Contract Source Code:

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "arb-bridge-eth/contracts/libraries/Whitelist.sol";

import { ArbitrumEnabledToken } from "../ICustomToken.sol";
import "../L1ArbitrumMessenger.sol";
import "../../libraries/gateway/GatewayRouter.sol";
import "../../arbitrum/gateway/L2GatewayRouter.sol";
import "../../libraries/ERC165.sol";
import "./IL1GatewayRouter.sol";
import "./IL1ArbitrumGateway.sol";

/**
 * @title Handles deposits from Erhereum into Arbitrum. Tokens are routered to their appropriate L1 gateway (Router itself also conforms to the Gateway itnerface).
 * @notice Router also serves as an L1-L2 token address oracle.
 */
contract L1GatewayRouter is
    WhitelistConsumer,
    L1ArbitrumMessenger,
    GatewayRouter,
    ERC165,
    IL1GatewayRouter
{
    address public override owner;
    address public override inbox;

    modifier onlyOwner() {
        require(msg.sender == owner, "ONLY_OWNER");
        _;
    }

    function initialize(
        address _owner,
        address _defaultGateway,
        address, // was _whitelist, now unused
        address _counterpartGateway,
        address _inbox
    ) public {
        GatewayRouter._initialize(_counterpartGateway, address(0), _defaultGateway);
        owner = _owner;
        WhitelistConsumer.whitelist = address(0);
        inbox = _inbox;
    }

    function setDefaultGateway(
        address newL1DefaultGateway,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        uint256 _maxSubmissionCost
    ) external payable onlyOwner returns (uint256) {
        defaultGateway = newL1DefaultGateway;

        emit DefaultGatewayUpdated(newL1DefaultGateway);

        address l2NewDefaultGateway;

        if (newL1DefaultGateway != address(0)) {
            l2NewDefaultGateway = TokenGateway(newL1DefaultGateway).counterpartGateway();
        }

        bytes memory data = abi.encodeWithSelector(
            L2GatewayRouter.setDefaultGateway.selector,
            l2NewDefaultGateway
        );

        return
            sendTxToL2(
                inbox,
                counterpartGateway,
                msg.sender,
                msg.value,
                0,
                L2GasParams({
                    _maxSubmissionCost: _maxSubmissionCost,
                    _maxGas: _maxGas,
                    _gasPriceBid: _gasPriceBid
                }),
                data
            );
    }

    function setOwner(address newOwner) external onlyOwner {
        require(newOwner != address(0), "INVALID_OWNER");
        // set newOwner to address(1) to disable owner and keep `initialize` safe
        owner = newOwner;
    }

    function _setGateways(
        address[] memory _token,
        address[] memory _gateway,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        uint256 _maxSubmissionCost,
        address _creditBackAddress
    ) internal returns (uint256) {
        require(_token.length == _gateway.length, "WRONG_LENGTH");

        for (uint256 i = 0; i < _token.length; i++) {
            l1TokenToGateway[_token[i]] = _gateway[i];
            emit GatewaySet(_token[i], _gateway[i]);
            // overwrite memory so the L2 router receives the L2 address of each gateway
            if (_gateway[i] != address(0) && _gateway[i] != DISABLED) {
                // if we are assigning a gateway to the token, the address oracle of the gateway
                // must return something other than the 0 address
                // this check helps avoid misconfiguring gateways
                require(
                    TokenGateway(_gateway[i]).calculateL2TokenAddress(_token[i]) != address(0),
                    "TOKEN_NOT_HANDLED_BY_GATEWAY"
                );
                _gateway[i] = TokenGateway(_gateway[i]).counterpartGateway();
            }
        }

        bytes memory data = abi.encodeWithSelector(
            L2GatewayRouter.setGateway.selector,
            _token,
            _gateway
        );

        return
            sendTxToL2(
                inbox,
                counterpartGateway,
                _creditBackAddress,
                msg.value,
                0,
                L2GasParams({
                    _maxSubmissionCost: _maxSubmissionCost,
                    _maxGas: _maxGas,
                    _gasPriceBid: _gasPriceBid
                }),
                data
            );
    }

    /**
     * @notice Allows L1 Token contract to trustlessly register its gateway. (other setGateway method allows excess eth recovery from _maxSubmissionCost and is recommended)
     * @param _gateway l1 gateway address
     * @param _maxGas max gas for L2 retryable exrecution
     * @param _gasPriceBid gas price for L2 retryable ticket
     * @param  _maxSubmissionCost base submission cost  L2 retryable tick3et
     * @return Retryable ticket ID
     */
    function setGateway(
        address _gateway,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        uint256 _maxSubmissionCost
    ) external payable override returns (uint256) {
        return setGateway(_gateway, _maxGas, _gasPriceBid, _maxSubmissionCost, msg.sender);
    }

    /**
     * @notice Allows L1 Token contract to trustlessly register its gateway.
     * @param _gateway l1 gateway address
     * @param _maxGas max gas for L2 retryable exrecution
     * @param _gasPriceBid gas price for L2 retryable ticket
     * @param  _maxSubmissionCost base submission cost  L2 retryable tick3et
     * @param _creditBackAddress address for crediting back overpayment of _maxSubmissionCost
     * @return Retryable ticket ID
     */
    function setGateway(
        address _gateway,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        uint256 _maxSubmissionCost,
        address _creditBackAddress
    ) public payable override returns (uint256) {
        require(
            ArbitrumEnabledToken(msg.sender).isArbitrumEnabled() == uint8(0xa4b1),
            "NOT_ARB_ENABLED"
        );
        require(_gateway.isContract(), "NOT_TO_CONTRACT");

        address currGateway = getGateway(msg.sender);
        if (currGateway != address(0) && currGateway != defaultGateway) {
            // if gateway is already set to a non-default gateway, don't allow it to set a different gateway
            require(currGateway == _gateway, "NO_UPDATE_TO_DIFFERENT_ADDR");
        }

        address[] memory _tokenArr = new address[](1);
        _tokenArr[0] = address(msg.sender);

        address[] memory _gatewayArr = new address[](1);
        _gatewayArr[0] = _gateway;

        return
            _setGateways(
                _tokenArr,
                _gatewayArr,
                _maxGas,
                _gasPriceBid,
                _maxSubmissionCost,
                _creditBackAddress
            );
    }

    function setGateways(
        address[] memory _token,
        address[] memory _gateway,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        uint256 _maxSubmissionCost
    ) external payable onlyOwner returns (uint256) {
        // it is assumed that token and gateway are both contracts
        // require(_token[i].isContract() && _gateway[i].isContract(), "NOT_CONTRACT");
        return
            _setGateways(_token, _gateway, _maxGas, _gasPriceBid, _maxSubmissionCost, msg.sender);
    }

    function outboundTransfer(
        address _token,
        address _to,
        uint256 _amount,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        bytes calldata _data
    ) public payable override(GatewayRouter, ITokenGateway) returns (bytes memory) {
        return super.outboundTransfer(_token, _to, _amount, _maxGas, _gasPriceBid, _data);
    }

    /**
     * @notice Deposit ERC20 token from Ethereum into Arbitrum using the registered or otherwise default gateway
     * @dev Some legacy gateway might not have the outboundTransferCustomRefund method and will revert, in such case use outboundTransfer instead
     *      L2 address alias will not be applied to the following types of addresses on L1:
     *      - an externally-owned account
     *      - a contract in construction
     *      - an address where a contract will be created
     *      - an address where a contract lived, but was destroyed
     * @param _token L1 address of ERC20
     * @param _refundTo Account, or its L2 alias if it have code in L1, to be credited with excess gas refund in L2
     * @param _to Account to be credited with the tokens in the L2 (can be the user's L2 account or a contract), not subject to L2 aliasing
                  This account, or its L2 alias if it have code in L1, will also be able to cancel the retryable ticket and receive callvalue refund
     * @param _amount Token Amount
     * @param _maxGas Max gas deducted from user's L2 balance to cover L2 execution
     * @param _gasPriceBid Gas price for L2 execution
     * @param _data encoded data from router and user
     * @return res abi encoded inbox sequence number
     */
    function outboundTransferCustomRefund(
        address _token,
        address _refundTo,
        address _to,
        uint256 _amount,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        bytes calldata _data
    ) public payable override returns (bytes memory) {
        address gateway = getGateway(_token);
        bytes memory gatewayData = GatewayMessageHandler.encodeFromRouterToGateway(
            msg.sender,
            _data
        );

        emit TransferRouted(_token, msg.sender, _to, gateway);
        // here we use `IL1ArbitrumGateway` since we don't assume all ITokenGateway implements `outboundTransferCustomRefund`
        return
            IL1ArbitrumGateway(gateway).outboundTransferCustomRefund{ value: msg.value }(
                _token,
                _refundTo,
                _to,
                _amount,
                _maxGas,
                _gasPriceBid,
                gatewayData
            );
    }

    modifier onlyCounterpartGateway() override {
        // don't expect messages from L2 router
        revert("ONLY_COUNTERPART_GATEWAY");
        _;
    }

    function supportsInterface(bytes4 interfaceId)
        public
        view
        override(ERC165, IERC165)
        returns (bool)
    {
        // registering interfaces that is added after arb-bridge-peripherals >1.0.11
        // using function selector instead of single function interfaces to reduce bloat
        return
            interfaceId == this.outboundTransferCustomRefund.selector ||
            super.supportsInterface(interfaceId);
    }
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

abstract contract WhitelistConsumer {
    address public whitelist;

    event WhitelistSourceUpdated(address newSource);

    modifier onlyWhitelisted() {
        if (whitelist != address(0)) {
            require(Whitelist(whitelist).isAllowed(msg.sender), "NOT_WHITELISTED");
        }
        _;
    }

    function updateWhitelistSource(address newSource) external {
        require(msg.sender == whitelist, "NOT_FROM_LIST");
        whitelist = newSource;
        emit WhitelistSourceUpdated(newSource);
    }
}

contract Whitelist {
    address public owner;
    mapping(address => bool) public isAllowed;

    event OwnerUpdated(address newOwner);
    event WhitelistUpgraded(address newWhitelist, address[] targets);

    constructor() public {
        owner = msg.sender;
    }

    modifier onlyOwner() {
        require(msg.sender == owner, "ONLY_OWNER");
        _;
    }

    function setOwner(address newOwner) external onlyOwner {
        owner = newOwner;
        emit OwnerUpdated(newOwner);
    }

    function setWhitelist(address[] memory user, bool[] memory val) external onlyOwner {
        require(user.length == val.length, "INVALID_INPUT");

        for (uint256 i = 0; i < user.length; i++) {
            isAllowed[user[i]] = val[i];
        }
    }

    // set new whitelist to address(0) to disable whitelist
    function triggerConsumers(address newWhitelist, address[] memory targets) external onlyOwner {
        for (uint256 i = 0; i < targets.length; i++) {
            WhitelistConsumer(targets[i]).updateWhitelistSource(newWhitelist);
        }
        emit WhitelistUpgraded(newWhitelist, targets);
    }
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;

interface ArbitrumEnabledToken {
    /// @notice should return `0xa4b1` if token is enabled for arbitrum gateways
    function isArbitrumEnabled() external view returns (uint8);
}

/**
 * @title Minimum expected interface for L1 custom token (see TestCustomTokenL1.sol for an example implementation)
 */
interface ICustomToken is ArbitrumEnabledToken {
    /**
     * @notice Should make an external call to EthERC20Bridge.registerCustomL2Token
     */
    function registerTokenOnL2(
        address l2CustomTokenAddress,
        uint256 maxSubmissionCostForCustomBridge,
        uint256 maxSubmissionCostForRouter,
        uint256 maxGasForCustomBridge,
        uint256 maxGasForRouter,
        uint256 gasPriceBid,
        uint256 valueForGateway,
        uint256 valueForRouter,
        address creditBackAddress
    ) external payable;

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    function balanceOf(address account) external view returns (uint256);
}

interface L1MintableToken is ICustomToken {
    function bridgeMint(address account, uint256 amount) external;
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "arb-bridge-eth/contracts/bridge/interfaces/IInbox.sol";
import "arb-bridge-eth/contracts/bridge/interfaces/IOutbox.sol";

/// @notice L1 utility contract to assist with L1 <=> L2 interactions
/// @dev this is an abstract contract instead of library so the functions can be easily overriden when testing
abstract contract L1ArbitrumMessenger {
    event TxToL2(address indexed _from, address indexed _to, uint256 indexed _seqNum, bytes _data);

    struct L2GasParams {
        uint256 _maxSubmissionCost;
        uint256 _maxGas;
        uint256 _gasPriceBid;
    }

    function sendTxToL2CustomRefund(
        address _inbox,
        address _to,
        address _refundTo,
        address _user,
        uint256 _l1CallValue,
        uint256 _l2CallValue,
        L2GasParams memory _l2GasParams,
        bytes memory _data
    ) internal returns (uint256) {
        // alternative function entry point when struggling with the stack size
        return
            sendTxToL2CustomRefund(
                _inbox,
                _to,
                _refundTo,
                _user,
                _l1CallValue,
                _l2CallValue,
                _l2GasParams._maxSubmissionCost,
                _l2GasParams._maxGas,
                _l2GasParams._gasPriceBid,
                _data
            );
    }

    function sendTxToL2(
        address _inbox,
        address _to,
        address _user,
        uint256 _l1CallValue,
        uint256 _l2CallValue,
        L2GasParams memory _l2GasParams,
        bytes memory _data
    ) internal returns (uint256) {
        // alternative function entry point when struggling with the stack size
        return
            sendTxToL2(
                _inbox,
                _to,
                _user,
                _l1CallValue,
                _l2CallValue,
                _l2GasParams._maxSubmissionCost,
                _l2GasParams._maxGas,
                _l2GasParams._gasPriceBid,
                _data
            );
    }

    function sendTxToL2CustomRefund(
        address _inbox,
        address _to,
        address _refundTo,
        address _user,
        uint256 _l1CallValue,
        uint256 _l2CallValue,
        uint256 _maxSubmissionCost,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        bytes memory _data
    ) internal returns (uint256) {
        uint256 seqNum = IInbox(_inbox).createRetryableTicket{ value: _l1CallValue }(
            _to,
            _l2CallValue,
            _maxSubmissionCost,
            _refundTo, // only refund excess fee to the custom address
            _user, // user can cancel the retryable and receive call value refund
            _maxGas,
            _gasPriceBid,
            _data
        );
        emit TxToL2(_user, _to, seqNum, _data);
        return seqNum;
    }

    function sendTxToL2(
        address _inbox,
        address _to,
        address _user,
        uint256 _l1CallValue,
        uint256 _l2CallValue,
        uint256 _maxSubmissionCost,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        bytes memory _data
    ) internal returns (uint256) {
        return
            sendTxToL2CustomRefund(
                _inbox,
                _to,
                _user,
                _user,
                _l1CallValue,
                _l2CallValue,
                _maxSubmissionCost,
                _maxGas,
                _gasPriceBid,
                _data
            );
    }

    function getBridge(address _inbox) internal view returns (IBridge) {
        return IInbox(_inbox).bridge();
    }

    /// @dev the l2ToL1Sender behaves as the tx.origin, the msg.sender should be validated to protect against reentrancies
    function getL2ToL1Sender(address _inbox) internal view returns (address) {
        IOutbox outbox = IOutbox(getBridge(_inbox).activeOutbox());
        address l2ToL1Sender = outbox.l2ToL1Sender();

        require(l2ToL1Sender != address(0), "NO_SENDER");
        return l2ToL1Sender;
    }
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "arb-bridge-eth/contracts/libraries/ProxyUtil.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "./TokenGateway.sol";
import "./GatewayMessageHandler.sol";
import "./IGatewayRouter.sol";

/**
 * @title Common interface for L1 and L2 Gateway Routers
 */
abstract contract GatewayRouter is TokenGateway, IGatewayRouter {
    using Address for address;

    address internal constant ZERO_ADDR = address(0);
    address internal constant DISABLED = address(1);

    mapping(address => address) public l1TokenToGateway;
    address public override defaultGateway;

    event TransferRouted(
        address indexed token,
        address indexed _userFrom,
        address indexed _userTo,
        address gateway
    );

    event GatewaySet(address indexed l1Token, address indexed gateway);
    event DefaultGatewayUpdated(address newDefaultGateway);

    function postUpgradeInit() external {
        // it is assumed the L2 Arbitrum Gateway contract is behind a Proxy controlled by a proxy admin
        // this function can only be called by the proxy admin contract
        address proxyAdmin = ProxyUtil.getProxyAdmin();
        require(msg.sender == proxyAdmin, "NOT_FROM_ADMIN");
        // this has no other logic since the current upgrade doesn't require this logic
    }

    function _initialize(
        address _counterpartGateway,
        address _router,
        address _defaultGateway
    ) internal {
        // if you are a router, you can't have a router
        require(_router == address(0), "BAD_ROUTER");
        TokenGateway._initialize(_counterpartGateway, _router);
        // default gateway can have 0 address
        defaultGateway = _defaultGateway;
    }

    function finalizeInboundTransfer(
        address, /* _token */
        address, /* _from */
        address, /* _to */
        uint256, /* _amount */
        bytes calldata /* _data */
    ) external payable virtual override {
        revert("ONLY_OUTBOUND_ROUTER");
    }

    function outboundTransfer(
        address _token,
        address _to,
        uint256 _amount,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        bytes calldata _data
    ) public payable virtual override returns (bytes memory) {
        // this function is kept instead of delegating to outboundTransferCustomRefund to allow
        // compatibility with older gateways that did not implement outboundTransferCustomRefund
        address gateway = getGateway(_token);
        bytes memory gatewayData = GatewayMessageHandler.encodeFromRouterToGateway(
            msg.sender,
            _data
        );

        emit TransferRouted(_token, msg.sender, _to, gateway);
        return
            ITokenGateway(gateway).outboundTransfer{ value: msg.value }(
                _token,
                _to,
                _amount,
                _maxGas,
                _gasPriceBid,
                gatewayData
            );
    }

    function getOutboundCalldata(
        address _token,
        address _from,
        address _to,
        uint256 _amount,
        bytes memory _data
    ) public view virtual override returns (bytes memory) {
        address gateway = getGateway(_token);
        return TokenGateway(gateway).getOutboundCalldata(_token, _from, _to, _amount, _data);
    }

    function getGateway(address _token) public view virtual override returns (address gateway) {
        gateway = l1TokenToGateway[_token];

        if (gateway == ZERO_ADDR) {
            // if no gateway value set, use default gateway
            gateway = defaultGateway;
        }

        if (gateway == DISABLED || !gateway.isContract()) {
            // not a valid gateway
            return ZERO_ADDR;
        }

        return gateway;
    }

    function calculateL2TokenAddress(address l1ERC20)
        public
        view
        virtual
        override(TokenGateway, ITokenGateway)
        returns (address)
    {
        address gateway = getGateway(l1ERC20);
        if (gateway == ZERO_ADDR) {
            return ZERO_ADDR;
        }
        return TokenGateway(gateway).calculateL2TokenAddress(l1ERC20);
    }
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "../../libraries/gateway/GatewayRouter.sol";
import "../../ethereum/gateway/L1GatewayRouter.sol";
import "../L2ArbitrumMessenger.sol";
import "arb-bridge-eth/contracts/libraries/AddressAliasHelper.sol";

/**
 * @title Handles withdrawals from Ethereum into Arbitrum. Tokens are routered to their appropriate L2 gateway (Router itself also conforms to the Gateway interface).
 * @notice Router also serves as an L2-L1 token address oracle.
 */
contract L2GatewayRouter is GatewayRouter, L2ArbitrumMessenger {
    modifier onlyCounterpartGateway() override {
        require(
            msg.sender == AddressAliasHelper.applyL1ToL2Alias(counterpartGateway),
            "ONLY_COUNTERPART_GATEWAY"
        );
        _;
    }

    function initialize(address _counterpartGateway, address _defaultGateway) public {
        GatewayRouter._initialize(_counterpartGateway, address(0), _defaultGateway);
    }

    function setGateway(address[] memory _l1Token, address[] memory _gateway)
        external
        onlyCounterpartGateway
    {
        // counterpart gateway (L1 router) should never allow wrong lengths
        assert(_l1Token.length == _gateway.length);

        for (uint256 i = 0; i < _l1Token.length; i++) {
            l1TokenToGateway[_l1Token[i]] = _gateway[i];
            emit GatewaySet(_l1Token[i], _gateway[i]);
        }
    }

    function outboundTransfer(
        address _l1Token,
        address _to,
        uint256 _amount,
        bytes calldata _data
    ) public payable returns (bytes memory) {
        return outboundTransfer(_l1Token, _to, _amount, 0, 0, _data);
    }

    function setDefaultGateway(address newL2DefaultGateway) external onlyCounterpartGateway {
        defaultGateway = newL2DefaultGateway;
        emit DefaultGatewayUpdated(newL2DefaultGateway);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

// With pragma modification to support ^0.6.11
// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/release-v4.6/contracts/utils/introspection/ERC165.sol

pragma solidity ^0.6.11;

import "./IERC165.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;

import "../../libraries/gateway/ITokenGateway.sol";
import "../../libraries/IERC165.sol";

/**
 * @title Handles deposits from Erhereum into Arbitrum. Tokens are routered to their appropriate L1 gateway (Router itself also conforms to the Gateway itnerface).
 * @notice Router also serves as an L1-L2 token address oracle.
 */
interface IL1GatewayRouter is ITokenGateway, IERC165 {
    /**
     * @notice Deposit ERC20 token from Ethereum into Arbitrum using the registered or otherwise default gateway
     * @dev Some legacy gateway might not have the outboundTransferCustomRefund method and will revert, in such case use outboundTransfer instead
     *      L2 address alias will not be applied to the following types of addresses on L1:
     *      - an externally-owned account
     *      - a contract in construction
     *      - an address where a contract will be created
     *      - an address where a contract lived, but was destroyed
     * @param _token L1 address of ERC20
     * @param _refundTo Account, or its L2 alias if it have code in L1, to be credited with excess gas refund in L2
     * @param _to Account to be credited with the tokens in the L2 (can be the user's L2 account or a contract), not subject to L2 aliasing
                  This account, or its L2 alias if it have code in L1, will also be able to cancel the retryable ticket and receive callvalue refund
     * @param _amount Token Amount
     * @param _maxGas Max gas deducted from user's L2 balance to cover L2 execution
     * @param _gasPriceBid Gas price for L2 execution
     * @param _data encoded data from router and user
     * @return res abi encoded inbox sequence number
     */
    function outboundTransferCustomRefund(
        address _token,
        address _refundTo,
        address _to,
        uint256 _amount,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        bytes calldata _data
    ) external payable returns (bytes memory);

    /**
     * @notice Allows L1 Token contract to trustlessly register its gateway.
     * @param _gateway l1 gateway address
     * @param _maxGas max gas for L2 retryable exrecution
     * @param _gasPriceBid gas price for L2 retryable ticket
     * @param  _maxSubmissionCost base submission cost  L2 retryable tick3et
     * @param _creditBackAddress address for crediting back overpayment of _maxSubmissionCost
     * @return Retryable ticket ID
     */
    function setGateway(
        address _gateway,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        uint256 _maxSubmissionCost,
        address _creditBackAddress
    ) external payable returns (uint256);

    /**
     * @notice Allows L1 Token contract to trustlessly register its gateway. (other setGateway method allows excess eth recovery from _maxSubmissionCost and is recommended)
     * @param _gateway l1 gateway address
     * @param _maxGas max gas for L2 retryable exrecution
     * @param _gasPriceBid gas price for L2 retryable ticket
     * @param  _maxSubmissionCost base submission cost  L2 retryable tick3et
     * @return Retryable ticket ID
     */
    function setGateway(
        address _gateway,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        uint256 _maxSubmissionCost
    ) external payable returns (uint256);

    function owner() external view returns (address);

    function inbox() external view returns (address);
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;

import "../../libraries/gateway/ITokenGateway.sol";
import "../../libraries/IERC165.sol";

/**
 * @title Common interface for gatways on L1 messaging to Arbitrum.
 */
interface IL1ArbitrumGateway is ITokenGateway, IERC165 {
    function inbox() external view returns (address);

    /**
     * @notice Deposit ERC20 token from Ethereum into Arbitrum. If L2 side hasn't been deployed yet, includes name/symbol/decimals data for initial L2 deploy. Initiate by GatewayRouter.
     * @dev L2 address alias will not be applied to the following types of addresses on L1:
     *      - an externally-owned account
     *      - a contract in construction
     *      - an address where a contract will be created
     *      - an address where a contract lived, but was destroyed
     * @param _l1Token L1 address of ERC20
     * @param _refundTo Account, or its L2 alias if it have code in L1, to be credited with excess gas refund in L2
     * @param _to Account to be credited with the tokens in the L2 (can be the user's L2 account or a contract), not subject to L2 aliasing
                  This account, or its L2 alias if it have code in L1, will also be able to cancel the retryable ticket and receive callvalue refund
     * @param _amount Token Amount
     * @param _maxGas Max gas deducted from user's L2 balance to cover L2 execution
     * @param _gasPriceBid Gas price for L2 execution
     * @param _data encoded data from router and user
     * @return res abi encoded inbox sequence number
     */
    //  * @param maxSubmissionCost Max gas deducted from user's L2 balance to cover base submission fee
    function outboundTransferCustomRefund(
        address _l1Token,
        address _refundTo,
        address _to,
        uint256 _amount,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        bytes calldata _data
    ) external payable returns (bytes memory);
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;

import "./IBridge.sol";
import "./IMessageProvider.sol";

interface IInbox is IMessageProvider {
    function sendL2Message(bytes calldata messageData) external returns (uint256);

    function sendUnsignedTransaction(
        uint256 maxGas,
        uint256 gasPriceBid,
        uint256 nonce,
        address destAddr,
        uint256 amount,
        bytes calldata data
    ) external returns (uint256);

    function sendContractTransaction(
        uint256 maxGas,
        uint256 gasPriceBid,
        address destAddr,
        uint256 amount,
        bytes calldata data
    ) external returns (uint256);

    function sendL1FundedUnsignedTransaction(
        uint256 maxGas,
        uint256 gasPriceBid,
        uint256 nonce,
        address destAddr,
        bytes calldata data
    ) external payable returns (uint256);

    function sendL1FundedContractTransaction(
        uint256 maxGas,
        uint256 gasPriceBid,
        address destAddr,
        bytes calldata data
    ) external payable returns (uint256);

    function createRetryableTicket(
        address destAddr,
        uint256 arbTxCallValue,
        uint256 maxSubmissionCost,
        address submissionRefundAddress,
        address valueRefundAddress,
        uint256 maxGas,
        uint256 gasPriceBid,
        bytes calldata data
    ) external payable returns (uint256);

    function unsafeCreateRetryableTicket(
        address destAddr,
        uint256 arbTxCallValue,
        uint256 maxSubmissionCost,
        address submissionRefundAddress,
        address valueRefundAddress,
        uint256 maxGas,
        uint256 gasPriceBid,
        bytes calldata data
    ) external payable returns (uint256);

    function depositEth(uint256 maxSubmissionCost) external payable returns (uint256);

    function bridge() external view returns (IBridge);

    function pauseCreateRetryables() external;

    function unpauseCreateRetryables() external;

    function startRewriteAddress() external;

    function stopRewriteAddress() external;
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;

interface IOutbox {
    event OutboxEntryCreated(
        uint256 indexed batchNum,
        uint256 outboxEntryIndex,
        bytes32 outputRoot,
        uint256 numInBatch
    );
    event OutBoxTransactionExecuted(
        address indexed destAddr,
        address indexed l2Sender,
        uint256 indexed outboxEntryIndex,
        uint256 transactionIndex
    );

    function l2ToL1Sender() external view returns (address);

    function l2ToL1Block() external view returns (uint256);

    function l2ToL1EthBlock() external view returns (uint256);

    function l2ToL1Timestamp() external view returns (uint256);

    function l2ToL1BatchNum() external view returns (uint256);

    function l2ToL1OutputId() external view returns (bytes32);

    function processOutgoingMessages(bytes calldata sendsData, uint256[] calldata sendLengths)
        external;

    function outboxEntryExists(uint256 batchNum) external view returns (bool);
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;

interface IBridge {
    event MessageDelivered(
        uint256 indexed messageIndex,
        bytes32 indexed beforeInboxAcc,
        address inbox,
        uint8 kind,
        address sender,
        bytes32 messageDataHash
    );

    event BridgeCallTriggered(
        address indexed outbox,
        address indexed destAddr,
        uint256 amount,
        bytes data
    );

    event InboxToggle(address indexed inbox, bool enabled);

    event OutboxToggle(address indexed outbox, bool enabled);

    function deliverMessageToInbox(
        uint8 kind,
        address sender,
        bytes32 messageDataHash
    ) external payable returns (uint256);

    function executeCall(
        address destAddr,
        uint256 amount,
        bytes calldata data
    ) external returns (bool success, bytes memory returnData);

    // These are only callable by the admin
    function setInbox(address inbox, bool enabled) external;

    function setOutbox(address inbox, bool enabled) external;

    // View functions

    function activeOutbox() external view returns (address);

    function allowedInboxes(address inbox) external view returns (bool);

    function allowedOutboxes(address outbox) external view returns (bool);

    function inboxAccs(uint256 index) external view returns (bytes32);

    function messageCount() external view returns (uint256);
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;

interface IMessageProvider {
    event InboxMessageDelivered(uint256 indexed messageNum, bytes data);

    event InboxMessageDeliveredFromOrigin(uint256 indexed messageNum);
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

library ProxyUtil {
    function getProxyAdmin() internal view returns (address admin) {
        // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.4.0/contracts/proxy/TransparentUpgradeableProxy.sol#L48
        // Storage slot with the admin of the proxy contract.
        // This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
        bytes32 slot = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
        assembly {
            admin := sload(slot)
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "./ITokenGateway.sol";
import "@openzeppelin/contracts/utils/Address.sol";

abstract contract TokenGateway is ITokenGateway {
    using Address for address;

    address public counterpartGateway;
    address public router;

    // This modifier is overriden in gateways to validate the message sender
    // For L1 to L2 messages need to be validated against the aliased counterpartGateway
    // For L2 to L1 messages need to be validated against the bridge and L2ToL1Sender
    // prettier-ignore
    modifier onlyCounterpartGateway() virtual;

    function _initialize(address _counterpartGateway, address _router) internal virtual {
        // This initializes internal variables of the abstract contract it can be chained together with other functions.
        // It is virtual so subclasses can override or wrap around this logic.
        // An example where this is useful is different subclasses that validate the router address differently
        require(_counterpartGateway != address(0), "INVALID_COUNTERPART");
        require(counterpartGateway == address(0), "ALREADY_INIT");
        counterpartGateway = _counterpartGateway;
        router = _router;
    }

    function isRouter(address _target) internal view returns (bool isTargetRouter) {
        return _target == router;
    }

    /**
     * @notice Calculate the address used when bridging an ERC20 token
     * @dev the L1 and L2 address oracles may not always be in sync.
     * For example, a custom token may have been registered but not deploy or the contract self destructed.
     * @param l1ERC20 address of L1 token
     * @return L2 address of a bridged ERC20 token
     */
    function calculateL2TokenAddress(address l1ERC20)
        public
        view
        virtual
        override
        returns (address);
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

/// @notice this library manages encoding and decoding of gateway communication
library GatewayMessageHandler {
    // these are for communication from L1 to L2 gateway

    function encodeToL2GatewayMsg(bytes memory gatewayData, bytes memory callHookData)
        internal
        pure
        returns (bytes memory res)
    {
        res = abi.encode(gatewayData, callHookData);
    }

    function parseFromL1GatewayMsg(bytes calldata _data)
        internal
        pure
        returns (bytes memory gatewayData, bytes memory callHookData)
    {
        // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
        (gatewayData, callHookData) = abi.decode(_data, (bytes, bytes));
    }

    // these are for communication from L2 to L1 gateway

    function encodeFromL2GatewayMsg(uint256 exitNum, bytes memory callHookData)
        internal
        pure
        returns (bytes memory res)
    {
        res = abi.encode(exitNum, callHookData);
    }

    function parseToL1GatewayMsg(bytes calldata _data)
        internal
        pure
        returns (uint256 exitNum, bytes memory callHookData)
    {
        // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
        (exitNum, callHookData) = abi.decode(_data, (uint256, bytes));
    }

    // these are for communication from router to gateway

    function encodeFromRouterToGateway(address _from, bytes calldata _data)
        internal
        pure
        returns (bytes memory res)
    {
        // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
        return abi.encode(_from, _data);
    }

    function parseFromRouterToGateway(bytes calldata _data)
        internal
        pure
        returns (address, bytes memory res)
    {
        // abi decode may revert, but the encoding is done by L1 gateway, so we trust it
        return abi.decode(_data, (address, bytes));
    }
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "arb-bridge-eth/contracts/libraries/ProxyUtil.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "./TokenGateway.sol";
import "./GatewayMessageHandler.sol";

/**
 * @title Common interface for L1 and L2 Gateway Routers
 */
interface IGatewayRouter is ITokenGateway {
    function defaultGateway() external view returns (address gateway);

    event TransferRouted(
        address indexed token,
        address indexed _userFrom,
        address indexed _userTo,
        address gateway
    );

    event GatewaySet(address indexed l1Token, address indexed gateway);
    event DefaultGatewayUpdated(address newDefaultGateway);

    function getGateway(address _token) external view returns (address gateway);
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;

interface ITokenGateway {
    /// @notice event deprecated in favor of DepositInitiated and WithdrawalInitiated
    // event OutboundTransferInitiated(
    //     address token,
    //     address indexed _from,
    //     address indexed _to,
    //     uint256 indexed _transferId,
    //     uint256 _amount,
    //     bytes _data
    // );

    /// @notice event deprecated in favor of DepositFinalized and WithdrawalFinalized
    // event InboundTransferFinalized(
    //     address token,
    //     address indexed _from,
    //     address indexed _to,
    //     uint256 indexed _transferId,
    //     uint256 _amount,
    //     bytes _data
    // );

    function outboundTransfer(
        address _token,
        address _to,
        uint256 _amount,
        uint256 _maxGas,
        uint256 _gasPriceBid,
        bytes calldata _data
    ) external payable returns (bytes memory);

    function finalizeInboundTransfer(
        address _token,
        address _from,
        address _to,
        uint256 _amount,
        bytes calldata _data
    ) external payable;

    /**
     * @notice Calculate the address used when bridging an ERC20 token
     * @dev the L1 and L2 address oracles may not always be in sync.
     * For example, a custom token may have been registered but not deploy or the contract self destructed.
     * @param l1ERC20 address of L1 token
     * @return L2 address of a bridged ERC20 token
     */
    function calculateL2TokenAddress(address l1ERC20) external view returns (address);

    function getOutboundCalldata(
        address _token,
        address _from,
        address _to,
        uint256 _amount,
        bytes memory _data
    ) external view returns (bytes memory);
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "arbos-precompiles/arbos/builtin/ArbSys.sol";

/// @notice L2 utility contract to assist with L1 <=> L2 interactions
/// @dev this is an abstract contract instead of library so the functions can be easily overriden when testing
abstract contract L2ArbitrumMessenger {
    address internal constant ARB_SYS_ADDRESS = address(100);

    event TxToL1(address indexed _from, address indexed _to, uint256 indexed _id, bytes _data);

    function sendTxToL1(
        uint256 _l1CallValue,
        address _from,
        address _to,
        bytes memory _data
    ) internal returns (uint256) {
        uint256 _id = ArbSys(ARB_SYS_ADDRESS).sendTxToL1{ value: _l1CallValue }(_to, _data);
        emit TxToL1(_from, _to, _id, _data);
        return _id;
    }
}

// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2019-2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

library AddressAliasHelper {
    uint160 constant offset = uint160(0x1111000000000000000000000000000000001111);

    /// @notice Utility function that converts the address in the L1 that submitted a tx to
    /// the inbox to the msg.sender viewed in the L2
    /// @param l1Address the address in the L1 that triggered the tx to L2
    /// @return l2Address L2 address as viewed in msg.sender
    function applyL1ToL2Alias(address l1Address) internal pure returns (address l2Address) {
        l2Address = address(uint160(l1Address) + offset);
    }

    /// @notice Utility function that converts the msg.sender viewed in the L2 to the
    /// address in the L1 that submitted a tx to the inbox
    /// @param l2Address L2 address as viewed in msg.sender
    /// @return l1Address the address in the L1 that triggered the tx to L2
    function undoL1ToL2Alias(address l2Address) internal pure returns (address l1Address) {
        l1Address = address(uint160(l2Address) - offset);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

// With pragma modification to allow interface compatibility with >=0.6.9 <0.9.0
// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/release-v4.6/contracts/utils/introspection/IERC165.sol

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

pragma solidity >=0.4.21 <0.9.0;

/**
* @title Precompiled contract that exists in every Arbitrum chain at address(100), 0x0000000000000000000000000000000000000064. Exposes a variety of system-level functionality.
 */
interface ArbSys {
    /**
    * @notice Get internal version number identifying an ArbOS build
    * @return version number as int
     */
    function arbOSVersion() external pure returns (uint);

    function arbChainID() external view returns(uint);

    /**
    * @notice Get Arbitrum block number (distinct from L1 block number; Arbitrum genesis block has block number 0)
    * @return block number as int
     */ 
    function arbBlockNumber() external view returns (uint);

    /** 
    * @notice Send given amount of Eth to dest from sender.
    * This is a convenience function, which is equivalent to calling sendTxToL1 with empty calldataForL1.
    * @param destination recipient address on L1
    * @return unique identifier for this L2-to-L1 transaction.
    */
    function withdrawEth(address destination) external payable returns(uint);

    /** 
    * @notice Send a transaction to L1
    * @param destination recipient address on L1 
    * @param calldataForL1 (optional) calldata for L1 contract call
    * @return a unique identifier for this L2-to-L1 transaction.
    */
    function sendTxToL1(address destination, bytes calldata calldataForL1) external payable returns(uint);

    /** 
    * @notice get the number of transactions issued by the given external account or the account sequence number of the given contract
    * @param account target account
    * @return the number of transactions issued by the given external account or the account sequence number of the given contract
    */
    function getTransactionCount(address account) external view returns(uint256);

    /**  
    * @notice get the value of target L2 storage slot 
    * This function is only callable from address 0 to prevent contracts from being able to call it
    * @param account target account
    * @param index target index of storage slot 
    * @return stotage value for the given account at the given index
    */
    function getStorageAt(address account, uint256 index) external view returns (uint256);

    /**
    * @notice check if current call is coming from l1
    * @return true if the caller of this was called directly from L1
    */
    function isTopLevelCall() external view returns (bool);

    /**
     * @notice check if the caller (of this caller of this) is an aliased L1 contract address
     * @return true iff the caller's address is an alias for an L1 contract address
     */
    function wasMyCallersAddressAliased() external view returns (bool);

    /**
     * @notice return the address of the caller (of this caller of this), without applying L1 contract address aliasing
     * @return address of the caller's caller, without applying L1 contract address aliasing
     */
    function myCallersAddressWithoutAliasing() external view returns (address);

    /**
     * @notice map L1 sender contract address to its L2 alias
     * @param sender sender address
     * @param dest destination address
     * @return aliased sender address
     */
    function mapL1SenderContractAddressToL2Alias(address sender, address dest) external pure returns(address);

    /**
     * @notice get the caller's amount of available storage gas
     * @return amount of storage gas available to the caller
     */
    function getStorageGasAvailable() external view returns(uint);

    event L2ToL1Transaction(address caller, address indexed destination, uint indexed uniqueId,
                            uint indexed batchNumber, uint indexInBatch,
                            uint arbBlockNum, uint ethBlockNum, uint timestamp,
                            uint callvalue, bytes data);
}