Subject: [net][hsr] Question regarding HSR RedBox functionality implementation (preferably on KSZ9477)

From: Lukasz Majewski <[email-masked]>
Date: Tue, 9 Jan 2024 13:32:34 +0100

Dear Community,

I would like to ask you for some help regarding HSR mainline
implementation.

As of now for KSZ9477 we do have working hsr0 (as offloading HW) for
HSR ring operation and some other ports for this IC (like lan3,4,5).

With current setup it is possible to forward packets from HSR ring to
non-HSR network (i.e. plain ethernet) with L3 routing.

However, I'm wondering how the mainline Linux kernel could handle HSR
RedBox functionality (on document [1], Figure 2. we do have "bridge" -
OSI L2).

To be more interesting - br0 can be created between hsr0 and e.g. lan3.
But as expected communication breaks on both directions (to SAN and to
HSR ring).

Is there a similar functionality already present in the Linux kernel
(so this approach could be reused)?

My (very rough idea) would be to extend KSZ9477 bridge join functions
to check if HSR capable interface is "bridged" and then handle frames
in a special way.

However, I would like to first ask for as much input as possible - to
avoid any unnecessary work.

Thanks in advance for help :-)

Link:

[1] -
https://ww1.microchip.com/downloads/en/Appnotes/AN3474-KSZ9477-High-Availability-Seamless-Redundancy-Application-Note-00003474A.pdf

Best regards,

Lukasz Majewski

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