Disconnect peers on a fork (#1738)

ethcore/res/ethereum/classic.json

@@ -18,7 +18,9 @@
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",
 		"minGasLimit": "0x1388",
-		"networkID" : "0x1"
+		"networkID" : "0x1",
+		"forkBlock": "0x1d4c00",
+		"forkCanonHash": "0x94365e3a8c0b35089c1d1195081fe7489b528a84b22199c916180db8b28ade7f"
 	},
 	"genesis": {
 		"seal": {

ethcore/res/ethereum/frontier.json

@@ -137,7 +137,9 @@
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",
 		"minGasLimit": "0x1388",
-		"networkID" : "0x1"
+		"networkID" : "0x1",
+		"forkBlock": "0x1d4c00",
+		"forkCanonHash": "0x4985f5ca3d2afbec36529aa96f74de3cc10a2a4a6c44f2157a57d2c6059a11bb"
 	},
 	"genesis": {
 		"seal": {

ethcore/src/spec/spec.rs

@@ -38,6 +38,8 @@ pub struct CommonParams {
 	pub network_id: U256,
 	/// Minimum gas limit.
 	pub min_gas_limit: U256,
+	/// Fork block to check.
+	pub fork_block: Option<(BlockNumber, H256)>,
 }
 
 impl From<ethjson::spec::Params> for CommonParams {
@@ -47,6 +49,7 @@ impl From<ethjson::spec::Params> for CommonParams {
 			maximum_extra_data_size: p.maximum_extra_data_size.into(),
 			network_id: p.network_id.into(),
 			min_gas_limit: p.min_gas_limit.into(),
+			fork_block: if let (Some(n), Some(h)) = (p.fork_block, p.fork_hash) { Some((n.into(), h.into())) } else { None },
 		}
 	}
 }
@@ -151,6 +154,9 @@ impl Spec {
 	/// Get the configured Network ID.
 	pub fn network_id(&self) -> U256 { self.params.network_id }
 
+	/// Get the configured network fork block.
+	pub fn fork_block(&self) -> Option<(BlockNumber, H256)> { self.params.fork_block }
+
 	/// Get the header of the genesis block.
 	pub fn genesis_header(&self) -> Header {
 		Header {