Date: Sat, 29 Jun 2013 13:56:22 -0700 From: Peter Wemm <peter@wemm.org> To: Hiroki Sato <hrs@freebsd.org> Cc: freebsd-net@freebsd.org Subject: Re: Looking for a bgp listener that works with RADIX_MPATH / EQMP that's in HEAD Message-ID: <CAGE5yCq3HiE20J9-S1-gL_GRHfnV%2BQnxhMULYiJ%2B4E=T7fQywQ@mail.gmail.com> In-Reply-To: <20130630.054258.1958564335251044000.hrs@allbsd.org> References: <CAGE5yCpTjKOeZDCKGU6QC_FVmNrbPnp4BiZP0fYi5oYxk1DgUw@mail.gmail.com> <20130630.054258.1958564335251044000.hrs@allbsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, Jun 29, 2013 at 1:42 PM, Hiroki Sato <hrs@freebsd.org> wrote: > Peter Wemm <peter@wemm.org> wrote > in <CAGE5yCpTjKOeZDCKGU6QC_FVmNrbPnp4BiZP0fYi5oYxk1DgUw@mail.gmail.com>: > > pe> I'm looking for pointers to something that can listen to bgp default > pe> route announcements from two outbound gateways and set a RADIX_MPATH > pe> compatible default route based on whether one or both are alive. > pe> > pe> openbgpd from ports is extremely incompatible with RADIX_MPATH on 10. > pe> You *have* to turn off fib (kernel routing table) updates or it will > pe> destroy your machine when it runs out of physical memory for duplicate > pe> routes. > pe> > pe> I know I can do an evil hack and poll the 'bgp show ...' output and > pe> manually update the default route but that means updates are delayed > pe> to the poll interval. I'm hoping there is a more elegant solution > pe> that already works and is immediately responsive to a change in bgp > pe> state. > pe> > pe> The caveat is it *must* run on 10.x, with RADIX_MPATH enabled. I'd > pe> gladly run openbgpd if it actually worked. openbgpd has some > pe> awareness of mpath so it might be fixable but openbsd's multipath is > pe> different to ours. > pe> > pe> Ideas? > > Unfortunately openbgpd does not work well with RADIX_MPATH yet. As > you pointed out, it is due to difference of multiple routes support > between FreeBSD and OpenBSD. I think FIB handling can be improved, > but needs some more investigation for that. Yes, the port is extremely dangerous if RADIX_MPATH is enabled. It does this sort of thing: cmd = RTM_ADD retry: error = routectl(cmdl, data); if (error && cmd == RTM_ADD) { cmd = RTM_CHANGE; goto retry; } In short, it creates duplicates every single time there's a fib change if you enable RADIX_MPATH. This does not end well. It appears that openbsd allows multiple overlapping routes to coexist if they have a MPATH flag on them. Our radix structure is quite different from what I understand, but the routing socket interface causes openbgpd to accidently work and spam the rables. > I think Quagga and BIRD can work with injecting ECMP routes into > RADIX_MPATH-enabled FIB. > > -- Hiroki I'm looking for some examples. See the bgpd.conf fragments I sent Scott. -- Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com; KI6FJV On IRC, talking about C++: <BigKnife> I think that it is a good thing I will never meet Bjarne on a street <BigKnife> cause really, I don't want to end up in prison or anything
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAGE5yCq3HiE20J9-S1-gL_GRHfnV%2BQnxhMULYiJ%2B4E=T7fQywQ>