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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"><title>Procyon AVRlib: net/arp.c Source File</title><link href="dox.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.4.2 --><div class="qindex"><a class="qindex" href="main.html">Main Page</a> | <a class="qindex" href="modules.html">Modules</a> | <a class="qindex" href="annotated.html">Data Structures</a> | <a class="qindex" href="dirs.html">Directories</a> | <a class="qindex" href="files.html">File List</a> | <a class="qindex" href="functions.html">Data Fields</a> | <a class="qindex" href="globals.html">Globals</a></div><div class="nav"><a class="el" href="dir_000001.html">net</a></div><h1>arp.c</h1><a href="arp_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001 <span class="comment">/*! \file arp.c \brief ARP Protocol Library. */</span>00002 <span class="comment">//*****************************************************************************</span>00003 <span class="comment">//</span>00004 <span class="comment">// File Name : 'arp.c'</span>00005 <span class="comment">// Title : ARP Protocol Library</span>00006 <span class="comment">// Author : Pascal Stang</span>00007 <span class="comment">// Created : 9/7/2004</span>00008 <span class="comment">// Revised : 7/3/2005</span>00009 <span class="comment">// Version : 0.1</span>00010 <span class="comment">// Target MCU : Atmel AVR series</span>00011 <span class="comment">// Editor Tabs : 4</span>00012 <span class="comment">//</span>00013 <span class="comment">//*****************************************************************************</span>00014 00015 <span class="preprocessor">#include "<a class="code" href="global_8h.html">global.h</a>"</span>00016 <span class="preprocessor">#include "<a class="code" href="net_8h.html">net.h</a>"</span>00017 <span class="preprocessor">#include "<a class="code" href="nic_8h.html">nic.h</a>"</span>00018 <span class="preprocessor">#include "<a class="code" href="arp_8h.html">arp.h</a>"</span>00019 00020 <span class="preprocessor">#include "<a class="code" href="rprintf_8h.html">rprintf.h</a>"</span>00021 00022 <span class="comment">// global variables</span>00023 00024 <span class="keyword">struct </span>ArpEntry00025 {00026 uint32_t ipaddr; <span class="comment">//< remote-note IP address</span>00027 <span class="keyword">struct </span>netEthAddr ethaddr; <span class="comment">//< remote-node ethernet (hardware/mac) address</span>00028 uint8_t time; <span class="comment">//< time to live (in ARP table); this is decremented by arpTimer()</span>00029 };00030 00031 <span class="keyword">struct </span>ArpEntry ArpMyAddr; <span class="comment">//< my local interface information (IP and MAC address)</span>00032 <span class="keyword">struct </span>ArpEntry ArpTable[ARP_TABLE_SIZE];00033 00034 <a name="l00035"></a><a class="code" href="group__arp.html#ga0">00035</a> <span class="keywordtype">void</span> <a class="code" href="group__arp.html#ga0">arpInit</a>(<span class="keywordtype">void</span>)00036 {00037 u08 i;00038 <span class="comment">// initialize all ArpTable elements to unused</span>00039 <span class="keywordflow">for</span>(i=0; i<ARP_TABLE_SIZE; i++)00040 {00041 ArpTable[i].ipaddr = 0;00042 ArpTable[i].time = 0;00043 }00044 }00045 <a name="l00046"></a><a class="code" href="group__arp.html#ga1">00046</a> <span class="keywordtype">void</span> <a class="code" href="group__arp.html#ga1">arpSetAddress</a>(<span class="keyword">struct</span> netEthAddr* myeth, uint32_t myip)00047 {00048 <span class="comment">// set local address record</span>00049 ArpMyAddr.ethaddr = *myeth;00050 ArpMyAddr.ipaddr = myip;00051 }00052 <a name="l00053"></a><a class="code" href="group__arp.html#ga2">00053</a> <span class="keywordtype">void</span> <a class="code" href="group__arp.html#ga2">arpArpIn</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> len, <span class="keyword">struct</span> netEthArpHeader* packet)00054 {00055 <span class="comment">// for now, we just reply to requests</span>00056 <span class="comment">// need to add ARP cache</span>00057 <span class="keywordflow">if</span>( (packet->arp.dipaddr == <a class="code" href="group__net.html#ga26">HTONL</a>(ArpMyAddr.ipaddr)) &&00058 (packet->arp.opcode == <a class="code" href="group__net.html#ga2">htons</a>(ARP_OPCODE_REQUEST)) )00059 {00060 <span class="comment">// in ARP header</span>00061 <span class="comment">// copy sender's address info to dest. fields</span>00062 packet->arp.dhwaddr = packet->arp.shwaddr;00063 packet->arp.dipaddr = packet->arp.sipaddr;00064 <span class="comment">// fill in our information</span>00065 packet->arp.shwaddr = ArpMyAddr.ethaddr;00066 packet->arp.sipaddr = <a class="code" href="group__net.html#ga26">HTONL</a>(ArpMyAddr.ipaddr);00067 <span class="comment">// change op to reply</span>00068 packet->arp.opcode = <a class="code" href="group__net.html#ga2">htons</a>(ARP_OPCODE_REPLY);00069 00070 <span class="comment">// in ethernet header</span>00071 packet->eth.dest = packet->eth.src;00072 packet->eth.src = ArpMyAddr.ethaddr;00073 00074 <span class="comment">//rprintfProgStrM("Sending ARP Reply\r\n");</span>00075 <span class="comment">//arpPrintHeader( &packet->arp );</span>00076 00077 <span class="comment">// send reply!</span>00078 <a class="code" href="group__nic.html#ga1">nicSend</a>(len, (<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span>*)packet);00079 }00080 }00081 <a name="l00082"></a><a class="code" href="group__arp.html#ga3">00082</a> <span class="keywordtype">void</span> <a class="code" href="group__arp.html#ga3">arpIpIn</a>(<span class="keyword">struct</span> netEthIpHeader* packet)00083 {00084 int8_t index;00085 00086 <span class="comment">// check if sender is already present in arp table</span>00087 index = <a class="code" href="group__arp.html#ga6">arpMatchIp</a>(<a class="code" href="group__net.html#ga26">HTONL</a>(packet->ip.srcipaddr));00088 <span class="keywordflow">if</span>(index != -1)00089 {00090 <span class="comment">// sender's IP address found, update ARP entry</span>00091 ArpTable[index].ethaddr = packet->eth.src;00092 <span class="comment">// and we're done</span>00093 <span class="keywordflow">return</span>;00094 }00095 00096 <span class="comment">// sender was not present in table,</span>00097 <span class="comment">// must add in empty/expired slot</span>00098 <span class="keywordflow">for</span>(index=0; index<ARP_TABLE_SIZE; index++)00099 {00100 <span class="keywordflow">if</span>(!ArpTable[index].time)00101 {00102 <span class="comment">// write entry</span>00103 ArpTable[index].ethaddr = packet->eth.src;00104 ArpTable[index].ipaddr = <a class="code" href="group__net.html#ga26">HTONL</a>(packet->ip.srcipaddr);00105 ArpTable[index].time = ARP_CACHE_TIME_TO_LIVE;00106 <span class="comment">// and we're done</span>00107 <span class="keywordflow">return</span>;00108 }⌨️ 快捷键说明
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