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IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 12 - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 13 - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 14 - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 15 - PERFORMANCE OF THIS SOFTWARE. 16--> 17<!-- Id --> 18<html> 19<head> 20<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 21<title>lwres_packet</title> 22<meta name="generator" content="DocBook XSL Stylesheets V1.71.1"> 23</head> 24<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en"> 25<a name="id2476275"></a><div class="titlepage"></div> 26<div class="refnamediv"> 27<h2>Name</h2> 28<p>lwres_lwpacket_renderheader, lwres_lwpacket_parseheader — lightweight resolver packet handling functions</p> 29</div> 30<div class="refsynopsisdiv"> 31<h2>Synopsis</h2> 32<div class="funcsynopsis"> 33<pre class="funcsynopsisinfo">#include <lwres/lwpacket.h></pre> 34<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"> 35<tr> 36<td><code class="funcdef"> 37lwres_result_t 38<b class="fsfunc">lwres_lwpacket_renderheader</b>(</code></td> 39<td>lwres_buffer_t *�</td> 40<td> 41<var class="pdparam">b</var>, </td> 42</tr> 43<tr> 44<td>�</td> 45<td>lwres_lwpacket_t *�</td> 46<td> 47<var class="pdparam">pkt</var><code>)</code>;</td> 48</tr> 49</table> 50<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"> 51<tr> 52<td><code class="funcdef"> 53lwres_result_t 54<b class="fsfunc">lwres_lwpacket_parseheader</b>(</code></td> 55<td>lwres_buffer_t *�</td> 56<td> 57<var class="pdparam">b</var>, </td> 58</tr> 59<tr> 60<td>�</td> 61<td>lwres_lwpacket_t *�</td> 62<td> 63<var class="pdparam">pkt</var><code>)</code>;</td> 64</tr> 65</table> 66</div> 67</div> 68<div class="refsect1" lang="en"> 69<a name="id2543399"></a><h2>DESCRIPTION</h2> 70<p> 71 These functions rely on a 72 <span class="type">struct lwres_lwpacket</span> 73 which is defined in 74 <code class="filename">lwres/lwpacket.h</code>. 75 </p> 76<pre class="programlisting"> 77typedef struct lwres_lwpacket lwres_lwpacket_t; 78 </pre> 79<p> 80 </p> 81<pre class="programlisting"> 82struct lwres_lwpacket { 83 lwres_uint32_t length; 84 lwres_uint16_t version; 85 lwres_uint16_t pktflags; 86 lwres_uint32_t serial; 87 lwres_uint32_t opcode; 88 lwres_uint32_t result; 89 lwres_uint32_t recvlength; 90 lwres_uint16_t authtype; 91 lwres_uint16_t authlength; 92}; 93</pre> 94<p> 95 </p> 96<p> 97 The elements of this structure are: 98 </p> 99<div class="variablelist"><dl> 100<dt><span class="term"><code class="constant">length</code></span></dt> 101<dd><p> 102 the overall packet length, including the entire packet header. 103 This field is filled in by the lwres_gabn_*() and lwres_gnba_*() 104 calls. 105 </p></dd> 106<dt><span class="term"><code class="constant">version</code></span></dt> 107<dd><p> 108 the header format. There is currently only one format, 109 <span class="type">LWRES_LWPACKETVERSION_0</span>. 110 111 This field is filled in by the lwres_gabn_*() and lwres_gnba_*() 112 calls. 113 </p></dd> 114<dt><span class="term"><code class="constant">pktflags</code></span></dt> 115<dd><p> 116 library-defined flags for this packet: for instance whether the 117 packet 118 is a request or a reply. Flag values can be set, but not defined 119 by 120 the caller. 121 This field is filled in by the application wit the exception of 122 the 123 LWRES_LWPACKETFLAG_RESPONSE bit, which is set by the library in 124 the 125 lwres_gabn_*() and lwres_gnba_*() calls. 126 </p></dd> 127<dt><span class="term"><code class="constant">serial</code></span></dt> 128<dd><p> 129 is set by the requestor and is returned in all replies. If two 130 or more 131 packets from the same source have the same serial number and are 132 from 133 the same source, they are assumed to be duplicates and the 134 latter ones 135 may be dropped. 136 This field must be set by the application. 137 </p></dd> 138<dt><span class="term"><code class="constant">opcode</code></span></dt> 139<dd><p> 140 indicates the operation. 141 Opcodes between 0x00000000 and 0x03ffffff are 142 reserved for use by the lightweight resolver library. Opcodes 143 between 144 0x04000000 and 0xffffffff are application defined. 145 This field is filled in by the lwres_gabn_*() and lwres_gnba_*() 146 calls. 147 </p></dd> 148<dt><span class="term"><code class="constant">result</code></span></dt> 149<dd><p> 150 is only valid for replies. 151 Results between 0x04000000 and 0xffffffff are application 152 defined. 153 Results between 0x00000000 and 0x03ffffff are reserved for 154 library use. 155 This field is filled in by the lwres_gabn_*() and lwres_gnba_*() 156 calls. 157 </p></dd> 158<dt><span class="term"><code class="constant">recvlength</code></span></dt> 159<dd><p> 160 is the maximum buffer size that the receiver can handle on 161 requests 162 and the size of the buffer needed to satisfy a request when the 163 buffer 164 is too large for replies. 165 This field is supplied by the application. 166 </p></dd> 167<dt><span class="term"><code class="constant">authtype</code></span></dt> 168<dd><p> 169 defines the packet level authentication that is used. 170 Authorisation types between 0x1000 and 0xffff are application 171 defined 172 and types between 0x0000 and 0x0fff are reserved for library 173 use. 174 Currently these are not used and must be zero. 175 </p></dd> 176<dt><span class="term"><code class="constant">authlen</code></span></dt> 177<dd><p> 178 gives the length of the authentication data. 179 Since packet authentication is currently not used, this must be 180 zero. 181 </p></dd> 182</dl></div> 183<p> 184 </p> 185<p> 186 The following opcodes are currently defined: 187 </p> 188<div class="variablelist"><dl> 189<dt><span class="term"><code class="constant">NOOP</code></span></dt> 190<dd><p> 191 Success is always returned and the packet contents are echoed. 192 The lwres_noop_*() functions should be used for this type. 193 </p></dd> 194<dt><span class="term"><code class="constant">GETADDRSBYNAME</code></span></dt> 195<dd><p> 196 returns all known addresses for a given name. 197 The lwres_gabn_*() functions should be used for this type. 198 </p></dd> 199<dt><span class="term"><code class="constant">GETNAMEBYADDR</code></span></dt> 200<dd><p> 201 return the hostname for the given address. 202 The lwres_gnba_*() functions should be used for this type. 203 </p></dd> 204</dl></div> 205<p> 206 </p> 207<p><code class="function">lwres_lwpacket_renderheader()</code> 208 transfers the contents of lightweight resolver packet structure 209 <span class="type">lwres_lwpacket_t</span> <em class="parameter"><code>*pkt</code></em> in 210 network byte order to the lightweight resolver buffer, 211 <em class="parameter"><code>*b</code></em>. 212 </p> 213<p><code class="function">lwres_lwpacket_parseheader()</code> 214 performs the converse operation. It transfers data in network 215 byte order from buffer <em class="parameter"><code>*b</code></em> to resolver 216 packet <em class="parameter"><code>*pkt</code></em>. The contents of the buffer 217 <em class="parameter"><code>b</code></em> should correspond to a 218 <span class="type">lwres_lwpacket_t</span>. 219 </p> 220</div> 221<div class="refsect1" lang="en"> 222<a name="id2543716"></a><h2>RETURN VALUES</h2> 223<p> 224 Successful calls to 225 <code class="function">lwres_lwpacket_renderheader()</code> and 226 <code class="function">lwres_lwpacket_parseheader()</code> return 227 <span class="errorcode">LWRES_R_SUCCESS</span>. If there is insufficient 228 space to copy data between the buffer <em class="parameter"><code>*b</code></em> and 229 lightweight resolver packet <em class="parameter"><code>*pkt</code></em> both 230 functions 231 return <span class="errorcode">LWRES_R_UNEXPECTEDEND</span>. 232 </p> 233</div> 234</div></body> 235</html> 236