Fix multi ifaces (for real this time); fix iface types; add logs; add…

… Free5GC interop.

go.mod

@@ -5,7 +5,7 @@ go 1.22.7
 require (
 	github.com/adrg/xdg v0.5.3
 	github.com/gin-gonic/gin v1.10.0
-	github.com/nextmn/go-pfcp-networking v0.0.41-0.20241213191334-2767b639c015
+	github.com/nextmn/go-pfcp-networking v0.0.41
 	github.com/nextmn/json-api v0.0.14
 	github.com/nextmn/logrus-formatter v0.0.1
 	github.com/sirupsen/logrus v1.9.3

go.sum

@@ -48,10 +48,8 @@ github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9Gz0M=
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
-github.com/nextmn/go-pfcp-networking v0.0.41-0.20241212103129-24fe84808302 h1:NlmeMncMd72Qf0jTnXLPxHnXVB07tGycVn7Nrvx4YXw=
-github.com/nextmn/go-pfcp-networking v0.0.41-0.20241212103129-24fe84808302/go.mod h1:KYoKLiltDmHL2YMU5mz2k/E1xMoz4TpmzTz6Nr5u5gA=
-github.com/nextmn/go-pfcp-networking v0.0.41-0.20241213191334-2767b639c015 h1:0ICHKYmbOXM2QB5D34rL1kfkAyMdqJZ3E8zZPx02bCg=
-github.com/nextmn/go-pfcp-networking v0.0.41-0.20241213191334-2767b639c015/go.mod h1:KYoKLiltDmHL2YMU5mz2k/E1xMoz4TpmzTz6Nr5u5gA=
+github.com/nextmn/go-pfcp-networking v0.0.41 h1:vA8TfjlxZMxZIZiJ3eEdllwYjmBurvZvD9J4xcCPheo=
+github.com/nextmn/go-pfcp-networking v0.0.41/go.mod h1:KYoKLiltDmHL2YMU5mz2k/E1xMoz4TpmzTz6Nr5u5gA=
 github.com/nextmn/json-api v0.0.14 h1:m4uHOVcXsxkXoxbrhqemLTRG4T86eYkejjirew1nDUU=
 github.com/nextmn/json-api v0.0.14/go.mod h1:CQXeNPj9MDGsEExtnqJFIGjLgZAKsmOoO2fy+mep7Ak=
 github.com/nextmn/logrus-formatter v0.0.1 h1:Bsf78jjiEESc+rV8xE6IyKj4frDPGMwXFNrLQzm6A1E=

internal/smf/smf.go

@@ -108,7 +108,7 @@ func (smf *Smf) CreateSessionDownlink(ctx context.Context, ueCtrl jsonapi.Contro
 		if i == 0 {
 			upf_iface, err = upf.GetN3()
 		} else if i != len(slice.Upfs)-1 {
-			upf_iface, err = upf.GetN6()
+			upf_iface, err = upf.GetN9()
 		}
 		if err != nil {
 			return nil, err
@@ -158,11 +158,24 @@ func (smf *Smf) CreateSessionUplink(ctx context.Context, ueCtrl jsonapi.ControlU
 	var upfa_iface netip.Addr
 	if len(slice.Upfs) == 1 {
 		upfa_iface, err = upfa.GetN3()
+		if err != nil {
+			logrus.WithError(err).WithFields(logrus.Fields{
+				"upf":   upfa_ctrl,
+				"iface": "n3",
+				"type":  "anchor",
+			}).Error("Could not prepare session uplink path")
+			return nil, err
+		}
 	} else {
-		upfa_iface, err = upfa.GetN6()
-	}
-	if err != nil {
-		return nil, err
+		upfa_iface, err = upfa.GetN9()
+		if err != nil {
+			logrus.WithError(err).WithFields(logrus.Fields{
+				"upf":   upfa_ctrl,
+				"iface": "n9",
+				"type":  "anchor",
+			}).Error("Could not prepare session uplink path")
+			return nil, err
+		}
 	}
 	last_fteid, err := upfa.CreateUplinkAnchor(ctx, ueIpAddr, dnn, upfa_iface)
 	if err != nil {
@@ -183,17 +196,32 @@ func (smf *Smf) CreateSessionUplink(ctx context.Context, ueCtrl jsonapi.ControlU
 		var upf_iface netip.Addr
 		if i == 0 {
 			upf_iface, err = upf.GetN3()
+			if err != nil {
+				logrus.WithError(err).WithFields(logrus.Fields{
+					"upf":   upf_ctrl,
+					"iface": "n3",
+					"type":  "inter",
+				}).Error("Could not prepare session uplink path")
+				return nil, err
+			}
 		} else {
-			upf_iface, err = upf.GetN6()
-		}
-		if err != nil {
-			return nil, err
+			upf_iface, err = upf.GetN9()
+			if err != nil {
+				logrus.WithError(err).WithFields(logrus.Fields{
+					"upf":   upf_ctrl,
+					"iface": "n9",
+					"type":  "inter",
+				}).Error("Could not prepare session uplink path")
+				return nil, err
+			}
 		}
 		last_fteid, err = upf.CreateUplinkIntermediate(ctx, ueIpAddr, dnn, upf_iface, last_fteid)
 		if err != nil {
+			logrus.WithError(err).Error("Could not create uplink intermediate")
 			return nil, err
 		}
 		if err := upf.CreateSession(ueIpAddr); err != nil {
+			logrus.WithError(err).Error("Could not create session uplink")
 			return nil, err
 		}
 	}

internal/smf/upf.go

@@ -51,9 +51,9 @@ func (upf *Upf) GetN3() (netip.Addr, error) {
 	return netip.Addr{}, ErrInterfaceNotFound
 }
 
-func (upf *Upf) GetN6() (netip.Addr, error) {
+func (upf *Upf) GetN9() (netip.Addr, error) {
 	for addr, iface := range upf.interfaces {
-		if iface.IsN6() {
+		if iface.IsN9() {
 			return addr, nil
 		}
 	}
@@ -135,6 +135,7 @@ func (upf *Upf) CreateUplinkIntermediateWithFteid(ueIp netip.Addr, dnn string, l
 			),
 		),
 	))
+	// TODO: QER, to avoid wrong gtp size set by F5GC's UPF
 }
 
 func (upf *Upf) CreateUplinkAnchor(ctx context.Context, ueIp netip.Addr, dnn string, listenInterface netip.Addr) (*Fteid, error) {
@@ -200,6 +201,7 @@ func (upf *Upf) UpdateDownlinkAnchor(ueIp netip.Addr, dnn string, forwardFteid *
 			),
 		),
 	))
+	// TODO: QER, to avoid wrong gtp size set by F5GC's UPF
 }
 
 func (upf *Upf) UpdateDownlinkIntermediate(ctx context.Context, ueIp netip.Addr, dnn string, listenInterface netip.Addr, forwardFteid *Fteid) (*Fteid, error) {
@@ -223,7 +225,20 @@ func (upf *Upf) UpdateDownlinkIntermediateWithFteid(ueIp netip.Addr, dnn string,
 			ie.NewSourceInterface(ie.SrcInterfaceCore),
 			ie.NewFTEID(FteidTypeIPv4, listenFteid.Teid, listenFteid.Addr.AsSlice(), nil, 0),
 			ie.NewNetworkInstance(dnn),
-			ie.NewUEIPAddress(UEIpAddrTypeIPv4, ueIp.String(), "", 0, 0),
+			// Free5GC's UPF seems to drop GTP packets, when UE IP Address is present
+			// and for downlink only
+			// According to TS 129.244 version 17.4.0, section 7.5.2.2, table 7.5.2.2-2, p. 159:
+			// "If present, this IE shall identify the UE IP address as
+			// the source or destination IP address to match for the incoming packet"
+			// Here, it seems that when the packet is GTP encapsulated, only the source address is checked.
+			// This is a bug.
+			// As a workaround, we don't add the UE IP Address in this case.
+			// Free5GC's SMF implementation has a similar workaround:
+			// https://github.com/free5gc/smf/blob/62925c4a5840f118b42f245b5fef492898f9f0bd/internal/context/datapath.go#L636-L640
+			// and the bug seems to be referenced as "FR5GC-1029" (but I have no link to the details of the issue)
+			// XXX: the following line may be uncommented if the bug is fixed:
+
+			// ie.NewUEIPAddress(UEIpAddrTypeIPv4, ueIp.String(), "", 0, 0),
 		),
 		ie.NewOuterHeaderRemoval(OuterHeaderRemoveGtpuUdpIpv4, 0),
 		ie.NewFARID(r.currentfarid),
@@ -242,6 +257,7 @@ func (upf *Upf) UpdateDownlinkIntermediateWithFteid(ueIp netip.Addr, dnn string,
 			),
 		),
 	))
+	// TODO: QER, to avoid wrong gtp size set by F5GC's UPF
 }
 
 func (upf *Upf) CreateSession(ue netip.Addr) error {

internal/smf/upf_interface.go

@@ -27,9 +27,10 @@ func NewUpfInterfaceMap(ifaces []config.Interface) map[netip.Addr]*UpfInterface
 	r := make(map[netip.Addr]*UpfInterface)
 	for _, v := range ifaces {
 		if i, ok := r[v.Addr]; ok {
-			i.Types = append(i.Types, v.Type)
+			r[v.Addr].Types = append(i.Types, v.Type)
+		} else {
+			r[v.Addr] = NewUpfInterface(v.Type)
 		}
-		r[v.Addr] = NewUpfInterface(v.Type)
 	}
 	return r
 }
@@ -43,9 +44,9 @@ func (iface *UpfInterface) IsN3() bool {
 	return false
 }
 
-func (iface *UpfInterface) IsN6() bool {
+func (iface *UpfInterface) IsN9() bool {
 	for _, t := range iface.Types {
-		if strings.ToLower(t) == "n6" {
+		if strings.ToLower(t) == "n9" {
 			return true
 		}
 	}