Add Hash to U32

This patch adds "Hash" attribute that represents the ID of the hash
table with which the filter is associated to U32 struct. If the hash
table is not created yet, a new hash table is created with the
specified ID.

Signed-off-by: Taku Fukushima <taku@soracom.jp>

filter.go

@@ -213,6 +213,7 @@ type U32 struct {
 	FilterAttrs
 	ClassId    uint32
 	Divisor    uint32 // Divisor MUST be power of 2.
+	Hash       uint32
 	RedirIndex int
 	Sel        *TcU32Sel
 	Actions    []Action

filter_linux.go

@@ -178,6 +178,9 @@ func (h *Handle) FilterAdd(filter Filter) error {
 			}
 			nl.NewRtAttrChild(options, nl.TCA_U32_DIVISOR, nl.Uint32Attr(filter.Divisor))
 		}
+		if filter.Hash != 0 {
+			nl.NewRtAttrChild(options, nl.TCA_U32_HASH, nl.Uint32Attr(filter.Hash))
+		}
 		actionsAttr := nl.NewRtAttrChild(options, nl.TCA_U32_ACT, nil)
 		// backwards compatibility
 		if filter.RedirIndex != 0 {
@@ -508,6 +511,8 @@ func parseU32Data(filter Filter, data []syscall.NetlinkRouteAttr) (bool, error)
 			u32.ClassId = native.Uint32(datum.Value)
 		case nl.TCA_U32_DIVISOR:
 			u32.Divisor = native.Uint32(datum.Value)
+		case nl.TCA_U32_HASH:
+			u32.Hash = native.Uint32(datum.Value)
 		}
 	}
 	return detailed, nil

filter_test.go

@@ -202,9 +202,12 @@ func TestAdvancedFilterAddDel(t *testing.T) {
 			OffMask: 0,
 		},
 	}
+
+	handle := MakeHandle(0x0000, 0001)
 	filter := &U32{
 		FilterAttrs: FilterAttrs{
 			LinkIndex: index,
+			Handle:    handle,
 			Parent:    qdiscHandle,
 			Priority:  1,
 			Protocol:  unix.ETH_P_ALL,
@@ -214,6 +217,7 @@ func TestAdvancedFilterAddDel(t *testing.T) {
 			Flags: TC_U32_TERMINAL,
 		},
 		ClassId: classId,
+		Hash:    htid,
 		Actions: []Action{},
 	}
 	// Copy filter.
@@ -253,8 +257,15 @@ func TestAdvancedFilterAddDel(t *testing.T) {
 			t.Fatal("The endianness of TcU32Key.Val is wrong")
 		}
 	}
+	if u32.Handle != (handle | htid) {
+		t.Fatalf("The handle is wrong. expected %v but actually %v",
+			(handle | htid), u32.Handle)
+	}
+	if u32.Hash != htid {
+		t.Fatal("The hash table ID is wrong")
+	}
 
-	if err := FilterDel(filter); err != nil {
+	if err := FilterDel(u32); err != nil {
 		t.Fatal(err)
 	}
 	filters, err = FilterList(link, qdiscHandle)