feat: add fee handler for substrate

contracts/handlers/fee/FeeHandlerGeneric.sol

@@ -0,0 +1,92 @@
+// The Licensed Work is (c) 2022 Sygma
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity 0.8.11;
+
+import "./FeeHandlerWithOracle.sol";
+
+/**
+    @title Handles deposit fees for generic messages based on Effective rates provided by Fee oracle.
+    @author ChainSafe Systems.
+    @notice This contract is intended to be used with the Bridge contract.
+ */
+contract FeeHandlerGeneric is FeeHandlerWithOracle {
+
+    /**
+        @param bridgeAddress Contract address of previously deployed Bridge.
+        @param feeHandlerRouterAddress Contract address of previously deployed FeeHandlerRouter.
+     */
+    constructor(address bridgeAddress, address feeHandlerRouterAddress) FeeHandlerWithOracle(bridgeAddress, feeHandlerRouterAddress) {
+    }
+
+     /**
+        @notice Calculates fee for generic messages.
+        This function is almost identical to the _calculateFee function in the base contract.
+        The difference is the txCost calculation formula.
+        @param sender Sender of the deposit.
+        @param fromDomainID ID of the source chain.
+        @param destinationDomainID ID of chain deposit will be bridged to.
+        @param resourceID ResourceID to be used when making deposits.
+        @param depositData Additional data to be passed to specified handler.
+        @param feeData Additional data to be passed to the fee handler.
+        @return fee Returns the fee amount.
+        @return tokenAddress Returns the address of the token to be used for fee.
+     */
+    function _calculateFee(address sender, uint8 fromDomainID, uint8 destinationDomainID, bytes32 resourceID, bytes calldata depositData, bytes calldata feeData) internal view override returns(uint256 fee, address tokenAddress) {
+         /**
+            Message:
+            ber * 10^18:  uint256
+            ter * 10^18:  uint256 (not used)
+            dstGasPrice:  uint256
+            expiresAt:    uint256
+            fromDomainID: uint8 encoded as uint256
+            toDomainID:   uint8 encoded as uint256
+            resourceID:   bytes32
+            msgGasLimit:  uint256
+            sig:          bytes(65 bytes)
+
+            total in bytes:
+            message:
+            32 * 8  = 256
+            message + sig:
+            256 + 65 = 321
+
+            amount: uint256
+            total: 353
+        */
+
+        require(feeData.length == 353, "Incorrect feeData length");
+
+        FeeDataType memory feeDataDecoded;
+        uint256 txCost;
+
+        feeDataDecoded.message = bytes(feeData[: 256]);
+        feeDataDecoded.sig = bytes(feeData[256: 321]);
+        feeDataDecoded.amount = abi.decode(feeData[321:], (uint256));
+
+        OracleMessageType memory oracleMessage = abi.decode(feeDataDecoded.message, (OracleMessageType));
+        require(block.timestamp <= oracleMessage.expiresAt, "Obsolete oracle data");
+        require((oracleMessage.fromDomainID == fromDomainID)
+            && (oracleMessage.toDomainID == destinationDomainID)
+            && (oracleMessage.resourceID == resourceID),
+            "Incorrect deposit params"
+        );
+
+        bytes32 messageHash = keccak256(feeDataDecoded.message);
+
+        verifySig(messageHash, feeDataDecoded.sig, _oracleAddress);
+
+        address tokenHandler = IBridge(_bridgeAddress)._resourceIDToHandlerAddress(resourceID);
+        address tokenAddress = IERCHandler(tokenHandler)._resourceIDToTokenContractAddress(resourceID);
+
+        require(oracleMessage.msgGasLimit > 0, "msgGasLimit == 0");
+        // txCost = dstGasPrice * oracleMessage.msgGasLimit * Base Effective Rate (rate between base currencies of source and dest)
+        txCost = oracleMessage.dstGasPrice * oracleMessage.msgGasLimit * oracleMessage.ber / 1e18;
+
+        fee = feeDataDecoded.amount * _feePercent / 1e4; // 100 for percent and 100 to avoid precision loss
+
+        if (fee < txCost) {
+            fee = txCost;
+        }
+        return (fee, tokenAddress);
+    }
+}

contracts/handlers/fee/FeeHandlerSubstrate.sol

@@ -0,0 +1,107 @@
+// The Licensed Work is (c) 2022 Sygma
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity 0.8.11;
+
+import "./FeeHandlerWithOracle.sol";
+
+/**
+    @title Handles deposit fees on Substrate based on Effective rates provided by Fee oracle.
+    @author ChainSafe Systems.
+    @notice This contract is intended to be used with the Bridge contract.
+ */
+contract FeeHandlerSubstrate is FeeHandlerWithOracle {
+
+    struct SubstrateOracleMessageType {
+        // Base Effective Rate - effective rate between base currencies of source and dest networks (eg. MATIC/ETH)
+        uint256 ber;
+        // Token Effective Rate - rate between base currency of destination network and token that is being trasferred (eg. MATIC/USDT)
+        uint256 ter;
+        // Final fee - resulting fee calculated by the oracle
+        uint256 finalFee;
+        uint256 expiresAt;
+        uint8 fromDomainID;
+        uint8 toDomainID;
+        bytes32 resourceID;
+        uint256 msgGasLimit;
+    }
+
+    /**
+        @param bridgeAddress Contract address of previously deployed Bridge.
+        @param feeHandlerRouterAddress Contract address of previously deployed FeeHandlerRouter.
+     */
+    constructor(address bridgeAddress, address feeHandlerRouterAddress) FeeHandlerWithOracle(bridgeAddress, feeHandlerRouterAddress) {
+    }
+
+     /**
+        @notice Calculates fee for deposit for Substrate.
+        This function is almost identical to the _calculateFee function in the base contract.
+        The differences are: unpacking of the oracle message and the txCost calculation formula.
+        Oracle will do the calculation of the tx cost and provide the resulting fee to the contract.
+        The resulting calculation is:
+        txCost = finalFee * oracleMessage.ter / 1e18
+        @param sender Sender of the deposit.
+        @param fromDomainID ID of the source chain.
+        @param destinationDomainID ID of chain deposit will be bridged to.
+        @param resourceID ResourceID to be used when making deposits.
+        @param depositData Additional data to be passed to specified handler.
+        @param feeData Additional data to be passed to the fee handler.
+        @return fee Returns the fee amount.
+        @return tokenAddress Returns the address of the token to be used for fee.
+     */
+    function _calculateFee(address sender, uint8 fromDomainID, uint8 destinationDomainID, bytes32 resourceID, bytes calldata depositData, bytes calldata feeData) internal view override returns(uint256 fee, address tokenAddress) {
+         /**
+            Message:
+            ber * 10^18:  uint256 (not used)
+            ter * 10^18:  uint256
+            finalFee:     uint256
+            expiresAt:    uint256
+            fromDomainID: uint8 encoded as uint256
+            toDomainID:   uint8 encoded as uint256
+            resourceID:   bytes32
+            msgGasLimit:  uint256 (not used)
+            sig:          bytes(65 bytes)
+
+            total in bytes:
+            message:
+            32 * 8  = 256
+            message + sig:
+            256 + 65 = 321
+
+            amount: uint256
+            total: 353
+        */
+
+        require(feeData.length == 353, "Incorrect feeData length");
+
+        FeeDataType memory feeDataDecoded;
+        uint256 txCost;
+
+        feeDataDecoded.message = bytes(feeData[: 256]);
+        feeDataDecoded.sig = bytes(feeData[256: 321]);
+        feeDataDecoded.amount = abi.decode(feeData[321:], (uint256));
+
+        SubstrateOracleMessageType memory oracleMessage = abi.decode(feeDataDecoded.message, (SubstrateOracleMessageType));
+        require(block.timestamp <= oracleMessage.expiresAt, "Obsolete oracle data");
+        require((oracleMessage.fromDomainID == fromDomainID)
+            && (oracleMessage.toDomainID == destinationDomainID)
+            && (oracleMessage.resourceID == resourceID),
+            "Incorrect deposit params"
+        );
+
+        bytes32 messageHash = keccak256(feeDataDecoded.message);
+
+        verifySig(messageHash, feeDataDecoded.sig, _oracleAddress);
+
+        address tokenHandler = IBridge(_bridgeAddress)._resourceIDToHandlerAddress(resourceID);
+        address tokenAddress = IERCHandler(tokenHandler)._resourceIDToTokenContractAddress(resourceID);
+
+        txCost = oracleMessage.finalFee * oracleMessage.ter / 1e18;
+
+        fee = feeDataDecoded.amount * _feePercent / 1e4; // 100 for percent and 100 to avoid precision loss
+
+        if (fee < txCost) {
+            fee = txCost;
+        }
+        return (fee, tokenAddress);
+    }
+}

contracts/handlers/fee/FeeHandlerWithOracle.sol

@@ -133,17 +133,17 @@ contract FeeHandlerWithOracle is IFeeHandler, AccessControl, ERC20Safe {
         return _calculateFee(sender, fromDomainID, destinationDomainID, resourceID, depositData, feeData);
     }
 
-    function _calculateFee(address sender, uint8 fromDomainID, uint8 destinationDomainID, bytes32 resourceID, bytes calldata depositData, bytes calldata feeData) internal view returns(uint256 fee, address tokenAddress) {
+    function _calculateFee(address sender, uint8 fromDomainID, uint8 destinationDomainID, bytes32 resourceID, bytes calldata depositData, bytes calldata feeData) internal view virtual returns(uint256 fee, address tokenAddress) {
         /**
             Message:
-            ber * 10^18:  uint256
+            ber * 10^18:  uint256 (not used)
             ter * 10^18:  uint256
             dstGasPrice:  uint256
             expiresAt:    uint256
             fromDomainID: uint8 encoded as uint256
             toDomainID:   uint8 encoded as uint256
             resourceID:   bytes32
-            msgGasLimit:  uint256
+            msgGasLimit:  uint256 (not used)
             sig:          bytes(65 bytes)
 
             total in bytes:
@@ -180,13 +180,8 @@ contract FeeHandlerWithOracle is IFeeHandler, AccessControl, ERC20Safe {
         address tokenHandler = IBridge(_bridgeAddress)._resourceIDToHandlerAddress(resourceID);
         address tokenAddress = IERCHandler(tokenHandler)._resourceIDToTokenContractAddress(resourceID);
 
-        if(oracleMessage.msgGasLimit > 0) {
-            // txCost = dstGasPrice * oracleMessage.msgGasLimit * Base Effective Rate (rate between base currencies of source and dest)
-            txCost = oracleMessage.dstGasPrice * oracleMessage.msgGasLimit * oracleMessage.ber / 1e18;
-        } else {
-            // txCost = dstGasPrice * _gasUsed * Token Effective Rate (rate of dest base currency to token)
-            txCost = oracleMessage.dstGasPrice * _gasUsed * oracleMessage.ter / 1e18;
-        }
+        // txCost = dstGasPrice * _gasUsed * Token Effective Rate (rate of dest base currency to token)
+        txCost = oracleMessage.dstGasPrice * _gasUsed * oracleMessage.ter / 1e18;
 
         fee = feeDataDecoded.amount * _feePercent / 1e4; // 100 for percent and 100 to avoid precision loss