cfg80211: move TSF into IEs

While technically the TSF isn't an IE, it can be
necessary to distinguish between the TSF from a
beacon and a probe response, in particular in
order to know the next DTIM TBTT, as not all APs
are spec compliant wrt. TSF==0 being a DTIM TBTT
and thus the DTIM count needs to be taken into
account as well.

To allow this, move the TSF into the IE struct
so it can be known whence it came.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 71c55cc0f7b6..055fa9436e95 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -242,6 +242,8 @@ static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
         u32 basic_rates;
         int i, j;
         u16 beacon_int = cbss->beacon_interval;
+        const struct cfg80211_bss_ies *ies;
+        u64 tsf;
 
         lockdep_assert_held(&sdata->u.ibss.mtx);
 
@@ -265,13 +267,17 @@ static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
                 }
         }
 
+        rcu_read_lock();
+        ies = rcu_dereference(cbss->ies);
+        tsf = ies->tsf;
+        rcu_read_unlock();
+
         __ieee80211_sta_join_ibss(sdata, cbss->bssid,
                                   beacon_int,
                                   cbss->channel,
                                   basic_rates,
                                   cbss->capability,
-                                  cbss->tsf,
-                                  false);
+                                  tsf, false);
 }
 
 static struct sta_info *ieee80211_ibss_finish_sta(struct sta_info *sta,
@@ -535,8 +541,8 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 
         cbss = container_of((void *)bss, struct cfg80211_bss, priv);
 
-        /* was just updated in ieee80211_bss_info_update */
-        beacon_timestamp = cbss->tsf;
+        /* same for beacon and probe response */
+        beacon_timestamp = le64_to_cpu(mgmt->u.beacon.timestamp);
 
         /* check if we need to merge IBSS */