From c5a0aed52add2af7cda1f52227e3e35ddd797326 Mon Sep 17 00:00:00 2001
From: Louis Royer <infos.louis.royer@gmail.com>
Date: Thu, 5 Sep 2024 13:10:58 +0200
Subject: [PATCH] Fix bug with ForwardingParameters

---
 pfcp/api/far_interface.go |  2 +-
 pfcp/entity.go            | 59 ++++++++++++++++++++++-----------------
 pfcp/far.go               | 11 ++++++--
 3 files changed, 44 insertions(+), 28 deletions(-)

diff --git a/pfcp/api/far_interface.go b/pfcp/api/far_interface.go
index 471ea8b..bbe8702 100644
--- a/pfcp/api/far_interface.go
+++ b/pfcp/api/far_interface.go
@@ -12,6 +12,6 @@ type FARID = uint32
 type FARInterface interface {
 	ID() (FARID, error)
 	ApplyAction() *ie.IE
-	ForwardingParameters() *ie.IE
+	ForwardingParameters() (*ie.IE, error)
 	NewCreateFAR() *ie.IE
 }
diff --git a/pfcp/entity.go b/pfcp/entity.go
index 0d79760..38b0004 100644
--- a/pfcp/entity.go
+++ b/pfcp/entity.go
@@ -397,36 +397,45 @@ func (e *PFCPEntity) LogPFCPRules() {
 				}
 			}
 
-			ForwardingParametersIe := far.ForwardingParameters()
+			isFP := true
+			ForwardingParametersIe, err := far.ForwardingParameters()
+			if err != nil {
+				isFP = false
+
+			}
 			OuterHeaderCreationLabel := "No"
-			if ohc, err := ForwardingParametersIe.OuterHeaderCreation(); err == nil {
-				ohcb, _ := ohc.Marshal()
-				ohcIe := ie.New(ie.OuterHeaderCreation, ohcb)
-				switch {
-				case ohcIe.HasTEID() && ohcIe.HasIPv4():
-					OuterHeaderCreationLabel = fmt.Sprintf("[%s (%d)]", ohc.IPv4Address.String(), ohc.TEID)
-				case ohcIe.HasTEID() && ohcIe.HasIPv6():
-					OuterHeaderCreationLabel = fmt.Sprintf("[%s (%d)]", ohc.IPv6Address.String(), ohc.TEID)
-				default:
-					OuterHeaderCreationLabel = "Other"
+			if isFP {
+				if ohc, err := ForwardingParametersIe.OuterHeaderCreation(); err == nil {
+					ohcb, _ := ohc.Marshal()
+					ohcIe := ie.New(ie.OuterHeaderCreation, ohcb)
+					switch {
+					case ohcIe.HasTEID() && ohcIe.HasIPv4():
+						OuterHeaderCreationLabel = fmt.Sprintf("[%s (%d)]", ohc.IPv4Address.String(), ohc.TEID)
+					case ohcIe.HasTEID() && ohcIe.HasIPv6():
+						OuterHeaderCreationLabel = fmt.Sprintf("[%s (%d)]", ohc.IPv6Address.String(), ohc.TEID)
+					default:
+						OuterHeaderCreationLabel = "Other"
+					}
 				}
 			}
 
 			DestinationInterfaceLabel := "Not defined"
-			if destination, err := ForwardingParametersIe.DestinationInterface(); err == nil {
-				switch destination {
-				case ie.DstInterfaceAccess:
-					DestinationInterfaceLabel = "Access"
-				case ie.DstInterfaceCore:
-					DestinationInterfaceLabel = "Core"
-				case ie.DstInterfaceSGiLANN6LAN:
-					DestinationInterfaceLabel = "SGi-LAN/N6-LAN"
-				case ie.DstInterfaceCPFunction:
-					DestinationInterfaceLabel = "CP Function"
-				case ie.DstInterfaceLIFunction:
-					DestinationInterfaceLabel = "LI Function"
-				case ie.DstInterface5GVNInternal:
-					DestinationInterfaceLabel = "5G VN Internal"
+			if isFP {
+				if destination, err := ForwardingParametersIe.DestinationInterface(); err == nil {
+					switch destination {
+					case ie.DstInterfaceAccess:
+						DestinationInterfaceLabel = "Access"
+					case ie.DstInterfaceCore:
+						DestinationInterfaceLabel = "Core"
+					case ie.DstInterfaceSGiLANN6LAN:
+						DestinationInterfaceLabel = "SGi-LAN/N6-LAN"
+					case ie.DstInterfaceCPFunction:
+						DestinationInterfaceLabel = "CP Function"
+					case ie.DstInterfaceLIFunction:
+						DestinationInterfaceLabel = "LI Function"
+					case ie.DstInterface5GVNInternal:
+						DestinationInterfaceLabel = "5G VN Internal"
+					}
 				}
 			}
 
diff --git a/pfcp/far.go b/pfcp/far.go
index 2aa8353..f603774 100644
--- a/pfcp/far.go
+++ b/pfcp/far.go
@@ -6,6 +6,7 @@
 package pfcp_networking
 
 import (
+	"fmt"
 	"github.com/nextmn/go-pfcp-networking/pfcp/api"
 	"github.com/wmnsk/go-pfcp/ie"
 )
@@ -32,8 +33,14 @@ func (far *FAR) ApplyAction() *ie.IE {
 	return far.applyAction
 }
 
-func (far *FAR) ForwardingParameters() *ie.IE {
-	return far.forwardingParameters
+func (far *FAR) ForwardingParameters() (*ie.IE, error) {
+	// This IE shall be present when the Apply Action requests
+	// the packets to be forwarded. It may be present otherwise.
+	if far.ForwardingParameters == nil {
+		return nil, fmt.Errorf("No forwarding parameters ie")
+	}
+	return far.forwardingParameters, nil
+
 }
 
 func (far *FAR) NewCreateFAR() *ie.IE {