KTLS with zfs recv

[Rodney W. Grimes]

> On Fri, Feb 26, 2021 at 9:24 AM Rodney W. Grimes <
> freebsd-rwg at gndrsh.dnsmgr.net> wrote:
> 
> > > My understanding is that KTLS works very well with OpenSSL for sending,
> > but
> > > not as well for receiving, because there's nothing like a recvfile
> > > syscall.  However, it works great for both send and receive with NFS,
> > where
> > > all the data remains in the kernel. What about zfs recv?  A very common
> > > pattern is for an application to read from an SSL socket and then pipe
> > the
> > > data to zfs recv. For example, zrepl does that.  Could zfs recv instead
> > > read directly from the KTLS socket, bypassing userspace?  That could
> > > potentially save a _lot_ of cycles for a _lot_ of people.
> >
> > I did some patches and a short presentation at BSDCan that basically
> > shoves the whole zfs send and zfs recv process into the kernel, ie
> > it opens the sockets up, makes the connections, then the socket
> > is passed into the kernel(s) and it all runs in kernel mode.
> >
> >
> > https://www.bsdcan.org/2018/schedule/attachments/479_BSDCan-2018-zfs-send.pdf
> >
> > A few things need fixed like reversing who does the listen for
> > security reasons, but this feature is probably ready for prime
> > time.
> >
> > > -Alan
> >
> > --
> > Rod Grimes
> > rgrimes at freebsd.org
> 
> 
> That looks potentially useful, but it doesn't use encryption.  Would it
> work if the socket had been opened by openssl with ktls?

Yes, it should.  Internally the zfs send and recv code just does reads
and writes to the socket, so what ever you setup for "connected" sockets
should work.

-- 
Rod Grimes                                                 rgrimes at freebsd.org