Subject: Re: [PATCH net-next v2 3/5] bonding: fix incorrect lacp mux state when agg not active

From: Jay Vosburgh <[email-masked]>
Date: Mon, 26 Jan 2015 18:42:24 -0800

Jonathan Toppins <[email-masked]> wrote:

>From: Wilson Kok <[email-masked]>
>
>This patch attempts to fix the following problems when an actor or
>partner's aggregator is not active:
>    1. a slave's lacp port state is marked as AD_STATE_SYNCHRONIZATION
>       even if it is attached to an inactive aggregator. LACP advertises
>       this state to the partner, making the partner think he can move
>       into COLLECTING_DISTRIBUTING state even though this link will not
>       pass traffic on the local side
>
>    2. a slave goes into COLLECTING_DISTRIBUTING state without checking
>       if the aggregator is actually active
>
>    3. when in COLLECTING_DISTRIBUTING state, the partner parameters may
>       change, e.g. the partner_oper_port_state.SYNCHRONIZATION. The
>       local mux machine is not reacting to the change and continue to
>       keep the slave and bond up
>
>    4. When bond slave leaves an inactive aggregator and joins an active
>       aggregator, the actor oper port state need to update to SYNC state.

	This is a lot of subtle changes for one patch, and it's
difficult to read the patch and figure out which of the above points
corresponds to which code change(s).  I think this would have been
better as 2 or 3 patches, perhaps without the first blocks that merely
add debug statements.

	In general, though, I believe I understand the problems and the
solutions, and the solutions appear sound.

	For point 1, what it's doing is introducing an "ATTACHED-ish"
state, ultimately because the standard lacks the concept of "active" or
"inactive" aggregator.  From my reading, when the port transitions to
ATTACHED state, 5.4.15 "Mux machine" requires that it set SYNC at that
time.

	I understand why we would want to not enable SYNC for a port
that's a member of an aggregator that will not currently send or receive
traffic (is inactive in bonding-speak), but in my opinion we are
violating the standard and really should note that fact, and why we're
doing so, in the code.

	Point 2 is similar to point 1 (although here we're not
transitioning from ATTACHED to COLLECTING / COLLECTING_DISTRIBUTING
when the partner's SYNC is true); same comment applies.

	Points 3 and 4 look to be independent issues from points 1 and
2, and could be simple independent patches.

	-J

>v2:
> * fix style issues in bond_3ad.c
>
>Cc: Andy Gospodarek <[email-masked]>
>Reviewed-by: Nikolay Aleksandrov <[email-masked]>
>Signed-off-by: Wilson Kok <[email-masked]>
>Signed-off-by: Jonathan Toppins <[email-masked]>
>---
> drivers/net/bonding/bond_3ad.c |   44 +++++++++++++++++++++++++++++++---------
> 1 file changed, 34 insertions(+), 10 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
>index 8baa87d..e3c96b2 100644
>--- a/drivers/net/bonding/bond_3ad.c
>+++ b/drivers/net/bonding/bond_3ad.c
>@@ -467,11 +467,14 @@ static void __record_pdu(struct lacpdu *lacpdu, struct port *port)
> 		/* set the partner sync. to on if the partner is sync,
> 		 * and the port is matched
> 		 */
>-		if ((port->sm_vars & AD_PORT_MATCHED)
>-		    && (lacpdu->actor_state & AD_STATE_SYNCHRONIZATION))
>+		if ((port->sm_vars & AD_PORT_MATCHED) &&
>+		    (lacpdu->actor_state & AD_STATE_SYNCHRONIZATION)) {
> 			partner->port_state |= AD_STATE_SYNCHRONIZATION;
>-		else
>+			pr_debug("%s partner sync=1\n", port->slave->dev->name);
>+		} else {
> 			partner->port_state &= ~AD_STATE_SYNCHRONIZATION;
>+			pr_debug("%s partner sync=0\n", port->slave->dev->name);
>+		}
> 	}
> }
> 
>@@ -726,6 +729,8 @@ static inline void __update_lacpdu_from_port(struct port *port)
> 	lacpdu->actor_port_priority = htons(port->actor_port_priority);
> 	lacpdu->actor_port = htons(port->actor_port_number);
> 	lacpdu->actor_state = port->actor_oper_port_state;
>+	pr_debug("update lacpdu: %s, actor port state %x\n",
>+		 port->slave->dev->name, port->actor_oper_port_state);
> 
> 	/* lacpdu->reserved_3_1              initialized
> 	 * lacpdu->tlv_type_partner_info     initialized
>@@ -898,7 +903,9 @@ static void ad_mux_machine(struct port *port, bool *update_slave_arr)
> 			if ((port->sm_vars & AD_PORT_SELECTED) &&
> 			    (port->partner_oper.port_state & AD_STATE_SYNCHRONIZATION) &&
> 			    !__check_agg_selection_timer(port)) {
>-				port->sm_mux_state = AD_MUX_COLLECTING_DISTRIBUTING;
>+				if (port->aggregator->is_active)
>+					port->sm_mux_state =
>+					    AD_MUX_COLLECTING_DISTRIBUTING;
> 			} else if (!(port->sm_vars & AD_PORT_SELECTED) ||
> 				   (port->sm_vars & AD_PORT_STANDBY)) {
> 				/* if UNSELECTED or STANDBY */
>@@ -910,12 +917,16 @@ static void ad_mux_machine(struct port *port, bool *update_slave_arr)
> 				 */
> 				__set_agg_ports_ready(port->aggregator, __agg_ports_are_ready(port->aggregator));
> 				port->sm_mux_state = AD_MUX_DETACHED;
>+			} else if (port->aggregator->is_active) {
>+				port->actor_oper_port_state |=
>+				    AD_STATE_SYNCHRONIZATION;
> 			}
> 			break;
> 		case AD_MUX_COLLECTING_DISTRIBUTING:
> 			if (!(port->sm_vars & AD_PORT_SELECTED) ||
> 			    (port->sm_vars & AD_PORT_STANDBY) ||
>-			    !(port->partner_oper.port_state & AD_STATE_SYNCHRONIZATION)) {
>+			    !(port->partner_oper.port_state & AD_STATE_SYNCHRONIZATION) ||
>+			    !(port->actor_oper_port_state & AD_STATE_SYNCHRONIZATION)) {
> 				port->sm_mux_state = AD_MUX_ATTACHED;
> 			} else {
> 				/* if port state hasn't changed make
>@@ -937,8 +948,10 @@ static void ad_mux_machine(struct port *port, bool *update_slave_arr)
> 
> 	/* check if the state machine was changed */
> 	if (port->sm_mux_state != last_state) {
>-		pr_debug("Mux Machine: Port=%d, Last State=%d, Curr State=%d\n",
>-			 port->actor_port_number, last_state,
>+		pr_debug("Mux Machine: Port=%d (%s), Last State=%d, Curr State=%d\n",
>+			 port->actor_port_number,
>+			 port->slave->dev->name,
>+			 last_state,
> 			 port->sm_mux_state);
> 		switch (port->sm_mux_state) {
> 		case AD_MUX_DETACHED:
>@@ -953,7 +966,12 @@ static void ad_mux_machine(struct port *port, bool *update_slave_arr)
> 			port->sm_mux_timer_counter = __ad_timer_to_ticks(AD_WAIT_WHILE_TIMER, 0);
> 			break;
> 		case AD_MUX_ATTACHED:
>-			port->actor_oper_port_state |= AD_STATE_SYNCHRONIZATION;
>+			if (port->aggregator->is_active)
>+				port->actor_oper_port_state |=
>+				    AD_STATE_SYNCHRONIZATION;
>+			else
>+				port->actor_oper_port_state &=
>+				    ~AD_STATE_SYNCHRONIZATION;
> 			port->actor_oper_port_state &= ~AD_STATE_COLLECTING;
> 			port->actor_oper_port_state &= ~AD_STATE_DISTRIBUTING;
> 			ad_disable_collecting_distributing(port,
>@@ -963,6 +981,7 @@ static void ad_mux_machine(struct port *port, bool *update_slave_arr)
> 		case AD_MUX_COLLECTING_DISTRIBUTING:
> 			port->actor_oper_port_state |= AD_STATE_COLLECTING;
> 			port->actor_oper_port_state |= AD_STATE_DISTRIBUTING;
>+			port->actor_oper_port_state |= AD_STATE_SYNCHRONIZATION;
> 			ad_enable_collecting_distributing(port,
> 							  update_slave_arr);
> 			port->ntt = true;
>@@ -1044,8 +1063,10 @@ static void ad_rx_machine(struct lacpdu *lacpdu, struct port *port)
> 
> 	/* check if the State machine was changed or new lacpdu arrived */
> 	if ((port->sm_rx_state != last_state) || (lacpdu)) {
>-		pr_debug("Rx Machine: Port=%d, Last State=%d, Curr State=%d\n",
>-			 port->actor_port_number, last_state,
>+		pr_debug("Rx Machine: Port=%d (%s), Last State=%d, Curr State=%d\n",
>+			 port->actor_port_number,
>+			 port->slave->dev->name,
>+			 last_state,
> 			 port->sm_rx_state);
> 		switch (port->sm_rx_state) {
> 		case AD_RX_INITIALIZE:
>@@ -1394,6 +1415,9 @@ static void ad_port_selection_logic(struct port *port, bool *update_slave_arr)
> 
> 	aggregator = __get_first_agg(port);
> 	ad_agg_selection_logic(aggregator, update_slave_arr);
>+
>+	if (!port->aggregator->is_active)
>+		port->actor_oper_port_state &= ~AD_STATE_SYNCHRONIZATION;
> }
> 
> /* Decide if "agg" is a better choice for the new active aggregator that
>-- 
>1.7.10.4
>

---
	-Jay Vosburgh, [email-masked]