check for minGasLimit and minDifficulty when constructing block

libethcore/BlockInfo.cpp

@@ -127,8 +127,14 @@ void BlockInfo::populateFromHeader(RLP const& _header, bool _checkNonce)
 	if (gasUsed > gasLimit)
 		BOOST_THROW_EXCEPTION(TooMuchGasUsed() << RequirementError(bigint(gasLimit), bigint(gasUsed)) );
 
+	if (difficulty < c_minimumDifficulty)
+		BOOST_THROW_EXCEPTION(InvalidDifficulty() << RequirementError(bigint(c_minimumDifficulty), bigint(difficulty)) );
+
+	if (gasLimit < c_minGasLimit)
+		BOOST_THROW_EXCEPTION(InvalidGasLimit() << RequirementError(bigint(c_minGasLimit), bigint(gasLimit)) );
+
 	if (number && extraData.size() > c_maximumExtraDataSize)
-		BOOST_THROW_EXCEPTION(ExtraDataTooBig());
+		BOOST_THROW_EXCEPTION(ExtraDataTooBig() << RequirementError(bigint(c_maximumExtraDataSize), bigint(extraData.size())));
 }
 
 void BlockInfo::populate(bytesConstRef _block, bool _checkNonce)
@@ -213,10 +219,6 @@ void BlockInfo::verifyParent(BlockInfo const& _parent) const
 		gasLimit > _parent.gasLimit * (c_gasLimitBoundDivisor + 1) / c_gasLimitBoundDivisor)
 		BOOST_THROW_EXCEPTION(InvalidGasLimit(gasLimit, _parent.gasLimit * (c_gasLimitBoundDivisor - 1) / c_gasLimitBoundDivisor, _parent.gasLimit * (c_gasLimitBoundDivisor + 1) / c_gasLimitBoundDivisor));
 
-	if (gasLimit < _parent.gasLimit * (c_gasLimitBoundDivisor - 1) / c_gasLimitBoundDivisor ||
-		gasLimit > _parent.gasLimit * (c_gasLimitBoundDivisor + 1) / c_gasLimitBoundDivisor)
-		BOOST_THROW_EXCEPTION(InvalidGasLimit(gasLimit, _parent.gasLimit * (c_gasLimitBoundDivisor - 1) / c_gasLimitBoundDivisor, _parent.gasLimit * (c_gasLimitBoundDivisor + 1) / c_gasLimitBoundDivisor));
-
 	if (seedHash != calculateSeedHash(_parent))
 		BOOST_THROW_EXCEPTION(InvalidSeedHash());