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7d8dc1c7be
Conntrack assumes an unconfirmed entry (not yet committed to global hash
table) has a refcount of 1 and is not visible to other cores.
With multicast forwarding this assumption breaks down because such
skbs get cloned after being picked up, i.e. ct->use refcount is > 1.
Likewise, bridge netfilter will clone broad/mutlicast frames and
all frames in case they need to be flood-forwarded during learning
phase.
For ip multicast forwarding or plain bridge flood-forward this will
"work" because packets don't leave softirq and are implicitly
serialized.
With nfqueue this no longer holds true, the packets get queued
and can be reinjected in arbitrary ways.
Disable this feature, I see no other solution.
After this patch, nfqueue cannot queue packets except the last
multicast/broadcast packet.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.