netdev - Re: [net-next v3 0/9] net: bridge: cfm: Add support for Connectivity Fault Management(CFM)

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Date:   Tue, 6 Oct 2020 15:00:05 +0000
From:   Nikolay Aleksandrov <nikolay@...dia.com>
To:     "bridge@...ts.linux-foundation.org" 
        <bridge@...ts.linux-foundation.org>,
        "henrik.bjoernlund@...rochip.com" <henrik.bjoernlund@...rochip.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Roopa Prabhu <roopa@...dia.com>,
        "idosch@...lanox.com" <idosch@...lanox.com>,
        "jiri@...nulli.us" <jiri@...nulli.us>,
        "UNGLinuxDriver@...rochip.com" <UNGLinuxDriver@...rochip.com>,
        "kuba@...nel.org" <kuba@...nel.org>
Subject: Re: [net-next v3 0/9] net: bridge: cfm: Add support for Connectivity
 Fault Management(CFM)

On Tue, 2020-10-06 at 14:53 +0000, Henrik Bjoernlund wrote:
> Connectivity Fault Management (CFM) is defined in 802.1Q section 12.14.
> 
> Connectivity Fault Management (CFM) comprises capabilities for detecting, verifying,
> and isolating connectivity failures in Virtual Bridged Networks.
> These capabilities can be used in networks operated by multiple independent organizations,
> each with restricted management access to each other’s equipment.
> 
> CFM functions are partitioned as follows:
>     — Path discovery
>     — Fault detection
>     — Fault verification and isolation
>     — Fault notification
>     — Fault recovery
> 
> The primary CFM protocol shims are called Maintenance Points (MPs).
> A MP can be either a MEP or a MHF.
> The MEP:
>     -It is the Maintenance association End Point
>      described in 802.1Q section 19.2.
>     -It is created on a specific level (1-7) and is assuring
>      that no CFM frames are passing through this MEP on lower levels.
>     -It initiates and terminates/validates CFM frames on its level.
>     -It can only exist on a port that is related to a bridge.
> The MHF:
>     -It is the Maintenance Domain Intermediate Point
>      (MIP) Half Function (MHF) described in 802.1Q section 19.3.
>     -It is created on a specific level (1-7).
>     -It is extracting/injecting certain CFM frame on this level.
>     -It can only exist on a port that is related to a bridge.
>     -Currently not supported.
> 
> There are defined the following CFM protocol functions:
>     -Continuity Check
>     -Loopback. Currently not supported.
>     -Linktrace. Currently not supported.
> 
> This CFM component supports create/delete of MEP instances and configuration of
> the different CFM protocols. Also status information can be fetched and delivered
> through notification due to defect status change.
> 
> The user interacts with CFM using the 'cfm' user space client program,
> the client talks with the kernel using netlink.
> 
> Any notification emitted by CFM from the kernel can be monitored in user space
> by starting 'cfm_server' program.
> 
> Currently this 'cfm' and 'cfm_server' programs are standalone placed in a cfm
> repository https://github.com/microchip-ung/cfm but it is considered to integrate
> this into 'iproute2'.
> 
> v2 -> v3
>     The switchdev definition and utilization has been removed as there was no
>     switchdev implementation.
>     Some compiling issues are fixed as Reported-by: kernel test robot <lkp@...el.com>.
> 

Well, funny timing. :) I just finished reviewing v2 half an hour ago. All of my
comments for v2 apply for this v3 set, sorry but you'll have to fix a few more
issues.

Thanks,
 Nik