add m_skbmod

Signed-off-by: Florian Lehner <dev@der-flo.net>

m_action.go

@@ -74,6 +74,7 @@ type Action struct {
 	TunnelKey *TunnelKey
 	MPLS      *MPLS
 	SkbEdit   *SkbEdit
+	SkbMod    *SkbMod
 }
 
 func unmarshalActions(data []byte, actions *[]*Action) error {
@@ -243,6 +244,10 @@ func marshalAction(cmd int, info *Action, actOption uint16) ([]byte, error) {
 		data, err := marshalSkbEdit(info.SkbEdit)
 		multiError = concatError(multiError, err)
 		options = append(options, tcOption{Interpretation: vtBytes, Type: actOption, Data: data})
+	case "skbmod":
+		data, err := marshalSkbMod(info.SkbMod)
+		multiError = concatError(multiError, err)
+		options = append(options, tcOption{Interpretation: vtBytes, Type: actOption, Data: data})
 	default:
 		return []byte{}, fmt.Errorf("unknown kind '%s'", info.Kind)
 	}
@@ -362,6 +367,11 @@ func extractActOptions(data []byte, act *Action, kind string) error {
 		err = unmarshalSkbEdit(data, info)
 		multiError = concatError(multiError, err)
 		act.SkbEdit = info
+	case "skbmod":
+		info := &SkbMod{}
+		err = unmarshalSkbMod(data, info)
+		multiError = concatError(multiError, err)
+		act.SkbMod = info
 	default:
 		return fmt.Errorf("extractActOptions(): unsupported kind: %s", kind)
 

m_action_test.go

@@ -103,6 +103,10 @@ func TestAction(t *testing.T) {
 			Kind:    "skbedit",
 			SkbEdit: &SkbEdit{Priority: uint32Ptr(42)},
 		}},
+		"skbmod": {val: Action{
+			Kind:   "skbmod",
+			SkbMod: &SkbMod{EType: uint16Ptr(73)},
+		}},
 	}
 
 	for name, testcase := range tests {

m_skbmod.go

@@ -0,0 +1,102 @@
+package tc
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/mdlayher/netlink"
+)
+
+const (
+	tcaSkbModUnspec = iota
+	tcaSkbModTm
+	tcaSkbModParms
+	tcaSkbModDMac
+	tcaSkbModSMac
+	tcaSkbModEType
+	tcaSkbModPad
+)
+
+// SkbMod contains attribute of thet SkbMod discipline
+type SkbMod struct {
+	Tm    *Tcft
+	Parms *SkbModParms
+	DMac  *net.HardwareAddr
+	SMac  *net.HardwareAddr
+	EType *uint16
+}
+
+// SkbModParms from include/uapi/linux/tc_act/tc_skbmod.h
+type SkbModParms struct {
+	Index   uint32
+	Capab   uint32
+	Action  uint32
+	RefCnt  uint32
+	BindCnt uint32
+	Flags   uint64
+}
+
+func marshalSkbMod(info *SkbMod) ([]byte, error) {
+	options := []tcOption{}
+	if info == nil {
+		return []byte{}, fmt.Errorf("skbmod: %w", ErrNoArg)
+	}
+	// TODO: improve logic and check combinations
+	if info.Tm != nil {
+		return []byte{}, ErrNoArgAlter
+	}
+
+	if info.Parms != nil {
+		data, err := marshalStruct(info.Parms)
+		if err != nil {
+			return []byte{}, err
+		}
+		options = append(options, tcOption{Interpretation: vtBytes, Type: tcaSkbModParms, Data: data})
+	}
+	if info.DMac != nil {
+		options = append(options, tcOption{Interpretation: vtBytes, Type: tcaSkbModDMac, Data: hardwareAddrToBytes(*info.DMac)})
+	}
+	if info.SMac != nil {
+		options = append(options, tcOption{Interpretation: vtBytes, Type: tcaSkbModSMac, Data: hardwareAddrToBytes(*info.SMac)})
+	}
+	if info.EType != nil {
+		options = append(options, tcOption{Interpretation: vtUint16, Type: tcaSkbModEType, Data: *info.EType})
+	}
+
+	return marshalAttributes(options)
+}
+
+func unmarshalSkbMod(data []byte, info *SkbMod) error {
+	ad, err := netlink.NewAttributeDecoder(data)
+	if err != nil {
+		return err
+	}
+	var multiError error
+	for ad.Next() {
+		switch ad.Type() {
+		case tcaSkbModParms:
+			parms := &SkbModParms{}
+			err = unmarshalStruct(ad.Bytes(), parms)
+			multiError = concatError(multiError, err)
+			info.Parms = parms
+		case tcaSkbModTm:
+			tcft := &Tcft{}
+			err = unmarshalStruct(ad.Bytes(), tcft)
+			multiError = concatError(multiError, err)
+			info.Tm = tcft
+		case tcaSkbModDMac:
+			mac := bytesToHardwareAddr(ad.Bytes())
+			info.DMac = &mac
+		case tcaSkbModSMac:
+			mac := bytesToHardwareAddr(ad.Bytes())
+			info.SMac = &mac
+		case tcaSkbModEType:
+			info.EType = uint16Ptr(ad.Uint16())
+		case tcaSkbModPad:
+			// padding does not contain data, we just skip it
+		default:
+			return fmt.Errorf("unmarshalSkbMod()\t%d\n\t%v", ad.Type(), ad.Bytes())
+		}
+	}
+	return concatError(multiError, ad.Err())
+}

m_skbmod_test.go

@@ -0,0 +1,59 @@
+package tc
+
+import (
+	"errors"
+	"net"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestSkbMod(t *testing.T) {
+	srcMac, _ := net.ParseMAC("00:00:5e:00:53:01")
+	dstMac, _ := net.ParseMAC("00:00:5e:00:53:02")
+	tests := map[string]struct {
+		val  SkbMod
+		err1 error
+		err2 error
+	}{
+		"simple": {val: SkbMod{
+			Parms: &SkbModParms{Index: 42},
+			SMac:  &srcMac,
+			DMac:  &dstMac,
+			EType: uint16Ptr(13)}},
+	}
+
+	for name, testcase := range tests {
+		t.Run(name, func(t *testing.T) {
+			data, err1 := marshalSkbMod(&testcase.val)
+			if err1 != nil {
+				if errors.Is(err1, testcase.err1) {
+					return
+				}
+				t.Fatalf("Unexpected error: %v", err1)
+			}
+
+			newData, tm := injectTcft(t, data, tcaSkbModTm)
+			newData = injectAttribute(t, newData, []byte{}, tcaSkbModPad)
+			val := SkbMod{}
+			err2 := unmarshalSkbMod(newData, &val)
+			if err2 != nil {
+				if errors.Is(err2, testcase.err2) {
+					return
+				}
+				t.Fatalf("Unexpected error: %v", err2)
+
+			}
+			testcase.val.Tm = tm
+			if diff := cmp.Diff(val, testcase.val); diff != "" {
+				t.Fatalf("Defact missmatch (want +got):\n%s", diff)
+			}
+		})
+	}
+	t.Run("nil", func(t *testing.T) {
+		_, err := marshalSkbMod(nil)
+		if !errors.Is(err, ErrNoArg) {
+			t.Fatalf("unexpected error: %v", err)
+		}
+	})
+}