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 * Copyright 2013-2014 Intel Mobile Communications GmbH 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 */ 15 16 #include <linux/if_arp.h> 17 #include <linux/etherdevice.h> 18 #include <linux/rtnetlink.h> 19 #include <linux/pm_qos.h> 20 #include <net/sch_generic.h> 21 #include <linux/slab.h> 22 #include <linux/export.h> 23 #include <net/mac80211.h> 24 25 #include "ieee80211_i.h" 26 #include "driver-ops.h" 27 #include "mesh.h" 28 29 #define IEEE80211_PROBE_DELAY (HZ / 33) 30 #define IEEE80211_CHANNEL_TIME (HZ / 33) 31 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9) 32 33 void ieee80211_rx_bss_put(struct ieee80211_local *local, 34 struct ieee80211_bss *bss) 35 { 36 if (!bss) 37 return; 38 cfg80211_put_bss(local->hw.wiphy, 39 container_of((void *)bss, struct cfg80211_bss, priv)); 40 } 41 42 static bool is_uapsd_supported(struct ieee802_11_elems *elems) 43 { 44 u8 qos_info; 45 46 if (elems->wmm_info && elems->wmm_info_len == 7 47 && elems->wmm_info[5] == 1) 48 qos_info = elems->wmm_info[6]; 49 else if (elems->wmm_param && elems->wmm_param_len == 24 50 && elems->wmm_param[5] == 1) 51 qos_info = elems->wmm_param[6]; 52 else 53 /* no valid wmm information or parameter element found */ 54 return false; 55 56 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD; 57 } 58 59 struct ieee80211_bss * 60 ieee80211_bss_info_update(struct ieee80211_local *local, 61 struct ieee80211_rx_status *rx_status, 62 struct ieee80211_mgmt *mgmt, size_t len, 63 struct ieee802_11_elems *elems, 64 struct ieee80211_channel *channel) 65 { 66 bool beacon = ieee80211_is_beacon(mgmt->frame_control); 67 struct cfg80211_bss *cbss; 68 struct ieee80211_bss *bss; 69 int clen, srlen; 70 enum nl80211_bss_scan_width scan_width; 71 s32 signal = 0; 72 73 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) 74 signal = rx_status->signal * 100; 75 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) 76 signal = (rx_status->signal * 100) / local->hw.max_signal; 77 78 scan_width = NL80211_BSS_CHAN_WIDTH_20; 79 if (rx_status->flag & RX_FLAG_5MHZ) 80 scan_width = NL80211_BSS_CHAN_WIDTH_5; 81 if (rx_status->flag & RX_FLAG_10MHZ) 82 scan_width = NL80211_BSS_CHAN_WIDTH_10; 83 84 cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel, 85 scan_width, mgmt, len, signal, 86 GFP_ATOMIC); 87 if (!cbss) 88 return NULL; 89 90 bss = (void *)cbss->priv; 91 92 if (beacon) 93 bss->device_ts_beacon = rx_status->device_timestamp; 94 else 95 bss->device_ts_presp = rx_status->device_timestamp; 96 97 if (elems->parse_error) { 98 if (beacon) 99 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; 100 else 101 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; 102 } else { 103 if (beacon) 104 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; 105 else 106 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; 107 } 108 109 /* save the ERP value so that it is available at association time */ 110 if (elems->erp_info && (!elems->parse_error || 111 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { 112 bss->erp_value = elems->erp_info[0]; 113 bss->has_erp_value = true; 114 if (!elems->parse_error) 115 bss->valid_data |= IEEE80211_BSS_VALID_ERP; 116 } 117 118 /* replace old supported rates if we get new values */ 119 if (!elems->parse_error || 120 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { 121 srlen = 0; 122 if (elems->supp_rates) { 123 clen = IEEE80211_MAX_SUPP_RATES; 124 if (clen > elems->supp_rates_len) 125 clen = elems->supp_rates_len; 126 memcpy(bss->supp_rates, elems->supp_rates, clen); 127 srlen += clen; 128 } 129 if (elems->ext_supp_rates) { 130 clen = IEEE80211_MAX_SUPP_RATES - srlen; 131 if (clen > elems->ext_supp_rates_len) 132 clen = elems->ext_supp_rates_len; 133 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, 134 clen); 135 srlen += clen; 136 } 137 if (srlen) { 138 bss->supp_rates_len = srlen; 139 if (!elems->parse_error) 140 bss->valid_data |= IEEE80211_BSS_VALID_RATES; 141 } 142 } 143 144 if (!elems->parse_error || 145 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { 146 bss->wmm_used = elems->wmm_param || elems->wmm_info; 147 bss->uapsd_supported = is_uapsd_supported(elems); 148 if (!elems->parse_error) 149 bss->valid_data |= IEEE80211_BSS_VALID_WMM; 150 } 151 152 if (beacon) { 153 struct ieee80211_supported_band *sband = 154 local->hw.wiphy->bands[rx_status->band]; 155 if (!(rx_status->flag & RX_FLAG_HT) && 156 !(rx_status->flag & RX_FLAG_VHT)) 157 bss->beacon_rate = 158 &sband->bitrates[rx_status->rate_idx]; 159 } 160 161 return bss; 162 } 163 164 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) 165 { 166 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); 167 struct ieee80211_sub_if_data *sdata1, *sdata2; 168 struct ieee80211_mgmt *mgmt = (void *)skb->data; 169 struct ieee80211_bss *bss; 170 u8 *elements; 171 struct ieee80211_channel *channel; 172 size_t baselen; 173 struct ieee802_11_elems elems; 174 175 if (skb->len < 24 || 176 (!ieee80211_is_probe_resp(mgmt->frame_control) && 177 !ieee80211_is_beacon(mgmt->frame_control))) 178 return; 179 180 sdata1 = rcu_dereference(local->scan_sdata); 181 sdata2 = rcu_dereference(local->sched_scan_sdata); 182 183 if (likely(!sdata1 && !sdata2)) 184 return; 185 186 if (ieee80211_is_probe_resp(mgmt->frame_control)) { 187 struct cfg80211_scan_request *scan_req; 188 struct cfg80211_sched_scan_request *sched_scan_req; 189 190 scan_req = rcu_dereference(local->scan_req); 191 sched_scan_req = rcu_dereference(local->sched_scan_req); 192 193 /* ignore ProbeResp to foreign address unless scanning 194 * with randomised address 195 */ 196 if (!(sdata1 && 197 (ether_addr_equal(mgmt->da, sdata1->vif.addr) || 198 scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) && 199 !(sdata2 && 200 (ether_addr_equal(mgmt->da, sdata2->vif.addr) || 201 sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR))) 202 return; 203 204 elements = mgmt->u.probe_resp.variable; 205 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 206 } else { 207 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 208 elements = mgmt->u.beacon.variable; 209 } 210 211 if (baselen > skb->len) 212 return; 213 214 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems); 215 216 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); 217 218 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 219 return; 220 221 bss = ieee80211_bss_info_update(local, rx_status, 222 mgmt, skb->len, &elems, 223 channel); 224 if (bss) 225 ieee80211_rx_bss_put(local, bss); 226 } 227 228 static void 229 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef, 230 enum nl80211_bss_scan_width scan_width) 231 { 232 memset(chandef, 0, sizeof(*chandef)); 233 switch (scan_width) { 234 case NL80211_BSS_CHAN_WIDTH_5: 235 chandef->width = NL80211_CHAN_WIDTH_5; 236 break; 237 case NL80211_BSS_CHAN_WIDTH_10: 238 chandef->width = NL80211_CHAN_WIDTH_10; 239 break; 240 default: 241 chandef->width = NL80211_CHAN_WIDTH_20_NOHT; 242 break; 243 } 244 } 245 246 /* return false if no more work */ 247 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 248 { 249 struct cfg80211_scan_request *req; 250 struct cfg80211_chan_def chandef; 251 u8 bands_used = 0; 252 int i, ielen, n_chans; 253 254 req = rcu_dereference_protected(local->scan_req, 255 lockdep_is_held(&local->mtx)); 256 257 if (test_bit(SCAN_HW_CANCELLED, &local->scanning)) 258 return false; 259 260 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) { 261 for (i = 0; i < req->n_channels; i++) { 262 local->hw_scan_req->req.channels[i] = req->channels[i]; 263 bands_used |= BIT(req->channels[i]->band); 264 } 265 266 n_chans = req->n_channels; 267 } else { 268 do { 269 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 270 return false; 271 272 n_chans = 0; 273 274 for (i = 0; i < req->n_channels; i++) { 275 if (req->channels[i]->band != 276 local->hw_scan_band) 277 continue; 278 local->hw_scan_req->req.channels[n_chans] = 279 req->channels[i]; 280 n_chans++; 281 bands_used |= BIT(req->channels[i]->band); 282 } 283 284 local->hw_scan_band++; 285 } while (!n_chans); 286 } 287 288 local->hw_scan_req->req.n_channels = n_chans; 289 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 290 291 ielen = ieee80211_build_preq_ies(local, 292 (u8 *)local->hw_scan_req->req.ie, 293 local->hw_scan_ies_bufsize, 294 &local->hw_scan_req->ies, 295 req->ie, req->ie_len, 296 bands_used, req->rates, &chandef); 297 local->hw_scan_req->req.ie_len = ielen; 298 local->hw_scan_req->req.no_cck = req->no_cck; 299 ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr); 300 ether_addr_copy(local->hw_scan_req->req.mac_addr_mask, 301 req->mac_addr_mask); 302 303 return true; 304 } 305 306 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 307 { 308 struct ieee80211_local *local = hw_to_local(hw); 309 bool hw_scan = local->ops->hw_scan; 310 bool was_scanning = local->scanning; 311 struct cfg80211_scan_request *scan_req; 312 struct ieee80211_sub_if_data *scan_sdata; 313 314 lockdep_assert_held(&local->mtx); 315 316 /* 317 * It's ok to abort a not-yet-running scan (that 318 * we have one at all will be verified by checking 319 * local->scan_req next), but not to complete it 320 * successfully. 321 */ 322 if (WARN_ON(!local->scanning && !aborted)) 323 aborted = true; 324 325 if (WARN_ON(!local->scan_req)) 326 return; 327 328 if (hw_scan && !aborted && 329 !(local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) && 330 ieee80211_prep_hw_scan(local)) { 331 int rc; 332 333 rc = drv_hw_scan(local, 334 rcu_dereference_protected(local->scan_sdata, 335 lockdep_is_held(&local->mtx)), 336 local->hw_scan_req); 337 338 if (rc == 0) 339 return; 340 } 341 342 kfree(local->hw_scan_req); 343 local->hw_scan_req = NULL; 344 345 scan_req = rcu_dereference_protected(local->scan_req, 346 lockdep_is_held(&local->mtx)); 347 348 if (scan_req != local->int_scan_req) 349 cfg80211_scan_done(scan_req, aborted); 350 RCU_INIT_POINTER(local->scan_req, NULL); 351 352 scan_sdata = rcu_dereference_protected(local->scan_sdata, 353 lockdep_is_held(&local->mtx)); 354 RCU_INIT_POINTER(local->scan_sdata, NULL); 355 356 local->scanning = 0; 357 local->scan_chandef.chan = NULL; 358 359 /* Set power back to normal operating levels. */ 360 ieee80211_hw_config(local, 0); 361 362 if (!hw_scan) { 363 ieee80211_configure_filter(local); 364 drv_sw_scan_complete(local, scan_sdata); 365 ieee80211_offchannel_return(local); 366 } 367 368 ieee80211_recalc_idle(local); 369 370 ieee80211_mlme_notify_scan_completed(local); 371 ieee80211_ibss_notify_scan_completed(local); 372 ieee80211_mesh_notify_scan_completed(local); 373 if (was_scanning) 374 ieee80211_start_next_roc(local); 375 } 376 377 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 378 { 379 struct ieee80211_local *local = hw_to_local(hw); 380 381 trace_api_scan_completed(local, aborted); 382 383 set_bit(SCAN_COMPLETED, &local->scanning); 384 if (aborted) 385 set_bit(SCAN_ABORTED, &local->scanning); 386 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 387 } 388 EXPORT_SYMBOL(ieee80211_scan_completed); 389 390 static int ieee80211_start_sw_scan(struct ieee80211_local *local, 391 struct ieee80211_sub_if_data *sdata) 392 { 393 /* Software scan is not supported in multi-channel cases */ 394 if (local->use_chanctx) 395 return -EOPNOTSUPP; 396 397 /* 398 * Hardware/driver doesn't support hw_scan, so use software 399 * scanning instead. First send a nullfunc frame with power save 400 * bit on so that AP will buffer the frames for us while we are not 401 * listening, then send probe requests to each channel and wait for 402 * the responses. After all channels are scanned, tune back to the 403 * original channel and send a nullfunc frame with power save bit 404 * off to trigger the AP to send us all the buffered frames. 405 * 406 * Note that while local->sw_scanning is true everything else but 407 * nullfunc frames and probe requests will be dropped in 408 * ieee80211_tx_h_check_assoc(). 409 */ 410 drv_sw_scan_start(local, sdata, local->scan_addr); 411 412 local->leave_oper_channel_time = jiffies; 413 local->next_scan_state = SCAN_DECISION; 414 local->scan_channel_idx = 0; 415 416 ieee80211_offchannel_stop_vifs(local); 417 418 /* ensure nullfunc is transmitted before leaving operating channel */ 419 ieee80211_flush_queues(local, NULL, false); 420 421 ieee80211_configure_filter(local); 422 423 /* We need to set power level at maximum rate for scanning. */ 424 ieee80211_hw_config(local, 0); 425 426 ieee80211_queue_delayed_work(&local->hw, 427 &local->scan_work, 0); 428 429 return 0; 430 } 431 432 static bool ieee80211_can_scan(struct ieee80211_local *local, 433 struct ieee80211_sub_if_data *sdata) 434 { 435 if (ieee80211_is_radar_required(local)) 436 return false; 437 438 if (!list_empty(&local->roc_list)) 439 return false; 440 441 if (sdata->vif.type == NL80211_IFTYPE_STATION && 442 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL) 443 return false; 444 445 return true; 446 } 447 448 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 449 { 450 lockdep_assert_held(&local->mtx); 451 452 if (!local->scan_req || local->scanning) 453 return; 454 455 if (!ieee80211_can_scan(local, 456 rcu_dereference_protected( 457 local->scan_sdata, 458 lockdep_is_held(&local->mtx)))) 459 return; 460 461 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 462 round_jiffies_relative(0)); 463 } 464 465 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 466 unsigned long *next_delay) 467 { 468 int i; 469 struct ieee80211_sub_if_data *sdata; 470 struct cfg80211_scan_request *scan_req; 471 enum ieee80211_band band = local->hw.conf.chandef.chan->band; 472 u32 tx_flags; 473 474 scan_req = rcu_dereference_protected(local->scan_req, 475 lockdep_is_held(&local->mtx)); 476 477 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 478 if (scan_req->no_cck) 479 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 480 481 sdata = rcu_dereference_protected(local->scan_sdata, 482 lockdep_is_held(&local->mtx)); 483 484 for (i = 0; i < scan_req->n_ssids; i++) 485 ieee80211_send_probe_req( 486 sdata, local->scan_addr, NULL, 487 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len, 488 scan_req->ie, scan_req->ie_len, 489 scan_req->rates[band], false, 490 tx_flags, local->hw.conf.chandef.chan, true); 491 492 /* 493 * After sending probe requests, wait for probe responses 494 * on the channel. 495 */ 496 *next_delay = IEEE80211_CHANNEL_TIME; 497 local->next_scan_state = SCAN_DECISION; 498 } 499 500 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 501 struct cfg80211_scan_request *req) 502 { 503 struct ieee80211_local *local = sdata->local; 504 int rc; 505 506 lockdep_assert_held(&local->mtx); 507 508 if (local->scan_req || ieee80211_is_radar_required(local)) 509 return -EBUSY; 510 511 if (!ieee80211_can_scan(local, sdata)) { 512 /* wait for the work to finish/time out */ 513 rcu_assign_pointer(local->scan_req, req); 514 rcu_assign_pointer(local->scan_sdata, sdata); 515 return 0; 516 } 517 518 if (local->ops->hw_scan) { 519 u8 *ies; 520 521 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len; 522 523 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) { 524 int i, n_bands = 0; 525 u8 bands_counted = 0; 526 527 for (i = 0; i < req->n_channels; i++) { 528 if (bands_counted & BIT(req->channels[i]->band)) 529 continue; 530 bands_counted |= BIT(req->channels[i]->band); 531 n_bands++; 532 } 533 534 local->hw_scan_ies_bufsize *= n_bands; 535 } 536 537 local->hw_scan_req = kmalloc( 538 sizeof(*local->hw_scan_req) + 539 req->n_channels * sizeof(req->channels[0]) + 540 local->hw_scan_ies_bufsize, GFP_KERNEL); 541 if (!local->hw_scan_req) 542 return -ENOMEM; 543 544 local->hw_scan_req->req.ssids = req->ssids; 545 local->hw_scan_req->req.n_ssids = req->n_ssids; 546 ies = (u8 *)local->hw_scan_req + 547 sizeof(*local->hw_scan_req) + 548 req->n_channels * sizeof(req->channels[0]); 549 local->hw_scan_req->req.ie = ies; 550 local->hw_scan_req->req.flags = req->flags; 551 552 local->hw_scan_band = 0; 553 554 /* 555 * After allocating local->hw_scan_req, we must 556 * go through until ieee80211_prep_hw_scan(), so 557 * anything that might be changed here and leave 558 * this function early must not go after this 559 * allocation. 560 */ 561 } 562 563 rcu_assign_pointer(local->scan_req, req); 564 rcu_assign_pointer(local->scan_sdata, sdata); 565 566 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR) 567 get_random_mask_addr(local->scan_addr, 568 req->mac_addr, 569 req->mac_addr_mask); 570 else 571 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN); 572 573 if (local->ops->hw_scan) { 574 __set_bit(SCAN_HW_SCANNING, &local->scanning); 575 } else if ((req->n_channels == 1) && 576 (req->channels[0] == local->_oper_chandef.chan)) { 577 /* 578 * If we are scanning only on the operating channel 579 * then we do not need to stop normal activities 580 */ 581 unsigned long next_delay; 582 583 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 584 585 ieee80211_recalc_idle(local); 586 587 /* Notify driver scan is starting, keep order of operations 588 * same as normal software scan, in case that matters. */ 589 drv_sw_scan_start(local, sdata, local->scan_addr); 590 591 ieee80211_configure_filter(local); /* accept probe-responses */ 592 593 /* We need to ensure power level is at max for scanning. */ 594 ieee80211_hw_config(local, 0); 595 596 if ((req->channels[0]->flags & 597 IEEE80211_CHAN_NO_IR) || 598 !req->n_ssids) { 599 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 600 } else { 601 ieee80211_scan_state_send_probe(local, &next_delay); 602 next_delay = IEEE80211_CHANNEL_TIME; 603 } 604 605 /* Now, just wait a bit and we are all done! */ 606 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 607 next_delay); 608 return 0; 609 } else { 610 /* Do normal software scan */ 611 __set_bit(SCAN_SW_SCANNING, &local->scanning); 612 } 613 614 ieee80211_recalc_idle(local); 615 616 if (local->ops->hw_scan) { 617 WARN_ON(!ieee80211_prep_hw_scan(local)); 618 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 619 } else { 620 rc = ieee80211_start_sw_scan(local, sdata); 621 } 622 623 if (rc) { 624 kfree(local->hw_scan_req); 625 local->hw_scan_req = NULL; 626 local->scanning = 0; 627 628 ieee80211_recalc_idle(local); 629 630 local->scan_req = NULL; 631 RCU_INIT_POINTER(local->scan_sdata, NULL); 632 } 633 634 return rc; 635 } 636 637 static unsigned long 638 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 639 { 640 /* 641 * TODO: channel switching also consumes quite some time, 642 * add that delay as well to get a better estimation 643 */ 644 if (chan->flags & IEEE80211_CHAN_NO_IR) 645 return IEEE80211_PASSIVE_CHANNEL_TIME; 646 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 647 } 648 649 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 650 unsigned long *next_delay) 651 { 652 bool associated = false; 653 bool tx_empty = true; 654 bool bad_latency; 655 struct ieee80211_sub_if_data *sdata; 656 struct ieee80211_channel *next_chan; 657 enum mac80211_scan_state next_scan_state; 658 struct cfg80211_scan_request *scan_req; 659 660 /* 661 * check if at least one STA interface is associated, 662 * check if at least one STA interface has pending tx frames 663 * and grab the lowest used beacon interval 664 */ 665 mutex_lock(&local->iflist_mtx); 666 list_for_each_entry(sdata, &local->interfaces, list) { 667 if (!ieee80211_sdata_running(sdata)) 668 continue; 669 670 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 671 if (sdata->u.mgd.associated) { 672 associated = true; 673 674 if (!qdisc_all_tx_empty(sdata->dev)) { 675 tx_empty = false; 676 break; 677 } 678 } 679 } 680 } 681 mutex_unlock(&local->iflist_mtx); 682 683 scan_req = rcu_dereference_protected(local->scan_req, 684 lockdep_is_held(&local->mtx)); 685 686 next_chan = scan_req->channels[local->scan_channel_idx]; 687 688 /* 689 * we're currently scanning a different channel, let's 690 * see if we can scan another channel without interfering 691 * with the current traffic situation. 692 * 693 * Keep good latency, do not stay off-channel more than 125 ms. 694 */ 695 696 bad_latency = time_after(jiffies + 697 ieee80211_scan_get_channel_time(next_chan), 698 local->leave_oper_channel_time + HZ / 8); 699 700 if (associated && !tx_empty) { 701 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 702 next_scan_state = SCAN_ABORT; 703 else 704 next_scan_state = SCAN_SUSPEND; 705 } else if (associated && bad_latency) { 706 next_scan_state = SCAN_SUSPEND; 707 } else { 708 next_scan_state = SCAN_SET_CHANNEL; 709 } 710 711 local->next_scan_state = next_scan_state; 712 713 *next_delay = 0; 714 } 715 716 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 717 unsigned long *next_delay) 718 { 719 int skip; 720 struct ieee80211_channel *chan; 721 enum nl80211_bss_scan_width oper_scan_width; 722 struct cfg80211_scan_request *scan_req; 723 724 scan_req = rcu_dereference_protected(local->scan_req, 725 lockdep_is_held(&local->mtx)); 726 727 skip = 0; 728 chan = scan_req->channels[local->scan_channel_idx]; 729 730 local->scan_chandef.chan = chan; 731 local->scan_chandef.center_freq1 = chan->center_freq; 732 local->scan_chandef.center_freq2 = 0; 733 switch (scan_req->scan_width) { 734 case NL80211_BSS_CHAN_WIDTH_5: 735 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 736 break; 737 case NL80211_BSS_CHAN_WIDTH_10: 738 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 739 break; 740 case NL80211_BSS_CHAN_WIDTH_20: 741 /* If scanning on oper channel, use whatever channel-type 742 * is currently in use. 743 */ 744 oper_scan_width = cfg80211_chandef_to_scan_width( 745 &local->_oper_chandef); 746 if (chan == local->_oper_chandef.chan && 747 oper_scan_width == scan_req->scan_width) 748 local->scan_chandef = local->_oper_chandef; 749 else 750 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 751 break; 752 } 753 754 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 755 skip = 1; 756 757 /* advance state machine to next channel/band */ 758 local->scan_channel_idx++; 759 760 if (skip) { 761 /* if we skip this channel return to the decision state */ 762 local->next_scan_state = SCAN_DECISION; 763 return; 764 } 765 766 /* 767 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 768 * (which unfortunately doesn't say _why_ step a) is done, 769 * but it waits for the probe delay or until a frame is 770 * received - and the received frame would update the NAV). 771 * For now, we do not support waiting until a frame is 772 * received. 773 * 774 * In any case, it is not necessary for a passive scan. 775 */ 776 if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) { 777 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 778 local->next_scan_state = SCAN_DECISION; 779 return; 780 } 781 782 /* active scan, send probes */ 783 *next_delay = IEEE80211_PROBE_DELAY; 784 local->next_scan_state = SCAN_SEND_PROBE; 785 } 786 787 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 788 unsigned long *next_delay) 789 { 790 /* switch back to the operating channel */ 791 local->scan_chandef.chan = NULL; 792 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 793 794 /* disable PS */ 795 ieee80211_offchannel_return(local); 796 797 *next_delay = HZ / 5; 798 /* afterwards, resume scan & go to next channel */ 799 local->next_scan_state = SCAN_RESUME; 800 } 801 802 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 803 unsigned long *next_delay) 804 { 805 ieee80211_offchannel_stop_vifs(local); 806 807 if (local->ops->flush) { 808 ieee80211_flush_queues(local, NULL, false); 809 *next_delay = 0; 810 } else 811 *next_delay = HZ / 10; 812 813 /* remember when we left the operating channel */ 814 local->leave_oper_channel_time = jiffies; 815 816 /* advance to the next channel to be scanned */ 817 local->next_scan_state = SCAN_SET_CHANNEL; 818 } 819 820 void ieee80211_scan_work(struct work_struct *work) 821 { 822 struct ieee80211_local *local = 823 container_of(work, struct ieee80211_local, scan_work.work); 824 struct ieee80211_sub_if_data *sdata; 825 struct cfg80211_scan_request *scan_req; 826 unsigned long next_delay = 0; 827 bool aborted; 828 829 mutex_lock(&local->mtx); 830 831 if (!ieee80211_can_run_worker(local)) { 832 aborted = true; 833 goto out_complete; 834 } 835 836 sdata = rcu_dereference_protected(local->scan_sdata, 837 lockdep_is_held(&local->mtx)); 838 scan_req = rcu_dereference_protected(local->scan_req, 839 lockdep_is_held(&local->mtx)); 840 841 /* When scanning on-channel, the first-callback means completed. */ 842 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 843 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 844 goto out_complete; 845 } 846 847 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 848 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 849 goto out_complete; 850 } 851 852 if (!sdata || !scan_req) 853 goto out; 854 855 if (!local->scanning) { 856 int rc; 857 858 RCU_INIT_POINTER(local->scan_req, NULL); 859 RCU_INIT_POINTER(local->scan_sdata, NULL); 860 861 rc = __ieee80211_start_scan(sdata, scan_req); 862 if (rc) { 863 /* need to complete scan in cfg80211 */ 864 rcu_assign_pointer(local->scan_req, scan_req); 865 aborted = true; 866 goto out_complete; 867 } else 868 goto out; 869 } 870 871 /* 872 * as long as no delay is required advance immediately 873 * without scheduling a new work 874 */ 875 do { 876 if (!ieee80211_sdata_running(sdata)) { 877 aborted = true; 878 goto out_complete; 879 } 880 881 switch (local->next_scan_state) { 882 case SCAN_DECISION: 883 /* if no more bands/channels left, complete scan */ 884 if (local->scan_channel_idx >= scan_req->n_channels) { 885 aborted = false; 886 goto out_complete; 887 } 888 ieee80211_scan_state_decision(local, &next_delay); 889 break; 890 case SCAN_SET_CHANNEL: 891 ieee80211_scan_state_set_channel(local, &next_delay); 892 break; 893 case SCAN_SEND_PROBE: 894 ieee80211_scan_state_send_probe(local, &next_delay); 895 break; 896 case SCAN_SUSPEND: 897 ieee80211_scan_state_suspend(local, &next_delay); 898 break; 899 case SCAN_RESUME: 900 ieee80211_scan_state_resume(local, &next_delay); 901 break; 902 case SCAN_ABORT: 903 aborted = true; 904 goto out_complete; 905 } 906 } while (next_delay == 0); 907 908 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 909 goto out; 910 911 out_complete: 912 __ieee80211_scan_completed(&local->hw, aborted); 913 out: 914 mutex_unlock(&local->mtx); 915 } 916 917 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 918 struct cfg80211_scan_request *req) 919 { 920 int res; 921 922 mutex_lock(&sdata->local->mtx); 923 res = __ieee80211_start_scan(sdata, req); 924 mutex_unlock(&sdata->local->mtx); 925 926 return res; 927 } 928 929 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 930 const u8 *ssid, u8 ssid_len, 931 struct ieee80211_channel *chan, 932 enum nl80211_bss_scan_width scan_width) 933 { 934 struct ieee80211_local *local = sdata->local; 935 int ret = -EBUSY; 936 enum ieee80211_band band; 937 938 mutex_lock(&local->mtx); 939 940 /* busy scanning */ 941 if (local->scan_req) 942 goto unlock; 943 944 /* fill internal scan request */ 945 if (!chan) { 946 int i, max_n; 947 int n_ch = 0; 948 949 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 950 if (!local->hw.wiphy->bands[band]) 951 continue; 952 953 max_n = local->hw.wiphy->bands[band]->n_channels; 954 for (i = 0; i < max_n; i++) { 955 struct ieee80211_channel *tmp_ch = 956 &local->hw.wiphy->bands[band]->channels[i]; 957 958 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR | 959 IEEE80211_CHAN_DISABLED)) 960 continue; 961 962 local->int_scan_req->channels[n_ch] = tmp_ch; 963 n_ch++; 964 } 965 } 966 967 if (WARN_ON_ONCE(n_ch == 0)) 968 goto unlock; 969 970 local->int_scan_req->n_channels = n_ch; 971 } else { 972 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR | 973 IEEE80211_CHAN_DISABLED))) 974 goto unlock; 975 976 local->int_scan_req->channels[0] = chan; 977 local->int_scan_req->n_channels = 1; 978 } 979 980 local->int_scan_req->ssids = &local->scan_ssid; 981 local->int_scan_req->n_ssids = 1; 982 local->int_scan_req->scan_width = scan_width; 983 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 984 local->int_scan_req->ssids[0].ssid_len = ssid_len; 985 986 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 987 unlock: 988 mutex_unlock(&local->mtx); 989 return ret; 990 } 991 992 /* 993 * Only call this function when a scan can't be queued -- under RTNL. 994 */ 995 void ieee80211_scan_cancel(struct ieee80211_local *local) 996 { 997 /* 998 * We are canceling software scan, or deferred scan that was not 999 * yet really started (see __ieee80211_start_scan ). 1000 * 1001 * Regarding hardware scan: 1002 * - we can not call __ieee80211_scan_completed() as when 1003 * SCAN_HW_SCANNING bit is set this function change 1004 * local->hw_scan_req to operate on 5G band, what race with 1005 * driver which can use local->hw_scan_req 1006 * 1007 * - we can not cancel scan_work since driver can schedule it 1008 * by ieee80211_scan_completed(..., true) to finish scan 1009 * 1010 * Hence we only call the cancel_hw_scan() callback, but the low-level 1011 * driver is still responsible for calling ieee80211_scan_completed() 1012 * after the scan was completed/aborted. 1013 */ 1014 1015 mutex_lock(&local->mtx); 1016 if (!local->scan_req) 1017 goto out; 1018 1019 /* 1020 * We have a scan running and the driver already reported completion, 1021 * but the worker hasn't run yet or is stuck on the mutex - mark it as 1022 * cancelled. 1023 */ 1024 if (test_bit(SCAN_HW_SCANNING, &local->scanning) && 1025 test_bit(SCAN_COMPLETED, &local->scanning)) { 1026 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1027 goto out; 1028 } 1029 1030 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 1031 /* 1032 * Make sure that __ieee80211_scan_completed doesn't trigger a 1033 * scan on another band. 1034 */ 1035 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1036 if (local->ops->cancel_hw_scan) 1037 drv_cancel_hw_scan(local, 1038 rcu_dereference_protected(local->scan_sdata, 1039 lockdep_is_held(&local->mtx))); 1040 goto out; 1041 } 1042 1043 /* 1044 * If the work is currently running, it must be blocked on 1045 * the mutex, but we'll set scan_sdata = NULL and it'll 1046 * simply exit once it acquires the mutex. 1047 */ 1048 cancel_delayed_work(&local->scan_work); 1049 /* and clean up */ 1050 __ieee80211_scan_completed(&local->hw, true); 1051 out: 1052 mutex_unlock(&local->mtx); 1053 } 1054 1055 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1056 struct cfg80211_sched_scan_request *req) 1057 { 1058 struct ieee80211_local *local = sdata->local; 1059 struct ieee80211_scan_ies sched_scan_ies = {}; 1060 struct cfg80211_chan_def chandef; 1061 int ret, i, iebufsz, num_bands = 0; 1062 u32 rate_masks[IEEE80211_NUM_BANDS] = {}; 1063 u8 bands_used = 0; 1064 u8 *ie; 1065 size_t len; 1066 1067 iebufsz = local->scan_ies_len + req->ie_len; 1068 1069 lockdep_assert_held(&local->mtx); 1070 1071 if (!local->ops->sched_scan_start) 1072 return -ENOTSUPP; 1073 1074 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 1075 if (local->hw.wiphy->bands[i]) { 1076 bands_used |= BIT(i); 1077 rate_masks[i] = (u32) -1; 1078 num_bands++; 1079 } 1080 } 1081 1082 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL); 1083 if (!ie) { 1084 ret = -ENOMEM; 1085 goto out; 1086 } 1087 1088 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 1089 1090 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz, 1091 &sched_scan_ies, req->ie, 1092 req->ie_len, bands_used, 1093 rate_masks, &chandef); 1094 1095 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1096 if (ret == 0) { 1097 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1098 rcu_assign_pointer(local->sched_scan_req, req); 1099 } 1100 1101 kfree(ie); 1102 1103 out: 1104 if (ret) { 1105 /* Clean in case of failure after HW restart or upon resume. */ 1106 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1107 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1108 } 1109 1110 return ret; 1111 } 1112 1113 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1114 struct cfg80211_sched_scan_request *req) 1115 { 1116 struct ieee80211_local *local = sdata->local; 1117 int ret; 1118 1119 mutex_lock(&local->mtx); 1120 1121 if (rcu_access_pointer(local->sched_scan_sdata)) { 1122 mutex_unlock(&local->mtx); 1123 return -EBUSY; 1124 } 1125 1126 ret = __ieee80211_request_sched_scan_start(sdata, req); 1127 1128 mutex_unlock(&local->mtx); 1129 return ret; 1130 } 1131 1132 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 1133 { 1134 struct ieee80211_local *local = sdata->local; 1135 int ret = 0; 1136 1137 mutex_lock(&local->mtx); 1138 1139 if (!local->ops->sched_scan_stop) { 1140 ret = -ENOTSUPP; 1141 goto out; 1142 } 1143 1144 /* We don't want to restart sched scan anymore. */ 1145 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1146 1147 if (rcu_access_pointer(local->sched_scan_sdata)) { 1148 ret = drv_sched_scan_stop(local, sdata); 1149 if (!ret) 1150 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1151 } 1152 out: 1153 mutex_unlock(&local->mtx); 1154 1155 return ret; 1156 } 1157 1158 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1159 { 1160 struct ieee80211_local *local = hw_to_local(hw); 1161 1162 trace_api_sched_scan_results(local); 1163 1164 cfg80211_sched_scan_results(hw->wiphy); 1165 } 1166 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1167 1168 void ieee80211_sched_scan_end(struct ieee80211_local *local) 1169 { 1170 mutex_lock(&local->mtx); 1171 1172 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1173 mutex_unlock(&local->mtx); 1174 return; 1175 } 1176 1177 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1178 1179 /* If sched scan was aborted by the driver. */ 1180 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1181 1182 mutex_unlock(&local->mtx); 1183 1184 cfg80211_sched_scan_stopped(local->hw.wiphy); 1185 } 1186 1187 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1188 { 1189 struct ieee80211_local *local = 1190 container_of(work, struct ieee80211_local, 1191 sched_scan_stopped_work); 1192 1193 ieee80211_sched_scan_end(local); 1194 } 1195 1196 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1197 { 1198 struct ieee80211_local *local = hw_to_local(hw); 1199 1200 trace_api_sched_scan_stopped(local); 1201 1202 schedule_work(&local->sched_scan_stopped_work); 1203 } 1204 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1205