Max gas limit and min gas price (#4661)

* Max gas limit and min gas price

* Tests

* Limit gas limit ceiling

ethcore/src/ethereum/ethash.rs

@@ -79,6 +79,14 @@ pub struct EthashParams {
 	pub ecip1010_continue_transition: u64,
 	/// Maximum amount of code that can be deploying into a contract.
 	pub max_code_size: u64,
+	/// Number of first block where the max gas limit becomes effective.
+	pub max_gas_limit_transition: u64,
+	/// Maximum valid block gas limit,
+	pub max_gas_limit: U256,
+	/// Number of first block where the minimum gas price becomes effective.
+	pub min_gas_price_transition: u64,
+	/// Do not alow transactions with lower gas price.
+	pub min_gas_price: U256,
 }
 
 impl From<ethjson::spec::EthashParams> for EthashParams {
@@ -106,6 +114,10 @@ impl From<ethjson::spec::EthashParams> for EthashParams {
 			ecip1010_pause_transition: p.ecip1010_pause_transition.map_or(u64::max_value(), Into::into),
 			ecip1010_continue_transition: p.ecip1010_continue_transition.map_or(u64::max_value(), Into::into),
 			max_code_size: p.max_code_size.map_or(u64::max_value(), Into::into),
+			max_gas_limit_transition: p.max_gas_limit_transition.map_or(u64::max_value(), Into::into),
+			max_gas_limit: p.max_gas_limit.map_or(U256::max_value(), Into::into),
+			min_gas_price_transition: p.min_gas_price_transition.map_or(u64::max_value(), Into::into),
+			min_gas_price: p.min_gas_price.map_or(U256::zero(), Into::into),
 		}
 	}
 }
@@ -174,8 +186,12 @@ impl Engine for Ethash {
 		}
 	}
 
-	fn populate_from_parent(&self, header: &mut Header, parent: &Header, gas_floor_target: U256, gas_ceil_target: U256) {
+	fn populate_from_parent(&self, header: &mut Header, parent: &Header, gas_floor_target: U256, mut gas_ceil_target: U256) {
 		let difficulty = self.calculate_difficulty(header, parent);
+		if header.number() >= self.ethash_params.max_gas_limit_transition && gas_ceil_target > self.ethash_params.max_gas_limit {
+			warn!("Gas limit target is limited to {}", self.ethash_params.max_gas_limit);
+			gas_ceil_target = self.ethash_params.max_gas_limit;
+		}
 		let gas_limit = {
 			let gas_limit = parent.gas_limit().clone();
 			let bound_divisor = self.ethash_params.gas_limit_bound_divisor;
@@ -312,11 +328,15 @@ impl Engine for Ethash {
 			return Err(From::from(BlockError::InvalidDifficulty(Mismatch { expected: expected_difficulty, found: header.difficulty().clone() })))
 		}
 		let gas_limit_divisor = self.ethash_params.gas_limit_bound_divisor;
-		let min_gas = parent.gas_limit().clone() - parent.gas_limit().clone() / gas_limit_divisor;
+		let parent_gas_limit = *parent.gas_limit();
-		let max_gas = parent.gas_limit().clone() + parent.gas_limit().clone() / gas_limit_divisor;
+		let min_gas = parent_gas_limit - parent_gas_limit / gas_limit_divisor;
+		let max_gas = parent_gas_limit + parent_gas_limit / gas_limit_divisor;
 		if header.gas_limit() <= &min_gas || header.gas_limit() >= &max_gas {
 			return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit().clone() })));
 		}
+		if header.number() >= self.ethash_params.max_gas_limit_transition && header.gas_limit() > &self.ethash_params.max_gas_limit && header.gas_limit() > &parent_gas_limit {
+			return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(self.ethash_params.max_gas_limit), found: header.gas_limit().clone() })));
+		}
 		Ok(())
 	}
 
@@ -331,6 +351,10 @@ impl Engine for Ethash {
 			}
 		}
 
+		if header.number() >= self.ethash_params.min_gas_price_transition && t.gas_price < self.ethash_params.min_gas_price {
+			return Err(TransactionError::InsufficientGasPrice { minimal: self.ethash_params.min_gas_price, got: t.gas_price }.into());
+		}
+
 		Ok(())
 	}
 }
@@ -853,4 +877,82 @@ mod tests {
 		let difficulty = ethash.calculate_difficulty(&header, &parent_header);
 		assert_eq!(U256::from(12543204905719u64), difficulty);
 	}
+
+	#[test]
+	fn rejects_blocks_over_max_gas_limit() {
+		let spec = new_homestead_test();
+		let mut ethparams = get_default_ethash_params();
+		ethparams.max_gas_limit_transition = 10;
+		ethparams.max_gas_limit = 100_000.into();
+
+		let mut parent_header = Header::default();
+		parent_header.set_number(1);
+		parent_header.set_gas_limit(100_000.into());
+		let mut header = Header::default();
+		header.set_number(parent_header.number() + 1);
+		header.set_gas_limit(100_001.into());
+		header.set_difficulty(ethparams.minimum_difficulty);
+		let ethash = Ethash::new(spec.params, ethparams, BTreeMap::new());
+		assert!(ethash.verify_block_family(&header, &parent_header, None).is_ok());
+
+		parent_header.set_number(9);
+		header.set_number(parent_header.number() + 1);
+
+		parent_header.set_gas_limit(99_999.into());
+		header.set_gas_limit(100_000.into());
+		assert!(ethash.verify_block_family(&header, &parent_header, None).is_ok());
+
+		parent_header.set_gas_limit(200_000.into());
+		header.set_gas_limit(200_000.into());
+		assert!(ethash.verify_block_family(&header, &parent_header, None).is_ok());
+
+		parent_header.set_gas_limit(100_000.into());
+		header.set_gas_limit(100_001.into());
+		assert!(ethash.verify_block_family(&header, &parent_header, None).is_err());
+
+		parent_header.set_gas_limit(200_000.into());
+		header.set_gas_limit(200_001.into());
+		assert!(ethash.verify_block_family(&header, &parent_header, None).is_err());
+	}
+
+	#[test]
+	fn rejects_transactions_below_min_gas_price() {
+		use ethkey::{Generator, Random};
+		use types::transaction::{Transaction, Action};
+
+		let spec = new_homestead_test();
+		let mut ethparams = get_default_ethash_params();
+		ethparams.min_gas_price_transition = 10;
+		ethparams.min_gas_price = 100000.into();
+
+		let mut header = Header::default();
+		header.set_number(1);
+
+		let keypair = Random.generate().unwrap();
+		let tx1 = Transaction {
+			action: Action::Create,
+			value: U256::zero(),
+			data: Vec::new(),
+			gas: 100_000.into(),
+			gas_price: 100_000.into(),
+			nonce: U256::zero(),
+		}.sign(keypair.secret(), None).into();
+
+		let tx2 = Transaction {
+			action: Action::Create,
+			value: U256::zero(),
+			data: Vec::new(),
+			gas: 100_000.into(),
+			gas_price: 99_999.into(),
+			nonce: U256::zero(),
+		}.sign(keypair.secret(), None).into();
+
+		let ethash = Ethash::new(spec.params, ethparams, BTreeMap::new());
+		assert!(ethash.verify_transaction_basic(&tx1, &header).is_ok());
+		assert!(ethash.verify_transaction_basic(&tx2, &header).is_ok());
+
+		header.set_number(10);
+		assert!(ethash.verify_transaction_basic(&tx1, &header).is_ok());
+		assert!(ethash.verify_transaction_basic(&tx2, &header).is_err());
+	}
 }

ethcore/src/tests/helpers.rs

@@ -456,5 +456,9 @@ pub fn get_default_ethash_params() -> EthashParams{
 		ecip1010_pause_transition: u64::max_value(),
 		ecip1010_continue_transition: u64::max_value(),
 		max_code_size: u64::max_value(),
+		max_gas_limit_transition: u64::max_value(),
+		max_gas_limit: U256::max_value(),
+		min_gas_price_transition: u64::max_value(),
+		min_gas_price: U256::zero(),
 	}
 }

json/src/spec/ethash.rs

@@ -97,6 +97,21 @@ pub struct EthashParams {
 	#[serde(rename="maxCodeSize")]
 	pub max_code_size: Option<Uint>,
 
+	/// See main EthashParams docs.
+	#[serde(rename="maxGasLimitTransition")]
+	pub max_gas_limit_transition: Option<Uint>,
+
+	/// See main EthashParams docs.
+	#[serde(rename="maxGasLimit")]
+	pub max_gas_limit: Option<Uint>,
+
+	/// See main EthashParams docs.
+	#[serde(rename="minGasPriceTransition")]
+	pub min_gas_price_transition: Option<Uint>,
+
+	/// See main EthashParams docs.
+	#[serde(rename="minGasPrice")]
+	pub min_gas_price: Option<Uint>,
 }
 
 /// Ethash engine deserialization.