《惊魂记》与MEV攻击：浴室场景的链上抢跑隐喻

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "@openzeppelin/contracts/access/AccessControl.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

contract MEVShield is AccessControl, ReentrancyGuard {
    bytes32 public constant RELAYER_ROLE = keccak256("RELAYER_ROLE");
    bytes32 public constant USER_ROLE = keccak256("USER_ROLE");

    enum MEVAttackType {
        FRONTRUNNING, SANDBWICH, BACKRUNNING, DISPLACEMENT, TIMEBANDIT
    }

    struct Transaction {
        bytes32 txHash;
        address sender;
        address target;
        uint256 value;
        bytes data;
        uint256 gasPrice;
        uint256 nonce;
        uint256 timestamp;
        bool isProtected;
    }

    struct MEVAttack {
        uint256 attackId;
        bytes32 victimTxHash;
        address attacker;
        MEVAttackType attackType;
        uint256 profitAmount;
        uint256 victimLoss;
        uint256 blockNumber;
        uint256 timestamp;
        bool isDetected;
    }

    struct ProtectionStrategy {
        uint256 strategyId;
        string name;
        uint256 maxSlippage;
        uint256 minProfitThreshold;
        uint256 commitRevealDelay;
        bool isActive;
    }

    mapping(bytes32 => Transaction) public transactions;
    mapping(uint256 => MEVAttack) public attacks;
    mapping(address => ProtectionStrategy) public userStrategies;
    mapping(address => uint256) public totalLosses;
    mapping(address => uint256) public totalProtected;

    uint256 public attackCount;
    uint256 public totalProfitExtracted;
    uint256 public totalLossPrevented;
    uint256 public protectionThreshold = 1000 ether;

    event AttackDetected(
        uint256 indexed attackId,
        address indexed attacker,
        bytes32 indexed victimTxHash,
        MEVAttackType attackType,
        uint256 profit
    );

    event TransactionProtected(
        bytes32 indexed txHash,
        address indexed user,
        uint256 savedAmount
    );

    function submitTransaction(
        address _target,
        uint256 _value,
        bytes calldata _data,
        uint256 _gasPrice
    ) external onlyRole(USER_ROLE) returns (bytes32) {
        bytes32 txHash = keccak256(abi.encodePacked(
            msg.sender, _target, _value, _data, _gasPrice, block.timestamp
        ));

        transactions[txHash] = Transaction({
            txHash: txHash,
            sender: msg.sender,
            target: _target,
            value: _value,
            data: _data,
            gasPrice: _gasPrice,
            nonce: nonce,
            timestamp: block.timestamp,
            isProtected: true
        });

        emit TransactionProtected(txHash, msg.sender, _value);
        return txHash;
    }

    function detectAttack(
        bytes32 _victimTxHash,
        address _attacker,
        MEVAttackType _attackType,
        uint256 _profitAmount
    ) external onlyRole(RELAYER_ROLE) returns (uint256) {
        attackCount++;
        uint256 victimLoss = _profitAmount * 3 / 2;

        attacks[attackCount] = MEVAttack({
            attackId: attackCount,
            victimTxHash: _victimTxHash,
            attacker: _attacker,
            attackType: _attackType,
            profitAmount: _profitAmount,
            victimLoss: victimLoss,
            blockNumber: block.number,
            timestamp: block.timestamp,
            isDetected: true
        });

        totalProfitExtracted += _profitAmount;
        totalLossPrevented += victimLoss;

        emit AttackDetected(attackCount, _attacker, _victimTxHash, _attackType, _profitAmount);
        return attackCount;
    }

    function getProtectionStatus(address _user) external view returns (bool) {
        return userStrategies[_user].isActive;
    }
}

import asyncio
import aiohttp
from web3 import Web3
from typing import Dict, List, Tuple, Optional
from dataclasses import dataclass
from datetime import datetime
import json

@dataclass
class MempoolTransaction:
    tx_hash: str
    from_addr: str
    to_addr: str
    value: int
    gas_price: int
    gas_limit: int
    nonce: int
    data: bytes
    timestamp: int

class MEVMonitor:
    def __init__(self, rpc_url: str, flashbots_url: str):
        self.w3 = Web3(Web3.HTTPProvider(rpc_url))
        self.flashbots_url = flashbots_url
        self.mempool_txs: Dict[str, MempoolTransaction] = {}
        self.attack_patterns: Dict[str, List[Dict]] = {}
        self.profit_threshold = Web3.to_wei(0.1, 'ether')

    async def scan_mempool(self) -> List[MempoolTransaction]:
        pending = self.w3.eth.get_block('pending', full_transactions=True)
        txs = []
        for tx in pending.transactions:
            mempool_tx = MempoolTransaction(
                tx_hash=tx.hash.hex(),
                from_addr=tx['from'],
                to_addr=tx['to'],
                value=tx['value'],
                gas_price=tx['gasPrice'],
                gas_limit=tx['gas'],
                nonce=tx['nonce'],
                data=tx['input'],
                timestamp=int(datetime.now().timestamp())
            )
            txs.append(mempool_tx)
            self.mempool_txs[tx.hash.hex()] = mempool_tx
        return txs

    def detect_sandwich_opportunity(self, tx: MempoolTransaction) -> Optional[Dict]:
        if tx.value < self.profit_threshold:
            return None

        potential_profit = tx.value * 5 // 1000
        if potential_profit < self.profit_threshold:
            return None

        return {
            'victim_tx': tx.tx_hash,
            'target': tx.to_addr,
            'estimated_profit': potential_profit,
            'gas_price_buffer': tx.gas_price * 2,
            'timestamp': tx.timestamp
        }

    async def submit_flashbots_bundle(self, bundle: List[Dict]) -> bool:
        async with aiohttp.ClientSession() as session:
            payload = {
                'jsonrpc': '2.0',
                'method': 'eth_sendBundle',
                'params': [{
                    'txs': [tx['signed_tx'] for tx in bundle],
                    'blockNumber': hex(self.w3.eth.block_number + 1),
                    'minTimestamp': 0,
                    'maxTimestamp': bundle[-1]['timestamp'] + 30
                }],
                'id': 1
            }
            async with session.post(self.flashbots_url, json=payload) as resp:
                result = await resp.json()
                return 'error' not in result

    def calculate_mev_score(self, address: str) -> Dict:
        score = 0
        metrics = {
            'total_frontruns': 0,
            'total_sandwiches': 0,
            'total_profit': 0,
            'total_gas_spent': 0,
            'unique_victims': set()
        }
        return {'score': score, 'metrics': metrics}

    async def run(self):
        while True:
            try:
                txs = await self.scan_mempool()
                for tx in txs:
                    opportunity = self.detect_sandwich_opportunity(tx)
                    if opportunity:
                        print(f"Potential sandwich on {tx.tx_hash[:10]}...")
                await asyncio.sleep(1)
            except Exception as e:
                print(f"Scan error: {e}")
                await asyncio.sleep(5)

monitor = MEVMonitor(
    rpc_url="https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY",
    flashbots_url="https://relay.flashbots.net"
)
asyncio.run(monitor.run())

const { ethers } = require('ethers');
const { FlashbotsBundleProvider } = require('@flashbots/ethers-provider-bundle');

class MEVShieldClient {
  constructor(providerUrl, flashbotsRelayUrl, authSigner) {
    this.provider = new ethers.providers.JsonRpcProvider(providerUrl);
    this.flashbotsProvider = FlashbotsBundleProvider.create(
      this.provider,
      authSigner,
      flashbotsRelayUrl,
      'mainnet'
    );
    this.pendingTxs = new Map();
    this.protectionQueue = [];
  }

  async monitorPendingTransactions() {
    this.provider.on('pending', async (txHash) => {
      try {
        const tx = await this.provider.getTransaction(txHash);
        if (tx && tx.value.gt(ethers.utils.parseEther('0.1'))) {
          this.pendingTxs.set(txHash, {
            hash: txHash,
            from: tx.from,
            to: tx.to,
            value: tx.value,
            gasPrice: tx.gasPrice,
            nonce: tx.nonce,
            timestamp: Date.now()
          });
          await this.analyzeProtection(txHash);
        }
      } catch (error) {
        console.error('Monitor error:', error.message);
      }
    });
  }

  async analyzeProtection(txHash) {
    const tx = this.pendingTxs.get(txHash);
    if (!tx) return;

    const riskScore = this.calculateRiskScore(tx);
    if (riskScore > 70) {
      this.protectionQueue.push({
        txHash,
        riskScore,
        timestamp: Date.now()
      });
      await this.applyProtection(txHash);
    }
  }

  calculateRiskScore(tx) {
    let score = 0;
    if (tx.value.gt(ethers.utils.parseEther('10'))) score += 30;
    if (tx.gasPrice.gt(ethers.utils.parseUnits('50', 'gwei'))) score += 20;
    if (tx.to && tx.to.toLowerCase() === '0x7a250d5630b4cf539739df2c5dacb4c659f2488d') {
      score += 25;
    }
    if (this.hasRecentRelatedTxs(tx.from)) score += 15;
    return score;
  }

  hasRecentRelatedTxs(address) {
    let count = 0;
    const fiveMinutesAgo = Date.now() - 300000;
    for (const [hash, tx] of this.pendingTxs) {
      if (tx.from === address && tx.timestamp > fiveMinutesAgo) {
        count++;
      }
    }
    return count > 3;
  }

  async applyProtection(txHash) {
    try {
      const bundle = await this.flashbotsProvider.signBundle([
        {
          signedTransaction: txHash
        }
      ]);
      const blockNumber = await this.provider.getBlockNumber();
      const targetBlock = blockNumber + 1;
      const simulation = await this.flashbotsProvider.simulate(bundle, targetBlock);
      if (simulation.firstRevert === undefined) {
        const submission = await this.flashbotsProvider.sendBundle(bundle, targetBlock);
        console.log(`Protected ${txHash.slice(0, 10)}... in block ${targetBlock}`);
        return true;
      }
    } catch (error) {
      console.error('Protection error:', error.message);
      return false;
    }
  }

  async getMEVStats(address) {
    const stats = {
      totalProtected: 0,
      totalSaved: ethers.BigNumber.from(0),
      attacksDetected: 0,
      lastAttack: null
    };
    return stats;
  }

  start() {
    this.monitorPendingTransactions();
    setInterval(() => this.cleanupOldTxs(), 60000);
  }

  cleanupOldTxs() {
    const fiveMinutesAgo = Date.now() - 300000;
    for (const [hash, tx] of this.pendingTxs) {
      if (tx.timestamp < fiveMinutesAgo) {
        this.pendingTxs.delete(hash);
      }
    }
  }
}

const provider = new ethers.providers.JsonRpcProvider('https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY');
const authSigner = new ethers.Wallet('YOUR_PRIVATE_KEY');
const shield = new MEVShieldClient(provider, 'https://relay.flashbots.net', authSigner);
shield.start();