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 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14 15 #include <linux/if_arp.h> 16 #include <linux/etherdevice.h> 17 #include <linux/rtnetlink.h> 18 #include <linux/pm_qos.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 enum nl80211_bss_scan_width scan_width; 70 s32 signal = 0; 71 72 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) 73 signal = rx_status->signal * 100; 74 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) 75 signal = (rx_status->signal * 100) / local->hw.max_signal; 76 77 scan_width = NL80211_BSS_CHAN_WIDTH_20; 78 if (rx_status->flag & RX_FLAG_5MHZ) 79 scan_width = NL80211_BSS_CHAN_WIDTH_5; 80 if (rx_status->flag & RX_FLAG_10MHZ) 81 scan_width = NL80211_BSS_CHAN_WIDTH_10; 82 83 cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel, 84 scan_width, mgmt, len, signal, 85 GFP_ATOMIC); 86 if (!cbss) 87 return NULL; 88 89 bss = (void *)cbss->priv; 90 91 if (beacon) 92 bss->device_ts_beacon = rx_status->device_timestamp; 93 else 94 bss->device_ts_presp = rx_status->device_timestamp; 95 96 if (elems->parse_error) { 97 if (beacon) 98 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; 99 else 100 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; 101 } else { 102 if (beacon) 103 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; 104 else 105 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; 106 } 107 108 /* save the ERP value so that it is available at association time */ 109 if (elems->erp_info && (!elems->parse_error || 110 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { 111 bss->erp_value = elems->erp_info[0]; 112 bss->has_erp_value = true; 113 if (!elems->parse_error) 114 bss->valid_data |= IEEE80211_BSS_VALID_ERP; 115 } 116 117 /* replace old supported rates if we get new values */ 118 if (!elems->parse_error || 119 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { 120 srlen = 0; 121 if (elems->supp_rates) { 122 clen = IEEE80211_MAX_SUPP_RATES; 123 if (clen > elems->supp_rates_len) 124 clen = elems->supp_rates_len; 125 memcpy(bss->supp_rates, elems->supp_rates, clen); 126 srlen += clen; 127 } 128 if (elems->ext_supp_rates) { 129 clen = IEEE80211_MAX_SUPP_RATES - srlen; 130 if (clen > elems->ext_supp_rates_len) 131 clen = elems->ext_supp_rates_len; 132 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, 133 clen); 134 srlen += clen; 135 } 136 if (srlen) { 137 bss->supp_rates_len = srlen; 138 if (!elems->parse_error) 139 bss->valid_data |= IEEE80211_BSS_VALID_RATES; 140 } 141 } 142 143 if (!elems->parse_error || 144 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { 145 bss->wmm_used = elems->wmm_param || elems->wmm_info; 146 bss->uapsd_supported = is_uapsd_supported(elems); 147 if (!elems->parse_error) 148 bss->valid_data |= IEEE80211_BSS_VALID_WMM; 149 } 150 151 if (beacon) { 152 struct ieee80211_supported_band *sband = 153 local->hw.wiphy->bands[rx_status->band]; 154 if (!(rx_status->flag & RX_FLAG_HT) && 155 !(rx_status->flag & RX_FLAG_VHT)) 156 bss->beacon_rate = 157 &sband->bitrates[rx_status->rate_idx]; 158 } 159 160 return bss; 161 } 162 163 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) 164 { 165 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); 166 struct ieee80211_sub_if_data *sdata1, *sdata2; 167 struct ieee80211_mgmt *mgmt = (void *)skb->data; 168 struct ieee80211_bss *bss; 169 u8 *elements; 170 struct ieee80211_channel *channel; 171 size_t baselen; 172 struct ieee802_11_elems elems; 173 174 if (skb->len < 24 || 175 (!ieee80211_is_probe_resp(mgmt->frame_control) && 176 !ieee80211_is_beacon(mgmt->frame_control))) 177 return; 178 179 sdata1 = rcu_dereference(local->scan_sdata); 180 sdata2 = rcu_dereference(local->sched_scan_sdata); 181 182 if (likely(!sdata1 && !sdata2)) 183 return; 184 185 if (ieee80211_is_probe_resp(mgmt->frame_control)) { 186 /* ignore ProbeResp to foreign address */ 187 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) && 188 (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr))) 189 return; 190 191 elements = mgmt->u.probe_resp.variable; 192 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 193 } else { 194 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 195 elements = mgmt->u.beacon.variable; 196 } 197 198 if (baselen > skb->len) 199 return; 200 201 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems); 202 203 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); 204 205 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 206 return; 207 208 bss = ieee80211_bss_info_update(local, rx_status, 209 mgmt, skb->len, &elems, 210 channel); 211 if (bss) 212 ieee80211_rx_bss_put(local, bss); 213 } 214 215 static void 216 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef, 217 enum nl80211_bss_scan_width scan_width) 218 { 219 memset(chandef, 0, sizeof(*chandef)); 220 switch (scan_width) { 221 case NL80211_BSS_CHAN_WIDTH_5: 222 chandef->width = NL80211_CHAN_WIDTH_5; 223 break; 224 case NL80211_BSS_CHAN_WIDTH_10: 225 chandef->width = NL80211_CHAN_WIDTH_10; 226 break; 227 default: 228 chandef->width = NL80211_CHAN_WIDTH_20_NOHT; 229 break; 230 } 231 } 232 233 /* return false if no more work */ 234 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 235 { 236 struct cfg80211_scan_request *req = local->scan_req; 237 struct cfg80211_chan_def chandef; 238 enum ieee80211_band band; 239 int i, ielen, n_chans; 240 241 do { 242 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 243 return false; 244 245 band = local->hw_scan_band; 246 n_chans = 0; 247 for (i = 0; i < req->n_channels; i++) { 248 if (req->channels[i]->band == band) { 249 local->hw_scan_req->channels[n_chans] = 250 req->channels[i]; 251 n_chans++; 252 } 253 } 254 255 local->hw_scan_band++; 256 } while (!n_chans); 257 258 local->hw_scan_req->n_channels = n_chans; 259 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 260 261 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie, 262 local->hw_scan_ies_bufsize, 263 req->ie, req->ie_len, band, 264 req->rates[band], &chandef); 265 local->hw_scan_req->ie_len = ielen; 266 local->hw_scan_req->no_cck = req->no_cck; 267 268 return true; 269 } 270 271 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted, 272 bool was_hw_scan) 273 { 274 struct ieee80211_local *local = hw_to_local(hw); 275 276 lockdep_assert_held(&local->mtx); 277 278 /* 279 * It's ok to abort a not-yet-running scan (that 280 * we have one at all will be verified by checking 281 * local->scan_req next), but not to complete it 282 * successfully. 283 */ 284 if (WARN_ON(!local->scanning && !aborted)) 285 aborted = true; 286 287 if (WARN_ON(!local->scan_req)) 288 return; 289 290 if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { 291 int rc; 292 293 rc = drv_hw_scan(local, 294 rcu_dereference_protected(local->scan_sdata, 295 lockdep_is_held(&local->mtx)), 296 local->hw_scan_req); 297 298 if (rc == 0) 299 return; 300 } 301 302 kfree(local->hw_scan_req); 303 local->hw_scan_req = NULL; 304 305 if (local->scan_req != local->int_scan_req) 306 cfg80211_scan_done(local->scan_req, aborted); 307 local->scan_req = NULL; 308 rcu_assign_pointer(local->scan_sdata, NULL); 309 310 local->scanning = 0; 311 local->scan_chandef.chan = NULL; 312 313 /* Set power back to normal operating levels. */ 314 ieee80211_hw_config(local, 0); 315 316 if (!was_hw_scan) { 317 ieee80211_configure_filter(local); 318 drv_sw_scan_complete(local); 319 ieee80211_offchannel_return(local); 320 } 321 322 ieee80211_recalc_idle(local); 323 324 ieee80211_mlme_notify_scan_completed(local); 325 ieee80211_ibss_notify_scan_completed(local); 326 ieee80211_mesh_notify_scan_completed(local); 327 ieee80211_start_next_roc(local); 328 } 329 330 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 331 { 332 struct ieee80211_local *local = hw_to_local(hw); 333 334 trace_api_scan_completed(local, aborted); 335 336 set_bit(SCAN_COMPLETED, &local->scanning); 337 if (aborted) 338 set_bit(SCAN_ABORTED, &local->scanning); 339 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 340 } 341 EXPORT_SYMBOL(ieee80211_scan_completed); 342 343 static int ieee80211_start_sw_scan(struct ieee80211_local *local) 344 { 345 /* Software scan is not supported in multi-channel cases */ 346 if (local->use_chanctx) 347 return -EOPNOTSUPP; 348 349 /* 350 * Hardware/driver doesn't support hw_scan, so use software 351 * scanning instead. First send a nullfunc frame with power save 352 * bit on so that AP will buffer the frames for us while we are not 353 * listening, then send probe requests to each channel and wait for 354 * the responses. After all channels are scanned, tune back to the 355 * original channel and send a nullfunc frame with power save bit 356 * off to trigger the AP to send us all the buffered frames. 357 * 358 * Note that while local->sw_scanning is true everything else but 359 * nullfunc frames and probe requests will be dropped in 360 * ieee80211_tx_h_check_assoc(). 361 */ 362 drv_sw_scan_start(local); 363 364 local->leave_oper_channel_time = jiffies; 365 local->next_scan_state = SCAN_DECISION; 366 local->scan_channel_idx = 0; 367 368 ieee80211_offchannel_stop_vifs(local); 369 370 /* ensure nullfunc is transmitted before leaving operating channel */ 371 ieee80211_flush_queues(local, NULL); 372 373 ieee80211_configure_filter(local); 374 375 /* We need to set power level at maximum rate for scanning. */ 376 ieee80211_hw_config(local, 0); 377 378 ieee80211_queue_delayed_work(&local->hw, 379 &local->scan_work, 0); 380 381 return 0; 382 } 383 384 static bool ieee80211_can_scan(struct ieee80211_local *local, 385 struct ieee80211_sub_if_data *sdata) 386 { 387 if (local->radar_detect_enabled) 388 return false; 389 390 if (!list_empty(&local->roc_list)) 391 return false; 392 393 if (sdata->vif.type == NL80211_IFTYPE_STATION && 394 sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL | 395 IEEE80211_STA_CONNECTION_POLL)) 396 return false; 397 398 return true; 399 } 400 401 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 402 { 403 lockdep_assert_held(&local->mtx); 404 405 if (!local->scan_req || local->scanning) 406 return; 407 408 if (!ieee80211_can_scan(local, 409 rcu_dereference_protected( 410 local->scan_sdata, 411 lockdep_is_held(&local->mtx)))) 412 return; 413 414 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 415 round_jiffies_relative(0)); 416 } 417 418 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 419 unsigned long *next_delay) 420 { 421 int i; 422 struct ieee80211_sub_if_data *sdata; 423 enum ieee80211_band band = local->hw.conf.chandef.chan->band; 424 u32 tx_flags; 425 426 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 427 if (local->scan_req->no_cck) 428 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 429 430 sdata = rcu_dereference_protected(local->scan_sdata, 431 lockdep_is_held(&local->mtx)); 432 433 for (i = 0; i < local->scan_req->n_ssids; i++) 434 ieee80211_send_probe_req( 435 sdata, NULL, 436 local->scan_req->ssids[i].ssid, 437 local->scan_req->ssids[i].ssid_len, 438 local->scan_req->ie, local->scan_req->ie_len, 439 local->scan_req->rates[band], false, 440 tx_flags, local->hw.conf.chandef.chan, true); 441 442 /* 443 * After sending probe requests, wait for probe responses 444 * on the channel. 445 */ 446 *next_delay = IEEE80211_CHANNEL_TIME; 447 local->next_scan_state = SCAN_DECISION; 448 } 449 450 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 451 struct cfg80211_scan_request *req) 452 { 453 struct ieee80211_local *local = sdata->local; 454 int rc; 455 456 lockdep_assert_held(&local->mtx); 457 458 if (local->scan_req) 459 return -EBUSY; 460 461 if (!ieee80211_can_scan(local, sdata)) { 462 /* wait for the work to finish/time out */ 463 local->scan_req = req; 464 rcu_assign_pointer(local->scan_sdata, sdata); 465 return 0; 466 } 467 468 if (local->ops->hw_scan) { 469 u8 *ies; 470 471 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN + 472 local->scan_ies_len + 473 req->ie_len; 474 local->hw_scan_req = kmalloc( 475 sizeof(*local->hw_scan_req) + 476 req->n_channels * sizeof(req->channels[0]) + 477 local->hw_scan_ies_bufsize, GFP_KERNEL); 478 if (!local->hw_scan_req) 479 return -ENOMEM; 480 481 local->hw_scan_req->ssids = req->ssids; 482 local->hw_scan_req->n_ssids = req->n_ssids; 483 ies = (u8 *)local->hw_scan_req + 484 sizeof(*local->hw_scan_req) + 485 req->n_channels * sizeof(req->channels[0]); 486 local->hw_scan_req->ie = ies; 487 local->hw_scan_req->flags = req->flags; 488 489 local->hw_scan_band = 0; 490 491 /* 492 * After allocating local->hw_scan_req, we must 493 * go through until ieee80211_prep_hw_scan(), so 494 * anything that might be changed here and leave 495 * this function early must not go after this 496 * allocation. 497 */ 498 } 499 500 local->scan_req = req; 501 rcu_assign_pointer(local->scan_sdata, sdata); 502 503 if (local->ops->hw_scan) { 504 __set_bit(SCAN_HW_SCANNING, &local->scanning); 505 } else if ((req->n_channels == 1) && 506 (req->channels[0] == local->_oper_chandef.chan)) { 507 /* 508 * If we are scanning only on the operating channel 509 * then we do not need to stop normal activities 510 */ 511 unsigned long next_delay; 512 513 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 514 515 ieee80211_recalc_idle(local); 516 517 /* Notify driver scan is starting, keep order of operations 518 * same as normal software scan, in case that matters. */ 519 drv_sw_scan_start(local); 520 521 ieee80211_configure_filter(local); /* accept probe-responses */ 522 523 /* We need to ensure power level is at max for scanning. */ 524 ieee80211_hw_config(local, 0); 525 526 if ((req->channels[0]->flags & 527 IEEE80211_CHAN_PASSIVE_SCAN) || 528 !local->scan_req->n_ssids) { 529 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 530 } else { 531 ieee80211_scan_state_send_probe(local, &next_delay); 532 next_delay = IEEE80211_CHANNEL_TIME; 533 } 534 535 /* Now, just wait a bit and we are all done! */ 536 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 537 next_delay); 538 return 0; 539 } else { 540 /* Do normal software scan */ 541 __set_bit(SCAN_SW_SCANNING, &local->scanning); 542 } 543 544 ieee80211_recalc_idle(local); 545 546 if (local->ops->hw_scan) { 547 WARN_ON(!ieee80211_prep_hw_scan(local)); 548 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 549 } else 550 rc = ieee80211_start_sw_scan(local); 551 552 if (rc) { 553 kfree(local->hw_scan_req); 554 local->hw_scan_req = NULL; 555 local->scanning = 0; 556 557 ieee80211_recalc_idle(local); 558 559 local->scan_req = NULL; 560 rcu_assign_pointer(local->scan_sdata, NULL); 561 } 562 563 return rc; 564 } 565 566 static unsigned long 567 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 568 { 569 /* 570 * TODO: channel switching also consumes quite some time, 571 * add that delay as well to get a better estimation 572 */ 573 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) 574 return IEEE80211_PASSIVE_CHANNEL_TIME; 575 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 576 } 577 578 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 579 unsigned long *next_delay) 580 { 581 bool associated = false; 582 bool tx_empty = true; 583 bool bad_latency; 584 struct ieee80211_sub_if_data *sdata; 585 struct ieee80211_channel *next_chan; 586 enum mac80211_scan_state next_scan_state; 587 588 /* 589 * check if at least one STA interface is associated, 590 * check if at least one STA interface has pending tx frames 591 * and grab the lowest used beacon interval 592 */ 593 mutex_lock(&local->iflist_mtx); 594 list_for_each_entry(sdata, &local->interfaces, list) { 595 if (!ieee80211_sdata_running(sdata)) 596 continue; 597 598 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 599 if (sdata->u.mgd.associated) { 600 associated = true; 601 602 if (!qdisc_all_tx_empty(sdata->dev)) { 603 tx_empty = false; 604 break; 605 } 606 } 607 } 608 } 609 mutex_unlock(&local->iflist_mtx); 610 611 next_chan = local->scan_req->channels[local->scan_channel_idx]; 612 613 /* 614 * we're currently scanning a different channel, let's 615 * see if we can scan another channel without interfering 616 * with the current traffic situation. 617 * 618 * Keep good latency, do not stay off-channel more than 125 ms. 619 */ 620 621 bad_latency = time_after(jiffies + 622 ieee80211_scan_get_channel_time(next_chan), 623 local->leave_oper_channel_time + HZ / 8); 624 625 if (associated && !tx_empty) { 626 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 627 next_scan_state = SCAN_ABORT; 628 else 629 next_scan_state = SCAN_SUSPEND; 630 } else if (associated && bad_latency) { 631 next_scan_state = SCAN_SUSPEND; 632 } else { 633 next_scan_state = SCAN_SET_CHANNEL; 634 } 635 636 local->next_scan_state = next_scan_state; 637 638 *next_delay = 0; 639 } 640 641 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 642 unsigned long *next_delay) 643 { 644 int skip; 645 struct ieee80211_channel *chan; 646 enum nl80211_bss_scan_width oper_scan_width; 647 648 skip = 0; 649 chan = local->scan_req->channels[local->scan_channel_idx]; 650 651 local->scan_chandef.chan = chan; 652 local->scan_chandef.center_freq1 = chan->center_freq; 653 local->scan_chandef.center_freq2 = 0; 654 switch (local->scan_req->scan_width) { 655 case NL80211_BSS_CHAN_WIDTH_5: 656 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 657 break; 658 case NL80211_BSS_CHAN_WIDTH_10: 659 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 660 break; 661 case NL80211_BSS_CHAN_WIDTH_20: 662 /* If scanning on oper channel, use whatever channel-type 663 * is currently in use. 664 */ 665 oper_scan_width = cfg80211_chandef_to_scan_width( 666 &local->_oper_chandef); 667 if (chan == local->_oper_chandef.chan && 668 oper_scan_width == local->scan_req->scan_width) 669 local->scan_chandef = local->_oper_chandef; 670 else 671 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 672 break; 673 } 674 675 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 676 skip = 1; 677 678 /* advance state machine to next channel/band */ 679 local->scan_channel_idx++; 680 681 if (skip) { 682 /* if we skip this channel return to the decision state */ 683 local->next_scan_state = SCAN_DECISION; 684 return; 685 } 686 687 /* 688 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 689 * (which unfortunately doesn't say _why_ step a) is done, 690 * but it waits for the probe delay or until a frame is 691 * received - and the received frame would update the NAV). 692 * For now, we do not support waiting until a frame is 693 * received. 694 * 695 * In any case, it is not necessary for a passive scan. 696 */ 697 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN || 698 !local->scan_req->n_ssids) { 699 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 700 local->next_scan_state = SCAN_DECISION; 701 return; 702 } 703 704 /* active scan, send probes */ 705 *next_delay = IEEE80211_PROBE_DELAY; 706 local->next_scan_state = SCAN_SEND_PROBE; 707 } 708 709 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 710 unsigned long *next_delay) 711 { 712 /* switch back to the operating channel */ 713 local->scan_chandef.chan = NULL; 714 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 715 716 /* disable PS */ 717 ieee80211_offchannel_return(local); 718 719 *next_delay = HZ / 5; 720 /* afterwards, resume scan & go to next channel */ 721 local->next_scan_state = SCAN_RESUME; 722 } 723 724 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 725 unsigned long *next_delay) 726 { 727 ieee80211_offchannel_stop_vifs(local); 728 729 if (local->ops->flush) { 730 ieee80211_flush_queues(local, NULL); 731 *next_delay = 0; 732 } else 733 *next_delay = HZ / 10; 734 735 /* remember when we left the operating channel */ 736 local->leave_oper_channel_time = jiffies; 737 738 /* advance to the next channel to be scanned */ 739 local->next_scan_state = SCAN_SET_CHANNEL; 740 } 741 742 void ieee80211_scan_work(struct work_struct *work) 743 { 744 struct ieee80211_local *local = 745 container_of(work, struct ieee80211_local, scan_work.work); 746 struct ieee80211_sub_if_data *sdata; 747 unsigned long next_delay = 0; 748 bool aborted, hw_scan; 749 750 mutex_lock(&local->mtx); 751 752 sdata = rcu_dereference_protected(local->scan_sdata, 753 lockdep_is_held(&local->mtx)); 754 755 /* When scanning on-channel, the first-callback means completed. */ 756 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 757 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 758 goto out_complete; 759 } 760 761 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 762 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 763 goto out_complete; 764 } 765 766 if (!sdata || !local->scan_req) 767 goto out; 768 769 if (local->scan_req && !local->scanning) { 770 struct cfg80211_scan_request *req = local->scan_req; 771 int rc; 772 773 local->scan_req = NULL; 774 rcu_assign_pointer(local->scan_sdata, NULL); 775 776 rc = __ieee80211_start_scan(sdata, req); 777 if (rc) { 778 /* need to complete scan in cfg80211 */ 779 local->scan_req = req; 780 aborted = true; 781 goto out_complete; 782 } else 783 goto out; 784 } 785 786 /* 787 * Avoid re-scheduling when the sdata is going away. 788 */ 789 if (!ieee80211_sdata_running(sdata)) { 790 aborted = true; 791 goto out_complete; 792 } 793 794 /* 795 * as long as no delay is required advance immediately 796 * without scheduling a new work 797 */ 798 do { 799 if (!ieee80211_sdata_running(sdata)) { 800 aborted = true; 801 goto out_complete; 802 } 803 804 switch (local->next_scan_state) { 805 case SCAN_DECISION: 806 /* if no more bands/channels left, complete scan */ 807 if (local->scan_channel_idx >= local->scan_req->n_channels) { 808 aborted = false; 809 goto out_complete; 810 } 811 ieee80211_scan_state_decision(local, &next_delay); 812 break; 813 case SCAN_SET_CHANNEL: 814 ieee80211_scan_state_set_channel(local, &next_delay); 815 break; 816 case SCAN_SEND_PROBE: 817 ieee80211_scan_state_send_probe(local, &next_delay); 818 break; 819 case SCAN_SUSPEND: 820 ieee80211_scan_state_suspend(local, &next_delay); 821 break; 822 case SCAN_RESUME: 823 ieee80211_scan_state_resume(local, &next_delay); 824 break; 825 case SCAN_ABORT: 826 aborted = true; 827 goto out_complete; 828 } 829 } while (next_delay == 0); 830 831 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 832 goto out; 833 834 out_complete: 835 hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); 836 __ieee80211_scan_completed(&local->hw, aborted, hw_scan); 837 out: 838 mutex_unlock(&local->mtx); 839 } 840 841 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 842 struct cfg80211_scan_request *req) 843 { 844 int res; 845 846 mutex_lock(&sdata->local->mtx); 847 res = __ieee80211_start_scan(sdata, req); 848 mutex_unlock(&sdata->local->mtx); 849 850 return res; 851 } 852 853 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 854 const u8 *ssid, u8 ssid_len, 855 struct ieee80211_channel *chan, 856 enum nl80211_bss_scan_width scan_width) 857 { 858 struct ieee80211_local *local = sdata->local; 859 int ret = -EBUSY; 860 enum ieee80211_band band; 861 862 mutex_lock(&local->mtx); 863 864 /* busy scanning */ 865 if (local->scan_req) 866 goto unlock; 867 868 /* fill internal scan request */ 869 if (!chan) { 870 int i, max_n; 871 int n_ch = 0; 872 873 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 874 if (!local->hw.wiphy->bands[band]) 875 continue; 876 877 max_n = local->hw.wiphy->bands[band]->n_channels; 878 for (i = 0; i < max_n; i++) { 879 struct ieee80211_channel *tmp_ch = 880 &local->hw.wiphy->bands[band]->channels[i]; 881 882 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS | 883 IEEE80211_CHAN_DISABLED)) 884 continue; 885 886 local->int_scan_req->channels[n_ch] = tmp_ch; 887 n_ch++; 888 } 889 } 890 891 if (WARN_ON_ONCE(n_ch == 0)) 892 goto unlock; 893 894 local->int_scan_req->n_channels = n_ch; 895 } else { 896 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS | 897 IEEE80211_CHAN_DISABLED))) 898 goto unlock; 899 900 local->int_scan_req->channels[0] = chan; 901 local->int_scan_req->n_channels = 1; 902 } 903 904 local->int_scan_req->ssids = &local->scan_ssid; 905 local->int_scan_req->n_ssids = 1; 906 local->int_scan_req->scan_width = scan_width; 907 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 908 local->int_scan_req->ssids[0].ssid_len = ssid_len; 909 910 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 911 unlock: 912 mutex_unlock(&local->mtx); 913 return ret; 914 } 915 916 /* 917 * Only call this function when a scan can't be queued -- under RTNL. 918 */ 919 void ieee80211_scan_cancel(struct ieee80211_local *local) 920 { 921 /* 922 * We are canceling software scan, or deferred scan that was not 923 * yet really started (see __ieee80211_start_scan ). 924 * 925 * Regarding hardware scan: 926 * - we can not call __ieee80211_scan_completed() as when 927 * SCAN_HW_SCANNING bit is set this function change 928 * local->hw_scan_req to operate on 5G band, what race with 929 * driver which can use local->hw_scan_req 930 * 931 * - we can not cancel scan_work since driver can schedule it 932 * by ieee80211_scan_completed(..., true) to finish scan 933 * 934 * Hence we only call the cancel_hw_scan() callback, but the low-level 935 * driver is still responsible for calling ieee80211_scan_completed() 936 * after the scan was completed/aborted. 937 */ 938 939 mutex_lock(&local->mtx); 940 if (!local->scan_req) 941 goto out; 942 943 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 944 if (local->ops->cancel_hw_scan) 945 drv_cancel_hw_scan(local, 946 rcu_dereference_protected(local->scan_sdata, 947 lockdep_is_held(&local->mtx))); 948 goto out; 949 } 950 951 /* 952 * If the work is currently running, it must be blocked on 953 * the mutex, but we'll set scan_sdata = NULL and it'll 954 * simply exit once it acquires the mutex. 955 */ 956 cancel_delayed_work(&local->scan_work); 957 /* and clean up */ 958 __ieee80211_scan_completed(&local->hw, true, false); 959 out: 960 mutex_unlock(&local->mtx); 961 } 962 963 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 964 struct cfg80211_sched_scan_request *req) 965 { 966 struct ieee80211_local *local = sdata->local; 967 struct ieee80211_sched_scan_ies sched_scan_ies = {}; 968 struct cfg80211_chan_def chandef; 969 int ret, i, iebufsz; 970 971 iebufsz = 2 + IEEE80211_MAX_SSID_LEN + 972 local->scan_ies_len + req->ie_len; 973 974 mutex_lock(&local->mtx); 975 976 if (rcu_access_pointer(local->sched_scan_sdata)) { 977 ret = -EBUSY; 978 goto out; 979 } 980 981 if (!local->ops->sched_scan_start) { 982 ret = -ENOTSUPP; 983 goto out; 984 } 985 986 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 987 if (!local->hw.wiphy->bands[i]) 988 continue; 989 990 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL); 991 if (!sched_scan_ies.ie[i]) { 992 ret = -ENOMEM; 993 goto out_free; 994 } 995 996 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 997 998 sched_scan_ies.len[i] = 999 ieee80211_build_preq_ies(local, sched_scan_ies.ie[i], 1000 iebufsz, req->ie, req->ie_len, 1001 i, (u32) -1, &chandef); 1002 } 1003 1004 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1005 if (ret == 0) 1006 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1007 1008 out_free: 1009 while (i > 0) 1010 kfree(sched_scan_ies.ie[--i]); 1011 out: 1012 mutex_unlock(&local->mtx); 1013 return ret; 1014 } 1015 1016 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 1017 { 1018 struct ieee80211_local *local = sdata->local; 1019 int ret = 0; 1020 1021 mutex_lock(&local->mtx); 1022 1023 if (!local->ops->sched_scan_stop) { 1024 ret = -ENOTSUPP; 1025 goto out; 1026 } 1027 1028 if (rcu_access_pointer(local->sched_scan_sdata)) 1029 drv_sched_scan_stop(local, sdata); 1030 1031 out: 1032 mutex_unlock(&local->mtx); 1033 1034 return ret; 1035 } 1036 1037 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1038 { 1039 struct ieee80211_local *local = hw_to_local(hw); 1040 1041 trace_api_sched_scan_results(local); 1042 1043 cfg80211_sched_scan_results(hw->wiphy); 1044 } 1045 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1046 1047 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1048 { 1049 struct ieee80211_local *local = 1050 container_of(work, struct ieee80211_local, 1051 sched_scan_stopped_work); 1052 1053 mutex_lock(&local->mtx); 1054 1055 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1056 mutex_unlock(&local->mtx); 1057 return; 1058 } 1059 1060 rcu_assign_pointer(local->sched_scan_sdata, NULL); 1061 1062 mutex_unlock(&local->mtx); 1063 1064 cfg80211_sched_scan_stopped(local->hw.wiphy); 1065 } 1066 1067 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1068 { 1069 struct ieee80211_local *local = hw_to_local(hw); 1070 1071 trace_api_sched_scan_stopped(local); 1072 1073 ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work); 1074 } 1075 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1076