6ea1b817e31b89a627e146fe69e23ea0a64c89ecBob Halley<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

b0e8629055a766d4555a005a283c2889a5974945Mark Andrews "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"

75c0816e8295e180f4bc7f10db3d0d880383bc1cMark Andrews [<!ENTITY mdash "&#8212;">]>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

e21a2904f02a03fa06b6db04d348f65fe9c67b2bMark Andrews<refentry>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refentryinfo>

4abdfc917e6635a7c81d1f931a0c79227e72d025Mark Andrews <date>Jun 30, 2000</date>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refentryinfo>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refmeta>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refentrytitle>lwres_context</refentrytitle>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <manvolnum>3</manvolnum>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refmiscinfo>BIND9</refmiscinfo>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refmeta>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <docinfo>

b0e8629055a766d4555a005a283c2889a5974945Mark Andrews <copyright>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2004</year>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2005</year>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <year>2007</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 <year>2003</year>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <holder>Internet Software Consortium.</holder>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </copyright>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </docinfo>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refnamediv>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_context_create</refname>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_context_destroy</refname>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_context_nextserial</refname>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_context_initserial</refname>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_context_freemem</refname>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_context_allocmem</refname>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refname>lwres_context_sendrecv</refname>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refpurpose>lightweight resolver context management</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_context_create</function></funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_context_t **<parameter>contextp</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>void *<parameter>arg</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_malloc_t <parameter>malloc_function</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_free_t <parameter>free_function</parameter></paramdef>

b0e8629055a766d4555a005a283c2889a5974945Mark Andrews </funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_result_t

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_context_destroy</function></funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_context_t **<parameter>contextp</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinvoid

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_context_initserial</function></funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_uint32_t <parameter>serial</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinlwres_uint32_t

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_context_nextserial</function></funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinvoid

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_context_freemem</function></funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>void *<parameter>mem</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>size_t <parameter>len</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinvoid

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_context_allocmem</function></funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>size_t <parameter>len</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinvoid *

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<function>lwres_context_sendrecv</function></funcdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>void *<parameter>sendbase</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>int <parameter>sendlen</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>void *<parameter>recvbase</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>int <parameter>recvlen</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <paramdef>int *<parameter>recvd_len</parameter></paramdef>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </funcprototype>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein</funcsynopsis>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </refsynopsisdiv>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refsect1>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <title>DESCRIPTION</title>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para><function>lwres_context_create()</function>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein creates a <type>lwres_context_t</type> structure for use in

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein lightweight resolver operations. It holds a socket and other

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein data needed for communicating with a resolver daemon. The new

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>lwres_context_t</type> is returned through

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>contextp</parameter>, a pointer to a

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>lwres_context_t</type> pointer. This

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>lwres_context_t</type> pointer must initially be NULL, and

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is modified to point to the newly created

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <type>lwres_context_t</type>.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>

d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews <para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein When the lightweight resolver needs to perform dynamic memory

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allocation, it will call

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>malloc_function</parameter>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to allocate memory and

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>free_function</parameter>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to free it. If

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>malloc_function</parameter>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>free_function</parameter>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein are NULL, memory is allocated using

d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews <citerefentry>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refentrytitle>malloc</refentrytitle><manvolnum>3</manvolnum>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </citerefentry>.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <citerefentry>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refentrytitle>free</refentrytitle><manvolnum>3</manvolnum>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </citerefentry>.

d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein It is not permitted to have a NULL

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>malloc_function</parameter> and a non-NULL

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>free_function</parameter> or vice versa.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>arg</parameter> is passed as the first parameter to

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the memory allocation functions. If

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>malloc_function</parameter> and

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>free_function</parameter> are NULL,

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>arg</parameter> is unused and should be passed as

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein NULL.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews <para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Once memory for the structure has been allocated,

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein it is initialized using

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <citerefentry>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <refentrytitle>lwres_conf_init</refentrytitle><manvolnum>3</manvolnum>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </citerefentry>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and returned via <parameter>*contextp</parameter>.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para><function>lwres_context_destroy()</function>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein destroys a <type>lwres_context_t</type>, closing its socket.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>contextp</parameter> is a pointer to a pointer to the

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein context that is to be destroyed. The pointer will be set to

d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews NULL when the context has been destroyed.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein </para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <para>

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The context holds a serial number that is used to identify

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein resolver request packets and associate responses with the

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein corresponding requests. This serial number is controlled using

d71e2e0c61df16ff37c9934c371a4a60c08974f7Mark Andrews <function>lwres_context_initserial()</function> and

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <function>lwres_context_nextserial()</function>.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <function>lwres_context_initserial()</function> sets the serial

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein number for context <parameter>*ctx</parameter> to

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <parameter>serial</parameter>.

60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <function>lwres_context_nextserial()</function> increments the

serial number and returns the previous value.

</para>

<para>

Memory for a lightweight resolver context is allocated and freed

using <function>lwres_context_allocmem()</function> and

<function>lwres_context_freemem()</function>. These use

whatever allocations were defined when the context was created

with <function>lwres_context_create()</function>.

<function>lwres_context_allocmem()</function> allocates

<parameter>len</parameter> bytes of memory and if successful

returns a pointer to the allocated storage.

<function>lwres_context_freemem()</function> frees

<parameter>len</parameter> bytes of space starting at location

<parameter>mem</parameter>.

</para>

<para><function>lwres_context_sendrecv()</function>

performs I/O for the context <parameter>ctx</parameter>. Data

are read and written from the context's socket. It writes data

from <parameter>sendbase</parameter> &mdash; typically a

lightweight resolver query packet &mdash; and waits for a reply

which is copied to the receive buffer at

<parameter>recvbase</parameter>. The number of bytes that were

written to this receive buffer is returned in

<parameter>*recvd_len</parameter>.

</para>

</refsect1>

<refsect1>

<title>RETURN VALUES</title>

<para><function>lwres_context_create()</function>

returns <errorcode>LWRES_R_NOMEMORY</errorcode> if memory for

the <type>struct lwres_context</type> could not be allocated,

<errorcode>LWRES_R_SUCCESS</errorcode> otherwise.

</para>

<para>

Successful calls to the memory allocator

<function>lwres_context_allocmem()</function>

return a pointer to the start of the allocated space.

It returns NULL if memory could not be allocated.

</para>

<para><errorcode>LWRES_R_SUCCESS</errorcode>

is returned when

<function>lwres_context_sendrecv()</function>

completes successfully.

<errorcode>LWRES_R_IOERROR</errorcode>

is returned if an I/O error occurs and

<errorcode>LWRES_R_TIMEOUT</errorcode>

is returned if

<function>lwres_context_sendrecv()</function>

times out waiting for a response.

</para>

</refsect1>

<refsect1>

<title>SEE ALSO</title>

<para><citerefentry>

<refentrytitle>lwres_conf_init</refentrytitle><manvolnum>3</manvolnum>

</citerefentry>,

<citerefentry>

<refentrytitle>malloc</refentrytitle><manvolnum>3</manvolnum>

</citerefentry>,

<citerefentry>

<refentrytitle>free</refentrytitle><manvolnum>3</manvolnum>

</citerefentry>.

</para>

</refsect1>

</refentry><!--