define ethereum transaction validation

Author: vedhavyas

frame/ethereum/src/extension.rs

@@ -0,0 +1,124 @@
+//! Extensions for unsigned general extrinsic for ethereum pallet
+
+use crate::pallet::Call as EthereumCall;
+use crate::{Config, Origin, Pallet as Ethereum, RawOrigin};
+use ethereum_types::H160;
+use fp_evm::TransactionValidationError;
+use frame_support::pallet_prelude::{PhantomData, TypeInfo};
+use frame_system::pallet_prelude::{OriginFor, RuntimeCallFor};
+use scale_codec::{Decode, Encode};
+use scale_info::prelude::fmt;
+use sp_runtime::impl_tx_ext_default;
+use sp_runtime::traits::{
+	AsSystemOriginSigner, DispatchInfoOf, DispatchOriginOf, Dispatchable, Implication,
+	TransactionExtension, ValidateResult,
+};
+use sp_runtime::transaction_validity::{
+	InvalidTransaction, TransactionSource, TransactionValidityError, ValidTransaction,
+};
+
+/// Trait to be implemented by the Runtime call for Ethereum call conversion and additional validations.
+pub trait EthereumTransactionHook<Runtime>
+where
+	Runtime: Config,
+	OriginFor<Runtime>: Into<Result<RawOrigin, OriginFor<Runtime>>>,
+{
+	fn maybe_ethereum_call(&self) -> Option<&EthereumCall<Runtime>>;
+
+	fn additional_validation(
+		&self,
+		_signer: H160,
+		_source: TransactionSource,
+	) -> Result<(), TransactionValidityError> {
+		Ok(())
+	}
+}
+
+/// Extensions for pallet-ethereum unsigned extrinsics.
+#[derive(Encode, Decode, Clone, Eq, PartialEq, TypeInfo)]
+pub struct EthereumExtension<Runtime>(PhantomData<Runtime>);
+
+impl<Runtime> EthereumExtension<Runtime> {
+	pub fn new() -> Self {
+		Self(PhantomData)
+	}
+}
+
+impl<Runtime> Default for EthereumExtension<Runtime> {
+	fn default() -> Self {
+		Self::new()
+	}
+}
+
+impl<T: Config> fmt::Debug for EthereumExtension<T> {
+	#[cfg(feature = "std")]
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		write!(f, "EthereumExtension",)
+	}
+
+	#[cfg(not(feature = "std"))]
+	fn fmt(&self, _: &mut fmt::Formatter<'_>) -> fmt::Result {
+		Ok(())
+	}
+}
+
+impl<Runtime> EthereumExtension<Runtime> where
+	Runtime: Config + scale_info::TypeInfo + fmt::Debug + Send + Sync
+{
+}
+
+impl<Runtime> TransactionExtension<RuntimeCallFor<Runtime>> for EthereumExtension<Runtime>
+where
+	Runtime: Config + scale_info::TypeInfo + fmt::Debug + Send + Sync,
+	<RuntimeCallFor<Runtime> as Dispatchable>::RuntimeOrigin:
+		AsSystemOriginSigner<<Runtime as frame_system::Config>::AccountId> + From<Origin> + Clone,
+	OriginFor<Runtime>: Into<Result<RawOrigin, OriginFor<Runtime>>>,
+	RuntimeCallFor<Runtime>: EthereumTransactionHook<Runtime>,
+{
+	const IDENTIFIER: &'static str = "EthereumExtension";
+	type Implicit = ();
+	type Val = ();
+	type Pre = ();
+
+	fn validate(
+		&self,
+		origin: DispatchOriginOf<RuntimeCallFor<Runtime>>,
+		call: &RuntimeCallFor<Runtime>,
+		_info: &DispatchInfoOf<RuntimeCallFor<Runtime>>,
+		_len: usize,
+		_self_implicit: Self::Implicit,
+		_inherited_implication: &impl Implication,
+		source: TransactionSource,
+	) -> ValidateResult<Self::Val, RuntimeCallFor<Runtime>> {
+		// we only care about unsigned calls
+		if origin.as_system_origin_signer().is_some() {
+			return Ok((ValidTransaction::default(), (), origin));
+		};
+
+		let transaction = match call.maybe_ethereum_call() {
+			Some(EthereumCall::transact { transaction }) => transaction,
+			_ => return Ok((ValidTransaction::default(), (), origin)),
+		};
+
+		// check signer
+		let signer = Ethereum::<Runtime>::recover_signer(transaction).ok_or(
+			InvalidTransaction::Custom(TransactionValidationError::InvalidSignature as u8),
+		)?;
+
+		// validation on transactions based on pre_dispatch or mempool validation.
+		let pre_dispatch = source == TransactionSource::InBlock;
+		let validity = if pre_dispatch {
+			Ethereum::<Runtime>::validate_transaction_in_block(signer, transaction)
+				.map(|_| ValidTransaction::default())
+		} else {
+			Ethereum::<Runtime>::validate_transaction_in_pool(signer, transaction)
+		}?;
+
+		// do any additional validations
+		call.additional_validation(signer, source)?;
+
+		Ok((validity, (), Origin::EthereumTransaction(signer).into()))
+	}
+
+	impl_tx_ext_default!(RuntimeCallFor<Runtime>; prepare weight);
+}

frame/ethereum/src/lib.rs

@@ -27,6 +27,7 @@
 
 extern crate alloc;
 
+pub mod extension;
 #[cfg(all(feature = "std", test))]
 mod mock;
 #[cfg(all(feature = "std", test))]