MACB_TX_LEN_ALIGN
if (!IS_ALIGNED(skb_headlen(skb) - hdrlen, MACB_TX_LEN_ALIGN))
if (!IS_ALIGNED(skb_frag_size(frag), MACB_TX_LEN_ALIGN))
#define MACB_MAX_TX_LEN ((unsigned int)((1 << MACB_TX_FRMLEN_SIZE) - 1) & ~((unsigned int)(MACB_TX_LEN_ALIGN - 1)))