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