man Net::DNS::ZoneFile::Fast (3): parse BIND8/9 zone files

SYNOPSIS

use Net::DNS::ZoneFile::Fast;
my $rr = Net::DNS::ZoneFile::Fast::parse($zone_text);

DESCRIPTION

The Net::DNS::ZoneFile::Fast module provides an ability to parse zone files that BIND8 and BIND9 use, fast. Currently it provides a single function, parse(), which returns a reference to an array of traditional Net::DNS::RR objects, so that no new API has to be learned in order to manipulate zone records.

Great care was taken to ensure that parse() does its job as fast as possible, so it is interesting to use this module to parse huge zones. As an example datapoint, it takes less than 5 seconds to parse a 2.2 MB zone with about 72000 records on an Athlon XP 2600+ box.

On the other hand, it is likely that Net::DNS::RR objects that parse() returns are going to be further processed. To make it easier to link any record back to the zone file (say, to report a logical error like infamous `CNAME and other data' back to the user, or to do a zone file modification), parse() inserts line numbering information into Net::DNS::RR objects.

The module currently understands:

$GENERATE directive
$ORIGIN directive
$TTL directive
$INCLUDE directive (only while processing files or filehandles)
A records
AAAA records
CNAME records
DNAME records
HINFO records
LOC records
MX records
NS records
PTR records
RP records
SOA records
SRV records
TXT records
RRSIG records
DNSKEY records
DS records
NSEC records
RRSIG records

Non-standard third-party modules

Net::DNS.

Exports

None.

Subroutines

parse

Parses zone data and returns a reference to an array of Net::DNS::RR objects if successful. Takes the following named (no pun intended) parameters:

text: A semi-mandatory parameter, textual contents of the zone to be parsed.
fh: A semi-mandatory parameter, a file handle from which zone contents can be read for parsing.
file: A semi-mandatory parameter, a file name with the zone to parse.
origin: An optional parameter specifying zone origin. The default is ``.''. A trailing ``.'' is appended if necessary.
on_error: An optional parameter, user-defined error handler. If specified, it must be a subroutine reference, which will be called on any error. This subroutine will be passed two parameters: a line number in the zone, where the error occurred, and the error description.
soft_errors: By default, parse throws an exception on any error. Set this optional parameter to a true value to avoid this. The default is false, unless on_error is also specified, in which case it is true.
includes_root: An optional parameter. By default, any $INCLUDE directives encountered will be tested for existence and readability. If the base path of the included filename is not your current working directory, this test will fail. Set the includes_root to the same as your named.conf file to avoid this failure.
quiet: An optional parameter. By default, on any error, the error description is printed via warn(). Set quiet to a true value if you don't want this. The default is false, unless on_error is also specified, in which case it is true.
debug: An optional parameter. If set to true, will produce some debug printing. You probably don't want to use that.

One of text, fh, file must be specified. If more than one is specified at the same time, fh takes precedence over file, which takes precedence over text.

As a special case, if parse is called with a single, unnamed parameter, it is assumed to be a zone text.

If parse is unsuccessful, and does not throw an exception (because either on_error or soft_errors was specified), parse returns undef.

The returned Net::DNS::RR are normal in every respect, except that each of them has two extra keys, Line and Lines, which correspondingly are the line number in the zone text where the record starts, and the number of lines the record spans. This information can be accessed either via hash lookup ("$rr->{Line}"), or via an accessor method ("$rr->Line").

BUGS

The parse() subroutine is not re-entrant, and it probably will never be.

There is also no guarantee that parse() will successfully parse every zone parsable by BIND, and no guarantee that BIND will parse every zone parsable by parse(). That said, parse() appears to do the right thing on around 50000 real life zones I tested it with.

SOA serial numbers with a decimal point are not supported (they're not a legal zonefile contstruct, although bind8 supported them. Even bind is dropping support for them in future releases).

COPYRIGHT AND LICENSE

  "THE BEER-WARE LICENSE" (Revision 42)
  <[email protected]> wrote this module.  As long as you retain this notice
  you can do whatever you want with this stuff. If we meet some day, and
  you think this stuff is worth it, you can buy me a beer in return.
  Anton Berezin

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
   
  *  Redistributions of source code must retain the above copyright notice,
     this list of conditions and the following disclaimer.
   
  *  Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.
   
  *  Neither the name of SPARTA, Inc nor the names of its contributors may
     be used to endorse or promote products derived from this software
     without specific prior written permission.
   
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
  IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
   
  *  Redistributions of source code must retain the above copyright notice,
     this list of conditions and the following disclaimer.
   
  *  Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.
   
  *  Neither the name of SPARTA, Inc nor the names of its contributors may
     be used to endorse or promote products derived from this software
     without specific prior written permission.
   
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
  IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

CREDITS

Anton Berezin created the versions up until 0.5. Wes Hardaker at Sparta implemented the DNSSEC patches and took over maintenance of the module from 0.6 onward.

Anton's original CREDITS section:

  This module was largely inspired by the I<Net::DNS::ZoneFile> module
  by Luis E. Munoz.
  Many thanks to Phil Regnauld and Luis E. Munoz for discussions.