path: root/static/freebsd/man9/ieee80211.9 3.html

<table class="head">
  <tr>
    <td class="head-ltitle">IEEE80211(9)</td>
    <td class="head-vol">Kernel Developer's Manual</td>
    <td class="head-rtitle">IEEE80211(9)</td>
  </tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">IEEE80211</code> &#x2014; <span class="Nd">802.11
    network layer</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="In">#include
    &lt;<a class="In">net80211/ieee80211_var.h</a>&gt;</code></p>
<p class="Pp"><var class="Ft">void</var>
  <br/>
  <code class="Fn">ieee80211_ifattach</code>(<var class="Fa" style="white-space: nowrap;">struct
    ieee80211com *ic</var>);</p>
<p class="Pp"><var class="Ft">void</var>
  <br/>
  <code class="Fn">ieee80211_ifdetach</code>(<var class="Fa" style="white-space: nowrap;">struct
    ieee80211com *ic</var>);</p>
<p class="Pp"><var class="Ft">int</var>
  <br/>
  <code class="Fn">ieee80211_mhz2ieee</code>(<var class="Fa" style="white-space: nowrap;">u_int
    freq</var>, <var class="Fa" style="white-space: nowrap;">u_int
  flags</var>);</p>
<p class="Pp"><var class="Ft">int</var>
  <br/>
  <code class="Fn">ieee80211_chan2ieee</code>(<var class="Fa" style="white-space: nowrap;">struct
    ieee80211com *ic</var>, <var class="Fa" style="white-space: nowrap;">const
    struct ieee80211_channel *c</var>);</p>
<p class="Pp"><var class="Ft">u_int</var>
  <br/>
  <code class="Fn">ieee80211_ieee2mhz</code>(<var class="Fa" style="white-space: nowrap;">u_int
    chan</var>, <var class="Fa" style="white-space: nowrap;">u_int
  flags</var>);</p>
<p class="Pp"><var class="Ft">int</var>
  <br/>
  <code class="Fn">ieee80211_media_change</code>(<var class="Fa" style="white-space: nowrap;">struct
    ifnet *ifp</var>);</p>
<p class="Pp"><var class="Ft">void</var>
  <br/>
  <code class="Fn">ieee80211_media_status</code>(<var class="Fa" style="white-space: nowrap;">struct
    ifnet *ifp</var>, <var class="Fa" style="white-space: nowrap;">struct
    ifmediareq *imr</var>);</p>
<p class="Pp"><var class="Ft">int</var>
  <br/>
  <code class="Fn">ieee80211_setmode</code>(<var class="Fa" style="white-space: nowrap;">struct
    ieee80211com *ic</var>, <var class="Fa" style="white-space: nowrap;">enum
    ieee80211_phymode mode</var>);</p>
<p class="Pp"><var class="Ft">enum ieee80211_phymode</var>
  <br/>
  <code class="Fn">ieee80211_chan2mode</code>(<var class="Fa">const struct
    ieee80211_channel *chan</var>);</p>
<p class="Pp"><var class="Ft">int</var>
  <br/>
  <code class="Fn">ieee80211_rate2media</code>(<var class="Fa">struct
    ieee80211com *ic</var>, <var class="Fa">int rate</var>, <var class="Fa">enum
    ieee80211_phymode mode</var>);</p>
<p class="Pp"><var class="Ft">int</var>
  <br/>
  <code class="Fn">ieee80211_media2rate</code>(<var class="Fa" style="white-space: nowrap;">int
    mword</var>);</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">IEEE 802.11 device drivers are written to use the infrastructure
    provided by the <code class="Nm">IEEE80211</code> software layer. This
    software provides a support framework for drivers that includes ifnet
    cloning, state management, and a user management API by which applications
    interact with 802.11 devices. Most drivers depend on the
    <code class="Nm">IEEE80211</code> layer for protocol services but devices
    that off-load functionality may bypass the layer to connect directly to the
    device.</p>
<p class="Pp">A <code class="Nm">IEEE80211</code> device driver implements a
    virtual radio API that is exported to users through network interfaces (aka
    vaps) that are cloned from the underlying device. These interfaces have an
    operating mode (station, adhoc, hostap, wds, monitor, etc.) that is fixed
    for the lifetime of the interface. Devices that can support multiple
    concurrent interfaces allow multiple vaps to be cloned. This enables
    construction of interesting applications such as an AP vap and one or more
    WDS vaps or multiple AP vaps, each with a different security model. The
    <code class="Nm">IEEE80211</code> layer virtualizes most 802.11 state and
    coordinates vap state changes including scheduling multiple vaps. State that
    is not virtualized includes the current channel and WME/WMM parameters.
    Protocol processing is typically handled entirely in the
    <code class="Nm">IEEE80211</code> layer with drivers responsible purely for
    moving data between the host and device. Similarly,
    <code class="Nm">IEEE80211</code> handles most <a class="Xr">ioctl(2)</a>
    requests without entering the driver; instead drivers are notified of state
    changes that require their involvement.</p>
<p class="Pp">The virtual radio interface defined by the
    <code class="Nm">IEEE80211</code> layer means that drivers must be
    structured to follow specific rules. Drivers that support only a single
    interface at any time must still follow these rules.</p>
<p class="Pp">Most of these functions require that attachment to the stack is
    performed before calling.</p>
<p class="Pp" id="ieee80211_ifattach">The
    <a class="permalink" href="#ieee80211_ifattach"><code class="Fn">ieee80211_ifattach</code></a>()
    function attaches the wireless network interface <var class="Fa">ic</var> to
    the 802.11 network stack layer. This function must be called before using
    any of the <code class="Nm">IEEE80211</code> functions which need to store
    driver state across invocations.</p>
<p class="Pp" id="ieee80211_ifdetach">The
    <a class="permalink" href="#ieee80211_ifdetach"><code class="Fn">ieee80211_ifdetach</code></a>()
    function frees any <code class="Nm">IEEE80211</code> structures associated
    with the driver, and performs Ethernet and BPF detachment on behalf of the
    caller.</p>
<p class="Pp" id="ieee80211_mhz2ieee">The
    <a class="permalink" href="#ieee80211_mhz2ieee"><code class="Fn">ieee80211_mhz2ieee</code></a>()
    utility function converts the frequency <var class="Fa">freq</var>
    (specified in MHz) to an IEEE 802.11 channel number. The
    <var class="Fa">flags</var> argument is a hint which specifies whether the
    frequency is in the 2GHz ISM band
    (<var class="Vt">IEEE80211_CHAN_2GHZ</var>) or the 5GHz band
    (<var class="Vt">IEEE80211_CHAN_5GHZ</var>); appropriate clipping of the
    result is then performed.</p>
<p class="Pp" id="ieee80211_chan2ieee">The
    <a class="permalink" href="#ieee80211_chan2ieee"><code class="Fn">ieee80211_chan2ieee</code></a>()
    function converts the channel specified in <var class="Fa">*c</var> to an
    IEEE channel number for the driver <var class="Fa">ic</var>. 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
    <code class="Nm">IEEE80211</code> subsystem.</p>
<p class="Pp" id="ieee80211_ieee2mhz">The
    <a class="permalink" href="#ieee80211_ieee2mhz"><code class="Fn">ieee80211_ieee2mhz</code></a>()
    utility function converts the IEEE channel number <var class="Ft">chan</var>
    to a frequency (in MHz). The <var class="Fa">flags</var> argument is a hint
    which specifies whether the frequency is in the 2GHz ISM band
    (<var class="Vt">IEEE80211_CHAN_2GHZ</var>) or the 5GHz band
    (<var class="Vt">IEEE80211_CHAN_5GHZ</var>); appropriate clipping of the
    result is then performed.</p>
<p class="Pp" id="ieee80211_media_status">The
    <a class="permalink" href="#ieee80211_media_status"><code class="Fn">ieee80211_media_status</code></a>()
    and
    <a class="permalink" href="#ieee80211_media_change"><code class="Fn" id="ieee80211_media_change">ieee80211_media_change</code></a>()
    functions are device-independent handlers for <var class="Vt">ifmedia</var>
    commands and are not intended to be called directly.</p>
<p class="Pp" id="ieee80211_setmode">The
    <a class="permalink" href="#ieee80211_setmode"><code class="Fn">ieee80211_setmode</code></a>()
    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.</p>
<p class="Pp" id="ieee80211_chan2mode">The
    <a class="permalink" href="#ieee80211_chan2mode"><code class="Fn">ieee80211_chan2mode</code></a>()
    function returns the PHY mode required for use with the channel
    <var class="Fa">chan</var>. This is typically used when selecting a rate
    set, to be advertised in beacons, for example.</p>
<p class="Pp" id="ieee80211_rate2media">The
    <a class="permalink" href="#ieee80211_rate2media"><code class="Fn">ieee80211_rate2media</code></a>()
    function converts the bit rate <var class="Fa">rate</var> (measured in units
    of 0.5Mbps) to an <var class="Vt">ifmedia</var> sub-type, for the device
    <var class="Fa">ic</var> running in PHY mode <var class="Fa">mode</var>. The
    <a class="permalink" href="#ieee80211_media2rate"><code class="Fn" id="ieee80211_media2rate">ieee80211_media2rate</code></a>()
    performs the reverse of this conversion, returning the bit rate (in 0.5Mbps
    units) corresponding to an <var class="Vt">ifmedia</var> sub-type.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DATA_STRUCTURES"><a class="permalink" href="#DATA_STRUCTURES">DATA
  STRUCTURES</a></h1>
<p class="Pp">The virtual radio architecture splits state between a single
    per-device <var class="Vt">ieee80211com</var> structure and one or more
    <var class="Vt">ieee80211vap</var> structures. Drivers are expected to setup
    various shared state in these structures at device attach and during vap
    creation but otherwise should treat them as read-only. The
    <var class="Vt">ieee80211com</var> structure is allocated by the
    <code class="Nm">IEEE80211</code> layer as adjunct data to a device's
    <var class="Vt">ifnet</var>; it is accessed through the
    <var class="Vt">if_l2com</var> structure member. The
    <var class="Vt">ieee80211vap</var> structure is allocated by the driver in
    the &#x201C;vap create&#x201D; method and should be extended with any
    driver-private state. This technique of giving the driver control to
    allocate data structures is used for other <code class="Nm">IEEE80211</code>
    data structures and should be exploited to maintain driver-private state
    together with public <code class="Nm">IEEE80211</code> state.</p>
<p class="Pp">The other main data structures are the station, or node, table
    that tracks peers in the local BSS, and the channel table that defines the
    current set of available radio channels. Both tables are bound to the
    <var class="Vt">ieee80211com</var> structure and shared by all vaps.
    Long-lasting references to a node are counted to guard against premature
    reclamation. In particular every packet sent/received holds a node reference
    (either explicitly for transmit or implicitly on receive).</p>
<p class="Pp">The <var class="Vt">ieee80211com</var> and
    <var class="Vt">ieee80211vap</var> structures also hold a collection of
    method pointers that drivers fill-in and/or override to take control of
    certain operations. These methods are the primary way drivers are bound to
    the <code class="Nm">IEEE80211</code> layer and are described below.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DRIVER_ATTACH/DETACH"><a class="permalink" href="#DRIVER_ATTACH/DETACH">DRIVER
  ATTACH/DETACH</a></h1>
<p class="Pp">Drivers attach to the <code class="Nm">IEEE80211</code> layer with
    the
    <a class="permalink" href="#ieee80211_ifattach~2"><code class="Fn" id="ieee80211_ifattach~2">ieee80211_ifattach</code></a>()
    function. The driver is expected to allocate and setup any device-private
    data structures before passing control. The
    <var class="Vt">ieee80211com</var> structure must be pre-initialized with
    state required to setup the <code class="Nm">IEEE80211</code> layer:</p>
<dl class="Bl-tag">
  <dt id="ic_ifp"><a class="permalink" href="#ic_ifp"><code class="Dv">ic_ifp</code></a></dt>
  <dd>Backpointer to the physical device's ifnet.</dd>
  <dt id="ic_caps"><a class="permalink" href="#ic_caps"><code class="Dv">ic_caps</code></a></dt>
  <dd>Device/driver capabilities; see below for a complete description.</dd>
  <dt id="ic_channels"><a class="permalink" href="#ic_channels"><code class="Dv">ic_channels</code></a></dt>
  <dd>Table of channels the device is capable of operating on. This is initially
      provided by the driver but may be changed through calls that change the
      regulatory state.</dd>
  <dt id="ic_nchan"><a class="permalink" href="#ic_nchan"><code class="Dv">ic_nchan</code></a></dt>
  <dd>Number of entries in <code class="Dv">ic_channels</code>.</dd>
</dl>
<p class="Pp" id="ieee80211_ifattach~3">On return from
    <a class="permalink" href="#ieee80211_ifattach~3"><code class="Fn">ieee80211_ifattach</code></a>()
    the driver is expected to override default callback functions in the
    <var class="Vt">ieee80211com</var> structure to register it's private
    routines. Methods marked with a &#x201C;*&#x201D; must be provided by the
    driver.</p>
<dl class="Bl-tag">
  <dt id="ic_vap_create*"><a class="permalink" href="#ic_vap_create*"><code class="Dv">ic_vap_create*</code></a></dt>
  <dd>Create a vap instance of the specified type (operating mode). Any fixed
      BSSID and/or MAC address is provided. Drivers that support multi-bssid
      operation may honor the requested BSSID or assign their own.</dd>
  <dt id="ic_vap_delete*"><a class="permalink" href="#ic_vap_delete*"><code class="Dv">ic_vap_delete*</code></a></dt>
  <dd>Destroy a vap instance created with
    <code class="Dv">ic_vap_create</code>.</dd>
  <dt id="ic_getradiocaps"><a class="permalink" href="#ic_getradiocaps"><code class="Dv">ic_getradiocaps</code></a></dt>
  <dd>Return the list of calibrated channels for the radio. The default method
      returns the current list of channels (space permitting).</dd>
  <dt id="ic_setregdomain"><a class="permalink" href="#ic_setregdomain"><code class="Dv">ic_setregdomain</code></a></dt>
  <dd>Process a request to change regulatory state. The routine may reject a
      request or constrain changes (e.g. reduce transmit power caps). The
      default method accepts all proposed changes.</dd>
  <dt id="ic_send_mgmt"><a class="permalink" href="#ic_send_mgmt"><code class="Dv">ic_send_mgmt</code></a></dt>
  <dd>Send an 802.11 management frame. The default method fabricates the frame
      using <code class="Nm">IEEE80211</code> state and passes it to the driver
      through the <code class="Dv">ic_raw_xmit</code> method.</dd>
  <dt id="ic_raw_xmit"><a class="permalink" href="#ic_raw_xmit"><code class="Dv">ic_raw_xmit</code></a></dt>
  <dd>Transmit a raw 802.11 frame. The default method drops the frame and
      generates a message on the console.</dd>
  <dt id="ic_updateslot"><a class="permalink" href="#ic_updateslot"><code class="Dv">ic_updateslot</code></a></dt>
  <dd>Update hardware state after an 802.11 IFS slot time change. There is no
      default method; the pointer may be NULL in which case it will not be
    used.</dd>
  <dt id="ic_update_mcast"><a class="permalink" href="#ic_update_mcast"><code class="Dv">ic_update_mcast</code></a></dt>
  <dd>Update hardware for a change in the multicast packet filter. The default
      method prints a console message.</dd>
  <dt id="ic_update_promisc"><a class="permalink" href="#ic_update_promisc"><code class="Dv">ic_update_promisc</code></a></dt>
  <dd>Update hardware for a change in the promiscuous mode setting. The default
      method prints a console message.</dd>
  <dt id="ic_newassoc"><a class="permalink" href="#ic_newassoc"><code class="Dv">ic_newassoc</code></a></dt>
  <dd>Update driver/device state for association to a new AP (in station mode)
      or when a new station associates (e.g. in AP mode). There is no default
      method; the pointer may be NULL in which case it will not be used.</dd>
  <dt id="ic_node_alloc"><a class="permalink" href="#ic_node_alloc"><code class="Dv">ic_node_alloc</code></a></dt>
  <dd>Allocate and initialize a <var class="Vt">ieee80211_node</var> structure.
      This method cannot sleep. The default method allocates zero'd memory using
      <a class="Xr">malloc(9)</a>. Drivers should override this method to
      allocate extended storage for their own needs. Memory allocated by the
      driver must be tagged with <code class="Dv">M_80211_NODE</code> to balance
      the memory allocation statistics.</dd>
  <dt id="ic_node_free"><a class="permalink" href="#ic_node_free"><code class="Dv">ic_node_free</code></a></dt>
  <dd>Reclaim storage of a node allocated by
      <code class="Dv">ic_node_alloc</code>. Drivers are expected to
      <a class="permalink" href="#interpose"><i class="Em" id="interpose">interpose</i></a>
      their own method to cleanup private state but must call through this
      method to allow <code class="Nm">IEEE80211</code> to reclaim it's private
      state.</dd>
  <dt id="ic_node_cleanup"><a class="permalink" href="#ic_node_cleanup"><code class="Dv">ic_node_cleanup</code></a></dt>
  <dd>Cleanup state in a <var class="Vt">ieee80211_node</var> created by
      <code class="Dv">ic_node_alloc</code>. This operation is distinguished
      from <code class="Dv">ic_node_free</code> in that it may be called long
      before the node is actually reclaimed to cleanup adjunct state. This can
      happen, for example, when a node must not be reclaimed due to references
      held by packets in the transmit queue. Drivers typically interpose
      <code class="Dv">ic_node_cleanup</code> instead of
      <code class="Dv">ic_node_free</code>.</dd>
  <dt id="ic_node_age"><a class="permalink" href="#ic_node_age"><code class="Dv">ic_node_age</code></a></dt>
  <dd>Age, and potentially reclaim, resources associated with a node. The
      default method ages frames on the power-save queue (in AP mode) and
      pending frames in the receive reorder queues (for stations using
    A-MPDU).</dd>
  <dt id="ic_node_drain"><a class="permalink" href="#ic_node_drain"><code class="Dv">ic_node_drain</code></a></dt>
  <dd>Reclaim all optional resources associated with a node. This call is used
      to free up resources when they are in short supply.</dd>
  <dt id="ic_node_getrssi"><a class="permalink" href="#ic_node_getrssi"><code class="Dv">ic_node_getrssi</code></a></dt>
  <dd>Return the Receive Signal Strength Indication (RSSI) in .5 dBm units for
      the specified node. This interface returns a subset of the information
      returned by <code class="Dv">ic_node_getsignal</code>. The default method
      calculates a filtered average over the last ten samples passed in to
      <a class="Xr">ieee80211_input(9)</a> or
      <a class="Xr">ieee80211_input_all(9)</a>.</dd>
  <dt id="ic_node_getsignal"><a class="permalink" href="#ic_node_getsignal"><code class="Dv">ic_node_getsignal</code></a></dt>
  <dd>Return the RSSI and noise floor (in .5 dBm units) for a station. The
      default method calculates RSSI as described above; the noise floor
      returned is the last value supplied to
      <a class="Xr">ieee80211_input(9)</a> or
      <a class="Xr">ieee80211_input_all(9)</a>.</dd>
  <dt id="ic_node_getmimoinfo"><a class="permalink" href="#ic_node_getmimoinfo"><code class="Dv">ic_node_getmimoinfo</code></a></dt>
  <dd>Return MIMO radio state for a station in support of the
      <code class="Dv">IEEE80211_IOC_STA_INFO</code> ioctl request. The default
      method returns nothing.</dd>
  <dt id="ic_scan_start*"><a class="permalink" href="#ic_scan_start*"><code class="Dv">ic_scan_start*</code></a></dt>
  <dd>Prepare driver/hardware state for scanning. This callback is done in a
      sleepable context.</dd>
  <dt id="ic_scan_end*"><a class="permalink" href="#ic_scan_end*"><code class="Dv">ic_scan_end*</code></a></dt>
  <dd>Restore driver/hardware state after scanning completes. This callback is
      done in a sleepable context.</dd>
  <dt id="ic_set_channel*"><a class="permalink" href="#ic_set_channel*"><code class="Dv">ic_set_channel*</code></a></dt>
  <dd>Set the current radio channel using <var class="Vt">ic_curchan</var>. This
      callback is done in a sleepable context.</dd>
  <dt id="ic_scan_curchan"><a class="permalink" href="#ic_scan_curchan"><code class="Dv">ic_scan_curchan</code></a></dt>
  <dd>Start scanning on a channel. This method is called immediately after each
      channel change and must initiate the work to scan a channel and schedule a
      timer to advance to the next channel in the scan list. This callback is
      done in a sleepable context. The default method handles active scan work
      (e.g. sending ProbeRequest frames), and schedules a call to
      <a class="Xr">ieee80211_scan_next(9)</a> according to the maximum dwell
      time for the channel. Drivers that off-load scan work to firmware
      typically use this method to trigger per-channel scan activity.</dd>
  <dt id="ic_scan_mindwell"><a class="permalink" href="#ic_scan_mindwell"><code class="Dv">ic_scan_mindwell</code></a></dt>
  <dd>Handle reaching the minimum dwell time on a channel when scanning. This
      event is triggered when one or more stations have been found on a channel
      and the minimum dwell time has been reached. This callback is done in a
      sleepable context. The default method signals the scan machinery to
      advance to the next channel as soon as possible. Drivers can use this
      method to preempt further work (e.g. if scanning is handled by firmware)
      or ignore the request to force maximum dwell time on a channel.</dd>
  <dt id="ic_recv_action"><a class="permalink" href="#ic_recv_action"><code class="Dv">ic_recv_action</code></a></dt>
  <dd>Process a received Action frame. The default method points to
      <a class="Xr">ieee80211_recv_action(9)</a> which provides a mechanism for
      setting up handlers for each Action frame class.</dd>
  <dt id="ic_send_action"><a class="permalink" href="#ic_send_action"><code class="Dv">ic_send_action</code></a></dt>
  <dd>Transmit an Action frame. The default method points to
      <a class="Xr">ieee80211_send_action(9)</a> which provides a mechanism for
      setting up handlers for each Action frame class.</dd>
  <dt id="ic_ampdu_enable"><a class="permalink" href="#ic_ampdu_enable"><code class="Dv">ic_ampdu_enable</code></a></dt>
  <dd>Check if transmit A-MPDU should be enabled for the specified station and
      AC. The default method checks a per-AC traffic rate against a per-vap
      threshold to decide if A-MPDU should be enabled. This method also
      rate-limits ADDBA requests so that requests are not made too frequently
      when a receiver has limited resources.</dd>
  <dt id="ic_addba_request"><a class="permalink" href="#ic_addba_request"><code class="Dv">ic_addba_request</code></a></dt>
  <dd>Request A-MPDU transmit aggregation. The default method sets up local
      state and issues an ADDBA Request Action frame. Drivers may interpose this
      method if they need to setup private state for handling transmit
    A-MPDU.</dd>
  <dt id="ic_addb_response"><a class="permalink" href="#ic_addb_response"><code class="Dv">ic_addb_response</code></a></dt>
  <dd>Process a received ADDBA Response Action frame and setup resources as
      needed for doing transmit A-MPDU.</dd>
  <dt id="ic_addb_stop"><a class="permalink" href="#ic_addb_stop"><code class="Dv">ic_addb_stop</code></a></dt>
  <dd>Shutdown an A-MPDU transmit stream for the specified station and AC. The
      default method reclaims local state after sending a DelBA Action
    frame.</dd>
  <dt id="ic_bar_response"><a class="permalink" href="#ic_bar_response"><code class="Dv">ic_bar_response</code></a></dt>
  <dd>Process a response to a transmitted BAR control frame.</dd>
  <dt id="ic_ampdu_rx_start"><a class="permalink" href="#ic_ampdu_rx_start"><code class="Dv">ic_ampdu_rx_start</code></a></dt>
  <dd>Prepare to receive A-MPDU data from the specified station for the
    TID.</dd>
  <dt id="ic_ampdu_rx_stop"><a class="permalink" href="#ic_ampdu_rx_stop"><code class="Dv">ic_ampdu_rx_stop</code></a></dt>
  <dd>Terminate receipt of A-MPDU data from the specified station for the
    TID.</dd>
</dl>
<p class="Pp">Once the <code class="Nm">IEEE80211</code> layer is attached to a
    driver there are two more steps typically done to complete the work:</p>
<ol class="Bl-enum">
  <li>Setup &#x201C;radiotap support&#x201D; for capturing raw 802.11 packets
      that pass through the device. This is done with a call to
      <a class="Xr">ieee80211_radiotap_attach(9)</a>.</li>
  <li>Do any final device setup like enabling interrupts.</li>
</ol>
<p class="Pp" id="ieee80211_ifdetach~2">State is torn down and reclaimed with a
    call to
    <a class="permalink" href="#ieee80211_ifdetach~2"><code class="Fn">ieee80211_ifdetach</code></a>().
    Note this call may result in multiple callbacks into the driver so it should
    be done before any critical driver state is reclaimed. On return from
    <code class="Fn">ieee80211_ifdetach</code>() all associated vaps and ifnet
    structures are reclaimed or inaccessible to user applications so it is safe
    to teardown driver state without worry about being re-entered. The driver is
    responsible for calling <a class="Xr">if_free(9)</a> on the ifnet it
    allocated for the physical device.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DRIVER_CAPABILITIES"><a class="permalink" href="#DRIVER_CAPABILITIES">DRIVER
  CAPABILITIES</a></h1>
<p class="Pp">Driver/device capabilities are specified using several sets of
    flags in the <var class="Vt">ieee80211com</var> structure. General
    capabilities are specified by <var class="Vt">ic_caps</var>. Hardware
    cryptographic capabilities are specified by
    <var class="Vt">ic_cryptocaps</var>. Software cryptographic capabilities are
    specified by <var class="Vt">ic_sw_cryptocaps</var>. 802.11n capabilities,
    if any, are specified by <var class="Vt">ic_htcaps</var>. The
    <code class="Nm">IEEE80211</code> layer propagates a subset of these
    capabilities to each vap through the equivalent fields:
    <var class="Vt">iv_caps</var>, <var class="Vt">iv_cryptocaps</var>, and
    <var class="Vt">iv_htcaps</var>. The following general capabilities are
    defined:</p>
<dl class="Bl-tag">
  <dt id="IEEE80211_C_STA"><a class="permalink" href="#IEEE80211_C_STA"><code class="Dv">IEEE80211_C_STA</code></a></dt>
  <dd>Device is capable of operating in station (aka Infrastructure) mode.</dd>
  <dt id="IEEE80211_C_8023ENCAP"><a class="permalink" href="#IEEE80211_C_8023ENCAP"><code class="Dv">IEEE80211_C_8023ENCAP</code></a></dt>
  <dd>Device requires 802.3-encapsulated frames be passed for transmit. By
      default <code class="Nm">IEEE80211</code> will encapsulate all outbound
      frames as 802.11 frames (without a PLCP header).</dd>
  <dt id="IEEE80211_C_FF"><a class="permalink" href="#IEEE80211_C_FF"><code class="Dv">IEEE80211_C_FF</code></a></dt>
  <dd>Device supports Atheros Fast-Frames.</dd>
  <dt id="IEEE80211_C_TURBOP"><a class="permalink" href="#IEEE80211_C_TURBOP"><code class="Dv">IEEE80211_C_TURBOP</code></a></dt>
  <dd>Device supports Atheros Dynamic Turbo mode.</dd>
  <dt id="IEEE80211_C_IBSS"><a class="permalink" href="#IEEE80211_C_IBSS"><code class="Dv">IEEE80211_C_IBSS</code></a></dt>
  <dd>Device is capable of operating in adhoc/IBSS mode.</dd>
  <dt id="IEEE80211_C_PMGT"><a class="permalink" href="#IEEE80211_C_PMGT"><code class="Dv">IEEE80211_C_PMGT</code></a></dt>
  <dd>Device supports dynamic power-management (aka power save) in station
    mode.</dd>
  <dt id="IEEE80211_C_HOSTAP"><a class="permalink" href="#IEEE80211_C_HOSTAP"><code class="Dv">IEEE80211_C_HOSTAP</code></a></dt>
  <dd>Device is capable of operating as an Access Point in Infrastructure
    mode.</dd>
  <dt id="IEEE80211_C_AHDEMO"><a class="permalink" href="#IEEE80211_C_AHDEMO"><code class="Dv">IEEE80211_C_AHDEMO</code></a></dt>
  <dd>Device is capable of operating in Adhoc Demo mode. In this mode the device
      is used purely to send/receive raw 802.11 frames.</dd>
  <dt id="IEEE80211_C_SWRETRY"><a class="permalink" href="#IEEE80211_C_SWRETRY"><code class="Dv">IEEE80211_C_SWRETRY</code></a></dt>
  <dd>Device supports software retry of transmitted frames.</dd>
  <dt id="IEEE80211_C_TXPMGT"><a class="permalink" href="#IEEE80211_C_TXPMGT"><code class="Dv">IEEE80211_C_TXPMGT</code></a></dt>
  <dd>Device support dynamic transmit power changes on transmitted frames; also
      known as Transmit Power Control (TPC).</dd>
  <dt id="IEEE80211_C_SHSLOT"><a class="permalink" href="#IEEE80211_C_SHSLOT"><code class="Dv">IEEE80211_C_SHSLOT</code></a></dt>
  <dd>Device supports short slot time operation (for 802.11g).</dd>
  <dt id="IEEE80211_C_SHPREAMBLE"><a class="permalink" href="#IEEE80211_C_SHPREAMBLE"><code class="Dv">IEEE80211_C_SHPREAMBLE</code></a></dt>
  <dd>Device supports short preamble operation (for 802.11g).</dd>
  <dt id="IEEE80211_C_MONITOR"><a class="permalink" href="#IEEE80211_C_MONITOR"><code class="Dv">IEEE80211_C_MONITOR</code></a></dt>
  <dd>Device is capable of operating in monitor mode.</dd>
  <dt id="IEEE80211_C_DFS"><a class="permalink" href="#IEEE80211_C_DFS"><code class="Dv">IEEE80211_C_DFS</code></a></dt>
  <dd>Device supports radar detection and/or DFS. DFS protocol support can be
      handled by <code class="Nm">IEEE80211</code> but the device must be
      capable of detecting radar events.</dd>
  <dt id="IEEE80211_C_MBSS"><a class="permalink" href="#IEEE80211_C_MBSS"><code class="Dv">IEEE80211_C_MBSS</code></a></dt>
  <dd>Device is capable of operating in MeshBSS (MBSS) mode (as defined by
      802.11s Draft 3.0).</dd>
  <dt id="IEEE80211_C_WPA1"><a class="permalink" href="#IEEE80211_C_WPA1"><code class="Dv">IEEE80211_C_WPA1</code></a></dt>
  <dd>Device supports WPA1 operation.</dd>
  <dt id="IEEE80211_C_WPA2"><a class="permalink" href="#IEEE80211_C_WPA2"><code class="Dv">IEEE80211_C_WPA2</code></a></dt>
  <dd>Device supports WPA2/802.11i operation.</dd>
  <dt id="IEEE80211_C_BURST"><a class="permalink" href="#IEEE80211_C_BURST"><code class="Dv">IEEE80211_C_BURST</code></a></dt>
  <dd>Device supports frame bursting.</dd>
  <dt id="IEEE80211_C_WME"><a class="permalink" href="#IEEE80211_C_WME"><code class="Dv">IEEE80211_C_WME</code></a></dt>
  <dd>Device supports WME/WMM operation (at the moment this is mostly support
      for sending and receiving QoS frames with EDCF).</dd>
  <dt id="IEEE80211_C_WDS"><a class="permalink" href="#IEEE80211_C_WDS"><code class="Dv">IEEE80211_C_WDS</code></a></dt>
  <dd>Device supports transmit/receive of 4-address frames.</dd>
  <dt id="IEEE80211_C_BGSCAN"><a class="permalink" href="#IEEE80211_C_BGSCAN"><code class="Dv">IEEE80211_C_BGSCAN</code></a></dt>
  <dd>Device supports background scanning.</dd>
  <dt id="IEEE80211_C_TXFRAG"><a class="permalink" href="#IEEE80211_C_TXFRAG"><code class="Dv">IEEE80211_C_TXFRAG</code></a></dt>
  <dd>Device supports transmit of fragmented 802.11 frames.</dd>
  <dt id="IEEE80211_C_TDMA"><a class="permalink" href="#IEEE80211_C_TDMA"><code class="Dv">IEEE80211_C_TDMA</code></a></dt>
  <dd>Device is capable of operating in TDMA mode.</dd>
</dl>
<p class="Pp">The follow general crypto capabilities are defined. In general
    <code class="Nm">IEEE80211</code> will fall-back to software support when a
    device is not capable of hardware acceleration of a cipher. This can be done
    on a per-key basis. <code class="Nm">IEEE80211</code> can also handle
    software <code class="Dv">Michael</code> calculation combined with hardware
    <code class="Dv">AES</code> acceleration.</p>
<dl class="Bl-tag">
  <dt id="IEEE80211_CRYPTO_WEP"><a class="permalink" href="#IEEE80211_CRYPTO_WEP"><code class="Dv">IEEE80211_CRYPTO_WEP</code></a></dt>
  <dd>Device supports hardware WEP cipher.</dd>
  <dt id="IEEE80211_CRYPTO_TKIP"><a class="permalink" href="#IEEE80211_CRYPTO_TKIP"><code class="Dv">IEEE80211_CRYPTO_TKIP</code></a></dt>
  <dd>Device supports hardware TKIP cipher.</dd>
  <dt id="IEEE80211_CRYPTO_AES_OCB"><a class="permalink" href="#IEEE80211_CRYPTO_AES_OCB"><code class="Dv">IEEE80211_CRYPTO_AES_OCB</code></a></dt>
  <dd>Device supports hardware AES-OCB cipher.</dd>
  <dt id="IEEE80211_CRYPTO_AES_CCM"><a class="permalink" href="#IEEE80211_CRYPTO_AES_CCM"><code class="Dv">IEEE80211_CRYPTO_AES_CCM</code></a></dt>
  <dd>Device supports hardware AES-CCM cipher.</dd>
  <dt id="IEEE80211_CRYPTO_TKIPMIC"><a class="permalink" href="#IEEE80211_CRYPTO_TKIPMIC"><code class="Dv">IEEE80211_CRYPTO_TKIPMIC</code></a></dt>
  <dd>Device supports hardware Michael for use with TKIP.</dd>
  <dt id="IEEE80211_CRYPTO_CKIP"><a class="permalink" href="#IEEE80211_CRYPTO_CKIP"><code class="Dv">IEEE80211_CRYPTO_CKIP</code></a></dt>
  <dd>Devices supports hardware CKIP cipher.</dd>
</dl>
<p class="Pp">The follow general 802.11n capabilities are defined. The first
    capabilities are defined exactly as they appear in the 802.11n
    specification. Capabilities beginning with IEEE80211_HTC_AMPDU are used
    solely by the <code class="Nm">IEEE80211</code> layer.</p>
<dl class="Bl-tag">
  <dt id="IEEE80211_HTCAP_CHWIDTH40"><a class="permalink" href="#IEEE80211_HTCAP_CHWIDTH40"><code class="Dv">IEEE80211_HTCAP_CHWIDTH40</code></a></dt>
  <dd>Device supports 20/40 channel width operation.</dd>
  <dt id="IEEE80211_HTCAP_SMPS_DYNAMIC"><a class="permalink" href="#IEEE80211_HTCAP_SMPS_DYNAMIC"><code class="Dv">IEEE80211_HTCAP_SMPS_DYNAMIC</code></a></dt>
  <dd>Device supports dynamic SM power save operation.</dd>
  <dt id="IEEE80211_HTCAP_SMPS_ENA"><a class="permalink" href="#IEEE80211_HTCAP_SMPS_ENA"><code class="Dv">IEEE80211_HTCAP_SMPS_ENA</code></a></dt>
  <dd>Device supports static SM power save operation.</dd>
  <dt id="IEEE80211_HTCAP_GREENFIELD"><a class="permalink" href="#IEEE80211_HTCAP_GREENFIELD"><code class="Dv">IEEE80211_HTCAP_GREENFIELD</code></a></dt>
  <dd>Device supports Greenfield preamble.</dd>
  <dt id="IEEE80211_HTCAP_SHORTGI20"><a class="permalink" href="#IEEE80211_HTCAP_SHORTGI20"><code class="Dv">IEEE80211_HTCAP_SHORTGI20</code></a></dt>
  <dd>Device supports Short Guard Interval on 20MHz channels.</dd>
  <dt id="IEEE80211_HTCAP_SHORTGI40"><a class="permalink" href="#IEEE80211_HTCAP_SHORTGI40"><code class="Dv">IEEE80211_HTCAP_SHORTGI40</code></a></dt>
  <dd>Device supports Short Guard Interval on 40MHz channels.</dd>
  <dt id="IEEE80211_HTCAP_TXSTBC"><a class="permalink" href="#IEEE80211_HTCAP_TXSTBC"><code class="Dv">IEEE80211_HTCAP_TXSTBC</code></a></dt>
  <dd>Device supports Space Time Block Convolution (STBC) for transmit.</dd>
  <dt id="IEEE80211_HTCAP_RXSTBC_1STREAM"><a class="permalink" href="#IEEE80211_HTCAP_RXSTBC_1STREAM"><code class="Dv">IEEE80211_HTCAP_RXSTBC_1STREAM</code></a></dt>
  <dd>Device supports 1 spatial stream for STBC receive.</dd>
  <dt id="IEEE80211_HTCAP_RXSTBC_2STREAM"><a class="permalink" href="#IEEE80211_HTCAP_RXSTBC_2STREAM"><code class="Dv">IEEE80211_HTCAP_RXSTBC_2STREAM</code></a></dt>
  <dd>Device supports 1-2 spatial streams for STBC receive.</dd>
  <dt id="IEEE80211_HTCAP_RXSTBC_3STREAM"><a class="permalink" href="#IEEE80211_HTCAP_RXSTBC_3STREAM"><code class="Dv">IEEE80211_HTCAP_RXSTBC_3STREAM</code></a></dt>
  <dd>Device supports 1-3 spatial streams for STBC receive.</dd>
  <dt id="IEEE80211_HTCAP_MAXAMSDU_7935"><a class="permalink" href="#IEEE80211_HTCAP_MAXAMSDU_7935"><code class="Dv">IEEE80211_HTCAP_MAXAMSDU_7935</code></a></dt>
  <dd>Device supports A-MSDU frames up to 7935 octets.</dd>
  <dt id="IEEE80211_HTCAP_MAXAMSDU_3839"><a class="permalink" href="#IEEE80211_HTCAP_MAXAMSDU_3839"><code class="Dv">IEEE80211_HTCAP_MAXAMSDU_3839</code></a></dt>
  <dd>Device supports A-MSDU frames up to 3839 octets.</dd>
  <dt id="IEEE80211_HTCAP_DSSSCCK40"><a class="permalink" href="#IEEE80211_HTCAP_DSSSCCK40"><code class="Dv">IEEE80211_HTCAP_DSSSCCK40</code></a></dt>
  <dd>Device supports use of DSSS/CCK on 40MHz channels.</dd>
  <dt id="IEEE80211_HTCAP_PSMP"><a class="permalink" href="#IEEE80211_HTCAP_PSMP"><code class="Dv">IEEE80211_HTCAP_PSMP</code></a></dt>
  <dd>Device supports PSMP.</dd>
  <dt id="IEEE80211_HTCAP_40INTOLERANT"><a class="permalink" href="#IEEE80211_HTCAP_40INTOLERANT"><code class="Dv">IEEE80211_HTCAP_40INTOLERANT</code></a></dt>
  <dd>Device is intolerant of 40MHz wide channel use.</dd>
  <dt id="IEEE80211_HTCAP_LSIGTXOPPROT"><a class="permalink" href="#IEEE80211_HTCAP_LSIGTXOPPROT"><code class="Dv">IEEE80211_HTCAP_LSIGTXOPPROT</code></a></dt>
  <dd>Device supports L-SIG TXOP protection.</dd>
  <dt id="IEEE80211_HTC_AMPDU"><a class="permalink" href="#IEEE80211_HTC_AMPDU"><code class="Dv">IEEE80211_HTC_AMPDU</code></a></dt>
  <dd>Device supports A-MPDU aggregation. Note that any 802.11n compliant device
      must support A-MPDU receive so this implicitly means support for
      <i class="Em">transmit</i> of A-MPDU frames.</dd>
  <dt id="IEEE80211_HTC_AMSDU"><a class="permalink" href="#IEEE80211_HTC_AMSDU"><code class="Dv">IEEE80211_HTC_AMSDU</code></a></dt>
  <dd>Device supports A-MSDU aggregation. Note that any 802.11n compliant device
      must support A-MSDU receive so this implicitly means support for
      <i class="Em">transmit</i> of A-MSDU frames.</dd>
  <dt id="IEEE80211_HTC_HT"><a class="permalink" href="#IEEE80211_HTC_HT"><code class="Dv">IEEE80211_HTC_HT</code></a></dt>
  <dd>Device supports High Throughput (HT) operation. This capability must be
      set to enable 802.11n functionality in
    <code class="Nm">IEEE80211</code>.</dd>
  <dt id="IEEE80211_HTC_SMPS"><a class="permalink" href="#IEEE80211_HTC_SMPS"><code class="Dv">IEEE80211_HTC_SMPS</code></a></dt>
  <dd>Device supports MIMO Power Save operation.</dd>
  <dt id="IEEE80211_HTC_RIFS"><a class="permalink" href="#IEEE80211_HTC_RIFS"><code class="Dv">IEEE80211_HTC_RIFS</code></a></dt>
  <dd>Device supports Reduced Inter Frame Spacing (RIFS).</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
  ALSO</a></h1>
<p class="Pp"><a class="Xr">ioctl(2)</a>, <a class="Xr">ieee80211_amrr(9)</a>,
    <a class="Xr">ieee80211_beacon(9)</a>, <a class="Xr">ieee80211_bmiss(9)</a>,
    <a class="Xr">ieee80211_crypto(9)</a>, <a class="Xr">ieee80211_ddb(9)</a>,
    <a class="Xr">ieee80211_input(9)</a>, <a class="Xr">ieee80211_node(9)</a>,
    <a class="Xr">ieee80211_output(9)</a>, <a class="Xr">ieee80211_proto(9)</a>,
    <a class="Xr">ieee80211_radiotap(9)</a>,
    <a class="Xr">ieee80211_regdomain(9)</a>,
    <a class="Xr">ieee80211_scan(9)</a>, <a class="Xr">ieee80211_vap(9)</a>,
    <a class="Xr">ifnet(9)</a>, <a class="Xr">malloc(9)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <code class="Nm">IEEE80211</code> series of functions first
    appeared in <span class="Ux">NetBSD 1.5</span>, and were later ported to
    <span class="Ux">FreeBSD 4.6</span>. This man page was updated with the
    information from <span class="Ux">NetBSD</span>
    <code class="Nm">IEEE80211</code> man page.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">The original <span class="Ux">NetBSD</span>
    <code class="Nm">IEEE80211</code> man page was written by
    <span class="An">Bruce M. Simpson</span>
    &lt;<a class="Mt" href="mailto:bms@FreeBSD.org">bms@FreeBSD.org</a>&gt; and
    <span class="An">Darron Broad</span>
    &lt;<a class="Mt" href="mailto:darron@kewl.org">darron@kewl.org</a>&gt;.</p>
</section>
</div>
<table class="foot">
  <tr>
    <td class="foot-date">April 24, 2024</td>
    <td class="foot-os">FreeBSD 15.0</td>
  </tr>
</table>