NDD_ENABLE_ADDRESS Device Control Operation

The NDD_ENABLE_ADDRESS command enables the receipt of packets with an alternate (for example, multicast) address. The arg and length parameters specify the address and length in bytes of the alternate address to be enabled. The NDD_ALTADDRS flag in the ndd_flags field is set.

The device driver verifies that if the address is a valid multicast address. If the address is not a valid multicast address, the operation fails with an EINVAL error. If the address is valid, the driver adds it to its multicast table and enable the multicast filter on the adapter. The driver keeps a reference count for each individual address. Whenever a duplicate address is registered, the driver simply increments the reference count of that address in its multicast table, no update of the adapter's filter is needed. There is a hardware limitation on the number of multicast addresses in the filter.