Initial import

Code is based on FreeBSD 8.2 with USB support from Sebastian Huber
and Thomas Doerfler. Initial TCP/IP stack work is from Kevel Kirspel.

1 files changed, 1240 insertions, 0 deletions

diff --git a/rtems/freebsd/net80211/ieee80211_scan.c b/rtems/freebsd/net80211/ieee80211_scan.c
new file mode 100644
index 00000000..3645c19f
--- /dev/null
+++ b/rtems/freebsd/net80211/ieee80211_scan.c
@@ -0,0 +1,1240 @@
+#include <rtems/freebsd/machine/rtems-bsd-config.h>
+
+/*-
+ * Copyright (c) 2002-2008 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.
+ *
+ * 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.
+ */
+
+#include <rtems/freebsd/sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+/*
+ * IEEE 802.11 scanning support.
+ */
+#include <rtems/freebsd/local/opt_wlan.h>
+
+#include <rtems/freebsd/sys/param.h>
+#include <rtems/freebsd/sys/systm.h> 
+#include <rtems/freebsd/sys/proc.h>
+#include <rtems/freebsd/sys/kernel.h>
+#include <rtems/freebsd/sys/condvar.h>
+ 
+#include <rtems/freebsd/sys/socket.h>
+
+#include <rtems/freebsd/net/if.h>
+#include <rtems/freebsd/net/if_media.h>
+#include <rtems/freebsd/net/ethernet.h>
+
+#include <rtems/freebsd/net80211/ieee80211_var.h>
+
+#include <rtems/freebsd/net/bpf.h>
+
+struct scan_state {
+	struct ieee80211_scan_state base;	/* public state */
+
+	u_int		ss_iflags;		/* flags used internally */
+#define	ISCAN_MINDWELL 	0x0001		/* min dwell time reached */
+#define	ISCAN_DISCARD	0x0002		/* discard rx'd frames */
+#define	ISCAN_CANCEL	0x0004		/* cancel current scan */
+#define	ISCAN_ABORT	0x0008		/* end the scan immediately */
+	unsigned long	ss_chanmindwell;	/* min dwell on curchan */
+	unsigned long	ss_scanend;		/* time scan must stop */
+	u_int		ss_duration;		/* duration for next scan */
+	struct task	ss_scan_task;		/* scan execution */
+	struct cv	ss_scan_cv;		/* scan signal */
+	struct callout	ss_scan_timer;		/* scan timer */
+};
+#define	SCAN_PRIVATE(ss)	((struct scan_state *) ss)
+
+/*
+ * Amount of time to go off-channel during a background
+ * scan.  This value should be large enough to catch most
+ * ap's but short enough that we can return on-channel
+ * before our listen interval expires.
+ *
+ * XXX tunable
+ * XXX check against configured listen interval
+ */
+#define	IEEE80211_SCAN_OFFCHANNEL	msecs_to_ticks(150)
+
+/*
+ * Roaming-related defaults.  RSSI thresholds are as returned by the
+ * driver (.5dBm).  Transmit rate thresholds are IEEE rate codes (i.e
+ * .5M units) or MCS.
+ */
+/* rssi thresholds */
+#define	ROAM_RSSI_11A_DEFAULT		14	/* 11a bss */
+#define	ROAM_RSSI_11B_DEFAULT		14	/* 11b bss */
+#define	ROAM_RSSI_11BONLY_DEFAULT	14	/* 11b-only bss */
+/* transmit rate thresholds */
+#define	ROAM_RATE_11A_DEFAULT		2*12	/* 11a bss */
+#define	ROAM_RATE_11B_DEFAULT		2*5	/* 11b bss */
+#define	ROAM_RATE_11BONLY_DEFAULT	2*1	/* 11b-only bss */
+#define	ROAM_RATE_HALF_DEFAULT		2*6	/* half-width 11a/g bss */
+#define	ROAM_RATE_QUARTER_DEFAULT	2*3	/* quarter-width 11a/g bss */
+#define	ROAM_MCS_11N_DEFAULT		(1 | IEEE80211_RATE_MCS) /* 11n bss */
+
+static	void scan_curchan(struct ieee80211_scan_state *, unsigned long);
+static	void scan_mindwell(struct ieee80211_scan_state *);
+static	void scan_signal(void *);
+static	void scan_task(void *, int);
+
+MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
+
+void
+ieee80211_scan_attach(struct ieee80211com *ic)
+{
+	struct scan_state *ss;
+
+	ss = (struct scan_state *) malloc(sizeof(struct scan_state),
+		M_80211_SCAN, M_NOWAIT | M_ZERO);
+	if (ss == NULL) {
+		ic->ic_scan = NULL;
+		return;
+	}
+	callout_init_mtx(&ss->ss_scan_timer, IEEE80211_LOCK_OBJ(ic), 0);
+	cv_init(&ss->ss_scan_cv, "scan");
+	TASK_INIT(&ss->ss_scan_task, 0, scan_task, ss);
+	ic->ic_scan = &ss->base;
+	ss->base.ss_ic = ic;
+
+	ic->ic_scan_curchan = scan_curchan;
+	ic->ic_scan_mindwell = scan_mindwell;
+}
+
+void
+ieee80211_scan_detach(struct ieee80211com *ic)
+{
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+
+	if (ss != NULL) {
+		IEEE80211_LOCK(ic);
+		SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
+		scan_signal(ss);
+		IEEE80211_UNLOCK(ic);
+		ieee80211_draintask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
+		callout_drain(&SCAN_PRIVATE(ss)->ss_scan_timer);
+		KASSERT((ic->ic_flags & IEEE80211_F_SCAN) == 0,
+		    ("scan still running"));
+		if (ss->ss_ops != NULL) {
+			ss->ss_ops->scan_detach(ss);
+			ss->ss_ops = NULL;
+		}
+		ic->ic_scan = NULL;
+		free(SCAN_PRIVATE(ss), M_80211_SCAN);
+	}
+}
+
+static const struct ieee80211_roamparam defroam[IEEE80211_MODE_MAX] = {
+	[IEEE80211_MODE_11A]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
+				    .rate = ROAM_RATE_11A_DEFAULT },
+	[IEEE80211_MODE_11G]	= { .rssi = ROAM_RSSI_11B_DEFAULT,
+				    .rate = ROAM_RATE_11B_DEFAULT },
+	[IEEE80211_MODE_11B]	= { .rssi = ROAM_RSSI_11BONLY_DEFAULT,
+				    .rate = ROAM_RATE_11BONLY_DEFAULT },
+	[IEEE80211_MODE_TURBO_A]= { .rssi = ROAM_RSSI_11A_DEFAULT,
+				    .rate = ROAM_RATE_11A_DEFAULT },
+	[IEEE80211_MODE_TURBO_G]= { .rssi = ROAM_RSSI_11A_DEFAULT,
+				    .rate = ROAM_RATE_11A_DEFAULT },
+	[IEEE80211_MODE_STURBO_A]={ .rssi = ROAM_RSSI_11A_DEFAULT,
+				    .rate = ROAM_RATE_11A_DEFAULT },
+	[IEEE80211_MODE_HALF]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
+				    .rate = ROAM_RATE_HALF_DEFAULT },
+	[IEEE80211_MODE_QUARTER]= { .rssi = ROAM_RSSI_11A_DEFAULT,
+				    .rate = ROAM_RATE_QUARTER_DEFAULT },
+	[IEEE80211_MODE_11NA]	= { .rssi = ROAM_RSSI_11A_DEFAULT,
+				    .rate = ROAM_MCS_11N_DEFAULT },
+	[IEEE80211_MODE_11NG]	= { .rssi = ROAM_RSSI_11B_DEFAULT,
+				    .rate = ROAM_MCS_11N_DEFAULT },
+};
+
+void
+ieee80211_scan_vattach(struct ieee80211vap *vap)
+{
+	vap->iv_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz;
+	vap->iv_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz;
+	vap->iv_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz;
+
+	vap->iv_roaming = IEEE80211_ROAMING_AUTO;
+	memcpy(vap->iv_roamparms, defroam, sizeof(defroam));
+}
+
+void
+ieee80211_scan_vdetach(struct ieee80211vap *vap)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss;
+
+	IEEE80211_LOCK(ic);
+	ss = ic->ic_scan;
+	if (ss != NULL && ss->ss_vap == vap) {
+		if (ic->ic_flags & IEEE80211_F_SCAN) {
+			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_ABORT;
+			scan_signal(ss);
+		}
+		if (ss->ss_ops != NULL) {
+			ss->ss_ops->scan_detach(ss);
+			ss->ss_ops = NULL;
+		}
+		ss->ss_vap = NULL;
+	}
+	IEEE80211_UNLOCK(ic);
+}
+
+/*
+ * Simple-minded scanner module support.
+ */
+static const char *scan_modnames[IEEE80211_OPMODE_MAX] = {
+	"wlan_scan_sta",	/* IEEE80211_M_IBSS */
+	"wlan_scan_sta",	/* IEEE80211_M_STA */
+	"wlan_scan_wds",	/* IEEE80211_M_WDS */
+	"wlan_scan_sta",	/* IEEE80211_M_AHDEMO */
+	"wlan_scan_ap",		/* IEEE80211_M_HOSTAP */
+	"wlan_scan_monitor",	/* IEEE80211_M_MONITOR */
+	"wlan_scan_sta",	/* IEEE80211_M_MBSS */
+};
+static const struct ieee80211_scanner *scanners[IEEE80211_OPMODE_MAX];
+
+const struct ieee80211_scanner *
+ieee80211_scanner_get(enum ieee80211_opmode mode)
+{
+	if (mode >= IEEE80211_OPMODE_MAX)
+		return NULL;
+	if (scanners[mode] == NULL)
+		ieee80211_load_module(scan_modnames[mode]);
+	return scanners[mode];
+}
+
+void
+ieee80211_scanner_register(enum ieee80211_opmode mode,
+	const struct ieee80211_scanner *scan)
+{
+	if (mode >= IEEE80211_OPMODE_MAX)
+		return;
+	scanners[mode] = scan;
+}
+
+void
+ieee80211_scanner_unregister(enum ieee80211_opmode mode,
+	const struct ieee80211_scanner *scan)
+{
+	if (mode >= IEEE80211_OPMODE_MAX)
+		return;
+	if (scanners[mode] == scan)
+		scanners[mode] = NULL;
+}
+
+void
+ieee80211_scanner_unregister_all(const struct ieee80211_scanner *scan)
+{
+	int m;
+
+	for (m = 0; m < IEEE80211_OPMODE_MAX; m++)
+		if (scanners[m] == scan)
+			scanners[m] = NULL;
+}
+
+/*
+ * Update common scanner state to reflect the current
+ * operating mode.  This is called when the state machine
+ * is transitioned to RUN state w/o scanning--e.g. when
+ * operating in monitor mode.  The purpose of this is to
+ * ensure later callbacks find ss_ops set to properly
+ * reflect current operating mode.
+ */
+static void
+scan_update_locked(struct ieee80211vap *vap,
+	const struct ieee80211_scanner *scan)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+
+	IEEE80211_LOCK_ASSERT(ic);
+
+#ifdef IEEE80211_DEBUG
+	if (ss->ss_vap != vap || ss->ss_ops != scan) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: current scanner is <%s:%s>, switch to <%s:%s>\n",
+		    __func__,
+		    ss->ss_vap != NULL ?
+			ss->ss_vap->iv_ifp->if_xname : "none",
+		    ss->ss_vap != NULL ?
+			ieee80211_opmode_name[ss->ss_vap->iv_opmode] : "none",
+		    vap->iv_ifp->if_xname,
+		    ieee80211_opmode_name[vap->iv_opmode]);
+	}
+#endif
+	ss->ss_vap = vap;
+	if (ss->ss_ops != scan) {
+		/*
+		 * Switch scanners; detach old, attach new.  Special
+		 * case where a single scan module implements multiple
+		 * policies by using different scan ops but a common
+		 * core.  We assume if the old and new attach methods
+		 * are identical then it's ok to just change ss_ops
+		 * and not flush the internal state of the module.
+		 */
+		if (scan == NULL || ss->ss_ops == NULL ||
+		    ss->ss_ops->scan_attach != scan->scan_attach) {
+			if (ss->ss_ops != NULL)
+				ss->ss_ops->scan_detach(ss);
+			if (scan != NULL && !scan->scan_attach(ss)) {
+				/* XXX attach failure */
+				/* XXX stat+msg */
+				scan = NULL;
+			}
+		}
+		ss->ss_ops = scan;
+	}
+}
+
+static char
+channel_type(const struct ieee80211_channel *c)
+{
+	if (IEEE80211_IS_CHAN_ST(c))
+		return 'S';
+	if (IEEE80211_IS_CHAN_108A(c))
+		return 'T';
+	if (IEEE80211_IS_CHAN_108G(c))
+		return 'G';
+	if (IEEE80211_IS_CHAN_HT(c))
+		return 'n';
+	if (IEEE80211_IS_CHAN_A(c))
+		return 'a';
+	if (IEEE80211_IS_CHAN_ANYG(c))
+		return 'g';
+	if (IEEE80211_IS_CHAN_B(c))
+		return 'b';
+	return 'f';
+}
+
+void
+ieee80211_scan_dump_channels(const struct ieee80211_scan_state *ss)
+{
+	struct ieee80211com *ic = ss->ss_ic;
+	const char *sep;
+	int i;
+
+	sep = "";
+	for (i = ss->ss_next; i < ss->ss_last; i++) {
+		const struct ieee80211_channel *c = ss->ss_chans[i];
+
+		printf("%s%u%c", sep, ieee80211_chan2ieee(ic, c),
+			channel_type(c));
+		sep = ", ";
+	}
+}
+
+#ifdef IEEE80211_DEBUG
+static void
+scan_dump(struct ieee80211_scan_state *ss)
+{
+	struct ieee80211vap *vap = ss->ss_vap;
+
+	if_printf(vap->iv_ifp, "scan set ");
+	ieee80211_scan_dump_channels(ss);
+	printf(" dwell min %lums max %lums\n",
+	    ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(ss->ss_maxdwell));
+}
+#endif /* IEEE80211_DEBUG */
+
+static void
+copy_ssid(struct ieee80211vap *vap, struct ieee80211_scan_state *ss,
+	int nssid, const struct ieee80211_scan_ssid ssids[])
+{
+	if (nssid > IEEE80211_SCAN_MAX_SSID) {
+		/* XXX printf */
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: too many ssid %d, ignoring all of them\n",
+		    __func__, nssid);
+		return;
+	}
+	memcpy(ss->ss_ssid, ssids, nssid * sizeof(ssids[0]));
+	ss->ss_nssid = nssid;
+}
+
+/*
+ * Start a scan unless one is already going.
+ */
+static int
+start_scan_locked(const struct ieee80211_scanner *scan,
+	struct ieee80211vap *vap, int flags, u_int duration,
+	u_int mindwell, u_int maxdwell,
+	u_int nssid, const struct ieee80211_scan_ssid ssids[])
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+
+	IEEE80211_LOCK_ASSERT(ic);
+
+	if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: scan inhibited by pending channel change\n", __func__);
+	} else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
+		    , __func__
+		    , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
+		    , duration, mindwell, maxdwell
+		    , ieee80211_phymode_name[vap->iv_des_mode]
+		    , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
+		    , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
+		    , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
+		    , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
+		    , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
+		    , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
+		);
+
+		scan_update_locked(vap, scan);
+		if (ss->ss_ops != NULL) {
+			if ((flags & IEEE80211_SCAN_NOSSID) == 0)
+				copy_ssid(vap, ss, nssid, ssids);
+
+			/* NB: top 4 bits for internal use */
+			ss->ss_flags = flags & 0xfff;
+			if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
+				vap->iv_stats.is_scan_active++;
+			else
+				vap->iv_stats.is_scan_passive++;
+			if (flags & IEEE80211_SCAN_FLUSH)
+				ss->ss_ops->scan_flush(ss);
+
+			/* NB: flush frames rx'd before 1st channel change */
+			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
+			SCAN_PRIVATE(ss)->ss_duration = duration;
+			ss->ss_next = 0;
+			ss->ss_mindwell = mindwell;
+			ss->ss_maxdwell = maxdwell;
+			/* NB: scan_start must be before the scan runtask */
+			ss->ss_ops->scan_start(ss, vap);
+#ifdef IEEE80211_DEBUG
+			if (ieee80211_msg_scan(vap))
+				scan_dump(ss);
+#endif /* IEEE80211_DEBUG */
+			ic->ic_flags |= IEEE80211_F_SCAN;
+			ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
+		}
+	} else {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: %s scan already in progress\n", __func__,
+		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
+	}
+	return (ic->ic_flags & IEEE80211_F_SCAN);
+}
+
+/*
+ * Start a scan unless one is already going.
+ */
+int
+ieee80211_start_scan(struct ieee80211vap *vap, int flags,
+	u_int duration, u_int mindwell, u_int maxdwell,
+	u_int nssid, const struct ieee80211_scan_ssid ssids[])
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	const struct ieee80211_scanner *scan;
+	int result;
+
+	scan = ieee80211_scanner_get(vap->iv_opmode);
+	if (scan == NULL) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: no scanner support for %s mode\n",
+		    __func__, ieee80211_opmode_name[vap->iv_opmode]);
+		/* XXX stat */
+		return 0;
+	}
+
+	IEEE80211_LOCK(ic);
+	result = start_scan_locked(scan, vap, flags, duration,
+	    mindwell, maxdwell, nssid, ssids);
+	IEEE80211_UNLOCK(ic);
+
+	return result;
+}
+
+/*
+ * Check the scan cache for an ap/channel to use; if that
+ * fails then kick off a new scan.
+ */
+int
+ieee80211_check_scan(struct ieee80211vap *vap, int flags,
+	u_int duration, u_int mindwell, u_int maxdwell,
+	u_int nssid, const struct ieee80211_scan_ssid ssids[])
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+	const struct ieee80211_scanner *scan;
+	int result;
+
+	scan = ieee80211_scanner_get(vap->iv_opmode);
+	if (scan == NULL) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: no scanner support for %s mode\n",
+		    __func__, vap->iv_opmode);
+		/* XXX stat */
+		return 0;
+	}
+
+	/*
+	 * Check if there's a list of scan candidates already.
+	 * XXX want more than the ap we're currently associated with
+	 */
+
+	IEEE80211_LOCK(ic);
+	IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+	    "%s: %s scan, %s%s%s%s%s\n"
+	    , __func__
+	    , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
+	    , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
+	    , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
+	    , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
+	    , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
+	    , flags & IEEE80211_SCAN_ONCE ? ", once" : ""
+	);
+
+	if (ss->ss_ops != scan) {
+		/* XXX re-use cache contents? e.g. adhoc<->sta */
+		flags |= IEEE80211_SCAN_FLUSH;
+	}
+	scan_update_locked(vap, scan);
+	if (ss->ss_ops != NULL) {
+		/* XXX verify ss_ops matches vap->iv_opmode */
+		if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
+			/*
+			 * Update the ssid list and mark flags so if
+			 * we call start_scan it doesn't duplicate work.
+			 */
+			copy_ssid(vap, ss, nssid, ssids);
+			flags |= IEEE80211_SCAN_NOSSID;
+		}
+		if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
+		    (flags & IEEE80211_SCAN_FLUSH) == 0 &&
+		    time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
+			/*
+			 * We're not currently scanning and the cache is
+			 * deemed hot enough to consult.  Lock out others
+			 * by marking IEEE80211_F_SCAN while we decide if
+			 * something is already in the scan cache we can
+			 * use.  Also discard any frames that might come
+			 * in while temporarily marked as scanning.
+			 */
+			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
+			ic->ic_flags |= IEEE80211_F_SCAN;
+
+			/* NB: need to use supplied flags in check */
+			ss->ss_flags = flags & 0xff;
+			result = ss->ss_ops->scan_end(ss, vap);
+
+			ic->ic_flags &= ~IEEE80211_F_SCAN;
+			SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
+			if (result) {
+				ieee80211_notify_scan_done(vap);
+				IEEE80211_UNLOCK(ic);
+				return 1;
+			}
+		}
+	}
+	result = start_scan_locked(scan, vap, flags, duration,
+	    mindwell, maxdwell, nssid, ssids);
+	IEEE80211_UNLOCK(ic);
+
+	return result;
+}
+
+/*
+ * Check the scan cache for an ap/channel to use; if that fails
+ * then kick off a scan using the current settings.
+ */
+int
+ieee80211_check_scan_current(struct ieee80211vap *vap)
+{
+	return ieee80211_check_scan(vap,
+	    IEEE80211_SCAN_ACTIVE,
+	    IEEE80211_SCAN_FOREVER, 0, 0,
+	    vap->iv_des_nssid, vap->iv_des_ssid);
+}
+
+/*
+ * Restart a previous scan.  If the previous scan completed
+ * then we start again using the existing channel list.
+ */
+int
+ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+	const struct ieee80211_scanner *scan;
+
+	scan = ieee80211_scanner_get(vap->iv_opmode);
+	if (scan == NULL) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: no scanner support for %s mode\n",
+		    __func__, vap->iv_opmode);
+		/* XXX stat */
+		return 0;
+	}
+
+	IEEE80211_LOCK(ic);
+	if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
+		u_int duration;
+		/*
+		 * Go off-channel for a fixed interval that is large
+		 * enough to catch most ap's but short enough that
+		 * we can return on-channel before our listen interval
+		 * expires.
+		 */
+		duration = IEEE80211_SCAN_OFFCHANNEL;
+
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: %s scan, ticks %u duration %lu\n", __func__,
+		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
+		    ticks, duration);
+
+		scan_update_locked(vap, scan);
+		if (ss->ss_ops != NULL) {
+			ss->ss_vap = vap;
+			/*
+			 * A background scan does not select a new sta; it
+			 * just refreshes the scan cache.  Also, indicate
+			 * the scan logic should follow the beacon schedule:
+			 * we go off-channel and scan for a while, then
+			 * return to the bss channel to receive a beacon,
+			 * then go off-channel again.  All during this time
+			 * we notify the ap we're in power save mode.  When
+			 * the scan is complete we leave power save mode.
+			 * If any beacon indicates there are frames pending
+			 * for us then we drop out of power save mode
+			 * (and background scan) automatically by way of the
+			 * usual sta power save logic.
+			 */
+			ss->ss_flags |= IEEE80211_SCAN_NOPICK
+				     |  IEEE80211_SCAN_BGSCAN
+				     |  flags
+				     ;
+			/* if previous scan completed, restart */
+			if (ss->ss_next >= ss->ss_last) {
+				if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
+					vap->iv_stats.is_scan_active++;
+				else
+					vap->iv_stats.is_scan_passive++;
+				/*
+				 * NB: beware of the scan cache being flushed;
+				 *     if the channel list is empty use the
+				 *     scan_start method to populate it.
+				 */
+				ss->ss_next = 0;
+				if (ss->ss_last != 0)
+					ss->ss_ops->scan_restart(ss, vap);
+				else {
+					ss->ss_ops->scan_start(ss, vap);
+#ifdef IEEE80211_DEBUG
+					if (ieee80211_msg_scan(vap))
+						scan_dump(ss);
+#endif /* IEEE80211_DEBUG */
+				}
+			}
+			/* NB: flush frames rx'd before 1st channel change */
+			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
+			SCAN_PRIVATE(ss)->ss_duration = duration;
+			ss->ss_maxdwell = duration;
+			ic->ic_flags |= IEEE80211_F_SCAN;
+			ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
+			ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
+		} else {
+			/* XXX msg+stat */
+		}
+	} else {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: %s scan already in progress\n", __func__,
+		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
+	}
+	IEEE80211_UNLOCK(ic);
+
+	/* NB: racey, does it matter? */
+	return (ic->ic_flags & IEEE80211_F_SCAN);
+}
+
+/*
+ * Cancel any scan currently going on for the specified vap.
+ */
+void
+ieee80211_cancel_scan(struct ieee80211vap *vap)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+
+	IEEE80211_LOCK(ic);
+	if ((ic->ic_flags & IEEE80211_F_SCAN) &&
+	    ss->ss_vap == vap &&
+	    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: cancel %s scan\n", __func__,
+		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
+			"active" : "passive");
+
+		/* clear bg scan NOPICK and mark cancel request */
+		ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
+		SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
+		/* wake up the scan task */
+		scan_signal(ss);
+	}
+	IEEE80211_UNLOCK(ic);
+}
+
+/*
+ * Cancel any scan currently going on.
+ */
+void
+ieee80211_cancel_anyscan(struct ieee80211vap *vap)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+
+	IEEE80211_LOCK(ic);
+	if ((ic->ic_flags & IEEE80211_F_SCAN) &&
+	    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: cancel %s scan\n", __func__,
+		    ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
+			"active" : "passive");
+
+		/* clear bg scan NOPICK and mark cancel request */
+		ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
+		SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
+		/* wake up the scan task */
+		scan_signal(ss);
+	}
+	IEEE80211_UNLOCK(ic);
+}
+
+/*
+ * Public access to scan_next for drivers that manage
+ * scanning themselves (e.g. for firmware-based devices).
+ */
+void
+ieee80211_scan_next(struct ieee80211vap *vap)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+
+	/* wake up the scan task */
+	IEEE80211_LOCK(ic);
+	scan_signal(ss);
+	IEEE80211_UNLOCK(ic);
+}
+
+/*
+ * Public access to scan_next for drivers that are not able to scan single
+ * channels (e.g. for firmware-based devices).
+ */
+void
+ieee80211_scan_done(struct ieee80211vap *vap)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss;
+
+	IEEE80211_LOCK(ic);
+	ss = ic->ic_scan;
+	ss->ss_next = ss->ss_last; /* all channels are complete */
+	scan_signal(ss);
+	IEEE80211_UNLOCK(ic);
+}
+
+/*
+ * 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 ieee80211vap *vap, int force)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+	struct ifnet *ifp = vap->iv_ifp;
+	int i;
+
+	if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
+		ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
+		return;
+	}
+	/*
+	 * Send directed probe requests followed by any
+	 * broadcast probe request.
+	 * XXX remove dependence on ic/vap->iv_bss
+	 */
+	for (i = 0; i < ss->ss_nssid; i++)
+		ieee80211_send_probereq(vap->iv_bss,
+			vap->iv_myaddr, ifp->if_broadcastaddr,
+			ifp->if_broadcastaddr,
+			ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
+	if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
+		ieee80211_send_probereq(vap->iv_bss,
+			vap->iv_myaddr, ifp->if_broadcastaddr,
+			ifp->if_broadcastaddr,
+			"", 0);
+}
+
+/*
+ * Scan curchan.  If this is an active scan and the channel
+ * is not marked passive then send probe request frame(s).
+ * Arrange for the channel change after maxdwell ticks.
+ */
+static void
+scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
+{
+	struct ieee80211vap *vap  = ss->ss_vap;
+
+	IEEE80211_LOCK(vap->iv_ic);
+	if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
+		ieee80211_probe_curchan(vap, 0);
+	callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
+	    maxdwell, scan_signal, ss);
+	IEEE80211_UNLOCK(vap->iv_ic);
+}
+
+static void
+scan_signal(void *arg)
+{
+	struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
+
+	IEEE80211_LOCK_ASSERT(ss->ss_ic);
+
+	cv_signal(&SCAN_PRIVATE(ss)->ss_scan_cv);
+}
+
+/*
+ * Handle mindwell requirements completed; initiate a channel
+ * change to the next channel asap.
+ */
+static void
+scan_mindwell(struct ieee80211_scan_state *ss)
+{
+	struct ieee80211com *ic = ss->ss_ic;
+
+	IEEE80211_LOCK(ic);
+	scan_signal(ss);
+	IEEE80211_UNLOCK(ic);
+}
+
+static void
+scan_task(void *arg, int pending)
+{
+#define	ISCAN_REP	(ISCAN_MINDWELL | ISCAN_DISCARD)
+	struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
+	struct ieee80211vap *vap = ss->ss_vap;
+	struct ieee80211com *ic = ss->ss_ic;
+	struct ieee80211_channel *chan;
+	unsigned long maxdwell, scanend;
+	int scandone = 0;
+
+	IEEE80211_LOCK(ic);
+	if (vap == NULL || (ic->ic_flags & IEEE80211_F_SCAN) == 0 ||
+	    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)) {
+		/* Cancelled before we started */
+		goto done;
+	}
+
+	if (ss->ss_next == ss->ss_last) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+			"%s: no channels to scan\n", __func__);
+		goto done;
+	}
+
+	if (vap->iv_opmode == IEEE80211_M_STA &&
+	    vap->iv_state == IEEE80211_S_RUN) {
+		if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
+			/* Enable station power save mode */
+			ieee80211_sta_pwrsave(vap, 1);
+			/*
+			 * Use an 1ms delay so the null data frame has a chance
+			 * to go out.
+			 * XXX Should use M_TXCB mechanism to eliminate this.
+			 */
+			cv_timedwait(&SCAN_PRIVATE(ss)->ss_scan_cv,
+			    IEEE80211_LOCK_OBJ(ic), hz / 1000);
+			if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
+				goto done;
+		}
+	}
+
+	scanend = ticks + SCAN_PRIVATE(ss)->ss_duration;
+	IEEE80211_UNLOCK(ic);
+	ic->ic_scan_start(ic);		/* notify driver */
+	IEEE80211_LOCK(ic);
+
+	for (;;) {
+		scandone = (ss->ss_next >= ss->ss_last) ||
+		    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0;
+		if (scandone || (ss->ss_flags & IEEE80211_SCAN_GOTPICK) ||
+		    (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT) ||
+		     time_after(ticks + ss->ss_mindwell, scanend))
+			break;
+
+		chan = ss->ss_chans[ss->ss_next++];
+
+		/*
+		 * Watch for truncation due to the scan end time.
+		 */
+		if (time_after(ticks + ss->ss_maxdwell, scanend))
+			maxdwell = scanend - ticks;
+		else
+			maxdwell = ss->ss_maxdwell;
+
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: chan %3d%c -> %3d%c [%s, dwell min %lums max %lums]\n",
+		    __func__,
+		    ieee80211_chan2ieee(ic, ic->ic_curchan),
+		        channel_type(ic->ic_curchan),
+		    ieee80211_chan2ieee(ic, chan), channel_type(chan),
+		    (ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
+			(chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
+			"active" : "passive",
+		    ticks_to_msecs(ss->ss_mindwell), ticks_to_msecs(maxdwell));
+
+		/*
+		 * Potentially change channel and phy mode.
+		 */
+		ic->ic_curchan = chan;
+		ic->ic_rt = ieee80211_get_ratetable(chan);
+		IEEE80211_UNLOCK(ic);
+		/*
+		 * Perform the channel change and scan unlocked so the driver
+		 * may sleep. Once set_channel returns the hardware has
+		 * completed the channel change.
+		 */
+		ic->ic_set_channel(ic);
+		ieee80211_radiotap_chan_change(ic);
+
+		/*
+		 * Scan curchan.  Drivers for "intelligent hardware"
+		 * override ic_scan_curchan to tell the device to do
+		 * the work.  Otherwise we manage the work outselves;
+		 * sending a probe request (as needed), and arming the
+		 * timeout to switch channels after maxdwell ticks.
+		 *
+		 * scan_curchan should only pause for the time required to
+		 * prepare/initiate the hardware for the scan (if at all), the
+		 * below condvar is used to sleep for the channels dwell time
+		 * and allows it to be signalled for abort.
+		 */
+		ic->ic_scan_curchan(ss, maxdwell);
+		IEEE80211_LOCK(ic);
+
+		SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell;
+		/* clear mindwell lock and initial channel change flush */
+		SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
+
+		if ((SCAN_PRIVATE(ss)->ss_iflags & (ISCAN_CANCEL|ISCAN_ABORT)))
+			continue;
+
+		/* Wait to be signalled to scan the next channel */
+		cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv, IEEE80211_LOCK_OBJ(ic));
+	}
+	if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
+		goto done;
+
+	IEEE80211_UNLOCK(ic);
+	ic->ic_scan_end(ic);		/* notify driver */
+	IEEE80211_LOCK(ic);
+
+	/*
+	 * Record scan complete time.  Note that we also do
+	 * this when canceled so any background scan will
+	 * not be restarted for a while.
+	 */
+	if (scandone)
+		ic->ic_lastscan = ticks;
+	/* return to the bss channel */
+	if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
+	    ic->ic_curchan != ic->ic_bsschan) {
+		ieee80211_setupcurchan(ic, ic->ic_bsschan);
+		IEEE80211_UNLOCK(ic);
+		ic->ic_set_channel(ic);
+		ieee80211_radiotap_chan_change(ic);
+		IEEE80211_LOCK(ic);
+	}
+	/* clear internal flags and any indication of a pick */
+	SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
+	ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
+
+	/*
+	 * If not canceled and scan completed, do post-processing.
+	 * If the callback function returns 0, then it wants to
+	 * continue/restart scanning.  Unfortunately we needed to
+	 * notify the driver to end the scan above to avoid having
+	 * rx frames alter the scan candidate list.
+	 */
+	if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 &&
+	    !ss->ss_ops->scan_end(ss, vap) &&
+	    (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
+	    time_before(ticks + ss->ss_mindwell, scanend)) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+		    "%s: done, restart "
+		    "[ticks %u, dwell min %lu scanend %lu]\n",
+		    __func__,
+		    ticks, ss->ss_mindwell, scanend);
+		ss->ss_next = 0;	/* reset to begining */
+		if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
+			vap->iv_stats.is_scan_active++;
+		else
+			vap->iv_stats.is_scan_passive++;
+
+		ss->ss_ops->scan_restart(ss, vap);	/* XXX? */
+		ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
+		IEEE80211_UNLOCK(ic);
+		return;
+	}
+
+	/* past here, scandone is ``true'' if not in bg mode */
+	if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
+		scandone = 1;
+
+	IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+	    "%s: %s, [ticks %u, dwell min %lu scanend %lu]\n",
+	    __func__, scandone ? "done" : "stopped",
+	    ticks, ss->ss_mindwell, scanend);
+
+	/*
+	 * Clear the SCAN bit first in case frames are
+	 * pending on the station power save queue.  If
+	 * we defer this then the dispatch of the frames
+	 * may generate a request to cancel scanning.
+	 */
+done:
+	ic->ic_flags &= ~IEEE80211_F_SCAN;
+	/*
+	 * Drop out of power save mode when a scan has
+	 * completed.  If this scan was prematurely terminated
+	 * because it is a background scan then don't notify
+	 * the ap; we'll either return to scanning after we
+	 * receive the beacon frame or we'll drop out of power
+	 * save mode because the beacon indicates we have frames
+	 * waiting for us.
+	 */
+	if (scandone) {
+		ieee80211_sta_pwrsave(vap, 0);
+		if (ss->ss_next >= ss->ss_last) {
+			ieee80211_notify_scan_done(vap);
+			ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
+		}
+	}
+	SCAN_PRIVATE(ss)->ss_iflags &= ~(ISCAN_CANCEL|ISCAN_ABORT);
+	ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
+	IEEE80211_UNLOCK(ic);
+#undef ISCAN_REP
+}
+
+#ifdef IEEE80211_DEBUG
+static void
+dump_country(const uint8_t *ie)
+{
+	const struct ieee80211_country_ie *cie =
+	   (const struct ieee80211_country_ie *) ie;
+	int i, nbands, schan, nchan;
+
+	if (cie->len < 3) {
+		printf(" <bogus country ie, len %d>", cie->len);
+		return;
+	}
+	printf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]);
+	nbands = (cie->len - 3) / sizeof(cie->band[0]);
+	for (i = 0; i < nbands; i++) {
+		schan = cie->band[i].schan;
+		nchan = cie->band[i].nchan;
+		if (nchan != 1)
+			printf(" %u-%u,%u", schan, schan + nchan-1,
+			    cie->band[i].maxtxpwr);
+		else
+			printf(" %u,%u", schan, cie->band[i].maxtxpwr);
+	}
+	printf("]");
+}
+
+static void
+dump_probe_beacon(uint8_t subtype, int isnew,
+	const uint8_t mac[IEEE80211_ADDR_LEN],
+	const struct ieee80211_scanparams *sp, int rssi)
+{
+
+	printf("[%s] %s%s on chan %u (bss chan %u) ",
+	    ether_sprintf(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(" rssi %d\n", rssi);
+
+	if (isnew) {
+		printf("[%s] caps 0x%x bintval %u erp 0x%x", 
+			ether_sprintf(mac), sp->capinfo, sp->bintval, sp->erp);
+		if (sp->country != NULL)
+			dump_country(sp->country);
+		printf("\n");
+	}
+}
+#endif /* IEEE80211_DEBUG */
+
+/*
+ * Process a beacon or probe response frame.
+ */
+void
+ieee80211_add_scan(struct ieee80211vap *vap,
+	const struct ieee80211_scanparams *sp,
+	const struct ieee80211_frame *wh,
+	int subtype, int rssi, int noise)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+
+	/* XXX locking */
+	/*
+	 * Frames received during startup are discarded to avoid
+	 * using scan state setup on the initial entry to the timer
+	 * callback.  This can occur because the device may enable
+	 * rx prior to our doing the initial channel change in the
+	 * timer routine.
+	 */
+	if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
+		return;
+#ifdef IEEE80211_DEBUG
+	if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
+		dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
+#endif
+	if (ss->ss_ops != NULL &&
+	    ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise)) {
+		/*
+		 * If we've reached the min dwell time terminate
+		 * the timer so we'll switch to the next channel.
+		 */
+		if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
+		    time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
+			IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
+			    "%s: chan %3d%c min dwell met (%u > %lu)\n",
+			    __func__,
+			    ieee80211_chan2ieee(ic, ic->ic_curchan),
+				channel_type(ic->ic_curchan),
+			    ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
+			SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
+			/*
+			 * NB: trigger at next clock tick or wait for the
+			 * hardware.
+			 */
+			ic->ic_scan_mindwell(ss);
+		}
+	}
+}
+
+/*
+ * Timeout/age scan cache entries; called from sta timeout
+ * timer (XXX should be self-contained).
+ */
+void
+ieee80211_scan_timeout(struct ieee80211com *ic)
+{
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+
+	if (ss->ss_ops != NULL)
+		ss->ss_ops->scan_age(ss);
+}
+
+/*
+ * Mark a scan cache entry after a successful associate.
+ */
+void
+ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
+{
+	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
+
+	if (ss->ss_ops != NULL) {
+		IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN,
+			mac, "%s",  __func__);
+		ss->ss_ops->scan_assoc_success(ss, mac);
+	}
+}
+
+/*
+ * Demerit a scan cache entry after failing to associate.
+ */
+void
+ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
+	const uint8_t mac[], int reason)
+{
+	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
+
+	if (ss->ss_ops != NULL) {
+		IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac,
+			"%s: reason %u", __func__, reason);
+		ss->ss_ops->scan_assoc_fail(ss, mac, reason);
+	}
+}
+
+/*
+ * Iterate over the contents of the scan cache.
+ */
+void
+ieee80211_scan_iterate(struct ieee80211vap *vap,
+	ieee80211_scan_iter_func *f, void *arg)
+{
+	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
+
+	if (ss->ss_ops != NULL)
+		ss->ss_ops->scan_iterate(ss, f, arg);
+}
+
+/*
+ * Flush the contents of the scan cache.
+ */
+void
+ieee80211_scan_flush(struct ieee80211vap *vap)
+{
+	struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
+
+	if (ss->ss_ops != NULL && ss->ss_vap == vap) {
+		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n",  __func__);
+		ss->ss_ops->scan_flush(ss);
+	}
+}
+
+/*
+ * Check the scan cache for an ap/channel to use; if that
+ * fails then kick off a new scan.
+ */
+struct ieee80211_channel *
+ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
+{
+	struct ieee80211_scan_state *ss = ic->ic_scan;
+
+	IEEE80211_LOCK_ASSERT(ic);
+
+	if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
+		/* XXX printf? */
+		return NULL;
+	}
+	if (ss->ss_ops->scan_pickchan == NULL) {
+		IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
+		    "%s: scan module does not support picking a channel, "
+		    "opmode %s\n", __func__, ss->ss_vap->iv_opmode);
+		return NULL;
+	}
+	return ss->ss_ops->scan_pickchan(ss, flags);
+}