mac80211: introduce beacon-only timing data
authorJohannes Berg <johannes.berg@intel.com>
Tue, 5 Feb 2013 16:48:40 +0000 (17:48 +0100)
committerJohannes Berg <johannes.berg@intel.com>
Mon, 11 Feb 2013 17:45:00 +0000 (18:45 +0100)
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@intel.com>
include/net/mac80211.h
net/mac80211/ieee80211_i.h
net/mac80211/mlme.c
net/mac80211/scan.c
net/mac80211/trace.h

index 46e08ba92b970d289bfc5e85d817bcdd37961d3e..b9e02460d3d79518d84425e4262240daa66224a8 100644 (file)
@@ -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;
@@ -1371,6 +1379,9 @@ 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,
@@ -1399,6 +1410,7 @@ 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,
 };
 
 /**
index 8e884fcbe79b05cf39925bb03c1b3a9326b1f7b9..d794856933f21bcf102fc1229d6423c270a21844 100644 (file)
@@ -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;
index 51eca5a0cdaac02471db84e93d2aee95133de6a5..a29d09cb834cabefe19b08f841a3465376f6c874 100644 (file)
@@ -2567,6 +2567,17 @@ 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);
@@ -2725,7 +2736,7 @@ 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 */
@@ -2733,6 +2744,19 @@ 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;
        }
 
@@ -3712,10 +3736,33 @@ 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,
@@ -4041,13 +4088,23 @@ 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;
        }
index 400153f7f21fd5496496aeb0fb8a36ae28add46f..edd47d9acb99e713c0e5d3b1614cf61d1ee76274 100644 (file)
@@ -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)
index a2ca72ce3380b1d6a159821f1a0c28d688c04bb0..0bdd7aeb8958ce2c2ca57a0945bfc56c1d11c43f 100644 (file)
@@ -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));