impl

Signed-off-by: Ihor Farion <ihor@umaproject.org>

Author: grasphoper

contracts/periphery/mintburn/sponsored-oft/ComposeMsgCodec.sol

@@ -5,19 +5,21 @@ import { BytesLib } from "../../../external/libraries/BytesLib.sol";
 /// @notice Codec for params passed in OFT `composeMsg`.
 library ComposeMsgCodec {
     uint256 internal constant NONCE_OFFSET = 0;
-    uint256 internal constant DEADLINE_OFFSET = 32;
-    uint256 internal constant MAX_BPS_TO_SPONSOR_OFFSET = 64;
-    uint256 internal constant MAX_USER_SLIPPAGE_BPS_OFFSET = 96;
-    uint256 internal constant FINAL_RECIPIENT_OFFSET = 128;
-    uint256 internal constant FINAL_TOKEN_OFFSET = 160;
-    uint256 internal constant DESTINATION_DEX_OFFSET = 192;
-    uint256 internal constant ACCOUNT_CREATION_MODE_OFFSET = 224;
-    uint256 internal constant EXECUTION_MODE_OFFSET = 256;
-    // Minimum length with empty actionData: 9 regular params (32 bytes each) and 1 dynamic byte array (minumum 64 bytes)
-    uint256 internal constant MIN_COMPOSE_MSG_BYTE_LENGTH = 352;
+    uint256 internal constant AMOUNT_LD_OFFSET = 32;
+    uint256 internal constant DEADLINE_OFFSET = 64;
+    uint256 internal constant MAX_BPS_TO_SPONSOR_OFFSET = 96;
+    uint256 internal constant MAX_USER_SLIPPAGE_BPS_OFFSET = 128;
+    uint256 internal constant FINAL_RECIPIENT_OFFSET = 160;
+    uint256 internal constant FINAL_TOKEN_OFFSET = 192;
+    uint256 internal constant DESTINATION_DEX_OFFSET = 224;
+    uint256 internal constant ACCOUNT_CREATION_MODE_OFFSET = 256;
+    uint256 internal constant EXECUTION_MODE_OFFSET = 288;
+    // Minimum length with empty actionData: 10 regular params (32 bytes each) and 1 dynamic byte array (minumum 64 bytes)
+    uint256 internal constant MIN_COMPOSE_MSG_BYTE_LENGTH = 384;
 
     function _encode(
         bytes32 nonce,
+        uint256 amountLD,
         uint256 deadline,
         uint256 maxBpsToSponsor,
         uint256 maxUserSlippageBps,
@@ -31,6 +33,7 @@ library ComposeMsgCodec {
         return
             abi.encode(
                 nonce,
+                amountLD,
                 deadline,
                 maxBpsToSponsor,
                 maxUserSlippageBps,
@@ -47,6 +50,10 @@ library ComposeMsgCodec {
         return BytesLib.toBytes32(data, NONCE_OFFSET);
     }
 
+    function _getAmountLD(bytes memory data) internal pure returns (uint256 v) {
+        return BytesLib.toUint256(data, AMOUNT_LD_OFFSET);
+    }
+
     function _getDeadline(bytes memory data) internal pure returns (uint256 v) {
         return BytesLib.toUint256(data, DEADLINE_OFFSET);
     }
@@ -83,9 +90,9 @@ library ComposeMsgCodec {
     }
 
     function _getActionData(bytes memory data) internal pure returns (bytes memory v) {
-        (, , , , , , , , , bytes memory actionData) = abi.decode(
+        (, , , , , , , , , , bytes memory actionData) = abi.decode(
             data,
-            (bytes32, uint256, uint256, uint256, bytes32, bytes32, uint32, uint8, uint8, bytes)
+            (bytes32, uint256, uint256, uint256, uint256, bytes32, bytes32, uint32, uint8, uint8, bytes)
         );
         return actionData;
     }

contracts/periphery/mintburn/sponsored-oft/DstOFTHandler.sol

@@ -27,10 +27,6 @@ contract DstOFTHandler is BaseModuleHandler, ILayerZeroComposer, ArbitraryEVMFlo
     using AddressToBytes32 for address;
     using SafeERC20 for IERC20;
 
-    /// @notice We expect bridge amount that comes through to this Handler to be 1:1 with the src send amount, and we
-    /// require our src handler to ensure that it is. We don't sponsor extra bridge fees in this handler
-    uint256 public constant EXTRA_FEES_TO_SPONSOR = 0;
-
     address public immutable OFT_ENDPOINT_ADDRESS;
     address public immutable IOFT_ADDRESS;
 
@@ -162,6 +158,15 @@ contract DstOFTHandler is BaseModuleHandler, ILayerZeroComposer, ArbitraryEVMFlo
         $.usedNonces[quoteNonce] = true;
 
         uint256 amountLD = OFTComposeMsgCodec.amountLD(_message);
+        // We trust the src keyword to record the real send amount.
+        // This is safe because the source contract validates the signature of the quote.
+        uint256 amountSentLD = composeMsg._getAmountLD();
+
+        uint256 extraFeesIncurred = 0;
+        if (amountSentLD > amountLD) {
+            extraFeesIncurred = amountSentLD - amountLD;
+        }
+
         uint256 maxBpsToSponsor = composeMsg._getMaxBpsToSponsor();
         uint256 maxUserSlippageBps = composeMsg._getMaxUserSlippageBps();
         address finalRecipient = composeMsg._getFinalRecipient().toAddress();
@@ -178,7 +183,7 @@ contract DstOFTHandler is BaseModuleHandler, ILayerZeroComposer, ArbitraryEVMFlo
             finalToken: finalToken,
             destinationDex: destinationDex,
             maxBpsToSponsor: maxBpsToSponsor,
-            extraFeesIncurred: EXTRA_FEES_TO_SPONSOR,
+            extraFeesIncurred: extraFeesIncurred,
             accountCreationMode: AccountCreationMode(accountCreationMode)
         });
 

contracts/periphery/mintburn/sponsored-oft/QuoteSignLib.sol

@@ -31,6 +31,7 @@ library QuoteSignLib {
                 p.destinationDex,
                 p.lzReceiveGasLimit,
                 p.lzComposeGasLimit,
+                p.maxOftFeeBps,
                 p.accountCreationMode,
                 p.executionMode,
                 keccak256(p.actionData) // Hash the actionData to keep signature size reasonable

contracts/periphery/mintburn/sponsored-oft/SponsoredOFTSrcPeriphery.sol

@@ -30,6 +30,8 @@ contract SponsoredOFTSrcPeriphery is Ownable {
     /// @notice Source endpoint id
     uint32 public immutable SRC_EID;
 
+    mapping(uint32 dstEid => int8 decimalDiff) public dstEidToDecimalsDiff;
+
     /// @custom:storage-location erc7201:SponsoredOFTSrcPeriphery.main
     struct MainStorage {
         /// @notice Signer public key to check the signed quote against
@@ -83,6 +85,8 @@ contract SponsoredOFTSrcPeriphery is Ownable {
     error NonceAlreadyUsed();
     /// @notice Thrown when provided msg.value is not sufficient to cover OFT bridging fee
     error InsufficientNativeFee();
+    /// @notice Thrown when array lengths do not match
+    error ArrayLengthMismatch();
 
     constructor(address _token, address _oftMessenger, uint32 _srcEid, address _signer) {
         TOKEN = _token;
@@ -161,8 +165,14 @@ contract SponsoredOFTSrcPeriphery is Ownable {
     function _buildOftTransfer(
         Quote calldata quote
     ) internal view returns (SendParam memory, MessagingFee memory, address) {
+        uint256 amountDstLD = _applyDecimalDiff(
+            quote.signedParams.amountLD,
+            dstEidToDecimalsDiff[quote.signedParams.dstEid]
+        );
+
         bytes memory composeMsg = ComposeMsgCodec._encode(
             quote.signedParams.nonce,
+            amountDstLD,
             quote.signedParams.deadline,
             quote.signedParams.maxBpsToSponsor,
             quote.unsignedParams.maxUserSlippageBps,
@@ -179,12 +189,14 @@ contract SponsoredOFTSrcPeriphery is Ownable {
             .addExecutorLzReceiveOption(uint128(quote.signedParams.lzReceiveGasLimit), uint128(0))
             .addExecutorLzComposeOption(uint16(0), uint128(quote.signedParams.lzComposeGasLimit), uint128(0));
 
+        // Use maxOftFeeBps to calculate minAmountLD based on expected destination amount
+        uint256 minAmountLD = (amountDstLD * (10000 - quote.signedParams.maxOftFeeBps)) / 10000;
+
         SendParam memory sendParam = SendParam(
             quote.signedParams.dstEid,
             quote.signedParams.destinationHandler,
-            // Only support OFT sends that don't take fees in sent token. Set `minAmountLD = amountLD` to enforce this
-            quote.signedParams.amountLD,
             quote.signedParams.amountLD,
+            minAmountLD,
             extraOptions,
             composeMsg,
             // Only support empty OFT commands
@@ -196,6 +208,21 @@ contract SponsoredOFTSrcPeriphery is Ownable {
         return (sendParam, fee, quote.unsignedParams.refundRecipient);
     }
 
+    /**
+     * @notice Applies decimal difference to the amount
+     * @param amount The amount to adjust
+     * @param diff The decimal difference (positive: multiply, negative: divide)
+     * @return The adjusted amount
+     */
+    function _applyDecimalDiff(uint256 amount, int8 diff) internal pure returns (uint256) {
+        if (diff > 0) {
+            return amount * (10 ** uint8(diff));
+        } else if (diff < 0) {
+            return amount / (10 ** uint8(-diff));
+        }
+        return amount;
+    }
+
     function _validateQuote(Quote calldata quote, bytes calldata signature) internal view {
         MainStorage storage $ = _getMainStorage();
         if (!QuoteSignLib.isSignatureValid($.signer, quote.signedParams, signature)) {
@@ -215,4 +242,18 @@ contract SponsoredOFTSrcPeriphery is Ownable {
     function setSigner(address _newSigner) external onlyOwner {
         _getMainStorage().signer = _newSigner;
     }
+
+    /**
+     * @notice Sets the decimal difference for destination chains
+     * @param dstEids Array of destination endpoint IDs
+     * @param decimalDiffs Array of decimal differences (positive for Src < Dst, negative for Src > Dst)
+     */
+    function setDstEidToDecimalsDiff(uint32[] calldata dstEids, int8[] calldata decimalDiffs) external onlyOwner {
+        if (dstEids.length != decimalDiffs.length) {
+            revert ArrayLengthMismatch();
+        }
+        for (uint256 i = 0; i < dstEids.length; ++i) {
+            dstEidToDecimalsDiff[dstEids[i]] = decimalDiffs[i];
+        }
+    }
 }

contracts/periphery/mintburn/sponsored-oft/Structs.sol

@@ -35,6 +35,7 @@ struct SignedQuoteParams {
     uint256 lzReceiveGasLimit; // gas limit for `lzReceive` call on destination side
     uint256 lzComposeGasLimit; // gas limit for `lzCompose` call on destination side
     // Execution mode and action data
+    uint256 maxOftFeeBps; // max fee deducted by the OFT bridge
     uint8 accountCreationMode; // AccountCreationMode: Standard or FromUserFunds
     uint8 executionMode; // ExecutionMode: DirectToCore, ArbitraryActionsToCore, or ArbitraryActionsToEVM
     bytes actionData; // Encoded action data for arbitrary execution. Empty for DirectToCore mode.