ovs: add conjunction action

Author: icosahedral

ovs/action.go

@@ -45,6 +45,10 @@ var (
 	// errResubmitPortInvalid is returned when ResubmitPort is given a port number that is
 	// invalid per the openflow spec.
 	errResubmitPortInvalid = errors.New("resubmit port must be between 0 and 65279 inclusive")
+
+	// errTooManyDimensions is returned when the specified dimension exceeds the total dimension
+	// in a conjunction action.
+	errDimensionTooLarge = errors.New("dimension number exceeds total number of dimensions")
 )
 
 // Action strings in lower case, as those are compared to the lower case letters
@@ -145,6 +149,7 @@ func StripVLAN() Action {
 // printf-style patterns for marshaling and unmarshaling actions.
 const (
 	patConnectionTracking          = "ct(%s)"
+	patConjunction                 = "conjunction(%d, %d/%d)"
 	patModDataLinkDestination      = "mod_dl_dst:%s"
 	patModDataLinkSource           = "mod_dl_src:%s"
 	patModNetworkDestination       = "mod_nw_dst:%s"
@@ -372,6 +377,37 @@ func (a *outputAction) GoString() string {
 	return fmt.Sprintf("ovs.Output(%d)", a.port)
 }
 
+// Conjunction associates a flow with a certain conjunction ID to match on more than
+// one dimension across multiple set matches.
+func Conjunction(id int, dimensionNumber int, dimensionSize int) Action {
+	return &conjunctionAction{
+		id:              id,
+		dimensionNumber: dimensionNumber,
+		dimensionSize:   dimensionSize,
+	}
+}
+
+// A conjuctionAction is an Action which is used by Conjunction.
+type conjunctionAction struct {
+	id              int
+	dimensionNumber int
+	dimensionSize   int
+}
+
+// MarshalText implements Action.
+func (a *conjunctionAction) MarshalText() ([]byte, error) {
+	if a.dimensionNumber > a.dimensionSize {
+		return nil, errDimensionTooLarge
+	}
+
+	return bprintf(patConjunction, a.id, a.dimensionNumber, a.dimensionSize), nil
+}
+
+// GoString implements Action.
+func (a *conjunctionAction) GoString() string {
+	return fmt.Sprintf("ovs.Conjunction(%d, %d, %d)", a.id, a.dimensionNumber, a.dimensionSize)
+}
+
 // Resubmit resubmits a packet for further processing by matching
 // flows with the specified port and table.  If port or table are zero,
 // they are set to empty in the output Action.  If both are zero, an

ovs/action_test.go

@@ -531,6 +531,50 @@ func TestSetTunnel(t *testing.T) {
 	}
 }
 
+func TestConjunction(t *testing.T) {
+	var tests = []struct {
+		desc   string
+		a      Action
+		action string
+		err    error
+	}{
+		{
+			desc:   "set conjunction 1/2",
+			a:      Conjunction(123, 1, 2),
+			action: "conjunction(123, 1/2)",
+		},
+		{
+			desc:   "set conjunction 2/2",
+			a:      Conjunction(123, 2, 2),
+			action: "conjunction(123, 2/2)",
+		},
+		{
+			desc: "set conjunction 3/2",
+			a:    Conjunction(123, 3, 2),
+			err:  errDimensionTooLarge,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			action, err := tt.a.MarshalText()
+
+			if want, got := tt.err, err; want != got {
+				t.Fatalf("unexpected error:\n- want: %v\n-  got: %v",
+					want, got)
+			}
+			if err != nil {
+				return
+			}
+
+			if want, got := tt.action, string(action); want != got {
+				t.Fatalf("unexpected Action:\n- want: %q\n-  got: %q",
+					want, got)
+			}
+		})
+	}
+}
+
 func TestActionGoString(t *testing.T) {
 	tests := []struct {
 		a Action
@@ -600,6 +644,10 @@ func TestActionGoString(t *testing.T) {
 			a: SetTunnel(10),
 			s: `ovs.SetTunnel(0xa)`,
 		},
+		{
+			a: Conjunction(123, 1, 2),
+			s: `ovs.Conjunction(123, 1, 2)`,
+		},
 	}
 
 	for _, tt := range tests {

ovs/actionparser.go

@@ -297,6 +297,18 @@ func parseAction(s string) (Action, error) {
 		}
 	}
 
+	// ActionConjunction, with it's id, dimension number, and dimension size
+	if strings.HasPrefix(s, patConjunction[:len(patConjunction)-10]) {
+		var id, dimensionNumber, dimensionSize int
+		n, err := fmt.Sscanf(s, patConjunction, &id, &dimensionNumber, &dimensionSize)
+		if err != nil {
+			return nil, err
+		}
+		if n > 0 {
+			return Conjunction(id, dimensionNumber, dimensionSize), nil
+		}
+	}
+
 	// ActionOutput, with its port number
 	if strings.HasPrefix(s, patOutput[:len(patOutput)-2]) {
 		var port int

ovs/actionparser_test.go

@@ -281,6 +281,22 @@ func Test_parseAction(t *testing.T) {
 			s: "set_field:192.168.1.1->arp_spa",
 			a: SetField("192.168.1.1", "arp_spa"),
 		},
+		{
+			s: "conjunction(123, 1/2)",
+			a: Conjunction(123, 1, 2),
+		},
+		{
+			s: "conjunction(123, 2/2)",
+			a: Conjunction(123, 2, 2),
+		},
+		{
+			s:       "conjunction(123, 3/2)",
+			invalid: true,
+		},
+		{
+			s:       "conjunxxxxx(123, 3/2)",
+			invalid: true,
+		},
 	}
 
 	for _, tt := range tests {