lwres_gabn.html revision ea94d370123a5892f6c47a97f21d1b28d44bb168
b0e8629055a766d4555a005a283c2889a5974945Mark Andrews - Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
75c0816e8295e180f4bc7f10db3d0d880383bc1cMark Andrews - Copyright (C) 2000, 2001 Internet Software Consortium.
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ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafsson - purpose with or without fee is hereby granted, provided that the above
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafsson - copyright notice and this permission notice appear in all copies.
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60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en">
ea94d370123a5892f6c47a97f21d1b28d44bb168Tinderbox User<a name="id2476274"></a><div class="titlepage"></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p>lwres_gabnrequest_render, lwres_gabnresponse_render, lwres_gabnrequest_parse, lwres_gabnresponse_parse, lwres_gabnresponse_free, lwres_gabnrequest_free — lightweight resolver getaddrbyname message handling</p>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<pre class="funcsynopsisinfo">#include <lwres/lwres.h></pre>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<b class="fsfunc">lwres_gabnrequest_render</b>(</code></td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<b class="fsfunc">lwres_gabnresponse_render</b>(</code></td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<b class="fsfunc">lwres_gabnrequest_parse</b>(</code></td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<var class="pdparam">structp</var><code>)</code>;</td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<b class="fsfunc">lwres_gabnresponse_parse</b>(</code></td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<var class="pdparam">structp</var><code>)</code>;</td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<b class="fsfunc">lwres_gabnresponse_free</b>(</code></td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<var class="pdparam">structp</var><code>)</code>;</td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<b class="fsfunc">lwres_gabnrequest_free</b>(</code></td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<var class="pdparam">structp</var><code>)</code>;</td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein These are low-level routines for creating and parsing
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lightweight resolver name-to-address lookup request and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein response messages.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein There are four main functions for the getaddrbyname opcode.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein One render function converts a getaddrbyname request structure —
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gabnrequest_t</span> —
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to the lighweight resolver's canonical format.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein It is complemented by a parse function that converts a packet in this
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein canonical format to a getaddrbyname request structure.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Another render function converts the getaddrbyname response structure
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein — <span class="type">lwres_gabnresponse_t</span> —
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to the canonical format.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This is complemented by a parse function which converts a packet in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein canonical format to a getaddrbyname response structure.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein These structures are defined in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="filename"><lwres/lwres.h></code>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein They are shown below.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein#define LWRES_OPCODE_GETADDRSBYNAME 0x00010001U
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafssontypedef struct lwres_addr lwres_addr_t;
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafssontypedef LWRES_LIST(lwres_addr_t) lwres_addrlist_t;
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafssontypedef struct {
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint32_t flags;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint32_t addrtypes;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint16_t namelen;
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafsson} lwres_gabnrequest_t;
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafssontypedef struct {
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint32_t flags;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint16_t naliases;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint16_t naddrs;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson char *realname;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson char **aliases;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint16_t realnamelen;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint16_t *aliaslen;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_addrlist_t addrs;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson size_t baselen;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein} lwres_gabnresponse_t;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><code class="function">lwres_gabnrequest_render()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein uses resolver context <em class="parameter"><code>ctx</code></em> to convert
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein getaddrbyname request structure <em class="parameter"><code>req</code></em> to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein canonical format. The packet header structure
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="parameter"><code>pkt</code></em> is initialised and transferred to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein buffer <em class="parameter"><code>b</code></em>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The contents of <em class="parameter"><code>*req</code></em> are then appended to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the buffer in canonical format.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gabnresponse_render()</code> performs the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein same task, except it converts a getaddrbyname response structure
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gabnresponse_t</span> to the lightweight resolver's
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein canonical format.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><code class="function">lwres_gabnrequest_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein uses context <em class="parameter"><code>ctx</code></em> to convert the contents
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein of packet <em class="parameter"><code>pkt</code></em> to a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gabnrequest_t</span> structure. Buffer
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="parameter"><code>b</code></em> provides space to be used for storing
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein this structure. When the function succeeds, the resulting
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gabnrequest_t</span> is made available through
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="parameter"><code>*structp</code></em>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gabnresponse_parse()</code> offers the same
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein semantics as <code class="function">lwres_gabnrequest_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein except it yields a <span class="type">lwres_gabnresponse_t</span> structure.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><code class="function">lwres_gabnresponse_free()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and <code class="function">lwres_gabnrequest_free()</code> release the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein memory in resolver context <em class="parameter"><code>ctx</code></em> that was
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allocated to the <span class="type">lwres_gabnresponse_t</span> or
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gabnrequest_t</span> structures referenced via
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="parameter"><code>structp</code></em>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Any memory associated with ancillary buffers and strings for
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein those structures is also discarded.
ea94d370123a5892f6c47a97f21d1b28d44bb168Tinderbox User<a name="id2543669"></a><h2>RETURN VALUES</h2>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The getaddrbyname opcode functions
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gabnrequest_render()</code>,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gabnresponse_render()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gabnrequest_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gabnresponse_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein if memory allocation fails.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="errorcode">LWRES_R_UNEXPECTEDEND</span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is returned if the available space in the buffer
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is too small to accommodate the packet header or the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gabnrequest_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gabnresponse_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="errorcode">LWRES_R_UNEXPECTEDEND</span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein if the buffer is not empty after decoding the received packet.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein These functions will return
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="structfield"><code>pktflags</code></em>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein in the packet header structure
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein indicate that the packet is not a response to an earlier query.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><span class="citerefentry"><span class="refentrytitle">lwres_packet</span>(3)</span>