linux-kernel - Re: [PATCH v8 net-next 10/12] net: dsa: mv88e6xxx: mac-auth/MAB implementation

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Date:   Fri, 21 Oct 2022 19:30:05 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     netdev@...io-technology.com
Cc:     davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org,
        Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>,
        Kurt Kanzenbach <kurt@...utronix.de>,
        Hauke Mehrtens <hauke@...ke-m.de>,
        Woojung Huh <woojung.huh@...rochip.com>,
        UNGLinuxDriver@...rochip.com, Sean Wang <sean.wang@...iatek.com>,
        Landen Chao <Landen.Chao@...iatek.com>,
        DENG Qingfang <dqfext@...il.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Claudiu Manoil <claudiu.manoil@....com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Jiri Pirko <jiri@...nulli.us>,
        Ivan Vecera <ivecera@...hat.com>,
        Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <razor@...ckwall.org>,
        Shuah Khan <shuah@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Christian Marangi <ansuelsmth@...il.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Yuwei Wang <wangyuweihx@...il.com>,
        Petr Machata <petrm@...dia.com>,
        Ido Schimmel <idosch@...dia.com>,
        Florent Fourcot <florent.fourcot@...irst.fr>,
        Hans Schultz <schultz.hans@...il.com>,
        Joachim Wiberg <troglobit@...il.com>,
        Amit Cohen <amcohen@...dia.com>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        bridge@...ts.linux-foundation.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v8 net-next 10/12] net: dsa: mv88e6xxx: mac-auth/MAB
 implementation

On Fri, Oct 21, 2022 at 03:16:21PM +0200, netdev@...io-technology.com wrote:
> As it is now in the bridge, the locked port part is handled before learning
> in the ingress data path, so with BR_LEARNING and BR_PORT_LOCKED, I think it
> will work as it does now except link local packages.

If link-local learning is enabled on a locked port, I think those
addresses should also be learned with the BR_FDB_LOCKED flag. The
creation of those locked FDB entries can be further suppressed by the
BROPT_NO_LL_LEARN flag.

> If your suggestion of BR_LEARNING causing BR_FDB_LOCKED on a locked port, I
> guess it would be implemented under br_fdb_update() and BR_LEARNING +
> BR_PORT_LOCKED would go together, forcing BR_LEARNING in this case, thus also
> for all drivers?

Yes, basically where this is placed right now (in br_handle_frame_finish):

	if (p->flags & BR_PORT_LOCKED) {
		struct net_bridge_fdb_entry *fdb_src =
			br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);

		if (!fdb_src) {
			unsigned long flags = 0;

			if (p->flags & BR_PORT_MAB) {
			   ~~~~~~~~~~~~~~~~~~~~~~~~
			   except check for BR_LEARNING

				__set_bit(BR_FDB_LOCKED, &flags);
				br_fdb_update(br, p, eth_hdr(skb)->h_source,
					      vid, flags);
			}
			goto drop;
		} else if (READ_ONCE(fdb_src->dst) != p ||
			   test_bit(BR_FDB_LOCAL, &fdb_src->flags) ||
			   test_bit(BR_FDB_LOCKED, &fdb_src->flags)) {
			goto drop;
		}
	}