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.\" Copyright (c) 2003 Tom Rhodes
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.\" $FreeBSD$
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.Dd December 7, 2004
.Dt WLAN 4
.Os
.Sh NAME
.Nm wlan
.Nd generic 802.11 link-layer support
.Sh SYNOPSIS
.Cd "device wlan"
.Sh DESCRIPTION
The
.Nm
module provides generic code to support 802.11 drivers.
Where a device does not directly support 802.11 functionality
this layer fills in.
The
.Nm
is required for the
.Xr wi 4 ,
.Xr an 4
and
.Xr ath 4
drivers, with other drivers to follow.
.Pp
The
.Nm
module supports multi-mode devices capable of
operating in both 2.4GHz and 5GHz bands and supports numerous
802.11 protocols: 802.11a, 802.11b, and 802.11g.
The WPA, 802.11i, and 802.1x security protocols are supported
through a combination of in-kernel code and user-mode applications.
The WME and WMM multi-media protocols are supported entirely within
the
.Nm
module but require a suitably capable hardware device.
.Pp
The
.Nm
module defines several mechanisms by which plugin modules may
be used to extend functionality.
Cryptographic support such as WEP, TKIP, and AES-CCMP are implemented
as modules that are loaded on demand (if not statically configured
into a system).
Similarly there is an authenticator framework for defining 802.11
authentication services and a framework for integrating access
control mechanisms specific to the 802.11 protocol.
.Sh DEBUGGING
If the associated interface is marked for debugging with, for example,
.Pp
.Dl "ifconfig wi0 debug"
.Pp
then messages describing the operation of the 802.11 protocol will
be sent to the console.
Complete debugging controls are available using:
.Pp
.Dl "sysctl net.wlan.X.debug=mask"
.Pp
where X is the number of the
.Nm
instance and mask is a bit-or of control bits that determine which
debugging messages to enable.
For example,
.Dl "sysctl net.wlan.0.debug=0x00200000"
.Pp
enables debugging messages related to scanning for an access point,
adhoc neighbor, or an unoccupied channel when operation as an access point.
The
.Xr 80211debug
tool provides a more user-friendly mechanism for doing the same thing.
.Pp
Many drivers will also display the contents of each 802.11 frame
sent and received when the interface is marked with
both debugging and
.Cm link2 ;
e.g.,
.Pp
.Dl "ifconfig wi0 debug link2"
.Pp
Beware however that some management frames may be processed entirely within
the device and not be received by the host.
.Sh COMPATIBILITY
The module name of
.Nm
was used to be compatible with
.Nx .
.Sh SEE ALSO
.Xr an 4 ,
.Xr ath 4 ,
.Xr awi 4 ,
.Xr netintro 4 ,
.Xr wi 4 ,
.Xr wlan_wep 4 ,
.Xr wlan_tkip 4 ,
.Xr wlan_ccmp 4 ,
.Xr wlan_xauth 4 ,
.Xr wlan_acl 4
.Sh STANDARDS
More information can be found in the IEEE 802.11 Standard.
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 5.0 .
.Sh AUTHORS
Atsushi Onoe is the author of original
.Nx
software from which this work began.
.An -nosplit
.An Sam Leffler
brought the code into
.Fx
and then rewrote it to support multi-mode devices,
802.11g, WPA/802.11i, WME, and add the extensible frameworks
for cryptographic, authentication, and access control plugins.
This manual page was written by
.An Tom Rhodes Aq trhodes@FreeBSD.org .