Support skip_hw/skip_sw flags

This feature could not be tested with virtual interfaces that's why
unit-tests aren't added into this change.

filter_linux.go

@@ -64,6 +64,8 @@ type Flower struct {
 	EncSrcIPMask  net.IPMask
 	EncDestPort   uint16
 	EncKeyId      uint32
+	SkipHw        bool
+	SkipSw        bool
 
 	Actions []Action
 }
@@ -130,6 +132,15 @@ func (filter *Flower) encode(parent *nl.RtAttr) error {
 		parent.AddRtAttr(nl.TCA_FLOWER_KEY_ENC_KEY_ID, htonl(filter.EncKeyId))
 	}
 
+	var flags uint32 = 0
+	if filter.SkipHw {
+		flags |= nl.TCA_CLS_FLAGS_SKIP_HW
+	}
+	if filter.SkipSw {
+		flags |= nl.TCA_CLS_FLAGS_SKIP_SW
+	}
+	parent.AddRtAttr(nl.TCA_FLOWER_FLAGS, htonl(flags))
+
 	actionsAttr := parent.AddRtAttr(nl.TCA_FLOWER_ACT, nil)
 	if err := EncodeActions(actionsAttr, filter.Actions); err != nil {
 		return err
@@ -171,6 +182,16 @@ func (filter *Flower) decode(data []syscall.NetlinkRouteAttr) error {
 			if err != nil {
 				return err
 			}
+		case nl.TCA_FLOWER_FLAGS:
+			attr := nl.DeserializeUint32Bitfield(datum.Value)
+			skipSw := attr.Value & nl.TCA_CLS_FLAGS_SKIP_HW
+			skipHw := attr.Value & nl.TCA_CLS_FLAGS_SKIP_SW
+			if skipSw != 0 {
+				filter.SkipSw = true
+			}
+			if skipHw != 0 {
+				filter.SkipHw = true
+			}
 		}
 	}
 	return nil
@@ -344,7 +365,6 @@ func (h *Handle) filterModify(filter Filter, flags int) error {
 			return err
 		}
 	}
-
 	req.AddData(options)
 	_, err := req.Execute(unix.NETLINK_ROUTE, 0)
 	return err

filter_test.go

@@ -1850,7 +1850,6 @@ func TestFilterFlowerAddDel(t *testing.T) {
 	if filter.EncDestPort != flower.EncDestPort {
 		t.Fatalf("Flower EncDestPort doesn't match")
 	}
-
 	mia, ok := flower.Actions[0].(*MirredAction)
 	if !ok {
 		t.Fatal("Unable to find mirred action")

nl/nl_linux.go

@@ -330,6 +330,19 @@ func NewIfInfomsgChild(parent *RtAttr, family int) *IfInfomsg {
 	return msg
 }
 
+type Uint32Bitfield struct {
+	Value    uint32
+	Selector uint32
+}
+
+func (a *Uint32Bitfield) Serialize() []byte {
+	return (*(*[SizeofUint32Bitfield]byte)(unsafe.Pointer(a)))[:]
+}
+
+func DeserializeUint32Bitfield(data []byte) *Uint32Bitfield {
+	return (*Uint32Bitfield)(unsafe.Pointer(&data[0:SizeofUint32Bitfield][0]))
+}
+
 type Uint32Attribute struct {
 	Type  uint16
 	Value uint32

nl/tc_linux.go

@@ -63,6 +63,12 @@ const (
 	TCA_ACT_OPTIONS
 	TCA_ACT_INDEX
 	TCA_ACT_STATS
+	TCA_ACT_PAD
+	TCA_ACT_COOKIE
+	TCA_ACT_FLAGS
+	TCA_ACT_HW_STATS
+	TCA_ACT_USED_HW_STATS
+	TCA_ACT_IN_HW_COUNT
 	TCA_ACT_MAX
 )
 
@@ -105,6 +111,7 @@ const (
 	SizeofTcSfqQopt      = 0x0b
 	SizeofTcSfqRedStats  = 0x18
 	SizeofTcSfqQoptV1    = SizeofTcSfqQopt + SizeofTcSfqRedStats + 0x1c
+	SizeofUint32Bitfield = 0x8
 )
 
 // struct tcmsg {
@@ -1030,6 +1037,9 @@ const (
 	__TCA_FLOWER_MAX
 )
 
+const TCA_CLS_FLAGS_SKIP_HW = 1 << 0 /* don't offload filter to HW */
+const TCA_CLS_FLAGS_SKIP_SW = 1 << 1 /* don't use filter in SW */
+
 // struct tc_sfq_qopt {
 // 	unsigned	quantum;	/* Bytes per round allocated to flow */
 // 	int		perturb_period;	/* Period of hash perturbation */