ethernetif_init() function
Should be called at the beginning of the program to set up the network interface. It calls the function low_level_init() to do the actual setup of the hardware. This function should be passed as a parameter to netif_add().
Arguments
netif
the lwip network interface structure for this ethernetif
Return value
ERR_OK if the loopif is initialized ERR_MEM if private data couldn't be allocated any other err_t on error