tb_tunnel_direction_downstream
if (tb_tunnel_direction_downstream(tunnel))
downstream = tb_tunnel_direction_downstream(tunnel);
if (tb_tunnel_direction_downstream(tunnel)) {
if (tb_tunnel_direction_downstream(tunnel)) {
if (tb_tunnel_direction_downstream(tunnel)) {
if (tb_tunnel_direction_downstream(tunnel)) {
if (tb_tunnel_direction_downstream(tunnel)) {
if (tb_tunnel_direction_downstream(tunnel)) {
if (tb_tunnel_direction_downstream(tunnel))
if (tb_tunnel_direction_downstream(tunnel))