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add uip git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1125 bbd45198-f89e-11dd-88c7-29a3b14d5316
2010-11-27 00:27:45 +08:00
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<h1>uip/uip-split.c</h1><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.c,v 1.2 2006/06/12 08:00:30 adam Exp $</span>
<a name="l00034"></a>00034 <span class="comment"> */</span>
<a name="l00035"></a>00035
<a name="l00036"></a>00036 <span class="preprocessor">#include &lt;string.h&gt;</span>
<a name="l00037"></a>00037
<a name="l00038"></a>00038 <span class="preprocessor">#include "<a class="code" href="a00134.html">uip-split.h</a>"</span>
<a name="l00039"></a>00039 <span class="preprocessor">#include "<a class="code" href="a00136.html">uip.h</a>"</span>
<a name="l00040"></a>00040 <span class="preprocessor">#include "uip-fw.h"</span>
<a name="l00041"></a>00041 <span class="preprocessor">#include "<a class="code" href="a00137.html">uip_arch.h</a>"</span>
<a name="l00042"></a>00042
<a name="l00043"></a>00043
<a name="l00044"></a>00044
<a name="l00045"></a>00045 <span class="preprocessor">#define BUF ((struct uip_tcpip_hdr *)&amp;uip_buf[UIP_LLH_LEN])</span>
<a name="l00046"></a>00046 <span class="preprocessor"></span>
<a name="l00047"></a>00047 <span class="comment">/*-----------------------------------------------------------------------------*/</span>
<a name="l00048"></a>00048 <span class="keywordtype">void</span>
<a name="l00049"></a><a class="code" href="a00154.html#gb4b17aaf20d630f30919b19937b966a3">00049</a> <a class="code" href="a00154.html#gb4b17aaf20d630f30919b19937b966a3">uip_split_output</a>(<span class="keywordtype">void</span>)
<a name="l00050"></a>00050 {
<a name="l00051"></a>00051 <a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> tcplen, len1, len2;
<a name="l00052"></a>00052
<a name="l00053"></a>00053 <span class="comment">/* We only try to split maximum sized TCP segments. */</span>
<a name="l00054"></a>00054 <span class="keywordflow">if</span>(<a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;proto == <a class="code" href="a00150.html#g517c770991459cc62dc009c0d3875c6a">UIP_PROTO_TCP</a> &amp;&amp;
<a name="l00055"></a>00055 <a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> == <a class="code" href="a00153.html#g3589822ecb9d9c4145209756396b8a6b">UIP_BUFSIZE</a> - <a class="code" href="a00153.html#ge6f4a2453dbd8bc60e6a82774552366a">UIP_LLH_LEN</a>) {
<a name="l00056"></a>00056
<a name="l00057"></a>00057 tcplen = <a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> - <a class="code" href="a00150.html#gee37386b2ab828787c05227eb109def7">UIP_TCPIP_HLEN</a>;
<a name="l00058"></a>00058 <span class="comment">/* Split the segment in two. If the original packet length was</span>
<a name="l00059"></a>00059 <span class="comment"> odd, we make the second packet one byte larger. */</span>
<a name="l00060"></a>00060 len1 = len2 = tcplen / 2;
<a name="l00061"></a>00061 <span class="keywordflow">if</span>(len1 + len2 &lt; tcplen) {
<a name="l00062"></a>00062 ++len2;
<a name="l00063"></a>00063 }
<a name="l00064"></a>00064
<a name="l00065"></a>00065 <span class="comment">/* Create the first packet. This is done by altering the length</span>
<a name="l00066"></a>00066 <span class="comment"> field of the IP header and updating the checksums. */</span>
<a name="l00067"></a>00067 <a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> = len1 + UIP_TCPIP_HLEN;
<a name="l00068"></a>00068 <span class="preprocessor">#if UIP_CONF_IPV6</span>
<a name="l00069"></a>00069 <span class="preprocessor"></span> <span class="comment">/* For IPv6, the IP length field does not include the IPv6 IP header</span>
<a name="l00070"></a>00070 <span class="comment"> length. */</span>
<a name="l00071"></a>00071 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;len[0] = ((<a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> - <a class="code" href="a00150.html#g6bc12c6c7b56f73ce5d57abfdcdc6eb5">UIP_IPH_LEN</a>) &gt;&gt; 8);
<a name="l00072"></a>00072 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;len[1] = ((<a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> - <a class="code" href="a00150.html#g6bc12c6c7b56f73ce5d57abfdcdc6eb5">UIP_IPH_LEN</a>) &amp; 0xff);
<a name="l00073"></a>00073 <span class="preprocessor">#else </span><span class="comment">/* UIP_CONF_IPV6 */</span>
<a name="l00074"></a>00074 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;len[0] = <a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> &gt;&gt; 8;
<a name="l00075"></a>00075 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;len[1] = <a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> &amp; 0xff;
<a name="l00076"></a>00076 <span class="preprocessor">#endif </span><span class="comment">/* UIP_CONF_IPV6 */</span>
<a name="l00077"></a>00077
<a name="l00078"></a>00078 <span class="comment">/* Recalculate the TCP checksum. */</span>
<a name="l00079"></a>00079 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;tcpchksum = 0;
<a name="l00080"></a>00080 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;tcpchksum = ~(<a class="code" href="a00150.html#g85b65e38aa74eba18979156f97a94a87">uip_tcpchksum</a>());
<a name="l00081"></a>00081
<a name="l00082"></a>00082 <span class="preprocessor">#if !UIP_CONF_IPV6</span>
<a name="l00083"></a>00083 <span class="preprocessor"></span> <span class="comment">/* Recalculate the IP checksum. */</span>
<a name="l00084"></a>00084 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;ipchksum = 0;
<a name="l00085"></a>00085 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;ipchksum = ~(<a class="code" href="a00150.html#g2addf34c7d457c1a7899a7e2171ef1e9">uip_ipchksum</a>());
<a name="l00086"></a>00086 <span class="preprocessor">#endif </span><span class="comment">/* UIP_CONF_IPV6 */</span>
<a name="l00087"></a>00087
<a name="l00088"></a>00088 <span class="comment">/* Transmit the first packet. */</span>
<a name="l00089"></a>00089 <span class="comment">/* uip_fw_output();*/</span>
<a name="l00090"></a>00090 tcpip_output();
<a name="l00091"></a>00091
<a name="l00092"></a>00092 <span class="comment">/* Now, create the second packet. To do this, it is not enough to</span>
<a name="l00093"></a>00093 <span class="comment"> just alter the length field, but we must also update the TCP</span>
<a name="l00094"></a>00094 <span class="comment"> sequence number and point the uip_appdata to a new place in</span>
<a name="l00095"></a>00095 <span class="comment"> memory. This place is detemined by the length of the first</span>
<a name="l00096"></a>00096 <span class="comment"> packet (len1). */</span>
<a name="l00097"></a>00097 <a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> = len2 + UIP_TCPIP_HLEN;
<a name="l00098"></a>00098 <span class="preprocessor">#if UIP_CONF_IPV6</span>
<a name="l00099"></a>00099 <span class="preprocessor"></span> <span class="comment">/* For IPv6, the IP length field does not include the IPv6 IP header</span>
<a name="l00100"></a>00100 <span class="comment"> length. */</span>
<a name="l00101"></a>00101 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;len[0] = ((<a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> - <a class="code" href="a00150.html#g6bc12c6c7b56f73ce5d57abfdcdc6eb5">UIP_IPH_LEN</a>) &gt;&gt; 8);
<a name="l00102"></a>00102 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;len[1] = ((<a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> - <a class="code" href="a00150.html#g6bc12c6c7b56f73ce5d57abfdcdc6eb5">UIP_IPH_LEN</a>) &amp; 0xff);
<a name="l00103"></a>00103 <span class="preprocessor">#else </span><span class="comment">/* UIP_CONF_IPV6 */</span>
<a name="l00104"></a>00104 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;len[0] = <a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> &gt;&gt; 8;
<a name="l00105"></a>00105 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;len[1] = <a class="code" href="a00149.html#g12a33f0c09711167bdf3dd7d7cf8c5a1">uip_len</a> &amp; 0xff;
<a name="l00106"></a>00106 <span class="preprocessor">#endif </span><span class="comment">/* UIP_CONF_IPV6 */</span>
<a name="l00107"></a>00107
<a name="l00108"></a>00108 <span class="comment">/* uip_appdata += len1;*/</span>
<a name="l00109"></a>00109 memcpy(<a class="code" href="a00150.html#g561b8eda32e059d4e7397f776268cc63">uip_appdata</a>, (<a class="code" href="a00153.html#g4caecabca98b43919dd11be1c0d4cd8e">u8_t</a> *)<a class="code" href="a00150.html#g561b8eda32e059d4e7397f776268cc63">uip_appdata</a> + len1, len2);
<a name="l00110"></a>00110
<a name="l00111"></a>00111 <a class="code" href="a00150.html#g6832e4d2d046536b6472f7ac92340f68">uip_add32</a>(<a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;seqno, len1);
<a name="l00112"></a>00112 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;seqno[0] = <a class="code" href="a00151.html#g2a0cf5d86c58fab216414ce59bf1fea1">uip_acc32</a>[0];
<a name="l00113"></a>00113 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;seqno[1] = <a class="code" href="a00151.html#g2a0cf5d86c58fab216414ce59bf1fea1">uip_acc32</a>[1];
<a name="l00114"></a>00114 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;seqno[2] = <a class="code" href="a00151.html#g2a0cf5d86c58fab216414ce59bf1fea1">uip_acc32</a>[2];
<a name="l00115"></a>00115 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;seqno[3] = <a class="code" href="a00151.html#g2a0cf5d86c58fab216414ce59bf1fea1">uip_acc32</a>[3];
<a name="l00116"></a>00116
<a name="l00117"></a>00117 <span class="comment">/* Recalculate the TCP checksum. */</span>
<a name="l00118"></a>00118 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;tcpchksum = 0;
<a name="l00119"></a>00119 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;tcpchksum = ~(<a class="code" href="a00150.html#g85b65e38aa74eba18979156f97a94a87">uip_tcpchksum</a>());
<a name="l00120"></a>00120
<a name="l00121"></a>00121 <span class="preprocessor">#if !UIP_CONF_IPV6</span>
<a name="l00122"></a>00122 <span class="preprocessor"></span> <span class="comment">/* Recalculate the IP checksum. */</span>
<a name="l00123"></a>00123 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;ipchksum = 0;
<a name="l00124"></a>00124 <a class="code" href="a00150.html#g24f52ac52d6e714cb04a5aa01be3bdd0">BUF</a>-&gt;ipchksum = ~(<a class="code" href="a00150.html#g2addf34c7d457c1a7899a7e2171ef1e9">uip_ipchksum</a>());
<a name="l00125"></a>00125 <span class="preprocessor">#endif </span><span class="comment">/* UIP_CONF_IPV6 */</span>
<a name="l00126"></a>00126
<a name="l00127"></a>00127 <span class="comment">/* Transmit the second packet. */</span>
<a name="l00128"></a>00128 <span class="comment">/* uip_fw_output();*/</span>
<a name="l00129"></a>00129 tcpip_output();
<a name="l00130"></a>00130 } <span class="keywordflow">else</span> {
<a name="l00131"></a>00131 <span class="comment">/* uip_fw_output();*/</span>
<a name="l00132"></a>00132 tcpip_output();
<a name="l00133"></a>00133 }
<a name="l00134"></a>00134
<a name="l00135"></a>00135 }
<a name="l00136"></a>00136 <span class="comment">/*-----------------------------------------------------------------------------*/</span>
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