Introduce a new scan flag "SCAN_BG_SCANNING" which basically tells us
that we are currently scanning but may as well be on the operating channel
to RX/TX data whereas "SCAN_SW_SCANNING" tells us that we are currently
on a different channel for scanning. While "SCAN_BG_SCANNING" is set
during the whole scan "SCAN_SW_SCANNING" 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@xxxxxxxxxxxxxx>
---
net/mac80211/ieee80211_i.h | 36 +++++++++++++-
net/mac80211/rx.c | 6 ++
net/mac80211/scan.c | 117 +++++++++++++++++++++++++++++++++++++++++---
net/mac80211/tx.c | 2 -
4 files changed, 148 insertions(+), 13 deletions(-)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 783a125..efda19e 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -570,9 +570,41 @@ enum queue_stop_reason {
IEEE80211_QUEUE_STOP_REASON_SKB_ADD,
};
+/**
+ * mac80211 scan flags - currently active scan mode
+ *
+ * @SCAN_SW_SCANNING: We're currently in the process of scanning but may as
+ * well be on the operating channel
+ * @SCAN_HW_SCANNING: The hardware is scanning for us, we have no way to
+ * determine if we are on the operating channel or not
+ * @SCAN_OFF_CHANNEL: We're off our operating channel for scanning,
+ * gets only set in conjunction with SCAN_SW_SCANNING
+ */
enum {
SCAN_SW_SCANNING,
- SCAN_HW_SCANNING
+ SCAN_HW_SCANNING,
+ SCAN_OFF_CHANNEL,
+};
+
+/**
+ * enum mac80211_scan_state - scan state machine states
+ *
+ * @SCAN_DECISION: Main entry point to the scan state machine, this state
+ * determines if we should keep on scanning or switch back to the
+ * operating channel
+ * @SCAN_SET_CHANNEL: Set the next channel to be scanned
+ * @SCAN_SEND_PROBE: Send probe requests and wait for probe responses
+ * @SCAN_LEAVE_OPER_CHANNEL: Leave the operating channel, notify the AP
+ * about us leaving the channel and stop all associated STA interfaces
+ * @SCAN_ENTER_OPER_CHANNEL: Enter the operating channel again, notify the
+ * AP about us being back and restart all associated STA interfaces
+ */
+enum mac80211_scan_state {
+ SCAN_DECISION,
+ SCAN_SET_CHANNEL,
+ SCAN_SEND_PROBE,
+ SCAN_LEAVE_OPER_CHANNEL,
+ SCAN_ENTER_OPER_CHANNEL,
};
struct ieee80211_local {
@@ -683,7 +715,7 @@ struct ieee80211_local {
int scan_channel_idx;
int scan_ies_len;
- enum { SCAN_DECISION, SCAN_SET_CHANNEL, SCAN_SEND_PROBE } scan_state;
+ enum mac80211_scan_state scan_state;
struct delayed_work scan_work;
struct ieee80211_sub_if_data *scan_sdata;
enum nl80211_channel_type oper_channel_type;
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index b1bebc1..dd192b3 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -421,7 +421,8 @@ ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning)))
return ieee80211_scan_rx(rx->sdata, skb);
- if (unlikely(test_bit(SCAN_SW_SCANNING, &local->scanning))) {
+ if (unlikely(test_bit(SCAN_SW_SCANNING, &local->scanning) &&
+ (rx->flags & IEEE80211_RX_IN_SCAN))) {
/* drop all the other packets during a software scan anyway */
if (ieee80211_scan_rx(rx->sdata, skb) != RX_QUEUED)
dev_kfree_skb(skb);
@@ -2136,7 +2137,8 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
return;
}
- if (unlikely(local->scanning))
+ if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning) ||
+ test_bit(SCAN_OFF_CHANNEL, &local->scanning)))
rx.flags |= IEEE80211_RX_IN_SCAN;
ieee80211_parse_qos(&rx);
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 4233c3d..d56b9da 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -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);
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 61739ab..275bc15 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -192,7 +192,7 @@ ieee80211_tx_h_check_assoc(struct ieee80211_tx_data *tx)
if (unlikely(info->flags & IEEE80211_TX_CTL_INJECTED))
return TX_CONTINUE;
- if (unlikely(test_bit(SCAN_SW_SCANNING, &tx->local->scanning)) &&
+ if (unlikely(test_bit(SCAN_OFF_CHANNEL, &tx->local->scanning)) &&
!ieee80211_is_probe_req(hdr->frame_control) &&
!ieee80211_is_nullfunc(hdr->frame_control))
/*
--
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