Petr Machata cc7af1b89c net: ipv6: ip6mr: Fix in/out netdev to pass to the FORWARD chain
[ Upstream commit 3365afd3abda5f6a54f4a822dad5c9314e94c3fc ]

The netfilter hook is invoked with skb->dev for input netdevice, and
vif_dev for output netdevice. However at the point of invocation, skb->dev
is already set to vif_dev, and MR-forwarded packets are reported with
in=out:

 # ip6tables -A FORWARD -j LOG --log-prefix '[forw]'
 # cd tools/testing/selftests/net/forwarding
 # ./router_multicast.sh
 # dmesg | fgrep '[forw]'
 [ 1670.248245] [forw]IN=v5 OUT=v5 [...]

For reference, IPv4 MR code shows in and out as appropriate.
Fix by caching skb->dev and using the updated value for output netdev.

Fixes: 7bc570c8b4 ("[IPV6] MROUTE: Support multicast forwarding.")
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/3141ae8386fbe13fef4b793faa75e6bae58d798a.1750113335.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-08-15 12:08:45 +02:00
2025-08-15 12:08:40 +02:00
2025-08-15 12:08:42 +02:00
2022-09-28 09:02:20 +02:00
2025-08-01 09:47:33 +01:00

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.
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