bridge: mcast: Allow user space to add (*, G) with a source list and filter mode

bridge: mcast: Allow user space to add (*, G) with a source list and filter mode

Add new netlink attributes to the RTM_NEWMDB request that allow user
space to add (*, G) with a source list and filter mode.

The RTM_NEWMDB message can already dump such entries (created by the
kernel) so there is no need to add dump support. However, the message
contains a different set of attributes depending if it is a request or a
response. The naming and structure of the new attributes try to follow
the existing ones used in the response.

Request:

[ struct nlmsghdr ]
[ struct br_port_msg ]
[ MDBA_SET_ENTRY ]
	struct br_mdb_entry
[ MDBA_SET_ENTRY_ATTRS ]
	[ MDBE_ATTR_SOURCE ]
		struct in_addr / struct in6_addr
	[ MDBE_ATTR_SRC_LIST ]		// new
		[ MDBE_SRC_LIST_ENTRY ]
			[ MDBE_SRCATTR_ADDRESS ]
				struct in_addr / struct in6_addr
		[ ...]
	[ MDBE_ATTR_GROUP_MODE ]	// new
		u8

Response:

[ struct nlmsghdr ]
[ struct br_port_msg ]
[ MDBA_MDB ]
	[ MDBA_MDB_ENTRY ]
		[ MDBA_MDB_ENTRY_INFO ]
			struct br_mdb_entry
		[ MDBA_MDB_EATTR_TIMER ]
			u32
		[ MDBA_MDB_EATTR_SOURCE ]
			struct in_addr / struct in6_addr
		[ MDBA_MDB_EATTR_RTPROT ]
			u8
		[ MDBA_MDB_EATTR_SRC_LIST ]
			[ MDBA_MDB_SRCLIST_ENTRY ]
				[ MDBA_MDB_SRCATTR_ADDRESS ]
					struct in_addr / struct in6_addr
				[ MDBA_MDB_SRCATTR_TIMER ]
					u8
			[...]
		[ MDBA_MDB_EATTR_GROUP_MODE ]
			u8

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>