Title: setup_read() / mnx_eth

setup_read(eth_port) sends a message to the ethernet task inquiring whether an ethernet packet has arrived that is destined for the ethernet port eth_port, setup_read()'s only parameter. If a datagram has arrived, the datagram is copied to a buffer within the network service and the datagram is handed off to eth_arrive().

After processing all the packets that the ethernet task has received and copied over to the network service, setup_read() leaves a buffer in the ethernet port's etp_rd_pack field to which the ethernet task can later copy another ethernet packet after the packet arrives.