#!/bin/bash

# BSD 2-Clause License

# Copyright (c) 2020, Supreeth Herle
# All rights reserved.

# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:

# 1. Redistributions of source code must retain the above copyright notice, this
#    list of conditions and the following disclaimer.

# 2. Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.

# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

set -x
RUNTIME=${1:-rtpengine}

if lsmod | grep xt_RTPENGINE || modprobe xt_RTPENGINE; then
	echo "rtpengine kernel module already loaded."
else
	modprobe xt_RTPENGINE
fi

GW_IP=${GW_IP:-"$(host -4 $GW_HOSTNAME |awk '/has.*address/{print $NF; exit}')"}
export GW_IP
echo "GW_IP: $GW_IP"

INTERFACE_IP=${INTERFACE_IP:-"$(host -4 $RTPENGINE_HOSTNAME |awk '/has.*address/{print $NF; exit}')"}
export INTERFACE_IP
echo "INTERFACE_IP: $INTERFACE_IP"

LISTEN_NG=${INTERFACE_IP}:2223
export LISTEN_NG
echo "LISTEN_NG: $LISTEN_NG"

if [ -z "$GW_IP" ]
then
	echo "Unable to resolve some IPs... restarting"
	exit 1
fi

# Populate options of the rtpengine cli command
[ -z "$INTERFACE_IP" ] && INTERFACE_IP="$(awk 'END{print $1}' /etc/hosts)"
[ -z "$TABLE" ] && TABLE="0"
[ -z "$LISTEN_NG" ] && LISTEN_NG="$(awk 'END{print $1}' /etc/hosts):2223"
[ -z "$PORT_MIN" ] && PORT_MIN="30000"
[ -z "$PORT_MAX" ] && PORT_MAX="40000"
[ -z "$TOS" ] && TOS="184"
[ -z "$PIDFILE" ] && PIDFILE="/run/ngcp-rtpengine-daemon.pid"

LISTEN_CLI="$(awk 'END{print $1}' /etc/hosts):9901"

OPTIONS=""
OPTIONS="$OPTIONS --interface=$INTERFACE_IP --listen-ng=$LISTEN_NG --listen-cli=$LISTEN_CLI --pidfile=$PIDFILE --port-min=$PORT_MIN --port-max=$PORT_MAX "
OPTIONS="$OPTIONS --table=$TABLE  --tos=$TOS --foreground"

if test "$NO_FALLBACK" = "yes" ; then
	OPTIONS="$OPTIONS --no-fallback"
fi

# Sync docker time
#ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

set +e
if [ -e /proc/rtpengine/control ]; then
	echo "del $TABLE" > /proc/rtpengine/control 2>/dev/null
fi
# Freshly add the iptables rules to forward the udp packets to the iptables-extension "RTPEngine":
# Remember iptables table = chains, rules stored in the chains
# -N (create a new chain with the name rtpengine)
iptables -N rtpengine 2> /dev/null

# -D: Delete the rule for the target "rtpengine" if exists. -j (target): chain name or extension name 
# from the table "filter" (the default -without the option '-t') 
iptables -D INPUT -j rtpengine 2> /dev/null
# Add the rule again so the packets will go to rtpengine chain after the (filter-INPUT) hook point.
iptables -I INPUT -j rtpengine
# Delete and Insert a rule in the rtpengine chain to forward the UDP traffic    
iptables -D rtpengine -p udp -j RTPENGINE --id "$TABLE" 2>/dev/null
iptables -I rtpengine -p udp -j RTPENGINE --id "$TABLE"
iptables-save > /etc/iptables.rules

# The same for IPv6
ip6tables -N rtpengine 2> /dev/null
ip6tables -D INPUT -j rtpengine 2> /dev/null
ip6tables -I INPUT -j rtpengine
ip6tables -D rtpengine -p udp -j RTPENGINE --id "$TABLE" 2>/dev/null
ip6tables -I rtpengine -p udp -j RTPENGINE --id "$TABLE"
ip6tables-save > /etc/ip6tables.rules

# Add static route to route traffic back to UE as there is not NATing
ip r add ${APN_IMS_SUBNET} via ${GW_IP}

set -x

exec $RUNTIME $OPTIONS
