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There are multiple ICMP rate limiting mechanisms: * Global limits: net.ipv4.icmp_msgs_burst/icmp_msgs_per_sec * v4 per-host limits: net.ipv4.icmp_ratelimit/ratemask * v6 per-host limits: net.ipv6.icmp_ratelimit/ratemask However, when ICMP output is limited, there is no way to tell which limit has been hit or even if the limits are responsible for the lack of ICMP output. Add counters for each of the cases above. As we are within local_bh_disable(), use the __INC stats variant. Example output: # nstat -sz "*RateLimit*" IcmpOutRateLimitGlobal 134 0.0 IcmpOutRateLimitHost 770 0.0 Icmp6OutRateLimitHost 84 0.0 Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com> Suggested-by: Abhishek Rawal <rawal.abhishek92@gmail.com> Link: https://lore.kernel.org/r/273b32241e6b7fdc5c609e6f5ebc68caf3994342.1674605770.git.jamie.bainbridge@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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.