mscsplit: getting grips on header scopes

1 files changed, 34 insertions, 7 deletions

diff --git a/openbsc/include/openbsc/msc_ifaces.h b/openbsc/include/openbsc/msc_ifaces.h
index dc2b9e1da..2dee3918a 100644
--- a/openbsc/include/openbsc/msc_ifaces.h
+++ b/openbsc/include/openbsc/msc_ifaces.h
@@ -9,28 +9,55 @@
  * 2G will use the A-interface,
  * 3G aka UMTS will use the Iu-interface (for the MSC, it's IuCS).
  *
- * Below callback structures allows linking parts of the MSC code without
+ * Below callback structures allow linking parts of the MSC code without
  * having to include entire infrastructures of external libraries. For example,
  * a unit test does not need to link against external ASN1 libraries if it is
  * never going to encode actual outgoing messages. It is up to each building
- * scope to plug real world functions or to have mere dummy implementations. */
+ * scope to plug real world functions or to have mere dummy implementations.
+ *
+ * For example, for msc_tx_foo(ifaces, conn, msg), depending on
+ * conn->via_iface, either ifaces->a.tx() or ifaces.iu_cs.tx() is called to
+ * dispatch the msg.
+ *
+ * To replace the default dummy implementations, a user would do the likes of:
+ *
+ *   int my_iu_cs_tx(...)
+ *   {
+ *           ...
+ *   }
+ *
+ *   int main(void)
+ *   {
+ *           global_msc_ifaces->network = my_network;
+ *           global_msc_ifaces->iu_cs.tx = my_iu_cs_tx;
+ *           ...
+ *   }
+ *
+ * (or use readily available implementations like iu_tx() from libiu)
+ */
+
+struct msc_ifaces {
 
-extern struct {
+	/* global gsm_network to lookup BSC|RNC connections etc. */
+	struct gsm_network *network;
 
 	struct {
 		/* libmsc calls this to send out messages to an A-interface */
 		int (*tx)(struct msgb *msg, uint8_t sapi);
+		/* TODO: I don't understand sapi yet, may not apply to A-iface */
 	} a;
 
 	struct {
 		/* libmsc calls this to send out messages to an Iu-interface */
 		int (*tx)(struct msgb *msg, uint8_t sapi);
+		/* TODO: I don't understand sapi yet */
 	} iu_cs;
 
-} msc_ifaces;
+};
+
+extern struct msc_ifaces *global_msc_ifaces;
 
 
+int msc_tx_dtap(struct gsm_subscriber_connection *conn,
+		struct msgb *msg);
 
-/* Depending on conn->via_iface (A or IuCS), submit msg to the proper link api. */
-extern int msc_submit_dtap(struct gsm_subscriber_connection *conn,
-			   struct msgb *msg);