Function stf_clone_create

freebsd/net/if_stf.c:196–265

}

static int
stf_clone_create(struct if_clone *ifc, char *name, size_t len, caddr_t params)
{
	char *dp;
	int err, unit, wildcard;
	struct stf_softc *sc;
	struct ifnet *ifp;

	err = ifc_name2unit(name, &unit);
	if (err != 0)
		return (err);
	wildcard = (unit < 0);

	/*
	 * We can only have one unit, but since unit allocation is
	 * already locked, we use it to keep from allocating extra
	 * interfaces.
	 */
	unit = STFUNIT;
	err = ifc_alloc_unit(ifc, &unit);
	if (err != 0)
		return (err);

	sc = malloc(sizeof(struct stf_softc), M_STF, M_WAITOK | M_ZERO);
	ifp = STF2IFP(sc) = if_alloc(IFT_STF);
	if (ifp == NULL) {
		free(sc, M_STF);
		ifc_free_unit(ifc, unit);
		return (ENOSPC);
	}
	ifp->if_softc = sc;
	sc->sc_fibnum = curthread->td_proc->p_fibnum;

	/*
	 * Set the name manually rather then using if_initname because
	 * we don't conform to the default naming convention for interfaces.
	 * In the wildcard case, we need to update the name.
	 */
	if (wildcard) {
		for (dp = name; *dp != '\0'; dp++);
		if (snprintf(dp, len - (dp-name), "%d", unit) >
		    len - (dp-name) - 1) {
			/*
			 * This can only be a programmer error and
			 * there's no straightforward way to recover if
			 * it happens.
			 */
			panic("if_clone_create(): interface name too long");
		}
	}
	strlcpy(ifp->if_xname, name, IFNAMSIZ);
	ifp->if_dname = stfname;
	ifp->if_dunit = IF_DUNIT_NONE;

	sc->encap_cookie = ip_encap_attach(&ipv4_encap_cfg, sc, M_WAITOK);
	if (sc->encap_cookie == NULL) {
		if_printf(ifp, "attach failed\n");
		free(sc, M_STF);