From 773407e829e3f4b5d87a3d9b1956551aa804754a Mon Sep 17 00:00:00 2001
From: mamie1031 <sciencemamie@gmail.com>
Date: Thu, 9 Jan 2025 23:57:11 -0800
Subject: [PATCH] feat: Modify code for indirect communication in free5gc
 v3.4.4

---
 internal/context/context.go            |  4 ++
 internal/sbi/processor/nf_discovery.go | 75 ++++++++++++++++++++++++++
 pkg/factory/config.go                  |  1 +
 pkg/factory/factory.go                 |  7 +++
 4 files changed, 87 insertions(+)

diff --git a/internal/context/context.go b/internal/context/context.go
index 3dcea3f..73a789d 100644
--- a/internal/context/context.go
+++ b/internal/context/context.go
@@ -28,6 +28,7 @@ type NRFContext struct {
 	NrfCert          *x509.Certificate
 	NfRegistNum      int
 	nfRegistNumLock  sync.RWMutex
+	ScpUri           string
 }
 
 const (
@@ -47,6 +48,9 @@ func InitNrfContext() error {
 	logger.InitLog.Infof("nrfconfig Info: Version[%s] Description[%s]",
 		config.Info.Version, config.Info.Description)
 	configuration := config.Configuration
+	if configuration.ScpUri != "" {
+		nrfContext.ScpUri = configuration.ScpUri
+	}
 
 	nrfContext.NrfNfProfile.NfInstanceId = uuid.New().String()
 	nrfContext.NrfNfProfile.NfType = models.NfType_NRF
diff --git a/internal/sbi/processor/nf_discovery.go b/internal/sbi/processor/nf_discovery.go
index 2524077..659bbe4 100644
--- a/internal/sbi/processor/nf_discovery.go
+++ b/internal/sbi/processor/nf_discovery.go
@@ -50,6 +50,7 @@ func validateQueryParameters(queryParameters url.Values) bool {
 		"BSF":    true,
 		"CHF":    true,
 		"NWDAF":  true,
+		"SCP":    true,
 	}
 	var tgt, req string
 	if queryParameters["target-nf-type"] != nil {
@@ -173,6 +174,80 @@ func (p *Processor) NFDiscoveryProcedure(c *gin.Context, queryParameters url.Val
 	}
 	validityPeriod := 100
 
+	// Indirect Communication
+	// Only the following NF pairs support indirect communication
+	supportNFPairForIndirectCommunication := false
+	npPairs := map[string][]string{
+		"AMF":  {"AUSF", "SMF"},
+		"AUSF": {"UDM", "AMF"},
+		"UDM":  {"UDR", "AUSF"},
+		"UDR":  {"UDM", "NEF"},
+		"SMF":  {"AMF"},
+		"NEF":  {"UDR"},
+	}
+	sourceNF := ""
+	targetNF := ""
+	if values, exists := queryParameters["requester-nf-type"]; exists && len(values) > 0 {
+		sourceNF = values[0]
+	}
+	if values, exists := queryParameters["target-nf-type"]; exists && len(values) > 0 {
+		targetNF = values[0]
+	}
+
+	if validTargets, exists := npPairs[sourceNF]; exists {
+		for _, validTarget := range validTargets {
+			if validTarget == targetNF {
+				supportNFPairForIndirectCommunication = true
+			}
+		}
+
+	}
+	ScpUri := nrf_context.GetSelf().ScpUri
+	if ScpUri != "" && supportNFPairForIndirectCommunication {
+		// parse uri to host and port
+		parsedURL, err := url.Parse(ScpUri)
+		if err != nil {
+			logger.DiscLog.Errorln("Error parsing URL:", err)
+			return
+		}
+		host := parsedURL.Host
+		hostParts := strings.Split(host, ":")
+		if len(hostParts) != 2 {
+			logger.DiscLog.Errorln("Invalid host format, expected IP:PORT")
+			return
+		}
+		ScpIp := hostParts[0]
+		scpPortInt, err := strconv.Atoi(hostParts[1])
+		if err != nil {
+			logger.DiscLog.Errorln("Invalid port value: ", err)
+		}
+		logger.DiscLog.Infof("ScpIp: %v,  scpPortInt: %v", ScpIp, scpPortInt)
+		logger.DiscLog.Infof("Discovery with indirect communication, the message will pass to SCP: [%v]", ScpUri)
+		if len(nfProfilesStruct) > 0 {
+			for i := range nfProfilesStruct {
+				nfProfilesStruct[i].Ipv4Addresses[0] = ScpUri
+
+				if nfProfilesStruct[i].NfServices != nil {
+					for j := range *nfProfilesStruct[i].NfServices {
+						nfService := &(*nfProfilesStruct[i].NfServices)[j]
+
+						if nfService.IpEndPoints != nil {
+							for k := range *nfService.IpEndPoints {
+								ipEndPoint := &(*nfService.IpEndPoints)[k]
+								ipEndPoint.Ipv4Address = ScpIp
+								ipEndPoint.Port = int32(scpPortInt)
+							}
+						}
+						// for UDM search
+						if nfService.ApiPrefix != "" {
+							nfService.ApiPrefix = ScpUri
+						}
+					}
+				}
+			}
+		}
+
+	}
 	// Build SearchResult model
 	searchResult := &models.SearchResult{
 		ValidityPeriod: int32(validityPeriod),
diff --git a/pkg/factory/config.go b/pkg/factory/config.go
index d6a41bc..cab404c 100644
--- a/pkg/factory/config.go
+++ b/pkg/factory/config.go
@@ -61,6 +61,7 @@ type Configuration struct {
 	MongoDBUrl      string        `yaml:"MongoDBUrl" valid:"required"`
 	DefaultPlmnId   models.PlmnId `yaml:"DefaultPlmnId" valid:"required"`
 	ServiceNameList []string      `yaml:"serviceNameList,omitempty" valid:"required"`
+	ScpUri          string        `yaml:"scpUri,omitempty"`
 }
 
 type Logger struct {
diff --git a/pkg/factory/factory.go b/pkg/factory/factory.go
index d26b2d8..ffb951f 100644
--- a/pkg/factory/factory.go
+++ b/pkg/factory/factory.go
@@ -30,6 +30,13 @@ func InitConfigFactory(f string, cfg *Config) error {
 		if yamlErr := yaml.Unmarshal(content, cfg); yamlErr != nil {
 			return fmt.Errorf("[Factory] %+v", yamlErr)
 		}
+		// Check Communication Mode
+		if cfg.Configuration.ScpUri == "" {
+			logger.CfgLog.Infoln("Direct Communication Mode")
+		} else {
+			logger.CfgLog.Infof("Indirect Communication Mode, the control message will pass to SCP: [%v]", cfg.Configuration.ScpUri)
+		}
+
 	}
 
 	return nil