My planned work on networking stack

Andre Oppermann andre at freebsd.org
Tue Mar 2 13:19:22 PST 2004


Bruce M Simpson wrote:
> 
> On Tue, Mar 02, 2004 at 07:09:02PM +0300, Gleb Smirnoff wrote:
> >   I do not insist that AS pathes in kernel are good idea. If you show me an
> > other way to get AS information when constructing netflow exports in kernel,
> > I'd be thankful. I'd be also thankful if you describe how policy routing can be
> > implemented while no AS info in kernel.
> >   What do other FreeBSD networking withards think?
> 
> I don't see any reason why we couldn't accept, for example, a 32-bit cookie
> for abuse by a userland daemon, with pid, as it pleases (via an rtmsg
> extension and PF_ROUTE). That is generic enough to provide the tie-in
> needed with the userland RIB and the kernel FIB.

Ugh, I'm happily running my accounting in userland via BPF/PCAP and it
adds only 2-3% CPU load.  The BGP information I get from MRT routing
table dumps.  Pretty slick stuff.  We (Claudio and me) are preparing it
for public release later this week.

>From my experience here and a performance point of view there is no need
to do netflow and related accounting stuff in the kernel at all.  Userland
is much more flexible.

> ABI breakage may occur, but I would consider that the PF_ROUTE code is in need
> of an overhaul anyway (see my mail to ru@ from some months ago on -current or
> -net with code able to panic a kernel through malformed rtmsg contents).

Please don't break the current RTM5 API.  We will design a nice and much
more flexible RTM6 message format later this year.  It needs a good deal
of deep thought and not be rushed just for the sake of it.

-- 
Andre


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