msc: add TC_attached_imsi_lu_unknown_tmsi()
The test currently fails with osmo-msc master. It uncovers the evil twin aspect
of osmo-msc's VLR, for an attached IMSI re-attaching with an unknown TMSI.
Related: OS#4721
Change-Id: Ia53733fc5bc414b0e3d3897f25b549f5183c862d
diff --git a/msc/MSC_Tests.ttcn b/msc/MSC_Tests.ttcn
index a801db9..43c6287 100644
--- a/msc/MSC_Tests.ttcn
+++ b/msc/MSC_Tests.ttcn
@@ -962,6 +962,94 @@
vc_conn.done;
}
+/* Test LU by unknown TMSI, while the IMSI is already attached: osmo-msc should switch to the attached vlr_subscr. */
+private function f_tc_attached_imsi_lu_unknown_tmsi(charstring id, BSC_ConnHdlrPars pars) runs on BSC_ConnHdlr {
+ f_init_handler(pars);
+
+ var PDU_ML3_MS_NW l3_lu := f_build_lu_tmsi('56111111'O);
+ var PDU_DTAP_MT dtap_mt;
+
+ /* tell GSUP dispatcher to send this IMSI to us */
+ f_create_gsup_expect(hex2str(g_pars.imsi));
+
+ /* Send BSSAP_Conn_Req with COMPL L3 INFO to MSC */
+ f_cl3_or_initial_ue(l3_lu);
+
+ /* Send Early Classmark, just for the fun of it */
+ BSSAP.send(ts_BSSMAP_ClassmarkUpd(g_pars.cm2, g_pars.cm3));
+
+ /* Wait for + respond to ID REQ (IMSI) */
+ BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_MM_ID_Req(CM_ID_TYPE_IMSI)));
+ BSSAP.send(ts_PDU_DTAP_MO(ts_ML3_MO_MM_ID_Rsp_IMSI(g_pars.imsi)));
+ f_expect_common_id();
+
+ /* Expect MSC to do UpdateLocation to HLR; respond to it */
+ GSUP.receive(tr_GSUP_UL_REQ(g_pars.imsi));
+ GSUP.send(ts_GSUP_ISD_REQ(g_pars.imsi, g_pars.msisdn));
+ GSUP.receive(tr_GSUP_ISD_RES(g_pars.imsi));
+ GSUP.send(ts_GSUP_UL_RES(g_pars.imsi));
+
+ alt {
+ [] BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_LU_Acc)) {
+ BSSAP.send(ts_PDU_DTAP_MO(ts_ML3_MO_TmsiRealloc_Cmpl));
+ }
+ [] BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_LU_Rej)) {
+ setverdict(fail, "Expected LU ACK, but received REJ");
+ mtc.stop;
+ }
+ }
+
+ /* Wait for MM-Information (if enabled) */
+ f_expect_mm_info();
+
+ /* wait for normal teardown */
+ f_expect_clear();
+
+ /* Now the same IMSI is still attached in the VLR, and a LU with an unknown TMSI reveals the same IMSI only
+ * later during ID Response. osmo-msc first creates a new vlr_subscr for the unknown TMSI, and as soon as the
+ * IMSI becomes known, must notice that this IMSI is still regarded as attached, and must not create evil twins.
+ */
+
+ /* (since the TMSI Reallocation happened, we could do this with exactly the same TMSI as above, but for test
+ * readability just use a different one.) */
+ l3_lu := f_build_lu_tmsi('56222222'O);
+ f_cl3_or_initial_ue(l3_lu);
+
+ /* Wait for + respond to ID REQ (IMSI) */
+ BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_MM_ID_Req(CM_ID_TYPE_IMSI)));
+ BSSAP.send(ts_PDU_DTAP_MO(ts_ML3_MO_MM_ID_Rsp_IMSI(g_pars.imsi)));
+ f_expect_common_id();
+
+ /* Expect MSC to do UpdateLocation to HLR; respond to it */
+ GSUP.receive(tr_GSUP_UL_REQ(g_pars.imsi));
+ GSUP.send(ts_GSUP_ISD_REQ(g_pars.imsi, g_pars.msisdn));
+ GSUP.receive(tr_GSUP_ISD_RES(g_pars.imsi));
+ GSUP.send(ts_GSUP_UL_RES(g_pars.imsi));
+
+ alt {
+ [] BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_LU_Acc)) {
+ BSSAP.send(ts_PDU_DTAP_MO(ts_ML3_MO_TmsiRealloc_Cmpl));
+ }
+ [] BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_LU_Rej)) {
+ setverdict(fail, "Expected LU ACK, but received REJ");
+ mtc.stop;
+ }
+ }
+
+ /* Wait for MM-Information (if enabled) */
+ f_expect_mm_info();
+
+ /* wait for normal teardown */
+ f_expect_clear();
+}
+testcase TC_attached_imsi_lu_unknown_tmsi() runs on MTC_CT {
+ var BSC_ConnHdlr vc_conn;
+ f_init();
+
+ vc_conn := f_start_handler(refers(f_tc_attached_imsi_lu_unknown_tmsi), 56);
+ vc_conn.done;
+}
+
friend function f_imsi_detach_by_imsi() runs on BSC_ConnHdlr {
var MobileIdentityLV mi := valueof(ts_MI_IMSI_LV(g_pars.imsi));
@@ -6079,6 +6167,7 @@
execute( TC_lu_disconnect() );
execute( TC_lu_by_imei() );
execute( TC_lu_by_tmsi_noauth_unknown() );
+ execute( TC_attached_imsi_lu_unknown_tmsi() );
execute( TC_imsi_detach_by_imsi() );
execute( TC_imsi_detach_by_tmsi() );
execute( TC_imsi_detach_by_imei() );