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_CANCEL    0x0004          /* cancel current scan */
  61 #define ISCAN_ABORT     0x0008          /* end the scan immediately */
  62 #define ISCAN_RUNNING   0x0010          /* scan was started */
  63         unsigned long   ss_chanmindwell;        /* min dwell on curchan */
  64         unsigned long   ss_scanend;             /* time scan must stop */
  65         u_int           ss_duration;            /* duration for next scan */
  66         struct task     ss_scan_start;          /* scan start */
  67         struct timeout_task ss_scan_curchan;    /* scan execution */
  68 };
  69 #define SCAN_PRIVATE(ss)        ((struct scan_state *) ss)
  70
  71 /*
  72  * Amount of time to go off-channel during a background
  73  * scan.  This value should be large enough to catch most
  74  * ap's but short enough that we can return on-channel
  75  * before our listen interval expires.
  76  *
  77  * XXX tunable
  78  * XXX check against configured listen interval
  79  */
  80 #define IEEE80211_SCAN_OFFCHANNEL       msecs_to_ticks(150)
  81
  82 /*
  83  * Roaming-related defaults.  RSSI thresholds are as returned by the
  84  * driver (.5dBm).  Transmit rate thresholds are IEEE rate codes (i.e
  85  * .5M units) or MCS.
  86  */
  87 /* rssi thresholds */
  88 #define ROAM_RSSI_11A_DEFAULT           14      /* 11a bss */
  89 #define ROAM_RSSI_11B_DEFAULT           14      /* 11b bss */
  90 #define ROAM_RSSI_11BONLY_DEFAULT       14      /* 11b-only bss */
  91 /* transmit rate thresholds */
  92 #define ROAM_RATE_11A_DEFAULT           2*12    /* 11a bss */
  93 #define ROAM_RATE_11B_DEFAULT           2*5     /* 11b bss */
  94 #define ROAM_RATE_11BONLY_DEFAULT       2*1     /* 11b-only bss */
  95 #define ROAM_RATE_HALF_DEFAULT          2*6     /* half-width 11a/g bss */
  96 #define ROAM_RATE_QUARTER_DEFAULT       2*3     /* quarter-width 11a/g bss */
  97 #define ROAM_MCS_11N_DEFAULT            (1 | IEEE80211_RATE_MCS) /* 11n bss */
  98
  99 static  void scan_curchan(struct ieee80211_scan_state *, unsigned long);
 100 static  void scan_mindwell(struct ieee80211_scan_state *);
 101 static  void scan_signal(void *);
 102 static  void scan_start(void *, int);
 103 static  void scan_curchan_task(void *, int);
 104 static  void scan_end(struct ieee80211_scan_state *, int);
 105 static  void scan_done(struct ieee80211_scan_state *, int);
 106
 107 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
 108
 109 static void
 110 ieee80211_swscan_detach(struct ieee80211com *ic)
 111 {
 112         struct ieee80211_scan_state *ss = ic->ic_scan;
 113
 114         if (ss != NULL) {
 115                 IEEE80211_LOCK(ic);
 116                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
 117                 scan_signal(ss);
 118                 IEEE80211_UNLOCK(ic);
 119                 ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_start);
 120                 taskqueue_drain_timeout(ic->ic_tq,
 121                     &SCAN_PRIVATE(ss)->ss_scan_curchan);
 122                 KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0,
 123                     ("scan still running"));
 124
 125                 /*
 126                  * For now, do the ss_ops detach here rather
 127                  * than ieee80211_scan_detach().
 128                  *
 129                  * I'll figure out how to cleanly split things up
 130                  * at a later date.
 131                  */
 132                 if (ss->ss_ops != NULL) {
 133                         ss->ss_ops->scan_detach(ss);
 134                         ss->ss_ops = NULL;
 135                 }
 136                 ic->ic_scan = NULL;
 137                 IEEE80211_FREE(SCAN_PRIVATE(ss), M_80211_SCAN);
 138         }
 139 }
 140
 141 static void
 142 ieee80211_swscan_vattach(struct ieee80211vap *vap)
 143 {
 144         /* nothing to do for now */
 145         /*
 146          * TODO: all of the vap scan calls should be methods!
 147          */
 148
 149 }
 150
 151 static void
 152 ieee80211_swscan_vdetach(struct ieee80211vap *vap)
 153 {
 154         struct ieee80211com *ic = vap->iv_ic;
 155         struct ieee80211_scan_state *ss;
 156
 157         IEEE80211_LOCK_ASSERT(ic);
 158         ss = ic->ic_scan;
 159         if (ss != NULL && ss->ss_vap == vap) {
 160                 if (ic->ic_flags & IEEE80211_F_SCAN) {
 161                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
 162                         scan_signal(ss);
 163                 }
 164         }
 165 }
 166
 167 static void
 168 ieee80211_swscan_set_scan_duration(struct ieee80211vap *vap, u_int duration)
 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         /* NB: flush frames rx'd before 1st channel change */
 176         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
 177         SCAN_PRIVATE(ss)->ss_duration = duration;
 178 }
 179
 180 /*
 181  * Start a scan unless one is already going.
 182  */
 183 static int
 184 ieee80211_swscan_start_scan_locked(const struct ieee80211_scanner *scan,
 185         struct ieee80211vap *vap, int flags, u_int duration,
 186         u_int mindwell, u_int maxdwell,
 187         u_int nssid, const struct ieee80211_scan_ssid ssids[])
 188 {
 189         struct ieee80211com *ic = vap->iv_ic;
 190         struct ieee80211_scan_state *ss = ic->ic_scan;
 191
 192         IEEE80211_LOCK_ASSERT(ic);
 193
 194         if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
 195                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 196                     "%s: scan inhibited by pending channel change\n", __func__);
 197         } else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
 198                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 199                     "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
 200                     , __func__
 201                     , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
 202                     , duration, mindwell, maxdwell
 203                     , ieee80211_phymode_name[vap->iv_des_mode]
 204                     , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
 205                     , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
 206                     , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
 207                     , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
 208                     , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
 209                     , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
 210                 );
 211
 212                 ieee80211_scan_update_locked(vap, scan);
 213                 if (ss->ss_ops != NULL) {
 214                         if ((flags & IEEE80211_SCAN_NOSSID) == 0)
 215                                 ieee80211_scan_copy_ssid(vap, ss, nssid, ssids);
 216
 217                         /* NB: top 4 bits for internal use */
 218                         ss->ss_flags = flags & 0xfff;
 219                         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 220                                 vap->iv_stats.is_scan_active++;
 221                         else
 222                                 vap->iv_stats.is_scan_passive++;
 223                         if (flags & IEEE80211_SCAN_FLUSH)
 224                                 ss->ss_ops->scan_flush(ss);
 225                         if (flags & IEEE80211_SCAN_BGSCAN)
 226                                 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
 227
 228                         /* Set duration for this particular scan */
 229                         ieee80211_swscan_set_scan_duration(vap, duration);
 230
 231                         ss->ss_next = 0;
 232                         ss->ss_mindwell = mindwell;
 233                         ss->ss_maxdwell = maxdwell;
 234                         /* NB: scan_start must be before the scan runtask */
 235                         ss->ss_ops->scan_start(ss, vap);
 236 #ifdef IEEE80211_DEBUG
 237                         if (ieee80211_msg_scan(vap))
 238                                 ieee80211_scan_dump(ss);
 239 #endif /* IEEE80211_DEBUG */
 240                         ic->ic_flags |= IEEE80211_F_SCAN;
 241
 242                         /* Start scan task */
 243                         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_start);
 244                 }
 245                 return 1;
 246         } else {
 247                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 248                     "%s: %s scan already in progress\n", __func__,
 249                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
 250         }
 251         return 0;
 252 }
 253
 254
 255 /*
 256  * Start a scan unless one is already going.
 257  *
 258  * Called without the comlock held; grab the comlock as appropriate.
 259  */
 260 static int
 261 ieee80211_swscan_start_scan(const struct ieee80211_scanner *scan,
 262     struct ieee80211vap *vap, int flags,
 263     u_int duration, u_int mindwell, u_int maxdwell,
 264     u_int nssid, const struct ieee80211_scan_ssid ssids[])
 265 {
 266         struct ieee80211com *ic = vap->iv_ic;
 267         int result;
 268
 269         IEEE80211_UNLOCK_ASSERT(ic);
 270
 271         IEEE80211_LOCK(ic);
 272         result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration,
 273             mindwell, maxdwell, nssid, ssids);
 274         IEEE80211_UNLOCK(ic);
 275
 276         return result;
 277 }
 278
 279 /*
 280  * Check the scan cache for an ap/channel to use; if that
 281  * fails then kick off a new scan.
 282  *
 283  * Called with the comlock held.
 284  *
 285  * XXX TODO: split out!
 286  */
 287 static int
 288 ieee80211_swscan_check_scan(const struct ieee80211_scanner *scan,
 289     struct ieee80211vap *vap, int flags,
 290     u_int duration, u_int mindwell, u_int maxdwell,
 291     u_int nssid, const struct ieee80211_scan_ssid ssids[])
 292 {
 293         struct ieee80211com *ic = vap->iv_ic;
 294         struct ieee80211_scan_state *ss = ic->ic_scan;
 295         int result;
 296
 297         IEEE80211_LOCK_ASSERT(ic);
 298
 299         if (ss->ss_ops != NULL) {
 300                 /* XXX verify ss_ops matches vap->iv_opmode */
 301                 if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
 302                         /*
 303                          * Update the ssid list and mark flags so if
 304                          * we call start_scan it doesn't duplicate work.
 305                          */
 306                         ieee80211_scan_copy_ssid(vap, ss, nssid, ssids);
 307                         flags |= IEEE80211_SCAN_NOSSID;
 308                 }
 309                 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
 310                     (flags & IEEE80211_SCAN_FLUSH) == 0 &&
 311                     time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
 312                         /*
 313                          * We're not currently scanning and the cache is
 314                          * deemed hot enough to consult.  Lock out others
 315                          * by marking IEEE80211_F_SCAN while we decide if
 316                          * something is already in the scan cache we can
 317                          * use.  Also discard any frames that might come
 318                          * in while temporarily marked as scanning.
 319                          */
 320                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
 321                         ic->ic_flags |= IEEE80211_F_SCAN;
 322
 323                         /* NB: need to use supplied flags in check */
 324                         ss->ss_flags = flags & 0xff;
 325                         result = ss->ss_ops->scan_end(ss, vap);
 326
 327                         ic->ic_flags &= ~IEEE80211_F_SCAN;
 328                         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
 329                         if (result) {
 330                                 ieee80211_notify_scan_done(vap);
 331                                 return 1;
 332                         }
 333                 }
 334         }
 335         result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration,
 336             mindwell, maxdwell, nssid, ssids);
 337
 338         return result;
 339 }
 340
 341 /*
 342  * Restart a previous scan.  If the previous scan completed
 343  * then we start again using the existing channel list.
 344  */
 345 static int
 346 ieee80211_swscan_bg_scan(const struct ieee80211_scanner *scan,
 347     struct ieee80211vap *vap, int flags)
 348 {
 349         struct ieee80211com *ic = vap->iv_ic;
 350         struct ieee80211_scan_state *ss = ic->ic_scan;
 351
 352         /* XXX assert unlocked? */
 353         // IEEE80211_UNLOCK_ASSERT(ic);
 354
 355         IEEE80211_LOCK(ic);
 356         if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
 357                 u_int duration;
 358                 /*
 359                  * Go off-channel for a fixed interval that is large
 360                  * enough to catch most ap's but short enough that
 361                  * we can return on-channel before our listen interval
 362                  * expires.
 363                  */
 364                 duration = IEEE80211_SCAN_OFFCHANNEL;
 365
 366                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 367                     "%s: %s scan, ticks %u duration %u\n", __func__,
 368                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
 369                     ticks, duration);
 370
 371                 ieee80211_scan_update_locked(vap, scan);
 372                 if (ss->ss_ops != NULL) {
 373                         ss->ss_vap = vap;
 374                         /*
 375                          * A background scan does not select a new sta; it
 376                          * just refreshes the scan cache.  Also, indicate
 377                          * the scan logic should follow the beacon schedule:
 378                          * we go off-channel and scan for a while, then
 379                          * return to the bss channel to receive a beacon,
 380                          * then go off-channel again.  All during this time
 381                          * we notify the ap we're in power save mode.  When
 382                          * the scan is complete we leave power save mode.
 383                          * If any beacon indicates there are frames pending
 384                          * for us then we drop out of power save mode
 385                          * (and background scan) automatically by way of the
 386                          * usual sta power save logic.
 387                          */
 388                         ss->ss_flags |= IEEE80211_SCAN_NOPICK
 389                                      |  IEEE80211_SCAN_BGSCAN
 390                                      |  flags
 391                                      ;
 392                         /* if previous scan completed, restart */
 393                         if (ss->ss_next >= ss->ss_last) {
 394                                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 395                                         vap->iv_stats.is_scan_active++;
 396                                 else
 397                                         vap->iv_stats.is_scan_passive++;
 398                                 /*
 399                                  * NB: beware of the scan cache being flushed;
 400                                  *     if the channel list is empty use the
 401                                  *     scan_start method to populate it.
 402                                  */
 403                                 ss->ss_next = 0;
 404                                 if (ss->ss_last != 0)
 405                                         ss->ss_ops->scan_restart(ss, vap);
 406                                 else {
 407                                         ss->ss_ops->scan_start(ss, vap);
 408 #ifdef IEEE80211_DEBUG
 409                                         if (ieee80211_msg_scan(vap))
 410                                                 ieee80211_scan_dump(ss);
 411 #endif /* IEEE80211_DEBUG */
 412                                 }
 413                         }
 414                         ieee80211_swscan_set_scan_duration(vap, duration);
 415                         ss->ss_maxdwell = duration;
 416                         ic->ic_flags |= IEEE80211_F_SCAN;
 417                         ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
 418                         ieee80211_runtask(ic,
 419                             &SCAN_PRIVATE(ss)->ss_scan_start);
 420                 } else {
 421                         /* XXX msg+stat */
 422                 }
 423         } else {
 424                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 425                     "%s: %s scan already in progress\n", __func__,
 426                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
 427         }
 428         IEEE80211_UNLOCK(ic);
 429
 430         /* NB: racey, does it matter? */
 431         return (ic->ic_flags & IEEE80211_F_SCAN);
 432 }
 433
 434 static void
 435 cancel_scan(struct ieee80211vap *vap, int any, const char *func)
 436 {
 437         struct ieee80211com *ic = vap->iv_ic;
 438         struct ieee80211_scan_state *ss = ic->ic_scan;
 439
 440         IEEE80211_LOCK(ic);
 441         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
 442             (any || ss->ss_vap == vap) &&
 443             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
 444                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 445                     "%s: cancel %s scan\n", func,
 446                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
 447                         "active" : "passive");
 448
 449                 /* clear bg scan NOPICK and mark cancel request */
 450                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
 451                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
 452                 /* wake up the scan task */
 453                 scan_signal(ss);
 454         } else {
 455                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 456                     "%s: called; F_SCAN=%d, vap=%s, CANCEL=%d\n",
 457                         func,
 458                         !! (ic->ic_flags & IEEE80211_F_SCAN),
 459                         (ss->ss_vap == vap ? "match" : "nomatch"),
 460                         !! (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL));
 461         }
 462         IEEE80211_UNLOCK(ic);
 463 }
 464
 465 /*
 466  * Cancel any scan currently going on for the specified vap.
 467  */
 468 static void
 469 ieee80211_swscan_cancel_scan(struct ieee80211vap *vap)
 470 {
 471         cancel_scan(vap, 0, __func__);
 472 }
 473
 474 /*
 475  * Cancel any scan currently going on.
 476  */
 477 static void
 478 ieee80211_swscan_cancel_anyscan(struct ieee80211vap *vap)
 479 {
 480         cancel_scan(vap, 1, __func__);
 481 }
 482
 483 /*
 484  * Public access to scan_next for drivers that manage
 485  * scanning themselves (e.g. for firmware-based devices).
 486  */
 487 static void
 488 ieee80211_swscan_scan_next(struct ieee80211vap *vap)
 489 {
 490         struct ieee80211com *ic = vap->iv_ic;
 491         struct ieee80211_scan_state *ss = ic->ic_scan;
 492
 493         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
 494
 495         /* wake up the scan task */
 496         IEEE80211_LOCK(ic);
 497         scan_signal(ss);
 498         IEEE80211_UNLOCK(ic);
 499 }
 500
 501 /*
 502  * Public access to scan_next for drivers that are not able to scan single
 503  * channels (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;
 510
 511         IEEE80211_LOCK_ASSERT(ic);
 512
 513         ss = ic->ic_scan;
 514         scan_signal(ss);
 515 }
 516
 517 /*
 518  * Probe the curent channel, if allowed, while scanning.
 519  * If the channel is not marked passive-only then send
 520  * a probe request immediately.  Otherwise mark state and
 521  * listen for beacons on the channel; if we receive something
 522  * then we'll transmit a probe request.
 523  */
 524 static void
 525 ieee80211_swscan_probe_curchan(struct ieee80211vap *vap, int force)
 526 {
 527         struct ieee80211com *ic = vap->iv_ic;
 528         struct ieee80211_scan_state *ss = ic->ic_scan;
 529         struct ifnet *ifp = vap->iv_ifp;
 530         int i;
 531
 532         /*
 533          * Send directed probe requests followed by any
 534          * broadcast probe request.
 535          * XXX remove dependence on ic/vap->iv_bss
 536          */
 537         for (i = 0; i < ss->ss_nssid; i++)
 538                 ieee80211_send_probereq(vap->iv_bss,
 539                         vap->iv_myaddr, ifp->if_broadcastaddr,
 540                         ifp->if_broadcastaddr,
 541                         ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
 542         if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
 543                 ieee80211_send_probereq(vap->iv_bss,
 544                         vap->iv_myaddr, ifp->if_broadcastaddr,
 545                         ifp->if_broadcastaddr,
 546                         "", 0);
 547 }
 548
 549 /*
 550  * Scan curchan.  If this is an active scan and the channel
 551  * is not marked passive then send probe request frame(s).
 552  * Arrange for the channel change after maxdwell ticks.
 553  */
 554 static void
 555 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
 556 {
 557         struct ieee80211vap *vap  = ss->ss_vap;
 558
 559         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 560             "%s: calling; maxdwell=%lu\n",
 561             __func__,
 562             maxdwell);
 563         IEEE80211_LOCK(vap->iv_ic);
 564         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 565                 ieee80211_probe_curchan(vap, 0);
 566         taskqueue_enqueue_timeout(vap->iv_ic->ic_tq,
 567             &SCAN_PRIVATE(ss)->ss_scan_curchan, maxdwell);
 568         IEEE80211_UNLOCK(vap->iv_ic);
 569 }
 570
 571 static void
 572 scan_signal(void *arg)
 573 {
 574         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
 575         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 576         struct timeout_task *scan_task = &ss_priv->ss_scan_curchan;
 577         struct ieee80211com *ic = ss->ss_ic;
 578
 579         IEEE80211_LOCK_ASSERT(ic);
 580
 581         if (ss_priv->ss_iflags & ISCAN_RUNNING) {
 582                 if (taskqueue_cancel_timeout(ic->ic_tq, scan_task, NULL) == 0)
 583                         taskqueue_enqueue_timeout(ic->ic_tq, scan_task, 0);
 584         }
 585 }
 586
 587 /*
 588  * Handle mindwell requirements completed; initiate a channel
 589  * change to the next channel asap.
 590  */
 591 static void
 592 scan_mindwell(struct ieee80211_scan_state *ss)
 593 {
 594         struct ieee80211com *ic = ss->ss_ic;
 595
 596         IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
 597
 598         IEEE80211_LOCK(ic);
 599         scan_signal(ss);
 600         IEEE80211_UNLOCK(ic);
 601 }
 602
 603 static void
 604 scan_start(void *arg, int pending)
 605 {
 606 #define ISCAN_REP       (ISCAN_MINDWELL | ISCAN_DISCARD)
 607         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
 608         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 609         struct ieee80211vap *vap = ss->ss_vap;
 610         struct ieee80211com *ic = ss->ss_ic;
 611
 612         IEEE80211_LOCK(ic);
 613         if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
 614             (ss_priv->ss_iflags & ISCAN_ABORT)) {
 615                 /* Cancelled before we started */
 616                 scan_done(ss, 0);
 617                 return;
 618         }
 619
 620         if (ss->ss_next == ss->ss_last) {
 621                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 622                         "%s: no channels to scan\n", __func__);
 623                 scan_done(ss, 1);
 624                 return;
 625         }
 626
 627         if (vap->iv_opmode == IEEE80211_M_STA &&
 628             vap->iv_state == IEEE80211_S_RUN) {
 629                 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
 630                         /* Enable station power save mode */
 631                         vap->iv_sta_ps(vap, 1);
 632                         /*
 633                          * Use an 1ms delay so the null data frame has a chance
 634                          * to go out.
 635                          * XXX Should use M_TXCB mechanism to eliminate this.
 636                          */
 637                         mtx_sleep(vap, IEEE80211_LOCK_OBJ(ic), PCATCH,
 638                             "sta_ps", msecs_to_ticks(1));
 639                         if (ss_priv->ss_iflags & ISCAN_ABORT) {
 640                                 scan_done(ss, 0);
 641                                 return;
 642                         }
 643                 }
 644         }
 645
 646         ss_priv->ss_scanend = ticks + ss_priv->ss_duration;
 647
 648         /* XXX scan state can change! Re-validate scan state! */
 649
 650         IEEE80211_UNLOCK(ic);
 651
 652         ic->ic_scan_start(ic);          /* notify driver */
 653
 654         scan_curchan_task(ss, 0);
 655 }
 656
 657 static void
 658 scan_curchan_task(void *arg, int pending)
 659 {
 660         struct ieee80211_scan_state *ss = arg;
 661         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 662         struct ieee80211vap *vap = ss->ss_vap;
 663         struct ieee80211com *ic = ss->ss_ic;
 664         struct ieee80211_channel *chan;
 665         unsigned long maxdwell;
 666         int scandone;
 667
 668         IEEE80211_LOCK(ic);
 669 end:
 670         scandone = (ss->ss_next >= ss->ss_last) ||
 671             (ss_priv->ss_iflags & ISCAN_CANCEL) != 0;
 672
 673         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 674             "%s: loop start; scandone=%d\n",
 675             __func__,
 676             scandone);
 677
 678         if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
 679             (ss_priv->ss_iflags & ISCAN_ABORT) ||
 680              time_after(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) {
 681                 ss_priv->ss_iflags &= ~ISCAN_RUNNING;
 682                 scan_end(ss, scandone);
 683                 return;
 684         } else
 685                 ss_priv->ss_iflags |= ISCAN_RUNNING;
 686
 687         chan = ss->ss_chans[ss->ss_next++];
 688
 689         /*
 690          * Watch for truncation due to the scan end time.
 691          */
 692         if (time_after(ticks + ss->ss_maxdwell, ss_priv->ss_scanend))
 693                 maxdwell = ss_priv->ss_scanend - ticks;
 694         else
 695                 maxdwell = ss->ss_maxdwell;
 696
 697         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 698             "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
 699             __func__,
 700             ieee80211_chan2ieee(ic, ic->ic_curchan),
 701             ieee80211_channel_type_char(ic->ic_curchan),
 702             ieee80211_chan2ieee(ic, chan),
 703             ieee80211_channel_type_char(chan),
 704             (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
 705                 (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
 706                 "active" : "passive",
 707             ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
 708
 709         /*
 710          * Potentially change channel and phy mode.
 711          */
 712         ic->ic_curchan = chan;
 713         ic->ic_rt = ieee80211_get_ratetable(chan);
 714         IEEE80211_UNLOCK(ic);
 715         /*
 716          * Perform the channel change and scan unlocked so the driver
 717          * may sleep. Once set_channel returns the hardware has
 718          * completed the channel change.
 719          */
 720         ic->ic_set_channel(ic);
 721         ieee80211_radiotap_chan_change(ic);
 722
 723         /*
 724          * Scan curchan.  Drivers for "intelligent hardware"
 725          * override ic_scan_curchan to tell the device to do
 726          * the work.  Otherwise we manage the work ourselves;
 727          * sending a probe request (as needed), and arming the
 728          * timeout to switch channels after maxdwell ticks.
 729          *
 730          * scan_curchan should only pause for the time required to
 731          * prepare/initiate the hardware for the scan (if at all).
 732          */
 733         ic->ic_scan_curchan(ss, maxdwell);
 734         IEEE80211_LOCK(ic);
 735
 736         /* XXX scan state can change! Re-validate scan state! */
 737
 738         ss_priv->ss_chanmindwell = ticks + ss->ss_mindwell;
 739         /* clear mindwell lock and initial channel change flush */
 740         ss_priv->ss_iflags &= ~ISCAN_REP;
 741
 742         if (ss_priv->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT))
 743                 goto end;
 744
 745         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: waiting\n", __func__);
 746         IEEE80211_UNLOCK(ic);
 747 }
 748
 749 static void
 750 scan_end(struct ieee80211_scan_state *ss, int scandone)
 751 {
 752         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 753         struct ieee80211vap *vap = ss->ss_vap;
 754         struct ieee80211com *ic = ss->ss_ic;
 755
 756         IEEE80211_LOCK_ASSERT(ic);
 757
 758         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: out\n", __func__);
 759
 760         if (ss_priv->ss_iflags & ISCAN_ABORT) {
 761                 scan_done(ss, scandone);
 762                 return;
 763         }
 764
 765         IEEE80211_UNLOCK(ic);
 766         ic->ic_scan_end(ic);            /* notify driver */
 767         IEEE80211_LOCK(ic);
 768         /* XXX scan state can change! Re-validate scan state! */
 769
 770         /*
 771          * Since a cancellation may have occured during one of the
 772          * driver calls (whilst unlocked), update scandone.
 773          */
 774         if (scandone == 0 && (ss_priv->ss_iflags & ISCAN_CANCEL) != 0) {
 775                 /* XXX printf? */
 776                 if_printf(vap->iv_ifp,
 777                     "%s: OOPS! scan cancelled during driver call (1)!\n",
 778                     __func__);
 779                 scandone = 1;
 780         }
 781
 782         /*
 783          * Record scan complete time.  Note that we also do
 784          * this when canceled so any background scan will
 785          * not be restarted for a while.
 786          */
 787         if (scandone)
 788                 ic->ic_lastscan = ticks;
 789         /* return to the bss channel */
 790         if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
 791             ic->ic_curchan != ic->ic_bsschan) {
 792                 ieee80211_setupcurchan(ic, ic->ic_bsschan);
 793                 IEEE80211_UNLOCK(ic);
 794                 ic->ic_set_channel(ic);
 795                 ieee80211_radiotap_chan_change(ic);
 796                 IEEE80211_LOCK(ic);
 797         }
 798         /* clear internal flags and any indication of a pick */
 799         ss_priv->ss_iflags &= ~ISCAN_REP;
 800         ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
 801
 802         /*
 803          * If not canceled and scan completed, do post-processing.
 804          * If the callback function returns 0, then it wants to
 805          * continue/restart scanning.  Unfortunately we needed to
 806          * notify the driver to end the scan above to avoid having
 807          * rx frames alter the scan candidate list.
 808          */
 809         if ((ss_priv->ss_iflags & ISCAN_CANCEL) == 0 &&
 810             !ss->ss_ops->scan_end(ss, vap) &&
 811             (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
 812             time_before(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) {
 813                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 814                     "%s: done, restart "
 815                     "[ticks %u, dwell min %lu scanend %lu]\n",
 816                     __func__,
 817                     ticks, ss->ss_mindwell, ss_priv->ss_scanend);
 818                 ss->ss_next = 0;        /* reset to begining */
 819                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 820                         vap->iv_stats.is_scan_active++;
 821                 else
 822                         vap->iv_stats.is_scan_passive++;
 823
 824                 ss->ss_ops->scan_restart(ss, vap);      /* XXX? */
 825                 ieee80211_runtask(ic, &ss_priv->ss_scan_start);
 826                 IEEE80211_UNLOCK(ic);
 827                 return;
 828         }
 829
 830         /* past here, scandone is ``true'' if not in bg mode */
 831         if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
 832                 scandone = 1;
 833
 834         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 835             "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
 836             __func__, scandone ? "done" : "stopped",
 837             ticks, ss->ss_mindwell, ss_priv->ss_scanend);
 838
 839         /*
 840          * Since a cancellation may have occured during one of the
 841          * driver calls (whilst unlocked), update scandone.
 842          */
 843         if (scandone == 0 && (ss_priv->ss_iflags & ISCAN_CANCEL) != 0) {
 844                 /* XXX printf? */
 845                 if_printf(vap->iv_ifp,
 846                     "%s: OOPS! scan cancelled during driver call (2)!\n",
 847                     __func__);
 848                 scandone = 1;
 849         }
 850
 851         scan_done(ss, scandone);
 852 }
 853
 854 static void
 855 scan_done(struct ieee80211_scan_state *ss, int scandone)
 856 {
 857         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 858         struct ieee80211com *ic = ss->ss_ic;
 859         struct ieee80211vap *vap = ss->ss_vap;
 860
 861         IEEE80211_LOCK_ASSERT(ic);
 862
 863         /*
 864          * Clear the SCAN bit first in case frames are
 865          * pending on the station power save queue.  If
 866          * we defer this then the dispatch of the frames
 867          * may generate a request to cancel scanning.
 868          */
 869         ic->ic_flags &= ~IEEE80211_F_SCAN;
 870
 871         /*
 872          * Drop out of power save mode when a scan has
 873          * completed.  If this scan was prematurely terminated
 874          * because it is a background scan then don't notify
 875          * the ap; we'll either return to scanning after we
 876          * receive the beacon frame or we'll drop out of power
 877          * save mode because the beacon indicates we have frames
 878          * waiting for us.
 879          */
 880         if (scandone) {
 881                 vap->iv_sta_ps(vap, 0);
 882                 if (ss->ss_next >= ss->ss_last) {
 883                         ieee80211_notify_scan_done(vap);
 884                         ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
 885                 }
 886         }
 887         ss_priv->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
 888         ss_priv->ss_scanend = 0;
 889         ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
 890         IEEE80211_UNLOCK(ic);
 891 #undef ISCAN_REP
 892 }
 893
 894 /*
 895  * Process a beacon or probe response frame.
 896  */
 897 static void
 898 ieee80211_swscan_add_scan(struct ieee80211vap *vap,
 899         struct ieee80211_channel *curchan,
 900         const struct ieee80211_scanparams *sp,
 901         const struct ieee80211_frame *wh,
 902         int subtype, int rssi, int noise)
 903 {
 904         struct ieee80211com *ic = vap->iv_ic;
 905         struct ieee80211_scan_state *ss = ic->ic_scan;
 906
 907         /* XXX locking */
 908         /*
 909          * Frames received during startup are discarded to avoid
 910          * using scan state setup on the initial entry to the timer
 911          * callback.  This can occur because the device may enable
 912          * rx prior to our doing the initial channel change in the
 913          * timer routine.
 914          */
 915         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
 916                 return;
 917 #ifdef IEEE80211_DEBUG
 918         if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
 919                 ieee80211_scan_dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
 920 #endif
 921         if (ss->ss_ops != NULL &&
 922             ss->ss_ops->scan_add(ss, curchan, sp, wh, subtype, rssi, noise)) {
 923                 /*
 924                  * If we've reached the min dwell time terminate
 925                  * the timer so we'll switch to the next channel.
 926                  */
 927                 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
 928                     time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
 929                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 930                             "%s: chan %3d%c min dwell met (%u > %lu)\n",
 931                             __func__,
 932                             ieee80211_chan2ieee(ic, ic->ic_curchan),
 933                             ieee80211_channel_type_char(ic->ic_curchan),
 934                             ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
 935                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
 936                         /*
 937                          * NB: trigger at next clock tick or wait for the
 938                          * hardware.
 939                          */
 940                         ic->ic_scan_mindwell(ss);
 941                 }
 942         }
 943 }
 944
 945 static struct ieee80211_scan_methods swscan_methods = {
 946         .sc_attach = ieee80211_swscan_attach,
 947         .sc_detach = ieee80211_swscan_detach,
 948         .sc_vattach = ieee80211_swscan_vattach,
 949         .sc_vdetach = ieee80211_swscan_vdetach,
 950         .sc_set_scan_duration = ieee80211_swscan_set_scan_duration,
 951         .sc_start_scan = ieee80211_swscan_start_scan,
 952         .sc_check_scan = ieee80211_swscan_check_scan,
 953         .sc_bg_scan = ieee80211_swscan_bg_scan,
 954         .sc_cancel_scan = ieee80211_swscan_cancel_scan,
 955         .sc_cancel_anyscan = ieee80211_swscan_cancel_anyscan,
 956         .sc_scan_next = ieee80211_swscan_scan_next,
 957         .sc_scan_done = ieee80211_swscan_scan_done,
 958         .sc_scan_probe_curchan = ieee80211_swscan_probe_curchan,
 959         .sc_add_scan = ieee80211_swscan_add_scan
 960 };
 961
 962 /*
 963  * Default scan attach method.
 964  */
 965 void
 966 ieee80211_swscan_attach(struct ieee80211com *ic)
 967 {
 968         struct scan_state *ss;
 969
 970         /*
 971          * Setup the default methods
 972          */
 973         ic->ic_scan_methods = &swscan_methods;
 974
 975         /* Allocate initial scan state */
 976         ss = (struct scan_state *) IEEE80211_MALLOC(sizeof(struct scan_state),
 977                 M_80211_SCAN, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
 978         if (ss == NULL) {
 979                 ic->ic_scan = NULL;
 980                 return;
 981         }
 982         TASK_INIT(&ss->ss_scan_start, 0, scan_start, ss);
 983         TIMEOUT_TASK_INIT(ic->ic_tq, &ss->ss_scan_curchan, 0,
 984             scan_curchan_task, ss);
 985
 986         ic->ic_scan = &ss->base;
 987         ss->base.ss_ic = ic;
 988
 989         ic->ic_scan_curchan = scan_curchan;
 990         ic->ic_scan_mindwell = scan_mindwell;
 991 }