improve

Snowfork · Apr 14, 2024 · 3985ce5 · 3985ce5
1 parent dd4ca4b
commit 3985ce5
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Showing 3 changed files with 21 additions and 21 deletions.
diff --git a/contracts/src/Assets.sol b/contracts/src/Assets.sol
@@ -42,7 +42,7 @@ library Assets {
         IERC20(token).safeTransferFrom(sender, agent, amount);
     }
 
-    function sendTokenCosts(address token, ParaID destinationChain, uint128 destinationChainFee)
+    function sendTokenCosts(address token, ParaID destinationChain, uint128 destinationChainFee, uint128 maxDestinationChainFee)
         external
         view
         returns (Costs memory costs)
@@ -53,10 +53,10 @@ library Assets {
             revert TokenNotRegistered();
         }
 
-        return _sendTokenCosts(destinationChain, destinationChainFee);
+        return _sendTokenCosts(destinationChain, destinationChainFee, maxDestinationChainFee);
     }
 
-    function _sendTokenCosts(ParaID destinationChain, uint128 destinationChainFee)
+    function _sendTokenCosts(ParaID destinationChain, uint128 destinationChainFee, uint128 maxDestinationChainFee)
         internal
         view
         returns (Costs memory costs)
@@ -65,6 +65,19 @@ library Assets {
         if ($.assetHubParaID == destinationChain) {
             costs.foreign = $.assetHubReserveTransferFee;
         } else {
+            // Reduce the ability for users to perform arbitrage by exploiting a
+            // favourable exchange rate. For example supplying Ether
+            // and gaining a more valuable amount of DOT on the destination chain.
+            //
+            // Also prevents users from mistakenly sending more fees than would be required
+            // which has negative effects like draining AssetHub's sovereign account.
+            //
+            // For safety, `maxDestinationChainFee` should be less valuable
+            // than the gas cost to send tokens.
+            if (destinationChainFee > maxDestinationChainFee) {
+                revert InvalidDestinationFee();
+            }
+
             // If the final destination chain is not AssetHub, then the fee needs to additionally
             // include the cost of executing an XCM on the final destination parachain.
             costs.foreign = $.assetHubReserveTransferFee + destinationChainFee;
@@ -89,24 +102,11 @@ library Assets {
             revert TokenNotRegistered();
         }
 
-        // Reduce the ability for users to perform arbitrage by exploiting a
-        // favourable exchange rate. For example supplying Ether
-        // and gaining a more valuable amount of DOT on the destination chain.
-        //
-        // Also prevents users from mistakenly sending more fees than would be required
-        // which has negative effects like draining AssetHub's sovereign account.
-        //
-        // For safety, `maxDestinationChainFee` should be less valuable
-        // than the gas cost to send tokens.
-        if (destinationChainFee > maxDestinationChainFee) {
-            revert InvalidDestinationFee();
-        }
-
         // Lock the funds into AssetHub's agent contract
         _transferToAgent($.assetHubAgent, token, sender, amount);
 
         ticket.dest = $.assetHubParaID;
-        ticket.costs = _sendTokenCosts(destinationChain, destinationChainFee);
+        ticket.costs = _sendTokenCosts(destinationChain, destinationChainFee, maxDestinationChainFee);
 
         // Construct a message payload
         if (destinationChain == $.assetHubParaID) {

diff --git a/contracts/src/Gateway.sol b/contracts/src/Gateway.sol
@@ -404,7 +404,7 @@ contract Gateway is IGateway, IInitializable, IUpgradable {
         view
         returns (uint256)
     {
-        return _calculateFee(Assets.sendTokenCosts(token, destinationChain, destinationFee));
+        return _calculateFee(Assets.sendTokenCosts(token, destinationChain, destinationFee, MAX_DESTINATION_FEE));
     }
 
     // Transfer ERC20 tokens to a Polkadot parachain

diff --git a/contracts/test/Gateway.t.sol b/contracts/test/Gateway.t.sol
@@ -853,10 +853,10 @@ contract GatewayTest is Test {
         uint256 fee = IGateway(address(gateway)).quoteRegisterTokenFee();
         IGateway(address(gateway)).registerToken{value: fee}(address(token));
 
-        uint128 largeFee = maxDestinationFee + 1; // greater than 10 DOT, 10 decimal places
-        fee = IGateway(address(gateway)).quoteSendTokenFee(address(token), destPara, largeFee);
+        vm.expectRevert(Assets.InvalidDestinationFee.selector);
+        IGateway(address(gateway)).quoteSendTokenFee(address(token), destPara, maxDestinationFee + 1);
 
         vm.expectRevert(Assets.InvalidDestinationFee.selector);
-        IGateway(address(gateway)).sendToken{value: fee}(address(token), destPara, recipientAddress32, largeFee, 1);
+        IGateway(address(gateway)).sendToken{value: fee}(address(token), destPara, recipientAddress32, maxDestinationFee + 1, 1);
     }
 }