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freebsd-dev/sys/net80211/ieee80211_scan_sw.c

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/*-
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* IEEE 802.11 scanning support.
*/
#include "opt_wlan.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/condvar.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_media.h>
#include <net/ethernet.h>
#include <net80211/ieee80211_var.h>
#include <net80211/ieee80211_scan_sw.h>
#include <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_swscan_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;
/*
* TODO: all of the non-vap scan calls should be methods!
*/
}
void
ieee80211_swscan_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"));
/*
* For now, do the ss_ops detach here rather
* than ieee80211_scan_detach().
*
* I'll figure out how to cleanly split things up
* at a later date.
*/
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);
}
}
void
ieee80211_swscan_vattach(struct ieee80211vap *vap)
{
/* nothing to do for now */
/*
* TODO: all of the vap scan calls should be methods!
*/
}
void
ieee80211_swscan_vdetach(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss;
IEEE80211_LOCK_ASSERT(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);
}
}
}
void
ieee80211_swscan_set_scan_duration(struct ieee80211vap *vap, u_int duration)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
IEEE80211_LOCK_ASSERT(ic);
/* NB: flush frames rx'd before 1st channel change */
SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
SCAN_PRIVATE(ss)->ss_duration = duration;
}
void
ieee80211_swscan_run_scan_task(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
IEEE80211_LOCK_ASSERT(ic);
ieee80211_runtask(ic, &SCAN_PRIVATE(ss)->ss_scan_task);
}
/*
* Start a scan unless one is already going.
*
* Called without the comlock held; grab the comlock as appropriate.
*/
int
ieee80211_swscan_start_scan(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;
int result;
IEEE80211_UNLOCK_ASSERT(ic);
IEEE80211_LOCK(ic);
result = ieee80211_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.
*
* Called with the comlock held.
*
* XXX TODO: split out!
*/
int
ieee80211_swscan_check_scan(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;
int result;
IEEE80211_LOCK_ASSERT(ic);
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.
*/
ieee80211_scan_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);
return 1;
}
}
}
result = ieee80211_start_scan_locked(scan, vap, flags, duration,
mindwell, maxdwell, nssid, ssids);
return result;
}
/*
* Restart a previous scan. If the previous scan completed
* then we start again using the existing channel list.
*/
int
ieee80211_swscan_bg_scan(const struct ieee80211_scanner *scan,
struct ieee80211vap *vap, int flags)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
/* XXX assert unlocked? */
// IEEE80211_UNLOCK_ASSERT(ic);
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);
ieee80211_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))
ieee80211_scan_dump(ss);
#endif /* IEEE80211_DEBUG */
}
}
ieee80211_swscan_set_scan_duration(vap, 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_swscan_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);
} else {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: called; F_SCAN=%d, vap=%s, CANCEL=%d\n",
__func__,
!! (ic->ic_flags & IEEE80211_F_SCAN),
(ss->ss_vap == vap ? "match" : "nomatch"),
!! (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL));
}
IEEE80211_UNLOCK(ic);
}
/*
* Cancel any scan currently going on.
*/
void
ieee80211_swscan_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);
} else {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: called; F_SCAN=%d, vap=%s, CANCEL=%d\n",
__func__,
!! (ic->ic_flags & IEEE80211_F_SCAN),
(ss->ss_vap == vap ? "match" : "nomatch"),
!! (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL));
}
IEEE80211_UNLOCK(ic);
}
/*
* Public access to scan_next for drivers that manage
* scanning themselves (e.g. for firmware-based devices).
*/
void
ieee80211_swscan_scan_next(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
/* 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_swscan_scan_done(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss;
IEEE80211_LOCK_ASSERT(ic);
ss = ic->ic_scan;
scan_signal(ss);
}
/*
* 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_swscan_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;
/*
* 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_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: calling; maxdwell=%lu\n",
__func__,
maxdwell);
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_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: called\n", __func__);
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__);
scandone = 1;
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 */
vap->iv_sta_ps(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;
/* XXX scan state can change! Re-validate scan state! */
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;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: loop start; scandone=%d\n",
__func__,
scandone);
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),
ieee80211_channel_type_char(ic->ic_curchan),
ieee80211_chan2ieee(ic, chan),
ieee80211_channel_type_char(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);
/* XXX scan state can change! Re-validate scan state! */
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;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: waiting\n", __func__);
/* Wait to be signalled to scan the next channel */
cv_wait(&SCAN_PRIVATE(ss)->ss_scan_cv, IEEE80211_LOCK_OBJ(ic));
}
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: out\n", __func__);
if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_ABORT)
goto done;
IEEE80211_UNLOCK(ic);
ic->ic_scan_end(ic); /* notify driver */
IEEE80211_LOCK(ic);
/* XXX scan state can change! Re-validate scan state! */
/*
* Since a cancellation may have occured during one of the
* driver calls (whilst unlocked), update scandone.
*/
if (scandone == 0 &&
((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0)) {
/* XXX printf? */
if_printf(vap->iv_ifp,
"%s: OOPS! scan cancelled during driver call (1)!\n",
__func__);
scandone = 1;
}
/*
* 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);
/*
* Since a cancellation may have occured during one of the
* driver calls (whilst unlocked), update scandone.
*/
if (scandone == 0 &&
((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0)) {
/* XXX printf? */
if_printf(vap->iv_ifp,
"%s: OOPS! scan cancelled during driver call (2)!\n",
__func__);
scandone = 1;
}
/*
* 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) {
vap->iv_sta_ps(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
}
/*
* Process a beacon or probe response frame.
*/
void
ieee80211_swscan_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))
ieee80211_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),
ieee80211_channel_type_char(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);
}
}
}
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