bonding: Implement port churn-machine (AD standard 43.4.17).

The Churn Detection machines detect the situation where a port is operable,
but the Actor and Partner have not attached the link to an Aggregator and
brought the link into operation within a bound time period. Under normal
operation of the LACP, agreement between Actor and Partner should be reached
very rapidly. Continued failure to reach agreement can be symptomatic of
device failure.

Actor-churn-detection state-machine
Reviewed-by: Nikolay Aleksandrov <nikolay@redhat.com>

===================================

BEGIN=True + PortEnable=False
           |
           v
 +------------------------+   ActorPort.Sync=True  +------------------+
 |   ACTOR_CHURN_MONITOR  | ---------------------> |  NO_ACTOR_CHURN  |
 |========================|                        |==================|
 |    ActorChurn=False    |  ActorPort.Sync=False  | ActorChurn=False |
 | ActorChurn.Timer=Start | <--------------------- |                  |
 +------------------------+                        +------------------+
           |                                                ^
           |                                                |
  ActorChurn.Timer=Expired                                  |
           |                                       ActorPort.Sync=True
           |                                                |
           |                +-----------------+             |
           |                |   ACTOR_CHURN   |             |
           |                |=================|             |
           +--------------> | ActorChurn=True | ------------+
                            |                 |
                            +-----------------+

Similar for the Partner-churn-detection.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 29 insertions, 0 deletions

diff --git a/include/net/bond_3ad.h b/include/net/bond_3ad.h
index f04cdbb..c2a40a17 100644
--- a/include/net/bond_3ad.h
+++ b/include/net/bond_3ad.h
@@ -82,6 +82,13 @@ typedef enum {
 	AD_TRANSMIT		/* tx Machine */
 } tx_states_t;
 
+/* churn machine states(43.4.17 in the 802.3ad standard) */
+typedef enum {
+	 AD_CHURN_MONITOR, /* monitoring for churn */
+	 AD_CHURN,         /* churn detected (error) */
+	 AD_NO_CHURN       /* no churn (no error) */
+} churn_state_t;
+
 /* rx indication types */
 typedef enum {
 	AD_TYPE_LACPDU = 1,	/* type lacpdu */
@@ -229,6 +236,12 @@ typedef struct port {
 	u16 sm_mux_timer_counter;	/* state machine mux timer counter */
 	tx_states_t sm_tx_state;	/* state machine tx state */
 	u16 sm_tx_timer_counter;	/* state machine tx timer counter(allways on - enter to transmit state 3 time per second) */
+	u16 sm_churn_actor_timer_counter;
+	u16 sm_churn_partner_timer_counter;
+	u32 churn_actor_count;
+	u32 churn_partner_count;
+	churn_state_t sm_churn_actor_state;
+	churn_state_t sm_churn_partner_state;
 	struct slave *slave;		/* pointer to the bond slave that this port belongs to */
 	struct aggregator *aggregator;	/* pointer to an aggregator that this port related to */
 	struct port *next_port_in_aggregator;	/* Next port on the linked list of the parent aggregator */
@@ -262,6 +275,22 @@ struct ad_slave_info {
 	u16 id;
 };
 
+static inline const char *bond_3ad_churn_desc(churn_state_t state)
+{
+	static const char *const churn_description[] = {
+		"monitoring",
+		"churned",
+		"none",
+		"unknown"
+	};
+	int max_size = sizeof(churn_description) / sizeof(churn_description[0]);
+
+	if (state >= max_size)
+		state = max_size - 1;
+
+	return churn_description[state];
+}
+
 /* ========== AD Exported functions to the main bonding code ========== */
 void bond_3ad_initialize(struct bonding *bond, u16 tick_resolution);
 void bond_3ad_bind_slave(struct slave *slave);