#define TNL_F_TOS_INHERIT (1 << 4) /* Inherit the ToS from the inner packet. */
#define TNL_F_TTL_INHERIT (1 << 5) /* Inherit the TTL from the inner packet. */
#define TNL_F_PMTUD (1 << 6) /* Enable path MTU discovery. */
+#define TNL_F_HDR_CACHE (1 << 7) /* Enable tunnel header caching. */
struct tnl_port_config {
__u32 flags;