Toni Peltonen <pel...@peltzi.fi> wrote:
>Previously when unbinding a slave the 802.3ad implementation only told
>partner that the port is not suitable for aggregation by setting the port
>aggregation state from aggregatable to individual. This is not enough. If the
>physical layer still stays up and we only unbinded this port from the bond
>there
>is nothing in the aggregation status alone to prevent the partner from sending
>traffic towards us. To ensure that the partner doesn't consider this
>port at all anymore we should also disable collecting and distributing to
>signal that this actor is going away.
>
>I have tested this behaviour againts Arista EOS switches with mlx5 cards
>(physical link stays up when even when interface is down) and simulated
>the same situation virtually Linux <-> Linux with two network namespaces
>running two veth device pairs. In both cases setting aggregation to
>individual doesn't alone prevent traffic from being to sent towards this
>port given that the link stays up in partners end. Partner still keeps
>it's end in collecting + distributing state and continues until timeout is
>reached. In most cases this means we are losing the traffic partner sends
>towards our port while we wait for timeout. This is most visible with slow
>periodic time (LAPC rate slow).
"LAPC" -> "LACP"
>Other open source implementations like Open VSwitch and libreswitch, and
>vendor implementations like Arista EOS, seem to disable collecting +
>distributing to when doing similar port disabling/detaching/removing change.
>With this patch kernel implementation would behave the same way and ensure
>partner doesn't consider our actor viable anymore.
After re-reading the relevant bits of 802.1AX (particularly
5.4.9 on recordPDU and update_Selected) I'm going to suggest also
clearing AD_STATE_SYNCHRONIZATION, based on:
Partner_Oper_Port_State.Synchronization is also set to TRUE if
the value of Actor_State.Aggregation in the received PDU is set
to FALSE (i.e., indicates an Individual link),
Actor_State.Synchronization in the received PDU is set to TRUE,
and LACP will actively maintain the link.
Per the above, learing _SYNC in the LACPDU should un-sync the
port, inducing the Mux state machine (figure 5-15) to exit C_D state and
go to ATTACHED state (disabling Coll/Dist).
But, either way, as this is a hint to get the link partner to
stop using the port, this looks reasonable to me.
Acked-by: Jay Vosburgh <jay.vosbu...@canonical.com>
-J
>Signed-off-by: Toni Peltonen <pel...@peltzi.fi>
>---
> drivers/net/bonding/bond_3ad.c | 2 ++
> 1 file changed, 2 insertions(+)
>
>diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
>index f43fb2f958a5..6776c33753dc 100644
>--- a/drivers/net/bonding/bond_3ad.c
>+++ b/drivers/net/bonding/bond_3ad.c
>@@ -2086,6 +2086,8 @@ void bond_3ad_unbind_slave(struct slave *slave)
> aggregator->aggregator_identifier);
>
> /* Tell the partner that this port is not suitable for aggregation */
>+ port->actor_oper_port_state &= ~AD_STATE_COLLECTING;
>+ port->actor_oper_port_state &= ~AD_STATE_DISTRIBUTING;
> port->actor_oper_port_state &= ~AD_STATE_AGGREGATION;
> __update_lacpdu_from_port(port);
> ad_lacpdu_send(port);
>--
>2.19.0
---
-Jay Vosburgh, jay.vosbu...@canonical.com
