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8bfb74ae12
This patch uses zero as timeout marker for those elements that never expire when the element is created. If userspace provides no timeout for an element, then the default set timeout applies. However, if no default set timeout is specified and timeout flag is set on, then timeout extension is allocated and timeout is set to zero to allow for future updates. Use of zero a never timeout marker has been suggested by Phil Sutter. Note that, in older kernels, it is already possible to define elements that never expire by declaring a set with the set timeout flag set on and no global set timeout, in this case, new element with no explicit timeout never expire do not allocate the timeout extension, hence, they never expire. This approach makes it complicated to accomodate element timeout update, because element extensions do not support reallocations. Therefore, allocate the timeout extension and use the new marker for this case, but do not expose it to userspace to retain backward compatibility in the set listing. 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 reStructuredText 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.