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Mat Martineau says: ==================== mptcp: Add SOL_MPTCP getsockopt support Here's the first new MPTCP feature for the v5.16 cycle, and I'll defer to Florian's helpful description of the series implementing some new MPTCP socket options: ======== This adds the MPTCP_INFO, MPTCP_TCPINFO and MPTCP_SUBFLOW_ADDRS mptcp getsockopt optnames. MPTCP_INFO exposes the mptcp_info struct as an alternative to the existing netlink diag interface. MPTCP_TCPINFO exposes the tcp_info struct. Unlike SOL_TCP/TCP_INFO, this returns one struct for each active subflow. MPTCP_SUBFLOW_ADDRS allows userspace to discover the ip addresses/ports used by the local and remote endpoints, one for each active tcp subflow. MPTCP_TCPINFO and MPTCP_SUBFLOW_ADDRS share the same meta-header that needs to be pre-filled by userspace with the size of the data structures it expects. This is done to allow extension of the involved structs later on, without breaking backwards compatibility. The meta-structure can also be used to discover the required space to obtain all information, as kernel will fill in the number of active subflows even if there is not enough room for the requested info itself. More information is available in the individual patches. Last patch adds test cases for the three optnames. ======== ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.