ovs_key_attr_size
+ nla_total_size(ovs_key_attr_size()) /* OVS_PACKET_ATTR_KEY */
len += nla_total_size(ovs_key_attr_size());
len += nla_total_size(ovs_key_attr_size());
len += nla_total_size(ovs_key_attr_size());
size_t ovs_key_attr_size(void);