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 * Start a scan unless one is already going. 237 * 238 * Called without the comlock held; grab the comlock as appropriate. 239 */ 240 static int 241 ieee80211_swscan_start_scan(const struct ieee80211_scanner *scan, 242 struct ieee80211vap *vap, int flags, 243 u_int duration, u_int mindwell, u_int maxdwell, 244 u_int nssid, const struct ieee80211_scan_ssid ssids[]) 245 { 246 struct ieee80211com *ic = vap->iv_ic; 247 int result; 248 249 IEEE80211_UNLOCK_ASSERT(ic); 250 251 IEEE80211_LOCK(ic); 252 result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration, 253 mindwell, maxdwell, nssid, ssids); 254 IEEE80211_UNLOCK(ic); 255 256 return result; 257 } 258 259 /* 260 * Check the scan cache for an ap/channel to use; if that 261 * fails then kick off a new scan. 262 * 263 * Called with the comlock held. 264 * 265 * XXX TODO: split out! 266 */ 267 static int 268 ieee80211_swscan_check_scan(const struct ieee80211_scanner *scan, 269 struct ieee80211vap *vap, int flags, 270 u_int duration, u_int mindwell, u_int maxdwell, 271 u_int nssid, const struct ieee80211_scan_ssid ssids[]) 272 { 273 struct ieee80211com *ic = vap->iv_ic; 274 struct ieee80211_scan_state *ss = ic->ic_scan; 275 int result; 276 277 IEEE80211_LOCK_ASSERT(ic); 278 279 if (ss->ss_ops != NULL) { 280 /* XXX verify ss_ops matches vap->iv_opmode */ 281 if ((flags & IEEE80211_SCAN_NOSSID) == 0) { 282 /* 283 * Update the ssid list and mark flags so if 284 * we call start_scan it doesn't duplicate work. 285 */ 286 ieee80211_scan_copy_ssid(vap, ss, nssid, ssids); 287 flags |= IEEE80211_SCAN_NOSSID; 288 } 289 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 && 290 (flags & IEEE80211_SCAN_FLUSH) == 0 && 291 ieee80211_time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) { 292 /* 293 * We're not currently scanning and the cache is 294 * deemed hot enough to consult. Lock out others 295 * by marking IEEE80211_F_SCAN while we decide if 296 * something is already in the scan cache we can 297 * use. Also discard any frames that might come 298 * in while temporarily marked as scanning. 299 */ 300 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 301 "cache hot; ic_lastscan=%d, scanvalid=%d, ticks=%d\n", 302 ic->ic_lastscan, 303 vap->iv_scanvalid, 304 ticks); 305 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD; 306 ic->ic_flags |= IEEE80211_F_SCAN; 307 308 /* NB: need to use supplied flags in check */ 309 ss->ss_flags = flags & 0xff; 310 result = ss->ss_ops->scan_end(ss, vap); 311 312 ic->ic_flags &= ~IEEE80211_F_SCAN; 313 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD; 314 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 315 "%s: scan_end returned %d\n", __func__, result); 316 if (result) { 317 ieee80211_notify_scan_done(vap); 318 return 1; 319 } 320 } 321 } 322 result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration, 323 mindwell, maxdwell, nssid, ssids); 324 325 return result; 326 } 327 328 /* 329 * Restart a previous scan. If the previous scan completed 330 * then we start again using the existing channel list. 331 */ 332 static int 333 ieee80211_swscan_bg_scan(const struct ieee80211_scanner *scan, 334 struct ieee80211vap *vap, int flags) 335 { 336 struct ieee80211com *ic = vap->iv_ic; 337 struct ieee80211_scan_state *ss = ic->ic_scan; 338 339 /* XXX assert unlocked? */ 340 // IEEE80211_UNLOCK_ASSERT(ic); 341 342 IEEE80211_LOCK(ic); 343 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) { 344 u_int duration; 345 /* 346 * Go off-channel for a fixed interval that is large 347 * enough to catch most ap's but short enough that 348 * we can return on-channel before our listen interval 349 * expires. 350 */ 351 duration = IEEE80211_SCAN_OFFCHANNEL; 352 353 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 354 "%s: %s scan, ticks %u duration %u\n", __func__, 355 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive", 356 ticks, duration); 357 358 ieee80211_scan_update_locked(vap, scan); 359 if (ss->ss_ops != NULL) { 360 ss->ss_vap = vap; 361 /* 362 * A background scan does not select a new sta; it 363 * just refreshes the scan cache. Also, indicate 364 * the scan logic should follow the beacon schedule: 365 * we go off-channel and scan for a while, then 366 * return to the bss channel to receive a beacon, 367 * then go off-channel again. All during this time 368 * we notify the ap we're in power save mode. When 369 * the scan is complete we leave power save mode. 370 * If any beacon indicates there are frames pending 371 * for us then we drop out of power save mode 372 * (and background scan) automatically by way of the 373 * usual sta power save logic. 374 */ 375 ss->ss_flags |= IEEE80211_SCAN_NOPICK 376 | IEEE80211_SCAN_BGSCAN 377 | flags 378 ; 379 /* if previous scan completed, restart */ 380 if (ss->ss_next >= ss->ss_last) { 381 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) 382 vap->iv_stats.is_scan_active++; 383 else 384 vap->iv_stats.is_scan_passive++; 385 /* 386 * NB: beware of the scan cache being flushed; 387 * if the channel list is empty use the 388 * scan_start method to populate it. 389 */ 390 ss->ss_next = 0; 391 if (ss->ss_last != 0) 392 ss->ss_ops->scan_restart(ss, vap); 393 else { 394 ss->ss_ops->scan_start(ss, vap); 395 #ifdef IEEE80211_DEBUG 396 if (ieee80211_msg_scan(vap)) 397 ieee80211_scan_dump(ss); 398 #endif /* IEEE80211_DEBUG */ 399 } 400 } 401 ieee80211_swscan_set_scan_duration(vap, duration); 402 ss->ss_maxdwell = duration; 403 ic->ic_flags |= IEEE80211_F_SCAN; 404 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN; 405 ieee80211_runtask(ic, 406 &SCAN_PRIVATE(ss)->ss_scan_start); 407 } else { 408 /* XXX msg+stat */ 409 } 410 } else { 411 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 412 "%s: %s scan already in progress\n", __func__, 413 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"); 414 } 415 IEEE80211_UNLOCK(ic); 416 417 /* NB: racey, does it matter? */ 418 return (ic->ic_flags & IEEE80211_F_SCAN); 419 } 420 421 /* 422 * Taskqueue work to cancel a scan. 423 * 424 * Note: for offload scan devices, we may want to call into the 425 * driver to try and cancel scanning, however it may not be cancelable. 426 */ 427 static void 428 cancel_scan(struct ieee80211vap *vap, int any, const char *func) 429 { 430 struct ieee80211com *ic = vap->iv_ic; 431 struct ieee80211_scan_state *ss = ic->ic_scan; 432 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 433 int signal; 434 435 IEEE80211_LOCK(ic); 436 signal = any ? ISCAN_PAUSE : ISCAN_CANCEL; 437 if ((ic->ic_flags & IEEE80211_F_SCAN) && 438 (any || ss->ss_vap == vap) && 439 (ss_priv->ss_iflags & signal) == 0) { 440 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 441 "%s: %s %s scan\n", func, 442 any ? "pause" : "cancel", 443 ss->ss_flags & IEEE80211_SCAN_ACTIVE ? 444 "active" : "passive"); 445 446 /* clear bg scan NOPICK */ 447 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK; 448 /* mark request and wake up the scan task */ 449 scan_signal_locked(ss, signal); 450 } else { 451 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 452 "%s: called; F_SCAN=%d, vap=%s, signal=%d\n", 453 func, 454 !! (ic->ic_flags & IEEE80211_F_SCAN), 455 (ss->ss_vap == vap ? "match" : "nomatch"), 456 !! (ss_priv->ss_iflags & signal)); 457 } 458 IEEE80211_UNLOCK(ic); 459 } 460 461 /* 462 * Cancel any scan currently going on for the specified vap. 463 */ 464 static void 465 ieee80211_swscan_cancel_scan(struct ieee80211vap *vap) 466 { 467 cancel_scan(vap, 0, __func__); 468 } 469 470 /* 471 * Cancel any scan currently going on. 472 */ 473 static void 474 ieee80211_swscan_cancel_anyscan(struct ieee80211vap *vap) 475 { 476 477 /* XXX for now - just don't do this per packet. */ 478 if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) 479 return; 480 481 cancel_scan(vap, 1, __func__); 482 } 483 484 /* 485 * Manually switch to the next channel in the channel list. 486 * Provided for drivers that manage scanning themselves 487 * (e.g. for firmware-based devices). 488 */ 489 static void 490 ieee80211_swscan_scan_next(struct ieee80211vap *vap) 491 { 492 struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan; 493 494 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__); 495 496 /* wake up the scan task */ 497 scan_signal(ss, 0); 498 } 499 500 /* 501 * Manually stop a scan that is currently running. 502 * Provided for drivers that are not able to scan single channels 503 * (e.g. for firmware-based devices). 504 */ 505 static void 506 ieee80211_swscan_scan_done(struct ieee80211vap *vap) 507 { 508 struct ieee80211com *ic = vap->iv_ic; 509 struct ieee80211_scan_state *ss = ic->ic_scan; 510 511 IEEE80211_LOCK_ASSERT(ic); 512 513 scan_signal_locked(ss, 0); 514 } 515 516 /* 517 * Probe the current channel, if allowed, while scanning. 518 * If the channel is not marked passive-only then send 519 * a probe request immediately. Otherwise mark state and 520 * listen for beacons on the channel; if we receive something 521 * then we'll transmit a probe request. 522 */ 523 static void 524 ieee80211_swscan_probe_curchan(struct ieee80211vap *vap, int force) 525 { 526 struct ieee80211com *ic = vap->iv_ic; 527 struct ieee80211_scan_state *ss = ic->ic_scan; 528 struct ifnet *ifp = vap->iv_ifp; 529 int i; 530 531 /* 532 * Full-offload scan devices don't require this. 533 */ 534 if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) 535 return; 536 537 /* 538 * Send directed probe requests followed by any 539 * broadcast probe request. 540 * XXX remove dependence on ic/vap->iv_bss 541 */ 542 for (i = 0; i < ss->ss_nssid; i++) 543 ieee80211_send_probereq(vap->iv_bss, 544 vap->iv_myaddr, ifp->if_broadcastaddr, 545 ifp->if_broadcastaddr, 546 ss->ss_ssid[i].ssid, ss->ss_ssid[i].len); 547 if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0) 548 ieee80211_send_probereq(vap->iv_bss, 549 vap->iv_myaddr, ifp->if_broadcastaddr, 550 ifp->if_broadcastaddr, 551 "", 0); 552 } 553 554 /* 555 * Scan curchan. If this is an active scan and the channel 556 * is not marked passive then send probe request frame(s). 557 * Arrange for the channel change after maxdwell ticks. 558 */ 559 static void 560 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell) 561 { 562 struct ieee80211vap *vap = ss->ss_vap; 563 struct ieee80211com *ic = ss->ss_ic; 564 565 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 566 "%s: calling; maxdwell=%lu\n", 567 __func__, 568 maxdwell); 569 IEEE80211_LOCK(ic); 570 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) 571 ieee80211_probe_curchan(vap, 0); 572 taskqueue_enqueue_timeout(ic->ic_tq, 573 &SCAN_PRIVATE(ss)->ss_scan_curchan, maxdwell); 574 IEEE80211_UNLOCK(ic); 575 } 576 577 static void 578 scan_signal(struct ieee80211_scan_state *ss, int iflags) 579 { 580 struct ieee80211com *ic = ss->ss_ic; 581 582 IEEE80211_UNLOCK_ASSERT(ic); 583 584 IEEE80211_LOCK(ic); 585 scan_signal_locked(ss, iflags); 586 IEEE80211_UNLOCK(ic); 587 } 588 589 static void 590 scan_signal_locked(struct ieee80211_scan_state *ss, int iflags) 591 { 592 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 593 struct timeout_task *scan_task = &ss_priv->ss_scan_curchan; 594 struct ieee80211com *ic = ss->ss_ic; 595 596 IEEE80211_LOCK_ASSERT(ic); 597 598 ss_priv->ss_iflags |= iflags; 599 if (ss_priv->ss_iflags & ISCAN_RUNNING) { 600 if (taskqueue_cancel_timeout(ic->ic_tq, scan_task, NULL) == 0) 601 taskqueue_enqueue_timeout(ic->ic_tq, scan_task, 0); 602 } 603 } 604 605 /* 606 * Handle mindwell requirements completed; initiate a channel 607 * change to the next channel asap. 608 */ 609 static void 610 scan_mindwell(struct ieee80211_scan_state *ss) 611 { 612 613 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: called\n", 614 __func__); 615 616 scan_signal(ss, 0); 617 } 618 619 static void 620 scan_start(void *arg, int pending) 621 { 622 #define ISCAN_REP (ISCAN_MINDWELL | ISCAN_DISCARD) 623 struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg; 624 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 625 struct ieee80211vap *vap = ss->ss_vap; 626 struct ieee80211com *ic = ss->ss_ic; 627 628 IEEE80211_LOCK(ic); 629 if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 || 630 (ss_priv->ss_iflags & ISCAN_ABORT)) { 631 /* Cancelled before we started */ 632 scan_done(ss, 0); 633 return; 634 } 635 636 if (ss->ss_next == ss->ss_last) { 637 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 638 "%s: no channels to scan\n", __func__); 639 scan_done(ss, 1); 640 return; 641 } 642 643 /* 644 * Put the station into power save mode. 645 * 646 * This is only required if we're not a full-offload devices; 647 * those devices manage scan/traffic differently. 648 */ 649 if (((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0) && 650 vap->iv_opmode == IEEE80211_M_STA && 651 vap->iv_state == IEEE80211_S_RUN) { 652 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) { 653 /* Enable station power save mode */ 654 vap->iv_sta_ps(vap, 1); 655 /* Wait until null data frame will be ACK'ed */ 656 mtx_sleep(vap, IEEE80211_LOCK_OBJ(ic), PCATCH, 657 "sta_ps", msecs_to_ticks(10)); 658 if (ss_priv->ss_iflags & ISCAN_ABORT) { 659 scan_done(ss, 0); 660 return; 661 } 662 } 663 } 664 665 ss_priv->ss_scanend = ticks + ss_priv->ss_duration; 666 667 /* XXX scan state can change! Re-validate scan state! */ 668 669 IEEE80211_UNLOCK(ic); 670 671 ic->ic_scan_start(ic); /* notify driver */ 672 673 scan_curchan_task(ss, 0); 674 } 675 676 static void 677 scan_curchan_task(void *arg, int pending) 678 { 679 struct ieee80211_scan_state *ss = arg; 680 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 681 struct ieee80211com *ic = ss->ss_ic; 682 struct ieee80211_channel *chan; 683 unsigned long maxdwell; 684 int scandone, scanstop; 685 686 IEEE80211_LOCK(ic); 687 end: 688 /* 689 * Note: only /end/ the scan if we're CANCEL rather than 690 * CANCEL+INTERRUPT (ie, 'PAUSE'). 691 * 692 * We can stop the scan if we hit cancel, but we shouldn't 693 * call scan_end(ss, 1) if we're just PAUSEing the scan. 694 */ 695 scandone = (ss->ss_next >= ss->ss_last) || 696 ((ss_priv->ss_iflags & ISCAN_PAUSE) == ISCAN_CANCEL); 697 scanstop = (ss->ss_next >= ss->ss_last) || 698 ((ss_priv->ss_iflags & ISCAN_CANCEL) != 0); 699 700 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, 701 "%s: loop start; scandone=%d, scanstop=%d, ss_iflags=0x%x, ss_next=%u, ss_last=%u\n", 702 __func__, 703 scandone, 704 scanstop, 705 (uint32_t) ss_priv->ss_iflags, 706 (uint32_t) ss->ss_next, 707 (uint32_t) ss->ss_last); 708 709 if (scanstop || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) || 710 (ss_priv->ss_iflags & ISCAN_ABORT) || 711 ieee80211_time_after(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) { 712 ss_priv->ss_iflags &= ~ISCAN_RUNNING; 713 scan_end(ss, scandone); 714 return; 715 } else 716 ss_priv->ss_iflags |= ISCAN_RUNNING; 717 718 chan = ss->ss_chans[ss->ss_next++]; 719 720 /* 721 * Watch for truncation due to the scan end time. 722 */ 723 if (ieee80211_time_after(ticks + ss->ss_maxdwell, ss_priv->ss_scanend)) 724 maxdwell = ss_priv->ss_scanend - ticks; 725 else 726 maxdwell = ss->ss_maxdwell; 727 728 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, 729 "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n", 730 __func__, 731 ieee80211_chan2ieee(ic, ic->ic_curchan), 732 ieee80211_channel_type_char(ic->ic_curchan), 733 ieee80211_chan2ieee(ic, chan), 734 ieee80211_channel_type_char(chan), 735 (ss->ss_flags & IEEE80211_SCAN_ACTIVE) && 736 (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ? 737 "active" : "passive", 738 ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell)); 739 740 /* 741 * Potentially change channel and phy mode. 742 */ 743 ic->ic_curchan = chan; 744 ic->ic_rt = ieee80211_get_ratetable(chan); 745 IEEE80211_UNLOCK(ic); 746 /* 747 * Perform the channel change and scan unlocked so the driver 748 * may sleep. Once set_channel returns the hardware has 749 * completed the channel change. 750 */ 751 ic->ic_set_channel(ic); 752 ieee80211_radiotap_chan_change(ic); 753 754 /* 755 * Scan curchan. Drivers for "intelligent hardware" 756 * override ic_scan_curchan to tell the device to do 757 * the work. Otherwise we manage the work ourselves; 758 * sending a probe request (as needed), and arming the 759 * timeout to switch channels after maxdwell ticks. 760 * 761 * scan_curchan should only pause for the time required to 762 * prepare/initiate the hardware for the scan (if at all). 763 */ 764 ic->ic_scan_curchan(ss, maxdwell); 765 IEEE80211_LOCK(ic); 766 767 /* XXX scan state can change! Re-validate scan state! */ 768 769 ss_priv->ss_chanmindwell = ticks + ss->ss_mindwell; 770 /* clear mindwell lock and initial channel change flush */ 771 ss_priv->ss_iflags &= ~ISCAN_REP; 772 773 if (ss_priv->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)) { 774 taskqueue_cancel_timeout(ic->ic_tq, &ss_priv->ss_scan_curchan, 775 NULL); 776 goto end; 777 } 778 779 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: waiting\n", 780 __func__); 781 IEEE80211_UNLOCK(ic); 782 } 783 784 static void 785 scan_end(struct ieee80211_scan_state *ss, int scandone) 786 { 787 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 788 struct ieee80211vap *vap = ss->ss_vap; 789 struct ieee80211com *ic = ss->ss_ic; 790 791 IEEE80211_LOCK_ASSERT(ic); 792 793 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: out\n", __func__); 794 795 if (ss_priv->ss_iflags & ISCAN_ABORT) { 796 scan_done(ss, scandone); 797 return; 798 } 799 800 IEEE80211_UNLOCK(ic); 801 ic->ic_scan_end(ic); /* notify driver */ 802 IEEE80211_LOCK(ic); 803 /* XXX scan state can change! Re-validate scan state! */ 804 805 /* 806 * Since a cancellation may have occurred during one of the 807 * driver calls (whilst unlocked), update scandone. 808 */ 809 if ((scandone == 0) && ((ss_priv->ss_iflags & ISCAN_PAUSE) == ISCAN_CANCEL)) { 810 /* XXX printf? */ 811 if_printf(vap->iv_ifp, 812 "%s: OOPS! scan cancelled during driver call (1) (ss_iflags=0x%x)!\n", 813 __func__, 814 ss_priv->ss_iflags); 815 scandone = 1; 816 } 817 818 /* 819 * Record scan complete time. Note that we also do 820 * this when canceled so any background scan will 821 * not be restarted for a while. 822 */ 823 if (scandone) 824 ic->ic_lastscan = ticks; 825 /* return to the bss channel */ 826 if (ic->ic_bsschan != IEEE80211_CHAN_ANYC && 827 ic->ic_curchan != ic->ic_bsschan) { 828 ieee80211_setupcurchan(ic, ic->ic_bsschan); 829 IEEE80211_UNLOCK(ic); 830 ic->ic_set_channel(ic); 831 ieee80211_radiotap_chan_change(ic); 832 IEEE80211_LOCK(ic); 833 } 834 /* clear internal flags and any indication of a pick */ 835 ss_priv->ss_iflags &= ~ISCAN_REP; 836 ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK; 837 838 /* 839 * If not canceled and scan completed, do post-processing. 840 * If the callback function returns 0, then it wants to 841 * continue/restart scanning. Unfortunately we needed to 842 * notify the driver to end the scan above to avoid having 843 * rx frames alter the scan candidate list. 844 */ 845 if ((ss_priv->ss_iflags & ISCAN_CANCEL) == 0 && 846 !ss->ss_ops->scan_end(ss, vap) && 847 (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 && 848 ieee80211_time_before(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) { 849 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 850 "%s: done, restart " 851 "[ticks %u, dwell min %lu scanend %lu]\n", 852 __func__, 853 ticks, ss->ss_mindwell, ss_priv->ss_scanend); 854 ss->ss_next = 0; /* reset to beginning */ 855 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) 856 vap->iv_stats.is_scan_active++; 857 else 858 vap->iv_stats.is_scan_passive++; 859 860 ss->ss_ops->scan_restart(ss, vap); /* XXX? */ 861 ieee80211_runtask(ic, &ss_priv->ss_scan_start); 862 IEEE80211_UNLOCK(ic); 863 return; 864 } 865 866 /* past here, scandone is ``true'' if not in bg mode */ 867 if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0) 868 scandone = 1; 869 870 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 871 "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n", 872 __func__, scandone ? "done" : "stopped", 873 ticks, ss->ss_mindwell, ss_priv->ss_scanend); 874 875 /* 876 * Since a cancellation may have occurred during one of the 877 * driver calls (whilst unlocked), update scandone. 878 */ 879 if (scandone == 0 && (ss_priv->ss_iflags & ISCAN_PAUSE) == ISCAN_CANCEL) { 880 /* XXX printf? */ 881 if_printf(vap->iv_ifp, 882 "%s: OOPS! scan cancelled during driver call (2) (ss_iflags=0x%x)!\n", 883 __func__, 884 ss_priv->ss_iflags); 885 scandone = 1; 886 } 887 888 scan_done(ss, scandone); 889 } 890 891 static void 892 scan_done(struct ieee80211_scan_state *ss, int scandone) 893 { 894 struct scan_state *ss_priv = SCAN_PRIVATE(ss); 895 struct ieee80211com *ic = ss->ss_ic; 896 struct ieee80211vap *vap = ss->ss_vap; 897 898 IEEE80211_LOCK_ASSERT(ic); 899 900 /* 901 * Clear the SCAN bit first in case frames are 902 * pending on the station power save queue. If 903 * we defer this then the dispatch of the frames 904 * may generate a request to cancel scanning. 905 */ 906 ic->ic_flags &= ~IEEE80211_F_SCAN; 907 908 /* 909 * Drop out of power save mode when a scan has 910 * completed. If this scan was prematurely terminated 911 * because it is a background scan then don't notify 912 * the ap; we'll either return to scanning after we 913 * receive the beacon frame or we'll drop out of power 914 * save mode because the beacon indicates we have frames 915 * waiting for us. 916 */ 917 if (scandone) { 918 /* 919 * If we're not a scan offload device, come back out of 920 * station powersave. Offload devices handle this themselves. 921 */ 922 if ((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0) 923 vap->iv_sta_ps(vap, 0); 924 if (ss->ss_next >= ss->ss_last) { 925 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 926 "%s: Dropping out of scan; ss_next=%u, ss_last=%u\n", 927 __func__, 928 (uint32_t) ss->ss_next, 929 (uint32_t) ss->ss_last); 930 ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN; 931 } 932 933 /* send 'scan done' event if not interrupted due to traffic. */ 934 if (!(ss_priv->ss_iflags & ISCAN_INTERRUPT) || 935 (ss->ss_next >= ss->ss_last)) 936 ieee80211_notify_scan_done(vap); 937 } 938 ss_priv->ss_iflags &= ~(ISCAN_PAUSE | ISCAN_ABORT); 939 ss_priv->ss_scanend = 0; 940 ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST); 941 IEEE80211_UNLOCK(ic); 942 #undef ISCAN_REP 943 } 944 945 /* 946 * Process a beacon or probe response frame. 947 */ 948 static void 949 ieee80211_swscan_add_scan(struct ieee80211vap *vap, 950 struct ieee80211_channel *curchan, 951 const struct ieee80211_scanparams *sp, 952 const struct ieee80211_frame *wh, 953 int subtype, int rssi, int noise) 954 { 955 struct ieee80211com *ic = vap->iv_ic; 956 struct ieee80211_scan_state *ss = ic->ic_scan; 957 958 /* XXX locking */ 959 /* 960 * Frames received during startup are discarded to avoid 961 * using scan state setup on the initial entry to the timer 962 * callback. This can occur because the device may enable 963 * rx prior to our doing the initial channel change in the 964 * timer routine. 965 */ 966 if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD) 967 return; 968 #ifdef IEEE80211_DEBUG 969 if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN)) 970 ieee80211_scan_dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi); 971 #endif 972 if (ss->ss_ops != NULL && 973 ss->ss_ops->scan_add(ss, curchan, sp, wh, subtype, rssi, noise)) { 974 /* 975 * If we've reached the min dwell time terminate 976 * the timer so we'll switch to the next channel. 977 */ 978 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 && 979 ieee80211_time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) { 980 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 981 "%s: chan %3d%c min dwell met (%u > %lu)\n", 982 __func__, 983 ieee80211_chan2ieee(ic, ic->ic_curchan), 984 ieee80211_channel_type_char(ic->ic_curchan), 985 ticks, SCAN_PRIVATE(ss)->ss_chanmindwell); 986 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL; 987 /* 988 * NB: trigger at next clock tick or wait for the 989 * hardware. 990 */ 991 ic->ic_scan_mindwell(ss); 992 } 993 } 994 } 995 996 static struct ieee80211_scan_methods swscan_methods = { 997 .sc_attach = ieee80211_swscan_attach, 998 .sc_detach = ieee80211_swscan_detach, 999 .sc_vattach = ieee80211_swscan_vattach, 1000 .sc_vdetach = ieee80211_swscan_vdetach, 1001 .sc_set_scan_duration = ieee80211_swscan_set_scan_duration, 1002 .sc_start_scan = ieee80211_swscan_start_scan, 1003 .sc_check_scan = ieee80211_swscan_check_scan, 1004 .sc_bg_scan = ieee80211_swscan_bg_scan, 1005 .sc_cancel_scan = ieee80211_swscan_cancel_scan, 1006 .sc_cancel_anyscan = ieee80211_swscan_cancel_anyscan, 1007 .sc_scan_next = ieee80211_swscan_scan_next, 1008 .sc_scan_done = ieee80211_swscan_scan_done, 1009 .sc_scan_probe_curchan = ieee80211_swscan_probe_curchan, 1010 .sc_add_scan = ieee80211_swscan_add_scan 1011 }; 1012 1013 /* 1014 * Default scan attach method. 1015 */ 1016 void 1017 ieee80211_swscan_attach(struct ieee80211com *ic) 1018 { 1019 struct scan_state *ss; 1020 1021 /* 1022 * Setup the default methods 1023 */ 1024 ic->ic_scan_methods = &swscan_methods; 1025 1026 /* Allocate initial scan state */ 1027 ss = (struct scan_state *) IEEE80211_MALLOC(sizeof(struct scan_state), 1028 M_80211_SCAN, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO); 1029 if (ss == NULL) { 1030 ic->ic_scan = NULL; 1031 return; 1032 } 1033 TASK_INIT(&ss->ss_scan_start, 0, scan_start, ss); 1034 TIMEOUT_TASK_INIT(ic->ic_tq, &ss->ss_scan_curchan, 0, 1035 scan_curchan_task, ss); 1036 1037 ic->ic_scan = &ss->base; 1038 ss->base.ss_ic = ic; 1039 1040 ic->ic_scan_curchan = scan_curchan; 1041 ic->ic_scan_mindwell = scan_mindwell; 1042 }
Cache object: 9da60e93024439d4827058e6b00a18d5
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