Change default max_len to 65535 for controller action (contiv#69)

Instead of 128. 65535 means that there is no buffering and that the full packet is sent to the controller. This is actually the only value supported by OVS, even though OVS will not reject other values. This can create confusion as the flows will show `max_len=128`, but the controller will always receive the full packet. Another value for max_len can be explicitly provided using the new `MaxLen` field in the `NXController` struct, but there should be no reason to do so when using OVS. See openvswitch/ovs-issues#295 Signed-off-by: Antonin Bas <[email protected]>
wenyingd · Aug 16, 2023 · a9c0ea7 · a9c0ea7
1 parent 988fe7f
commit a9c0ea7
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Showing 3 changed files with 12 additions and 4 deletions.
diff --git a/VERSION b/VERSION
@@ -1 +1 @@
-v0.9.0
+v0.10.0
diff --git a/ofctrl/ofAction.go b/ofctrl/ofAction.go
@@ -657,21 +657,29 @@ type NXController struct {
 	UserData     []byte
 	MeterID      uint32
 	Pause        bool
+	MaxLen       *uint16
 }
 
 func (a *NXController) GetActionMessage() openflow15.Action {
+	// By default, do not buffer, i.e., send the full packet to the controller.
+	// Note that OVS does not support buffering and always sends the full
+	// packet; it will ignore other values of max_len.
+	maxLen := uint16(openflow15.OFPCML_NO_BUFFER)
+	if a.MaxLen != nil {
+		maxLen = *a.MaxLen
+	}
 	if a.Version2 {
 		action := openflow15.NewNXActionController2()
 		action.AddControllerID(a.ControllerID)
 		action.AddReason(a.Reason)
 		action.AddUserdata(a.UserData)
-		action.AddMaxLen(128)
+		action.AddMaxLen(maxLen)
 		action.AddMeterID(a.MeterID)
 		action.AddPause(a.Pause)
 		return action
 	}
 	action := openflow15.NewNXActionController(a.ControllerID)
-	action.MaxLen = 128
+	action.MaxLen = maxLen
 	action.Reason = a.Reason
 	return action
 }

diff --git a/ofctrl/ofpacket_test.go b/ofctrl/ofpacket_test.go
@@ -148,7 +148,7 @@ func TestNxOutputAndSendController(t *testing.T) {
 	flow1.Send(openflow15.FC_ADD)
 	verifyFlowInstallAndDelete(t, flow1, NewEmptyElem(), brName, table0.TableId,
 		"priority=100,ip,dl_src=11:22:33:44:55:66",
-		fmt.Sprintf("output:NXM_NX_REG0[],controller(max_len=128,id=%d)", app.Switch.ctrlID))
+		fmt.Sprintf("output:NXM_NX_REG0[],controller(id=%d)", app.Switch.ctrlID))
 }
 
 func testPacketInOut(t *testing.T, ofApp *packetApp, ipv6 bool, reason uint8, controllerV2 bool, dstPort uint16, userData []byte, pause bool) {