UE RRC release and radio link failure handling

src/ue/mm/base.cpp

@@ -234,35 +234,6 @@ void NasMm::onSwitchUState(E5UState oldState, E5UState newState)
 {
 }
 
-void NasMm::receivePlmnSearchResponse(const std::string &gnbName)
-{
-    if (m_base->nodeListener)
-        m_base->nodeListener->onConnected(app::NodeType::UE, m_base->config->getNodeName(), app::NodeType::GNB,
-                                          gnbName);
-
-    m_logger->info("UE connected to gNB");
-
-    if (m_mmSubState == EMmSubState::MM_REGISTERED_PLMN_SEARCH ||
-        m_mmSubState == EMmSubState::MM_REGISTERED_NO_CELL_AVAILABLE)
-        switchMmState(EMmState::MM_REGISTERED, EMmSubState::MM_REGISTERED_NORMAL_SERVICE);
-    else if (m_mmSubState == EMmSubState::MM_DEREGISTERED_PLMN_SEARCH ||
-             m_mmSubState == EMmSubState::MM_DEREGISTERED_NO_CELL_AVAILABLE)
-        switchMmState(EMmState::MM_DEREGISTERED, EMmSubState::MM_DEREGISTERED_NORMAL_SERVICE);
-}
-
-void NasMm::receivePlmnSearchFailure()
-{
-    if (m_mmSubState == EMmSubState::MM_REGISTERED_PLMN_SEARCH)
-        switchMmState(EMmState::MM_REGISTERED, EMmSubState::MM_REGISTERED_NO_CELL_AVAILABLE);
-    else if (m_mmSubState == EMmSubState::MM_DEREGISTERED_PLMN_SEARCH)
-        switchMmState(EMmState::MM_DEREGISTERED, EMmSubState::MM_DEREGISTERED_NO_CELL_AVAILABLE);
-}
-
-void NasMm::receiveRrcConnectionSetup()
-{
-    switchCmState(ECmState::CM_CONNECTED);
-}
-
 void NasMm::onTimerExpire(nas::NasTimer &timer)
 {
     switch (timer.getCode())

src/ue/mm/mm.hpp

@@ -66,9 +66,13 @@ class NasMm
     void triggerMmCycle();
     void performMmCycle();
     void onTimerExpire(nas::NasTimer &timer);
-    void receivePlmnSearchResponse(const std::string &gnbName);
-    void receivePlmnSearchFailure();
-    void receiveRrcConnectionSetup();
+
+    /* Radio resource control */
+    void handlePlmnSearchResponse(const std::string &gnbName);
+    void handlePlmnSearchFailure();
+    void handleRrcConnectionSetup();
+    void handleRrcConnectionRelease();
+    void handleRadioLinkFailure();
 
     /* Transport */
     void sendNasMessage(const nas::PlainMmMessage &msg);

src/ue/mm/radio.cpp

+//
+// This file is a part of UERANSIM open source project.
+// Copyright (c) 2021 ALİ GÜNGÖR.
+//
+// The software and all associated files are licensed under GPL-3.0
+// and subject to the terms and conditions defined in LICENSE file.
+//
+
+#include "mm.hpp"
+#include <nas/utils.hpp>
+#include <ue/app/task.hpp>
+#include <ue/sm/sm.hpp>
+
+namespace nr::ue
+{
+
+void NasMm::handlePlmnSearchResponse(const std::string &gnbName)
+{
+    if (m_base->nodeListener)
+        m_base->nodeListener->onConnected(app::NodeType::UE, m_base->config->getNodeName(), app::NodeType::GNB,
+            gnbName);
+
+    m_logger->info("UE connected to gNB");
+
+    if (m_mmSubState == EMmSubState::MM_REGISTERED_PLMN_SEARCH ||
+        m_mmSubState == EMmSubState::MM_REGISTERED_NO_CELL_AVAILABLE)
+        switchMmState(EMmState::MM_REGISTERED, EMmSubState::MM_REGISTERED_NORMAL_SERVICE);
+    else if (m_mmSubState == EMmSubState::MM_DEREGISTERED_PLMN_SEARCH ||
+             m_mmSubState == EMmSubState::MM_DEREGISTERED_NO_CELL_AVAILABLE)
+        switchMmState(EMmState::MM_DEREGISTERED, EMmSubState::MM_DEREGISTERED_NORMAL_SERVICE);
+}
+
+void NasMm::handlePlmnSearchFailure()
+{
+    if (m_mmSubState == EMmSubState::MM_REGISTERED_PLMN_SEARCH)
+        switchMmState(EMmState::MM_REGISTERED, EMmSubState::MM_REGISTERED_NO_CELL_AVAILABLE);
+    else if (m_mmSubState == EMmSubState::MM_DEREGISTERED_PLMN_SEARCH)
+        switchMmState(EMmState::MM_DEREGISTERED, EMmSubState::MM_DEREGISTERED_NO_CELL_AVAILABLE);
+}
+
+void NasMm::handleRrcConnectionSetup()
+{
+    switchCmState(ECmState::CM_CONNECTED);
+}
+
+void NasMm::handleRrcConnectionRelease()
+{
+    m_logger->err("TODO: handle RRC connection release");
+}
+
+void NasMm::handleRadioLinkFailure()
+{
+    m_logger->debug("Radio link failure detected");
+    handleRrcConnectionRelease();
+}
+
+}
\ No newline at end of file

src/ue/mr/task.cpp

@@ -68,7 +68,15 @@ void UeMrTask::onLoop()
             break;
         }
         case NwUeMrToMr::RLS_RELEASED: {
-            m_logger->warn("UE disconnected from gNB, RLS released [%s]", rls::CauseToString(w->cause));
+            if (rls::IsRlf(w->cause))
+            {
+                m_logger->err("Radio link failure with cause[%s]", rls::CauseToString(w->cause));
+                m_base->rrcTask->push(new NwUeMrToRrc(NwUeMrToRrc::RADIO_LINK_FAILURE));
+            }
+            else
+            {
+                m_logger->debug("UE disconnected from gNB [%s]", rls::CauseToString(w->cause));
+            }
             break;
         }
         case NwUeMrToMr::RLS_SEARCH_FAILURE: {
@@ -113,6 +121,10 @@ void UeMrTask::onLoop()
             m_rlsEntity->onUplinkDelivery(rls::EPayloadType::RRC, std::move(stream));
             break;
         }
+        case NwUeRrcToMr::RRC_CONNECTION_RELEASE: {
+            m_rlsEntity->localReleaseConnection(rls::ECause::RRC_RELEASE);
+            break;
+        }
         }
         break;
     }

src/ue/nas/task.cpp

@@ -60,15 +60,15 @@ void NasTask::onLoop()
         switch (w->present)
         {
         case NwUeRrcToNas::RRC_CONNECTION_SETUP: {
-            mm->receiveRrcConnectionSetup();
+            mm->handleRrcConnectionSetup();
             break;
         }
         case NwUeRrcToNas::PLMN_SEARCH_RESPONSE: {
-            mm->receivePlmnSearchResponse(w->gnbName);
+            mm->handlePlmnSearchResponse(w->gnbName);
             break;
         }
         case NwUeRrcToNas::PLMN_SEARCH_FAILURE: {
-            mm->receivePlmnSearchFailure();
+            mm->handlePlmnSearchFailure();
             break;
         }
         case NwUeRrcToNas::NAS_DELIVERY: {
@@ -78,6 +78,14 @@ void NasTask::onLoop()
                 mm->receiveNasMessage(*nasMessage);
             break;
         }
+        case NwUeRrcToNas::RRC_CONNECTION_RELEASE: {
+            mm->handleRrcConnectionRelease();
+            break;
+        }
+        case NwUeRrcToNas::RADIO_LINK_FAILURE: {
+            mm->handleRadioLinkFailure();
+            break;
+        }
         }
         break;
     }

src/ue/nts.hpp

@@ -66,6 +66,7 @@ struct NwUeMrToRrc : NtsMessage
         PLMN_SEARCH_RESPONSE,
         PLMN_SEARCH_FAILURE,
         RRC_PDU_DELIVERY,
+        RADIO_LINK_FAILURE
     } present;
 
     // PLMN_SEARCH_RESPONSE
@@ -156,6 +157,8 @@ struct NwUeRrcToNas : NtsMessage
         PLMN_SEARCH_RESPONSE,
         PLMN_SEARCH_FAILURE,
         RRC_CONNECTION_SETUP,
+        RRC_CONNECTION_RELEASE,
+        RADIO_LINK_FAILURE,
     } present;
 
     // NAS_DELIVERY
@@ -195,7 +198,8 @@ struct NwUeRrcToMr : NtsMessage
     enum PR
     {
         PLMN_SEARCH_REQUEST,
-        RRC_PDU_DELIVERY
+        RRC_PDU_DELIVERY,
+        RRC_CONNECTION_RELEASE,
     } present;
 
     // RRC_PDU_DELIVERY

src/ue/rrc/channel.cpp

@@ -255,13 +255,15 @@ void UeRrcTask::receiveRrcMessage(ASN_RRC_DL_DCCH_Message *msg)
     auto &c1 = msg->message.choice.c1;
     switch (c1->present)
     {
-    case ASN_RRC_DL_DCCH_MessageType__c1_PR_dlInformationTransfer: {
+    case ASN_RRC_DL_DCCH_MessageType__c1_PR_dlInformationTransfer:
         receiveDownlinkInformationTransfer(*c1->choice.dlInformationTransfer);
         break;
+    case ASN_RRC_DL_DCCH_MessageType__c1_PR_rrcRelease:
+        receiveRrcRelease(*c1->choice.rrcRelease);
+        break;
     default:
         break;
     }
-    }
 }
 
 void UeRrcTask::receiveRrcMessage(ASN_RRC_PCCH_Message *msg)

src/ue/rrc/handler.cpp

@@ -9,6 +9,7 @@
 #include "task.hpp"
 #include <asn/utils/utils.hpp>
 #include <rrc/encode.hpp>
+#include <ue/mr/task.hpp>
 #include <ue/nas/task.hpp>
 #include <ue/nts.hpp>
 #include <utils/common.hpp>
@@ -124,4 +125,13 @@ void UeRrcTask::receiveDownlinkInformationTransfer(const ASN_RRC_DLInformationTr
     m_base->nasTask->push(nw);
 }
 
+void UeRrcTask::receiveRrcRelease(const ASN_RRC_RRCRelease &msg)
+{
+    m_logger->debug("RRC Release received");
+    m_state = ERrcState::RRC_IDLE;
+
+    m_base->mrTask->push(new NwUeRrcToMr(NwUeRrcToMr::RRC_CONNECTION_RELEASE));
+    m_base->nasTask->push(new NwUeRrcToNas(NwUeRrcToNas::RRC_CONNECTION_RELEASE));
+}
+
 } // namespace nr::ue
\ No newline at end of file

src/ue/rrc/task.cpp

@@ -63,6 +63,10 @@ void UeRrcTask::onLoop()
             handleDownlinkRrc(w->channel, w->pdu);
             break;
         }
+        case NwUeMrToRrc::RADIO_LINK_FAILURE: {
+            handleRadioLinkFailure();
+            break;
+        }
         }
         break;
     }
@@ -91,4 +95,9 @@ void UeRrcTask::onLoop()
     delete msg;
 }
 
+void UeRrcTask::handleRadioLinkFailure()
+{
+    m_base->nasTask->push(new NwUeRrcToNas(NwUeRrcToNas::RADIO_LINK_FAILURE));
+}
+
 } // namespace nr::ue
\ No newline at end of file

src/ue/rrc/task.hpp

@@ -34,6 +34,7 @@ extern "C"
     struct ASN_RRC_ULInformationTransfer;
     struct ASN_RRC_RRCSetup;
     struct ASN_RRC_RRCReject;
+    struct ASN_RRC_RRCRelease;
 }
 
 namespace nr::ue
@@ -64,14 +65,17 @@ class UeRrcTask : public NtsTask
 
   private:
     /* Handlers */
-    void handleDownlinkRrc(rrc::RrcChannel channel, const OctetString& pdu);
+    void handleDownlinkRrc(rrc::RrcChannel channel, const OctetString &pdu);
     void deliverInitialNas(OctetString &&nasPdu, long establishmentCause);
     void deliverUplinkNas(OctetString &&nasPdu);
 
     void receiveRrcSetup(const ASN_RRC_RRCSetup &msg);
     void receiveRrcReject(const ASN_RRC_RRCReject &msg);
+    void receiveRrcRelease(const ASN_RRC_RRCRelease &msg);
     void receiveDownlinkInformationTransfer(const ASN_RRC_DLInformationTransfer &msg);
 
+    void handleRadioLinkFailure();
+
     /* RRC channel send message */
     void sendRrcMessage(ASN_RRC_BCCH_BCH_Message *msg);
     void sendRrcMessage(ASN_RRC_BCCH_DL_SCH_Message *msg);

src/urs/rls/ue_entity.cpp

@@ -8,9 +8,9 @@
 
 #include "ue_entity.hpp"
 
+#include <utility>
 #include <utils/common.hpp>
 #include <utils/constants.hpp>
-#include <utility>
 
 static const octet3 AppVersion = octet3{cons::Major, cons::Minor, cons::Patch};
 
@@ -226,13 +226,7 @@ void RlsUeEntity::onReceive(const InetAddress &address, const OctetString &pdu)
 void RlsUeEntity::releaseConnection(ECause cause)
 {
     sendReleaseIndication(cause);
-    state = EUeState::RELEASED;
-    nextSearch = 0;
-    ueToken = 0;
-    gnbToken = 0;
-    lastGnbHeartbeat = 0;
-    lastError = ECause::UNSPECIFIED;
-    onRelease(cause);
+    localReleaseConnection(cause);
 }
 
 void RlsUeEntity::resetEntity()
@@ -293,4 +287,15 @@ void RlsUeEntity::sendRlsMessage(const InetAddress &address, const RlsMessage &m
     sendRlsPdu(address, std::move(stream));
 }
 
+void RlsUeEntity::localReleaseConnection(ECause cause)
+{
+    state = EUeState::RELEASED;
+    nextSearch = 0;
+    ueToken = 0;
+    gnbToken = 0;
+    lastGnbHeartbeat = 0;
+    lastError = ECause::UNSPECIFIED;
+    onRelease(cause);
+}
+
 } // namespace rls
\ No newline at end of file

src/urs/rls/ue_entity.hpp

@@ -51,6 +51,7 @@ class RlsUeEntity
     void onUplinkDelivery(EPayloadType type, OctetString &&payload);
     void startGnbSearch();
     void releaseConnection(ECause cause);
+    void localReleaseConnection(ECause cause);
     void resetEntity();
 
   private: