contrib/bind9/lib/lwres/man/lwres_packet.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_packet</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_lwpacket_renderheader</refname>
  51     <refname>lwres_lwpacket_parseheader</refname>
  52     <refpurpose>lightweight resolver packet handling functions</refpurpose>
  53   </refnamediv>
  54   <refsynopsisdiv>
  55     <funcsynopsis>
  56 <funcsynopsisinfo>#include &lt;lwres/lwpacket.h&gt;</funcsynopsisinfo>
  57 <funcprototype>
  58         <funcdef>
  59 lwres_result_t
  60 <function>lwres_lwpacket_renderheader</function></funcdef>
  61         <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
  62         <paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
  63         </funcprototype>
  64 <funcprototype>
  65         <funcdef>
  66 lwres_result_t
  67 <function>lwres_lwpacket_parseheader</function></funcdef>
  68         <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
  69         <paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
  70       </funcprototype>
  71 </funcsynopsis>
  72   </refsynopsisdiv>
  73   <refsect1>
  74     <title>DESCRIPTION</title>
  75     <para>
  76       These functions rely on a
  77       <type>struct lwres_lwpacket</type>
  78       which is defined in
  79       <filename>lwres/lwpacket.h</filename>.
  80     </para>
  81
  82     <para><programlisting>
  83 typedef struct lwres_lwpacket lwres_lwpacket_t;
  84       </programlisting>
  85     </para>
  86     <para><programlisting>
  87 struct lwres_lwpacket {
  88         lwres_uint32_t          length;
  89         lwres_uint16_t          version;
  90         lwres_uint16_t          pktflags;
  91         lwres_uint32_t          serial;
  92         lwres_uint32_t          opcode;
  93         lwres_uint32_t          result;
  94         lwres_uint32_t          recvlength;
  95         lwres_uint16_t          authtype;
  96         lwres_uint16_t          authlength;
  97 };
  98 </programlisting>
  99     </para>
 100
 101     <para>
 102       The elements of this structure are:
 103       <variablelist>
 104         <varlistentry>
 105           <term><constant>length</constant></term>
 106           <listitem>
 107             <para>
 108               the overall packet length, including the entire packet header.
 109               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 110               calls.
 111             </para>
 112           </listitem>
 113         </varlistentry>
 114         <varlistentry>
 115           <term><constant>version</constant></term>
 116           <listitem>
 117             <para>
 118               the header format. There is currently only one format,
 119               <type>LWRES_LWPACKETVERSION_0</type>.
 120
 121               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 122               calls.
 123             </para>
 124           </listitem>
 125         </varlistentry>
 126         <varlistentry>
 127           <term><constant>pktflags</constant></term>
 128           <listitem>
 129             <para>
 130               library-defined flags for this packet: for instance whether the
 131               packet
 132               is a request or a reply. Flag values can be set, but not defined
 133               by
 134               the caller.
 135               This field is filled in by the application wit the exception of
 136               the
 137               LWRES_LWPACKETFLAG_RESPONSE bit, which is set by the library in
 138               the
 139               lwres_gabn_*() and lwres_gnba_*() calls.
 140             </para>
 141           </listitem>
 142         </varlistentry>
 143         <varlistentry>
 144           <term><constant>serial</constant></term>
 145           <listitem>
 146             <para>
 147               is set by the requestor and is returned in all replies. If two
 148               or more
 149               packets from the same source have the same serial number and are
 150               from
 151               the same source, they are assumed to be duplicates and the
 152               latter ones
 153               may be dropped.
 154               This field must be set by the application.
 155             </para>
 156           </listitem>
 157         </varlistentry>
 158         <varlistentry>
 159           <term><constant>opcode</constant></term>
 160           <listitem>
 161             <para>
 162               indicates the operation.
 163               Opcodes between 0x00000000 and 0x03ffffff are
 164               reserved for use by the lightweight resolver library. Opcodes
 165               between
 166               0x04000000 and 0xffffffff are application defined.
 167               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 168               calls.
 169             </para>
 170           </listitem>
 171         </varlistentry>
 172         <varlistentry>
 173           <term><constant>result</constant></term>
 174           <listitem>
 175             <para>
 176               is only valid for replies.
 177               Results between 0x04000000 and 0xffffffff are application
 178               defined.
 179               Results between 0x00000000 and 0x03ffffff are reserved for
 180               library use.
 181               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 182               calls.
 183             </para>
 184           </listitem>
 185         </varlistentry>
 186         <varlistentry>
 187           <term><constant>recvlength</constant></term>
 188           <listitem>
 189             <para>
 190               is the maximum buffer size that the receiver can handle on
 191               requests
 192               and the size of the buffer needed to satisfy a request when the
 193               buffer
 194               is too large for replies.
 195               This field is supplied by the application.
 196             </para>
 197           </listitem>
 198         </varlistentry>
 199         <varlistentry>
 200           <term><constant>authtype</constant></term>
 201           <listitem>
 202             <para>
 203               defines the packet level authentication that is used.
 204               Authorisation types between 0x1000 and 0xffff are application
 205               defined
 206               and types between 0x0000 and 0x0fff are reserved for library
 207               use.
 208               Currently these are not used and must be zero.
 209             </para>
 210           </listitem>
 211         </varlistentry>
 212         <varlistentry>
 213           <term><constant>authlen</constant></term>
 214           <listitem>
 215             <para>
 216               gives the length of the authentication data.
 217               Since packet authentication is currently not used, this must be
 218               zero.
 219             </para>
 220           </listitem>
 221         </varlistentry>
 222       </variablelist>
 223     </para>
 224     <para>
 225       The following opcodes are currently defined:
 226       <variablelist>
 227         <varlistentry>
 228           <term><constant>NOOP</constant></term>
 229           <listitem>
 230             <para>
 231               Success is always returned and the packet contents are echoed.
 232               The lwres_noop_*() functions should be used for this type.
 233             </para>
 234           </listitem>
 235         </varlistentry>
 236         <varlistentry>
 237           <term><constant>GETADDRSBYNAME</constant></term>
 238           <listitem>
 239             <para>
 240               returns all known addresses for a given name.
 241               The lwres_gabn_*() functions should be used for this type.
 242             </para>
 243           </listitem>
 244         </varlistentry>
 245         <varlistentry>
 246           <term><constant>GETNAMEBYADDR</constant></term>
 247           <listitem>
 248             <para>
 249               return the hostname for the given address.
 250               The lwres_gnba_*() functions should be used for this type.
 251             </para>
 252           </listitem>
 253         </varlistentry>
 254       </variablelist>
 255     </para>
 256
 257     <para><function>lwres_lwpacket_renderheader()</function>
 258       transfers the contents of lightweight resolver packet structure
 259       <type>lwres_lwpacket_t</type> <parameter>*pkt</parameter> in
 260       network byte order to the lightweight resolver buffer,
 261       <parameter>*b</parameter>.
 262     </para>
 263
 264     <para><function>lwres_lwpacket_parseheader()</function>
 265       performs the converse operation.  It transfers data in network
 266       byte order from buffer <parameter>*b</parameter> to resolver
 267       packet <parameter>*pkt</parameter>.  The contents of the buffer
 268       <parameter>b</parameter> should correspond to a
 269       <type>lwres_lwpacket_t</type>.
 270     </para>
 271
 272   </refsect1>
 273
 274   <refsect1>
 275     <title>RETURN VALUES</title>
 276     <para>
 277       Successful calls to
 278       <function>lwres_lwpacket_renderheader()</function> and
 279       <function>lwres_lwpacket_parseheader()</function> return
 280       <errorcode>LWRES_R_SUCCESS</errorcode>.  If there is insufficient
 281       space to copy data between the buffer <parameter>*b</parameter> and
 282       lightweight resolver packet <parameter>*pkt</parameter> both
 283       functions
 284       return <errorcode>LWRES_R_UNEXPECTEDEND</errorcode>.
 285     </para>
 286
 287   </refsect1>
 288 </refentry><!--
 289  - Local variables:
 290  - mode: sgml
 291  - End:
 292 -->