gre_h
CTASSERT(sizeof(struct gre_h) == 4);
static int gre_input(struct gre_softc *, struct mbuf *, const struct gre_h *);
sc->sc_if.if_hdrlen = sizeof(struct ip) + sizeof(struct gre_h);
struct gre_h gh;
gre_input(struct gre_softc *sc, struct mbuf *m, const struct gre_h *gh)
hlen = sizeof(struct gre_h);
struct gre_h gh = { .flags = 0 };