RE: io_uring: BPF controlled I/O

[David Laight]

From: Victor Stewart
> Sent: 07 June 2021 19:51
...
> coincidentally i'm tossing around in my mind at the moment an idea for
> offloading
> the PING/PONG of a QUIC server/client into the kernel via eBPF.
> 
> problem being, being that QUIC is userspace run transport and that NAT-ed UDP
> mappings can't be expected to stay open longer than 30 seconds, QUIC
> applications
> bare a large cost of context switching wake-up to conduct connection lifetime
> maintenance... especially when managing a large number of mostly idle long lived
> connections. so offloading this maintenance service into the kernel
> would be a great
> efficiency boon.
> 
> the main impediment is that access to the kernel crypto libraries
> isn't currently possible
> from eBPF. that said, connection wide crypto offload into the NIC is a
> frequently mentioned
> subject in QUIC circles, so one could argue better to allocate the
> time to NIC crypto offload
> and then simply conduct this PING/PONG offload in plain text.

Hmmmm... a good example of how not to type emails.

Thought, does the UDP tx needed to keep the NAT tables active
need to be encrypted?
A single byte UDP packet would do the trick.
You just need something the remote system is designed to ignore.

	David

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