132N/A<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

132N/A "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"

132N/A [<!ENTITY mdash "&#8212;">]>

132N/A

132N/A<refentry>

132N/A

132N/A <refentryinfo>

215N/A <date>Jun 30, 2000</date>

132N/A </refentryinfo>

132N/A

132N/A <refmeta>

132N/A <refentrytitle>lwres_resutil</refentrytitle>

132N/A <manvolnum>3</manvolnum>

132N/A <refmiscinfo>BIND9</refmiscinfo>

132N/A </refmeta>

132N/A

132N/A <docinfo>

132N/A <copyright>

132N/A <year>2004</year>

132N/A <year>2005</year>

132N/A <year>2007</year>

132N/A <holder>Internet Systems Consortium, Inc. ("ISC")</holder>

132N/A </copyright>

132N/A <copyright>

132N/A <year>2000</year>

132N/A <year>2001</year>

132N/A <holder>Internet Software Consortium.</holder>

132N/A </copyright>

132N/A </docinfo>

132N/A

132N/A <refnamediv>

132N/A <refname>lwres_string_parse</refname>

132N/A <refname>lwres_addr_parse</refname>

132N/A <refname>lwres_getaddrsbyname</refname>

132N/A <refname>lwres_getnamebyaddr</refname>

132N/A <refpurpose>lightweight resolver utility functions</refpurpose>

132N/A </refnamediv>

132N/A <refsynopsisdiv>

132N/A <funcsynopsis>

132N/A<funcsynopsisinfo>#include &lt;lwres/lwres.h&gt;</funcsynopsisinfo>

132N/A<funcprototype>

132N/A <funcdef>

132N/Alwres_result_t

132N/A<function>lwres_string_parse</function></funcdef>

132N/A <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>

132N/A <paramdef>char **<parameter>c</parameter></paramdef>

132N/A <paramdef>lwres_uint16_t *<parameter>len</parameter></paramdef>

132N/A </funcprototype>

132N/A<funcprototype>

132N/A <funcdef>

132N/Alwres_result_t

132N/A<function>lwres_addr_parse</function></funcdef>

132N/A <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>

132N/A <paramdef>lwres_addr_t *<parameter>addr</parameter></paramdef>

132N/A </funcprototype>

132N/A<funcprototype>

132N/A <funcdef>

132N/Alwres_result_t

132N/A<function>lwres_getaddrsbyname</function></funcdef>

132N/A <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>

132N/A <paramdef>const char *<parameter>name</parameter></paramdef>

132N/A <paramdef>lwres_uint32_t <parameter>addrtypes</parameter></paramdef>

132N/A <paramdef>lwres_gabnresponse_t **<parameter>structp</parameter></paramdef>

132N/A </funcprototype>

132N/A<funcprototype>

132N/A <funcdef>

132N/Alwres_result_t

132N/A<function>lwres_getnamebyaddr</function></funcdef>

132N/A <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>

132N/A <paramdef>lwres_uint32_t <parameter>addrtype</parameter></paramdef>

132N/A <paramdef>lwres_uint16_t <parameter>addrlen</parameter></paramdef>

132N/A <paramdef>const unsigned char *<parameter>addr</parameter></paramdef>

219N/A <paramdef>lwres_gnbaresponse_t **<parameter>structp</parameter></paramdef>

620N/A </funcprototype>

220N/A</funcsynopsis>

341N/A </refsynopsisdiv>

341N/A

379N/A <refsect1>

411N/A <title>DESCRIPTION</title>

487N/A

487N/A <para><function>lwres_string_parse()</function>

704N/A retrieves a DNS-encoded string starting the current pointer of

487N/A lightweight resolver buffer <parameter>b</parameter>: i.e.

704N/A <constant>b-&gt;current</constant>. When the function returns,

704N/A the address of the first byte of the encoded string is returned

487N/A via <parameter>*c</parameter> and the length of that string is

487N/A given by <parameter>*len</parameter>. The buffer's current

487N/A pointer is advanced to point at the character following the

320N/A string length, the encoded string, and the trailing

336N/A <type>NULL</type> character.

336N/A </para>

336N/A

336N/A <para><function>lwres_addr_parse()</function>

336N/A extracts an address from the buffer <parameter>b</parameter>.

336N/A The buffer's current pointer <constant>b-&gt;current</constant>

336N/A is presumed to point at an encoded address: the address preceded

341N/A by a 32-bit protocol family identifier and a 16-bit length

487N/A field. The encoded address is copied to

336N/A <constant>addr-&gt;address</constant> and

336N/A <constant>addr-&gt;length</constant> indicates the size in bytes

336N/A of the address that was copied.

379N/A <constant>b-&gt;current</constant> is advanced to point at the

379N/A next byte of available data in the buffer following the encoded

487N/A address.

379N/A </para>

379N/A

379N/A <para><function>lwres_getaddrsbyname()</function>

411N/A and <function>lwres_getnamebyaddr()</function> use the

411N/A <type>lwres_gnbaresponse_t</type> structure defined below:

487N/A </para>

411N/A

411N/A<para><programlisting>

411N/Atypedef struct {

320N/A lwres_uint32_t flags;

336N/A lwres_uint16_t naliases;

320N/A lwres_uint16_t naddrs;

336N/A char *realname;

320N/A char **aliases;

320N/A lwres_uint16_t realnamelen;

132N/A lwres_uint16_t *aliaslen;

132N/A lwres_addrlist_t addrs;

132N/A void *base;

132N/A size_t baselen;

132N/A} lwres_gabnresponse_t;

132N/A</programlisting></para>

671N/A

671N/A <para>

132N/A The contents of this structure are not manipulated directly but

132N/A they are controlled through the

132N/A <citerefentry>

132N/A <refentrytitle>lwres_gabn</refentrytitle><manvolnum>3</manvolnum>

244N/A </citerefentry>

244N/A functions.

132N/A </para>

132N/A

132N/A <para>

132N/A The lightweight resolver uses

190N/A <function>lwres_getaddrsbyname()</function> to perform

132N/A foward lookups.

132N/A Hostname <parameter>name</parameter> is looked up using the

132N/A resolver

132N/A context <parameter>ctx</parameter> for memory allocation.

132N/A <parameter>addrtypes</parameter> is a bitmask indicating

132N/A which type of

132N/A addresses are to be looked up. Current values for this bitmask are

132N/A <type>LWRES_ADDRTYPE_V4</type> for IPv4 addresses and

230N/A <type>LWRES_ADDRTYPE_V6</type> for IPv6 addresses. Results of the

230N/A lookup are returned in <parameter>*structp</parameter>.

230N/A </para>

230N/A

230N/A <para><function>lwres_getnamebyaddr()</function>

230N/A performs reverse lookups. Resolver context

230N/A <parameter>ctx</parameter> is used for memory allocation. The

230N/A address type is indicated by <parameter>addrtype</parameter>:

230N/A <type>LWRES_ADDRTYPE_V4</type> or

230N/A <type>LWRES_ADDRTYPE_V6</type>. The address to be looked up is

230N/A given by <parameter>addr</parameter> and its length is

230N/A <parameter>addrlen</parameter> bytes. The result of the

230N/A function call is made available through

230N/A <parameter>*structp</parameter>.

230N/A </para>

230N/A </refsect1>

230N/A

230N/A <refsect1>

230N/A <title>RETURN VALUES</title>

230N/A <para>

230N/A Successful calls to

230N/A <function>lwres_string_parse()</function>

230N/A and

230N/A <function>lwres_addr_parse()</function>

230N/A return

230N/A <errorcode>LWRES_R_SUCCESS.</errorcode>

230N/A Both functions return

230N/A <errorcode>LWRES_R_FAILURE</errorcode>

230N/A if the buffer is corrupt or

230N/A <errorcode>LWRES_R_UNEXPECTEDEND</errorcode>

301N/A if the buffer has less space than expected for the components of the

132N/A encoded string or address.

132N/A </para>

132N/A

213N/A <para><function>lwres_getaddrsbyname()</function>

301N/A returns <errorcode>LWRES_R_SUCCESS</errorcode> on success and it

132N/A returns <errorcode>LWRES_R_NOTFOUND</errorcode> if the hostname

132N/A <parameter>name</parameter> could not be found.

211N/A </para>

213N/A <para><errorcode>LWRES_R_SUCCESS</errorcode>

213N/A is returned by a successful call to

213N/A <function>lwres_getnamebyaddr()</function>.

213N/A </para>

213N/A

213N/A <para>

213N/A Both

213N/A <function>lwres_getaddrsbyname()</function>

487N/A and

213N/A <function>lwres_getnamebyaddr()</function>

213N/A return

213N/A <errorcode>LWRES_R_NOMEMORY</errorcode>

213N/A when memory allocation requests fail and

213N/A <errorcode>LWRES_R_UNEXPECTEDEND</errorcode>

213N/A if the buffers used for sending queries and receiving replies are too

213N/A small.

213N/A </para>

213N/A

213N/A </refsect1>

213N/A <refsect1>

213N/A <title>SEE ALSO</title>

213N/A <para><citerefentry>

213N/A <refentrytitle>lwres_buffer</refentrytitle><manvolnum>3</manvolnum>

213N/A </citerefentry>,

213N/A

213N/A <citerefentry>

213N/A <refentrytitle>lwres_gabn</refentrytitle><manvolnum>3</manvolnum>

213N/A </citerefentry>.

213N/A </para>

213N/A

213N/A </refsect1>

230N/A</refentry><!--

211N/A