lwres_gnba.html revision e21a2904f02a03fa06b6db04d348f65fe9c67b2b
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - Copyright (C) 2004, 2005 Internet Systems Consortium, Inc. ("ISC")
75c0816e8295e180f4bc7f10db3d0d880383bc1cMark Andrews - Copyright (C) 2000, 2001 Internet Software Consortium.
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafsson - Permission to use, copy, modify, and distribute this software for any
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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e21a2904f02a03fa06b6db04d348f65fe9c67b2bMark Andrews<!-- $Id: lwres_gnba.html,v 1.22 2006/12/12 01:45:21 marka Exp $ -->
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">
e21a2904f02a03fa06b6db04d348f65fe9c67b2bMark Andrews<a name="id2476419"></a><div class="titlepage"></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p>lwres_gnbarequest_render, lwres_gnbaresponse_render, lwres_gnbarequest_parse, lwres_gnbaresponse_parse, lwres_gnbaresponse_free, lwres_gnbarequest_free — lightweight resolver getnamebyaddress message handling</p>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
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_gnbarequest_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_gnbaresponse_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<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_gnbarequest_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 address-to-name lookup request and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein response messages.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein There are four main functions for the getnamebyaddr opcode.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein One render function converts a getnamebyaddr request structure —
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gnbarequest_t</span> —
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to the lightweight 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 getnamebyaddr request structure.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Another render function converts the getnamebyaddr response structure
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 getnamebyaddr response structure.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein These structures are defined in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein They are shown below.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein#define LWRES_OPCODE_GETNAMEBYADDR 0x00010002U
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafssontypedef struct {
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint32_t flags;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_addr_t addr;
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafsson} lwres_gnbarequest_t;
ddccd5811feff696ba460dabfb666ce61040f545Andreas Gustafssontypedef struct {
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint32_t flags;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint16_t naliases;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson char *realname;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson char **aliases;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint16_t realnamelen;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson lwres_uint16_t *aliaslen;
8eea877894ea5bcf5cdd9ca124a8601ad421d753Andreas Gustafsson size_t baselen;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein} lwres_gnbaresponse_t;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><code class="function">lwres_gnbarequest_render()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein uses resolver context <code class="varname">ctx</code> to convert
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein getnamebyaddr request structure <code class="varname">req</code> to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein canonical format. The packet header structure
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="varname">pkt</code> is initialised and transferred to buffer
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="varname">b</code>. The contents of <code class="varname">*req</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein are then appended to the buffer in canonical format.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gnbaresponse_render()</code> performs the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein same task, except it converts a getnamebyaddr response structure
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gnbaresponse_t</span> to the lightweight resolver's
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein canonical format.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><code class="function">lwres_gnbarequest_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein uses context <code class="varname">ctx</code> to convert the contents of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gnbarequest_t</span> structure. Buffer
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="varname">b</code> provides space to be used for storing this
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein structure. When the function succeeds, the resulting
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gnbarequest_t</span> is made available through
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gnbaresponse_parse()</code> offers the same
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein semantics as <code class="function">lwres_gnbarequest_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein except it yields a <span class="type">lwres_gnbaresponse_t</span> structure.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><code class="function">lwres_gnbaresponse_free()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and <code class="function">lwres_gnbarequest_free()</code> release the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein memory in resolver context <code class="varname">ctx</code> that was
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allocated to the <span class="type">lwres_gnbaresponse_t</span> or
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="type">lwres_gnbarequest_t</span> structures referenced via
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="varname">structp</code>. Any memory associated with
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ancillary buffers and strings for those structures is also
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The getnamebyaddr opcode functions
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gnbarequest_render()</code>,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gnbaresponse_render()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gnbarequest_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gnbaresponse_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_gnbarequest_parse()</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="function">lwres_gnbaresponse_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>.