// SPDX-License-Identifier: MIT OR Apache-2.0 pragma solidity >=0.8.0; /*@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@@@@@@@@@@@@@@@@@ @@@@@ HYPERLANE @@@@@@@ @@@@@@@@@@@@@@@@@@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@@ @@@@@@@@*/ // ============ Internal Imports ============ import {Message} from "../libs/Message.sol"; import {IGPMetadata} from "../libs/hooks/IGPMetadata.sol"; import {IGasOracle} from "../interfaces/IGasOracle.sol"; import {IInterchainGasPaymaster} from "../interfaces/IInterchainGasPaymaster.sol"; import {IPostDispatchHook} from "../interfaces/hooks/IPostDispatchHook.sol"; // ============ External Imports ============ import {Strings} from "@openzeppelin/contracts/utils/Strings.sol"; import {Address} from "@openzeppelin/contracts/utils/Address.sol"; import {OwnableUpgradeable} from "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol"; /** * @title InterchainGasPaymaster * @notice Manages payments on a source chain to cover gas costs of relaying * messages to destination chains. */ contract InterchainGasPaymaster is IInterchainGasPaymaster, IPostDispatchHook, IGasOracle, OwnableUpgradeable { using Address for address payable; using Message for bytes; using IGPMetadata for bytes; // ============ Constants ============ /// @notice The scale of gas oracle token exchange rates. uint256 internal constant TOKEN_EXCHANGE_RATE_SCALE = 1e10; /// @notice default for user call if metadata not provided uint256 internal immutable DEFAULT_GAS_USAGE = 69_420; // ============ Public Storage ============ /// @notice Keyed by remote domain, the gas oracle to use for the domain. mapping(uint32 => IGasOracle) public gasOracles; /// @notice The benficiary that can receive native tokens paid into this contract. address public beneficiary; // ============ Events ============ /** * @notice Emitted when the gas oracle for a remote domain is set. * @param remoteDomain The remote domain. * @param gasOracle The gas oracle. */ event GasOracleSet(uint32 indexed remoteDomain, address gasOracle); /** * @notice Emitted when the beneficiary is set. * @param beneficiary The new beneficiary. */ event BeneficiarySet(address beneficiary); struct GasOracleConfig { uint32 remoteDomain; address gasOracle; } // ============ External Functions ============ /** * @param _owner The owner of the contract. * @param _beneficiary The beneficiary. */ function initialize(address _owner, address _beneficiary) public initializer { __Ownable_init(); _transferOwnership(_owner); _setBeneficiary(_beneficiary); } /** * @notice pay for gas as a hook * @param metadata The metadata as gasConfig. * @param message The message to pay for. */ function postDispatch(bytes calldata metadata, bytes calldata message) external payable override { uint256 gasLimit = metadata.gasLimit(DEFAULT_GAS_USAGE); address refundAddress = metadata.refundAddress(message.senderAddress()); payForGas(message.id(), message.destination(), gasLimit, refundAddress); } /** * @notice Quote gas payment for a hook call. * @param metadata The metadata as gasConfig. * @param message The message to pay for. */ function quoteDispatch(bytes calldata metadata, bytes calldata message) external view override returns (uint256) { uint256 gasLimit = metadata.gasLimit(DEFAULT_GAS_USAGE); return quoteGasPayment(message.destination(), gasLimit); } /** * @notice Transfers the entire native token balance to the beneficiary. * @dev The beneficiary must be able to receive native tokens. */ function claim() external { // Transfer the entire balance to the beneficiary. (bool success, ) = beneficiary.call{value: address(this).balance}(""); require(success, "!transfer"); } /** * @notice Sets the gas oracles for remote domains specified in the config array. * @param _configs An array of configs including the remote domain and gas oracles to set. */ function setGasOracles(GasOracleConfig[] calldata _configs) external onlyOwner { uint256 _len = _configs.length; for (uint256 i = 0; i < _len; i++) { _setGasOracle(_configs[i].remoteDomain, _configs[i].gasOracle); } } /** * @notice Sets the beneficiary. * @param _beneficiary The new beneficiary. */ function setBeneficiary(address _beneficiary) external onlyOwner { _setBeneficiary(_beneficiary); } // ============ Public Functions ============ /** * @notice Deposits msg.value as a payment for the relaying of a message * to its destination chain. * @dev Overpayment will result in a refund of native tokens to the _refundAddress. * Callers should be aware that this may present reentrancy issues. * @param _messageId The ID of the message to pay for. * @param _destinationDomain The domain of the message's destination chain. * @param _gasAmount The amount of destination gas to pay for. * @param _refundAddress The address to refund any overpayment to. */ function payForGas( bytes32 _messageId, uint32 _destinationDomain, uint256 _gasAmount, address _refundAddress ) public payable override { uint256 _requiredPayment = quoteGasPayment( _destinationDomain, _gasAmount ); require( msg.value >= _requiredPayment, "insufficient interchain gas payment" ); uint256 _overpayment = msg.value - _requiredPayment; if (_overpayment > 0) { payable(_refundAddress).sendValue(_overpayment); } emit GasPayment(_messageId, _gasAmount, _requiredPayment); } /** * @notice Quotes the amount of native tokens to pay for interchain gas. * @param _destinationDomain The domain of the message's destination chain. * @param _gasAmount The amount of destination gas to pay for. * @return The amount of native tokens required to pay for interchain gas. */ function quoteGasPayment(uint32 _destinationDomain, uint256 _gasAmount) public view virtual override returns (uint256) { // Get the gas data for the destination domain. ( uint128 _tokenExchangeRate, uint128 _gasPrice ) = getExchangeRateAndGasPrice(_destinationDomain); // The total cost quoted in destination chain's native token. uint256 _destinationGasCost = _gasAmount * uint256(_gasPrice); // Convert to the local native token. return (_destinationGasCost * _tokenExchangeRate) / TOKEN_EXCHANGE_RATE_SCALE; } /** * @notice Gets the token exchange rate and gas price from the configured gas oracle * for a given destination domain. * @param _destinationDomain The destination domain. * @return tokenExchangeRate The exchange rate of the remote native token quoted in the local native token. * @return gasPrice The gas price on the remote chain. */ function getExchangeRateAndGasPrice(uint32 _destinationDomain) public view override returns (uint128 tokenExchangeRate, uint128 gasPrice) { IGasOracle _gasOracle = gasOracles[_destinationDomain]; require( address(_gasOracle) != address(0), string.concat( "Configured IGP doesn't support domain ", Strings.toString(_destinationDomain) ) ); return _gasOracle.getExchangeRateAndGasPrice(_destinationDomain); } // ============ Internal Functions ============ /** * @notice Sets the beneficiary. * @param _beneficiary The new beneficiary. */ function _setBeneficiary(address _beneficiary) internal { beneficiary = _beneficiary; emit BeneficiarySet(_beneficiary); } /** * @notice Sets the gas oracle for a remote domain. * @param _remoteDomain The remote domain. * @param _gasOracle The gas oracle. */ function _setGasOracle(uint32 _remoteDomain, address _gasOracle) internal { gasOracles[_remoteDomain] = IGasOracle(_gasOracle); emit GasOracleSet(_remoteDomain, _gasOracle); } }