linux/net/mac80211/scan.c

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/*
* Scanning implementation
*
* Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
* Copyright 2004, Instant802 Networks, Inc.
* Copyright 2005, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007, Michael Wu <flamingice@sourmilk.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/* TODO: figure out how to avoid that the "current BSS" expires */
#include <linux/wireless.h>
#include <linux/if_arp.h>
#include <linux/rtnetlink.h>
#include <net/mac80211.h>
#include <net/iw_handler.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
#include "mesh.h"
#define IEEE80211_PROBE_DELAY (HZ / 33)
#define IEEE80211_CHANNEL_TIME (HZ / 33)
#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)
struct ieee80211_bss *
ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
u8 *ssid, u8 ssid_len)
{
return (void *)cfg80211_get_bss(local->hw.wiphy,
ieee80211_get_channel(local->hw.wiphy,
freq),
bssid, ssid, ssid_len,
0, 0);
}
static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
{
struct ieee80211_bss *bss = (void *)cbss;
kfree(bss_mesh_id(bss));
kfree(bss_mesh_cfg(bss));
}
void ieee80211_rx_bss_put(struct ieee80211_local *local,
struct ieee80211_bss *bss)
{
cfg80211_put_bss((struct cfg80211_bss *)bss);
}
struct ieee80211_bss *
ieee80211_bss_info_update(struct ieee80211_local *local,
struct ieee80211_rx_status *rx_status,
struct ieee80211_mgmt *mgmt,
size_t len,
struct ieee802_11_elems *elems,
struct ieee80211_channel *channel,
bool beacon)
{
struct ieee80211_bss *bss;
int clen;
s32 signal = 0;
if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
signal = rx_status->signal * 100;
else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
signal = (rx_status->signal * 100) / local->hw.max_signal;
bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel,
mgmt, len, signal, GFP_ATOMIC);
if (!bss)
return NULL;
bss->cbss.free_priv = ieee80211_rx_bss_free;
/* save the ERP value so that it is available at association time */
if (elems->erp_info && elems->erp_info_len >= 1) {
bss->erp_value = elems->erp_info[0];
bss->has_erp_value = 1;
}
if (elems->tim) {
struct ieee80211_tim_ie *tim_ie =
(struct ieee80211_tim_ie *)elems->tim;
bss->dtim_period = tim_ie->dtim_period;
}
/* set default value for buggy APs */
if (!elems->tim || bss->dtim_period == 0)
bss->dtim_period = 1;
bss->supp_rates_len = 0;
if (elems->supp_rates) {
clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
if (clen > elems->supp_rates_len)
clen = elems->supp_rates_len;
memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates,
clen);
bss->supp_rates_len += clen;
}
if (elems->ext_supp_rates) {
clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
if (clen > elems->ext_supp_rates_len)
clen = elems->ext_supp_rates_len;
memcpy(&bss->supp_rates[bss->supp_rates_len],
elems->ext_supp_rates, clen);
bss->supp_rates_len += clen;
}
bss->wmm_used = elems->wmm_param || elems->wmm_info;
if (!beacon)
bss->last_probe_resp = jiffies;
return bss;
}
void ieee80211_rx_bss_remove(struct ieee80211_sub_if_data *sdata, u8 *bssid,
int freq, u8 *ssid, u8 ssid_len)
{
struct ieee80211_bss *bss;
struct ieee80211_local *local = sdata->local;
bss = ieee80211_rx_bss_get(local, bssid, freq, ssid, ssid_len);
if (bss) {
cfg80211_unlink_bss(local->hw.wiphy, (void *)bss);
ieee80211_rx_bss_put(local, bss);
}
}
ieee80211_rx_result
ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
{
struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_mgmt *mgmt;
struct ieee80211_bss *bss;
u8 *elements;
struct ieee80211_channel *channel;
size_t baselen;
int freq;
__le16 fc;
bool presp, beacon = false;
struct ieee802_11_elems elems;
if (skb->len < 2)
return RX_DROP_UNUSABLE;
mgmt = (struct ieee80211_mgmt *) skb->data;
fc = mgmt->frame_control;
if (ieee80211_is_ctl(fc))
return RX_CONTINUE;
if (skb->len < 24)
return RX_DROP_MONITOR;
presp = ieee80211_is_probe_resp(fc);
if (presp) {
/* ignore ProbeResp to foreign address */
if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
return RX_DROP_MONITOR;
presp = true;
elements = mgmt->u.probe_resp.variable;
baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
} else {
beacon = ieee80211_is_beacon(fc);
baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
elements = mgmt->u.beacon.variable;
}
if (!presp && !beacon)
return RX_CONTINUE;
if (baselen > skb->len)
return RX_DROP_MONITOR;
ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
if (elems.ds_params && elems.ds_params_len == 1)
freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
else
freq = rx_status->freq;
channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
return RX_DROP_MONITOR;
bss = ieee80211_bss_info_update(sdata->local, rx_status,
mgmt, skb->len, &elems,
channel, beacon);
if (bss)
ieee80211_rx_bss_put(sdata->local, bss);
dev_kfree_skb(skb);
return RX_QUEUED;
}
/*
* inform AP that we will go to sleep so that it will buffer the frames
* while we scan
*/
static void ieee80211_scan_ps_enable(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_local *local = sdata->local;
bool ps = false;
/* FIXME: what to do when local->pspolling is true? */
del_timer_sync(&local->dynamic_ps_timer);
cancel_work_sync(&local->dynamic_ps_enable_work);
if (local->hw.conf.flags & IEEE80211_CONF_PS) {
ps = true;
local->hw.conf.flags &= ~IEEE80211_CONF_PS;
ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
}
if (!ps || !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
/*
* If power save was enabled, no need to send a nullfunc
* frame because AP knows that we are sleeping. But if the
* hardware is creating the nullfunc frame for power save
* status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
* enabled) and power save was enabled, the firmware just
* sent a null frame with power save disabled. So we need
* to send a new nullfunc frame to inform the AP that we
* are again sleeping.
*/
ieee80211_send_nullfunc(local, sdata, 1);
}
/* inform AP that we are awake again, unless power save is enabled */
static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_local *local = sdata->local;
if (!local->ps_sdata)
ieee80211_send_nullfunc(local, sdata, 0);
else {
/*
* In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
* will send a nullfunc frame with the powersave bit set
* even though the AP already knows that we are sleeping.
* This could be avoided by sending a null frame with power
* save bit disabled before enabling the power save, but
* this doesn't gain anything.
*
* When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
* to send a nullfunc frame because AP already knows that
* we are sleeping, let's just enable power save mode in
* hardware.
*/
local->hw.conf.flags |= IEEE80211_CONF_PS;
ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
}
}
static void ieee80211_restore_scan_ies(struct ieee80211_local *local)
{
kfree(local->scan_req->ie);
local->scan_req->ie = local->orig_ies;
local->scan_req->ie_len = local->orig_ies_len;
}
void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
bool was_hw_scan;
mutex_lock(&local->scan_mtx);
if (WARN_ON(!local->hw_scanning && !local->sw_scanning)) {
mutex_unlock(&local->scan_mtx);
return;
}
if (WARN_ON(!local->scan_req)) {
mutex_unlock(&local->scan_mtx);
return;
}
if (local->hw_scanning)
ieee80211_restore_scan_ies(local);
if (local->scan_req != &local->int_scan_req)
cfg80211_scan_done(local->scan_req, aborted);
local->scan_req = NULL;
was_hw_scan = local->hw_scanning;
local->hw_scanning = false;
local->sw_scanning = false;
mac80211: fix scan channel race When a software scan starts, it first sets sw_scanning, but leaves the scan_channel "unset" (it currently actually gets initialised to a default). Now, when something else tries to (re)configure the hardware in the window between these two events (after sw_scanning = true, but before scan_channel is set), the current code switches to the (unset!) scan_channel. This causes trouble, especially when switching bands and sending frames on the wrong channel. To work around this, leave scan_channel initialised to NULL and use it to determine whether or not a switch to a different channel should occur (and also use the same condition to check whether to adjust power for scan or not). Additionally, avoid reconfiguring the hardware completely when recalculating idle resulted in no changes, this was the problem that originally led us to discover the race condition in the first place, which was helpfully bisected by Pavel. This part of the patch should not be necessary with the other fixes, but not calling the ieee80211_hw_config function when we know it to be unnecessary is certainly a correct thing to do. Unfortunately, this patch cannot and does not fix the race condition completely, but due to the way the scan code is structured it makes the particular problem Pavel discovered (race while changing channel at the same time as transmitting frames) go away. To fix it completely, more work especially with locking configuration is needed. Bisected-by: Pavel Roskin <proski@gnu.org> Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-05-07 12:23:01 +00:00
local->scan_channel = NULL;
/* we only have to protect scan_req and hw/sw scan */
mutex_unlock(&local->scan_mtx);
ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
mac80211: tell driver when idle When we aren't doing anything in mac80211, we can turn off much of the hardware, depending on the driver/hw. Not doing anything, aka being idle, means: * no monitor interfaces * no AP/mesh/wds interfaces * any station interfaces are in DISABLED state * any IBSS interfaces aren't trying to be in a network * we aren't trying to scan By creating a new function that verifies these conditions and calling it at strategic points where the states of those conditions change, we can easily make mac80211 tell the driver when we are idle to save power. Additionally, this fixes a small quirk where a recalculated powersave state is passed to the driver even if the hardware is about to stopped completely. This patch intentionally doesn't touch radio_enabled because that is currently implemented to be a soft rfkill which is inappropriate here when we need to be able to wake up with low latency. One thing I'm not entirely sure about is this: phy0: device no longer idle - in use wlan0: direct probe to AP 00:11:24:91:07:4d try 1 wlan0 direct probe responded wlan0: authenticate with AP 00:11:24:91:07:4d wlan0: authenticated > phy0: device now idle > phy0: device no longer idle - in use wlan0: associate with AP 00:11:24:91:07:4d wlan0: RX AssocResp from 00:11:24:91:07:4d (capab=0x401 status=0 aid=1) wlan0: associated Is it appropriate to go into idle state for a short time when we have just authenticated, but not associated yet? This happens only with the userspace SME, because we cannot really know how long it will wait before asking us to associate. Would going idle after a short timeout be more appropriate? We may need to revisit this, depending on what happens. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-29 10:26:17 +00:00
if (was_hw_scan)
goto done;
netif_tx_lock_bh(local->mdev);
netif_addr_lock(local->mdev);
local->filter_flags &= ~FIF_BCN_PRBRESP_PROMISC;
drv_configure_filter(local, FIF_BCN_PRBRESP_PROMISC,
&local->filter_flags,
local->mdev->mc_count,
local->mdev->mc_list);
netif_addr_unlock(local->mdev);
netif_tx_unlock_bh(local->mdev);
drv_sw_scan_complete(local);
mutex_lock(&local->iflist_mtx);
list_for_each_entry(sdata, &local->interfaces, list) {
if (!netif_running(sdata->dev))
continue;
/* Tell AP we're back */
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
ieee80211_scan_ps_disable(sdata);
netif_tx_wake_all_queues(sdata->dev);
}
} else
netif_tx_wake_all_queues(sdata->dev);
/* re-enable beaconing */
if (sdata->vif.type == NL80211_IFTYPE_AP ||
sdata->vif.type == NL80211_IFTYPE_ADHOC ||
sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
ieee80211_bss_info_change_notify(
sdata, BSS_CHANGED_BEACON_ENABLED);
}
mutex_unlock(&local->iflist_mtx);
done:
mac80211: tell driver when idle When we aren't doing anything in mac80211, we can turn off much of the hardware, depending on the driver/hw. Not doing anything, aka being idle, means: * no monitor interfaces * no AP/mesh/wds interfaces * any station interfaces are in DISABLED state * any IBSS interfaces aren't trying to be in a network * we aren't trying to scan By creating a new function that verifies these conditions and calling it at strategic points where the states of those conditions change, we can easily make mac80211 tell the driver when we are idle to save power. Additionally, this fixes a small quirk where a recalculated powersave state is passed to the driver even if the hardware is about to stopped completely. This patch intentionally doesn't touch radio_enabled because that is currently implemented to be a soft rfkill which is inappropriate here when we need to be able to wake up with low latency. One thing I'm not entirely sure about is this: phy0: device no longer idle - in use wlan0: direct probe to AP 00:11:24:91:07:4d try 1 wlan0 direct probe responded wlan0: authenticate with AP 00:11:24:91:07:4d wlan0: authenticated > phy0: device now idle > phy0: device no longer idle - in use wlan0: associate with AP 00:11:24:91:07:4d wlan0: RX AssocResp from 00:11:24:91:07:4d (capab=0x401 status=0 aid=1) wlan0: associated Is it appropriate to go into idle state for a short time when we have just authenticated, but not associated yet? This happens only with the userspace SME, because we cannot really know how long it will wait before asking us to associate. Would going idle after a short timeout be more appropriate? We may need to revisit this, depending on what happens. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-29 10:26:17 +00:00
ieee80211_recalc_idle(local);
ieee80211_mlme_notify_scan_completed(local);
ieee80211_ibss_notify_scan_completed(local);
ieee80211_mesh_notify_scan_completed(local);
}
EXPORT_SYMBOL(ieee80211_scan_completed);
static int ieee80211_start_sw_scan(struct ieee80211_local *local)
{
struct ieee80211_sub_if_data *sdata;
/*
* Hardware/driver doesn't support hw_scan, so use software
* scanning instead. First send a nullfunc frame with power save
* bit on so that AP will buffer the frames for us while we are not
* listening, then send probe requests to each channel and wait for
* the responses. After all channels are scanned, tune back to the
* original channel and send a nullfunc frame with power save bit
* off to trigger the AP to send us all the buffered frames.
*
* Note that while local->sw_scanning is true everything else but
* nullfunc frames and probe requests will be dropped in
* ieee80211_tx_h_check_assoc().
*/
drv_sw_scan_start(local);
mutex_lock(&local->iflist_mtx);
list_for_each_entry(sdata, &local->interfaces, list) {
if (!netif_running(sdata->dev))
continue;
/* disable beaconing */
if (sdata->vif.type == NL80211_IFTYPE_AP ||
sdata->vif.type == NL80211_IFTYPE_ADHOC ||
sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
ieee80211_bss_info_change_notify(
sdata, BSS_CHANGED_BEACON_ENABLED);
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
netif_tx_stop_all_queues(sdata->dev);
ieee80211_scan_ps_enable(sdata);
}
} else
netif_tx_stop_all_queues(sdata->dev);
}
mutex_unlock(&local->iflist_mtx);
local->scan_state = SCAN_SET_CHANNEL;
local->scan_channel_idx = 0;
netif_addr_lock_bh(local->mdev);
local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
drv_configure_filter(local, FIF_BCN_PRBRESP_PROMISC,
&local->filter_flags,
local->mdev->mc_count,
local->mdev->mc_list);
netif_addr_unlock_bh(local->mdev);
/* TODO: start scan as soon as all nullfunc frames are ACKed */
queue_delayed_work(local->hw.workqueue, &local->scan_work,
IEEE80211_CHANNEL_TIME);
return 0;
}
static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
struct cfg80211_scan_request *req)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
int rc;
if (local->scan_req)
return -EBUSY;
if (local->ops->hw_scan) {
u8 *ies;
int ielen;
ies = kmalloc(2 + IEEE80211_MAX_SSID_LEN +
local->scan_ies_len + req->ie_len, GFP_KERNEL);
if (!ies)
return -ENOMEM;
ielen = ieee80211_build_preq_ies(local, ies,
req->ie, req->ie_len);
local->orig_ies = req->ie;
local->orig_ies_len = req->ie_len;
req->ie = ies;
req->ie_len = ielen;
}
local->scan_req = req;
local->scan_sdata = sdata;
if (req != &local->int_scan_req &&
sdata->vif.type == NL80211_IFTYPE_STATION &&
(ifmgd->state == IEEE80211_STA_MLME_DIRECT_PROBE ||
ifmgd->state == IEEE80211_STA_MLME_AUTHENTICATE ||
ifmgd->state == IEEE80211_STA_MLME_ASSOCIATE)) {
/* actually wait for the assoc to finish/time out */
set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
return 0;
}
if (local->ops->hw_scan)
local->hw_scanning = true;
else
local->sw_scanning = true;
/*
* Kicking off the scan need not be protected,
* only the scan variable stuff, since now
* local->scan_req is assigned and other callers
* will abort their scan attempts.
*
* This avoids getting a scan_mtx -> iflist_mtx
* dependency, so that the scan completed calls
* have more locking freedom.
*/
mac80211: tell driver when idle When we aren't doing anything in mac80211, we can turn off much of the hardware, depending on the driver/hw. Not doing anything, aka being idle, means: * no monitor interfaces * no AP/mesh/wds interfaces * any station interfaces are in DISABLED state * any IBSS interfaces aren't trying to be in a network * we aren't trying to scan By creating a new function that verifies these conditions and calling it at strategic points where the states of those conditions change, we can easily make mac80211 tell the driver when we are idle to save power. Additionally, this fixes a small quirk where a recalculated powersave state is passed to the driver even if the hardware is about to stopped completely. This patch intentionally doesn't touch radio_enabled because that is currently implemented to be a soft rfkill which is inappropriate here when we need to be able to wake up with low latency. One thing I'm not entirely sure about is this: phy0: device no longer idle - in use wlan0: direct probe to AP 00:11:24:91:07:4d try 1 wlan0 direct probe responded wlan0: authenticate with AP 00:11:24:91:07:4d wlan0: authenticated > phy0: device now idle > phy0: device no longer idle - in use wlan0: associate with AP 00:11:24:91:07:4d wlan0: RX AssocResp from 00:11:24:91:07:4d (capab=0x401 status=0 aid=1) wlan0: associated Is it appropriate to go into idle state for a short time when we have just authenticated, but not associated yet? This happens only with the userspace SME, because we cannot really know how long it will wait before asking us to associate. Would going idle after a short timeout be more appropriate? We may need to revisit this, depending on what happens. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-29 10:26:17 +00:00
ieee80211_recalc_idle(local);
mutex_unlock(&local->scan_mtx);
if (local->ops->hw_scan)
rc = drv_hw_scan(local, local->scan_req);
else
rc = ieee80211_start_sw_scan(local);
mutex_lock(&local->scan_mtx);
if (rc) {
if (local->ops->hw_scan) {
local->hw_scanning = false;
ieee80211_restore_scan_ies(local);
} else
local->sw_scanning = false;
mac80211: tell driver when idle When we aren't doing anything in mac80211, we can turn off much of the hardware, depending on the driver/hw. Not doing anything, aka being idle, means: * no monitor interfaces * no AP/mesh/wds interfaces * any station interfaces are in DISABLED state * any IBSS interfaces aren't trying to be in a network * we aren't trying to scan By creating a new function that verifies these conditions and calling it at strategic points where the states of those conditions change, we can easily make mac80211 tell the driver when we are idle to save power. Additionally, this fixes a small quirk where a recalculated powersave state is passed to the driver even if the hardware is about to stopped completely. This patch intentionally doesn't touch radio_enabled because that is currently implemented to be a soft rfkill which is inappropriate here when we need to be able to wake up with low latency. One thing I'm not entirely sure about is this: phy0: device no longer idle - in use wlan0: direct probe to AP 00:11:24:91:07:4d try 1 wlan0 direct probe responded wlan0: authenticate with AP 00:11:24:91:07:4d wlan0: authenticated > phy0: device now idle > phy0: device no longer idle - in use wlan0: associate with AP 00:11:24:91:07:4d wlan0: RX AssocResp from 00:11:24:91:07:4d (capab=0x401 status=0 aid=1) wlan0: associated Is it appropriate to go into idle state for a short time when we have just authenticated, but not associated yet? This happens only with the userspace SME, because we cannot really know how long it will wait before asking us to associate. Would going idle after a short timeout be more appropriate? We may need to revisit this, depending on what happens. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-29 10:26:17 +00:00
ieee80211_recalc_idle(local);
local->scan_req = NULL;
local->scan_sdata = NULL;
}
return rc;
}
void ieee80211_scan_work(struct work_struct *work)
{
struct ieee80211_local *local =
container_of(work, struct ieee80211_local, scan_work.work);
struct ieee80211_sub_if_data *sdata = local->scan_sdata;
struct ieee80211_channel *chan;
int skip, i;
unsigned long next_delay = 0;
mutex_lock(&local->scan_mtx);
if (!sdata || !local->scan_req) {
mutex_unlock(&local->scan_mtx);
return;
}
if (local->scan_req && !(local->sw_scanning || local->hw_scanning)) {
struct cfg80211_scan_request *req = local->scan_req;
int rc;
local->scan_req = NULL;
rc = __ieee80211_start_scan(sdata, req);
mutex_unlock(&local->scan_mtx);
if (rc)
ieee80211_scan_completed(&local->hw, true);
return;
}
mutex_unlock(&local->scan_mtx);
/*
* Avoid re-scheduling when the sdata is going away.
*/
if (!netif_running(sdata->dev)) {
ieee80211_scan_completed(&local->hw, true);
return;
}
switch (local->scan_state) {
case SCAN_SET_CHANNEL:
/* if no more bands/channels left, complete scan */
if (local->scan_channel_idx >= local->scan_req->n_channels) {
ieee80211_scan_completed(&local->hw, false);
return;
}
skip = 0;
chan = local->scan_req->channels[local->scan_channel_idx];
if (chan->flags & IEEE80211_CHAN_DISABLED ||
(sdata->vif.type == NL80211_IFTYPE_ADHOC &&
chan->flags & IEEE80211_CHAN_NO_IBSS))
skip = 1;
if (!skip) {
local->scan_channel = chan;
if (ieee80211_hw_config(local,
IEEE80211_CONF_CHANGE_CHANNEL))
skip = 1;
}
/* advance state machine to next channel/band */
local->scan_channel_idx++;
if (skip)
break;
/*
* Probe delay is used to update the NAV, cf. 11.1.3.2.2
* (which unfortunately doesn't say _why_ step a) is done,
* but it waits for the probe delay or until a frame is
* received - and the received frame would update the NAV).
* For now, we do not support waiting until a frame is
* received.
*
* In any case, it is not necessary for a passive scan.
*/
if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
!local->scan_req->n_ssids) {
next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
break;
}
next_delay = IEEE80211_PROBE_DELAY;
local->scan_state = SCAN_SEND_PROBE;
break;
case SCAN_SEND_PROBE:
for (i = 0; i < local->scan_req->n_ssids; i++)
ieee80211_send_probe_req(
sdata, NULL,
local->scan_req->ssids[i].ssid,
local->scan_req->ssids[i].ssid_len,
local->scan_req->ie, local->scan_req->ie_len);
/*
* After sending probe requests, wait for probe responses
* on the channel.
*/
next_delay = IEEE80211_CHANNEL_TIME;
local->scan_state = SCAN_SET_CHANNEL;
break;
}
queue_delayed_work(local->hw.workqueue, &local->scan_work,
next_delay);
}
int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
struct cfg80211_scan_request *req)
{
int res;
mutex_lock(&sdata->local->scan_mtx);
res = __ieee80211_start_scan(sdata, req);
mutex_unlock(&sdata->local->scan_mtx);
return res;
}
int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
const u8 *ssid, u8 ssid_len)
{
struct ieee80211_local *local = sdata->local;
int ret = -EBUSY;
mutex_lock(&local->scan_mtx);
/* busy scanning */
if (local->scan_req)
goto unlock;
memcpy(local->int_scan_req.ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
local->int_scan_req.ssids[0].ssid_len = ssid_len;
ret = __ieee80211_start_scan(sdata, &sdata->local->int_scan_req);
unlock:
mutex_unlock(&local->scan_mtx);
return ret;
}
void ieee80211_scan_cancel(struct ieee80211_local *local)
{
bool swscan;
cancel_delayed_work_sync(&local->scan_work);
/*
* Only call this function when a scan can't be
* queued -- mostly at suspend under RTNL.
*/
mutex_lock(&local->scan_mtx);
swscan = local->sw_scanning;
mutex_unlock(&local->scan_mtx);
if (swscan)
ieee80211_scan_completed(&local->hw, true);
}