The
ieee80211 collection of functions are used to manage wireless network interfaces in the system which use the system's software 802.11 network stack. Most of these functions require that attachment to the stack is performed before calling. Several utility functions are also provided; these are safe to call from any driver without prior initialization.
The
ieee80211_ifattach() function attaches the wireless network interface
ic to the 802.11 network stack layer. This function must be called before using any of the
ieee80211 functions which need to store driver state across invocations. This function also performs Ethernet and BPF attachment (by calling
ether_ifattach() and
bpfattach2()) on behalf of the caller.
The
ieee80211_ifdetach() function frees any
ieee80211 structures associated with the driver, and performs Ethernet and BPF detachment on behalf of the caller.
The
ieee80211_mhz2ieee() utility function converts the frequency
freq (specified in MHz) to an IEEE 802.11 channel number. The
flags argument is a hint which specifies whether the frequency is in the 2GHz ISM band (
IEEE80211_CHAN_2GHZ) or the 5GHz band (
IEEE80211_CHAN_5GHZ); appropriate clipping of the result is then performed.
The
ieee80211_chan2ieee() function converts the channel specified in
*c to an IEEE channel number for the driver
ic. If the conversion would be invalid, an error message is printed to the system console. This function REQUIRES that the driver is hooked up to the
ieee80211 subsystem.
The
ieee80211_ieee2mhz() utility function converts the IEEE channel number
chan to a frequency (in MHz). The
flags argument is a hint which specifies whether the frequency is in the 2GHz ISM band (
IEEE80211_CHAN_2GHZ) or the 5GHz band (
IEEE80211_CHAN_5GHZ); appropriate clipping of the result is then performed.
The
ieee80211_media_init() function initializes media data structures used by the
ifmedia interface for the driver
ic. It must be called by the driver after calling
ieee80211_ifattach() and before calling most
ieee80211 functions. The
media_change and
media_stat arguments specify helper functions which will be invoked by the
ifmedia framework when the user changes or queries media options, using a command such as
ifconfig(8).
The
ieee80211_media_status() and
ieee80211_media_change() functions are device-independent handlers for
ifmedia commands and are not intended to be called directly.
The
ieee80211_watchdog() function is intended to be called from a driver's
if_watchdog routine. It is used to perform periodic cleanup of state within the software 802.11 stack, as well as timing out scans.
The
ieee80211_setmode() function is called from within the 802.11 stack to change the mode of the driver's PHY; it is not intended to be called directly.
The
ieee80211_chan2mode() function returns the PHY mode required for use with the channel
chan on the device
ic. This is typically used when selecting a rate set, to be advertised in beacons, for example.
The
ieee80211_rate2media() function converts the bit rate
rate (measured in units of 0.5Mbps) to an
ifmedia sub-type, for the device
ic running in PHY mode
mode. The
ieee80211_media2rate() performs the reverse of this conversion, returning the bit rate (in 0.5Mbps units) corresponding to an
ifmedia sub-type.