2794cdb0b9
At this time, every new conntrack gets the 'event cache extension' enabled for it. This is because the 'net.netfilter.nf_conntrack_events' sysctl defaults to 1. Changing the default to 0 means that commands that rely on the event notification extension, e.g. 'conntrack -E' or conntrackd, stop working. We COULD detect if there is a listener by means of 'nfnetlink_has_listeners()' and only add the extension if this is true. The downside is a dependency from conntrack module to nfnetlink module. This adds a different way: inc/dec a counter whenever a ctnetlink group is being (un)subscribed and toggle a flag in struct net. Next patches will take advantage of this and will only add the event extension if the flag is set. 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.