Below is the planned commit:
wtap(4): implement monitor mode and handle radiotap Implement monitor mode by simply adding IEEE80211_C_MONITOR to ic->ic_cap. To get additional informations when capturing 802.11 frames, radiotap is inserted by wtap_tx_tap() when TX and wtap_rx_tap() when RX. There are some type faults in struct wtap_rx_radiotap_header which are mainly mistakenly store unsigned values into signed integers. I have fixed them (wtap(4)) by complying with the types defined in https://www.radiotap.org/fields/defined. Becuase the struct wtap_rx_radiotap_header comes from ath(4), there may be another patch to fix the type faults in ath(4).