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; 317 318 lockdep_assert_held(&local->mtx); 319 320 /* 321 * It's ok to abort a not-yet-running scan (that 322 * we have one at all will be verified by checking 323 * local->scan_req next), but not to complete it 324 * successfully. 325 */ 326 if (WARN_ON(!local->scanning && !aborted)) 327 aborted = true; 328 329 if (WARN_ON(!local->scan_req)) 330 return; 331 332 if (hw_scan && !aborted && 333 !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) && 334 ieee80211_prep_hw_scan(local)) { 335 int rc; 336 337 rc = drv_hw_scan(local, 338 rcu_dereference_protected(local->scan_sdata, 339 lockdep_is_held(&local->mtx)), 340 local->hw_scan_req); 341 342 if (rc == 0) 343 return; 344 } 345 346 kfree(local->hw_scan_req); 347 local->hw_scan_req = NULL; 348 349 scan_req = rcu_dereference_protected(local->scan_req, 350 lockdep_is_held(&local->mtx)); 351 352 if (scan_req != local->int_scan_req) 353 cfg80211_scan_done(scan_req, aborted); 354 RCU_INIT_POINTER(local->scan_req, NULL); 355 356 scan_sdata = rcu_dereference_protected(local->scan_sdata, 357 lockdep_is_held(&local->mtx)); 358 RCU_INIT_POINTER(local->scan_sdata, NULL); 359 360 local->scanning = 0; 361 local->scan_chandef.chan = NULL; 362 363 /* Set power back to normal operating levels. */ 364 ieee80211_hw_config(local, 0); 365 366 if (!hw_scan) { 367 ieee80211_configure_filter(local); 368 drv_sw_scan_complete(local, scan_sdata); 369 ieee80211_offchannel_return(local); 370 } 371 372 ieee80211_recalc_idle(local); 373 374 ieee80211_mlme_notify_scan_completed(local); 375 ieee80211_ibss_notify_scan_completed(local); 376 ieee80211_mesh_notify_scan_completed(local); 377 if (was_scanning) 378 ieee80211_start_next_roc(local); 379 } 380 381 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 382 { 383 struct ieee80211_local *local = hw_to_local(hw); 384 385 trace_api_scan_completed(local, aborted); 386 387 set_bit(SCAN_COMPLETED, &local->scanning); 388 if (aborted) 389 set_bit(SCAN_ABORTED, &local->scanning); 390 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 391 } 392 EXPORT_SYMBOL(ieee80211_scan_completed); 393 394 static int ieee80211_start_sw_scan(struct ieee80211_local *local, 395 struct ieee80211_sub_if_data *sdata) 396 { 397 /* Software scan is not supported in multi-channel cases */ 398 if (local->use_chanctx) 399 return -EOPNOTSUPP; 400 401 /* 402 * Hardware/driver doesn't support hw_scan, so use software 403 * scanning instead. First send a nullfunc frame with power save 404 * bit on so that AP will buffer the frames for us while we are not 405 * listening, then send probe requests to each channel and wait for 406 * the responses. After all channels are scanned, tune back to the 407 * original channel and send a nullfunc frame with power save bit 408 * off to trigger the AP to send us all the buffered frames. 409 * 410 * Note that while local->sw_scanning is true everything else but 411 * nullfunc frames and probe requests will be dropped in 412 * ieee80211_tx_h_check_assoc(). 413 */ 414 drv_sw_scan_start(local, sdata, local->scan_addr); 415 416 local->leave_oper_channel_time = jiffies; 417 local->next_scan_state = SCAN_DECISION; 418 local->scan_channel_idx = 0; 419 420 ieee80211_offchannel_stop_vifs(local); 421 422 /* ensure nullfunc is transmitted before leaving operating channel */ 423 ieee80211_flush_queues(local, NULL, false); 424 425 ieee80211_configure_filter(local); 426 427 /* We need to set power level at maximum rate for scanning. */ 428 ieee80211_hw_config(local, 0); 429 430 ieee80211_queue_delayed_work(&local->hw, 431 &local->scan_work, 0); 432 433 return 0; 434 } 435 436 static bool ieee80211_can_scan(struct ieee80211_local *local, 437 struct ieee80211_sub_if_data *sdata) 438 { 439 if (ieee80211_is_radar_required(local)) 440 return false; 441 442 if (!list_empty(&local->roc_list)) 443 return false; 444 445 if (sdata->vif.type == NL80211_IFTYPE_STATION && 446 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL) 447 return false; 448 449 return true; 450 } 451 452 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 453 { 454 lockdep_assert_held(&local->mtx); 455 456 if (!local->scan_req || local->scanning) 457 return; 458 459 if (!ieee80211_can_scan(local, 460 rcu_dereference_protected( 461 local->scan_sdata, 462 lockdep_is_held(&local->mtx)))) 463 return; 464 465 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 466 round_jiffies_relative(0)); 467 } 468 469 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 470 unsigned long *next_delay) 471 { 472 int i; 473 struct ieee80211_sub_if_data *sdata; 474 struct cfg80211_scan_request *scan_req; 475 enum ieee80211_band band = local->hw.conf.chandef.chan->band; 476 u32 tx_flags; 477 478 scan_req = rcu_dereference_protected(local->scan_req, 479 lockdep_is_held(&local->mtx)); 480 481 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 482 if (scan_req->no_cck) 483 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 484 485 sdata = rcu_dereference_protected(local->scan_sdata, 486 lockdep_is_held(&local->mtx)); 487 488 for (i = 0; i < scan_req->n_ssids; i++) 489 ieee80211_send_probe_req( 490 sdata, local->scan_addr, NULL, 491 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len, 492 scan_req->ie, scan_req->ie_len, 493 scan_req->rates[band], false, 494 tx_flags, local->hw.conf.chandef.chan, true); 495 496 /* 497 * After sending probe requests, wait for probe responses 498 * on the channel. 499 */ 500 *next_delay = IEEE80211_CHANNEL_TIME; 501 local->next_scan_state = SCAN_DECISION; 502 } 503 504 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 505 struct cfg80211_scan_request *req) 506 { 507 struct ieee80211_local *local = sdata->local; 508 int rc; 509 510 lockdep_assert_held(&local->mtx); 511 512 if (local->scan_req || ieee80211_is_radar_required(local)) 513 return -EBUSY; 514 515 if (!ieee80211_can_scan(local, sdata)) { 516 /* wait for the work to finish/time out */ 517 rcu_assign_pointer(local->scan_req, req); 518 rcu_assign_pointer(local->scan_sdata, sdata); 519 return 0; 520 } 521 522 if (local->ops->hw_scan) { 523 u8 *ies; 524 525 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len; 526 527 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { 528 int i, n_bands = 0; 529 u8 bands_counted = 0; 530 531 for (i = 0; i < req->n_channels; i++) { 532 if (bands_counted & BIT(req->channels[i]->band)) 533 continue; 534 bands_counted |= BIT(req->channels[i]->band); 535 n_bands++; 536 } 537 538 local->hw_scan_ies_bufsize *= n_bands; 539 } 540 541 local->hw_scan_req = kmalloc( 542 sizeof(*local->hw_scan_req) + 543 req->n_channels * sizeof(req->channels[0]) + 544 local->hw_scan_ies_bufsize, GFP_KERNEL); 545 if (!local->hw_scan_req) 546 return -ENOMEM; 547 548 local->hw_scan_req->req.ssids = req->ssids; 549 local->hw_scan_req->req.n_ssids = req->n_ssids; 550 ies = (u8 *)local->hw_scan_req + 551 sizeof(*local->hw_scan_req) + 552 req->n_channels * sizeof(req->channels[0]); 553 local->hw_scan_req->req.ie = ies; 554 local->hw_scan_req->req.flags = req->flags; 555 556 local->hw_scan_band = 0; 557 558 /* 559 * After allocating local->hw_scan_req, we must 560 * go through until ieee80211_prep_hw_scan(), so 561 * anything that might be changed here and leave 562 * this function early must not go after this 563 * allocation. 564 */ 565 } 566 567 rcu_assign_pointer(local->scan_req, req); 568 rcu_assign_pointer(local->scan_sdata, sdata); 569 570 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR) 571 get_random_mask_addr(local->scan_addr, 572 req->mac_addr, 573 req->mac_addr_mask); 574 else 575 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN); 576 577 if (local->ops->hw_scan) { 578 __set_bit(SCAN_HW_SCANNING, &local->scanning); 579 } else if ((req->n_channels == 1) && 580 (req->channels[0] == local->_oper_chandef.chan)) { 581 /* 582 * If we are scanning only on the operating channel 583 * then we do not need to stop normal activities 584 */ 585 unsigned long next_delay; 586 587 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 588 589 ieee80211_recalc_idle(local); 590 591 /* Notify driver scan is starting, keep order of operations 592 * same as normal software scan, in case that matters. */ 593 drv_sw_scan_start(local, sdata, local->scan_addr); 594 595 ieee80211_configure_filter(local); /* accept probe-responses */ 596 597 /* We need to ensure power level is at max for scanning. */ 598 ieee80211_hw_config(local, 0); 599 600 if ((req->channels[0]->flags & 601 IEEE80211_CHAN_NO_IR) || 602 !req->n_ssids) { 603 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 604 } else { 605 ieee80211_scan_state_send_probe(local, &next_delay); 606 next_delay = IEEE80211_CHANNEL_TIME; 607 } 608 609 /* Now, just wait a bit and we are all done! */ 610 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 611 next_delay); 612 return 0; 613 } else { 614 /* Do normal software scan */ 615 __set_bit(SCAN_SW_SCANNING, &local->scanning); 616 } 617 618 ieee80211_recalc_idle(local); 619 620 if (local->ops->hw_scan) { 621 WARN_ON(!ieee80211_prep_hw_scan(local)); 622 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 623 } else { 624 rc = ieee80211_start_sw_scan(local, sdata); 625 } 626 627 if (rc) { 628 kfree(local->hw_scan_req); 629 local->hw_scan_req = NULL; 630 local->scanning = 0; 631 632 ieee80211_recalc_idle(local); 633 634 local->scan_req = NULL; 635 RCU_INIT_POINTER(local->scan_sdata, NULL); 636 } 637 638 return rc; 639 } 640 641 static unsigned long 642 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 643 { 644 /* 645 * TODO: channel switching also consumes quite some time, 646 * add that delay as well to get a better estimation 647 */ 648 if (chan->flags & IEEE80211_CHAN_NO_IR) 649 return IEEE80211_PASSIVE_CHANNEL_TIME; 650 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 651 } 652 653 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 654 unsigned long *next_delay) 655 { 656 bool associated = false; 657 bool tx_empty = true; 658 bool bad_latency; 659 struct ieee80211_sub_if_data *sdata; 660 struct ieee80211_channel *next_chan; 661 enum mac80211_scan_state next_scan_state; 662 struct cfg80211_scan_request *scan_req; 663 664 /* 665 * check if at least one STA interface is associated, 666 * check if at least one STA interface has pending tx frames 667 * and grab the lowest used beacon interval 668 */ 669 mutex_lock(&local->iflist_mtx); 670 list_for_each_entry(sdata, &local->interfaces, list) { 671 if (!ieee80211_sdata_running(sdata)) 672 continue; 673 674 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 675 if (sdata->u.mgd.associated) { 676 associated = true; 677 678 if (!qdisc_all_tx_empty(sdata->dev)) { 679 tx_empty = false; 680 break; 681 } 682 } 683 } 684 } 685 mutex_unlock(&local->iflist_mtx); 686 687 scan_req = rcu_dereference_protected(local->scan_req, 688 lockdep_is_held(&local->mtx)); 689 690 next_chan = scan_req->channels[local->scan_channel_idx]; 691 692 /* 693 * we're currently scanning a different channel, let's 694 * see if we can scan another channel without interfering 695 * with the current traffic situation. 696 * 697 * Keep good latency, do not stay off-channel more than 125 ms. 698 */ 699 700 bad_latency = time_after(jiffies + 701 ieee80211_scan_get_channel_time(next_chan), 702 local->leave_oper_channel_time + HZ / 8); 703 704 if (associated && !tx_empty) { 705 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 706 next_scan_state = SCAN_ABORT; 707 else 708 next_scan_state = SCAN_SUSPEND; 709 } else if (associated && bad_latency) { 710 next_scan_state = SCAN_SUSPEND; 711 } else { 712 next_scan_state = SCAN_SET_CHANNEL; 713 } 714 715 local->next_scan_state = next_scan_state; 716 717 *next_delay = 0; 718 } 719 720 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 721 unsigned long *next_delay) 722 { 723 int skip; 724 struct ieee80211_channel *chan; 725 enum nl80211_bss_scan_width oper_scan_width; 726 struct cfg80211_scan_request *scan_req; 727 728 scan_req = rcu_dereference_protected(local->scan_req, 729 lockdep_is_held(&local->mtx)); 730 731 skip = 0; 732 chan = scan_req->channels[local->scan_channel_idx]; 733 734 local->scan_chandef.chan = chan; 735 local->scan_chandef.center_freq1 = chan->center_freq; 736 local->scan_chandef.center_freq2 = 0; 737 switch (scan_req->scan_width) { 738 case NL80211_BSS_CHAN_WIDTH_5: 739 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 740 break; 741 case NL80211_BSS_CHAN_WIDTH_10: 742 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 743 break; 744 case NL80211_BSS_CHAN_WIDTH_20: 745 /* If scanning on oper channel, use whatever channel-type 746 * is currently in use. 747 */ 748 oper_scan_width = cfg80211_chandef_to_scan_width( 749 &local->_oper_chandef); 750 if (chan == local->_oper_chandef.chan && 751 oper_scan_width == scan_req->scan_width) 752 local->scan_chandef = local->_oper_chandef; 753 else 754 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 755 break; 756 } 757 758 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 759 skip = 1; 760 761 /* advance state machine to next channel/band */ 762 local->scan_channel_idx++; 763 764 if (skip) { 765 /* if we skip this channel return to the decision state */ 766 local->next_scan_state = SCAN_DECISION; 767 return; 768 } 769 770 /* 771 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 772 * (which unfortunately doesn't say _why_ step a) is done, 773 * but it waits for the probe delay or until a frame is 774 * received - and the received frame would update the NAV). 775 * For now, we do not support waiting until a frame is 776 * received. 777 * 778 * In any case, it is not necessary for a passive scan. 779 */ 780 if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) { 781 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 782 local->next_scan_state = SCAN_DECISION; 783 return; 784 } 785 786 /* active scan, send probes */ 787 *next_delay = IEEE80211_PROBE_DELAY; 788 local->next_scan_state = SCAN_SEND_PROBE; 789 } 790 791 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 792 unsigned long *next_delay) 793 { 794 /* switch back to the operating channel */ 795 local->scan_chandef.chan = NULL; 796 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 797 798 /* disable PS */ 799 ieee80211_offchannel_return(local); 800 801 *next_delay = HZ / 5; 802 /* afterwards, resume scan & go to next channel */ 803 local->next_scan_state = SCAN_RESUME; 804 } 805 806 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 807 unsigned long *next_delay) 808 { 809 ieee80211_offchannel_stop_vifs(local); 810 811 if (local->ops->flush) { 812 ieee80211_flush_queues(local, NULL, false); 813 *next_delay = 0; 814 } else 815 *next_delay = HZ / 10; 816 817 /* remember when we left the operating channel */ 818 local->leave_oper_channel_time = jiffies; 819 820 /* advance to the next channel to be scanned */ 821 local->next_scan_state = SCAN_SET_CHANNEL; 822 } 823 824 void ieee80211_scan_work(struct work_struct *work) 825 { 826 struct ieee80211_local *local = 827 container_of(work, struct ieee80211_local, scan_work.work); 828 struct ieee80211_sub_if_data *sdata; 829 struct cfg80211_scan_request *scan_req; 830 unsigned long next_delay = 0; 831 bool aborted; 832 833 mutex_lock(&local->mtx); 834 835 if (!ieee80211_can_run_worker(local)) { 836 aborted = true; 837 goto out_complete; 838 } 839 840 sdata = rcu_dereference_protected(local->scan_sdata, 841 lockdep_is_held(&local->mtx)); 842 scan_req = rcu_dereference_protected(local->scan_req, 843 lockdep_is_held(&local->mtx)); 844 845 /* When scanning on-channel, the first-callback means completed. */ 846 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 847 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 848 goto out_complete; 849 } 850 851 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 852 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 853 goto out_complete; 854 } 855 856 if (!sdata || !scan_req) 857 goto out; 858 859 if (!local->scanning) { 860 int rc; 861 862 RCU_INIT_POINTER(local->scan_req, NULL); 863 RCU_INIT_POINTER(local->scan_sdata, NULL); 864 865 rc = __ieee80211_start_scan(sdata, scan_req); 866 if (rc) { 867 /* need to complete scan in cfg80211 */ 868 rcu_assign_pointer(local->scan_req, scan_req); 869 aborted = true; 870 goto out_complete; 871 } else 872 goto out; 873 } 874 875 /* 876 * as long as no delay is required advance immediately 877 * without scheduling a new work 878 */ 879 do { 880 if (!ieee80211_sdata_running(sdata)) { 881 aborted = true; 882 goto out_complete; 883 } 884 885 switch (local->next_scan_state) { 886 case SCAN_DECISION: 887 /* if no more bands/channels left, complete scan */ 888 if (local->scan_channel_idx >= scan_req->n_channels) { 889 aborted = false; 890 goto out_complete; 891 } 892 ieee80211_scan_state_decision(local, &next_delay); 893 break; 894 case SCAN_SET_CHANNEL: 895 ieee80211_scan_state_set_channel(local, &next_delay); 896 break; 897 case SCAN_SEND_PROBE: 898 ieee80211_scan_state_send_probe(local, &next_delay); 899 break; 900 case SCAN_SUSPEND: 901 ieee80211_scan_state_suspend(local, &next_delay); 902 break; 903 case SCAN_RESUME: 904 ieee80211_scan_state_resume(local, &next_delay); 905 break; 906 case SCAN_ABORT: 907 aborted = true; 908 goto out_complete; 909 } 910 } while (next_delay == 0); 911 912 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 913 goto out; 914 915 out_complete: 916 __ieee80211_scan_completed(&local->hw, aborted); 917 out: 918 mutex_unlock(&local->mtx); 919 } 920 921 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 922 struct cfg80211_scan_request *req) 923 { 924 int res; 925 926 mutex_lock(&sdata->local->mtx); 927 res = __ieee80211_start_scan(sdata, req); 928 mutex_unlock(&sdata->local->mtx); 929 930 return res; 931 } 932 933 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 934 const u8 *ssid, u8 ssid_len, 935 struct ieee80211_channel **channels, 936 unsigned int n_channels, 937 enum nl80211_bss_scan_width scan_width) 938 { 939 struct ieee80211_local *local = sdata->local; 940 int ret = -EBUSY, i, n_ch = 0; 941 enum ieee80211_band band; 942 943 mutex_lock(&local->mtx); 944 945 /* busy scanning */ 946 if (local->scan_req) 947 goto unlock; 948 949 /* fill internal scan request */ 950 if (!channels) { 951 int max_n; 952 953 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 954 if (!local->hw.wiphy->bands[band]) 955 continue; 956 957 max_n = local->hw.wiphy->bands[band]->n_channels; 958 for (i = 0; i < max_n; i++) { 959 struct ieee80211_channel *tmp_ch = 960 &local->hw.wiphy->bands[band]->channels[i]; 961 962 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR | 963 IEEE80211_CHAN_DISABLED)) 964 continue; 965 966 local->int_scan_req->channels[n_ch] = tmp_ch; 967 n_ch++; 968 } 969 } 970 971 if (WARN_ON_ONCE(n_ch == 0)) 972 goto unlock; 973 974 local->int_scan_req->n_channels = n_ch; 975 } else { 976 for (i = 0; i < n_channels; i++) { 977 if (channels[i]->flags & (IEEE80211_CHAN_NO_IR | 978 IEEE80211_CHAN_DISABLED)) 979 continue; 980 981 local->int_scan_req->channels[n_ch] = channels[i]; 982 n_ch++; 983 } 984 985 if (WARN_ON_ONCE(n_ch == 0)) 986 goto unlock; 987 988 local->int_scan_req->n_channels = n_ch; 989 } 990 991 local->int_scan_req->ssids = &local->scan_ssid; 992 local->int_scan_req->n_ssids = 1; 993 local->int_scan_req->scan_width = scan_width; 994 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 995 local->int_scan_req->ssids[0].ssid_len = ssid_len; 996 997 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 998 unlock: 999 mutex_unlock(&local->mtx); 1000 return ret; 1001 } 1002 1003 /* 1004 * Only call this function when a scan can't be queued -- under RTNL. 1005 */ 1006 void ieee80211_scan_cancel(struct ieee80211_local *local) 1007 { 1008 /* 1009 * We are canceling software scan, or deferred scan that was not 1010 * yet really started (see __ieee80211_start_scan ). 1011 * 1012 * Regarding hardware scan: 1013 * - we can not call __ieee80211_scan_completed() as when 1014 * SCAN_HW_SCANNING bit is set this function change 1015 * local->hw_scan_req to operate on 5G band, what race with 1016 * driver which can use local->hw_scan_req 1017 * 1018 * - we can not cancel scan_work since driver can schedule it 1019 * by ieee80211_scan_completed(..., true) to finish scan 1020 * 1021 * Hence we only call the cancel_hw_scan() callback, but the low-level 1022 * driver is still responsible for calling ieee80211_scan_completed() 1023 * after the scan was completed/aborted. 1024 */ 1025 1026 mutex_lock(&local->mtx); 1027 if (!local->scan_req) 1028 goto out; 1029 1030 /* 1031 * We have a scan running and the driver already reported completion, 1032 * but the worker hasn't run yet or is stuck on the mutex - mark it as 1033 * cancelled. 1034 */ 1035 if (test_bit(SCAN_HW_SCANNING, &local->scanning) && 1036 test_bit(SCAN_COMPLETED, &local->scanning)) { 1037 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1038 goto out; 1039 } 1040 1041 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 1042 /* 1043 * Make sure that __ieee80211_scan_completed doesn't trigger a 1044 * scan on another band. 1045 */ 1046 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1047 if (local->ops->cancel_hw_scan) 1048 drv_cancel_hw_scan(local, 1049 rcu_dereference_protected(local->scan_sdata, 1050 lockdep_is_held(&local->mtx))); 1051 goto out; 1052 } 1053 1054 /* 1055 * If the work is currently running, it must be blocked on 1056 * the mutex, but we'll set scan_sdata = NULL and it'll 1057 * simply exit once it acquires the mutex. 1058 */ 1059 cancel_delayed_work(&local->scan_work); 1060 /* and clean up */ 1061 __ieee80211_scan_completed(&local->hw, true); 1062 out: 1063 mutex_unlock(&local->mtx); 1064 } 1065 1066 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1067 struct cfg80211_sched_scan_request *req) 1068 { 1069 struct ieee80211_local *local = sdata->local; 1070 struct ieee80211_scan_ies sched_scan_ies = {}; 1071 struct cfg80211_chan_def chandef; 1072 int ret, i, iebufsz, num_bands = 0; 1073 u32 rate_masks[IEEE80211_NUM_BANDS] = {}; 1074 u8 bands_used = 0; 1075 u8 *ie; 1076 size_t len; 1077 1078 iebufsz = local->scan_ies_len + req->ie_len; 1079 1080 lockdep_assert_held(&local->mtx); 1081 1082 if (!local->ops->sched_scan_start) 1083 return -ENOTSUPP; 1084 1085 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 1086 if (local->hw.wiphy->bands[i]) { 1087 bands_used |= BIT(i); 1088 rate_masks[i] = (u32) -1; 1089 num_bands++; 1090 } 1091 } 1092 1093 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL); 1094 if (!ie) { 1095 ret = -ENOMEM; 1096 goto out; 1097 } 1098 1099 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 1100 1101 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz, 1102 &sched_scan_ies, req->ie, 1103 req->ie_len, bands_used, 1104 rate_masks, &chandef); 1105 1106 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1107 if (ret == 0) { 1108 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1109 rcu_assign_pointer(local->sched_scan_req, req); 1110 } 1111 1112 kfree(ie); 1113 1114 out: 1115 if (ret) { 1116 /* Clean in case of failure after HW restart or upon resume. */ 1117 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1118 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1119 } 1120 1121 return ret; 1122 } 1123 1124 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1125 struct cfg80211_sched_scan_request *req) 1126 { 1127 struct ieee80211_local *local = sdata->local; 1128 int ret; 1129 1130 mutex_lock(&local->mtx); 1131 1132 if (rcu_access_pointer(local->sched_scan_sdata)) { 1133 mutex_unlock(&local->mtx); 1134 return -EBUSY; 1135 } 1136 1137 ret = __ieee80211_request_sched_scan_start(sdata, req); 1138 1139 mutex_unlock(&local->mtx); 1140 return ret; 1141 } 1142 1143 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local) 1144 { 1145 struct ieee80211_sub_if_data *sched_scan_sdata; 1146 int ret = -ENOENT; 1147 1148 mutex_lock(&local->mtx); 1149 1150 if (!local->ops->sched_scan_stop) { 1151 ret = -ENOTSUPP; 1152 goto out; 1153 } 1154 1155 /* We don't want to restart sched scan anymore. */ 1156 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1157 1158 sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata, 1159 lockdep_is_held(&local->mtx)); 1160 if (sched_scan_sdata) { 1161 ret = drv_sched_scan_stop(local, sched_scan_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