Stop at configured block (#2330)

Adds a flag that fails validation for all blocks later than a specific block.
This prevents nodes from accepting and producing blocks after that point.

Also adds an e2e test that verifies the effectiveness of the stopping.

Co-authored-by: alecps <[email protected]>
Co-authored-by: Piers Powlesland <[email protected]>

cmd/geth/main.go

@@ -74,6 +74,7 @@ var (
 		utils.USBFlag,
 		// utils.SmartCardDaemonPathFlag,
 		utils.OverrideHForkFlag,
+		utils.L2MigrationBlockFlag,
 		utils.TxPoolLocalsFlag,
 		utils.TxPoolNoLocalsFlag,
 		utils.TxPoolJournalFlag,

cmd/utils/flags.go

@@ -243,6 +243,11 @@ var (
 		Usage: "Manually specify the hfork block, overriding the bundled setting",
 	}
 
+	L2MigrationBlockFlag = cli.Uint64Flag{
+		Name:  "l2migrationblock",
+		Usage: "Block number at which to halt the network for Celo L2 migration. This is the first block of Celo as an L2, and one after the last block of Celo as an L1. If unset or set to 0, no halt will occur.",
+	}
+
 	BloomFilterSizeFlag = cli.Uint64Flag{
 		Name:  "bloomfilter.size",
 		Usage: "Megabytes of memory allocated to bloom-filter for pruning",
@@ -1723,6 +1728,9 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 	log.Debug("Sanitizing Go's GC trigger", "percent", int(gogc))
 	godebug.SetGCPercent(int(gogc))
 
+	if ctx.GlobalIsSet(L2MigrationBlockFlag.Name) {
+		cfg.L2MigrationBlock = new(big.Int).SetUint64(ctx.GlobalUint64(L2MigrationBlockFlag.Name))
+	}
 	if ctx.GlobalIsSet(SyncModeFlag.Name) {
 		cfg.SyncMode = *GlobalTextMarshaler(ctx, SyncModeFlag.Name).(*downloader.SyncMode)
 	}

consensus/istanbul/backend/engine.go

@@ -125,6 +125,10 @@ func (sb *Backend) verifyHeader(chain consensus.ChainHeaderReader, header *types
 	if header.Number == nil {
 		return errUnknownBlock
 	}
+	if chain.Config().IsL2Migration(header.Number) {
+		sb.logger.Trace("Reject block after L2 migration", "num", header.Number)
+		return fmt.Errorf("Block number %d is after the L2 migration.", header.Number)
+	}
 
 	// If the full chain isn't available (as on mobile devices), don't reject future blocks
 	// This is due to potential clock skew

core/forkid/forkid.go

@@ -224,6 +224,10 @@ func gatherForks(config *params.ChainConfig) []uint64 {
 		if !strings.HasSuffix(field.Name, "Block") {
 			continue
 		}
+		// Do not include L2MigrationBlock in forkid as doing so will prevent syncing with nodes that have not set the L2MigrationBlock flag
+		if field.Name == "L2MigrationBlock" {
+			continue
+		}
 		if field.Type != reflect.TypeOf(new(big.Int)) {
 			continue
 		}

e2e_test/e2e_bench_test.go

@@ -19,7 +19,7 @@ func BenchmarkNet100EmptyBlocks(b *testing.B) {
 			for i := 0; i < b.N; i++ {
 				ac := test.AccountConfig(n, 0)
 				gingerbreadBlock := common.Big0
-				gc, ec, err := test.BuildConfig(ac, gingerbreadBlock)
+				gc, ec, err := test.BuildConfig(ac, gingerbreadBlock, nil)
 				require.NoError(b, err)
 				network, shutdown, err := test.NewNetwork(ac, gc, ec)
 				require.NoError(b, err)
@@ -45,7 +45,7 @@ func BenchmarkNet1000Txs(b *testing.B) {
 
 				ac := test.AccountConfig(n, n)
 				gingerbreadBlock := common.Big0
-				gc, ec, err := test.BuildConfig(ac, gingerbreadBlock)
+				gc, ec, err := test.BuildConfig(ac, gingerbreadBlock, nil)
 				require.NoError(b, err)
 				accounts := test.Accounts(ac.DeveloperAccounts(), gc.ChainConfig())
 				network, shutdown, err := test.NewNetwork(ac, gc, ec)