#!/usr/bin/perl
#written by Shunsuke Sakai(2000/06/06)

&dateget;

############ get the IP address and MAC address ##############

$/="}\n";
$\="\n";
open(LOG,'</var/dhcp/dhcpd.leases');
while($log=<LOG>){
        @log=split(/\n/,$log);
        @log[3]=~ s/\shardware\sethernet\s//;
        @log[3]=~ s/;//;
        @ip=split(/ +/,@log[0]);
        @date=split(/ +/,@log[2]);
        $lease{@log[3]}=@ip[1];
        $lease2{@log[3]}=@date[2];
}

############## get the authorized MAC address ###############

$/="\n";
open(CLIENT,'</etc/dhcp.client');
while($client=<CLIENT>){
        chop $client;
        if($client=~ m/[0-9a-f][0-9a-f]:[0-9a-f][0-9a-f]:[0-9a-f][0-9a-f]:[0-9a-
f][0-9a-f]:[0-9a-f][0-9a-f]:[0-9a-f]/){
                @client=(@client,$client);
        }
}

############## check the unauthorized MAC address ###############

open(LOG,'>/var/dhcp/dhcp.unauth');
$regist = 'no';
foreach $address (keys %lease){
        foreach $client (@client){
                if($address eq $client){
                        $regist = 'yes';
                }
        }
        if($regist ne 'yes'){
                $number = $number +1;
                print LOG $lease{$address},' - ',$lease2{$address},' - ',$addres
s;
        }
        $regist = 'no';
}
print LOG "\n",$number,' persons are unauthorized !!','(',$year,'/',$month,'/',$
today,')';
close(LOG);
close(CLIENT);
close(LOG);

###############   get the yesterday's date   ############################

sub dateget{
        system('date "+%Y %m %d" > /var/log/ftp/datefile');
        open(DATE,"< /var/log/ftp/datefile");
        while($date=<DATE>){
                chop $date;
                @line=split(/ +/,$date);
                $year=$line[0];
                $month=$line[1];
                $today=$line[2];
        }
        close(DATE);
}