code: func checkNfSocket() error {
  	fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW, syscall.NETLINK_NETFILTER)
  	if err != nil {
  		return err
  	}
  	syscall.Close(fd)
  	return nil
  }
docs: // API check on required nf_conntrack* modules (nf_conntrack, nf_conntrack_netlink)