lwres_getrrsetbyname.docbook [plain text]
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<refentry>
<refentryinfo>
<date>Oct 18, 2000</date>
</refentryinfo>
<refmeta>
<refentrytitle>lwres_getrrsetbyname</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>BIND9</refmiscinfo>
</refmeta>
<docinfo>
<copyright>
<year>2004</year>
<year>2005</year>
<holder>Internet Systems Consortium, Inc. ("ISC")</holder>
</copyright>
<copyright>
<year>2000</year>
<year>2001</year>
<holder>Internet Software Consortium.</holder>
</copyright>
</docinfo>
<refnamediv>
<refname>lwres_getrrsetbyname</refname>
<refname>lwres_freerrset</refname>
<refpurpose>retrieve DNS records</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <lwres/netdb.h></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, and one of the following error
codes if an error occurred:
<variablelist>
<varlistentry><term><constant>ERRSET_NONAME</constant></term>
<listitem><para>
the name does not exist
</para></listitem></varlistentry>
<varlistentry><term><constant>ERRSET_NODATA</constant></term>
<listitem><para>
the name exists, but does not have data of the desired type
</para></listitem></varlistentry>
<varlistentry><term><constant>ERRSET_NOMEMORY</constant></term>
<listitem><para>
memory could not be allocated
</para></listitem></varlistentry>
<varlistentry><term><constant>ERRSET_INVAL</constant></term>
<listitem><para>
a parameter is invalid
</para></listitem></varlistentry>
<varlistentry><term><constant>ERRSET_FAIL</constant></term>
<listitem><para>
other failure
</para></listitem></varlistentry>
<varlistentry><term><constant></constant></term>
<listitem><para>
</para></listitem></varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1>
<title>SEE ALSO</title>
<para>
<citerefentry>
<refentrytitle>lwres</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>.
</para>
</refsect1>
</refentry>