tipc: add sock dump to new netlink api

Add TIPC_NL_SOCK_GET command to the new tipc netlink API.

This command supports dumping of all available sockets with their
associated connection or publication(s). It could be extended to reply
with a single socket if the NLM_F_DUMP isn't set.

The information about a socket includes reference, address, connection
information / publication information.

Netlink logical layout of response message:
-> socket
    -> reference
    -> address
    [
    -> connection
        -> node
        -> socket
        [
        -> connected flag
        -> type
        -> instance
        ]
    ]
    [
    -> publication flag
    ]

Signed-off-by: Richard Alpe <richard.alpe@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/socket.h b/net/tipc/socket.h
index baa43d0..16dfd62 100644
--- a/net/tipc/socket.h
+++ b/net/tipc/socket.h
@@ -36,6 +36,7 @@
 #define _TIPC_SOCK_H
 
 #include <net/sock.h>
+#include <net/genetlink.h>
 
 #define TIPC_CONNACK_INTV         256
 #define TIPC_FLOWCTRL_WIN        (TIPC_CONNACK_INTV * 2)
@@ -47,5 +48,6 @@
 void tipc_sk_reinit(void);
 int tipc_sk_ref_table_init(u32 requested_size, u32 start);
 void tipc_sk_ref_table_stop(void);
+int tipc_nl_sk_dump(struct sk_buff *skb, struct netlink_callback *cb);
 
 #endif