1.\" 2.\" Copyright (c) 2003 Tom Rhodes 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd February 22, 2012 29.Dt WLAN 4 30.Os 31.Sh NAME 32.Nm wlan 33.Nd generic 802.11 link-layer support 34.Sh SYNOPSIS 35.Cd "device wlan" 36.Sh DESCRIPTION 37The 38.Nm 39module provides generic code to support 802.11 drivers. 40Where a device does not directly support 802.11 functionality 41this layer fills in. 42The 43.Nm 44module is required by all native 802.11 drivers as well as the 45.Xr ndis 4 46support. 47.Pp 48.Nm 49supports multi-mode devices capable of 50operating in both 2.4GHz and 5GHz bands and supports numerous 51802.11 standards: 802.11a, 802.11b, 802.11g, 802.11n, and 802.11s (Draft 3.0). 52The WPA, 802.11i, and 802.1x security protocols are supported 53through a combination of in-kernel code and user-mode applications. 54The WME/WMM multi-media protocols are supported entirely within 55the 56.Nm 57module but require a suitably capable hardware device. 58Likewise the 802.11h specification is supported only by suitably 59capable devices. 60.Pp 61Drivers provide 802.11 functionality through 62.Nm 63interfaces that are created at runtime using interface cloning. 64This is done with the 65.Xr ifconfig 8 66.Cm create 67command or using the 68.Va wlans_IFX 69variable in 70.Xr rc.conf 5 . 71Some drivers support the creation of multiple 72.Nm 73interfaces that share the same underlying device; 74this is the way by which ``multi-bss support'' is provided but it 75can also be used to create WDS links and other interesting applications. 76.Pp 77There are several types of 78.Nm 79interfaces that may be created: 80.Bl -tag -width monitor 81.It Cm sta 82A client station in an infrastructure bss 83(i.e. one that associates to an access point). 84.It Cm hostap 85An access point in an infrastructure bss. 86.It Cm mesh 87A mesh station in an MBSS network. 88.It Cm adhoc 89A station in an IBSS network. 90.It Cm ahdemo 91A station operating in ``adhoc demo mode''. 92This is essentially an IBSS station that does not use management 93frames (e.g. no beacons are transmitted). 94An 95.Cm ahdemo 96interface is especially useful for applications that want to transmit 97and receive raw 802.11 packets. 98.It Cm monitor 99An interface used exclusively for capturing 802.11 frames. 100In particular this specified to have read-only properties 101which enables it to be operated on frequencies where one 102would otherwise not be allowed. 103.It Cm wds 104A station that passes 4-address 802.11 traffic for the purpose 105of tunneling traffic over a wireless link. 106Typically this station would share the same MAC address as a 107.Cm hostap 108interface. 109It may be possible to create 110.Cm wds 111interfaces without a companion 112.Cm hostap 113interface but that is not guaranteed; one may need to create a 114.Cm hostap 115interface that does not send beacon frames before 116.Cm wds 117interfaces may be created. 118.El 119.Pp 120Note that an interface's type cannot be changed once it is created. 121.Pp 122.Nm 123defines several mechanisms by which plugin modules may 124be used to extend its functionality. 125Cryptographic support such as WEP, TKIP, and AES-CCMP are implemented 126as standalone modules (if not statically configured into a system) 127that register with 128.Nm . 129Similarly there is an authenticator framework for defining 802.11 130authentication services and a framework for integrating access 131control mechanisms specific to the 802.11 protocol. 132.Sh DEBUGGING 133If the 134.Dv IEEE80211_DEBUG 135option is included in the kernel configuration, 136debugging controls are available using: 137.Pp 138.Dl "sysctl net.wlan.X.debug=mask" 139.Pp 140where 141.Ar X 142is the number of the 143.Nm 144instance and mask is a bit-or of control bits that determine which 145debugging messages to enable. 146For example, 147.Pp 148.Dl "sysctl net.wlan.0.debug=0x00200000" 149.Pp 150enables debugging messages related to scanning for an access point, 151adhoc neighbor, or an unoccupied channel when operation as an access point. 152The 153.Xr wlandebug 8 154tool provides a more user-friendly mechanism for doing the same thing. 155Note that 156.Pp 157.Dl "sysctl net.wlan.debug=mask" 158.Pp 159defines the initial value of the debugging flags for each cloned 160.Nm 161interface; this is useful to enable debug messages during interface creation. 162.Sh COMPATIBILITY 163The module name of 164.Nm 165was used to be compatible with 166.Nx . 167.Pp 168Mesh stations follow the 802.11s Draft 3.0 specification which is 169not ratified and subject to change. 170Beware that this specification is incompatible with earlier drafts; 171and stations implementing earlier drafts (e.g. Linux) 172may not interoperate. 173.Sh SEE ALSO 174.Xr an 4 , 175.Xr ath 4 , 176.Xr bwi 4 , 177.Xr bwn 4 , 178.Xr ipw 4 , 179.Xr iwi 4 , 180.Xr iwn 4 , 181.Xr malo 4 , 182.Xr mwl 4 , 183.Xr netintro 4 , 184.Xr ral 4 , 185.Xr rum 4 , 186.Xr run 4 , 187.Xr uath 4 , 188.Xr upgt 4 , 189.Xr ural 4 , 190.Xr urtw 4 , 191.Xr wi 4 , 192.Xr wlan_acl 4 , 193.Xr wlan_ccmp 4 , 194.Xr wlan_tkip 4 , 195.Xr wlan_wep 4 , 196.Xr wlan_xauth 4 , 197.Xr wpi 4 , 198.Xr zyd 4 199.Sh STANDARDS 200More information can be found in the IEEE 802.11 Standards. 201.Sh HISTORY 202The 203.Nm 204driver first appeared in 205.Fx 5.0 . 206.Sh AUTHORS 207Atsushi Onoe is the author of original 208.Nx 209software from which this work began. 210.An -nosplit 211.An Sam Leffler 212brought the code into 213.Fx 214and then rewrote it to support multi-mode devices, 215802.11g, 802.11n, WPA/802.11i, WME, multi-bss, and 216add the extensible frameworks 217for cryptographic, authentication, and access control plugins. 218This manual page was written by 219.An Tom Rhodes Aq trhodes@FreeBSD.org . 220