From: Johannes Berg <johannes.berg@xxxxxxxxx>
In order to be able to predict the next DTIM TBTT
in the driver, add the ability to use timing data
from beacons only with the new hardware flag
IEEE80211_HW_TIMING_BEACON_ONLY and the BSS info
value sync_dtim_count which is only valid if the
timing data came from a beacon. The data can only
come from a beacon, and if no beacon was received
before association it is updated later together
with the DTIM count notification.
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
include/net/mac80211.h | 14 +++++++++-
net/mac80211/ieee80211_i.h | 2 +-
net/mac80211/mlme.c | 65 +++++++++++++++++++++++++++++++++++++++++++---
net/mac80211/scan.c | 5 +++-
net/mac80211/trace.h | 2 ++
5 files changed, 81 insertions(+), 7 deletions(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 7d9a4f7..d7dc907 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -277,9 +277,16 @@ enum ieee80211_rssi_event {
* valid in station mode only if after the driver was notified
* with the %BSS_CHANGED_DTIM_PERIOD flag, will be non-zero then.
* @sync_tsf: last beacon's/probe response's TSF timestamp (could be old
- * as it may have been received during scanning long ago)
+ * as it may have been received during scanning long ago). If the
+ * HW flag %IEEE80211_HW_TIMING_BEACON_ONLY is set, then this can
+ * only come from a beacon, but might not become valid until after
+ * association when a beacon is received (which is notified with the
+ * %BSS_CHANGED_DTIM flag.)
* @sync_device_ts: the device timestamp corresponding to the sync_tsf,
* the driver/device can use this to calculate synchronisation
+ * (see @sync_tsf)
+ * @sync_dtim_count: Only valid when %IEEE80211_HW_TIMING_BEACON_ONLY
+ * is requested, see @sync_tsf/@sync_device_ts.
* @beacon_int: beacon interval
* @assoc_capability: capabilities taken from assoc resp
* @basic_rates: bitmap of basic rates, each bit stands for an
@@ -331,6 +338,7 @@ struct ieee80211_bss_conf {
u16 assoc_capability;
u64 sync_tsf;
u32 sync_device_ts;
+ u8 sync_dtim_count;
u32 basic_rates;
int mcast_rate[IEEE80211_NUM_BANDS];
u16 ht_operation_mode;
@@ -1376,6 +1384,9 @@ struct ieee80211_tx_control {
* @IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF: Use the P2P Device address for any
* P2P Interface. This will be honoured even if more than one interface
* is supported.
+ *
+ * @IEEE80211_HW_TIMING_BEACON_ONLY: Use sync timing from beacon frames
+ * only, to allow getting TBTT of a DTIM beacon.
*/
enum ieee80211_hw_flags {
IEEE80211_HW_HAS_RATE_CONTROL = 1<<0,
@@ -1404,6 +1415,7 @@ enum ieee80211_hw_flags {
IEEE80211_HW_TX_AMPDU_SETUP_IN_HW = 1<<23,
IEEE80211_HW_SCAN_WHILE_IDLE = 1<<24,
IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF = 1<<25,
+ IEEE80211_HW_TIMING_BEACON_ONLY = 1<<26,
};
/**
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 4631de0..0aee941 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -86,7 +86,7 @@ struct ieee80211_fragment_entry {
struct ieee80211_bss {
- u32 device_ts;
+ u32 device_ts_beacon, device_ts_presp;
bool wmm_used;
bool uapsd_supported;
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index b49c484..735859e 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2590,6 +2590,17 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems);
ifmgd->assoc_data->have_beacon = true;
ifmgd->assoc_data->need_beacon = false;
+ if (local->hw.flags & IEEE80211_HW_TIMING_BEACON_ONLY) {
+ sdata->vif.bss_conf.sync_tsf =
+ le64_to_cpu(mgmt->u.beacon.timestamp);
+ sdata->vif.bss_conf.sync_device_ts =
+ rx_status->device_timestamp;
+ if (elems.tim)
+ sdata->vif.bss_conf.sync_dtim_count =
+ elems.tim->dtim_count;
+ else
+ sdata->vif.bss_conf.sync_dtim_count = 0;
+ }
/* continue assoc process */
ifmgd->assoc_data->timeout = jiffies;
run_again(ifmgd, ifmgd->assoc_data->timeout);
@@ -2748,7 +2759,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
/*
* If we haven't had a beacon before, tell the driver about the
- * DTIM period now.
+ * DTIM period (and beacon timing if desired) now.
*/
if (!bss_conf->dtim_period) {
/* a few bogus AP send dtim_period = 0 or no TIM IE */
@@ -2756,6 +2767,19 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
bss_conf->dtim_period = elems.tim->dtim_period ?: 1;
else
bss_conf->dtim_period = 1;
+
+ if (local->hw.flags & IEEE80211_HW_TIMING_BEACON_ONLY) {
+ sdata->vif.bss_conf.sync_tsf =
+ le64_to_cpu(mgmt->u.beacon.timestamp);
+ sdata->vif.bss_conf.sync_device_ts =
+ rx_status->device_timestamp;
+ if (elems.tim)
+ sdata->vif.bss_conf.sync_dtim_count =
+ elems.tim->dtim_count;
+ else
+ sdata->vif.bss_conf.sync_dtim_count = 0;
+ }
+
changed |= BSS_CHANGED_DTIM_PERIOD;
}
@@ -3738,10 +3762,33 @@ static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata,
/* set timing information */
sdata->vif.bss_conf.beacon_int = cbss->beacon_interval;
rcu_read_lock();
- ies = rcu_dereference(cbss->ies);
- sdata->vif.bss_conf.sync_tsf = ies->tsf;
+ ies = rcu_dereference(cbss->beacon_ies);
+ if (ies) {
+ const u8 *tim_ie;
+
+ sdata->vif.bss_conf.sync_tsf = ies->tsf;
+ sdata->vif.bss_conf.sync_device_ts =
+ bss->device_ts_beacon;
+ tim_ie = cfg80211_find_ie(WLAN_EID_TIM,
+ ies->data, ies->len);
+ if (tim_ie && tim_ie[1] >= 2)
+ sdata->vif.bss_conf.sync_dtim_count = tim_ie[2];
+ else
+ sdata->vif.bss_conf.sync_dtim_count = 0;
+ } else if (!(local->hw.flags &
+ IEEE80211_HW_TIMING_BEACON_ONLY)) {
+ ies = rcu_dereference(cbss->proberesp_ies);
+ /* must be non-NULL since beacon IEs were NULL */
+ sdata->vif.bss_conf.sync_tsf = ies->tsf;
+ sdata->vif.bss_conf.sync_device_ts =
+ bss->device_ts_presp;
+ sdata->vif.bss_conf.sync_dtim_count = 0;
+ } else {
+ sdata->vif.bss_conf.sync_tsf = 0;
+ sdata->vif.bss_conf.sync_device_ts = 0;
+ sdata->vif.bss_conf.sync_dtim_count = 0;
+ }
rcu_read_unlock();
- sdata->vif.bss_conf.sync_device_ts = bss->device_ts;
/* tell driver about BSSID, basic rates and timing */
ieee80211_bss_info_change_notify(sdata,
@@ -4067,13 +4114,23 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
const u8 *tim_ie = cfg80211_find_ie(WLAN_EID_TIM,
beacon_ies->data,
beacon_ies->len);
+ u8 dtim_count = 0;
+
if (tim_ie && tim_ie[1] >= sizeof(struct ieee80211_tim_ie)) {
const struct ieee80211_tim_ie *tim;
tim = (void *)(tim_ie + 2);
ifmgd->dtim_period = tim->dtim_period;
+ dtim_count = tim->dtim_count;
}
assoc_data->have_beacon = true;
assoc_data->timeout = jiffies;
+
+ if (local->hw.flags & IEEE80211_HW_TIMING_BEACON_ONLY) {
+ sdata->vif.bss_conf.sync_tsf = beacon_ies->tsf;
+ sdata->vif.bss_conf.sync_device_ts =
+ bss->device_ts_beacon;
+ sdata->vif.bss_conf.sync_dtim_count = dtim_count;
+ }
} else {
assoc_data->timeout = jiffies;
}
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 400153f..edd47d9 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -80,7 +80,10 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
bss = (void *)cbss->priv;
- bss->device_ts = rx_status->device_timestamp;
+ if (beacon)
+ bss->device_ts_beacon = rx_status->device_timestamp;
+ else
+ bss->device_ts_presp = rx_status->device_timestamp;
if (elems->parse_error) {
if (beacon)
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index 6ca53d6..dd2b80a 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -340,6 +340,7 @@ TRACE_EVENT(drv_bss_info_changed,
__field(u16, assoc_cap)
__field(u64, sync_tsf)
__field(u32, sync_device_ts)
+ __field(u8, sync_dtim_count)
__field(u32, basic_rates)
__array(int, mcast_rate, IEEE80211_NUM_BANDS)
__field(u16, ht_operation_mode)
@@ -379,6 +380,7 @@ TRACE_EVENT(drv_bss_info_changed,
__entry->assoc_cap = info->assoc_capability;
__entry->sync_tsf = info->sync_tsf;
__entry->sync_device_ts = info->sync_device_ts;
+ __entry->sync_dtim_count = info->sync_dtim_count;
__entry->basic_rates = info->basic_rates;
memcpy(__entry->mcast_rate, info->mcast_rate,
sizeof(__entry->mcast_rate));
--
1.8.0
--
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