<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN">

<refentry>

<refentryinfo>

<date>Oct 18, 2000</date>

</refentryinfo>

<refmeta>

<refentrytitle>lwres_getrrsetbyname</refentrytitle>

<manvolnum>3</manvolnum>

<refmiscinfo>BIND9</refmiscinfo>

</refmeta>

<refnamediv>

<refname>lwres_getrrsetbyname</refname>

<refname>lwres_freerrset</refname>

<refpurpose>retrieve DNS records</refpurpose>

</refnamediv>

<refsynopsisdiv>

<funcsynopsis>

<funcsynopsisinfo>#include &lt;lwres/netdb.h&gt;</funcsynopsisinfo>

<funcprototype>

<funcdef>

int

<function>lwres_getrrsetbyname</function></funcdef>

<paramdef>const char *hostname</paramdef>

<paramdef>unsigned int rdclass</paramdef>

<paramdef>unsigned int rdtype</paramdef>

<paramdef>unsigned int flags</paramdef>

<paramdef>struct rrsetinfo **res</paramdef>

</funcprototype>

<funcprototype>

<funcdef>

void

<function>lwres_freerrset</function></funcdef>

<paramdef>struct rrsetinfo *rrset</paramdef>

</funcprototype>

</funcsynopsis>

<para>

The following structures are used:

<programlisting>

struct rdatainfo {

unsigned int rdi_length; /* length of data */

unsigned char *rdi_data; /* record data */

};

struct rrsetinfo {

unsigned int rri_flags; /* RRSET_VALIDATED... */

unsigned int rri_rdclass; /* class number */

unsigned int rri_rdtype; /* RR type number */

unsigned int rri_ttl; /* time to live */

unsigned int rri_nrdatas; /* size of rdatas array */

unsigned int rri_nsigs; /* size of sigs array */

char *rri_name; /* canonical name */

struct rdatainfo *rri_rdatas; /* individual records */

struct rdatainfo *rri_sigs; /* individual signatures */

};

</programlisting>

</para>

</refsynopsisdiv>

<refsect1>

<title>DESCRIPTION</title>

<para>

<function>lwres_getrrsetbyname()</function>

gets a set of resource records associated with a

<parameter>hostname</parameter>,

<parameter>class</parameter>,

and

<parameter>type</parameter>.

<parameter>hostname</parameter>

is

a pointer a to null-terminated string. The

<parameter>flags</parameter>

field is currently unused and must be zero.

</para>

<para>

After a successful call to

<function>lwres_getrrsetbyname()</function>,

<parameter>*res</parameter>

is a pointer to an

<type>rrsetinfo</type>

structure, containing a list of one or more

<type>rdatainfo</type>

structures containing resource records and potentially another list of

<type>rdatainfo</type>

structures containing SIG resource records

associated with those records.

The members

<constant>rri_rdclass</constant>

and

<constant>rri_rdtype</constant>

are copied from the parameters.

<constant>rri_ttl</constant>

and

<constant>rri_name</constant>

are properties of the obtained rrset.

The resource records contained in

<constant>rri_rdatas</constant>

and

<constant>rri_sigs</constant>

are in uncompressed DNS wire format.

Properties of the rdataset are represented in the

<constant>rri_flags</constant>

bitfield. If the RRSET_VALIDATED bit is set, the data has been DNSSEC

validated and the signatures verified.

</para>

<para>

All of the information returned by

<function>lwres_getrrsetbyname()</function>

is dynamically allocated: the

<constant>rrsetinfo</constant>

and

<constant>rdatainfo</constant>

structures,

and the canonical host name strings pointed to by the

<constant>rrsetinfo</constant>structure.

Memory allocated for the dynamically allocated structures created by

a successful call to

<function>lwres_getrrsetbyname()</function>

is released by

<function>lwres_freerrset()</function>.

<parameter>rrset</parameter>

is a pointer to a

<type>struct rrset</type>

created by a call to

<function>lwres_getrrsetbyname()</function>.

</para>

<para>

</para>

</refsect1>

<refsect1>

<title>RETURN VALUES</title>

<para>

<function>lwres_getrrsetbyname()</function>

returns zero on success or an error code if an error occurs. The defined

error codes are ERRSET_NOMEMORY (memory could not be allocated),

ERRSET_INVAL (a parameter is invalid) and ERRSET_FAIL (other failure).

</para>

</refsect1>

<refsect1>

<title>SEE ALSO</title>

<para>

<citerefentry>

<refentrytitle>lwres</refentrytitle><manvolnum>3</manvolnum>

</citerefentry>.

</para>

</refsect1>

</refentry>