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 2013-2015 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 <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 / 9) 31 32 void ieee80211_rx_bss_put(struct ieee80211_local *local, 33 struct ieee80211_bss *bss) 34 { 35 if (!bss) 36 return; 37 cfg80211_put_bss(local->hw.wiphy, 38 container_of((void *)bss, struct cfg80211_bss, priv)); 39 } 40 41 static bool is_uapsd_supported(struct ieee802_11_elems *elems) 42 { 43 u8 qos_info; 44 45 if (elems->wmm_info && elems->wmm_info_len == 7 46 && elems->wmm_info[5] == 1) 47 qos_info = elems->wmm_info[6]; 48 else if (elems->wmm_param && elems->wmm_param_len == 24 49 && elems->wmm_param[5] == 1) 50 qos_info = elems->wmm_param[6]; 51 else 52 /* no valid wmm information or parameter element found */ 53 return false; 54 55 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD; 56 } 57 58 struct ieee80211_bss * 59 ieee80211_bss_info_update(struct ieee80211_local *local, 60 struct ieee80211_rx_status *rx_status, 61 struct ieee80211_mgmt *mgmt, size_t len, 62 struct ieee802_11_elems *elems, 63 struct ieee80211_channel *channel) 64 { 65 bool beacon = ieee80211_is_beacon(mgmt->frame_control); 66 struct cfg80211_bss *cbss; 67 struct ieee80211_bss *bss; 68 int clen, srlen; 69 struct cfg80211_inform_bss bss_meta = {}; 70 bool signal_valid; 71 72 if (ieee80211_hw_check(&local->hw, SIGNAL_DBM)) 73 bss_meta.signal = rx_status->signal * 100; 74 else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC)) 75 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal; 76 77 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20; 78 if (rx_status->flag & RX_FLAG_5MHZ) 79 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5; 80 if (rx_status->flag & RX_FLAG_10MHZ) 81 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10; 82 83 bss_meta.chan = channel; 84 cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta, 85 mgmt, len, GFP_ATOMIC); 86 if (!cbss) 87 return NULL; 88 /* In case the signal is invalid update the status */ 89 signal_valid = abs(channel->center_freq - cbss->channel->center_freq) 90 <= local->hw.wiphy->max_adj_channel_rssi_comp; 91 if (!signal_valid) 92 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL; 93 94 bss = (void *)cbss->priv; 95 96 if (beacon) 97 bss->device_ts_beacon = rx_status->device_timestamp; 98 else 99 bss->device_ts_presp = rx_status->device_timestamp; 100 101 if (elems->parse_error) { 102 if (beacon) 103 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; 104 else 105 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; 106 } else { 107 if (beacon) 108 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; 109 else 110 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; 111 } 112 113 /* save the ERP value so that it is available at association time */ 114 if (elems->erp_info && (!elems->parse_error || 115 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { 116 bss->erp_value = elems->erp_info[0]; 117 bss->has_erp_value = true; 118 if (!elems->parse_error) 119 bss->valid_data |= IEEE80211_BSS_VALID_ERP; 120 } 121 122 /* replace old supported rates if we get new values */ 123 if (!elems->parse_error || 124 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { 125 srlen = 0; 126 if (elems->supp_rates) { 127 clen = IEEE80211_MAX_SUPP_RATES; 128 if (clen > elems->supp_rates_len) 129 clen = elems->supp_rates_len; 130 memcpy(bss->supp_rates, elems->supp_rates, clen); 131 srlen += clen; 132 } 133 if (elems->ext_supp_rates) { 134 clen = IEEE80211_MAX_SUPP_RATES - srlen; 135 if (clen > elems->ext_supp_rates_len) 136 clen = elems->ext_supp_rates_len; 137 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, 138 clen); 139 srlen += clen; 140 } 141 if (srlen) { 142 bss->supp_rates_len = srlen; 143 if (!elems->parse_error) 144 bss->valid_data |= IEEE80211_BSS_VALID_RATES; 145 } 146 } 147 148 if (!elems->parse_error || 149 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { 150 bss->wmm_used = elems->wmm_param || elems->wmm_info; 151 bss->uapsd_supported = is_uapsd_supported(elems); 152 if (!elems->parse_error) 153 bss->valid_data |= IEEE80211_BSS_VALID_WMM; 154 } 155 156 if (beacon) { 157 struct ieee80211_supported_band *sband = 158 local->hw.wiphy->bands[rx_status->band]; 159 if (!(rx_status->flag & RX_FLAG_HT) && 160 !(rx_status->flag & RX_FLAG_VHT)) 161 bss->beacon_rate = 162 &sband->bitrates[rx_status->rate_idx]; 163 } 164 165 return bss; 166 } 167 168 void 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 struct ieee802_11_elems elems; 178 179 if (skb->len < 24 || 180 (!ieee80211_is_probe_resp(mgmt->frame_control) && 181 !ieee80211_is_beacon(mgmt->frame_control))) 182 return; 183 184 sdata1 = rcu_dereference(local->scan_sdata); 185 sdata2 = rcu_dereference(local->sched_scan_sdata); 186 187 if (likely(!sdata1 && !sdata2)) 188 return; 189 190 if (ieee80211_is_probe_resp(mgmt->frame_control)) { 191 struct cfg80211_scan_request *scan_req; 192 struct cfg80211_sched_scan_request *sched_scan_req; 193 194 scan_req = rcu_dereference(local->scan_req); 195 sched_scan_req = rcu_dereference(local->sched_scan_req); 196 197 /* ignore ProbeResp to foreign address unless scanning 198 * with randomised address 199 */ 200 if (!(sdata1 && 201 (ether_addr_equal(mgmt->da, sdata1->vif.addr) || 202 scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) && 203 !(sdata2 && 204 (ether_addr_equal(mgmt->da, sdata2->vif.addr) || 205 sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR))) 206 return; 207 208 elements = mgmt->u.probe_resp.variable; 209 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 210 } else { 211 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 212 elements = mgmt->u.beacon.variable; 213 } 214 215 if (baselen > skb->len) 216 return; 217 218 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems); 219 220 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); 221 222 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 223 return; 224 225 bss = ieee80211_bss_info_update(local, rx_status, 226 mgmt, skb->len, &elems, 227 channel); 228 if (bss) 229 ieee80211_rx_bss_put(local, bss); 230 } 231 232 static void 233 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef, 234 enum nl80211_bss_scan_width scan_width) 235 { 236 memset(chandef, 0, sizeof(*chandef)); 237 switch (scan_width) { 238 case NL80211_BSS_CHAN_WIDTH_5: 239 chandef->width = NL80211_CHAN_WIDTH_5; 240 break; 241 case NL80211_BSS_CHAN_WIDTH_10: 242 chandef->width = NL80211_CHAN_WIDTH_10; 243 break; 244 default: 245 chandef->width = NL80211_CHAN_WIDTH_20_NOHT; 246 break; 247 } 248 } 249 250 /* return false if no more work */ 251 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 252 { 253 struct cfg80211_scan_request *req; 254 struct cfg80211_chan_def chandef; 255 u8 bands_used = 0; 256 int i, ielen, n_chans; 257 258 req = rcu_dereference_protected(local->scan_req, 259 lockdep_is_held(&local->mtx)); 260 261 if (test_bit(SCAN_HW_CANCELLED, &local->scanning)) 262 return false; 263 264 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { 265 for (i = 0; i < req->n_channels; i++) { 266 local->hw_scan_req->req.channels[i] = req->channels[i]; 267 bands_used |= BIT(req->channels[i]->band); 268 } 269 270 n_chans = req->n_channels; 271 } else { 272 do { 273 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 274 return false; 275 276 n_chans = 0; 277 278 for (i = 0; i < req->n_channels; i++) { 279 if (req->channels[i]->band != 280 local->hw_scan_band) 281 continue; 282 local->hw_scan_req->req.channels[n_chans] = 283 req->channels[i]; 284 n_chans++; 285 bands_used |= BIT(req->channels[i]->band); 286 } 287 288 local->hw_scan_band++; 289 } while (!n_chans); 290 } 291 292 local->hw_scan_req->req.n_channels = n_chans; 293 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 294 295 ielen = ieee80211_build_preq_ies(local, 296 (u8 *)local->hw_scan_req->req.ie, 297 local->hw_scan_ies_bufsize, 298 &local->hw_scan_req->ies, 299 req->ie, req->ie_len, 300 bands_used, req->rates, &chandef); 301 local->hw_scan_req->req.ie_len = ielen; 302 local->hw_scan_req->req.no_cck = req->no_cck; 303 ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr); 304 ether_addr_copy(local->hw_scan_req->req.mac_addr_mask, 305 req->mac_addr_mask); 306 307 return true; 308 } 309 310 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 311 { 312 struct ieee80211_local *local = hw_to_local(hw); 313 bool hw_scan = local->ops->hw_scan; 314 bool was_scanning = local->scanning; 315 struct cfg80211_scan_request *scan_req; 316 struct ieee80211_sub_if_data *scan_sdata; 317 struct ieee80211_sub_if_data *sdata; 318 319 lockdep_assert_held(&local->mtx); 320 321 /* 322 * It's ok to abort a not-yet-running scan (that 323 * we have one at all will be verified by checking 324 * local->scan_req next), but not to complete it 325 * successfully. 326 */ 327 if (WARN_ON(!local->scanning && !aborted)) 328 aborted = true; 329 330 if (WARN_ON(!local->scan_req)) 331 return; 332 333 if (hw_scan && !aborted && 334 !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) && 335 ieee80211_prep_hw_scan(local)) { 336 int rc; 337 338 rc = drv_hw_scan(local, 339 rcu_dereference_protected(local->scan_sdata, 340 lockdep_is_held(&local->mtx)), 341 local->hw_scan_req); 342 343 if (rc == 0) 344 return; 345 } 346 347 kfree(local->hw_scan_req); 348 local->hw_scan_req = NULL; 349 350 scan_req = rcu_dereference_protected(local->scan_req, 351 lockdep_is_held(&local->mtx)); 352 353 if (scan_req != local->int_scan_req) 354 cfg80211_scan_done(scan_req, aborted); 355 RCU_INIT_POINTER(local->scan_req, NULL); 356 357 scan_sdata = rcu_dereference_protected(local->scan_sdata, 358 lockdep_is_held(&local->mtx)); 359 RCU_INIT_POINTER(local->scan_sdata, NULL); 360 361 local->scanning = 0; 362 local->scan_chandef.chan = NULL; 363 364 /* Set power back to normal operating levels. */ 365 ieee80211_hw_config(local, 0); 366 367 if (!hw_scan) { 368 ieee80211_configure_filter(local); 369 drv_sw_scan_complete(local, scan_sdata); 370 ieee80211_offchannel_return(local); 371 } 372 373 ieee80211_recalc_idle(local); 374 375 ieee80211_mlme_notify_scan_completed(local); 376 ieee80211_ibss_notify_scan_completed(local); 377 378 /* Requeue all the work that might have been ignored while 379 * the scan was in progress; if there was none this will 380 * just be a no-op for the particular interface. 381 */ 382 list_for_each_entry_rcu(sdata, &local->interfaces, list) { 383 if (ieee80211_sdata_running(sdata)) 384 ieee80211_queue_work(&sdata->local->hw, &sdata->work); 385 } 386 387 if (was_scanning) 388 ieee80211_start_next_roc(local); 389 } 390 391 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 392 { 393 struct ieee80211_local *local = hw_to_local(hw); 394 395 trace_api_scan_completed(local, aborted); 396 397 set_bit(SCAN_COMPLETED, &local->scanning); 398 if (aborted) 399 set_bit(SCAN_ABORTED, &local->scanning); 400 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 401 } 402 EXPORT_SYMBOL(ieee80211_scan_completed); 403 404 static int ieee80211_start_sw_scan(struct ieee80211_local *local, 405 struct ieee80211_sub_if_data *sdata) 406 { 407 /* Software scan is not supported in multi-channel cases */ 408 if (local->use_chanctx) 409 return -EOPNOTSUPP; 410 411 /* 412 * Hardware/driver doesn't support hw_scan, so use software 413 * scanning instead. First send a nullfunc frame with power save 414 * bit on so that AP will buffer the frames for us while we are not 415 * listening, then send probe requests to each channel and wait for 416 * the responses. After all channels are scanned, tune back to the 417 * original channel and send a nullfunc frame with power save bit 418 * off to trigger the AP to send us all the buffered frames. 419 * 420 * Note that while local->sw_scanning is true everything else but 421 * nullfunc frames and probe requests will be dropped in 422 * ieee80211_tx_h_check_assoc(). 423 */ 424 drv_sw_scan_start(local, sdata, local->scan_addr); 425 426 local->leave_oper_channel_time = jiffies; 427 local->next_scan_state = SCAN_DECISION; 428 local->scan_channel_idx = 0; 429 430 ieee80211_offchannel_stop_vifs(local); 431 432 /* ensure nullfunc is transmitted before leaving operating channel */ 433 ieee80211_flush_queues(local, NULL, false); 434 435 ieee80211_configure_filter(local); 436 437 /* We need to set power level at maximum rate for scanning. */ 438 ieee80211_hw_config(local, 0); 439 440 ieee80211_queue_delayed_work(&local->hw, 441 &local->scan_work, 0); 442 443 return 0; 444 } 445 446 static bool ieee80211_can_scan(struct ieee80211_local *local, 447 struct ieee80211_sub_if_data *sdata) 448 { 449 if (ieee80211_is_radar_required(local)) 450 return false; 451 452 if (!list_empty(&local->roc_list)) 453 return false; 454 455 if (sdata->vif.type == NL80211_IFTYPE_STATION && 456 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL) 457 return false; 458 459 return true; 460 } 461 462 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 463 { 464 lockdep_assert_held(&local->mtx); 465 466 if (!local->scan_req || local->scanning) 467 return; 468 469 if (!ieee80211_can_scan(local, 470 rcu_dereference_protected( 471 local->scan_sdata, 472 lockdep_is_held(&local->mtx)))) 473 return; 474 475 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 476 round_jiffies_relative(0)); 477 } 478 479 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 480 unsigned long *next_delay) 481 { 482 int i; 483 struct ieee80211_sub_if_data *sdata; 484 struct cfg80211_scan_request *scan_req; 485 enum ieee80211_band band = local->hw.conf.chandef.chan->band; 486 u32 tx_flags; 487 488 scan_req = rcu_dereference_protected(local->scan_req, 489 lockdep_is_held(&local->mtx)); 490 491 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 492 if (scan_req->no_cck) 493 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 494 495 sdata = rcu_dereference_protected(local->scan_sdata, 496 lockdep_is_held(&local->mtx)); 497 498 for (i = 0; i < scan_req->n_ssids; i++) 499 ieee80211_send_probe_req( 500 sdata, local->scan_addr, NULL, 501 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len, 502 scan_req->ie, scan_req->ie_len, 503 scan_req->rates[band], false, 504 tx_flags, local->hw.conf.chandef.chan, true); 505 506 /* 507 * After sending probe requests, wait for probe responses 508 * on the channel. 509 */ 510 *next_delay = IEEE80211_CHANNEL_TIME; 511 local->next_scan_state = SCAN_DECISION; 512 } 513 514 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 515 struct cfg80211_scan_request *req) 516 { 517 struct ieee80211_local *local = sdata->local; 518 int rc; 519 520 lockdep_assert_held(&local->mtx); 521 522 if (local->scan_req || ieee80211_is_radar_required(local)) 523 return -EBUSY; 524 525 if (!ieee80211_can_scan(local, sdata)) { 526 /* wait for the work to finish/time out */ 527 rcu_assign_pointer(local->scan_req, req); 528 rcu_assign_pointer(local->scan_sdata, sdata); 529 return 0; 530 } 531 532 if (local->ops->hw_scan) { 533 u8 *ies; 534 535 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len; 536 537 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { 538 int i, n_bands = 0; 539 u8 bands_counted = 0; 540 541 for (i = 0; i < req->n_channels; i++) { 542 if (bands_counted & BIT(req->channels[i]->band)) 543 continue; 544 bands_counted |= BIT(req->channels[i]->band); 545 n_bands++; 546 } 547 548 local->hw_scan_ies_bufsize *= n_bands; 549 } 550 551 local->hw_scan_req = kmalloc( 552 sizeof(*local->hw_scan_req) + 553 req->n_channels * sizeof(req->channels[0]) + 554 local->hw_scan_ies_bufsize, GFP_KERNEL); 555 if (!local->hw_scan_req) 556 return -ENOMEM; 557 558 local->hw_scan_req->req.ssids = req->ssids; 559 local->hw_scan_req->req.n_ssids = req->n_ssids; 560 ies = (u8 *)local->hw_scan_req + 561 sizeof(*local->hw_scan_req) + 562 req->n_channels * sizeof(req->channels[0]); 563 local->hw_scan_req->req.ie = ies; 564 local->hw_scan_req->req.flags = req->flags; 565 566 local->hw_scan_band = 0; 567 568 /* 569 * After allocating local->hw_scan_req, we must 570 * go through until ieee80211_prep_hw_scan(), so 571 * anything that might be changed here and leave 572 * this function early must not go after this 573 * allocation. 574 */ 575 } 576 577 rcu_assign_pointer(local->scan_req, req); 578 rcu_assign_pointer(local->scan_sdata, sdata); 579 580 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR) 581 get_random_mask_addr(local->scan_addr, 582 req->mac_addr, 583 req->mac_addr_mask); 584 else 585 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN); 586 587 if (local->ops->hw_scan) { 588 __set_bit(SCAN_HW_SCANNING, &local->scanning); 589 } else if ((req->n_channels == 1) && 590 (req->channels[0] == local->_oper_chandef.chan)) { 591 /* 592 * If we are scanning only on the operating channel 593 * then we do not need to stop normal activities 594 */ 595 unsigned long next_delay; 596 597 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 598 599 ieee80211_recalc_idle(local); 600 601 /* Notify driver scan is starting, keep order of operations 602 * same as normal software scan, in case that matters. */ 603 drv_sw_scan_start(local, sdata, local->scan_addr); 604 605 ieee80211_configure_filter(local); /* accept probe-responses */ 606 607 /* We need to ensure power level is at max for scanning. */ 608 ieee80211_hw_config(local, 0); 609 610 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR | 611 IEEE80211_CHAN_RADAR)) || 612 !req->n_ssids) { 613 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 614 } else { 615 ieee80211_scan_state_send_probe(local, &next_delay); 616 next_delay = IEEE80211_CHANNEL_TIME; 617 } 618 619 /* Now, just wait a bit and we are all done! */ 620 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 621 next_delay); 622 return 0; 623 } else { 624 /* Do normal software scan */ 625 __set_bit(SCAN_SW_SCANNING, &local->scanning); 626 } 627 628 ieee80211_recalc_idle(local); 629 630 if (local->ops->hw_scan) { 631 WARN_ON(!ieee80211_prep_hw_scan(local)); 632 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 633 } else { 634 rc = ieee80211_start_sw_scan(local, sdata); 635 } 636 637 if (rc) { 638 kfree(local->hw_scan_req); 639 local->hw_scan_req = NULL; 640 local->scanning = 0; 641 642 ieee80211_recalc_idle(local); 643 644 local->scan_req = NULL; 645 RCU_INIT_POINTER(local->scan_sdata, NULL); 646 } 647 648 return rc; 649 } 650 651 static unsigned long 652 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 653 { 654 /* 655 * TODO: channel switching also consumes quite some time, 656 * add that delay as well to get a better estimation 657 */ 658 if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) 659 return IEEE80211_PASSIVE_CHANNEL_TIME; 660 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 661 } 662 663 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 664 unsigned long *next_delay) 665 { 666 bool associated = false; 667 bool tx_empty = true; 668 bool bad_latency; 669 struct ieee80211_sub_if_data *sdata; 670 struct ieee80211_channel *next_chan; 671 enum mac80211_scan_state next_scan_state; 672 struct cfg80211_scan_request *scan_req; 673 674 /* 675 * check if at least one STA interface is associated, 676 * check if at least one STA interface has pending tx frames 677 * and grab the lowest used beacon interval 678 */ 679 mutex_lock(&local->iflist_mtx); 680 list_for_each_entry(sdata, &local->interfaces, list) { 681 if (!ieee80211_sdata_running(sdata)) 682 continue; 683 684 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 685 if (sdata->u.mgd.associated) { 686 associated = true; 687 688 if (!qdisc_all_tx_empty(sdata->dev)) { 689 tx_empty = false; 690 break; 691 } 692 } 693 } 694 } 695 mutex_unlock(&local->iflist_mtx); 696 697 scan_req = rcu_dereference_protected(local->scan_req, 698 lockdep_is_held(&local->mtx)); 699 700 next_chan = scan_req->channels[local->scan_channel_idx]; 701 702 /* 703 * we're currently scanning a different channel, let's 704 * see if we can scan another channel without interfering 705 * with the current traffic situation. 706 * 707 * Keep good latency, do not stay off-channel more than 125 ms. 708 */ 709 710 bad_latency = time_after(jiffies + 711 ieee80211_scan_get_channel_time(next_chan), 712 local->leave_oper_channel_time + HZ / 8); 713 714 if (associated && !tx_empty) { 715 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 716 next_scan_state = SCAN_ABORT; 717 else 718 next_scan_state = SCAN_SUSPEND; 719 } else if (associated && bad_latency) { 720 next_scan_state = SCAN_SUSPEND; 721 } else { 722 next_scan_state = SCAN_SET_CHANNEL; 723 } 724 725 local->next_scan_state = next_scan_state; 726 727 *next_delay = 0; 728 } 729 730 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 731 unsigned long *next_delay) 732 { 733 int skip; 734 struct ieee80211_channel *chan; 735 enum nl80211_bss_scan_width oper_scan_width; 736 struct cfg80211_scan_request *scan_req; 737 738 scan_req = rcu_dereference_protected(local->scan_req, 739 lockdep_is_held(&local->mtx)); 740 741 skip = 0; 742 chan = scan_req->channels[local->scan_channel_idx]; 743 744 local->scan_chandef.chan = chan; 745 local->scan_chandef.center_freq1 = chan->center_freq; 746 local->scan_chandef.center_freq2 = 0; 747 switch (scan_req->scan_width) { 748 case NL80211_BSS_CHAN_WIDTH_5: 749 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 750 break; 751 case NL80211_BSS_CHAN_WIDTH_10: 752 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 753 break; 754 case NL80211_BSS_CHAN_WIDTH_20: 755 /* If scanning on oper channel, use whatever channel-type 756 * is currently in use. 757 */ 758 oper_scan_width = cfg80211_chandef_to_scan_width( 759 &local->_oper_chandef); 760 if (chan == local->_oper_chandef.chan && 761 oper_scan_width == scan_req->scan_width) 762 local->scan_chandef = local->_oper_chandef; 763 else 764 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 765 break; 766 } 767 768 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 769 skip = 1; 770 771 /* advance state machine to next channel/band */ 772 local->scan_channel_idx++; 773 774 if (skip) { 775 /* if we skip this channel return to the decision state */ 776 local->next_scan_state = SCAN_DECISION; 777 return; 778 } 779 780 /* 781 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 782 * (which unfortunately doesn't say _why_ step a) is done, 783 * but it waits for the probe delay or until a frame is 784 * received - and the received frame would update the NAV). 785 * For now, we do not support waiting until a frame is 786 * received. 787 * 788 * In any case, it is not necessary for a passive scan. 789 */ 790 if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) || 791 !scan_req->n_ssids) { 792 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 793 local->next_scan_state = SCAN_DECISION; 794 return; 795 } 796 797 /* active scan, send probes */ 798 *next_delay = IEEE80211_PROBE_DELAY; 799 local->next_scan_state = SCAN_SEND_PROBE; 800 } 801 802 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 803 unsigned long *next_delay) 804 { 805 /* switch back to the operating channel */ 806 local->scan_chandef.chan = NULL; 807 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 808 809 /* disable PS */ 810 ieee80211_offchannel_return(local); 811 812 *next_delay = HZ / 5; 813 /* afterwards, resume scan & go to next channel */ 814 local->next_scan_state = SCAN_RESUME; 815 } 816 817 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 818 unsigned long *next_delay) 819 { 820 ieee80211_offchannel_stop_vifs(local); 821 822 if (local->ops->flush) { 823 ieee80211_flush_queues(local, NULL, false); 824 *next_delay = 0; 825 } else 826 *next_delay = HZ / 10; 827 828 /* remember when we left the operating channel */ 829 local->leave_oper_channel_time = jiffies; 830 831 /* advance to the next channel to be scanned */ 832 local->next_scan_state = SCAN_SET_CHANNEL; 833 } 834 835 void ieee80211_scan_work(struct work_struct *work) 836 { 837 struct ieee80211_local *local = 838 container_of(work, struct ieee80211_local, scan_work.work); 839 struct ieee80211_sub_if_data *sdata; 840 struct cfg80211_scan_request *scan_req; 841 unsigned long next_delay = 0; 842 bool aborted; 843 844 mutex_lock(&local->mtx); 845 846 if (!ieee80211_can_run_worker(local)) { 847 aborted = true; 848 goto out_complete; 849 } 850 851 sdata = rcu_dereference_protected(local->scan_sdata, 852 lockdep_is_held(&local->mtx)); 853 scan_req = rcu_dereference_protected(local->scan_req, 854 lockdep_is_held(&local->mtx)); 855 856 /* When scanning on-channel, the first-callback means completed. */ 857 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 858 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 859 goto out_complete; 860 } 861 862 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 863 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 864 goto out_complete; 865 } 866 867 if (!sdata || !scan_req) 868 goto out; 869 870 if (!local->scanning) { 871 int rc; 872 873 RCU_INIT_POINTER(local->scan_req, NULL); 874 RCU_INIT_POINTER(local->scan_sdata, NULL); 875 876 rc = __ieee80211_start_scan(sdata, scan_req); 877 if (rc) { 878 /* need to complete scan in cfg80211 */ 879 rcu_assign_pointer(local->scan_req, scan_req); 880 aborted = true; 881 goto out_complete; 882 } else 883 goto out; 884 } 885 886 /* 887 * as long as no delay is required advance immediately 888 * without scheduling a new work 889 */ 890 do { 891 if (!ieee80211_sdata_running(sdata)) { 892 aborted = true; 893 goto out_complete; 894 } 895 896 switch (local->next_scan_state) { 897 case SCAN_DECISION: 898 /* if no more bands/channels left, complete scan */ 899 if (local->scan_channel_idx >= scan_req->n_channels) { 900 aborted = false; 901 goto out_complete; 902 } 903 ieee80211_scan_state_decision(local, &next_delay); 904 break; 905 case SCAN_SET_CHANNEL: 906 ieee80211_scan_state_set_channel(local, &next_delay); 907 break; 908 case SCAN_SEND_PROBE: 909 ieee80211_scan_state_send_probe(local, &next_delay); 910 break; 911 case SCAN_SUSPEND: 912 ieee80211_scan_state_suspend(local, &next_delay); 913 break; 914 case SCAN_RESUME: 915 ieee80211_scan_state_resume(local, &next_delay); 916 break; 917 case SCAN_ABORT: 918 aborted = true; 919 goto out_complete; 920 } 921 } while (next_delay == 0); 922 923 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 924 goto out; 925 926 out_complete: 927 __ieee80211_scan_completed(&local->hw, aborted); 928 out: 929 mutex_unlock(&local->mtx); 930 } 931 932 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 933 struct cfg80211_scan_request *req) 934 { 935 int res; 936 937 mutex_lock(&sdata->local->mtx); 938 res = __ieee80211_start_scan(sdata, req); 939 mutex_unlock(&sdata->local->mtx); 940 941 return res; 942 } 943 944 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 945 const u8 *ssid, u8 ssid_len, 946 struct ieee80211_channel **channels, 947 unsigned int n_channels, 948 enum nl80211_bss_scan_width scan_width) 949 { 950 struct ieee80211_local *local = sdata->local; 951 int ret = -EBUSY, i, n_ch = 0; 952 enum ieee80211_band band; 953 954 mutex_lock(&local->mtx); 955 956 /* busy scanning */ 957 if (local->scan_req) 958 goto unlock; 959 960 /* fill internal scan request */ 961 if (!channels) { 962 int max_n; 963 964 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 965 if (!local->hw.wiphy->bands[band]) 966 continue; 967 968 max_n = local->hw.wiphy->bands[band]->n_channels; 969 for (i = 0; i < max_n; i++) { 970 struct ieee80211_channel *tmp_ch = 971 &local->hw.wiphy->bands[band]->channels[i]; 972 973 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR | 974 IEEE80211_CHAN_DISABLED)) 975 continue; 976 977 local->int_scan_req->channels[n_ch] = tmp_ch; 978 n_ch++; 979 } 980 } 981 982 if (WARN_ON_ONCE(n_ch == 0)) 983 goto unlock; 984 985 local->int_scan_req->n_channels = n_ch; 986 } else { 987 for (i = 0; i < n_channels; i++) { 988 if (channels[i]->flags & (IEEE80211_CHAN_NO_IR | 989 IEEE80211_CHAN_DISABLED)) 990 continue; 991 992 local->int_scan_req->channels[n_ch] = channels[i]; 993 n_ch++; 994 } 995 996 if (WARN_ON_ONCE(n_ch == 0)) 997 goto unlock; 998 999 local->int_scan_req->n_channels = n_ch; 1000 } 1001 1002 local->int_scan_req->ssids = &local->scan_ssid; 1003 local->int_scan_req->n_ssids = 1; 1004 local->int_scan_req->scan_width = scan_width; 1005 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 1006 local->int_scan_req->ssids[0].ssid_len = ssid_len; 1007 1008 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 1009 unlock: 1010 mutex_unlock(&local->mtx); 1011 return ret; 1012 } 1013 1014 /* 1015 * Only call this function when a scan can't be queued -- under RTNL. 1016 */ 1017 void ieee80211_scan_cancel(struct ieee80211_local *local) 1018 { 1019 /* 1020 * We are canceling software scan, or deferred scan that was not 1021 * yet really started (see __ieee80211_start_scan ). 1022 * 1023 * Regarding hardware scan: 1024 * - we can not call __ieee80211_scan_completed() as when 1025 * SCAN_HW_SCANNING bit is set this function change 1026 * local->hw_scan_req to operate on 5G band, what race with 1027 * driver which can use local->hw_scan_req 1028 * 1029 * - we can not cancel scan_work since driver can schedule it 1030 * by ieee80211_scan_completed(..., true) to finish scan 1031 * 1032 * Hence we only call the cancel_hw_scan() callback, but the low-level 1033 * driver is still responsible for calling ieee80211_scan_completed() 1034 * after the scan was completed/aborted. 1035 */ 1036 1037 mutex_lock(&local->mtx); 1038 if (!local->scan_req) 1039 goto out; 1040 1041 /* 1042 * We have a scan running and the driver already reported completion, 1043 * but the worker hasn't run yet or is stuck on the mutex - mark it as 1044 * cancelled. 1045 */ 1046 if (test_bit(SCAN_HW_SCANNING, &local->scanning) && 1047 test_bit(SCAN_COMPLETED, &local->scanning)) { 1048 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1049 goto out; 1050 } 1051 1052 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 1053 /* 1054 * Make sure that __ieee80211_scan_completed doesn't trigger a 1055 * scan on another band. 1056 */ 1057 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1058 if (local->ops->cancel_hw_scan) 1059 drv_cancel_hw_scan(local, 1060 rcu_dereference_protected(local->scan_sdata, 1061 lockdep_is_held(&local->mtx))); 1062 goto out; 1063 } 1064 1065 /* 1066 * If the work is currently running, it must be blocked on 1067 * the mutex, but we'll set scan_sdata = NULL and it'll 1068 * simply exit once it acquires the mutex. 1069 */ 1070 cancel_delayed_work(&local->scan_work); 1071 /* and clean up */ 1072 __ieee80211_scan_completed(&local->hw, true); 1073 out: 1074 mutex_unlock(&local->mtx); 1075 } 1076 1077 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1078 struct cfg80211_sched_scan_request *req) 1079 { 1080 struct ieee80211_local *local = sdata->local; 1081 struct ieee80211_scan_ies sched_scan_ies = {}; 1082 struct cfg80211_chan_def chandef; 1083 int ret, i, iebufsz, num_bands = 0; 1084 u32 rate_masks[IEEE80211_NUM_BANDS] = {}; 1085 u8 bands_used = 0; 1086 u8 *ie; 1087 size_t len; 1088 1089 iebufsz = local->scan_ies_len + req->ie_len; 1090 1091 lockdep_assert_held(&local->mtx); 1092 1093 if (!local->ops->sched_scan_start) 1094 return -ENOTSUPP; 1095 1096 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 1097 if (local->hw.wiphy->bands[i]) { 1098 bands_used |= BIT(i); 1099 rate_masks[i] = (u32) -1; 1100 num_bands++; 1101 } 1102 } 1103 1104 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL); 1105 if (!ie) { 1106 ret = -ENOMEM; 1107 goto out; 1108 } 1109 1110 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 1111 1112 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz, 1113 &sched_scan_ies, req->ie, 1114 req->ie_len, bands_used, 1115 rate_masks, &chandef); 1116 1117 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1118 if (ret == 0) { 1119 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1120 rcu_assign_pointer(local->sched_scan_req, req); 1121 } 1122 1123 kfree(ie); 1124 1125 out: 1126 if (ret) { 1127 /* Clean in case of failure after HW restart or upon resume. */ 1128 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1129 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1130 } 1131 1132 return ret; 1133 } 1134 1135 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1136 struct cfg80211_sched_scan_request *req) 1137 { 1138 struct ieee80211_local *local = sdata->local; 1139 int ret; 1140 1141 mutex_lock(&local->mtx); 1142 1143 if (rcu_access_pointer(local->sched_scan_sdata)) { 1144 mutex_unlock(&local->mtx); 1145 return -EBUSY; 1146 } 1147 1148 ret = __ieee80211_request_sched_scan_start(sdata, req); 1149 1150 mutex_unlock(&local->mtx); 1151 return ret; 1152 } 1153 1154 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local) 1155 { 1156 struct ieee80211_sub_if_data *sched_scan_sdata; 1157 int ret = -ENOENT; 1158 1159 mutex_lock(&local->mtx); 1160 1161 if (!local->ops->sched_scan_stop) { 1162 ret = -ENOTSUPP; 1163 goto out; 1164 } 1165 1166 /* We don't want to restart sched scan anymore. */ 1167 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1168 1169 sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata, 1170 lockdep_is_held(&local->mtx)); 1171 if (sched_scan_sdata) { 1172 ret = drv_sched_scan_stop(local, sched_scan_sdata); 1173 if (!ret) 1174 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1175 } 1176 out: 1177 mutex_unlock(&local->mtx); 1178 1179 return ret; 1180 } 1181 1182 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1183 { 1184 struct ieee80211_local *local = hw_to_local(hw); 1185 1186 trace_api_sched_scan_results(local); 1187 1188 cfg80211_sched_scan_results(hw->wiphy); 1189 } 1190 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1191 1192 void ieee80211_sched_scan_end(struct ieee80211_local *local) 1193 { 1194 mutex_lock(&local->mtx); 1195 1196 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1197 mutex_unlock(&local->mtx); 1198 return; 1199 } 1200 1201 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1202 1203 /* If sched scan was aborted by the driver. */ 1204 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1205 1206 mutex_unlock(&local->mtx); 1207 1208 cfg80211_sched_scan_stopped(local->hw.wiphy); 1209 } 1210 1211 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1212 { 1213 struct ieee80211_local *local = 1214 container_of(work, struct ieee80211_local, 1215 sched_scan_stopped_work); 1216 1217 ieee80211_sched_scan_end(local); 1218 } 1219 1220 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1221 { 1222 struct ieee80211_local *local = hw_to_local(hw); 1223 1224 trace_api_sched_scan_stopped(local); 1225 1226 /* 1227 * this shouldn't really happen, so for simplicity 1228 * simply ignore it, and let mac80211 reconfigure 1229 * the sched scan later on. 1230 */ 1231 if (local->in_reconfig) 1232 return; 1233 1234 schedule_work(&local->sched_scan_stopped_work); 1235 } 1236 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1237