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 .boottime_ns = rx_status->boottime_ns, 71 }; 72 bool signal_valid; 73 74 if (ieee80211_hw_check(&local->hw, SIGNAL_DBM)) 75 bss_meta.signal = rx_status->signal * 100; 76 else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC)) 77 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal; 78 79 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20; 80 if (rx_status->flag & RX_FLAG_5MHZ) 81 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5; 82 if (rx_status->flag & RX_FLAG_10MHZ) 83 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10; 84 85 bss_meta.chan = channel; 86 cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta, 87 mgmt, len, 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 == NUM_NL80211_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 ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid); 309 310 return true; 311 } 312 313 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 314 { 315 struct ieee80211_local *local = hw_to_local(hw); 316 bool hw_scan = local->ops->hw_scan; 317 bool was_scanning = local->scanning; 318 struct cfg80211_scan_request *scan_req; 319 struct ieee80211_sub_if_data *scan_sdata; 320 struct ieee80211_sub_if_data *sdata; 321 322 lockdep_assert_held(&local->mtx); 323 324 /* 325 * It's ok to abort a not-yet-running scan (that 326 * we have one at all will be verified by checking 327 * local->scan_req next), but not to complete it 328 * successfully. 329 */ 330 if (WARN_ON(!local->scanning && !aborted)) 331 aborted = true; 332 333 if (WARN_ON(!local->scan_req)) 334 return; 335 336 if (hw_scan && !aborted && 337 !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) && 338 ieee80211_prep_hw_scan(local)) { 339 int rc; 340 341 rc = drv_hw_scan(local, 342 rcu_dereference_protected(local->scan_sdata, 343 lockdep_is_held(&local->mtx)), 344 local->hw_scan_req); 345 346 if (rc == 0) 347 return; 348 } 349 350 kfree(local->hw_scan_req); 351 local->hw_scan_req = NULL; 352 353 scan_req = rcu_dereference_protected(local->scan_req, 354 lockdep_is_held(&local->mtx)); 355 356 if (scan_req != local->int_scan_req) 357 cfg80211_scan_done(scan_req, aborted); 358 RCU_INIT_POINTER(local->scan_req, NULL); 359 360 scan_sdata = rcu_dereference_protected(local->scan_sdata, 361 lockdep_is_held(&local->mtx)); 362 RCU_INIT_POINTER(local->scan_sdata, NULL); 363 364 local->scanning = 0; 365 local->scan_chandef.chan = NULL; 366 367 /* Set power back to normal operating levels. */ 368 ieee80211_hw_config(local, 0); 369 370 if (!hw_scan) { 371 ieee80211_configure_filter(local); 372 drv_sw_scan_complete(local, scan_sdata); 373 ieee80211_offchannel_return(local); 374 } 375 376 ieee80211_recalc_idle(local); 377 378 ieee80211_mlme_notify_scan_completed(local); 379 ieee80211_ibss_notify_scan_completed(local); 380 381 /* Requeue all the work that might have been ignored while 382 * the scan was in progress; if there was none this will 383 * just be a no-op for the particular interface. 384 */ 385 list_for_each_entry_rcu(sdata, &local->interfaces, list) { 386 if (ieee80211_sdata_running(sdata)) 387 ieee80211_queue_work(&sdata->local->hw, &sdata->work); 388 } 389 390 if (was_scanning) 391 ieee80211_start_next_roc(local); 392 } 393 394 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 395 { 396 struct ieee80211_local *local = hw_to_local(hw); 397 398 trace_api_scan_completed(local, aborted); 399 400 set_bit(SCAN_COMPLETED, &local->scanning); 401 if (aborted) 402 set_bit(SCAN_ABORTED, &local->scanning); 403 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 404 } 405 EXPORT_SYMBOL(ieee80211_scan_completed); 406 407 static int ieee80211_start_sw_scan(struct ieee80211_local *local, 408 struct ieee80211_sub_if_data *sdata) 409 { 410 /* Software scan is not supported in multi-channel cases */ 411 if (local->use_chanctx) 412 return -EOPNOTSUPP; 413 414 /* 415 * Hardware/driver doesn't support hw_scan, so use software 416 * scanning instead. First send a nullfunc frame with power save 417 * bit on so that AP will buffer the frames for us while we are not 418 * listening, then send probe requests to each channel and wait for 419 * the responses. After all channels are scanned, tune back to the 420 * original channel and send a nullfunc frame with power save bit 421 * off to trigger the AP to send us all the buffered frames. 422 * 423 * Note that while local->sw_scanning is true everything else but 424 * nullfunc frames and probe requests will be dropped in 425 * ieee80211_tx_h_check_assoc(). 426 */ 427 drv_sw_scan_start(local, sdata, local->scan_addr); 428 429 local->leave_oper_channel_time = jiffies; 430 local->next_scan_state = SCAN_DECISION; 431 local->scan_channel_idx = 0; 432 433 ieee80211_offchannel_stop_vifs(local); 434 435 /* ensure nullfunc is transmitted before leaving operating channel */ 436 ieee80211_flush_queues(local, NULL, false); 437 438 ieee80211_configure_filter(local); 439 440 /* We need to set power level at maximum rate for scanning. */ 441 ieee80211_hw_config(local, 0); 442 443 ieee80211_queue_delayed_work(&local->hw, 444 &local->scan_work, 0); 445 446 return 0; 447 } 448 449 static bool ieee80211_can_scan(struct ieee80211_local *local, 450 struct ieee80211_sub_if_data *sdata) 451 { 452 if (ieee80211_is_radar_required(local)) 453 return false; 454 455 if (!list_empty(&local->roc_list)) 456 return false; 457 458 if (sdata->vif.type == NL80211_IFTYPE_STATION && 459 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL) 460 return false; 461 462 return true; 463 } 464 465 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 466 { 467 lockdep_assert_held(&local->mtx); 468 469 if (!local->scan_req || local->scanning) 470 return; 471 472 if (!ieee80211_can_scan(local, 473 rcu_dereference_protected( 474 local->scan_sdata, 475 lockdep_is_held(&local->mtx)))) 476 return; 477 478 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 479 round_jiffies_relative(0)); 480 } 481 482 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 483 unsigned long *next_delay) 484 { 485 int i; 486 struct ieee80211_sub_if_data *sdata; 487 struct cfg80211_scan_request *scan_req; 488 enum nl80211_band band = local->hw.conf.chandef.chan->band; 489 u32 tx_flags; 490 491 scan_req = rcu_dereference_protected(local->scan_req, 492 lockdep_is_held(&local->mtx)); 493 494 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 495 if (scan_req->no_cck) 496 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 497 498 sdata = rcu_dereference_protected(local->scan_sdata, 499 lockdep_is_held(&local->mtx)); 500 501 for (i = 0; i < scan_req->n_ssids; i++) 502 ieee80211_send_probe_req( 503 sdata, local->scan_addr, scan_req->bssid, 504 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len, 505 scan_req->ie, scan_req->ie_len, 506 scan_req->rates[band], false, 507 tx_flags, local->hw.conf.chandef.chan, true); 508 509 /* 510 * After sending probe requests, wait for probe responses 511 * on the channel. 512 */ 513 *next_delay = IEEE80211_CHANNEL_TIME; 514 local->next_scan_state = SCAN_DECISION; 515 } 516 517 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 518 struct cfg80211_scan_request *req) 519 { 520 struct ieee80211_local *local = sdata->local; 521 int rc; 522 523 lockdep_assert_held(&local->mtx); 524 525 if (local->scan_req || ieee80211_is_radar_required(local)) 526 return -EBUSY; 527 528 if (!ieee80211_can_scan(local, sdata)) { 529 /* wait for the work to finish/time out */ 530 rcu_assign_pointer(local->scan_req, req); 531 rcu_assign_pointer(local->scan_sdata, sdata); 532 return 0; 533 } 534 535 if (local->ops->hw_scan) { 536 u8 *ies; 537 538 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len; 539 540 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { 541 int i, n_bands = 0; 542 u8 bands_counted = 0; 543 544 for (i = 0; i < req->n_channels; i++) { 545 if (bands_counted & BIT(req->channels[i]->band)) 546 continue; 547 bands_counted |= BIT(req->channels[i]->band); 548 n_bands++; 549 } 550 551 local->hw_scan_ies_bufsize *= n_bands; 552 } 553 554 local->hw_scan_req = kmalloc( 555 sizeof(*local->hw_scan_req) + 556 req->n_channels * sizeof(req->channels[0]) + 557 local->hw_scan_ies_bufsize, GFP_KERNEL); 558 if (!local->hw_scan_req) 559 return -ENOMEM; 560 561 local->hw_scan_req->req.ssids = req->ssids; 562 local->hw_scan_req->req.n_ssids = req->n_ssids; 563 ies = (u8 *)local->hw_scan_req + 564 sizeof(*local->hw_scan_req) + 565 req->n_channels * sizeof(req->channels[0]); 566 local->hw_scan_req->req.ie = ies; 567 local->hw_scan_req->req.flags = req->flags; 568 eth_broadcast_addr(local->hw_scan_req->req.bssid); 569 570 local->hw_scan_band = 0; 571 572 /* 573 * After allocating local->hw_scan_req, we must 574 * go through until ieee80211_prep_hw_scan(), so 575 * anything that might be changed here and leave 576 * this function early must not go after this 577 * allocation. 578 */ 579 } 580 581 rcu_assign_pointer(local->scan_req, req); 582 rcu_assign_pointer(local->scan_sdata, sdata); 583 584 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR) 585 get_random_mask_addr(local->scan_addr, 586 req->mac_addr, 587 req->mac_addr_mask); 588 else 589 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN); 590 591 if (local->ops->hw_scan) { 592 __set_bit(SCAN_HW_SCANNING, &local->scanning); 593 } else if ((req->n_channels == 1) && 594 (req->channels[0] == local->_oper_chandef.chan)) { 595 /* 596 * If we are scanning only on the operating channel 597 * then we do not need to stop normal activities 598 */ 599 unsigned long next_delay; 600 601 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 602 603 ieee80211_recalc_idle(local); 604 605 /* Notify driver scan is starting, keep order of operations 606 * same as normal software scan, in case that matters. */ 607 drv_sw_scan_start(local, sdata, local->scan_addr); 608 609 ieee80211_configure_filter(local); /* accept probe-responses */ 610 611 /* We need to ensure power level is at max for scanning. */ 612 ieee80211_hw_config(local, 0); 613 614 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR | 615 IEEE80211_CHAN_RADAR)) || 616 !req->n_ssids) { 617 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 618 } else { 619 ieee80211_scan_state_send_probe(local, &next_delay); 620 next_delay = IEEE80211_CHANNEL_TIME; 621 } 622 623 /* Now, just wait a bit and we are all done! */ 624 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 625 next_delay); 626 return 0; 627 } else { 628 /* Do normal software scan */ 629 __set_bit(SCAN_SW_SCANNING, &local->scanning); 630 } 631 632 ieee80211_recalc_idle(local); 633 634 if (local->ops->hw_scan) { 635 WARN_ON(!ieee80211_prep_hw_scan(local)); 636 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 637 } else { 638 rc = ieee80211_start_sw_scan(local, sdata); 639 } 640 641 if (rc) { 642 kfree(local->hw_scan_req); 643 local->hw_scan_req = NULL; 644 local->scanning = 0; 645 646 ieee80211_recalc_idle(local); 647 648 local->scan_req = NULL; 649 RCU_INIT_POINTER(local->scan_sdata, NULL); 650 } 651 652 return rc; 653 } 654 655 static unsigned long 656 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 657 { 658 /* 659 * TODO: channel switching also consumes quite some time, 660 * add that delay as well to get a better estimation 661 */ 662 if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) 663 return IEEE80211_PASSIVE_CHANNEL_TIME; 664 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 665 } 666 667 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 668 unsigned long *next_delay) 669 { 670 bool associated = false; 671 bool tx_empty = true; 672 bool bad_latency; 673 struct ieee80211_sub_if_data *sdata; 674 struct ieee80211_channel *next_chan; 675 enum mac80211_scan_state next_scan_state; 676 struct cfg80211_scan_request *scan_req; 677 678 /* 679 * check if at least one STA interface is associated, 680 * check if at least one STA interface has pending tx frames 681 * and grab the lowest used beacon interval 682 */ 683 mutex_lock(&local->iflist_mtx); 684 list_for_each_entry(sdata, &local->interfaces, list) { 685 if (!ieee80211_sdata_running(sdata)) 686 continue; 687 688 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 689 if (sdata->u.mgd.associated) { 690 associated = true; 691 692 if (!qdisc_all_tx_empty(sdata->dev)) { 693 tx_empty = false; 694 break; 695 } 696 } 697 } 698 } 699 mutex_unlock(&local->iflist_mtx); 700 701 scan_req = rcu_dereference_protected(local->scan_req, 702 lockdep_is_held(&local->mtx)); 703 704 next_chan = scan_req->channels[local->scan_channel_idx]; 705 706 /* 707 * we're currently scanning a different channel, let's 708 * see if we can scan another channel without interfering 709 * with the current traffic situation. 710 * 711 * Keep good latency, do not stay off-channel more than 125 ms. 712 */ 713 714 bad_latency = time_after(jiffies + 715 ieee80211_scan_get_channel_time(next_chan), 716 local->leave_oper_channel_time + HZ / 8); 717 718 if (associated && !tx_empty) { 719 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 720 next_scan_state = SCAN_ABORT; 721 else 722 next_scan_state = SCAN_SUSPEND; 723 } else if (associated && bad_latency) { 724 next_scan_state = SCAN_SUSPEND; 725 } else { 726 next_scan_state = SCAN_SET_CHANNEL; 727 } 728 729 local->next_scan_state = next_scan_state; 730 731 *next_delay = 0; 732 } 733 734 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 735 unsigned long *next_delay) 736 { 737 int skip; 738 struct ieee80211_channel *chan; 739 enum nl80211_bss_scan_width oper_scan_width; 740 struct cfg80211_scan_request *scan_req; 741 742 scan_req = rcu_dereference_protected(local->scan_req, 743 lockdep_is_held(&local->mtx)); 744 745 skip = 0; 746 chan = scan_req->channels[local->scan_channel_idx]; 747 748 local->scan_chandef.chan = chan; 749 local->scan_chandef.center_freq1 = chan->center_freq; 750 local->scan_chandef.center_freq2 = 0; 751 switch (scan_req->scan_width) { 752 case NL80211_BSS_CHAN_WIDTH_5: 753 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 754 break; 755 case NL80211_BSS_CHAN_WIDTH_10: 756 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 757 break; 758 case NL80211_BSS_CHAN_WIDTH_20: 759 /* If scanning on oper channel, use whatever channel-type 760 * is currently in use. 761 */ 762 oper_scan_width = cfg80211_chandef_to_scan_width( 763 &local->_oper_chandef); 764 if (chan == local->_oper_chandef.chan && 765 oper_scan_width == scan_req->scan_width) 766 local->scan_chandef = local->_oper_chandef; 767 else 768 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 769 break; 770 } 771 772 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 773 skip = 1; 774 775 /* advance state machine to next channel/band */ 776 local->scan_channel_idx++; 777 778 if (skip) { 779 /* if we skip this channel return to the decision state */ 780 local->next_scan_state = SCAN_DECISION; 781 return; 782 } 783 784 /* 785 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 786 * (which unfortunately doesn't say _why_ step a) is done, 787 * but it waits for the probe delay or until a frame is 788 * received - and the received frame would update the NAV). 789 * For now, we do not support waiting until a frame is 790 * received. 791 * 792 * In any case, it is not necessary for a passive scan. 793 */ 794 if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) || 795 !scan_req->n_ssids) { 796 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 797 local->next_scan_state = SCAN_DECISION; 798 return; 799 } 800 801 /* active scan, send probes */ 802 *next_delay = IEEE80211_PROBE_DELAY; 803 local->next_scan_state = SCAN_SEND_PROBE; 804 } 805 806 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 807 unsigned long *next_delay) 808 { 809 /* switch back to the operating channel */ 810 local->scan_chandef.chan = NULL; 811 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 812 813 /* disable PS */ 814 ieee80211_offchannel_return(local); 815 816 *next_delay = HZ / 5; 817 /* afterwards, resume scan & go to next channel */ 818 local->next_scan_state = SCAN_RESUME; 819 } 820 821 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 822 unsigned long *next_delay) 823 { 824 ieee80211_offchannel_stop_vifs(local); 825 826 if (local->ops->flush) { 827 ieee80211_flush_queues(local, NULL, false); 828 *next_delay = 0; 829 } else 830 *next_delay = HZ / 10; 831 832 /* remember when we left the operating channel */ 833 local->leave_oper_channel_time = jiffies; 834 835 /* advance to the next channel to be scanned */ 836 local->next_scan_state = SCAN_SET_CHANNEL; 837 } 838 839 void ieee80211_scan_work(struct work_struct *work) 840 { 841 struct ieee80211_local *local = 842 container_of(work, struct ieee80211_local, scan_work.work); 843 struct ieee80211_sub_if_data *sdata; 844 struct cfg80211_scan_request *scan_req; 845 unsigned long next_delay = 0; 846 bool aborted; 847 848 mutex_lock(&local->mtx); 849 850 if (!ieee80211_can_run_worker(local)) { 851 aborted = true; 852 goto out_complete; 853 } 854 855 sdata = rcu_dereference_protected(local->scan_sdata, 856 lockdep_is_held(&local->mtx)); 857 scan_req = rcu_dereference_protected(local->scan_req, 858 lockdep_is_held(&local->mtx)); 859 860 /* When scanning on-channel, the first-callback means completed. */ 861 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 862 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 863 goto out_complete; 864 } 865 866 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 867 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 868 goto out_complete; 869 } 870 871 if (!sdata || !scan_req) 872 goto out; 873 874 if (!local->scanning) { 875 int rc; 876 877 RCU_INIT_POINTER(local->scan_req, NULL); 878 RCU_INIT_POINTER(local->scan_sdata, NULL); 879 880 rc = __ieee80211_start_scan(sdata, scan_req); 881 if (rc) { 882 /* need to complete scan in cfg80211 */ 883 rcu_assign_pointer(local->scan_req, scan_req); 884 aborted = true; 885 goto out_complete; 886 } else 887 goto out; 888 } 889 890 /* 891 * as long as no delay is required advance immediately 892 * without scheduling a new work 893 */ 894 do { 895 if (!ieee80211_sdata_running(sdata)) { 896 aborted = true; 897 goto out_complete; 898 } 899 900 switch (local->next_scan_state) { 901 case SCAN_DECISION: 902 /* if no more bands/channels left, complete scan */ 903 if (local->scan_channel_idx >= scan_req->n_channels) { 904 aborted = false; 905 goto out_complete; 906 } 907 ieee80211_scan_state_decision(local, &next_delay); 908 break; 909 case SCAN_SET_CHANNEL: 910 ieee80211_scan_state_set_channel(local, &next_delay); 911 break; 912 case SCAN_SEND_PROBE: 913 ieee80211_scan_state_send_probe(local, &next_delay); 914 break; 915 case SCAN_SUSPEND: 916 ieee80211_scan_state_suspend(local, &next_delay); 917 break; 918 case SCAN_RESUME: 919 ieee80211_scan_state_resume(local, &next_delay); 920 break; 921 case SCAN_ABORT: 922 aborted = true; 923 goto out_complete; 924 } 925 } while (next_delay == 0); 926 927 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 928 goto out; 929 930 out_complete: 931 __ieee80211_scan_completed(&local->hw, aborted); 932 out: 933 mutex_unlock(&local->mtx); 934 } 935 936 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 937 struct cfg80211_scan_request *req) 938 { 939 int res; 940 941 mutex_lock(&sdata->local->mtx); 942 res = __ieee80211_start_scan(sdata, req); 943 mutex_unlock(&sdata->local->mtx); 944 945 return res; 946 } 947 948 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 949 const u8 *ssid, u8 ssid_len, 950 struct ieee80211_channel **channels, 951 unsigned int n_channels, 952 enum nl80211_bss_scan_width scan_width) 953 { 954 struct ieee80211_local *local = sdata->local; 955 int ret = -EBUSY, i, n_ch = 0; 956 enum nl80211_band band; 957 958 mutex_lock(&local->mtx); 959 960 /* busy scanning */ 961 if (local->scan_req) 962 goto unlock; 963 964 /* fill internal scan request */ 965 if (!channels) { 966 int max_n; 967 968 for (band = 0; band < NUM_NL80211_BANDS; band++) { 969 if (!local->hw.wiphy->bands[band]) 970 continue; 971 972 max_n = local->hw.wiphy->bands[band]->n_channels; 973 for (i = 0; i < max_n; i++) { 974 struct ieee80211_channel *tmp_ch = 975 &local->hw.wiphy->bands[band]->channels[i]; 976 977 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR | 978 IEEE80211_CHAN_DISABLED)) 979 continue; 980 981 local->int_scan_req->channels[n_ch] = tmp_ch; 982 n_ch++; 983 } 984 } 985 986 if (WARN_ON_ONCE(n_ch == 0)) 987 goto unlock; 988 989 local->int_scan_req->n_channels = n_ch; 990 } else { 991 for (i = 0; i < n_channels; i++) { 992 if (channels[i]->flags & (IEEE80211_CHAN_NO_IR | 993 IEEE80211_CHAN_DISABLED)) 994 continue; 995 996 local->int_scan_req->channels[n_ch] = channels[i]; 997 n_ch++; 998 } 999 1000 if (WARN_ON_ONCE(n_ch == 0)) 1001 goto unlock; 1002 1003 local->int_scan_req->n_channels = n_ch; 1004 } 1005 1006 local->int_scan_req->ssids = &local->scan_ssid; 1007 local->int_scan_req->n_ssids = 1; 1008 local->int_scan_req->scan_width = scan_width; 1009 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 1010 local->int_scan_req->ssids[0].ssid_len = ssid_len; 1011 1012 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 1013 unlock: 1014 mutex_unlock(&local->mtx); 1015 return ret; 1016 } 1017 1018 /* 1019 * Only call this function when a scan can't be queued -- under RTNL. 1020 */ 1021 void ieee80211_scan_cancel(struct ieee80211_local *local) 1022 { 1023 /* 1024 * We are canceling software scan, or deferred scan that was not 1025 * yet really started (see __ieee80211_start_scan ). 1026 * 1027 * Regarding hardware scan: 1028 * - we can not call __ieee80211_scan_completed() as when 1029 * SCAN_HW_SCANNING bit is set this function change 1030 * local->hw_scan_req to operate on 5G band, what race with 1031 * driver which can use local->hw_scan_req 1032 * 1033 * - we can not cancel scan_work since driver can schedule it 1034 * by ieee80211_scan_completed(..., true) to finish scan 1035 * 1036 * Hence we only call the cancel_hw_scan() callback, but the low-level 1037 * driver is still responsible for calling ieee80211_scan_completed() 1038 * after the scan was completed/aborted. 1039 */ 1040 1041 mutex_lock(&local->mtx); 1042 if (!local->scan_req) 1043 goto out; 1044 1045 /* 1046 * We have a scan running and the driver already reported completion, 1047 * but the worker hasn't run yet or is stuck on the mutex - mark it as 1048 * cancelled. 1049 */ 1050 if (test_bit(SCAN_HW_SCANNING, &local->scanning) && 1051 test_bit(SCAN_COMPLETED, &local->scanning)) { 1052 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1053 goto out; 1054 } 1055 1056 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 1057 /* 1058 * Make sure that __ieee80211_scan_completed doesn't trigger a 1059 * scan on another band. 1060 */ 1061 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1062 if (local->ops->cancel_hw_scan) 1063 drv_cancel_hw_scan(local, 1064 rcu_dereference_protected(local->scan_sdata, 1065 lockdep_is_held(&local->mtx))); 1066 goto out; 1067 } 1068 1069 /* 1070 * If the work is currently running, it must be blocked on 1071 * the mutex, but we'll set scan_sdata = NULL and it'll 1072 * simply exit once it acquires the mutex. 1073 */ 1074 cancel_delayed_work(&local->scan_work); 1075 /* and clean up */ 1076 __ieee80211_scan_completed(&local->hw, true); 1077 out: 1078 mutex_unlock(&local->mtx); 1079 } 1080 1081 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1082 struct cfg80211_sched_scan_request *req) 1083 { 1084 struct ieee80211_local *local = sdata->local; 1085 struct ieee80211_scan_ies sched_scan_ies = {}; 1086 struct cfg80211_chan_def chandef; 1087 int ret, i, iebufsz, num_bands = 0; 1088 u32 rate_masks[NUM_NL80211_BANDS] = {}; 1089 u8 bands_used = 0; 1090 u8 *ie; 1091 size_t len; 1092 1093 iebufsz = local->scan_ies_len + req->ie_len; 1094 1095 lockdep_assert_held(&local->mtx); 1096 1097 if (!local->ops->sched_scan_start) 1098 return -ENOTSUPP; 1099 1100 for (i = 0; i < NUM_NL80211_BANDS; i++) { 1101 if (local->hw.wiphy->bands[i]) { 1102 bands_used |= BIT(i); 1103 rate_masks[i] = (u32) -1; 1104 num_bands++; 1105 } 1106 } 1107 1108 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL); 1109 if (!ie) { 1110 ret = -ENOMEM; 1111 goto out; 1112 } 1113 1114 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 1115 1116 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz, 1117 &sched_scan_ies, req->ie, 1118 req->ie_len, bands_used, 1119 rate_masks, &chandef); 1120 1121 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1122 if (ret == 0) { 1123 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1124 rcu_assign_pointer(local->sched_scan_req, req); 1125 } 1126 1127 kfree(ie); 1128 1129 out: 1130 if (ret) { 1131 /* Clean in case of failure after HW restart or upon resume. */ 1132 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1133 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1134 } 1135 1136 return ret; 1137 } 1138 1139 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1140 struct cfg80211_sched_scan_request *req) 1141 { 1142 struct ieee80211_local *local = sdata->local; 1143 int ret; 1144 1145 mutex_lock(&local->mtx); 1146 1147 if (rcu_access_pointer(local->sched_scan_sdata)) { 1148 mutex_unlock(&local->mtx); 1149 return -EBUSY; 1150 } 1151 1152 ret = __ieee80211_request_sched_scan_start(sdata, req); 1153 1154 mutex_unlock(&local->mtx); 1155 return ret; 1156 } 1157 1158 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local) 1159 { 1160 struct ieee80211_sub_if_data *sched_scan_sdata; 1161 int ret = -ENOENT; 1162 1163 mutex_lock(&local->mtx); 1164 1165 if (!local->ops->sched_scan_stop) { 1166 ret = -ENOTSUPP; 1167 goto out; 1168 } 1169 1170 /* We don't want to restart sched scan anymore. */ 1171 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1172 1173 sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata, 1174 lockdep_is_held(&local->mtx)); 1175 if (sched_scan_sdata) { 1176 ret = drv_sched_scan_stop(local, sched_scan_sdata); 1177 if (!ret) 1178 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1179 } 1180 out: 1181 mutex_unlock(&local->mtx); 1182 1183 return ret; 1184 } 1185 1186 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1187 { 1188 struct ieee80211_local *local = hw_to_local(hw); 1189 1190 trace_api_sched_scan_results(local); 1191 1192 cfg80211_sched_scan_results(hw->wiphy); 1193 } 1194 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1195 1196 void ieee80211_sched_scan_end(struct ieee80211_local *local) 1197 { 1198 mutex_lock(&local->mtx); 1199 1200 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1201 mutex_unlock(&local->mtx); 1202 return; 1203 } 1204 1205 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1206 1207 /* If sched scan was aborted by the driver. */ 1208 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1209 1210 mutex_unlock(&local->mtx); 1211 1212 cfg80211_sched_scan_stopped(local->hw.wiphy); 1213 } 1214 1215 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1216 { 1217 struct ieee80211_local *local = 1218 container_of(work, struct ieee80211_local, 1219 sched_scan_stopped_work); 1220 1221 ieee80211_sched_scan_end(local); 1222 } 1223 1224 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1225 { 1226 struct ieee80211_local *local = hw_to_local(hw); 1227 1228 trace_api_sched_scan_stopped(local); 1229 1230 /* 1231 * this shouldn't really happen, so for simplicity 1232 * simply ignore it, and let mac80211 reconfigure 1233 * the sched scan later on. 1234 */ 1235 if (local->in_reconfig) 1236 return; 1237 1238 schedule_work(&local->sched_scan_stopped_work); 1239 } 1240 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1241