tipc: simplify endianness handling in topology subscriber

Because of the requirement for total distribution transparency, users
send subscriptions and receive topology events in their own host format.
It is up to the topology server to determine this format and do the
correct conversions to and from its own host format when needed.

Until now, this has been handled in a rather non-transparent way inside
the topology server and subscriber code, leading to unnecessary
complexity when creating subscriptions and issuing events.

We now improve this situation by adding two new macros, tipc_sub_read()
and tipc_evt_write(). Both those functions calculate the need for
conversion internally before performing their respective operations.
Hence, all handling of such conversions become transparent to the rest
of the code.

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

1 files changed, 27 insertions, 9 deletions

diff --git a/net/tipc/subscr.h b/net/tipc/subscr.h
index 64ffd32d15e6..db80e41bba08 100644
--- a/net/tipc/subscr.h
+++ b/net/tipc/subscr.h
@@ -52,7 +52,6 @@ struct tipc_conn;
  * @timer: timer governing subscription duration (optional)
  * @nameseq_list: adjacent subscriptions in name sequence's subscription list
  * @subscrp_list: adjacent subscriptions in subscriber's subscription list
- * @swap: indicates if subscriber uses opposite endianness in its messages
  * @evt: template for events generated by subscription
  */
 struct tipc_subscription {
@@ -63,28 +62,47 @@ struct tipc_subscription {
 	struct list_head subscrp_list;
 	struct tipc_event evt;
 	int conid;
-	bool swap;
 	bool inactive;
 	spinlock_t lock; /* serialize up/down and timer events */
 };
 
 struct tipc_subscription *tipc_subscrp_subscribe(struct tipc_server *srv,
 						 struct tipc_subscr *s,
-						 int conid, bool swap,
-						 bool status);
+						 int conid);
 void tipc_sub_delete(struct tipc_subscription *sub);
+
 int tipc_subscrp_check_overlap(struct tipc_name_seq *seq, u32 found_lower,
 			       u32 found_upper);
 void tipc_subscrp_report_overlap(struct tipc_subscription *sub,
-				 u32 found_lower, u32 found_upper, u32 event,
-				 u32 port_ref, u32 node, u32 scope, int must);
-void tipc_subscrp_convert_seq(struct tipc_name_seq *in, int swap,
-			      struct tipc_name_seq *out);
-u32 tipc_subscrp_convert_seq_type(u32 type, int swap);
+				 u32 found_lower, u32 found_upper,
+				 u32 event, u32 port, u32 node,
+				 u32 scope, int must);
 int tipc_topsrv_start(struct net *net);
 void tipc_topsrv_stop(struct net *net);
 
 void tipc_subscrp_put(struct tipc_subscription *subscription);
 void tipc_subscrp_get(struct tipc_subscription *subscription);
 
+#define TIPC_FILTER_MASK (TIPC_SUB_PORTS | TIPC_SUB_SERVICE | TIPC_SUB_CANCEL)
+
+/* tipc_sub_read - return field_ of struct sub_ in host endian format
+ */
+#define tipc_sub_read(sub_, field_)					\
+	({								\
+		struct tipc_subscr *sub__ = sub_;			\
+		u32 val__ = (sub__)->field_;				\
+		int swap_ = !((sub__)->filter & TIPC_FILTER_MASK);	\
+		(swap_ ? swab32(val__) : val__);			\
+	})
+
+/* tipc_evt_write - write val_ to field_ of struct evt_ in user endian format
+ */
+#define tipc_evt_write(evt_, field_, val_)				\
+	({								\
+		struct tipc_event *evt__ = evt_;			\
+		u32 val__ = val_;					\
+		int swap_ = !((evt__)->s.filter & (TIPC_FILTER_MASK));	\
+		(evt__)->field_ = swap_ ? swab32(val__) : val__;	\
+	})
+
 #endif