Merge pull request ethereum#170 from etclabscore/feat/immutability-th…

…reshold-flag

install immutability threshold flags

cmd/geth/main.go

@@ -108,6 +108,8 @@ var (
 		utils.UltraLightFractionFlag,
 		utils.UltraLightOnlyAnnounceFlag,
 		utils.WhitelistFlag,
+		utils.ImmutabilityThresholdFullFlag,
+		utils.ImmutabilityThresholdLightFlag,
 		utils.CacheFlag,
 		utils.CacheDatabaseFlag,
 		utils.CacheTrieFlag,

cmd/geth/usage.go

@@ -59,6 +59,8 @@ var AppHelpFlagGroups = []flags.FlagGroup{
 			utils.IdentityFlag,
 			utils.LightKDFFlag,
 			utils.WhitelistFlag,
+			utils.ImmutabilityThresholdFullFlag,
+			utils.ImmutabilityThresholdLightFlag,
 		},
 	},
 	{

cmd/utils/flags.go

@@ -65,6 +65,7 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/params/types/ctypes"
 	"github.com/ethereum/go-ethereum/params/types/genesisT"
+	"github.com/ethereum/go-ethereum/params/vars"
 	"github.com/ethereum/go-ethereum/rpc"
 	whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
 	pcsclite "github.com/gballet/go-libpcsclite"
@@ -240,6 +241,16 @@ var (
 		Name:  "whitelist",
 		Usage: "Comma separated block number-to-hash mappings to enforce (<number>=<hash>)",
 	}
+	ImmutabilityThresholdFullFlag = cli.Int64Flag{
+		Name:  "immutabilitythreshold.full",
+		Usage: "Full Immutability Threshold is the number of blocks after which a chain segment is considered immutable (i.e. soft finality).",
+		Value: int64(vars.FullImmutabilityThreshold),
+	}
+	ImmutabilityThresholdLightFlag = cli.Int64Flag{
+		Name:  "immutabilitythreshold.light",
+		Usage: "Light Immutability Threshold is the number of blocks after which a header chain segment is considered immutable for light client (i.e. soft finality)",
+		Value: int64(vars.LightImmutabilityThreshold),
+	}
 	// Light server and client settings
 	LightServeFlag = cli.IntFlag{
 		Name:  "light.serve",
@@ -1499,6 +1510,26 @@ func setWhitelist(ctx *cli.Context, cfg *eth.Config) {
 	}
 }
 
+func setImmutabilityThresholds(ctx *cli.Context) {
+	if ctx.GlobalIsSet(ImmutabilityThresholdFullFlag.Name) {
+		v := ctx.GlobalInt64(ImmutabilityThresholdFullFlag.Name)
+		if v < 0 {
+			Fatalf("immutability threshold must be greater than or equal to 0")
+		}
+		// Type conversion will fail if type max exceeded. That's a far-edge case and not worth handling.
+		vars.FullImmutabilityThreshold = uint64(v)
+		log.Info("Using configured full immutability threshold", "threshold", vars.FullImmutabilityThreshold)
+	}
+	if ctx.GlobalIsSet(ImmutabilityThresholdLightFlag.Name) {
+		v := ctx.GlobalInt64(ImmutabilityThresholdLightFlag.Name)
+		if v < 0 {
+			Fatalf("immutability threshold must be greater than or equal to 0")
+		}
+		vars.LightImmutabilityThreshold = uint64(v)
+		log.Info("Using configured light immutability threshold", "threshold", vars.LightImmutabilityThreshold)
+	}
+}
+
 // CheckExclusive verifies that only a single instance of the provided flags was
 // set by the user. Each flag might optionally be followed by a string type to
 // specialize it further.
@@ -1574,6 +1605,7 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *eth.Config) {
 	setEthash(ctx, cfg)
 	setMiner(ctx, &cfg.Miner)
 	setWhitelist(ctx, cfg)
+	setImmutabilityThresholds(ctx)
 	setLes(ctx, cfg)
 
 	if ctx.GlobalIsSet(SyncModeFlag.Name) {

consensus/clique/clique.go

@@ -370,7 +370,7 @@ func (c *Clique) snapshot(chain consensus.ChainReader, number uint64, hash commo
 		// at a checkpoint block without a parent (light client CHT), or we have piled
 		// up more headers than allowed to be reorged (chain reinit from a freezer),
 		// consider the checkpoint trusted and snapshot it.
-		if number == 0 || (number%c.config.Epoch == 0 && (len(headers) > vars.FullImmutabilityThreshold || chain.GetHeaderByNumber(number-1) == nil)) {
+		if number == 0 || (number%c.config.Epoch == 0 && (uint64(len(headers)) > vars.FullImmutabilityThreshold || chain.GetHeaderByNumber(number-1) == nil)) {
 			checkpoint := chain.GetHeaderByNumber(number)
 			if checkpoint != nil {
 				hash := checkpoint.Hash()

params/vars/network_params.go

@@ -56,16 +56,18 @@ const (
 
 	// CheckpointProcessConfirmations is the number before a checkpoint is generated
 	CheckpointProcessConfirmations = 256
+)
 
+var (
 	// FullImmutabilityThreshold is the number of blocks after which a chain segment is
 	// considered immutable (i.e. soft finality). It is used by the downloader as a
 	// hard limit against deep ancestors, by the blockchain against deep reorgs, by
 	// the freezer as the cutoff threshold and by clique as the snapshot trust limit.
-	FullImmutabilityThreshold = 90000
+	FullImmutabilityThreshold uint64 = 90000
 
 	// LightImmutabilityThreshold is the number of blocks after which a header chain
 	// segment is considered immutable for light client(i.e. soft finality). It is used by
 	// the downloader as a hard limit against deep ancestors, by the blockchain against deep
 	// reorgs, by the light pruner as the pruning validity guarantee.
-	LightImmutabilityThreshold = 30000
+	LightImmutabilityThreshold uint64 = 30000
 )