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gerrit.openbmc.org / openbmc / libmctp / 195a7c5e212f7fb50c850880519073ec99133607
commit195a7c5e212f7fb50c850880519073ec99133607[log] [tgz]
authorJeremy Kerr <jk@ozlabs.org>Mon Jun 24 14:24:56 2019 +0800
committerJeremy Kerr <jk@ozlabs.org>Tue Jun 25 03:35:42 2019 +0000
tree59fd93a28a255c6d68a4fe332531059e8d6eabf3
parent1a4b55ac35828873b6e59e841ba8f659a58ae17d [diff]
demux-daemon: Add support for loopback messages

If a demux client sends a message addressed to the local EID, loop it
back to other clients.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Change-Id: I6ae4720688d6ad3e50793f1d74aa50259797649e
1 file changed
tree: 59fd93a28a255c6d68a4fe332531059e8d6eabf3
  1. tests/
  2. utils/
  3. alloc.c
  4. astlpc.c
  5. bootstrap.sh
  6. CMakeLists.txt
  7. configure.ac
  8. core.c
  9. libmctp-alloc.h
  10. libmctp-astlpc.h
  11. libmctp-log.h
  12. libmctp-serial.h
  13. libmctp.h
  14. LICENSE
  15. log.c
  16. Makefile.am
  17. Makefile.inc
  18. README.md
  19. serial.c
README.md

libmctp: Implementation of MCTP (DTMF DSP0236)

This library is intended to be a portable implementation of the Management Component Transport Protocol (MCTP), as defined by DMTF standard "DSP0236", plus transport binding specifications.

Currently, the library is is only at prototyping stage. Interfaces will likely change, and are missing lots of components of the standard.

Core API

To initialise the MCTP stack with a single hardware bus:

  • mctp = mctp_init(): Initialise the MCTP core
  • binding = mctp_<binding>_init(): Initialise a hardware binding
  • mctp_register_bus(mctp, binding, eid): Register the hardware binding with the core, using a predefined EID

Then, register a function call to be invoked when a message is received:

  • mctp_set_rx_all(mctp, function): Provide a callback to be invoked when a MCTP message is received

Or transmit a message:

  • mctp_message_tx(mctp, message, len): Transmit a MCTP message

The binding may require you to notify it to receive packets. For example, for the serial binding, the mctp_serial_read() function should be invoked when the file-descriptor for the serial device has data available.

Integration

The libmctp code is intended to be integrated into other codebases by two methods:

  1. as a simple library (libmctp.{a,so}) which can be compiled separately and linked into the containing project

  2. as a set of sources to be included into the containing project (either imported, or as a git subtree/submodule)

For (1), you can use the top-level makefile to produce libmtcp.a.

For (2), the Makefile.inc file provides the minimum set of dependencies to either build libmctp.a, or just the actual object files (LIBMCTP_OBS), which you can include into your existing make definitions. You'll want to set LIBMTCP_DIR to refer to the subdirectory that contains that makefile, so we can set the correct paths to sources.

Environment configuration

This library is intended to be portable to be used in a range of environments, but the main targets are:

  • Linux userspace, typically for BMC use-cases
  • Low-level firmware environments

For the latter, we need to support customisation of the functions that libmctp uses (for example, POSIX file IO is not available).

In order to support these, we have a few compile-time definitions:

  • MCTP_HAVE_FILEIO: define if POSIX file io is available, allowing the serial hardware binding to access char devices for IO.

  • MCTP_HAVE_SYSLOG: allow logging to syslog, through the vsyslog call.

  • MCTP_DEFAULT_ALLOC: set default allocator functions (malloc, free, realloc), so that applications do not have to provide their own.

TODO

  • Partial packet queue transmit
  • Control messages
  • Message- and packet-buffer pools and preallocation
  • C++ API
  • Non-file-based serial binding