set_tx_buff_desc_len_0
set_tx_buff_desc_len_0(tx_bd_desc, 0);
set_tx_buff_desc_len_0(tx_bd_desc, desc_size + 8);
set_tx_buff_desc_len_0(tx_bd_desc, desc_size);
set_tx_buff_desc_len_0(tx_bd_desc, desc_size);