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/condvar.h>
  39
  40 #include <sys/socket.h>
  41
  42 #include <net/if.h>
  43 #include <net/if_var.h>
  44 #include <net/if_media.h>
  45 #include <net/ethernet.h>
  46
  47 #include <net80211/ieee80211_var.h>
  48
  49 #include <net80211/ieee80211_scan_sw.h>
  50
  51 #include <net/bpf.h>
  52
  53 struct scan_state {
  54         struct ieee80211_scan_state base;       /* public state */
  55
  56         u_int           ss_iflags;              /* flags used internally */
  57 #define ISCAN_MINDWELL  0x0001          /* min dwell time reached */
  58 #define ISCAN_DISCARD   0x0002          /* discard rx'd frames */
  59 #define ISCAN_CANCEL    0x0004          /* cancel current scan */
  60 #define ISCAN_ABORT     0x0008          /* end the scan immediately */
  61         unsigned long   ss_chanmindwell;        /* min dwell on curchan */
  62         unsigned long   ss_scanend;             /* time scan must stop */
  63         u_int           ss_duration;            /* duration for next scan */
  64         struct task     ss_scan_task;           /* scan execution */
  65         struct cv       ss_scan_cv;             /* scan signal */
  66         struct callout  ss_scan_timer;          /* scan timer */
  67 };
  68 #define SCAN_PRIVATE(ss)        ((struct scan_state *) ss)
  69
  70 /*
  71  * Amount of time to go off-channel during a background
  72  * scan.  This value should be large enough to catch most
  73  * ap's but short enough that we can return on-channel
  74  * before our listen interval expires.
  75  *
  76  * XXX tunable
  77  * XXX check against configured listen interval
  78  */
  79 #define IEEE80211_SCAN_OFFCHANNEL       msecs_to_ticks(150)
  80
  81 /*
  82  * Roaming-related defaults.  RSSI thresholds are as returned by the
  83  * driver (.5dBm).  Transmit rate thresholds are IEEE rate codes (i.e
  84  * .5M units) or MCS.
  85  */
  86 /* rssi thresholds */
  87 #define ROAM_RSSI_11A_DEFAULT           14      /* 11a bss */
  88 #define ROAM_RSSI_11B_DEFAULT           14      /* 11b bss */
  89 #define ROAM_RSSI_11BONLY_DEFAULT       14      /* 11b-only bss */
  90 /* transmit rate thresholds */
  91 #define ROAM_RATE_11A_DEFAULT           2*12    /* 11a bss */
  92 #define ROAM_RATE_11B_DEFAULT           2*5     /* 11b bss */
  93 #define ROAM_RATE_11BONLY_DEFAULT       2*1     /* 11b-only bss */
  94 #define ROAM_RATE_HALF_DEFAULT          2*6     /* half-width 11a/g bss */
  95 #define ROAM_RATE_QUARTER_DEFAULT       2*3     /* quarter-width 11a/g bss */
  96 #define ROAM_MCS_11N_DEFAULT            (1 | IEEE80211_RATE_MCS) /* 11n bss */
  97
  98 static  void scan_curchan(struct ieee80211_scan_state *, unsigned long);
  99 static  void scan_mindwell(struct ieee80211_scan_state *);
 100 static  void scan_signal(void *);
 101 static  void scan_task(void *, int);
 102
 103 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
 104
 105 void
 106 ieee80211_swscan_attach(struct ieee80211com *ic)
 107 {
 108         struct scan_state *ss;
 109
 110         ss = (struct scan_state *) malloc(sizeof(struct scan_state),
 111                 M_80211_SCAN, M_NOWAIT | M_ZERO);
 112         if (ss == NULL) {
 113                 ic->ic_scan = NULL;
 114                 return;
 115         }
 116         callout_init_mtx(&ss->ss_scan_timer, IEEE80211_LOCK_OBJ(ic), 0);
 117         cv_init(&ss->ss_scan_cv, "scan");
 118         TASK_INIT(&ss->ss_scan_task, 0, scan_task, ss);
 119
 120         ic->ic_scan = &ss->base;
 121         ss->base.ss_ic = ic;
 122
 123         ic->ic_scan_curchan = scan_curchan;
 124         ic->ic_scan_mindwell = scan_mindwell;
 125
 126         /*
 127          * TODO: all of the non-vap scan calls should be methods!
 128          */
 129 }
 130
 131 void
 132 ieee80211_swscan_detach(struct ieee80211com *ic)
 133 {
 134         struct ieee80211_scan_state *ss = ic->ic_scan;
 135
 136         if (ss != NULL) {
 137                 IEEE80211_LOCK(ic);
 138                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
 139                 scan_signal(ss);
 140                 IEEE80211_UNLOCK(ic);
 141                 ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 142                 callout_drain(&SCAN_PRIVATE(ss)->ss_scan_timer);
 143                 KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0,
 144                     ("scan still running"));
 145
 146                 /*
 147                  * For now, do the ss_ops detach here rather
 148                  * than ieee80211_scan_detach().
 149                  *
 150                  * I'll figure out how to cleanly split things up
 151                  * at a later date.
 152                  */
 153                 if (ss->ss_ops != NULL) {
 154                         ss->ss_ops->scan_detach(ss);
 155                         ss->ss_ops = NULL;
 156                 }
 157                 ic->ic_scan = NULL;
 158                 free(SCAN_PRIVATE(ss), M_80211_SCAN);
 159         }
 160 }
 161
 162 void
 163 ieee80211_swscan_vattach(struct ieee80211vap *vap)
 164 {
 165         /* nothing to do for now */
 166         /*
 167          * TODO: all of the vap scan calls should be methods!
 168          */
 169
 170 }
 171
 172 void
 173 ieee80211_swscan_vdetach(struct ieee80211vap *vap)
 174 {
 175         struct ieee80211com *ic = vap->iv_ic;
 176         struct ieee80211_scan_state *ss;
 177
 178         IEEE80211_LOCK_ASSERT(ic);
 179         ss = ic->ic_scan;
 180         if (ss != NULL && ss->ss_vap == vap) {
 181                 if (ic->ic_flags & IEEE80211_F_SCAN) {
 182                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
 183                         scan_signal(ss);
 184                 }
 185         }
 186 }
 187
 188 void
 189 ieee80211_swscan_set_scan_duration(struct ieee80211vap *vap, u_int duration)
 190 {
 191         struct ieee80211com *ic = vap->iv_ic;
 192         struct ieee80211_scan_state *ss = ic->ic_scan;
 193
 194         IEEE80211_LOCK_ASSERT(ic);
 195
 196         /* NB: flush frames rx'd before 1st channel change */
 197         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
 198         SCAN_PRIVATE(ss)->ss_duration = duration;
 199 }
 200
 201 void
 202 ieee80211_swscan_run_scan_task(struct ieee80211vap *vap)
 203 {
 204         struct ieee80211com *ic = vap->iv_ic;
 205         struct ieee80211_scan_state *ss = ic->ic_scan;
 206
 207         IEEE80211_LOCK_ASSERT(ic);
 208
 209         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 210 }
 211
 212 /*
 213  * Start a scan unless one is already going.
 214  */
 215 static int
 216 ieee80211_swscan_start_scan_locked(const struct ieee80211_scanner *scan,
 217         struct ieee80211vap *vap, int flags, u_int duration,
 218         u_int mindwell, u_int maxdwell,
 219         u_int nssid, const struct ieee80211_scan_ssid ssids[])
 220 {
 221         struct ieee80211com *ic = vap->iv_ic;
 222         struct ieee80211_scan_state *ss = ic->ic_scan;
 223
 224         IEEE80211_LOCK_ASSERT(ic);
 225
 226         if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
 227                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 228                     "%s: scan inhibited by pending channel change\n", __func__);
 229         } else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
 230                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 231                     "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
 232                     , __func__
 233                     , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
 234                     , duration, mindwell, maxdwell
 235                     , ieee80211_phymode_name[vap->iv_des_mode]
 236                     , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
 237                     , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
 238                     , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
 239                     , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
 240                     , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
 241                     , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
 242                 );
 243
 244                 ieee80211_scan_update_locked(vap, scan);
 245                 if (ss->ss_ops != NULL) {
 246                         if ((flags & IEEE80211_SCAN_NOSSID) == 0)
 247                                 ieee80211_scan_copy_ssid(vap, ss, nssid, ssids);
 248
 249                         /* NB: top 4 bits for internal use */
 250                         ss->ss_flags = flags & 0xfff;
 251                         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 252                                 vap->iv_stats.is_scan_active++;
 253                         else
 254                                 vap->iv_stats.is_scan_passive++;
 255                         if (flags & IEEE80211_SCAN_FLUSH)
 256                                 ss->ss_ops->scan_flush(ss);
 257                         if (flags & IEEE80211_SCAN_BGSCAN)
 258                                 ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
 259
 260                         /* Set duration for this particular scan */
 261                         ieee80211_swscan_set_scan_duration(vap, duration);
 262
 263                         ss->ss_next = 0;
 264                         ss->ss_mindwell = mindwell;
 265                         ss->ss_maxdwell = maxdwell;
 266                         /* NB: scan_start must be before the scan runtask */
 267                         ss->ss_ops->scan_start(ss, vap);
 268 #ifdef IEEE80211_DEBUG
 269                         if (ieee80211_msg_scan(vap))
 270                                 ieee80211_scan_dump(ss);
 271 #endif /* IEEE80211_DEBUG */
 272                         ic->ic_flags |= IEEE80211_F_SCAN;
 273
 274                         /* Start scan task */
 275                         ieee80211_swscan_run_scan_task(vap);
 276                 }
 277                 return 1;
 278         } else {
 279                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 280                     "%s: %s scan already in progress\n", __func__,
 281                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
 282         }
 283         return 0;
 284 }
 285
 286
 287 /*
 288  * Start a scan unless one is already going.
 289  *
 290  * Called without the comlock held; grab the comlock as appropriate.
 291  */
 292 int
 293 ieee80211_swscan_start_scan(const struct ieee80211_scanner *scan,
 294     struct ieee80211vap *vap, int flags,
 295     u_int duration, u_int mindwell, u_int maxdwell,
 296     u_int nssid, const struct ieee80211_scan_ssid ssids[])
 297 {
 298         struct ieee80211com *ic = vap->iv_ic;
 299         int result;
 300
 301         IEEE80211_UNLOCK_ASSERT(ic);
 302
 303         IEEE80211_LOCK(ic);
 304         result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration,
 305             mindwell, maxdwell, nssid, ssids);
 306         IEEE80211_UNLOCK(ic);
 307
 308         return result;
 309 }
 310
 311 /*
 312  * Check the scan cache for an ap/channel to use; if that
 313  * fails then kick off a new scan.
 314  *
 315  * Called with the comlock held.
 316  *
 317  * XXX TODO: split out!
 318  */
 319 int
 320 ieee80211_swscan_check_scan(const struct ieee80211_scanner *scan,
 321     struct ieee80211vap *vap, int flags,
 322     u_int duration, u_int mindwell, u_int maxdwell,
 323     u_int nssid, const struct ieee80211_scan_ssid ssids[])
 324 {
 325         struct ieee80211com *ic = vap->iv_ic;
 326         struct ieee80211_scan_state *ss = ic->ic_scan;
 327         int result;
 328
 329         IEEE80211_LOCK_ASSERT(ic);
 330
 331         if (ss->ss_ops != NULL) {
 332                 /* XXX verify ss_ops matches vap->iv_opmode */
 333                 if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
 334                         /*
 335                          * Update the ssid list and mark flags so if
 336                          * we call start_scan it doesn't duplicate work.
 337                          */
 338                         ieee80211_scan_copy_ssid(vap, ss, nssid, ssids);
 339                         flags |= IEEE80211_SCAN_NOSSID;
 340                 }
 341                 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
 342                     (flags & IEEE80211_SCAN_FLUSH) == 0 &&
 343                     time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
 344                         /*
 345                          * We're not currently scanning and the cache is
 346                          * deemed hot enough to consult.  Lock out others
 347                          * by marking IEEE80211_F_SCAN while we decide if
 348                          * something is already in the scan cache we can
 349                          * use.  Also discard any frames that might come
 350                          * in while temporarily marked as scanning.
 351                          */
 352                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
 353                         ic->ic_flags |= IEEE80211_F_SCAN;
 354
 355                         /* NB: need to use supplied flags in check */
 356                         ss->ss_flags = flags & 0xff;
 357                         result = ss->ss_ops->scan_end(ss, vap);
 358
 359                         ic->ic_flags &= ~IEEE80211_F_SCAN;
 360                         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
 361                         if (result) {
 362                                 ieee80211_notify_scan_done(vap);
 363                                 return 1;
 364                         }
 365                 }
 366         }
 367         result = ieee80211_swscan_start_scan_locked(scan, vap, flags, duration,
 368             mindwell, maxdwell, nssid, ssids);
 369
 370         return result;
 371 }
 372
 373 /*
 374  * Restart a previous scan.  If the previous scan completed
 375  * then we start again using the existing channel list.
 376  */
 377 int
 378 ieee80211_swscan_bg_scan(const struct ieee80211_scanner *scan,
 379     struct ieee80211vap *vap, int flags)
 380 {
 381         struct ieee80211com *ic = vap->iv_ic;
 382         struct ieee80211_scan_state *ss = ic->ic_scan;
 383
 384         /* XXX assert unlocked? */
 385         // IEEE80211_UNLOCK_ASSERT(ic);
 386
 387         IEEE80211_LOCK(ic);
 388         if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
 389                 u_int duration;
 390                 /*
 391                  * Go off-channel for a fixed interval that is large
 392                  * enough to catch most ap's but short enough that
 393                  * we can return on-channel before our listen interval
 394                  * expires.
 395                  */
 396                 duration = IEEE80211_SCAN_OFFCHANNEL;
 397
 398                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 399                     "%s: %s scan, ticks %u duration %lu\n", __func__,
 400                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
 401                     ticks, duration);
 402
 403                 ieee80211_scan_update_locked(vap, scan);
 404                 if (ss->ss_ops != NULL) {
 405                         ss->ss_vap = vap;
 406                         /*
 407                          * A background scan does not select a new sta; it
 408                          * just refreshes the scan cache.  Also, indicate
 409                          * the scan logic should follow the beacon schedule:
 410                          * we go off-channel and scan for a while, then
 411                          * return to the bss channel to receive a beacon,
 412                          * then go off-channel again.  All during this time
 413                          * we notify the ap we're in power save mode.  When
 414                          * the scan is complete we leave power save mode.
 415                          * If any beacon indicates there are frames pending
 416                          * for us then we drop out of power save mode
 417                          * (and background scan) automatically by way of the
 418                          * usual sta power save logic.
 419                          */
 420                         ss->ss_flags |= IEEE80211_SCAN_NOPICK
 421                                      |  IEEE80211_SCAN_BGSCAN
 422                                      |  flags
 423                                      ;
 424                         /* if previous scan completed, restart */
 425                         if (ss->ss_next >= ss->ss_last) {
 426                                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 427                                         vap->iv_stats.is_scan_active++;
 428                                 else
 429                                         vap->iv_stats.is_scan_passive++;
 430                                 /*
 431                                  * NB: beware of the scan cache being flushed;
 432                                  *     if the channel list is empty use the
 433                                  *     scan_start method to populate it.
 434                                  */
 435                                 ss->ss_next = 0;
 436                                 if (ss->ss_last != 0)
 437                                         ss->ss_ops->scan_restart(ss, vap);
 438                                 else {
 439                                         ss->ss_ops->scan_start(ss, vap);
 440 #ifdef IEEE80211_DEBUG
 441                                         if (ieee80211_msg_scan(vap))
 442                                                 ieee80211_scan_dump(ss);
 443 #endif /* IEEE80211_DEBUG */
 444                                 }
 445                         }
 446                         ieee80211_swscan_set_scan_duration(vap, duration);
 447                         ss->ss_maxdwell = duration;
 448                         ic->ic_flags |= IEEE80211_F_SCAN;
 449                         ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
 450                         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 451                 } else {
 452                         /* XXX msg+stat */
 453                 }
 454         } else {
 455                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 456                     "%s: %s scan already in progress\n", __func__,
 457                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
 458         }
 459         IEEE80211_UNLOCK(ic);
 460
 461         /* NB: racey, does it matter? */
 462         return (ic->ic_flags & IEEE80211_F_SCAN);
 463 }
 464
 465 /*
 466  * Cancel any scan currently going on for the specified vap.
 467  */
 468 void
 469 ieee80211_swscan_cancel_scan(struct ieee80211vap *vap)
 470 {
 471         struct ieee80211com *ic = vap->iv_ic;
 472         struct ieee80211_scan_state *ss = ic->ic_scan;
 473
 474         IEEE80211_LOCK(ic);
 475         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
 476             ss->ss_vap == vap &&
 477             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
 478                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 479                     "%s: cancel %s scan\n", __func__,
 480                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
 481                         "active" : "passive");
 482
 483                 /* clear bg scan NOPICK and mark cancel request */
 484                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
 485                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
 486                 /* wake up the scan task */
 487                 scan_signal(ss);
 488         } else {
 489                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 490                     "%s: called; F_SCAN=%d, vap=%s, CANCEL=%d\n",
 491                         __func__,
 492                         !! (ic->ic_flags & IEEE80211_F_SCAN),
 493                         (ss->ss_vap == vap ? "match" : "nomatch"),
 494                         !! (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL));
 495         }
 496         IEEE80211_UNLOCK(ic);
 497 }
 498
 499 /*
 500  * Cancel any scan currently going on.
 501  */
 502 void
 503 ieee80211_swscan_cancel_anyscan(struct ieee80211vap *vap)
 504 {
 505         struct ieee80211com *ic = vap->iv_ic;
 506         struct ieee80211_scan_state *ss = ic->ic_scan;
 507
 508         IEEE80211_LOCK(ic);
 509         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
 510             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
 511                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 512                     "%s: cancel %s scan\n", __func__,
 513                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
 514                         "active" : "passive");
 515
 516                 /* clear bg scan NOPICK and mark cancel request */
 517                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
 518                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
 519                 /* wake up the scan task */
 520                 scan_signal(ss);
 521         } else {
 522                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 523                     "%s: called; F_SCAN=%d, vap=%s, CANCEL=%d\n",
 524                         __func__,
 525                         !! (ic->ic_flags & IEEE80211_F_SCAN),
 526                         (ss->ss_vap == vap ? "match" : "nomatch"),
 527                         !! (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL));
 528         }
 529         IEEE80211_UNLOCK(ic);
 530 }
 531
 532 /*
 533  * Public access to scan_next for drivers that manage
 534  * scanning themselves (e.g. for firmware-based devices).
 535  */
 536 void
 537 ieee80211_swscan_scan_next(struct ieee80211vap *vap)
 538 {
 539         struct ieee80211com *ic = vap->iv_ic;
 540         struct ieee80211_scan_state *ss = ic->ic_scan;
 541
 542         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
 543
 544         /* wake up the scan task */
 545         IEEE80211_LOCK(ic);
 546         scan_signal(ss);
 547         IEEE80211_UNLOCK(ic);
 548 }
 549
 550 /*
 551  * Public access to scan_next for drivers that are not able to scan single
 552  * channels (e.g. for firmware-based devices).
 553  */
 554 void
 555 ieee80211_swscan_scan_done(struct ieee80211vap *vap)
 556 {
 557         struct ieee80211com *ic = vap->iv_ic;
 558         struct ieee80211_scan_state *ss;
 559
 560         IEEE80211_LOCK_ASSERT(ic);
 561
 562         ss = ic->ic_scan;
 563         scan_signal(ss);
 564 }
 565
 566 /*
 567  * Probe the curent channel, if allowed, while scanning.
 568  * If the channel is not marked passive-only then send
 569  * a probe request immediately.  Otherwise mark state and
 570  * listen for beacons on the channel; if we receive something
 571  * then we'll transmit a probe request.
 572  */
 573 void
 574 ieee80211_swscan_probe_curchan(struct ieee80211vap *vap, int force)
 575 {
 576         struct ieee80211com *ic = vap->iv_ic;
 577         struct ieee80211_scan_state *ss = ic->ic_scan;
 578         struct ifnet *ifp = vap->iv_ifp;
 579         int i;
 580
 581         /*
 582          * Send directed probe requests followed by any
 583          * broadcast probe request.
 584          * XXX remove dependence on ic/vap->iv_bss
 585          */
 586         for (i = 0; i < ss->ss_nssid; i++)
 587                 ieee80211_send_probereq(vap->iv_bss,
 588                         vap->iv_myaddr, ifp->if_broadcastaddr,
 589                         ifp->if_broadcastaddr,
 590                         ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
 591         if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
 592                 ieee80211_send_probereq(vap->iv_bss,
 593                         vap->iv_myaddr, ifp->if_broadcastaddr,
 594                         ifp->if_broadcastaddr,
 595                         "", 0);
 596 }
 597
 598 /*
 599  * Scan curchan.  If this is an active scan and the channel
 600  * is not marked passive then send probe request frame(s).
 601  * Arrange for the channel change after maxdwell ticks.
 602  */
 603 static void
 604 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
 605 {
 606         struct ieee80211vap *vap  = ss->ss_vap;
 607
 608         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 609             "%s: calling; maxdwell=%lu\n",
 610             __func__,
 611             maxdwell);
 612         IEEE80211_LOCK(vap->iv_ic);
 613         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 614                 ieee80211_probe_curchan(vap, 0);
 615         callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
 616             maxdwell, scan_signal, ss);
 617         IEEE80211_UNLOCK(vap->iv_ic);
 618 }
 619
 620 static void
 621 scan_signal(void *arg)
 622 {
 623         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
 624
 625         IEEE80211_LOCK_ASSERT(ss->ss_ic);
 626         cv_signal(&SCAN_PRIVATE(ss)->ss_scan_cv);
 627 }
 628
 629 /*
 630  * Handle mindwell requirements completed; initiate a channel
 631  * change to the next channel asap.
 632  */
 633 static void
 634 scan_mindwell(struct ieee80211_scan_state *ss)
 635 {
 636         struct ieee80211com *ic = ss->ss_ic;
 637
 638         IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
 639
 640         IEEE80211_LOCK(ic);
 641         scan_signal(ss);
 642         IEEE80211_UNLOCK(ic);
 643 }
 644
 645 static void
 646 scan_task(void *arg, int pending)
 647 {
 648 #define ISCAN_REP       (ISCAN_MINDWELL | ISCAN_DISCARD)
 649         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
 650         struct ieee80211vap *vap = ss->ss_vap;
 651         struct ieee80211com *ic = ss->ss_ic;
 652         struct ieee80211_channel *chan;
 653         unsigned long maxdwell, scanend;
 654         int scandone = 0;
 655
 656         IEEE80211_LOCK(ic);
 657         if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
 658             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
 659                 /* Cancelled before we started */
 660                 goto done;
 661         }
 662
 663         if (ss->ss_next == ss->ss_last) {
 664                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 665                         "%s: no channels to scan\n", __func__);
 666                 scandone = 1;
 667                 goto done;
 668         }
 669
 670         if (vap->iv_opmode == IEEE80211_M_STA &&
 671             vap->iv_state == IEEE80211_S_RUN) {
 672                 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
 673                         /* Enable station power save mode */
 674                         vap->iv_sta_ps(vap, 1);
 675                         /*
 676                          * Use an 1ms delay so the null data frame has a chance
 677                          * to go out.
 678                          * XXX Should use M_TXCB mechanism to eliminate this.
 679                          */
 680                         cv_timedwait(&SCAN_PRIVATE(ss)->ss_scan_cv,
 681                             IEEE80211_LOCK_OBJ(ic), hz / 1000);
 682                         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
 683                                 goto done;
 684                 }
 685         }
 686
 687         scanend = ticks + SCAN_PRIVATE(ss)->ss_duration;
 688
 689         /* XXX scan state can change! Re-validate scan state! */
 690
 691         IEEE80211_UNLOCK(ic);
 692         ic->ic_scan_start(ic);          /* notify driver */
 693         IEEE80211_LOCK(ic);
 694
 695         for (;;) {
 696
 697                 scandone = (ss->ss_next >= ss->ss_last) ||
 698                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0;
 699
 700                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 701                     "%s: loop start; scandone=%d\n",
 702                     __func__,
 703                     scandone);
 704
 705                 if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
 706                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT) ||
 707                      time_after(ticks + ss->ss_mindwell, scanend))
 708                         break;
 709
 710                 chan = ss->ss_chans[ss->ss_next++];
 711
 712                 /*
 713                  * Watch for truncation due to the scan end time.
 714                  */
 715                 if (time_after(ticks + ss->ss_maxdwell, scanend))
 716                         maxdwell = scanend - ticks;
 717                 else
 718                         maxdwell = ss->ss_maxdwell;
 719
 720                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 721                     "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
 722                     __func__,
 723                     ieee80211_chan2ieee(ic, ic->ic_curchan),
 724                     ieee80211_channel_type_char(ic->ic_curchan),
 725                     ieee80211_chan2ieee(ic, chan),
 726                     ieee80211_channel_type_char(chan),
 727                     (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
 728                         (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
 729                         "active" : "passive",
 730                     ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
 731
 732                 /*
 733                  * Potentially change channel and phy mode.
 734                  */
 735                 ic->ic_curchan = chan;
 736                 ic->ic_rt = ieee80211_get_ratetable(chan);
 737                 IEEE80211_UNLOCK(ic);
 738                 /*
 739                  * Perform the channel change and scan unlocked so the driver
 740                  * may sleep. Once set_channel returns the hardware has
 741                  * completed the channel change.
 742                  */
 743                 ic->ic_set_channel(ic);
 744                 ieee80211_radiotap_chan_change(ic);
 745
 746                 /*
 747                  * Scan curchan.  Drivers for "intelligent hardware"
 748                  * override ic_scan_curchan to tell the device to do
 749                  * the work.  Otherwise we manage the work outselves;
 750                  * sending a probe request (as needed), and arming the
 751                  * timeout to switch channels after maxdwell ticks.
 752                  *
 753                  * scan_curchan should only pause for the time required to
 754                  * prepare/initiate the hardware for the scan (if at all), the
 755                  * below condvar is used to sleep for the channels dwell time
 756                  * and allows it to be signalled for abort.
 757                  */
 758                 ic->ic_scan_curchan(ss, maxdwell);
 759                 IEEE80211_LOCK(ic);
 760
 761                 /* XXX scan state can change! Re-validate scan state! */
 762
 763                 SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell;
 764                 /* clear mindwell lock and initial channel change flush */
 765                 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
 766
 767                 if ((SCAN_PRIVATE(ss)->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)))
 768                         continue;
 769
 770                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: waiting\n", __func__);
 771                 /* Wait to be signalled to scan the next channel */
 772                 cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv, IEEE80211_LOCK_OBJ(ic));
 773         }
 774
 775         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: out\n", __func__);
 776
 777         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
 778                 goto done;
 779
 780         IEEE80211_UNLOCK(ic);
 781         ic->ic_scan_end(ic);            /* notify driver */
 782         IEEE80211_LOCK(ic);
 783         /* XXX scan state can change! Re-validate scan state! */
 784
 785         /*
 786          * Since a cancellation may have occured during one of the
 787          * driver calls (whilst unlocked), update scandone.
 788          */
 789         if (scandone == 0 &&
 790             ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0)) {
 791                 /* XXX printf? */
 792                 if_printf(vap->iv_ifp,
 793                     "%s: OOPS! scan cancelled during driver call (1)!\n",
 794                     __func__);
 795                 scandone = 1;
 796         }
 797
 798         /*
 799          * Record scan complete time.  Note that we also do
 800          * this when canceled so any background scan will
 801          * not be restarted for a while.
 802          */
 803         if (scandone)
 804                 ic->ic_lastscan = ticks;
 805         /* return to the bss channel */
 806         if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
 807             ic->ic_curchan != ic->ic_bsschan) {
 808                 ieee80211_setupcurchan(ic, ic->ic_bsschan);
 809                 IEEE80211_UNLOCK(ic);
 810                 ic->ic_set_channel(ic);
 811                 ieee80211_radiotap_chan_change(ic);
 812                 IEEE80211_LOCK(ic);
 813         }
 814         /* clear internal flags and any indication of a pick */
 815         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
 816         ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
 817
 818         /*
 819          * If not canceled and scan completed, do post-processing.
 820          * If the callback function returns 0, then it wants to
 821          * continue/restart scanning.  Unfortunately we needed to
 822          * notify the driver to end the scan above to avoid having
 823          * rx frames alter the scan candidate list.
 824          */
 825         if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 &&
 826             !ss->ss_ops->scan_end(ss, vap) &&
 827             (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
 828             time_before(ticks + ss->ss_mindwell, scanend)) {
 829                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 830                     "%s: done, restart "
 831                     "[ticks %u, dwell min %lu scanend %lu]\n",
 832                     __func__,
 833                     ticks, ss->ss_mindwell, scanend);
 834                 ss->ss_next = 0;        /* reset to begining */
 835                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 836                         vap->iv_stats.is_scan_active++;
 837                 else
 838                         vap->iv_stats.is_scan_passive++;
 839
 840                 ss->ss_ops->scan_restart(ss, vap);      /* XXX? */
 841                 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 842                 IEEE80211_UNLOCK(ic);
 843                 return;
 844         }
 845
 846         /* past here, scandone is ``true'' if not in bg mode */
 847         if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
 848                 scandone = 1;
 849
 850         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 851             "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
 852             __func__, scandone ? "done" : "stopped",
 853             ticks, ss->ss_mindwell, scanend);
 854
 855         /*
 856          * Since a cancellation may have occured during one of the
 857          * driver calls (whilst unlocked), update scandone.
 858          */
 859         if (scandone == 0 &&
 860             ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0)) {
 861                 /* XXX printf? */
 862                 if_printf(vap->iv_ifp,
 863                     "%s: OOPS! scan cancelled during driver call (2)!\n",
 864                     __func__);
 865                 scandone = 1;
 866         }
 867
 868         /*
 869          * Clear the SCAN bit first in case frames are
 870          * pending on the station power save queue.  If
 871          * we defer this then the dispatch of the frames
 872          * may generate a request to cancel scanning.
 873          */
 874 done:
 875         ic->ic_flags &= ~IEEE80211_F_SCAN;
 876         /*
 877          * Drop out of power save mode when a scan has
 878          * completed.  If this scan was prematurely terminated
 879          * because it is a background scan then don't notify
 880          * the ap; we'll either return to scanning after we
 881          * receive the beacon frame or we'll drop out of power
 882          * save mode because the beacon indicates we have frames
 883          * waiting for us.
 884          */
 885         if (scandone) {
 886                 vap->iv_sta_ps(vap, 0);
 887                 if (ss->ss_next >= ss->ss_last) {
 888                         ieee80211_notify_scan_done(vap);
 889                         ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
 890                 }
 891         }
 892         SCAN_PRIVATE(ss)->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
 893         ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
 894         IEEE80211_UNLOCK(ic);
 895 #undef ISCAN_REP
 896 }
 897
 898 /*
 899  * Process a beacon or probe response frame.
 900  */
 901 void
 902 ieee80211_swscan_add_scan(struct ieee80211vap *vap,
 903         struct ieee80211_channel *curchan,
 904         const struct ieee80211_scanparams *sp,
 905         const struct ieee80211_frame *wh,
 906         int subtype, int rssi, int noise)
 907 {
 908         struct ieee80211com *ic = vap->iv_ic;
 909         struct ieee80211_scan_state *ss = ic->ic_scan;
 910
 911         /* XXX locking */
 912         /*
 913          * Frames received during startup are discarded to avoid
 914          * using scan state setup on the initial entry to the timer
 915          * callback.  This can occur because the device may enable
 916          * rx prior to our doing the initial channel change in the
 917          * timer routine.
 918          */
 919         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
 920                 return;
 921 #ifdef IEEE80211_DEBUG
 922         if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
 923                 ieee80211_scan_dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
 924 #endif
 925         if (ss->ss_ops != NULL &&
 926             ss->ss_ops->scan_add(ss, curchan, sp, wh, subtype, rssi, noise)) {
 927                 /*
 928                  * If we've reached the min dwell time terminate
 929                  * the timer so we'll switch to the next channel.
 930                  */
 931                 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
 932                     time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
 933                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 934                             "%s: chan %3d%c min dwell met (%u > %lu)\n",
 935                             __func__,
 936                             ieee80211_chan2ieee(ic, ic->ic_curchan),
 937                             ieee80211_channel_type_char(ic->ic_curchan),
 938                             ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
 939                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
 940                         /*
 941                          * NB: trigger at next clock tick or wait for the
 942                          * hardware.
 943                          */
 944                         ic->ic_scan_mindwell(ss);
 945                 }
 946         }
 947 }
 948