Merge pull request #1362 from opentensor/chore/refactor-precompiles

Refactor precompiles

Author: sam0x17

precompiles/src/balance_transfer.rs

@@ -1,17 +1,17 @@
 use core::marker::PhantomData;
 
 use frame_support::dispatch::{GetDispatchInfo, PostDispatchInfo};
+use frame_system::RawOrigin;
 use pallet_evm::PrecompileHandle;
 use precompile_utils::EvmResult;
 use sp_core::{H256, U256};
 use sp_runtime::traits::{Dispatchable, StaticLookup, UniqueSaturatedInto};
 
-use crate::parser::{contract_to_origin, parse_pubkey};
 use crate::{PrecompileExt, PrecompileHandleExt};
 
 pub(crate) struct BalanceTransferPrecompile<R>(PhantomData<R>);
 
-impl<R> PrecompileExt for BalanceTransferPrecompile<R>
+impl<R> PrecompileExt<R::AccountId> for BalanceTransferPrecompile<R>
 where
     R: frame_system::Config + pallet_balances::Config + pallet_evm::Config,
     R::AccountId: From<[u8; 32]>,
@@ -24,11 +24,6 @@ where
     <R as pallet_balances::Config>::Balance: TryFrom<U256>,
 {
     const INDEX: u64 = 2048;
-    const ADDRESS_SS58: Option<[u8; 32]> = Some([
-        0x07, 0xec, 0x71, 0x2a, 0x5d, 0x38, 0x43, 0x4d, 0xdd, 0x03, 0x3f, 0x8f, 0x02, 0x4e, 0xcd,
-        0xfc, 0x4b, 0xb5, 0x95, 0x1c, 0x13, 0xc3, 0x08, 0x5c, 0x39, 0x9c, 0x8a, 0x5f, 0x62, 0x93,
-        0x70, 0x5d,
-    ]);
 }
 
 #[precompile_utils::precompile]
@@ -53,18 +48,13 @@ where
             return Ok(());
         }
 
-        let dest = parse_pubkey::<R::AccountId>(address.as_bytes())?.0.into();
+        let dest = R::AccountId::from(address.0).into();
 
         let call = pallet_balances::Call::<R>::transfer_allow_death {
             dest,
             value: amount_sub.unique_saturated_into(),
         };
 
-        handle.try_dispatch_runtime_call::<R, _>(
-            call,
-            contract_to_origin(
-                &Self::ADDRESS_SS58.expect("ADDRESS_SS58 is defined for BalanceTransferPrecompile"),
-            )?,
-        )
+        handle.try_dispatch_runtime_call::<R, _>(call, RawOrigin::Signed(Self::account_id()))
     }
 }

precompiles/src/ed25519.rs

@@ -1,21 +1,26 @@
 extern crate alloc;
 
 use alloc::vec::Vec;
+use core::marker::PhantomData;
 
 use ed25519_dalek::{Signature, Verifier, VerifyingKey};
 use fp_evm::{ExitError, ExitSucceed, LinearCostPrecompile, PrecompileFailure};
 
 use crate::PrecompileExt;
-use crate::parser::parse_slice;
 
-pub(crate) struct Ed25519Verify;
+pub(crate) struct Ed25519Verify<A>(PhantomData<A>);
 
-impl PrecompileExt for Ed25519Verify {
+impl<A> PrecompileExt<A> for Ed25519Verify<A>
+where
+    A: From<[u8; 32]>,
+{
     const INDEX: u64 = 1026;
-    const ADDRESS_SS58: Option<[u8; 32]> = None;
 }
 
-impl LinearCostPrecompile for Ed25519Verify {
+impl<A> LinearCostPrecompile for Ed25519Verify<A>
+where
+    A: From<[u8; 32]>,
+{
     const BASE: u64 = 15;
     const WORD: u64 = 3;
 
@@ -47,3 +52,21 @@ impl LinearCostPrecompile for Ed25519Verify {
         Ok((ExitSucceed::Returned, buf.to_vec()))
     }
 }
+
+/// Takes a slice from bytes with PrecompileFailure as Error
+fn parse_slice(data: &[u8], from: usize, to: usize) -> Result<&[u8], PrecompileFailure> {
+    let maybe_slice = data.get(from..to);
+    if let Some(slice) = maybe_slice {
+        Ok(slice)
+    } else {
+        log::error!(
+            "fail to get slice from data, {:?}, from {}, to {}",
+            &data,
+            from,
+            to
+        );
+        Err(PrecompileFailure::Error {
+            exit_status: ExitError::InvalidRange,
+        })
+    }
+}

precompiles/src/extensions.rs

@@ -0,0 +1,155 @@
+extern crate alloc;
+
+use alloc::format;
+
+use frame_support::dispatch::{GetDispatchInfo, Pays, PostDispatchInfo};
+use frame_system::RawOrigin;
+use pallet_evm::{
+    AddressMapping, BalanceConverter, ExitError, GasWeightMapping, PrecompileFailure,
+    PrecompileHandle,
+};
+use precompile_utils::EvmResult;
+use sp_core::{H160, U256, blake2_256};
+use sp_runtime::traits::Dispatchable;
+use sp_std::vec::Vec;
+
+pub(crate) trait PrecompileHandleExt: PrecompileHandle {
+    fn caller_account_id<R>(&self) -> R::AccountId
+    where
+        R: frame_system::Config + pallet_evm::Config,
+        <R as pallet_evm::Config>::AddressMapping: AddressMapping<R::AccountId>,
+    {
+        <R as pallet_evm::Config>::AddressMapping::into_account_id(self.context().caller)
+    }
+
+    fn try_convert_apparent_value<R>(&self) -> EvmResult<U256>
+    where
+        R: pallet_evm::Config,
+    {
+        let amount = self.context().apparent_value;
+        <R as pallet_evm::Config>::BalanceConverter::into_substrate_balance(amount).ok_or(
+            PrecompileFailure::Error {
+                exit_status: ExitError::Other(
+                    "error converting balance from ETH to subtensor".into(),
+                ),
+            },
+        )
+    }
+
+    /// Dispatches a runtime call, but also checks and records the gas costs.
+    fn try_dispatch_runtime_call<R, Call>(
+        &mut self,
+        call: Call,
+        origin: RawOrigin<R::AccountId>,
+    ) -> EvmResult<()>
+    where
+        R: frame_system::Config + pallet_evm::Config,
+        R::RuntimeCall: From<Call>,
+        R::RuntimeCall: GetDispatchInfo + Dispatchable<PostInfo = PostDispatchInfo>,
+        R::RuntimeOrigin: From<RawOrigin<R::AccountId>>,
+    {
+        let call = R::RuntimeCall::from(call);
+        let info = GetDispatchInfo::get_dispatch_info(&call);
+
+        let target_gas = self.gas_limit();
+        if let Some(gas) = target_gas {
+            let valid_weight =
+                <R as pallet_evm::Config>::GasWeightMapping::gas_to_weight(gas, false).ref_time();
+            if info.weight.ref_time() > valid_weight {
+                return Err(PrecompileFailure::Error {
+                    exit_status: ExitError::OutOfGas,
+                });
+            }
+        }
+
+        self.record_external_cost(
+            Some(info.weight.ref_time()),
+            Some(info.weight.proof_size()),
+            None,
+        )?;
+
+        match call.dispatch(R::RuntimeOrigin::from(origin)) {
+            Ok(post_info) => {
+                if post_info.pays_fee(&info) == Pays::Yes {
+                    let actual_weight = post_info.actual_weight.unwrap_or(info.weight);
+                    let cost =
+                        <R as pallet_evm::Config>::GasWeightMapping::weight_to_gas(actual_weight);
+                    self.record_cost(cost)?;
+
+                    self.refund_external_cost(
+                        Some(
+                            info.weight
+                                .ref_time()
+                                .saturating_sub(actual_weight.ref_time()),
+                        ),
+                        Some(
+                            info.weight
+                                .proof_size()
+                                .saturating_sub(actual_weight.proof_size()),
+                        ),
+                    );
+                }
+
+                log::info!("Dispatch succeeded. Post info: {:?}", post_info);
+
+                Ok(())
+            }
+            Err(e) => {
+                log::error!("Dispatch failed. Error: {:?}", e);
+                log::warn!("Returning error PrecompileFailure::Error");
+                Err(PrecompileFailure::Error {
+                    exit_status: ExitError::Other(
+                        format!("dispatch execution failed: {}", <&'static str>::from(e)).into(),
+                    ),
+                })
+            }
+        }
+    }
+}
+
+impl<T> PrecompileHandleExt for T where T: PrecompileHandle {}
+
+pub(crate) trait PrecompileExt<AccountId: From<[u8; 32]>> {
+    const INDEX: u64;
+
+    // ss58 public key i.e., the contract sends funds it received to the destination address from
+    // the method parameter.
+    fn account_id() -> AccountId {
+        let hash = H160::from_low_u64_be(Self::INDEX);
+        let prefix = b"evm:";
+
+        // Concatenate prefix and ethereum address
+        let mut combined = Vec::new();
+        combined.extend_from_slice(prefix);
+        combined.extend_from_slice(hash.as_bytes());
+
+        let hash = blake2_256(&combined);
+
+        hash.into()
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    use sp_core::crypto::AccountId32;
+
+    #[test]
+    fn ss58_address_from_index_works() {
+        assert_eq!(
+            TestPrecompile::account_id(),
+            AccountId32::from([
+                0x3a, 0x86, 0x18, 0xfb, 0xbb, 0x1b, 0xbc, 0x47, 0x86, 0x64, 0xff, 0x53, 0x46, 0x18,
+                0x0c, 0x35, 0xd0, 0x9f, 0xac, 0x26, 0xf2, 0x02, 0x70, 0x85, 0xb3, 0x1c, 0x56, 0xc1,
+                0x06, 0x3c, 0x1c, 0xd3,
+            ])
+        );
+    }
+
+    struct TestPrecompile;
+
+    impl PrecompileExt<AccountId32> for TestPrecompile {
+        const INDEX: u64 = 2051;
+    }
+}