mctp: Userspace tools for MCTP stack management

This project contains two utilities for running a MCTP network from the local machine:

• mctp: A small command-line utility to query and manage the state of the kernel MCTP stack, in a similar way to iproute2's ip utility.

• mctpd: A daemon implementing the MCTP control protocol; you'll need this for the local host to perform as a bus-owner. The main function of mctpd is to assign EIDs to remote endpoints, and manage the resulting routes and neighbour-table entries for those endpoints.

Building & installing

This project uses meson for building. To configure and compile:

$ meson setup obj
$ ninja -C obj

to install to the default prefix (/usr/local), with optional DESTDIR:

$ meson install -C obj

For integration with systemd, there are a few example configuration files and systemd target definitions under the conf/ directory. These are not installed by default.

By default, meson is configured to enable tests, which requires a few extra dependencies (mainly pytest, python libraries, and dbus-run-session). In cases where the tests are not required, you can avoid these dependencies by configuring the build tree with -Dtests=false:

$ meson setup obj -Dtests=false

mctp Usage

Use mctp help for the list of available commands:

$ mctp help
mctp link
mctp link show [ifname]
mctp link set <ifname> [up|down] [mtu <mtu>] [network <net>] [bus-owner <physaddr>]

mctp address
mctp address show [IFNAME]
mctp address add <eid> dev <IFNAME>
mctp address del <eid> dev <IFNAME>

mctp route
mctp route show [net <network>]
mctp route add <eid> via <dev> [mtu <mtu>]
mctp route del <eid> via <dev>

mctp neigh
mctp neigh show [dev <network>]
mctp neigh add <eid> dev <device> lladdr <physaddr>
mctp neigh del <eid> dev <device>

mctpd Usage

mctpd should be run as a system service, once the local MCTP stack has been configured (ie., interfaces are enabled, and local addresses have been assigned). There are two sample systemd unit files under the conf/ directory, to coordinate the local setup and the supervision of the mctpd process.

The mctpd daemon will expose a dbus interface, claiming the bus name xyz.openbmc_project.MCTP and object path /xyz/openbmc_project/mctp. This provides a few functions for configuring remote endpoints:

# busctl introspect xyz.openbmc_project.MCTP /xyz/openbmc_project/mctp
NAME                                TYPE      SIGNATURE  RESULT/VALUE  FLAGS
au.com.CodeConstruct.MCTP           interface -          -             -
.AssignEndpoint                     method    say        yisb          -
.AssignEndpointStatic               method    sayy       yisb          -
.LearnEndpoint                      method    say        yisb          -
.SetupEndpoint                      method    say        yisb          -

Results of mctpd enumeration are also represented as dbus objects, using the OpenBMC-specified MCTP endpoint format. Each endpoint appears on the bus at the object path:

/xyz/openbmc_project/mctp/<network-id>/<endpoint-id>

where mctpd exposes three dbus interfaces for each:

• xyz.openbmc_project.MCTP.Endpoint: Provides MCTP address information (EID and NetworkID properties) and message-type support SupportedMessageTypes property).

  This interface is defined by the MCTP.Endpoint phosphor-dbus specification.

• xyz.openbmc_project.Common.UUID: MCTP UUID of the discovered endpoint (UUID property).

  This interface is defined by the Common.UUID phosphor-dbus specification.

• au.com.CodeConstruct.MCTP.EndPoint: Additional control methods for the endpoint - for example, Remove

Testing

We have an initial test suite under tests/. To run:

meson setup obj
ninja -C obj test

Alternatively, you can run pytest directly; this may be more useful during development:

cd obj
pytest

The test infrastructure depends on a few python packages, including the pytest binary. You can use a python venv to provide these:

python3 -m venv venv
venv/bin/pip install -r tests/requirements.txt

Then run the tests using the new venv's pytest:

PATH=$PWD/venv/bin/:$PATH meson setup obj
ninja -C obj test