#!/usr/bin/perl
use strict 'subs';

# 0.50 -  Written by Douglas Rand <rand@aero.und.edu>
# 0.60 - Modified by Patrick Ryan 12-1-1999 <pryan@cs.washington.edu>
## Line "foreach $i (ip2int($begin) .. ip2int($end)) {" replaced by
## "for ($i = ip2int($begin), $j = ip2int($end); $i < $j; $i++) {"
# 0.70 - Modified by Leif Sawyer 12-10-1999 <leif@gci.net>
## patches to ignore scopes with no active leases
## patches to automatically format for HTML based on environment
# 0.80 - Modified by Simon Barnes 1/19/2000 <barnes@gatwick.geco-prakla.slb.com>
## patches to allow single-host ranges
# 0.82 - Some cleanups, Leif Sawyer 3/10/2000

$Version = "0.82";

require "timelocal.pl";
require "newgetopt.pl";
use Time::ParseDate;

&NGetOpt("detail:s");
print "getopt\n" if defined($opt_detail);

@WDays = ("Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat");
@MNames = ("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec");

$PathLeases = "/var/dhcpd/dhcpd.leases";
$PathConfig = "/etc/dhcpd/dhcpd.conf";

my(%IP);
my($DEBUG) = 0;

$IPPat = "[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}";

$date=`/bin/date`; chop $date;

my($HTML);
$HTML = (defined($ENV{"REQUEST_METHOD"}) && $ENV{"REQUEST_METHOD"} ne "")?1:0;

print "Content-type: text/plain\n\n" if $HTML;

print "DHCP Lease stats for $date\n";

open(CONFIG, "<$PathConfig") || die "Canot open $PathConfig: $!\n";
open(LEASES, "<$PathLeases") || die "Cannot open $PathLeases: $!\n";

my($subnet,$netmask);

while(<CONFIG>) {
	chop;

# print "$_\n" if $DEBUG;

    if(/^\s*subnet\s+($IPPat)\s+netmask\s+($IPPat)/) {
print "subnet = $1, netmask = $2\n" if $DEBUG;
	$subnet = $1;
	$netmask = $2;
	$network{$subnet} = 1;
    }
    if (/^\s*range\s+/) {
	if(/^\s*range\s+($IPPat)\s+($IPPat)\s*;\s*$/) {
	    $begin = $1, $end = $2;
	} elsif (/^\s*range\s+($IPPat)\s*;\s*$/) {
		$begin = $1, $end = $1;
	} else {
		die "range found, but can't parse range data:\n$_\n$!";
	}
	for ($i = ip2int($begin), $j = ip2int($end); $i <= $j; $i++) {
#print "i=$i, int2ip->" . int2ip($i) . ", subnet=$subnet\n" if $DEBUG;
	    $range{int2ip($i)} = $subnet;
	    $IP{$subnet}{$i} = 1;
	}
    }
}

while(<LEASES>) {
    $ip = $1 if /^lease (\d+\.\d+\.\d+\.\d+) \{$/;
    $start{$ip} = $1 if /^\tstarts \d (\d+\/\d+\/\d+ \d+:\d+:\d+);$/;
    $end{$ip} = $1 if ((/^\tends \d (\d+\/\d+\/\d+ \d+:\d+:\d+);$/) || (/^\tends (never);$/));
    $hwtype{$ip} = $1, $hwaddress{$ip} = $2 if /^\thardware (ethernet|token-ring) ([0-9a-f]+:[0-9a-f]+:[0-9a-f]+:[0-9a-f]+:[0-9a-f]+:[0-9a-f]+);/;
    $abandoned{$ip} = 1 if /^\tabandoned;$/;
    $hostname{$ip} = $1 if/^\tclient-hostname \"(.*)\";$/;
}

$time = time();
print "IP Address      Status         Lease Begin            Lease End          HW Address\n" if defined($opt_detail);
foreach $ip (sort ipsort keys %range) {
    $net = $range{$ip};
    $Total{$net}++;
    if($start{$ip}) {
	$startSecs = parsedate("$start{$ip} GMT");
	if ($end{$ip} != "never") {
	    $endSecs = parsedate("$end{$ip} GMT");
	    $end = &mktime($endSecs);
	} else {
	    $endSecs = "never";
	    $end = "never";
	}
	$start = &mktime($startSecs);
	if(($endSecs >= $time) || ($endSecs eq "never")) {
	    $status = "Active";
	    $Active{$net}++ unless $abandoned{$ip};
	}
	else {
	    $status = "Expired";
	    $Expired{$net}++ unless $abandoned{$ip};
	    $Available{$net}++ unless $abandoned{$ip};
	}
    }
    else {
	$start = "";
	$end = "";
	$status = "Unused";
	$Unused{$net}++;
	$Available{$net}++ unless $abandoned{$ip};
    }
    if($abandoned{$ip}) {
	$status = "Abandoned";
	$Abandoned{$net}++;
    }
    printf("%-15s %-9s  %19s  %19s  %17s\n",
	   $ip, $status, $start, $end, $hwaddress{$ip}) if defined($opt_detail);
}

if(!defined($opt_detail)) {
    print "Network            Active    Available    Abandoned    Total\n";
    foreach $net (sort ipsort keys %network) {
print "net = $net, Active = $Active{$net}, total = $Total{$net}\n" if $DEBUG;
		printf("%-15s  %4d/%3.0f%%   %4d/%3.0f%%    %4d/%3.0f%%     %4d\n",
	       $net, $Active{$net}, ($Total{$net}>0?($Active{$net} / $Total{$net}):0) * 100.0,
	       $Available{$net}, ($Total{$net}>0?($Available{$net} / $Total{$net}):0) * 100.0,
	       $Abandoned{$net}, ($Total{$net}>0?($Abandoned{$net} / $Total{$net}):0) * 100.0,
	       $Total{$net}) if ($Active{$net} > 0);
    }
}

print "\n";

sub mktime {
    my($secs) = shift;
    my($time, $year, $month, $day, $hour, $minute, $seconds, $wday);

    ($second, $minute, $hour, $day, $month, $year, $wday) = localtime($secs);
    $time = sprintf("%s %s %2d %2d:%02d:%02d",
		    $WDays[$wday], $MNames[$month], $day, $hour, $minute, $second);
    return($time);
}

sub ip2int {
    my($ip) = shift;
    my($number) = 0;

    $number = $1 * 256 * 256 * 256 + $2 * 256 * 256 + $3 * 256 + $4
	if $ip =~ /^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$/;
    return $number;
}



sub int2ip {
    my($number) = shift;
    my($ip);

    $ip = ($number & 0xff000000) / (256 * 256 * 256);
    $ip .= "." . ($number & 0x00ff0000) / (256 * 256);
    $ip .= "." . ($number & 0x0000ff00) / (256);
    $ip .= "." . ($number & 0x000000ff);
    return $ip;
}

sub ipsort {
    my(%A, %B);
    
    $A[0] = $1, $A[1] = $2, $A[2] = $3, $A[3] = $4
	if $a =~ /^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$/;
    $B[0] = $1, $B[1] = $2, $B[2] = $3, $B[3] = $4
	if $b =~ /^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$/;
    return $A[0] <=> $B[0] if $A[0] != $B[0];
    return $A[1] <=> $B[1] if $A[1] != $B[1];
    return $A[2] <=> $B[2] if $A[2] != $B[2];
    return $A[3] <=> $B[3];
}