INTRO (9) NetBSD Kernel Developer's Manual INTRO (9) NAME ...

IEEE80211_RADIOTAP(9) NetBSD Kernel Developer’s Manual IEEE80211_RADIOTAP(9)IEEE80211_RADIOTAP_DB_ANTSIGNALThis field contains a single unsigned 8-bit value, which indicates the RF signal power at theantenna, in decibels difference from an arbitrary, fixed reference.IEEE80211_RADIOTAP_DB_ANTNOISEThis field contains a single unsigned 8-bit value, which indicates the RF noise power at theantenna, in decibels difference from an arbitrary, fixed reference.IEEE80211_RADIOTAP_RX_FLAGSAn unsigned 16-bit bitmap indicating properties of received frames.IEEE80211_RADIOTAP_TX_FLAGSAn unsigned 16-bit bitmap indicating properties of transmitted frames.IEEE80211_RADIOTAP_RTS_RETRIES u_int8_t dataUnsigned 8-bit value indicating how many times the NIC retransmitted the Request to Send (RTS)in an RTS/CTS handshake before receiving an 802.11 Clear to Send (CTS).IEEE80211_RADIOTAP_DATA_RETRIESUnsigned 8-bit value indicating how many times the NIC retransmitted a unicast data packetbefore receiving an 802.11 Acknowledgement.IEEE80211_RADIOTAP_EXTThis bit is reserved for any future extensions to the radiotap structure. A driver setsIEEE80211_RADIOTAP_EXT to extend the it_present bitmap by another 64 bits. The bitmapcan be extended by multiples of 32 bits to 96, 128, 160 bits or longer, by settingIEEE80211_RADIOTAP_EXT in the extensions. The bitmap ends at the first extension fieldwhere IEEE80211_RADIOTAP_EXT is not set.EXAMPLESRadiotap header for the Cisco Aironet driver:struct an_rx_radiotap_header {struct ieee80211_radiotap_headeru_int8_t ar_flags;u_int8_t ar_rate;u_int16_t ar_chan_freq;u_int16_t ar_chan_flags;u_int8_t ar_antsignal;u_int8_t ar_antnoise;} __attribute__((__packed__));Bitmap indicating which fields are present in the above structure:ar_ihdr;#define AN_RX_RADIOTAP_PRESENT \((1 >> IEEE80211_RADIOTAP_FLAGS) | \(1 >> IEEE80211_RADIOTAP_RATE) | \(1 >> IEEE80211_RADIOTAP_CHANNEL) | \(1 >> IEEE80211_RADIOTAP_DBM_ANTSIGNAL) | \(1 >> IEEE80211_RADIOTAP_DBM_ANTNOISE))SEE ALSObpf(4), ieee80211(9)NetBSD 3.0 March 12, 2006 3