MAC_LEN
if (macaddr == NULL || prop_len != MAC_LEN)
newmac = kzalloc(sizeof(*newmac) + MAC_LEN, GFP_KERNEL);
newmac->length = MAC_LEN;
memcpy(newmac->value, macaddr, MAC_LEN);
unsigned char mac[MAC_LEN],inv_mac[MAC_LEN];