mdw@git.distorted.org.uk Git - adns/blob - README

   1
   2                                    GNU adns
   3
   4    Advanced, easy to use, asynchronous-capable DNS client library and
   5    utilities.
   6
   7    adns is a resolver library for C (and C++) programs. In contrast with
   8    the existing interfaces, gethostbyname et al and libresolv, it has the
   9    following features:
  10      * It is reasonably easy to use for simple programs which just want
  11        to translate names to addresses, look up MX records, etc.
  12      * It can be used in an asynchronous, non-blocking, manner. Many
  13        queries can be handled simultaneously.
  14      * Responses are decoded automatically into a natural representation
  15        for a C program - there is no need to deal with DNS packet
  16        formats.
  17      * Sanity checking (eg, name syntax checking, reverse/forward
  18        correspondence, CNAME pointing to CNAME) is performed
  19        automatically.
  20      * Time-to-live, CNAME and other similar information is returned in
  21        an easy-to-use form, without getting in the way.
  22      * There is no global state in the library; resolver state is an
  23        opaque data structure which the client creates explicitly. A
  24        program can have several instances of the resolver.
  25      * Errors are reported to the application in a way that distinguishes
  26        the various causes of failure properly.
  27      * Understands conventional resolv.conf, but this can overridden by
  28        environment variables.
  29      * Flexibility. For example, the application can tell adns to: ignore
  30        environment variables (for setuid programs), disable sanity checks
  31        eg to return arbitrary data, override or ignore resolv.conf in
  32        favour of supplied configuration, etc.
  33      * Believed to be correct ! For example, will correctly back off to
  34        TCP in case of long replies or queries, or to other nameservers if
  35        several are available. It has sensible handling of bad responses
  36        etc.
  37
  38    adns also comes with a number of utility programs for use from the
  39    command line and in scripts:
  40      * adnslogres is a much faster version of Apache's logresolv program.
  41      * adnsresfilter is a filter which copies its input to its output,
  42        replacing IP addresses by the corresponding names, without unduly
  43        delaying the output. For example, you can usefully pipe the output
  44        of netstat -n, tcpdump -ln, and the like, into it.
  45      * adnshost is a general-purpose DNS lookup utility which can be used
  46        easily in shell scripts to do simple lookups. In a more advanced
  47        mode it can be used as a general-purpose DNS helper program for
  48        scripting languages which can invoke and communicate with
  49        subprocesses.
  50
  51 Forthcoming:
  52
  53    A native Perl interface is in the works, thanks to Tony Finch.
  54
  55    I hope that future versions may also have the following features:
  56      * The library should be useable by threads in a multithreaded
  57        program in a natural way. It should multiplex many threads'
  58        queries through a single query socket.
  59      * IPv6 support.
  60      * Some kind of awareness of DNSSEC.
  61      * Possibly some very limited caching behaviour.
  62
  63    (Technical note: adns requires a real nameserver like [1]BIND or
  64    [2]Dents running on the same system or a nearby one, which must be
  65    willing to provide `recursive service'. I.e., adns is a `stub
  66    resolver'. All properly configured UN*X and GNU systems will already
  67    have such nameserver(s); they are usually listed in /etc/resolv.conf.)
  68
  69 Documentation
  70
  71    I'm afraid there is no manual yet. However, competent C programmers
  72    should be able to use the library based on the [3]commented adns.h
  73    header file.
  74
  75 Feedback
  76
  77    I'd be pleased if you would let me know if you're using my library in
  78    your project, and what you think of it.
  79
  80    If you are subscribed to adns-discuss please send feedback, including
  81    bug reports, there; otherwise send mail to
  82    adns-bugreports@chiark.greenend.org.uk. If you'd prefer that your
  83    message wasn't forwarded to the adns-bugreports list, send it to
  84    adns-maint@chiark.greendend.org.uk.
  85
  86 Mailinglists
  87
  88    I have set up mailinglists adns-announce and adns-discuss. The
  89    announcements list is moderated and will contain only announcements of
  90    important bugs, new versions, &c. The bug reports address mentioned
  91    above is also a mailing list; feel free to subscribe to it.
  92
  93    There are [4]archives and subscription web pages, or you can subscribe
  94    by sending mail containing the word `subscribe' to
  95    adns-announce-REQUEST@chiark.greenend.org.uk or
  96    adns-discuss-REQUEST@chiark.greenend.org.uk.
  97
  98 Download
  99
 100    Available for download from [5]chiark.greenend.org.uk are:
 101      * The [6]current beta version as a gzipped tarfile.
 102      * [7]adns.h API header file with comments (currently there is no
 103        manual, sorry).
 104      * All versions released so far are also available via [8]anonymous
 105        FTP.
 106      * A mirror of my CVS repository is available via rsync from
 107        rsync.chiark.greenend.org.uk::ftp/users/ian/cvs-pub/adns (use FTP
 108        first to find your way around), or via [9]cvsweb.
 109
 110    adns is also available from the [10]GNU Project FTP servers and their
 111    [11]mirrors.
 112
 113 Copyright and licensing
 114
 115    adns is Copyright 1997-2000 Ian Jackson, Copyright 1999 Tony Finch,
 116    and Copyright (C) 1991 Massachusetts Institute of Technology.
 117
 118    adns is free software; you can redistribute it and/or modify it under
 119    the terms of the GNU General Public License as published by the Free
 120    Software Foundation; either version 2 of the License, or (at your
 121    option) any later version.
 122
 123    This program and documentation is distributed in the hope that it will
 124    be useful, but without any warranty; without even the implied warranty
 125    of merchantability or fitness for a particular purpose. See the
 126    [12]GNU General Public License for more details.
 127
 128    You should have received a copy of the GNU General Public License
 129    along with adns, or one should be available above; if not, write to
 130    the [13]Free Software Foundation, 59 Temple Place - Suite 330, Boston,
 131    MA 02111-1307, USA, or email adns-maint@chiark.greenend.org.uk.
 132      _________________________________________________________________
 133
 134    [14]Ian Jackson / [15]adns-maint@chiark.greenend.org.uk; more [16]free
 135    software by me.
 136
 137    [17]GNU home page; [18]chiark home page; [19]site or mirror home page
 138
 139    This web page is Copyright (C)1996-2000 Ian Jackson. See the
 140    [20]Copyright/acknowledgements.
 141
 142    Use any browser - [21]Campaign for a non-browser-specific WWW
 143
 144 References
 145
 146    1. http://www.isc.org/view.cgi?/products/BIND/index.phtml
 147    2. http://www.dents.org/
 148    3. http://www.chiark.greenend.org.uk/~ian/adns/adns.h.txt
 149    4. http://www.chiark.greenend.org.uk/mailman/listinfo
 150    5. http://www.chiark.greenend.org.uk/~ian/adns/
 151    6. http://www.chiark.greenend.org.uk/~ian/adns/adns.tar.gz
 152    7. http://www.chiark.greenend.org.uk/~ian/adns/adns.h.txt
 153    8. ftp://ftp.chiark.greenend.org.uk/users/ian/adns/
 154    9. http://www.chiark.greenend.org.uk/ucgi/~ijackson/cvsweb/adns/
 155   10. http://www.gnu.org/
 156   11. http://www.gnu.org/order/ftp.html
 157   12. http://www.chiark.greenend.org.uk/~ian/COPYING.txt
 158   13. http://www.fsf.org/
 159   14. http://www.chiark.greenend.org.uk/
 160   15. mailto:adns-maint@chiark.greenend.org.uk
 161   16. http://www.chiark.greenend.org.uk/~ian/software/
 162   17. http://www.gnu.org/
 163   18. http://www.chiark.greenend.org.uk/
 164   19. http://www.chiark.greenend.org.uk/
 165   20. http://www.chiark.greenend.org.uk/~ian/sw-www-copy.html
 166   21. http://www.anybrowser.org/campaign/