Support Native ETH in v1

contracts/scripts/DeployLocal.sol

@@ -96,15 +96,11 @@ contract DeployLocal is Script {
         // Deploy WETH for testing
         new WETH9();
 
-        // Fund the sovereign account for the BridgeHub parachain. Used to reward relayers
+        // Fund the gateway proxy contract. Used to reward relayers
         // of messages originating from BridgeHub
-        uint256 initialDeposit = vm.envUint("BRIDGE_HUB_INITIAL_DEPOSIT");
+        uint256 initialDeposit = vm.envUint("GATEWAY_PROXY_INITIAL_DEPOSIT");
 
-        address bridgeHubAgent = IGateway(address(gateway)).agentOf(bridgeHubAgentID);
-        address assetHubAgent = IGateway(address(gateway)).agentOf(assetHubAgentID);
-
-        payable(bridgeHubAgent).safeNativeTransfer(initialDeposit);
-        payable(assetHubAgent).safeNativeTransfer(initialDeposit);
+        payable(gateway).safeNativeTransfer(initialDeposit);
 
         // Deploy MockGatewayV2 for testing
         new MockGatewayV2();

contracts/scripts/FundAgent.sol → contracts/scripts/FundGateway.sol

@@ -15,7 +15,7 @@ import {ParaID} from "../src/Types.sol";
 import {SafeNativeTransfer} from "../src/utils/SafeTransfer.sol";
 import {stdJson} from "forge-std/StdJson.sol";
 
-contract FundAgent is Script {
+contract FundGateway is Script {
     using SafeNativeTransfer for address payable;
     using stdJson for string;
 
@@ -26,17 +26,10 @@ contract FundAgent is Script {
         address deployer = vm.rememberKey(privateKey);
         vm.startBroadcast(deployer);
 
-        uint256 initialDeposit = vm.envUint("BRIDGE_HUB_INITIAL_DEPOSIT");
+        uint256 initialDeposit = vm.envUint("GATEWAY_PROXY_INITIAL_DEPOSIT");
         address gatewayAddress = vm.envAddress("GATEWAY_PROXY_CONTRACT");
 
-        bytes32 bridgeHubAgentID = vm.envBytes32("BRIDGE_HUB_AGENT_ID");
-        bytes32 assetHubAgentID = vm.envBytes32("ASSET_HUB_AGENT_ID");
-
-        address bridgeHubAgent = IGateway(gatewayAddress).agentOf(bridgeHubAgentID);
-        address assetHubAgent = IGateway(gatewayAddress).agentOf(assetHubAgentID);
-
-        payable(bridgeHubAgent).safeNativeTransfer(initialDeposit);
-        payable(assetHubAgent).safeNativeTransfer(initialDeposit);
+        payable(gatewayAddress).safeNativeTransfer(initialDeposit);
 
         vm.stopBroadcast();
     }

contracts/src/Assets.sol

@@ -13,6 +13,7 @@ import {CoreStorage} from "./storage/CoreStorage.sol";
 import {SubstrateTypes} from "./SubstrateTypes.sol";
 import {ParaID, MultiAddress, Ticket, Costs} from "./Types.sol";
 import {Address} from "./utils/Address.sol";
+import {SafeNativeTransfer} from "./utils/SafeTransfer.sol";
 import {AgentExecutor} from "./AgentExecutor.sol";
 import {Agent} from "./Agent.sol";
 import {Call} from "./utils/Call.sol";
@@ -21,6 +22,7 @@ import {Token} from "./Token.sol";
 /// @title Library for implementing Ethereum->Polkadot ERC20 transfers.
 library Assets {
     using Address for address;
+    using SafeNativeTransfer for address payable;
     using SafeTokenTransferFrom for IERC20;
 
     /* Errors */
@@ -34,6 +36,7 @@ library Assets {
     error TokenAlreadyRegistered();
     error TokenMintFailed();
     error TokenTransferFailed();
+    error TokenAmountTooLow();
 
     function isTokenRegistered(address token) external view returns (bool) {
         return AssetsStorage.layout().tokenRegistry[token].isRegistered;
@@ -60,7 +63,7 @@ library Assets {
     ) external view returns (Costs memory costs) {
         AssetsStorage.Layout storage $ = AssetsStorage.layout();
         TokenInfo storage info = $.tokenRegistry[token];
-        if (!info.isRegistered) {
+        if (!info.isRegistered && token != address(0)) {
             revert TokenNotRegistered();
         }
 
@@ -110,15 +113,17 @@ library Assets {
 
         TokenInfo storage info = $.tokenRegistry[token];
 
-        if (!info.isRegistered) {
-            revert TokenNotRegistered();
-        }
-
         if (info.foreignID == bytes32(0)) {
+            if (!info.isRegistered && token != address(0)) {
+                revert TokenNotRegistered();
+            }
             return _sendNativeToken(
                 token, sender, destinationChain, destinationAddress, destinationChainFee, maxDestinationChainFee, amount
             );
         } else {
+            if (!info.isRegistered) {
+                revert TokenNotRegistered();
+            }
             return _sendForeignToken(
                 info.foreignID,
                 token,
@@ -144,7 +149,18 @@ library Assets {
         AssetsStorage.Layout storage $ = AssetsStorage.layout();
 
         // Lock the funds into AssetHub's agent contract
-        _transferToAgent($.assetHubAgent, token, sender, amount);
+        if (token != address(0)) {
+            // ERC20
+            _transferToAgent($.assetHubAgent, token, sender, amount);
+            ticket.etherAmount = 0;
+        } else {
+            // Native ETH
+            if (msg.value < amount) {
+                revert TokenAmountTooLow();
+            }
+            payable($.assetHubAgent).safeNativeTransfer(amount);
+            ticket.etherAmount = amount;
+        }
 
         ticket.dest = $.assetHubParaID;
         ticket.costs = _sendTokenCosts(destinationChain, destinationChainFee, maxDestinationChainFee);
@@ -211,6 +227,7 @@ library Assets {
 
         ticket.dest = $.assetHubParaID;
         ticket.costs = _sendTokenCosts(destinationChain, destinationChainFee, maxDestinationChainFee);
+        ticket.etherAmount = 0;
 
         // Construct a message payload
         if (destinationChain == $.assetHubParaID && destinationAddress.isAddress32()) {
@@ -254,14 +271,15 @@ library Assets {
         // It means that registration can be retried.
         // But register a PNA here is not allowed
         TokenInfo storage info = $.tokenRegistry[token];
-        if(info.foreignID != bytes32(0)) {
+        if (info.foreignID != bytes32(0)) {
             revert TokenAlreadyRegistered();
         }
         info.isRegistered = true;
 
         ticket.dest = $.assetHubParaID;
         ticket.costs = _registerTokenCosts();
         ticket.payload = SubstrateTypes.RegisterToken(token, $.assetHubCreateAssetFee);
+        ticket.etherAmount = 0;
 
         emit IGateway.TokenRegistrationSent(token);
     }
@@ -293,7 +311,14 @@ library Assets {
     function transferNativeToken(address executor, address agent, address token, address recipient, uint128 amount)
         external
     {
-        bytes memory call = abi.encodeCall(AgentExecutor.transferToken, (token, recipient, amount));
+        bytes memory call;
+        if (token != address(0)) {
+            // ERC20
+            call = abi.encodeCall(AgentExecutor.transferToken, (token, recipient, amount));
+        } else {
+            // Native ETH
+            call = abi.encodeCall(AgentExecutor.transferNative, (payable(recipient), amount));
+        }
         (bool success,) = Agent(payable(agent)).invoke(executor, call);
         if (!success) {
             revert TokenTransferFailed();

contracts/src/Gateway.sol

@@ -88,7 +88,7 @@ contract Gateway is IGateway, IInitializable, IUpgradable {
     error InvalidProof();
     error InvalidNonce();
     error NotEnoughGas();
-    error FeePaymentToLow();
+    error FeePaymentTooLow();
     error Unauthorized();
     error Disabled();
     error AgentAlreadyCreated();
@@ -99,6 +99,7 @@ contract Gateway is IGateway, IInitializable, IUpgradable {
     error InvalidAgentExecutionPayload();
     error InvalidConstructorParams();
     error TokenNotRegistered();
+    error TokenAmountTooLow();
 
     // Message handlers can only be dispatched by the gateway itself
     modifier onlySelf() {
@@ -240,11 +241,11 @@ contract Gateway is IGateway, IInitializable, IUpgradable {
 
         // Add the reward to the refund amount. If the sum is more than the funds available
         // in the channel agent, then reduce the total amount
-        uint256 amount = Math.min(refund + message.reward, address(channel.agent).balance);
+        uint256 amount = Math.min(refund + message.reward, address(this).balance);
 
-        // Do the payment if there funds available in the agent
+        // Do the payment if there funds available in the gateway
         if (amount > _dustThreshold()) {
-            _transferNativeFromAgent(channel.agent, payable(msg.sender), amount);
+            payable(msg.sender).safeNativeTransfer(amount);
         }
 
         emit IGateway.InboundMessageDispatched(message.channelID, message.nonce, message.id, success);
@@ -530,18 +531,17 @@ contract Gateway is IGateway, IInitializable, IUpgradable {
         uint256 fee = _calculateFee(ticket.costs);
 
         // Ensure the user has enough funds for this message to be accepted
-        if (msg.value < fee) {
-            revert FeePaymentToLow();
+        uint256 totalEther = fee + ticket.etherAmount;
+        if (msg.value < totalEther) {
+            revert FeePaymentTooLow();
         }
 
         channel.outboundNonce = channel.outboundNonce + 1;
 
-        // Deposit total fee into agent's contract
-        payable(channel.agent).safeNativeTransfer(fee);
-
+        // The fee is already collected into the gateway contract
         // Reimburse excess fee payment
-        if (msg.value > fee) {
-            payable(msg.sender).safeNativeTransfer(msg.value - fee);
+        if (msg.value > totalEther) {
+            payable(msg.sender).safeNativeTransfer(msg.value - totalEther);
         }
 
         // Generate a unique ID for this message

contracts/src/GatewayProxy.sol

@@ -37,9 +37,6 @@ contract GatewayProxy is IInitializable {
         }
     }
 
-    // Prevent users from unwittingly sending ether to the gateway, as these funds
-    // would otherwise be lost forever.
-    receive() external payable {
-        revert NativeCurrencyNotAccepted();
-    }
+    // Allow the Gateway proxy to receive ether in order to pay out rewards and refunds
+    receive() external payable {}
 }

contracts/src/Types.sol

@@ -107,6 +107,7 @@ struct Ticket {
     ParaID dest;
     Costs costs;
     bytes payload;
+    uint128 etherAmount;
 }
 
 struct TokenInfo {

contracts/test/Bitfield.t.sol

@@ -16,7 +16,6 @@ contract BitfieldTest is Test {
 
         string memory json = vm.readFile(string.concat(vm.projectRoot(), "/test/data/beefy-validator-set.json"));
         uint32 setSize = uint32(json.readUint(".validatorSetSize"));
-        bytes32 root = json.readBytes32(".validatorRoot");
         uint256[] memory bitSetArray = json.readUintArray(".participants");
 
         uint256[] memory initialBitField = bw.createBitfield(bitSetArray, setSize);