ENUM 
IEEE80211_FILTE(9) The basic mac80211 driver inte ENUM IEEE80211_FILTE(9) NAME
enum_ieee80211_filter_flags - hardware filter flags SYNOPSIS
enum ieee80211_filter_flags { FIF_PROMISC_IN_BSS, FIF_ALLMULTI, FIF_FCSFAIL, FIF_PLCPFAIL, FIF_BCN_PRBRESP_PROMISC, FIF_CONTROL, FIF_OTHER_BSS, FIF_PSPOLL, FIF_PROBE_REQ }; CONSTANTS
FIF_PROMISC_IN_BSS promiscuous mode within your BSS, think of the BSS as your network segment and then this corresponds to the regular ethernet device promiscuous mode. FIF_ALLMULTI pass all multicast frames, this is used if requested by the user or if the hardware is not capable of filtering by multicast address. FIF_FCSFAIL pass frames with failed FCS (but you need to set the RX_FLAG_FAILED_FCS_CRC for them) FIF_PLCPFAIL pass frames with failed PLCP CRC (but you need to set the RX_FLAG_FAILED_PLCP_CRC for them FIF_BCN_PRBRESP_PROMISC This flag is set during scanning to indicate to the hardware that it should not filter beacons or probe responses by BSSID. Filtering them can greatly reduce the amount of processing mac80211 needs to do and the amount of CPU wakeups, so you should honour this flag if possible. FIF_CONTROL pass control frames (except for PS Poll), if PROMISC_IN_BSS is not set then only those addressed to this station. FIF_OTHER_BSS pass frames destined to other BSSes FIF_PSPOLL pass PS Poll frames, if PROMISC_IN_BSS is not set then only those addressed to this station. FIF_PROBE_REQ pass probe request frames HW QUEUE CONTROL
These flags determine what the filter in hardware should be programmed to let through and what should not be passed to the stack. It is always safe to pass more frames than requested, but this has negative impact on power consumption. AUTHOR
Johannes Berg <johannes@sipsolutions.net> Author. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 ENUM IEEE80211_FILTE(9)