sgsn: Add user plane GTP testing (GTP->Gb and Gb->GTP)

Change-Id: Ifd62cca8cd9dbcffe4eac957db210ac13b8c633f
diff --git a/library/LLC_Templates.ttcn b/library/LLC_Templates.ttcn
index 7bc4088..086207c 100644
--- a/library/LLC_Templates.ttcn
+++ b/library/LLC_Templates.ttcn
@@ -20,6 +20,12 @@
 	pM := bool2bit(protected)
 }
 
+template (value) Control_field_U ts_LLC_CtrlU(BIT4 m_bits, BIT1 p_f) := {
+	mBits := m_bits,
+	pF := p_f,
+	format := '111'B
+}
+
 template Control_field_UI tr_LLC_CtrlUI(template uint9_t n_u,
 					template boolean encrypted := ?,
 					template boolean protected := ?) := {
@@ -30,6 +36,14 @@
 	pM := bool2bit_tmpl(protected)
 }
 
+template Control_field_U tr_LLC_CtrlU(template BIT4 m_bits := ?,
+					template BIT1 p_f := ?) := {
+	mBits := m_bits,
+	pF := p_f,
+	format := '111'B
+}
+
+
 template PDU_LLC ts_LLC_UI(octetstring payload, BIT4 sapi, BIT1 cr, uint9_t n_u,
 			   boolean encrypted := false, boolean protected := false) := {
 	pDU_LLC_UI := {
@@ -51,6 +65,19 @@
 	}
 }
 
+template PDU_LLC tr_LLC_XID(template XID_Information xid, template BIT4 sapi := ?,
+			    template BIT1 cr := ?, template BIT1 p_f := ?) := {
+	pDU_LLC_U := {
+		address_field := t_LLC_Addr(sapi, cr),
+		control_field := tr_LLC_CtrlU('1011'B, p_f),
+		information_field_U := {
+			xID := xid
+		},
+		fCS := '000000'O /* provided by decoder if FCS OK */
+	}
+}
+
+
 const BIT4 c_LLC_SAPI_LLGMM := '0001'B;
 const BIT4 c_LLC_SAPI_TOM2 := '0010'B;
 const BIT4 c_LLC_SAPI_LL3 := '0011'B;