forked from Imagelibrary/rtems
243ddb52b3
It enabled promiscous mode or sets the multicast filter according to the configuration and parameters to ioctl(SIOCSIFFLAGS), ioctl(SIOCADDMULTI) and ioctl(SIOCDELMULTI). On SIOCADDMULTI/SIOCDELMULTI requests the greth ioctl calls the Ethernet helper functions ether_addmulti()/ether_delmulti() which tells the greth driver when its required to update the MAC multicast filtering. The interface notifies support for multicast by setting IFF_MULTICAST. The GRETH has two registers which contains a bit-mask of allowed MAC addresses. The incomming MAC address is CRC:ed and the CRC is used as an index into the bit-mask to determine to allow or drop the frame.