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<h1>uip/uip-split.h</h1><a href="a00134.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/*</span>
<a name="l00002"></a>00002 <span class="comment"> * Copyright (c) 2004, Swedish Institute of Computer Science.</span>
<a name="l00003"></a>00003 <span class="comment"> * All rights reserved.</span>
<a name="l00004"></a>00004 <span class="comment"> *</span>
<a name="l00005"></a>00005 <span class="comment"> * Redistribution and use in source and binary forms, with or without</span>
<a name="l00006"></a>00006 <span class="comment"> * modification, are permitted provided that the following conditions</span>
<a name="l00007"></a>00007 <span class="comment"> * are met:</span>
<a name="l00008"></a>00008 <span class="comment"> * 1. Redistributions of source code must retain the above copyright</span>
<a name="l00009"></a>00009 <span class="comment"> * notice, this list of conditions and the following disclaimer.</span>
<a name="l00010"></a>00010 <span class="comment"> * 2. Redistributions in binary form must reproduce the above copyright</span>
<a name="l00011"></a>00011 <span class="comment"> * notice, this list of conditions and the following disclaimer in the</span>
<a name="l00012"></a>00012 <span class="comment"> * documentation and/or other materials provided with the distribution.</span>
<a name="l00013"></a>00013 <span class="comment"> * 3. Neither the name of the Institute nor the names of its contributors</span>
<a name="l00014"></a>00014 <span class="comment"> * may be used to endorse or promote products derived from this software</span>
<a name="l00015"></a>00015 <span class="comment"> * without specific prior written permission.</span>
<a name="l00016"></a>00016 <span class="comment"> *</span>
<a name="l00017"></a>00017 <span class="comment"> * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND</span>
<a name="l00018"></a>00018 <span class="comment"> * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE</span>
<a name="l00019"></a>00019 <span class="comment"> * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE</span>
<a name="l00020"></a>00020 <span class="comment"> * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE</span>
<a name="l00021"></a>00021 <span class="comment"> * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL</span>
<a name="l00022"></a>00022 <span class="comment"> * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS</span>
<a name="l00023"></a>00023 <span class="comment"> * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)</span>
<a name="l00024"></a>00024 <span class="comment"> * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT</span>
<a name="l00025"></a>00025 <span class="comment"> * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY</span>
<a name="l00026"></a>00026 <span class="comment"> * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF</span>
<a name="l00027"></a>00027 <span class="comment"> * SUCH DAMAGE.</span>
<a name="l00028"></a>00028 <span class="comment"> *</span>
<a name="l00029"></a>00029 <span class="comment"> * This file is part of the uIP TCP/IP stack</span>
<a name="l00030"></a>00030 <span class="comment"> *</span>
<a name="l00031"></a>00031 <span class="comment"> * Author: Adam Dunkels &lt;adam@sics.se&gt;</span>
<a name="l00032"></a>00032 <span class="comment"> *</span>
<a name="l00033"></a>00033 <span class="comment"> * $Id: uip-split.h,v 1.2 2006/06/12 08:00:30 adam Exp $</span>
<a name="l00034"></a>00034 <span class="comment"> */</span><span class="comment"></span>
<a name="l00035"></a>00035 <span class="comment">/**</span>
<a name="l00036"></a>00036 <span class="comment"> * \addtogroup uip</span>
<a name="l00037"></a>00037 <span class="comment"> * @{</span>
<a name="l00038"></a>00038 <span class="comment"> */</span>
<a name="l00039"></a>00039 <span class="comment"></span>
<a name="l00040"></a>00040 <span class="comment">/**</span>
<a name="l00041"></a>00041 <span class="comment"> * \defgroup uipsplit uIP TCP throughput booster hack</span>
<a name="l00042"></a>00042 <span class="comment"> * @{</span>
<a name="l00043"></a>00043 <span class="comment"> *</span>
<a name="l00044"></a>00044 <span class="comment"> * The basic uIP TCP implementation only allows each TCP connection to</span>
<a name="l00045"></a>00045 <span class="comment"> * have a single TCP segment in flight at any given time. Because of</span>
<a name="l00046"></a>00046 <span class="comment"> * the delayed ACK algorithm employed by most TCP receivers, uIP's</span>
<a name="l00047"></a>00047 <span class="comment"> * limit on the amount of in-flight TCP segments seriously reduces the</span>
<a name="l00048"></a>00048 <span class="comment"> * maximum achievable throughput for sending data from uIP.</span>
<a name="l00049"></a>00049 <span class="comment"> *</span>
<a name="l00050"></a>00050 <span class="comment"> * The uip-split module is a hack which tries to remedy this</span>
<a name="l00051"></a>00051 <span class="comment"> * situation. By splitting maximum sized outgoing TCP segments into</span>
<a name="l00052"></a>00052 <span class="comment"> * two, the delayed ACK algorithm is not invoked at TCP</span>
<a name="l00053"></a>00053 <span class="comment"> * receivers. This improves the throughput when sending data from uIP</span>
<a name="l00054"></a>00054 <span class="comment"> * by orders of magnitude.</span>
<a name="l00055"></a>00055 <span class="comment"> *</span>
<a name="l00056"></a>00056 <span class="comment"> * The uip-split module uses the uip-fw module (uIP IP packet</span>
<a name="l00057"></a>00057 <span class="comment"> * forwarding) for sending packets. Therefore, the uip-fw module must</span>
<a name="l00058"></a>00058 <span class="comment"> * be set up with the appropriate network interfaces for this module</span>
<a name="l00059"></a>00059 <span class="comment"> * to work.</span>
<a name="l00060"></a>00060 <span class="comment"> */</span>
<a name="l00061"></a>00061
<a name="l00062"></a>00062 <span class="comment"></span>
<a name="l00063"></a>00063 <span class="comment">/**</span>
<a name="l00064"></a>00064 <span class="comment"> * \file</span>
<a name="l00065"></a>00065 <span class="comment"> * Module for splitting outbound TCP segments in two to avoid the</span>
<a name="l00066"></a>00066 <span class="comment"> * delayed ACK throughput degradation.</span>
<a name="l00067"></a>00067 <span class="comment"> * \author</span>
<a name="l00068"></a>00068 <span class="comment"> * Adam Dunkels &lt;adam@sics.se&gt;</span>
<a name="l00069"></a>00069 <span class="comment"> *</span>
<a name="l00070"></a>00070 <span class="comment"> */</span>
<a name="l00071"></a>00071
<a name="l00072"></a>00072 <span class="preprocessor">#ifndef __UIP_SPLIT_H__</span>
<a name="l00073"></a>00073 <span class="preprocessor"></span><span class="preprocessor">#define __UIP_SPLIT_H__</span>
<a name="l00074"></a>00074 <span class="preprocessor"></span><span class="comment"></span>
<a name="l00075"></a>00075 <span class="comment">/**</span>
<a name="l00076"></a>00076 <span class="comment"> * Handle outgoing packets.</span>
<a name="l00077"></a>00077 <span class="comment"> *</span>
<a name="l00078"></a>00078 <span class="comment"> * This function inspects an outgoing packet in the uip_buf buffer and</span>
<a name="l00079"></a>00079 <span class="comment"> * sends it out using the uip_fw_output() function. If the packet is a</span>
<a name="l00080"></a>00080 <span class="comment"> * full-sized TCP segment it will be split into two segments and</span>
<a name="l00081"></a>00081 <span class="comment"> * transmitted separately. This function should be called instead of</span>
<a name="l00082"></a>00082 <span class="comment"> * the actual device driver output function, or the uip_fw_output()</span>
<a name="l00083"></a>00083 <span class="comment"> * function.</span>
<a name="l00084"></a>00084 <span class="comment"> *</span>
<a name="l00085"></a>00085 <span class="comment"> * The headers of the outgoing packet is assumed to be in the uip_buf</span>
<a name="l00086"></a>00086 <span class="comment"> * buffer and the payload is assumed to be wherever uip_appdata</span>
<a name="l00087"></a>00087 <span class="comment"> * points. The length of the outgoing packet is assumed to be in the</span>
<a name="l00088"></a>00088 <span class="comment"> * uip_len variable.</span>
<a name="l00089"></a>00089 <span class="comment"> *</span>
<a name="l00090"></a>00090 <span class="comment"> */</span>
<a name="l00091"></a>00091 <span class="keywordtype">void</span> <a class="code" href="a00154.html#gb4b17aaf20d630f30919b19937b966a3">uip_split_output</a>(<span class="keywordtype">void</span>);
<a name="l00092"></a>00092
<a name="l00093"></a>00093 <span class="preprocessor">#endif </span><span class="comment">/* __UIP_SPLIT_H__ */</span>
<a name="l00094"></a>00094 <span class="comment"></span>
<a name="l00095"></a>00095 <span class="comment">/** @} */</span><span class="comment"></span>
<a name="l00096"></a>00096 <span class="comment">/** @} */</span>
</pre></div><hr size="1"><address style="align: right;"><small>Generated on Mon Jun 12 10:23:01 2006 for uIP 1.0 by&nbsp;
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<img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.4.6 </small></address>
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