#!/usr/bin/perl
#
# Filename: timeout.pl
#
# Script (c) Feb 17, 1998 by FMP Computer Services
# Terms of the GNU GENERAL PUBLIC LICENSE apply
# see <http://www.gnu.org/copyleft/gpl.html>
# Contact fmouse@fmp.com for details.
#
# Run out of cron every 5 minutes. Looks at /proc/net/dev 
# to monitor packet traffic.  Requires setup of session file 
# in ip-up.  Requires perl v5.
# 
# Run manually with -t option to force session length timeout
# or with -i option to force inactivity timeout.
# Syntax: timeout.pl -i|-t ifname
# ifname = ppp0, ppp1, ppp2, etc.
#
# Things that can (or should) be modified ....
#

# Session and pid directory
$piddir = "/var/run";

# Shut down session after this many minutes of inactivity
$itime = 25;

# Shut down session unconditionally after this many minutes online
$utime = 240;

# Should I send email when a session gets killed?
$notify = 1;	# Set to 1 to notify, 0 for no notification

# If I notify, to whom should I send email when a session gets killed?
$sysadmin = "root\@anyserver.com";

# If I notify, what's my mailer?
$mailer = "/usr/sbin/sendmail -t";

# --------------------------------------------------------------------
# Nothing below this should need modifying -- conditional on line 76
# can be modified to select inactivity timeout criteria
# --------------------------------------------------------------------
use Getopt::Std;
# Parse command line arguments
getopts('it');
$cmd_if = $ARGV[0];

# Scan for session files.
opendir (VARRUN, $piddir);
@sessionfiles = grep (/^ppp[0-9]+\.session/, readdir(VARRUN));
closedir (VARRUN);

foreach $file (@sessionfiles) {
	open (SESSION, "${piddir}/$file") || exit 1;
	$session = <SESSION>;
	($who, $pid, $stime, $ctime, $rspackets, $xspackets) = split /\t/, $session;
	close SESSION;
	
	open (NETSTAT, "/proc/net/dev");
	<NETSTAT>;	# toss out header lines
	<NETSTAT>;
	while (<NETSTAT>) {
		($ifname, $rpackets, $rerrs, $rdrop, $rfifo, 
$rframe, $xpackets, $xerrs, $xdrop, $xfifo, $xcolls, $xcarrier) = split;
		last if $ifname eq $iface.":";
	}
	# It's decision time!
	$curtime = time;			# Current time
	$session_time = $curtime - $stime;	# Total time online
	$check_time = $curtime - $ctime;	# Inactivity time

	# Check to see if total time online has been exceeded
	if ((($file eq $cmd_if.".session") && $opt_t) || 
($session_time > ($utime * 60))) {
		kill "INT", ($pid);
		&notify("Overtime") if $notify;
		exit 0;

	# If still within total time, check for inactivity
	# This expression can be changed to suit your needs.  Here,
	# inactivity is indicated by a lack of both incoming and outgoing
	# traffic.
	} elsif ((($file eq $cmd_if.".session") && $opt_i) || 
(($rspackets == $rpackets) && ($xspackets == $xpackets))) {
		if ($check_time > ($itime * 60)) {
			kill "INT", ($pid);
			&notify("Inactivity") if $notify;
		}
		exit 0;
	}
	
	else {
		open (SESSION, ">${piddir}/$file");
		print SESSION "$who\t$pid\t$stime\t$curtime\t$rpackets\t$xpackets";
		close (SESSION);
	}
}

sub notify {
	local($message) = @_;
	($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime $stime;
	@months = ("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec");
	@weekdays = ("Sun","Mon","Tue","Wed","Thu","Fri","Sat");
	$thismonth = $months[(localtime $stime)[4]];
	$thisday = $weekdays[(localtime $stime)[6]];
	
	open (MAILOUT, "| $mailer");
	print MAILOUT <<EOF;
To: $sysadmin
From: PPP.Timeout.script
Subject: Timeout Due to $message

Timeout Due to $message

Session Owner:    $who
Session Started:  $thisday $thismonth $mday $hour:$min
EOF
	($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime;
	$thismonth = $months[(localtime)[4]];
	$thisday = $weekdays[(localtime)[6]];
	print MAILOUT <<EOF;
Session Ended:    $thisday $thismonth $mday $hour:$min

EOF
	close MAILOUT;
}