linux/net/mac80211/scan.c
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   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
  32static 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
  40void 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
  48static 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
  65struct ieee80211_bss *
  66ieee80211_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        if (!cbss)
  87                return NULL;
  88
  89        cbss->free_priv = ieee80211_rx_bss_free;
  90        bss = (void *)cbss->priv;
  91
  92        bss->device_ts = rx_status->device_timestamp;
  93
  94        if (elems->parse_error) {
  95                if (beacon)
  96                        bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  97                else
  98                        bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  99        } else {
 100                if (beacon)
 101                        bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 102                else
 103                        bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 104        }
 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                        (!elems->parse_error ||
 109                         !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 110                bss->erp_value = elems->erp_info[0];
 111                bss->has_erp_value = true;
 112                if (!elems->parse_error)
 113                        bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 114        }
 115
 116        if (elems->tim && (!elems->parse_error ||
 117                           !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) {
 118                struct ieee80211_tim_ie *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
 168void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 169{
 170        struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 171        struct ieee80211_sub_if_data *sdata1, *sdata2;
 172        struct ieee80211_mgmt *mgmt = (void *)skb->data;
 173        struct ieee80211_bss *bss;
 174        u8 *elements;
 175        struct ieee80211_channel *channel;
 176        size_t baselen;
 177        int freq;
 178        bool beacon;
 179        struct ieee802_11_elems elems;
 180
 181        if (skb->len < 24 ||
 182            (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 183             !ieee80211_is_beacon(mgmt->frame_control)))
 184                return;
 185
 186        sdata1 = rcu_dereference(local->scan_sdata);
 187        sdata2 = rcu_dereference(local->sched_scan_sdata);
 188
 189        if (likely(!sdata1 && !sdata2))
 190                return;
 191
 192        if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 193                /* ignore ProbeResp to foreign address */
 194                if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
 195                    (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
 196                        return;
 197
 198                elements = mgmt->u.probe_resp.variable;
 199                baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 200                beacon = false;
 201        } else {
 202                baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 203                elements = mgmt->u.beacon.variable;
 204                beacon = true;
 205        }
 206
 207        if (baselen > skb->len)
 208                return;
 209
 210        ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 211
 212        if (elems.ds_params && elems.ds_params_len == 1)
 213                freq = ieee80211_channel_to_frequency(elems.ds_params[0],
 214                                                      rx_status->band);
 215        else
 216                freq = rx_status->freq;
 217
 218        channel = ieee80211_get_channel(local->hw.wiphy, freq);
 219
 220        if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 221                return;
 222
 223        bss = ieee80211_bss_info_update(local, rx_status,
 224                                        mgmt, skb->len, &elems,
 225                                        channel, beacon);
 226        if (bss)
 227                ieee80211_rx_bss_put(local, bss);
 228}
 229
 230/* return false if no more work */
 231static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 232{
 233        struct cfg80211_scan_request *req = local->scan_req;
 234        enum ieee80211_band band;
 235        int i, ielen, n_chans;
 236
 237        do {
 238                if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 239                        return false;
 240
 241                band = local->hw_scan_band;
 242                n_chans = 0;
 243                for (i = 0; i < req->n_channels; i++) {
 244                        if (req->channels[i]->band == band) {
 245                                local->hw_scan_req->channels[n_chans] =
 246                                                        req->channels[i];
 247                                n_chans++;
 248                        }
 249                }
 250
 251                local->hw_scan_band++;
 252        } while (!n_chans);
 253
 254        local->hw_scan_req->n_channels = n_chans;
 255
 256        ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 257                                         req->ie, req->ie_len, band,
 258                                         req->rates[band], 0);
 259        local->hw_scan_req->ie_len = ielen;
 260        local->hw_scan_req->no_cck = req->no_cck;
 261
 262        return true;
 263}
 264
 265static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 266                                       bool was_hw_scan)
 267{
 268        struct ieee80211_local *local = hw_to_local(hw);
 269
 270        lockdep_assert_held(&local->mtx);
 271
 272        /*
 273         * It's ok to abort a not-yet-running scan (that
 274         * we have one at all will be verified by checking
 275         * local->scan_req next), but not to complete it
 276         * successfully.
 277         */
 278        if (WARN_ON(!local->scanning && !aborted))
 279                aborted = true;
 280
 281        if (WARN_ON(!local->scan_req))
 282                return;
 283
 284        if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 285                int rc;
 286
 287                rc = drv_hw_scan(local,
 288                        rcu_dereference_protected(local->scan_sdata,
 289                                                  lockdep_is_held(&local->mtx)),
 290                        local->hw_scan_req);
 291
 292                if (rc == 0)
 293                        return;
 294        }
 295
 296        kfree(local->hw_scan_req);
 297        local->hw_scan_req = NULL;
 298
 299        if (local->scan_req != local->int_scan_req)
 300                cfg80211_scan_done(local->scan_req, aborted);
 301        local->scan_req = NULL;
 302        rcu_assign_pointer(local->scan_sdata, NULL);
 303
 304        local->scanning = 0;
 305        local->scan_channel = NULL;
 306
 307        /* Set power back to normal operating levels. */
 308        ieee80211_hw_config(local, 0);
 309
 310        if (!was_hw_scan) {
 311                ieee80211_configure_filter(local);
 312                drv_sw_scan_complete(local);
 313                ieee80211_offchannel_return(local, true);
 314        }
 315
 316        ieee80211_recalc_idle(local);
 317
 318        ieee80211_mlme_notify_scan_completed(local);
 319        ieee80211_ibss_notify_scan_completed(local);
 320        ieee80211_mesh_notify_scan_completed(local);
 321        ieee80211_start_next_roc(local);
 322}
 323
 324void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 325{
 326        struct ieee80211_local *local = hw_to_local(hw);
 327
 328        trace_api_scan_completed(local, aborted);
 329
 330        set_bit(SCAN_COMPLETED, &local->scanning);
 331        if (aborted)
 332                set_bit(SCAN_ABORTED, &local->scanning);
 333        ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 334}
 335EXPORT_SYMBOL(ieee80211_scan_completed);
 336
 337static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 338{
 339        /*
 340         * Hardware/driver doesn't support hw_scan, so use software
 341         * scanning instead. First send a nullfunc frame with power save
 342         * bit on so that AP will buffer the frames for us while we are not
 343         * listening, then send probe requests to each channel and wait for
 344         * the responses. After all channels are scanned, tune back to the
 345         * original channel and send a nullfunc frame with power save bit
 346         * off to trigger the AP to send us all the buffered frames.
 347         *
 348         * Note that while local->sw_scanning is true everything else but
 349         * nullfunc frames and probe requests will be dropped in
 350         * ieee80211_tx_h_check_assoc().
 351         */
 352        drv_sw_scan_start(local);
 353
 354        local->leave_oper_channel_time = jiffies;
 355        local->next_scan_state = SCAN_DECISION;
 356        local->scan_channel_idx = 0;
 357
 358        ieee80211_offchannel_stop_vifs(local, true);
 359
 360        ieee80211_configure_filter(local);
 361
 362        /* We need to set power level at maximum rate for scanning. */
 363        ieee80211_hw_config(local, 0);
 364
 365        ieee80211_queue_delayed_work(&local->hw,
 366                                     &local->scan_work, 0);
 367
 368        return 0;
 369}
 370
 371static bool ieee80211_can_scan(struct ieee80211_local *local,
 372                               struct ieee80211_sub_if_data *sdata)
 373{
 374        if (!list_empty(&local->roc_list))
 375                return false;
 376
 377        if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 378            sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 379                                  IEEE80211_STA_CONNECTION_POLL))
 380                return false;
 381
 382        return true;
 383}
 384
 385void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 386{
 387        lockdep_assert_held(&local->mtx);
 388
 389        if (!local->scan_req || local->scanning)
 390                return;
 391
 392        if (!ieee80211_can_scan(local,
 393                                rcu_dereference_protected(
 394                                        local->scan_sdata,
 395                                        lockdep_is_held(&local->mtx))))
 396                return;
 397
 398        ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 399                                     round_jiffies_relative(0));
 400}
 401
 402static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 403                                            unsigned long *next_delay)
 404{
 405        int i;
 406        struct ieee80211_sub_if_data *sdata;
 407        enum ieee80211_band band = local->hw.conf.channel->band;
 408
 409        sdata = rcu_dereference_protected(local->scan_sdata,
 410                                          lockdep_is_held(&local->mtx));
 411
 412        for (i = 0; i < local->scan_req->n_ssids; i++)
 413                ieee80211_send_probe_req(
 414                        sdata, NULL,
 415                        local->scan_req->ssids[i].ssid,
 416                        local->scan_req->ssids[i].ssid_len,
 417                        local->scan_req->ie, local->scan_req->ie_len,
 418                        local->scan_req->rates[band], false,
 419                        local->scan_req->no_cck,
 420                        local->hw.conf.channel);
 421
 422        /*
 423         * After sending probe requests, wait for probe responses
 424         * on the channel.
 425         */
 426        *next_delay = IEEE80211_CHANNEL_TIME;
 427        local->next_scan_state = SCAN_DECISION;
 428}
 429
 430static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 431                                  struct cfg80211_scan_request *req)
 432{
 433        struct ieee80211_local *local = sdata->local;
 434        int rc;
 435
 436        lockdep_assert_held(&local->mtx);
 437
 438        if (local->scan_req)
 439                return -EBUSY;
 440
 441        if (!ieee80211_can_scan(local, sdata)) {
 442                /* wait for the work to finish/time out */
 443                local->scan_req = req;
 444                rcu_assign_pointer(local->scan_sdata, sdata);
 445                return 0;
 446        }
 447
 448        if (local->ops->hw_scan) {
 449                u8 *ies;
 450
 451                local->hw_scan_req = kmalloc(
 452                                sizeof(*local->hw_scan_req) +
 453                                req->n_channels * sizeof(req->channels[0]) +
 454                                2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 455                                req->ie_len, GFP_KERNEL);
 456                if (!local->hw_scan_req)
 457                        return -ENOMEM;
 458
 459                local->hw_scan_req->ssids = req->ssids;
 460                local->hw_scan_req->n_ssids = req->n_ssids;
 461                ies = (u8 *)local->hw_scan_req +
 462                        sizeof(*local->hw_scan_req) +
 463                        req->n_channels * sizeof(req->channels[0]);
 464                local->hw_scan_req->ie = ies;
 465
 466                local->hw_scan_band = 0;
 467
 468                /*
 469                 * After allocating local->hw_scan_req, we must
 470                 * go through until ieee80211_prep_hw_scan(), so
 471                 * anything that might be changed here and leave
 472                 * this function early must not go after this
 473                 * allocation.
 474                 */
 475        }
 476
 477        local->scan_req = req;
 478        rcu_assign_pointer(local->scan_sdata, sdata);
 479
 480        if (local->ops->hw_scan) {
 481                __set_bit(SCAN_HW_SCANNING, &local->scanning);
 482        } else if ((req->n_channels == 1) &&
 483                   (req->channels[0] == local->oper_channel)) {
 484                /*
 485                 * If we are scanning only on the operating channel
 486                 * then we do not need to stop normal activities
 487                 */
 488                unsigned long next_delay;
 489
 490                __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 491
 492                ieee80211_recalc_idle(local);
 493
 494                /* Notify driver scan is starting, keep order of operations
 495                 * same as normal software scan, in case that matters. */
 496                drv_sw_scan_start(local);
 497
 498                ieee80211_configure_filter(local); /* accept probe-responses */
 499
 500                /* We need to ensure power level is at max for scanning. */
 501                ieee80211_hw_config(local, 0);
 502
 503                if ((req->channels[0]->flags &
 504                     IEEE80211_CHAN_PASSIVE_SCAN) ||
 505                    !local->scan_req->n_ssids) {
 506                        next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 507                } else {
 508                        ieee80211_scan_state_send_probe(local, &next_delay);
 509                        next_delay = IEEE80211_CHANNEL_TIME;
 510                }
 511
 512                /* Now, just wait a bit and we are all done! */
 513                ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 514                                             next_delay);
 515                return 0;
 516        } else {
 517                /* Do normal software scan */
 518                __set_bit(SCAN_SW_SCANNING, &local->scanning);
 519        }
 520
 521        ieee80211_recalc_idle(local);
 522
 523        if (local->ops->hw_scan) {
 524                WARN_ON(!ieee80211_prep_hw_scan(local));
 525                rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 526        } else
 527                rc = ieee80211_start_sw_scan(local);
 528
 529        if (rc) {
 530                kfree(local->hw_scan_req);
 531                local->hw_scan_req = NULL;
 532                local->scanning = 0;
 533
 534                ieee80211_recalc_idle(local);
 535
 536                local->scan_req = NULL;
 537                rcu_assign_pointer(local->scan_sdata, NULL);
 538        }
 539
 540        return rc;
 541}
 542
 543static unsigned long
 544ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 545{
 546        /*
 547         * TODO: channel switching also consumes quite some time,
 548         * add that delay as well to get a better estimation
 549         */
 550        if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 551                return IEEE80211_PASSIVE_CHANNEL_TIME;
 552        return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 553}
 554
 555static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 556                                          unsigned long *next_delay)
 557{
 558        bool associated = false;
 559        bool tx_empty = true;
 560        bool bad_latency;
 561        bool listen_int_exceeded;
 562        unsigned long min_beacon_int = 0;
 563        struct ieee80211_sub_if_data *sdata;
 564        struct ieee80211_channel *next_chan;
 565
 566        /*
 567         * check if at least one STA interface is associated,
 568         * check if at least one STA interface has pending tx frames
 569         * and grab the lowest used beacon interval
 570         */
 571        mutex_lock(&local->iflist_mtx);
 572        list_for_each_entry(sdata, &local->interfaces, list) {
 573                if (!ieee80211_sdata_running(sdata))
 574                        continue;
 575
 576                if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 577                        if (sdata->u.mgd.associated) {
 578                                associated = true;
 579
 580                                if (sdata->vif.bss_conf.beacon_int <
 581                                    min_beacon_int || min_beacon_int == 0)
 582                                        min_beacon_int =
 583                                                sdata->vif.bss_conf.beacon_int;
 584
 585                                if (!qdisc_all_tx_empty(sdata->dev)) {
 586                                        tx_empty = false;
 587                                        break;
 588                                }
 589                        }
 590                }
 591        }
 592        mutex_unlock(&local->iflist_mtx);
 593
 594        next_chan = local->scan_req->channels[local->scan_channel_idx];
 595
 596        /*
 597         * we're currently scanning a different channel, let's
 598         * see if we can scan another channel without interfering
 599         * with the current traffic situation.
 600         *
 601         * Since we don't know if the AP has pending frames for us
 602         * we can only check for our tx queues and use the current
 603         * pm_qos requirements for rx. Hence, if no tx traffic occurs
 604         * at all we will scan as many channels in a row as the pm_qos
 605         * latency allows us to. Additionally we also check for the
 606         * currently negotiated listen interval to prevent losing
 607         * frames unnecessarily.
 608         *
 609         * Otherwise switch back to the operating channel.
 610         */
 611
 612        bad_latency = time_after(jiffies +
 613                        ieee80211_scan_get_channel_time(next_chan),
 614                        local->leave_oper_channel_time +
 615                        usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 616
 617        listen_int_exceeded = time_after(jiffies +
 618                        ieee80211_scan_get_channel_time(next_chan),
 619                        local->leave_oper_channel_time +
 620                        usecs_to_jiffies(min_beacon_int * 1024) *
 621                        local->hw.conf.listen_interval);
 622
 623        if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
 624                local->next_scan_state = SCAN_SUSPEND;
 625        else
 626                local->next_scan_state = SCAN_SET_CHANNEL;
 627
 628        *next_delay = 0;
 629}
 630
 631static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 632                                             unsigned long *next_delay)
 633{
 634        int skip;
 635        struct ieee80211_channel *chan;
 636
 637        skip = 0;
 638        chan = local->scan_req->channels[local->scan_channel_idx];
 639
 640        local->scan_channel = chan;
 641
 642        if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 643                skip = 1;
 644
 645        /* advance state machine to next channel/band */
 646        local->scan_channel_idx++;
 647
 648        if (skip) {
 649                /* if we skip this channel return to the decision state */
 650                local->next_scan_state = SCAN_DECISION;
 651                return;
 652        }
 653
 654        /*
 655         * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 656         * (which unfortunately doesn't say _why_ step a) is done,
 657         * but it waits for the probe delay or until a frame is
 658         * received - and the received frame would update the NAV).
 659         * For now, we do not support waiting until a frame is
 660         * received.
 661         *
 662         * In any case, it is not necessary for a passive scan.
 663         */
 664        if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 665            !local->scan_req->n_ssids) {
 666                *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 667                local->next_scan_state = SCAN_DECISION;
 668                return;
 669        }
 670
 671        /* active scan, send probes */
 672        *next_delay = IEEE80211_PROBE_DELAY;
 673        local->next_scan_state = SCAN_SEND_PROBE;
 674}
 675
 676static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 677                                         unsigned long *next_delay)
 678{
 679        /* switch back to the operating channel */
 680        local->scan_channel = NULL;
 681        ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 682
 683        /*
 684         * Re-enable vifs and beaconing.  Leave PS
 685         * in off-channel state..will put that back
 686         * on-channel at the end of scanning.
 687         */
 688        ieee80211_offchannel_return(local, false);
 689
 690        *next_delay = HZ / 5;
 691        /* afterwards, resume scan & go to next channel */
 692        local->next_scan_state = SCAN_RESUME;
 693}
 694
 695static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 696                                        unsigned long *next_delay)
 697{
 698        /* PS already is in off-channel mode */
 699        ieee80211_offchannel_stop_vifs(local, false);
 700
 701        if (local->ops->flush) {
 702                drv_flush(local, false);
 703                *next_delay = 0;
 704        } else
 705                *next_delay = HZ / 10;
 706
 707        /* remember when we left the operating channel */
 708        local->leave_oper_channel_time = jiffies;
 709
 710        /* advance to the next channel to be scanned */
 711        local->next_scan_state = SCAN_SET_CHANNEL;
 712}
 713
 714void ieee80211_scan_work(struct work_struct *work)
 715{
 716        struct ieee80211_local *local =
 717                container_of(work, struct ieee80211_local, scan_work.work);
 718        struct ieee80211_sub_if_data *sdata;
 719        unsigned long next_delay = 0;
 720        bool aborted, hw_scan;
 721
 722        mutex_lock(&local->mtx);
 723
 724        sdata = rcu_dereference_protected(local->scan_sdata,
 725                                          lockdep_is_held(&local->mtx));
 726
 727        /* When scanning on-channel, the first-callback means completed. */
 728        if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 729                aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 730                goto out_complete;
 731        }
 732
 733        if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 734                aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 735                goto out_complete;
 736        }
 737
 738        if (!sdata || !local->scan_req)
 739                goto out;
 740
 741        if (local->scan_req && !local->scanning) {
 742                struct cfg80211_scan_request *req = local->scan_req;
 743                int rc;
 744
 745                local->scan_req = NULL;
 746                rcu_assign_pointer(local->scan_sdata, NULL);
 747
 748                rc = __ieee80211_start_scan(sdata, req);
 749                if (rc) {
 750                        /* need to complete scan in cfg80211 */
 751                        local->scan_req = req;
 752                        aborted = true;
 753                        goto out_complete;
 754                } else
 755                        goto out;
 756        }
 757
 758        /*
 759         * Avoid re-scheduling when the sdata is going away.
 760         */
 761        if (!ieee80211_sdata_running(sdata)) {
 762                aborted = true;
 763                goto out_complete;
 764        }
 765
 766        /*
 767         * as long as no delay is required advance immediately
 768         * without scheduling a new work
 769         */
 770        do {
 771                if (!ieee80211_sdata_running(sdata)) {
 772                        aborted = true;
 773                        goto out_complete;
 774                }
 775
 776                switch (local->next_scan_state) {
 777                case SCAN_DECISION:
 778                        /* if no more bands/channels left, complete scan */
 779                        if (local->scan_channel_idx >= local->scan_req->n_channels) {
 780                                aborted = false;
 781                                goto out_complete;
 782                        }
 783                        ieee80211_scan_state_decision(local, &next_delay);
 784                        break;
 785                case SCAN_SET_CHANNEL:
 786                        ieee80211_scan_state_set_channel(local, &next_delay);
 787                        break;
 788                case SCAN_SEND_PROBE:
 789                        ieee80211_scan_state_send_probe(local, &next_delay);
 790                        break;
 791                case SCAN_SUSPEND:
 792                        ieee80211_scan_state_suspend(local, &next_delay);
 793                        break;
 794                case SCAN_RESUME:
 795                        ieee80211_scan_state_resume(local, &next_delay);
 796                        break;
 797                }
 798        } while (next_delay == 0);
 799
 800        ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 801        goto out;
 802
 803out_complete:
 804        hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 805        __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 806out:
 807        mutex_unlock(&local->mtx);
 808}
 809
 810int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 811                           struct cfg80211_scan_request *req)
 812{
 813        int res;
 814
 815        mutex_lock(&sdata->local->mtx);
 816        res = __ieee80211_start_scan(sdata, req);
 817        mutex_unlock(&sdata->local->mtx);
 818
 819        return res;
 820}
 821
 822int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 823                                    const u8 *ssid, u8 ssid_len,
 824                                    struct ieee80211_channel *chan)
 825{
 826        struct ieee80211_local *local = sdata->local;
 827        int ret = -EBUSY;
 828        enum ieee80211_band band;
 829
 830        mutex_lock(&local->mtx);
 831
 832        /* busy scanning */
 833        if (local->scan_req)
 834                goto unlock;
 835
 836        /* fill internal scan request */
 837        if (!chan) {
 838                int i, nchan = 0;
 839
 840                for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 841                        if (!local->hw.wiphy->bands[band])
 842                                continue;
 843                        for (i = 0;
 844                             i < local->hw.wiphy->bands[band]->n_channels;
 845                             i++) {
 846                                local->int_scan_req->channels[nchan] =
 847                                    &local->hw.wiphy->bands[band]->channels[i];
 848                                nchan++;
 849                        }
 850                }
 851
 852                local->int_scan_req->n_channels = nchan;
 853        } else {
 854                local->int_scan_req->channels[0] = chan;
 855                local->int_scan_req->n_channels = 1;
 856        }
 857
 858        local->int_scan_req->ssids = &local->scan_ssid;
 859        local->int_scan_req->n_ssids = 1;
 860        memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 861        local->int_scan_req->ssids[0].ssid_len = ssid_len;
 862
 863        ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 864 unlock:
 865        mutex_unlock(&local->mtx);
 866        return ret;
 867}
 868
 869/*
 870 * Only call this function when a scan can't be queued -- under RTNL.
 871 */
 872void ieee80211_scan_cancel(struct ieee80211_local *local)
 873{
 874        /*
 875         * We are canceling software scan, or deferred scan that was not
 876         * yet really started (see __ieee80211_start_scan ).
 877         *
 878         * Regarding hardware scan:
 879         * - we can not call  __ieee80211_scan_completed() as when
 880         *   SCAN_HW_SCANNING bit is set this function change
 881         *   local->hw_scan_req to operate on 5G band, what race with
 882         *   driver which can use local->hw_scan_req
 883         *
 884         * - we can not cancel scan_work since driver can schedule it
 885         *   by ieee80211_scan_completed(..., true) to finish scan
 886         *
 887         * Hence we only call the cancel_hw_scan() callback, but the low-level
 888         * driver is still responsible for calling ieee80211_scan_completed()
 889         * after the scan was completed/aborted.
 890         */
 891
 892        mutex_lock(&local->mtx);
 893        if (!local->scan_req)
 894                goto out;
 895
 896        if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 897                if (local->ops->cancel_hw_scan)
 898                        drv_cancel_hw_scan(local,
 899                                rcu_dereference_protected(local->scan_sdata,
 900                                                lockdep_is_held(&local->mtx)));
 901                goto out;
 902        }
 903
 904        /*
 905         * If the work is currently running, it must be blocked on
 906         * the mutex, but we'll set scan_sdata = NULL and it'll
 907         * simply exit once it acquires the mutex.
 908         */
 909        cancel_delayed_work(&local->scan_work);
 910        /* and clean up */
 911        __ieee80211_scan_completed(&local->hw, true, false);
 912out:
 913        mutex_unlock(&local->mtx);
 914}
 915
 916int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 917                                       struct cfg80211_sched_scan_request *req)
 918{
 919        struct ieee80211_local *local = sdata->local;
 920        struct ieee80211_sched_scan_ies sched_scan_ies = {};
 921        int ret, i;
 922
 923        mutex_lock(&local->mtx);
 924
 925        if (rcu_access_pointer(local->sched_scan_sdata)) {
 926                ret = -EBUSY;
 927                goto out;
 928        }
 929
 930        if (!local->ops->sched_scan_start) {
 931                ret = -ENOTSUPP;
 932                goto out;
 933        }
 934
 935        for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 936                if (!local->hw.wiphy->bands[i])
 937                        continue;
 938
 939                sched_scan_ies.ie[i] = kzalloc(2 + IEEE80211_MAX_SSID_LEN +
 940                                               local->scan_ies_len +
 941                                               req->ie_len,
 942                                               GFP_KERNEL);
 943                if (!sched_scan_ies.ie[i]) {
 944                        ret = -ENOMEM;
 945                        goto out_free;
 946                }
 947
 948                sched_scan_ies.len[i] =
 949                        ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
 950                                                 req->ie, req->ie_len, i,
 951                                                 (u32) -1, 0);
 952        }
 953
 954        ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
 955        if (ret == 0)
 956                rcu_assign_pointer(local->sched_scan_sdata, sdata);
 957
 958out_free:
 959        while (i > 0)
 960                kfree(sched_scan_ies.ie[--i]);
 961out:
 962        mutex_unlock(&local->mtx);
 963        return ret;
 964}
 965
 966int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 967{
 968        struct ieee80211_local *local = sdata->local;
 969        int ret = 0;
 970
 971        mutex_lock(&local->mtx);
 972
 973        if (!local->ops->sched_scan_stop) {
 974                ret = -ENOTSUPP;
 975                goto out;
 976        }
 977
 978        if (rcu_access_pointer(local->sched_scan_sdata))
 979                drv_sched_scan_stop(local, sdata);
 980
 981out:
 982        mutex_unlock(&local->mtx);
 983
 984        return ret;
 985}
 986
 987void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 988{
 989        struct ieee80211_local *local = hw_to_local(hw);
 990
 991        trace_api_sched_scan_results(local);
 992
 993        cfg80211_sched_scan_results(hw->wiphy);
 994}
 995EXPORT_SYMBOL(ieee80211_sched_scan_results);
 996
 997void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 998{
 999        struct ieee80211_local *local =
1000                container_of(work, struct ieee80211_local,
1001                             sched_scan_stopped_work);
1002
1003        mutex_lock(&local->mtx);
1004
1005        if (!rcu_access_pointer(local->sched_scan_sdata)) {
1006                mutex_unlock(&local->mtx);
1007                return;
1008        }
1009
1010        rcu_assign_pointer(local->sched_scan_sdata, NULL);
1011
1012        mutex_unlock(&local->mtx);
1013
1014        cfg80211_sched_scan_stopped(local->hw.wiphy);
1015}
1016
1017void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1018{
1019        struct ieee80211_local *local = hw_to_local(hw);
1020
1021        trace_api_sched_scan_stopped(local);
1022
1023        ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1024}
1025EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1026
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