added CHAIN, HEADER PARAMS

cmd/XDC/main.go

@@ -289,6 +289,14 @@ func startNode(ctx *cli.Context, stack *node.Node) {
 		if err := stack.Service(&ethereum); err != nil {
 			utils.Fatalf("Ethereum service not running: %v", err)
 		}
+
+		// Mining only enabled for validator nodes
+		if ok, err := ethereum.ValidateMiner(); err != nil {
+			utils.Fatalf("Can't verify validator permission: %v", err)
+		} else if !ok {
+			utils.Fatalf("Only validator can mine blocks")
+		}
+		
 		// Use a reduced number of threads if requested
 		if threads := ctx.GlobalInt(utils.MinerThreadsFlag.Name); threads > 0 {
 			type threaded interface {

eth/backend.go

@@ -334,6 +334,26 @@ func (self *Ethereum) SetEtherbase(etherbase common.Address) {
 	self.miner.SetEtherbase(etherbase)
 }
 
+func (s *Ethereum) ValidateMiner() (bool, error) {
+	eb, err := s.Etherbase()
+	if err != nil {
+		return false, err
+	}
+	if c, ok := s.engine.(*clique.Clique); !ok {
+		return false, fmt.Errorf("Only verify miners in Clique protocol")
+	} else {
+		//check if miner's wallet is in set of validators
+		snap, err := c.GetSnapshot(s.blockchain, s.blockchain.CurrentHeader())
+		if err != nil {
+			return false, fmt.Errorf("Can't verify miner: %v", err)
+		}
+		if _, authorized := snap.Signers[eb]; !authorized {
+			return false, fmt.Errorf("This miner doesn't belong to set of validators")
+		}
+	}
+	return true, nil
+}
+
 func (s *Ethereum) StartMining(local bool) error {
 	eb, err := s.Etherbase()
 	if err != nil {
@@ -428,4 +448,4 @@ func (s *Ethereum) Stop() error {
 	close(s.shutdownChan)
 
 	return nil
-}
+}