CAKE_FLOW_NAT_FLAG
flow_mode &= ~CAKE_FLOW_NAT_FLAG;
flow_mode |= CAKE_FLOW_NAT_FLAG *
flow_mode = ((flow_mode & CAKE_FLOW_NAT_FLAG) |
!!(flow_mode & CAKE_FLOW_NAT_FLAG)))
bool nat_enabled = !!(flow_mode & CAKE_FLOW_NAT_FLAG);