1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<!--
- Copyright (C) 2000-2019 Internet Systems Consortium, Inc. ("ISC")
-
- This Source Code Form is subject to the terms of the Mozilla Public
- License, v. 2.0. If a copy of the MPL was not distributed with this
- file, You can obtain one at http://mozilla.org/MPL/2.0/.
-->
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Appendix�D.�BIND 9 DNS Library Support</title>
<meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
<link rel="home" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual">
<link rel="up" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual">
<link rel="prev" href="Bv9ARM.ch11.html" title="Appendix�C.�General DNS Reference Information">
<link rel="next" href="Bv9ARM.ch13.html" title="Manual pages">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<div class="navheader">
<table width="100%" summary="Navigation header">
<tr><th colspan="3" align="center">Appendix�D.�BIND 9 DNS Library Support</th></tr>
<tr>
<td width="20%" align="left">
<a accesskey="p" href="Bv9ARM.ch11.html">Prev</a>�</td>
<th width="60%" align="center">�</th>
<td width="20%" align="right">�<a accesskey="n" href="Bv9ARM.ch13.html">Next</a>
</td>
</tr>
</table>
<hr>
</div>
<div class="appendix">
<div class="titlepage"><div><div><h1 class="title">
<a name="Bv9ARM.ch12"></a>BIND 9 DNS Library Support</h1></div></div></div>
<div class="toc">
<p><b>Table of Contents</b></p>
<dl class="toc">
<dt><span class="section"><a href="Bv9ARM.ch12.html#bind9.library">BIND 9 DNS Library Support</a></span></dt>
<dd><dl>
<dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.5">Installation</a></span></dt>
<dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.6">Known Defects/Restrictions</a></span></dt>
<dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.7">The dns.conf File</a></span></dt>
<dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.8">Sample Applications</a></span></dt>
<dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.9">Library References</a></span></dt>
</dl></dd>
</dl>
</div>
<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="bind9.library"></a>BIND 9 DNS Library Support</h2></div></div></div>
<p>
This version of BIND 9 "exports" its internal libraries so
that they can be used by third-party applications more easily (we
call them "export" libraries in this document). Certain library
functions are altered from specific BIND-only behavior to more generic
behavior when used by other applications; to enable this generic behavior,
the calling program initializes the libraries by calling
<span class="command"><strong>isc_lib_register()</strong></span>.
</p>
<p>
In addition to DNS-related APIs that are used within BIND 9, the
libraries provide the following features:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The "DNS client" module. This is a higher level API that
provides an interface to name resolution, single DNS transaction
with a particular server, and dynamic update. Regarding name
resolution, it supports advanced features such as DNSSEC validation
and caching. This module supports both synchronous and asynchronous
mode.
</p>
</li>
<li class="listitem">
<p>
The "IRS" (Information Retrieval System) library. It provides an
interface to parse the traditional <code class="filename">resolv.conf</code>
file and more advanced, DNS-specific configuration file for the
rest of this package (see the description for the
<code class="filename">dns.conf</code> file below).
</p>
</li>
<li class="listitem">
<p>
As part of the IRS library, the standard address-name
mapping functions, <span class="command"><strong>getaddrinfo()</strong></span> and
<span class="command"><strong>getnameinfo()</strong></span>, are provided. They use the
DNSSEC-aware validating resolver backend, and could use other
advanced features of the BIND 9 libraries such as caching. The
<span class="command"><strong>getaddrinfo()</strong></span> function resolves both A
and AAAA RRs concurrently when the address family is
unspecified.
</p>
</li>
<li class="listitem">
<p>
An experimental framework to support other event
libraries than BIND 9's internal event task system.
</p>
</li>
</ul></div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.13.2.5"></a>Installation</h3></div></div></div>
<pre class="screen">
$ <strong class="userinput"><code>make install</code></strong>
</pre>
<p>
Normal installation of BIND will also install library object
and header files. Root privilege is normally required.
</p>
<p>
To see how to build your own application after the installation, see
<code class="filename">lib/samples/Makefile-postinstall.in</code>.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.13.2.6"></a>Known Defects/Restrictions</h3></div></div></div>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The "fixed" RRset order is not (currently) supported in the export
library. If you want to use "fixed" RRset order for, e.g.
<span class="command"><strong>named</strong></span> while still building the export library
even without the fixed order support, build them separately:
</p>
<pre class="screen">
$ <strong class="userinput"><code>./configure --enable-fixed-rrset <em class="replaceable"><code>[other flags, but not --enable-exportlib]</code></em></code></strong>
$ <strong class="userinput"><code>make</code></strong>
$ <strong class="userinput"><code>./configure --enable-exportlib <em class="replaceable"><code>[other flags, but not --enable-fixed-rrset]</code></em></code></strong>
$ <strong class="userinput"><code>cd lib/export</code></strong>
$ <strong class="userinput"><code>make</code></strong>
</pre>
<p>
</p>
</li>
<li class="listitem">
<p>
RFC 5011 is not supported in the validating stub resolver of the
export library. In fact, it is not clear whether it should: trust
anchors would be a system-wide configuration which would be managed
by an administrator, while the stub resolver will be used by
ordinary applications run by a normal user.
</p>
</li>
<li class="listitem">
<p>
Not all common <code class="filename">/etc/resolv.conf</code> options are
supported in the IRS library. The only available options in this
version are <span class="command"><strong>debug</strong></span> and <span class="command"><strong>ndots</strong></span>.
</p>
</li>
</ul></div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.13.2.7"></a>The dns.conf File</h3></div></div></div>
<p>
The IRS library supports an "advanced" configuration file related to
the DNS library for configuration parameters that would be beyond the
capability of the <code class="filename">resolv.conf</code> file.
Specifically, it is intended to provide DNSSEC related configuration
parameters. By default the path to this configuration file is
<code class="filename">/etc/dns.conf</code>. This module is very experimental
and the configuration syntax or library interfaces may change in
future versions. Currently, only the <span class="command"><strong>trusted-keys</strong></span>
statement is supported, whose syntax is the same as the same
statement in <code class="filename">named.conf</code>. (See
<a class="xref" href="Bv9ARM.ch06.html#trusted-keys" title="trusted-keys Statement Grammar">the section called “<span class="command"><strong>trusted-keys</strong></span> Statement Grammar”</a> for details.)
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.13.2.8"></a>Sample Applications</h3></div></div></div>
<p>
Some sample application programs using this API are provided for
reference. The following is a brief description of these
applications.
</p>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="id-1.13.2.8.3"></a>sample: a simple stub resolver utility</h4></div></div></div>
<p>
Sends a query of a given name (of a given optional RR type) to a
specified recursive server and prints the result as a list of RRs.
It can also act as a validating stub resolver if a trust anchor is
given via a set of command line options.
</p>
<p>
Usage: sample [options] server_address hostname
</p>
<p>
Options and Arguments:
</p>
<div class="variablelist"><dl class="variablelist">
<dt><span class="term">-t RRtype</span></dt>
<dd>
<p>
specify the RR type of the query. The default is the A RR.
</p>
</dd>
<dt><span class="term">[-a algorithm] [-e] -k keyname -K keystring</span></dt>
<dd>
<p>
specify a command-line DNS key to validate the answer. For
example, to specify the following DNSKEY of example.com:
</p>
<div class="literallayout"><p><br>
��������������example.com.�3600�IN�DNSKEY�257�3�5�xxx<br>
������</p></div>
<p>
specify the options as follows:
</p>
<pre class="screen">
<strong class="userinput"><code>-e -k example.com -K "xxx"</code></strong>
</pre>
<p>
-e means that this key is a zone's "key signing key" (also known
as "secure entry point").
When -a is omitted rsasha1 will be used by default.
</p>
</dd>
<dt><span class="term">-s domain:alt_server_address</span></dt>
<dd>
<p>
specify a separate recursive server address for the specific
"domain". Example: -s example.com:2001:db8::1234
</p>
</dd>
<dt><span class="term">server_address</span></dt>
<dd>
<p>
an IP(v4/v6) address of the recursive server to which queries
are sent.
</p>
</dd>
<dt><span class="term">hostname</span></dt>
<dd>
<p>
the domain name for the query
</p>
</dd>
</dl></div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="id-1.13.2.8.4"></a>sample-async: a simple stub resolver, working asynchronously</h4></div></div></div>
<p>
Similar to "sample", but accepts a list
of (query) domain names as a separate file and resolves the names
asynchronously.</p>
<p>
Usage: sample-async [-s server_address] [-t RR_type] input_file</p>
<p>
Options and Arguments:
</p>
<div class="variablelist"><dl class="variablelist">
<dt><span class="term">-s server_address</span></dt>
<dd>
an IPv4 address of the recursive server to which queries are sent.
(IPv6 addresses are not supported in this implementation)
</dd>
<dt><span class="term">-t RR_type</span></dt>
<dd>
specify the RR type of the queries. The default is the A
RR.
</dd>
<dt><span class="term">input_file</span></dt>
<dd>
a list of domain names to be resolved. each line consists of a
single domain name. Example:
<div class="literallayout"><p><br>
������www.example.com<br>
������mx.example.net<br>
������ns.xxx.example<br>
������</p></div>
</dd>
</dl></div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="id-1.13.2.8.5"></a>sample-request: a simple DNS transaction client</h4></div></div></div>
<p>
Sends a query to a specified server, and prints the response with
minimal processing. It doesn't act as a "stub resolver": it stops
the processing once it gets any response from the server, whether
it's a referral or an alias (CNAME or DNAME) that would require
further queries to get the ultimate answer. In other words, this
utility acts as a very simplified <span class="command"><strong>dig</strong></span>.
</p>
<p>
Usage: sample-request [-t RRtype] server_address hostname
</p>
<p>
Options and Arguments:
</p>
<div class="variablelist"><dl class="variablelist">
<dt><span class="term">-t RRtype</span></dt>
<dd>
<p>
specify the RR type of the queries. The default is the A RR.
</p>
</dd>
<dt><span class="term">server_address</span></dt>
<dd>
<p>
an IP(v4/v6) address of the recursive server to which
the query is sent.
</p>
</dd>
<dt><span class="term">hostname</span></dt>
<dd>
<p>
the domain name for the query
</p>
</dd>
</dl></div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="id-1.13.2.8.6"></a>sample-gai: getaddrinfo() and getnameinfo() test code</h4></div></div></div>
<p>
This is a test program to check <span class="command"><strong>getaddrinfo()</strong></span> and
<span class="command"><strong>getnameinfo()</strong></span> behavior. It takes a host name as an
argument, calls <span class="command"><strong>getaddrinfo()</strong></span> with the given host
name, and calls <span class="command"><strong>getnameinfo()</strong></span> with the resulting
IP addresses returned by <span class="command"><strong>getaddrinfo()</strong></span>. If the
dns.conf file exists and defines a trust anchor, the underlying
resolver will act as a validating resolver, and
<span class="command"><strong>getaddrinfo()</strong></span>/<span class="command"><strong>getnameinfo()</strong></span>
will fail with an EAI_INSECUREDATA error when DNSSEC validation
fails.
</p>
<p>
Usage: sample-gai hostname
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="id-1.13.2.8.7"></a>sample-update: a simple dynamic update client program</h4></div></div></div>
<p>
Accepts a single update command as a command-line argument, sends
an update request message to the authoritative server, and shows
the response from the server. In other words, this is a simplified
<span class="command"><strong>nsupdate</strong></span>.
</p>
<p>
Usage: sample-update [options] (add|delete) "update data"
</p>
<p>
Options and Arguments:
</p>
<div class="variablelist"><dl class="variablelist">
<dt><span class="term">-a auth_server</span></dt>
<dd>
<p>
An IP address of the authoritative server that has authority
for the zone containing the update name. This should
normally be the primary authoritative server that accepts
dynamic updates. It can also be a secondary server that is
configured to forward update requests to the primary server.
</p>
</dd>
<dt><span class="term">-k keyfile</span></dt>
<dd>
<p>
A TSIG key file to secure the update transaction. The
keyfile format is the same as that for the nsupdate utility.
</p>
</dd>
<dt><span class="term">-p prerequisite</span></dt>
<dd>
<p>
A prerequisite for the update (only one prerequisite can be
specified). The prerequisite format is the same as that is
accepted by the nsupdate utility.
</p>
</dd>
<dt><span class="term">-r recursive_server</span></dt>
<dd>
<p>
An IP address of a recursive server that this utility will
use. A recursive server may be necessary to identify the
authoritative server address to which the update request is
sent.
</p>
</dd>
<dt><span class="term">-z zonename</span></dt>
<dd>
<p>
The domain name of the zone that contains
</p>
</dd>
<dt><span class="term">(add|delete)</span></dt>
<dd>
<p>
Specify the type of update operation. Either "add" or
"delete" must be specified.
</p>
</dd>
<dt><span class="term">"update data"</span></dt>
<dd>
<p>
Specify the data to be updated. A typical example of the
data would look like "name TTL RRtype RDATA".
</p>
</dd>
</dl></div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p>
In practice, either -a or -r must be specified. Others can be
optional; the underlying library routine tries to identify the
appropriate server and the zone name for the update.
</p>
</div>
<p>
Examples: assuming the primary authoritative server of the
dynamic.example.com zone has an IPv6 address 2001:db8::1234,
</p>
<pre class="screen">
$ <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>
<p>
adds an A RR for foo.dynamic.example.com using the given key.
</p>
<pre class="screen">
$ <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>
<p>
removes all A RRs for foo.dynamic.example.com using the given key.
</p>
<pre class="screen">
$ <strong class="userinput"><code>sample-update -a sample-update -k Kxxx.+nnn+mmmm.key delete "foo.dynamic.example.com"</code></strong></pre>
<p>
removes all RRs for foo.dynamic.example.com using the given key.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="id-1.13.2.8.8"></a>nsprobe: domain/name server checker in terms of RFC 4074</h4></div></div></div>
<p>
Checks a set of domains to see the name servers of the domains
behave correctly in terms of RFC 4074. This is included in the set
of sample programs to show how the export library can be used in a
DNS-related application.
</p>
<p>
Usage: nsprobe [-d] [-v [-v...]] [-c cache_address] [input_file]
</p>
<p>
Options
</p>
<div class="variablelist"><dl class="variablelist">
<dt><span class="term">-d</span></dt>
<dd>
<p>
Run in "debug" mode. With this option nsprobe will dump
every RRs it receives.
</p>
</dd>
<dt><span class="term">-v</span></dt>
<dd>
<p>
Increase verbosity of other normal log messages. This can be
specified multiple times.
</p>
</dd>
<dt><span class="term">-c cache_address</span></dt>
<dd>
<p>
Specify an IP address of a recursive (caching) name server.
nsprobe uses this server to get the NS RRset of each domain
and the A and/or AAAA RRsets for the name servers. The
default value is 127.0.0.1.
</p>
</dd>
<dt><span class="term">input_file</span></dt>
<dd>
<p>
A file name containing a list of domain (zone) names to be
probed. when omitted the standard input will be used. Each
line of the input file specifies a single domain name such as
"example.com". In general this domain name must be the apex
name of some DNS zone (unlike normal "host names" such as
"www.example.com"). nsprobe first identifies the NS RRsets
for the given domain name, and sends A and AAAA queries to
these servers for some "widely used" names under the zone;
specifically, adding "www" and "ftp" to the zone name.
</p>
</dd>
</dl></div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.13.2.9"></a>Library References</h3></div></div></div>
<p>
As of this writing, there is no formal "manual" for the libraries,
except this document, header files (some of which provide pretty
detailed explanations), and sample application programs.
</p>
</div>
</div>
</div>
<div class="navfooter">
<hr>
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left">
<a accesskey="p" href="Bv9ARM.ch11.html">Prev</a>�</td>
<td width="20%" align="center">�</td>
<td width="40%" align="right">�<a accesskey="n" href="Bv9ARM.ch13.html">Next</a>
</td>
</tr>
<tr>
<td width="40%" align="left" valign="top">Appendix�C.�General <acronym class="acronym">DNS</acronym> Reference Information�</td>
<td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td>
<td width="40%" align="right" valign="top">�Manual pages</td>
</tr>
</table>
</div>
<p xmlns:db="http://docbook.org/ns/docbook" style="text-align: center;">BIND 9.11.5-P4 (Extended Support Version)</p>
</body>
</html>
|
