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843e19887f64dde75055cf8842fc4db2171eff45johnlev<title>Appendix�D.�BIND 9 DNS Library Support</title>
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843e19887f64dde75055cf8842fc4db2171eff45johnlev<tr><th colspan="3" align="center">Appendix�D.�BIND 9 DNS Library Support</th></tr>
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a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab<a name="Bv9ARM.ch12"></a>Appendix�D.�BIND 9 DNS Library Support</h2></div></div></div>
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab<dt><span class="sect1"><a href="Bv9ARM.ch12.html#bind9.library">BIND 9 DNS Library Support</a></span></dt>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<dt><span class="sect2"><a href="Bv9ARM.ch12.html#id2612035">Prerequisite</a></span></dt>
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab<dt><span class="sect2"><a href="Bv9ARM.ch12.html#id2612044">Compilation</a></span></dt>
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab<dt><span class="sect2"><a href="Bv9ARM.ch12.html#id2612069">Installation</a></span></dt>
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab<dt><span class="sect2"><a href="Bv9ARM.ch12.html#id2612987">Known Defects/Restrictions</a></span></dt>
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab<dt><span class="sect2"><a href="Bv9ARM.ch12.html#id2613064">The dns.conf File</a></span></dt>
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab<dt><span class="sect2"><a href="Bv9ARM.ch12.html#id2613091">Sample Applications</a></span></dt>
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab<dt><span class="sect2"><a href="Bv9ARM.ch12.html#id2614132">Library References</a></span></dt>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<div class="titlepage"><div><div><h2 class="title" style="clear: both">
843e19887f64dde75055cf8842fc4db2171eff45johnlev<a name="bind9.library"></a>BIND 9 DNS Library Support</h2></div></div></div>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<p>This version of BIND 9 "exports" its internal libraries so
843e19887f64dde75055cf8842fc4db2171eff45johnlev that they can be used by third-party applications more easily (we
843e19887f64dde75055cf8842fc4db2171eff45johnlev call them "export" libraries in this document). In addition to
843e19887f64dde75055cf8842fc4db2171eff45johnlev all major DNS-related APIs BIND 9 is currently using, the export
843e19887f64dde75055cf8842fc4db2171eff45johnlev libraries provide the following features:</p>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<li><p>The newly created "DNS client" module. This is a higher
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab level API that provides an interface to name resolution,
843e19887f64dde75055cf8842fc4db2171eff45johnlev single DNS transaction with a particular server, and dynamic
843e19887f64dde75055cf8842fc4db2171eff45johnlev update. Regarding name resolution, it supports advanced
843e19887f64dde75055cf8842fc4db2171eff45johnlev features such as DNSSEC validation and caching. This module
843e19887f64dde75055cf8842fc4db2171eff45johnlev supports both synchronous and asynchronous mode.</p></li>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<li><p>The new "IRS" (Information Retrieval System) library.
843e19887f64dde75055cf8842fc4db2171eff45johnlev It provides an interface to parse the traditional resolv.conf
843e19887f64dde75055cf8842fc4db2171eff45johnlev file and more advanced, DNS-specific configuration file for
843e19887f64dde75055cf8842fc4db2171eff45johnlev the rest of this package (see the description for the
843e19887f64dde75055cf8842fc4db2171eff45johnlev<li><p>As part of the IRS library, newly implemented standard
843e19887f64dde75055cf8842fc4db2171eff45johnlev address-name mapping functions, getaddrinfo() and
843e19887f64dde75055cf8842fc4db2171eff45johnlev getnameinfo(), are provided. They use the DNSSEC-aware
843e19887f64dde75055cf8842fc4db2171eff45johnlev validating resolver backend, and could use other advanced
843e19887f64dde75055cf8842fc4db2171eff45johnlev features of the BIND 9 libraries such as caching. The
843e19887f64dde75055cf8842fc4db2171eff45johnlev getaddrinfo() function resolves both A and AAAA RRs
843e19887f64dde75055cf8842fc4db2171eff45johnlev concurrently (when the address family is unspecified).</p></li>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<li><p>An experimental framework to support other event
843e19887f64dde75055cf8842fc4db2171eff45johnlev libraries than BIND 9's internal event task system.</p></li>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<a name="id2612035"></a>Prerequisite</h3></div></div></div>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<p>GNU make is required to build the export libraries (other
843e19887f64dde75055cf8842fc4db2171eff45johnlev part of BIND 9 can still be built with other types of make). In
843e19887f64dde75055cf8842fc4db2171eff45johnlev the reminder of this document, "make" means GNU make. Note that
843e19887f64dde75055cf8842fc4db2171eff45johnlev in some platforms you may need to invoke a different command name
843e19887f64dde75055cf8842fc4db2171eff45johnlev than "make" (e.g. "gmake") to indicate it's GNU make.</p>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<a name="id2612044"></a>Compilation</h3></div></div></div>
843e19887f64dde75055cf8842fc4db2171eff45johnlev$ <strong class="userinput"><code>/configure --enable-exportlib <em class="replaceable"><code>[other flags]</code></em></code></strong>
843e19887f64dde75055cf8842fc4db2171eff45johnlev$ <strong class="userinput"><code>make</code></strong>
843e19887f64dde75055cf8842fc4db2171eff45johnlev This will create (in addition to usual BIND 9 programs) and a
843e19887f64dde75055cf8842fc4db2171eff45johnlev separate set of libraries under the lib/export directory. For
843e19887f64dde75055cf8842fc4db2171eff45johnlev example, <code class="filename">lib/export/dns/libdns.a</code> is the archive file of the
843e19887f64dde75055cf8842fc4db2171eff45johnlev export version of the BIND 9 DNS library. Sample application
843e19887f64dde75055cf8842fc4db2171eff45johnlev programs using the libraries will also be built under the
843e19887f64dde75055cf8842fc4db2171eff45johnlev<a name="id2612069"></a>Installation</h3></div></div></div>
843e19887f64dde75055cf8842fc4db2171eff45johnlev$ <strong class="userinput"><code>cd lib/export</code></strong>
843e19887f64dde75055cf8842fc4db2171eff45johnlev$ <strong class="userinput"><code>make install</code></strong>
843e19887f64dde75055cf8842fc4db2171eff45johnlev This will install library object files under the directory
843e19887f64dde75055cf8842fc4db2171eff45johnlev specified by the --with-export-libdir configure option (default:
843e19887f64dde75055cf8842fc4db2171eff45johnlev EPREFIX/lib/bind9), and header files under the directory
843e19887f64dde75055cf8842fc4db2171eff45johnlev specified by the --with-export-includedir configure option
843e19887f64dde75055cf8842fc4db2171eff45johnlev Root privilege is normally required.
843e19887f64dde75055cf8842fc4db2171eff45johnlev "<span><strong class="command">make install</strong></span>" at the top directory will do the
843e19887f64dde75055cf8842fc4db2171eff45johnlev To see how to build your own
843e19887f64dde75055cf8842fc4db2171eff45johnlev application after the installation, see
843e19887f64dde75055cf8842fc4db2171eff45johnlev <code class="filename">lib/export/samples/Makefile-postinstall.in</code>.</p>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<a name="id2612987"></a>Known Defects/Restrictions</h3></div></div></div>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<li><p>Currently, win32 is not supported for the export
843e19887f64dde75055cf8842fc4db2171eff45johnlev library. (Normal BIND 9 application can be built as
843e19887f64dde75055cf8842fc4db2171eff45johnlev<p>The "fixed" RRset order is not (currently) supported in
843e19887f64dde75055cf8842fc4db2171eff45johnlev the export library. If you want to use "fixed" RRset order
843e19887f64dde75055cf8842fc4db2171eff45johnlev for, e.g. <span><strong class="command">named</strong></span> while still building the
843e19887f64dde75055cf8842fc4db2171eff45johnlev export library even without the fixed order support, build
843e19887f64dde75055cf8842fc4db2171eff45johnlev them separately:
843e19887f64dde75055cf8842fc4db2171eff45johnlev$ <strong class="userinput"><code>/configure --enable-fixed-rrset <em class="replaceable"><code>[other flags, but not --enable-exportlib]</code></em></code></strong>
843e19887f64dde75055cf8842fc4db2171eff45johnlev$ <strong class="userinput"><code>make</code></strong>
843e19887f64dde75055cf8842fc4db2171eff45johnlev$ <strong class="userinput"><code>/configure --enable-exportlib <em class="replaceable"><code>[other flags, but not --enable-fixed-rrset]</code></em></code></strong>
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab$ <strong class="userinput"><code>cd lib/export</code></strong>
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab<li><p>The client module and the IRS library currently do not
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab support DNSSEC validation using DLV (the underlying modules
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab can handle it, but there is no tunable interface to enable
843e19887f64dde75055cf8842fc4db2171eff45johnlev resolver of the export library. In fact, it is not clear
843e19887f64dde75055cf8842fc4db2171eff45johnlev whether it should: trust anchors would be a system-wide
843e19887f64dde75055cf8842fc4db2171eff45johnlev configuration which would be managed by an administrator,
843e19887f64dde75055cf8842fc4db2171eff45johnlev while the stub resolver will be used by ordinary applications
843e19887f64dde75055cf8842fc4db2171eff45johnlev<li><p>Not all common <code class="filename">/etc/resolv.conf</code>
843e19887f64dde75055cf8842fc4db2171eff45johnlev options are supported
843e19887f64dde75055cf8842fc4db2171eff45johnlev in the IRS library. The only available options in this
843e19887f64dde75055cf8842fc4db2171eff45johnlev<a name="id2613064"></a>The dns.conf File</h3></div></div></div>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<p>The IRS library supports an "advanced" configuration file
843e19887f64dde75055cf8842fc4db2171eff45johnlev related to the DNS library for configuration parameters that
843e19887f64dde75055cf8842fc4db2171eff45johnlev would be beyond the capability of the
843e19887f64dde75055cf8842fc4db2171eff45johnlev Specifically, it is intended to provide DNSSEC related
843e19887f64dde75055cf8842fc4db2171eff45johnlev configuration parameters. By default the path to this
843e19887f64dde75055cf8842fc4db2171eff45johnlev configuration file is <code class="filename">/etc/dns.conf</code>.
843e19887f64dde75055cf8842fc4db2171eff45johnlev This module is very
843e19887f64dde75055cf8842fc4db2171eff45johnlev experimental and the configuration syntax or library interfaces
843e19887f64dde75055cf8842fc4db2171eff45johnlev may change in future versions. Currently, only the
843e19887f64dde75055cf8842fc4db2171eff45johnlev <span><strong class="command">trusted-keys</strong></span>
843e19887f64dde75055cf8842fc4db2171eff45johnlev statement is supported, whose syntax is the same as the same name
843e19887f64dde75055cf8842fc4db2171eff45johnlev of statement for <code class="filename">named.conf</code>. (See
843e19887f64dde75055cf8842fc4db2171eff45johnlev <a href="Bv9ARM.ch06.html#trusted-keys" title="trusted-keys Statement Grammar">the section called “<span><strong class="command">trusted-keys</strong></span> Statement Grammar”</a> for details.)</p>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<a name="id2613091"></a>Sample Applications</h3></div></div></div>
843e19887f64dde75055cf8842fc4db2171eff45johnlev<p>Some sample application programs using this API are
843e19887f64dde75055cf8842fc4db2171eff45johnlev provided for reference. The following is a brief description of
843e19887f64dde75055cf8842fc4db2171eff45johnlev these applications.
843e19887f64dde75055cf8842fc4db2171eff45johnlev<a name="id2613099"></a>sample: a simple stub resolver utility</h4></div></div></div>
843e19887f64dde75055cf8842fc4db2171eff45johnlev It sends a query of a given name (of a given optional RR type) to a
843e19887f64dde75055cf8842fc4db2171eff45johnlev specified recursive server, and prints the result as a list of
a576ab5b6e08c47732b3dedca9eaa8a8cbb85720rab RRs. It can also act as a validating stub resolver if a trust
843e19887f64dde75055cf8842fc4db2171eff45johnlev anchor is given via a set of command line options.</p>
843e19887f64dde75055cf8842fc4db2171eff45johnlev Usage: sample [options] server_address hostname
843e19887f64dde75055cf8842fc4db2171eff45johnlev Options and Arguments:
843e19887f64dde75055cf8842fc4db2171eff45johnlev specify the RR type of the query. The default is the A RR.
843e19887f64dde75055cf8842fc4db2171eff45johnlev [-a algorithm] [-e] -k keyname -K keystring
843e19887f64dde75055cf8842fc4db2171eff45johnlev specify a command-line DNS key to validate the answer. For
843e19887f64dde75055cf8842fc4db2171eff45johnlev example, to specify the following DNSKEY of example.com:
843e19887f64dde75055cf8842fc4db2171eff45johnlev����������������example.com.�3600�IN�DNSKEY�257�3�5�xxx<br>
-e -k example.com -K "xxx"
"domain". Example: -s example.com:2001:db8::1234
<a name="id2613190"></a>sample-async: a simple stub resolver, working asynchronously</h4></div></div></div>
<a name="id2613444"></a>sample-gai: getaddrinfo() and getnameinfo() test code</h4></div></div></div>
returned by getaddrinfo(). If the dns.conf file exists and
<a name="id2613527"></a>sample-update: a simple dynamic update client program</h4></div></div></div>
dynamic.example.com zone has an IPv6 address 2001:db8::1234,
$ <strong class="userinput"><code>sample-update -a sample-update -k Kxxx.+nnn+mmmm.key add "foo.dynamic.example.com 30 IN A 192.168.2.1"</code></strong></pre>
adds an A RR for foo.dynamic.example.com using the given key.
$ <strong class="userinput"><code>sample-update -a sample-update -k Kxxx.+nnn+mmmm.key delete "foo.dynamic.example.com 30 IN A"</code></strong></pre>
removes all A RRs for foo.dynamic.example.com using the given key.
$ <strong class="userinput"><code>sample-update -a sample-update -k Kxxx.+nnn+mmmm.key delete "foo.dynamic.example.com"</code></strong></pre>
removes all RRs for foo.dynamic.example.com using the given key.
<a name="id2614068"></a>nsprobe: domain/name server checker in terms of RFC 4074</h4></div></div></div>
"example.com". In general this domain name must be the apex
"www.example.com"). nsprobe first identifies the NS RRsets for