tipc: make subscriber server support net namespace

TIPC establishes one subscriber server which allows users to subscribe
their interesting name service status. After tipc supports namespace,
one dedicated tipc stack instance is created for each namespace, and
each instance can be deemed as one independent TIPC node. As a result,
subscriber server must be built for each namespace.

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

net/tipc/server.h

@@ -47,6 +47,7 @@
  * @conn_idr: identifier set of connection
  * @idr_lock: protect the connection identifier set
  * @idr_in_use: amount of allocated identifier entry
+ * @net: network namspace instance
  * @rcvbuf_cache: memory cache of server receive buffer
  * @rcv_wq: receive workqueue
  * @send_wq: send workqueue
@@ -63,6 +64,7 @@ struct tipc_server {
 	struct idr conn_idr;
 	spinlock_t idr_lock;
 	int idr_in_use;
+	struct net *net;
 	struct kmem_cache *rcvbuf_cache;
 	struct workqueue_struct *rcv_wq;
 	struct workqueue_struct *send_wq;
@@ -73,7 +75,7 @@ struct tipc_server {
 				  struct sockaddr_tipc *addr, void *usr_data,
 				  void *buf, size_t len);
 	struct sockaddr_tipc *saddr;
-	const char name[TIPC_SERVER_NAME_LEN];
+	char name[TIPC_SERVER_NAME_LEN];
 	int imp;
 	int type;
 };