feat: SMF to support SDM Subscription and Unsubscription for UE Session

internal/context/context.go

@@ -79,6 +79,8 @@ type SMFContext struct {
 
 	// Each pdu session should have a unique charging id
 	ChargingIDGenerator *idgenerator.IDGenerator
+
+	Ues *Ues
 }
 
 func GenerateChargingID() int32 {
@@ -248,6 +250,8 @@ func InitSmfContext(config *factory.Config) {
 	smfContext.Locality = configuration.Locality
 
 	TeidGenerator = idgenerator.NewGenerator(1, math.MaxUint32)
+
+	smfContext.Ues = InitSmfUeData()
 }
 
 func InitSMFUERouting(routingConfig *factory.RoutingConfig) {

internal/context/sm_ue.go

@@ -0,0 +1,100 @@
+package context
+
+import "sync"
+
+type UeData struct {
+	PduSessionCount   int    // store number of PDU Sessions for each UE
+	SdmSubscriptionId string // store SDM Subscription ID per UE
+}
+
+type Ues struct {
+	ues map[string]UeData // map to store UE data with SUPI as key
+	mu  sync.Mutex        // mutex for concurrent access
+}
+
+func InitSmfUeData() *Ues {
+	return &Ues{
+		ues: make(map[string]UeData),
+	}
+}
+
+// IncrementPduSessionCount increments the PDU session count for a given UE.
+func (u *Ues) IncrementPduSessionCount(ueId string) {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	ueData := u.ues[ueId]
+	ueData.PduSessionCount++
+	u.ues[ueId] = ueData
+}
+
+// DecrementPduSessionCount decrements the PDU session count for a given UE.
+func (u *Ues) DecrementPduSessionCount(ueId string) {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	ueData := u.ues[ueId]
+	if ueData.PduSessionCount > 0 {
+		ueData.PduSessionCount--
+		u.ues[ueId] = ueData
+	}
+}
+
+// SetSubscriptionId sets the SDM subscription ID for a given UE.
+func (u *Ues) SetSubscriptionId(ueId, subscriptionId string) {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	ueData := u.ues[ueId]
+	ueData.SdmSubscriptionId = subscriptionId
+	u.ues[ueId] = ueData
+}
+
+// GetSubscriptionId returns the SDM subscription ID for a given UE.
+func (u *Ues) GetSubscriptionId(ueId string) string {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	return u.ues[ueId].SdmSubscriptionId
+}
+
+// GetUeData returns the data for a given UE.
+func (u *Ues) GetUeData(ueId string) UeData {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	return u.ues[ueId]
+}
+
+// DeleteUe deletes a UE.
+func (u *Ues) DeleteUe(ueId string) {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	delete(u.ues, ueId)
+}
+
+// UeExists checks if a UE already exists.
+func (u *Ues) UeExists(ueId string) bool {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	_, exists := u.ues[ueId]
+	return exists
+}
+
+// IsLastPduSession checks if it is the last PDU session for a given UE.
+func (u *Ues) IsLastPduSession(ueID string) bool {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	return u.ues[ueID].PduSessionCount == 1
+}
+
+// GetPduSessionCount returns the number of sessions for a given UE.
+func (u *Ues) GetPduSessionCount(ueId string) int {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+
+	return u.ues[ueId].PduSessionCount
+}

internal/sbi/consumer/udm_service.go

@@ -199,3 +199,124 @@ func (s *nudmService) GetSmData(ctx context.Context, supi string,
 
 	return sessSubData, rsp, err
 }
+
+func (s *nudmService) Subscribe(ctx context.Context, smCtx *smf_context.SMContext, smPlmnID *models.PlmnId) (
+	*models.ProblemDetails, error,
+) {
+	var client *Nudm_SubscriberDataManagement.APIClient
+	for _, service := range *s.consumer.Context().UDMProfile.NfServices {
+		if service.ServiceName == models.ServiceName_NUDM_SDM {
+			sdmUri := util.SearchNFServiceUri(smf_context.GetSelf().UDMProfile, models.ServiceName_NUDM_SDM,
+				models.NfServiceStatus_REGISTERED)
+			if sdmUri == "" {
+				return nil, errors.Errorf("SMF can not select an UDM by NRF: SearchNFServiceUri failed")
+			}
+
+			SDMConf := Nudm_SubscriberDataManagement.NewConfiguration()
+			SDMConf.SetBasePath(sdmUri)
+
+			client = Nudm_SubscriberDataManagement.NewAPIClient(SDMConf)
+		}
+	}
+
+	if client == nil {
+		return nil, fmt.Errorf("sdm client failed")
+	}
+
+	sdmSubscription := models.SdmSubscription{
+		NfInstanceId: smf_context.GetSelf().NfInstanceID,
+		PlmnId:       smPlmnID,
+	}
+
+	resSubscription, httpResp, localErr := client.SubscriptionCreationApi.Subscribe(
+		ctx, smCtx.Supi, sdmSubscription)
+	defer func() {
+		if httpResp != nil {
+			if rspCloseErr := httpResp.Body.Close(); rspCloseErr != nil {
+				logger.ConsumerLog.Errorf("Subscribe response body cannot close: %+v",
+					rspCloseErr)
+			}
+		}
+	}()
+
+	if localErr == nil {
+		smf_context.GetSelf().Ues.SetSubscriptionId(smCtx.Supi, resSubscription.SubscriptionId)
+		logger.PduSessLog.Infoln("SDM Subscription Successful UE:", smCtx.Supi, "SubscriptionId:",
+			resSubscription.SubscriptionId)
+	} else if httpResp != nil {
+		if httpResp.Status != localErr.Error() {
+			return nil, localErr
+		}
+		problem := localErr.(openapi.GenericOpenAPIError).Model().(models.ProblemDetails)
+		return &problem, nil
+	} else {
+		return nil, openapi.ReportError("server no response")
+	}
+
+	smf_context.GetSelf().Ues.IncrementPduSessionCount(smCtx.Supi)
+	return nil, nil
+}
+
+func (s *nudmService) UnSubscribe(smCtx *smf_context.SMContext) (
+	*models.ProblemDetails, error,
+) {
+	ctx, _, oauthErr := smf_context.GetSelf().GetTokenCtx(models.ServiceName_NUDM_SDM, models.NfType_UDM)
+	if oauthErr != nil {
+		return nil, fmt.Errorf("Get Token Context Error[%v]", oauthErr)
+	}
+
+	if smf_context.GetSelf().Ues.IsLastPduSession(smCtx.Supi) {
+		var client *Nudm_SubscriberDataManagement.APIClient
+		for _, service := range *s.consumer.Context().UDMProfile.NfServices {
+			if service.ServiceName == models.ServiceName_NUDM_SDM {
+				sdmUri := util.SearchNFServiceUri(smf_context.GetSelf().UDMProfile, models.ServiceName_NUDM_SDM,
+					models.NfServiceStatus_REGISTERED)
+				if sdmUri == "" {
+					return nil, errors.Errorf("SMF can not select an UDM by NRF: SearchNFServiceUri failed")
+				}
+
+				SDMConf := Nudm_SubscriberDataManagement.NewConfiguration()
+				SDMConf.SetBasePath(sdmUri)
+
+				client = Nudm_SubscriberDataManagement.NewAPIClient(SDMConf)
+			}
+		}
+
+		if client == nil {
+			return nil, fmt.Errorf("sdm client failed")
+		}
+
+		subscriptionId := smf_context.GetSelf().Ues.GetSubscriptionId(smCtx.Supi)
+
+		httpResp, localErr := client.SubscriptionDeletionApi.Unsubscribe(ctx, smCtx.Supi, subscriptionId)
+		defer func() {
+			if httpResp != nil {
+				if rspCloseErr := httpResp.Body.Close(); rspCloseErr != nil {
+					logger.PduSessLog.Errorf("Unsubscribe response body cannot close: %+v",
+						rspCloseErr)
+				}
+			}
+		}()
+		if localErr == nil {
+			logger.PduSessLog.Infoln("SDM UnSubscription Successful UE:", smCtx.Supi, "SubscriptionId:",
+				subscriptionId)
+		} else if httpResp != nil {
+
+			if httpResp.Status != localErr.Error() {
+				return nil, localErr
+			}
+			problem := localErr.(openapi.GenericOpenAPIError).Model().(models.ProblemDetails)
+
+			return &problem, nil
+
+		} else {
+			return nil, openapi.ReportError("server no response")
+		}
+		smf_context.GetSelf().Ues.DeleteUe(smCtx.Supi)
+
+	} else {
+		smf_context.GetSelf().Ues.DecrementPduSessionCount(smCtx.Supi)
+	}
+
+	return nil, nil
+}

internal/sbi/processor/pdu_session.go

@@ -121,6 +121,17 @@ func (p *Processor) HandlePDUSessionSMContextCreate(
 		}
 	}
 
+	if !smf_context.GetSelf().Ues.UeExists(smContext.Supi) {
+		if problemDetails, err := p.Consumer().
+			Subscribe(ctx, smContext, smPlmnID); problemDetails != nil {
+			smContext.Log.Errorln("SDM Subscription Failed Problem:", problemDetails)
+		} else if err != nil {
+			smContext.Log.Errorln("SDM Subscription Error:", err)
+		}
+	} else {
+		smf_context.GetSelf().Ues.IncrementPduSessionCount(smContext.Supi)
+	}
+
 	establishmentRequest := m.PDUSessionEstablishmentRequest
 	if err := HandlePDUSessionEstablishmentRequest(smContext, establishmentRequest); err != nil {
 		smContext.Log.Errorf("PDU Session Establishment fail by %s", err)
@@ -325,6 +336,15 @@ func (p *Processor) HandlePDUSessionSMContextUpdate(
 				}
 			}
 
+			if smf_context.GetSelf().Ues.UeExists(smContext.Supi) {
+				problemDetails, err := p.Consumer().UnSubscribe(smContext)
+				if problemDetails != nil {
+					logger.PduSessLog.Errorf("SDM UnSubscription Failed Problem[%+v]", problemDetails)
+				} else if err != nil {
+					logger.PduSessLog.Errorf("SDM UnSubscription Error[%+v]", err)
+				}
+			}
+
 			if smContext.UeCmRegistered {
 				problemDetails, errUeCmDeregistration := p.Consumer().UeCmDeregistration(smContext)
 				if problemDetails != nil {
@@ -878,6 +898,15 @@ func (p *Processor) HandlePDUSessionSMContextRelease(
 		}
 	}
 
+	if smf_context.GetSelf().Ues.UeExists(smContext.Supi) {
+		problemDetails, err := p.Consumer().UnSubscribe(smContext)
+		if problemDetails != nil {
+			logger.PduSessLog.Errorf("SDM UnSubscription Failed Problem[%+v]", problemDetails)
+		} else if err != nil {
+			logger.PduSessLog.Errorf("SDM UnSubscription Error[%+v]", err)
+		}
+	}
+
 	if smContext.UeCmRegistered {
 		problemDetails, err := p.Consumer().UeCmDeregistration(smContext)
 		if problemDetails != nil {
@@ -969,6 +998,15 @@ func (p *Processor) HandlePDUSessionSMContextLocalRelease(
 		}
 	}
 
+	if smf_context.GetSelf().Ues.UeExists(smContext.Supi) {
+		problemDetails, err := p.Consumer().UnSubscribe(smContext)
+		if problemDetails != nil {
+			logger.PduSessLog.Errorf("SDM UnSubscription Failed Problem[%+v]", problemDetails)
+		} else if err != nil {
+			logger.PduSessLog.Errorf("SDM UnSubscription Error[%+v]", err)
+		}
+	}
+
 	if smContext.UeCmRegistered {
 		problemDetails, err := p.Consumer().UeCmDeregistration(smContext)
 		if problemDetails != nil {

internal/sbi/processor/sm_common.go

@@ -15,6 +15,15 @@ func (p *Processor) RemoveSMContextFromAllNF(smContext *smf_context.SMContext, s
 		}
 	}
 
+	if smf_context.GetSelf().Ues.UeExists(smContext.Supi) {
+		problemDetails, err := p.Consumer().UnSubscribe(smContext)
+		if problemDetails != nil {
+			smContext.Log.Errorf("SDM UnSubscription Failed Problem[%+v]", problemDetails)
+		} else if err != nil {
+			smContext.Log.Errorf("SDM UnSubscription Error[%+v]", err)
+		}
+	}
+
 	// Because the amfUE who called this SMF API is being locked until the API Handler returns,
 	// sending SMContext Status Notification should run asynchronously
 	// so that this function returns immediately.