eth_tx_next_bd
ASSERT_STATIC(OFFSETOF(struct eth_tx_next_bd, addr_hi) == OFFSETOF(lm_bd_chain_next, addr_hi)) ;
ASSERT_STATIC(OFFSETOF(struct eth_tx_next_bd, addr_lo) == OFFSETOF(lm_bd_chain_next, addr_lo)) ;
ASSERT_STATIC(OFFSETOF(struct eth_tx_next_bd, reserved)== OFFSETOF(lm_bd_chain_next, reserved) ) ;
struct eth_tx_next_bd next_bd /* Bd that contains the address of the next page */;