S-TMSI handling in Initial UE Message

src/gnb/ngap/nas.cpp

@@ -24,7 +24,8 @@
 namespace nr::gnb
 {
 
-void NgapTask::handleInitialNasTransport(int ueId, const OctetString &nasPdu, long rrcEstablishmentCause)
+void NgapTask::handleInitialNasTransport(int ueId, const OctetString &nasPdu, long rrcEstablishmentCause,
+                                         const std::optional<GutiMobileIdentity> &sTmsi)
 {
     m_logger->debug("Initial NAS message received from UE[%d]", ueId);
 
@@ -54,25 +55,43 @@ void NgapTask::handleInitialNasTransport(int ueId, const OctetString &nasPdu, lo
         amfCtx->nextStream += 1;
     ueCtx->uplinkStream = amfCtx->nextStream;
 
+    std::vector<ASN_NGAP_InitialUEMessage_IEs *> ies;
+
     auto *ieEstablishmentCause = asn::New<ASN_NGAP_InitialUEMessage_IEs>();
     ieEstablishmentCause->id = ASN_NGAP_ProtocolIE_ID_id_RRCEstablishmentCause;
     ieEstablishmentCause->criticality = ASN_NGAP_Criticality_ignore;
     ieEstablishmentCause->value.present = ASN_NGAP_InitialUEMessage_IEs__value_PR_RRCEstablishmentCause;
     ieEstablishmentCause->value.choice.RRCEstablishmentCause = rrcEstablishmentCause;
+    ies.push_back(ieEstablishmentCause);
 
     auto *ieCtxRequest = asn::New<ASN_NGAP_InitialUEMessage_IEs>();
     ieCtxRequest->id = ASN_NGAP_ProtocolIE_ID_id_UEContextRequest;
     ieCtxRequest->criticality = ASN_NGAP_Criticality_ignore;
     ieCtxRequest->value.present = ASN_NGAP_InitialUEMessage_IEs__value_PR_UEContextRequest;
     ieCtxRequest->value.choice.UEContextRequest = ASN_NGAP_UEContextRequest_requested;
+    ies.push_back(ieCtxRequest);
 
     auto *ieNasPdu = asn::New<ASN_NGAP_InitialUEMessage_IEs>();
     ieNasPdu->id = ASN_NGAP_ProtocolIE_ID_id_NAS_PDU;
     ieNasPdu->criticality = ASN_NGAP_Criticality_reject;
     ieNasPdu->value.present = ASN_NGAP_InitialUEMessage_IEs__value_PR_NAS_PDU;
     asn::SetOctetString(ieNasPdu->value.choice.NAS_PDU, nasPdu);
+    ies.push_back(ieNasPdu);
+
+    if (sTmsi)
+    {
+        auto *ieTmsi = asn::New<ASN_NGAP_InitialUEMessage_IEs>();
+        ieTmsi->id = ASN_NGAP_ProtocolIE_ID_id_FiveG_S_TMSI;
+        ieTmsi->criticality = ASN_NGAP_Criticality_reject;
+        ieTmsi->value.present = ASN_NGAP_InitialUEMessage_IEs__value_PR_FiveG_S_TMSI;
+
+        asn::SetBitStringInt<10>(sTmsi->amfSetId, ieTmsi->value.choice.FiveG_S_TMSI.aMFSetID);
+        asn::SetBitStringInt<6>(sTmsi->amfPointer, ieTmsi->value.choice.FiveG_S_TMSI.aMFPointer);
+        asn::SetOctetString4(ieTmsi->value.choice.FiveG_S_TMSI.fiveG_TMSI, sTmsi->tmsi);
+        ies.push_back(ieTmsi);
+    }
 
-    auto *pdu = asn::ngap::NewMessagePdu<ASN_NGAP_InitialUEMessage>({ieEstablishmentCause, ieCtxRequest, ieNasPdu});
+    auto *pdu = asn::ngap::NewMessagePdu<ASN_NGAP_InitialUEMessage>(ies);
     sendNgapUeAssociated(ueId, pdu);
 }
 

src/gnb/ngap/task.cpp

@@ -55,7 +55,7 @@ void NgapTask::onLoop()
         switch (w->present)
         {
         case NmGnbRrcToNgap::INITIAL_NAS_DELIVERY: {
-            handleInitialNasTransport(w->ueId, w->pdu, w->rrcEstablishmentCause);
+            handleInitialNasTransport(w->ueId, w->pdu, w->rrcEstablishmentCause, w->sTmsi);
             break;
         }
         case NmGnbRrcToNgap::UPLINK_NAS_DELIVERY: {

src/gnb/ngap/task.hpp

@@ -98,7 +98,8 @@ class NgapTask : public NtsTask
     bool handleSctpStreamId(int amfId, int stream, const ASN_NGAP_NGAP_PDU &pdu);
 
     /* NAS transport */
-    void handleInitialNasTransport(int ueId, const OctetString &nasPdu, long rrcEstablishmentCause);
+    void handleInitialNasTransport(int ueId, const OctetString &nasPdu, long rrcEstablishmentCause,
+                                   const std::optional<GutiMobileIdentity> &sTmsi);
     void handleUplinkNasTransport(int ueId, const OctetString &nasPdu);
     void receiveDownlinkNasTransport(int amfId, ASN_NGAP_DownlinkNASTransport *msg);
     void deliverDownlinkNas(int ueId, OctetString &&nasPdu);
@@ -108,7 +109,7 @@ class NgapTask : public NtsTask
     /* PDU session management */
     void receiveSessionResourceSetupRequest(int amfId, ASN_NGAP_PDUSessionResourceSetupRequest *msg);
     void receiveSessionResourceReleaseCommand(int amfId, ASN_NGAP_PDUSessionResourceReleaseCommand *msg);
-    std::optional<NgapCause> setupPduSessionResource(NgapUeContext* ue, PduSessionResource *resource);
+    std::optional<NgapCause> setupPduSessionResource(NgapUeContext *ue, PduSessionResource *resource);
 
     /* UE context management */
     void receiveInitialContextSetup(int amfId, ASN_NGAP_InitialContextSetupRequest *msg);

src/gnb/nts.hpp

@@ -204,6 +204,7 @@ struct NmGnbRrcToNgap : NtsMessage
 
     // INITIAL_NAS_DELIVERY
     long rrcEstablishmentCause{};
+    std::optional<GutiMobileIdentity> sTmsi{};
 
     explicit NmGnbRrcToNgap(PR present) : NtsMessage(NtsMessageType::GNB_RRC_TO_NGAP), present(present)
     {

src/gnb/rrc/connection.cpp

@@ -104,6 +104,8 @@ void GnbRrcTask::receiveRrcSetupComplete(int ueId, const ASN_RRC_RRCSetupComplet
     w->ueId = ueId;
     w->pdu = asn::GetOctetString(setupComplete->dedicatedNAS_Message);
     w->rrcEstablishmentCause = ue->establishmentCause;
+    w->sTmsi = std::nullopt; // TODO
+
     m_base->ngapTask->push(w);
 }