tipc: simplify bearer level broadcast

Until now, we have been keeping track of the exact set of broadcast
destinations though the help structure tipc_node_map. This leads us to
have to maintain a whole infrastructure for supporting this, including
a pseudo-bearer and a number of functions to manipulate both the bearers
and the node map correctly. Apart from the complexity, this approach is
also limiting, as struct tipc_node_map only can support cluster local
broadcast if we want to avoid it becoming excessively large. We want to
eliminate this limitation, in order to enable introduction of scoped
multicast in the future.

A closer analysis reveals that it is unnecessary maintaining this "full
set" overview; it is sufficient to keep a counter per bearer, indicating
how many nodes can be reached via this bearer at the moment. The protocol
is now robust enough to handle transitional discrepancies between the
nominal number of reachable destinations, as expected by the broadcast
protocol itself, and the number which is actually reachable at the
moment. The initial broadcast synchronization, in conjunction with the
retransmission mechanism, ensures that all packets will eventually be
acknowledged by the correct set of destinations.

This commit introduces these changes.

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

1 files changed, 3 insertions, 0 deletions

diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 6426f242f626..9fc1e074f7c0 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -163,6 +163,7 @@ struct tipc_bearer {
 	u32 identity;
 	struct tipc_link_req *link_req;
 	char net_plane;
+	int node_cnt;
 	struct tipc_node_map nodes;
 };
 
@@ -220,5 +221,7 @@ void tipc_bearer_send(struct net *net, u32 bearer_id, struct sk_buff *buf,
 void tipc_bearer_xmit(struct net *net, u32 bearer_id,
 		      struct sk_buff_head *xmitq,
 		      struct tipc_media_addr *dst);
+void tipc_bearer_bc_xmit(struct net *net, u32 bearer_id,
+			 struct sk_buff_head *xmitq);
 
 #endif	/* _TIPC_BEARER_H */