contrib/bind9/lib/lwres/man/lwres_gnba.docbook

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  21 <!-- $Id$ -->
  22 <refentry>
  23
  24   <refentryinfo>
  25     <date>Jun 30, 2000</date>
  26   </refentryinfo>
  27
  28   <refmeta>
  29     <refentrytitle>lwres_gnba</refentrytitle>
  30     <manvolnum>3</manvolnum>
  31     <refmiscinfo>BIND9</refmiscinfo>
  32   </refmeta>
  33
  34   <docinfo>
  35     <copyright>
  36       <year>2004</year>
  37       <year>2005</year>
  38       <year>2007</year>
  39       <year>2012</year>
  40       <holder>Internet Systems Consortium, Inc. ("ISC")</holder>
  41     </copyright>
  42     <copyright>
  43       <year>2000</year>
  44       <year>2001</year>
  45       <holder>Internet Software Consortium.</holder>
  46     </copyright>
  47   </docinfo>
  48
  49   <refnamediv>
  50     <refname>lwres_gnbarequest_render</refname>
  51     <refname>lwres_gnbaresponse_render</refname>
  52     <refname>lwres_gnbarequest_parse</refname>
  53     <refname>lwres_gnbaresponse_parse</refname>
  54     <refname>lwres_gnbaresponse_free</refname>
  55     <refname>lwres_gnbarequest_free</refname>
  56     <refpurpose>lightweight resolver getnamebyaddress message handling</refpurpose>
  57   </refnamediv>
  58
  59   <refsynopsisdiv>
  60
  61     <funcsynopsis>
  62 <funcsynopsisinfo>
  63 #include &lt;lwres/lwres.h&gt;
  64 </funcsynopsisinfo>
  65
  66 <funcprototype>
  67         <funcdef>
  68 lwres_result_t
  69 <function>lwres_gnbarequest_render</function>
  70 </funcdef>
  71         <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
  72         <paramdef>lwres_gnbarequest_t *<parameter>req</parameter></paramdef>
  73         <paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
  74         <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
  75         </funcprototype>
  76
  77 <funcprototype>
  78         <funcdef>
  79 lwres_result_t
  80 <function>lwres_gnbaresponse_render</function>
  81 </funcdef>
  82         <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
  83         <paramdef>lwres_gnbaresponse_t *<parameter>req</parameter></paramdef>
  84         <paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
  85         <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
  86         </funcprototype>
  87 <funcprototype>
  88         <funcdef>
  89 lwres_result_t
  90 <function>lwres_gnbarequest_parse</function></funcdef>
  91         <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
  92         <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
  93         <paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
  94         <paramdef>lwres_gnbarequest_t **<parameter>structp</parameter></paramdef>
  95         </funcprototype>
  96 <funcprototype>
  97         <funcdef>
  98 lwres_result_t
  99 <function>lwres_gnbaresponse_parse</function></funcdef>
 100         <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
 101         <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
 102         <paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
 103         <paramdef>lwres_gnbaresponse_t **<parameter>structp</parameter></paramdef>
 104         </funcprototype>
 105
 106 <funcprototype>
 107         <funcdef>
 108 void
 109 <function>lwres_gnbaresponse_free</function>
 110 </funcdef>
 111         <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
 112         <paramdef>lwres_gnbaresponse_t **<parameter>structp</parameter></paramdef>
 113         </funcprototype>
 114 <funcprototype>
 115         <funcdef>
 116 void
 117 <function>lwres_gnbarequest_free</function></funcdef>
 118         <paramdef>lwres_context_t *<parameter>ctx</parameter></paramdef>
 119         <paramdef>lwres_gnbarequest_t **<parameter>structp</parameter></paramdef>
 120       </funcprototype>
 121 </funcsynopsis>
 122
 123   </refsynopsisdiv>
 124
 125   <refsect1>
 126     <title>DESCRIPTION</title>
 127     <para>
 128       These are low-level routines for creating and parsing
 129       lightweight resolver address-to-name lookup request and
 130       response messages.
 131     </para>
 132     <para>
 133       There are four main functions for the getnamebyaddr opcode.
 134       One render function converts a getnamebyaddr request structure &mdash;
 135       <type>lwres_gnbarequest_t</type> &mdash;
 136       to the lightweight resolver's canonical format.
 137       It is complemented by a parse function that converts a packet in this
 138       canonical format to a getnamebyaddr request structure.
 139       Another render function converts the getnamebyaddr response structure
 140       &mdash;
 141       <type>lwres_gnbaresponse_t</type>
 142       to the canonical format.
 143       This is complemented by a parse function which converts a packet in
 144       canonical format to a getnamebyaddr response structure.
 145     </para>
 146     <para>
 147       These structures are defined in
 148       <filename>lwres/lwres.h</filename>.
 149       They are shown below.
 150     </para>
 151     <para><programlisting>
 152 #define LWRES_OPCODE_GETNAMEBYADDR      0x00010002U
 153 </programlisting>
 154     </para>
 155     <para><programlisting>
 156 typedef struct {
 157         lwres_uint32_t  flags;
 158         lwres_addr_t    addr;
 159 } lwres_gnbarequest_t;
 160 </programlisting>
 161     </para>
 162     <para><programlisting>
 163 typedef struct {
 164         lwres_uint32_t  flags;
 165         lwres_uint16_t  naliases;
 166         char           *realname;
 167         char          **aliases;
 168         lwres_uint16_t  realnamelen;
 169         lwres_uint16_t *aliaslen;
 170         void           *base;
 171         size_t          baselen;
 172 } lwres_gnbaresponse_t;
 173 </programlisting>
 174     </para>
 175
 176     <para><function>lwres_gnbarequest_render()</function>
 177       uses resolver context <varname>ctx</varname> to convert
 178       getnamebyaddr request structure <varname>req</varname> to
 179       canonical format.  The packet header structure
 180       <varname>pkt</varname> is initialised and transferred to buffer
 181       <varname>b</varname>.  The contents of <varname>*req</varname>
 182       are then appended to the buffer in canonical format.
 183       <function>lwres_gnbaresponse_render()</function> performs the
 184       same task, except it converts a getnamebyaddr response structure
 185       <type>lwres_gnbaresponse_t</type> to the lightweight resolver's
 186       canonical format.
 187     </para>
 188
 189     <para><function>lwres_gnbarequest_parse()</function>
 190       uses context <varname>ctx</varname> to convert the contents of
 191       packet <varname>pkt</varname> to a
 192       <type>lwres_gnbarequest_t</type> structure.  Buffer
 193       <varname>b</varname> provides space to be used for storing this
 194       structure.  When the function succeeds, the resulting
 195       <type>lwres_gnbarequest_t</type> is made available through
 196       <varname>*structp</varname>.
 197       <function>lwres_gnbaresponse_parse()</function> offers the same
 198       semantics as <function>lwres_gnbarequest_parse()</function>
 199       except it yields a <type>lwres_gnbaresponse_t</type> structure.
 200     </para>
 201
 202     <para><function>lwres_gnbaresponse_free()</function>
 203       and <function>lwres_gnbarequest_free()</function> release the
 204       memory in resolver context <varname>ctx</varname> that was
 205       allocated to the <type>lwres_gnbaresponse_t</type> or
 206       <type>lwres_gnbarequest_t</type> structures referenced via
 207       <varname>structp</varname>.  Any memory associated with
 208       ancillary buffers and strings for those structures is also
 209       discarded.
 210     </para>
 211   </refsect1>
 212
 213   <refsect1>
 214     <title>RETURN VALUES</title>
 215     <para>
 216       The getnamebyaddr opcode functions
 217       <function>lwres_gnbarequest_render()</function>,
 218       <function>lwres_gnbaresponse_render()</function>
 219       <function>lwres_gnbarequest_parse()</function>
 220       and
 221       <function>lwres_gnbaresponse_parse()</function>
 222       all return
 223       <errorcode>LWRES_R_SUCCESS</errorcode>
 224       on success.
 225       They return
 226       <errorcode>LWRES_R_NOMEMORY</errorcode>
 227       if memory allocation fails.
 228       <errorcode>LWRES_R_UNEXPECTEDEND</errorcode>
 229       is returned if the available space in the buffer
 230       <varname>b</varname>
 231       is too small to accommodate the packet header or the
 232       <type>lwres_gnbarequest_t</type>
 233       and
 234       <type>lwres_gnbaresponse_t</type>
 235       structures.
 236       <function>lwres_gnbarequest_parse()</function>
 237       and
 238       <function>lwres_gnbaresponse_parse()</function>
 239       will return
 240       <errorcode>LWRES_R_UNEXPECTEDEND</errorcode>
 241       if the buffer is not empty after decoding the received packet.
 242       These functions will return
 243       <errorcode>LWRES_R_FAILURE</errorcode>
 244       if
 245       <structfield>pktflags</structfield>
 246       in the packet header structure
 247       <type>lwres_lwpacket_t</type>
 248       indicate that the packet is not a response to an earlier query.
 249     </para>
 250   </refsect1>
 251   <refsect1>
 252     <title>SEE ALSO</title>
 253     <para><citerefentry>
 254         <refentrytitle>lwres_packet</refentrytitle><manvolnum>3</manvolnum>
 255       </citerefentry>.
 256     </para>
 257   </refsect1>
 258 </refentry><!--
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