73dd98ac19
[ Upstream commit 0c51e12e218f20b7d976158fdc18019627326f7a ] In case user space sends a packet destined to a broadcast address when a matching broadcast route is not configured, the kernel will create a unicast neighbour entry that will never be resolved [1]. When the broadcast route is configured, the unicast neighbour entry will not be invalidated and continue to linger, resulting in packets being dropped. Solve this by invalidating unresolved neighbour entries for broadcast addresses after routes for these addresses are internally configured by the kernel. This allows the kernel to create a broadcast neighbour entry following the next route lookup. Another possible solution that is more generic but also more complex is to have the ARP code register a listener to the FIB notification chain and invalidate matching neighbour entries upon the addition of broadcast routes. It is also possible to wave off the issue as a user space problem, but it seems a bit excessive to expect user space to be that intimately familiar with the inner workings of the FIB/neighbour kernel code. [1] https://lore.kernel.org/netdev/55a04a8f-56f3-f73c-2aea-2195923f09d1@huawei.com/ Reported-by: Wang Hai <wanghai38@huawei.com> Signed-off-by: Ido Schimmel <idosch@nvidia.com> Tested-by: Wang Hai <wanghai38@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.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 Restructured Text 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.