1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>Frame format</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="The 802.11 subsystems &#8211; for kernel developers"><link rel="up" href="rx-tx.html" title="Chapter&#160;4.&#160;Receive and transmit processing"><link rel="prev" href="rx-tx.html" title="Chapter&#160;4.&#160;Receive and transmit processing"><link rel="next" href="bk02pt01ch04s03.html" title="Packet alignment"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Frame format</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="rx-tx.html">Prev</a>&#160;</td><th width="60%" align="center">Chapter&#160;4.&#160;Receive and transmit processing</th><td width="20%" align="right">&#160;<a accesskey="n" href="bk02pt01ch04s03.html">Next</a></td></tr></table><hr></div><div class="sect1"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp1113574860"></a>Frame format</h2></div></div></div><p>
2   </p><p>
3   As a general rule, when frames are passed between mac80211 and the driver,
4   they start with the IEEE 802.11 header and include the same octets that are
5   sent over the air except for the FCS which should be calculated by the
6   hardware.
7   </p><p>
8   There are, however, various exceptions to this rule for advanced features:
9   </p><p>
10   The first exception is for hardware encryption and decryption offload
11   where the IV/ICV may or may not be generated in hardware.
12   </p><p>
13   Secondly, when the hardware handles fragmentation, the frame handed to
14   the driver from mac80211 is the MSDU, not the MPDU.
15</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="rx-tx.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="rx-tx.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="bk02pt01ch04s03.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter&#160;4.&#160;Receive and transmit processing&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;Packet alignment</td></tr></table></div></body></html>
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