[SDFAB-1110] Add support for application filter (#54)

* First commit

* Fix increment of internal loop

* Add QER gating parameters

* Refactor

* Fix gate status

* Fix gate status

* Refactor

* Allow to set gate status

* Fix short command

* Fix incorrect gate setting. Use app QER

* Partial implementation of app filter flag

* Address review comments

* Address review comments

* Add support for app-filter string

* Address review comments

* Address review comments

* Add copyright header

* Address review comments

api/pfcpsim.proto

@@ -13,9 +13,8 @@ message CreateSessionRequest {
   int32 baseID = 2;
   string nodeBAddress = 3;
   string ueAddressPool = 4;
-  string sdfFilter = 5;
+  string appFilter = 5;
   int32 qfi = 6; // Should be uint8
-  bool gateClosed = 7;
 }
 
 message ModifySessionRequest {

internal/pfcpctl/commands/services.go

@@ -11,10 +11,10 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-type associate struct {}
-type disassociate struct {}
+type associate struct{}
+type disassociate struct{}
 type configureRemoteAddresses struct {
-	RemotePeerAddress string `short:"r" long:"remote-peer-addr" default:"" description:"The remote PFCP agent address."`
+	RemotePeerAddress  string `short:"r" long:"remote-peer-addr" default:"" description:"The remote PFCP agent address."`
 	N3InterfaceAddress string `short:"n" long:"n3-addr" default:"" description:"The IPv4 address of the UPF's N3 interface"`
 }
 

internal/pfcpctl/commands/sessions.go

@@ -12,32 +12,31 @@ import (
 )
 
 type commonArgs struct {
-	Count int `short:"c" long:"count" default:"1" description:"The number of sessions to create"`
-	BaseID int `short:"i" long:"baseID"  default:"1" description:"The base ID to use"`
-	UePool string `short:"u" long:"ue-pool" default:"17.0.0.0/24" description:"The UE pool address"`
-	GnBAddress string `short:"g" long:"gnb-addr" description:"The (g/e)nodeB address"`
-	SDFfilter string `short:"s" long:"sdf-filter" description:"The SDF Filter to use"`
-	QFI        uint8 `short:"q" long:"qfi" description:"The QFI value for QERs. Max value 64."`
-	GateClosed bool  `short:"t" long:"gate-closed" description:"If set, the application QER gate status will be CLOSED"`
+	Count           int    `short:"c" long:"count" default:"1" description:"The number of sessions to create"`
+	BaseID          int    `short:"i" long:"baseID"  default:"1" description:"The base ID to use"`
+	UePool          string `short:"u" long:"ue-pool" default:"17.0.0.0/24" description:"The UE pool address"`
+	GnBAddress      string `short:"g" long:"gnb-addr" description:"The UE pool address"`
+	AppFilterString string `short:"a" long:"app-filter" description:"Specify an application filter. Format: '<Protocol>:<IP>/<SubnetMask>:<Port>-<Port>:<action>' . e.g.  'udp:10.0.0.0/8:80-88:allow'"`
+	QFI             uint8  `short:"q" long:"qfi" description:"The QFI value for QERs. Max value 64."`
 }
 
 type sessionCreate struct {
-	Args struct{
+	Args struct {
 		commonArgs
 	}
 }
 
 type sessionModify struct {
 	Args struct {
 		commonArgs
-		BufferFlag bool `short:"b" long:"buffer" description:"If set, downlink FARs will have the buffer flag set to true"`
+		BufferFlag   bool `short:"b" long:"buffer" description:"If set, downlink FARs will have the buffer flag set to true"`
 		NotifyCPFlag bool `short:"n" long:"notifycp" description:"If set, downlink FARs will have the notify CP flag set to true"`
 	}
 }
 
 type sessionDelete struct {
-	Args struct{
-		Count int `short:"c" long:"count" default:"1" description:"The number of sessions to create"`
+	Args struct {
+		Count  int `short:"c" long:"count" default:"1" description:"The number of sessions to create"`
 		BaseID int `short:"i" long:"baseID"  default:"1" description:"The base ID to use"`
 	}
 }
@@ -65,9 +64,8 @@ func (s *sessionCreate) Execute(args []string) error {
 		BaseID:        int32(s.Args.BaseID),
 		NodeBAddress:  s.Args.GnBAddress,
 		UeAddressPool: s.Args.UePool,
-		SdfFilter:     s.Args.SDFfilter,
-		Qfi: int32(s.Args.QFI),
-		GateClosed: s.Args.GateClosed,
+		AppFilter:     s.Args.AppFilterString,
+		Qfi:           int32(s.Args.QFI),
 	})
 
 	if err != nil {

internal/pfcpsim/helpers.go

@@ -4,11 +4,17 @@
 package pfcpsim
 
 import (
+	"fmt"
 	"net"
+	"strconv"
+	"strings"
 
 	"github.com/omec-project/pfcpsim/pkg/pfcpsim"
+	"github.com/wmnsk/go-pfcp/ie"
 )
 
+const sdfFilterFormat = "permit out %v from %v to assigned %v-%v"
+
 func connectPFCPSim() error {
 	if sim == nil {
 		localAddr, err := getLocalAddress(interfaceName)
@@ -71,3 +77,53 @@ func getLocalAddress(interfaceName string) (net.IP, error) {
 
 	return nil, pfcpsim.NewNoValidInterfaceError()
 }
+
+// parseAppFilter parses an application filter. Returns a tuple formed by a formatted SDF filter
+// and a uint8 representing the Application QER gate status. Returns error if fail occurs while validating the filter string.
+func parseAppFilter(filter string) (string, uint8, error) {
+	result := strings.Split(filter, ":")
+	if len(result) != 4 {
+		return "", 0, pfcpsim.NewInvalidFormatError("Parser was not able to generate the correct number of arguments." +
+			" Please make sure to use the right format")
+	}
+
+	proto, ipNetAddr, portRange, action := result[0], result[1], result[2], result[3]
+
+	if !(proto == "ip" || proto == "udp" || proto == "tcp") {
+		return "", 0, pfcpsim.NewInvalidFormatError("Unsupported or unknown protocol.")
+	}
+
+	_, _, err := net.ParseCIDR(ipNetAddr)
+	if err != nil {
+		return "", 0, pfcpsim.NewInvalidFormatError("IP and subnet mask.", err)
+	}
+
+	portList := strings.Split(portRange, "-")
+	if !(len(portList) == 2) {
+		return "", 0, pfcpsim.NewInvalidFormatError("Port range. Please make sure to use dash '-' to separate the two ports")
+	}
+
+	lowerPort, err := strconv.Atoi(portList[0])
+	if err != nil {
+		return "", 0, pfcpsim.NewInvalidFormatError("Port range.", err)
+	}
+
+	upperPort, err := strconv.Atoi(portList[1])
+	if err != nil {
+		return "", 0, pfcpsim.NewInvalidFormatError("Port range.", err)
+	}
+
+	if lowerPort > upperPort {
+		return "", 0, pfcpsim.NewInvalidFormatError("Port range. Lower port is greater than upper port")
+	}
+
+	if !(action == "allow" || action == "deny") {
+		return "", 0, pfcpsim.NewInvalidFormatError("Action. Please make sure to use 'allow' or 'deny'")
+	}
+
+	if action == "allow" {
+		return fmt.Sprintf(sdfFilterFormat, proto, ipNetAddr, lowerPort, upperPort), ie.GateStatusOpen, nil
+	}
+
+	return fmt.Sprintf(sdfFilterFormat, proto, ipNetAddr, lowerPort, upperPort), ie.GateStatusClosed, nil
+}

internal/pfcpsim/helpers_test.go

@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright 2022-present Open Networking Foundation
+
+package pfcpsim
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/wmnsk/go-pfcp/ie"
+)
+
+func Test_parseAppFilter(t *testing.T) {
+	type args struct {
+		filterString string
+	}
+
+	type want struct {
+		SDFFilter  string
+		gateStatus uint8
+	}
+
+	tests := []struct {
+		name    string
+		args    *args
+		want    *want
+		wantErr bool
+	}{
+		{name: "Correct app filter",
+			args: &args{
+				filterString: "udp:10.0.0.0/8:80-80:allow",
+			},
+			want: &want{
+				SDFFilter:  "permit out udp from 10.0.0.0/8 to assigned 80-80",
+				gateStatus: ie.GateStatusOpen,
+			},
+		},
+		{name: "Correct app filter with deny",
+			args: &args{
+				filterString: "udp:10.0.0.0/8:80-80:deny",
+			},
+			want: &want{
+				SDFFilter:  "permit out udp from 10.0.0.0/8 to assigned 80-80",
+				gateStatus: ie.GateStatusClosed,
+			},
+		},
+		{name: "incorrect app filter bad protocol",
+			args: &args{
+				filterString: "test:10.0.0.0/8:80-80:allow",
+			},
+			want:    &want{},
+			wantErr: true,
+		},
+		{name: "incorrect app filter bad IP format",
+			args: &args{
+				filterString: "ip:10/8:80-80:allow",
+			},
+			want:    &want{},
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(
+			tt.name, func(t *testing.T) {
+				filter, gateStatus, err := parseAppFilter(tt.args.filterString)
+				if tt.wantErr {
+					require.Error(t, err)
+					return
+				}
+
+				require.Equal(t, tt.want.SDFFilter, filter)
+				require.Equal(t, tt.want.gateStatus, gateStatus)
+			},
+		)
+	}
+}

internal/pfcpsim/server.go

@@ -127,18 +127,19 @@ func (P pfcpSimService) CreateSession(ctx context.Context, request *pb.CreateSes
 	var SDFFilter = ""
 	var qfi, gateStatus uint8 = 0, ieLib.GateStatusOpen
 
-	if request.GateClosed {
-		gateStatus = ieLib.GateStatusClosed
+	if request.AppFilter != "" {
+		SDFFilter, gateStatus, err = parseAppFilter(request.AppFilter)
+		if err != nil {
+			return &pb.Response{}, status.Error(codes.Aborted, err.Error())
+		}
+
+		log.Infof("Successfully parsed application filter. SDF Filter: %v", SDFFilter)
 	}
 
 	if request.Qfi != 0 {
 		qfi = uint8(request.Qfi)
 	}
 
-	if request.SdfFilter != "" {
-		SDFFilter = request.SdfFilter
-	}
-
 	for i := baseID; i < (count*2 + baseID); i = i + 2 {
 		// using variables to ease comprehension on how rules are linked together
 		uplinkTEID := uint32(i)
@@ -150,7 +151,7 @@ func (P pfcpSimService) CreateSession(ctx context.Context, request *pb.CreateSes
 		downlinkFarID := uint32(i + 1)
 
 		uplinkPdrID := uint16(i)
-		dowlinkPdrID := uint16(i + 1)
+		downlinkPdrID := uint16(i + 1)
 
 		sessQerID := uint32(i + 3)
 
@@ -174,7 +175,7 @@ func (P pfcpSimService) CreateSession(ctx context.Context, request *pb.CreateSes
 
 			// DownlinkPDR
 			session.NewPDRBuilder().
-				WithID(dowlinkPdrID).
+				WithID(downlinkPdrID).
 				WithMethod(session.Create).
 				WithPrecedence(100).
 				WithUEAddress(ueAddress.String()).

pkg/pfcpsim/errors.go

@@ -42,6 +42,13 @@ func NewNotEnoughSessionsError(err ...error) *pfcpSimError {
 	}
 }
 
+func NewInvalidFormatError(what string, err ...error) *pfcpSimError {
+	return &pfcpSimError{
+		message: fmt.Sprintf("Invalid format: %v", what),
+		error:   err,
+	}
+}
+
 func NewNoValidInterfaceError(err ...error) *pfcpSimError {
 	return &pfcpSimError{
 		message: "No valid interface found",