helios/execution/src/execution.rs

use std::collections::HashMap;
use std::str::FromStr;

use ethers::abi::AbiEncode;
use ethers::prelude::{Address, U256};
use ethers::types::{TransactionReceipt, H256};
use ethers::utils::keccak256;
use ethers::utils::rlp::{encode, RlpStream};
use eyre::Result;

use common::utils::hex_str_to_bytes;
use consensus::types::ExecutionPayload;
use triehash_ethereum::ordered_trie_root;

use super::proof::{encode_account, verify_proof};
use super::rpc::Rpc;
use super::types::{Account, ExecutionBlock};

#[derive(Clone)]
pub struct ExecutionClient {
    rpc: Rpc,
}

impl ExecutionClient {
    pub fn new(rpc: &str) -> Self {
        let rpc = Rpc::new(rpc);
        ExecutionClient { rpc }
    }

    pub async fn get_account(
        &self,
        address: &Address,
        slots: Option<&[U256]>,
        payload: &ExecutionPayload,
    ) -> Result<Account> {
        let slots = slots.unwrap_or(&[]);

        let proof = self
            .rpc
            .get_proof(&address, slots, payload.block_number)
            .await?;

        let account_path = keccak256(address.as_bytes()).to_vec();
        let account_encoded = encode_account(&proof);

        let is_valid = verify_proof(
            &proof.account_proof,
            &payload.state_root,
            &account_path,
            &account_encoded,
        );

        if !is_valid {
            eyre::bail!("Invalid Proof");
        }

        let mut slot_map = HashMap::new();

        for storage_proof in proof.storage_proof {
            let key = hex_str_to_bytes(&storage_proof.key.encode_hex())?;
            let value = encode(&storage_proof.value).to_vec();

            let key_hash = keccak256(key);

            let is_valid = verify_proof(
                &storage_proof.proof,
                &proof.storage_hash.as_bytes().to_vec(),
                &key_hash.to_vec(),
                &value,
            );

            if !is_valid {
                eyre::bail!("Invalid Proof");
            }

            slot_map.insert(storage_proof.key, storage_proof.value);
        }

        Ok(Account {
            balance: proof.balance,
            nonce: proof.nonce,
            code_hash: proof.code_hash,
            storage_hash: proof.storage_hash,
            slots: slot_map,
        })
    }

    pub async fn get_code(&self, address: &Address, payload: &ExecutionPayload) -> Result<Vec<u8>> {
        let account = self.get_account(address, None, payload).await?;
        let code = self.rpc.get_code(address, payload.block_number).await?;

        let code_hash = keccak256(&code).into();

        if account.code_hash != code_hash {
            eyre::bail!("Invalid Proof");
        }

        Ok(code)
    }

    pub async fn send_raw_transaction(&self, bytes: &Vec<u8>) -> Result<Vec<u8>> {
        self.rpc.send_raw_transaction(bytes).await
    }

    pub fn get_block(&self, payload: &ExecutionPayload) -> Result<ExecutionBlock> {
        let empty_nonce = "0x0000000000000000".to_string();
        let empty_uncle_hash = "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347";

        let txs = payload
            .transactions
            .iter()
            .map(|tx| H256::from_slice(&keccak256(tx.to_vec())))
            .collect::<Vec<H256>>();

        Ok(ExecutionBlock {
            number: payload.block_number,
            base_fee_per_gas: U256::from_little_endian(&payload.base_fee_per_gas.to_bytes_le()),
            difficulty: U256::from(0),
            extra_data: payload.extra_data.to_vec(),
            gas_limit: payload.gas_limit,
            gas_used: payload.gas_used,
            hash: H256::from_slice(&payload.block_hash),
            logs_bloom: payload.logs_bloom.to_vec(),
            miner: Address::from_slice(&payload.fee_recipient),
            parent_hash: H256::from_slice(&payload.parent_hash),
            receipts_root: H256::from_slice(&payload.receipts_root),
            state_root: H256::from_slice(&payload.state_root),
            timestamp: payload.timestamp,
            total_difficulty: 0,
            transactions: txs,
            mix_hash: H256::from_slice(&payload.prev_randao),
            nonce: empty_nonce,
            sha3_uncles: H256::from_str(empty_uncle_hash)?,
            size: 0,
            transactions_root: H256::default(),
            uncles: vec![],
        })
    }

    pub async fn get_transaction_receipt(
        &self,
        tx_hash: &Vec<u8>,
        payloads: &HashMap<u64, ExecutionPayload>,
    ) -> Result<Option<TransactionReceipt>> {

        let receipt = self.rpc.get_transaction_receipt(tx_hash).await?;
        if receipt.is_none() {
            return Ok(None);
        }

        let receipt = receipt.unwrap();
        let payload = payloads.get(&receipt.block_number.unwrap().as_u64());
        if payload.is_none() {
            return Ok(None);
        }

        let payload = payload.unwrap();

        let tx_hashes = payload
            .transactions
            .iter()
            .map(|tx| H256::from_slice(&keccak256(tx)))
            .collect::<Vec<H256>>();

        let mut receipts = vec![];
        for hash in tx_hashes {
            let receipt = self
                .rpc
                .get_transaction_receipt(&hash.as_bytes().to_vec())
                .await?
                .unwrap();

            receipts.push(receipt);
        }

        let receipts_encoded: Vec<Vec<u8>> = receipts
            .iter()
            .map(|receipt| encode_receipt(receipt))
            .collect();

        let expected_receipt_root = ordered_trie_root(receipts_encoded);
        let expected_receipt_root = H256::from_slice(&expected_receipt_root.to_fixed_bytes());
        let payload_receipt_root = H256::from_slice(&payload.receipts_root);

        if expected_receipt_root != payload_receipt_root || !receipts.contains(&receipt) {
            return Err(eyre::eyre!("Receipt Proof Invalid"));
        }

        Ok(Some(receipt))
    }
}

fn encode_receipt(receipt: &TransactionReceipt) -> Vec<u8> {
    let mut stream = RlpStream::new();
    stream.begin_list(4);
    stream.append(&receipt.status.unwrap());
    stream.append(&receipt.cumulative_gas_used);
    stream.append(&receipt.logs_bloom);
    stream.append_list(&receipt.logs);

    let legacy_receipt_encoded = stream.out();
    let tx_type = receipt.transaction_type.unwrap().as_u64();

    match tx_type {
        0 => legacy_receipt_encoded.to_vec(),
        _ => [&tx_type.to_be_bytes()[7..8], &legacy_receipt_encoded].concat(),
    }
}