The 802.11 header length is affected by the wireless mode (WDS or not) and
type (QoS or not). We should use the variable hdr_len instead of the
hard coded IEEE80211_3ADDR_LEN, otherwise we may touch invalid memory.
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>