TI-RPC introduces the capability of performing RPC over AF_LOCAL
sockets. It uses this mainly for registering and unregistering
local RPC services securely with the local rpcbind, but we could
also conceivably use it as a generic upcall mechanism.
This patch provides a client-side only implementation for the moment.
We might also consider a server-side implementation to provide
AF_LOCAL access to NLM (for statd downcalls, and such like).
Autobinding is not supported on kernel AF_LOCAL transports at this
time. Kernel ULPs must specify the pathname of the remote endpoint
when an AF_LOCAL transport is created. rpcbind supports registering
services available via AF_LOCAL, so the kernel could handle it with
some adjustment to ->rpcbind and ->set_port. But we don't need this
feature for doing upcalls via well-known named sockets.
This has not been tested with ULPs that move a substantial amount of
data. Thus, I can't attest to how robust the write_space and
congestion management logic is.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>