masternode takes turn (circle) to propose block

consensus/clique/clique.go

@@ -374,6 +374,19 @@ func (c *Clique) GetSnapshot(chain consensus.ChainReader, header *types.Header)
 	return snap, nil
 }
 
+func position(list []common.Address, x common.Address) int {
+	for i, item := range list {
+		if item == x {
+			return i
+		}
+	}
+	return -1
+}
+
+func YourTurn(snap *Snapshot, pre, cur common.Address) bool {
+	return (position(snap.signers(), pre)+1) % len(snap.signers()) == position(snap.signers(), cur)
+}
+
 // snapshot retrieves the authorization snapshot at a given point in time.
 func (c *Clique) snapshot(chain consensus.ChainReader, number uint64, hash common.Hash, parents []*types.Header) (*Snapshot, error) {
 	// Search for a snapshot in memory or on disk for checkpoints

miner/worker.go

@@ -397,6 +397,24 @@ func (self *worker) commitNewWork() {
 	tstart := time.Now()
 	parent := self.chain.CurrentBlock()
 
+	// Only try to commit new work if we are mining
+	if atomic.LoadInt32(&self.mining) == 1 {
+		// check if we are right after parent's coinbase in the list
+		// only go with Clique
+		if self.config.Clique != nil {
+			c := self.engine.(*clique.Clique)
+			snap, err := c.GetSnapshot(self.chain, parent.Header())
+			if err != nil {
+				log.Error("Failed when trying to commit new work", "err", err)
+				return
+			}
+			if !clique.YourTurn(snap, parent.Coinbase(), self.coinbase) {
+				log.Info("Not our turn to commit block", "wait")
+				return
+			}
+		}
+	}
+
 	tstamp := tstart.Unix()
 	if parent.Time().Cmp(new(big.Int).SetInt64(tstamp)) >= 0 {
 		tstamp = parent.Time().Int64() + 1