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DNS::ZoneParse(3) |
User Contributed Perl Documentation |
DNS::ZoneParse(3) |
DNS::ZoneParse - Parse and manipulate DNS Zone Files.
use DNS::ZoneParse;
my $zonefile = DNS::ZoneParse->new("/path/to/dns/zonefile.db", $origin);
# Get a reference to the MX records
my $mx = $zonefile->mx;
# Change the first mailserver on the list
$mx->[0] = { host => 'mail.localhost.com',
priority => 10,
name => '@' };
# update the serial number
$zonefile->new_serial();
# write the new zone file to disk
my $newzone;
open($newzone, '>', '/path/to/dns/zonefile.db') or die "error";
print $newzone $zonefile->output();
close $newzone;
perl Makefile.PL
make
make test
make install
Win32 users substitute "make" with "nmake" or
equivalent. nmake is available at
http://download.microsoft.com/download/vc15/Patch/1.52/W95/EN-US/Nmake15.exe
This module will parse a Zone File and put all the Resource Records (RRs) into
an anonymous hash structure. Various record types are supported, see the
methods section for details. It could be useful for maintaining DNS zones, or
for transferring DNS zones to other servers. If you want to generate an
XML-friendly version of your zone files, it is easy to use XML::Simple with
this module once you have parsed the zone file.
DNS::ZoneParse scans the DNS zone file - removes comments and
seperates the file into its constituent records. It then parses each record
and stores the records internally. See below for information on the accessor
methods.
- new
- This creates the DNS::ZoneParse object and loads the zone file.
Example:
my $zonefile =
DNS::ZoneParse->new("/path/to/zonefile.db");
You can also initialise the object with the contents of a
file:
my $zonefile = DNS::ZoneParse->new(
\$zone_contents );
You can pass a second, optional parameter to the constructor
to supply an $origin if none can be found in the
zone file.
my $zonefile = DNS::ZoneParse->new( \$zone_contents, $origin );
You can pass a third, optional parameter to the constructor to
supply a callback which will be called whenever an unparsable line is
encountered in the zone file. See
"on_unparseable_line" for details on
this parameter and how errors are handled when parsing zone files.
If you plan to pass a on_unparseable_line callback but do not
wish to specify an $origin, pass 'undef' as the
$origin parameter.
- a(), cname(), srv(), mx(), ns(), ptr(),
txt(), spf(), hinfo(), rp(), loc()
- These methods return references to the resource records. For example:
my $mx = $zonefile->mx;
Returns the mx records in an array reference.
All records (except SOA) have the following properties: 'ttl',
'class', 'host', 'name', 'ORIGIN'.
MX records also have a 'priority' property.
SRV records also have 'priority', 'weight' and 'port'
properties.
TXT records also have a 'text' property representing the
record's 'txt-data' descriptive text.
SPF records also have a 'spf' property representing the
record's 'spf-data' descriptive text.
HINFO records also have 'cpu' and 'os' properties.
RP records also have 'mbox' and 'text' properties.
LOC records also have 'd1', 'm1', 's1', 'NorS', 'd2', 'm2',
's2', 'EorW', 'alt', 'siz', 'hp', and 'vp', as per RFC 1876.
If there are no records of a given type in the zone, the call
will croak with an error message about an invalid method. (This is not
an ideal behavior, but has been kept for backwards compatibility.)
The 'ORIGIN' property is the fully-qualified origin of the
record. See fqname for details on constructing a fully qualified domain
name. Note: for SOA records, the 'ORIGIN' will match the 'origin'
property when the SOA record is specified as fully qualified.
- soa()
- Returns a hash reference with the following properties: 'serial',
'origin', 'primary', 'refresh', 'retry', 'ttl', 'minimumTTL', 'email',
'expire', 'class', 'ORIGIN'.
The 'ORIGIN' property is returned separate from 'origin'
property, though the data may be the same. 'ORIGIN' represents the
implicit origin for the record while 'origin' represents the origin
specified on the SOA line in the file.
If the 'origin' value is relative (that is, does not end with
a '.'), the actual zone for which the SOA line applies must be computed
by concatenating the 'origin' and 'ORIGIN' values. See fqname for
details. If the 'origin' value is absolute, no computation is necessary
and 'origin' is the same as 'ORIGIN'.
- generate()
- Returns an array of hashes representing $GENERATE
directives present in the zone. Note, $GENERATE
directives are BIND-specific additions. They are not expanded by
DNS::ZoneParse, but users are able to access and modify these directives.
The following properties are returned:
'range', 'lhs', 'ttl', 'class', 'type', 'rhs', 'ORIGIN'.
See the BIND documentation for details on the syntax and usage
of the $GENERATE directive.
- dump
- Returns a copy of the datastructute that stores all the resource records.
This might be useful if you want to quickly transform the data into
another format, such as XML.
- fqname
- Takes a single parameter, a hash reference containing a record.
Returns the fully qualified name of this record, with a
trailing '.'. In most cases this is as simple as concatenating the
'name' and 'ORIGIN' with a '.' unless 'name' is '@', in which case the
fqname is simply the 'ORIGIN'. For SOA records, the same process is
performed on the 'origin' instead of 'name'.
Please note, fqname will not expand the right hand side of a
record (ie, CNAME, SOA, MX, etc). The user must expand these values via
the above method.
- ttl_to_int
- Takes a single parameter, a string representing a valid record TTL.
Returns an integer representing the number of seconds the TTL
represents. Note, this does not take into account any leap-years,
leap-seconds, DST changes, etc. It is simply the count of the number of
seconds in the specified period of time.
- new_serial
- "new_serial()" incriments the Zone
serial number. It will generate a date-based serial number. Or you can
pass a positive number to add to the current serial number.
Examples:
$zonefile->new_serial();
# generates a new serial number based on date:
# YYYYmmddHH format, incriments current serial
# by 1 if the new serial is still smaller
$zonefile->new_serial(50);
# adds 50 to the original serial number
- output
- "output()" returns the new zone file
output as a string. If you wish your output formatted differently, you can
pass the output of "dump()" to your
favourite templating module.
- last_parse_error_count
- Returns a count of the number of unparsable lines from the last time a
zone file was parsed. If no zone file has been parsed yet, returns 0.
If you want to be sure that a zone file was parsed completely
and without error, the return value of this method should be checked
after the constructor is called (or after a call to _parse).
- on_unparseable_line
- "on_unparseable_line()" is an accessor
method for the callback used when an unparseable line is encountered while
parsing a zone file. If not set, DNS::ZoneParse will
"croak" when an unparsable line is
encountered, but will continue to parse the file. Each time an unparsable
line is encountered, an internal counter is incrememnted. See
"last_parse_error_count" for details.
The callback is passed four parameters, a reference to the
DNS::ZoneParse object which is doing the parsing, the text of the line
that is unable to be parsed, the text of the reason the line could not
be parsed, and the text of the last successfully parsed line.
If you want to abort parsing when an unparsable line is found,
call "die" from within your callback
and catch that die with an eval block around the DNS::ZoneParse
constructor (or call to _parse).
The method takes a single optional parameter, a code reference
to the function that will be called when an unparsable line is reached.
Returns a reference to the last callback. If passed an undefined value,
a reference to the current callback is returned. If passed any other
value, undef is returned.
This script will print the A records in a zone file, add a new A record for the
name "new" and then return the zone file.
use strict;
use DNS::ZoneParse;
my $zonefile = DNS::ZoneParse->new("/path/to/zonefile.db");
print "Current A Records\n";
my $a_records = $zonefile->a();
foreach my $record (@$a_records) {
print "$record->{name} resolves at $record->{host}\n";
}
push (@$a_records, { name => 'new', class => 'IN',
host => '127.0.0.1', ttl => '' });
$zonefile->new_serial();
my $newfile = $zonefile->output();
This script will convert a DNS Zone file to an XML file using
XML::Simple.
use strict;
use DNS::ZoneParse;
use XML::Simple;
my $zonefile = DNS::ZoneParse->new("/path/to/zonefile.db");
my $new_xml = XMLout($zonefile->dump,
noattr => 1,
suppressempty => 1,
rootname => $zonefile->origin);
The DNS::ZoneParse API may change in future versions. At present, the parsing is
not as strict as it should be and support for $ORIGIN
and $TTL is quite basic. It would also be nice to
support the "INCLUDE" statement.
Furthermore, parsing large zone files with thousands of records can use lots
of memory - some people have requested a callback interface.
I can squash more bugs with your help. Please let me know if you spot something
that doesn't work as expected.
You can report bugs via the CPAN RT:
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=DNS-ZoneParse>
If possible, please provide a diff against
t/dns-zoneparse.t and t/test-zone.db that demonstrates the
bug(s).
Other modules with similar functionality:
Net::DNS::ZoneParser, Net::DNS::ZoneFile, DNS::ZoneFile
Maintainers: Mike Schilli (m@perlmeister.com), John Eaglesham (perl@8192.net).
Bug queue:
http://rt.cpan.org/Public/Dist/Display.html?Name=DNS-ZoneParse
DNS::ZoneParse is free software which you can redistribute and/or modify under
the same terms as Perl itself.
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