gre_hdr
free(sc->gre_hdr, M_GRE);
bcopy(sc->gre_hdr, mtod(m, void *), sc->gre_hlen);
free(sc->gre_hdr, M_GRE);
free(sc->gre_hdr, M_GRE);
sc->gre_hdr = ip;
free(sc->gre_hdr, M_GRE);
free(sc->gre_hdr, M_GRE);
free(sc->gre_hdr, M_GRE);
sc->gre_hdr = ip6;
free(sc->gre_hdr, M_GRE);