tipc: introduce message evaluation function

When a message arrives in a node and finds no destination
socket, we may need to drop it, reject it, or forward it after
a secondary destination lookup. The latter two cases currently
results in a code path that is perceived as complex, because it
follows a deep call chain via obscure functions such as
net_route_named_msg() and net_route_msg().

We now introduce a function, tipc_msg_eval(), that takes the
decision about whether such a message should be rejected or
forwarded, but leaves it to the caller to actually perform
the indicated action.

If the decision is 'reject', it is still the task of the recently
introduced function tipc_msg_reverse() to take the final decision
about whether the message is rejectable or not. In the latter case
it drops the message.

As a result of this change, we can finally eliminate the function
net_route_named_msg(), and hence become independent of net_route_msg().

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

1 files changed, 6 insertions, 27 deletions

diff --git a/net/tipc/net.c b/net/tipc/net.c
index f64375e7f99f..5f7d6ffb5465 100644
--- a/net/tipc/net.c
+++ b/net/tipc/net.c
@@ -1,7 +1,7 @@
 /*
  * net/tipc/net.c: TIPC network routing code
  *
- * Copyright (c) 1995-2006, Ericsson AB
+ * Copyright (c) 1995-2006, 2014, Ericsson AB
  * Copyright (c) 2005, 2010-2011, Wind River Systems
  * All rights reserved.
  *
@@ -103,29 +103,6 @@
  *       This is always used within the scope of a tipc_nametbl_lock(read).
  *     - A local spin_lock protecting the queue of subscriber events.
 */
-
-static void net_route_named_msg(struct sk_buff *buf)
-{
-	struct tipc_msg *msg = buf_msg(buf);
-	u32 dnode;
-	u32 dport;
-
-	if (!msg_named(msg)) {
-		kfree_skb(buf);
-		return;
-	}
-
-	dnode = addr_domain(msg_lookup_scope(msg));
-	dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode);
-	if (dport) {
-		msg_set_destnode(msg, dnode);
-		msg_set_destport(msg, dport);
-		tipc_net_route_msg(buf);
-		return;
-	}
-	tipc_reject_msg(buf, TIPC_ERR_NO_NAME);
-}
-
 void tipc_net_route_msg(struct sk_buff *buf)
 {
 	struct tipc_msg *msg;
@@ -141,10 +118,12 @@ void tipc_net_route_msg(struct sk_buff *buf)
 		if (msg_isdata(msg)) {
 			if (msg_mcast(msg))
 				tipc_port_mcast_rcv(buf, NULL);
-			else if (msg_destport(msg))
+			else if (msg_destport(msg)) {
 				tipc_sk_rcv(buf);
-			else
-				net_route_named_msg(buf);
+			} else {
+				pr_warn("Cannot route msg; no destination\n");
+				kfree_skb(buf);
+			}
 			return;
 		}
 		switch (msg_user(msg)) {