struct ofpbuf *ofpbuf_clone_with_headroom(const struct ofpbuf *,
size_t headroom);
struct ofpbuf *ofpbuf_clone_data(const void *, size_t);
struct ofpbuf *ofpbuf_clone_with_headroom(const struct ofpbuf *,
size_t headroom);
struct ofpbuf *ofpbuf_clone_data(const void *, size_t);