pflow_header
struct pflow_header *h;
h = mtod(m, struct pflow_header *);
(sizeof(struct pflow_header) + sizeof(struct pflow_flow))
sc->sc_maxcount = (mtu - sizeof(struct pflow_header) -
sc->sc_if.if_mtu = sizeof(struct pflow_header) +
struct pflow_header h;
#define PFLOW_HDRLEN sizeof(struct pflow_header)