Merge pull request #20 from propeller-heads/router/tnl/ENG-4043-delegate-call-executor

feat: delegatecall to executor in SwapExecutionDispatcher

foundry/interfaces/ISwapExecutor.sol

@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.28;
+
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+pragma abicoder v2;
+
+interface ISwapExecutor {
+    /**
+     * @notice Performs a swap on a liquidity pool.
+     * @dev This method takes the amount of the input token and returns the amount of
+     * the output token which has been swapped.
+     *
+     * Note Part of the informal interface is that the executor supports sending the received
+     *  tokens to a receiver address. If the underlying smart contract does not provide this
+     *  functionality consider adding an additional transfer in the implementation.
+     *
+     * @param givenAmount The amount of the input token to swap.
+     * @param data Data that holds information necessary to perform the swap.
+     * @return calculatedAmount The amount of the output token swapped, depending on
+     * the givenAmount inputted.
+     */
+    function swap(uint256 givenAmount, bytes calldata data)
+        external
+        returns (uint256 calculatedAmount);
+}
+
+interface ISwapExecutorErrors {
+    error InvalidParameterLength(uint256);
+    error UnknownPoolType(uint8);
+}

foundry/remappings.txt

@@ -1,3 +1,4 @@
 @openzeppelin/=lib/openzeppelin-contracts/
+@interfaces/=interfaces/
 @permit2/=lib/permit2/
 @src/=src/

foundry/src/SwapExecutionDispatcher.sol

@@ -1,6 +1,11 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.28;
 
+import "@interfaces/ISwapExecutor.sol";
+
+error SwapExecutionDispatcher__UnapprovedExecutor();
+error SwapExecutionDispatcher__NonContractExecutor();
+
 /**
  * @title SwapExecutionDispatcher - Dispatch swap execution to external contracts
  * @author PropellerHeads Devs
@@ -10,8 +15,88 @@ pragma solidity ^0.8.28;
  *  be called using delegatecall so they can share state with the main
  *  contract if needed.
  *
- *  Note Executor contracts need to implement the ISwapExecutor interface
+ *  Note Executor contracts need to implement the ISwapExecutor interface unless
+ *  an alternate selector is specified.
  */
 contract SwapExecutionDispatcher {
     mapping(address => bool) public swapExecutors;
+
+    event ExecutorSet(address indexed executor);
+    event ExecutorRemoved(address indexed executor);
+
+    /**
+     * @dev Adds or replaces an approved swap executor contract address if it is a
+     *  contract.
+     * @param target address of the swap executor contract
+     */
+    function _setSwapExecutor(address target) internal {
+        if (target.code.length == 0) {
+            revert SwapExecutionDispatcher__NonContractExecutor();
+        }
+        swapExecutors[target] = true;
+        emit ExecutorSet(target);
+    }
+
+    /**
+     * @dev Removes an approved swap executor contract address
+     * @param target address of the swap executor contract
+     */
+    function _removeSwapExecutor(address target) internal {
+        delete swapExecutors[target];
+        emit ExecutorRemoved(target);
+    }
+
+    /**
+     * @dev Calls an executor, assumes swap.protocolData contains
+     *  protocol-specific data required by the executor.
+     */
+    // slither-disable-next-line dead-code
+    function _callSwapExecutor(uint256 amount, bytes calldata data)
+        internal
+        returns (uint256 calculatedAmount)
+    {
+        address executor;
+        bytes4 decodedSelector;
+        bytes memory protocolData;
+
+        (executor, decodedSelector, protocolData) =
+            _decodeExecutorAndSelector(data);
+
+        if (!swapExecutors[executor]) {
+            revert SwapExecutionDispatcher__UnapprovedExecutor();
+        }
+
+        bytes4 selector = decodedSelector == bytes4(0)
+            ? ISwapExecutor.swap.selector
+            : decodedSelector;
+
+        // slither-disable-next-line low-level-calls
+        (bool success, bytes memory result) = executor.delegatecall(
+            abi.encodeWithSelector(selector, amount, protocolData)
+        );
+
+        if (!success) {
+            revert(
+                string(
+                    result.length > 0
+                        ? result
+                        : abi.encodePacked("Swap execution failed")
+                )
+            );
+        }
+
+        calculatedAmount = abi.decode(result, (uint256));
+    }
+
+    // slither-disable-next-line dead-code
+    function _decodeExecutorAndSelector(bytes calldata data)
+        internal
+        pure
+        returns (address executor, bytes4 selector, bytes memory protocolData)
+    {
+        require(data.length >= 24, "Invalid data length");
+        executor = address(uint160(bytes20(data[:20])));
+        selector = bytes4(data[20:24]);
+        protocolData = data[24:];
+    }
 }

foundry/src/TychoRouter.sol

@@ -10,7 +10,6 @@ import "./CallbackVerificationDispatcher.sol";
 
 error TychoRouter__WithdrawalFailed();
 error TychoRouter__AddressZero();
-error TychoRouter__NonContractExecutor();
 error TychoRouter__NonContractVerifier();
 
 contract TychoRouter is
@@ -45,7 +44,6 @@ contract TychoRouter is
         address indexed oldFeeReceiver, address indexed newFeeReceiver
     );
     event FeeSet(uint256 indexed oldFee, uint256 indexed newFee);
-    event ExecutorSet(address indexed executor);
     event CallbackVerifierSet(address indexed callbackVerifier);
 
     constructor(address _permit2) {
@@ -95,26 +93,24 @@ contract TychoRouter is
 
     /**
      * @dev Entrypoint to add or replace an approved swap executor contract address
-     * @param target address of the swap method contract
+     * @param target address of the swap executor contract
      */
     function setSwapExecutor(address target)
         external
         onlyRole(EXECUTOR_SETTER_ROLE)
     {
-        if (target.code.length == 0) revert TychoRouter__NonContractExecutor();
+        _setSwapExecutor(target);
-        swapExecutors[target] = true;
-        emit ExecutorSet(target);
     }
 
     /**
      * @dev Entrypoint to remove an approved swap executor contract address
-     * @param target address of the swap method contract
+     * @param target address of the swap executor contract
      */
     function removeSwapExecutor(address target)
         external
         onlyRole(EXECUTOR_SETTER_ROLE)
     {
-        delete swapExecutors[target];
+        _removeSwapExecutor(target);
     }
 
     /**

foundry/test/Constants.sol

@@ -8,7 +8,18 @@ contract Constants is Test {
     address BOB = makeAddr("bob"); //bob=someone!=us
     address FUND_RESCUER = makeAddr("fundRescuer");
     address FEE_SETTER = makeAddr("feeSetter");
+    address FEE_RECEIVER = makeAddr("feeReceiver");
+
     // dummy contracts
     address DUMMY = makeAddr("dummy");
-    address FEE_RECEIVER = makeAddr("feeReceiver");
+
+    address WETH_ADDR = address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
+
+    /**
+     * @dev Deploys a dummy contract with non-empty bytecode
+     */
+    function deployDummyContract() internal {
+        bytes memory minimalBytecode = hex"01"; // Single-byte bytecode
+        vm.etch(DUMMY, minimalBytecode); // Deploy minimal bytecode
+    }
 }

foundry/test/SwapExecutionDispatcher.t.sol

@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.28;
+
+import "@src/SwapExecutionDispatcher.sol";
+import "./TychoRouterTestSetup.sol";
+
+contract SwapExecutionDispatcherExposed is SwapExecutionDispatcher {
+    function exposedCallSwapExecutor(uint256 amount, bytes calldata data)
+        external
+        returns (uint256 calculatedAmount)
+    {
+        return _callSwapExecutor(amount, data);
+    }
+
+    function exposedDecodeExecutorAndSelector(bytes calldata data)
+        external
+        pure
+        returns (address executor, bytes4 selector, bytes memory protocolData)
+    {
+        return _decodeExecutorAndSelector(data);
+    }
+
+    function exposedSetSwapExecutor(address target) external {
+        _setSwapExecutor(target);
+    }
+
+    function exposedRemoveSwapExecutor(address target) external {
+        _removeSwapExecutor(target);
+    }
+}
+
+contract SwapExecutionDispatcherTest is Constants {
+    SwapExecutionDispatcherExposed dispatcherExposed;
+
+    event ExecutorSet(address indexed executor);
+    event ExecutorRemoved(address indexed executor);
+
+    function setUp() public {
+        uint256 forkBlock = 20673900;
+        vm.createSelectFork(vm.rpcUrl("mainnet"), forkBlock);
+        dispatcherExposed = new SwapExecutionDispatcherExposed();
+        deal(WETH_ADDR, address(dispatcherExposed), 15 ether);
+        deployDummyContract();
+    }
+
+    function testSetValidExecutor() public {
+        vm.expectEmit();
+        // Define the event we expect to be emitted at the next step
+        emit ExecutorSet(DUMMY);
+        dispatcherExposed.exposedSetSwapExecutor(DUMMY);
+        assert(dispatcherExposed.swapExecutors(DUMMY) == true);
+    }
+
+    function testRemoveExecutor() public {
+        dispatcherExposed.exposedSetSwapExecutor(DUMMY);
+        vm.expectEmit();
+        // Define the event we expect to be emitted at the next step
+        emit ExecutorRemoved(DUMMY);
+        dispatcherExposed.exposedRemoveSwapExecutor(DUMMY);
+        assert(dispatcherExposed.swapExecutors(DUMMY) == false);
+    }
+
+    function testRemoveUnSetExecutor() public {
+        dispatcherExposed.exposedRemoveSwapExecutor(BOB);
+        assert(dispatcherExposed.swapExecutors(BOB) == false);
+    }
+
+    function testSetExecutorNonContract() public {
+        vm.expectRevert(
+            abi.encodeWithSelector(
+                SwapExecutionDispatcher__NonContractExecutor.selector
+            )
+        );
+        dispatcherExposed.exposedSetSwapExecutor(BOB);
+    }
+
+    function testCallSwapExecutor() public {
+        // Test case taken from existing transaction
+        // 0x755d603962b30f416cf3eefae8d55204d6ffdf746465b2a94aca216faab63804
+        // For this test, we can use any executor and any calldata that we know works
+        // for this executor. We don't care about which calldata/executor, since we are
+        // only testing the functionality of the delegatecall and not the inner
+        // workings of the executor.
+        // Thus, we chose a previously-deployed Hashflow executor for simplicity. To
+        // change this test, we can find any of our transactions that succeeded, and
+        // obtain the calldata passed to the executor via Tenderly.
+        dispatcherExposed.exposedSetSwapExecutor(
+            address(0xe592557AB9F4A75D992283fD6066312FF013ba3d)
+        );
+        bytes memory data =
+            hex"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";
+        uint256 givenAmount = 15 ether;
+        uint256 amount =
+            dispatcherExposed.exposedCallSwapExecutor(givenAmount, data);
+        assert(amount == 35144641819);
+    }
+
+    function testCallSwapExecutorNoSelector() public {
+        // Test case taken from existing transaction
+        // 0x755d603962b30f416cf3eefae8d55204d6ffdf746465b2a94aca216faab63804
+        // No selector is passed, so the standard swap selector should be used
+
+        // For this test, we can use any executor and any calldata that we know works
+        // for this executor. We don't care about which calldata/executor, since we are
+        // only testing the functionality of the delegatecall and not the inner
+        // workings of the executor.
+        // Thus, we chose a previously-deployed Hashflow executor for simplicity. To
+        // change this test, we can find any of our transactions that succeeded, and
+        // obtain the calldata passed to the executor via Tenderly.
+        dispatcherExposed.exposedSetSwapExecutor(
+            address(0xe592557AB9F4A75D992283fD6066312FF013ba3d)
+        );
+        bytes memory data =
+            hex"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";
+        uint256 givenAmount = 15 ether;
+        uint256 amount =
+            dispatcherExposed.exposedCallSwapExecutor(givenAmount, data);
+        assert(amount == 35144641819);
+    }
+
+    function testCallSwapExecutorCallFailed() public {
+        // Bad data is provided to an approved swap executor - causing the call to fail
+        dispatcherExposed.exposedSetSwapExecutor(
+            address(0xe592557AB9F4A75D992283fD6066312FF013ba3d)
+        );
+        bytes memory data =
+            hex"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";
+        vm.expectRevert();
+        dispatcherExposed.exposedCallSwapExecutor(0, data);
+    }
+
+    function testCallSwapExecutorUnapprovedExecutor() public {
+        bytes memory data =
+            hex"5d622C9053b8FFB1B3465495C8a42E603632bA70aabbccdd1111111111111111";
+        vm.expectRevert();
+        dispatcherExposed.exposedCallSwapExecutor(0, data);
+    }
+
+    function testDecodeExecutorAndSelector() public {
+        bytes memory data =
+            hex"6611e616d2db3244244a54c754a16dd3ac7ca7a2aabbccdd1111111111111111";
+        (address executor, bytes4 selector, bytes memory protocolData) =
+            dispatcherExposed.exposedDecodeExecutorAndSelector(data);
+        assert(executor == address(0x6611e616d2db3244244A54c754A16dd3ac7cA7a2));
+        assert(selector == bytes4(0xaabbccdd));
+        // Direct bytes comparison not supported - must use keccak
+        assert(keccak256(protocolData) == keccak256(hex"1111111111111111"));
+    }
+}

foundry/test/TychoRouter.t.sol

@@ -14,39 +14,18 @@ contract TychoRouterTest is TychoRouterTestSetup {
     bytes32 public constant FUND_RESCUER_ROLE =
         0x912e45d663a6f4cc1d0491d8f046e06c616f40352565ea1cdb86a0e1aaefa41b;
 
-    event ExecutorSet(address indexed executor);
     event CallbackVerifierSet(address indexed callbackVerifier);
     event Withdrawal(
         address indexed token, uint256 amount, address indexed receiver
     );
 
-    function testSetValidExecutor() public {
+    function testSetExecutorValidRole() public {
         vm.startPrank(executorSetter);
-        vm.expectEmit();
-        // Define the event we expect to be emitted at the next step
-        emit ExecutorSet(DUMMY);
-
         tychoRouter.setSwapExecutor(DUMMY);
         vm.stopPrank();
-
         assert(tychoRouter.swapExecutors(DUMMY) == true);
     }
 
-    function testRemoveExecutor() public {
-        vm.startPrank(executorSetter);
-        tychoRouter.setSwapExecutor(DUMMY);
-        tychoRouter.removeSwapExecutor(DUMMY);
-        vm.stopPrank();
-        assert(tychoRouter.swapExecutors(DUMMY) == false);
-    }
-
-    function testRemoveUnSetExecutor() public {
-        vm.startPrank(executorSetter);
-        tychoRouter.removeSwapExecutor(BOB);
-        vm.stopPrank();
-        assert(tychoRouter.swapExecutors(BOB) == false);
-    }
-
     function testRemoveExecutorMissingSetterRole() public {
         vm.expectRevert();
         tychoRouter.removeSwapExecutor(BOB);
@@ -57,15 +36,6 @@ contract TychoRouterTest is TychoRouterTestSetup {
         tychoRouter.setSwapExecutor(DUMMY);
     }
 
-    function testSetExecutorNonContract() public {
-        vm.startPrank(executorSetter);
-        vm.expectRevert(
-            abi.encodeWithSelector(TychoRouter__NonContractExecutor.selector)
-        );
-        tychoRouter.setSwapExecutor(BOB);
-        vm.stopPrank();
-    }
-
     function testSetValidVerifier() public {
         vm.startPrank(executorSetter);
         vm.expectEmit();

foundry/test/TychoRouterTestSetup.sol

@@ -28,14 +28,6 @@ contract TychoRouterTestSetup is Test, Constants {
         vm.stopPrank();
     }
 
-    /**
-     * @dev Deploys a dummy contract with non-empty bytecode
-     */
-    function deployDummyContract() internal {
-        bytes memory minimalBytecode = hex"01"; // Single-byte bytecode
-        vm.etch(DUMMY, minimalBytecode); // Deploy minimal bytecode
-    }
-
     /**
      * @dev Mints tokens to the given address
      * @param amount The amount of tokens to mint