Date: Mon, 01 Jul 2002 08:49:14 -0600 From: Arthur Peet <arthur.peet@toltec.biz> To: Julian Elischer <julian@elischer.org> Cc: freebsd-net@FreeBSD.ORG Subject: Re: bpf/netgraph interaction Message-ID: <5.1.1.6.2.20020628085502.00a6bf08@mail.toltecint.net> In-Reply-To: <Pine.BSF.4.21.0206271614240.69706-100000@InterJet.elischer .org> References: <5.1.1.6.2.20020627170548.0220fb38@mail.toltecint.net>
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Julian,
Thanks for your assistance. My understanding of the use and power of
netgraph is
much improved. Your first response to my question (Go to the source, ...),
gave me the
idea to filter the response "from" the process which was using BPF for it's
read and write
operations. This was done in hope the BPF injection also occurred before
netgraph hook
for the transactions to the interface (again, I was not able to prove this
in the source).
This gave me the result I was looking for.
Thanks again,
Art
At 05:20 PM 6/27/2002, Julian Elischer wrote:
>Ipfw divers from within the IP stack
>by then it's too late.
>
>you could diver th epackets using netgraph and filter them and then
>pass them back into the eiface netgraph node to continue up.
>
>then you tell your application to listen to the "nge"
>interface.. unfortunatly another driver also produces 'nge' interfaces,
>but the chance you have htat card is quite small.
>
>
>
>[fxp0]<--->[ng_ether]<----->{filter}<--->ng_eiface<---->[IP stack]
> \
> \---BPF
>
>
>
>
>
>
>
>On Thu, 27 Jun 2002, Arthur Peet wrote:
>
> > At 04:50 PM 6/27/2002, Julian Elischer wrote:
> > > > Are there any other taps I may access in order to accomplish this goal?
> > >
> > >I forget the goal. sorry
> >
> >
> >
> > No problem - Hope you don't mind if I restate it.
> > I am trying to strip/drop packets before they reach a server process
> which uses
> > BPF for communicating with the network interface.
> > I have briefly been looking into using an ipfw/divert socket, but I don't
> > think that is
> > going to work either.
> >
> > Thanks again!
> > -Art
> >
> >
> >
> >
> >
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
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> >
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