tipc: support in-order name publication events

It is observed that TIPC service binding order will not be kept in the
publication event report to user if the service is subscribed after the
bindings.

For example, services are bound by application in the following order:

Server: bound port A to {18888,66,66} scope 2
Server: bound port A to {18888,33,33} scope 2

Now, if a client subscribes to the service range (e.g. {18888, 0-100}),
it will get the 'TIPC_PUBLISHED' events in that binding order only when
the subscription is started before the bindings.
Otherwise, if started after the bindings, the events will arrive in the
opposite order:

Client: received event for published {18888,33,33}
Client: received event for published {18888,66,66}

For the latter case, it is clear that the bindings have existed in the
name table already, so when reported, the events' order will follow the
order of the rbtree binding nodes (- a node with lesser 'lower'/'upper'
range value will be first).

This is correct as we provide the tracking on a specific service status
(available or not), not the relationship between multiple services.
However, some users expect to see the same order of arriving events
irrespective of when the subscription is issued. This turns out to be
easy to fix. We now add functionality to ensure that publication events
always are issued in the same temporal order as the corresponding
bindings were performed.

v2: replace the unnecessary macro - 'publication_after()' with inline
function.
v3: reuse 'time_after32()' instead of reinventing the same exact code.

Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/net/tipc/name_table.h b/net/tipc/name_table.h
index f79066334cc8..728bc7016c38 100644
--- a/net/tipc/name_table.h
+++ b/net/tipc/name_table.h
@@ -58,6 +58,7 @@ struct tipc_group;
  * @node: network address of publishing socket's node
  * @port: publishing port
  * @key: publication key, unique across the cluster
+ * @id: publication id
  * @binding_node: all publications from the same node which bound this one
  * - Remote publications: in node->publ_list
  *   Used by node/name distr to withdraw publications when node is lost
@@ -69,6 +70,7 @@ struct tipc_group;
  *   Used by closest_first and multicast receive lookup algorithms
  * @all_publ: all publications identical to this one, whatever node and scope
  *   Used by round-robin lookup algorithm
+ * @list: to form a list of publications in temporal order
  * @rcu: RCU callback head used for deferred freeing
  */
 struct publication {
@@ -79,10 +81,12 @@ struct publication {
 	u32 node;
 	u32 port;
 	u32 key;
+	u32 id;
 	struct list_head binding_node;
 	struct list_head binding_sock;
 	struct list_head local_publ;
 	struct list_head all_publ;
+	struct list_head list;
 	struct rcu_head rcu;
 };