add ARP operation field to the list of fields that OVS can match on

Author: Fouad Hallal

ovs/match.go

@@ -35,6 +35,7 @@ const (
 
 // Constants of full Match names.
 const (
+	arpOp    = "arp_op"
 	arpSHA   = "arp_sha"
 	arpSPA   = "arp_spa"
 	arpTHA   = "arp_tha"
@@ -433,6 +434,30 @@ func (m *neighborDiscoveryLinkLayerMatch) GoString() string {
 	return fmt.Sprintf("ovs.NeighborDiscoveryTargetLinkLayer(%s)", syntax)
 }
 
+//  ARPOperation matches packets with the specified ARP operation matching oper.
+func ARPOperation(oper uint16) Match {
+	return &arpOperationMatch{
+		oper: oper,
+	}
+}
+
+var _ Match = &arpOperationMatch{}
+
+// An arpOperationMatch is a Match returned by ARPOperation.
+type arpOperationMatch struct {
+	oper uint16
+}
+
+// MarshalText implements Match.
+func (m *arpOperationMatch) MarshalText() ([]byte, error) {
+	return bprintf("%s=%d", arpOp, m.oper), nil
+}
+
+// GoString implements Match.
+func (m *arpOperationMatch) GoString() string {
+	return fmt.Sprintf("ovs.ARPOperation(%d)", m.oper)
+}
+
 // ARPSourceHardwareAddress matches packets with an ARP source hardware address
 // (SHA) matching addr.
 func ARPSourceHardwareAddress(addr net.HardwareAddr) Match {

ovs/match_test.go

@@ -1035,6 +1035,10 @@ func TestMatchGoString(t *testing.T) {
 			m: ConjunctionID(123),
 			s: `ovs.ConjunctionID(123)`,
 		},
+		{
+			m: ARPOperation(2),
+			s: `ovs.ARPOperation(2)`,
+		},
 	}
 
 	for _, tt := range tests {
@@ -1046,6 +1050,39 @@ func TestMatchGoString(t *testing.T) {
 	}
 }
 
+func TestMatchARPOperation(t *testing.T) {
+	var tests = []struct {
+		desc string
+		oper uint16
+		out  string
+	}{
+		{
+			desc: "request",
+			oper: 1,
+			out:  "arp_op=1",
+		},
+		{
+			desc: "response",
+			oper: 2,
+			out:  "arp_op=2",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			out, err := ARPOperation(tt.oper).MarshalText()
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+
+			if want, got := tt.out, string(out); want != got {
+				t.Fatalf("unexpected Match output:\n- want: %q\n-  got: %q",
+					want, got)
+			}
+		})
+	}
+}
+
 // mustParseMAC is a helper to parse a hardware address from a string using
 // net.ParseMAC, that panic on failure.
 func mustParseMAC(addr string) net.HardwareAddr {