TUN-9883: Add new datagram v3 feature flag

After the previous rollout was reverted, the original `support_datagram_v3_1` is deprecated and replaced with
`support_datagram_v3_2`.

Closes TUN-9883

client/config_test.go

@@ -45,6 +45,6 @@ func (m *mockFeatureSelector) Snapshot() features.FeatureSnapshot {
 	return features.FeatureSnapshot{
 		PostQuantum:     features.PostQuantumPrefer,
 		DatagramVersion: features.DatagramV3,
-		FeaturesList:    []string{features.FeaturePostQuantum, features.FeatureDatagramV3_1},
+		FeaturesList:    []string{features.FeaturePostQuantum, features.FeatureDatagramV3_2},
 	}
 }

features/features.go

@@ -10,9 +10,10 @@ const (
 	FeaturePostQuantum       = "postquantum"
 	FeatureQUICSupportEOF    = "support_quic_eof"
 	FeatureManagementLogs    = "management_logs"
-	FeatureDatagramV3_1      = "support_datagram_v3_1"
+	FeatureDatagramV3_2      = "support_datagram_v3_2"
 
 	DeprecatedFeatureDatagramV3   = "support_datagram_v3"   // Deprecated: TUN-9291
+	DeprecatedFeatureDatagramV3_1 = "support_datagram_v3_1" // Deprecated: TUN-9883
 )
 
 var defaultFeatures = []string{
@@ -26,6 +27,7 @@ var defaultFeatures = []string{
 // List of features that are no longer in-use.
 var deprecatedFeatures = []string{
 	DeprecatedFeatureDatagramV3,
+	DeprecatedFeatureDatagramV3_1,
 }
 
 // Features set by user provided flags
@@ -58,7 +60,7 @@ const (
 	// DatagramV2 is the currently supported datagram protocol for UDP and ICMP packets
 	DatagramV2 DatagramVersion = FeatureDatagramV2
 	// DatagramV3 is a new datagram protocol for UDP and ICMP packets. It is not backwards compatible with datagram v2.
-	DatagramV3 DatagramVersion = FeatureDatagramV3_1
+	DatagramV3 DatagramVersion = FeatureDatagramV3_2
 )
 
 // Remove any duplicate features from the list and remove deprecated features

features/selector.go

@@ -23,9 +23,10 @@ const (
 // If the TXT record is missing a key, the field will unmarshal to the default Go value
 
 type featuresRecord struct {
-	DatagramV3Percentage uint32 `json:"dv3_1"`
+	DatagramV3Percentage uint32 `json:"dv3_2"`
 
 	// DatagramV3Percentage int32 `json:"dv3"` // Removed in TUN-9291
+	// DatagramV3Percentage uint32 `json:"dv3_1"` // Removed in TUN-9883
 	// PostQuantumPercentage int32 `json:"pq"` // Removed in TUN-7970
 }
 
@@ -105,7 +106,7 @@ func (fs *featureSelector) postQuantumMode() PostQuantumMode {
 
 func (fs *featureSelector) datagramVersion() DatagramVersion {
 	// If user provides the feature via the cli, we take it as priority over remote feature evaluation
-	if slices.Contains(fs.cliFeatures, FeatureDatagramV3_1) {
+	if slices.Contains(fs.cliFeatures, FeatureDatagramV3_2) {
 		return DatagramV3
 	}
 	// If the user specifies DatagramV2, we also take that over remote

features/selector_test.go

@@ -22,15 +22,15 @@ func TestUnmarshalFeaturesRecord(t *testing.T) {
 		expectedPercentage uint32
 	}{
 		{
-			record:             []byte(`{"dv3_1":0}`),
+			record:             []byte(`{"dv3_2":0}`),
 			expectedPercentage: 0,
 		},
 		{
-			record:             []byte(`{"dv3_1":39}`),
+			record:             []byte(`{"dv3_2":39}`),
 			expectedPercentage: 39,
 		},
 		{
-			record:             []byte(`{"dv3_1":100}`),
+			record:             []byte(`{"dv3_2":100}`),
 			expectedPercentage: 100,
 		},
 		{
@@ -40,7 +40,7 @@ func TestUnmarshalFeaturesRecord(t *testing.T) {
 			record: []byte(`{"kyber":768}`), // Unmarshal to default struct if key is not present
 		},
 		{
-			record: []byte(`{"pq": 101,"dv3":100}`), // Expired keys don't unmarshal to anything
+			record: []byte(`{"pq": 101,"dv3":100,"dv3_1":100}`), // Expired keys don't unmarshal to anything
 		},
 	}
 
@@ -111,10 +111,10 @@ func TestFeaturePrecedenceEvaluationDatagramVersion(t *testing.T) {
 		},
 		{
 			name:             "user_specified_v3",
-			cli:              []string{FeatureDatagramV3_1},
+			cli:              []string{FeatureDatagramV3_2},
 			remote:           featuresRecord{},
-			expectedFeatures: dedupAndRemoveFeatures(append(defaultFeatures, FeatureDatagramV3_1)),
-			expectedVersion:  FeatureDatagramV3_1,
+			expectedFeatures: dedupAndRemoveFeatures(append(defaultFeatures, FeatureDatagramV3_2)),
+			expectedVersion:  FeatureDatagramV3_2,
 		},
 	}
 
@@ -150,6 +150,12 @@ func TestDeprecatedFeaturesRemoved(t *testing.T) {
 			remote:           featuresRecord{},
 			expectedFeatures: defaultFeatures,
 		},
+		{
+			name:             "support_datagram_v3_1",
+			cli:              []string{DeprecatedFeatureDatagramV3_1},
+			remote:           featuresRecord{},
+			expectedFeatures: defaultFeatures,
+		},
 	}
 
 	for _, test := range tests {