Avoid to take into account wrong versions of protocols in Vsn.

memberlist.go

@@ -72,6 +72,15 @@ type Memberlist struct {
 	logger *log.Logger
 }
 
+// BuildVsnArray creates the array of Vsn
+func (conf *Config) BuildVsnArray() []uint8 {
+	return []uint8{
+		ProtocolVersionMin, ProtocolVersionMax, conf.ProtocolVersion,
+		conf.DelegateProtocolMin, conf.DelegateProtocolMax,
+		conf.DelegateProtocolVersion,
+	}
+}
+
 // newMemberlist creates the network listeners.
 // Does not schedule execution of background maintenance.
 func newMemberlist(conf *Config) (*Memberlist, error) {
@@ -402,11 +411,7 @@ func (m *Memberlist) setAlive() error {
 		Addr:        addr,
 		Port:        uint16(port),
 		Meta:        meta,
-		Vsn: []uint8{
-			ProtocolVersionMin, ProtocolVersionMax, m.config.ProtocolVersion,
-			m.config.DelegateProtocolMin, m.config.DelegateProtocolMax,
-			m.config.DelegateProtocolVersion,
-		},
+		Vsn:         m.config.BuildVsnArray(),
 	}
 	m.aliveNode(&a, nil, true)
 	return nil
@@ -447,11 +452,7 @@ func (m *Memberlist) UpdateNode(timeout time.Duration) error {
 		Addr:        state.Addr,
 		Port:        state.Port,
 		Meta:        meta,
-		Vsn: []uint8{
-			ProtocolVersionMin, ProtocolVersionMax, m.config.ProtocolVersion,
-			m.config.DelegateProtocolMin, m.config.DelegateProtocolMax,
-			m.config.DelegateProtocolVersion,
-		},
+		Vsn:         m.config.BuildVsnArray(),
 	}
 	notifyCh := make(chan struct{})
 	m.aliveNode(&a, notifyCh, true)

net_test.go

@@ -569,6 +569,10 @@ func TestSendMsg_Piggyback(t *testing.T) {
 		Node:        "rand",
 		Addr:        []byte{127, 0, 0, 255},
 		Meta:        nil,
+		Vsn: []uint8{
+			ProtocolVersionMin, ProtocolVersionMax, ProtocolVersionMin,
+			1, 1, 1,
+		},
 	}
 	m.encodeAndBroadcast("rand", aliveMsg, &a)
 

state.go

@@ -850,11 +850,26 @@ func (m *Memberlist) aliveNode(a *alive, notify chan struct{}, bootstrap bool) {
 		return
 	}
 
+	if len(a.Vsn) >= 3 {
+		pMin := a.Vsn[0]
+		pMax := a.Vsn[1]
+		pCur := a.Vsn[2]
+		if pMin == 0 || pMax == 0 || pMin > pMax {
+			m.logger.Printf("[WARN] memberlist: Ignoring an alive message for '%s' (%v:%d) because protocol version(s) are wrong: %d <= %d <= %d should be >0", a.Node, net.IP(a.Addr), a.Port, pMin, pCur, pMax)
+			return
+		}
+	}
+
 	// Invoke the Alive delegate if any. This can be used to filter out
 	// alive messages based on custom logic. For example, using a cluster name.
 	// Using a merge delegate is not enough, as it is possible for passive
 	// cluster merging to still occur.
 	if m.config.Alive != nil {
+		if len(a.Vsn) < 6 {
+			m.logger.Printf("[WARN] memberlist: ignoring alive message for '%s' (%v:%d) because Vsn is not present",
+				a.Node, net.IP(a.Addr), a.Port)
+			return
+		}
 		node := &Node{
 			Name: a.Node,
 			Addr: a.Addr,
@@ -886,6 +901,14 @@ func (m *Memberlist) aliveNode(a *alive, notify chan struct{}, bootstrap bool) {
 			},
 			State: stateDead,
 		}
+		if len(a.Vsn) > 5 {
+			state.PMin = a.Vsn[0]
+			state.PMax = a.Vsn[1]
+			state.PCur = a.Vsn[2]
+			state.DMin = a.Vsn[3]
+			state.DMax = a.Vsn[4]
+			state.DCur = a.Vsn[5]
+		}
 
 		// Add to map
 		m.nodeMap[a.Node] = state
@@ -965,9 +988,8 @@ func (m *Memberlist) aliveNode(a *alive, notify chan struct{}, bootstrap bool) {
 			bytes.Equal(a.Vsn, versions) {
 			return
 		}
-
 		m.refute(state, a.Incarnation)
-		m.logger.Printf("[WARN] memberlist: Refuting an alive message")
+		m.logger.Printf("[WARN] memberlist: Refuting an alive message for '%s' (%v:%d) meta:(%v VS %v), vsn:(%v VS %v)", a.Node, net.IP(a.Addr), a.Port, a.Meta, state.Meta, a.Vsn, versions)
 	} else {
 		m.encodeBroadcastNotify(a.Node, aliveMsg, a, notify)