wireless: add ieee80211_amsdu_to_8023s

Move the A-MSDU handling code from mac80211 to cfg80211 so that more
drivers can use it. The new created function ieee80211_amsdu_to_8023s
converts an A-MSDU frame to a list of 802.3 frames.

Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 0884b9a..542a477 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1578,7 +1578,7 @@
  * @addr: the device MAC address
  * @iftype: the virtual interface type
  */
-int ieee80211_data_to_8023(struct sk_buff *skb, u8 *addr,
+int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
 			   enum nl80211_iftype iftype);
 
 /**
@@ -1589,10 +1589,28 @@
  * @bssid: the network bssid (used only for iftype STATION and ADHOC)
  * @qos: build 802.11 QoS data frame
  */
-int ieee80211_data_from_8023(struct sk_buff *skb, u8 *addr,
+int ieee80211_data_from_8023(struct sk_buff *skb, const u8 *addr,
 			     enum nl80211_iftype iftype, u8 *bssid, bool qos);
 
 /**
+ * ieee80211_amsdu_to_8023s - decode an IEEE 802.11n A-MSDU frame
+ *
+ * Decode an IEEE 802.11n A-MSDU frame and convert it to a list of
+ * 802.3 frames. The @list will be empty if the decode fails. The
+ * @skb is consumed after the function returns.
+ *
+ * @skb: The input IEEE 802.11n A-MSDU frame.
+ * @list: The output list of 802.3 frames. It must be allocated and
+ *	initialized by by the caller.
+ * @addr: The device MAC address.
+ * @iftype: The device interface type.
+ * @extra_headroom: The hardware extra headroom for SKBs in the @list.
+ */
+void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
+			      const u8 *addr, enum nl80211_iftype iftype,
+			      const unsigned int extra_headroom);
+
+/**
  * cfg80211_classify8021d - determine the 802.1p/1d tag for a data frame
  * @skb: the data frame
  */