Re: [PATCH v8 net-next 02/12] net: bridge: add blackhole fdb entry flag

From: netdev@kapio-technology.com
To: Ido Schimmel <idosch@nvidia.com>
Cc: davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org,
	Florian Fainelli <f.fainelli@gmail.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	Eric Dumazet <edumazet@google.com>,
	Paolo Abeni <pabeni@redhat.com>,
	Kurt Kanzenbach <kurt@linutronix.de>,
	Hauke Mehrtens <hauke@hauke-m.de>,
	Woojung Huh <woojung.huh@microchip.com>,
	UNGLinuxDriver@microchip.com, Sean Wang <sean.wang@mediatek.com>,
	Landen Chao <Landen.Chao@mediatek.com>,
	DENG Qingfang <dqfext@gmail.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Claudiu Manoil <claudiu.manoil@nxp.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Jiri Pirko <jiri@resnulli.us>, Ivan Vecera <ivecera@redhat.com>,
	Roopa Prabhu <roopa@nvidia.com>,
	Nikolay Aleksandrov <razor@blackwall.org>,
	Shuah Khan <shuah@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	Christian Marangi <ansuelsmth@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Yuwei Wang <wangyuweihx@gmail.com>,
	Petr Machata <petrm@nvidia.com>,
	Florent Fourcot <florent.fourcot@wifirst.fr>,
	Hans Schultz <schultz.hans@gmail.com>,
	Joachim Wiberg <troglobit@gmail.com>,
	Amit Cohen <amcohen@nvidia.com>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	bridge@lists.linux-foundation.org,
	linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v8 net-next 02/12] net: bridge: add blackhole fdb entry flag
Date: Thu, 20 Oct 2022 21:34:05 +0200	[thread overview]
Message-ID: <40edb67ac71ba7eef428c8366753ae94@kapio-technology.com> (raw)
In-Reply-To: <Y1FHuXE+X/V9aRvh@shredder>

On 2022-10-20 15:06, Ido Schimmel wrote:
> On Tue, Oct 18, 2022 at 06:56:09PM +0200, Hans J. Schultz wrote:
>> Add a 'blackhole' fdb flag, ensuring that no forwarding from any port
>> to a destination MAC that has a FDB entry with this flag on will 
>> occur.
>> The packets will thus be dropped.
>> 
>> When the blackhole fdb flag is set, the 'local' flag will also be 
>> enabled
>> as blackhole entries are not associated with any port.
> 
> It reads as if the kernel will enable the 'local' flag automatically,
> which is not true anymore. The bridge driver enforces that
> 'NUD_PERMANENT' is set if 'NTF_EXT_BLACKHOLE' is specified.
> 
>> 
>> Thus the command will be alike to:
>> bridge fdb add MAC dev br0 local blackhole
>> 
>> Signed-off-by: Hans J. Schultz <netdev@kapio-technology.com>
> 
> Looks OK to me. See one comment below.
> 
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> 
> [...]
> 
>> @@ -1140,7 +1148,7 @@ static int __br_fdb_add(struct ndmsg *ndm, 
>> struct net_bridge *br,
>>  		err = br_fdb_external_learn_add(br, p, addr, vid, true);
>>  	} else {
>>  		spin_lock_bh(&br->hash_lock);
>> -		err = fdb_add_entry(br, p, addr, ndm, nlh_flags, vid, nfea_tb);
>> +		err = fdb_add_entry(br, p, addr, ndm, nlh_flags, vid, ext_flags, 
>> nfea_tb);
> 
> I believe the preference is to wrap to 80 columns when possible.

Ok, I only have knowledge of 100 columns as a limit.

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