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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-08-07 13:11:22 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-08-07 13:11:22 +0000
commitb20732900e4636a467c0183a47f7396700f5f743 (patch)
tree42f079ff82e701ebcb76829974b4caca3e5b6798 /Documentation/userspace-api/netlink/netlink-raw.rst
parentAdding upstream version 6.8.12. (diff)
downloadlinux-b20732900e4636a467c0183a47f7396700f5f743.tar.xz
linux-b20732900e4636a467c0183a47f7396700f5f743.zip
Adding upstream version 6.9.7.upstream/6.9.7
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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diff --git a/Documentation/userspace-api/netlink/netlink-raw.rst b/Documentation/userspace-api/netlink/netlink-raw.rst
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--- a/Documentation/userspace-api/netlink/netlink-raw.rst
+++ b/Documentation/userspace-api/netlink/netlink-raw.rst
@@ -150,3 +150,45 @@ attributes from an ``attribute-set``. For example the following
Note that a selector attribute must appear in a netlink message before any
sub-message attributes that depend on it.
+
+If an attribute such as ``kind`` is defined at more than one nest level, then a
+sub-message selector will be resolved using the value 'closest' to the selector.
+For example, if the same attribute name is defined in a nested ``attribute-set``
+alongside a sub-message selector and also in a top level ``attribute-set``, then
+the selector will be resolved using the value 'closest' to the selector. If the
+value is not present in the message at the same level as defined in the spec
+then this is an error.
+
+Nested struct definitions
+-------------------------
+
+Many raw netlink families such as :doc:`tc<../../networking/netlink_spec/tc>`
+make use of nested struct definitions. The ``netlink-raw`` schema makes it
+possible to embed a struct within a struct definition using the ``struct``
+property. For example, the following struct definition embeds the
+``tc-ratespec`` struct definition for both the ``rate`` and the ``peakrate``
+members of ``struct tc-tbf-qopt``.
+
+.. code-block:: yaml
+
+ -
+ name: tc-tbf-qopt
+ type: struct
+ members:
+ -
+ name: rate
+ type: binary
+ struct: tc-ratespec
+ -
+ name: peakrate
+ type: binary
+ struct: tc-ratespec
+ -
+ name: limit
+ type: u32
+ -
+ name: buffer
+ type: u32
+ -
+ name: mtu
+ type: u32