RL_RX_LIST_SZ
bzero(sc->rl_ldata.rl_rx_list, RL_RX_LIST_SZ(sc));
#define RL_RX_DMAMEM_SZ(sc) (RL_RX_LIST_SZ(sc) + RL_IP4CSUMTX_PADLEN)
#define RL_TXPADOFF(sc) RL_RX_LIST_SZ(sc)