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, 7 insertions, 3 deletions

diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c
index 1052341..44df528 100644
--- a/net/tipc/subscr.c
+++ b/net/tipc/subscr.c
@@ -118,15 +118,19 @@ void tipc_subscrp_convert_seq(struct tipc_name_seq *in, int swap,
 
 void tipc_subscrp_report_overlap(struct tipc_subscription *sub, u32 found_lower,
 				 u32 found_upper, u32 event, u32 port_ref,
-				 u32 node, int must)
+				 u32 node, u32 scope, int must)
 {
+	u32 filter = htohl(sub->evt.s.filter, sub->swap);
 	struct tipc_name_seq seq;
 
 	tipc_subscrp_convert_seq(&sub->evt.s.seq, sub->swap, &seq);
 	if (!tipc_subscrp_check_overlap(&seq, found_lower, found_upper))
 		return;
-	if (!must &&
-	    !(htohl(sub->evt.s.filter, sub->swap) & TIPC_SUB_PORTS))
+	if (!must && !(filter & TIPC_SUB_PORTS))
+		return;
+	if (filter & TIPC_SUB_CLUSTER_SCOPE && scope == TIPC_NODE_SCOPE)
+		return;
+	if (filter & TIPC_SUB_NODE_SCOPE && scope != TIPC_NODE_SCOPE)
 		return;
 
 	tipc_subscrp_send_event(sub, found_lower, found_upper, event, port_ref,