- adns
+ GNU adns
- Advanced, easy to use, asynchronous-capable DNS client library.
+ Advanced, easy to use, asynchronous-capable DNS client library and
+ utilities.
- adns is a resolver library for C (and C++) programs. In contrast with
- the existing interfaces, gethostbyname et al and libresolv, it has the
- following features:
- * It is reasonably easy to use for simple programs which just want
- to translate names to addresses, look up MX records, etc.
+ adns is a resolver library for C (and C++) programs, and a collection
+ of useful DNS resolver utilities.
+
+C library
+
+ In contrast with the standard interfaces, gethostbyname et al and
+ libresolv, it has the following features:
+ * It is reasonably easy to use for simple programs which just want to
+ translate names to addresses, look up MX records, etc.
* It can be used in an asynchronous, non-blocking, manner. Many
queries can be handled simultaneously.
* Responses are decoded automatically into a natural representation
- for a C program - there is no need to deal with DNS packet
- formats.
+ for a C program - there is no need to deal with DNS packet and
+ RRDATA formats.
* Sanity checking (eg, name syntax checking, reverse/forward
- correspondence, CNAME pointing to CNAME) is performed
- automatically.
- * Time-to-live, CNAME and other similar information is returned in
- an easy-to-use form, without affecting ease-of-use.
+ correspondence, CNAME pointing to CNAME) is performed automatically
+ by default.
+ * Time-to-live, CNAME and other similar information is returned in an
+ easy-to-use form, without getting in the way.
* There is no global state in the library; resolver state is an
opaque data structure which the client creates explicitly. A
program can have several instances of the resolver.
* Errors are reported to the application in a way that distinguishes
the various causes of failure properly.
- * Understands conventional resolv.conf, but this can overridden by
- environment variables.
+ * adns understands conventional resolv.conf, but this can overridden
+ by environment variables.
* Flexibility. For example, the application can tell adns to: ignore
- environment variables (for setuid programs), disable sanity checks
- eg to return arbitrary data, override or ignore resolv.conf in
- favour of supplied configuration, change its caching behaviour,
- use a different flow of control model, etc.
+ environment variables (for setuid programs), disable hostname
+ syntax sanity checks to return arbitrary data, override or ignore
+ resolv.conf in favour of supplied configuration, etc.
* Believed to be correct ! For example, will correctly back off to
TCP in case of long replies or queries, or to other nameservers if
several are available. It has sensible handling of bad responses
etc.
-Forthcoming:
-
- I hope that future versions may also have the following features:
- * The library can be used by threads in a multithreaded program in a
- natural way. It will multiplex many threads' queries through a
- single query socket.
- * Limited caching behaviour.
- * IPv6 support.
-
- (Technical note: adns requires a real nameserver like BIND running on
- the same system or a nearby one, which must be willing to provide
- `recursive service'. I.e., adns is a `stub resolver'. All properly
- configured UN*X and GNU systems will already have such nameserver(s);
- they are usually listed in /etc/resolv.conf.)
+DNS utility programs
+
+ adns also comes with a number of utility programs for use from the
+ command line and in scripts:
+ * adnslogres is a much faster version of Apache's logresolv program.
+ * adnsresfilter is a filter which copies its input to its output,
+ replacing IP addresses by the corresponding names, without unduly
+ delaying the output. For example, you can usefully pipe the output
+ of netstat -n, tcpdump -ln, and the like, into it.
+ * adnshost is a general-purpose DNS lookup utility which can be used
+ easily in from the command line and from shell scripts to do simple
+ lookups. In a more advanced mode it can be used as a
+ general-purpose DNS helper program for scripting languages which
+ can invoke and communicate with subprocesses. See the [1]adnshost
+ usage message for a summary of its capabilities.
+
+Documentation
+
+ I'm afraid there is no manual yet. However, competent C programmers
+ should be able to use the library based on the [2]commented adns.h
+ header file, and the usage messages for the programs should be
+ sufficient.
+
+Feedback
+
+ I'd be pleased if you would let me know if you're using my library in
+ your project, and what you think of it.
+
+ Bug reports should be reported to the [3]GNU Debbugs. Send an email to
+ submit@debbugs.gnu.org and at the top of your email, in a paragraph of
+ its own, write the single line
+Package: adns
+
+ Your bug report will be published via to the adns-discuss list.
+
+ Feedback and discussion takes place on the adns-discuss list. You can
+ mail me privately at ijackson@chiark.greenend.org.uk.
+
+Mailinglists
+
+ I have set up mailinglists adns-announce and adns-discuss. The
+ announcements list is moderated and will contain only announcements of
+ important bugs, new versions, etc.
+
+ There are [4]archives and subscription web pages, or you can subscribe
+ by sending mail containing the word `subscribe' to
+ adns-announce-REQUEST@chiark.greenend.org.uk or
+ adns-discuss-REQUEST@chiark.greenend.org.uk.
+
+Documentation
+
+ * [5]adns.h API header file with documentation comments
+ * [6]usage message for adnshost
+
+Download and source code
+
+ * The [7]current release as a gzipped tarfile.
+ * [8]Previous versions and other files (including OpenPGP
+ signatures).
+ * [9]master git (version control) repository browser.
+
+ adns is also available from the [10]GNU Project FTP servers and their
+ [11]mirrors.
+
+Installation note
+
+ adns requires a real nameserver like BIND running on the same system or
+ a nearby one, which must be willing to provide `recursive service'.
+ I.e., adns is a `stub resolver'.
+
+ adns requires that your real nameserver is on the same machine, or
+ connected via a secure network, so that an attacker cannot fake the
+ replies to adns's queries.
+
+References and related projects
+
+ * [12]Python bindings by Andy Dustman.
+ * [13]liboop event loop library has a built-in binding for adns.
+ * [14]port to MS Visual Studio 6 C++ by Jarle Aase.
+
+Copyright and licensing
+
+ adns is Copyright 1997-2000,2003,2006,2014-2016 Ian Jackson, Copyright
+ 2014 Mark Wooding, Copyright 1999-2000,2003,2006 Tony Finch, and
+ Copyright (C) 1991 Massachusetts Institute of Technology.
+
+ adns is free software; you can redistribute it and/or modify it under
+ the terms of the GNU General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your
+ option) any later version.
+
+ This program and documentation is distributed in the hope that it will
+ be useful, but without any warranty; without even the implied warranty
+ of merchantability or fitness for a particular purpose. See the [15]GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with adns, or one should be available above; if not, write to the
+ [16]Free Software Foundation or email ijackson@chiark.greenend.org.uk.
+ __________________________________________________________________
+
+ Ian Jackson / ijackson@chiark.greenend.org.uk.
+
+ [17]GNU home page; [18]chiark home page; [19]site or mirror home page
+
+ This web page is Copyright (C)1996-2005,2014-2016 Ian Jackson. See the
+ [20]Copyright/acknowledgements.
+
+References
+
+ 1. http://www.chiark.greenend.org.uk/~ian/adns/docs/adnshost.txt
+ 2. http://www.chiark.greenend.org.uk/~ian/adns/docs/adns.h.txt
+ 3. http://debbugs.gnu.org/
+ 4. http://www.chiark.greenend.org.uk/mailman/listinfo
+ 5. http://www.chiark.greenend.org.uk/~ian/adns/docs/adns.h.txt
+ 6. http://www.chiark.greenend.org.uk/~ian/adns/docs/adnshost.txt
+ 7. http://www.chiark.greenend.org.uk/~ian/adns/adns.tar.gz
+ 8. http://www.chiark.greenend.org.uk/~ian/adns/ftp/
+ 9. http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git/adns.git/
+ 10. http://www.gnu.org/
+ 11. http://www.gnu.org/order/ftp.html
+ 12. http://code.google.com/p/adns-python
+ 13. http://www.lysator.liu.se/liboop/
+ 14. http://adns.jgaa.com/
+ 15. http://www.chiark.greenend.org.uk/~ian/adns/docs/COPYING.txt
+ 16. http://www.fsf.org/
+ 17. http://www.gnu.org/
+ 18. http://www.chiark.greenend.org.uk/
+ 19. file:///
+ 20. http://www.chiark.greenend.org.uk/~ian/sw-www-copy.html
~ianmdlvl / adns.git / blobdiff