                         clen = IEEE80211_MAX_SUPP_RATES;
 134                         if (clen > elems->supp_rates_len)
 135                                 clen = elems->supp_rates_len;
 136                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 137                         srlen += clen;
 138                 }
 139                 if (elems->ext_supp_rates) {
 140                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 141                         if (clen > elems->ext_supp_rates_len)
 142                                 clen = elems->ext_supp_rates_len;
 143                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 144                                clen);
 145                         srlen += clen;
 146                 }
 147                 if (srlen) {
 148                         bss->supp_rates_len = srlen;
 149                         if (!elems->parse_error)
 150                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 151                 }
 152         }
 153
 154         if (!elems->parse_error ||
 155             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 156                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 157                 bss->uapsd_supported = is_uapsd_supported(elems);
 158                 if (!elems->parse_error)
 159                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 160         }
 161
 162         if (!beacon)
 163                 bss->last_probe_resp = jiffies;
 164
 165         return bss;
 166 }
 167
 168 ieee80211_rx_result
 169 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 170 {
 171         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 172         struct ieee80211_mgmt *mgmt;
 173         struct ieee80211_bss *bss;
 174         u8 *elements;
 175         struct ieee80211_channel *channel;
 176         size_t baselen;
 177         int freq;
 178         __le16 fc;
 179         bool presp, beacon = false;
 180         struct ieee802_11_elems elems;
 181
 182         if (skb->len < 2)
 183                 return RX_DROP_UNUSABLE;
 184
 185         mgmt = (struct ieee80211_mgmt *) skb->data;
 186         fc = mgmt->frame_control;
 187
 188         if (ieee80211_is_ctl(fc))
 189                 return RX_CONTINUE;
 190
 191         if (skb->len < 24)
 192                 return RX_CONTINUE;
 193
 194         presp = ieee80211_is_probe_resp(fc);
 195         if (presp) {
 196                 /* ignore ProbeResp to foreign address */
 197                 if (!ether_addr_equal(mgmt->da, sdata->vif.addr))
 198                         return RX_DROP_MONITOR;
 199
 200                 presp = true;
 201                 elements = mgmt->u.probe_resp.variable;
 202                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 203         } else {
 204                 beacon = ieee80211_is_beacon(fc);
 205                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 206                 elements = mgmt->u.beacon.variable;
 207         }
 208
 209         if (!presp && !beacon)
 210                 return RX_CONTINUE;
 211
 212         if (baselen > skb->len)
 213                 return RX_DROP_MONITOR;
 214
 215         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 216
 217         if (elems.ds_params && elems.ds_params_len == 1)
 218                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
 219                                                       rx_status->band);
 220         else
 221                 freq = rx_status->freq;
 222
 223         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 224
 225         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 226                 return RX_DROP_MONITOR;
 227
 228         bss = ieee80211_bss_info_update(sdata->local, rx_status,
 229                                         mgmt, skb->len, &elems,
 230                                         channel, beacon);
 231         if (bss)
 232                 ieee80211_rx_bss_put(sdata->local, bss);
 233
 234         if (channel == sdata->local->oper_channel)
 235                 return RX_CONTINUE;
 236
 237         dev_kfree_skb(skb);
 238         return RX_QUEUED;
 239 }
 240
 241 /* return false if no more work */
 242 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 243 {
 244         struct cfg80211_scan_request *req = local->scan_req;
 245         enum ieee80211_band band;
 246         int i, ielen, n_chans;
 247
 248         do {
 249                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 250                         return false;
 251
 252                 band = local->hw_scan_band;
 253                 n_chans = 0;
 254                 for (i = 0; i < req->n_channels; i++) {
 255                         if (req->channels[i]->band == band) {
 256                                 local->hw_scan_req->channels[n_chans] =
 257                                                         req->channels[i];
 258                                 n_chans++;
 259                         }
 260                 }
 261
 262                 local->hw_scan_band++;
 263         } while (!n_chans);
 264
 265         local->hw_scan_req->n_channels = n_chans;
 266
 267         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 268                                          req->ie, req->ie_len, band,
 269                                          req->rates[band], 0);
 270         local->hw_scan_req->ie_len = ielen;
 271         local->hw_scan_req->no_cck = req->no_cck;
 272
 273         return true;
 274 }
 275
 276 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 277                                        bool was_hw_scan)
 278 {
 279         struct ieee80211_local *local = hw_to_local(hw);
 280
 281         lockdep_assert_held(&local->mtx);
 282
 283         /*
 284          * It's ok to abort a not-yet-running scan (that
 285          * we have one at all will be verified by checking
 286          * local->scan_req next), but not to complete it
 287          * successfully.
 288          */
 289         if (WARN_ON(!local->scanning && !aborted))
 290                 aborted = true;
 291
 292         if (WARN_ON(!local->scan_req))
 293                 return;
 294
 295         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 296                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
 297                 if (rc == 0)
 298                         return;
 299         }
 300
 301         kfree(local->hw_scan_req);
 302         local->hw_scan_req = NULL;
 303
 304         if (local->scan_req != local->int_scan_req)
 305                 cfg80211_scan_done(local->scan_req, aborted);
 306         local->scan_req = NULL;
 307         rcu_assign_pointer(local->scan_sdata, NULL);
 308
 309         local->scanning = 0;
 310         local->scan_channel = NULL;
 311
 312         /* Set power back to normal operating levels. */
 313         ieee80211_hw_config(local, 0);
 314
 315         if (!was_hw_scan) {
 316                 ieee80211_configure_filter(local);
 317                 drv_sw_scan_complete(local);
 318                 ieee80211_offchannel_return(local, 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 = jiffies;
 360         local->next_scan_state = SCAN_DECISION;
 361         local->scan_channel_idx = 0;
 362
 363         ieee80211_offchannel_stop_vifs(local, true);
 364
 365         ieee80211_configure_filter(local);
 366
 367         /* We need to set power level at maximum rate for scanning. */
 368         ieee80211_hw_config(local, 0);
 369
 370         ieee80211_queue_delayed_work(&local->hw,
 371                                      &local->scan_work, 0);
 372
 373         return 0;
 374 }
 375
 376 static bool ieee80211_can_scan(struct ieee80211_local *local,
 377                                struct ieee80211_sub_if_data *sdata)
 378 {
 379         if (!list_empty(&local->work_list))
 380                 return false;
 381
 382         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 383             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 384                                   IEEE80211_STA_CONNECTION_POLL))
 385                 return false;
 386
 387         return true;
 388 }
 389
 390 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 391 {
 392         lockdep_assert_held(&local->mtx);
 393
 394         if (!local->scan_req || local->scanning)
 395                 return;
 396
 397         if (!ieee80211_can_scan(local, local->scan_sdata))
 398                 return;
 399
 400         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 401                                      round_jiffies_relative(0));
 402 }
 403
 404 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 405                                             unsigned long *next_delay)
 406 {
 407         int i;
 408         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 409         enum ieee80211_band band = local->hw.conf.channel->band;
 410
 411         for (i = 0; i < local->scan_req->n_ssids; i++)
 412                 ieee80211_send_probe_req(
 413                         sdata, NULL,
 414                         local->scan_req->ssids[i].ssid,
 415                         local->scan_req->ssids[i].ssid_len,
 416                         local->scan_req->ie, local->scan_req->ie_len,
 417                         local->scan_req->rates[band], false,
 418                         local->scan_req->no_cck);
 419
 420         /*
 421          * After sending probe requests, wait for probe responses
 422          * on the channel.
 423          */
 424         *next_delay = IEEE80211_CHANNEL_TIME;
 425         local->next_scan_state = SCAN_DECISION;
 426 }
 427
 428 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 429                                   struct cfg80211_scan_request *req)
 430 {
 431         struct ieee80211_local *local = sdata->local;
 432         int rc;
 433
 434         lockdep_assert_held(&local->mtx);
 435
 436         if (local->scan_req)
 437                 return -EBUSY;
 438
 439         if (!ieee80211_can_scan(local, sdata)) {
 440                 /* wait for the work to finish/time out */
 441                 local->scan_req = req;
 442                 local->scan_sdata = sdata;
 443                 return 0;
 444         }
 445
 446         if (local->ops->hw_scan) {
 447                 u8 *ies;
 448
 449                 local->hw_scan_req = kmalloc(
 450                                 sizeof(*local->hw_scan_req) +
 451                                 req->n_channels * sizeof(req->channels[0]) +
 452                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 453                                 req->ie_len, GFP_KERNEL);
 454                 if (!local->hw_scan_req)
 455                         return -ENOMEM;
 456
 457                 local->hw_scan_req->ssids = req->ssids;
 458                 local->hw_scan_req->n_ssids = req->n_ssids;
 459                 ies = (u8 *)local->hw_scan_req +
 460                         sizeof(*local->hw_scan_req) +
 461                         req->n_channels * sizeof(req->channels[0]);
 462                 local->hw_scan_req->ie = ies;
 463
 464                 local->hw_scan_band = 0;
 465
 466                 /*
 467                  * After allocating local->hw_scan_req, we must
 468                  * go through until ieee80211_prep_hw_scan(), so
 469                  * anything that might be changed here and leave
 470                  * this function early must not go after this
 471                  * allocation.
 472                  */
 473         }
 474
 475         local->scan_req = req;
 476         local->scan_sdata = sdata;
 477
 478         if (local->ops->hw_scan) {
 479                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 480         } else if ((req->n_channels == 1) &&
 481                    (req->channels[0]->center_freq ==
 482                     local->hw.conf.channel->center_freq)) {
 483
 484                 /* If we are scanning only on the current channel, then
 485                  * we do not need to stop normal activities
 486                  */
 487                 unsigned long next_delay;
 488
 489                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 490
 491                 ieee80211_recalc_idle(local);
 492
 493                 /* Notify driver scan is starting, keep order of operations
 494                  * same as normal software scan, in case that matters. */
 495                 drv_sw_scan_start(local);
 496
 497                 ieee80211_configure_filter(local); /* accept probe-responses */
 498
 499                 /* We need to ensure power level is at max for scanning. */
 500                 ieee80211_hw_config(local, 0);
 501
 502                 if ((req->channels[0]->flags &
 503                      IEEE80211_CHAN_PASSIVE_SCAN) ||
 504                     !local->scan_req->n_ssids) {
 505                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 506                 } else {
 507                         ieee80211_scan_state_send_probe(local, &next_delay);
 508                         next_delay = IEEE80211_CHANNEL_TIME;
 509                 }
 510
 511                 /* Now, just wait a bit and we are all done! */
 512                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 513                                              next_delay);
 514                 return 0;
 515         } else {
 516                 /* Do normal software scan */
 517                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 518         }
 519
 520         ieee80211_recalc_idle(local);
 521
 522         if (local->ops->hw_scan) {
 523                 WARN_ON(!ieee80211_prep_hw_scan(local));
 524                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 525         } else
 526                 rc = ieee80211_start_sw_scan(local);
 527
 528         if (rc) {
 529                 kfree(local->hw_scan_req);
 530                 local->hw_scan_req = NULL;
 531                 local->scanning = 0;
 532
 533                 ieee80211_recalc_idle(local);
 534
 535                 local->scan_req = NULL;
 536                 local->scan_sdata = NULL;
 537         }
 538
 539         return rc;
 540 }
 541
 542 static unsigned long
 543 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 544 {
 545         /*
 546          * TODO: channel switching also consumes quite some time,
 547          * add that delay as well to get a better estimation
 548          */
 549         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 550                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 551         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 552 }
 553
 554 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 555                                           unsigned long *next_delay)
 556 {
 557         bool associated = false;
 558         bool tx_empty = true;
 559         bool bad_latency;
 560         bool listen_int_exceeded;
 561         unsigned long min_beacon_int = 0;
 562         struct ieee80211_sub_if_data *sdata;
 563         struct ieee80211_channel *next_chan;
 564
 565         /*
 566          * check if at least one STA interface is associated,
 567          * check if at least one STA interface has pending tx frames
 568          * and grab the lowest used beacon interval
 569          */
 570         mutex_lock(&local->iflist_mtx);
 571         list_for_each_entry(sdata, &local->interfaces, list) {
 572                 if (!ieee80211_sdata_running(sdata))
 573                         continue;
 574
 575                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 576                         if (sdata->u.mgd.associated) {
 577                                 associated = true;
 578
 579                                 if (sdata->vif.bss_conf.beacon_int <
 580                                     min_beacon_int || min_beacon_int == 0)
 581                                         min_beacon_int =
 582                                                 sdata->vif.bss_conf.beacon_int;
 583
 584                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 585                                         tx_empty = false;
 586                                         break;
 587                                 }
 588                         }
 589                 }
 590         }
 591         mutex_unlock(&local->iflist_mtx);
 592
 593         next_chan = local->scan_req->channels[local->scan_channel_idx];
 594
 595         /*
 596          * we're currently scanning a different channel, let's
 597          * see if we can scan another channel without interfering
 598          * with the current traffic situation.
 599          *
 600          * Since we don't know if the AP has pending frames for us
 601          * we can only check for our tx queues and use the current
 602          * pm_qos requirements for rx. Hence, if no tx traffic occurs
 603          * at all we will scan as many channels in a row as the pm_qos
 604          * latency allows us to. Additionally we also check for the
 605          * currently negotiated listen interval to prevent losing
 606          * frames unnecessarily.
 607          *
 608          * Otherwise switch back to the operating channel.
 609          */
 610
 611         bad_latency = time_after(jiffies +
 612                         ieee80211_scan_get_channel_time(next_chan),
 613                         local->leave_oper_channel_time +
 614                         usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 615
 616         listen_int_exceeded = time_after(jiffies +
 617                         ieee80211_scan_get_channel_time(next_chan),
 618                         local->leave_oper_channel_time +
 619                         usecs_to_jiffies(min_beacon_int * 1024) *
 620                         local->hw.conf.listen_interval);
 621
 622         if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
 623                 local->next_scan_state = SCAN_SUSPEND;
 624         else
 625                 local->next_scan_state = SCAN_SET_CHANNEL;
 626
 627         *next_delay = 0;
 628 }
 629
 630 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 631                                              unsigned long *next_delay)
 632 {
 633         int skip;
 634         struct ieee80211_channel *chan;
 635
 636         skip = 0;
 637         chan = local->scan_req->channels[local->scan_channel_idx];
 638
 639         local->scan_channel = chan;
 640
 641         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 642                 skip = 1;
 643
 644         /* advance state machine to next channel/band */
 645         local->scan_channel_idx++;
 646
 647         if (skip) {
 648                 /* if we skip this channel return to the decision state */
 649                 local->next_scan_state = SCAN_DECISION;
 650                 return;
 651         }
 652
 653         /*
 654          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 655          * (which unfortunately doesn't say _why_ step a) is done,
 656          * but it waits for the probe delay or until a frame is
 657          * received - and the received frame would update the NAV).
 658          * For now, we do not support waiting until a frame is
 659          * received.
 660          *
 661          * In any case, it is not necessary for a passive scan.
 662          */
 663         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 664             !local->scan_req->n_ssids) {
 665                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 666                 local->next_scan_state = SCAN_DECISION;
 667                 return;
 668         }
 669
 670         /* active scan, send probes */
 671         *next_delay = IEEE80211_PROBE_DELAY;
 672         local->next_scan_state = SCAN_SEND_PROBE;
 673 }
 674
 675 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 676                                          unsigned long *next_delay)
 677 {
 678         /* switch back to the operating channel */
 679         local->scan_channel = NULL;
 680         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 681
 682         /*
 683          * Re-enable vifs and beaconing.  Leave PS
 684          * in off-channel state..will put that back
 685          * on-channel at the end of scanning.
 686          */
 687         ieee80211_offchannel_return(local, false);
 688
 689         *next_delay = HZ / 5;
 690         /* afterwards, resume scan & go to next channel */
 691         local->next_scan_state = SCAN_RESUME;
 692 }
 693
 694 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 695                                         unsigned long *next_delay)
 696 {
 697         /* PS already is in off-channel mode */
 698         ieee80211_offchannel_stop_vifs(local, false);
 699
 700         if (local->ops->flush) {
 701                 drv_flush(local, false);
 702                 *next_delay = 0;
 703         } else
 704                 *next_delay = HZ / 10;
 705
 706         /* remember when we left the operating channel */
 707         local->leave_oper_channel_time = jiffies;
 708
 709         /* advance to the next channel to be scanned */
 710         local->next_scan_state = SCAN_SET_CHANNEL;
 711 }
 712
 713 void ieee80211_scan_work(struct work_struct *work)
 714 {
 715         struct ieee80211_local *local =
 716                 container_of(work, struct ieee80211_local, scan_work.work);
 717         struct ieee80211_sub_if_data *sdata;
 718         unsigned long next_delay = 0;
 719         bool aborted, hw_scan;
 720
 721         mutex_lock(&local->mtx);
 722
 723         sdata = local->scan_sdata;
 724
 725         /* When scanning on-channel, the first-callback means completed. */
 726         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 727                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 728                 goto out_complete;
 729         }
 730
 731         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 732                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 733                 goto out_complete;
 734         }
 735
 736         if (!sdata || !local->scan_req)
 737                 goto out;
 738
 739         if (local->scan_req && !local->scanning) {
 740                 struct cfg80211_scan_request *req = local->scan_req;
 741                 int rc;
 742
 743                 local->scan_req = NULL;
 744                 local->scan_sdata = NULL;
 745
 746                 rc = __ieee80211_start_scan(sdata, req);
 747                 if (rc) {
 748                         /* need to complete scan in cfg80211 */
 749                         local->scan_req = req;
 750                         aborted = true;
 751                         goto out_complete;
 752                 } else
 753                         goto out;
 754         }
 755
 756         /*
 757          * Avoid re-scheduling when the sdata is going away.
 758          */
 759         if (!ieee80211_sdata_running(sdata)) {
 760                 aborted = true;
 761                 goto out_complete;
 762         }
 763
 764         /*
 765          * as long as no delay is required advance immediately
 766          * without scheduling a new work
 767          */
 768         do {
 769                 if (!ieee80211_sdata_running(sdata)) {
 770                         aborted = true;
 771                         goto out_complete;
 772                 }
 773
 774                 switch (local->next_scan_state) {
 775                 case SCAN_DECISION:
 776                         /* if no more bands/channels left, complete scan */
 777                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 778                                 aborted = false;
 779                                 goto out_complete;
 780                         }
 781                         ieee80211_scan_state_decision(local, &next_delay);
 782                         break;
 783                 case SCAN_SET_CHANNEL:
 784                         ieee80211_scan_state_set_channel(local, &next_delay);
 785                         break;
 786                 case SCAN_SEND_PROBE:
 787                         ieee80211_scan_state_send_probe(local, &next_delay);
 788                         break;
 789                 case SCAN_SUSPEND:
 790                         ieee80211_scan_state_suspend(local, &next_delay);
 791                         break;
 792                 case SCAN_RESUME:
 793                         ieee80211_scan_state_resume(local, &next_delay);
 794                         break;
 795                 }
 796         } while (next_delay == 0);
 797
 798         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 799         goto out;
 800
 801 out_complete:
 802         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 803         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 804 out:
 805         mutex_unlock(&local->mtx);
 806 }
 807
 808 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 809                            struct cfg80211_scan_request *req)
 810 {
 811         int res;
 812
 813         mutex_lock(&sdata->local->mtx);
 814         res = __ieee80211_start_scan(sdata, req);
 815         mutex_unlock(&sdata->local->mtx);
 816
 817         return res;
 818 }
 819
 820 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 821                                     const u8 *ssid, u8 ssid_len,
 822                                     struct ieee80211_channel *chan)
 823 {
 824         struct ieee80211_local *local = sdata->local;
 825         int ret = -EBUSY;
 826         enum ieee80211_band band;
 827
 828         mutex_lock(&local->mtx);
 829
 830         /* busy scanning */
 831         if (local->scan_req)
 832                 goto unlock;
 833
 834         /* fill internal scan request */
 835         if (!chan) {
 836                 int i, nchan = 0;
 837
 838                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 839                         if (!local->hw.wiphy->bands[band])
 840                                 continue;
 841                         for (i = 0;
 842                              i < local->hw.wiphy->bands[band]->n_channels;
 843                              i++) {
 844                                 local->int_scan_req->channels[nchan] =
 845                                     &local->hw.wiphy->bands[band]->channels[i];
 846                                 nchan++;
 847                         }
 848                 }
 849
 850                 local->int_scan_req->n_channels = nchan;
 851         } else {
 852                 local->int_scan_req->channels[0] = chan;
 853                 local->int_scan_req->n_channels = 1;
 854         }
 855
 856         local->int_scan_req->ssids = &local->scan_ssid;
 857         local->int_scan_req->n_ssids = 1;
 858         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 859         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 860
 861         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 862  unlock:
 863         mutex_unlock(&local->mtx);
 864         return ret;
 865 }
 866
 867 /*
 868  * Only call this function when a scan can't be queued -- under RTNL.
 869  */
 870 void ieee80211_scan_cancel(struct ieee80211_local *local)
 871 {
 872         /*
 873          * We are canceling software scan, or deferred scan that was not
 874          * yet really started (see __ieee80211_start_scan ).
 875          *
 876          * Regarding hardware scan:
 877          * - we can not call  __ieee80211_scan_completed() as when
 878          *   SCAN_HW_SCANNING bit is set this function change
 879          *   local->hw_scan_req to operate on 5G band, what race with
 880          *   driver which can use local->hw_scan_req
 881          *
 882          * - we can not cancel scan_work since driver can schedule it
 883          *   by ieee80211_scan_completed(..., true) to finish scan
 884          *
 885          * Hence we only call the cancel_hw_scan() callback, but the low-level
 886          * driver is still responsible for calling ieee80211_scan_completed()
 887          * after the scan was completed/aborted.
 888          */
 889
 890         mutex_lock(&local->mtx);
 891         if (!local->scan_req)
 892                 goto out;
 893
 894         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 895                 if (local->ops->cancel_hw_scan)
 896                         drv_cancel_hw_scan(local, local->scan_sdata);
 897                 goto out;
 898         }
 899
 900         /*
 901          * If the work is currently running, it must be blocked on
 902          * the mutex, but we'll set scan_sdata = NULL and it'll
 903          * simply exit once it acquires the mutex.
 904          */
 905         cancel_delayed_work(&local->scan_work);
 906         /* and clean up */
 907         __ieee80211_scan_completed(&local->hw, true, false);
 908 out:
 909         mutex_unlock(&local->mtx);
 910 }
 911
 912 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 913                                        struct cfg80211_sched_scan_request *req)
 914 {
 915         struct ieee80211_local *local = sdata->local;
 916         int ret, i;
 917
 918         mutex_lock(&sdata->local->mtx);
 919
 920         if (local->sched_scanning) {
 921                 ret = -EBUSY;
 922                 goto out;
 923         }
 924
 925         if (!local->ops->sched_scan_start) {
 926                 ret = -ENOTSUPP;
 927                 goto out;
 928         }
 929
 930         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 931                 local->sched_scan_ies.ie[i] = kzalloc(2 +
 932                                                       IEEE80211_MAX_SSID_LEN +
 933                                                       local->scan_ies_len +
 934                                                       req->ie_len,
 935                                                       GFP_KERNEL);
 936                 if (!local->sched_scan_ies.ie[i]) {
 937                         ret = -ENOMEM;
 938                         goto out_free;
 939                 }
 940
 941                 local->sched_scan_ies.len[i] =
 942                         ieee80211_build_preq_ies(local,
 943                                                  local->sched_scan_ies.ie[i],
 944                                                  req->ie, req->ie_len, i,
 945                                                  (u32) -1, 0);
 946         }
 947
 948         ret = drv_sched_scan_start(local, sdata, req,
 949                                    &local->sched_scan_ies);
 950         if (ret == 0) {
 951                 local->sched_scanning = true;
 952                 goto out;
 953         }
 954
 955 out_free:
 956         while (i > 0)
 957                 kfree(local->sched_scan_ies.ie[--i]);
 958 out:
 959         mutex_unlock(&sdata->local->mtx);
 960         return ret;
 961 }
 962
 963 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 964 {
 965         struct ieee80211_local *local = sdata->local;
 966         int ret = 0, i;
 967
 968         mutex_lock(&sdata->local->mtx);
 969
 970         if (!local->ops->sched_scan_stop) {
 971                 ret = -ENOTSUPP;
 972                 goto out;
 973         }
 974
 975         if (local->sched_scanning) {
 976                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 977                         kfree(local->sched_scan_ies.ie[i]);
 978
 979                 drv_sched_scan_stop(local, sdata);
 980                 local->sched_scanning = false;
 981         }
 982 out:
 983         mutex_unlock(&sdata->local->mtx);
 984
 985         return ret;
 986 }
 987
 988 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 989 {
 990         struct ieee80211_local *local = hw_to_local(hw);
 991
 992         trace_api_sched_scan_results(local);
 993
 994         cfg80211_sched_scan_results(hw->wiphy);
 995 }
 996 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 997
 998 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 999 {
1000         struct ieee80211_local *local =
1001                 container_of(work, struct ieee80211_local,
1002                              sched_scan_stopped_work);
1003         int i;
1004
1005         mutex_lock(&local->mtx);
1006
1007         if (!local->sched_scanning) {
1008                 mutex_unlock(&local->mtx);
1009                 return;
1010         }
1011
1012         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
1013                 kfree(local->sched_scan_ies.ie[i]);
1014
1015         local->sched_scanning = false;
1016
1017         mutex_unlock(&local->mtx);
1018
1019         cfg80211_sched_scan_stopped(local->hw.wiphy);
1020 }
1021
1022 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1023 {
1024         struct ieee80211_local *local = hw_to_local(hw);
1025
1026         trace_api_sched_scan_stopped(local);
1027
1028         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1029 }
1030 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);