lwres_resutil.docbook revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
6ea1b817e31b89a627e146fe69e23ea0a64c89ecBob Halley<!--
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - Copyright (C) 2000, 2001, 2004, 2005, 2007, 2014-2016 Internet Systems Consortium, Inc. ("ISC")
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60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews<!-- Converted by db4-upgrade version 1.0 -->
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews<refentry xmlns="http://docbook.org/ns/docbook" version="5.0">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <info>
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews <date>2007-06-18</date>
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews </info>
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews <refentryinfo>
8a66318e41ed14c5a88130e8c362610e8faa2121Mark Andrews <corpname>ISC</corpname>
6ea1b817e31b89a627e146fe69e23ea0a64c89ecBob Halley <corpauthor>Internet Systems Consortium, Inc.</corpauthor>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refentryinfo>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refmeta>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refentrytitle>lwres_resutil</refentrytitle>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <manvolnum>3</manvolnum>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refmiscinfo>BIND9</refmiscinfo>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refmeta>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <docinfo>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <copyright>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2004</year>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2005</year>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2007</year>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2014</year>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2015</year>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2016</year>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <holder>Internet Systems Consortium, Inc. ("ISC")</holder>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </copyright>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <copyright>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2000</year>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2001</year>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <holder>Internet Software Consortium.</holder>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </copyright>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </docinfo>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refnamediv>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_string_parse</refname>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_addr_parse</refname>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_getaddrsbyname</refname>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_getnamebyaddr</refname>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refpurpose>lightweight resolver utility functions</refpurpose>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refnamediv>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refsynopsisdiv>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcsynopsis>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcsynopsisinfo>#include &lt;lwres/lwres.h&gt;</funcsynopsisinfo>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_string_parse</function></funcdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>char **<parameter>c</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_uint16_t *<parameter>len</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_addr_parse</function></funcdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_addr_t *<parameter>addr</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_getaddrsbyname</function></funcdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>const char *<parameter>name</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_uint32_t <parameter>addrtypes</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_gabnresponse_t **<parameter>structp</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_getnamebyaddr</function></funcdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_uint32_t <parameter>addrtype</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_uint16_t <parameter>addrlen</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>const unsigned char *<parameter>addr</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_gnbaresponse_t **<parameter>structp</parameter></paramdef>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein</funcsynopsis>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refsynopsisdiv>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refsection><info><title>DESCRIPTION</title></info>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para><function>lwres_string_parse()</function>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein retrieves a DNS-encoded string starting the current pointer of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lightweight resolver buffer <parameter>b</parameter>: i.e.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <constant>b-&gt;current</constant>. When the function returns,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the address of the first byte of the encoded string is returned
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein via <parameter>*c</parameter> and the length of that string is
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein given by <parameter>*len</parameter>. The buffer's current
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein pointer is advanced to point at the character following the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein string length, the encoded string, and the trailing
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>NULL</type> character.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para><function>lwres_addr_parse()</function>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein extracts an address from the buffer <parameter>b</parameter>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The buffer's current pointer <constant>b-&gt;current</constant>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is presumed to point at an encoded address: the address preceded
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein by a 32-bit protocol family identifier and a 16-bit length
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein field. The encoded address is copied to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <constant>addr-&gt;address</constant> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <constant>addr-&gt;length</constant> indicates the size in bytes
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein of the address that was copied.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <constant>b-&gt;current</constant> is advanced to point at the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein next byte of available data in the buffer following the encoded
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein address.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para><function>lwres_getaddrsbyname()</function>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and <function>lwres_getnamebyaddr()</function> use the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>lwres_gnbaresponse_t</type> structure defined below:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<para><programlisting>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeintypedef struct {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lwres_uint32_t flags;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lwres_uint16_t naliases;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lwres_uint16_t naddrs;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein char *realname;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein char **aliases;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lwres_uint16_t realnamelen;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lwres_uint16_t *aliaslen;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lwres_addrlist_t addrs;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein void *base;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein size_t baselen;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein} lwres_gabnresponse_t;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein</programlisting></para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The contents of this structure are not manipulated directly but
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein they are controlled through the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <citerefentry>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refentrytitle>lwres_gabn</refentrytitle><manvolnum>3</manvolnum>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </citerefentry>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein functions.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The lightweight resolver uses
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <function>lwres_getaddrsbyname()</function> to perform
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forward lookups.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Hostname <parameter>name</parameter> is looked up using the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein resolver
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein context <parameter>ctx</parameter> for memory allocation.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>addrtypes</parameter> is a bitmask indicating
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein which type of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein addresses are to be looked up. Current values for this bitmask are
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>LWRES_ADDRTYPE_V4</type> for IPv4 addresses and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>LWRES_ADDRTYPE_V6</type> for IPv6 addresses. Results of the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lookup are returned in <parameter>*structp</parameter>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para><function>lwres_getnamebyaddr()</function>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein performs reverse lookups. Resolver context
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>ctx</parameter> is used for memory allocation. The
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein address type is indicated by <parameter>addrtype</parameter>:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>LWRES_ADDRTYPE_V4</type> or
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>LWRES_ADDRTYPE_V6</type>. The address to be looked up is
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein given by <parameter>addr</parameter> and its length is
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>addrlen</parameter> bytes. The result of the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein function call is made available through
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>*structp</parameter>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refsection>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refsection><info><title>RETURN VALUES</title></info>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Successful calls to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <function>lwres_string_parse()</function>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <function>lwres_addr_parse()</function>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein return
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <errorcode>LWRES_R_SUCCESS.</errorcode>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Both functions return
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <errorcode>LWRES_R_FAILURE</errorcode>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein if the buffer is corrupt or
<errorcode>LWRES_R_UNEXPECTEDEND</errorcode>
if the buffer has less space than expected for the components of the
encoded string or address.
</para>
<para><function>lwres_getaddrsbyname()</function>
returns <errorcode>LWRES_R_SUCCESS</errorcode> on success and it
returns <errorcode>LWRES_R_NOTFOUND</errorcode> if the hostname
<parameter>name</parameter> could not be found.
</para>
<para><errorcode>LWRES_R_SUCCESS</errorcode>
is returned by a successful call to
<function>lwres_getnamebyaddr()</function>.
</para>
<para>
Both
<function>lwres_getaddrsbyname()</function>
and
<function>lwres_getnamebyaddr()</function>
return
<errorcode>LWRES_R_NOMEMORY</errorcode>
when memory allocation requests fail and
<errorcode>LWRES_R_UNEXPECTEDEND</errorcode>
if the buffers used for sending queries and receiving replies are too
small.
</para>
</refsection>
<refsection><info><title>SEE ALSO</title></info>
<para><citerefentry>
<refentrytitle>lwres_buffer</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>lwres_gabn</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>.
</para>
</refsection>
</refentry>