There is diagnostic value in being able to disambiguate between the
various reasons why an IB CM has rejected a connection attempt.  In
particular, reason 8 "invalid service ID" can be used to identify an
incorrect SRP service_id root-path component, and reason 28 "consumer
reject" corresponds to a genuine SRP login rejection IU, which can be
passed up to the SRP layer.

For rejection reasons other than "consumer reject", we should not pass
through the private data, since it is most likely generated by the CM
without any protocol-specific knowledge.

A management interface is the component through which both local and
remote management agents are accessed.

This new implementation of a management interface allows for the user
to react to timed-out transactions, and also allows for cancellation
of in-progress transactions.

The Communication Manager is responsible for handling the setup and
teardown of RC connections.

The GMA code was based upon the SMA code.  We can save space by making
the SMA simply an instance of the GMA.

Generalise out the multicast group membership record code from IPoIB.

Generalise the subnet management agent into a general management agent
capable of sending and responding to MADs, including support for
retransmissions as necessary.

Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

The return path in directed route SMPs lists the egress ports in order
from SM to node, rather than from node to SM.

To write to the correct offset within the return path, we need to
parse the hop pointer.  This is held within the class-specific data
portion of the MAD header, which was previously unused by us and
defined to be a uint16_t.  Define this field to be a union type; this
requires some rearrangement of ib_mad.h and corresponding changes to
ipoib.c.

Not all Infiniband cards have embedded subnet management agents.
Split out the code that communicates with such an embedded SMA into a
separate ib_smc.c file, and have drivers call ib_smc_update()
explicitly when they suspect that the answers given by the embedded
SMA may have changed.