mac80211: sync dtim_count to TSF

On starting a mesh or AP BSS, the interface dtim_count
countdown should match that of the driver TSF.

Signed-off-by: Thomas Pedersen <twpedersen@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

5 files changed, 46 insertions, 0 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index fd1020e791d8..f9ae9b85d4c1 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1035,6 +1035,7 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
                 return err;
         }
 
+        ieee80211_recalc_dtim(local, sdata);
         ieee80211_bss_info_change_notify(sdata, changed);
 
         netif_carrier_on(dev);
diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c
index b62cbe82954c..ebf80f3abd83 100644
--- a/net/mac80211/debugfs_netdev.c
+++ b/net/mac80211/debugfs_netdev.c
@@ -474,6 +474,7 @@ static ssize_t ieee80211_if_parse_tsf(
                 }
         }
 
+        ieee80211_recalc_dtim(local, sdata);
         return buflen;
 }
 IEEE80211_IF_FILE_RW(tsf);
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 953b9e294547..3701930c6649 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1800,6 +1800,8 @@ ieee80211_cs_get(struct ieee80211_local *local, u32 cipher,
 int ieee80211_cs_headroom(struct ieee80211_local *local,
                           struct cfg80211_crypto_settings *crypto,
                           enum nl80211_iftype iftype);
+void ieee80211_recalc_dtim(struct ieee80211_local *local,
+                           struct ieee80211_sub_if_data *sdata);
 
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index 5a74b249ba35..5b919cab1de0 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -807,6 +807,7 @@ int ieee80211_start_mesh(struct ieee80211_sub_if_data *sdata)
                 return -ENOMEM;
         }
 
+        ieee80211_recalc_dtim(local, sdata);
         ieee80211_bss_info_change_notify(sdata, changed);
 
         netif_carrier_on(sdata->dev);
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index df00f1978a77..676dc0967f37 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2734,3 +2734,44 @@ int ieee80211_parse_p2p_noa(const struct ieee80211_p2p_noa_attr *attr,
         return ret;
 }
 EXPORT_SYMBOL(ieee80211_parse_p2p_noa);
+
+void ieee80211_recalc_dtim(struct ieee80211_local *local,
+                           struct ieee80211_sub_if_data *sdata)
+{
+        u64 tsf = drv_get_tsf(local, sdata);
+        u64 dtim_count = 0;
+        u16 beacon_int = sdata->vif.bss_conf.beacon_int * 1024;
+        u8 dtim_period = sdata->vif.bss_conf.dtim_period;
+        struct ps_data *ps;
+        u8 bcns_from_dtim;
+
+        if (tsf == -1ULL || !beacon_int || !dtim_period)
+                return;
+
+        if (sdata->vif.type == NL80211_IFTYPE_AP ||
+            sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
+                if (!sdata->bss)
+                        return;
+
+                ps = &sdata->bss->ps;
+        } else if (ieee80211_vif_is_mesh(&sdata->vif)) {
+                ps = &sdata->u.mesh.ps;
+        } else {
+                return;
+        }
+
+        /*
+         * actually finds last dtim_count, mac80211 will update in
+         * __beacon_add_tim().
+         * dtim_count = dtim_period - (tsf / bcn_int) % dtim_period
+         */
+        do_div(tsf, beacon_int);
+        bcns_from_dtim = do_div(tsf, dtim_period);
+        /* just had a DTIM */
+        if (!bcns_from_dtim)
+                dtim_count = 0;
+        else
+                dtim_count = dtim_period - bcns_from_dtim;
+
+        ps->dtim_count = dtim_count;
+}