sys/net80211/ieee80211_scan_sw.c

   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 }