Fixing crash when multiple instances of AMF are run (#126)

* Fixing crash when multiple instances of AMF are run

Delaying the null reference set to make sure there is no
inflight packet in the pipeline

* Reset security context available flag

Dockerfile

@@ -8,6 +8,7 @@ FROM golang:1.18.3-stretch AS builder
 LABEL maintainer="ONF <[email protected]>"
 
 #RUN apt remove cmdtest yarn
+RUN echo "deb http://archive.debian.org/debian stretch main" > /etc/apt/sources.list
 RUN apt-get update
 RUN apt-get -y install apt-transport-https ca-certificates
 RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg > pubkey.gpg

context/amf_ue.go

@@ -507,13 +507,17 @@ func (ue *AmfUe) DetachRanUe(anType models.AccessType) {
 func (ue *AmfUe) AttachRanUe(ranUe *RanUe) {
 	/* detach any RanUe associated to it */
 	oldRanUe := ue.RanUe[ranUe.Ran.AnType]
-	if oldRanUe != nil {
-		oldRanUe.Log.Infof("Detached UeContext from OldRanUe")
-		ue.RanUe[ranUe.Ran.AnType].AmfUe = nil
-	}
 	ue.RanUe[ranUe.Ran.AnType] = ranUe
 	ranUe.AmfUe = ue
 
+	go func() {
+		time.Sleep(time.Second * 2)
+		if oldRanUe != nil {
+			oldRanUe.Log.Infof("Detached UeContext from OldRanUe")
+			oldRanUe.AmfUe = nil
+		}
+	}()
+
 	// set log information
 	ue.NASLog = logger.NasLog.WithField(logger.FieldAmfUeNgapID, fmt.Sprintf("AMF_UE_NGAP_ID:%d", ranUe.AmfUeNgapId))
 	ue.GmmLog = logger.GmmLog.WithField(logger.FieldAmfUeNgapID, fmt.Sprintf("AMF_UE_NGAP_ID:%d", ranUe.AmfUeNgapId))

context/db.go

@@ -175,6 +175,7 @@ func DbFetch(collName string, filter bson.M) *AmfUe {
 	ue.ProducerLog = logger.ProducerLog.WithField(logger.FieldSupi, fmt.Sprintf("SUPI:%s", ue.Supi))
 	ue.AmfInstanceName = os.Getenv("HOSTNAME")
 	ue.AmfInstanceIp = os.Getenv("POD_IP")
+	ue.TxLog.Errorln("amfue fetched")
 	return ue
 }
 

nas/nas_security/security.go

@@ -204,6 +204,7 @@ func Decode(ue *context.AmfUe, accessType models.AccessType, payload []byte) (*n
 		if ue.SecurityContextAvailable && ue.RanUe[accessType].RRCEstablishmentCause != "0" {
 			ue.NASLog.Warnln("Received Plain NAS message")
 			ue.MacFailed = false
+			ue.SecurityContextAvailable = false
 			if err := msg.PlainNasDecode(&payload); err != nil {
 				return nil, err
 			}

ngap/dispatcher.go

@@ -99,7 +99,7 @@ func DispatchLb(sctplbMsg *sdcoreAmfServer.SctplbMessage, Amf2RanMsgChan chan *s
 	/* uecontext is found, submit the message to transaction queue*/
 	if ranUe != nil && ranUe.AmfUe != nil {
 		ranUe.AmfUe.SetEventChannel(NgapMsgHandler)
-		ranUe.AmfUe.TxLog.Infof("Uecontext found. queuing ngap message to uechannel")
+		//ranUe.AmfUe.TxLog.Infof("Uecontext found. queuing ngap message to uechannel")
 		ranUe.AmfUe.EventChannel.UpdateNgapHandler(NgapMsgHandler)
 		ngapMsg := context.NgapMsg{
 			Ran:       ran,