Enable STOP message only with -enable_stop

The STOP message has always been only for testing, and should never be
honored on any network except in controlled, short-lived test networks.

cmd/harmony/main.go

@@ -94,6 +94,10 @@ var (
 	shardID      = flag.Int("shard_id", -1, "the shard ID of this node")
 	// logConn logs incoming/outgoing connections
 	logConn = flag.Bool("log_conn", false, "log incoming/outgoing connections")
+	// Enable processing of kill (STOP) message.  Only for automated testing.
+	enableStopMessage = flag.Bool("enable_stop", false,
+		"enable processing of STOP message, e.g. from txgen "+
+			"(USE ONLY IN SHORT-LIVED, PRIVATE TEST NETWORKS)")
 )
 
 func initSetup() {
@@ -227,6 +231,10 @@ func setUpConsensusAndNode(nodeConfig *nodeconfig.ConfigType) (*consensus.Consen
 	currentNode := node.New(nodeConfig.Host, currentConsensus, nodeConfig.MainDB, *isArchival)
 	currentNode.NodeConfig.SetRole(nodeconfig.NewNode)
 	currentNode.AccountKey = nodeConfig.StakingPriKey
+	if *enableStopMessage {
+		utils.GetLogInstance().Warn("enabling STOP message processing for this node")
+		currentNode.ProcessStopMessage = true
+	}
 	utils.GetLogInstance().Info("node account set",
 		"address", crypto.PubkeyToAddress(currentNode.AccountKey.PublicKey))
 

node/node.go

@@ -179,6 +179,11 @@ type Node struct {
 
 	// Used to call smart contract locally
 	ContractCaller *contracts.ContractCaller
+
+	// Enable processing of STOP message.
+	// When enabled ANYONE can bring down this node.
+	// Use only for private testing, and definitely never on prod network.
+	ProcessStopMessage bool
 }
 
 // Blockchain returns the blockchain from node

node/node_handler.go

@@ -175,7 +175,7 @@ func (node *Node) messageHandler(content []byte, sender string) {
 		case proto_node.Control:
 			utils.GetLogInstance().Info("NET: received message: Node/Control")
 			controlType := msgPayload[0]
-			if proto_node.ControlMessageType(controlType) == proto_node.STOP {
+			if proto_node.ControlMessageType(controlType) == proto_node.STOP && node.ProcessStopMessage {
 				utils.GetLogInstance().Debug("Stopping Node", "numBlocks", node.blockchain.CurrentBlock().NumberU64(), "numTxsProcessed", node.countNumTransactionsInBlockchain())
 
 				var avgBlockSizeInBytes common.StorageSize