94f748fd4e
[ Upstream commit f4156f9656feac21f4de712fac94fae964c5d402 ]
The announcement messages of batman-adv COMPAT_VERSION 15 have the
possibility to announce additional information via a dynamic TVLV part.
This part is optional for the ELP packets and currently not parsed by the
Linux implementation. Still out-of-tree versions are using it to transport
things like neighbor hashes to optimize the rebroadcast behavior.
Since the ELP broadcast packets are smaller than the minimal ethernet
packet, it often has to be padded. This is often done (as specified in
RFC894) with octets of zero and thus work perfectly fine with the TVLV
part (making it a zero length and thus empty). But not all ethernet
compatible hardware seems to follow this advice. To avoid ambiguous
situations when parsing the TVLV header, just force the 4 bytes (TVLV
length + padding) after the required ELP header to zero.
Fixes: d6f94d91f766 ("batman-adv: ELP - adding basic infrastructure")
Reported-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.