250 lines
9.2 KiB
Plaintext
250 lines
9.2 KiB
Plaintext
<!DOCTYPE book [
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<!ENTITY mdash "—">]>
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<!--
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- Copyright (C) 2000, 2001, 2004, 2005, 2007, 2014-2016 Internet Systems Consortium, Inc. ("ISC")
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-
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- This Source Code Form is subject to the terms of the Mozilla Public
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- License, v. 2.0. If a copy of the MPL was not distributed with this
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- file, You can obtain one at http://mozilla.org/MPL/2.0/.
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-->
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<!-- Converted by db4-upgrade version 1.0 -->
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<refentry xmlns:db="http://docbook.org/ns/docbook" version="5.0">
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<info>
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<date>2007-06-18</date>
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</info>
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<refentryinfo>
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<corpname>ISC</corpname>
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<corpauthor>Internet Systems Consortium, Inc.</corpauthor>
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</refentryinfo>
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<refmeta>
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<refentrytitle>lwres_gabn</refentrytitle>
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<manvolnum>3</manvolnum>
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<refmiscinfo>BIND9</refmiscinfo>
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</refmeta>
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<docinfo>
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<copyright>
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<year>2000</year>
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<year>2001</year>
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<year>2004</year>
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<year>2005</year>
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<year>2007</year>
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<year>2014</year>
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<year>2015</year>
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<year>2016</year>
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<holder>Internet Systems Consortium, Inc. ("ISC")</holder>
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</copyright>
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</docinfo>
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<refnamediv>
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<refname>lwres_gabnrequest_render</refname>
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<refname>lwres_gabnresponse_render</refname>
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<refname>lwres_gabnrequest_parse</refname>
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<refname>lwres_gabnresponse_parse</refname>
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<refname>lwres_gabnresponse_free</refname>
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<refname>lwres_gabnrequest_free</refname>
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<refpurpose>lightweight resolver getaddrbyname message handling</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <lwres/lwres.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>
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lwres_result_t
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<function>lwres_gabnrequest_render</function></funcdef>
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<paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
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<paramdef>lwres_gabnrequest_t *<parameter>req</parameter></paramdef>
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<paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
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<paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>
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lwres_result_t
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<function>lwres_gabnresponse_render</function></funcdef>
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<paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
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<paramdef>lwres_gabnresponse_t *<parameter>req</parameter></paramdef>
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<paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
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<paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>
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lwres_result_t
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<function>lwres_gabnrequest_parse</function></funcdef>
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<paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
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<paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
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<paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
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<paramdef>lwres_gabnrequest_t **<parameter>structp</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>
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lwres_result_t
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<function>lwres_gabnresponse_parse</function></funcdef>
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<paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
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<paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
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<paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
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<paramdef>lwres_gabnresponse_t **<parameter>structp</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>
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void
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<function>lwres_gabnresponse_free</function></funcdef>
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<paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
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<paramdef>lwres_gabnresponse_t **<parameter>structp</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>
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void
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<function>lwres_gabnrequest_free</function></funcdef>
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<paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
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<paramdef>lwres_gabnrequest_t **<parameter>structp</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsection><info><title>DESCRIPTION</title></info>
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<para>
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These are low-level routines for creating and parsing
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lightweight resolver name-to-address lookup request and
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response messages.
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</para>
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<para>
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There are four main functions for the getaddrbyname opcode.
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One render function converts a getaddrbyname request structure —
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<type>lwres_gabnrequest_t</type> —
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to the lightweight resolver's canonical format.
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It is complemented by a parse function that converts a packet in this
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canonical format to a getaddrbyname request structure.
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Another render function converts the getaddrbyname response structure
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— <type>lwres_gabnresponse_t</type> —
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to the canonical format.
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This is complemented by a parse function which converts a packet in
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canonical format to a getaddrbyname response structure.
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</para>
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<para>
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These structures are defined in
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<filename><lwres/lwres.h></filename>.
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They are shown below.
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</para>
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<para><programlisting>
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#define LWRES_OPCODE_GETADDRSBYNAME 0x00010001U
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</programlisting>
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</para>
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<para><programlisting>
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typedef struct lwres_addr lwres_addr_t;
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typedef LWRES_LIST(lwres_addr_t) lwres_addrlist_t;
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</programlisting>
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</para>
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<para><programlisting>
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typedef struct {
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lwres_uint32_t flags;
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lwres_uint32_t addrtypes;
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lwres_uint16_t namelen;
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char *name;
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} lwres_gabnrequest_t;
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</programlisting>
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</para>
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<para><programlisting>
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typedef struct {
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lwres_uint32_t flags;
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lwres_uint16_t naliases;
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lwres_uint16_t naddrs;
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char *realname;
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char **aliases;
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lwres_uint16_t realnamelen;
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lwres_uint16_t *aliaslen;
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lwres_addrlist_t addrs;
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void *base;
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size_t baselen;
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} lwres_gabnresponse_t;
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</programlisting>
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</para>
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<para><function>lwres_gabnrequest_render()</function>
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uses resolver context <parameter>ctx</parameter> to convert
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getaddrbyname request structure <parameter>req</parameter> to
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canonical format. The packet header structure
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<parameter>pkt</parameter> is initialised and transferred to
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buffer <parameter>b</parameter>.
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The contents of <parameter>*req</parameter> are then appended to
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the buffer in canonical format.
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<function>lwres_gabnresponse_render()</function> performs the
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same task, except it converts a getaddrbyname response structure
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<type>lwres_gabnresponse_t</type> to the lightweight resolver's
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canonical format.
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</para>
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<para><function>lwres_gabnrequest_parse()</function>
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uses context <parameter>ctx</parameter> to convert the contents
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of packet <parameter>pkt</parameter> to a
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<type>lwres_gabnrequest_t</type> structure. Buffer
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<parameter>b</parameter> provides space to be used for storing
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this structure. When the function succeeds, the resulting
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<type>lwres_gabnrequest_t</type> is made available through
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<parameter>*structp</parameter>.
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<function>lwres_gabnresponse_parse()</function> offers the same
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semantics as <function>lwres_gabnrequest_parse()</function>
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except it yields a <type>lwres_gabnresponse_t</type> structure.
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</para>
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<para><function>lwres_gabnresponse_free()</function>
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and <function>lwres_gabnrequest_free()</function> release the
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memory in resolver context <parameter>ctx</parameter> that was
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allocated to the <type>lwres_gabnresponse_t</type> or
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<type>lwres_gabnrequest_t</type> structures referenced via
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<parameter>structp</parameter>.
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Any memory associated with ancillary buffers and strings for
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those structures is also discarded.
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</para>
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</refsection>
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<refsection><info><title>RETURN VALUES</title></info>
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<para>
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The getaddrbyname opcode functions
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<function>lwres_gabnrequest_render()</function>,
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<function>lwres_gabnresponse_render()</function>
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<function>lwres_gabnrequest_parse()</function>
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and
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<function>lwres_gabnresponse_parse()</function>
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all return
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<errorcode>LWRES_R_SUCCESS</errorcode>
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on success.
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They return
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<errorcode>LWRES_R_NOMEMORY</errorcode>
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if memory allocation fails.
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<errorcode>LWRES_R_UNEXPECTEDEND</errorcode>
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is returned if the available space in the buffer
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<parameter>b</parameter>
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is too small to accommodate the packet header or the
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<type>lwres_gabnrequest_t</type>
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and
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<type>lwres_gabnresponse_t</type>
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structures.
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<function>lwres_gabnrequest_parse()</function>
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and
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<function>lwres_gabnresponse_parse()</function>
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will return
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<errorcode>LWRES_R_UNEXPECTEDEND</errorcode>
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if the buffer is not empty after decoding the received packet.
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These functions will return
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<errorcode>LWRES_R_FAILURE</errorcode>
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if
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<varname remap="structfield">pktflags</varname>
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in the packet header structure
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<type>lwres_lwpacket_t</type>
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indicate that the packet is not a response to an earlier query.
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</para>
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</refsection>
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<refsection><info><title>SEE ALSO</title></info>
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<para><citerefentry>
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<refentrytitle>lwres_packet</refentrytitle><manvolnum>3</manvolnum>
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</citerefentry>
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</para>
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</refsection>
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</refentry>
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