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>

drivers/net/bonding/bond_3ad.c

@@ -38,6 +38,7 @@
 #define AD_STANDBY                 0x2
 #define AD_MAX_TX_IN_SECOND        3
 #define AD_COLLECTOR_MAX_DELAY     0
+#define AD_MONITOR_CHURNED         0x1000
 
 /* Timer definitions (43.4.4 in the 802.3ad standard) */
 #define AD_FAST_PERIODIC_TIME      1
@@ -1013,16 +1014,19 @@ static void ad_rx_machine(struct lacpdu *lacpdu, struct port *port)
 	/* check if state machine should change state */
 
 	/* first, check if port was reinitialized */
-	if (port->sm_vars & AD_PORT_BEGIN)
+	if (port->sm_vars & AD_PORT_BEGIN) {
 		port->sm_rx_state = AD_RX_INITIALIZE;
+		port->sm_vars |= AD_MONITOR_CHURNED;
 	/* check if port is not enabled */
-	else if (!(port->sm_vars & AD_PORT_BEGIN)
+	} else if (!(port->sm_vars & AD_PORT_BEGIN)
 		 && !port->is_enabled && !(port->sm_vars & AD_PORT_MOVED))
 		port->sm_rx_state = AD_RX_PORT_DISABLED;
 	/* check if new lacpdu arrived */
 	else if (lacpdu && ((port->sm_rx_state == AD_RX_EXPIRED) ||
 		 (port->sm_rx_state == AD_RX_DEFAULTED) ||
 		 (port->sm_rx_state == AD_RX_CURRENT))) {
+		if (port->sm_rx_state != AD_RX_CURRENT)
+			port->sm_vars |= AD_MONITOR_CHURNED;
 		port->sm_rx_timer_counter = 0;
 		port->sm_rx_state = AD_RX_CURRENT;
 	} else {
@@ -1100,9 +1104,11 @@ static void ad_rx_machine(struct lacpdu *lacpdu, struct port *port)
 			 */
 			port->partner_oper.port_state &= ~AD_STATE_SYNCHRONIZATION;
 			port->sm_vars &= ~AD_PORT_MATCHED;
+			port->partner_oper.port_state |= AD_STATE_LACP_TIMEOUT;
 			port->partner_oper.port_state |= AD_STATE_LACP_ACTIVITY;
 			port->sm_rx_timer_counter = __ad_timer_to_ticks(AD_CURRENT_WHILE_TIMER, (u16)(AD_SHORT_TIMEOUT));
 			port->actor_oper_port_state |= AD_STATE_EXPIRED;
+			port->sm_vars |= AD_MONITOR_CHURNED;
 			break;
 		case AD_RX_DEFAULTED:
 			__update_default_selected(port);
@@ -1131,6 +1137,45 @@ static void ad_rx_machine(struct lacpdu *lacpdu, struct port *port)
 	}
 }
 
+/**
+ * ad_churn_machine - handle port churn's state machine
+ * @port: the port we're looking at
+ *
+ */
+static void ad_churn_machine(struct port *port)
+{
+	if (port->sm_vars & AD_MONITOR_CHURNED) {
+		port->sm_vars &= ~AD_MONITOR_CHURNED;
+		port->sm_churn_actor_state = AD_CHURN_MONITOR;
+		port->sm_churn_partner_state = AD_CHURN_MONITOR;
+		port->sm_churn_actor_timer_counter =
+			__ad_timer_to_ticks(AD_ACTOR_CHURN_TIMER, 0);
+		 port->sm_churn_partner_timer_counter =
+			 __ad_timer_to_ticks(AD_PARTNER_CHURN_TIMER, 0);
+		return;
+	}
+	if (port->sm_churn_actor_timer_counter &&
+	    !(--port->sm_churn_actor_timer_counter) &&
+	    port->sm_churn_actor_state == AD_CHURN_MONITOR) {
+		if (port->actor_oper_port_state & AD_STATE_SYNCHRONIZATION) {
+			port->sm_churn_actor_state = AD_NO_CHURN;
+		} else {
+			port->churn_actor_count++;
+			port->sm_churn_actor_state = AD_CHURN;
+		}
+	}
+	if (port->sm_churn_partner_timer_counter &&
+	    !(--port->sm_churn_partner_timer_counter) &&
+	    port->sm_churn_partner_state == AD_CHURN_MONITOR) {
+		if (port->partner_oper.port_state & AD_STATE_SYNCHRONIZATION) {
+			port->sm_churn_partner_state = AD_NO_CHURN;
+		} else {
+			port->churn_partner_count++;
+			port->sm_churn_partner_state = AD_CHURN;
+		}
+	}
+}
+
 /**
  * ad_tx_machine - handle a port's tx state machine
  * @port: the port we're looking at
@@ -1745,6 +1790,13 @@ static void ad_initialize_port(struct port *port, int lacp_fast)
 		port->next_port_in_aggregator = NULL;
 		port->transaction_id = 0;
 
+		port->sm_churn_actor_timer_counter = 0;
+		port->sm_churn_actor_state = 0;
+		port->churn_actor_count = 0;
+		port->sm_churn_partner_timer_counter = 0;
+		port->sm_churn_partner_state = 0;
+		port->churn_partner_count = 0;
+
 		memcpy(&port->lacpdu, &lacpdu, sizeof(lacpdu));
 	}
 }
@@ -2164,6 +2216,7 @@ void bond_3ad_state_machine_handler(struct work_struct *work)
 		ad_port_selection_logic(port, &update_slave_arr);
 		ad_mux_machine(port, &update_slave_arr);
 		ad_tx_machine(port);
+		ad_churn_machine(port);
 
 		/* turn off the BEGIN bit, since we already handled it */
 		if (port->sm_vars & AD_PORT_BEGIN)

drivers/net/bonding/bond_procfs.c

@@ -176,18 +176,51 @@ static void bond_info_show_slave(struct seq_file *seq,
 		   slave->link_failure_count);
 
 	seq_printf(seq, "Permanent HW addr: %pM\n", slave->perm_hwaddr);
+	seq_printf(seq, "Slave queue ID: %d\n", slave->queue_id);
 
 	if (BOND_MODE(bond) == BOND_MODE_8023AD) {
-		const struct aggregator *agg
-			= SLAVE_AD_INFO(slave)->port.aggregator;
+		const struct port *port = &SLAVE_AD_INFO(slave)->port;
+		const struct aggregator *agg = port->aggregator;
 
-		if (agg)
+		if (agg) {
 			seq_printf(seq, "Aggregator ID: %d\n",
 				   agg->aggregator_identifier);
-		else
+			seq_printf(seq, "Actor Churn State: %s\n",
+				   bond_3ad_churn_desc(port->sm_churn_actor_state));
+			seq_printf(seq, "Partner Churn State: %s\n",
+				   bond_3ad_churn_desc(port->sm_churn_partner_state));
+			seq_printf(seq, "Actor Churned Count: %d\n",
+				   port->churn_actor_count);
+			seq_printf(seq, "Partner Churned Count: %d\n",
+				   port->churn_partner_count);
+
+			seq_puts(seq, "details actor lacp pdu:\n");
+			seq_printf(seq, "    system priority: %d\n",
+				   port->actor_system_priority);
+			seq_printf(seq, "    port key: %d\n",
+				   port->actor_oper_port_key);
+			seq_printf(seq, "    port priority: %d\n",
+				   port->actor_port_priority);
+			seq_printf(seq, "    port number: %d\n",
+				   port->actor_port_number);
+			seq_printf(seq, "    port state: %d\n",
+				   port->actor_oper_port_state);
+
+			seq_puts(seq, "details partner lacp pdu:\n");
+			seq_printf(seq, "    system priority: %d\n",
+				   port->partner_oper.system_priority);
+			seq_printf(seq, "    oper key: %d\n",
+				   port->partner_oper.key);
+			seq_printf(seq, "    port priority: %d\n",
+				   port->partner_oper.port_priority);
+			seq_printf(seq, "    port number: %d\n",
+				   port->partner_oper.port_number);
+			seq_printf(seq, "    port state: %d\n",
+				   port->partner_oper.port_state);
+		} else {
 			seq_puts(seq, "Aggregator ID: N/A\n");
+		}
 	}
-	seq_printf(seq, "Slave queue ID: %d\n", slave->queue_id);
 }
 
 static int bond_info_seq_show(struct seq_file *seq, void *v)

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);