gprs_ns2: add gprs_ns2_nse_nsei() to get the nsei of a nse

Change-Id: I5f67e6a9bf4cb322bd169061fee0a528012ed54d
diff --git a/include/osmocom/gprs/gprs_ns2.h b/include/osmocom/gprs/gprs_ns2.h
index cbd6647..d798ac4 100644
--- a/include/osmocom/gprs/gprs_ns2.h
+++ b/include/osmocom/gprs/gprs_ns2.h
@@ -99,6 +99,7 @@
 
 struct gprs_ns2_nse *gprs_ns2_nse_by_nsei(struct gprs_ns2_inst *nsi, uint16_t nsei);
 struct gprs_ns2_nse *gprs_ns2_create_nse(struct gprs_ns2_inst *nsi, uint16_t nsei);
+uint16_t gprs_ns2_nse_nsei(struct gprs_ns2_nse *nse);
 void gprs_ns2_free_nse(struct gprs_ns2_nse *nse);
 
 /* create vc */
diff --git a/src/gb/gprs_ns2.c b/src/gb/gprs_ns2.c
index 334989c..58304cd 100644
--- a/src/gb/gprs_ns2.c
+++ b/src/gb/gprs_ns2.c
@@ -568,6 +568,15 @@
 	return nse;
 }
 
+/*! Return the NSEI
+ * \param[in] nse NS Entity
+ * \return the nsei.
+ */
+uint16_t gprs_ns2_nse_nsei(struct gprs_ns2_nse *nse)
+{
+	return nse->nsei;
+}
+
 /*! Destroy given NS Entity.
  *  \param[in] nse NS Entity to destroy */
 void gprs_ns2_free_nse(struct gprs_ns2_nse *nse)
diff --git a/src/gb/libosmogb.map b/src/gb/libosmogb.map
index 980b317..3d1d5d6 100644
--- a/src/gb/libosmogb.map
+++ b/src/gb/libosmogb.map
@@ -98,6 +98,7 @@
 gprs_ns2_ll_str_buf;
 gprs_ns2_ll_str_c;
 gprs_ns2_nse_by_nsei;
+gprs_ns2_nse_nsei;
 gprs_ns2_nsvc_by_nsvci;
 gprs_ns2_nsvc_by_sockaddr;
 gprs_ns2_recv_prim;