On Tue, 8 Jun 2021 17:03:16 -0400
Alexander Aring [off-list ref] wrote:

Hi,

On Tue, Jun 8, 2021 at 3:36 AM Stefan Metzmacher [off-list ref] wrote:
...

quoted

quoted

2) then switch focus to porting a smaller C userspace implementation of
QUIC to Linux (probably not msquic since it is larger and doesn't
follow kernel style)
to kernel in fs/cifs  (since currently SMB3.1.1 is the only protocol
that uses QUIC,
and the Windows server target is quite stable and can be used to test against)> 3) use the userspace upcall example from step 1 for
comparison/testing/debugging etc.
since we know the userspace version is stable  

With having the fuse-like socket before it should be trivial to switch
between the implementations.  

So a good starting point would be to have such a "fuse-like socket"
component? What about having a simple example for that at first
without having quic involved. The kernel calls some POSIX-like socket
interface which triggers a communication to a user space application.
This user space application will then map everything to a user space
generated socket. This would be a map from socket struct
"proto/proto_ops" to user space and vice versa. The kernel application
probably can use the kernel_FOO() (e.g. kernel_recvmsg()) socket api
directly then. Exactly like "fuse" as you mentioned just for sockets.

I think two veth interfaces can help to test something like that,
either with a "fuse-like socket" on the other end or an user space
application. Just doing a ping-pong example.

Afterwards we can look at how to replace the user generated socket
application with any $LIBQUIC e.g. msquic implementation as second
step.

- Alex

Socket state management is complex and timers etc in userspace are hard.