Justin Iurman e4f6de68de net: lwtunnel: fix recursion loops
[ Upstream commit 986ffb3a57c5650fb8bf6d59a8f0f07046abfeb6 ]

This patch acts as a parachute, catch all solution, by detecting
recursion loops in lwtunnel users and taking care of them (e.g., a loop
between routes, a loop within the same route, etc). In general, such
loops are the consequence of pathological configurations. Each lwtunnel
user is still free to catch such loops early and do whatever they want
with them. It will be the case in a separate patch for, e.g., seg6 and
seg6_local, in order to provide drop reasons and update statistics.
Another example of a lwtunnel user taking care of loops is ioam6, which
has valid use cases that include loops (e.g., inline mode), and which is
addressed by the next patch in this series. Overall, this patch acts as
a last resort to catch loops and drop packets, since we don't want to
leak something unintentionally because of a pathological configuration
in lwtunnels.

The solution in this patch reuses dev_xmit_recursion(),
dev_xmit_recursion_inc(), and dev_xmit_recursion_dec(), which seems fine
considering the context.

Closes: https://lore.kernel.org/netdev/2bc9e2079e864a9290561894d2a602d6@akamai.com/
Closes: https://lore.kernel.org/netdev/Z7NKYMY7fJT5cYWu@shredder/
Fixes: ffce41962e ("lwtunnel: support dst output redirect function")
Fixes: 2536862311 ("lwt: Add support to redirect dst.input")
Fixes: 14972cbd34 ("net: lwtunnel: Handle fragmentation")
Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Link: https://patch.msgid.link/20250314120048.12569-2-justin.iurman@uliege.be
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-28 21:59:53 +01:00
2025-03-28 21:59:53 +01:00
2025-03-22 12:50:50 -07:00

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.
Description
No description provided
Readme 7.9 GiB
Languages
C 97.7%
Assembly 1.6%
Makefile 0.3%
Perl 0.1%