fix: Port forwarding (#530)

getPorts() {

  local list=$1

  local args=""

  local vnc="5900"

  list="${list//,/ }"

  list="${list## }"

  list="${list%% }"

  if [[ "${DISPLAY,,}" == "vnc" ]] && [[ "$list" != *"$vnc"* ]]; then

    if [ -z "$list" ]; then

      list="$vnc"

    else

      list="$list $vnc"

    fi

    [ -z "$list" ] && list="$vnc" || list="$list,$vnc"

  fi

  if [ -n "$list" ]; then

    if [[ "$list" != *" "* ]]; then

      args=" ! --dport $list"

  [ -z "$list" ] && return 0

  if [[ "$list" != *","* ]]; then

    echo " ! --dport $list"

  else

      args=" -m multiport ! --dports "

      for port in $list; do

        args="${args}${port},"

      done

      args="${args%?}"

    fi

    echo " -m multiport ! --dports $list"

  fi

  echo "$args"

  return 0

}