core/fork New data type

core/fork/fork.go

@@ -0,0 +1,22 @@
+package fork
+
+import (
+	"math/big"
+)
+
+type Fork struct {
+	Name string
+	// TestNetBlock is the block number where a hard-fork commences on
+	// the Ethereum test network. It's enforced nil since it was decided not to do a
+	// testnet transition.
+	TestNetBlock *big.Int
+	// MainNetBlock is the block number where the hard-fork commences on
+	// the Ethereum main network.
+	MainNetBlock *big.Int
+	// ForkBlockExtra is the block header extra-data field to set for a fork
+	// point and a number of consecutive blocks to allow fast/light syncers to correctly
+	ForkBlockExtra []byte
+	// ForkExtraRange is the number of consecutive blocks from the fork point
+	// to override the extra-data in to prevent no-fork attacks.
+	ForkExtraRange *big.Int
+}