Danielle Ratson a3f88d89f6 selftests: net: Add tests for ARP probe and DAD NS handling
Add test cases to verify that ARP probes and DAD Neighbor Solicitations
are handled correctly by the bridge neighbor suppression feature.

When neighbor suppression is enabled on a bridge VXLAN port, the bridge
should reply to ARP/NS messages on behalf of remote hosts when both FDB
and neighbor entries exist, and the answer is known. However, when
either the FDB or the neighbor exists, ARP probes / DAD NS should be
treated like regular ARP requests / NS and flood to VXLAN.

Add two new test functions:

neigh_suppress_arp_probe(): Tests ARP probe handling by triggering
duplicate address detection using arping -D. Verifies that probes are
flooded when the bridge doesn't know the answer, and suppressed when FDB
and neighbor entries exist.

neigh_suppress_dad_ns(): Tests DAD NS handling by constructing DAD NS
packets using mausezahn and verifies correct flooding/suppression
behavior.

Before the previous patch:

$ ./test_bridge_neigh_suppress.sh -t "neigh_suppress_arp_probe neigh_suppress_dad_ns"

Per-port ARP probe suppression
------------------------------
TEST: ARP probe suppression                                         [ OK ]
TEST: "neigh_suppress" is on                                        [ OK ]
TEST: ARP probe suppression                                         [FAIL]
TEST: FDB and neighbor entry installation                           [ OK ]
TEST: arping                                                        [FAIL]
TEST: ARP probe suppression                                         [FAIL]
TEST: neighbor removal                                              [ OK ]
TEST: ARP probe suppression                                         [FAIL]
TEST: "neigh_suppress" is off                                       [ OK ]
TEST: ARP probe suppression                                         [FAIL]

Per-port DAD NS suppression
---------------------------
TEST: DAD NS suppression                                            [ OK ]
TEST: "neigh_suppress" is on                                        [ OK ]
TEST: DAD NS suppression                                            [FAIL]
TEST: FDB and neighbor entry installation                           [ OK ]
TEST: DAD NS suppression                                            [FAIL]
TEST: neighbor removal                                              [ OK ]
TEST: DAD NS suppression                                            [FAIL]
TEST: DAD NS proxy NA reply                                         [FAIL]
TEST: "neigh_suppress" is off                                       [ OK ]
TEST: DAD NS suppression                                            [FAIL]

Tests passed:   10
Tests failed:   10

After the previous patch:

$ ./test_bridge_neigh_suppress.sh -t "neigh_suppress_arp_probe neigh_suppress_dad_ns"

Per-port ARP probe suppression
------------------------------
TEST: ARP probe suppression                                         [ OK ]
TEST: "neigh_suppress" is on                                        [ OK ]
TEST: ARP probe suppression                                         [ OK ]
TEST: FDB and neighbor entry installation                           [ OK ]
TEST: arping                                                        [ OK ]
TEST: ARP probe suppression                                         [ OK ]
TEST: neighbor removal                                              [ OK ]
TEST: ARP probe suppression                                         [ OK ]
TEST: "neigh_suppress" is off                                       [ OK ]
TEST: ARP probe suppression                                         [ OK ]

Per-port DAD NS suppression
---------------------------
TEST: DAD NS suppression                                            [ OK ]
TEST: "neigh_suppress" is on                                        [ OK ]
TEST: DAD NS suppression                                            [ OK ]
TEST: FDB and neighbor entry installation                           [ OK ]
TEST: DAD NS suppression                                            [ OK ]
TEST: neighbor removal                                              [ OK ]
TEST: DAD NS suppression                                            [ OK ]
TEST: DAD NS proxy NA reply                                         [ OK ]
TEST: "neigh_suppress" is off                                       [ OK ]
TEST: DAD NS suppression                                            [ OK ]

Tests passed:  20
Tests failed:   0

Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260429062405.1386417-3-danieller@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-30 17:35:17 -07:00
2026-01-26 19:07:09 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2026-04-26 14:19:00 -07:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros
* AI Coding Assistant - LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst
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