tipc: introduce new capability flag for cluster

As a preparation for introducing a smooth switching between replicast
and broadcast method for multicast message, We have to introduce a new
capability flag TIPC_MCAST_RBCTL to handle this new feature.

During a cluster upgrade a node can come back with this new capabilities
which also must be reflected in the cluster capabilities field.
The new feature is only applicable if all node in the cluster supports
this new capability.

Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/core.c

@@ -43,6 +43,7 @@
 #include "net.h"
 #include "socket.h"
 #include "bcast.h"
+#include "node.h"
 
 #include <linux/module.h>
 
@@ -59,6 +60,7 @@ static int __net_init tipc_init_net(struct net *net)
 	tn->node_addr = 0;
 	tn->trial_addr = 0;
 	tn->addr_trial_end = 0;
+	tn->capabilities = TIPC_NODE_CAPABILITIES;
 	memset(tn->node_id, 0, sizeof(tn->node_id));
 	memset(tn->node_id_string, 0, sizeof(tn->node_id_string));
 	tn->mon_threshold = TIPC_DEF_MON_THRESHOLD;

net/tipc/core.h

@@ -122,6 +122,9 @@ struct tipc_net {
 	/* Topology subscription server */
 	struct tipc_topsrv *topsrv;
 	atomic_t subscription_count;
+
+	/* Cluster capabilities */
+	u16 capabilities;
 };
 
 static inline struct tipc_net *tipc_net(struct net *net)

net/tipc/node.c

@@ -383,6 +383,11 @@ static struct tipc_node *tipc_node_create(struct net *net, u32 addr,
 				tipc_link_update_caps(l, capabilities);
 		}
 		write_unlock_bh(&n->lock);
+		/* Calculate cluster capabilities */
+		tn->capabilities = TIPC_NODE_CAPABILITIES;
+		list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
+			tn->capabilities &= temp_node->capabilities;
+		}
 		goto exit;
 	}
 	n = kzalloc(sizeof(*n), GFP_ATOMIC);
@@ -433,6 +438,11 @@ static struct tipc_node *tipc_node_create(struct net *net, u32 addr,
 			break;
 	}
 	list_add_tail_rcu(&n->list, &temp_node->list);
+	/* Calculate cluster capabilities */
+	tn->capabilities = TIPC_NODE_CAPABILITIES;
+	list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
+		tn->capabilities &= temp_node->capabilities;
+	}
 	trace_tipc_node_create(n, true, " ");
 exit:
 	spin_unlock_bh(&tn->node_list_lock);
@@ -589,6 +599,7 @@ static void  tipc_node_clear_links(struct tipc_node *node)
  */
 static bool tipc_node_cleanup(struct tipc_node *peer)
 {
+	struct tipc_node *temp_node;
 	struct tipc_net *tn = tipc_net(peer->net);
 	bool deleted = false;
 
@@ -604,6 +615,13 @@ static bool tipc_node_cleanup(struct tipc_node *peer)
 		deleted = true;
 	}
 	tipc_node_write_unlock(peer);
+
+	/* Calculate cluster capabilities */
+	tn->capabilities = TIPC_NODE_CAPABILITIES;
+	list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
+		tn->capabilities &= temp_node->capabilities;
+	}
+
 	spin_unlock_bh(&tn->node_list_lock);
 	return deleted;
 }

net/tipc/node.h

@@ -51,7 +51,8 @@ enum {
 	TIPC_BLOCK_FLOWCTL    = (1 << 3),
 	TIPC_BCAST_RCAST      = (1 << 4),
 	TIPC_NODE_ID128       = (1 << 5),
-	TIPC_LINK_PROTO_SEQNO = (1 << 6)
+	TIPC_LINK_PROTO_SEQNO = (1 << 6),
+	TIPC_MCAST_RBCTL      = (1 << 7)
 };
 
 #define TIPC_NODE_CAPABILITIES (TIPC_SYN_BIT           |  \
@@ -60,7 +61,8 @@ enum {
 				TIPC_BCAST_RCAST       |   \
 				TIPC_BLOCK_FLOWCTL     |   \
 				TIPC_NODE_ID128        |   \
-				TIPC_LINK_PROTO_SEQNO)
+				TIPC_LINK_PROTO_SEQNO  |   \
+				TIPC_MCAST_RBCTL)
 #define INVALID_BEARER_ID -1
 
 void tipc_node_stop(struct net *net);