#!/bin/sh
#
#	nopttimeout script for IRLP v0.2 - Robert Pectol (kk7av)
#	Overcomes the PTT lockout timer by momentarily interrupting
#	the incoming audio data stream whhile connected to a node
#	or reflector that has long periods of TX activity with no
#	breaks.  Useful for monitoring Space Shuttle audio, etc.
#
#
#	* NOTE *
#	If the method, as specified below, is set to, 'packet',
#	then this script requires that your /etc/sudoers file
#	contains the following line:
#
#		repeater ALL= NOPASSWD: /sbin/iptables
#
#	This MUST be accomplished by editing /etc/sudoers with
#	the, 'visudo' command as user, root.
#################################################################

################################
#  USER CONFIGURABLE SETTINGS  #
################################

# How often to interrupt the incoming audio stream.  This
# is in seconds (ex: 180 is 3 minutes)
interrupt_interval="180"

# How long to interrupt the incoming audio stream.  This is
# in micro-seconds (ex: 1000000 is one second)
interrupt_time="1000000"

# Method used to interrupt the audio stream.  Use, 'packet'
# to interrupt incoming packets that cary the audio payload.
# Use, 'other' to interrupt ispeaker.  Either method works
# but the packet method is preferred since it's a cleaner
# way of accomplishing the interruption.
method="packet"

# If the method above is specified as, 'packet', then this
# specifies the port range to interrupt
# (set this to '2074:2093' for IRLP)
port="2074:2093"

# Feedback during script execution (set to either, 'yes' or, 'no')
verbose="no"

# Lockfile location (the default is usually fine)
lockfile="/tmp/nopttimeout.lock"

##############################
#  END USER CONFIG SETTINGS  #
##############################

# test for/create lockfile
if [ -e $lockfile ]; then
	echo "lockfile exists!  exiting..."
	exit 1
else
	touch $lockfile
fi

# ensure script is run as repeater user
if [ `/usr/bin/whoami` != "repeater" ] ; then
        exit 1
fi
# ensure the environment file has been sourced
if [ "$RUN_ENV" != "TRUE" ] ; then
        . /home/irlp/custom/environment
fi

# exit cleanly when interrupted
trap stop INT TERM EXIT

# show user settings (if verbose is set to, 'yes')
if [ "$verbose" == "yes" ]; then
	clear
	echo "Currently running script in verbose mode.  Although"
	echo "it's a handy way to see what the script is doing,"
	echo "especially for debug purposes, it's not meant to"
	echo "be left that way.  Under, 'normal' circumstances,"
	echo "it's best to set the verbose option to, 'no' in"
	echo "the USER CONFIGURABLE SETTINGS at the top of the"
	echo "script.  Resuming momentarily..."
	echo ""
	sleep 10
	echo "Interrupt interval: $interrupt_interval (seconds)"
	echo "Interrupt time: $interrupt_time (micro-seconds)"
	if [ "$method" == "packet" ]; then
		echo "Method: block packets"
		echo "Port(s) to interrupt: $port"
	else
		echo "Method: manipulate ispeaker"
	fi
	echo "######################################"
	echo ""
	sleep 3
fi
interrupt_interval=$(($interrupt_interval + 1))
mainloop()
{
	while true; do
		count=0
		while [ $count -lt $interrupt_interval ]; do
			sleep 1
			if [ -f $LOCAL/.nopttimeout ]; then
				if [ "$verbose" == "yes" ]; then
					echo "$0 disabled by $LOCAL/.nopttimeout, exiting..."
				fi
				stop
			fi
			count=$(($count + 1))
			remaining=$(($interrupt_interval - $count))
			if [ "$verbose" == "yes" ]; then
				clear
				echo "$remaining seconds until interruption..."
			fi
		done
		if [ "$verbose" == "yes" ]; then
			echo "breaking connection for $interrupt_time uSec..."
		fi
		if [ "$method" == "packet" ]; then
			sudo /sbin/iptables -I INPUT -p udp --dport $port -j DROP
		else
			killall ispeaker > /dev/null 2>&1
		fi
		usleep $interrupt_time
		if [ "$verbose" == "yes" ]; then
			echo "enabling connection..."
		fi
		if [ "$method" == "packet" ]; then
			sudo /sbin/iptables -D INPUT -p udp --dport $port -j DROP
		else
			$SCRIPT/sfswrapper
		fi
	done
}
stop ()
{
	if [ "$verbose" == "yes" ]; then
		echo "$0 - exiting..."
	fi
	if [ "$method" == "packet" ]; then
		sudo /sbin/iptables -D INPUT -p udp --dport $port -j DROP > /dev/null 2>&1
	else
		$SCRIPT/sfswrapper
	fi
	rm -f $LOCAL/.nopttimeout > /dev/null 2>&1
	rm -f $lockfile > /dev/null 2>&1
	exit 0
}
mainloop
exit 1