POC: Extending Kernel notifier framework to send messages to user space

[maryamtahhan]

Presently, all Kernel Hardware Offload L2 and L3 notifications have no user space visibility and no means of accessing/controlling them via netlink. They are intended to be used by device drivers. An offload capable device driver registers a listener, receives these notifications, processes the information and informs the kernel if it performs any offloads. At that point, the kernel will mark any offloaded L2 and L3 forwarding entries. Expiration timers and stats for them will no longer be available.

The goal of this task is to enable a user space notification mechanism for when these events happen so that the Kernel sends notifications to a user space application which can also respond to these notifications

DOD: patches pushed to a github repo

[maryamtahhan]

Current POC and patches are available at: https://github.com/kot-begemot-uk/bpfnic-ng

The POC captures kernel switchdev L2 notifications, sends them to userspace, simulates userspace processing, sends a modified notification back to the kernel and issues a response.

[maryamtahhan]

TODO - work with Anton to get him added to the project as a contributor when he's back from PTO...