Re: New Syscall

[David Laight <david%l8s.co.uk@localhost>]

On Thu, Oct 15, 2015 at 02:12:35PM +0100, Robert Swindells wrote:
> 
> Taylor R Campbell wrote:
> >   Date: Wed, 14 Oct 2015 22:55:41 +0100 (BST)
> >   From: Robert Swindells <rjs%fdy2.co.uk@localhost>
> >
> >   The syscall is sctp_peeloff().
> >
> >Hmm...  Introducing a protocol-specific syscall doesn't strike me as a
> >great design.  I can imagine wanting to do something similar with,
> >e.g., minimalt, if we ever had that in-kernel.
> >
> >If we have to have something protocol-specific, an ioctl would work
> >just as well, and use up a somewhat less scarce resource.
> 
> The code is from KAME, I didn't write it from scratch, FreeBSD also has
> a syscall for it.
> 
> Linux uses getsockopt() for this, which seems wrong to me as you are
> not just reading a setting when you make the call.

Be careful, I think one of the sctp rfs requires the use of
setsockopt() for a lot of things that ought to be separate
socket calls.
I can't remember about peeloff.

The 'peeloff' code really shouldn't have been anything to do
with sctp - it is just is method of multiplexing connections
over a single socket.
A strange solution to the problem I think they were trying to solve.

Not that much of sctp works the way people expect it to...

	David

-- 
David Laight: david%l8s.co.uk@localhost