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 /*
 416  * Taskqueue work to cancel a scan.
 417  *
 418  * Note: for offload scan devices, we may want to call into the
 419  * driver to try and cancel scanning, however it may not be cancelable.
 420  */
 421 static void
 422 cancel_scan(struct ieee80211vap *vap, int any, const char *func)
 423 {
 424         struct ieee80211com *ic = vap->iv_ic;
 425         struct ieee80211_scan_state *ss = ic->ic_scan;
 426         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 427         int signal;
 428
 429         IEEE80211_LOCK(ic);
 430         signal = any ? ISCAN_PAUSE : ISCAN_CANCEL;
 431         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
 432             (any || ss->ss_vap == vap) &&
 433             (ss_priv->ss_iflags & signal) == 0) {
 434                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 435                     "%s: %s %s scan\n", func,
 436                     any ? "pause" : "cancel",
 437                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
 438                         "active" : "passive");
 439
 440                 /* clear bg scan NOPICK */
 441                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
 442                 /* mark request and wake up the scan task */
 443                 scan_signal_locked(ss, signal);
 444         } else {
 445                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 446                     "%s: called; F_SCAN=%d, vap=%s, signal=%d\n",
 447                         func,
 448                         !! (ic->ic_flags & IEEE80211_F_SCAN),
 449                         (ss->ss_vap == vap ? "match" : "nomatch"),
 450                         !! (ss_priv->ss_iflags & signal));
 451         }
 452         IEEE80211_UNLOCK(ic);
 453 }
 454
 455 /*
 456  * Cancel any scan currently going on for the specified vap.
 457  */
 458 static void
 459 ieee80211_swscan_cancel_scan(struct ieee80211vap *vap)
 460 {
 461         cancel_scan(vap, 0, __func__);
 462 }
 463
 464 /*
 465  * Cancel any scan currently going on.
 466  */
 467 static void
 468 ieee80211_swscan_cancel_anyscan(struct ieee80211vap *vap)
 469 {
 470
 471         /* XXX for now - just don't do this per packet. */
 472         if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD)
 473                 return;
 474
 475         cancel_scan(vap, 1, __func__);
 476 }
 477
 478 /*
 479  * Manually switch to the next channel in the channel list.
 480  * Provided for drivers that manage scanning themselves
 481  * (e.g. for firmware-based devices).
 482  */
 483 static void
 484 ieee80211_swscan_scan_next(struct ieee80211vap *vap)
 485 {
 486         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
 487
 488         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
 489
 490         /* wake up the scan task */
 491         scan_signal(ss, 0);
 492 }
 493
 494 /*
 495  * Manually stop a scan that is currently running.
 496  * Provided for drivers that are not able to scan single channels
 497  * (e.g. for firmware-based devices).
 498  */
 499 static void
 500 ieee80211_swscan_scan_done(struct ieee80211vap *vap)
 501 {
 502         struct ieee80211com *ic = vap->iv_ic;
 503         struct ieee80211_scan_state *ss = ic->ic_scan;
 504
 505         IEEE80211_LOCK_ASSERT(ic);
 506
 507         scan_signal_locked(ss, 0);
 508 }
 509
 510 /*
 511  * Probe the current channel, if allowed, while scanning.
 512  * If the channel is not marked passive-only then send
 513  * a probe request immediately.  Otherwise mark state and
 514  * listen for beacons on the channel; if we receive something
 515  * then we'll transmit a probe request.
 516  */
 517 static void
 518 ieee80211_swscan_probe_curchan(struct ieee80211vap *vap, int force)
 519 {
 520         struct ieee80211com *ic = vap->iv_ic;
 521         struct ieee80211_scan_state *ss = ic->ic_scan;
 522         struct ifnet *ifp = vap->iv_ifp;
 523         int i;
 524
 525         /*
 526          * Full-offload scan devices don't require this.
 527          */
 528         if (vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD)
 529                 return;
 530
 531         /*
 532          * Send directed probe requests followed by any
 533          * broadcast probe request.
 534          * XXX remove dependence on ic/vap->iv_bss
 535          */
 536         for (i = 0; i < ss->ss_nssid; i++)
 537                 ieee80211_send_probereq(vap->iv_bss,
 538                         vap->iv_myaddr, ifp->if_broadcastaddr,
 539                         ifp->if_broadcastaddr,
 540                         ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
 541         if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
 542                 ieee80211_send_probereq(vap->iv_bss,
 543                         vap->iv_myaddr, ifp->if_broadcastaddr,
 544                         ifp->if_broadcastaddr,
 545                         "", 0);
 546 }
 547
 548 /*
 549  * Scan curchan.  If this is an active scan and the channel
 550  * is not marked passive then send probe request frame(s).
 551  * Arrange for the channel change after maxdwell ticks.
 552  */
 553 static void
 554 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
 555 {
 556         struct ieee80211vap *vap  = ss->ss_vap;
 557         struct ieee80211com *ic = ss->ss_ic;
 558
 559         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 560             "%s: calling; maxdwell=%lu\n",
 561             __func__,
 562             maxdwell);
 563         IEEE80211_LOCK(ic);
 564         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 565                 ieee80211_probe_curchan(vap, 0);
 566         taskqueue_enqueue_timeout(ic->ic_tq,
 567             &SCAN_PRIVATE(ss)->ss_scan_curchan, maxdwell);
 568         IEEE80211_UNLOCK(ic);
 569 }
 570
 571 static void
 572 scan_signal(struct ieee80211_scan_state *ss, int iflags)
 573 {
 574         struct ieee80211com *ic = ss->ss_ic;
 575
 576         IEEE80211_UNLOCK_ASSERT(ic);
 577
 578         IEEE80211_LOCK(ic);
 579         scan_signal_locked(ss, iflags);
 580         IEEE80211_UNLOCK(ic);
 581 }
 582
 583 static void
 584 scan_signal_locked(struct ieee80211_scan_state *ss, int iflags)
 585 {
 586         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 587         struct timeout_task *scan_task = &ss_priv->ss_scan_curchan;
 588         struct ieee80211com *ic = ss->ss_ic;
 589
 590         IEEE80211_LOCK_ASSERT(ic);
 591
 592         ss_priv->ss_iflags |= iflags;
 593         if (ss_priv->ss_iflags & ISCAN_RUNNING) {
 594                 if (taskqueue_cancel_timeout(ic->ic_tq, scan_task, NULL) == 0)
 595                         taskqueue_enqueue_timeout(ic->ic_tq, scan_task, 0);
 596         }
 597 }
 598
 599 /*
 600  * Handle mindwell requirements completed; initiate a channel
 601  * change to the next channel asap.
 602  */
 603 static void
 604 scan_mindwell(struct ieee80211_scan_state *ss)
 605 {
 606
 607         IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: called\n",
 608             __func__);
 609
 610         scan_signal(ss, 0);
 611 }
 612
 613 static void
 614 scan_start(void *arg, int pending)
 615 {
 616 #define ISCAN_REP       (ISCAN_MINDWELL | ISCAN_DISCARD)
 617         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
 618         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 619         struct ieee80211vap *vap = ss->ss_vap;
 620         struct ieee80211com *ic = ss->ss_ic;
 621
 622         IEEE80211_LOCK(ic);
 623         if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
 624             (ss_priv->ss_iflags & ISCAN_ABORT)) {
 625                 /* Cancelled before we started */
 626                 scan_done(ss, 0);
 627                 return;
 628         }
 629
 630         if (ss->ss_next == ss->ss_last) {
 631                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 632                         "%s: no channels to scan\n", __func__);
 633                 scan_done(ss, 1);
 634                 return;
 635         }
 636
 637         /*
 638          * Put the station into power save mode.
 639          *
 640          * This is only required if we're not a full-offload devices;
 641          * those devices manage scan/traffic differently.
 642          */
 643         if (((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0) &&
 644             vap->iv_opmode == IEEE80211_M_STA &&
 645             vap->iv_state == IEEE80211_S_RUN) {
 646                 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
 647                         /* Enable station power save mode */
 648                         vap->iv_sta_ps(vap, 1);
 649                         /* Wait until null data frame will be ACK'ed */
 650                         mtx_sleep(vap, IEEE80211_LOCK_OBJ(ic), PCATCH,
 651                             "sta_ps", msecs_to_ticks(10));
 652                         if (ss_priv->ss_iflags & ISCAN_ABORT) {
 653                                 scan_done(ss, 0);
 654                                 return;
 655                         }
 656                 }
 657         }
 658
 659         ss_priv->ss_scanend = ticks + ss_priv->ss_duration;
 660
 661         /* XXX scan state can change! Re-validate scan state! */
 662
 663         IEEE80211_UNLOCK(ic);
 664
 665         ic->ic_scan_start(ic);          /* notify driver */
 666
 667         scan_curchan_task(ss, 0);
 668 }
 669
 670 static void
 671 scan_curchan_task(void *arg, int pending)
 672 {
 673         struct ieee80211_scan_state *ss = arg;
 674         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 675         struct ieee80211com *ic = ss->ss_ic;
 676         struct ieee80211_channel *chan;
 677         unsigned long maxdwell;
 678         int scandone;
 679
 680         IEEE80211_LOCK(ic);
 681 end:
 682         scandone = (ss->ss_next >= ss->ss_last) ||
 683             (ss_priv->ss_iflags & ISCAN_CANCEL) != 0;
 684
 685         IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
 686             "%s: loop start; scandone=%d\n",
 687             __func__,
 688             scandone);
 689
 690         if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
 691             (ss_priv->ss_iflags & ISCAN_ABORT) ||
 692              ieee80211_time_after(ticks + ss->ss_mindwell, ss_priv->ss_scanend)) {
 693                 ss_priv->ss_iflags &= ~ISCAN_RUNNING;
 694                 scan_end(ss, scandone);
 695                 return;
 696         } else
 697                 ss_priv->ss_iflags |= ISCAN_RUNNING;
 698
 699         chan = ss->ss_chans[ss->ss_next++];
 700
 701         /*
 702          * Watch for truncation due to the scan end time.
 703          */
 704         if (ieee80211_time_after(ticks + ss->ss_maxdwell, ss_priv->ss_scanend))
 705                 maxdwell = ss_priv->ss_scanend - ticks;
 706         else
 707                 maxdwell = ss->ss_maxdwell;
 708
 709         IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
 710             "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
 711             __func__,
 712             ieee80211_chan2ieee(ic, ic->ic_curchan),
 713             ieee80211_channel_type_char(ic->ic_curchan),
 714             ieee80211_chan2ieee(ic, chan),
 715             ieee80211_channel_type_char(chan),
 716             (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
 717                 (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
 718                 "active" : "passive",
 719             ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
 720
 721         /*
 722          * Potentially change channel and phy mode.
 723          */
 724         ic->ic_curchan = chan;
 725         ic->ic_rt = ieee80211_get_ratetable(chan);
 726         IEEE80211_UNLOCK(ic);
 727         /*
 728          * Perform the channel change and scan unlocked so the driver
 729          * may sleep. Once set_channel returns the hardware has
 730          * completed the channel change.
 731          */
 732         ic->ic_set_channel(ic);
 733         ieee80211_radiotap_chan_change(ic);
 734
 735         /*
 736          * Scan curchan.  Drivers for "intelligent hardware"
 737          * override ic_scan_curchan to tell the device to do
 738          * the work.  Otherwise we manage the work ourselves;
 739          * sending a probe request (as needed), and arming the
 740          * timeout to switch channels after maxdwell ticks.
 741          *
 742          * scan_curchan should only pause for the time required to
 743          * prepare/initiate the hardware for the scan (if at all).
 744          */
 745         ic->ic_scan_curchan(ss, maxdwell);
 746         IEEE80211_LOCK(ic);
 747
 748         /* XXX scan state can change! Re-validate scan state! */
 749
 750         ss_priv->ss_chanmindwell = ticks + ss->ss_mindwell;
 751         /* clear mindwell lock and initial channel change flush */
 752         ss_priv->ss_iflags &= ~ISCAN_REP;
 753
 754         if (ss_priv->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)) {
 755                 taskqueue_cancel_timeout(ic->ic_tq, &ss_priv->ss_scan_curchan,
 756                     NULL);
 757                 goto end;
 758         }
 759
 760         IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: waiting\n",
 761             __func__);
 762         IEEE80211_UNLOCK(ic);
 763 }
 764
 765 static void
 766 scan_end(struct ieee80211_scan_state *ss, int scandone)
 767 {
 768         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 769         struct ieee80211vap *vap = ss->ss_vap;
 770         struct ieee80211com *ic = ss->ss_ic;
 771
 772         IEEE80211_LOCK_ASSERT(ic);
 773
 774         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: out\n", __func__);
 775
 776         if (ss_priv->ss_iflags & ISCAN_ABORT) {
 777                 scan_done(ss, scandone);
 778                 return;
 779         }
 780
 781         IEEE80211_UNLOCK(ic);
 782         ic->ic_scan_end(ic);            /* notify driver */
 783         IEEE80211_LOCK(ic);
 784         /* XXX scan state can change! Re-validate scan state! */
 785
 786         /*
 787          * Since a cancellation may have occurred during one of the
 788          * driver calls (whilst unlocked), update scandone.
 789          */
 790         if (scandone == 0 && (ss_priv->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         ss_priv->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 ((ss_priv->ss_iflags & ISCAN_CANCEL) == 0 &&
 826             !ss->ss_ops->scan_end(ss, vap) &&
 827             (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
 828             ieee80211_time_before(ticks + ss->ss_mindwell, ss_priv->ss_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, ss_priv->ss_scanend);
 834                 ss->ss_next = 0;        /* reset to beginning */
 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, &ss_priv->ss_scan_start);
 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, ss_priv->ss_scanend);
 854
 855         /*
 856          * Since a cancellation may have occurred during one of the
 857          * driver calls (whilst unlocked), update scandone.
 858          */
 859         if (scandone == 0 && (ss_priv->ss_iflags & ISCAN_CANCEL) != 0) {
 860                 /* XXX printf? */
 861                 if_printf(vap->iv_ifp,
 862                     "%s: OOPS! scan cancelled during driver call (2)!\n",
 863                     __func__);
 864                 scandone = 1;
 865         }
 866
 867         scan_done(ss, scandone);
 868 }
 869
 870 static void
 871 scan_done(struct ieee80211_scan_state *ss, int scandone)
 872 {
 873         struct scan_state *ss_priv = SCAN_PRIVATE(ss);
 874         struct ieee80211com *ic = ss->ss_ic;
 875         struct ieee80211vap *vap = ss->ss_vap;
 876
 877         IEEE80211_LOCK_ASSERT(ic);
 878
 879         /*
 880          * Clear the SCAN bit first in case frames are
 881          * pending on the station power save queue.  If
 882          * we defer this then the dispatch of the frames
 883          * may generate a request to cancel scanning.
 884          */
 885         ic->ic_flags &= ~IEEE80211_F_SCAN;
 886
 887         /*
 888          * Drop out of power save mode when a scan has
 889          * completed.  If this scan was prematurely terminated
 890          * because it is a background scan then don't notify
 891          * the ap; we'll either return to scanning after we
 892          * receive the beacon frame or we'll drop out of power
 893          * save mode because the beacon indicates we have frames
 894          * waiting for us.
 895          */
 896         if (scandone) {
 897                 /*
 898                  * If we're not a scan offload device, come back out of
 899                  * station powersave.  Offload devices handle this themselves.
 900                  */
 901                 if ((vap->iv_flags_ext & IEEE80211_FEXT_SCAN_OFFLOAD) == 0)
 902                         vap->iv_sta_ps(vap, 0);
 903                 if (ss->ss_next >= ss->ss_last)
 904                         ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
 905
 906                 /* send 'scan done' event if not interrupted due to traffic. */
 907                 if (!(ss_priv->ss_iflags & ISCAN_INTERRUPT))
 908                         ieee80211_notify_scan_done(vap);
 909         }
 910         ss_priv->ss_iflags &= ~(ISCAN_PAUSE | ISCAN_ABORT);
 911         ss_priv->ss_scanend = 0;
 912         ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
 913         IEEE80211_UNLOCK(ic);
 914 #undef ISCAN_REP
 915 }
 916
 917 /*
 918  * Process a beacon or probe response frame.
 919  */
 920 static void
 921 ieee80211_swscan_add_scan(struct ieee80211vap *vap,
 922         struct ieee80211_channel *curchan,
 923         const struct ieee80211_scanparams *sp,
 924         const struct ieee80211_frame *wh,
 925         int subtype, int rssi, int noise)
 926 {
 927         struct ieee80211com *ic = vap->iv_ic;
 928         struct ieee80211_scan_state *ss = ic->ic_scan;
 929
 930         /* XXX locking */
 931         /*
 932          * Frames received during startup are discarded to avoid
 933          * using scan state setup on the initial entry to the timer
 934          * callback.  This can occur because the device may enable
 935          * rx prior to our doing the initial channel change in the
 936          * timer routine.
 937          */
 938         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
 939                 return;
 940 #ifdef IEEE80211_DEBUG
 941         if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
 942                 ieee80211_scan_dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
 943 #endif
 944         if (ss->ss_ops != NULL &&
 945             ss->ss_ops->scan_add(ss, curchan, sp, wh, subtype, rssi, noise)) {
 946                 /*
 947                  * If we've reached the min dwell time terminate
 948                  * the timer so we'll switch to the next channel.
 949                  */
 950                 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
 951                     ieee80211_time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
 952                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 953                             "%s: chan %3d%c min dwell met (%u > %lu)\n",
 954                             __func__,
 955                             ieee80211_chan2ieee(ic, ic->ic_curchan),
 956                             ieee80211_channel_type_char(ic->ic_curchan),
 957                             ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
 958                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
 959                         /*
 960                          * NB: trigger at next clock tick or wait for the
 961                          * hardware.
 962                          */
 963                         ic->ic_scan_mindwell(ss);
 964                 }
 965         }
 966 }
 967
 968 static struct ieee80211_scan_methods swscan_methods = {
 969         .sc_attach = ieee80211_swscan_attach,
 970         .sc_detach = ieee80211_swscan_detach,
 971         .sc_vattach = ieee80211_swscan_vattach,
 972         .sc_vdetach = ieee80211_swscan_vdetach,
 973         .sc_set_scan_duration = ieee80211_swscan_set_scan_duration,
 974         .sc_start_scan = ieee80211_swscan_start_scan,
 975         .sc_check_scan = ieee80211_swscan_check_scan,
 976         .sc_bg_scan = ieee80211_swscan_bg_scan,
 977         .sc_cancel_scan = ieee80211_swscan_cancel_scan,
 978         .sc_cancel_anyscan = ieee80211_swscan_cancel_anyscan,
 979         .sc_scan_next = ieee80211_swscan_scan_next,
 980         .sc_scan_done = ieee80211_swscan_scan_done,
 981         .sc_scan_probe_curchan = ieee80211_swscan_probe_curchan,
 982         .sc_add_scan = ieee80211_swscan_add_scan
 983 };
 984
 985 /*
 986  * Default scan attach method.
 987  */
 988 void
 989 ieee80211_swscan_attach(struct ieee80211com *ic)
 990 {
 991         struct scan_state *ss;
 992
 993         /*
 994          * Setup the default methods
 995          */
 996         ic->ic_scan_methods = &swscan_methods;
 997
 998         /* Allocate initial scan state */
 999         ss = (struct scan_state *) IEEE80211_MALLOC(sizeof(struct scan_state),
1000                 M_80211_SCAN, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
1001         if (ss == NULL) {
1002                 ic->ic_scan = NULL;
1003                 return;
1004         }
1005         TASK_INIT(&ss->ss_scan_start, 0, scan_start, ss);
1006         TIMEOUT_TASK_INIT(ic->ic_tq, &ss->ss_scan_curchan, 0,
1007             scan_curchan_task, ss);
1008
1009         ic->ic_scan = &ss->base;
1010         ss->base.ss_ic = ic;
1011
1012         ic->ic_scan_curchan = scan_curchan;
1013         ic->ic_scan_mindwell = scan_mindwell;
1014 }