On Wednesday 28 February 2007 16:42, Michael Wu wrote:
> This makes scans switch STA interfaces into PS mode so the AP queues frames
> destined for us while we are scanning. This is achieved by sending a
> nullfunc data frame with the PS mode bit set before scanning commences,
> and a PS poll frame after scanning is completed.
>
Er. I should update the description too..
--
d80211: switch STA interfaces to PS mode during scan
From: Michael Wu <flamingice@xxxxxxxxxxxx>
This makes scans switch STA interfaces into PS mode so the AP queues frames
destined for us while we are scanning. This is achieved by sending a
nullfunc data frame with the PS mode bit set before scanning commences,
and a nullfunc data frame without the PS mode bit set after scanning is
completed.
Signed-off-by: Michael Wu <flamingice@xxxxxxxxxxxx>
---
include/linux/ieee80211.h | 7 ++++++
net/mac80211/ieee80211_sta.c | 51
+++++++++++++++++++++++++++++++++++-------
2 files changed, 50 insertions(+), 8 deletions(-)
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 4379b1d..836bde2 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -203,6 +203,13 @@ struct ieee80211_cts {
__u8 ra[6];
} __attribute__ ((packed));
+struct ieee80211_ps_poll {
+ __le16 frame_control;
+ __le16 aid;
+ __u8 bssid[6];
+ __u8 ta[6];
+} __attribute__ ((packed));
+
/* Authentication algorithms */
#define WLAN_AUTH_OPEN 0
diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c
index 280b24f..747662d 100644
--- a/net/mac80211/ieee80211_sta.c
+++ b/net/mac80211/ieee80211_sta.c
@@ -2523,6 +2523,37 @@ int ieee80211_sta_set_bssid(struct net_d
}
+static void ieee80211_send_nullfunc(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata,
+ int powersave)
+{
+ struct sk_buff *skb;
+ struct ieee80211_hdr *nullfunc;
+ u16 fc;
+
+ skb = dev_alloc_skb(local->hw.extra_tx_headroom + 24);
+ if (!skb) {
+ printk(KERN_DEBUG "%s: failed to allocate buffer for nullfunc "
+ "frame\n", sdata->dev->name);
+ return;
+ }
+ skb_reserve(skb, local->hw.extra_tx_headroom);
+
+ nullfunc = (struct ieee80211_hdr *) skb_put(skb, 24);
+ memset(nullfunc, 0, 24);
+ fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_NULLFUNC |
+ IEEE80211_FCTL_TODS;
+ if (powersave)
+ fc |= IEEE80211_FCTL_PM;
+ nullfunc->frame_control = cpu_to_le16(fc);
+ memcpy(nullfunc->addr1, sdata->u.sta.bssid, ETH_ALEN);
+ memcpy(nullfunc->addr2, sdata->dev->dev_addr, ETH_ALEN);
+ memcpy(nullfunc->addr3, sdata->u.sta.bssid, ETH_ALEN);
+
+ ieee80211_sta_tx(sdata->dev, skb, 0);
+}
+
+
void ieee80211_scan_completed(struct ieee80211_hw *hw)
{
struct ieee80211_local *local = hw_to_local(hw);
@@ -2544,10 +2575,12 @@ void ieee80211_scan_completed(struct iee
spin_lock_bh(&local->sub_if_lock);
list_for_each_entry(sdata, &local->sub_if_list, list) {
- netif_wake_queue(sdata->dev);
-
- if (sdata->type == IEEE80211_IF_TYPE_STA)
+ if (sdata->type == IEEE80211_IF_TYPE_STA) {
+ if (sdata->u.sta.associated)
+ ieee80211_send_nullfunc(local, sdata, 0);
ieee80211_sta_timer((unsigned long)&sdata->u.sta);
+ }
+ netif_wake_queue(sdata->dev);
}
spin_unlock_bh(&local->sub_if_lock);
@@ -2667,9 +2700,6 @@ static int ieee80211_sta_start_scan(stru
* ResultCode: SUCCESS, INVALID_PARAMETERS
*/
- /* TODO: if assoc, move to power save mode for the duration of the
- * scan */
-
if (local->sta_scanning) {
if (local->scan_dev == dev)
return 0;
@@ -2691,8 +2721,12 @@ static int ieee80211_sta_start_scan(stru
local->sta_scanning = 1;
spin_lock_bh(&local->sub_if_lock);
- list_for_each_entry(sdata, &local->sub_if_list, list)
+ list_for_each_entry(sdata, &local->sub_if_list, list) {
netif_stop_queue(sdata->dev);
+ if (sdata->type == IEEE80211_IF_TYPE_STA &&
+ sdata->u.sta.associated)
+ ieee80211_send_nullfunc(local, sdata, 1);
+ }
spin_unlock_bh(&local->sub_if_lock);
if (ssid) {
@@ -2706,7 +2740,8 @@ static int ieee80211_sta_start_scan(stru
list);
local->scan_channel_idx = 0;
local->scan_dev = dev;
- schedule_delayed_work(&local->scan_work, 0);
+ /* TODO: start scan as soon as all nullfunc frames are ACKed */
+ schedule_delayed_work(&local->scan_work, IEEE80211_CHANNEL_TIME);
return 0;
}
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