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mac80211: implement basic background scanning

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Introduce a new scan flag "SCAN_OFF_CHANNEL" which basically tells us
that we are currently on a different channel for scanning and cannot
RX/TX. "SCAN_SW_SCANNING" tells us that we are currently running a
software scan but we might as well be on the operating channel to RX/TX.
While "SCAN_SW_SCANNING" is set during the whole scan "SCAN_OFF_CHANNEL"
is set when leaving the operating channel and unset when coming back.

Introduce two new scan states "SCAN_LEAVE_OPER_CHANNEL" and
"SCAN_ENTER_OPER_CHANNEL" which basically implement the functionality we
need to leave the operating channel (send a nullfunc to the AP and stop
the queues) and enter it again (send a nullfunc to the AP and start the
queues again).

Enhance the scan state "SCAN_DECISION" to switch back to the operating
channel after each scanned channel. In the future it sould be simple
to enhance the decision state to scan as much channels in a row as the
qos latency allows us.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Helmut Schaa
2009-07-23 13:18:01 +02:00
committed by John W. Linville
parent fbe9c429f1
commit 142b9f5074
4 changed files with 148 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

117
net/mac80211/scan.c
View File

@@ -365,12 +365,11 @@ static int ieee80211_start_sw_scan(struct ieee80211_local *local)
ieee80211_bss_info_change_notify(
sdata, BSS_CHANGED_BEACON_ENABLED);
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
if (sdata->u.mgd.associated) {
netif_tx_stop_all_queues(sdata->dev);
ieee80211_scan_ps_enable(sdata);
}
} else
/*
* only handle non-STA interfaces here, STA interfaces
* are handled in the scan state machine
*/
if (sdata->vif.type != NL80211_IFTYPE_STATION)
netif_tx_stop_all_queues(sdata->dev);
}
mutex_unlock(&local->iflist_mtx);
@@ -474,17 +473,113 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
static int ieee80211_scan_state_decision(struct ieee80211_local *local,
unsigned long *next_delay)
{
/* if no more bands/channels left, complete scan */
bool associated = false;
struct ieee80211_sub_if_data *sdata;
/* if no more bands/channels left, complete scan and advance to the idle state */
if (local->scan_channel_idx >= local->scan_req->n_channels) {
ieee80211_scan_completed(&local->hw, false);
return 1;
}
/* check if at least one STA interface is associated */
mutex_lock(&local->iflist_mtx);
list_for_each_entry(sdata, &local->interfaces, list) {
if (!netif_running(sdata->dev))
continue;
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
if (sdata->u.mgd.associated) {
associated = true;
break;
}
}
}
mutex_unlock(&local->iflist_mtx);
if (local->scan_channel) {
/*
* we're currently scanning a different channel, let's
* switch back to the operating channel now if at least
* one interface is associated. Otherwise just scan the
* next channel
*/
if (associated)
local->scan_state = SCAN_ENTER_OPER_CHANNEL;
else
local->scan_state = SCAN_SET_CHANNEL;
} else {
/*
* we're on the operating channel currently, let's
* leave that channel now to scan another one
*/
local->scan_state = SCAN_LEAVE_OPER_CHANNEL;
}
*next_delay = 0;
local->scan_state = SCAN_SET_CHANNEL;
return 0;
}
static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
unsigned long *next_delay)
{
struct ieee80211_sub_if_data *sdata;
/*
* notify the AP about us leaving the channel and stop all STA interfaces
*/
mutex_lock(&local->iflist_mtx);
list_for_each_entry(sdata, &local->interfaces, list) {
if (!netif_running(sdata->dev))
continue;
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
netif_tx_stop_all_queues(sdata->dev);
if (sdata->u.mgd.associated)
ieee80211_scan_ps_enable(sdata);
}
}
mutex_unlock(&local->iflist_mtx);
__set_bit(SCAN_OFF_CHANNEL, &local->scanning);
/* advance to the next channel to be scanned */
*next_delay = HZ / 10;
local->scan_state = SCAN_SET_CHANNEL;
}
static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
unsigned long *next_delay)
{
struct ieee80211_sub_if_data *sdata = local->scan_sdata;
/* switch back to the operating channel */
local->scan_channel = NULL;
ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
/*
* notify the AP about us being back and restart all STA interfaces
*/
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.associated)
ieee80211_scan_ps_disable(sdata);
netif_tx_wake_all_queues(sdata->dev);
}
}
mutex_unlock(&local->iflist_mtx);
__clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
*next_delay = HZ / 5;
local->scan_state = SCAN_DECISION;
}
static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
unsigned long *next_delay)
{
@@ -609,6 +704,12 @@ void ieee80211_scan_work(struct work_struct *work)
case SCAN_SEND_PROBE:
ieee80211_scan_state_send_probe(local, &next_delay);
break;
case SCAN_LEAVE_OPER_CHANNEL:
ieee80211_scan_state_leave_oper_channel(local, &next_delay);
break;
case SCAN_ENTER_OPER_CHANNEL:
ieee80211_scan_state_enter_oper_channel(local, &next_delay);
break;
}
} while (next_delay == 0);