Handling ssc cost via stakes.

Author: mijovic

contracts/core/EntryPoint.sol

@@ -7,6 +7,7 @@ import "../interfaces/IAccount.sol";
 import "../interfaces/IAccountExecute.sol";
 import "../interfaces/IPaymaster.sol";
 import "../interfaces/IEntryPoint.sol";
+import "../interfaces/ISscOpcodes.sol";
 
 import "../utils/Exec.sol";
 import "./StakeManager.sol";
@@ -28,8 +29,20 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
 
     using UserOperationLib for PackedUserOperation;
 
+    int256 constant public SSC_STORAGE_SLOT_COST = 12800000000000000;
+    int256 constant public SSC_STORAGE_SLOT_REFUND = 12672000000000000;
+
+    int256 constant public SSC_ACCOUNT_COST = 12800000000000000;
+    int256 constant public SSC_ACCOUNT_REFUND = 12672000000000000;
+
+    int256 constant public SSC_CODE_CREATED_COST = 12800000000000000;
+
+    uint256 constant public SSC_MAX_SPEND_FACTOR = 10;
+
     SenderCreator private immutable _senderCreator = new SenderCreator();
 
+    ISscOpcodes private immutable _ssc = ISscOpcodes(address(0x665e930982A9a03c844641d453a2C3462ED7Ff41));
+
     function senderCreator() internal view virtual returns (SenderCreator) {
         return _senderCreator;
     }
@@ -174,10 +187,12 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
     function handleOps(
         PackedUserOperation[] calldata ops,
         address payable beneficiary
-    ) public nonReentrant {
+    ) public nonReentrant payable {
         uint256 opslen = ops.length;
         UserOpInfo[] memory opInfos = new UserOpInfo[](opslen);
 
+        int256 preSSC = _netSSC();
+
         unchecked {
             for (uint256 i = 0; i < opslen; i++) {
                 UserOpInfo memory opInfo = opInfos[i];
@@ -200,7 +215,12 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
                 collected += _executeUserOp(i, ops[i], opInfos[i]);
             }
 
-            _compensate(beneficiary, collected);
+            // this can be negative in cases of refunds
+            int256 netSSC = _netSSC() - preSSC;
+            // In case of negative netSSC msg.value must be higher than abs(netSSC)
+            uint256 sscCompensation = uint256(int256(msg.value) + netSSC);
+
+            _compensate(beneficiary, collected + sscCompensation);
         }
     }
 
@@ -303,23 +323,10 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
         uint256 preOpGas;
     }
 
-    /**
-     * Inner function to handle a UserOperation.
-     * Must be declared "external" to open a call context, but it can only be called by handleOps.
-     * @param callData - The callData to execute.
-     * @param opInfo   - The UserOpInfo struct.
-     * @param context  - The context bytes.
-     * @return actualGasCost - the actual cost in eth this UserOperation paid for gas
-     */
-    function innerHandleOp(
-        bytes memory callData,
-        UserOpInfo memory opInfo,
-        bytes calldata context
-    ) external returns (uint256 actualGasCost) {
-        uint256 preGas = gasleft();
+    function innerExecuteCall(MemoryUserOp memory mUserOp, bytes memory callData) external {
         require(msg.sender == address(this), "AA92 internal call only");
-        MemoryUserOp memory mUserOp = opInfo.mUserOp;
 
+        int256 preSSC = _netSSC();
         uint256 callGasLimit = mUserOp.callGasLimit;
         unchecked {
             // handleOps was called with gas limit too low. abort entire bundle.
@@ -335,12 +342,46 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
                 }
             }
         }
+        if (callData.length > 0) {
+            bool success = Exec.call(mUserOp.sender, 0, callData, callGasLimit);
+            if (!success) {
+                require(false, string(Exec.getReturnData(REVERT_REASON_MAX_LEN)));
+            } else {
+                int256 netSSC = _netSSC() - preSSC;
+                if (netSSC < 0) {
+                    // increment deposit for the user's account
+                    _incrementDeposit(mUserOp.sender, uint256(-netSSC));
+                } else {
+                    require(uint256(netSSC) <= SSC_MAX_SPEND_FACTOR * callGasLimit * getUserOpGasPrice(mUserOp), "AA97 ssc max cost violation");
+                    _decrementDeposit(mUserOp.sender, uint256(netSSC));
+                }
+            }
+        }
+    }
+
+    /**
+     * Inner function to handle a UserOperation.
+     * Must be declared "external" to open a call context, but it can only be called by handleOps.
+     * @param callData - The callData to execute.
+     * @param opInfo   - The UserOpInfo struct.
+     * @param context  - The context bytes.
+     * @return actualGasCost - the actual cost in eth this UserOperation paid for gas
+     */
+    function innerHandleOp(
+        bytes memory callData,
+        UserOpInfo memory opInfo,
+        bytes calldata context
+    ) external returns (uint256 actualGasCost) {
+        uint256 preGas = gasleft();
+        require(msg.sender == address(this), "AA92 internal call only");
+        MemoryUserOp memory mUserOp = opInfo.mUserOp;
 
         IPaymaster.PostOpMode mode = IPaymaster.PostOpMode.opSucceeded;
         if (callData.length > 0) {
-            bool success = Exec.call(mUserOp.sender, 0, callData, callGasLimit);
+            (bool success, bytes memory result) = address(this).call(
+                abi.encodeWithSelector(this.innerExecuteCall.selector, mUserOp, callData)
+            );
             if (!success) {
-                bytes memory result = Exec.getReturnData(REVERT_REASON_MAX_LEN);
                 if (result.length > 0) {
                     emit UserOperationRevertReason(
                         opInfo.userOpHash,
@@ -413,6 +454,15 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
         }
     }
 
+    /**
+     * Calculates total ssc cost / refund
+     */
+    function _netSSC() internal view returns (int256) {
+        return int256(_ssc.accountsCreated()) * SSC_ACCOUNT_COST - int256(_ssc.accountsCleared()) * SSC_ACCOUNT_REFUND
+            + int256(_ssc.slotsCreated()) * SSC_STORAGE_SLOT_COST - int256(_ssc.slotsCleared()) * SSC_STORAGE_SLOT_REFUND
+            + int256(_ssc.codeCreated()) * SSC_CODE_CREATED_COST;
+    }
+
     /**
      * Create sender smart contract account if init code is provided.
      * @param opIndex  - The operation index.

contracts/core/StakeManager.sol

@@ -56,6 +56,22 @@ abstract contract StakeManager is IStakeManager {
         return newAmount;
     }
 
+    /**
+     * Increments an account's deposit.
+     * @param account - The account to increment.
+     * @param amount  - The amount to increment by.
+     * @return the updated deposit of this account
+     */
+    function _decrementDeposit(address account, uint256 amount) internal returns (uint256) {
+        unchecked {
+            DepositInfo storage info = deposits[account];
+            require(info.deposit >= amount, "cannot decrement stake");
+            uint256 newAmount = info.deposit - amount;
+            info.deposit = newAmount;
+            return newAmount;
+        }
+    }
+
     /**
      * Add to the deposit of the given account.
      * @param account - The account to add to.

contracts/interfaces/IEntryPoint.sol

@@ -154,7 +154,7 @@ interface IEntryPoint is IStakeManager, INonceManager {
     function handleOps(
         PackedUserOperation[] calldata ops,
         address payable beneficiary
-    ) external;
+    ) external payable;
 
     /**
      * Execute a batch of UserOperation with Aggregators

contracts/interfaces/ISscOpcodes.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity ^0.8.23;
+
+interface ISscOpcodes {
+    function accountsCreated() external view returns (uint256); // D0
+    function accountsCleared() external view returns (uint256); // D1
+    function slotsCreated() external view returns (uint256); // D2
+    function slotsCleared() external view returns (uint256); // D3
+    function codeCreated() external view returns (uint256); // D4
+}