struct {
uint64_t l2_len:7; /**< L2 (MAC) Header Length. */
uint64_t l3_len:9; /**< L3 (IP) Header Length. */
+ uint64_t l4_len:8; /**< L4 Header Length. */
+ uint64_t tso_segsz:16; /**< TCP TSO segment size */
uint64_t outer_l2_len:8; /**< outer L2 Header Length */
uint64_t outer_l3_len:16; /**< outer L3 Header Length */
};