int dp_send_flow_expired(struct datapath *, struct sw_flow *,
enum ofp_flow_expired_reason);
int dp_send_error_msg(struct datapath *, const struct sender *,
int dp_send_flow_expired(struct datapath *, struct sw_flow *,
enum ofp_flow_expired_reason);
int dp_send_error_msg(struct datapath *, const struct sender *,