ibft: add round number to timeout event

This prevents unjustified pre-prepare messages from block proposer when
it receives F+1 round-change messages before timeout.

consensus/istanbul/core/core.go

@@ -121,9 +121,6 @@ func (c *core) startNewRound(round *big.Int) {
 	defer c.currentMutex.Unlock()
 	defer c.newRoundChangeTimer()
 
-	// Stop running timers
-	c.stopTimer()
-
 	var logger log.Logger
 	if c.current == nil {
 		logger = c.logger.New("old.round", -1, "old.seq", 0)
@@ -296,7 +293,7 @@ func (c *core) newRoundChangeTimer() {
 	c.currentLogger(true, nil).Trace("IBFT: start new ROUND-CHANGE timer", "timeout", timeout.Seconds())
 	c.cleanLogger.Info("[Consensus]: Start new ROUND-CHANGE timer", "timeout", timeout.Seconds())
 	c.roundChangeTimer = time.AfterFunc(timeout, func() {
-		c.sendEvent(timeoutEvent{})
+		c.sendEvent(timeoutEvent{round: round})
 	})
 }
 

consensus/istanbul/core/events.go

@@ -26,4 +26,6 @@ type backlogEvent struct {
 	msg qbfttypes.QBFTMessage
 }
 
-type timeoutEvent struct{}
+type timeoutEvent struct {
+	round uint64
+}

consensus/istanbul/core/handler.go

@@ -141,12 +141,17 @@ func (c *core) handleEvents() {
 				// if successfully processed, we gossip message to other validators
 				c.backend.Gossip(c.valSet, ev.msg.Code(), data)
 			}
-		case _, ok := <-c.timeoutSub.Chan():
+		case event, ok := <-c.timeoutSub.Chan():
 			// we received a round change timeout
 			if !ok {
 				return
 			}
-			c.handleTimeoutMsg()
+			switch ev := event.Data.(type) {
+			case timeoutEvent:
+				if c.current != nil && c.current.Round().Uint64() == ev.round {
+					c.handleTimeoutMsg()
+				}
+			}
 		case event, ok := <-c.finalCommittedSub.Chan():
 			// our block proposal got committed
 			if !ok {