- * @ip_summed: Consistently stores L4 checksumming status across different
- * kernel versions.
- * @csum_start: Stores the offset from which to start checksumming independent
- * of the transport header on all kernel versions.
- * packet was not received on a tunnel.
- * @vlan_tci: Provides a substitute for the skb->vlan_tci field on kernels
- * before 2.6.27.