[Bridge] 802.1q packets

Patrick McHardy kaber at trash.net
Tue Jul 1 08:10:08 PDT 2008

richardvoigt at gmail.com wrote:
> On Mon, Jun 30, 2008 at 5:07 PM, Fulvio Ricciardi <
> fulvio.ricciardi at zeroshell.net> wrote:
>>> That mostly rules out other devices in the path as the
>>> cause of the problem.  There's just one chance of a
>>> netfilter interaction that I can think of: netfilter may
>>> cause fragments to be recombined, without netfilter the
>>> fragments could be bridged.  Are you running the ping
>>> command from the bridge itself, or across the bridge? (I
>>> presume across the bridge because you are discussing the
>>> FORWARD chain only)
>> I ping across the bridge. If instead a ping from the bridge
>> itself, all works right.
>>> Do the large ping requests show up in the iptables
>>> counters?
>> Yes, in any case (either ping -s 1472 and ping -s 1473) the
>> packets are counted in the FORWARD chain.
>>> What happens if you set no fragmentation when you run
>>> ping?
>> it's the same
> Just to verify, you mean that with no fragmentation, large pings go through
> if and only if bridge-nf-call-iptables is disabled?

Just FYI for all affected, I'm looking into this. One
problem is that only packets with skb->protocol == ETH_P_IP
are refragmented, but not ETH_P_8021Q. That change alone
doesn't fix it though, still trying to track it down.

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