gprs_ns2: add gprs_ns2_nse_sns_remote() returns the initial SNS address

Allows the PCU to get the SNS remote address.

Change-Id: I54f110acc3acccb362f6e554324d08cc42b7c328

include/osmocom/gprs/gprs_ns2.h

@@ -138,6 +138,7 @@ void gprs_ns2_free_binds(struct gprs_ns2_inst *nsi);
 int gprs_ns2_ip_connect_sns(struct gprs_ns2_vc_bind *bind,
 			    const struct osmo_sockaddr *remote,
 			    uint16_t nsei);
+const struct osmo_sockaddr *gprs_ns2_nse_sns_remote(struct gprs_ns2_nse *nse);
 
 const struct osmo_sockaddr *gprs_ns2_ip_vc_remote(struct gprs_ns2_vc *nsvc);
 const struct osmo_sockaddr *gprs_ns2_ip_vc_local(const struct gprs_ns2_vc *nsvc);

src/gb/gprs_ns2_sns.c

@@ -194,6 +194,21 @@ static struct gprs_ns2_vc *nsvc_by_ip6_elem(struct gprs_ns2_nse *nse,
 	return gprs_ns2_nsvc_by_sockaddr_nse(nse, &sa);
 }
 
+/*! Return the initial SNS remote socket address
+ * \param nse NS Entity
+ * \return address of the initial SNS connection; NULL in case of error
+ */
+const struct osmo_sockaddr *gprs_ns2_nse_sns_remote(struct gprs_ns2_nse *nse)
+{
+	struct ns2_sns_state *gss;
+
+	if (!nse->bss_sns_fi)
+		return NULL;
+
+	gss = (struct ns2_sns_state *) nse->bss_sns_fi->priv;
+	return &gss->initial;
+}
+
 /*! called when a nsvc is beeing freed */
 void ns2_sns_free_nsvc(struct gprs_ns2_vc *nsvc)
 {

src/gb/libosmogb.map

@@ -102,6 +102,7 @@ gprs_ns2_ll_str_buf;
 gprs_ns2_ll_str_c;
 gprs_ns2_nse_by_nsei;
 gprs_ns2_nse_nsei;
+gprs_ns2_nse_sns_remote;
 gprs_ns2_nsvc_by_nsvci;
 gprs_ns2_nsvc_by_sockaddr;
 gprs_ns2_recv_prim;