#!/bin/sh
#
# Marta Carbone
# Copyright (C) 2009 Universita` di Pisa
# $Id$
#
# This script is the frontend to be used with
# the vsys system.
# It allows to configure dummynet pipes and queues.
# In detail it:
# - get user input
# - send command to the vsys input pipe
# - wait a bit
# - get the reply from the output vsys pipe
# - show the output to the user
# 
# A simple usage is:
# ./netconfig -p 9898 <dummynet configuration parameters>
# mandatory fields are the port to be configured
# and dummynet configuration parameters

PIPE_IN=/vsys/ipfw-be.in
PIPE_OUT=/vsys/ipfw-be.out
LOGFILE=/tmp/netconfig.log

SED=/bin/sed		# used to extract the profile name
DEBUG=0			# 0 disable debug messages
prog=$0			# this program

# Print the first argument and exit
abort()
{
	echo "$1"; exit 1
}

# if $DEBUG is enabled, print a debug message
# $1 the message to print
debug()
{
	[ "${DEBUG}" != "0" ] && echo "$1" >> ${LOGFILE}
}

# print the usage and exit
help()
{
	cat << EOF
Usage: $prog -p port [-U] [-t timeout[STRING]] ipfw_configuration_parameters \n
       $prog ipfw show	\n
       $prog pipe show	\n

  -h show help \n
  -p specify the port to configure \n
  -d delete specified rules and pipes \n
  -t specify the timeout. STRING can be "1minute" or "4hours" (default 1 hour) \n

   ipfw configuration parameters (mandatory) \n
	   extra-delay <filename> bw <value> delay <value> proto... plr... \n

   ipfw show show the ipfw ruleset
   ipfw pipe show the configured pipes
EOF
	exit 0
}

# parse input line and fill missing fields
parse_input()
{
	# counters used to check if at least
	# two ipfw configuration parameters are present
	local OPT_ARGS=2	# optional (timeout)
	local MAND_ARGS=2	# mandatory (port)

	[ -z "$1" ] && help;

	while getopts ":hdp:t:" opt; do
		case $opt in
		h | \?) help;;
		p) PORT=$OPTARG;;
		d) DELETE=1;;
		t) TIMEOUT=$OPTARG;;
		esac
	done

	# check for mandatory arguments
	[ -z ${PORT} ] && abort "a port value is mandatory";

	# the default value for the timeout is 1H
	if [ -z ${TIMEOUT} ]; then
		TIMEOUT="1hour"
		OPT_ARGS=$((${OPT_ARGS}-2))
	fi

	# check for deletion flag
	if [ -z ${DELETE} ]; then
		DELETE=0
	else
		# if d is present configuration is not required
		MAND_ARGS=$((${MAND_ARGS}-2))
	fi

	# compute residue argument, we need at least 2 
	# mandatory arguments (for ipfw), exit on error
	# debug "Passed args $# Mandatory ${MAND_ARGS} Optional ${OPT_ARGS} Extra $(($#-${MAND_ARGS}-${OPT_ARGS}))"
	if [ $(($#-${MAND_ARGS}-${OPT_ARGS})) -lt 2 ]; then
		help
	fi
}

# the backend expects lines in the format:
# ipfw
# pipe
# port timeout configuration_string
# main starts here

	# allow ipfw show and ipfw pipe show commands
	if [ x$1 = x"ipfw" ]; then
		echo "received" $1
		echo "ipfw" >> ${PIPE_IN}
		cat ${PIPE_OUT}
		exit 0;
	else if [ x$1 = x"pipe" ]; then
		echo "pipe" >> ${PIPE_IN}
		cat ${PIPE_OUT}
		exit 0;
	fi
	fi

	# parse the input
	parse_input $*
	shift $((${OPTIND}-1));

	# print debug
	debug "PORT ${PORT}"
	debug "DELETE ${DELETE}"
	debug "TIMEOUT ${TIMEOUT}"
	debug "PIPE_CONFIGURATION $*"

	# format CMD as expected by the backend script
	CMD="${PORT} ${TIMEOUT} ${DELETE} $*";

	# send the command
	debug "Sending: ${CMD}"
	echo ${CMD} >> ${PIPE_IN}

	cat ${PIPE_OUT}