shim - transport/app communication

[Iljitsch van Beijnum <iljitsch@muada.com>]

Hi,

I was thinking: would it be useful for applications and/or transport to 
communicate with the shim using extension headers / options in select 
packets?

This has the nice property that it works regardless of how/where the 
shim is implemented, and it doesn't need any complex layer-to-layer 
communication mechanisms.

Shim-aware transports/applications could also emit periodic keepalives 
when they're otherwise idle so the shim knows it shouldn't remove state 
yet. (In fact many applications and/or TCP already do so.)