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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>uIP 1.0: resolv.c</title><link href="doxygen.css" rel="stylesheet" type="text/css"><link href="tabs.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.4.6 --><div class="tabs"> <ul> <li><a href="main.html"><span>Main Page</span></a></li> <li><a href="modules.html"><span>Modules</span></a></li> <li><a href="classes.html"><span>Data Structures</span></a></li> <li><a href="files.html"><span>Files</span></a></li> <li><a href="examples.html"><span>Examples</span></a></li> </ul></div><h1>resolv.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"> * \addtogroup apps</span><a name="l00003"></a>00003 <span class="comment"> * @{</span><a name="l00004"></a>00004 <span class="comment"> */</span><a name="l00005"></a>00005 <span class="comment"></span><a name="l00006"></a>00006 <span class="comment">/**</span><a name="l00007"></a>00007 <span class="comment"> * \defgroup resolv DNS resolver</span><a name="l00008"></a>00008 <span class="comment"> * @{</span><a name="l00009"></a>00009 <span class="comment"> *</span><a name="l00010"></a>00010 <span class="comment"> * The uIP DNS resolver functions are used to lookup a hostname and</span><a name="l00011"></a>00011 <span class="comment"> * map it to a numerical IP address. It maintains a list of resolved</span><a name="l00012"></a>00012 <span class="comment"> * hostnames that can be queried with the resolv_lookup()</span><a name="l00013"></a>00013 <span class="comment"> * function. New hostnames can be resolved using the resolv_query()</span><a name="l00014"></a>00014 <span class="comment"> * function.</span><a name="l00015"></a>00015 <span class="comment"> *</span><a name="l00016"></a>00016 <span class="comment"> * When a hostname has been resolved (or found to be non-existant),</span><a name="l00017"></a>00017 <span class="comment"> * the resolver code calls a callback function called resolv_found()</span><a name="l00018"></a>00018 <span class="comment"> * that must be implemented by the module that uses the resolver.</span><a name="l00019"></a>00019 <span class="comment"> */</span><a name="l00020"></a>00020 <span class="comment"></span><a name="l00021"></a>00021 <span class="comment">/**</span><a name="l00022"></a>00022 <span class="comment"> * \file</span><a name="l00023"></a>00023 <span class="comment"> * DNS host name to IP address resolver.</span><a name="l00024"></a>00024 <span class="comment"> * \author Adam Dunkels <adam@dunkels.com></span><a name="l00025"></a>00025 <span class="comment"> *</span><a name="l00026"></a>00026 <span class="comment"> * This file implements a DNS host name to IP address resolver.</span><a name="l00027"></a>00027 <span class="comment"> */</span><a name="l00028"></a>00028 <a name="l00029"></a>00029 <span class="comment">/*</span><a name="l00030"></a>00030 <span class="comment"> * Copyright (c) 2002-2003, Adam Dunkels.</span><a name="l00031"></a>00031 <span class="comment"> * All rights reserved.</span><a name="l00032"></a>00032 <span class="comment"> *</span><a name="l00033"></a>00033 <span class="comment"> * Redistribution and use in source and binary forms, with or without</span><a name="l00034"></a>00034 <span class="comment"> * modification, are permitted provided that the following conditions</span><a name="l00035"></a>00035 <span class="comment"> * are met:</span><a name="l00036"></a>00036 <span class="comment"> * 1. Redistributions of source code must retain the above copyright</span><a name="l00037"></a>00037 <span class="comment"> * notice, this list of conditions and the following disclaimer.</span><a name="l00038"></a>00038 <span class="comment"> * 2. Redistributions in binary form must reproduce the above copyright</span><a name="l00039"></a>00039 <span class="comment"> * notice, this list of conditions and the following disclaimer in the</span><a name="l00040"></a>00040 <span class="comment"> * documentation and/or other materials provided with the distribution.</span><a name="l00041"></a>00041 <span class="comment"> * 3. The name of the author may not be used to endorse or promote</span><a name="l00042"></a>00042 <span class="comment"> * products derived from this software without specific prior</span><a name="l00043"></a>00043 <span class="comment"> * written permission.</span><a name="l00044"></a>00044 <span class="comment"> *</span><a name="l00045"></a>00045 <span class="comment"> * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS</span><a name="l00046"></a>00046 <span class="comment"> * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED</span><a name="l00047"></a>00047 <span class="comment"> * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE</span><a name="l00048"></a>00048 <span class="comment"> * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY</span><a name="l00049"></a>00049 <span class="comment"> * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL</span><a name="l00050"></a>00050 <span class="comment"> * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE</span><a name="l00051"></a>00051 <span class="comment"> * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS</span><a name="l00052"></a>00052 <span class="comment"> * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,</span><a name="l00053"></a>00053 <span class="comment"> * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING</span><a name="l00054"></a>00054 <span class="comment"> * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS</span><a name="l00055"></a>00055 <span class="comment"> * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.</span><a name="l00056"></a>00056 <span class="comment"> *</span><a name="l00057"></a>00057 <span class="comment"> * This file is part of the uIP TCP/IP stack.</span><a name="l00058"></a>00058 <span class="comment"> *</span><a name="l00059"></a>00059 <span class="comment"> * $Id: resolv.c,v 1.5 2006/06/11 21:46:37 adam Exp $</span><a name="l00060"></a>00060 <span class="comment"> *</span><a name="l00061"></a>00061 <span class="comment"> */</span><a name="l00062"></a>00062 <a name="l00063"></a>00063 <span class="preprocessor">#include "<a class="code" href="a00103.html">resolv.h</a>"</span><a name="l00064"></a>00064 <span class="preprocessor">#include "<a class="code" href="a00136.html">uip.h</a>"</span><a name="l00065"></a>00065 <a name="l00066"></a>00066 <span class="preprocessor">#include <string.h></span><a name="l00067"></a>00067 <a name="l00068"></a>00068 <span class="preprocessor">#ifndef NULL</span><a name="l00069"></a>00069 <span class="preprocessor"></span><span class="preprocessor">#define NULL (void *)0</span><a name="l00070"></a>00070 <span class="preprocessor"></span><span class="preprocessor">#endif </span><span class="comment">/* NULL */</span><a name="l00071"></a>00071 <span class="comment"></span><a name="l00072"></a>00072 <span class="comment">/** \internal The maximum number of retries when asking for a name. */</span><a name="l00073"></a>00073 <span class="preprocessor">#define MAX_RETRIES 8</span><a name="l00074"></a>00074 <span class="preprocessor"></span><span class="comment"></span><a name="l00075"></a>00075 <span class="comment">/** \internal The DNS message header. */</span><a name="l00076"></a>00076 <span class="keyword">struct </span>dns_hdr {<a name="l00077"></a>00077 <a name="a125"></a><a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> id;<a name="l00078"></a>00078 <a name="a126"></a><a class="code" href="a00153.html#g4caecabca98b43919dd11be1c0d4cd8e">u8_t</a> flags1, flags2;<a name="l00079"></a>00079 <span class="preprocessor">#define DNS_FLAG1_RESPONSE 0x80</span><a name="l00080"></a>00080 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG1_OPCODE_STATUS 0x10</span><a name="l00081"></a>00081 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG1_OPCODE_INVERSE 0x08</span><a name="l00082"></a>00082 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG1_OPCODE_STANDARD 0x00</span><a name="l00083"></a>00083 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG1_AUTHORATIVE 0x04</span><a name="l00084"></a>00084 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG1_TRUNC 0x02</span><a name="l00085"></a>00085 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG1_RD 0x01</span><a name="l00086"></a>00086 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG2_RA 0x80</span><a name="l00087"></a>00087 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG2_ERR_MASK 0x0f</span><a name="l00088"></a>00088 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG2_ERR_NONE 0x00</span><a name="l00089"></a>00089 <span class="preprocessor"></span><span class="preprocessor">#define DNS_FLAG2_ERR_NAME 0x03</span><a name="l00090"></a>00090 <span class="preprocessor"></span> <a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> numquestions;<a name="l00091"></a>00091 <a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> numanswers;<a name="l00092"></a>00092 <a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> numauthrr;<a name="l00093"></a>00093 <a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> numextrarr;<a name="l00094"></a>00094 };<a name="l00095"></a>00095 <span class="comment"></span><a name="l00096"></a>00096 <span class="comment">/** \internal The DNS answer message structure. */</span><a name="l00097"></a>00097 <span class="keyword">struct </span>dns_answer {<a name="l00098"></a>00098 <span class="comment">/* DNS answer record starts with either a domain name or a pointer</span><a name="l00099"></a>00099 <span class="comment"> to a name already present somewhere in the packet. */</span><a name="l00100"></a>00100 <a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> type;<a name="l00101"></a>00101 <a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> <span class="keyword">class</span>;<a name="l00102"></a>00102 <a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> ttl[2];<a name="l00103"></a>00103 <a class="code" href="a00153.html#g77570ac4fcab86864fa1916e55676da2">u16_t</a> len;<a name="l00104"></a>00104 <a name="a127"></a><a class="code" href="a00150.html#g1ef35301f43a5bbb9f89f07b5a36b9a0">uip_ipaddr_t</a> ipaddr;<a name="l00105"></a>00105 };<a name="l00106"></a>00106 <a name="l00107"></a>00107 <span class="keyword">struct </span>namemap {<a name="l00108"></a>00108 <span class="preprocessor">#define STATE_UNUSED 0</span><a name="l00109"></a>00109 <span class="preprocessor"></span><span class="preprocessor">#define STATE_NEW 1</span><a name="l00110"></a>00110 <span class="preprocessor"></span><span class="preprocessor">#define STATE_ASKING 2</span><a name="l00111"></a>00111 <span class="preprocessor"></span><span class="preprocessor">#define STATE_DONE 3</span><a name="l00112"></a>00112 <span class="preprocessor"></span><span class="preprocessor">#define STATE_ERROR 4</span><a name="l00113"></a>00113 <span class="preprocessor"></span> <a class="code" href="a00153.html#g4caecabca98b43919dd11be1c0d4cd8e">u8_t</a> state;<a name="l00114"></a>00114 <a class="code" href="a00153.html#g4caecabca98b43919dd11be1c0d4cd8e">u8_t</a> tmr;<a name="l00115"></a>00115 <a class="code" href="a00153.html#g4caecabca98b43919dd11be1c0d4cd8e">u8_t</a> retries;<a name="l00116"></a>00116 <a class="code" href="a00153.html#g4caecabca98b43919dd11be1c0d4cd8e">u8_t</a> seqno;<a name="l00117"></a>00117 <a class="code" href="a00153.html#g4caecabca98b43919dd11be1c0d4cd8e">u8_t</a> err;<a name="l00118"></a>00118 <span class="keywordtype">char</span> name[32];<a name="l00119"></a>00119 <a class="code" href="a00150.html#g1ef35301f43a5bbb9f89f07b5a36b9a0">uip_ipaddr_t</a> ipaddr;<a name="l00120"></a>00120 };<a name="l00121"></a>00121 <a name="l00122"></a>00122 <span class="preprocessor">#ifndef UIP_CONF_RESOLV_ENTRIES</span><a name="l00123"></a>00123 <span class="preprocessor"></span><span class="preprocessor">#define RESOLV_ENTRIES 4</span><a name="l00124"></a>00124 <span class="preprocessor"></span><span class="preprocessor">#else </span><span class="comment">/* UIP_CONF_RESOLV_ENTRIES */</span><a name="l00125"></a>00125 <span class="preprocessor">#define RESOLV_ENTRIES UIP_CONF_RESOLV_ENTRIES</span><a name="l00126"></a>00126 <span class="preprocessor"></span><span class="preprocessor">#endif </span><span class="comment">/* UIP_CONF_RESOLV_ENTRIES */</span><a name="l00127"></a>00127 <a name="l00128"></a>00128 <a name="l00129"></a>00129 <span class="keyword">static</span> <span class="keyword">struct </span>namemap names[<a name="a128"></a><a class="code" href="a00160.html#g221d37ccde7e3fd0dd2c2eb0a6b15493">RESOLV_ENTRIES</a>];<a name="l00130"></a>00130 <a name="l00131"></a>00131 <span class="keyword">static</span> <a class="code" href="a00153.html#g4caecabca98b43919dd11be1c0d4cd8e">u8_t</a> seqno;<a name="l00132"></a>00132 <a name="l00133"></a>00133 <span class="keyword">static</span> <span class="keyword">struct </span><a name="_a129"></a><a class="code" href="a00095.html">uip_udp_conn</a> *resolv_conn = <a name="a130"></a><a class="code" href="a00160.html#g070d2ce7b6bb7e5c05602aa8c308d0c4">NULL</a>;<a name="l00134"></a>00134 <a name="l00135"></a>00135 <a name="l00136"></a>00136 <span class="comment">/*---------------------------------------------------------------------------*/</span><span class="comment"></span><a name="l00137"></a>00137 <span class="comment">/** \internal</span><a name="l00138"></a>00138 <span class="comment"> * Walk through a compact encoded DNS name and return the end of it.</span><a name="l00139"></a>00139 <span class="comment"> *</span><a name="l00140"></a>00140 <span class="comment"> * \return The end of the name.</span><a name="l00141"></a>00141 <span class="comment"> */</span><a name="l00142"></a>00142 <span class="comment">/*---------------------------------------------------------------------------*/</span><a name="l00143"></a>00143 <span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *<a name="l00144"></a>00144 parse_name(<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *query)<a name="l00145"></a>00145 {<a name="l00146"></a>00146 <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> n;<a name="l00147"></a>00147 ⌨️ 快捷键说明
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