[WIP] Add a flashloan and make contract callable by anyone

README.md

@@ -2,6 +2,10 @@ simple-arbitrage
 ================
 This repository contains a simple, mechanical system for discovering, evaluating, rating, and submitting arbitrage opportunities to the Flashbots bundle endpoint. This script is very unlikely to be profitable, as many users have access to it, and it is targeting well-known Ethereum opportunities.
 
+simple-arbitrage uses Flashloans to source liquidity to execute on arbitrage opportunities it finds. It attempts to capture them and sends any profits made, net of fees, back to the message sender. We have deployed a contract that anyone can submit trades to here:
+
+You do not need any Ethereum to use this contract.
+
 We hope you will use this repository as an example of how to integrate Flashbots into your own Flashbot searcher (bot). For more information, see the [Flashbots Searcher FAQ](https://github.com/flashbots/pm/blob/main/guides/searcher-onboarding.md)
 
 Environment Variables
@@ -15,15 +19,12 @@ Environment Variables
 Usage
 ======================
 1. Generate a new bot wallet address and extract the private key into a raw 32-byte format.
-2. Deploy the included BundleExecutor.sol to Ethereum, from a secured account, with the address of the newly created wallet as the constructor argument
-3. Transfer WETH to the newly deployed BundleExecutor
-
-_It is important to keep both the bot wallet private key and bundleExecutor owner private key secure. The bot wallet attempts to not lose WETH inside an arbitrage, but a malicious user would be able to drain the contract._
+2. Run simple-arbitage using the new private key from step (1) as an environment varaible.
 
 ```
 $ npm install
-$ PRIVATE_KEY=__PRIVATE_KEY_FROM_ABOVE__ \
-    BUNDLE_EXECUTOR_ADDRESS=__DEPLOYED_ADDRESS_FROM_ABOVE__ \
+$ ETHEREUM_RPC_URL=__ETHEREUM_RPC_URL_FROM_ABOVE__ \
+    PRIVATE_KEY=__PRIVATE_KEY_FROM_ABOVE__ \
     FLASHBOTS_RELAY_SIGNING_KEY=__RANDOM_ETHEREUM_PRIVATE_KEY__ \
       npm run start
 ```

contracts/BundleExecutor.sol

@@ -1,81 +1,99 @@
 //SPDX-License-Identifier: UNLICENSED
 pragma solidity 0.6.12;
-
 pragma experimental ABIEncoderV2;
 
-interface IERC20 {
-    event Approval(address indexed owner, address indexed spender, uint value);
-    event Transfer(address indexed from, address indexed to, uint value);
-
-    function name() external view returns (string memory);
-    function symbol() external view returns (string memory);
-    function decimals() external view returns (uint8);
-    function totalSupply() external view returns (uint);
-    function balanceOf(address owner) external view returns (uint);
-    function allowance(address owner, address spender) external view returns (uint);
-
-    function approve(address spender, uint value) external returns (bool);
-    function transfer(address to, uint value) external returns (bool);
-    function transferFrom(address from, address to, uint value) external returns (bool);
-}
+import "./FlashLoanReceiverBase.sol";
+import "./Interfaces.sol";
+import "./Libraries.sol";
 
 interface IWETH is IERC20 {
     function deposit() external payable;
     function withdraw(uint) external;
 }
 
-// This contract simply calls multiple targets sequentially, ensuring WETH balance before and after
-
-contract FlashBotsMultiCall {
-    address private immutable owner;
-    address private immutable executor;
-    IWETH private constant WETH = IWETH(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
+contract FlashBotsMultiCallFL is FlashLoanReceiverBase {
+    using SafeMath for uint256;
+    address public constant WETH_address = address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
+    IWETH private constant WETH = IWETH(WETH_address);
 
-    modifier onlyExecutor() {
-        require(msg.sender == executor);
-        _;
+    constructor(ILendingPoolAddressesProvider _addressProvider) FlashLoanReceiverBase(_addressProvider) public payable {
+        WETH.approve(address(LENDING_POOL), uint(-1));
     }
 
-    modifier onlyOwner() {
-        require(msg.sender == owner);
-        _;
-    }
+    /**
+        This function is called after your contract has received the flash loaned amount
+     */
+    function executeOperation(
+        address[] calldata assets,
+        uint256[] calldata amounts,
+        uint256[] calldata premiums,
+        address initiator,
+        bytes calldata params
+    )
+        external
+        override
+        returns (bool)
+    {
+        uint aaveDebt = amounts[0].add(premiums[0]);
+        uniswapWethFLParams(amounts[0], params, aaveDebt);
 
-    constructor(address _executor) public payable {
-        owner = msg.sender;
-        executor = _executor;
-        if (msg.value > 0) {
-            WETH.deposit{value: msg.value}();
-        }
+        return true;
     }
 
-    receive() external payable {
+    function flashloan(uint256 amountToBorrow, bytes memory _params) external {
+        address receiverAddress = address(this);
+
+        address[] memory assets = new address[](1);
+        assets[0] = WETH_address;
+
+        uint256[] memory amounts = new uint256[](1);
+        amounts[0] = amountToBorrow;
+
+        uint256[] memory modes = new uint256[](1);
+        modes[0] = 0;
+
+        address onBehalfOf = address(this);
+        uint16 referralCode = 161;
+
+        LENDING_POOL.flashLoan(
+            receiverAddress,
+            assets,
+            amounts,
+            modes,
+            onBehalfOf,
+            _params,
+            referralCode
+        );
     }
 
-    function uniswapWeth(uint256 _wethAmountToFirstMarket, uint256 _ethAmountToCoinbase, address[] memory _targets, bytes[] memory _payloads) external onlyExecutor payable {
-        require (_targets.length == _payloads.length);
-        uint256 _wethBalanceBefore = WETH.balanceOf(address(this));
-        WETH.transfer(_targets[0], _wethAmountToFirstMarket);
+    function uniswapWethFLParams(uint256 _amountToFirstMarket, bytes memory _params, uint256 aaveDebt) internal {
+        (uint256 _ethAmountToCoinbase, address[] memory _targets, bytes[] memory _payloads) = abi.decode(_params, (uint256, address[], bytes[]));
+        require(_targets.length == _payloads.length);
+
+        WETH.transfer(_targets[0], _amountToFirstMarket);
         for (uint256 i = 0; i < _targets.length; i++) {
             (bool _success, bytes memory _response) = _targets[i].call(_payloads[i]);
-            require(_success); _response;
+            require(_success); 
         }
 
         uint256 _wethBalanceAfter = WETH.balanceOf(address(this));
-        require(_wethBalanceAfter > _wethBalanceBefore + _ethAmountToCoinbase);
-        if (_ethAmountToCoinbase == 0) return;
 
-        uint256 _ethBalance = address(this).balance;
-        if (_ethBalance < _ethAmountToCoinbase) {
-            WETH.withdraw(_ethAmountToCoinbase - _ethBalance);
-        }
+        uint256 _profit = _wethBalanceAfter - aaveDebt - _ethAmountToCoinbase;
+
+        require(_profit >= 0);
+
+        WETH.withdraw(_ethAmountToCoinbase + _profit);
         block.coinbase.transfer(_ethAmountToCoinbase);
+        tx.origin.transfer(_profit);
     }
 
-    function call(address payable _to, uint256 _value, bytes calldata _data) external onlyOwner payable returns (bytes memory) {
+    function call(address payable _to, uint256 _value, bytes calldata _data) external payable returns (bytes memory) {
         require(_to != address(0));
         (bool _success, bytes memory _result) = _to.call{value: _value}(_data);
         require(_success);
         return _result;
     }
+
+    receive() external payable {
+    }
 }

contracts/BundleExecutorNoFlashloan.sol

@@ -0,0 +1,81 @@
+//SPDX-License-Identifier: UNLICENSED
+pragma solidity 0.6.12;
+
+pragma experimental ABIEncoderV2;
+
+interface IERC20 {
+    event Approval(address indexed owner, address indexed spender, uint value);
+    event Transfer(address indexed from, address indexed to, uint value);
+
+    function name() external view returns (string memory);
+    function symbol() external view returns (string memory);
+    function decimals() external view returns (uint8);
+    function totalSupply() external view returns (uint);
+    function balanceOf(address owner) external view returns (uint);
+    function allowance(address owner, address spender) external view returns (uint);
+
+    function approve(address spender, uint value) external returns (bool);
+    function transfer(address to, uint value) external returns (bool);
+    function transferFrom(address from, address to, uint value) external returns (bool);
+}
+
+interface IWETH is IERC20 {
+    function deposit() external payable;
+    function withdraw(uint) external;
+}
+
+// This contract simply calls multiple targets sequentially, ensuring WETH balance before and after
+
+contract FlashBotsMultiCall {
+    address private immutable owner;
+    address private immutable executor;
+    IWETH private constant WETH = IWETH(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
+
+    modifier onlyExecutor() {
+        require(msg.sender == executor);
+        _;
+    }
+
+    modifier onlyOwner() {
+        require(msg.sender == owner);
+        _;
+    }
+
+    constructor(address _executor) public payable {
+        owner = msg.sender;
+        executor = _executor;
+        if (msg.value > 0) {
+            WETH.deposit{value: msg.value}();
+        }
+    }
+
+    receive() external payable {
+    }
+
+    function uniswapWeth(uint256 _wethAmountToFirstMarket, uint256 _ethAmountToCoinbase, address[] memory _targets, bytes[] memory _payloads) external onlyExecutor payable {
+        require (_targets.length == _payloads.length);
+        uint256 _wethBalanceBefore = WETH.balanceOf(address(this));
+        WETH.transfer(_targets[0], _wethAmountToFirstMarket);
+        for (uint256 i = 0; i < _targets.length; i++) {
+            (bool _success, bytes memory _response) = _targets[i].call(_payloads[i]);
+            require(_success); _response;
+        }
+
+        uint256 _wethBalanceAfter = WETH.balanceOf(address(this));
+        require(_wethBalanceAfter > _wethBalanceBefore + _ethAmountToCoinbase);
+        if (_ethAmountToCoinbase == 0) return;
+
+        uint256 _ethBalance = address(this).balance;
+        if (_ethBalance < _ethAmountToCoinbase) {
+            WETH.withdraw(_ethAmountToCoinbase - _ethBalance);
+        }
+        block.coinbase.transfer(_ethAmountToCoinbase);
+    }
+
+    function call(address payable _to, uint256 _value, bytes calldata _data) external onlyOwner payable returns (bytes memory) {
+        require(_to != address(0));
+        (bool _success, bytes memory _result) = _to.call{value: _value}(_data);
+        require(_success);
+        return _result;
+    }
+}

contracts/FlashLoanReceiverBase.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: agpl-3.0
+pragma solidity 0.6.12;
+
+import "./Interfaces.sol";
+import "./Libraries.sol";
+
+abstract contract FlashLoanReceiverBase is IFlashLoanReceiver {
+  using SafeERC20 for IERC20;
+  using SafeMath for uint256;
+
+  ILendingPoolAddressesProvider public immutable ADDRESSES_PROVIDER;
+  ILendingPool public immutable LENDING_POOL;
+
+  constructor(ILendingPoolAddressesProvider provider) public {
+    ADDRESSES_PROVIDER = provider;
+    LENDING_POOL = ILendingPool(provider.getLendingPool());
+  }
+}