PROTO_HDR_SHIFT
#define PROTO_HDR_FIELD_START(proto_hdr_type) ((proto_hdr_type) << PROTO_HDR_SHIFT)
#define PROTO_HDR_FIELD_MASK ((1UL << PROTO_HDR_SHIFT) - 1)
(((hdr)->type) >> PROTO_HDR_SHIFT)
((hdr)->type == ((s32)((val) >> PROTO_HDR_SHIFT)))