4afc41dfa5
This counter increments when nf_conntrack_in sees a packet that already has a conntrack attached or when the packet is marked as UNTRACKED. Neither is an error. The former is normal for loopback traffic. The second happens for certain ICMPv6 packets or when nftables/ip(6)tables rules are in place. In case someone needs to count UNTRACKED packets, or packets that are marked as untracked before conntrack_in this can be done with both nftables and ip(6)tables rules. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.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.