Adding DelRule and unit tests (#36)

Signed-off-by: Serguei Bezverkhi <sbezverk@cisco.com>

nftables_test.go

@@ -561,6 +561,51 @@ func TestAddCounter(t *testing.T) {
 	}
 }
 
+func TestDelRule(t *testing.T) {
+	want := [][]byte{
+		// batch begin
+		[]byte("\x00\x00\x00\x0a"),
+		// nft delete rule ipv4table ipv4chain-1 handle 9
+		[]byte("\x02\x00\x00\x00\x0e\x00\x01\x00\x69\x70\x76\x34\x74\x61\x62\x6c\x65\x00\x00\x00\x10\x00\x02\x00\x69\x70\x76\x34\x63\x68\x61\x69\x6e\x2d\x31\x00\x0c\x00\x03\x00\x00\x00\x00\x00\x00\x00\x00\x09"),
+		// batch end
+		[]byte("\x00\x00\x00\x0a"),
+	}
+
+	c := &nftables.Conn{
+		TestDial: func(req []netlink.Message) ([]netlink.Message, error) {
+			for idx, msg := range req {
+				b, err := msg.MarshalBinary()
+				if err != nil {
+					t.Fatal(err)
+				}
+				if len(b) < 16 {
+					continue
+				}
+				b = b[16:]
+				if len(want) == 0 {
+					t.Errorf("no want entry for message %d: %x", idx, b)
+					continue
+				}
+				if got, want := b, want[0]; !bytes.Equal(got, want) {
+					t.Errorf("message %d: %s", idx, linediff(nfdump(got), nfdump(want)))
+				}
+				want = want[1:]
+			}
+			return req, nil
+		},
+	}
+
+	c.DelRule(&nftables.Rule{
+		Table:  &nftables.Table{Name: "ipv4table", Family: nftables.TableFamilyIPv4},
+		Chain:  &nftables.Chain{Name: "ipv4chain-1", Type: nftables.ChainTypeFilter},
+		Handle: uint64(9),
+	})
+
+	if err := c.Flush(); err != nil {
+		t.Fatal(err)
+	}
+}
+
 func TestTProxy(t *testing.T) {
 	want := [][]byte{
 		// batch begin

rule.go

@@ -170,6 +170,31 @@ func (cc *Conn) AddRule(r *Rule) *Rule {
 	return r
 }
 
+// DelRule deletes the specified Rule, rule's handle cannot be 0
+func (cc *Conn) DelRule(r *Rule) error {
+	data := cc.marshalAttr([]netlink.Attribute{
+		{Type: unix.NFTA_RULE_TABLE, Data: []byte(r.Table.Name + "\x00")},
+		{Type: unix.NFTA_RULE_CHAIN, Data: []byte(r.Chain.Name + "\x00")},
+	})
+	if r.Handle == 0 {
+		return fmt.Errorf("rule's handle cannot be 0")
+	}
+	data = append(data, cc.marshalAttr([]netlink.Attribute{
+		{Type: unix.NFTA_RULE_HANDLE, Data: binaryutil.BigEndian.PutUint64(r.Handle)},
+	})...)
+	flags := netlink.Request | netlink.Acknowledge
+
+	cc.messages = append(cc.messages, netlink.Message{
+		Header: netlink.Header{
+			Type:  netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | unix.NFT_MSG_DELRULE),
+			Flags: flags,
+		},
+		Data: append(extraHeader(uint8(r.Table.Family), 0), data...),
+	})
+
+	return nil
+}
+
 func exprsFromMsg(b []byte) ([]expr.Any, error) {
 	ad, err := netlink.NewAttributeDecoder(b)
 	if err != nil {