net: hsr: add support for EntryForgetTime

In IEC 62439-3 EntryForgetTime is defined with a value of 400 ms. When a
node does not send any frame within this time, the sequence number check
for can be ignored. This solves communication issues with Cisco IE 2000
in Redbox mode.

Fixes: f421436a ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: Marco Wenzel <marco.wenzel@a-eberle.de>
Reviewed-by: George McCollister <george.mccollister@gmail.com>
Tested-by: George McCollister <george.mccollister@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210224094653.1440-1-marco.wenzel@a-eberle.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/hsr/hsr_framereg.c

@@ -164,8 +164,10 @@ static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
 	 * as initialization. (0 could trigger an spurious ring error warning).
 	 */
 	now = jiffies;
-	for (i = 0; i < HSR_PT_PORTS; i++)
+	for (i = 0; i < HSR_PT_PORTS; i++) {
 		new_node->time_in[i] = now;
+		new_node->time_out[i] = now;
+	}
 	for (i = 0; i < HSR_PT_PORTS; i++)
 		new_node->seq_out[i] = seq_out;
 
@@ -413,9 +415,12 @@ void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port,
 int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
 			   u16 sequence_nr)
 {
-	if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]))
+	if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]) &&
+	    time_is_after_jiffies(node->time_out[port->type] +
+	    msecs_to_jiffies(HSR_ENTRY_FORGET_TIME)))
 		return 1;
 
+	node->time_out[port->type] = jiffies;
 	node->seq_out[port->type] = sequence_nr;
 	return 0;
 }

net/hsr/hsr_framereg.h

@@ -75,6 +75,7 @@ struct hsr_node {
 	enum hsr_port_type	addr_B_port;
 	unsigned long		time_in[HSR_PT_PORTS];
 	bool			time_in_stale[HSR_PT_PORTS];
+	unsigned long		time_out[HSR_PT_PORTS];
 	/* if the node is a SAN */
 	bool			san_a;
 	bool			san_b;

net/hsr/hsr_main.h

@@ -22,6 +22,7 @@
 #define HSR_LIFE_CHECK_INTERVAL		 2000 /* ms */
 #define HSR_NODE_FORGET_TIME		60000 /* ms */
 #define HSR_ANNOUNCE_INTERVAL		  100 /* ms */
+#define HSR_ENTRY_FORGET_TIME		  400 /* ms */
 
 /* By how much may slave1 and slave2 timestamps of latest received frame from
  * each node differ before we notify of communication problem?