netdev - Re: [PATCH iproute2 5/6] man8/bridge.8: explain self vs master for "bridge fdb add"

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Date:   Mon, 15 Feb 2021 09:22:47 +0100
From:   Alexandra Winter <wintera@...ux.ibm.com>
To:     Vladimir Oltean <olteanv@...il.com>,
        David Ahern <dsahern@...il.com>, netdev@...r.kernel.org
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Jiri Pirko <jiri@...nulli.us>,
        Ido Schimmel <idosch@...sch.org>,
        DENG Qingfang <dqfext@...il.com>,
        Tobias Waldekranz <tobias@...dekranz.com>,
        Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <nikolay@...dia.com>,
        Stephen Hemminger <stephen@...workplumber.org>
Subject: Re: [PATCH iproute2 5/6] man8/bridge.8: explain self vs master for
 "bridge fdb add"

Thank you very much Vladimir for improving this man page. I am still struggling with the meaning of the bridge attributes and sometimes
the man page has caused more confusion.

In the section about 'bridge link set' Self vs master mention physical device vs software bridge. Would it make sense to use the same
terminology here?

The attributes are listed under 'bridge fdb add' not under 'bridge fdb show'. Is it correct that the attributes displayed by 'show'
are a 1-to-1 representation of the ones set by 'add'? What about the entries that are not manually set, like bridge learned adresses?
Is it possible to add some explanation about those as well?

On 11.02.21 11:45, Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.oltean@....com>
> 
> The "usually hardware" and "usually software" distinctions make no
> sense, try to clarify what these do based on the actual kernel behavior.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
> ---
>  man/man8/bridge.8 | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/man/man8/bridge.8 b/man/man8/bridge.8
> index 1dc0aec83f09..d0bcd708bb61 100644
> --- a/man/man8/bridge.8
> +++ b/man/man8/bridge.8
> @@ -533,12 +533,21 @@ specified.
>  .sp
>  
>  .B self
> -- the address is associated with the port drivers fdb. Usually hardware
> -  (default).
> +- the operation is fulfilled directly by the driver for the specified network
> +device. If the network device belongs to a master like a bridge, then the
> +bridge is bypassed and not notified of this operation (and if the device does
> +notify the bridge, it is driver-specific behavior and not mandated by this
> +flag, check the driver for more details). The "bridge fdb add" command can also
> +be used on the bridge device itself, and in this case, the added fdb entries
> +will be locally terminated (not forwarded). In the latter case, the "self" flag
> +is mandatory. 
Maybe I misunderstand this sentence, but I can do a 'bridge fdb add' without 'self'
on the bridge device. And the address shows up under 'bridge fdb show'.
So what does mandatory mean here?
The flag is set by default if "master" is not specified.
>  .sp
>  
>  .B master
> -- the address is associated with master devices fdb. Usually software.
> +- if the specified network device is a port that belongs to a master device
> +such as a bridge, the operation is fulfilled by the master device's driver,
> +which may in turn notify the port driver too of the address. If the specified
> +device is a master itself, such as a bridge, this flag is invalid.
>  .sp
>  
>  .B router
>