Re: Julian's netowrking challenge 2005

From: Milan Obuch (net_at_dino.sk)
Date: 06/28/05

  • Next message: Max Laier: "Re: Julian's netowrking challenge 2005" 
    To: freebsd-net@freebsd.org
Date: Tue, 28 Jun 2005 13:10:10 +0200

    On Tuesday 28 June 2005 12:37, Max Laier wrote:
    > On Tuesday 28 June 2005 12:27, Jeremie Le Hen wrote:
    > > > Wouldn't a more general approach be better. e.g. a way to "tag" a
    > > > packet before it is sent to divert and a matching tag-lookup that can
    > > > do further action. This would make it very easy to do all kinds of
    > > > stuff that needs to know the original address instead of the translated
    > > > one while avoiding code duplication.
    > >
    > > Having the possibility to tag a packet would be worth indeed. But I
    > > think that Milan wants to bring network stack virtualization in
    > > newer release of FreeBSD IIUC. This would be, IMO, a great improvement
    > > of FreeBSD networking, although I'm pretty sure this would make Netgraph
    > > people react a bit ;-).
    >
    > Stack virtualization is independent of this. All I am trying to say here,
    > is that I think it is better to have a general mechanism to do thing like
    > that, instead of a special solution for fwd (i.e. set-nexthop).
    >

    We agree on this. Tagging and virtualization are independent and solve
    different purposes. My reaction was to post mentioning request caused from
    various limitations/deficiences, namely lack of multiple routing tables
    support.

    > > > pf does something along these lines in case you are looking for
    > > > references.
    > >
    > > Would it be possible to share this tag among pf and ipfw ?
    >
    > Sure, it's a simple mbuf tag with a (at this point) 16bit cookie. The
    > downside of this approach is that you need to malloc the tag, but on the
    > other hand it's even more complicated for set-nexthop where you need to
    > allocate a route and maybe even hold it for some time and make sure you
    > properly GC it ... tags seem way simpler to me.

    Agreed. I am far from being networking code guru, so maybe this question
    sounds stupid, but could not this cookie be allocated when packet enters
    system? Maybe optionally...

    Milan
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  • Next message: Max Laier: "Re: Julian's netowrking challenge 2005"

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