When wpa_supplicant is running on a Linux interface that is configured in
promiscuous mode, and it is not a member of a bridge, incoming EAPOL
packets are processed regardless of the Destination Address in the frame.
As a consequence, there are situations where wpa_supplicant replies to
EAPOL packets that are not destined for it.
This behavior seems undesired (see IEEE Std 802.1X-2010, 11.4.a), and can
be avoided by attaching a BPF filter that lets the kernel discard packets
having pkt_type equal to PACKET_OTHERHOST.
Signed-off-by: Davide Caratti <davide.caratti@gmail.com>