#!/usr/bin/perl -w
use strict;

my %iph;

while(<>) {
	chomp;
	add_rule($_);
	flush_rules();
}

sub add_rule {
	my $ip = $_[0];
	system("/usr/sbin/iptables -A INPUT -i eth0 -s $ip -j DROP\n");
	$iph{$ip} = time();

}

sub flush_rules {
	my $now = time();
	foreach (keys %iph) {	    # CHANGE THIS
		if ($now - $iph{$_} > 3) { # If entry is > 3 seconds old
			print("Deleting: $_\n");
			delete_rule_by_ip($_);
			delete($iph{$_});
		}
	}
}

sub delete_rule_by_ip {
	my $ip = $_[0];
	my @rules = `/usr/sbin/iptables -n --line-numbers -L`;

	foreach (@rules) {
		next unless /$ip/;
		my $num = (split(/\s+/, $_))[0];
		return unless $num;
		system("/usr/sbin/iptables -D INPUT $num");
	}
}