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

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  22
  23 <refentry>
  24
  25 <refentryinfo>
  26 <date>Jun 30, 2000</date>
  27 </refentryinfo>
  28
  29 <refmeta>
  30 <refentrytitle>lwres_packet</refentrytitle>
  31 <manvolnum>3</manvolnum>
  32 <refmiscinfo>BIND9</refmiscinfo>
  33 </refmeta>
  34
  35   <docinfo>
  36     <copyright>
  37       <year>2004</year>
  38       <year>2005</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 *b</paramdef>
  61 <paramdef>lwres_lwpacket_t *pkt</paramdef>
  62 </funcprototype>
  63 <funcprototype>
  64 <funcdef>
  65 lwres_result_t
  66 <function>lwres_lwpacket_parseheader</function></funcdef>
  67 <paramdef>lwres_buffer_t *b</paramdef>
  68 <paramdef>lwres_lwpacket_t *pkt</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
  80 <programlisting>
  81 typedef struct lwres_lwpacket lwres_lwpacket_t;
  82
  83 struct lwres_lwpacket {
  84         lwres_uint32_t          length;
  85         lwres_uint16_t          version;
  86         lwres_uint16_t          pktflags;
  87         lwres_uint32_t          serial;
  88         lwres_uint32_t          opcode;
  89         lwres_uint32_t          result;
  90         lwres_uint32_t          recvlength;
  91         lwres_uint16_t          authtype;
  92         lwres_uint16_t          authlength;
  93 };
  94 </programlisting>
  95 </para>
  96
  97 <para>
  98 The elements of this structure are:
  99 <variablelist>
 100 <varlistentry><term><constant>length</constant></term>
 101 <listitem>
 102 <para>
 103 the overall packet length, including the entire packet header.
 104 This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 105 calls.
 106 </para></listitem></varlistentry>
 107 <varlistentry><term><constant>version</constant></term>
 108 <listitem>
 109 <para>
 110 the header format. There is currently only one format,
 111 <type>LWRES_LWPACKETVERSION_0</type>.
 112
 113 This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 114 calls.
 115 </para></listitem></varlistentry>
 116 <varlistentry><term><constant>pktflags</constant></term>
 117 <listitem>
 118 <para>
 119 library-defined flags for this packet: for instance whether the packet
 120 is a request or a reply. Flag values can be set, but not defined by
 121 the caller.
 122 This field is filled in by the application wit the exception of the
 123 LWRES_LWPACKETFLAG_RESPONSE bit, which is set by the library in the
 124 lwres_gabn_*() and lwres_gnba_*() calls.
 125 </para></listitem></varlistentry>
 126 <varlistentry><term><constant>serial</constant></term>
 127 <listitem>
 128 <para>
 129 is set by the requestor and is returned in all replies. If two or more
 130 packets from the same source have the same serial number and are from
 131 the same source, they are assumed to be duplicates and the latter ones
 132 may be dropped.
 133 This field must be set by the application.
 134 </para></listitem></varlistentry>
 135 <varlistentry><term><constant>opcode</constant></term>
 136 <listitem>
 137 <para>
 138 indicates the operation.
 139 Opcodes between 0x00000000 and 0x03ffffff are
 140 reserved for use by the lightweight resolver library. Opcodes between
 141 0x04000000 and 0xffffffff are application defined.
 142 This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 143 calls.
 144 </para></listitem></varlistentry>
 145 <varlistentry><term><constant>result</constant></term>
 146 <listitem>
 147 <para>
 148 is only valid for replies.
 149 Results between 0x04000000 and 0xffffffff are application defined.
 150 Results between 0x00000000 and 0x03ffffff are reserved for library use.
 151 This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
 152 calls.
 153 </para></listitem></varlistentry>
 154 <varlistentry><term><constant>recvlength</constant></term>
 155 <listitem>
 156 <para>
 157 is the maximum buffer size that the receiver can handle on requests
 158 and the size of the buffer needed to satisfy a request when the buffer
 159 is too large for replies.
 160 This field is supplied by the application.
 161 </para></listitem></varlistentry>
 162 <varlistentry><term><constant>authtype</constant></term>
 163 <listitem>
 164 <para>
 165 defines the packet level authentication that is used.
 166 Authorisation types between 0x1000 and 0xffff are application defined
 167 and types between 0x0000 and 0x0fff are reserved for library use.
 168 Currently these are not used and must be zero.
 169 </para></listitem></varlistentry>
 170 <varlistentry><term><constant>authlen</constant></term>
 171 <listitem>
 172 <para>
 173 gives the length of the authentication data.
 174 Since packet authentication is currently not used, this must be zero.
 175 </para></listitem></varlistentry>
 176 </variablelist>
 177 </para>
 178 <para>
 179 The following opcodes are currently defined:
 180 <variablelist>
 181 <varlistentry><term><constant>NOOP</constant></term>
 182 <listitem>
 183 <para>
 184 Success is always returned and the packet contents are echoed.
 185 The lwres_noop_*() functions should be used for this type.
 186 </para></listitem></varlistentry>
 187 <varlistentry><term><constant>GETADDRSBYNAME</constant></term>
 188 <listitem>
 189 <para>
 190 returns all known addresses for a given name.
 191 The lwres_gabn_*() functions should be used for this type.
 192 </para></listitem></varlistentry>
 193 <varlistentry><term><constant>GETNAMEBYADDR</constant></term>
 194 <listitem>
 195 <para>
 196 return the hostname for the given address.
 197 The lwres_gnba_*() functions should be used for this type.
 198 </para></listitem></varlistentry>
 199 </variablelist>
 200 </para>
 201
 202 <para>
 203 <function>lwres_lwpacket_renderheader()</function> transfers the
 204 contents of lightweight resolver packet structure
 205 <type>lwres_lwpacket_t</type> <parameter>*pkt</parameter> in network
 206 byte order to the lightweight resolver buffer,
 207 <parameter>*b</parameter>.
 208 </para>
 209
 210 <para>
 211 <function>lwres_lwpacket_parseheader()</function> performs the
 212 converse operation.  It transfers data in network byte order from
 213 buffer <parameter>*b</parameter> to resolver packet
 214 <parameter>*pkt</parameter>.  The contents of the buffer
 215 <parameter>b</parameter> should correspond to a
 216 <type>lwres_lwpacket_t</type>.
 217 </para>
 218
 219 </refsect1>
 220
 221 <refsect1>
 222 <title>RETURN VALUES</title>
 223 <para> Successful calls to
 224 <function>lwres_lwpacket_renderheader()</function> and
 225 <function>lwres_lwpacket_parseheader()</function> return
 226 <errorcode>LWRES_R_SUCCESS</errorcode>.  If there is insufficient
 227 space to copy data between the buffer <parameter>*b</parameter> and
 228 lightweight resolver packet <parameter>*pkt</parameter> both functions
 229 return <errorcode>LWRES_R_UNEXPECTEDEND</errorcode>.
 230 </para>
 231
 232 </refsect1>
 233 </refentry>