Add Clsact qdisc

Straight copy from jrfastab's fork, but applied to newer main.

Signed-off-by: Kevin Sheldrake <kevin.sheldrake@isovalent.com>

filter_test.go

@@ -1055,14 +1055,12 @@ func setupLinkForTestWithQdisc(t *testing.T, linkName string) (Qdisc, Link) {
 	if err := LinkSetUp(link); err != nil {
 		t.Fatal(err)
 	}
-	attrs := QdiscAttrs{
-		LinkIndex: link.Attrs().Index,
-		Handle:    MakeHandle(0xffff, 0),
-		Parent:    HANDLE_CLSACT,
-	}
-	qdisc := &GenericQdisc{
-		QdiscAttrs: attrs,
-		QdiscType:  "clsact",
+	qdisc := &Clsact{
+		QdiscAttrs: QdiscAttrs{
+			LinkIndex: link.Attrs().Index,
+			Handle:    MakeHandle(0xffff, 0),
+			Parent:    HANDLE_CLSACT,
+		},
 	}
 
 	if err := QdiscAdd(qdisc); err != nil {
@@ -1075,7 +1073,7 @@ func setupLinkForTestWithQdisc(t *testing.T, linkName string) (Qdisc, Link) {
 	if len(qdiscs) != 1 {
 		t.Fatal("Failed to add qdisc", len(qdiscs))
 	}
-	if q, ok := qdiscs[0].(*GenericQdisc); !ok || q.Type() != "clsact" {
+	if q, ok := qdiscs[0].(*Clsact); !ok || q.Type() != "clsact" {
 		t.Fatal("qdisc is the wrong type")
 	}
 	return qdiscs[0], link

qdisc.go

@@ -217,6 +217,19 @@ func (qdisc *Tbf) Type() string {
 	return "tbf"
 }
 
+// Clsact is a qdisc for adding filters
+type Clsact struct {
+	QdiscAttrs
+}
+
+func (qdisc *Clsact) Attrs() *QdiscAttrs {
+	return &qdisc.QdiscAttrs
+}
+
+func (qdisc *Clsact) Type() string {
+	return "clsact"
+}
+
 // Ingress is a qdisc for adding ingress filters
 type Ingress struct {
 	QdiscAttrs

qdisc_linux.go

@@ -234,6 +234,8 @@ func qdiscPayload(req *nl.NetlinkRequest, qdisc Qdisc) error {
 		if reorder.Probability > 0 {
 			options.AddRtAttr(nl.TCA_NETEM_REORDER, reorder.Serialize())
 		}
+	case *Clsact:
+		options = nil
 	case *Ingress:
 		// ingress filters must use the proper handle
 		if qdisc.Attrs().Parent != HANDLE_INGRESS {
@@ -392,6 +394,8 @@ func (h *Handle) QdiscList(link Link) ([]Qdisc, error) {
 					qdisc = &Netem{}
 				case "sfq":
 					qdisc = &Sfq{}
+				case "clsact":
+					qdisc = &Clsact{}
 				default:
 					qdisc = &GenericQdisc{QdiscType: qdiscType}
 				}