00b67f09dd
Also known as ISC bind. This import adds utilities such as host(1), dig(1), and nslookup(1), as well as many other tools and libraries. Change-Id: I035ca46e64f1965d57019e773f4ff0ef035e4aa3
236 lines
9.0 KiB
HTML
236 lines
9.0 KiB
HTML
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- Copyright (C) 2004, 2005, 2007, 2014 Internet Systems Consortium, Inc. ("ISC")
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- Permission to use, copy, modify, and/or distribute this software for any
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<title>lwres_packet</title>
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<meta name="generator" content="DocBook XSL Stylesheets V1.71.1">
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</head>
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en">
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<a name="id2476275"></a><div class="titlepage"></div>
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<div class="refnamediv">
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<h2>Name</h2>
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<p>lwres_lwpacket_renderheader, lwres_lwpacket_parseheader — lightweight resolver packet handling functions</p>
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</div>
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<div class="refsynopsisdiv">
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<h2>Synopsis</h2>
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<div class="funcsynopsis">
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<pre class="funcsynopsisinfo">#include <lwres/lwpacket.h></pre>
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<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
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<tr>
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<td><code class="funcdef">
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lwres_result_t
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<b class="fsfunc">lwres_lwpacket_renderheader</b>(</code></td>
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<td>lwres_buffer_t * </td>
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<td>
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<var class="pdparam">b</var>, </td>
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</tr>
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<tr>
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<td> </td>
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<td>lwres_lwpacket_t * </td>
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<td>
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<var class="pdparam">pkt</var><code>)</code>;</td>
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</tr>
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</table>
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<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
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<tr>
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<td><code class="funcdef">
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lwres_result_t
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<b class="fsfunc">lwres_lwpacket_parseheader</b>(</code></td>
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<td>lwres_buffer_t * </td>
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<td>
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<var class="pdparam">b</var>, </td>
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</tr>
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<tr>
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<td> </td>
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<td>lwres_lwpacket_t * </td>
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<td>
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<var class="pdparam">pkt</var><code>)</code>;</td>
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</tr>
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</table>
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</div>
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</div>
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<div class="refsect1" lang="en">
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<a name="id2543399"></a><h2>DESCRIPTION</h2>
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<p>
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These functions rely on a
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<span class="type">struct lwres_lwpacket</span>
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which is defined in
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<code class="filename">lwres/lwpacket.h</code>.
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</p>
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<pre class="programlisting">
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typedef struct lwres_lwpacket lwres_lwpacket_t;
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</pre>
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<p>
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</p>
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<pre class="programlisting">
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struct lwres_lwpacket {
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lwres_uint32_t length;
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lwres_uint16_t version;
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lwres_uint16_t pktflags;
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lwres_uint32_t serial;
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lwres_uint32_t opcode;
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lwres_uint32_t result;
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lwres_uint32_t recvlength;
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lwres_uint16_t authtype;
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lwres_uint16_t authlength;
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};
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</pre>
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<p>
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</p>
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<p>
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The elements of this structure are:
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</p>
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<div class="variablelist"><dl>
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<dt><span class="term"><code class="constant">length</code></span></dt>
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<dd><p>
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the overall packet length, including the entire packet header.
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This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
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calls.
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</p></dd>
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<dt><span class="term"><code class="constant">version</code></span></dt>
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<dd><p>
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the header format. There is currently only one format,
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<span class="type">LWRES_LWPACKETVERSION_0</span>.
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This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
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calls.
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</p></dd>
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<dt><span class="term"><code class="constant">pktflags</code></span></dt>
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<dd><p>
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library-defined flags for this packet: for instance whether the
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packet
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is a request or a reply. Flag values can be set, but not defined
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by
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the caller.
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This field is filled in by the application wit the exception of
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the
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LWRES_LWPACKETFLAG_RESPONSE bit, which is set by the library in
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the
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lwres_gabn_*() and lwres_gnba_*() calls.
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</p></dd>
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<dt><span class="term"><code class="constant">serial</code></span></dt>
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<dd><p>
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is set by the requestor and is returned in all replies. If two
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or more
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packets from the same source have the same serial number and are
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from
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the same source, they are assumed to be duplicates and the
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latter ones
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may be dropped.
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This field must be set by the application.
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</p></dd>
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<dt><span class="term"><code class="constant">opcode</code></span></dt>
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<dd><p>
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indicates the operation.
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Opcodes between 0x00000000 and 0x03ffffff are
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reserved for use by the lightweight resolver library. Opcodes
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between
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0x04000000 and 0xffffffff are application defined.
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This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
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calls.
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</p></dd>
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<dt><span class="term"><code class="constant">result</code></span></dt>
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<dd><p>
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is only valid for replies.
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Results between 0x04000000 and 0xffffffff are application
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defined.
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Results between 0x00000000 and 0x03ffffff are reserved for
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library use.
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This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
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calls.
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</p></dd>
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<dt><span class="term"><code class="constant">recvlength</code></span></dt>
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<dd><p>
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is the maximum buffer size that the receiver can handle on
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requests
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and the size of the buffer needed to satisfy a request when the
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buffer
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is too large for replies.
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This field is supplied by the application.
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</p></dd>
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<dt><span class="term"><code class="constant">authtype</code></span></dt>
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<dd><p>
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defines the packet level authentication that is used.
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Authorisation types between 0x1000 and 0xffff are application
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defined
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and types between 0x0000 and 0x0fff are reserved for library
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use.
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Currently these are not used and must be zero.
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</p></dd>
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<dt><span class="term"><code class="constant">authlen</code></span></dt>
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<dd><p>
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gives the length of the authentication data.
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Since packet authentication is currently not used, this must be
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zero.
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</p></dd>
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</dl></div>
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<p>
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</p>
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<p>
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The following opcodes are currently defined:
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</p>
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<div class="variablelist"><dl>
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<dt><span class="term"><code class="constant">NOOP</code></span></dt>
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<dd><p>
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Success is always returned and the packet contents are echoed.
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The lwres_noop_*() functions should be used for this type.
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</p></dd>
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<dt><span class="term"><code class="constant">GETADDRSBYNAME</code></span></dt>
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<dd><p>
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returns all known addresses for a given name.
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The lwres_gabn_*() functions should be used for this type.
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</p></dd>
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<dt><span class="term"><code class="constant">GETNAMEBYADDR</code></span></dt>
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<dd><p>
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return the hostname for the given address.
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The lwres_gnba_*() functions should be used for this type.
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</p></dd>
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</dl></div>
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<p>
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</p>
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<p><code class="function">lwres_lwpacket_renderheader()</code>
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transfers the contents of lightweight resolver packet structure
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<span class="type">lwres_lwpacket_t</span> <em class="parameter"><code>*pkt</code></em> in
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network byte order to the lightweight resolver buffer,
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<em class="parameter"><code>*b</code></em>.
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</p>
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<p><code class="function">lwres_lwpacket_parseheader()</code>
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performs the converse operation. It transfers data in network
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byte order from buffer <em class="parameter"><code>*b</code></em> to resolver
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packet <em class="parameter"><code>*pkt</code></em>. The contents of the buffer
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<em class="parameter"><code>b</code></em> should correspond to a
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<span class="type">lwres_lwpacket_t</span>.
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</p>
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</div>
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<div class="refsect1" lang="en">
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<a name="id2543716"></a><h2>RETURN VALUES</h2>
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<p>
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Successful calls to
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<code class="function">lwres_lwpacket_renderheader()</code> and
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<code class="function">lwres_lwpacket_parseheader()</code> return
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<span class="errorcode">LWRES_R_SUCCESS</span>. If there is insufficient
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space to copy data between the buffer <em class="parameter"><code>*b</code></em> and
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lightweight resolver packet <em class="parameter"><code>*pkt</code></em> both
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functions
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return <span class="errorcode">LWRES_R_UNEXPECTEDEND</span>.
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</p>
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</div>
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</div></body>
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</html>
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