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

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  21 <title>lwres_packet</title>
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  24 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en">
  25 <a name="id2476275"></a><div class="titlepage"></div>
  26 <div class="refnamediv">
  27 <h2>Name</h2>
  28 <p>lwres_lwpacket_renderheader, lwres_lwpacket_parseheader &#8212; lightweight resolver packet handling functions</p>
  29 </div>
  30 <div class="refsynopsisdiv">
  31 <h2>Synopsis</h2>
  32 <div class="funcsynopsis">
  33 <pre class="funcsynopsisinfo">#include &lt;lwres/lwpacket.h&gt;</pre>
  34 <table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
  35 <tr>
  36 <td><code class="funcdef">
  37 lwres_result_t
  38 <b class="fsfunc">lwres_lwpacket_renderheader</b>(</code></td>
  39 <td>lwres_buffer_t * </td>
  40 <td>
  41 <var class="pdparam">b</var>, </td>
  42 </tr>
  43 <tr>
  44 <td> </td>
  45 <td>lwres_lwpacket_t * </td>
  46 <td>
  47 <var class="pdparam">pkt</var><code>)</code>;</td>
  48 </tr>
  49 </table>
  50 <table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
  51 <tr>
  52 <td><code class="funcdef">
  53 lwres_result_t
  54 <b class="fsfunc">lwres_lwpacket_parseheader</b>(</code></td>
  55 <td>lwres_buffer_t * </td>
  56 <td>
  57 <var class="pdparam">b</var>, </td>
  58 </tr>
  59 <tr>
  60 <td> </td>
  61 <td>lwres_lwpacket_t * </td>
  62 <td>
  63 <var class="pdparam">pkt</var><code>)</code>;</td>
  64 </tr>
  65 </table>
  66 </div>
  67 </div>
  68 <div class="refsect1" lang="en">
  69 <a name="id2543399"></a><h2>DESCRIPTION</h2>
  70 <p>
  71       These functions rely on a
  72       <span class="type">struct lwres_lwpacket</span>
  73       which is defined in
  74       <code class="filename">lwres/lwpacket.h</code>.
  75     </p>
  76 <pre class="programlisting">
  77 typedef struct lwres_lwpacket lwres_lwpacket_t;
  78       </pre>
  79 <p>
  80     </p>
  81 <pre class="programlisting">
  82 struct lwres_lwpacket {
  83         lwres_uint32_t          length;
  84         lwres_uint16_t          version;
  85         lwres_uint16_t          pktflags;
  86         lwres_uint32_t          serial;
  87         lwres_uint32_t          opcode;
  88         lwres_uint32_t          result;
  89         lwres_uint32_t          recvlength;
  90         lwres_uint16_t          authtype;
  91         lwres_uint16_t          authlength;
  92 };
  93 </pre>
  94 <p>
  95     </p>
  96 <p>
  97       The elements of this structure are:
  98       </p>
  99 <div class="variablelist"><dl>
 100 <dt><span class="term"><code class="constant">length</code></span></dt>
 101 <dd><p>
 102               the overall packet length, including the entire packet header.
 103               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 104               calls.
 105             </p></dd>
 106 <dt><span class="term"><code class="constant">version</code></span></dt>
 107 <dd><p>
 108               the header format. There is currently only one format,
 109               <span class="type">LWRES_LWPACKETVERSION_0</span>.
 110
 111               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 112               calls.
 113             </p></dd>
 114 <dt><span class="term"><code class="constant">pktflags</code></span></dt>
 115 <dd><p>
 116               library-defined flags for this packet: for instance whether the
 117               packet
 118               is a request or a reply. Flag values can be set, but not defined
 119               by
 120               the caller.
 121               This field is filled in by the application wit the exception of
 122               the
 123               LWRES_LWPACKETFLAG_RESPONSE bit, which is set by the library in
 124               the
 125               lwres_gabn_*() and lwres_gnba_*() calls.
 126             </p></dd>
 127 <dt><span class="term"><code class="constant">serial</code></span></dt>
 128 <dd><p>
 129               is set by the requestor and is returned in all replies. If two
 130               or more
 131               packets from the same source have the same serial number and are
 132               from
 133               the same source, they are assumed to be duplicates and the
 134               latter ones
 135               may be dropped.
 136               This field must be set by the application.
 137             </p></dd>
 138 <dt><span class="term"><code class="constant">opcode</code></span></dt>
 139 <dd><p>
 140               indicates the operation.
 141               Opcodes between 0x00000000 and 0x03ffffff are
 142               reserved for use by the lightweight resolver library. Opcodes
 143               between
 144               0x04000000 and 0xffffffff are application defined.
 145               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 146               calls.
 147             </p></dd>
 148 <dt><span class="term"><code class="constant">result</code></span></dt>
 149 <dd><p>
 150               is only valid for replies.
 151               Results between 0x04000000 and 0xffffffff are application
 152               defined.
 153               Results between 0x00000000 and 0x03ffffff are reserved for
 154               library use.
 155               This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 156               calls.
 157             </p></dd>
 158 <dt><span class="term"><code class="constant">recvlength</code></span></dt>
 159 <dd><p>
 160               is the maximum buffer size that the receiver can handle on
 161               requests
 162               and the size of the buffer needed to satisfy a request when the
 163               buffer
 164               is too large for replies.
 165               This field is supplied by the application.
 166             </p></dd>
 167 <dt><span class="term"><code class="constant">authtype</code></span></dt>
 168 <dd><p>
 169               defines the packet level authentication that is used.
 170               Authorisation types between 0x1000 and 0xffff are application
 171               defined
 172               and types between 0x0000 and 0x0fff are reserved for library
 173               use.
 174               Currently these are not used and must be zero.
 175             </p></dd>
 176 <dt><span class="term"><code class="constant">authlen</code></span></dt>
 177 <dd><p>
 178               gives the length of the authentication data.
 179               Since packet authentication is currently not used, this must be
 180               zero.
 181             </p></dd>
 182 </dl></div>
 183 <p>
 184     </p>
 185 <p>
 186       The following opcodes are currently defined:
 187       </p>
 188 <div class="variablelist"><dl>
 189 <dt><span class="term"><code class="constant">NOOP</code></span></dt>
 190 <dd><p>
 191               Success is always returned and the packet contents are echoed.
 192               The lwres_noop_*() functions should be used for this type.
 193             </p></dd>
 194 <dt><span class="term"><code class="constant">GETADDRSBYNAME</code></span></dt>
 195 <dd><p>
 196               returns all known addresses for a given name.
 197               The lwres_gabn_*() functions should be used for this type.
 198             </p></dd>
 199 <dt><span class="term"><code class="constant">GETNAMEBYADDR</code></span></dt>
 200 <dd><p>
 201               return the hostname for the given address.
 202               The lwres_gnba_*() functions should be used for this type.
 203             </p></dd>
 204 </dl></div>
 205 <p>
 206     </p>
 207 <p><code class="function">lwres_lwpacket_renderheader()</code>
 208       transfers the contents of lightweight resolver packet structure
 209       <span class="type">lwres_lwpacket_t</span> <em class="parameter"><code>*pkt</code></em> in
 210       network byte order to the lightweight resolver buffer,
 211       <em class="parameter"><code>*b</code></em>.
 212     </p>
 213 <p><code class="function">lwres_lwpacket_parseheader()</code>
 214       performs the converse operation.  It transfers data in network
 215       byte order from buffer <em class="parameter"><code>*b</code></em> to resolver
 216       packet <em class="parameter"><code>*pkt</code></em>.  The contents of the buffer
 217       <em class="parameter"><code>b</code></em> should correspond to a
 218       <span class="type">lwres_lwpacket_t</span>.
 219     </p>
 220 </div>
 221 <div class="refsect1" lang="en">
 222 <a name="id2543716"></a><h2>RETURN VALUES</h2>
 223 <p>
 224       Successful calls to
 225       <code class="function">lwres_lwpacket_renderheader()</code> and
 226       <code class="function">lwres_lwpacket_parseheader()</code> return
 227       <span class="errorcode">LWRES_R_SUCCESS</span>.  If there is insufficient
 228       space to copy data between the buffer <em class="parameter"><code>*b</code></em> and
 229       lightweight resolver packet <em class="parameter"><code>*pkt</code></em> both
 230       functions
 231       return <span class="errorcode">LWRES_R_UNEXPECTEDEND</span>.
 232     </p>
 233 </div>
 234 </div></body>
 235 </html>