Re: [PATCH net-next v4 15/15] mctp: Add MCTP overview document

[Eugene Syromiatnikov <esyr@redhat.com>]

On Thu, Jul 29, 2021 at 10:20:53AM +0800, Jeremy Kerr wrote:
> This change adds a brief document about the sockets API provided for
> sending and receiving MCTP messages from userspace.

[...]

> diff --git a/Documentation/networking/mctp.rst b/Documentation/networking/mctp.rst

[...]

> +``bind()`` : set local socket address
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +Sockets that receive incoming request packets will bind to a local address,
> +using the ``bind()`` syscall.
> +
> +.. code-block:: C
> +
> +    struct sockaddr_mctp addr;
> +
> +    addr.smctp_family = AF_MCTP;
> +    addr.smctp_network = MCTP_NET_ANY;
> +    addr.smctp_addr.s_addr = MCTP_ADDR_ANY;
> +    addr.smctp_type = MCTP_TYPE_PLDM;

[...]

> +``sendto()``, ``sendmsg()``, ``send()`` : transmit an MCTP message
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +An MCTP message is transmitted using one of the ``sendto()``, ``sendmsg()`` or
> +``send()`` syscalls. Using ``sendto()`` as the primary example:
> +
> +.. code-block:: C
> +
> +    struct sockaddr_mctp addr;
> +    char buf[14];
> +    ssize_t len;
> +
> +    /* set message destination */
> +    addr.smctp_family = AF_MCTP;
> +    addr.smctp_network = 0;
> +    addr.smctp_addr.s_addr = 8;
> +    addr.smctp_tag = MCTP_TAG_OWNER;
> +    addr.smctp_type = MCTP_TYPE_ECHO;

While MCTP_TYPE_PLDM and MCTP_TYPE_ECHO are mentioned
in the documentation, their definition is currently missing in the UAPI
header (or anywhere in the source tree at all).  Is that expected?