Merge pull request #136 from 1inch/feature/priority-fee-limiter

add priority fee limiter
1inch · Nov 2, 2023 · ff7909c · ff7909c
2 parents c9429f3 + 7b5fa16
commit ff7909c
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diff --git a/contracts/SettlementExtension.sol b/contracts/SettlementExtension.sol
@@ -19,6 +19,7 @@ contract SettlementExtension is IPostInteraction, IAmountGetter, FeeBankCharger
 
     error OnlyLimitOrderProtocol();
     error ResolverIsNotWhitelisted();
+    error InvalidPriorityFee();
 
     uint256 private constant _TAKING_FEE_BASE = 1e9;
     uint256 private constant _ORDER_FEE_BASE_POINTS = 1e15;
@@ -119,7 +120,10 @@ contract SettlementExtension is IPostInteraction, IAmountGetter, FeeBankCharger
         bytes calldata extraData
     ) external onlyLimitOrderProtocol {
         (uint256 resolverFee, address integrator, uint256 integrationFee, bytes calldata whitelist) = _parseFeeData(extraData, order.makingAmount, makingAmount, takingAmount);
+
         if (!_isWhitelisted(whitelist, taker)) revert ResolverIsNotWhitelisted();
+        if (!_isPriorityFeeValid()) revert InvalidPriorityFee();
+
         _chargeFee(taker, resolverFee);
         if (integrationFee > 0) {
             IERC20(order.takerAsset.get()).safeTransferFrom(taker, integrator, integrationFee);
@@ -180,4 +184,24 @@ contract SettlementExtension is IPostInteraction, IAmountGetter, FeeBankCharger
             return false;
         }
     }
+
+    /// @notice Validates priority fee according to the spec
+    /// https://snapshot.org/#/1inch.eth/proposal/0xa040c60050147a0f67042ae024673e92e813b5d2c0f748abf70ddfa1ed107cbe
+    /// For blocks with baseFee <10.6 gwei – the priorityFee is capped at 70% of the baseFee.
+    /// For blocks with baseFee between 10.6 gwei and 104.1 gwei – the priorityFee is capped at 50% of the baseFee.
+    /// For blocks with baseFee >104.1 gwei – priorityFee is capped at 65% of the block’s baseFee.
+    function _isPriorityFeeValid() private view returns(bool) {
+        unchecked {
+            uint256 baseFee = block.basefee;
+            uint256 priorityFee = tx.gasprice - baseFee;
+
+            if (baseFee < 10.6 gwei) {
+                return priorityFee * 100 <= baseFee * 70;
+            } else if (baseFee < 104.1 gwei) {
+                return priorityFee * 2 <= baseFee;
+            } else {
+                return priorityFee * 100 <= baseFee * 65;
+            }
+        }
+    }
 }
diff --git a/hardhat.networks.js b/hardhat.networks.js
@@ -1,4 +1,9 @@
-const networks = {};
+const networks = {
+    hardhat: {
+        initialBaseFeePerGas: 1,
+        gasPrice: 1,
+    },
+};
 const etherscan = { apiKey: {}, customChains: [] };
 
 if (process.env.ZKSYNC_PRIVATE_KEY) {

diff --git a/test/PriorityFeeLimiter.js b/test/PriorityFeeLimiter.js
@@ -0,0 +1,98 @@
+const { expect, deployContract, time, ether, trim0x, constants } = require('@1inch/solidity-utils');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
+const { buildOrder, buildMakerTraits } = require('@1inch/limit-order-protocol-contract/test/helpers/orderUtils');
+const { initContractsForSettlement } = require('./helpers/fixtures');
+const hre = require('hardhat');
+const { ethers, network } = hre;
+
+describe('PriorityFeeLimiter', function () {
+    before(async function () {
+        if (hre.__SOLIDITY_COVERAGE_RUNNING) { this.skip(); }
+    });
+
+    after(async function () {
+        await network.provider.send('hardhat_setNextBlockBaseFeePerGas', ['0x1']);
+    });
+
+    async function prepare() {
+        const { contracts: { dai, weth }, accounts: { owner } } = await initContractsForSettlement();
+        const settlementExtension = await deployContract('SettlementExtension', [owner.address, weth.address]);
+        const currentTime = (await time.latest()) - time.duration.minutes(1);
+
+        const postInteractionData = ethers.utils.solidityPack(
+            ['uint8', 'uint32', 'bytes10', 'uint16'],
+            [0, currentTime, '0x' + owner.address.substring(22), 0],
+        );
+
+        const order = buildOrder({
+            maker: owner.address,
+            makerAsset: dai.address,
+            takerAsset: weth.address,
+            makingAmount: ether('10'),
+            takingAmount: ether('1'),
+            makerTraits: buildMakerTraits(),
+        }, {
+            postInteraction: settlementExtension.address + trim0x(postInteractionData),
+        });
+
+        return { order, owner, postInteractionData, settlementExtension };
+    }
+
+    function sendPostInteractionTxn(settlementExtension, order, owner, postInteractionData, maxPriorityFeePerGas) {
+        return settlementExtension.postInteraction(
+            order, '0x', constants.ZERO_BYTES32, owner.address, ether('10'), ether('1'), ether('10'), postInteractionData,
+            { maxPriorityFeePerGas },
+        );
+    }
+
+    it('8 gwei base, 4 gwei priority should work', async function () {
+        const { order, owner, postInteractionData, settlementExtension } = await loadFixture(prepare);
+
+        await network.provider.send('hardhat_setNextBlockBaseFeePerGas', ['0x1dcd65000']); // 8 gwei
+
+        await sendPostInteractionTxn(settlementExtension, order, owner, postInteractionData, 4000000000);
+    });
+
+    it('8 gwei base, 6 gwei priority should not work', async function () {
+        const { order, owner, postInteractionData, settlementExtension } = await loadFixture(prepare);
+
+        await network.provider.send('hardhat_setNextBlockBaseFeePerGas', ['0x1dcd65000']); // 8 gwei
+
+        const postInteractionTxn = sendPostInteractionTxn(settlementExtension, order, owner, postInteractionData, 6000000000);
+        await expect(postInteractionTxn).to.be.revertedWithCustomError(settlementExtension, 'InvalidPriorityFee');
+    });
+
+    it('50 gwei base, 25 gwei priority should work', async function () {
+        const { order, owner, postInteractionData, settlementExtension } = await loadFixture(prepare);
+
+        await network.provider.send('hardhat_setNextBlockBaseFeePerGas', ['0xba43b7400']); // 50 gwei
+
+        await sendPostInteractionTxn(settlementExtension, order, owner, postInteractionData, 25000000000);
+    });
+
+    it('50 gwei base, 26 gwei priority should not work', async function () {
+        const { order, owner, postInteractionData, settlementExtension } = await loadFixture(prepare);
+
+        await network.provider.send('hardhat_setNextBlockBaseFeePerGas', ['0xba43b7400']); // 50 gwei
+
+        const postInteractionTxn = sendPostInteractionTxn(settlementExtension, order, owner, postInteractionData, 26000000000);
+        await expect(postInteractionTxn).to.be.revertedWithCustomError(settlementExtension, 'InvalidPriorityFee');
+    });
+
+    it('150 gwei base, 90 gwei priority should work', async function () {
+        const { order, owner, postInteractionData, settlementExtension } = await loadFixture(prepare);
+
+        await network.provider.send('hardhat_setNextBlockBaseFeePerGas', ['0x22ecb25c00']); // 150 gwei
+
+        await sendPostInteractionTxn(settlementExtension, order, owner, postInteractionData, 90000000000);
+    });
+
+    it('150 gwei base, 100 gwei priority should not work', async function () {
+        const { order, owner, postInteractionData, settlementExtension } = await loadFixture(prepare);
+
+        await network.provider.send('hardhat_setNextBlockBaseFeePerGas', ['0x22ecb25c00']); // 150 gwei
+
+        const postInteractionTxn = sendPostInteractionTxn(settlementExtension, order, owner, postInteractionData, 100000000000);
+        await expect(postInteractionTxn).to.be.revertedWithCustomError(settlementExtension, 'InvalidPriorityFee');
+    });
+});