#!/usr/bin/env perl

use strict;
use warnings;
use Data::Dumper;
use 5.010;

# declare
my @net_configs;

my @data = <DATA>;

foreach my $confLine (@data) {

    # find start of a network, push to array
    if ( $confLine =~ /<ip4-network range/ )
    {
        say "Found start of network !";
        push( @net_configs, $confLine );
    }

    # push other network lines onto array
    elsif ( @net_configs )
    {
        push( @net_configs, $confLine );

        # check for end of a network
        if ( $confLine =~ /<\/ip4-network>/ )
        {
            say "Found end of network !";

            if ( grep /dhcp-range/, @net_configs )
            {
                say "Found a dhcp-range !";
                foreach my $net_config (@net_configs)
                {
                    print $net_config;
                }
            }
        @net_configs = undef;
        }
    }
}

__DATA__
<data>
    <configuration name="Test">
        <ip4-network range="10.2.2.0/24">
            <dhcp-range range="10.2.2.50 - 10.2.2.99"/>
            <dhcp-service-option name="next-server" value="10.1.2.3"/>
            <dhcp-client-option name="tftp-server-name" code="66" value="10.1.2.3"/>
            <dhcp-client-option name="boot-file-name" code="67" value="boot.com"/>
        </ip4-network>
        <ip4-network range="10.2.4.0/24">
            <ip4-address address="10.2.4.2" name="10.2.4.2" state="dhcp-reserved" mac="AA-BB-CC-DD-EE-FF"/>
            <dhcp-service-option name="next-server" value="10.1.2.3"/>
            <dhcp-client-option name="tftp-server-name" code="66" value="10.1.2.3"/>
            <dhcp-client-option name="boot-file-name" code="67" value="boot.com"/>
        </ip4-network>
        <ip4-network range="192.168.1.0/24">
            <dhcp-service-option name="next-server" value="10.1.2.3"/>
            <dhcp-client-option name="tftp-server-name" code="66" value="10.1.2.3"/>
            <dhcp-client-option name="boot-file-name" code="67" value="boot.com"/>
        </ip4-network>
    </configuration>
</data>

##</code><code>##

Found start of network !
Found end of network !
Found a dhcp-range !
        <ip4-network range="10.2.2.0/24">
            <dhcp-range range="10.2.2.50 - 10.2.2.99"/>
            <dhcp-service-option name="next-server" value="10.1.2.3"/>
            <dhcp-client-option name="tftp-server-name" code="66" value="10.1.2.3"/>
            <dhcp-client-option name="boot-file-name" code="67" value="boot.com"/>
        </ip4-network>
Found start of network !
Found end of network !
Use of uninitialized value $_ in pattern match (m//) at zTweak.pl line 32, <DATA> line 21.
Found start of network !
Found end of network !
Use of uninitialized value $_ in pattern match (m//) at zTweak.pl line 32, <DATA> line 21.