IEEE80211_IFATTACH(9) | Kernel Developer's Manual | IEEE80211_IFATTACH(9)

# NAME

`ieee80211_ifattach`, `ieee80211_ifdetach`, `ieee80211_mhz2ieee`, `ieee80211_chan2ieee`, `ieee80211_ieee2mhz`, `ieee80211_media_init`, `ieee80211_media_change`, `ieee80211_media_status`, `ieee80211_watchdog`, `ieee80211_setmode`, `ieee80211_chan2mode`, `ieee80211_rate2media`, `ieee80211_media2rate`, `ieee80211_rate2plcp`, `ieee80211_plcp2rate` — core 802.11 network stack functions

# SYNOPSIS

`#include <net80211/ieee80211_var.h>`
`#include <net80211/ieee80211_proto.h>`

void
`ieee80211_ifattach`(struct ifnet *ifp);

void
`ieee80211_ifdetach`(struct ifnet *ifp);

u_int
`ieee80211_mhz2ieee`(u_int freq, u_int flags);

u_int
`ieee80211_chan2ieee`(struct ieee80211com *ic, const struct ieee80211_channel *c);

u_int
`ieee80211_ieee2mhz`(u_int chan, u_int flags);

void
`ieee80211_media_init`(struct ifnet *ifp, ifm_change_cb_t media_change, ifm_stat_cb_t media_stat);

int
`ieee80211_media_change`(struct ifnet *ifp);

void
`ieee80211_media_status`(struct ifnet *ifp, struct ifmediareq *imr);

void
`ieee80211_watchdog`(struct ifnet *ifp);

int
`ieee80211_setmode`(struct ieee80211com *ic, enum ieee80211_phymode mode);

enum ieee80211_phymode
`ieee80211_chan2mode`(struct ieee80211com *ic, const struct ieee80211_channel *chan);

int
`ieee80211_rate2media`(struct ieee80211com *ic, int rate, enum ieee80211_phymode mode);

int
`ieee80211_media2rate`(int mword);

u_int8_t
`ieee80211_rate2plcp`(u_int8_t rate, enum ieee80211_phymode mode);

u_int8_t
`ieee80211_plcp2rate`(u_int8_t plcp, enum ieee80211_phymode mode);

# DESCRIPTION

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 network interface ifp 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. The struct ifnet instance pointed to by ifp MUST be an instance of struct ieee80211com, with various fields initialized to tell `ieee80211` about its capabilities. This function performs Ethernet and BPF attachment (by calling `ether_ifattach`() and `bpfattach`()) on behalf of the caller. It also implements the ifmedia interface.

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 ifp. 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`() function performs the reverse of this conversion, returning the bit rate (in 0.5Mbps units) corresponding to an ifmedia sub-type.

The `ieee80211_rate2plcp`() function converts the bit rate rate (measured in units of 0.5Mbps) to a plcp signal (in msb-first R4-R1 format). The `ieee80211_plcp2rate`() function performs the reverse of this conversion, returning the bit rate (in 0.5Mbps units) corresponding to a plcp signal (in msb-first R4-R1 format).

# SEE ALSO

ifmedia(4), ieee80211_crypto(9), ieee80211_input(9), ieee80211_ioctl(9), ieee80211_node(9), ieee80211_output(9), ieee80211_proto(9), ieee80211_radiotap(9), rssadapt(9)

# HISTORY

The `ieee80211` series of functions first appeared in NetBSD 1.5, and were later ported to FreeBSD 4.6 and OpenBSD 3.6.

# AUTHORS

This man page was written by Bruce M. Simpson <bms@FreeBSD.org> and Darron Broad <darron@kewl.org>.

March 29, 2022 | Debian