Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/net80211/ieee80211_scan_sw.c
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1 /*- 2 * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 29 /* 30 * IEEE 802.11 scanning support. 31 */ 32 #include "opt_wlan.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/proc.h> 37 #include <sys/kernel.h> 38 #include <sys/malloc.h> 39 #include <sys/condvar.h> 40 41 #include <sys/socket.h> 42 43 #include <net/if.h> 44 #include <net/if_var.h> 45 #include <net/if_media.h> 46 #include <net/ethernet.h> 47 48 #include <net80211/ieee80211_var.h> 49 50 #include <net80211/ieee80211_scan_sw.h> 51 52 #include <net/bpf.h> 53 54 struct scan_state { 55 struct ieee80211_scan_state base; /* public state */ 56 57 u_int ss_iflags; /* flags used internally */ 58 #define ISCAN_MINDWELL 0x0001 /* min dwell time reached */ 59 #define ISCAN_DISCARD 0x0002 /* discard rx'd frames */ 60 #define ISCAN_INTERRUPT 0x0004 /* interrupt current scan */ 61 #define ISCAN_CANCEL 0x0008 /* cancel current scan */ 62 #define ISCAN_PAUSE (ISCAN_INTERRUPT | ISCAN_CANCEL) 63 #define ISCAN_ABORT 0x0010 /* end the scan immediately */ 64 #define ISCAN_RUNNING 0x0020 /* scan was started */ 65 66 unsigned long ss_chanmindwell; /* min dwell on curchan */ 67 unsigned long ss_scanend; /* time scan must stop */ 68 u_int ss_duration; /* duration for next scan */ 69 struct task ss_scan_start; /* scan start */ 70 struct timeout_task ss_scan_curchan; /* scan execution */ 71 }; 72 #define SCAN_PRIVATE(ss) ((struct scan_state *) ss) 73 74 /* 75 * Amount of time to go off-channel during a background 76 * scan. This value should be large enough to catch most 77 * ap's but short enough that we can return on-channel 78 * before our listen interval expires. 79 * 80 * XXX tunable 81 * XXX check against configured listen interval 82 */ 83 #define IEEE80211_SCAN_OFFCHANNEL msecs_to_ticks(150) 84 85 static void scan_curchan(struct ieee80211_scan_state *, unsigned long); 86 static void scan_mindwell(struct ieee80211_scan_state *); 87 static void scan_signal(struct ieee80211_scan_state *, int); 88 static void scan_signal_locked(struct ieee80211_scan_state *, int); 89 static void scan_start(void *, int); 90 static void scan_curchan_task(void *, int); 91 static void scan_end(struct ieee80211_scan_state *, int); 92 static void scan_done(struct ieee80211_scan_state *, int); 93 94 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state"); 95 96 static void 97 ieee80211_swscan_detach(struct ieee80211com *ic) 98 { 99 struct ieee80211_scan_state *ss = ic->ic_scan; 100 101 if (ss != NULL) { 102 scan_signal(ss, ISCAN_ABORT); 103 ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_start); 104 taskqueue_drain_timeout(ic->ic_tq, 105 &SCAN_PRIVATE(ss)->ss_scan_curchan); 106 KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0, 107 ("scan still running")); 108 109 /* 110 * For now, do the ss_ops detach here rather 111 * than ieee80211_scan_detach(). 112 * 113 * I'll figure out how to cleanly split things up 114 * at a later date. 115 */ 116 if (ss->ss_ops != NULL) { 117 ss->ss_ops->scan_detach(ss); 118 ss->ss_ops = NULL; 119 } 120 ic->ic_scan = NULL; 121 IEEE80211_FREE(SCAN_PRIVATE(ss), M_80211_SCAN); 122 } 123 } 124 125 static void 126 ieee80211_swscan_vattach(struct ieee80211vap *vap) 127 { 128 /* nothing to do for now */ 129 /* 130 * TODO: all of the vap scan calls should be methods! 131 */ 132 133 } 134 135 static void 136 ieee80211_swscan_vdetach(struct ieee80211vap *vap) 137 { 138 struct ieee80211com *ic = vap->iv_ic; 139 struct ieee80211_scan_state *ss = ic->ic_scan; 140 141 IEEE80211_LOCK_ASSERT(ic); 142 143 if (ss != NULL && ss->ss_vap == vap && 144 (ic->ic_flags & IEEE80211_F_SCAN)) 145 scan_signal_locked(ss, ISCAN_ABORT); 146 } 147 148 static void 149 ieee80211_swscan_set_scan_duration(struct ieee80211vap *vap, u_int duration) 150 { 151 struct ieee80211com *ic = vap->iv_ic; 152 struct ieee80211_scan_state *ss = ic->ic_scan; 153 154 IEEE80211_LOCK_ASSERT(ic); 155 156 /* NB: flush frames rx'd before 1st channel change */ 157 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD; 158 SCAN_PRIVATE(ss)->ss_duration = duration; 159 } 160 161 /* 162 * Start a scan unless one is already going. 163 */ 164 static int 165 ieee80211_swscan_start_scan_locked(const struct ieee80211_scanner *scan, 166 struct ieee80211vap *vap, int flags, u_int duration, 167 u_int mindwell, u_int maxdwell, 168 u_int nssid, const struct ieee80211_scan_ssid ssids[]) 169 { 170 struct ieee80211com *ic = vap->iv_ic; 171 struct ieee80211_scan_state *ss = ic->ic_scan; 172 173 IEEE80211_LOCK_ASSERT(ic); 174 175 if (ic->ic_flags & IEEE80211_F_CSAPENDING) { 176 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 177 "%s: scan inhibited by pending channel change\n", __func__); 178 } else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) { 179 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 180 "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n" 181 , __func__ 182 , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive" 183 , duration, mindwell, maxdwell 184 , ieee80211_phymode_name[vap->iv_des_mode] 185 , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append" 186 , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : "" 187 , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : "" 188 , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : "" 189 , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : "" 190 , flags & IEEE80211_SCAN_ONCE ? ", once" : "" 191 ); 192 193 ieee80211_scan_update_locked(vap, scan); 194 if (ss->ss_ops != NULL) { 195 if ((flags & IEEE80211_SCAN_NOSSID) == 0) 196 ieee80211_scan_copy_ssid(vap, ss, nssid, ssids); 197 198 /* NB: top 4 bits for internal use */ 199 ss->ss_flags = flags & 0xfff; 200 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) 201 vap->iv_stats.is_scan_active++; 202 else 203 vap->iv_stats.is_scan_passive++; 204 if (flags & IEEE80211_SCAN_FLUSH) 205 ss->ss_ops->scan_flush(ss); 206 if (flags & IEEE80211_SCAN_BGSCAN) 207 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN; 208 209 /* Set duration for this particular scan */ 210 ieee80211_swscan_set_scan_duration(vap, duration); 211 212 ss->ss_next = 0; 213 ss->ss_mindwell = mindwell; 214 ss->ss_maxdwell = maxdwell; 215 /* NB: scan_start must be before the scan runtask */ 216 ss->ss_ops->scan_start(ss, vap); 217 #ifdef IEEE80211_DEBUG 218 if (ieee80211_msg_scan(vap)) 219 ieee80211_scan_dump(ss); 220 #endif /* IEEE80211_DEBUG */ 221 ic->ic_flags |= IEEE80211_F_SCAN; 222 223 /* Start scan task */ 224 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_start); 225 } 226 return 1; 227 } else { 228 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 229 "%s: %s scan already in progress\n", __func__, 230 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"); 231 } 232 return 0; 233 } 234 235 236 /* 237 * Start a scan unless one is already going. 238 * 239 * Called without the comlock held; grab the comlock as appropriate. 240 */ 241 static int 242 ieee80211_swscan_start_scan(const struct ieee80211_scanner *scan, 243 struct ieee80211vap *vap, int flags, 244 u_int duration, u_int mindwell, u_int maxdwell, 245 u_int nssid, const struct ieee80211_scan_ssid ssids[]) 246 { 247 struct ieee80211com *ic = vap->iv_ic; 248 int result; 249 250 IEEE80211_UNLOCK_ASSERT(ic); 251 252 IEEE80211_LOCK(ic); 253 result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration, 254 mindwell, maxdwell, nssid, ssids); 255 IEEE80211_UNLOCK(ic); 256 257 return result; 258 } 259 260 /* 261 * Check the scan cache for an ap/channel to use; if that 262 * fails then kick off a new scan. 263 * 264 * Called with the comlock held. 265 * 266 * XXX TODO: split out! 267 */ 268 static int 269 ieee80211_swscan_check_scan(const struct ieee80211_scanner *scan, 270 struct ieee80211vap *vap, int flags, 271 u_int duration, u_int mindwell, u_int maxdwell, 272 u_int nssid, const struct ieee80211_scan_ssid ssids[]) 273 { 274 struct ieee80211com *ic = vap->iv_ic; 275 struct ieee80211_scan_state *ss = ic->ic_scan; 276 int result; 277 278 IEEE80211_LOCK_ASSERT(ic); 279 280 if (ss->ss_ops != NULL) { 281 /* XXX verify ss_ops matches vap->iv_opmode */ 282 if ((flags & IEEE80211_SCAN_NOSSID) == 0) { 283 /* 284 * Update the ssid list and mark flags so if 285 * we call start_scan it doesn't duplicate work. 286 */ 287 ieee80211_scan_copy_ssid(vap, ss, nssid, ssids); 288 flags |= IEEE80211_SCAN_NOSSID; 289 } 290 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 && 291 (flags & IEEE80211_SCAN_FLUSH) == 0 && 292 ieee80211_time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) { 293 /* 294 * We're not currently scanning and the cache is 295 * deemed hot enough to consult. Lock out others 296 * by marking IEEE80211_F_SCAN while we decide if 297 * something is already in the scan cache we can 298 * use. Also discard any frames that might come 299 * in while temporarily marked as scanning. 300 */ 301 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 302 "cache hot; ic_lastscan=%d, scanvalid=%d, ticks=%d\n", 303 ic->ic_lastscan, 304 vap->iv_scanvalid, 305 ticks); 306 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD; 307 ic->ic_flags |= IEEE80211_F_SCAN; 308 309 /* NB: need to use supplied flags in check */ 310 ss->ss_flags = flags & 0xff; 311 result = ss->ss_ops->scan_end(ss, vap); 312 313 ic->ic_flags &= ~IEEE80211_F_SCAN; 314 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD; 315 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 316 "%s: scan_end returned %d\n", __func__, result); 317 if (result) { 318 ieee80211_notify_scan_done(vap); 319 return 1; 320 } 321 } 322 } 323 result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration, 324 mindwell, maxdwell, nssid, ssids); 325 326 return result; 327 } 328 329 /* 330 * Restart a previous scan. If the previous scan completed 331 * then we start again using the existing channel list. 332 */ 333 static int 334 ieee80211_swscan_bg_scan(const struct ieee80211_scanner *scan, 335 struct ieee80211vap *vap, int flags) 336 { 337 struct ieee80211com *ic = vap->iv_ic; 338 struct ieee80211_scan_state *ss = ic->ic_scan; 339 340 /* XXX assert unlocked? */ 341 // IEEE80211_UNLOCK_ASSERT(ic); 342 343 IEEE80211_LOCK(ic); 344 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) { 345 u_int duration; 346 /* 347 * Go off-channel for a fixed interval that is large 348 * enough to catch most ap's but short enough that 349 * we can return on-channel before our listen interval 350 * expires. 351 */ 352 duration = IEEE80211_SCAN_OFFCHANNEL; 353 354 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 355 "%s: %s scan, ticks %u duration %u\n", __func__, 356 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive", 357 ticks, duration); 358 359 ieee80211_scan_update_locked(vap, scan); 360 if (ss->ss_ops != NULL) { 361 ss->ss_vap = vap; 362 /* 363 * A background scan does not select a new sta; it 364 * just refreshes the scan cache. Also, indicate 365 * the scan logic should follow the beacon schedule: 366 * we go off-channel and scan for a while, then 367 * return to the bss channel to receive a beacon, 368 * then go off-channel again. All during this time 369 * we notify the ap we're in power save mode. When 370 * the scan is complete we leave power save mode. 371 * If any beacon indicates there are frames pending 372 * for us then we drop out of power save mode 373 * (and background scan) automatically by way of the 374 * usual sta power save logic. 375 */ 376 ss->ss_flags |= IEEE80211_SCAN_NOPICK 377 | IEEE80211_SCAN_BGSCAN 378 | flags 379 ; 380 /* if previous scan completed, restart */ 381 if (ss->ss_next >= ss->ss_last) { 382 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) 383 vap->iv_stats.is_scan_active++; 384 else 385 vap->iv_stats.is_scan_passive++; 386 /* 387 * NB: beware of the scan cache being flushed; 388 * if the channel list is empty use the 389 * scan_start method to populate it. 390 */ 391 ss->ss_next = 0; 392 if (ss->ss_last != 0) 393 ss->ss_ops->scan_restart(ss, vap); 394 else { 395 ss->ss_ops->scan_start(ss, vap); 396 #ifdef IEEE80211_DEBUG 397 if (ieee80211_msg_scan(vap)) 398 ieee80211_scan_dump(ss); 399 #endif /* IEEE80211_DEBUG */ 400 } 401 } 402 ieee80211_swscan_set_scan_duration(vap, duration); 403 ss->ss_maxdwell = duration; 404 ic->ic_flags |= IEEE80211_F_SCAN; 405 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN; 406 ieee80211_runtask(ic, 407 &SCAN_PRIVATE(ss)->ss_scan_start); 408 } else { 409 /* XXX msg+stat */ 410 } 411 } else { 412 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 413 "%s: %s scan already in progress\n", __func__, 414 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"); 415 } 416 IEEE80211_UNLOCK(ic); 417 418 /* NB: racey, does it matter? */ 419 return (ic->ic_flags & IEEE80211_F_SCAN); 420 } 421 422 /* 423 * Taskqueue work to cancel a scan. 424 * 425 * Note: for offload scan devices, we may want to call into the 426 * driver to try and cancel scanning, however it may not be cancelable. 427 */ 428 static void 429 cancel_scan(struct ieee80211vap *vap, int any, const char *func) 430 { 431 struct ieee80211com *ic = vap->iv_ic; 432 struct ieee80211_scan_state *ss = ic->ic_scan; 433 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 434 int signal; 435 436 IEEE80211_LOCK(ic); 437 signal = any ? ISCAN_PAUSE : ISCAN_CANCEL; 438 if ((ic->ic_flags & IEEE80211_F_SCAN) && 439 (any || ss->ss_vap == vap) && 440 (ss_priv->ss_iflags & signal) == 0) { 441 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 442 "%s: %s %s scan\n", func, 443 any ? "pause" : "cancel", 444 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? 445 "active" : "passive"); 446 447 /* clear bg scan NOPICK */ 448 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK; 449 /* mark request and wake up the scan task */ 450 scan_signal_locked(ss, signal); 451 } else { 452 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 453 "%s: called; F_SCAN=%d, vap=%s, signal=%d\n", 454 func, 455 !! (ic->ic_flags & IEEE80211_F_SCAN), 456 (ss->ss_vap == vap ? "match" : "nomatch"), 457 !! (ss_priv->ss_iflags & signal)); 458 } 459 IEEE80211_UNLOCK(ic); 460 } 461 462 /* 463 * Cancel any scan currently going on for the specified vap. 464 */ 465 static void 466 ieee80211_swscan_cancel_scan(struct ieee80211vap *vap) 467 { 468 cancel_scan(vap, 0, __func__); 469 } 470 471 /* 472 * Cancel any scan currently going on. 473 */ 474 static void 475 ieee80211_swscan_cancel_anyscan(struct ieee80211vap *vap) 476 { 477 478 /* XXX for now - just don't do this per packet. */ 479 if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) 480 return; 481 482 cancel_scan(vap, 1, __func__); 483 } 484 485 /* 486 * Manually switch to the next channel in the channel list. 487 * Provided for drivers that manage scanning themselves 488 * (e.g. for firmware-based devices). 489 */ 490 static void 491 ieee80211_swscan_scan_next(struct ieee80211vap *vap) 492 { 493 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan; 494 495 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__); 496 497 /* wake up the scan task */ 498 scan_signal(ss, 0); 499 } 500 501 /* 502 * Manually stop a scan that is currently running. 503 * Provided for drivers that are not able to scan single channels 504 * (e.g. for firmware-based devices). 505 */ 506 static void 507 ieee80211_swscan_scan_done(struct ieee80211vap *vap) 508 { 509 struct ieee80211com *ic = vap->iv_ic; 510 struct ieee80211_scan_state *ss = ic->ic_scan; 511 512 IEEE80211_LOCK_ASSERT(ic); 513 514 scan_signal_locked(ss, 0); 515 } 516 517 /* 518 * Probe the current channel, if allowed, while scanning. 519 * If the channel is not marked passive-only then send 520 * a probe request immediately. Otherwise mark state and 521 * listen for beacons on the channel; if we receive something 522 * then we'll transmit a probe request. 523 */ 524 static void 525 ieee80211_swscan_probe_curchan(struct ieee80211vap *vap, int force) 526 { 527 struct ieee80211com *ic = vap->iv_ic; 528 struct ieee80211_scan_state *ss = ic->ic_scan; 529 struct ifnet *ifp = vap->iv_ifp; 530 int i; 531 532 /* 533 * Full-offload scan devices don't require this. 534 */ 535 if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) 536 return; 537 538 /* 539 * Send directed probe requests followed by any 540 * broadcast probe request. 541 * XXX remove dependence on ic/vap->iv_bss 542 */ 543 for (i = 0; i < ss->ss_nssid; i++) 544 ieee80211_send_probereq(vap->iv_bss, 545 vap->iv_myaddr, ifp->if_broadcastaddr, 546 ifp->if_broadcastaddr, 547 ss->ss_ssid[i].ssid, ss->ss_ssid[i].len); 548 if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0) 549 ieee80211_send_probereq(vap->iv_bss, 550 vap->iv_myaddr, ifp->if_broadcastaddr, 551 ifp->if_broadcastaddr, 552 "", 0); 553 } 554 555 /* 556 * Scan curchan. If this is an active scan and the channel 557 * is not marked passive then send probe request frame(s). 558 * Arrange for the channel change after maxdwell ticks. 559 */ 560 static void 561 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell) 562 { 563 struct ieee80211vap *vap = ss->ss_vap; 564 struct ieee80211com *ic = ss->ss_ic; 565 566 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 567 "%s: calling; maxdwell=%lu\n", 568 __func__, 569 maxdwell); 570 IEEE80211_LOCK(ic); 571 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) 572 ieee80211_probe_curchan(vap, 0); 573 taskqueue_enqueue_timeout(ic->ic_tq, 574 &SCAN_PRIVATE(ss)->ss_scan_curchan, maxdwell); 575 IEEE80211_UNLOCK(ic); 576 } 577 578 static void 579 scan_signal(struct ieee80211_scan_state *ss, int iflags) 580 { 581 struct ieee80211com *ic = ss->ss_ic; 582 583 IEEE80211_UNLOCK_ASSERT(ic); 584 585 IEEE80211_LOCK(ic); 586 scan_signal_locked(ss, iflags); 587 IEEE80211_UNLOCK(ic); 588 } 589 590 static void 591 scan_signal_locked(struct ieee80211_scan_state *ss, int iflags) 592 { 593 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 594 struct timeout_task *scan_task = &ss_priv->ss_scan_curchan; 595 struct ieee80211com *ic = ss->ss_ic; 596 597 IEEE80211_LOCK_ASSERT(ic); 598 599 ss_priv->ss_iflags |= iflags; 600 if (ss_priv->ss_iflags & ISCAN_RUNNING) { 601 if (taskqueue_cancel_timeout(ic->ic_tq, scan_task, NULL) == 0) 602 taskqueue_enqueue_timeout(ic->ic_tq, scan_task, 0); 603 } 604 } 605 606 /* 607 * Handle mindwell requirements completed; initiate a channel 608 * change to the next channel asap. 609 */ 610 static void 611 scan_mindwell(struct ieee80211_scan_state *ss) 612 { 613 614 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: called\n", 615 __func__); 616 617 scan_signal(ss, 0); 618 } 619 620 static void 621 scan_start(void *arg, int pending) 622 { 623 #define ISCAN_REP (ISCAN_MINDWELL | ISCAN_DISCARD) 624 struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg; 625 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 626 struct ieee80211vap *vap = ss->ss_vap; 627 struct ieee80211com *ic = ss->ss_ic; 628 629 IEEE80211_LOCK(ic); 630 if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 || 631 (ss_priv->ss_iflags & ISCAN_ABORT)) { 632 /* Cancelled before we started */ 633 scan_done(ss, 0); 634 return; 635 } 636 637 if (ss->ss_next == ss->ss_last) { 638 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 639 "%s: no channels to scan\n", __func__); 640 scan_done(ss, 1); 641 return; 642 } 643 644 /* 645 * Put the station into power save mode. 646 * 647 * This is only required if we're not a full-offload devices; 648 * those devices manage scan/traffic differently. 649 */ 650 if (((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0) && 651 vap->iv_opmode == IEEE80211_M_STA && 652 vap->iv_state == IEEE80211_S_RUN) { 653 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) { 654 /* Enable station power save mode */ 655 vap->iv_sta_ps(vap, 1); 656 /* Wait until null data frame will be ACK'ed */ 657 mtx_sleep(vap, IEEE80211_LOCK_OBJ(ic), PCATCH, 658 "sta_ps", msecs_to_ticks(10)); 659 if (ss_priv->ss_iflags & ISCAN_ABORT) { 660 scan_done(ss, 0); 661 return; 662 } 663 } 664 } 665 666 ss_priv->ss_scanend = ticks + ss_priv->ss_duration; 667 668 /* XXX scan state can change! Re-validate scan state! */ 669 670 IEEE80211_UNLOCK(ic); 671 672 ic->ic_scan_start(ic); /* notify driver */ 673 674 scan_curchan_task(ss, 0); 675 } 676 677 static void 678 scan_curchan_task(void *arg, int pending) 679 { 680 struct ieee80211_scan_state *ss = arg; 681 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 682 struct ieee80211com *ic = ss->ss_ic; 683 struct ieee80211_channel *chan; 684 unsigned long maxdwell; 685 int scandone, scanstop; 686 687 IEEE80211_LOCK(ic); 688 end: 689 /* 690 * Note: only /end/ the scan if we're CANCEL rather than 691 * CANCEL+INTERRUPT (ie, 'PAUSE'). 692 * 693 * We can stop the scan if we hit cancel, but we shouldn't 694 * call scan_end(ss, 1) if we're just PAUSEing the scan. 695 */ 696 scandone = (ss->ss_next >= ss->ss_last) || 697 ((ss_priv->ss_iflags & ISCAN_PAUSE) == ISCAN_CANCEL); 698 scanstop = (ss->ss_next >= ss->ss_last) || 699 ((ss_priv->ss_iflags & ISCAN_CANCEL) != 0); 700 701 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, 702 "%s: loop start; scandone=%d, scanstop=%d, ss_iflags=0x%x, ss_next=%u, ss_last=%u\n", 703 __func__, 704 scandone, 705 scanstop, 706 (uint32_t) ss_priv->ss_iflags, 707 (uint32_t) ss->ss_next, 708 (uint32_t) ss->ss_last); 709 710 if (scanstop || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) || 711 (ss_priv->ss_iflags & ISCAN_ABORT) || 712 ieee80211_time_after(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) { 713 ss_priv->ss_iflags &= ~ISCAN_RUNNING; 714 scan_end(ss, scandone); 715 return; 716 } else 717 ss_priv->ss_iflags |= ISCAN_RUNNING; 718 719 chan = ss->ss_chans[ss->ss_next++]; 720 721 /* 722 * Watch for truncation due to the scan end time. 723 */ 724 if (ieee80211_time_after(ticks + ss->ss_maxdwell, ss_priv->ss_scanend)) 725 maxdwell = ss_priv->ss_scanend - ticks; 726 else 727 maxdwell = ss->ss_maxdwell; 728 729 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, 730 "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n", 731 __func__, 732 ieee80211_chan2ieee(ic, ic->ic_curchan), 733 ieee80211_channel_type_char(ic->ic_curchan), 734 ieee80211_chan2ieee(ic, chan), 735 ieee80211_channel_type_char(chan), 736 (ss->ss_flags & IEEE80211_SCAN_ACTIVE) && 737 (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ? 738 "active" : "passive", 739 ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell)); 740 741 /* 742 * Potentially change channel and phy mode. 743 */ 744 ic->ic_curchan = chan; 745 ic->ic_rt = ieee80211_get_ratetable(chan); 746 IEEE80211_UNLOCK(ic); 747 /* 748 * Perform the channel change and scan unlocked so the driver 749 * may sleep. Once set_channel returns the hardware has 750 * completed the channel change. 751 */ 752 ic->ic_set_channel(ic); 753 ieee80211_radiotap_chan_change(ic); 754 755 /* 756 * Scan curchan. Drivers for "intelligent hardware" 757 * override ic_scan_curchan to tell the device to do 758 * the work. Otherwise we manage the work ourselves; 759 * sending a probe request (as needed), and arming the 760 * timeout to switch channels after maxdwell ticks. 761 * 762 * scan_curchan should only pause for the time required to 763 * prepare/initiate the hardware for the scan (if at all). 764 */ 765 ic->ic_scan_curchan(ss, maxdwell); 766 IEEE80211_LOCK(ic); 767 768 /* XXX scan state can change! Re-validate scan state! */ 769 770 ss_priv->ss_chanmindwell = ticks + ss->ss_mindwell; 771 /* clear mindwell lock and initial channel change flush */ 772 ss_priv->ss_iflags &= ~ISCAN_REP; 773 774 if (ss_priv->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)) { 775 taskqueue_cancel_timeout(ic->ic_tq, &ss_priv->ss_scan_curchan, 776 NULL); 777 goto end; 778 } 779 780 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: waiting\n", 781 __func__); 782 IEEE80211_UNLOCK(ic); 783 } 784 785 static void 786 scan_end(struct ieee80211_scan_state *ss, int scandone) 787 { 788 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 789 struct ieee80211vap *vap = ss->ss_vap; 790 struct ieee80211com *ic = ss->ss_ic; 791 792 IEEE80211_LOCK_ASSERT(ic); 793 794 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: out\n", __func__); 795 796 if (ss_priv->ss_iflags & ISCAN_ABORT) { 797 scan_done(ss, scandone); 798 return; 799 } 800 801 IEEE80211_UNLOCK(ic); 802 ic->ic_scan_end(ic); /* notify driver */ 803 IEEE80211_LOCK(ic); 804 /* XXX scan state can change! Re-validate scan state! */ 805 806 /* 807 * Since a cancellation may have occurred during one of the 808 * driver calls (whilst unlocked), update scandone. 809 */ 810 if ((scandone == 0) && ((ss_priv->ss_iflags & ISCAN_PAUSE) == ISCAN_CANCEL)) { 811 /* XXX printf? */ 812 if_printf(vap->iv_ifp, 813 "%s: OOPS! scan cancelled during driver call (1) (ss_iflags=0x%x)!\n", 814 __func__, 815 ss_priv->ss_iflags); 816 scandone = 1; 817 } 818 819 /* 820 * Record scan complete time. Note that we also do 821 * this when canceled so any background scan will 822 * not be restarted for a while. 823 */ 824 if (scandone) 825 ic->ic_lastscan = ticks; 826 /* return to the bss channel */ 827 if (ic->ic_bsschan != IEEE80211_CHAN_ANYC && 828 ic->ic_curchan != ic->ic_bsschan) { 829 ieee80211_setupcurchan(ic, ic->ic_bsschan); 830 IEEE80211_UNLOCK(ic); 831 ic->ic_set_channel(ic); 832 ieee80211_radiotap_chan_change(ic); 833 IEEE80211_LOCK(ic); 834 } 835 /* clear internal flags and any indication of a pick */ 836 ss_priv->ss_iflags &= ~ISCAN_REP; 837 ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK; 838 839 /* 840 * If not canceled and scan completed, do post-processing. 841 * If the callback function returns 0, then it wants to 842 * continue/restart scanning. Unfortunately we needed to 843 * notify the driver to end the scan above to avoid having 844 * rx frames alter the scan candidate list. 845 */ 846 if ((ss_priv->ss_iflags & ISCAN_CANCEL) == 0 && 847 !ss->ss_ops->scan_end(ss, vap) && 848 (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 && 849 ieee80211_time_before(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) { 850 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 851 "%s: done, restart " 852 "[ticks %u, dwell min %lu scanend %lu]\n", 853 __func__, 854 ticks, ss->ss_mindwell, ss_priv->ss_scanend); 855 ss->ss_next = 0; /* reset to beginning */ 856 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) 857 vap->iv_stats.is_scan_active++; 858 else 859 vap->iv_stats.is_scan_passive++; 860 861 ss->ss_ops->scan_restart(ss, vap); /* XXX? */ 862 ieee80211_runtask(ic, &ss_priv->ss_scan_start); 863 IEEE80211_UNLOCK(ic); 864 return; 865 } 866 867 /* past here, scandone is ``true'' if not in bg mode */ 868 if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0) 869 scandone = 1; 870 871 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 872 "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n", 873 __func__, scandone ? "done" : "stopped", 874 ticks, ss->ss_mindwell, ss_priv->ss_scanend); 875 876 /* 877 * Since a cancellation may have occurred during one of the 878 * driver calls (whilst unlocked), update scandone. 879 */ 880 if (scandone == 0 && (ss_priv->ss_iflags & ISCAN_PAUSE) == ISCAN_CANCEL) { 881 /* XXX printf? */ 882 if_printf(vap->iv_ifp, 883 "%s: OOPS! scan cancelled during driver call (2) (ss_iflags=0x%x)!\n", 884 __func__, 885 ss_priv->ss_iflags); 886 scandone = 1; 887 } 888 889 scan_done(ss, scandone); 890 } 891 892 static void 893 scan_done(struct ieee80211_scan_state *ss, int scandone) 894 { 895 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 896 struct ieee80211com *ic = ss->ss_ic; 897 struct ieee80211vap *vap = ss->ss_vap; 898 899 IEEE80211_LOCK_ASSERT(ic); 900 901 /* 902 * Clear the SCAN bit first in case frames are 903 * pending on the station power save queue. If 904 * we defer this then the dispatch of the frames 905 * may generate a request to cancel scanning. 906 */ 907 ic->ic_flags &= ~IEEE80211_F_SCAN; 908 909 /* 910 * Drop out of power save mode when a scan has 911 * completed. If this scan was prematurely terminated 912 * because it is a background scan then don't notify 913 * the ap; we'll either return to scanning after we 914 * receive the beacon frame or we'll drop out of power 915 * save mode because the beacon indicates we have frames 916 * waiting for us. 917 */ 918 if (scandone) { 919 /* 920 * If we're not a scan offload device, come back out of 921 * station powersave. Offload devices handle this themselves. 922 */ 923 if ((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0) 924 vap->iv_sta_ps(vap, 0); 925 if (ss->ss_next >= ss->ss_last) { 926 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 927 "%s: Dropping out of scan; ss_next=%u, ss_last=%u\n", 928 __func__, 929 (uint32_t) ss->ss_next, 930 (uint32_t) ss->ss_last); 931 ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN; 932 } 933 934 /* send 'scan done' event if not interrupted due to traffic. */ 935 if (!(ss_priv->ss_iflags & ISCAN_INTERRUPT) || 936 (ss->ss_next >= ss->ss_last)) 937 ieee80211_notify_scan_done(vap); 938 } 939 ss_priv->ss_iflags &= ~(ISCAN_PAUSE | ISCAN_ABORT); 940 ss_priv->ss_scanend = 0; 941 ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST); 942 IEEE80211_UNLOCK(ic); 943 #undef ISCAN_REP 944 } 945 946 /* 947 * Process a beacon or probe response frame. 948 */ 949 static void 950 ieee80211_swscan_add_scan(struct ieee80211vap *vap, 951 struct ieee80211_channel *curchan, 952 const struct ieee80211_scanparams *sp, 953 const struct ieee80211_frame *wh, 954 int subtype, int rssi, int noise) 955 { 956 struct ieee80211com *ic = vap->iv_ic; 957 struct ieee80211_scan_state *ss = ic->ic_scan; 958 959 /* XXX locking */ 960 /* 961 * Frames received during startup are discarded to avoid 962 * using scan state setup on the initial entry to the timer 963 * callback. This can occur because the device may enable 964 * rx prior to our doing the initial channel change in the 965 * timer routine. 966 */ 967 if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD) 968 return; 969 #ifdef IEEE80211_DEBUG 970 if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN)) 971 ieee80211_scan_dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi); 972 #endif 973 if (ss->ss_ops != NULL && 974 ss->ss_ops->scan_add(ss, curchan, sp, wh, subtype, rssi, noise)) { 975 /* 976 * If we've reached the min dwell time terminate 977 * the timer so we'll switch to the next channel. 978 */ 979 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 && 980 ieee80211_time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) { 981 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 982 "%s: chan %3d%c min dwell met (%u > %lu)\n", 983 __func__, 984 ieee80211_chan2ieee(ic, ic->ic_curchan), 985 ieee80211_channel_type_char(ic->ic_curchan), 986 ticks, SCAN_PRIVATE(ss)->ss_chanmindwell); 987 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL; 988 /* 989 * NB: trigger at next clock tick or wait for the 990 * hardware. 991 */ 992 ic->ic_scan_mindwell(ss); 993 } 994 } 995 } 996 997 static struct ieee80211_scan_methods swscan_methods = { 998 .sc_attach = ieee80211_swscan_attach, 999 .sc_detach = ieee80211_swscan_detach, 1000 .sc_vattach = ieee80211_swscan_vattach, 1001 .sc_vdetach = ieee80211_swscan_vdetach, 1002 .sc_set_scan_duration = ieee80211_swscan_set_scan_duration, 1003 .sc_start_scan = ieee80211_swscan_start_scan, 1004 .sc_check_scan = ieee80211_swscan_check_scan, 1005 .sc_bg_scan = ieee80211_swscan_bg_scan, 1006 .sc_cancel_scan = ieee80211_swscan_cancel_scan, 1007 .sc_cancel_anyscan = ieee80211_swscan_cancel_anyscan, 1008 .sc_scan_next = ieee80211_swscan_scan_next, 1009 .sc_scan_done = ieee80211_swscan_scan_done, 1010 .sc_scan_probe_curchan = ieee80211_swscan_probe_curchan, 1011 .sc_add_scan = ieee80211_swscan_add_scan 1012 }; 1013 1014 /* 1015 * Default scan attach method. 1016 */ 1017 void 1018 ieee80211_swscan_attach(struct ieee80211com *ic) 1019 { 1020 struct scan_state *ss; 1021 1022 /* 1023 * Setup the default methods 1024 */ 1025 ic->ic_scan_methods = &swscan_methods; 1026 1027 /* Allocate initial scan state */ 1028 ss = (struct scan_state *) IEEE80211_MALLOC(sizeof(struct scan_state), 1029 M_80211_SCAN, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO); 1030 if (ss == NULL) { 1031 ic->ic_scan = NULL; 1032 return; 1033 } 1034 TASK_INIT(&ss->ss_scan_start, 0, scan_start, ss); 1035 TIMEOUT_TASK_INIT(ic->ic_tq, &ss->ss_scan_curchan, 0, 1036 scan_curchan_task, ss); 1037 1038 ic->ic_scan = &ss->base; 1039 ss->base.ss_ic = ic; 1040 1041 ic->ic_scan_curchan = scan_curchan; 1042 ic->ic_scan_mindwell = scan_mindwell; 1043 }
Cache object: f741f71743dab7834155518be51e6703
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