bpftune-netns8

bpftune needs to be namespace-aware; when it receives events, they are tied to a specific netns cookie, and if we see an event in that netns we want to be able to auto-tune within it and not in the global network namespace.

On startup, the netns tuner iterates over the various sources of netns info to collate a list of network namespaces, and supplements this by watching for addition of network namespaces via BPF. Using this info, we can then maintain tuner state on a per-namespace basis.

Per-namespace support requires netns cookie support; running "bpftune -S" shows if this is present.