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Date:   Sun, 31 Jan 2021 02:33:33 +0200
From:   Vladimir Oltean <olteanv@gmail.com>
To:     Tobias Waldekranz <tobias@waldekranz.com>
Cc:     DENG Qingfang <dqfext@gmail.com>, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net: dsa: mv88e6xxx: override existent unicast
 portvec in port_fdb_add
Message-ID: <20210131003333.5lhacwr4usd3dv2l@skbuf>
References: <20210130134334.10243-1-dqfext@gmail.com>
 <87eei25f09.fsf@waldekranz.com>
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On Sat, Jan 30, 2021 at 09:47:02PM +0100, Tobias Waldekranz wrote:
> root@envoy:~# bridge fdb add 02:00:de:ad:00:01 dev eth1 static vlan 1
> Why does the second add operation succeed? Am I missing some magic flag?

Yes, 'master'.
We talked about this before. 'bridge fdb add' is implicitly 'self' which
bypasses the bridge code and shoots straight for the .ndo_fdb_add that
DSA implements. Maybe we should just kill that to avoid further
confusion.

$ bridge link
6: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 master br0 state disabled priority 32 cost 100
7: eth1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 master br0 state disabled priority 32 cost 100
10: swp5@eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br0 state forwarding priority 32 cost 4
11: swp2@eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br0 state forwarding priority 32 cost 4
12: swp3@eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br0 state forwarding priority 32 cost 4
13: swp4@eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br0 state forwarding priority 32 cost 4
$ bridge fdb add 00:01:02:03:04:05 dev eth0 master static
$ bridge fdb add 00:01:02:03:04:05 dev eth1 master static
RTNETLINK answers: File exists