#!/bin/bash

#
# Run the OpenVPN server normally
#

if [ "$DEBUG" == "1" ]; then
  set -x
fi

set -e

cd $OPENVPN

# Build runtime arguments array based on environment
USER_ARGS=("${@}")
ARGS=()

IPTABLES="iptables-nft"

# Checks if ARGS already contains the given value
function hasArg {
    local element
    for element in "${@:2}"; do
        [ "${element}" == "${1}" ] && return 0
    done
    return 1
}

# Adds the given argument if it's not already specified.
function addArg {
    local arg="${1}"
    [ $# -ge 1 ] && local val="${2}"
    if ! hasArg "${arg}" "${USER_ARGS[@]}"; then
        ARGS+=("${arg}")
        [ $# -ge 1 ] && ARGS+=("${val}")
    fi
}

# set up iptables rules and routing
# this allows rules/routing to be altered by supplying this function
function setupIptablesAndRouting {
      $IPTABLES -t nat -C POSTROUTING -s $VPN_CIDR_RANGE -o $OVPN_NATDEVICE -j MASQUERADE 2>/dev/null || {
      $IPTABLES -t nat -A POSTROUTING -s $VPN_CIDR_RANGE -o $OVPN_NATDEVICE -j MASQUERADE
    }
    for i in "${OVPN_ROUTES[@]}"; do
          $IPTABLES -t nat -C POSTROUTING -s "$i" -o $OVPN_NATDEVICE -j MASQUERADE 2>/dev/null || {
          $IPTABLES -t nat -A POSTROUTING -s "$i" -o $OVPN_NATDEVICE -j MASQUERADE
        }
    done
}


addArg "--config" "$OPENVPN/openvpn.conf"

VPN_CIDR_RANGE="172.16.10.0/24"

# When using --net=host, use this to specify nat device.
OVPN_NATDEVICE=eth0

mkdir -p /dev/net
if [ ! -c /dev/net/tun ]; then
    mknod /dev/net/tun c 10 200
fi

if [ -d "$OPENVPN/ccd" ]; then
    addArg "--client-config-dir" "$OPENVPN/ccd"
fi

# Setup NAT forwarding if requested
setupIptablesAndRouting

echo "Running 'openvpn ${ARGS[@]} ${USER_ARGS[@]}'"
exec openvpn ${ARGS[@]} ${USER_ARGS[@]}