From a9c0ea7a91d95d8fbb827ccacf8bd5c59dd70d2f Mon Sep 17 00:00:00 2001
From: Antonin Bas <abas@vmware.com>
Date: Wed, 16 Aug 2023 10:57:47 -0700
Subject: [PATCH] Change default max_len to 65535 for controller action (#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 https://github.com/openvswitch/ovs-issues/issues/295

Signed-off-by: Antonin Bas <abas@vmware.com>
---
 VERSION                 |  2 +-
 ofctrl/ofAction.go      | 12 ++++++++++--
 ofctrl/ofpacket_test.go |  2 +-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/VERSION b/VERSION
index f979adec..bf057dbf 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-v0.9.0
+v0.10.0
diff --git a/ofctrl/ofAction.go b/ofctrl/ofAction.go
index a075b4bc..b81bc3b7 100644
--- 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
index 311e236d..7e5832c3 100644
--- 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) {