NVIDIA/mctp

NVIDIA/mctp

Description: Userspace tools for MCTP stack management

Language: C

License: GPL-2.0

Stars: 5

Forks: 1

Open issues: 0

Created: 2025-11-04T17:41:45Z

Pushed: 2026-06-10T18:07:55Z

Default branch: develop

Fork: no

Archived: no

README: 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 [up|down] [mtu ] [network ] [bus-owner ]

mctp address mctp address show [IFNAME] mctp address add dev mctp address del dev

mctp route mctp route show [net ] mctp route add [-] via [mtu ] mctp route add [-] gw [net ] [mtu ] mctp route del [-] via mctp route del [-] gw [net ]

mctp neigh mctp neigh show [dev ] mctp neigh add dev lladdr mctp neigh del dev

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.

mctpd can read some basic configuration from a file, by default /etc/mctpd.conf, but other files can be specified with the -c FILE argument. An example configuration is in [conf/mctpd.conf](conf/mctpd.conf).

The mctpd daemon will expose a dbus interface, claiming the bus name au.com.codeconstruct.MCTP1 and object path /au/com/codeconstruct/mctp1.

Each detected MCTP interface on the system provides a few functions for configuring remote endpoints on that bus:

busctl introspect au.com.codeconstruct.MCTP1 /au/com/codeconstruct/mctp1/interfaces/mctpi2c1

NAME TYPE SIGNATURE RESULT/VALUE FLAGS au.com.codeconstruct.MCTP.Interface1 interface - - - .AssignEndpoint method ay yisb - .AssignEndpointStatic method ayyay yisb - .LearnEndpoint method ay yisb - .SetupEndpoint method ay 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:

/au/com/codeconstruct/mctp/networks//endpoints/

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.MCTP1.Endpoint1: 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 ../tests

To run without an existing dbus session:

dbus-run-session env DBUS_STARTER_BUS_TYPE=user pytest ../tests

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