feat: forwarders for AVM and OVM networks (#625)

* feat: forwarders for AVM and OVM networks

Signed-off-by: bennett <bennett@umaproject.org>

---------

Signed-off-by: bennett <bennett@umaproject.org>
Co-authored-by: nicholaspai <9457025+nicholaspai@users.noreply.github.com>
Co-authored-by: Matt Rice <matthewcrice32@gmail.com>

contracts/Arbitrum_SpokePool.sol

@@ -6,6 +6,7 @@ pragma solidity ^0.8.19;
 
 import "./SpokePool.sol";
 import "./libraries/CircleCCTPAdapter.sol";
+import { CrossDomainAddressUtils } from "./libraries/CrossDomainAddressUtils.sol";
 import { ArbitrumL2ERC20GatewayLike } from "./interfaces/ArbitrumBridge.sol";
 
 /**
@@ -54,7 +55,7 @@ contract Arbitrum_SpokePool is SpokePool, CircleCCTPAdapter {
     }
 
     modifier onlyFromCrossDomainAdmin() {
-        require(msg.sender == _applyL1ToL2Alias(crossDomainAdmin), "ONLY_COUNTERPART_GATEWAY");
+        require(msg.sender == CrossDomainAddressUtils.applyL1ToL2Alias(crossDomainAdmin), "ONLY_COUNTERPART_GATEWAY");
         _;
     }
 
@@ -111,17 +112,6 @@ contract Arbitrum_SpokePool is SpokePool, CircleCCTPAdapter {
         emit WhitelistedTokens(_l2Token, _l1Token);
     }
 
-    // L1 addresses are transformed during l1->l2 calls.
-    // See https://developer.offchainlabs.com/docs/l1_l2_messages#address-aliasing for more information.
-    // This cannot be pulled directly from Arbitrum contracts because their contracts are not 0.8.X compatible and
-    // this operation takes advantage of overflows, whose behavior changed in 0.8.0.
-    function _applyL1ToL2Alias(address l1Address) internal pure returns (address l2Address) {
-        // Allows overflows as explained above.
-        unchecked {
-            l2Address = address(uint160(l1Address) + uint160(0x1111000000000000000000000000000000001111));
-        }
-    }
-
     // Apply AVM-specific transformation to cross domain admin address on L1.
     function _requireAdminSender() internal override onlyFromCrossDomainAdmin {}
 }

contracts/ZkSync_SpokePool.sol

@@ -2,6 +2,7 @@
 pragma solidity ^0.8.0;
 
 import "./SpokePool.sol";
+import { CrossDomainAddressUtils } from "./libraries/CrossDomainAddressUtils.sol";
 
 // https://github.com/matter-labs/era-contracts/blob/6391c0d7bf6184d7f6718060e3991ba6f0efe4a7/zksync/contracts/bridge/L2ERC20Bridge.sol#L104
 interface ZkBridgeLike {
@@ -62,7 +63,7 @@ contract ZkSync_SpokePool is SpokePool {
     }
 
     modifier onlyFromCrossDomainAdmin() {
-        require(msg.sender == _applyL1ToL2Alias(crossDomainAdmin), "ONLY_COUNTERPART_GATEWAY");
+        require(msg.sender == CrossDomainAddressUtils.applyL1ToL2Alias(crossDomainAdmin), "ONLY_COUNTERPART_GATEWAY");
         _;
     }
 
@@ -118,14 +119,5 @@ contract ZkSync_SpokePool is SpokePool {
         emit SetZkBridge(address(_zkErc20Bridge), oldErc20Bridge);
     }
 
-    // L1 addresses are transformed during l1->l2 calls.
-    // See https://github.com/matter-labs/era-contracts/blob/main/docs/Overview.md#mailboxfacet for more information.
-    // Another source: https://github.com/matter-labs/era-contracts/blob/41c25aa16d182f757c3fed1463c78a81896f65e6/ethereum/contracts/vendor/AddressAliasHelper.sol#L28
-    function _applyL1ToL2Alias(address l1Address) internal pure returns (address l2Address) {
-        unchecked {
-            l2Address = address(uint160(l1Address) + uint160(0x1111000000000000000000000000000000001111));
-        }
-    }
-
     function _requireAdminSender() internal override onlyFromCrossDomainAdmin {}
 }

contracts/chain-adapters/Arbitrum_Forwarder.sol

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity ^0.8.0;
+
+import { ForwarderBase } from "./ForwarderBase.sol";
+import { CrossDomainAddressUtils } from "../libraries/CrossDomainAddressUtils.sol";
+
+/**
+ * @title Arbitrum_Forwarder
+ * @notice This contract expects to receive messages and tokens from the hub pool on L1 and forwards messages to a spoke pool on L3.
+ * It rejects messages which do not originate from a cross domain admin, which is set as the hub pool.
+ * @custom:security-contact bugs@across.to
+ */
+contract Arbitrum_Forwarder is ForwarderBase {
+    // On Arbitrum, L1 msg.senders are derived by aliasing a L1 address.
+    modifier onlyFromCrossDomainAdmin() {
+        require(msg.sender == CrossDomainAddressUtils.applyL1ToL2Alias(crossDomainAdmin), "ONLY_COUNTERPART_GATEWAY");
+        _;
+    }
+
+    /**
+     * @notice Constructs an Arbitrum-specific forwarder contract.
+     * @dev Since this is a proxy contract, we only set immutable variables in the constructor, and leave everything else to be initialized.
+     * This includes variables like the cross domain admin.
+     */
+    constructor() ForwarderBase() {}
+
+    function _requireAdminSender() internal override onlyFromCrossDomainAdmin {}
+}

contracts/chain-adapters/Ovm_Forwarder.sol

@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity ^0.8.0;
+
+import { ForwarderBase } from "./ForwarderBase.sol";
+import { LibOptimismUpgradeable } from "@openzeppelin/contracts-upgradeable/crosschain/optimism/LibOptimismUpgradeable.sol";
+import { Lib_PredeployAddresses } from "@eth-optimism/contracts/libraries/constants/Lib_PredeployAddresses.sol";
+
+/**
+ * @title Ovm_Forwarder
+ * @notice This contract expects to receive messages and tokens from the hub pool on L1 and forwards messages to a spoke pool on L3.
+ * It rejects messages which do not originate from a cross domain admin, which is set as the hub pool.
+ * @dev This forwarder assumes that the cross domain messenger predeploy contract is set to the same contract as the standard OpStack predeploy.
+ * (0x4200000000000000000000000000000000000007). This is because in order to determine the L1 msg.sender of a cross-chain message, we must
+ * query information from that contract.
+ * @custom:security-contact bugs@across.to
+ */
+contract Ovm_Forwarder is ForwarderBase {
+    // Address of the cross domain messenger contract.
+    address public constant MESSENGER = Lib_PredeployAddresses.L2_CROSS_DOMAIN_MESSENGER;
+
+    error NotCrossDomainAdmin();
+
+    /**
+     @notice Constructs an Ovm specific forwarder contract.
+     */
+    constructor() ForwarderBase() {}
+
+    function _requireAdminSender() internal view override {
+        if (LibOptimismUpgradeable.crossChainSender(MESSENGER) != crossDomainAdmin) revert NotCrossDomainAdmin();
+    }
+}

contracts/libraries/CrossDomainAddressUtils.sol

@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity ^0.8.0;
+
+/**
+ * @title AddressUtils
+ * @notice This library contains internal functions for manipulating addresses.
+ */
+library CrossDomainAddressUtils {
+    // L1 addresses are transformed during l1->l2 calls.
+    // This cannot be pulled directly from Arbitrum contracts because their contracts are not 0.8.X compatible and
+    // this operation takes advantage of overflows, whose behavior changed in 0.8.0.
+    function applyL1ToL2Alias(address l1Address) internal pure returns (address l2Address) {
+        unchecked {
+            l2Address = address(uint160(l1Address) + uint160(0x1111000000000000000000000000000000001111));
+        }
+    }
+}