[Click] Patchless kernel click problem

[Joonwoo Park]

Hi Roman,

Have you had a chance to test with 2.6.37 with the patches here
https://github.com/kohler/click/pull/12 ?
The patch uses another way to steal packet from linux as linux 2.6.37
doesn't expose bridge packet hooking point.
I haven't seriously looked how it impacts to this behaviour but it's
possible 2.6.37 with that patch is different.

Joonwoo

On Wed, May 11, 2011 at 4:45 PM, Roman Chertov <rchertov at cs.ucsb.edu> wrote:
>
> So I did some digging and according to the diagram in the link below,
> the observed behavior is correct.
>
> http://book.chinaunix.net/special/ebook/oreilly/Understanding_Linux_Network_Internals/
>
> Prior to passing frames to the br_handle_frame_hook, the frames are
> duplicated and sent to the registered sniffers.  However, once the
> frames are sent to the bridge handler they are not supposed to be passed
> to any protocols.  I did a few tests with arping and it does appear that
> the IP stack does not receive the frames once Click is running.
> However, the ARP requests can still be seen via tcpdump, confirming the
> behavior shown in the diagram.
>
> Roman
>
>
>
>
> On 05/06/2011 09:40 AM, Roman Chertov wrote:
> > So I spent some time on the issue I reported earlier with packets being visible
> > to the kernel IP stack when running kernel level Click.  I have installed a
> > plain vanilla kernel 2.6.35.9 on my Fedora14 box, and ran the following config.
> >
> > FromDevice(eth12) ->  Print ->  Discard;
> >
> > I have also ran tcpdump -i eth12.  The packets that were sent to the machine
> > were captured by tcpdump, which definitely should not have happened.  Looks like
> > the br_handle_frame_hook capture method gets the packets after they get on the
> > way to the kernel IP stack.  This behavior is definitely not good for some
> > kernel level configs as the kernel IP stack should not be involved in packet
> > processing at all.
> >
> > By the way, Joonwoo reported the same issue on his Ubuntu setup.
> >
> > Roman
> >
> >
> > _______________________________________________
> > click mailing list
> > click at amsterdam.lcs.mit.edu
> > https://amsterdam.lcs.mit.edu/mailman/listinfo/click
> >
>
> _______________________________________________
> click mailing list
> click at amsterdam.lcs.mit.edu
> https://amsterdam.lcs.mit.edu/mailman/listinfo/click