be explicit about protocol in state errors: TCP or UDP (#258)

state.go

@@ -329,7 +329,7 @@ func (m *Memberlist) probeNode(node *nodeState) {
 	}()
 	if node.State == StateAlive {
 		if err := m.encodeAndSendMsg(node.FullAddress(), pingMsg, &ping); err != nil {
-			m.logger.Printf("[ERR] memberlist: Failed to send ping: %s", err)
+			m.logger.Printf("[ERR] memberlist: Failed to send UDP ping: %s", err)
 			if failedRemote(err) {
 				goto HANDLE_REMOTE_FAILURE
 			} else {
@@ -339,7 +339,7 @@ func (m *Memberlist) probeNode(node *nodeState) {
 	} else {
 		var msgs [][]byte
 		if buf, err := encode(pingMsg, &ping); err != nil {
-			m.logger.Printf("[ERR] memberlist: Failed to encode ping message: %s", err)
+			m.logger.Printf("[ERR] memberlist: Failed to encode UDP ping message: %s", err)
 			return
 		} else {
 			msgs = append(msgs, buf.Bytes())
@@ -354,7 +354,7 @@ func (m *Memberlist) probeNode(node *nodeState) {
 
 		compound := makeCompoundMessage(msgs)
 		if err := m.rawSendMsgPacket(node.FullAddress(), &node.Node, compound.Bytes()); err != nil {
-			m.logger.Printf("[ERR] memberlist: Failed to send compound ping and suspect message to %s: %s", addr, err)
+			m.logger.Printf("[ERR] memberlist: Failed to send UDP compound ping and suspect message to %s: %s", addr, err)
 			if failedRemote(err) {
 				goto HANDLE_REMOTE_FAILURE
 			} else {
@@ -393,7 +393,7 @@ func (m *Memberlist) probeNode(node *nodeState) {
 		// probe interval it will give the TCP fallback more time, which
 		// is more active in dealing with lost packets, and it gives more
 		// time to wait for indirect acks/nacks.
-		m.logger.Printf("[DEBUG] memberlist: Failed ping: %s (timeout reached)", node.Name)
+		m.logger.Printf("[DEBUG] memberlist: Failed UDP ping: %s (timeout reached)", node.Name)
 	}
 
 HANDLE_REMOTE_FAILURE:
@@ -426,7 +426,7 @@ HANDLE_REMOTE_FAILURE:
 		}
 
 		if err := m.encodeAndSendMsg(peer.FullAddress(), indirectPingMsg, &ind); err != nil {
-			m.logger.Printf("[ERR] memberlist: Failed to send indirect ping: %s", err)
+			m.logger.Printf("[ERR] memberlist: Failed to send indirect UDP ping: %s", err)
 		}
 	}
 
@@ -453,7 +453,7 @@ HANDLE_REMOTE_FAILURE:
 				if ne, ok := err.(net.Error); ok && ne.Timeout() {
 					to = fmt.Sprintf("timeout %s: ", probeInterval)
 				}
-				m.logger.Printf("[ERR] memberlist: Failed fallback ping: %s%s", to, err)
+				m.logger.Printf("[ERR] memberlist: Failed fallback TCP ping: %s%s", to, err)
 			} else {
 				fallbackCh <- didContact
 			}
@@ -478,7 +478,7 @@ HANDLE_REMOTE_FAILURE:
 	// any additional time here.
 	for didContact := range fallbackCh {
 		if didContact {
-			m.logger.Printf("[WARN] memberlist: Was able to connect to %s but other probes failed, network may be misconfigured", node.Name)
+			m.logger.Printf("[WARN] memberlist: Was able to connect to %s over TCP but UDP probes failed, network may be misconfigured", node.Name)
 			return
 		}
 	}