Interface and Contract Changes for Step 1 of Permissionless Generic Relayer Plan

.gitignore

@@ -1,5 +1,4 @@
 .idea
 .vscode
 
-**/pkeys.sh
-**/pkeys_tilt.sh
+**/pkeys.sh

ethereum/contracts/coreRelayer/CoreRelayerGetters.sol

@@ -1,11 +1,10 @@
-// contracts/Getters.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
 
 import "../interfaces/IWormhole.sol";
 import "../interfaces/IRelayProvider.sol";
-import "./CoreRelayerStructs.sol";
+import "../interfaces/IWormholeRelayerInternalStructs.sol";
 
 import "./CoreRelayerState.sol";
 import "../libraries/external/BytesLib.sol";
@@ -53,10 +52,14 @@ contract CoreRelayerGetters is CoreRelayerState {
         return _state.defaultRelayProvider;
     }
 
-    function getForwardInstruction() internal view returns (CoreRelayerStructs.ForwardInstruction memory) {
+    function getForwardInstruction() public view returns (IWormholeRelayerInternalStructs.ForwardInstruction memory) {
         return _state.forwardInstruction;
     }
 
+    function getWormholeRelayerCallerAddress() public view returns (address) {
+        return _state.forwardWrapper;
+    }
+
     function isContractLocked() internal view returns (bool) {
         return _state.contractLock;
     }

ethereum/contracts/coreRelayer/CoreRelayerGovernance.sol

@@ -1,4 +1,3 @@
-// contracts/Relayer.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
@@ -9,7 +8,7 @@ import "../libraries/external/BytesLib.sol";
 
 import "./CoreRelayerGetters.sol";
 import "./CoreRelayerSetters.sol";
-import "./CoreRelayerStructs.sol";
+import "../interfaces/IWormholeRelayerInternalStructs.sol";
 import "./CoreRelayerMessages.sol";
 
 import "../interfaces/IWormhole.sol";

ethereum/contracts/coreRelayer/CoreRelayerImplementation.sol

@@ -1,4 +1,3 @@
-// contracts/Implementation.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;

ethereum/contracts/coreRelayer/CoreRelayerProxy.sol

@@ -1,4 +1,3 @@
-// contracts/Wormhole.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;

ethereum/contracts/coreRelayer/CoreRelayerSetters.sol

@@ -1,11 +1,10 @@
-// contracts/Setters.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
 
 import "./CoreRelayerState.sol";
 import "@openzeppelin/contracts/utils/Context.sol";
-import "./CoreRelayerStructs.sol";
+import "../interfaces/IWormholeRelayerInternalStructs.sol";
 import {IWormhole} from "../interfaces/IWormhole.sol";
 
 contract CoreRelayerSetters is CoreRelayerState, Context {
@@ -43,7 +42,7 @@ contract CoreRelayerSetters is CoreRelayerState, Context {
         _state.registeredCoreRelayerContract[chainId] = relayerAddress;
     }
 
-    function setForwardInstruction(CoreRelayerStructs.ForwardInstruction memory request) internal {
+    function setForwardInstruction(IWormholeRelayerInternalStructs.ForwardInstruction memory request) internal {
         _state.forwardInstruction = request;
     }
 
@@ -59,6 +58,10 @@ contract CoreRelayerSetters is CoreRelayerState, Context {
         _state.targetAddress = targetAddress;
     }
 
+    function setForwardWrapper(address newForwardWrapperAddress) internal {
+        _state.forwardWrapper = newForwardWrapperAddress;
+    }
+
     function setEvmChainId(uint256 evmChainId) internal {
         if (evmChainId != block.chainid) {
             revert InvalidEvmChainId();

ethereum/contracts/coreRelayer/CoreRelayerSetup.sol

@@ -1,9 +1,9 @@
-// contracts/Setup.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
 
 import "./CoreRelayerGovernance.sol";
+import "./ForwardWrapper.sol";
 
 import "@openzeppelin/contracts/proxy/ERC1967/ERC1967Upgrade.sol";
 
@@ -43,6 +43,8 @@ contract CoreRelayerSetup is CoreRelayerSetters, ERC1967Upgrade {
         setGovernanceContract(governanceContract);
         setEvmChainId(evmChainId);
 
+        setForwardWrapper(address(new ForwardWrapper(address(this), wormhole)));
+
         _upgradeTo(implementation);
 
         // call initialize function of the new implementation

ethereum/contracts/coreRelayer/CoreRelayerState.sol

@@ -1,9 +1,8 @@
-// contracts/State.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
 
-import "./CoreRelayerStructs.sol";
+import "../interfaces/IWormholeRelayerInternalStructs.sol";
 
 contract CoreRelayerStorage {
     struct Provider {
@@ -26,7 +25,9 @@ contract CoreRelayerStorage {
         // address of the default relay provider on this chain
         address defaultRelayProvider;
         // Request which will be forwarded from the current delivery.
-        CoreRelayerStructs.ForwardInstruction forwardInstruction;
+        IWormholeRelayerInternalStructs.ForwardInstruction forwardInstruction;
+        // Wrapper contract to facilitate forwards
+        address forwardWrapper;
         // mapping of initialized implementations
         mapping(address => bool) initializedImplementations;
         // mapping of relayer contracts on other chains

ethereum/contracts/coreRelayer/ForwardWrapper.sol

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: Apache 2
+
+pragma solidity ^0.8.0;
+
+import "../interfaces/IWormholeReceiver.sol";
+import "../interfaces/IWormhole.sol";
+import "../interfaces/IRelayProvider.sol";
+import "../interfaces/IForwardInstructionViewer.sol";
+import "../interfaces/IWormholeRelayerInternalStructs.sol";
+import "../interfaces/IForwardWrapper.sol";
+import "../interfaces/IWormholeReceiver.sol";
+import "../interfaces/IRelayProvider.sol";
+
+contract ForwardWrapper {
+    IForwardInstructionViewer forwardInstructionViewer;
+    IWormhole wormhole;
+
+    error RequesterNotCoreRelayer();
+    error ForwardNotSufficientlyFunded(uint256 amountOfFunds, uint256 amountOfFundsNeeded);
+
+    constructor(address _wormholeRelayer, address _wormhole) {
+        forwardInstructionViewer = IForwardInstructionViewer(_wormholeRelayer);
+        wormhole = IWormhole(_wormhole);
+    }
+
+    function executeInstruction(
+        IWormholeRelayerInternalStructs.DeliveryInstruction memory instruction,
+        IWormholeReceiver.DeliveryData memory data,
+        bytes[] memory signedVaas
+    ) public payable returns (bool callToTargetContractSucceeded, uint256 transactionFeeRefundAmount) {
+        if (msg.sender != address(forwardInstructionViewer)) {
+            revert RequesterNotCoreRelayer();
+        }
+
+        uint256 preGas = gasleft();
+
+        // Calls the 'receiveWormholeMessages' endpoint on the contract 'instruction.targetAddress'
+        // (with the gas limit and value specified in instruction, and 'encodedVMs' as the input)
+        (callToTargetContractSucceeded,) = forwardInstructionViewer.fromWormholeFormat(instruction.targetAddress).call{
+            gas: instruction.executionParameters.gasLimit,
+            value: instruction.receiverValueTarget
+        }(abi.encodeCall(IWormholeReceiver.receiveWormholeMessages, ((data), signedVaas)));
+
+        uint256 postGas = gasleft();
+
+        // Calculate the amount of gas used in the call (upperbounding at the gas limit, which shouldn't have been exceeded)
+        uint256 gasUsed = (preGas - postGas) > instruction.executionParameters.gasLimit
+            ? instruction.executionParameters.gasLimit
+            : (preGas - postGas);
+
+        // Calculate the amount of maxTransactionFee to refund (multiply the maximum refund by the fraction of gas unused)
+        transactionFeeRefundAmount = (instruction.executionParameters.gasLimit - gasUsed)
+            * instruction.maximumRefundTarget / instruction.executionParameters.gasLimit;
+
+        IWormholeRelayerInternalStructs.ForwardInstruction memory forwardInstruction =
+            forwardInstructionViewer.getForwardInstruction();
+
+        if (forwardInstruction.isValid) {
+            uint256 feeForForward = transactionFeeRefundAmount + forwardInstruction.msgValue;
+            if (feeForForward < forwardInstruction.totalFee) {
+                revert ForwardNotSufficientlyFunded(feeForForward, forwardInstruction.totalFee);
+            }
+        }
+
+        if (!callToTargetContractSucceeded) {
+            msg.sender.call{value: msg.value}("");
+        }
+    }
+
+    function safeRelayProviderSupportsChain(IRelayProvider relayProvider, uint16 chainId) view external returns (bool isSupported){
+        return relayProvider.isChainSupported(chainId);
+    }
+}

ethereum/contracts/example_integrations/xMint/Hub.sol

@@ -48,7 +48,11 @@ contract XmintHub is ERC20, IWormholeReceiver {
     }
 
     //This is the function which receives all messages from the remote contracts.
-    function receiveWormholeMessages(bytes[] memory vaas, bytes[] memory additionalData) public payable override {
+    function receiveWormholeMessages(IWormholeReceiver.DeliveryData memory deliveryData, bytes[] memory vaas)
+        public
+        payable
+        override
+    {
         //The first message should be from the token bridge, so attempt to redeem it.
         ITokenBridge.TransferWithPayload memory transferResult =
             token_bridge.parseTransferWithPayload(token_bridge.completeTransferWithPayload(vaas[0]));
@@ -90,18 +94,21 @@ contract XmintHub is ERC20, IWormholeReceiver {
             core_relayer.quoteGas(targetChain, SAFE_DELIVERY_GAS_CAPTURE, core_relayer.getDefaultRelayProvider());
         uint256 receiverValue = 0;
 
+        bytes memory emptyArray;
         IWormholeRelayer.Send memory request = IWormholeRelayer.Send({
             targetChain: targetChain,
             targetAddress: trustedContracts[targetChain],
+            refundChain: targetChain,
             refundAddress: intendedRecipient, // All remaining funds will be returned to the user now
             maxTransactionFee: maxTransactionFee,
             receiverValue: receiverValue, // not needed in this case.
+            payload: emptyArray,
             relayParameters: core_relayer.getDefaultRelayParams() //no overrides
         });
 
-        core_relayer.send{value: maxTransactionFee + receiverValue}(
-            request, nonce, core_relayer.getDefaultRelayProvider()
-        );
+        // core_relayer.send{value: maxTransactionFee + receiverValue}(
+        //    request, nonce, core_relayer.getDefaultRelayProvider()
+        //);
     }
 
     //This function calculates how many tokens should be minted to the end user based on how much

ethereum/contracts/example_integrations/xMint/Spoke.sol

@@ -66,7 +66,11 @@ contract XmintSpoke is IWormholeReceiver {
     }
 
     //This function receives messages back from the Hub contract and distributes the tokens to the user.
-    function receiveWormholeMessages(bytes[] memory vaas, bytes[] memory additionalData) public payable override {
+    function receiveWormholeMessages(IWormholeReceiver.DeliveryData memory deliveryData, bytes[] memory vaas)
+        public
+        payable
+        override
+    {
         //Complete the token bridge transfer
         ITokenBridge.TransferWithPayload memory transferResult =
             token_bridge.parseTransferWithPayload(token_bridge.completeTransferWithPayload(vaas[0]));
@@ -88,18 +92,21 @@ contract XmintSpoke is IWormholeReceiver {
             core_relayer.quoteGas(hub_contract_chain, SAFE_DELIVERY_GAS_CAPTURE, core_relayer.getDefaultRelayProvider());
         uint256 receiverValue = 0;
 
+        bytes memory emptyArray;
         IWormholeRelayer.Send memory request = IWormholeRelayer.Send({
             targetChain: hub_contract_chain,
             targetAddress: hub_contract_address,
+            refundChain: hub_contract_chain,
             refundAddress: hub_contract_address, // This will be ignored on the target chain because the intent is to perform a forward
             maxTransactionFee: maxTransactionFee,
             receiverValue: receiverValue, // not needed in this case.
+            payload: emptyArray,
             relayParameters: core_relayer.getDefaultRelayParams() //no overrides
         });
 
-        core_relayer.send{value: maxTransactionFee + receiverValue}(
-            request, nonce, core_relayer.getDefaultRelayProvider()
-        );
+        //core_relayer.send{value: maxTransactionFee + receiverValue}(
+        //     request, nonce, core_relayer.getDefaultRelayProvider()
+        //);
     }
 
     function bytesToBytes32(bytes memory b, uint256 offset) private pure returns (bytes32) {