Documentation/userspace-api/netlink/netlink-raw.rst

Source file repositories/reference/linux-study-clean/Documentation/userspace-api/netlink/netlink-raw.rst

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System: Linux kernel
Corpus path: Documentation/userspace-api/netlink/netlink-raw.rst
Extension: .rst
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Lines: 195
Domain: Support Tooling And Documentation
Bucket: Documentation
Inferred role: Support Tooling And Documentation: documentation
Status: atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

No C-style include directives detected by the generator.

Detected Declarations

No top-level syscall, struct, function, initcall, or export declaration detected by the generator.

Annotated Snippet

.. SPDX-License-Identifier: BSD-3-Clause

======================================================
Netlink specification support for raw Netlink families
======================================================

This document describes the additional properties required by raw Netlink
families such as ``NETLINK_ROUTE`` which use the ``netlink-raw`` protocol
specification.

Specification
=============

The netlink-raw schema extends the :doc:`genetlink-legacy <genetlink-legacy>`
schema with properties that are needed to specify the protocol numbers and
multicast IDs used by raw netlink families. See :ref:`classic_netlink` for more
information. The raw netlink families also make use of type-specific
sub-messages.

Globals
-------

protonum
~~~~~~~~

The ``protonum`` property is used to specify the protocol number to use when
opening a netlink socket.

.. code-block:: yaml

  # SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)

  name: rt-addr
  protocol: netlink-raw
  protonum: 0             # part of the NETLINK_ROUTE protocol


Multicast group properties
--------------------------

value
~~~~~

The ``value`` property is used to specify the group ID to use for multicast
group registration.

.. code-block:: yaml

  mcast-groups:
    list:
      -
        name: rtnlgrp-ipv4-ifaddr
        value: 5
      -
        name: rtnlgrp-ipv6-ifaddr
        value: 9
      -
        name: rtnlgrp-mctp-ifaddr
        value: 34

Sub-messages
------------

Several raw netlink families such as
:ref:`rt-link<netlink-rt-link>` and
:ref:`tc<netlink-tc>` use attribute nesting as an
abstraction to carry module specific information.

Conceptually it looks as follows::

Annotation

Atlas domain: Support Tooling And Documentation / Documentation.
Implementation status: atlas-only.

Implementation Notes

This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.