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         struct ieee80211com *ic = vap->iv_ic;
 445         const struct ieee80211_scanner *scan;
 446         int result;
 447
 448         ic = vap->iv_ic;
 449         scan = ieee80211_scanner_get(vap->iv_opmode);
 450         if (scan == NULL) {
 451                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 452                     "%s: no scanner support for %s mode\n",
 453                     __func__, ieee80211_opmode_name[vap->iv_opmode]);
 454                 /* XXX stat */
 455                 return 0;
 456         }
 457
 458         result = start_scan_locked(scan, vap, flags, duration,
 459             mindwell, maxdwell, nssid, ssids);
 460
 461         return result;
 462 }
 463
 464 /*
 465  * Check the scan cache for an ap/channel to use; if that
 466  * fails then kick off a new scan.
 467  */
 468 int
 469 ieee80211_check_scan(struct ieee80211vap *vap, int flags,
 470         u_int duration, u_int mindwell, u_int maxdwell,
 471         u_int nssid, const struct ieee80211_scan_ssid ssids[])
 472 {
 473         struct ieee80211com *ic = vap->iv_ic;
 474         struct ieee80211_scan_state *ss = ic->ic_scan;
 475         const struct ieee80211_scanner *scan;
 476         int result;
 477
 478         scan = ieee80211_scanner_get(vap->iv_opmode);
 479         if (scan == NULL) {
 480                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 481                     "%s: no scanner support for %d mode\n",
 482                     __func__, vap->iv_opmode);
 483                 /* XXX stat */
 484                 return 0;
 485         }
 486
 487         /*
 488          * Check if there's a list of scan candidates already.
 489          * XXX want more than the ap we're currently associated with
 490          */
 491
 492         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 493             "%s: %s scan, %s%s%s%s%s\n"
 494             , __func__
 495             , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
 496             , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
 497             , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
 498             , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
 499             , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
 500             , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
 501         );
 502
 503         if (ss->ss_ops != scan) {
 504                 /* XXX re-use cache contents? e.g. adhoc<->sta */
 505                 flags |= IEEE80211_SCAN_FLUSH;
 506         }
 507         scan_update_locked(vap, scan);
 508         if (ss->ss_ops != NULL) {
 509                 /* XXX verify ss_ops matches vap->iv_opmode */
 510                 if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
 511                         /*
 512                          * Update the ssid list and mark flags so if
 513                          * we call start_scan it doesn't duplicate work.
 514                          */
 515                         copy_ssid(vap, ss, nssid, ssids);
 516                         flags |= IEEE80211_SCAN_NOSSID;
 517                 }
 518                 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
 519                     (flags & IEEE80211_SCAN_FLUSH) == 0 &&
 520                     time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
 521                         /*
 522                          * We're not currently scanning and the cache is
 523                          * deemed hot enough to consult.  Lock out others
 524                          * by marking IEEE80211_F_SCAN while we decide if
 525                          * something is already in the scan cache we can
 526                          * use.  Also discard any frames that might come
 527                          * in while temporarily marked as scanning.
 528                          */
 529                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
 530                         ic->ic_flags |= IEEE80211_F_SCAN;
 531
 532                         /* NB: need to use supplied flags in check */
 533                         ss->ss_flags = flags & 0xff;
 534                         result = ss->ss_ops->scan_end(ss, vap);
 535
 536                         ic->ic_flags &= ~IEEE80211_F_SCAN;
 537                         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
 538                         if (result) {
 539                                 ieee80211_notify_scan_done(vap);
 540                                 return 1;
 541                         }
 542                 }
 543         }
 544         result = start_scan_locked(scan, vap, flags, duration,
 545             mindwell, maxdwell, nssid, ssids);
 546
 547         return result;
 548 }
 549
 550 /*
 551  * Check the scan cache for an ap/channel to use; if that fails
 552  * then kick off a scan using the current settings.
 553  */
 554 int
 555 ieee80211_check_scan_current(struct ieee80211vap *vap)
 556 {
 557         return ieee80211_check_scan(vap,
 558             IEEE80211_SCAN_ACTIVE,
 559             IEEE80211_SCAN_FOREVER, 0, 0,
 560             vap->iv_des_nssid, vap->iv_des_ssid);
 561 }
 562
 563 /*
 564  * Restart a previous scan.  If the previous scan completed
 565  * then we start again using the existing channel list.
 566  */
 567 int
 568 ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
 569 {
 570         struct ieee80211com *ic = vap->iv_ic;
 571         struct ieee80211_scan_state *ss = ic->ic_scan;
 572         const struct ieee80211_scanner *scan;
 573
 574         scan = ieee80211_scanner_get(vap->iv_opmode);
 575         if (scan == NULL) {
 576                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 577                     "%s: no scanner support for %d mode\n",
 578                     __func__, vap->iv_opmode);
 579                 /* XXX stat */
 580                 return 0;
 581         }
 582
 583         if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
 584                 u_int duration;
 585                 /*
 586                  * Go off-channel for a fixed interval that is large
 587                  * enough to catch most ap's but short enough that
 588                  * we can return on-channel before our listen interval
 589                  * expires.
 590                  */
 591                 duration = IEEE80211_SCAN_OFFCHANNEL;
 592
 593                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 594                     "%s: %s scan, ticks %u duration %u\n", __func__,
 595                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
 596                     ticks, duration);
 597
 598                 scan_update_locked(vap, scan);
 599                 if (ss->ss_ops != NULL) {
 600                         ss->ss_vap = vap;
 601                         /*
 602                          * A background scan does not select a new sta; it
 603                          * just refreshes the scan cache.  Also, indicate
 604                          * the scan logic should follow the beacon schedule:
 605                          * we go off-channel and scan for a while, then
 606                          * return to the bss channel to receive a beacon,
 607                          * then go off-channel again.  All during this time
 608                          * we notify the ap we're in power save mode.  When
 609                          * the scan is complete we leave power save mode.
 610                          * If any beacon indicates there are frames pending
 611                          * for us then we drop out of power save mode
 612                          * (and background scan) automatically by way of the
 613                          * usual sta power save logic.
 614                          */
 615                         ss->ss_flags |= IEEE80211_SCAN_NOPICK
 616                                      |  IEEE80211_SCAN_BGSCAN
 617                                      |  flags
 618                                      ;
 619                         /* if previous scan completed, restart */
 620                         if (ss->ss_next >= ss->ss_last) {
 621                                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 622                                         vap->iv_stats.is_scan_active++;
 623                                 else
 624                                         vap->iv_stats.is_scan_passive++;
 625                                 /*
 626                                  * NB: beware of the scan cache being flushed;
 627                                  *     if the channel list is empty use the
 628                                  *     scan_start method to populate it.
 629                                  */
 630                                 ss->ss_next = 0;
 631                                 if (ss->ss_last != 0)
 632                                         ss->ss_ops->scan_restart(ss, vap);
 633                                 else {
 634                                         ss->ss_ops->scan_start(ss, vap);
 635 #ifdef IEEE80211_DEBUG
 636                                         if (ieee80211_msg_scan(vap))
 637                                                 scan_dump(ss);
 638 #endif /* IEEE80211_DEBUG */
 639                                 }
 640                         }
 641                         /* NB: flush frames rx'd before 1st channel change */
 642                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
 643                         SCAN_PRIVATE(ss)->ss_duration = duration;
 644                         ss->ss_maxdwell = duration;
 645                         ic->ic_flags |= IEEE80211_F_SCAN;
 646                         ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
 647                         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 648                 } else {
 649                         /* XXX msg+stat */
 650                 }
 651         } else {
 652                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 653                     "%s: %s scan already in progress\n", __func__,
 654                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
 655         }
 656
 657         /* NB: racey, does it matter? */
 658         return (ic->ic_flags & IEEE80211_F_SCAN);
 659 }
 660
 661 /*
 662  * Cancel any scan currently going on for the specified vap.
 663  */
 664 void
 665 ieee80211_cancel_scan(struct ieee80211vap *vap)
 666 {
 667         struct ieee80211com *ic = vap->iv_ic;
 668         struct ieee80211_scan_state *ss = ic->ic_scan;
 669
 670         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
 671             ss->ss_vap == vap &&
 672             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
 673                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 674                     "%s: cancel %s scan\n", __func__,
 675                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
 676                         "active" : "passive");
 677
 678                 /* clear bg scan NOPICK and mark cancel request */
 679                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
 680                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
 681                 /* wake up the scan task */
 682                 scan_signal(ss);
 683         }
 684 }
 685
 686 /*
 687  * Cancel any scan currently going on.
 688  */
 689 void
 690 ieee80211_cancel_anyscan(struct ieee80211vap *vap)
 691 {
 692         struct ieee80211com *ic = vap->iv_ic;
 693         struct ieee80211_scan_state *ss = ic->ic_scan;
 694
 695         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
 696             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
 697                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 698                     "%s: cancel %s scan\n", __func__,
 699                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
 700                         "active" : "passive");
 701
 702                 /* clear bg scan NOPICK and mark cancel request */
 703                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
 704                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
 705                 /* wake up the scan task */
 706                 scan_signal(ss);
 707         }
 708 }
 709
 710 /*
 711  * Public access to scan_next for drivers that manage
 712  * scanning themselves (e.g. for firmware-based devices).
 713  */
 714 void
 715 ieee80211_scan_next(struct ieee80211vap *vap)
 716 {
 717         struct ieee80211com *ic = vap->iv_ic;
 718         struct ieee80211_scan_state *ss = ic->ic_scan;
 719
 720         /* wake up the scan task */
 721         scan_signal(ss);
 722 }
 723
 724 /*
 725  * Public access to scan_next for drivers that are not able to scan single
 726  * channels (e.g. for firmware-based devices).
 727  */
 728 void
 729 ieee80211_scan_done(struct ieee80211vap *vap)
 730 {
 731         struct ieee80211com *ic = vap->iv_ic;
 732         struct ieee80211_scan_state *ss;
 733
 734         ss = ic->ic_scan;
 735         ss->ss_next = ss->ss_last; /* all channels are complete */
 736         scan_signal(ss);
 737 }
 738
 739 /*
 740  * Probe the curent channel, if allowed, while scanning.
 741  * If the channel is not marked passive-only then send
 742  * a probe request immediately.  Otherwise mark state and
 743  * listen for beacons on the channel; if we receive something
 744  * then we'll transmit a probe request.
 745  */
 746 void
 747 ieee80211_probe_curchan(struct ieee80211vap *vap, int force)
 748 {
 749         struct ieee80211com *ic = vap->iv_ic;
 750         struct ieee80211_scan_state *ss = ic->ic_scan;
 751         struct ifnet *ifp = vap->iv_ifp;
 752         int i;
 753
 754         if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
 755                 ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
 756                 return;
 757         }
 758         /*
 759          * Send directed probe requests followed by any
 760          * broadcast probe request.
 761          * XXX remove dependence on ic/vap->iv_bss
 762          */
 763         for (i = 0; i < ss->ss_nssid; i++)
 764                 ieee80211_send_probereq(vap->iv_bss,
 765                         vap->iv_myaddr, ifp->if_broadcastaddr,
 766                         ifp->if_broadcastaddr,
 767                         ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
 768         if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
 769                 ieee80211_send_probereq(vap->iv_bss,
 770                         vap->iv_myaddr, ifp->if_broadcastaddr,
 771                         ifp->if_broadcastaddr,
 772                         "", 0);
 773 }
 774
 775 /*
 776  * Scan curchan.  If this is an active scan and the channel
 777  * is not marked passive then send probe request frame(s).
 778  * Arrange for the channel change after maxdwell ticks.
 779  */
 780 static void
 781 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
 782 {
 783         struct ieee80211vap *vap  = ss->ss_vap;
 784
 785         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 786                 ieee80211_probe_curchan(vap, 0);
 787         callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
 788                       maxdwell, scan_signal_callout, ss);
 789 }
 790
 791 static void
 792 scan_signal_callout(void *arg)
 793 {
 794         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
 795
 796         wlan_serialize_enter();
 797         scan_signal(ss);
 798         wlan_serialize_exit();
 799 }
 800
 801 static void
 802 scan_signal(struct ieee80211_scan_state *ss)
 803 {
 804         wlan_cv_signal(&SCAN_PRIVATE(ss)->ss_scan_cv, 0);
 805 }
 806
 807 /*
 808  * Handle mindwell requirements completed; initiate a channel
 809  * change to the next channel asap.
 810  */
 811 static void
 812 scan_mindwell(struct ieee80211_scan_state *ss)
 813 {
 814         struct ieee80211com *ic = ss->ss_ic;
 815
 816         ic = ss->ss_ic;
 817         scan_signal(ss);
 818 }
 819
 820 static void
 821 scan_task(void *arg, int pending)
 822 {
 823 #define ISCAN_REP       (ISCAN_MINDWELL | ISCAN_DISCARD)
 824         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
 825         struct ieee80211vap *vap;
 826         struct ieee80211com *ic;
 827         struct ieee80211_channel *chan;
 828         unsigned long maxdwell, scanend;
 829         int scandone = 0;
 830
 831         wlan_serialize_enter();
 832         vap = ss->ss_vap;
 833         ic = ss->ss_ic;
 834
 835         if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
 836             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
 837                 /* Cancelled before we started */
 838                 goto done;
 839         }
 840
 841         if (ss->ss_next == ss->ss_last) {
 842                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 843                         "%s: no channels to scan\n", __func__);
 844                 goto done;
 845         }
 846
 847         if (vap->iv_opmode == IEEE80211_M_STA &&
 848             vap->iv_state == IEEE80211_S_RUN) {
 849                 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
 850                         /* Enable station power save mode */
 851                         ieee80211_sta_pwrsave(vap, 1);
 852                         /*
 853                          * Use an 1ms delay so the null data frame has a chance
 854                          * to go out.  Minimum one tick.
 855                          * XXX Should use M_TXCB mechanism to eliminate this.
 856                          */
 857                         wlan_cv_timedwait(&SCAN_PRIVATE(ss)->ss_scan_cv,
 858                                           hz / 1000 + 1);
 859                         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
 860                                 goto done;
 861                 }
 862         }
 863
 864         scanend = ticks + SCAN_PRIVATE(ss)->ss_duration;
 865         ic->ic_scan_start(ic);          /* notify driver */
 866
 867         for (;;) {
 868                 scandone = (ss->ss_next >= ss->ss_last) ||
 869                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0;
 870                 if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
 871                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT) ||
 872                      time_after(ticks + ss->ss_mindwell, scanend))
 873                         break;
 874
 875                 chan = ss->ss_chans[ss->ss_next++];
 876
 877                 /*
 878                  * Watch for truncation due to the scan end time.
 879                  */
 880                 if (time_after(ticks + ss->ss_maxdwell, scanend))
 881                         maxdwell = scanend - ticks;
 882                 else
 883                         maxdwell = ss->ss_maxdwell;
 884
 885                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 886                     "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
 887                     __func__,
 888                     ieee80211_chan2ieee(ic, ic->ic_curchan),
 889                         channel_type(ic->ic_curchan),
 890                     ieee80211_chan2ieee(ic, chan), channel_type(chan),
 891                     (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
 892                         (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
 893                         "active" : "passive",
 894                     ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
 895
 896                 /*
 897                  * Potentially change channel and phy mode.
 898                  */
 899                 ic->ic_curchan = chan;
 900                 ic->ic_rt = ieee80211_get_ratetable(chan);
 901                 /*
 902                  * Perform the channel change and scan unlocked so the driver
 903                  * may sleep. Once set_channel returns the hardware has
 904                  * completed the channel change.
 905                  */
 906                 ic->ic_set_channel(ic);
 907                 ieee80211_radiotap_chan_change(ic);
 908
 909                 /*
 910                  * Scan curchan.  Drivers for "intelligent hardware"
 911                  * override ic_scan_curchan to tell the device to do
 912                  * the work.  Otherwise we manage the work outselves;
 913                  * sending a probe request (as needed), and arming the
 914                  * timeout to switch channels after maxdwell ticks.
 915                  *
 916                  * scan_curchan should only pause for the time required to
 917                  * prepare/initiate the hardware for the scan (if at all), the
 918                  * below condvar is used to sleep for the channels dwell time
 919                  * and allows it to be signalled for abort.
 920                  */
 921                 ic->ic_scan_curchan(ss, maxdwell);
 922
 923                 SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell;
 924                 /* clear mindwell lock and initial channel change flush */
 925                 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
 926
 927                 if ((SCAN_PRIVATE(ss)->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)))
 928                         continue;
 929
 930                 /* Wait to be signalled to scan the next channel */
 931                 wlan_cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv);
 932         }
 933         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
 934                 goto done;
 935
 936         ic->ic_scan_end(ic);            /* notify driver */
 937
 938         /*
 939          * Record scan complete time.  Note that we also do
 940          * this when canceled so any background scan will
 941          * not be restarted for a while.
 942          */
 943         if (scandone)
 944                 ic->ic_lastscan = ticks;
 945         /* return to the bss channel */
 946         if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
 947             ic->ic_curchan != ic->ic_bsschan) {
 948                 ieee80211_setupcurchan(ic, ic->ic_bsschan);
 949                 ic->ic_set_channel(ic);
 950                 ieee80211_radiotap_chan_change(ic);
 951         }
 952         /* clear internal flags and any indication of a pick */
 953         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
 954         ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
 955
 956         /*
 957          * If not canceled and scan completed, do post-processing.
 958          * If the callback function returns 0, then it wants to
 959          * continue/restart scanning.  Unfortunately we needed to
 960          * notify the driver to end the scan above to avoid having
 961          * rx frames alter the scan candidate list.
 962          */
 963         if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 &&
 964             !ss->ss_ops->scan_end(ss, vap) &&
 965             (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
 966             time_before(ticks + ss->ss_mindwell, scanend)) {
 967                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 968                     "%s: done, restart "
 969                     "[ticks %u, dwell min %lu scanend %lu]\n",
 970                     __func__,
 971                     ticks, ss->ss_mindwell, scanend);
 972                 ss->ss_next = 0;        /* reset to begining */
 973                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
 974                         vap->iv_stats.is_scan_active++;
 975                 else
 976                         vap->iv_stats.is_scan_passive++;
 977
 978                 ss->ss_ops->scan_restart(ss, vap);      /* XXX? */
 979                 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 980                 goto done2;
 981         }
 982
 983         /* past here, scandone is ``true'' if not in bg mode */
 984         if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
 985                 scandone = 1;
 986
 987         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 988             "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
 989             __func__, scandone ? "done" : "stopped",
 990             ticks, ss->ss_mindwell, scanend);
 991
 992         /*
 993          * Clear the SCAN bit first in case frames are
 994          * pending on the station power save queue.  If
 995          * we defer this then the dispatch of the frames
 996          * may generate a request to cancel scanning.
 997          */
 998 done:
 999         ic->ic_flags &= ~IEEE80211_F_SCAN;
1000         /*
1001          * Drop out of power save mode when a scan has
1002          * completed.  If this scan was prematurely terminated
1003          * because it is a background scan then don't notify
1004          * the ap; we'll either return to scanning after we
1005          * receive the beacon frame or we'll drop out of power
1006          * save mode because the beacon indicates we have frames
1007          * waiting for us.
1008          */
1009         if (scandone) {
1010                 ieee80211_sta_pwrsave(vap, 0);
1011                 if (ss->ss_next >= ss->ss_last) {
1012                         ieee80211_notify_scan_done(vap);
1013                         ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
1014                 }
1015         }
1016         SCAN_PRIVATE(ss)->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
1017         ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
1018 done2:
1019         wlan_serialize_exit();
1020 #undef ISCAN_REP
1021 }
1022
1023 #ifdef IEEE80211_DEBUG
1024 static void
1025 dump_country(const uint8_t *ie)
1026 {
1027         const struct ieee80211_country_ie *cie =
1028            (const struct ieee80211_country_ie *) ie;
1029         int i, nbands, schan, nchan;
1030
1031         if (cie->len < 3) {
1032                 kprintf(" <bogus country ie, len %d>", cie->len);
1033                 return;
1034         }
1035         kprintf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]);
1036         nbands = (cie->len - 3) / sizeof(cie->band[0]);
1037         for (i = 0; i < nbands; i++) {
1038                 schan = cie->band[i].schan;
1039                 nchan = cie->band[i].nchan;
1040                 if (nchan != 1)
1041                         kprintf(" %u-%u,%u", schan, schan + nchan-1,
1042                             cie->band[i].maxtxpwr);
1043                 else
1044                         kprintf(" %u,%u", schan, cie->band[i].maxtxpwr);
1045         }
1046         kprintf("]");
1047 }
1048
1049 static void
1050 dump_probe_beacon(uint8_t subtype, int isnew,
1051         const uint8_t mac[IEEE80211_ADDR_LEN],
1052         const struct ieee80211_scanparams *sp, int rssi)
1053 {
1054
1055         kprintf("[%6D] %s%s on chan %u (bss chan %u) ",
1056             mac, ":", isnew ? "new " : "",
1057             ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT],
1058             sp->chan, sp->bchan);
1059         ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
1060         kprintf(" rssi %d\n", rssi);
1061
1062         if (isnew) {
1063                 kprintf("[%6D] caps 0x%x bintval %u erp 0x%x",
1064                         mac, ":", sp->capinfo, sp->bintval, sp->erp);
1065                 if (sp->country != NULL)
1066                         dump_country(sp->country);
1067                 kprintf("\n");
1068         }
1069 }
1070 #endif /* IEEE80211_DEBUG */
1071
1072 /*
1073  * Process a beacon or probe response frame.
1074  */
1075 void
1076 ieee80211_add_scan(struct ieee80211vap *vap,
1077         const struct ieee80211_scanparams *sp,
1078         const struct ieee80211_frame *wh,
1079         int subtype, int rssi, int noise)
1080 {
1081         struct ieee80211com *ic = vap->iv_ic;
1082         struct ieee80211_scan_state *ss = ic->ic_scan;
1083
1084         /* XXX locking */
1085         /*
1086          * Frames received during startup are discarded to avoid
1087          * using scan state setup on the initial entry to the timer
1088          * callback.  This can occur because the device may enable
1089          * rx prior to our doing the initial channel change in the
1090          * timer routine.
1091          */
1092         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
1093                 return;
1094 #ifdef IEEE80211_DEBUG
1095         if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
1096                 dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
1097 #endif
1098         if (ss->ss_ops != NULL &&
1099             ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise)) {
1100                 /*
1101                  * If we've reached the min dwell time terminate
1102                  * the timer so we'll switch to the next channel.
1103                  */
1104                 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
1105                     time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
1106                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
1107                             "%s: chan %3d%c min dwell met (%u > %lu)\n",
1108                             __func__,
1109                             ieee80211_chan2ieee(ic, ic->ic_curchan),
1110                                 channel_type(ic->ic_curchan),
1111                             ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
1112                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
1113                         /*
1114                          * NB: trigger at next clock tick or wait for the
1115                          * hardware.
1116                          */
1117                         ic->ic_scan_mindwell(ss);
1118                 }
1119         }
1120 }
1121
1122 /*
1123  * Timeout/age scan cache entries; called from sta timeout
1124  * timer (XXX should be self-contained).
1125  */
1126 void
1127 ieee80211_scan_timeout(struct ieee80211com *ic)
1128 {
1129         struct ieee80211_scan_state *ss = ic->ic_scan;
1130
1131         if (ss->ss_ops != NULL)
1132                 ss->ss_ops->scan_age(ss);
1133 }
1134
1135 /*
1136  * Mark a scan cache entry after a successful associate.
1137  */
1138 void
1139 ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
1140 {
1141         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1142
1143         if (ss->ss_ops != NULL) {
1144                 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN,
1145                         mac, "%s",  __func__);
1146                 ss->ss_ops->scan_assoc_success(ss, mac);
1147         }
1148 }
1149
1150 /*
1151  * Demerit a scan cache entry after failing to associate.
1152  */
1153 void
1154 ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
1155         const uint8_t mac[], int reason)
1156 {
1157         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1158
1159         if (ss->ss_ops != NULL) {
1160                 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac,
1161                         "%s: reason %u", __func__, reason);
1162                 ss->ss_ops->scan_assoc_fail(ss, mac, reason);
1163         }
1164 }
1165
1166 /*
1167  * Iterate over the contents of the scan cache.
1168  */
1169 void
1170 ieee80211_scan_iterate(struct ieee80211vap *vap,
1171         ieee80211_scan_iter_func *f, void *arg)
1172 {
1173         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1174
1175         if (ss->ss_ops != NULL)
1176                 ss->ss_ops->scan_iterate(ss, f, arg);
1177 }
1178
1179 /*
1180  * Flush the contents of the scan cache.
1181  */
1182 void
1183 ieee80211_scan_flush(struct ieee80211vap *vap)
1184 {
1185         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
1186
1187         if (ss->ss_ops != NULL && ss->ss_vap == vap) {
1188                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n",  __func__);
1189                 ss->ss_ops->scan_flush(ss);
1190         }
1191 }
1192
1193 /*
1194  * Check the scan cache for an ap/channel to use; if that
1195  * fails then kick off a new scan.
1196  */
1197 struct ieee80211_channel *
1198 ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
1199 {
1200         struct ieee80211_scan_state *ss = ic->ic_scan;
1201
1202         if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
1203                 /* XXX printf? */
1204                 return NULL;
1205         }
1206         if (ss->ss_ops->scan_pickchan == NULL) {
1207                 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
1208                     "%s: scan module does not support picking a channel, "
1209                     "opmode %d\n", __func__, ss->ss_vap->iv_opmode);
1210                 return NULL;
1211         }
1212         return ss->ss_ops->scan_pickchan(ss, flags);
1213 }