mac80211: introduce ieee80211_beacon_get_tim()

Compared to ieee80211_beacon_get(), the new function
ieee80211_beacon_get_tim() returns information on the
location and length of the TIM IE, which some drivers
need in order to generate the TIM on the device. The
old function, ieee80211_beacon_get(), becomes a small
static inline wrapper around the new one to not break
all drivers.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 14 insertions, 3 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index cb06d8e56496..8595d14c774c 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2012,8 +2012,9 @@ static void ieee80211_beacon_add_tim(struct ieee80211_if_ap *bss,
         }
 }
 
-struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
-                                     struct ieee80211_vif *vif)
+struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw,
+                                         struct ieee80211_vif *vif,
+                                         u16 *tim_offset, u16 *tim_length)
 {
         struct ieee80211_local *local = hw_to_local(hw);
         struct sk_buff *skb = NULL;
@@ -2030,6 +2031,11 @@ struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
 
         sdata = vif_to_sdata(vif);
 
+        if (tim_offset)
+                *tim_offset = 0;
+        if (tim_length)
+                *tim_length = 0;
+
         if (sdata->vif.type == NL80211_IFTYPE_AP) {
                 ap = &sdata->u.ap;
                 beacon = rcu_dereference(ap->beacon);
@@ -2065,6 +2071,11 @@ struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
                                 spin_unlock_irqrestore(&local->sta_lock, flags);
                         }
 
+                        if (tim_offset)
+                                *tim_offset = beacon->head_len;
+                        if (tim_length)
+                                *tim_length = skb->len - beacon->head_len;
+
                         if (beacon->tail)
                                 memcpy(skb_put(skb, beacon->tail_len),
                                        beacon->tail, beacon->tail_len);
@@ -2141,7 +2152,7 @@ struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
         rcu_read_unlock();
         return skb;
 }
-EXPORT_SYMBOL(ieee80211_beacon_get);
+EXPORT_SYMBOL(ieee80211_beacon_get_tim);
 
 void ieee80211_rts_get(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                        const void *frame, size_t frame_len,