tipc: improve groupcast scope handling

When a member joins a group, it also indicates a binding scope. This
makes it possible to create both node local groups, invisible to other
nodes, as well as cluster global groups, visible everywhere.

In order to avoid that different members end up having permanently
differing views of group size and memberhip, we must inhibit locally
and globally bound members from joining the same group.

We do this by using the binding scope as an additional separator between
groups. I.e., a member must ignore all membership events from sockets
using a different scope than itself, and all lookups for message
destinations must require an exact match between the message's lookup
scope and the potential target's binding scope.

Apart from making it possible to create local groups using the same
identity on different nodes, a side effect of this is that it now also
becomes possible to create a cluster global group with the same identity
across the same nodes, without interfering with the local groups.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 4 deletions

diff --git a/include/uapi/linux/tipc.h b/include/uapi/linux/tipc.h
index 35f79d1f8c3a..14bacc7e6cef 100644
--- a/include/uapi/linux/tipc.h
+++ b/include/uapi/linux/tipc.h
@@ -117,10 +117,9 @@ static inline unsigned int tipc_node(__u32 addr)
 /*
  * Publication scopes when binding port names and port name sequences
  */
-
-#define TIPC_ZONE_SCOPE		1
-#define TIPC_CLUSTER_SCOPE	2
-#define TIPC_NODE_SCOPE		3
+#define TIPC_ZONE_SCOPE         1
+#define TIPC_CLUSTER_SCOPE      2
+#define TIPC_NODE_SCOPE         3
 
 /*
  * Limiting values for messages