[dragonfly.git] / sys / netproto / 802_11 / wlan / ieee80211_node.c

/*
 * Copyright (c) 2001 Atsushi Onoe
 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/net80211/ieee80211_node.c,v 1.48.2.10 2006/03/13 03:05:47 sam Exp $
 * $DragonFly: src/sys/netproto/802_11/wlan/ieee80211_node.c,v 1.2 2006/05/18 13:51:46 sephe Exp $
 */

#include <sys/param.h>
#include <sys/systm.h> 
#include <sys/mbuf.h>   
#include <sys/malloc.h>
#include <sys/kernel.h>

#include <sys/socket.h>
 
#include <net/if.h>
#include <net/if_arp.h>
#include <net/if_media.h>
#include <net/ethernet.h>

#include <netproto/802_11/ieee80211_var.h>

#include <net/bpf.h>

/*
 * Association id's are managed with a bit vector.
 */
#define IEEE80211_AID_SET(b, w) \
        ((w)[IEEE80211_AID(b) / 32] |= (1 << (IEEE80211_AID(b) % 32)))
#define IEEE80211_AID_CLR(b, w) \
        ((w)[IEEE80211_AID(b) / 32] &= ~(1 << (IEEE80211_AID(b) % 32)))
#define IEEE80211_AID_ISSET(b, w) \
        ((w)[IEEE80211_AID(b) / 32] & (1 << (IEEE80211_AID(b) % 32)))

static struct ieee80211_node *node_alloc(struct ieee80211_node_table *);
static void node_cleanup(struct ieee80211_node *);
static void node_free(struct ieee80211_node *);
static uint8_t node_getrssi(const struct ieee80211_node *);

static void ieee80211_setup_node(struct ieee80211_node_table *,
                struct ieee80211_node *, const uint8_t *);
static void _ieee80211_free_node(struct ieee80211_node *);
static void ieee80211_free_allnodes(struct ieee80211_node_table *);

static void ieee80211_timeout_scan_candidates(struct ieee80211_node_table *);
static void ieee80211_timeout_stations(struct ieee80211_node_table *);

static void ieee80211_set_tim(struct ieee80211_node *, int set);

static void ieee80211_node_table_init(struct ieee80211com *ic,
        struct ieee80211_node_table *nt, const char *name,
        int inact, int keyixmax,
        void (*timeout)(struct ieee80211_node_table *));
static void ieee80211_node_table_cleanup(struct ieee80211_node_table *nt);

MALLOC_DEFINE(M_80211_NODE, "80211node", "802.11 node state");

void
ieee80211_node_attach(struct ieee80211com *ic)
{
        ic->ic_node_alloc = node_alloc;
        ic->ic_node_free = node_free;
        ic->ic_node_cleanup = node_cleanup;
        ic->ic_node_getrssi = node_getrssi;

        /* default station inactivity timer setings */
        ic->ic_inact_init = IEEE80211_INACT_INIT;
        ic->ic_inact_auth = IEEE80211_INACT_AUTH;
        ic->ic_inact_run = IEEE80211_INACT_RUN;
        ic->ic_inact_probe = IEEE80211_INACT_PROBE;

        /* NB: driver should override */
        ic->ic_max_aid = IEEE80211_AID_DEF;
        ic->ic_set_tim = ieee80211_set_tim;
}

void
ieee80211_node_lateattach(struct ieee80211com *ic)
{
        struct ieee80211_rsnparms *rsn;

        if (ic->ic_max_aid > IEEE80211_AID_MAX)
                ic->ic_max_aid = IEEE80211_AID_MAX;

        ic->ic_aid_bitmap =
                malloc(howmany(ic->ic_max_aid, 32) * sizeof(uint32_t),
                       M_DEVBUF, M_WAITOK | M_ZERO);

        /* XXX defer until using hostap/ibss mode */
        ic->ic_tim_len = howmany(ic->ic_max_aid, 8) * sizeof(uint8_t);
        ic->ic_tim_bitmap = malloc(ic->ic_tim_len, M_DEVBUF,
                                   M_WAITOK | M_ZERO);

        ieee80211_node_table_init(ic, &ic->ic_sta, "station",
                IEEE80211_INACT_INIT, ic->ic_crypto.cs_max_keyix,
                ieee80211_timeout_stations);
        ieee80211_node_table_init(ic, &ic->ic_scan, "scan",
                IEEE80211_INACT_SCAN, 0,
                ieee80211_timeout_scan_candidates);

        ieee80211_reset_bss(ic);
        /*
         * Setup "global settings" in the bss node so that
         * each new station automatically inherits them.
         */
        rsn = &ic->ic_bss->ni_rsn;
        /* WEP, TKIP, and AES-CCM are always supported */
        rsn->rsn_ucastcipherset |= 1<<IEEE80211_CIPHER_WEP;
        rsn->rsn_ucastcipherset |= 1<<IEEE80211_CIPHER_TKIP;
        rsn->rsn_ucastcipherset |= 1<<IEEE80211_CIPHER_AES_CCM;
        if (ic->ic_caps & IEEE80211_C_AES)
                rsn->rsn_ucastcipherset |= 1<<IEEE80211_CIPHER_AES_OCB;
        if (ic->ic_caps & IEEE80211_C_CKIP)
                rsn->rsn_ucastcipherset |= 1<<IEEE80211_CIPHER_CKIP;
        /*
         * Default unicast cipher to WEP for 802.1x use.  If
         * WPA is enabled the management code will set these
         * values to reflect.
         */
        rsn->rsn_ucastcipher = IEEE80211_CIPHER_WEP;
        rsn->rsn_ucastkeylen = 104 / NBBY;
        /*
         * WPA says the multicast cipher is the lowest unicast
         * cipher supported.  But we skip WEP which would
         * otherwise be used based on this criteria.
         */
        rsn->rsn_mcastcipher = IEEE80211_CIPHER_TKIP;
        rsn->rsn_mcastkeylen = 128 / NBBY;

        /*
         * We support both WPA-PSK and 802.1x; the one used
         * is determined by the authentication mode and the
         * setting of the PSK state.
         */
        rsn->rsn_keymgmtset = WPA_ASE_8021X_UNSPEC | WPA_ASE_8021X_PSK;
        rsn->rsn_keymgmt = WPA_ASE_8021X_PSK;

        ic->ic_auth = ieee80211_authenticator_get(ic->ic_bss->ni_authmode);
}

void
ieee80211_node_detach(struct ieee80211com *ic)
{
        if (ic->ic_bss != NULL) {
                ieee80211_free_node(ic->ic_bss);
                ic->ic_bss = NULL;
        }
        ieee80211_node_table_cleanup(&ic->ic_scan);
        ieee80211_node_table_cleanup(&ic->ic_sta);
        if (ic->ic_aid_bitmap != NULL) {
                free(ic->ic_aid_bitmap, M_DEVBUF);
                ic->ic_aid_bitmap = NULL;
        }
        if (ic->ic_tim_bitmap != NULL) {
                free(ic->ic_tim_bitmap, M_DEVBUF);
                ic->ic_tim_bitmap = NULL;
        }
}

/* 
 * Port authorize/unauthorize interfaces for use by an authenticator.
 */

void
ieee80211_node_authorize(struct ieee80211_node *ni)
{
        struct ieee80211com *ic = ni->ni_ic;

        ni->ni_flags |= IEEE80211_NODE_AUTH;
        ni->ni_inact_reload = ic->ic_inact_run;
}

void
ieee80211_node_unauthorize(struct ieee80211_node *ni)
{
        ni->ni_flags &= ~IEEE80211_NODE_AUTH;
}

/*
 * Set/change the channel.  The rate set is also updated as
 * to insure a consistent view by drivers.
 */
static void
ieee80211_set_chan(struct ieee80211com *ic,
        struct ieee80211_node *ni, struct ieee80211_channel *chan)
{
        if (chan == IEEE80211_CHAN_ANYC)        /* XXX while scanning */
                chan = ic->ic_curchan;
        ni->ni_chan = chan;
        ni->ni_rates = ic->ic_sup_rates[ieee80211_chan2mode(ic, chan)];
}

/*
 * AP scanning support.
 */

#ifdef IEEE80211_DEBUG
static void
dump_chanlist(const u_char chans[])
{
        const char *sep;
        int i;

        sep = " ";
        for (i = 0; i < IEEE80211_CHAN_MAX; i++)
                if (isset(chans, i)) {
                        printf("%s%u", sep, i);
                        sep = ", ";
                }
}
#endif /* IEEE80211_DEBUG */

/*
 * Initialize the channel set to scan based on the
 * of available channels and the current PHY mode.
 */
static void
ieee80211_reset_scan(struct ieee80211com *ic)
{

        /* XXX ic_des_chan should be handled with ic_chan_active */
        if (ic->ic_des_chan != IEEE80211_CHAN_ANYC) {
                memset(ic->ic_chan_scan, 0, sizeof(ic->ic_chan_scan));
                setbit(ic->ic_chan_scan,
                        ieee80211_chan2ieee(ic, ic->ic_des_chan));
        } else
                memcpy(ic->ic_chan_scan, ic->ic_chan_active,
                        sizeof(ic->ic_chan_active));
#ifdef IEEE80211_DEBUG
        if (ieee80211_msg_scan(ic)) {
                printf("%s: scan set:", __func__);
                dump_chanlist(ic->ic_chan_scan);
                printf(" start chan %u\n",
                        ieee80211_chan2ieee(ic, ic->ic_curchan));
        }
#endif /* IEEE80211_DEBUG */
}

/*
 * Begin an active scan.
 */
void
ieee80211_begin_scan(struct ieee80211com *ic, int reset)
{
        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        /*
         * In all but hostap mode scanning starts off in
         * an active mode before switching to passive.
         */
        if (ic->ic_opmode != IEEE80211_M_HOSTAP) {
                ic->ic_flags |= IEEE80211_F_ASCAN;
                ic->ic_stats.is_scan_active++;
        } else
                ic->ic_stats.is_scan_passive++;
        IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
                "begin %s scan in %s mode\n",
                (ic->ic_flags & IEEE80211_F_ASCAN) ?  "active" : "passive",
                ieee80211_phymode_name[ic->ic_curmode]);
        /*
         * Clear scan state and flush any previously seen AP's.
         */
        ieee80211_reset_scan(ic);
        if (reset)
                ieee80211_free_allnodes(&ic->ic_scan);

        ic->ic_flags |= IEEE80211_F_SCAN;

        /* Scan the next channel. */
        ieee80211_next_scan(ic);
}

/*
 * Switch to the next channel marked for scanning.
 */
int
ieee80211_next_scan(struct ieee80211com *ic)
{
        struct ieee80211_channel *chan;

        /*
         * Insure any previous mgt frame timeouts don't fire.
         * This assumes the driver does the right thing in
         * flushing anything queued in the driver and below.
         */
        ic->ic_mgt_timer = 0;
        ic->ic_flags_ext &= ~IEEE80211_FEXT_PROBECHAN;

        chan = ic->ic_curchan;
        do {
                if (++chan > &ic->ic_channels[IEEE80211_CHAN_MAX])
                        chan = &ic->ic_channels[0];
                if (isset(ic->ic_chan_scan, ieee80211_chan2ieee(ic, chan))) {
                        clrbit(ic->ic_chan_scan, ieee80211_chan2ieee(ic, chan));
                        IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
                            "%s: chan %d->%d\n", __func__,
                            ieee80211_chan2ieee(ic, ic->ic_curchan),
                            ieee80211_chan2ieee(ic, chan));
                        ic->ic_curchan = chan;
                        /*
                         * XXX drivers should do this as needed,
                         * XXX for now maintain compatibility
                         */
                        ic->ic_bss->ni_rates =
                                ic->ic_sup_rates[ieee80211_chan2mode(ic, chan)];
                        ieee80211_new_state(ic, IEEE80211_S_SCAN, -1);
                        return 1;
                }
        } while (chan != ic->ic_curchan);
        ieee80211_end_scan(ic);
        return 0;
}

/*
 * Probe the curent channel, if allowed, while scanning.
 * If the channel is not marked passive-only then send
 * a probe request immediately.  Otherwise mark state and
 * listen for beacons on the channel; if we receive something
 * then we'll transmit a probe request.
 */
void
ieee80211_probe_curchan(struct ieee80211com *ic, int force)
{
        struct ifnet *ifp = ic->ic_ifp;

        if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 || force) {
                /*
                 * XXX send both broadcast+directed probe request
                 */
                ieee80211_send_probereq(ic->ic_bss,
                        ic->ic_myaddr, ifp->if_broadcastaddr,
                        ifp->if_broadcastaddr,
                        ic->ic_des_essid, ic->ic_des_esslen,
                        ic->ic_opt_ie, ic->ic_opt_ie_len);
        } else
                ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
}

static __inline void
copy_bss(struct ieee80211_node *nbss, const struct ieee80211_node *obss)
{
        /* propagate useful state */
        nbss->ni_authmode = obss->ni_authmode;
        nbss->ni_txpower = obss->ni_txpower;
        nbss->ni_vlan = obss->ni_vlan;
        nbss->ni_rsn = obss->ni_rsn;
        /* XXX statistics? */
}

void
ieee80211_create_ibss(struct ieee80211com* ic, struct ieee80211_channel *chan)
{
        struct ieee80211_node_table *nt;
        struct ieee80211_node *ni;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
                "%s: creating ibss\n", __func__);

        /*
         * Create the station/neighbor table.  Note that for adhoc
         * mode we make the initial inactivity timer longer since
         * we create nodes only through discovery and they typically
         * are long-lived associations.
         */
        nt = &ic->ic_sta;
        if (ic->ic_opmode == IEEE80211_M_HOSTAP) {
                nt->nt_name = "station";
                nt->nt_inact_init = ic->ic_inact_init;
        } else {
                nt->nt_name = "neighbor";
                nt->nt_inact_init = ic->ic_inact_run;
        }

        ni = ieee80211_alloc_node(&ic->ic_sta, ic->ic_myaddr);
        if (ni == NULL) {
                /* XXX recovery? */
                return;
        }
        IEEE80211_ADDR_COPY(ni->ni_bssid, ic->ic_myaddr);
        ni->ni_esslen = ic->ic_des_esslen;
        memcpy(ni->ni_essid, ic->ic_des_essid, ni->ni_esslen);
        copy_bss(ni, ic->ic_bss);
        ni->ni_intval = ic->ic_bintval;
        if (ic->ic_flags & IEEE80211_F_PRIVACY)
                ni->ni_capinfo |= IEEE80211_CAPINFO_PRIVACY;
        if (ic->ic_phytype == IEEE80211_T_FH) {
                ni->ni_fhdwell = 200;   /* XXX */
                ni->ni_fhindex = 1;
        }
        if (ic->ic_opmode == IEEE80211_M_IBSS) {
                ic->ic_flags |= IEEE80211_F_SIBSS;
                ni->ni_capinfo |= IEEE80211_CAPINFO_IBSS;       /* XXX */
                if (ic->ic_flags & IEEE80211_F_DESBSSID)
                        IEEE80211_ADDR_COPY(ni->ni_bssid, ic->ic_des_bssid);
                else
                        ni->ni_bssid[0] |= 0x02;        /* local bit for IBSS */
        } else if (ic->ic_opmode == IEEE80211_M_AHDEMO) {
                if (ic->ic_flags & IEEE80211_F_DESBSSID)
                        IEEE80211_ADDR_COPY(ni->ni_bssid, ic->ic_des_bssid);
                else
                        memset(ni->ni_bssid, 0, IEEE80211_ADDR_LEN);
        }
        /* 
         * Fix the channel and related attributes.
         */
        ieee80211_set_chan(ic, ni, chan);
        ic->ic_curchan = chan;
        ic->ic_curmode = ieee80211_chan2mode(ic, chan);
        /*
         * Do mode-specific rate setup.
         */
        if (ic->ic_curmode == IEEE80211_MODE_11G) {
                /*
                 * Use a mixed 11b/11g rate set.
                 */
                ieee80211_set11gbasicrates(&ni->ni_rates, IEEE80211_MODE_11G);
        } else if (ic->ic_curmode == IEEE80211_MODE_11B) {
                /*
                 * Force pure 11b rate set.
                 */
                ieee80211_set11gbasicrates(&ni->ni_rates, IEEE80211_MODE_11B);
        }

        ieee80211_sta_join(ic, ieee80211_ref_node(ni));
}

void
ieee80211_reset_bss(struct ieee80211com *ic)
{
        struct ieee80211_node *ni, *obss;

        ieee80211_node_table_reset(&ic->ic_scan);
        ieee80211_node_table_reset(&ic->ic_sta);

        ni = ieee80211_alloc_node(&ic->ic_scan, ic->ic_myaddr);
        KASSERT(ni != NULL, ("unable to setup inital BSS node"));
        obss = ic->ic_bss;
        ic->ic_bss = ieee80211_ref_node(ni);
        if (obss != NULL) {
                copy_bss(ni, obss);
                ni->ni_intval = ic->ic_bintval;
                ieee80211_free_node(obss);
        }
}

/* XXX tunable */
#define STA_FAILS_MAX   2               /* assoc failures before ignored */

static int
ieee80211_match_bss(struct ieee80211com *ic, struct ieee80211_node *ni)
{
        uint8_t rate;
        int fail;

        fail = 0;
        if (isclr(ic->ic_chan_active, ieee80211_chan2ieee(ic, ni->ni_chan)))
                fail |= 0x01;
        if (ic->ic_des_chan != IEEE80211_CHAN_ANYC &&
            ni->ni_chan != ic->ic_des_chan)
                fail |= 0x01;
        if (ic->ic_opmode == IEEE80211_M_IBSS) {
                if ((ni->ni_capinfo & IEEE80211_CAPINFO_IBSS) == 0)
                        fail |= 0x02;
        } else {
                if ((ni->ni_capinfo & IEEE80211_CAPINFO_ESS) == 0)
                        fail |= 0x02;
        }
        if (ic->ic_flags & IEEE80211_F_PRIVACY) {
                if ((ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0)
                        fail |= 0x04;
        } else {
                /* XXX does this mean privacy is supported or required? */
                if (ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY)
                        fail |= 0x04;
        }
        rate = ieee80211_fix_rate(ni, IEEE80211_F_DONEGO | IEEE80211_F_DOFRATE);
        if (rate & IEEE80211_RATE_BASIC)
                fail |= 0x08;
        if (ic->ic_des_esslen != 0 &&
            (ni->ni_esslen != ic->ic_des_esslen ||
             memcmp(ni->ni_essid, ic->ic_des_essid, ic->ic_des_esslen) != 0))
                fail |= 0x10;
        if ((ic->ic_flags & IEEE80211_F_DESBSSID) &&
            !IEEE80211_ADDR_EQ(ic->ic_des_bssid, ni->ni_bssid))
                fail |= 0x20;
        if (ni->ni_fails >= STA_FAILS_MAX)
                fail |= 0x40;
#ifdef IEEE80211_DEBUG
        if (ieee80211_msg_scan(ic)) {
                printf(" %c %6D",
                    fail & 0x40 ? '=' : fail & 0x80 ? '^' : fail ? '-' : '+',
                    ni->ni_macaddr, ":");
                printf(" %6D%c", ni->ni_bssid, ":",
                    fail & 0x20 ? '!' : ' ');
                printf(" %3d%c", ieee80211_chan2ieee(ic, ni->ni_chan),
                        fail & 0x01 ? '!' : ' ');
                printf(" %+4d", ni->ni_rssi);
                printf(" %2dM%c", (rate & IEEE80211_RATE_VAL) / 2,
                    fail & 0x08 ? '!' : ' ');
                printf(" %4s%c",
                    (ni->ni_capinfo & IEEE80211_CAPINFO_ESS) ? "ess" :
                    (ni->ni_capinfo & IEEE80211_CAPINFO_IBSS) ? "ibss" :
                    "????",
                    fail & 0x02 ? '!' : ' ');
                printf(" %3s%c ",
                    (ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) ?
                    "wep" : "no",
                    fail & 0x04 ? '!' : ' ');
                ieee80211_print_essid(ni->ni_essid, ni->ni_esslen);
                printf("%s\n", fail & 0x10 ? "!" : "");
        }
#endif
        return fail;
}

static __inline uint8_t
maxrate(const struct ieee80211_node *ni)
{
        const struct ieee80211_rateset *rs = &ni->ni_rates;
        /* NB: assumes rate set is sorted (happens on frame receive) */
        return rs->rs_rates[rs->rs_nrates-1] & IEEE80211_RATE_VAL;
}

/*
 * Compare the capabilities of two nodes and decide which is
 * more desirable (return >0 if a is considered better).  Note
 * that we assume compatibility/usability has already been checked
 * so we don't need to (e.g. validate whether privacy is supported).
 * Used to select the best scan candidate for association in a BSS.
 */
static int
ieee80211_node_compare(struct ieee80211com *ic,
                       const struct ieee80211_node *a,
                       const struct ieee80211_node *b)
{
#define ABS(a)  ((a) < 0 ? -(a) : (a))
        uint8_t maxa, maxb;
        uint8_t rssia, rssib;
        int weight;

        /* privacy support preferred */
        if ((a->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) &&
            (b->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0)
                return 1;
        if ((a->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0 &&
            (b->ni_capinfo & IEEE80211_CAPINFO_PRIVACY))
                return -1;

        /* compare count of previous failures */
        weight = b->ni_fails - a->ni_fails;
        if (ABS(weight) > 1)
                return weight;

        rssia = ic->ic_node_getrssi(a);
        rssib = ic->ic_node_getrssi(b);
        if (ABS(rssib - rssia) < 5) {
                /* best/max rate preferred if signal level close enough XXX */
                maxa = maxrate(a);
                maxb = maxrate(b);
                if (maxa != maxb)
                        return maxa - maxb;
                /* XXX use freq for channel preference */
                /* for now just prefer 5Ghz band to all other bands */
                if (IEEE80211_IS_CHAN_5GHZ(a->ni_chan) &&
                   !IEEE80211_IS_CHAN_5GHZ(b->ni_chan))
                        return 1;
                if (!IEEE80211_IS_CHAN_5GHZ(a->ni_chan) &&
                     IEEE80211_IS_CHAN_5GHZ(b->ni_chan))
                        return -1;
        }
        /* all things being equal, use signal level */
        return rssia - rssib;
#undef ABS
}

/*
 * Mark an ongoing scan stopped.
 */
void
ieee80211_cancel_scan(struct ieee80211com *ic)
{

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, "%s: end %s scan\n",
                __func__,
                (ic->ic_flags & IEEE80211_F_ASCAN) ?  "active" : "passive");

        ic->ic_flags &= ~(IEEE80211_F_SCAN | IEEE80211_F_ASCAN);
        ic->ic_flags_ext &= ~IEEE80211_FEXT_PROBECHAN;
}

/*
 * Complete a scan of potential channels.
 */
void
ieee80211_end_scan(struct ieee80211com *ic)
{
        struct ieee80211_node_table *nt = &ic->ic_scan;
        struct ieee80211_node *ni, *selbs;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        ieee80211_cancel_scan(ic);
        ieee80211_notify_scan_done(ic);

        if (ic->ic_opmode == IEEE80211_M_HOSTAP) {
                uint8_t maxrssi[IEEE80211_CHAN_MAX];    /* XXX off stack? */
                int i, bestchan;
                uint8_t rssi;

                /*
                 * The passive scan to look for existing AP's completed,
                 * select a channel to camp on.  Identify the channels
                 * that already have one or more AP's and try to locate
                 * an unoccupied one.  If that fails, pick a channel that
                 * looks to be quietest.
                 */
                memset(maxrssi, 0, sizeof(maxrssi));
                TAILQ_FOREACH(ni, &nt->nt_node, ni_list) {
                        rssi = ic->ic_node_getrssi(ni);
                        i = ieee80211_chan2ieee(ic, ni->ni_chan);
                        if (rssi > maxrssi[i])
                                maxrssi[i] = rssi;
                }
                /* XXX select channel more intelligently */
                bestchan = -1;
                for (i = 0; i < IEEE80211_CHAN_MAX; i++)
                        if (isset(ic->ic_chan_active, i)) {
                                /*
                                 * If the channel is unoccupied the max rssi
                                 * should be zero; just take it.  Otherwise
                                 * track the channel with the lowest rssi and
                                 * use that when all channels appear occupied.
                                 */
                                if (maxrssi[i] == 0) {
                                        bestchan = i;
                                        break;
                                }
                                if (bestchan == -1 ||
                                    maxrssi[i] < maxrssi[bestchan])
                                        bestchan = i;
                        }
                if (bestchan != -1) {
                        ieee80211_create_ibss(ic, &ic->ic_channels[bestchan]);
                        return;
                }
                /* no suitable channel, should not happen */
        }

        /*
         * When manually sequencing the state machine; scan just once
         * regardless of whether we have a candidate or not.  The
         * controlling application is expected to setup state and
         * initiate an association.
         */
        if (ic->ic_roaming == IEEE80211_ROAMING_MANUAL)
                return;
        /*
         * Automatic sequencing; look for a candidate and
         * if found join the network.
         */
        /* NB: unlocked read should be ok */
        if (TAILQ_FIRST(&nt->nt_node) == NULL) {
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
                        "%s: no scan candidate\n", __func__);
  notfound:
                if (ic->ic_opmode == IEEE80211_M_IBSS &&
                    (ic->ic_flags & IEEE80211_F_IBSSON) &&
                    ic->ic_des_esslen != 0) {
                        ieee80211_create_ibss(ic, ic->ic_ibss_chan);
                        return;
                }
                /*
                 * Decrement the failure counts so entries will be
                 * reconsidered the next time around.  We really want
                 * to do this only for sta's where we've previously
                 * had some success.
                 */
                TAILQ_FOREACH(ni, &nt->nt_node, ni_list)
                        if (ni->ni_fails)
                                ni->ni_fails--;
                /*
                 * Reset the list of channels to scan and start again.
                 */
                ieee80211_reset_scan(ic);
                ic->ic_flags |= IEEE80211_F_SCAN;
                ieee80211_next_scan(ic);
                return;
        }
        selbs = NULL;
        IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, "\t%s\n",
            "macaddr          bssid         chan  rssi rate flag  wep  essid");
        TAILQ_FOREACH(ni, &nt->nt_node, ni_list) {
                if (ieee80211_match_bss(ic, ni) == 0) {
                        if (selbs == NULL)
                                selbs = ni;
                        else if (ieee80211_node_compare(ic, ni, selbs) > 0)
                                selbs = ni;
                }
        }
        if (selbs != NULL)              /* NB: grab ref while dropping lock */
                ieee80211_ref_node(selbs);
        if (selbs == NULL)
                goto notfound;
        if (!ieee80211_sta_join(ic, selbs)) {
                ieee80211_free_node(selbs);
                goto notfound;
        }
}
 
/*
 * Handle 802.11 ad hoc network merge.  The
 * convention, set by the Wireless Ethernet Compatibility Alliance
 * (WECA), is that an 802.11 station will change its BSSID to match
 * the "oldest" 802.11 ad hoc network, on the same channel, that
 * has the station's desired SSID.  The "oldest" 802.11 network
 * sends beacons with the greatest TSF timestamp.
 *
 * The caller is assumed to validate TSF's before attempting a merge.
 *
 * Return !0 if the BSSID changed, 0 otherwise.
 */
int
ieee80211_ibss_merge(struct ieee80211_node *ni)
{
        struct ieee80211com *ic = ni->ni_ic;

        if (ni == ic->ic_bss ||
            IEEE80211_ADDR_EQ(ni->ni_bssid, ic->ic_bss->ni_bssid)) {
                /* unchanged, nothing to do */
                return 0;
        }
        if (ieee80211_match_bss(ic, ni) != 0) { /* capabilities mismatch */
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                    "%s: merge failed, capabilities mismatch\n", __func__);
                ic->ic_stats.is_ibss_capmismatch++;
                return 0;
        }
        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                "%6D: new bssid %s: %s preamble, %s slot time%s\n", __func__,
                ni->ni_bssid, ":",
                ic->ic_flags&IEEE80211_F_SHPREAMBLE ? "short" : "long",
                ic->ic_flags&IEEE80211_F_SHSLOT ? "short" : "long",
                ic->ic_flags&IEEE80211_F_USEPROT ? ", protection" : ""
        );
        return ieee80211_sta_join(ic, ieee80211_ref_node(ni));
}

/*
 * Join the specified IBSS/BSS network.  The node is assumed to
 * be passed in with a held reference.
 */
int
ieee80211_sta_join(struct ieee80211com *ic, struct ieee80211_node *selbs)
{
        struct ieee80211_node *obss;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        if (ic->ic_opmode == IEEE80211_M_IBSS) {
                struct ieee80211_node_table *nt;
                /*
                 * Delete unusable rates; we've already checked
                 * that the negotiated rate set is acceptable.
                 */
                ieee80211_fix_rate(selbs, IEEE80211_F_DODEL);
                /*
                 * Fillin the neighbor table; it will already
                 * exist if we are simply switching mastership.
                 * XXX ic_sta always setup so this is unnecessary?
                 */
                nt = &ic->ic_sta;
                nt->nt_name = "neighbor";
                nt->nt_inact_init = ic->ic_inact_run;
        }

        /*
         * Committed to selbs, setup state.
         */
        obss = ic->ic_bss;
        ic->ic_bss = selbs;             /* NB: caller assumed to bump refcnt */
        if (obss != NULL) {
                copy_bss(selbs, obss);
                ieee80211_free_node(obss);
        }
        /*
         * Set the erp state (mostly the slot time) to deal with
         * the auto-select case; this should be redundant if the
         * mode is locked.
         */ 
        ic->ic_curmode = ieee80211_chan2mode(ic, selbs->ni_chan);
        ic->ic_curchan = selbs->ni_chan;
        ieee80211_reset_erp(ic);
        ieee80211_wme_initparams(ic);

        if (ic->ic_opmode == IEEE80211_M_STA)
                ieee80211_new_state(ic, IEEE80211_S_AUTH, -1);
        else
                ieee80211_new_state(ic, IEEE80211_S_RUN, -1);
        return 1;
}

/*
 * Leave the specified IBSS/BSS network.  The node is assumed to
 * be passed in with a held reference.
 */
void
ieee80211_sta_leave(struct ieee80211com *ic, struct ieee80211_node *ni)
{
        ic->ic_node_cleanup(ni);
        ieee80211_notify_node_leave(ic, ni);
}

static struct ieee80211_node *
node_alloc(struct ieee80211_node_table *nt)
{
        struct ieee80211_node *ni;

        ni = malloc(sizeof(struct ieee80211_node), M_80211_NODE,
                    M_NOWAIT | M_ZERO);
        return ni;
}

/*
 * Reclaim any resources in a node and reset any critical
 * state.  Typically nodes are free'd immediately after,
 * but in some cases the storage may be reused so we need
 * to insure consistent state (should probably fix that).
 */
static void
node_cleanup(struct ieee80211_node *ni)
{
#define N(a)    (sizeof(a)/sizeof(a[0]))
        struct ieee80211com *ic = ni->ni_ic;
        int i, qlen;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        /* NB: preserve ni_table */
        if (ni->ni_flags & IEEE80211_NODE_PWR_MGT) {
                ic->ic_ps_sta--;
                ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_POWER,
                    "[%6D] power save mode off, %u sta's in ps mode\n",
                    ni->ni_macaddr, ":", ic->ic_ps_sta);
        }
        /*
         * Clear AREF flag that marks the authorization refcnt bump
         * has happened.  This is probably not needed as the node
         * should always be removed from the table so not found but
         * do it just in case.
         */
        ni->ni_flags &= ~IEEE80211_NODE_AREF;

        /*
         * Drain power save queue and, if needed, clear TIM.
         */
        IEEE80211_NODE_SAVEQ_DRAIN(ni, qlen);
        if (qlen != 0 && ic->ic_set_tim != NULL)
                ic->ic_set_tim(ni, 0);

        ni->ni_associd = 0;
        if (ni->ni_challenge != NULL) {
                free(ni->ni_challenge, M_DEVBUF);
                ni->ni_challenge = NULL;
        }
        /*
         * Preserve SSID, WPA, and WME ie's so the bss node is
         * reusable during a re-auth/re-assoc state transition.
         * If we remove these data they will not be recreated
         * because they come from a probe-response or beacon frame
         * which cannot be expected prior to the association-response.
         * This should not be an issue when operating in other modes
         * as stations leaving always go through a full state transition
         * which will rebuild this state.
         *
         * XXX does this leave us open to inheriting old state?
         */
        for (i = 0; i < N(ni->ni_rxfrag); i++)
                if (ni->ni_rxfrag[i] != NULL) {
                        m_freem(ni->ni_rxfrag[i]);
                        ni->ni_rxfrag[i] = NULL;
                }
        /*
         * Must be careful here to remove any key map entry w/o a LOR.
         */
        ieee80211_node_delucastkey(ni);
#undef N
}

static void
node_free(struct ieee80211_node *ni)
{
        struct ieee80211com *ic = ni->ni_ic;

        ic->ic_node_cleanup(ni);
        if (ni->ni_wpa_ie != NULL)
                free(ni->ni_wpa_ie, M_DEVBUF);
        if (ni->ni_wme_ie != NULL)
                free(ni->ni_wme_ie, M_DEVBUF);
        IEEE80211_NODE_SAVEQ_DESTROY(ni);
        free(ni, M_80211_NODE);
}

static uint8_t
node_getrssi(const struct ieee80211_node *ni)
{
        return ni->ni_rssi;
}

static void
ieee80211_setup_node(struct ieee80211_node_table *nt,
        struct ieee80211_node *ni, const uint8_t *macaddr)
{
        struct ieee80211com *ic = nt->nt_ic;
        int hash;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
                "%6D %p<%s> in %s table\n", __func__, ni,
                macaddr, ":", nt->nt_name);

        IEEE80211_ADDR_COPY(ni->ni_macaddr, macaddr);
        hash = IEEE80211_NODE_HASH(macaddr);
        ieee80211_node_initref(ni);             /* mark referenced */
        ni->ni_chan = IEEE80211_CHAN_ANYC;
        ni->ni_authmode = IEEE80211_AUTH_OPEN;
        ni->ni_txpower = ic->ic_txpowlimit;     /* max power */
        ieee80211_crypto_resetkey(ic, &ni->ni_ucastkey, IEEE80211_KEYIX_NONE);
        ni->ni_inact_reload = nt->nt_inact_init;
        ni->ni_inact = ni->ni_inact_reload;
        IEEE80211_NODE_SAVEQ_INIT(ni, "unknown");

        TAILQ_INSERT_TAIL(&nt->nt_node, ni, ni_list);
        LIST_INSERT_HEAD(&nt->nt_hash[hash], ni, ni_hash);
        ni->ni_table = nt;
        ni->ni_ic = ic;
}

struct ieee80211_node *
ieee80211_alloc_node(struct ieee80211_node_table *nt, const uint8_t *macaddr)
{
        struct ieee80211com *ic = nt->nt_ic;
        struct ieee80211_node *ni;

        ni = ic->ic_node_alloc(nt);
        if (ni != NULL)
                ieee80211_setup_node(nt, ni, macaddr);
        else
                ic->ic_stats.is_rx_nodealloc++;
        return ni;
}

/*
 * Craft a temporary node suitable for sending a management frame
 * to the specified station.  We craft only as much state as we
 * need to do the work since the node will be immediately reclaimed
 * once the send completes.
 */
struct ieee80211_node *
ieee80211_tmp_node(struct ieee80211com *ic, const uint8_t *macaddr)
{
        struct ieee80211_node *ni;

        ni = ic->ic_node_alloc(&ic->ic_sta);
        if (ni != NULL) {
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
                        "%s %p<%6D>\n", __func__, ni, macaddr, ":");

                IEEE80211_ADDR_COPY(ni->ni_macaddr, macaddr);
                IEEE80211_ADDR_COPY(ni->ni_bssid, ic->ic_bss->ni_bssid);
                ieee80211_node_initref(ni);             /* mark referenced */
                ni->ni_txpower = ic->ic_bss->ni_txpower;
                /* NB: required by ieee80211_fix_rate */
                ieee80211_set_chan(ic, ni, ic->ic_bss->ni_chan);
                ieee80211_crypto_resetkey(ic, &ni->ni_ucastkey,
                        IEEE80211_KEYIX_NONE);
                /* XXX optimize away */
                IEEE80211_NODE_SAVEQ_INIT(ni, "unknown");

                ni->ni_table = NULL;            /* NB: pedantic */
                ni->ni_ic = ic;
        } else {
                /* XXX msg */
                ic->ic_stats.is_rx_nodealloc++;
        }
        return ni;
}

struct ieee80211_node *
ieee80211_dup_bss(struct ieee80211_node_table *nt, const uint8_t *macaddr)
{
        struct ieee80211com *ic = nt->nt_ic;
        struct ieee80211_node *ni;

        ni = ic->ic_node_alloc(nt);
        if (ni != NULL) {
                ieee80211_setup_node(nt, ni, macaddr);
                /*
                 * Inherit from ic_bss.
                 */
                ni->ni_authmode = ic->ic_bss->ni_authmode;
                ni->ni_txpower = ic->ic_bss->ni_txpower;
                ni->ni_vlan = ic->ic_bss->ni_vlan;      /* XXX?? */
                IEEE80211_ADDR_COPY(ni->ni_bssid, ic->ic_bss->ni_bssid);
                ieee80211_set_chan(ic, ni, ic->ic_bss->ni_chan);
                ni->ni_rsn = ic->ic_bss->ni_rsn;
        } else
                ic->ic_stats.is_rx_nodealloc++;
        return ni;
}

static struct ieee80211_node *
#ifdef IEEE80211_DEBUG_REFCNT
_ieee80211_find_node_debug(struct ieee80211_node_table *nt,
        const uint8_t *macaddr, const char *func, int line)
#else
_ieee80211_find_node(struct ieee80211_node_table *nt,
        const uint8_t *macaddr)
#endif
{
        struct ieee80211_node *ni;
        int hash;

        hash = IEEE80211_NODE_HASH(macaddr);
        LIST_FOREACH(ni, &nt->nt_hash[hash], ni_hash) {
                if (IEEE80211_ADDR_EQ(ni->ni_macaddr, macaddr)) {
                        ieee80211_ref_node(ni); /* mark referenced */
#ifdef IEEE80211_DEBUG_REFCNT
                        IEEE80211_DPRINTF(nt->nt_ic, IEEE80211_MSG_NODE,
                            "%s (%s:%u) %p<%6D> refcnt %d\n", __func__,
                            func, line,
                            ni, ni->ni_macaddr, ":",
                            ieee80211_node_refcnt(ni));
#endif
                        return ni;
                }
        }
        return NULL;
}
#ifdef IEEE80211_DEBUG_REFCNT
#define _ieee80211_find_node(nt, mac) \
        _ieee80211_find_node_debug(nt, mac, func, line)
#endif

struct ieee80211_node *
#ifdef IEEE80211_DEBUG_REFCNT
ieee80211_find_node_debug(struct ieee80211_node_table *nt,
        const uint8_t *macaddr, const char *func, int line)
#else
ieee80211_find_node(struct ieee80211_node_table *nt, const uint8_t *macaddr)
#endif
{
        struct ieee80211_node *ni;

        ASSERT_SERIALIZED(nt->nt_ic->ic_ifp->if_serializer);

        ni = _ieee80211_find_node(nt, macaddr);
        return ni;
}

/*
 * Fake up a node; this handles node discovery in adhoc mode.
 * Note that for the driver's benefit we we treat this like
 * an association so the driver has an opportunity to setup
 * it's private state.
 */
struct ieee80211_node *
ieee80211_fakeup_adhoc_node(struct ieee80211_node_table *nt,
        const uint8_t macaddr[IEEE80211_ADDR_LEN])
{
        struct ieee80211com *ic = nt->nt_ic;
        struct ieee80211_node *ni;

        IEEE80211_DPRINTF(nt->nt_ic, IEEE80211_MSG_NODE,
            "%s: mac<%6D>\n", __func__, macaddr, ":");
        ni = ieee80211_dup_bss(nt, macaddr);
        if (ni != NULL) {
                /* XXX no rate negotiation; just dup */
                ni->ni_rates = ic->ic_bss->ni_rates;
                if (ic->ic_newassoc != NULL)
                        ic->ic_newassoc(ni, 1);
                /* XXX not right for 802.1x/WPA */
                ieee80211_node_authorize(ni);
                if (ic->ic_opmode == IEEE80211_M_AHDEMO) {
                        /*
                         * Blindly propagate capabilities based on the
                         * local configuration.  In particular this permits
                         * us to use QoS to disable ACK's.
                         */
                        if (ic->ic_flags & IEEE80211_F_WME)
                                ni->ni_flags |= IEEE80211_NODE_QOS;
                }
        }
        return ni;
}

#ifdef IEEE80211_DEBUG
static void
dump_probe_beacon(uint8_t subtype, int isnew,
        const uint8_t mac[IEEE80211_ADDR_LEN],
        const struct ieee80211_scanparams *sp)
{

        printf("[%6D] %s%s on chan %u (bss chan %u) ",
            mac, ":", isnew ? "new " : "",
            ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT],
            sp->chan, sp->bchan);
        ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
        printf("\n");

        if (isnew) {
                printf("[%6D] caps 0x%x bintval %u erp 0x%x", 
                        mac, ":", sp->capinfo, sp->bintval, sp->erp);
                if (sp->country != NULL) {
#if defined(__FreeBSD__) || defined(__DragonFly__)
                        printf(" country info %*D",
                                sp->country[1], sp->country+2, " ");
#else
                        int i;
                        printf(" country info");
                        for (i = 0; i < sp->country[1]; i++)
                                printf(" %02x", sp->country[i+2]);
#endif
                }
                printf("\n");
        }
}
#endif /* IEEE80211_DEBUG */

static void
saveie(uint8_t **iep, const uint8_t *ie)
{

        if (ie == NULL)
                *iep = NULL;
        else
                ieee80211_saveie(iep, ie);
}

/*
 * Process a beacon or probe response frame.
 */
void
ieee80211_add_scan(struct ieee80211com *ic,
        const struct ieee80211_scanparams *sp,
        const struct ieee80211_frame *wh,
        int subtype, int rssi, int rstamp)
{
#define ISPROBE(_st)    ((_st) == IEEE80211_FC0_SUBTYPE_PROBE_RESP)
        struct ieee80211_node_table *nt = &ic->ic_scan;
        struct ieee80211_node *ni;
        int newnode = 0;

        ni = ieee80211_find_node(nt, wh->i_addr2);
        if (ni == NULL) {
                /*
                 * Create a new entry.
                 */
                ni = ic->ic_node_alloc(nt);
                if (ni == NULL) {
                        ic->ic_stats.is_rx_nodealloc++;
                        return;
                }
                ieee80211_setup_node(nt, ni, wh->i_addr2);
                /*
                 * XXX inherit from ic_bss.
                 */
                ni->ni_authmode = ic->ic_bss->ni_authmode;
                ni->ni_txpower = ic->ic_bss->ni_txpower;
                ni->ni_vlan = ic->ic_bss->ni_vlan;      /* XXX?? */
                ieee80211_set_chan(ic, ni, ic->ic_curchan);
                ni->ni_rsn = ic->ic_bss->ni_rsn;
                newnode = 1;
        }
#ifdef IEEE80211_DEBUG
        if (ieee80211_msg_scan(ic) && (ic->ic_flags & IEEE80211_F_SCAN))
                dump_probe_beacon(subtype, newnode, wh->i_addr2, sp);
#endif
        /* XXX ap beaconing multiple ssid w/ same bssid */
        if (sp->ssid[1] != 0 &&
            (ISPROBE(subtype) || ni->ni_esslen == 0)) {
                ni->ni_esslen = sp->ssid[1];
                memset(ni->ni_essid, 0, sizeof(ni->ni_essid));
                memcpy(ni->ni_essid, sp->ssid + 2, sp->ssid[1]);
        }
        IEEE80211_ADDR_COPY(ni->ni_bssid, wh->i_addr3);
        ni->ni_rssi = rssi;
        ni->ni_rstamp = rstamp;
        memcpy(ni->ni_tstamp.data, sp->tstamp, sizeof(ni->ni_tstamp));
        ni->ni_intval = sp->bintval;
        ni->ni_capinfo = sp->capinfo;
        ni->ni_chan = &ic->ic_channels[sp->chan];
        ni->ni_fhdwell = sp->fhdwell;
        ni->ni_fhindex = sp->fhindex;
        ni->ni_erp = sp->erp;
        if (sp->tim != NULL) {
                struct ieee80211_tim_ie *ie =
                    (struct ieee80211_tim_ie *) sp->tim;

                ni->ni_dtim_count = ie->tim_count;
                ni->ni_dtim_period = ie->tim_period;
        }
        /*
         * Record the byte offset from the mac header to
         * the start of the TIM information element for
         * use by hardware and/or to speedup software
         * processing of beacon frames.
         */
        ni->ni_timoff = sp->timoff;
        /*
         * Record optional information elements that might be
         * used by applications or drivers.
         */
        saveie(&ni->ni_wme_ie, sp->wme);
        saveie(&ni->ni_wpa_ie, sp->wpa);

        /* NB: must be after ni_chan is setup */
        ieee80211_setup_rates(ni, sp->rates, sp->xrates, IEEE80211_F_DOSORT);

        if (!newnode)
                ieee80211_free_node(ni);
#undef ISPROBE
}

void
ieee80211_init_neighbor(struct ieee80211_node *ni,
        const struct ieee80211_frame *wh,
        const struct ieee80211_scanparams *sp)
{

        IEEE80211_DPRINTF(ni->ni_ic, IEEE80211_MSG_NODE,
            "%s: %p<%s>\n", __func__, ni, ni->ni_macaddr, ":");
        ni->ni_esslen = sp->ssid[1];
        memcpy(ni->ni_essid, sp->ssid + 2, sp->ssid[1]);
        IEEE80211_ADDR_COPY(ni->ni_bssid, wh->i_addr3);
        memcpy(ni->ni_tstamp.data, sp->tstamp, sizeof(ni->ni_tstamp));
        ni->ni_intval = sp->bintval;
        ni->ni_capinfo = sp->capinfo;
        ni->ni_chan = ni->ni_ic->ic_curchan;
        ni->ni_fhdwell = sp->fhdwell;
        ni->ni_fhindex = sp->fhindex;
        ni->ni_erp = sp->erp;
        ni->ni_timoff = sp->timoff;
        if (sp->wme != NULL)
                ieee80211_saveie(&ni->ni_wme_ie, sp->wme);
        if (sp->wpa != NULL)
                ieee80211_saveie(&ni->ni_wpa_ie, sp->wpa);

        /* NB: must be after ni_chan is setup */
        ieee80211_setup_rates(ni, sp->rates, sp->xrates, IEEE80211_F_DOSORT);
}

/*
 * Do node discovery in adhoc mode on receipt of a beacon
 * or probe response frame.  Note that for the driver's
 * benefit we we treat this like an association so the
 * driver has an opportunity to setup it's private state.
 */
struct ieee80211_node *
ieee80211_add_neighbor(struct ieee80211com *ic,
        const struct ieee80211_frame *wh,
        const struct ieee80211_scanparams *sp)
{
        struct ieee80211_node *ni;

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
            "%s: mac<%s>\n", __func__, wh->i_addr2, ":");
        ni = ieee80211_dup_bss(&ic->ic_sta, wh->i_addr2);/* XXX alloc_node? */
        if (ni != NULL) {
                ieee80211_init_neighbor(ni, wh, sp);
                if (ic->ic_newassoc != NULL)
                        ic->ic_newassoc(ni, 1);
                /* XXX not right for 802.1x/WPA */
                ieee80211_node_authorize(ni);
        }
        return ni;
}

#define IS_CTL(wh) \
        ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_CTL)
#define IS_PSPOLL(wh) \
        ((wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK) == IEEE80211_FC0_SUBTYPE_PS_POLL)
/*
 * Locate the node for sender, track state, and then pass the
 * (referenced) node up to the 802.11 layer for its use.  We
 * are required to pass some node so we fall back to ic_bss
 * when this frame is from an unknown sender.  The 802.11 layer
 * knows this means the sender wasn't in the node table and
 * acts accordingly. 
 */
struct ieee80211_node *
#ifdef IEEE80211_DEBUG_REFCNT
ieee80211_find_rxnode_debug(struct ieee80211com *ic,
        const struct ieee80211_frame_min *wh, const char *func, int line)
#else
ieee80211_find_rxnode(struct ieee80211com *ic,
        const struct ieee80211_frame_min *wh)
#endif
{
        struct ieee80211_node_table *nt;
        struct ieee80211_node *ni;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        /* XXX may want scanned nodes in the neighbor table for adhoc */
        if (ic->ic_opmode == IEEE80211_M_STA ||
            ic->ic_opmode == IEEE80211_M_MONITOR ||
            (ic->ic_flags & IEEE80211_F_SCAN))
                nt = &ic->ic_scan;
        else
                nt = &ic->ic_sta;
        /* XXX check ic_bss first in station mode */
        /* XXX 4-address frames? */
        if (IS_CTL(wh) && !IS_PSPOLL(wh) /*&& !IS_RTS(ah)*/)
                ni = _ieee80211_find_node(nt, wh->i_addr1);
        else
                ni = _ieee80211_find_node(nt, wh->i_addr2);
        if (ni == NULL)
                ni = ieee80211_ref_node(ic->ic_bss);

        return ni;
}

/*
 * Like ieee80211_find_rxnode but use the supplied h/w
 * key index as a hint to locate the node in the key
 * mapping table.  If an entry is present at the key
 * index we return it; otherwise do a normal lookup and
 * update the mapping table if the station has a unicast
 * key assigned to it.
 */
struct ieee80211_node *
#ifdef IEEE80211_DEBUG_REFCNT
ieee80211_find_rxnode_withkey_debug(struct ieee80211com *ic,
        const struct ieee80211_frame_min *wh, ieee80211_keyix keyix,
        const char *func, int line)
#else
ieee80211_find_rxnode_withkey(struct ieee80211com *ic,
        const struct ieee80211_frame_min *wh, ieee80211_keyix keyix)
#endif
{
        struct ieee80211_node_table *nt;
        struct ieee80211_node *ni;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        if (ic->ic_opmode == IEEE80211_M_STA ||
            ic->ic_opmode == IEEE80211_M_MONITOR ||
            (ic->ic_flags & IEEE80211_F_SCAN))
                nt = &ic->ic_scan;
        else
                nt = &ic->ic_sta;
        if (nt->nt_keyixmap != NULL && keyix < nt->nt_keyixmax)
                ni = nt->nt_keyixmap[keyix];
        else
                ni = NULL;
        if (ni == NULL) {
                if (IS_CTL(wh) && !IS_PSPOLL(wh) /*&& !IS_RTS(ah)*/)
                        ni = _ieee80211_find_node(nt, wh->i_addr1);
                else
                        ni = _ieee80211_find_node(nt, wh->i_addr2);
                if (ni == NULL)
                        ni = ieee80211_ref_node(ic->ic_bss);
                if (nt->nt_keyixmap != NULL) {
                        /*
                         * If the station has a unicast key cache slot
                         * assigned update the key->node mapping table.
                         */
                        keyix = ni->ni_ucastkey.wk_rxkeyix;
                        /* XXX can keyixmap[keyix] != NULL? */
                        if (keyix < nt->nt_keyixmax &&
                            nt->nt_keyixmap[keyix] == NULL) {
                                IEEE80211_DPRINTF(ni->ni_ic, IEEE80211_MSG_NODE,
                                    "%s: add key map entry %p<%6D> refcnt %d\n",
                                    __func__, ni, ni->ni_macaddr, ":",
                                    ieee80211_node_refcnt(ni)+1);
                                nt->nt_keyixmap[keyix] = ieee80211_ref_node(ni);
                        }
                }
        } else {
                ieee80211_ref_node(ni);
        }

        return ni;
}
#undef IS_PSPOLL
#undef IS_CTL

/*
 * Return a reference to the appropriate node for sending
 * a data frame.  This handles node discovery in adhoc networks.
 */
struct ieee80211_node *
#ifdef IEEE80211_DEBUG_REFCNT
ieee80211_find_txnode_debug(struct ieee80211com *ic, const uint8_t *macaddr,
        const char *func, int line)
#else
ieee80211_find_txnode(struct ieee80211com *ic, const uint8_t *macaddr)
#endif
{
        struct ieee80211_node_table *nt = &ic->ic_sta;
        struct ieee80211_node *ni;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        /*
         * The destination address should be in the node table
         * unless this is a multicast/broadcast frame.  We can
         * also optimize station mode operation, all frames go
         * to the bss node.
         */
        if (ic->ic_opmode == IEEE80211_M_STA || IEEE80211_IS_MULTICAST(macaddr))
                ni = ieee80211_ref_node(ic->ic_bss);
        else
                ni = _ieee80211_find_node(nt, macaddr);

        if (ni == NULL) {
                if (ic->ic_opmode == IEEE80211_M_IBSS ||
                    ic->ic_opmode == IEEE80211_M_AHDEMO) {
                        /*
                         * In adhoc mode cons up a node for the destination.
                         * Note that we need an additional reference for the
                         * caller to be consistent with _ieee80211_find_node.
                         */
                        ni = ieee80211_fakeup_adhoc_node(nt, macaddr);
                        if (ni != NULL)
                                ieee80211_ref_node(ni);
                } else {
                        IEEE80211_DPRINTF(ic, IEEE80211_MSG_OUTPUT,
                                "[%6D] no node, discard frame (%s)\n",
                                macaddr, ":", __func__);
                        ic->ic_stats.is_tx_nonode++;
                }
        }
        return ni;
}

/*
 * Like find but search based on the channel too.
 */
struct ieee80211_node *
#ifdef IEEE80211_DEBUG_REFCNT
ieee80211_find_node_with_channel_debug(struct ieee80211_node_table *nt,
        const uint8_t *macaddr, struct ieee80211_channel *chan,
        const char *func, int line)
#else
ieee80211_find_node_with_channel(struct ieee80211_node_table *nt,
        const uint8_t *macaddr, struct ieee80211_channel *chan)
#endif
{
        struct ieee80211_node *ni;
        int hash;

        ASSERT_SERIALIZED(nt->nt_ic->ic_ifp->if_serializer);

        hash = IEEE80211_NODE_HASH(macaddr);
        LIST_FOREACH(ni, &nt->nt_hash[hash], ni_hash) {
                if (IEEE80211_ADDR_EQ(ni->ni_macaddr, macaddr) &&
                    ni->ni_chan == chan) {
                        ieee80211_ref_node(ni);         /* mark referenced */
                        IEEE80211_DPRINTF(nt->nt_ic, IEEE80211_MSG_NODE,
#ifdef IEEE80211_DEBUG_REFCNT
                            "%s (%s:%u) %p<%6D> refcnt %d\n", __func__,
                            func, line,
#else
                            "%s %p<%6D> refcnt %d\n", __func__,
#endif
                            ni, ni->ni_macaddr, ":",
                            ieee80211_node_refcnt(ni));
                        break;
                }
        }
        return ni;
}

/*
 * Like find but search based on the ssid too.
 */
struct ieee80211_node *
#ifdef IEEE80211_DEBUG_REFCNT
ieee80211_find_node_with_ssid_debug(struct ieee80211_node_table *nt,
        const uint8_t *macaddr, u_int ssidlen, const uint8_t *ssid,
        const char *func, int line)
#else
ieee80211_find_node_with_ssid(struct ieee80211_node_table *nt,
        const uint8_t *macaddr, u_int ssidlen, const uint8_t *ssid)
#endif
{
#define MATCH_SSID(ni, ssid, ssidlen) \
        (ni->ni_esslen == ssidlen && memcmp(ni->ni_essid, ssid, ssidlen) == 0)
        static const uint8_t zeromac[IEEE80211_ADDR_LEN];
        struct ieee80211com *ic = nt->nt_ic;
        struct ieee80211_node *ni;
        int hash;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        /*
         * A mac address that is all zero means match only the ssid;
         * otherwise we must match both.
         */
        if (IEEE80211_ADDR_EQ(macaddr, zeromac)) {
                TAILQ_FOREACH(ni, &nt->nt_node, ni_list) {
                        if (MATCH_SSID(ni, ssid, ssidlen))
                                break;
                }
        } else {
                hash = IEEE80211_NODE_HASH(macaddr);
                LIST_FOREACH(ni, &nt->nt_hash[hash], ni_hash) {
                        if (IEEE80211_ADDR_EQ(ni->ni_macaddr, macaddr) &&
                            MATCH_SSID(ni, ssid, ssidlen))
                                break;
                }
        }
        if (ni != NULL) {
                ieee80211_ref_node(ni); /* mark referenced */
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
#ifdef IEEE80211_DEBUG_REFCNT
                    "%s (%s:%u) %p<%6D> refcnt %d\n", __func__,
                    func, line,
#else
                    "%s %p<%6D> refcnt %d\n", __func__,
#endif
                     ni, ni->ni_macaddr, ":",
                     ieee80211_node_refcnt(ni));
        }
        return ni;
#undef MATCH_SSID
}

static void
_ieee80211_free_node(struct ieee80211_node *ni)
{
        struct ieee80211com *ic = ni->ni_ic;
        struct ieee80211_node_table *nt = ni->ni_table;

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
                "%s %p<%6D> in %s table\n", __func__, ni,
                ni->ni_macaddr, ":",
                nt != NULL ? nt->nt_name : "<gone>");

        IEEE80211_AID_CLR(ni->ni_associd, ic->ic_aid_bitmap);
        if (nt != NULL) {
                TAILQ_REMOVE(&nt->nt_node, ni, ni_list);
                LIST_REMOVE(ni, ni_hash);
        }
        ic->ic_node_free(ni);
}

void
#ifdef IEEE80211_DEBUG_REFCNT
ieee80211_free_node_debug(struct ieee80211_node *ni, const char *func, int line)
#else
ieee80211_free_node(struct ieee80211_node *ni)
#endif
{
        struct ieee80211_node_table *nt = ni->ni_table;

        ASSERT_SERIALIZED(ni->ni_ic->ic_ifp->if_serializer);

#ifdef IEEE80211_DEBUG_REFCNT
        IEEE80211_DPRINTF(ni->ni_ic, IEEE80211_MSG_NODE,
                "%s (%s:%u) %p<%6D> refcnt %d\n", __func__, func, line, ni,
                 ni->ni_macaddr, ":", ieee80211_node_refcnt(ni) - 1);
#endif
        if (nt != NULL) {
                if (ieee80211_node_dectestref(ni)) {
                        /*
                         * Last reference, reclaim state.
                         */
                        _ieee80211_free_node(ni);
                } else if (ieee80211_node_refcnt(ni) == 1 &&
                    nt->nt_keyixmap != NULL) {
                        ieee80211_keyix keyix;
                        /*
                         * Check for a last reference in the key mapping table.
                         */
                        keyix = ni->ni_ucastkey.wk_rxkeyix;
                        if (keyix < nt->nt_keyixmax &&
                            nt->nt_keyixmap[keyix] == ni) {
                                IEEE80211_DPRINTF(ni->ni_ic, IEEE80211_MSG_NODE,
                                    "%s: %p<%6D> clear key map entry", __func__,
                                    ni, ni->ni_macaddr, ":");
                                nt->nt_keyixmap[keyix] = NULL;
                                ieee80211_node_decref(ni); /* XXX needed? */
                                _ieee80211_free_node(ni);
                        }
                }
        } else {
                if (ieee80211_node_dectestref(ni))
                        _ieee80211_free_node(ni);
        }
}

/*
 * Reclaim a unicast key and clear any key cache state.
 */
int
ieee80211_node_delucastkey(struct ieee80211_node *ni)
{
        struct ieee80211com *ic = ni->ni_ic;
        struct ieee80211_node_table *nt = &ic->ic_sta;
        struct ieee80211_node *nikey;
        ieee80211_keyix keyix;
        int status;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        keyix = ni->ni_ucastkey.wk_rxkeyix;
        status = ieee80211_crypto_delkey(ic, &ni->ni_ucastkey);
        if (nt->nt_keyixmap != NULL && keyix < nt->nt_keyixmax) {
                nikey = nt->nt_keyixmap[keyix];
                nt->nt_keyixmap[keyix] = NULL;;
        } else
                nikey = NULL;

        if (nikey != NULL) {
                KASSERT(nikey == ni,
                        ("key map out of sync, ni %p nikey %p", ni, nikey));
                IEEE80211_DPRINTF(ni->ni_ic, IEEE80211_MSG_NODE,
                        "%s: delete key map entry %p<%6D> refcnt %d\n",
                        __func__, ni, ni->ni_macaddr, ":",
                        ieee80211_node_refcnt(ni)-1);
                ieee80211_free_node(ni);
        }
        return status;
}

/*
 * Reclaim a node.  If this is the last reference count then
 * do the normal free work.  Otherwise remove it from the node
 * table and mark it gone by clearing the back-reference.
 */
static void
node_reclaim(struct ieee80211_node_table *nt, struct ieee80211_node *ni)
{
        ieee80211_keyix keyix;

        ASSERT_SERIALIZED(nt->nt_ic->ic_ifp->if_serializer);

        IEEE80211_DPRINTF(ni->ni_ic, IEEE80211_MSG_NODE,
                "%s: remove %p<%6D> from %s table, refcnt %d\n",
                __func__, ni, ni->ni_macaddr, ":",
                nt->nt_name, ieee80211_node_refcnt(ni)-1);
        /*
         * Clear any entry in the unicast key mapping table.
         * We need to do it here so rx lookups don't find it
         * in the mapping table even if it's not in the hash
         * table.  We cannot depend on the mapping table entry
         * being cleared because the node may not be free'd.
         */
        keyix = ni->ni_ucastkey.wk_rxkeyix;
        if (nt->nt_keyixmap != NULL && keyix < nt->nt_keyixmax &&
            nt->nt_keyixmap[keyix] == ni) {
                IEEE80211_DPRINTF(ni->ni_ic, IEEE80211_MSG_NODE,
                        "%s: %p<%6D> clear key map entry\n",
                        __func__, ni, ni->ni_macaddr, ":");
                nt->nt_keyixmap[keyix] = NULL;
                ieee80211_node_decref(ni);      /* NB: don't need free */
        }
        if (!ieee80211_node_dectestref(ni)) {
                /*
                 * Other references are present, just remove the
                 * node from the table so it cannot be found.  When
                 * the references are dropped storage will be
                 * reclaimed.
                 */
                TAILQ_REMOVE(&nt->nt_node, ni, ni_list);
                LIST_REMOVE(ni, ni_hash);
                ni->ni_table = NULL;            /* clear reference */
        } else
                _ieee80211_free_node(ni);
}

static void
ieee80211_free_allnodes(struct ieee80211_node_table *nt)
{
        struct ieee80211com *ic = nt->nt_ic;
        struct ieee80211_node *ni;

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
                "%s: free all nodes in %s table\n", __func__, nt->nt_name);

        while ((ni = TAILQ_FIRST(&nt->nt_node)) != NULL) {
                if (ni->ni_associd != 0) {
                        if (ic->ic_auth->ia_node_leave != NULL)
                                ic->ic_auth->ia_node_leave(ic, ni);
                        IEEE80211_AID_CLR(ni->ni_associd, ic->ic_aid_bitmap);
                }
                node_reclaim(nt, ni);
        }
        ieee80211_reset_erp(ic);
}

/*
 * Timeout entries in the scan cache.
 */
static void
ieee80211_timeout_scan_candidates(struct ieee80211_node_table *nt)
{
        struct ieee80211com *ic = nt->nt_ic;
        struct ieee80211_node *ni, *tni;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        ni = ic->ic_bss;
        /* XXX belongs elsewhere */
        if (ni->ni_rxfrag[0] != NULL && ticks > ni->ni_rxfragstamp + hz) {
                m_freem(ni->ni_rxfrag[0]);
                ni->ni_rxfrag[0] = NULL;
        }
        TAILQ_FOREACH_MUTABLE(ni, &nt->nt_node, ni_list, tni) {
                if (ni->ni_inact && --ni->ni_inact == 0) {
                        IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
                            "[%6D] scan candidate purged from cache "
                            "(refcnt %u)\n", ni->ni_macaddr, ":",
                            ieee80211_node_refcnt(ni));
                        node_reclaim(nt, ni);
                }
        }

        nt->nt_inact_timer = IEEE80211_INACT_WAIT;
}

/*
 * Timeout inactive stations and do related housekeeping.
 * Note that we cannot hold the node lock while sending a
 * frame as this would lead to a LOR.  Instead we use a
 * generation number to mark nodes that we've scanned and
 * drop the lock and restart a scan if we have to time out
 * a node.  Since we are single-threaded by virtue of
 * controlling the inactivity timer we can be sure this will
 * process each node only once.
 */
static void
ieee80211_timeout_stations(struct ieee80211_node_table *nt)
{
        struct ieee80211com *ic = nt->nt_ic;
        struct ieee80211_node *ni, *next;
        int isadhoc;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        isadhoc = (ic->ic_opmode == IEEE80211_M_IBSS ||
                   ic->ic_opmode == IEEE80211_M_AHDEMO);

        TAILQ_FOREACH_MUTABLE(ni, &nt->nt_node, ni_list, next) {
                /*
                 * Ignore entries for which have yet to receive an
                 * authentication frame.  These are transient and
                 * will be reclaimed when the last reference to them
                 * goes away (when frame xmits complete).
                 */
                if (ic->ic_opmode == IEEE80211_M_HOSTAP &&
                    (ni->ni_flags & IEEE80211_NODE_AREF) == 0)
                        continue;
                /*
                 * Free fragment if not needed anymore
                 * (last fragment older than 1s).
                 * XXX doesn't belong here
                 */
                if (ni->ni_rxfrag[0] != NULL &&
                    ticks > ni->ni_rxfragstamp + hz) {
                        m_freem(ni->ni_rxfrag[0]);
                        ni->ni_rxfrag[0] = NULL;
                }
                /*
                 * Special case ourself; we may be idle for extended periods
                 * of time and regardless reclaiming our state is wrong.
                 */
                if (ni == ic->ic_bss)
                        continue;
                ni->ni_inact--;
                if (ni->ni_associd != 0 || isadhoc) {
                        /*
                         * Age frames on the power save queue. The
                         * aging interval is 4 times the listen
                         * interval specified by the station.  This
                         * number is factored into the age calculations
                         * when the frame is placed on the queue.  We
                         * store ages as time differences we can check
                         * and/or adjust only the head of the list.
                         */
                        if (IEEE80211_NODE_SAVEQ_QLEN(ni) != 0) {
                                struct mbuf *m;
                                int discard = 0;

                                while (IF_POLL(&ni->ni_savedq, m) != NULL &&
                                     M_AGE_GET(m) < IEEE80211_INACT_WAIT) {
                                        IEEE80211_DPRINTF(ic,
                                            IEEE80211_MSG_POWER,
                                            "[%6D] discard frame, age %u\n",
                                            ni->ni_macaddr, ":",
                                            M_AGE_GET(m));/*XXX*/
                                        _IEEE80211_NODE_SAVEQ_DEQUEUE_HEAD(ni, m);
                                        m_freem(m);
                                        discard++;
                                }
                                if (m != NULL)
                                        M_AGE_SUB(m, IEEE80211_INACT_WAIT);

                                if (discard != 0) {
                                        IEEE80211_DPRINTF(ic,
                                            IEEE80211_MSG_POWER,
                                            "[%6D] discard %u frames for age\n",
                                            ni->ni_macaddr, ":",
                                            discard);
                                        IEEE80211_NODE_STAT_ADD(ni,
                                                ps_discard, discard);
                                        if (IEEE80211_NODE_SAVEQ_QLEN(ni) == 0)
                                                ic->ic_set_tim(ni, 0);
                                }
                        }
                        /*
                         * Probe the station before time it out.  We
                         * send a null data frame which may not be
                         * universally supported by drivers (need it
                         * for ps-poll support so it should be...).
                         */
                        if (0 < ni->ni_inact &&
                            ni->ni_inact <= ic->ic_inact_probe) {
                                IEEE80211_NOTE(ic,
                                    IEEE80211_MSG_INACT | IEEE80211_MSG_NODE,
                                    ni, "%s",
                                    "probe station due to inactivity");
                                /*
                                 * Grab a reference before unlocking the table
                                 * so the node cannot be reclaimed before we
                                 * send the frame. ieee80211_send_nulldata
                                 * understands we've done this and reclaims the
                                 * ref for us as needed.
                                 */
                                ieee80211_ref_node(ni);
                                ieee80211_send_nulldata(ni);
                                /* XXX stat? */
                                continue;
                        }
                }
                if (ni->ni_inact <= 0) {
                        IEEE80211_NOTE(ic,
                            IEEE80211_MSG_INACT | IEEE80211_MSG_NODE, ni,
                            "station timed out due to inactivity "
                            "(refcnt %u)", ieee80211_node_refcnt(ni));
                        /*
                         * Send a deauthenticate frame and drop the station.
                         * This is somewhat complicated due to reference counts
                         * and locking.  At this point a station will typically
                         * have a reference count of 1.  ieee80211_node_leave
                         * will do a "free" of the node which will drop the
                         * reference count.  But in the meantime a reference
                         * wil be held by the deauth frame.  The actual reclaim
                         * of the node will happen either after the tx is
                         * completed or by ieee80211_node_leave.
                         */
                        if (ni->ni_associd != 0) {
                                IEEE80211_SEND_MGMT(ic, ni,
                                    IEEE80211_FC0_SUBTYPE_DEAUTH,
                                    IEEE80211_REASON_AUTH_EXPIRE);
                        }
                        ieee80211_node_leave(ic, ni);
                        ic->ic_stats.is_node_timeout++;
                        continue;
                }
        }

        nt->nt_inact_timer = IEEE80211_INACT_WAIT;
}

void
ieee80211_iterate_nodes(struct ieee80211_node_table *nt, ieee80211_iter_func *f, void *arg)
{
        struct ieee80211_node *ni, *next;

        ASSERT_SERIALIZED(nt->nt_ic->ic_ifp->if_serializer);

        TAILQ_FOREACH_MUTABLE(ni, &nt->nt_node, ni_list, next)
                f(arg, ni);
}

void
ieee80211_dump_node(struct ieee80211_node_table *nt, struct ieee80211_node *ni)
{
        printf("0x%p: mac %6D refcnt %d\n", ni,
                ni->ni_macaddr, ":", ieee80211_node_refcnt(ni));
        printf("\tauthmode %u flags 0x%x\n",
                ni->ni_authmode, ni->ni_flags);
        printf("\tassocid 0x%x txpower %u vlan %u\n",
                ni->ni_associd, ni->ni_txpower, ni->ni_vlan);
        printf("\ttxseq %u rxseq %u fragno %u rxfragstamp %u\n",
                ni->ni_txseqs[0],
                ni->ni_rxseqs[0] >> IEEE80211_SEQ_SEQ_SHIFT,
                ni->ni_rxseqs[0] & IEEE80211_SEQ_FRAG_MASK,
                ni->ni_rxfragstamp);
        printf("\trstamp %u rssi %u intval %u capinfo 0x%x\n",
                ni->ni_rstamp, ni->ni_rssi, ni->ni_intval, ni->ni_capinfo);
        printf("\tbssid %6D essid \"%.*s\" channel %u:0x%x\n",
                ni->ni_bssid, ":",
                ni->ni_esslen, ni->ni_essid,
                ni->ni_chan->ic_freq, ni->ni_chan->ic_flags);
        printf("\tfails %u inact %u txrate %u\n",
                ni->ni_fails, ni->ni_inact, ni->ni_txrate);
}

void
ieee80211_dump_nodes(struct ieee80211_node_table *nt)
{
        ieee80211_iterate_nodes(nt,
                (ieee80211_iter_func *) ieee80211_dump_node, nt);
}

/*
 * Handle a station joining an 11g network.
 */
static void
ieee80211_node_join_11g(struct ieee80211com *ic, struct ieee80211_node *ni)
{

        /*
         * Station isn't capable of short slot time.  Bump
         * the count of long slot time stations and disable
         * use of short slot time.  Note that the actual switch
         * over to long slot time use may not occur until the
         * next beacon transmission (per sec. 7.3.1.4 of 11g).
         */
        if ((ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_SLOTTIME) == 0) {
                ic->ic_longslotsta++;
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                    "[%6D] station needs long slot time, count %d\n",
                    ni->ni_macaddr, ":", ic->ic_longslotsta);
                /* XXX vap's w/ conflicting needs won't work */
                ieee80211_set_shortslottime(ic, 0);
        }
        /*
         * If the new station is not an ERP station
         * then bump the counter and enable protection
         * if configured.
         */
        if (!ieee80211_iserp_rateset(ic, &ni->ni_rates)) {
                ic->ic_nonerpsta++;
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                    "[%6D] station is !ERP, %d non-ERP stations associated\n",
                    ni->ni_macaddr, ":", ic->ic_nonerpsta);
                /*
                 * If protection is configured, enable it.
                 */
                if (ic->ic_protmode != IEEE80211_PROT_NONE) {
                        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                            "%s: enable use of protection\n", __func__);
                        ic->ic_flags |= IEEE80211_F_USEPROT;
                }
                /*
                 * If station does not support short preamble
                 * then we must enable use of Barker preamble.
                 */
                if ((ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_PREAMBLE) == 0) {
                        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                            "[%6D] station needs long preamble\n",
                            ni->ni_macaddr, ":");
                        ic->ic_flags |= IEEE80211_F_USEBARKER;
                        ic->ic_flags &= ~IEEE80211_F_SHPREAMBLE;
                }
                if (ic->ic_nonerpsta == 1)
                        ic->ic_flags_ext |= IEEE80211_FEXT_ERPUPDATE;
        } else
                ni->ni_flags |= IEEE80211_NODE_ERP;
}

void
ieee80211_node_join(struct ieee80211com *ic, struct ieee80211_node *ni, int resp)
{
        int newassoc;

        if (ni->ni_associd == 0) {
                uint16_t aid;

                /*
                 * It would be good to search the bitmap
                 * more efficiently, but this will do for now.
                 */
                for (aid = 1; aid < ic->ic_max_aid; aid++) {
                        if (!IEEE80211_AID_ISSET(aid,
                            ic->ic_aid_bitmap))
                                break;
                }
                if (aid >= ic->ic_max_aid) {
                        IEEE80211_SEND_MGMT(ic, ni, resp,
                            IEEE80211_REASON_ASSOC_TOOMANY);
                        ieee80211_node_leave(ic, ni);
                        return;
                }
                ni->ni_associd = aid | 0xc000;
                IEEE80211_AID_SET(ni->ni_associd, ic->ic_aid_bitmap);
                ic->ic_sta_assoc++;
                newassoc = 1;
                if (ic->ic_curmode == IEEE80211_MODE_11G)
                        ieee80211_node_join_11g(ic, ni);
        } else
                newassoc = 0;

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC | IEEE80211_MSG_DEBUG,
            "[%6D] station %sassociated at aid %d: %s preamble, %s slot time%s%s\n",
            ni->ni_macaddr, ":", newassoc ? "" : "re",
            IEEE80211_NODE_AID(ni),
            ic->ic_flags & IEEE80211_F_SHPREAMBLE ? "short" : "long",
            ic->ic_flags & IEEE80211_F_SHSLOT ? "short" : "long",
            ic->ic_flags & IEEE80211_F_USEPROT ? ", protection" : "",
            ni->ni_flags & IEEE80211_NODE_QOS ? ", QoS" : ""
        );

        /* give driver a chance to setup state like ni_txrate */
        if (ic->ic_newassoc != NULL)
                ic->ic_newassoc(ni, newassoc);
        ni->ni_inact_reload = ic->ic_inact_auth;
        ni->ni_inact = ni->ni_inact_reload;
        IEEE80211_SEND_MGMT(ic, ni, resp, IEEE80211_STATUS_SUCCESS);
        /* tell the authenticator about new station */
        if (ic->ic_auth->ia_node_join != NULL)
                ic->ic_auth->ia_node_join(ic, ni);
        ieee80211_notify_node_join(ic, ni, newassoc);
}

/*
 * Handle a station leaving an 11g network.
 */
static void
ieee80211_node_leave_11g(struct ieee80211com *ic, struct ieee80211_node *ni)
{

        KASSERT(ic->ic_curmode == IEEE80211_MODE_11G,
             ("not in 11g, bss %u:0x%x, curmode %u", ni->ni_chan->ic_freq,
              ni->ni_chan->ic_flags, ic->ic_curmode));

        /*
         * If a long slot station do the slot time bookkeeping.
         */
        if ((ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_SLOTTIME) == 0) {
                KASSERT(ic->ic_longslotsta > 0,
                    ("bogus long slot station count %d", ic->ic_longslotsta));
                ic->ic_longslotsta--;
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                    "[%6D] long slot time station leaves, count now %d\n",
                    ni->ni_macaddr, ":", ic->ic_longslotsta);
                if (ic->ic_longslotsta == 0) {
                        /*
                         * Re-enable use of short slot time if supported
                         * and not operating in IBSS mode (per spec).
                         */
                        if ((ic->ic_caps & IEEE80211_C_SHSLOT) &&
                            ic->ic_opmode != IEEE80211_M_IBSS) {
                                IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                                    "%s: re-enable use of short slot time\n",
                                    __func__);
                                ieee80211_set_shortslottime(ic, 1);
                        }
                }
        }
        /*
         * If a non-ERP station do the protection-related bookkeeping.
         */
        if ((ni->ni_flags & IEEE80211_NODE_ERP) == 0) {
                KASSERT(ic->ic_nonerpsta > 0,
                    ("bogus non-ERP station count %d", ic->ic_nonerpsta));
                ic->ic_nonerpsta--;
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                    "[%6D] non-ERP station leaves, count now %d\n",
                    ni->ni_macaddr, ":", ic->ic_nonerpsta);
                if (ic->ic_nonerpsta == 0) {
                        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                                "%s: disable use of protection\n", __func__);
                        ic->ic_flags &= ~IEEE80211_F_USEPROT;
                        /* XXX verify mode? */
                        if (ic->ic_caps & IEEE80211_C_SHPREAMBLE) {
                                IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
                                    "%s: re-enable use of short preamble\n",
                                    __func__);
                                ic->ic_flags |= IEEE80211_F_SHPREAMBLE;
                                ic->ic_flags &= ~IEEE80211_F_USEBARKER;
                        }
                        ic->ic_flags_ext |= IEEE80211_FEXT_ERPUPDATE;
                }
        }
}

/*
 * Handle bookkeeping for station deauthentication/disassociation
 * when operating as an ap.
 */
void
ieee80211_node_leave(struct ieee80211com *ic, struct ieee80211_node *ni)
{
        struct ieee80211_node_table *nt = ni->ni_table;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC | IEEE80211_MSG_DEBUG,
            "[%6D] station with aid %d leaves\n",
            ni->ni_macaddr, ":", IEEE80211_NODE_AID(ni));

        KASSERT(ic->ic_opmode == IEEE80211_M_HOSTAP ||
                ic->ic_opmode == IEEE80211_M_IBSS ||
                ic->ic_opmode == IEEE80211_M_AHDEMO,
                ("unexpected operating mode %u", ic->ic_opmode));
        /*
         * If node wasn't previously associated all
         * we need to do is reclaim the reference.
         */
        /* XXX ibss mode bypasses 11g and notification */
        if (ni->ni_associd == 0)
                goto done;
        /*
         * Tell the authenticator the station is leaving.
         * Note that we must do this before yanking the
         * association id as the authenticator uses the
         * associd to locate it's state block.
         */
        if (ic->ic_auth->ia_node_leave != NULL)
                ic->ic_auth->ia_node_leave(ic, ni);
        IEEE80211_AID_CLR(ni->ni_associd, ic->ic_aid_bitmap);
        ni->ni_associd = 0;
        ic->ic_sta_assoc--;

        if (ic->ic_curmode == IEEE80211_MODE_11G)
                ieee80211_node_leave_11g(ic, ni);
        /*
         * Cleanup station state.  In particular clear various
         * state that might otherwise be reused if the node
         * is reused before the reference count goes to zero
         * (and memory is reclaimed).
         */
        ieee80211_sta_leave(ic, ni);
done:
        /*
         * Remove the node from any table it's recorded in and
         * drop the caller's reference.  Removal from the table
         * is important to insure the node is not reprocessed
         * for inactivity.
         */
        if (nt != NULL)
                node_reclaim(nt, ni);
        else
                ieee80211_free_node(ni);
}

uint8_t
ieee80211_getrssi(struct ieee80211com *ic)
{
#define NZ(x)   ((x) == 0 ? 1 : (x))
        struct ieee80211_node_table *nt = &ic->ic_sta;
        uint32_t rssi_samples, rssi_total;
        struct ieee80211_node *ni;

        rssi_total = 0;
        rssi_samples = 0;
        switch (ic->ic_opmode) {
        case IEEE80211_M_IBSS:          /* average of all ibss neighbors */
                /* XXX locking */
                TAILQ_FOREACH(ni, &nt->nt_node, ni_list)
                        if (ni->ni_capinfo & IEEE80211_CAPINFO_IBSS) {
                                rssi_samples++;
                                rssi_total += ic->ic_node_getrssi(ni);
                        }
                break;
        case IEEE80211_M_AHDEMO:        /* average of all neighbors */
                /* XXX locking */
                TAILQ_FOREACH(ni, &nt->nt_node, ni_list) {
                        rssi_samples++;
                        rssi_total += ic->ic_node_getrssi(ni);
                }
                break;
        case IEEE80211_M_HOSTAP:        /* average of all associated stations */
                /* XXX locking */
                TAILQ_FOREACH(ni, &nt->nt_node, ni_list)
                        if (IEEE80211_AID(ni->ni_associd) != 0) {
                                rssi_samples++;
                                rssi_total += ic->ic_node_getrssi(ni);
                        }
                break;
        case IEEE80211_M_MONITOR:       /* XXX */
        case IEEE80211_M_STA:           /* use stats from associated ap */
        default:
                if (ic->ic_bss != NULL)
                        rssi_total = ic->ic_node_getrssi(ic->ic_bss);
                rssi_samples = 1;
                break;
        }
        return rssi_total / NZ(rssi_samples);
#undef NZ
}

/*
 * Indicate whether there are frames queued for a station in power-save mode.
 */
static void
ieee80211_set_tim(struct ieee80211_node *ni, int set)
{
        struct ieee80211com *ic = ni->ni_ic;
        uint16_t aid;

        ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);

        KASSERT(ic->ic_opmode == IEEE80211_M_HOSTAP ||
                ic->ic_opmode == IEEE80211_M_IBSS,
                ("operating mode %u", ic->ic_opmode));

        aid = IEEE80211_AID(ni->ni_associd);
        KASSERT(aid < ic->ic_max_aid,
                ("bogus aid %u, max %u", aid, ic->ic_max_aid));

        if (set != (isset(ic->ic_tim_bitmap, aid) != 0)) {
                if (set) {
                        setbit(ic->ic_tim_bitmap, aid);
                        ic->ic_ps_pending++;
                } else {
                        clrbit(ic->ic_tim_bitmap, aid);
                        ic->ic_ps_pending--;
                }
                ic->ic_flags |= IEEE80211_F_TIMUPDATE;
        }
}

/*
 * Node table support.
 */

static void
ieee80211_node_table_init(struct ieee80211com *ic,
        struct ieee80211_node_table *nt,
        const char *name, int inact, int keyixmax,
        void (*timeout)(struct ieee80211_node_table *))
{
        IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
                "%s %s table, inact %u\n", __func__, name, inact);

        nt->nt_ic = ic;
        TAILQ_INIT(&nt->nt_node);
        nt->nt_name = name;
        nt->nt_inact_init = inact;
        nt->nt_timeout = timeout;
        nt->nt_keyixmax = keyixmax;
        if (nt->nt_keyixmax > 0) {
                nt->nt_keyixmap =
                        malloc(keyixmax * sizeof(struct ieee80211_node *),
                               M_80211_NODE, M_WAITOK | M_ZERO);
        } else {
                nt->nt_keyixmap = NULL;
        }
}

void
ieee80211_node_table_reset(struct ieee80211_node_table *nt)
{
        ASSERT_SERIALIZED(nt->nt_ic->ic_ifp->if_serializer);

        IEEE80211_DPRINTF(nt->nt_ic, IEEE80211_MSG_NODE,
                "%s %s table\n", __func__, nt->nt_name);

        nt->nt_inact_timer = 0;
        ieee80211_free_allnodes(nt);
}

static void
ieee80211_node_table_cleanup(struct ieee80211_node_table *nt)
{
        ASSERT_SERIALIZED(nt->nt_ic->ic_ifp->if_serializer);

        IEEE80211_DPRINTF(nt->nt_ic, IEEE80211_MSG_NODE,
                "%s %s table\n", __func__, nt->nt_name);

        ieee80211_free_allnodes(nt);
        if (nt->nt_keyixmap != NULL) {
                /* XXX verify all entries are NULL */
                int i;
                for (i = 0; i < nt->nt_keyixmax; i++)
                        if (nt->nt_keyixmap[i] != NULL) {
                                printf("%s: %s[%u] still active\n", __func__,
                                       nt->nt_name, i);
                        }
                free(nt->nt_keyixmap, M_80211_NODE);
                nt->nt_keyixmap = NULL;
        }
}