NAME

       wlan — generic 802.11 link-layer support

SYNOPSIS

       device wlan

DESCRIPTION

       The  wlan  module  provides  generic  code  to  support 802.11 drivers.  Where a device does not directly
       support 802.11 functionality this layer fills in.  The wlan module  is  required  by  all  native  802.11
       drivers as well as the ndis(4) support.

       wlan supports multi-mode devices capable of operating in both 2.4GHz and 5GHz bands and supports numerous
       802.11  standards:  802.11a,  802.11b,  802.11g, 802.11n, and 802.11s (Draft 3.0).  The WPA, 802.11i, and
       802.1x  security  protocols  are  supported  through  a  combination  of  in-kernel  code  and  user-mode
       applications.   The  WME/WMM  multi-media  protocols  are  supported  entirely within the wlan module but
       require a suitably capable hardware device.  Likewise the 802.11h  specification  is  supported  only  by
       suitably capable devices.

       Drivers  provide 802.11 functionality through wlan interfaces that are created at runtime using interface
       cloning.  This is done with the ifconfig(8) create command or using the wlans_IFX variable in rc.conf(5).
       Some drivers support the creation of multiple wlan interfaces that share the same underlying device; this
       is the way by which ``multi-bss support'' is provided but it can also be used to  create  WDS  links  and
       other interesting applications.

       There are several types of wlan interfaces that may be created:

       sta      A client station in an infrastructure bss (i.e. one that associates to an access point).

       hostap   An access point in an infrastructure bss.

       mesh     A mesh station in an MBSS network.

       adhoc    A station in an IBSS network.

       ahdemo   A  station  operating in ``adhoc demo mode''.  This is essentially an IBSS station that does not
                use management frames (e.g. no beacons are transmitted).   An  ahdemo  interface  is  especially
                useful for applications that want to transmit and receive raw 802.11 packets.

       monitor  An interface used exclusively for capturing 802.11 frames.  In particular this specified to have
                read-only  properties  which  enables it to be operated on frequencies where one would otherwise
                not be allowed.

       wds      A station that passes 4-address 802.11 traffic for the  purpose  of  tunneling  traffic  over  a
                wireless  link.   Typically this station would share the same MAC address as a hostap interface.
                It may be possible to create wds interfaces without a companion hostap interface but that is not
                guaranteed; one may need to create a hostap interface that does not send  beacon  frames  before
                wds interfaces may be created.

       Note that an interface's type cannot be changed once it is created.

       wlan  defines  several  mechanisms  by  which  plugin  modules  may  be used to extend its functionality.
       Cryptographic support such as WEP, TKIP, and AES-CCMP are  implemented  as  standalone  modules  (if  not
       statically  configured  into  a  system)  that  register  with wlan.  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.

DEBUGGING

       If  the  IEEE80211_DEBUG option is included in the kernel configuration, debugging controls are available
       using:

             sysctl net.wlan.X.debug=mask

       where X is the number of the wlan instance and mask is a bit-or of  control  bits  that  determine  which
       debugging messages to enable.  For example,

             sysctl net.wlan.0.debug=0x00200000

       enables  debugging  messages  related  to  scanning for an access point, adhoc neighbor, or an unoccupied
       channel when operation as an access point.  The wlandebug(8) tool provides a more user-friendly mechanism
       for doing the same thing.  Note that

             sysctl net.wlan.debug=mask

       defines the initial value of the debugging flags for each cloned wlan interface; this is useful to enable
       debug messages during interface creation.

COMPATIBILITY

       The module name of wlan was used to be compatible with NetBSD.

       Mesh stations follow the 802.11s Draft 3.0 specification which is not ratified  and  subject  to  change.
       Beware  that  this  specification  is incompatible with earlier drafts; and stations implementing earlier
       drafts (e.g. Linux) may not interoperate.

SEE ALSO

       an(4), ath(4), bwi(4), bwn(4), ipw(4), iwi(4), iwn(4),  malo(4),  mwl(4),  netintro(4),  ral(4),  rum(4),
       run(4),  uath(4), upgt(4), ural(4), urtw(4), wi(4), wlan_acl(4), wlan_ccmp(4), wlan_tkip(4), wlan_wep(4),
       wlan_xauth(4), wpi(4), zyd(4)

STANDARDS

       More information can be found in the IEEE 802.11 Standards.

HISTORY

       The wlan driver first appeared in FreeBSD 5.0.

AUTHORS

       Atsushi Onoe is the author of original NetBSD software from which this work began.  Sam  Leffler  brought
       the  code  into FreeBSD and then rewrote it to support multi-mode devices, 802.11g, 802.11n, WPA/802.11i,
       WME, multi-bss, and add the extensible frameworks for cryptographic, authentication, and  access  control
       plugins.  This manual page was written by Tom Rhodes <trhodes@FreeBSD.org>.

Debian                                          February 22, 2012                                        WLAN(4)