linux-kernel - Re: [PATCH v2 net-next 2/4] net: switchdev: add support for offloading of fdb locked flag

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Date:   Wed, 23 Mar 2022 13:49:32 +0100
From:   Hans Schultz <schultz.hans@...il.com>
To:     Vladimir Oltean <olteanv@...il.com>,
        Hans Schultz <schultz.hans@...il.com>
Cc:     davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.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>,
        Daniel Borkmann <daniel@...earbox.net>,
        Ido Schimmel <idosch@...dia.com>, linux-kernel@...r.kernel.org,
        bridge@...ts.linux-foundation.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v2 net-next 2/4] net: switchdev: add support for
 offloading of fdb locked flag

On ons, mar 23, 2022 at 14:35, Vladimir Oltean <olteanv@...il.com> wrote:
> On Wed, Mar 23, 2022 at 01:29:52PM +0100, Hans Schultz wrote:
>> On tor, mar 17, 2022 at 10:39, Hans Schultz <schultz.hans@...il.com> wrote:
>> > Used for Mac-auth/MAB feature in the offloaded case.
>> >
>> > Signed-off-by: Hans Schultz <schultz.hans+netdev@...il.com>
>> > ---
>> >  include/net/switchdev.h | 3 ++-
>> >  net/bridge/br.c         | 3 ++-
>> >  net/bridge/br_fdb.c     | 7 +++++--
>> >  net/bridge/br_private.h | 2 +-
>> >  4 files changed, 10 insertions(+), 5 deletions(-)
>> >
>> > diff --git a/include/net/switchdev.h b/include/net/switchdev.h
>> > index 3e424d40fae3..d5d923411f5e 100644
>> > --- a/include/net/switchdev.h
>> > +++ b/include/net/switchdev.h
>> > @@ -229,7 +229,8 @@ struct switchdev_notifier_fdb_info {
>> >  	u16 vid;
>> >  	u8 added_by_user:1,
>> >  	   is_local:1,
>> > -	   offloaded:1;
>> > +	   offloaded:1,
>> > +	   locked:1;
>> >  };
>> >  
>> >  struct switchdev_notifier_port_obj_info {
>> > diff --git a/net/bridge/br.c b/net/bridge/br.c
>> > index b1dea3febeea..adcdbecbc218 100644
>> > --- a/net/bridge/br.c
>> > +++ b/net/bridge/br.c
>> > @@ -166,7 +166,8 @@ static int br_switchdev_event(struct notifier_block *unused,
>> >  	case SWITCHDEV_FDB_ADD_TO_BRIDGE:
>> >  		fdb_info = ptr;
>> >  		err = br_fdb_external_learn_add(br, p, fdb_info->addr,
>> > -						fdb_info->vid, false);
>> > +						fdb_info->vid, false,
>> > +						fdb_info->locked);
>> >  		if (err) {
>> >  			err = notifier_from_errno(err);
>> >  			break;
>> > diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
>> > index 57ec559a85a7..57aa1955d34d 100644
>> > --- a/net/bridge/br_fdb.c
>> > +++ b/net/bridge/br_fdb.c
>> > @@ -987,7 +987,7 @@ static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge *br,
>> >  					   "FDB entry towards bridge must be permanent");
>> >  			return -EINVAL;
>> >  		}
>> > -		err = br_fdb_external_learn_add(br, p, addr, vid, true);
>> > +		err = br_fdb_external_learn_add(br, p, addr, vid, true,
>> >  false);
>> 
>> Does someone have an idea why there at this point is no option to add a
>> dynamic fdb entry?
>> 
>> The fdb added entries here do not age out, while the ATU entries do
>> (after 5 min), resulting in unsynced ATU vs fdb.
>
> I think the expectation is to use br_fdb_external_learn_del() if the
> externally learned entry expires. The bridge should not age by itself
> FDB entries learned externally.
>

It seems to me that something is missing then?
My tests using trafgen that I gave a report on to Lunn generated massive
amounts of fdb entries, but after a while the ATU was clean and the fdb
was still full of random entries...

>> >  	} else {
>> >  		spin_lock_bh(&br->hash_lock);
>> >  		err = fdb_add_entry(br, p, addr, ndm, nlh_flags, vid, nfea_tb);
>> > @@ -1216,7 +1216,7 @@ void br_fdb_unsync_static(struct net_bridge *br, struct net_bridge_port *p)
>> >  
>> >  int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
>> >  			      const unsigned char *addr, u16 vid,
>> > -			      bool swdev_notify)
>> > +			      bool swdev_notify, bool locked)
>> >  {
>> >  	struct net_bridge_fdb_entry *fdb;
>> >  	bool modified = false;
>> > @@ -1236,6 +1236,9 @@ int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
>> >  		if (!p)
>> >  			flags |= BIT(BR_FDB_LOCAL);
>> >  
>> > +		if (locked)
>> > +			flags |= BIT(BR_FDB_ENTRY_LOCKED);
>> > +
>> >  		fdb = fdb_create(br, p, addr, vid, flags);
>> >  		if (!fdb) {
>> >  			err = -ENOMEM;
>> > diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
>> > index f5a0b68c4857..3275e33b112f 100644
>> > --- a/net/bridge/br_private.h
>> > +++ b/net/bridge/br_private.h
>> > @@ -790,7 +790,7 @@ int br_fdb_sync_static(struct net_bridge *br, struct net_bridge_port *p);
>> >  void br_fdb_unsync_static(struct net_bridge *br, struct net_bridge_port *p);
>> >  int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
>> >  			      const unsigned char *addr, u16 vid,
>> > -			      bool swdev_notify);
>> > +			      bool swdev_notify, bool locked);
>> >  int br_fdb_external_learn_del(struct net_bridge *br, struct net_bridge_port *p,
>> >  			      const unsigned char *addr, u16 vid,
>> >  			      bool swdev_notify);
>> > -- 
>> > 2.30.2