7ca3a1b0f4
[ Upstream commit 7890cbea66e78a3a6037b2a12827118d7243270b ]
This allows to replace a tcp option with nop padding to selectively disable
a particular tcp option.
Optstrip mode is chosen when userspace passes the exthdr expression with
neither a source nor a destination register attribute.
This is identical to xtables TCPOPTSTRIP extension.
The only difference is that TCPOPTSTRIP allows to pass in a bitmap
of options to remove rather than a single number.
Unlike TCPOPTSTRIP this expression can be used multiple times
in the same rule to get the same effect.
We could add a new nested attribute later on in case there is a
use case for single-expression-multi-remove.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Stable-dep-of: 28427f368f0e ("netfilter: nft_exthdr: Fix non-linear header modification")
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.