Introduce new header file sgsn/gtp.h

It will be used to store all stuff relatd to libgtp use and GTP
protocol, similar to what we already do for other protocols.

Change-Id: I4aae35cd0ea401856cd822cb507d668350d07a89

include/osmocom/sgsn/Makefile.am

@@ -21,6 +21,7 @@ noinst_HEADERS = \
 	gprs_sndcp_xid.h \
 	gprs_subscriber.h \
 	gprs_utils.h \
+	gtp.h \
 	gtphub.h \
 	gtp_ggsn.h \
 	gtp_mme.h \

include/osmocom/sgsn/gprs_sgsn.h

@@ -460,9 +460,6 @@ struct gsm_auth_tuple *sgsn_auth_get_tuple(struct sgsn_mm_ctx *mmctx,
 /* Called on subscriber data updates */
 void sgsn_update_subscriber_data(struct sgsn_mm_ctx *mmctx);
 
-struct sgsn_instance;
-int sgsn_gtp_init(struct sgsn_instance *sgi);
-
 void sgsn_rate_ctr_init();
 
 #endif /* _GPRS_SGSN_H */

include/osmocom/sgsn/gtp.h

@@ -0,0 +1,5 @@
+#pragma once
+
+struct sgsn_instance;
+
+int sgsn_gtp_init(struct sgsn_instance *sgi);

src/sgsn/sgsn_main.c

@@ -65,6 +65,7 @@
 #include <osmocom/sgsn/gprs_ns.h>
 #include <osmocom/sgsn/gprs_bssgp.h>
 #include <osmocom/sgsn/gprs_subscriber.h>
+#include <osmocom/sgsn/gtp.h>
 
 #include <osmocom/ctrl/control_if.h>
 #include <osmocom/ctrl/ports.h>