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FreeBSD/Linux Kernel Cross Reference
sys/net80211/ieee80211_scan.c

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    1 /*-
    2  * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   24  */
   25 
   26 #include <sys/cdefs.h>
   27 __FBSDID("$FreeBSD: releng/8.1/sys/net80211/ieee80211_scan.c 199583 2009-11-20 15:27:52Z jhb $");
   28 
   29 /*
   30  * IEEE 802.11 scanning support.
   31  */
   32 #include "opt_wlan.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h> 
   36 #include <sys/proc.h>
   37 #include <sys/kernel.h>
   38 #include <sys/condvar.h>
   39  
   40 #include <sys/socket.h>
   41 
   42 #include <net/if.h>
   43 #include <net/if_media.h>
   44 #include <net/ethernet.h>
   45 
   46 #include <net80211/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(void *);
   98 static  void scan_task(void *, int);
   99 
  100 MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
  101 
  102 void
  103 ieee80211_scan_attach(struct ieee80211com *ic)
  104 {
  105         struct scan_state *ss;
  106 
  107         ss = (struct scan_state *) malloc(sizeof(struct scan_state),
  108                 M_80211_SCAN, M_NOWAIT | M_ZERO);
  109         if (ss == NULL) {
  110                 ic->ic_scan = NULL;
  111                 return;
  112         }
  113         callout_init_mtx(&ss->ss_scan_timer, IEEE80211_LOCK_OBJ(ic), 0);
  114         cv_init(&ss->ss_scan_cv, "scan");
  115         TASK_INIT(&ss->ss_scan_task, 0, scan_task, ss);
  116         ic->ic_scan = &ss->base;
  117         ss->base.ss_ic = ic;
  118 
  119         ic->ic_scan_curchan = scan_curchan;
  120         ic->ic_scan_mindwell = scan_mindwell;
  121 }
  122 
  123 void
  124 ieee80211_scan_detach(struct ieee80211com *ic)
  125 {
  126         struct ieee80211_scan_state *ss = ic->ic_scan;
  127 
  128         if (ss != NULL) {
  129                 IEEE80211_LOCK(ic);
  130                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
  131                 scan_signal(ss);
  132                 IEEE80211_UNLOCK(ic);
  133                 ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
  134                 callout_drain(&SCAN_PRIVATE(ss)->ss_scan_timer);
  135                 KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0,
  136                     ("scan still running"));
  137                 if (ss->ss_ops != NULL) {
  138                         ss->ss_ops->scan_detach(ss);
  139                         ss->ss_ops = NULL;
  140                 }
  141                 ic->ic_scan = NULL;
  142                 free(SCAN_PRIVATE(ss), M_80211_SCAN);
  143         }
  144 }
  145 
  146 static const struct ieee80211_roamparam defroam[IEEE80211_MODE_MAX] = {
  147         [IEEE80211_MODE_11A]    = { .rssi = ROAM_RSSI_11A_DEFAULT,
  148                                     .rate = ROAM_RATE_11A_DEFAULT },
  149         [IEEE80211_MODE_11G]    = { .rssi = ROAM_RSSI_11B_DEFAULT,
  150                                     .rate = ROAM_RATE_11B_DEFAULT },
  151         [IEEE80211_MODE_11B]    = { .rssi = ROAM_RSSI_11BONLY_DEFAULT,
  152                                     .rate = ROAM_RATE_11BONLY_DEFAULT },
  153         [IEEE80211_MODE_TURBO_A]= { .rssi = ROAM_RSSI_11A_DEFAULT,
  154                                     .rate = ROAM_RATE_11A_DEFAULT },
  155         [IEEE80211_MODE_TURBO_G]= { .rssi = ROAM_RSSI_11A_DEFAULT,
  156                                     .rate = ROAM_RATE_11A_DEFAULT },
  157         [IEEE80211_MODE_STURBO_A]={ .rssi = ROAM_RSSI_11A_DEFAULT,
  158                                     .rate = ROAM_RATE_11A_DEFAULT },
  159         [IEEE80211_MODE_HALF]   = { .rssi = ROAM_RSSI_11A_DEFAULT,
  160                                     .rate = ROAM_RATE_HALF_DEFAULT },
  161         [IEEE80211_MODE_QUARTER]= { .rssi = ROAM_RSSI_11A_DEFAULT,
  162                                     .rate = ROAM_RATE_QUARTER_DEFAULT },
  163         [IEEE80211_MODE_11NA]   = { .rssi = ROAM_RSSI_11A_DEFAULT,
  164                                     .rate = ROAM_MCS_11N_DEFAULT },
  165         [IEEE80211_MODE_11NG]   = { .rssi = ROAM_RSSI_11B_DEFAULT,
  166                                     .rate = ROAM_MCS_11N_DEFAULT },
  167 };
  168 
  169 void
  170 ieee80211_scan_vattach(struct ieee80211vap *vap)
  171 {
  172         vap->iv_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz;
  173         vap->iv_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz;
  174         vap->iv_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz;
  175 
  176         vap->iv_roaming = IEEE80211_ROAMING_AUTO;
  177         memcpy(vap->iv_roamparms, defroam, sizeof(defroam));
  178 }
  179 
  180 void
  181 ieee80211_scan_vdetach(struct ieee80211vap *vap)
  182 {
  183         struct ieee80211com *ic = vap->iv_ic;
  184         struct ieee80211_scan_state *ss;
  185 
  186         IEEE80211_LOCK(ic);
  187         ss = ic->ic_scan;
  188         if (ss != NULL && ss->ss_vap == vap) {
  189                 if (ic->ic_flags & IEEE80211_F_SCAN) {
  190                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
  191                         scan_signal(ss);
  192                 }
  193                 if (ss->ss_ops != NULL) {
  194                         ss->ss_ops->scan_detach(ss);
  195                         ss->ss_ops = NULL;
  196                 }
  197                 ss->ss_vap = NULL;
  198         }
  199         IEEE80211_UNLOCK(ic);
  200 }
  201 
  202 /*
  203  * Simple-minded scanner module support.
  204  */
  205 static const char *scan_modnames[IEEE80211_OPMODE_MAX] = {
  206         "wlan_scan_sta",        /* IEEE80211_M_IBSS */
  207         "wlan_scan_sta",        /* IEEE80211_M_STA */
  208         "wlan_scan_wds",        /* IEEE80211_M_WDS */
  209         "wlan_scan_sta",        /* IEEE80211_M_AHDEMO */
  210         "wlan_scan_ap",         /* IEEE80211_M_HOSTAP */
  211         "wlan_scan_monitor",    /* IEEE80211_M_MONITOR */
  212         "wlan_scan_sta",        /* IEEE80211_M_MBSS */
  213 };
  214 static const struct ieee80211_scanner *scanners[IEEE80211_OPMODE_MAX];
  215 
  216 const struct ieee80211_scanner *
  217 ieee80211_scanner_get(enum ieee80211_opmode mode)
  218 {
  219         if (mode >= IEEE80211_OPMODE_MAX)
  220                 return NULL;
  221         if (scanners[mode] == NULL)
  222                 ieee80211_load_module(scan_modnames[mode]);
  223         return scanners[mode];
  224 }
  225 
  226 void
  227 ieee80211_scanner_register(enum ieee80211_opmode mode,
  228         const struct ieee80211_scanner *scan)
  229 {
  230         if (mode >= IEEE80211_OPMODE_MAX)
  231                 return;
  232         scanners[mode] = scan;
  233 }
  234 
  235 void
  236 ieee80211_scanner_unregister(enum ieee80211_opmode mode,
  237         const struct ieee80211_scanner *scan)
  238 {
  239         if (mode >= IEEE80211_OPMODE_MAX)
  240                 return;
  241         if (scanners[mode] == scan)
  242                 scanners[mode] = NULL;
  243 }
  244 
  245 void
  246 ieee80211_scanner_unregister_all(const struct ieee80211_scanner *scan)
  247 {
  248         int m;
  249 
  250         for (m = 0; m < IEEE80211_OPMODE_MAX; m++)
  251                 if (scanners[m] == scan)
  252                         scanners[m] = NULL;
  253 }
  254 
  255 /*
  256  * Update common scanner state to reflect the current
  257  * operating mode.  This is called when the state machine
  258  * is transitioned to RUN state w/o scanning--e.g. when
  259  * operating in monitor mode.  The purpose of this is to
  260  * ensure later callbacks find ss_ops set to properly
  261  * reflect current operating mode.
  262  */
  263 static void
  264 scan_update_locked(struct ieee80211vap *vap,
  265         const struct ieee80211_scanner *scan)
  266 {
  267         struct ieee80211com *ic = vap->iv_ic;
  268         struct ieee80211_scan_state *ss = ic->ic_scan;
  269 
  270         IEEE80211_LOCK_ASSERT(ic);
  271 
  272 #ifdef IEEE80211_DEBUG
  273         if (ss->ss_vap != vap || ss->ss_ops != scan) {
  274                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  275                     "%s: current scanner is <%s:%s>, switch to <%s:%s>\n",
  276                     __func__,
  277                     ss->ss_vap != NULL ?
  278                         ss->ss_vap->iv_ifp->if_xname : "none",
  279                     ss->ss_vap != NULL ?
  280                         ieee80211_opmode_name[ss->ss_vap->iv_opmode] : "none",
  281                     vap->iv_ifp->if_xname,
  282                     ieee80211_opmode_name[vap->iv_opmode]);
  283         }
  284 #endif
  285         ss->ss_vap = vap;
  286         if (ss->ss_ops != scan) {
  287                 /*
  288                  * Switch scanners; detach old, attach new.  Special
  289                  * case where a single scan module implements multiple
  290                  * policies by using different scan ops but a common
  291                  * core.  We assume if the old and new attach methods
  292                  * are identical then it's ok to just change ss_ops
  293                  * and not flush the internal state of the module.
  294                  */
  295                 if (scan == NULL || ss->ss_ops == NULL ||
  296                     ss->ss_ops->scan_attach != scan->scan_attach) {
  297                         if (ss->ss_ops != NULL)
  298                                 ss->ss_ops->scan_detach(ss);
  299                         if (scan != NULL && !scan->scan_attach(ss)) {
  300                                 /* XXX attach failure */
  301                                 /* XXX stat+msg */
  302                                 scan = NULL;
  303                         }
  304                 }
  305                 ss->ss_ops = scan;
  306         }
  307 }
  308 
  309 static char
  310 channel_type(const struct ieee80211_channel *c)
  311 {
  312         if (IEEE80211_IS_CHAN_ST(c))
  313                 return 'S';
  314         if (IEEE80211_IS_CHAN_108A(c))
  315                 return 'T';
  316         if (IEEE80211_IS_CHAN_108G(c))
  317                 return 'G';
  318         if (IEEE80211_IS_CHAN_HT(c))
  319                 return 'n';
  320         if (IEEE80211_IS_CHAN_A(c))
  321                 return 'a';
  322         if (IEEE80211_IS_CHAN_ANYG(c))
  323                 return 'g';
  324         if (IEEE80211_IS_CHAN_B(c))
  325                 return 'b';
  326         return 'f';
  327 }
  328 
  329 void
  330 ieee80211_scan_dump_channels(const struct ieee80211_scan_state *ss)
  331 {
  332         struct ieee80211com *ic = ss->ss_ic;
  333         const char *sep;
  334         int i;
  335 
  336         sep = "";
  337         for (i = ss->ss_next; i < ss->ss_last; i++) {
  338                 const struct ieee80211_channel *c = ss->ss_chans[i];
  339 
  340                 printf("%s%u%c", sep, ieee80211_chan2ieee(ic, c),
  341                         channel_type(c));
  342                 sep = ", ";
  343         }
  344 }
  345 
  346 #ifdef IEEE80211_DEBUG
  347 static void
  348 scan_dump(struct ieee80211_scan_state *ss)
  349 {
  350         struct ieee80211vap *vap = ss->ss_vap;
  351 
  352         if_printf(vap->iv_ifp, "scan set ");
  353         ieee80211_scan_dump_channels(ss);
  354         printf(" dwell min %lums max %lums\n",
  355             ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(ss->ss_maxdwell));
  356 }
  357 #endif /* IEEE80211_DEBUG */
  358 
  359 static void
  360 copy_ssid(struct ieee80211vap *vap, struct ieee80211_scan_state *ss,
  361         int nssid, const struct ieee80211_scan_ssid ssids[])
  362 {
  363         if (nssid > IEEE80211_SCAN_MAX_SSID) {
  364                 /* XXX printf */
  365                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  366                     "%s: too many ssid %d, ignoring all of them\n",
  367                     __func__, nssid);
  368                 return;
  369         }
  370         memcpy(ss->ss_ssid, ssids, nssid * sizeof(ssids[0]));
  371         ss->ss_nssid = nssid;
  372 }
  373 
  374 /*
  375  * Start a scan unless one is already going.
  376  */
  377 static int
  378 start_scan_locked(const struct ieee80211_scanner *scan,
  379         struct ieee80211vap *vap, int flags, u_int duration,
  380         u_int mindwell, u_int maxdwell,
  381         u_int nssid, const struct ieee80211_scan_ssid ssids[])
  382 {
  383         struct ieee80211com *ic = vap->iv_ic;
  384         struct ieee80211_scan_state *ss = ic->ic_scan;
  385 
  386         IEEE80211_LOCK_ASSERT(ic);
  387 
  388         if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
  389                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  390                     "%s: scan inhibited by pending channel change\n", __func__);
  391         } else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
  392                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  393                     "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
  394                     , __func__
  395                     , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
  396                     , duration, mindwell, maxdwell
  397                     , ieee80211_phymode_name[vap->iv_des_mode]
  398                     , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
  399                     , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
  400                     , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
  401                     , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
  402                     , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
  403                     , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
  404                 );
  405 
  406                 scan_update_locked(vap, scan);
  407                 if (ss->ss_ops != NULL) {
  408                         if ((flags & IEEE80211_SCAN_NOSSID) == 0)
  409                                 copy_ssid(vap, ss, nssid, ssids);
  410 
  411                         /* NB: top 4 bits for internal use */
  412                         ss->ss_flags = flags & 0xfff;
  413                         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
  414                                 vap->iv_stats.is_scan_active++;
  415                         else
  416                                 vap->iv_stats.is_scan_passive++;
  417                         if (flags & IEEE80211_SCAN_FLUSH)
  418                                 ss->ss_ops->scan_flush(ss);
  419 
  420                         /* NB: flush frames rx'd before 1st channel change */
  421                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
  422                         SCAN_PRIVATE(ss)->ss_duration = duration;
  423                         ss->ss_next = 0;
  424                         ss->ss_mindwell = mindwell;
  425                         ss->ss_maxdwell = maxdwell;
  426                         /* NB: scan_start must be before the scan runtask */
  427                         ss->ss_ops->scan_start(ss, vap);
  428 #ifdef IEEE80211_DEBUG
  429                         if (ieee80211_msg_scan(vap))
  430                                 scan_dump(ss);
  431 #endif /* IEEE80211_DEBUG */
  432                         ic->ic_flags |= IEEE80211_F_SCAN;
  433                         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
  434                 }
  435         } else {
  436                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  437                     "%s: %s scan already in progress\n", __func__,
  438                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
  439         }
  440         return (ic->ic_flags & IEEE80211_F_SCAN);
  441 }
  442 
  443 /*
  444  * Start a scan unless one is already going.
  445  */
  446 int
  447 ieee80211_start_scan(struct ieee80211vap *vap, int flags,
  448         u_int duration, u_int mindwell, u_int maxdwell,
  449         u_int nssid, const struct ieee80211_scan_ssid ssids[])
  450 {
  451         struct ieee80211com *ic = vap->iv_ic;
  452         const struct ieee80211_scanner *scan;
  453         int result;
  454 
  455         scan = ieee80211_scanner_get(vap->iv_opmode);
  456         if (scan == NULL) {
  457                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  458                     "%s: no scanner support for %s mode\n",
  459                     __func__, ieee80211_opmode_name[vap->iv_opmode]);
  460                 /* XXX stat */
  461                 return 0;
  462         }
  463 
  464         IEEE80211_LOCK(ic);
  465         result = start_scan_locked(scan, vap, flags, duration,
  466             mindwell, maxdwell, nssid, ssids);
  467         IEEE80211_UNLOCK(ic);
  468 
  469         return result;
  470 }
  471 
  472 /*
  473  * Check the scan cache for an ap/channel to use; if that
  474  * fails then kick off a new scan.
  475  */
  476 int
  477 ieee80211_check_scan(struct ieee80211vap *vap, int flags,
  478         u_int duration, u_int mindwell, u_int maxdwell,
  479         u_int nssid, const struct ieee80211_scan_ssid ssids[])
  480 {
  481         struct ieee80211com *ic = vap->iv_ic;
  482         struct ieee80211_scan_state *ss = ic->ic_scan;
  483         const struct ieee80211_scanner *scan;
  484         int result;
  485 
  486         scan = ieee80211_scanner_get(vap->iv_opmode);
  487         if (scan == NULL) {
  488                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  489                     "%s: no scanner support for %s mode\n",
  490                     __func__, vap->iv_opmode);
  491                 /* XXX stat */
  492                 return 0;
  493         }
  494 
  495         /*
  496          * Check if there's a list of scan candidates already.
  497          * XXX want more than the ap we're currently associated with
  498          */
  499 
  500         IEEE80211_LOCK(ic);
  501         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  502             "%s: %s scan, %s%s%s%s%s\n"
  503             , __func__
  504             , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
  505             , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
  506             , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
  507             , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
  508             , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
  509             , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
  510         );
  511 
  512         if (ss->ss_ops != scan) {
  513                 /* XXX re-use cache contents? e.g. adhoc<->sta */
  514                 flags |= IEEE80211_SCAN_FLUSH;
  515         }
  516         scan_update_locked(vap, scan);
  517         if (ss->ss_ops != NULL) {
  518                 /* XXX verify ss_ops matches vap->iv_opmode */
  519                 if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
  520                         /*
  521                          * Update the ssid list and mark flags so if
  522                          * we call start_scan it doesn't duplicate work.
  523                          */
  524                         copy_ssid(vap, ss, nssid, ssids);
  525                         flags |= IEEE80211_SCAN_NOSSID;
  526                 }
  527                 if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
  528                     (flags & IEEE80211_SCAN_FLUSH) == 0 &&
  529                     time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
  530                         /*
  531                          * We're not currently scanning and the cache is
  532                          * deemed hot enough to consult.  Lock out others
  533                          * by marking IEEE80211_F_SCAN while we decide if
  534                          * something is already in the scan cache we can
  535                          * use.  Also discard any frames that might come
  536                          * in while temporarily marked as scanning.
  537                          */
  538                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
  539                         ic->ic_flags |= IEEE80211_F_SCAN;
  540 
  541                         /* NB: need to use supplied flags in check */
  542                         ss->ss_flags = flags & 0xff;
  543                         result = ss->ss_ops->scan_end(ss, vap);
  544 
  545                         ic->ic_flags &= ~IEEE80211_F_SCAN;
  546                         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
  547                         if (result) {
  548                                 ieee80211_notify_scan_done(vap);
  549                                 IEEE80211_UNLOCK(ic);
  550                                 return 1;
  551                         }
  552                 }
  553         }
  554         result = start_scan_locked(scan, vap, flags, duration,
  555             mindwell, maxdwell, nssid, ssids);
  556         IEEE80211_UNLOCK(ic);
  557 
  558         return result;
  559 }
  560 
  561 /*
  562  * Check the scan cache for an ap/channel to use; if that fails
  563  * then kick off a scan using the current settings.
  564  */
  565 int
  566 ieee80211_check_scan_current(struct ieee80211vap *vap)
  567 {
  568         return ieee80211_check_scan(vap,
  569             IEEE80211_SCAN_ACTIVE,
  570             IEEE80211_SCAN_FOREVER, 0, 0,
  571             vap->iv_des_nssid, vap->iv_des_ssid);
  572 }
  573 
  574 /*
  575  * Restart a previous scan.  If the previous scan completed
  576  * then we start again using the existing channel list.
  577  */
  578 int
  579 ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
  580 {
  581         struct ieee80211com *ic = vap->iv_ic;
  582         struct ieee80211_scan_state *ss = ic->ic_scan;
  583         const struct ieee80211_scanner *scan;
  584 
  585         scan = ieee80211_scanner_get(vap->iv_opmode);
  586         if (scan == NULL) {
  587                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  588                     "%s: no scanner support for %s mode\n",
  589                     __func__, vap->iv_opmode);
  590                 /* XXX stat */
  591                 return 0;
  592         }
  593 
  594         IEEE80211_LOCK(ic);
  595         if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
  596                 u_int duration;
  597                 /*
  598                  * Go off-channel for a fixed interval that is large
  599                  * enough to catch most ap's but short enough that
  600                  * we can return on-channel before our listen interval
  601                  * expires.
  602                  */
  603                 duration = IEEE80211_SCAN_OFFCHANNEL;
  604 
  605                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  606                     "%s: %s scan, ticks %u duration %lu\n", __func__,
  607                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
  608                     ticks, duration);
  609 
  610                 scan_update_locked(vap, scan);
  611                 if (ss->ss_ops != NULL) {
  612                         ss->ss_vap = vap;
  613                         /*
  614                          * A background scan does not select a new sta; it
  615                          * just refreshes the scan cache.  Also, indicate
  616                          * the scan logic should follow the beacon schedule:
  617                          * we go off-channel and scan for a while, then
  618                          * return to the bss channel to receive a beacon,
  619                          * then go off-channel again.  All during this time
  620                          * we notify the ap we're in power save mode.  When
  621                          * the scan is complete we leave power save mode.
  622                          * If any beacon indicates there are frames pending
  623                          * for us then we drop out of power save mode
  624                          * (and background scan) automatically by way of the
  625                          * usual sta power save logic.
  626                          */
  627                         ss->ss_flags |= IEEE80211_SCAN_NOPICK
  628                                      |  IEEE80211_SCAN_BGSCAN
  629                                      |  flags
  630                                      ;
  631                         /* if previous scan completed, restart */
  632                         if (ss->ss_next >= ss->ss_last) {
  633                                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
  634                                         vap->iv_stats.is_scan_active++;
  635                                 else
  636                                         vap->iv_stats.is_scan_passive++;
  637                                 /*
  638                                  * NB: beware of the scan cache being flushed;
  639                                  *     if the channel list is empty use the
  640                                  *     scan_start method to populate it.
  641                                  */
  642                                 ss->ss_next = 0;
  643                                 if (ss->ss_last != 0)
  644                                         ss->ss_ops->scan_restart(ss, vap);
  645                                 else {
  646                                         ss->ss_ops->scan_start(ss, vap);
  647 #ifdef IEEE80211_DEBUG
  648                                         if (ieee80211_msg_scan(vap))
  649                                                 scan_dump(ss);
  650 #endif /* IEEE80211_DEBUG */
  651                                 }
  652                         }
  653                         /* NB: flush frames rx'd before 1st channel change */
  654                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
  655                         SCAN_PRIVATE(ss)->ss_duration = duration;
  656                         ss->ss_maxdwell = duration;
  657                         ic->ic_flags |= IEEE80211_F_SCAN;
  658                         ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
  659                         ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
  660                 } else {
  661                         /* XXX msg+stat */
  662                 }
  663         } else {
  664                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  665                     "%s: %s scan already in progress\n", __func__,
  666                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
  667         }
  668         IEEE80211_UNLOCK(ic);
  669 
  670         /* NB: racey, does it matter? */
  671         return (ic->ic_flags & IEEE80211_F_SCAN);
  672 }
  673 
  674 /*
  675  * Cancel any scan currently going on for the specified vap.
  676  */
  677 void
  678 ieee80211_cancel_scan(struct ieee80211vap *vap)
  679 {
  680         struct ieee80211com *ic = vap->iv_ic;
  681         struct ieee80211_scan_state *ss = ic->ic_scan;
  682 
  683         IEEE80211_LOCK(ic);
  684         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
  685             ss->ss_vap == vap &&
  686             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
  687                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  688                     "%s: cancel %s scan\n", __func__,
  689                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
  690                         "active" : "passive");
  691 
  692                 /* clear bg scan NOPICK and mark cancel request */
  693                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
  694                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
  695                 /* wake up the scan task */
  696                 scan_signal(ss);
  697         }
  698         IEEE80211_UNLOCK(ic);
  699 }
  700 
  701 /*
  702  * Cancel any scan currently going on.
  703  */
  704 void
  705 ieee80211_cancel_anyscan(struct ieee80211vap *vap)
  706 {
  707         struct ieee80211com *ic = vap->iv_ic;
  708         struct ieee80211_scan_state *ss = ic->ic_scan;
  709 
  710         IEEE80211_LOCK(ic);
  711         if ((ic->ic_flags & IEEE80211_F_SCAN) &&
  712             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
  713                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  714                     "%s: cancel %s scan\n", __func__,
  715                     ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
  716                         "active" : "passive");
  717 
  718                 /* clear bg scan NOPICK and mark cancel request */
  719                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
  720                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
  721                 /* wake up the scan task */
  722                 scan_signal(ss);
  723         }
  724         IEEE80211_UNLOCK(ic);
  725 }
  726 
  727 /*
  728  * Public access to scan_next for drivers that manage
  729  * scanning themselves (e.g. for firmware-based devices).
  730  */
  731 void
  732 ieee80211_scan_next(struct ieee80211vap *vap)
  733 {
  734         struct ieee80211com *ic = vap->iv_ic;
  735         struct ieee80211_scan_state *ss = ic->ic_scan;
  736 
  737         /* wake up the scan task */
  738         IEEE80211_LOCK(ic);
  739         scan_signal(ss);
  740         IEEE80211_UNLOCK(ic);
  741 }
  742 
  743 /*
  744  * Public access to scan_next for drivers that are not able to scan single
  745  * channels (e.g. for firmware-based devices).
  746  */
  747 void
  748 ieee80211_scan_done(struct ieee80211vap *vap)
  749 {
  750         struct ieee80211com *ic = vap->iv_ic;
  751         struct ieee80211_scan_state *ss;
  752 
  753         IEEE80211_LOCK(ic);
  754         ss = ic->ic_scan;
  755         ss->ss_next = ss->ss_last; /* all channels are complete */
  756         scan_signal(ss);
  757         IEEE80211_UNLOCK(ic);
  758 }
  759 
  760 /*
  761  * Probe the curent channel, if allowed, while scanning.
  762  * If the channel is not marked passive-only then send
  763  * a probe request immediately.  Otherwise mark state and
  764  * listen for beacons on the channel; if we receive something
  765  * then we'll transmit a probe request.
  766  */
  767 void
  768 ieee80211_probe_curchan(struct ieee80211vap *vap, int force)
  769 {
  770         struct ieee80211com *ic = vap->iv_ic;
  771         struct ieee80211_scan_state *ss = ic->ic_scan;
  772         struct ifnet *ifp = vap->iv_ifp;
  773         int i;
  774 
  775         if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
  776                 ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
  777                 return;
  778         }
  779         /*
  780          * Send directed probe requests followed by any
  781          * broadcast probe request.
  782          * XXX remove dependence on ic/vap->iv_bss
  783          */
  784         for (i = 0; i < ss->ss_nssid; i++)
  785                 ieee80211_send_probereq(vap->iv_bss,
  786                         vap->iv_myaddr, ifp->if_broadcastaddr,
  787                         ifp->if_broadcastaddr,
  788                         ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
  789         if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
  790                 ieee80211_send_probereq(vap->iv_bss,
  791                         vap->iv_myaddr, ifp->if_broadcastaddr,
  792                         ifp->if_broadcastaddr,
  793                         "", 0);
  794 }
  795 
  796 /*
  797  * Scan curchan.  If this is an active scan and the channel
  798  * is not marked passive then send probe request frame(s).
  799  * Arrange for the channel change after maxdwell ticks.
  800  */
  801 static void
  802 scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
  803 {
  804         struct ieee80211vap *vap  = ss->ss_vap;
  805 
  806         IEEE80211_LOCK(vap->iv_ic);
  807         if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
  808                 ieee80211_probe_curchan(vap, 0);
  809         callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
  810             maxdwell, scan_signal, ss);
  811         IEEE80211_UNLOCK(vap->iv_ic);
  812 }
  813 
  814 static void
  815 scan_signal(void *arg)
  816 {
  817         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
  818 
  819         IEEE80211_LOCK_ASSERT(ss->ss_ic);
  820 
  821         cv_signal(&SCAN_PRIVATE(ss)->ss_scan_cv);
  822 }
  823 
  824 /*
  825  * Handle mindwell requirements completed; initiate a channel
  826  * change to the next channel asap.
  827  */
  828 static void
  829 scan_mindwell(struct ieee80211_scan_state *ss)
  830 {
  831         struct ieee80211com *ic = ss->ss_ic;
  832 
  833         IEEE80211_LOCK(ic);
  834         scan_signal(ss);
  835         IEEE80211_UNLOCK(ic);
  836 }
  837 
  838 static void
  839 scan_task(void *arg, int pending)
  840 {
  841 #define ISCAN_REP       (ISCAN_MINDWELL | ISCAN_DISCARD)
  842         struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
  843         struct ieee80211vap *vap = ss->ss_vap;
  844         struct ieee80211com *ic = ss->ss_ic;
  845         struct ieee80211_channel *chan;
  846         unsigned long maxdwell, scanend;
  847         int scandone = 0;
  848 
  849         IEEE80211_LOCK(ic);
  850         if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
  851             (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
  852                 /* Cancelled before we started */
  853                 goto done;
  854         }
  855 
  856         if (ss->ss_next == ss->ss_last) {
  857                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  858                         "%s: no channels to scan\n", __func__);
  859                 goto done;
  860         }
  861 
  862         if (vap->iv_opmode == IEEE80211_M_STA &&
  863             vap->iv_state == IEEE80211_S_RUN) {
  864                 if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
  865                         /* Enable station power save mode */
  866                         ieee80211_sta_pwrsave(vap, 1);
  867                         /*
  868                          * Use an 1ms delay so the null data frame has a chance
  869                          * to go out.
  870                          * XXX Should use M_TXCB mechanism to eliminate this.
  871                          */
  872                         cv_timedwait(&SCAN_PRIVATE(ss)->ss_scan_cv,
  873                             IEEE80211_LOCK_OBJ(ic), hz / 1000);
  874                         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
  875                                 goto done;
  876                 }
  877         }
  878 
  879         scanend = ticks + SCAN_PRIVATE(ss)->ss_duration;
  880         IEEE80211_UNLOCK(ic);
  881         ic->ic_scan_start(ic);          /* notify driver */
  882         IEEE80211_LOCK(ic);
  883 
  884         for (;;) {
  885                 scandone = (ss->ss_next >= ss->ss_last) ||
  886                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0;
  887                 if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
  888                     (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT) ||
  889                      time_after(ticks + ss->ss_mindwell, scanend))
  890                         break;
  891 
  892                 chan = ss->ss_chans[ss->ss_next++];
  893 
  894                 /*
  895                  * Watch for truncation due to the scan end time.
  896                  */
  897                 if (time_after(ticks + ss->ss_maxdwell, scanend))
  898                         maxdwell = scanend - ticks;
  899                 else
  900                         maxdwell = ss->ss_maxdwell;
  901 
  902                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  903                     "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
  904                     __func__,
  905                     ieee80211_chan2ieee(ic, ic->ic_curchan),
  906                         channel_type(ic->ic_curchan),
  907                     ieee80211_chan2ieee(ic, chan), channel_type(chan),
  908                     (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
  909                         (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
  910                         "active" : "passive",
  911                     ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
  912 
  913                 /*
  914                  * Potentially change channel and phy mode.
  915                  */
  916                 ic->ic_curchan = chan;
  917                 ic->ic_rt = ieee80211_get_ratetable(chan);
  918                 IEEE80211_UNLOCK(ic);
  919                 /*
  920                  * Perform the channel change and scan unlocked so the driver
  921                  * may sleep. Once set_channel returns the hardware has
  922                  * completed the channel change.
  923                  */
  924                 ic->ic_set_channel(ic);
  925                 ieee80211_radiotap_chan_change(ic);
  926 
  927                 /*
  928                  * Scan curchan.  Drivers for "intelligent hardware"
  929                  * override ic_scan_curchan to tell the device to do
  930                  * the work.  Otherwise we manage the work outselves;
  931                  * sending a probe request (as needed), and arming the
  932                  * timeout to switch channels after maxdwell ticks.
  933                  *
  934                  * scan_curchan should only pause for the time required to
  935                  * prepare/initiate the hardware for the scan (if at all), the
  936                  * below condvar is used to sleep for the channels dwell time
  937                  * and allows it to be signalled for abort.
  938                  */
  939                 ic->ic_scan_curchan(ss, maxdwell);
  940                 IEEE80211_LOCK(ic);
  941 
  942                 SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell;
  943                 /* clear mindwell lock and initial channel change flush */
  944                 SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
  945 
  946                 if ((SCAN_PRIVATE(ss)->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)))
  947                         continue;
  948 
  949                 /* Wait to be signalled to scan the next channel */
  950                 cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv, IEEE80211_LOCK_OBJ(ic));
  951         }
  952         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
  953                 goto done;
  954 
  955         IEEE80211_UNLOCK(ic);
  956         ic->ic_scan_end(ic);            /* notify driver */
  957         IEEE80211_LOCK(ic);
  958 
  959         /*
  960          * Record scan complete time.  Note that we also do
  961          * this when canceled so any background scan will
  962          * not be restarted for a while.
  963          */
  964         if (scandone)
  965                 ic->ic_lastscan = ticks;
  966         /* return to the bss channel */
  967         if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
  968             ic->ic_curchan != ic->ic_bsschan) {
  969                 ieee80211_setupcurchan(ic, ic->ic_bsschan);
  970                 IEEE80211_UNLOCK(ic);
  971                 ic->ic_set_channel(ic);
  972                 ieee80211_radiotap_chan_change(ic);
  973                 IEEE80211_LOCK(ic);
  974         }
  975         /* clear internal flags and any indication of a pick */
  976         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
  977         ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
  978 
  979         /*
  980          * If not canceled and scan completed, do post-processing.
  981          * If the callback function returns 0, then it wants to
  982          * continue/restart scanning.  Unfortunately we needed to
  983          * notify the driver to end the scan above to avoid having
  984          * rx frames alter the scan candidate list.
  985          */
  986         if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 &&
  987             !ss->ss_ops->scan_end(ss, vap) &&
  988             (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
  989             time_before(ticks + ss->ss_mindwell, scanend)) {
  990                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
  991                     "%s: done, restart "
  992                     "[ticks %u, dwell min %lu scanend %lu]\n",
  993                     __func__,
  994                     ticks, ss->ss_mindwell, scanend);
  995                 ss->ss_next = 0;        /* reset to begining */
  996                 if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
  997                         vap->iv_stats.is_scan_active++;
  998                 else
  999                         vap->iv_stats.is_scan_passive++;
 1000 
 1001                 ss->ss_ops->scan_restart(ss, vap);      /* XXX? */
 1002                 ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
 1003                 IEEE80211_UNLOCK(ic);
 1004                 return;
 1005         }
 1006 
 1007         /* past here, scandone is ``true'' if not in bg mode */
 1008         if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
 1009                 scandone = 1;
 1010 
 1011         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 1012             "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
 1013             __func__, scandone ? "done" : "stopped",
 1014             ticks, ss->ss_mindwell, scanend);
 1015 
 1016         /*
 1017          * Clear the SCAN bit first in case frames are
 1018          * pending on the station power save queue.  If
 1019          * we defer this then the dispatch of the frames
 1020          * may generate a request to cancel scanning.
 1021          */
 1022 done:
 1023         ic->ic_flags &= ~IEEE80211_F_SCAN;
 1024         /*
 1025          * Drop out of power save mode when a scan has
 1026          * completed.  If this scan was prematurely terminated
 1027          * because it is a background scan then don't notify
 1028          * the ap; we'll either return to scanning after we
 1029          * receive the beacon frame or we'll drop out of power
 1030          * save mode because the beacon indicates we have frames
 1031          * waiting for us.
 1032          */
 1033         if (scandone) {
 1034                 ieee80211_sta_pwrsave(vap, 0);
 1035                 if (ss->ss_next >= ss->ss_last) {
 1036                         ieee80211_notify_scan_done(vap);
 1037                         ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
 1038                 }
 1039         }
 1040         SCAN_PRIVATE(ss)->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
 1041         ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
 1042         IEEE80211_UNLOCK(ic);
 1043 #undef ISCAN_REP
 1044 }
 1045 
 1046 #ifdef IEEE80211_DEBUG
 1047 static void
 1048 dump_country(const uint8_t *ie)
 1049 {
 1050         const struct ieee80211_country_ie *cie =
 1051            (const struct ieee80211_country_ie *) ie;
 1052         int i, nbands, schan, nchan;
 1053 
 1054         if (cie->len < 3) {
 1055                 printf(" <bogus country ie, len %d>", cie->len);
 1056                 return;
 1057         }
 1058         printf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]);
 1059         nbands = (cie->len - 3) / sizeof(cie->band[0]);
 1060         for (i = 0; i < nbands; i++) {
 1061                 schan = cie->band[i].schan;
 1062                 nchan = cie->band[i].nchan;
 1063                 if (nchan != 1)
 1064                         printf(" %u-%u,%u", schan, schan + nchan-1,
 1065                             cie->band[i].maxtxpwr);
 1066                 else
 1067                         printf(" %u,%u", schan, cie->band[i].maxtxpwr);
 1068         }
 1069         printf("]");
 1070 }
 1071 
 1072 static void
 1073 dump_probe_beacon(uint8_t subtype, int isnew,
 1074         const uint8_t mac[IEEE80211_ADDR_LEN],
 1075         const struct ieee80211_scanparams *sp, int rssi)
 1076 {
 1077 
 1078         printf("[%s] %s%s on chan %u (bss chan %u) ",
 1079             ether_sprintf(mac), isnew ? "new " : "",
 1080             ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT],
 1081             sp->chan, sp->bchan);
 1082         ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
 1083         printf(" rssi %d\n", rssi);
 1084 
 1085         if (isnew) {
 1086                 printf("[%s] caps 0x%x bintval %u erp 0x%x", 
 1087                         ether_sprintf(mac), sp->capinfo, sp->bintval, sp->erp);
 1088                 if (sp->country != NULL)
 1089                         dump_country(sp->country);
 1090                 printf("\n");
 1091         }
 1092 }
 1093 #endif /* IEEE80211_DEBUG */
 1094 
 1095 /*
 1096  * Process a beacon or probe response frame.
 1097  */
 1098 void
 1099 ieee80211_add_scan(struct ieee80211vap *vap,
 1100         const struct ieee80211_scanparams *sp,
 1101         const struct ieee80211_frame *wh,
 1102         int subtype, int rssi, int noise)
 1103 {
 1104         struct ieee80211com *ic = vap->iv_ic;
 1105         struct ieee80211_scan_state *ss = ic->ic_scan;
 1106 
 1107         /* XXX locking */
 1108         /*
 1109          * Frames received during startup are discarded to avoid
 1110          * using scan state setup on the initial entry to the timer
 1111          * callback.  This can occur because the device may enable
 1112          * rx prior to our doing the initial channel change in the
 1113          * timer routine.
 1114          */
 1115         if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
 1116                 return;
 1117 #ifdef IEEE80211_DEBUG
 1118         if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
 1119                 dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
 1120 #endif
 1121         if (ss->ss_ops != NULL &&
 1122             ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise)) {
 1123                 /*
 1124                  * If we've reached the min dwell time terminate
 1125                  * the timer so we'll switch to the next channel.
 1126                  */
 1127                 if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
 1128                     time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
 1129                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
 1130                             "%s: chan %3d%c min dwell met (%u > %lu)\n",
 1131                             __func__,
 1132                             ieee80211_chan2ieee(ic, ic->ic_curchan),
 1133                                 channel_type(ic->ic_curchan),
 1134                             ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
 1135                         SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
 1136                         /*
 1137                          * NB: trigger at next clock tick or wait for the
 1138                          * hardware.
 1139                          */
 1140                         ic->ic_scan_mindwell(ss);
 1141                 }
 1142         }
 1143 }
 1144 
 1145 /*
 1146  * Timeout/age scan cache entries; called from sta timeout
 1147  * timer (XXX should be self-contained).
 1148  */
 1149 void
 1150 ieee80211_scan_timeout(struct ieee80211com *ic)
 1151 {
 1152         struct ieee80211_scan_state *ss = ic->ic_scan;
 1153 
 1154         if (ss->ss_ops != NULL)
 1155                 ss->ss_ops->scan_age(ss);
 1156 }
 1157 
 1158 /*
 1159  * Mark a scan cache entry after a successful associate.
 1160  */
 1161 void
 1162 ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
 1163 {
 1164         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
 1165 
 1166         if (ss->ss_ops != NULL) {
 1167                 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN,
 1168                         mac, "%s",  __func__);
 1169                 ss->ss_ops->scan_assoc_success(ss, mac);
 1170         }
 1171 }
 1172 
 1173 /*
 1174  * Demerit a scan cache entry after failing to associate.
 1175  */
 1176 void
 1177 ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
 1178         const uint8_t mac[], int reason)
 1179 {
 1180         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
 1181 
 1182         if (ss->ss_ops != NULL) {
 1183                 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac,
 1184                         "%s: reason %u", __func__, reason);
 1185                 ss->ss_ops->scan_assoc_fail(ss, mac, reason);
 1186         }
 1187 }
 1188 
 1189 /*
 1190  * Iterate over the contents of the scan cache.
 1191  */
 1192 void
 1193 ieee80211_scan_iterate(struct ieee80211vap *vap,
 1194         ieee80211_scan_iter_func *f, void *arg)
 1195 {
 1196         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
 1197 
 1198         if (ss->ss_ops != NULL)
 1199                 ss->ss_ops->scan_iterate(ss, f, arg);
 1200 }
 1201 
 1202 /*
 1203  * Flush the contents of the scan cache.
 1204  */
 1205 void
 1206 ieee80211_scan_flush(struct ieee80211vap *vap)
 1207 {
 1208         struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
 1209 
 1210         if (ss->ss_ops != NULL && ss->ss_vap == vap) {
 1211                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n",  __func__);
 1212                 ss->ss_ops->scan_flush(ss);
 1213         }
 1214 }
 1215 
 1216 /*
 1217  * Check the scan cache for an ap/channel to use; if that
 1218  * fails then kick off a new scan.
 1219  */
 1220 struct ieee80211_channel *
 1221 ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
 1222 {
 1223         struct ieee80211_scan_state *ss = ic->ic_scan;
 1224 
 1225         IEEE80211_LOCK_ASSERT(ic);
 1226 
 1227         if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
 1228                 /* XXX printf? */
 1229                 return NULL;
 1230         }
 1231         if (ss->ss_ops->scan_pickchan == NULL) {
 1232                 IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
 1233                     "%s: scan module does not support picking a channel, "
 1234                     "opmode %s\n", __func__, ss->ss_vap->iv_opmode);
 1235                 return NULL;
 1236         }
 1237         return ss->ss_ops->scan_pickchan(ss, flags);
 1238 }

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