sys/netproto/802_11/wlan/ieee80211_scan.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  * $FreeBSD: head/sys/net80211/ieee80211_scan.c 195618 2009-07-11 15:02:45Z rpaulo $
  26  */
  27
  28 /*
  29  * IEEE 802.11 scanning support.
  30  */
  31 #include "opt_wlan.h"
  32
  33 #include <sys/param.h>
  34 #include <sys/systm.h>
  35 #include <sys/proc.h>
  36 #include <sys/kernel.h>
  37
  38 #include <sys/condvar.h>
  39 #include <sys/socket.h>
  40
  41 #include <net/if.h>
  42 #include <net/if_media.h>
  43 #include <net/ethernet.h>
  44 #include <net/route.h>
  45
  46 #include <netproto/802_11/ieee80211_var.h>
  47
  48 #include <net/bpf.h>
  49
  50 struct scan_state {
  51         struct ieee80211_scan_state base;       /* public state */
  52
  53         u_int           ss_iflags;              /* flags used internally */
  54 #define ISCAN_MINDWELL  0x0001          /* min dwell time reached */
  55 #define ISCAN_DISCARD   0x0002          /* discard rx'd frames */
  56 #define ISCAN_CANCEL    0x0004          /* cancel current scan */
  57 #define ISCAN_ABORT     0x0008          /* end the scan immediately */
  58         unsigned long   ss_chanmindwell;        /* min dwell on curchan */
  59         unsigned long   ss_scanend;             /* time scan must stop */
  60         u_int           ss_duration;            /* duration for next scan */
  61         struct task     ss_scan_task;           /* scan execution */
  62         struct cv       ss_scan_cv;             /* scan signal */
  63         struct callout  ss_scan_timer;          /* scan timer */
  64 };
  65 #define SCAN_PRIVATE(ss)        ((struct scan_state *) ss)
  66
  67 /*
  68  * Amount of time to go off-channel during a background
  69  * scan.  This value should be large enough to catch most
  70  * ap's but short enough that we can return on-channel
  71  * before our listen interval expires.
  72  *
  73  * XXX tunable
  74  * XXX check against configured listen interval
  75  */
  76 #define IEEE80211_SCAN_OFFCHANNEL       msecs_to_ticks(150)
  77
  78 /*
  79  * Roaming-related defaults.  RSSI thresholds are as returned by the
  80  * driver (.5dBm).  Transmit rate thresholds are IEEE rate codes (i.e
  81  * .5M units) or MCS.
  82  */
  83 /* rssi thresholds */
  84 #define ROAM_RSSI_11A_DEFAULT           14      /* 11a bss */
  85 #define ROAM_RSSI_11B_DEFAULT           14      /* 11b bss */
  86 #define ROAM_RSSI_11BONLY_DEFAULT       14      /* 11b-only bss */
  87 /* transmit rate thresholds */
  88 #define ROAM_RATE_11A_DEFAULT           2*12    /* 11a bss */
  89 #define ROAM_RATE_11B_DEFAULT           2*5     /* 11b bss */
  90 #define ROAM_RATE_11BONLY_DEFAULT       2*1     /* 11b-only bss */
  91 #define ROAM_RATE_HALF_DEFAULT          2*6     /* half-width 11a/g bss */
  92 #define ROAM_RATE_QUARTER_DEFAULT       2*3     /* quarter-width 11a/g bss */
  93 #define ROAM_MCS_11N_DEFAULT            (1 | IEEE80211_RATE_MCS) /* 11n bss */
  94
  95 static  void scan_curchan(struct ieee80211_scan_state *, unsigned long);
  96 static  void scan_mindwell(struct ieee80211_scan_state *);
  97 static  void scan_signal_callout(void *);
  98 static  void scan_signal(struct ieee80211_scan_state *ss);
  99 static  void scan_task(void *, int);
 100
 101 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
 102
 103 void
 104 ieee80211_scan_attach(struct ieee80211com *ic)
 105 {
 106         struct scan_state *ss;
 107
 108         ss = (struct scan_state *) kmalloc(sizeof(struct scan_state),
 109                 M_80211_SCAN, M_INTWAIT | M_ZERO);
 110         if (ss == NULL) {
 111                 ic->ic_scan = NULL;
 112                 return;
 113         }
 114         wlan_cv_init(&ss->ss_scan_cv, "scan");
 115         callout_init(&ss->ss_scan_timer);
 116         TASK_INIT(&ss->ss_scan_task, 0, scan_task, ss);
 117         ic->ic_scan = &ss->base;
 118         ss->base.ss_ic = ic;
 119
 120         ic->ic_scan_curchan = scan_curchan;
 121         ic->ic_scan_mindwell = scan_mindwell;
 122 }
 123
 124 void
 125 ieee80211_scan_detach(struct ieee80211com *ic)
 126 {
 127         struct ieee80211_scan_state *ss = ic->ic_scan;
 128
 129         if (ss != NULL) {
 130                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
 131                 scan_signal(ss);
 132                 ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 133                 callout_stop(&SCAN_PRIVATE(ss)->ss_scan_timer);
 134                 KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0,
 135                     ("scan still running"));
 136                 if (ss->ss_ops != NULL) {
 137                         ss->ss_ops->scan_detach(ss);
 138                         ss->ss_ops = NULL;
 139                 }
 140                 ic->ic_scan = NULL;
 141                 kfree(SCAN_PRIVATE(ss), M_80211_SCAN);
 142         }
 143 }
 144
 145 static const struct ieee80211_roamparam defroam[IEEE80211_MODE_MAX] = {
 146         [IEEE80211_MODE_11A]    = { .rssi = ROAM_RSSI_11A_DEFAULT,
 147                                     .rate = ROAM_RATE_11A_DEFAULT },
 148         [IEEE80211_MODE_11G]    = { .rssi = ROAM_RSSI_11B_DEFAULT,
 149                                     .rate = ROAM_RATE_11B_DEFAULT },
 150         [IEEE80211_MODE_11B]    = { .rssi = ROAM_RSSI_11BONLY_DEFAULT,
 151                                     .rate = ROAM_RATE_11BONLY_DEFAULT },
 152         [IEEE80211_MODE_TURBO_A]= { .rssi = ROAM_RSSI_11A_DEFAULT,
 153                                     .rate = ROAM_RATE_11A_DEFAULT },
 154         [IEEE80211_MODE_TURBO_G]= { .rssi = ROAM_RSSI_11A_DEFAULT,
 155                                     .rate = ROAM_RATE_11A_DEFAULT },
 156         [IEEE80211_MODE_STURBO_A]={ .rssi = ROAM_RSSI_11A_DEFAULT,
 157                                     .rate = ROAM_RATE_11A_DEFAULT },
 158         [IEEE80211_MODE_HALF]   = { .rssi = ROAM_RSSI_11A_DEFAULT,
 159                                     .rate = ROAM_RATE_HALF_DEFAULT },
 160         [IEEE80211_MODE_QUARTER]= { .rssi = ROAM_RSSI_11A_DEFAULT,
 161                                     .rate = ROAM_RATE_QUARTER_DEFAULT },
 162         [IEEE80211_MODE_11NA]   = { .rssi = ROAM_RSSI_11A_DEFAULT,
 163                                     .rate = ROAM_MCS_11N_DEFAULT },
 164         [IEEE80211_MODE_11NG]   = { .rssi = ROAM_RSSI_11B_DEFAULT,
 165                                     .rate = ROAM_MCS_11N_DEFAULT },
 166 };
 167
 168 void
 169 ieee80211_scan_vattach(struct ieee80211vap *vap)
 170 {
 171         vap->iv_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz;
 172         vap->iv_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz;
 173         vap->iv_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz;
 174
 175         vap->iv_roaming = IEEE80211_ROAMING_AUTO;
 176         memcpy(vap->iv_roamparms, defroam, sizeof(defroam));
 177 }
 178
 179 void
 180 ieee80211_scan_vdetach(struct ieee80211vap *vap)
 181 {
 182         struct ieee80211com *ic = vap->iv_ic;
 183         struct ieee80211_scan_state *ss;
 184
 185         ss = ic->ic_scan;
 186         if (ss != NULL && ss->ss_vap == vap) {
 187                 if (ic->ic_flags & IEEE80211_F_SCAN) {
 188                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
 189                         scan_signal(ss);
 190                 }
 191                 if (ss->ss_ops != NULL) {
 192                         ss->ss_ops->scan_detach(ss);
 193                         ss->ss_ops = NULL;
 194                 }
 195                 ss->ss_vap = NULL;
 196         }
 197 }
 198
 199 /*
 200  * Simple-minded scanner module support.
 201  */
 202 static const char *scan_modnames[IEEE80211_OPMODE_MAX] = {
 203         "wlan_scan_sta",        /* IEEE80211_M_IBSS */
 204         "wlan_scan_sta",        /* IEEE80211_M_STA */
 205         "wlan_scan_wds",        /* IEEE80211_M_WDS */
 206         "wlan_scan_sta",        /* IEEE80211_M_AHDEMO */
 207         "wlan_scan_ap",         /* IEEE80211_M_HOSTAP */
 208         "wlan_scan_monitor",    /* IEEE80211_M_MONITOR */
 209         "wlan_scan_sta",        /* IEEE80211_M_MBSS */
 210 };
 211 static const struct ieee80211_scanner *scanners[IEEE80211_OPMODE_MAX];
 212
 213 const struct ieee80211_scanner *
 214 ieee80211_scanner_get(enum ieee80211_opmode mode)
 215 {
 216         if (mode >= IEEE80211_OPMODE_MAX)
 217                 return NULL;
 218         if (scanners[mode] == NULL)
 219                 ieee80211_load_module(scan_modnames[mode]);
 220         return scanners[mode];
 221 }
 222
 223 void
 224 ieee80211_scanner_register(enum ieee80211_opmode mode,
 225         const struct ieee80211_scanner *scan)
 226 {
 227         if (mode >= IEEE80211_OPMODE_MAX)
 228                 return;
 229         scanners[mode] = scan;
 230 }
 231
 232 void
 233 ieee80211_scanner_unregister(enum ieee80211_opmode mode,
 234         const struct ieee80211_scanner *scan)
 235 {
 236         if (mode >= IEEE80211_OPMODE_MAX)
 237                 return;
 238         if (scanners[mode] == scan)
 239                 scanners[mode] = NULL;
 240 }
 241
 242 void
 243 ieee80211_scanner_unregister_all(const struct ieee80211_scanner *scan)
 244 {
 245         int m;
 246
 247         for (m = 0; m < IEEE80211_OPMODE_MAX; m++)
 248                 if (scanners[m] == scan)
 249                         scanners[m] = NULL;
 250 }
 251
 252 /*
 253  * Update common scanner state to reflect the current
 254  * operating mode.  This is called when the state machine
 255  * is transitioned to RUN state w/o scanning--e.g. when
 256  * operating in monitor mode.  The purpose of this is to
 257  * ensure later callbacks find ss_ops set to properly
 258  * reflect current operating mode.
 259  */
 260 static void
 261 scan_update_locked(struct ieee80211vap *vap,
 262         const struct ieee80211_scanner *scan)
 263 {
 264         struct ieee80211com *ic = vap->iv_ic;
 265         struct ieee80211_scan_state *ss = ic->ic_scan;
 266
 267 #ifdef IEEE80211_DEBUG
 268         if (ss->ss_vap != vap || ss->ss_ops != scan) {
 269                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 270                     "%s: current scanner is <%s:%s>, switch to <%s:%s>\n",
 271                     __func__,
 272                     ss->ss_vap != NULL ?
 273                         ss->ss_vap->iv_ifp->if_xname : "none",
 274                     ss->ss_vap != NULL ?
 275                         ieee80211_opmode_name[ss->ss_vap->iv_opmode] : "none",
 276                     vap->iv_ifp->if_xname,
 277                     ieee80211_opmode_name[vap->iv_opmode]);
 278         }
 279 #endif
 280         ss->ss_vap = vap;
 281         if (ss->ss_ops != scan) {
 282                 /*
 283                  * Switch scanners; detach old, attach new.  Special
 284                  * case where a single scan module implements multiple
 285                  * policies by using different scan ops but a common
 286                  * core.  We assume if the old and new attach methods
 287                  * are identical then it's ok to just change ss_ops
 288                  * and not flush the internal state of the module.
 289                  */
 290                 if (scan == NULL || ss->ss_ops == NULL ||
 291                     ss->ss_ops->scan_attach != scan->scan_attach) {
 292                         if (ss->ss_ops != NULL)
 293                                 ss->ss_ops->scan_detach(ss);
 294                         if (scan != NULL && !scan->scan_attach(ss)) {
 295                                 /* XXX attach failure */
 296                                 /* XXX stat+msg */
 297                                 scan = NULL;
 298                         }
 299                 }
 300                 ss->ss_ops = scan;
 301         }
 302 }
 303
 304 static char
 305 channel_type(const struct ieee80211_channel *c)
 306 {
 307         if (IEEE80211_IS_CHAN_ST(c))
 308                 return 'S';
 309         if (IEEE80211_IS_CHAN_108A(c))
 310                 return 'T';
 311         if (IEEE80211_IS_CHAN_108G(c))
 312                 return 'G';
 313         if (IEEE80211_IS_CHAN_HT(c))
 314                 return 'n';
 315         if (IEEE80211_IS_CHAN_A(c))
 316                 return 'a';
 317         if (IEEE80211_IS_CHAN_ANYG(c))
 318                 return 'g';
 319         if (IEEE80211_IS_CHAN_B(c))
 320                 return 'b';
 321         return 'f';
 322 }
 323
 324 void
 325 ieee80211_scan_dump_channels(const struct ieee80211_scan_state *ss)
 326 {
 327         struct ieee80211com *ic = ss->ss_ic;
 328         const char *sep;
 329         int i;
 330
 331         sep = "";
 332         for (i = ss->ss_next; i < ss->ss_last; i++) {
 333                 const struct ieee80211_channel *c = ss->ss_chans[i];
 334
 335                 kprintf("%s%u%c", sep, ieee80211_chan2ieee(ic, c),
 336                         channel_type(c));
 337                 sep = ", ";
 338         }
 339 }
 340
 341 #ifdef IEEE80211_DEBUG
 342 static void
 343 scan_dump(struct ieee80211_scan_state *ss)
 344 {
 345         struct ieee80211vap *vap = ss->ss_vap;
 346
 347         if_printf(vap->iv_ifp, "scan set ");
 348         ieee80211_scan_dump_channels(ss);
 349         kprintf(" dwell min %lums max %lums\n",
 350             ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(ss->ss_maxdwell));
 351 }
 352 #endif /* IEEE80211_DEBUG */
 353
 354 static void
 355 copy_ssid(struct ieee80211vap *vap, struct ieee80211_scan_state *ss,
 356         int nssid, const struct ieee80211_scan_ssid ssids[])
 357 {
 358         if (nssid > IEEE80211_SCAN_MAX_SSID) {
 359                 /* XXX printf */
 360                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 361                     "%s: too many ssid %d, ignoring all of them\n",
 362                     __func__, nssid);
 363                 return;
 364         }
 365         memcpy(ss->ss_ssid, ssids, nssid * sizeof(ssids[0]));
 366         ss->ss_nssid = nssid;
 367 }
 368
 369 /*
 370  * Start a scan unless one is already going.
 371  */
 372 static int
 373 start_scan_locked(const struct ieee80211_scanner *scan,
 374         struct ieee80211vap *vap, int flags, u_int duration,
 375         u_int mindwell, u_int maxdwell,
 376         u_int nssid, const struct ieee80211_scan_ssid ssids[])
 377 {
 378         struct ieee80211com *ic = vap->iv_ic;
 379         struct ieee80211_scan_state *ss = ic->ic_scan;
 380
 381         if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
 382                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 383                     "%s: scan inhibited by pending channel change\n", __func__);
 384         } else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
 385                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 386                     "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
 387                     , __func__
 388                     , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
 389                     , duration, mindwell, maxdwell
 390                     , ieee80211_phymode_name[vap->iv_des_mode]
 391                     , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
 392                     , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
 393                     , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
 394                     , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
 395                     , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
 396                     , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
 397                 );
 398
 399                 scan_update_locked(vap, scan);
 400                 if (ss->ss_ops != NULL) {
 401                         if ((flags & IEEE80211_SCAN_NOSSID) == 0)
 402                                 copy_ssid(vap, ss, nssid, ssids);
 403
 404                         /* NB: top 4 bits for internal use */
 405                         ss->ss_flags = flags & 0xfff;
 406                         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 407                                 vap->iv_stats.is_scan_active++;
 408                         else
 409                                 vap->iv_stats.is_scan_passive++;
 410                         if (flags & IEEE80211_SCAN_FLUSH)
 411                                 ss->ss_ops->scan_flush(ss);
 412
 413                         /* NB: flush frames rx'd before 1st channel change */
 414                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
 415                         SCAN_PRIVATE(ss)->ss_duration = duration;
 416                         ss->ss_next = 0;
 417                         ss->ss_mindwell = mindwell;
 418                         ss->ss_maxdwell = maxdwell;
 419                         /* NB: scan_start must be before the scan runtask */
 420                         ss->ss_ops->scan_start(ss, vap);
 421 #ifdef IEEE80211_DEBUG
 422                         if (ieee80211_msg_scan(vap))
 423                                 scan_dump(ss);
 424 #endif /* IEEE80211_DEBUG */
 425                         ic->ic_flags |= IEEE80211_F_SCAN;
 426                         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 427                 }
 428         } else {
 429                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 430                     "%s: %s scan already in progress\n", __func__,
 431                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
 432         }
 433         return (ic->ic_flags & IEEE80211_F_SCAN);
 434 }
 435
 436 /*
 437  * Start a scan unless one is already going.
 438  */
 439 int
 440 ieee80211_start_scan(struct ieee80211vap *vap, int flags,
 441         u_int duration, u_int mindwell, u_int maxdwell,
 442         u_int nssid, const struct ieee80211_scan_ssid ssids[])
 443 {
 444         const struct ieee80211_scanner *scan;
 445         int result;
 446
 447         scan = ieee80211_scanner_get(vap->iv_opmode);
 448         if (scan == NULL) {
 449                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 450                     "%s: no scanner support for %s mode\n",
 451                     __func__, ieee80211_opmode_name[vap->iv_opmode]);
 452                 /* XXX stat */
 453                 return 0;
 454         }
 455
 456         result = start_scan_locked(scan, vap, flags, duration,
 457             mindwell, maxdwell, nssid, ssids);
 458
 459         return result;
 460 }
 461
 462 /*
 463  * Check the scan cache for an ap/channel to use; if that
 464  * fails then kick off a new scan.
 465  */
 466 int
 467 ieee80211_check_scan(struct ieee80211vap *vap, int flags,
 468         u_int duration, u_int mindwell, u_int maxdwell,
 469         u_int nssid, const struct ieee80211_scan_ssid ssids[])
 470 {
 471         struct ieee80211com *ic = vap->iv_ic;
 472         struct ieee80211_scan_state *ss = ic->ic_scan;
 473         const struct ieee80211_scanner *scan;
 474         int result;
 475
 476         scan = ieee80211_scanner_get(vap->iv_opmode);
 477         if (scan == NULL) {
 478                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 479                     "%s: no scanner support for %d mode\n",
 480                     __func__, vap->iv_opmode);
 481                 /* XXX stat */
 482                 return 0;
 483         }
 484
 485         /*
 486          * Check if there's a list of scan candidates already.
 487          * XXX want more than the ap we're currently associated with
 488          */
 489
 490         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 491             "%s: %s scan, %s%s%s%s%s\n"
 492             , __func__
 493             , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
 494             , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
 495             , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
 496             , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
 497             , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
 498             , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
 499         );
 500
 501         if (ss->ss_ops != scan) {
 502                 /* XXX re-use cache contents? e.g. adhoc<->sta */
 503                 flags |= IEEE80211_SCAN_FLUSH;
 504         }
 505         scan_update_locked(vap, scan);
 506         if (ss->ss_ops != NULL) {
 507                 /* XXX verify ss_ops matches vap->iv_opmode */
 508                 if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
 509                         /*
 510                          * Update the ssid list and mark flags so if
 511                          * we call start_scan it doesn't duplicate work.
 512                          */
 513                         copy_ssid(vap, ss, nssid, ssids);
 514                         flags |= IEEE80211_SCAN_NOSSID;
 515                 }
 516                 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
 517                     (flags & IEEE80211_SCAN_FLUSH) == 0 &&
 518                     time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
 519                         /*
 520                          * We're not currently scanning and the cache is
 521                          * deemed hot enough to consult.  Lock out others
 522                          * by marking IEEE80211_F_SCAN while we decide if
 523                          * something is already in the scan cache we can
 524                          * use.  Also discard any frames that might come
 525                          * in while temporarily marked as scanning.
 526                          */
 527                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
 528                         ic->ic_flags |= IEEE80211_F_SCAN;
 529
 530                         /* NB: need to use supplied flags in check */
 531                         ss->ss_flags = flags & 0xff;
 532                         result = ss->ss_ops->scan_end(ss, vap);
 533
 534                         ic->ic_flags &= ~IEEE80211_F_SCAN;
 535                         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
 536                         if (result) {
 537                                 ieee80211_notify_scan_done(vap);
 538                                 return 1;
 539                         }
 540                 }
 541         }
 542         result = start_scan_locked(scan, vap, flags, duration,
 543             mindwell, maxdwell, nssid, ssids);
 544
 545         return result;
 546 }
 547
 548 /*
 549  * Check the scan cache for an ap/channel to use; if that fails
 550  * then kick off a scan using the current settings.
 551  */
 552 int
 553 ieee80211_check_scan_current(struct ieee80211vap *vap)
 554 {
 555         return ieee80211_check_scan(vap,
 556             IEEE80211_SCAN_ACTIVE,
 557             IEEE80211_SCAN_FOREVER, 0, 0,
 558             vap->iv_des_nssid, vap->iv_des_ssid);
 559 }
 560
 561 /*
 562  * Restart a previous scan.  If the previous scan completed
 563  * then we start again using the existing channel list.
 564  */
 565 int
 566 ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
 567 {
 568         struct ieee80211com *ic = vap->iv_ic;
 569         struct ieee80211_scan_state *ss = ic->ic_scan;
 570         const struct ieee80211_scanner *scan;
 571
 572         scan = ieee80211_scanner_get(vap->iv_opmode);
 573         if (scan == NULL) {
 574                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 575                     "%s: no scanner support for %d mode\n",
 576                     __func__, vap->iv_opmode);
 577                 /* XXX stat */
 578                 return 0;
 579         }
 580
 581         if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
 582                 u_int duration;
 583                 /*
 584                  * Go off-channel for a fixed interval that is large
 585                  * enough to catch most ap's but short enough that
 586                  * we can return on-channel before our listen interval
 587                  * expires.
 588                  */
 589                 duration = IEEE80211_SCAN_OFFCHANNEL;
 590
 591                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 592                     "%s: %s scan, ticks %u duration %u\n", __func__,
 593                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
 594                     ticks, duration);
 595
 596                 scan_update_locked(vap, scan);
 597                 if (ss->ss_ops != NULL) {
 598                         ss->ss_vap = vap;
 599                         /*
 600                          * A background scan does not select a new sta; it
 601                          * just refreshes the scan cache.  Also, indicate
 602                          * the scan logic should follow the beacon schedule:
 603                          * we go off-channel and scan for a while, then
 604                          * return to the bss channel to receive a beacon,
 605                          * then go off-channel again.  All during this time
 606                          * we notify the ap we're in power save mode.  When
 607                          * the scan is complete we leave power save mode.
 608                          * If any beacon indicates there are frames pending
 609                          * for us then we drop out of power save mode
 610                          * (and background scan) automatically by way of the
 611                          * usual sta power save logic.
 612                          */
 613                         ss->ss_flags |= IEEE80211_SCAN_NOPICK
 614                                      |  IEEE80211_SCAN_BGSCAN
 615                                      |  flags
 616                                      ;
 617                         /* if previous scan completed, restart */
 618                         if (ss->ss_next >= ss->ss_last) {
 619                                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 620                                         vap->iv_stats.is_scan_active++;
 621                                 else
 622                                         vap->iv_stats.is_scan_passive++;
 623                                 /*
 624                                  * NB: beware of the scan cache being flushed;
 625                                  *     if the channel list is empty use the
 626                                  *     scan_start method to populate it.
 627                                  */
 628                                 ss->ss_next = 0;
 629                                 if (ss->ss_last != 0)
 630                                         ss->ss_ops->scan_restart(ss, vap);
 631                                 else {
 632                                         ss->ss_ops->scan_start(ss, vap);
 633 #ifdef IEEE80211_DEBUG
 634                                         if (ieee80211_msg_scan(vap))
 635                                                 scan_dump(ss);
 636 #endif /* IEEE80211_DEBUG */
 637                                 }
 638                         }
 639                         /* NB: flush frames rx'd before 1st channel change */
 640                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
 641                         SCAN_PRIVATE(ss)->ss_duration = duration;
 642                         ss->ss_maxdwell = duration;
 643                         ic->ic_flags |= IEEE80211_F_SCAN;
 644                         ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
 645                         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 646                 } else {
 647                         /* XXX msg+stat */
 648                 }
 649         } else {
 650                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 651                     "%s: %s scan already in progress\n", __func__,
 652                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
 653         }
 654
 655         /* NB: racey, does it matter? */
 656         return (ic->ic_flags & IEEE80211_F_SCAN);
 657 }
 658
 659 /*
 660  * Cancel any scan currently going on for the specified vap.
 661  */
 662 void
 663 ieee80211_cancel_scan(struct ieee80211vap *vap)
 664 {
 665         struct ieee80211com *ic = vap->iv_ic;
 666         struct ieee80211_scan_state *ss = ic->ic_scan;
 667
 668         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
 669             ss->ss_vap == vap &&
 670             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
 671                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 672                     "%s: cancel %s scan\n", __func__,
 673                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
 674                         "active" : "passive");
 675
 676                 /* clear bg scan NOPICK and mark cancel request */
 677                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
 678                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
 679                 /* wake up the scan task */
 680                 scan_signal(ss);
 681         }
 682 }
 683
 684 /*
 685  * Cancel any scan currently going on.
 686  */
 687 void
 688 ieee80211_cancel_anyscan(struct ieee80211vap *vap)
 689 {
 690         struct ieee80211com *ic = vap->iv_ic;
 691         struct ieee80211_scan_state *ss = ic->ic_scan;
 692
 693         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
 694             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
 695                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 696                     "%s: cancel %s scan\n", __func__,
 697                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
 698                         "active" : "passive");
 699
 700                 /* clear bg scan NOPICK and mark cancel request */
 701                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
 702                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
 703                 /* wake up the scan task */
 704                 scan_signal(ss);
 705         }
 706 }
 707
 708 /*
 709  * Public access to scan_next for drivers that manage
 710  * scanning themselves (e.g. for firmware-based devices).
 711  */
 712 void
 713 ieee80211_scan_next(struct ieee80211vap *vap)
 714 {
 715         struct ieee80211com *ic = vap->iv_ic;
 716         struct ieee80211_scan_state *ss = ic->ic_scan;
 717
 718         /* wake up the scan task */
 719         scan_signal(ss);
 720 }
 721
 722 /*
 723  * Public access to scan_next for drivers that are not able to scan single
 724  * channels (e.g. for firmware-based devices).
 725  */
 726 void
 727 ieee80211_scan_done(struct ieee80211vap *vap)
 728 {
 729         struct ieee80211com *ic = vap->iv_ic;
 730         struct ieee80211_scan_state *ss;
 731
 732         ss = ic->ic_scan;
 733         ss->ss_next = ss->ss_last; /* all channels are complete */
 734         scan_signal(ss);
 735 }
 736
 737 /*
 738  * Probe the curent channel, if allowed, while scanning.
 739  * If the channel is not marked passive-only then send
 740  * a probe request immediately.  Otherwise mark state and
 741  * listen for beacons on the channel; if we receive something
 742  * then we'll transmit a probe request.
 743  */
 744 void
 745 ieee80211_probe_curchan(struct ieee80211vap *vap, int force)
 746 {
 747         struct ieee80211com *ic = vap->iv_ic;
 748         struct ieee80211_scan_state *ss = ic->ic_scan;
 749         struct ifnet *ifp = vap->iv_ifp;
 750         int i;
 751
 752         if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
 753                 ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
 754                 return;
 755         }
 756         /*
 757          * Send directed probe requests followed by any
 758          * broadcast probe request.
 759          * XXX remove dependence on ic/vap->iv_bss
 760          */
 761         for (i = 0; i < ss->ss_nssid; i++)
 762                 ieee80211_send_probereq(vap->iv_bss,
 763                         vap->iv_myaddr, ifp->if_broadcastaddr,
 764                         ifp->if_broadcastaddr,
 765                         ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
 766         if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
 767                 ieee80211_send_probereq(vap->iv_bss,
 768                         vap->iv_myaddr, ifp->if_broadcastaddr,
 769                         ifp->if_broadcastaddr,
 770                         "", 0);
 771 }
 772
 773 /*
 774  * Scan curchan.  If this is an active scan and the channel
 775  * is not marked passive then send probe request frame(s).
 776  * Arrange for the channel change after maxdwell ticks.
 777  */
 778 static void
 779 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
 780 {
 781         struct ieee80211vap *vap  = ss->ss_vap;
 782
 783         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 784                 ieee80211_probe_curchan(vap, 0);
 785         callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
 786                       maxdwell, scan_signal_callout, ss);
 787 }
 788
 789 static void
 790 scan_signal_callout(void *arg)
 791 {
 792         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
 793
 794         wlan_serialize_enter();
 795         scan_signal(ss);
 796         wlan_serialize_exit();
 797 }
 798
 799 static void
 800 scan_signal(struct ieee80211_scan_state *ss)
 801 {
 802         wlan_cv_signal(&SCAN_PRIVATE(ss)->ss_scan_cv, 0);
 803 }
 804
 805 /*
 806  * Handle mindwell requirements completed; initiate a channel
 807  * change to the next channel asap.
 808  */
 809 static void
 810 scan_mindwell(struct ieee80211_scan_state *ss)
 811 {
 812         scan_signal(ss);
 813 }
 814
 815 static void
 816 scan_task(void *arg, int pending)
 817 {
 818 #define ISCAN_REP       (ISCAN_MINDWELL | ISCAN_DISCARD)
 819         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
 820         struct ieee80211vap *vap;
 821         struct ieee80211com *ic;
 822         struct ieee80211_channel *chan;
 823         unsigned long maxdwell, scanend;
 824         int scandone = 0;
 825
 826         wlan_serialize_enter();
 827         vap = ss->ss_vap;
 828         ic = ss->ss_ic;
 829
 830         if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
 831             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
 832                 /* Cancelled before we started */
 833                 goto done;
 834         }
 835
 836         if (ss->ss_next == ss->ss_last) {
 837                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 838                         "%s: no channels to scan\n", __func__);
 839                 scandone = 1;
 840                 goto done;
 841         }
 842
 843         if (vap->iv_opmode == IEEE80211_M_STA &&
 844             vap->iv_state == IEEE80211_S_RUN) {
 845                 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
 846                         /* Enable station power save mode */
 847                         ieee80211_sta_pwrsave(vap, 1);
 848                         /*
 849                          * Use an 1ms delay so the null data frame has a chance
 850                          * to go out.  Minimum one tick.
 851                          * XXX Should use M_TXCB mechanism to eliminate this.
 852                          */
 853                         wlan_cv_timedwait(&SCAN_PRIVATE(ss)->ss_scan_cv,
 854                                           hz / 1000 + 1);
 855                         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
 856                                 goto done;
 857                 }
 858         }
 859
 860         scanend = ticks + SCAN_PRIVATE(ss)->ss_duration;
 861         ic->ic_scan_start(ic);          /* notify driver */
 862
 863         for (;;) {
 864                 scandone = (ss->ss_next >= ss->ss_last) ||
 865                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0;
 866                 if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
 867                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT) ||
 868                      time_after(ticks + ss->ss_mindwell, scanend))
 869                         break;
 870
 871                 chan = ss->ss_chans[ss->ss_next++];
 872
 873                 /*
 874                  * Watch for truncation due to the scan end time.
 875                  */
 876                 if (time_after(ticks + ss->ss_maxdwell, scanend))
 877                         maxdwell = scanend - ticks;
 878                 else
 879                         maxdwell = ss->ss_maxdwell;
 880
 881                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 882                     "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
 883                     __func__,
 884                     ieee80211_chan2ieee(ic, ic->ic_curchan),
 885                         channel_type(ic->ic_curchan),
 886                     ieee80211_chan2ieee(ic, chan), channel_type(chan),
 887                     (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
 888                         (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
 889                         "active" : "passive",
 890                     ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
 891
 892                 /*
 893                  * Potentially change channel and phy mode.
 894                  */
 895                 ic->ic_curchan = chan;
 896                 ic->ic_rt = ieee80211_get_ratetable(chan);
 897                 /*
 898                  * Perform the channel change and scan unlocked so the driver
 899                  * may sleep. Once set_channel returns the hardware has
 900                  * completed the channel change.
 901                  */
 902                 ic->ic_set_channel(ic);
 903                 ieee80211_radiotap_chan_change(ic);
 904
 905                 /*
 906                  * Scan curchan.  Drivers for "intelligent hardware"
 907                  * override ic_scan_curchan to tell the device to do
 908                  * the work.  Otherwise we manage the work outselves;
 909                  * sending a probe request (as needed), and arming the
 910                  * timeout to switch channels after maxdwell ticks.
 911                  *
 912                  * scan_curchan should only pause for the time required to
 913                  * prepare/initiate the hardware for the scan (if at all), the
 914                  * below condvar is used to sleep for the channels dwell time
 915                  * and allows it to be signalled for abort.
 916                  */
 917                 ic->ic_scan_curchan(ss, maxdwell);
 918
 919                 SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell;
 920                 /* clear mindwell lock and initial channel change flush */
 921                 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
 922
 923                 if ((SCAN_PRIVATE(ss)->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)))
 924                         continue;
 925
 926                 /* Wait to be signalled to scan the next channel */
 927                 wlan_cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv);
 928         }
 929         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
 930                 goto done;
 931
 932         ic->ic_scan_end(ic);            /* notify driver */
 933
 934         /*
 935          * Record scan complete time.  Note that we also do
 936          * this when canceled so any background scan will
 937          * not be restarted for a while.
 938          */
 939         if (scandone)
 940                 ic->ic_lastscan = ticks;
 941         /* return to the bss channel */
 942         if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
 943             ic->ic_curchan != ic->ic_bsschan) {
 944                 ieee80211_setupcurchan(ic, ic->ic_bsschan);
 945                 ic->ic_set_channel(ic);
 946                 ieee80211_radiotap_chan_change(ic);
 947         }
 948         /* clear internal flags and any indication of a pick */
 949         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
 950         ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
 951
 952         /*
 953          * If not canceled and scan completed, do post-processing.
 954          * If the callback function returns 0, then it wants to
 955          * continue/restart scanning.  Unfortunately we needed to
 956          * notify the driver to end the scan above to avoid having
 957          * rx frames alter the scan candidate list.
 958          */
 959         if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 &&
 960             !ss->ss_ops->scan_end(ss, vap) &&
 961             (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
 962             time_before(ticks + ss->ss_mindwell, scanend)) {
 963                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 964                     "%s: done, restart "
 965                     "[ticks %u, dwell min %lu scanend %lu]\n",
 966                     __func__,
 967                     ticks, ss->ss_mindwell, scanend);
 968                 ss->ss_next = 0;        /* reset to begining */
 969                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 970                         vap->iv_stats.is_scan_active++;
 971                 else
 972                         vap->iv_stats.is_scan_passive++;
 973
 974                 ss->ss_ops->scan_restart(ss, vap);      /* XXX? */
 975                 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 976                 goto done2;
 977         }
 978
 979         /* past here, scandone is ``true'' if not in bg mode */
 980         if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
 981                 scandone = 1;
 982
 983         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 984             "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
 985             __func__, scandone ? "done" : "stopped",
 986             ticks, ss->ss_mindwell, scanend);
 987
 988         /*
 989          * Clear the SCAN bit first in case frames are
 990          * pending on the station power save queue.  If
 991          * we defer this then the dispatch of the frames
 992          * may generate a request to cancel scanning.
 993          */
 994 done:
 995         ic->ic_flags &= ~IEEE80211_F_SCAN;
 996         /*
 997          * Drop out of power save mode when a scan has
 998          * completed.  If this scan was prematurely terminated
 999          * because it is a background scan then don't notify
1000          * the ap; we'll either return to scanning after we
1001          * receive the beacon frame or we'll drop out of power
1002          * save mode because the beacon indicates we have frames
1003          * waiting for us.
1004          */
1005         if (scandone) {
1006                 ieee80211_sta_pwrsave(vap, 0);
1007                 if (ss->ss_next >= ss->ss_last) {
1008                         ieee80211_notify_scan_done(vap);
1009                         ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
1010                 }
1011         }
1012         SCAN_PRIVATE(ss)->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
1013         ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
1014 done2:
1015         wlan_serialize_exit();
1016 #undef ISCAN_REP
1017 }
1018
1019 #ifdef IEEE80211_DEBUG
1020 static void
1021 dump_country(const uint8_t *ie)
1022 {
1023         const struct ieee80211_country_ie *cie =
1024            (const struct ieee80211_country_ie *) ie;
1025         int i, nbands, schan, nchan;
1026
1027         if (cie->len < 3) {
1028                 kprintf(" <bogus country ie, len %d>", cie->len);
1029                 return;
1030         }
1031         kprintf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]);
1032         nbands = (cie->len - 3) / sizeof(cie->band[0]);
1033         for (i = 0; i < nbands; i++) {
1034                 schan = cie->band[i].schan;
1035                 nchan = cie->band[i].nchan;
1036                 if (nchan != 1)
1037                         kprintf(" %u-%u,%u", schan, schan + nchan-1,
1038                             cie->band[i].maxtxpwr);
1039                 else
1040                         kprintf(" %u,%u", schan, cie->band[i].maxtxpwr);
1041         }
1042         kprintf("]");
1043 }
1044
1045 static void
1046 dump_probe_beacon(uint8_t subtype, int isnew,
1047         const uint8_t mac[IEEE80211_ADDR_LEN],
1048         const struct ieee80211_scanparams *sp, int rssi)
1049 {
1050         char ethstr[ETHER_ADDRSTRLEN + 1];
1051
1052         kprintf("[%s] %s%s on chan %u (bss chan %u) ",
1053             kether_ntoa(mac, ethstr), isnew ? "new " : "",
1054             ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT],
1055             sp->chan, sp->bchan);
1056         ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
1057         kprintf(" rssi %d\n", rssi);
1058
1059         if (isnew) {
1060                 kprintf("[%s] caps 0x%x bintval %u erp 0x%x",
1061                         kether_ntoa(mac, ethstr), sp->capinfo, sp->bintval, sp->erp);
1062                 if (sp->country != NULL)
1063                         dump_country(sp->country);
1064                 kprintf("\n");
1065         }
1066 }
1067 #endif /* IEEE80211_DEBUG */
1068
1069 /*
1070  * Process a beacon or probe response frame.
1071  */
1072 void
1073 ieee80211_add_scan(struct ieee80211vap *vap,
1074         const struct ieee80211_scanparams *sp,
1075         const struct ieee80211_frame *wh,
1076         int subtype, int rssi, int noise)
1077 {
1078         struct ieee80211com *ic = vap->iv_ic;
1079         struct ieee80211_scan_state *ss = ic->ic_scan;
1080
1081         /* XXX locking */
1082         /*
1083          * Frames received during startup are discarded to avoid
1084          * using scan state setup on the initial entry to the timer
1085          * callback.  This can occur because the device may enable
1086          * rx prior to our doing the initial channel change in the
1087          * timer routine.
1088          */
1089         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
1090                 return;
1091 #ifdef IEEE80211_DEBUG
1092         if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
1093                 dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
1094 #endif
1095         if (ss->ss_ops != NULL &&
1096             ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise)) {
1097                 /*
1098                  * If we've reached the min dwell time terminate
1099                  * the timer so we'll switch to the next channel.
1100                  */
1101                 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
1102                     time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
1103                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1104                             "%s: chan %3d%c min dwell met (%u > %lu)\n",
1105                             __func__,
1106                             ieee80211_chan2ieee(ic, ic->ic_curchan),
1107                                 channel_type(ic->ic_curchan),
1108                             ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
1109                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
1110                         /*
1111                          * NB: trigger at next clock tick or wait for the
1112                          * hardware.
1113                          */
1114                         ic->ic_scan_mindwell(ss);
1115                 }
1116         }
1117 }
1118
1119 /*
1120  * Timeout/age scan cache entries; called from sta timeout
1121  * timer (XXX should be self-contained).
1122  */
1123 void
1124 ieee80211_scan_timeout(struct ieee80211com *ic)
1125 {
1126         struct ieee80211_scan_state *ss = ic->ic_scan;
1127
1128         if (ss->ss_ops != NULL)
1129                 ss->ss_ops->scan_age(ss);
1130 }
1131
1132 /*
1133  * Mark a scan cache entry after a successful associate.
1134  */
1135 void
1136 ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
1137 {
1138         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1139
1140         if (ss->ss_ops != NULL) {
1141                 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN,
1142                         mac, "%s",  __func__);
1143                 ss->ss_ops->scan_assoc_success(ss, mac);
1144         }
1145 }
1146
1147 /*
1148  * Demerit a scan cache entry after failing to associate.
1149  */
1150 void
1151 ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
1152         const uint8_t mac[], int reason)
1153 {
1154         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1155
1156         if (ss->ss_ops != NULL) {
1157                 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac,
1158                         "%s: reason %u", __func__, reason);
1159                 ss->ss_ops->scan_assoc_fail(ss, mac, reason);
1160         }
1161 }
1162
1163 /*
1164  * Iterate over the contents of the scan cache.
1165  */
1166 void
1167 ieee80211_scan_iterate(struct ieee80211vap *vap,
1168         ieee80211_scan_iter_func *f, void *arg)
1169 {
1170         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1171
1172         if (ss->ss_ops != NULL)
1173                 ss->ss_ops->scan_iterate(ss, f, arg);
1174 }
1175
1176 /*
1177  * Flush the contents of the scan cache.
1178  */
1179 void
1180 ieee80211_scan_flush(struct ieee80211vap *vap)
1181 {
1182         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1183
1184         if (ss->ss_ops != NULL && ss->ss_vap == vap) {
1185                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n",  __func__);
1186                 ss->ss_ops->scan_flush(ss);
1187         }
1188 }
1189
1190 /*
1191  * Check the scan cache for an ap/channel to use; if that
1192  * fails then kick off a new scan.
1193  */
1194 struct ieee80211_channel *
1195 ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
1196 {
1197         struct ieee80211_scan_state *ss = ic->ic_scan;
1198
1199         if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
1200                 /* XXX printf? */
1201                 return NULL;
1202         }
1203         if (ss->ss_ops->scan_pickchan == NULL) {
1204                 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
1205                     "%s: scan module does not support picking a channel, "
1206                     "opmode %d\n", __func__, ss->ss_vap->iv_opmode);
1207                 return NULL;
1208         }
1209         return ss->ss_ops->scan_pickchan(ss, flags);
1210 }