This patch adds very basic support for getting information about RDMA
networking device; starting with device index, name, firmware version,
node GUID and system image GUID.
This is done through RDMA netlink socket.
RDMA devices are some what similar to Ethernet devices.
However there are few major differences between them.
RDMA devices usually have one or two ports, unlike Ethernet devices.
Each port has its own attributes, state and network addresses which are
different than Ethernet devices (Link and LinkAttrs). They almost don't
overlap with Link and LinkAttrs.
Therefore it doesn't derive Link and LinkAttrs structure; instead they
are represented using RdmaLink and RdmaLinkAttrs.
RdmaLink represents a RDMA device containing its attributes.
All Rdma device communication occurs through rdma subsystem's netlink
socket.
Signed-off-by: Parav Pandit parav@mellanox.com