empty/unused octets to fill out the data time slot. The value is constrained
by math to 0 for <= 5.5Mb, 0-1 for 11Mb, and 0-2 for 22Mb. It is used to
signal to the MAC that there is residue.
For use by the subroutine ieee80211_compute_duration, add struct
ieee80211_duration, and #define a number of microsecond constants
used for the transmit timing of 802.11 packets.
Add the subroutine ieee80211_compute_duration, which computes for
any packet the appropriate 802.11 Duration field, the PLCP Length
field, as well as the Duration and Length fields for an RTS frame.
atw(4), rtw(4), future drivers, and possibly ath(4) will share
ieee80211_compute_duration.
* Add Kevin Lahey's power-saving support from the old 802.11 layer
* Support for frequency-hopping PHYs
* Add support frequency-hopping PHY mode, IFM_IEEE80211_FH
* Add channel flags for frequency-hopping
* Add mode<->media mappings in for FH PHY in ieee80211_media2rate
and ieee80211_rate2media
* Stop using IFM_MAKEMODE macro since the mode constants
(e.g., IFM_IEEE80211_11A) are pre-shifted in sys/net/if_media.h
* Add some PLCP constants.
mycroft