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 <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 bool signal_valid; 73 74 if (ieee80211_hw_check(&local->hw, SIGNAL_DBM)) 75 signal = rx_status->signal * 100; 76 else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC)) 77 signal = (rx_status->signal * 100) / local->hw.max_signal; 78 79 scan_width = NL80211_BSS_CHAN_WIDTH_20; 80 if (rx_status->flag & RX_FLAG_5MHZ) 81 scan_width = NL80211_BSS_CHAN_WIDTH_5; 82 if (rx_status->flag & RX_FLAG_10MHZ) 83 scan_width = NL80211_BSS_CHAN_WIDTH_10; 84 85 cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel, 86 scan_width, mgmt, len, signal, 87 GFP_ATOMIC); 88 if (!cbss) 89 return NULL; 90 /* In case the signal is invalid update the status */ 91 signal_valid = abs(channel->center_freq - cbss->channel->center_freq) 92 <= local->hw.wiphy->max_adj_channel_rssi_comp; 93 if (!signal_valid) 94 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL; 95 96 bss = (void *)cbss->priv; 97 98 if (beacon) 99 bss->device_ts_beacon = rx_status->device_timestamp; 100 else 101 bss->device_ts_presp = rx_status->device_timestamp; 102 103 if (elems->parse_error) { 104 if (beacon) 105 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; 106 else 107 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; 108 } else { 109 if (beacon) 110 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; 111 else 112 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; 113 } 114 115 /* save the ERP value so that it is available at association time */ 116 if (elems->erp_info && (!elems->parse_error || 117 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { 118 bss->erp_value = elems->erp_info[0]; 119 bss->has_erp_value = true; 120 if (!elems->parse_error) 121 bss->valid_data |= IEEE80211_BSS_VALID_ERP; 122 } 123 124 /* replace old supported rates if we get new values */ 125 if (!elems->parse_error || 126 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { 127 srlen = 0; 128 if (elems->supp_rates) { 129 clen = IEEE80211_MAX_SUPP_RATES; 130 if (clen > elems->supp_rates_len) 131 clen = elems->supp_rates_len; 132 memcpy(bss->supp_rates, elems->supp_rates, clen); 133 srlen += clen; 134 } 135 if (elems->ext_supp_rates) { 136 clen = IEEE80211_MAX_SUPP_RATES - srlen; 137 if (clen > elems->ext_supp_rates_len) 138 clen = elems->ext_supp_rates_len; 139 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, 140 clen); 141 srlen += clen; 142 } 143 if (srlen) { 144 bss->supp_rates_len = srlen; 145 if (!elems->parse_error) 146 bss->valid_data |= IEEE80211_BSS_VALID_RATES; 147 } 148 } 149 150 if (!elems->parse_error || 151 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { 152 bss->wmm_used = elems->wmm_param || elems->wmm_info; 153 bss->uapsd_supported = is_uapsd_supported(elems); 154 if (!elems->parse_error) 155 bss->valid_data |= IEEE80211_BSS_VALID_WMM; 156 } 157 158 if (beacon) { 159 struct ieee80211_supported_band *sband = 160 local->hw.wiphy->bands[rx_status->band]; 161 if (!(rx_status->flag & RX_FLAG_HT) && 162 !(rx_status->flag & RX_FLAG_VHT)) 163 bss->beacon_rate = 164 &sband->bitrates[rx_status->rate_idx]; 165 } 166 167 return bss; 168 } 169 170 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) 171 { 172 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); 173 struct ieee80211_sub_if_data *sdata1, *sdata2; 174 struct ieee80211_mgmt *mgmt = (void *)skb->data; 175 struct ieee80211_bss *bss; 176 u8 *elements; 177 struct ieee80211_channel *channel; 178 size_t baselen; 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 struct cfg80211_scan_request *scan_req; 194 struct cfg80211_sched_scan_request *sched_scan_req; 195 196 scan_req = rcu_dereference(local->scan_req); 197 sched_scan_req = rcu_dereference(local->sched_scan_req); 198 199 /* ignore ProbeResp to foreign address unless scanning 200 * with randomised address 201 */ 202 if (!(sdata1 && 203 (ether_addr_equal(mgmt->da, sdata1->vif.addr) || 204 scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) && 205 !(sdata2 && 206 (ether_addr_equal(mgmt->da, sdata2->vif.addr) || 207 sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR))) 208 return; 209 210 elements = mgmt->u.probe_resp.variable; 211 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 212 } else { 213 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 214 elements = mgmt->u.beacon.variable; 215 } 216 217 if (baselen > skb->len) 218 return; 219 220 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems); 221 222 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); 223 224 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 225 return; 226 227 bss = ieee80211_bss_info_update(local, rx_status, 228 mgmt, skb->len, &elems, 229 channel); 230 if (bss) 231 ieee80211_rx_bss_put(local, bss); 232 } 233 234 static void 235 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef, 236 enum nl80211_bss_scan_width scan_width) 237 { 238 memset(chandef, 0, sizeof(*chandef)); 239 switch (scan_width) { 240 case NL80211_BSS_CHAN_WIDTH_5: 241 chandef->width = NL80211_CHAN_WIDTH_5; 242 break; 243 case NL80211_BSS_CHAN_WIDTH_10: 244 chandef->width = NL80211_CHAN_WIDTH_10; 245 break; 246 default: 247 chandef->width = NL80211_CHAN_WIDTH_20_NOHT; 248 break; 249 } 250 } 251 252 /* return false if no more work */ 253 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 254 { 255 struct cfg80211_scan_request *req; 256 struct cfg80211_chan_def chandef; 257 u8 bands_used = 0; 258 int i, ielen, n_chans; 259 260 req = rcu_dereference_protected(local->scan_req, 261 lockdep_is_held(&local->mtx)); 262 263 if (test_bit(SCAN_HW_CANCELLED, &local->scanning)) 264 return false; 265 266 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { 267 for (i = 0; i < req->n_channels; i++) { 268 local->hw_scan_req->req.channels[i] = req->channels[i]; 269 bands_used |= BIT(req->channels[i]->band); 270 } 271 272 n_chans = req->n_channels; 273 } else { 274 do { 275 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 276 return false; 277 278 n_chans = 0; 279 280 for (i = 0; i < req->n_channels; i++) { 281 if (req->channels[i]->band != 282 local->hw_scan_band) 283 continue; 284 local->hw_scan_req->req.channels[n_chans] = 285 req->channels[i]; 286 n_chans++; 287 bands_used |= BIT(req->channels[i]->band); 288 } 289 290 local->hw_scan_band++; 291 } while (!n_chans); 292 } 293 294 local->hw_scan_req->req.n_channels = n_chans; 295 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 296 297 ielen = ieee80211_build_preq_ies(local, 298 (u8 *)local->hw_scan_req->req.ie, 299 local->hw_scan_ies_bufsize, 300 &local->hw_scan_req->ies, 301 req->ie, req->ie_len, 302 bands_used, req->rates, &chandef); 303 local->hw_scan_req->req.ie_len = ielen; 304 local->hw_scan_req->req.no_cck = req->no_cck; 305 ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr); 306 ether_addr_copy(local->hw_scan_req->req.mac_addr_mask, 307 req->mac_addr_mask); 308 309 return true; 310 } 311 312 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 313 { 314 struct ieee80211_local *local = hw_to_local(hw); 315 bool hw_scan = local->ops->hw_scan; 316 bool was_scanning = local->scanning; 317 struct cfg80211_scan_request *scan_req; 318 struct ieee80211_sub_if_data *scan_sdata; 319 320 lockdep_assert_held(&local->mtx); 321 322 /* 323 * It's ok to abort a not-yet-running scan (that 324 * we have one at all will be verified by checking 325 * local->scan_req next), but not to complete it 326 * successfully. 327 */ 328 if (WARN_ON(!local->scanning && !aborted)) 329 aborted = true; 330 331 if (WARN_ON(!local->scan_req)) 332 return; 333 334 if (hw_scan && !aborted && 335 !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) && 336 ieee80211_prep_hw_scan(local)) { 337 int rc; 338 339 rc = drv_hw_scan(local, 340 rcu_dereference_protected(local->scan_sdata, 341 lockdep_is_held(&local->mtx)), 342 local->hw_scan_req); 343 344 if (rc == 0) 345 return; 346 } 347 348 kfree(local->hw_scan_req); 349 local->hw_scan_req = NULL; 350 351 scan_req = rcu_dereference_protected(local->scan_req, 352 lockdep_is_held(&local->mtx)); 353 354 if (scan_req != local->int_scan_req) 355 cfg80211_scan_done(scan_req, aborted); 356 RCU_INIT_POINTER(local->scan_req, NULL); 357 358 scan_sdata = rcu_dereference_protected(local->scan_sdata, 359 lockdep_is_held(&local->mtx)); 360 RCU_INIT_POINTER(local->scan_sdata, NULL); 361 362 local->scanning = 0; 363 local->scan_chandef.chan = NULL; 364 365 /* Set power back to normal operating levels. */ 366 ieee80211_hw_config(local, 0); 367 368 if (!hw_scan) { 369 ieee80211_configure_filter(local); 370 drv_sw_scan_complete(local, scan_sdata); 371 ieee80211_offchannel_return(local); 372 } 373 374 ieee80211_recalc_idle(local); 375 376 ieee80211_mlme_notify_scan_completed(local); 377 ieee80211_ibss_notify_scan_completed(local); 378 ieee80211_mesh_notify_scan_completed(local); 379 if (was_scanning) 380 ieee80211_start_next_roc(local); 381 } 382 383 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 384 { 385 struct ieee80211_local *local = hw_to_local(hw); 386 387 trace_api_scan_completed(local, aborted); 388 389 set_bit(SCAN_COMPLETED, &local->scanning); 390 if (aborted) 391 set_bit(SCAN_ABORTED, &local->scanning); 392 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 393 } 394 EXPORT_SYMBOL(ieee80211_scan_completed); 395 396 static int ieee80211_start_sw_scan(struct ieee80211_local *local, 397 struct ieee80211_sub_if_data *sdata) 398 { 399 /* Software scan is not supported in multi-channel cases */ 400 if (local->use_chanctx) 401 return -EOPNOTSUPP; 402 403 /* 404 * Hardware/driver doesn't support hw_scan, so use software 405 * scanning instead. First send a nullfunc frame with power save 406 * bit on so that AP will buffer the frames for us while we are not 407 * listening, then send probe requests to each channel and wait for 408 * the responses. After all channels are scanned, tune back to the 409 * original channel and send a nullfunc frame with power save bit 410 * off to trigger the AP to send us all the buffered frames. 411 * 412 * Note that while local->sw_scanning is true everything else but 413 * nullfunc frames and probe requests will be dropped in 414 * ieee80211_tx_h_check_assoc(). 415 */ 416 drv_sw_scan_start(local, sdata, local->scan_addr); 417 418 local->leave_oper_channel_time = jiffies; 419 local->next_scan_state = SCAN_DECISION; 420 local->scan_channel_idx = 0; 421 422 ieee80211_offchannel_stop_vifs(local); 423 424 /* ensure nullfunc is transmitted before leaving operating channel */ 425 ieee80211_flush_queues(local, NULL, false); 426 427 ieee80211_configure_filter(local); 428 429 /* We need to set power level at maximum rate for scanning. */ 430 ieee80211_hw_config(local, 0); 431 432 ieee80211_queue_delayed_work(&local->hw, 433 &local->scan_work, 0); 434 435 return 0; 436 } 437 438 static bool ieee80211_can_scan(struct ieee80211_local *local, 439 struct ieee80211_sub_if_data *sdata) 440 { 441 if (ieee80211_is_radar_required(local)) 442 return false; 443 444 if (!list_empty(&local->roc_list)) 445 return false; 446 447 if (sdata->vif.type == NL80211_IFTYPE_STATION && 448 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL) 449 return false; 450 451 return true; 452 } 453 454 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 455 { 456 lockdep_assert_held(&local->mtx); 457 458 if (!local->scan_req || local->scanning) 459 return; 460 461 if (!ieee80211_can_scan(local, 462 rcu_dereference_protected( 463 local->scan_sdata, 464 lockdep_is_held(&local->mtx)))) 465 return; 466 467 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 468 round_jiffies_relative(0)); 469 } 470 471 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 472 unsigned long *next_delay) 473 { 474 int i; 475 struct ieee80211_sub_if_data *sdata; 476 struct cfg80211_scan_request *scan_req; 477 enum ieee80211_band band = local->hw.conf.chandef.chan->band; 478 u32 tx_flags; 479 480 scan_req = rcu_dereference_protected(local->scan_req, 481 lockdep_is_held(&local->mtx)); 482 483 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 484 if (scan_req->no_cck) 485 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 486 487 sdata = rcu_dereference_protected(local->scan_sdata, 488 lockdep_is_held(&local->mtx)); 489 490 for (i = 0; i < scan_req->n_ssids; i++) 491 ieee80211_send_probe_req( 492 sdata, local->scan_addr, NULL, 493 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len, 494 scan_req->ie, scan_req->ie_len, 495 scan_req->rates[band], false, 496 tx_flags, local->hw.conf.chandef.chan, true); 497 498 /* 499 * After sending probe requests, wait for probe responses 500 * on the channel. 501 */ 502 *next_delay = IEEE80211_CHANNEL_TIME; 503 local->next_scan_state = SCAN_DECISION; 504 } 505 506 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 507 struct cfg80211_scan_request *req) 508 { 509 struct ieee80211_local *local = sdata->local; 510 int rc; 511 512 lockdep_assert_held(&local->mtx); 513 514 if (local->scan_req || ieee80211_is_radar_required(local)) 515 return -EBUSY; 516 517 if (!ieee80211_can_scan(local, sdata)) { 518 /* wait for the work to finish/time out */ 519 rcu_assign_pointer(local->scan_req, req); 520 rcu_assign_pointer(local->scan_sdata, sdata); 521 return 0; 522 } 523 524 if (local->ops->hw_scan) { 525 u8 *ies; 526 527 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len; 528 529 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { 530 int i, n_bands = 0; 531 u8 bands_counted = 0; 532 533 for (i = 0; i < req->n_channels; i++) { 534 if (bands_counted & BIT(req->channels[i]->band)) 535 continue; 536 bands_counted |= BIT(req->channels[i]->band); 537 n_bands++; 538 } 539 540 local->hw_scan_ies_bufsize *= n_bands; 541 } 542 543 local->hw_scan_req = kmalloc( 544 sizeof(*local->hw_scan_req) + 545 req->n_channels * sizeof(req->channels[0]) + 546 local->hw_scan_ies_bufsize, GFP_KERNEL); 547 if (!local->hw_scan_req) 548 return -ENOMEM; 549 550 local->hw_scan_req->req.ssids = req->ssids; 551 local->hw_scan_req->req.n_ssids = req->n_ssids; 552 ies = (u8 *)local->hw_scan_req + 553 sizeof(*local->hw_scan_req) + 554 req->n_channels * sizeof(req->channels[0]); 555 local->hw_scan_req->req.ie = ies; 556 local->hw_scan_req->req.flags = req->flags; 557 558 local->hw_scan_band = 0; 559 560 /* 561 * After allocating local->hw_scan_req, we must 562 * go through until ieee80211_prep_hw_scan(), so 563 * anything that might be changed here and leave 564 * this function early must not go after this 565 * allocation. 566 */ 567 } 568 569 rcu_assign_pointer(local->scan_req, req); 570 rcu_assign_pointer(local->scan_sdata, sdata); 571 572 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR) 573 get_random_mask_addr(local->scan_addr, 574 req->mac_addr, 575 req->mac_addr_mask); 576 else 577 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN); 578 579 if (local->ops->hw_scan) { 580 __set_bit(SCAN_HW_SCANNING, &local->scanning); 581 } else if ((req->n_channels == 1) && 582 (req->channels[0] == local->_oper_chandef.chan)) { 583 /* 584 * If we are scanning only on the operating channel 585 * then we do not need to stop normal activities 586 */ 587 unsigned long next_delay; 588 589 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 590 591 ieee80211_recalc_idle(local); 592 593 /* Notify driver scan is starting, keep order of operations 594 * same as normal software scan, in case that matters. */ 595 drv_sw_scan_start(local, sdata, local->scan_addr); 596 597 ieee80211_configure_filter(local); /* accept probe-responses */ 598 599 /* We need to ensure power level is at max for scanning. */ 600 ieee80211_hw_config(local, 0); 601 602 if ((req->channels[0]->flags & 603 IEEE80211_CHAN_NO_IR) || 604 !req->n_ssids) { 605 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 606 } else { 607 ieee80211_scan_state_send_probe(local, &next_delay); 608 next_delay = IEEE80211_CHANNEL_TIME; 609 } 610 611 /* Now, just wait a bit and we are all done! */ 612 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 613 next_delay); 614 return 0; 615 } else { 616 /* Do normal software scan */ 617 __set_bit(SCAN_SW_SCANNING, &local->scanning); 618 } 619 620 ieee80211_recalc_idle(local); 621 622 if (local->ops->hw_scan) { 623 WARN_ON(!ieee80211_prep_hw_scan(local)); 624 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 625 } else { 626 rc = ieee80211_start_sw_scan(local, sdata); 627 } 628 629 if (rc) { 630 kfree(local->hw_scan_req); 631 local->hw_scan_req = NULL; 632 local->scanning = 0; 633 634 ieee80211_recalc_idle(local); 635 636 local->scan_req = NULL; 637 RCU_INIT_POINTER(local->scan_sdata, NULL); 638 } 639 640 return rc; 641 } 642 643 static unsigned long 644 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 645 { 646 /* 647 * TODO: channel switching also consumes quite some time, 648 * add that delay as well to get a better estimation 649 */ 650 if (chan->flags & IEEE80211_CHAN_NO_IR) 651 return IEEE80211_PASSIVE_CHANNEL_TIME; 652 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 653 } 654 655 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 656 unsigned long *next_delay) 657 { 658 bool associated = false; 659 bool tx_empty = true; 660 bool bad_latency; 661 struct ieee80211_sub_if_data *sdata; 662 struct ieee80211_channel *next_chan; 663 enum mac80211_scan_state next_scan_state; 664 struct cfg80211_scan_request *scan_req; 665 666 /* 667 * check if at least one STA interface is associated, 668 * check if at least one STA interface has pending tx frames 669 * and grab the lowest used beacon interval 670 */ 671 mutex_lock(&local->iflist_mtx); 672 list_for_each_entry(sdata, &local->interfaces, list) { 673 if (!ieee80211_sdata_running(sdata)) 674 continue; 675 676 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 677 if (sdata->u.mgd.associated) { 678 associated = true; 679 680 if (!qdisc_all_tx_empty(sdata->dev)) { 681 tx_empty = false; 682 break; 683 } 684 } 685 } 686 } 687 mutex_unlock(&local->iflist_mtx); 688 689 scan_req = rcu_dereference_protected(local->scan_req, 690 lockdep_is_held(&local->mtx)); 691 692 next_chan = scan_req->channels[local->scan_channel_idx]; 693 694 /* 695 * we're currently scanning a different channel, let's 696 * see if we can scan another channel without interfering 697 * with the current traffic situation. 698 * 699 * Keep good latency, do not stay off-channel more than 125 ms. 700 */ 701 702 bad_latency = time_after(jiffies + 703 ieee80211_scan_get_channel_time(next_chan), 704 local->leave_oper_channel_time + HZ / 8); 705 706 if (associated && !tx_empty) { 707 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 708 next_scan_state = SCAN_ABORT; 709 else 710 next_scan_state = SCAN_SUSPEND; 711 } else if (associated && bad_latency) { 712 next_scan_state = SCAN_SUSPEND; 713 } else { 714 next_scan_state = SCAN_SET_CHANNEL; 715 } 716 717 local->next_scan_state = next_scan_state; 718 719 *next_delay = 0; 720 } 721 722 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 723 unsigned long *next_delay) 724 { 725 int skip; 726 struct ieee80211_channel *chan; 727 enum nl80211_bss_scan_width oper_scan_width; 728 struct cfg80211_scan_request *scan_req; 729 730 scan_req = rcu_dereference_protected(local->scan_req, 731 lockdep_is_held(&local->mtx)); 732 733 skip = 0; 734 chan = scan_req->channels[local->scan_channel_idx]; 735 736 local->scan_chandef.chan = chan; 737 local->scan_chandef.center_freq1 = chan->center_freq; 738 local->scan_chandef.center_freq2 = 0; 739 switch (scan_req->scan_width) { 740 case NL80211_BSS_CHAN_WIDTH_5: 741 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 742 break; 743 case NL80211_BSS_CHAN_WIDTH_10: 744 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 745 break; 746 case NL80211_BSS_CHAN_WIDTH_20: 747 /* If scanning on oper channel, use whatever channel-type 748 * is currently in use. 749 */ 750 oper_scan_width = cfg80211_chandef_to_scan_width( 751 &local->_oper_chandef); 752 if (chan == local->_oper_chandef.chan && 753 oper_scan_width == scan_req->scan_width) 754 local->scan_chandef = local->_oper_chandef; 755 else 756 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 757 break; 758 } 759 760 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 761 skip = 1; 762 763 /* advance state machine to next channel/band */ 764 local->scan_channel_idx++; 765 766 if (skip) { 767 /* if we skip this channel return to the decision state */ 768 local->next_scan_state = SCAN_DECISION; 769 return; 770 } 771 772 /* 773 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 774 * (which unfortunately doesn't say _why_ step a) is done, 775 * but it waits for the probe delay or until a frame is 776 * received - and the received frame would update the NAV). 777 * For now, we do not support waiting until a frame is 778 * received. 779 * 780 * In any case, it is not necessary for a passive scan. 781 */ 782 if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) { 783 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 784 local->next_scan_state = SCAN_DECISION; 785 return; 786 } 787 788 /* active scan, send probes */ 789 *next_delay = IEEE80211_PROBE_DELAY; 790 local->next_scan_state = SCAN_SEND_PROBE; 791 } 792 793 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 794 unsigned long *next_delay) 795 { 796 /* switch back to the operating channel */ 797 local->scan_chandef.chan = NULL; 798 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 799 800 /* disable PS */ 801 ieee80211_offchannel_return(local); 802 803 *next_delay = HZ / 5; 804 /* afterwards, resume scan & go to next channel */ 805 local->next_scan_state = SCAN_RESUME; 806 } 807 808 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 809 unsigned long *next_delay) 810 { 811 ieee80211_offchannel_stop_vifs(local); 812 813 if (local->ops->flush) { 814 ieee80211_flush_queues(local, NULL, false); 815 *next_delay = 0; 816 } else 817 *next_delay = HZ / 10; 818 819 /* remember when we left the operating channel */ 820 local->leave_oper_channel_time = jiffies; 821 822 /* advance to the next channel to be scanned */ 823 local->next_scan_state = SCAN_SET_CHANNEL; 824 } 825 826 void ieee80211_scan_work(struct work_struct *work) 827 { 828 struct ieee80211_local *local = 829 container_of(work, struct ieee80211_local, scan_work.work); 830 struct ieee80211_sub_if_data *sdata; 831 struct cfg80211_scan_request *scan_req; 832 unsigned long next_delay = 0; 833 bool aborted; 834 835 mutex_lock(&local->mtx); 836 837 if (!ieee80211_can_run_worker(local)) { 838 aborted = true; 839 goto out_complete; 840 } 841 842 sdata = rcu_dereference_protected(local->scan_sdata, 843 lockdep_is_held(&local->mtx)); 844 scan_req = rcu_dereference_protected(local->scan_req, 845 lockdep_is_held(&local->mtx)); 846 847 /* When scanning on-channel, the first-callback means completed. */ 848 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 849 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 850 goto out_complete; 851 } 852 853 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 854 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 855 goto out_complete; 856 } 857 858 if (!sdata || !scan_req) 859 goto out; 860 861 if (!local->scanning) { 862 int rc; 863 864 RCU_INIT_POINTER(local->scan_req, NULL); 865 RCU_INIT_POINTER(local->scan_sdata, NULL); 866 867 rc = __ieee80211_start_scan(sdata, scan_req); 868 if (rc) { 869 /* need to complete scan in cfg80211 */ 870 rcu_assign_pointer(local->scan_req, scan_req); 871 aborted = true; 872 goto out_complete; 873 } else 874 goto out; 875 } 876 877 /* 878 * as long as no delay is required advance immediately 879 * without scheduling a new work 880 */ 881 do { 882 if (!ieee80211_sdata_running(sdata)) { 883 aborted = true; 884 goto out_complete; 885 } 886 887 switch (local->next_scan_state) { 888 case SCAN_DECISION: 889 /* if no more bands/channels left, complete scan */ 890 if (local->scan_channel_idx >= scan_req->n_channels) { 891 aborted = false; 892 goto out_complete; 893 } 894 ieee80211_scan_state_decision(local, &next_delay); 895 break; 896 case SCAN_SET_CHANNEL: 897 ieee80211_scan_state_set_channel(local, &next_delay); 898 break; 899 case SCAN_SEND_PROBE: 900 ieee80211_scan_state_send_probe(local, &next_delay); 901 break; 902 case SCAN_SUSPEND: 903 ieee80211_scan_state_suspend(local, &next_delay); 904 break; 905 case SCAN_RESUME: 906 ieee80211_scan_state_resume(local, &next_delay); 907 break; 908 case SCAN_ABORT: 909 aborted = true; 910 goto out_complete; 911 } 912 } while (next_delay == 0); 913 914 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 915 goto out; 916 917 out_complete: 918 __ieee80211_scan_completed(&local->hw, aborted); 919 out: 920 mutex_unlock(&local->mtx); 921 } 922 923 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 924 struct cfg80211_scan_request *req) 925 { 926 int res; 927 928 mutex_lock(&sdata->local->mtx); 929 res = __ieee80211_start_scan(sdata, req); 930 mutex_unlock(&sdata->local->mtx); 931 932 return res; 933 } 934 935 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 936 const u8 *ssid, u8 ssid_len, 937 struct ieee80211_channel **channels, 938 unsigned int n_channels, 939 enum nl80211_bss_scan_width scan_width) 940 { 941 struct ieee80211_local *local = sdata->local; 942 int ret = -EBUSY, i, n_ch = 0; 943 enum ieee80211_band band; 944 945 mutex_lock(&local->mtx); 946 947 /* busy scanning */ 948 if (local->scan_req) 949 goto unlock; 950 951 /* fill internal scan request */ 952 if (!channels) { 953 int max_n; 954 955 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 956 if (!local->hw.wiphy->bands[band]) 957 continue; 958 959 max_n = local->hw.wiphy->bands[band]->n_channels; 960 for (i = 0; i < max_n; i++) { 961 struct ieee80211_channel *tmp_ch = 962 &local->hw.wiphy->bands[band]->channels[i]; 963 964 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR | 965 IEEE80211_CHAN_DISABLED)) 966 continue; 967 968 local->int_scan_req->channels[n_ch] = tmp_ch; 969 n_ch++; 970 } 971 } 972 973 if (WARN_ON_ONCE(n_ch == 0)) 974 goto unlock; 975 976 local->int_scan_req->n_channels = n_ch; 977 } else { 978 for (i = 0; i < n_channels; i++) { 979 if (channels[i]->flags & (IEEE80211_CHAN_NO_IR | 980 IEEE80211_CHAN_DISABLED)) 981 continue; 982 983 local->int_scan_req->channels[n_ch] = channels[i]; 984 n_ch++; 985 } 986 987 if (WARN_ON_ONCE(n_ch == 0)) 988 goto unlock; 989 990 local->int_scan_req->n_channels = n_ch; 991 } 992 993 local->int_scan_req->ssids = &local->scan_ssid; 994 local->int_scan_req->n_ssids = 1; 995 local->int_scan_req->scan_width = scan_width; 996 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 997 local->int_scan_req->ssids[0].ssid_len = ssid_len; 998 999 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 1000 unlock: 1001 mutex_unlock(&local->mtx); 1002 return ret; 1003 } 1004 1005 /* 1006 * Only call this function when a scan can't be queued -- under RTNL. 1007 */ 1008 void ieee80211_scan_cancel(struct ieee80211_local *local) 1009 { 1010 /* 1011 * We are canceling software scan, or deferred scan that was not 1012 * yet really started (see __ieee80211_start_scan ). 1013 * 1014 * Regarding hardware scan: 1015 * - we can not call __ieee80211_scan_completed() as when 1016 * SCAN_HW_SCANNING bit is set this function change 1017 * local->hw_scan_req to operate on 5G band, what race with 1018 * driver which can use local->hw_scan_req 1019 * 1020 * - we can not cancel scan_work since driver can schedule it 1021 * by ieee80211_scan_completed(..., true) to finish scan 1022 * 1023 * Hence we only call the cancel_hw_scan() callback, but the low-level 1024 * driver is still responsible for calling ieee80211_scan_completed() 1025 * after the scan was completed/aborted. 1026 */ 1027 1028 mutex_lock(&local->mtx); 1029 if (!local->scan_req) 1030 goto out; 1031 1032 /* 1033 * We have a scan running and the driver already reported completion, 1034 * but the worker hasn't run yet or is stuck on the mutex - mark it as 1035 * cancelled. 1036 */ 1037 if (test_bit(SCAN_HW_SCANNING, &local->scanning) && 1038 test_bit(SCAN_COMPLETED, &local->scanning)) { 1039 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1040 goto out; 1041 } 1042 1043 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 1044 /* 1045 * Make sure that __ieee80211_scan_completed doesn't trigger a 1046 * scan on another band. 1047 */ 1048 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1049 if (local->ops->cancel_hw_scan) 1050 drv_cancel_hw_scan(local, 1051 rcu_dereference_protected(local->scan_sdata, 1052 lockdep_is_held(&local->mtx))); 1053 goto out; 1054 } 1055 1056 /* 1057 * If the work is currently running, it must be blocked on 1058 * the mutex, but we'll set scan_sdata = NULL and it'll 1059 * simply exit once it acquires the mutex. 1060 */ 1061 cancel_delayed_work(&local->scan_work); 1062 /* and clean up */ 1063 __ieee80211_scan_completed(&local->hw, true); 1064 out: 1065 mutex_unlock(&local->mtx); 1066 } 1067 1068 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1069 struct cfg80211_sched_scan_request *req) 1070 { 1071 struct ieee80211_local *local = sdata->local; 1072 struct ieee80211_scan_ies sched_scan_ies = {}; 1073 struct cfg80211_chan_def chandef; 1074 int ret, i, iebufsz, num_bands = 0; 1075 u32 rate_masks[IEEE80211_NUM_BANDS] = {}; 1076 u8 bands_used = 0; 1077 u8 *ie; 1078 size_t len; 1079 1080 iebufsz = local->scan_ies_len + req->ie_len; 1081 1082 lockdep_assert_held(&local->mtx); 1083 1084 if (!local->ops->sched_scan_start) 1085 return -ENOTSUPP; 1086 1087 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 1088 if (local->hw.wiphy->bands[i]) { 1089 bands_used |= BIT(i); 1090 rate_masks[i] = (u32) -1; 1091 num_bands++; 1092 } 1093 } 1094 1095 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL); 1096 if (!ie) { 1097 ret = -ENOMEM; 1098 goto out; 1099 } 1100 1101 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 1102 1103 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz, 1104 &sched_scan_ies, req->ie, 1105 req->ie_len, bands_used, 1106 rate_masks, &chandef); 1107 1108 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1109 if (ret == 0) { 1110 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1111 rcu_assign_pointer(local->sched_scan_req, req); 1112 } 1113 1114 kfree(ie); 1115 1116 out: 1117 if (ret) { 1118 /* Clean in case of failure after HW restart or upon resume. */ 1119 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1120 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1121 } 1122 1123 return ret; 1124 } 1125 1126 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1127 struct cfg80211_sched_scan_request *req) 1128 { 1129 struct ieee80211_local *local = sdata->local; 1130 int ret; 1131 1132 mutex_lock(&local->mtx); 1133 1134 if (rcu_access_pointer(local->sched_scan_sdata)) { 1135 mutex_unlock(&local->mtx); 1136 return -EBUSY; 1137 } 1138 1139 ret = __ieee80211_request_sched_scan_start(sdata, req); 1140 1141 mutex_unlock(&local->mtx); 1142 return ret; 1143 } 1144 1145 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 1146 { 1147 struct ieee80211_local *local = sdata->local; 1148 int ret = 0; 1149 1150 mutex_lock(&local->mtx); 1151 1152 if (!local->ops->sched_scan_stop) { 1153 ret = -ENOTSUPP; 1154 goto out; 1155 } 1156 1157 /* We don't want to restart sched scan anymore. */ 1158 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1159 1160 if (rcu_access_pointer(local->sched_scan_sdata)) { 1161 ret = drv_sched_scan_stop(local, sdata); 1162 if (!ret) 1163 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1164 } 1165 out: 1166 mutex_unlock(&local->mtx); 1167 1168 return ret; 1169 } 1170 1171 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1172 { 1173 struct ieee80211_local *local = hw_to_local(hw); 1174 1175 trace_api_sched_scan_results(local); 1176 1177 cfg80211_sched_scan_results(hw->wiphy); 1178 } 1179 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1180 1181 void ieee80211_sched_scan_end(struct ieee80211_local *local) 1182 { 1183 mutex_lock(&local->mtx); 1184 1185 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1186 mutex_unlock(&local->mtx); 1187 return; 1188 } 1189 1190 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1191 1192 /* If sched scan was aborted by the driver. */ 1193 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1194 1195 mutex_unlock(&local->mtx); 1196 1197 cfg80211_sched_scan_stopped(local->hw.wiphy); 1198 } 1199 1200 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1201 { 1202 struct ieee80211_local *local = 1203 container_of(work, struct ieee80211_local, 1204 sched_scan_stopped_work); 1205 1206 ieee80211_sched_scan_end(local); 1207 } 1208 1209 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1210 { 1211 struct ieee80211_local *local = hw_to_local(hw); 1212 1213 trace_api_sched_scan_stopped(local); 1214 1215 schedule_work(&local->sched_scan_stopped_work); 1216 } 1217 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1218