external/bsd/bind/dist/lib/lwres/man/lwres_packet.docbook

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  20
  21 <refentry>
  22
  23   <refentryinfo>
  24     <date>June 18, 2007</date>
  25   </refentryinfo>
  26
  27   <refmeta>
  28     <refentrytitle>lwres_packet</refentrytitle>
  29     <manvolnum>3</manvolnum>
  30     <refmiscinfo>BIND9</refmiscinfo>
  31   </refmeta>
  32
  33   <docinfo>
  34     <copyright>
  35       <year>2004</year>
  36       <year>2005</year>
  37       <year>2007</year>
  38       <year>2014</year>
  39       <holder>Internet Systems Consortium, Inc. ("ISC")</holder>
  40     </copyright>
  41     <copyright>
  42       <year>2000</year>
  43       <year>2001</year>
  44       <holder>Internet Software Consortium.</holder>
  45     </copyright>
  46   </docinfo>
  47
  48   <refnamediv>
  49     <refname>lwres_lwpacket_renderheader</refname>
  50     <refname>lwres_lwpacket_parseheader</refname>
  51     <refpurpose>lightweight resolver packet handling functions</refpurpose>
  52   </refnamediv>
  53   <refsynopsisdiv>
  54     <funcsynopsis>
  55 <funcsynopsisinfo>#include &lt;lwres/lwpacket.h&gt;</funcsynopsisinfo>
  56 <funcprototype>
  57         <funcdef>
  58 lwres_result_t
  59 <function>lwres_lwpacket_renderheader</function></funcdef>
  60         <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
  61         <paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
  62         </funcprototype>
  63 <funcprototype>
  64         <funcdef>
  65 lwres_result_t
  66 <function>lwres_lwpacket_parseheader</function></funcdef>
  67         <paramdef>lwres_buffer_t *<parameter>b</parameter></paramdef>
  68         <paramdef>lwres_lwpacket_t *<parameter>pkt</parameter></paramdef>
  69       </funcprototype>
  70 </funcsynopsis>
  71   </refsynopsisdiv>
  72   <refsect1>
  73     <title>DESCRIPTION</title>
  74     <para>
  75       These functions rely on a
  76       <type>struct lwres_lwpacket</type>
  77       which is defined in
  78       <filename>lwres/lwpacket.h</filename>.
  79     </para>
  80
  81     <para><programlisting>
  82 typedef struct lwres_lwpacket lwres_lwpacket_t;
  83       </programlisting>
  84     </para>
  85     <para><programlisting>
  86 struct lwres_lwpacket {
  87         lwres_uint32_t          length;
  88         lwres_uint16_t          version;
  89         lwres_uint16_t          pktflags;
  90         lwres_uint32_t          serial;
  91         lwres_uint32_t          opcode;
  92         lwres_uint32_t          result;
  93         lwres_uint32_t          recvlength;
  94         lwres_uint16_t          authtype;
  95         lwres_uint16_t          authlength;
  96 };
  97 </programlisting>
  98     </para>
  99
 100     <para>
 101       The elements of this structure are:
 102       <variablelist>
 103         <varlistentry>
 104           <term><constant>length</constant></term>
 105           <listitem>
 106             <para>
 107               the overall packet length, including the entire packet header.
 108               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 109               calls.
 110             </para>
 111           </listitem>
 112         </varlistentry>
 113         <varlistentry>
 114           <term><constant>version</constant></term>
 115           <listitem>
 116             <para>
 117               the header format. There is currently only one format,
 118               <type>LWRES_LWPACKETVERSION_0</type>.
 119
 120               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 121               calls.
 122             </para>
 123           </listitem>
 124         </varlistentry>
 125         <varlistentry>
 126           <term><constant>pktflags</constant></term>
 127           <listitem>
 128             <para>
 129               library-defined flags for this packet: for instance whether the
 130               packet
 131               is a request or a reply. Flag values can be set, but not defined
 132               by
 133               the caller.
 134               This field is filled in by the application wit the exception of
 135               the
 136               LWRES_LWPACKETFLAG_RESPONSE bit, which is set by the library in
 137               the
 138               lwres_gabn_*() and lwres_gnba_*() calls.
 139             </para>
 140           </listitem>
 141         </varlistentry>
 142         <varlistentry>
 143           <term><constant>serial</constant></term>
 144           <listitem>
 145             <para>
 146               is set by the requestor and is returned in all replies. If two
 147               or more
 148               packets from the same source have the same serial number and are
 149               from
 150               the same source, they are assumed to be duplicates and the
 151               latter ones
 152               may be dropped.
 153               This field must be set by the application.
 154             </para>
 155           </listitem>
 156         </varlistentry>
 157         <varlistentry>
 158           <term><constant>opcode</constant></term>
 159           <listitem>
 160             <para>
 161               indicates the operation.
 162               Opcodes between 0x00000000 and 0x03ffffff are
 163               reserved for use by the lightweight resolver library. Opcodes
 164               between
 165               0x04000000 and 0xffffffff are application defined.
 166               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 167               calls.
 168             </para>
 169           </listitem>
 170         </varlistentry>
 171         <varlistentry>
 172           <term><constant>result</constant></term>
 173           <listitem>
 174             <para>
 175               is only valid for replies.
 176               Results between 0x04000000 and 0xffffffff are application
 177               defined.
 178               Results between 0x00000000 and 0x03ffffff are reserved for
 179               library use.
 180               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 181               calls.
 182             </para>
 183           </listitem>
 184         </varlistentry>
 185         <varlistentry>
 186           <term><constant>recvlength</constant></term>
 187           <listitem>
 188             <para>
 189               is the maximum buffer size that the receiver can handle on
 190               requests
 191               and the size of the buffer needed to satisfy a request when the
 192               buffer
 193               is too large for replies.
 194               This field is supplied by the application.
 195             </para>
 196           </listitem>
 197         </varlistentry>
 198         <varlistentry>
 199           <term><constant>authtype</constant></term>
 200           <listitem>
 201             <para>
 202               defines the packet level authentication that is used.
 203               Authorisation types between 0x1000 and 0xffff are application
 204               defined
 205               and types between 0x0000 and 0x0fff are reserved for library
 206               use.
 207               Currently these are not used and must be zero.
 208             </para>
 209           </listitem>
 210         </varlistentry>
 211         <varlistentry>
 212           <term><constant>authlen</constant></term>
 213           <listitem>
 214             <para>
 215               gives the length of the authentication data.
 216               Since packet authentication is currently not used, this must be
 217               zero.
 218             </para>
 219           </listitem>
 220         </varlistentry>
 221       </variablelist>
 222     </para>
 223     <para>
 224       The following opcodes are currently defined:
 225       <variablelist>
 226         <varlistentry>
 227           <term><constant>NOOP</constant></term>
 228           <listitem>
 229             <para>
 230               Success is always returned and the packet contents are echoed.
 231               The lwres_noop_*() functions should be used for this type.
 232             </para>
 233           </listitem>
 234         </varlistentry>
 235         <varlistentry>
 236           <term><constant>GETADDRSBYNAME</constant></term>
 237           <listitem>
 238             <para>
 239               returns all known addresses for a given name.
 240               The lwres_gabn_*() functions should be used for this type.
 241             </para>
 242           </listitem>
 243         </varlistentry>
 244         <varlistentry>
 245           <term><constant>GETNAMEBYADDR</constant></term>
 246           <listitem>
 247             <para>
 248               return the hostname for the given address.
 249               The lwres_gnba_*() functions should be used for this type.
 250             </para>
 251           </listitem>
 252         </varlistentry>
 253       </variablelist>
 254     </para>
 255
 256     <para><function>lwres_lwpacket_renderheader()</function>
 257       transfers the contents of lightweight resolver packet structure
 258       <type>lwres_lwpacket_t</type> <parameter>*pkt</parameter> in
 259       network byte order to the lightweight resolver buffer,
 260       <parameter>*b</parameter>.
 261     </para>
 262
 263     <para><function>lwres_lwpacket_parseheader()</function>
 264       performs the converse operation.  It transfers data in network
 265       byte order from buffer <parameter>*b</parameter> to resolver
 266       packet <parameter>*pkt</parameter>.  The contents of the buffer
 267       <parameter>b</parameter> should correspond to a
 268       <type>lwres_lwpacket_t</type>.
 269     </para>
 270
 271   </refsect1>
 272
 273   <refsect1>
 274     <title>RETURN VALUES</title>
 275     <para>
 276       Successful calls to
 277       <function>lwres_lwpacket_renderheader()</function> and
 278       <function>lwres_lwpacket_parseheader()</function> return
 279       <errorcode>LWRES_R_SUCCESS</errorcode>.  If there is insufficient
 280       space to copy data between the buffer <parameter>*b</parameter> and
 281       lightweight resolver packet <parameter>*pkt</parameter> both
 282       functions
 283       return <errorcode>LWRES_R_UNEXPECTEDEND</errorcode>.
 284     </para>
 285
 286   </refsect1>
 287 </refentry><!--
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 290  - End:
 291 -->