feat(node): support l2 plus value transfer

contracts/contracts/errors/IPCErrors.sol

@@ -94,7 +94,8 @@ enum InvalidXnetMessageReason {
     Value,
     Kind,
     CannotSendToItself,
-    CommonParentNotExist
+    CommonParentNotExist,
+    IncompatibleSupplySource
 }
 
 string constant ERR_PERMISSIONED_AND_BOOTSTRAPPED = "Method not allowed if permissioned is enabled and subnet bootstrapped";

contracts/contracts/gateway/GatewayMessengerFacet.sol

@@ -4,14 +4,15 @@ pragma solidity ^0.8.23;
 import {GatewayActorModifiers} from "../lib/LibGatewayActorStorage.sol";
 import {IpcEnvelope, CallMsg, IpcMsgKind} from "../structs/CrossNet.sol";
 import {IPCMsgType} from "../enums/IPCMsgType.sol";
-import {Subnet, SubnetID, AssetKind, IPCAddress} from "../structs/Subnet.sol";
+import {Subnet, SubnetID, AssetKind, IPCAddress, Asset} from "../structs/Subnet.sol";
 import {InvalidXnetMessage, InvalidXnetMessageReason, CannotSendCrossMsgToItself, MethodNotAllowed, UnroutableMessage} from "../errors/IPCErrors.sol";
 import {SubnetIDHelper} from "../lib/SubnetIDHelper.sol";
 import {LibGateway, CrossMessageValidationOutcome} from "../lib/LibGateway.sol";
 import {FilAddress} from "fevmate/contracts/utils/FilAddress.sol";
 import {AssetHelper} from "../lib/AssetHelper.sol";
 import {CrossMsgHelper} from "../lib/CrossMsgHelper.sol";
 import {FvmAddressHelper} from "../lib/FvmAddressHelper.sol";
+import {ISubnetActor} from "../interfaces/ISubnetActor.sol";
 
 import {EnumerableSet} from "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
 
@@ -23,6 +24,7 @@ contract GatewayMessengerFacet is GatewayActorModifiers {
     using SubnetIDHelper for SubnetID;
     using EnumerableSet for EnumerableSet.Bytes32Set;
     using CrossMsgHelper for IpcEnvelope;
+    using AssetHelper for Asset;
 
     /**
      * @dev Sends a general-purpose cross-message from the local subnet to the destination subnet.
@@ -47,10 +49,6 @@ contract GatewayMessengerFacet is GatewayActorModifiers {
             revert InvalidXnetMessage(InvalidXnetMessageReason.Sender);
         }
 
-        if (envelope.kind != IpcMsgKind.Call) {
-            revert InvalidXnetMessage(InvalidXnetMessageReason.Kind);
-        }
-
         // Will revert if the message won't deserialize into a CallMsg.
         abi.decode(envelope.message, (CallMsg));
 
@@ -63,7 +61,7 @@ contract GatewayMessengerFacet is GatewayActorModifiers {
             nonce: 0 // nonce will be updated by LibGateway.commitValidatedCrossMessage
         });
 
-        CrossMessageValidationOutcome outcome = committed.validateCrossMessage();
+        (CrossMessageValidationOutcome outcome, IPCMsgType applyType) = committed.validateCrossMessage();
 
         if (outcome != CrossMessageValidationOutcome.Valid) {
             if (outcome == CrossMessageValidationOutcome.InvalidDstSubnet) {
@@ -75,6 +73,12 @@ contract GatewayMessengerFacet is GatewayActorModifiers {
             }
         }
 
+        if (applyType == IPCMsgType.TopDown) {
+            (, SubnetID memory nextHop) = committed.to.subnetId.down(s.networkName);
+            // lock funds on the current subnet gateway for the next hop
+            ISubnetActor(nextHop.getActor()).supplySource().lock(envelope.value);
+        }
+
         // Commit xnet message for dispatch.
         bool shouldBurn = LibGateway.commitValidatedCrossMessage(committed);
 

contracts/contracts/interfaces/ISubnetActor.sol

@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity ^0.8.23;
+
+import {Asset} from "../structs/Subnet.sol";
+
+/// @title Subnet actor interface
+interface ISubnetActor {
+    function supplySource() external view returns (Asset memory);
+}

contracts/contracts/lib/AssetHelper.sol

@@ -6,7 +6,7 @@ import {Asset, AssetKind} from "../structs/Subnet.sol";
 import {EMPTY_BYTES} from "../constants/Constants.sol";
 import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
-import {SubnetActorGetterFacet} from "../subnet/SubnetActorGetterFacet.sol";
+import {ISubnetActor} from "../interfaces/ISubnetActor.sol";
 
 /// @notice Helpers to deal with a supply source.
 library AssetHelper {
@@ -16,7 +16,7 @@ library AssetHelper {
     ///         and checks if its supply kind matches the provided one.
     ///         It reverts if the address does not correspond to a subnet actor.
     function hasSupplyOfKind(address subnetActor, AssetKind compare) internal view returns (bool) {
-        return SubnetActorGetterFacet(subnetActor).supplySource().kind == compare;
+        return ISubnetActor(subnetActor).supplySource().kind == compare;
     }
 
     /// @notice Checks that a given supply strategy is correctly formed and its preconditions are met.
@@ -37,6 +37,10 @@ library AssetHelper {
         require(asset.kind == kind, "Unexpected asset");
     }
 
+    function equals(Asset memory asset, Asset memory asset2) internal pure returns (bool) {
+        return asset.tokenAddress == asset2.tokenAddress && asset.kind == asset2.kind;
+    }
+
     /// @notice Locks the specified amount from msg.sender into custody.
     ///         Reverts with NoBalanceIncrease if the token balance does not increase.
     ///         May return more than requested for inflationary tokens due to balance rise.
@@ -236,4 +240,7 @@ library AssetHelper {
         return Asset({kind: AssetKind.Native, tokenAddress: address(0)});
     }
 
+    function erc20(address token) internal pure returns (Asset memory) {
+        return Asset({kind: AssetKind.ERC20, tokenAddress: token});
+    }
 }

contracts/contracts/lib/CrossMsgHelper.sol

@@ -72,8 +72,7 @@ library CrossMsgHelper {
         uint256 value = crossMsg.value;
         // if the message was executed successfully, the value stayed
         // in the subnet and there's no need to return it.
-        // or if the message is a call, the value is always 0 because transfers for calls are not allowed
-        if (outcome == OutcomeType.Ok || crossMsg.kind == IpcMsgKind.Call) {
+        if (outcome == OutcomeType.Ok) {
             value = 0;
         }
         return
@@ -182,20 +181,19 @@ library CrossMsgHelper {
         }
 
         address recipient = crossMsg.to.rawAddress.extractEvmAddress().normalize();
-        if (crossMsg.kind == IpcMsgKind.Transfer) {
+        // If the cross msg kind is Result, create result message should have handled the value correctly.
+        // If the execution is ok, value should be 0, else one should perform refund.
+        if (crossMsg.kind == IpcMsgKind.Transfer || crossMsg.kind == IpcMsgKind.Result) {
             return supplySource.transferFunds({recipient: payable(recipient), value: crossMsg.value});
-        } else if (crossMsg.kind == IpcMsgKind.Call || crossMsg.kind == IpcMsgKind.Result) {
-            // transferring funds is not allowed for Call messages
-            uint256 value = crossMsg.kind == IpcMsgKind.Call ? 0 : crossMsg.value;
-
+        } else if (crossMsg.kind == IpcMsgKind.Call) {
             // send the envelope directly to the entrypoint
             // use supplySource so the tokens in the message are handled successfully
             // and by the right supply source
             return
                 supplySource.performCall(
                     payable(recipient),
                     abi.encodeCall(IIpcHandler.handleIpcMessage, (crossMsg)),
-                    value
+                    crossMsg.value
                 );
         }
         return (false, EMPTY_BYTES);
@@ -224,7 +222,7 @@ library CrossMsgHelper {
         return true;
     }
 
-    function validateCrossMessage(IpcEnvelope memory crossMsg) internal view returns (CrossMessageValidationOutcome)  {
-        return LibGateway.validateCrossMessage(crossMsg);
+    function validateCrossMessage(IpcEnvelope memory crossMsg) internal view returns (CrossMessageValidationOutcome, IPCMsgType)  {
+        return LibGateway.checkCrossMessage(crossMsg);
     }
 }

contracts/contracts/lib/LibGateway.sol

@@ -13,14 +13,16 @@ import {CrossMsgHelper} from "../lib/CrossMsgHelper.sol";
 import {FilAddress} from "fevmate/contracts/utils/FilAddress.sol";
 import {SubnetIDHelper} from "../lib/SubnetIDHelper.sol";
 import {AssetHelper} from "../lib/AssetHelper.sol";
+import {ISubnetActor} from "../interfaces/ISubnetActor.sol";
 import {EnumerableSet} from "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
 
 // Validation outcomes for cross messages
 enum CrossMessageValidationOutcome {
     Valid,
     InvalidDstSubnet,
     CannotSendToItself,
-    CommonParentNotExist
+    CommonParentNotExist,
+    IncompatibleSupplySource
 }
 
 library LibGateway {
@@ -251,9 +253,7 @@ library LibGateway {
 
         crossMessage.nonce = topDownNonce;
         subnet.topDownNonce = topDownNonce + 1;
-        if (crossMessage.kind != IpcMsgKind.Call) {
-            subnet.circSupply += crossMessage.value;
-        }
+        subnet.circSupply += crossMessage.value;
 
         emit NewTopDownMessage({subnet: subnet.id.getAddress(), message: crossMessage, id: crossMessage.toDeterministicHash()});
     }
@@ -464,7 +464,7 @@ library LibGateway {
             emit MessageStoredInPostbox({id: crossMsg.toDeterministicHash()});
             return;
         }
-    
+
         // execute the message and get the receipt.
         (bool success, bytes memory ret) = executeCrossMsg(crossMsg, supplySource);
         if (success) {
@@ -567,54 +567,120 @@ library LibGateway {
         }
     }
 
+    /// Checks if the incoming and outgoing subnet supply sources can be mapped.
+    /// Caller should make sure the incoming/outgoing subnets and current subnet are immediate parent/child subnets.
+    function checkSubnetsSupplyCompatible(
+        bool isLCA,
+        IPCMsgType applyType,
+        SubnetID memory incoming,
+        SubnetID memory outgoing,
+        SubnetID memory current
+    ) internal view returns(bool) {
+        if (isLCA) {
+            // now, it's pivoting @ LCA (i.e. upwards => downwards)
+            // if incoming bottom up subnet and outgoing target subnet have the same 
+            // asset, we will allow it. This is because if they are using the 
+            // same asset, then the asset can be mapped in both subnets.
+
+            (, SubnetID memory incDown) = incoming.down(current);
+            (, SubnetID memory outDown) = outgoing.down(current);
+
+            Asset memory incAsset = ISubnetActor(incDown.getActor()).supplySource();
+            Asset memory outAsset = ISubnetActor(outDown.getActor()).supplySource();
+
+            return incAsset.equals(outAsset);
+        }
+
+        if (applyType == IPCMsgType.BottomUp) {
+            // The child subnet has supply source native, this is the same as 
+            // the current subnet's native source, the mapping makes sense, propagate up.
+            (, SubnetID memory incDown) = incoming.down(current);
+            return incDown.getActor().hasSupplyOfKind(AssetKind.Native);
+        }
+
+        // Topdown handling
+
+        // The incoming subnet's supply source will be mapped to native coin in the 
+        // next child subnet. If the down subnet has native, then the mapping makes 
+        // sense.
+        (, SubnetID memory down) = outgoing.down(current);
+        return down.getActor().hasSupplyOfKind(AssetKind.Native);
+    }
+
     /// @notice Validates a cross message before committing it.
     function validateCrossMessage(IpcEnvelope memory envelope) internal view returns (CrossMessageValidationOutcome) {
-        GatewayActorStorage storage s = LibGatewayActorStorage.appStorage();
-        SubnetID memory toSubnetId = envelope.to.subnetId;
+        (CrossMessageValidationOutcome outcome, ) = checkCrossMessage(envelope);
+        return outcome;
+    }
 
+    /// @notice Validates a cross message and returns the applyType if the message is valid
+    function checkCrossMessage(IpcEnvelope memory envelope) internal view returns (CrossMessageValidationOutcome, IPCMsgType applyType) {
+        SubnetID memory toSubnetId = envelope.to.subnetId;
         if (toSubnetId.isEmpty()) {
-            return CrossMessageValidationOutcome.InvalidDstSubnet;
+            return (CrossMessageValidationOutcome.InvalidDstSubnet, applyType);
         }
 
+        GatewayActorStorage storage s = LibGatewayActorStorage.appStorage();
+        SubnetID memory currentNetwork = s.networkName;
+
         // We cannot send a cross message to the same subnet.
-        if (toSubnetId.equals(s.networkName)) {
-            return CrossMessageValidationOutcome.CannotSendToItself;
+        if (toSubnetId.equals(currentNetwork)) {
+            return (CrossMessageValidationOutcome.CannotSendToItself, applyType);
         }
 
         // Lowest common ancestor subnet
-        bool isLCA = toSubnetId.commonParent(envelope.from.subnetId).equals(s.networkName);
-        IPCMsgType applyType = envelope.applyType(s.networkName);
-        
+        bool isLCA = toSubnetId.commonParent(envelope.from.subnetId).equals(currentNetwork);
+        applyType = envelope.applyType(currentNetwork);
+
         // If the directionality is top-down, or if we're inverting the direction
         // else we need to check if the common parent exists.
         if (applyType == IPCMsgType.TopDown || isLCA) {
-            (bool foundChildSubnetId, SubnetID memory childSubnetId) = toSubnetId.down(s.networkName);
+            (bool foundChildSubnetId, SubnetID memory childSubnetId) = toSubnetId.down(currentNetwork);
             if (!foundChildSubnetId) {
-                return CrossMessageValidationOutcome.InvalidDstSubnet;
+                return (CrossMessageValidationOutcome.InvalidDstSubnet, applyType);
             }
 
             (bool foundSubnet,) = LibGateway.getSubnet(childSubnetId);
             if (!foundSubnet) {
-                return CrossMessageValidationOutcome.InvalidDstSubnet;
+                return (CrossMessageValidationOutcome.InvalidDstSubnet, applyType);
             }
         } else {
-            SubnetID memory commonParent = toSubnetId.commonParent(s.networkName);
+            SubnetID memory commonParent = toSubnetId.commonParent(currentNetwork);
             if (commonParent.isEmpty()) {
-                return CrossMessageValidationOutcome.CommonParentNotExist;
+                return (CrossMessageValidationOutcome.CommonParentNotExist, applyType);
             }
         }
 
-        return CrossMessageValidationOutcome.Valid;
+        // starting/ending subnet, no need check supply sources
+        if (envelope.from.subnetId.equals(currentNetwork) || envelope.to.subnetId.equals(currentNetwork)) {
+            return (CrossMessageValidationOutcome.Valid, applyType);
+        }
+
+        bool supplySourcesCompatible = checkSubnetsSupplyCompatible({
+            isLCA: isLCA,
+            applyType: applyType, 
+            incoming: envelope.from.subnetId,
+            outgoing: envelope.to.subnetId,
+            current: currentNetwork
+        });
+
+        if (!supplySourcesCompatible) {
+            return (CrossMessageValidationOutcome.IncompatibleSupplySource, applyType);
+        }
+
+        return (CrossMessageValidationOutcome.Valid, applyType);
     }
 
-     // Function to map CrossMessageValidationOutcome to InvalidXnetMessageReason
+    // Function to map CrossMessageValidationOutcome to InvalidXnetMessageReason
     function validationOutcomeToInvalidXnetMsgReason(CrossMessageValidationOutcome outcome) internal pure returns (InvalidXnetMessageReason) {
         if (outcome == CrossMessageValidationOutcome.InvalidDstSubnet) {
             return InvalidXnetMessageReason.DstSubnet;
         } else if (outcome == CrossMessageValidationOutcome.CannotSendToItself) {
             return InvalidXnetMessageReason.CannotSendToItself;
         } else if (outcome == CrossMessageValidationOutcome.CommonParentNotExist) {
             return InvalidXnetMessageReason.CommonParentNotExist;
+        } else if (outcome == CrossMessageValidationOutcome.IncompatibleSupplySource) {
+            return InvalidXnetMessageReason.IncompatibleSupplySource;
         }
 
         revert("Unhandled validation outcome");
@@ -627,10 +693,11 @@ library LibGateway {
         GatewayActorStorage storage s = LibGatewayActorStorage.appStorage();
 
         uint256 keysLength = s.postboxKeys.length();
-        bytes32[] memory ids = new bytes32[](keysLength);
+
+        bytes32[] memory values = s.postboxKeys.values();
+
         for (uint256 i = 0; i < keysLength; ) {
-            bytes32 msgCid = s.postboxKeys.at(i);
-            ids[i] = msgCid;
+            bytes32 msgCid = values[i];
             LibGateway.propagatePostboxMessage(msgCid);
 
             unchecked {

contracts/test/integration/GatewayDiamondToken.t.sol

@@ -232,7 +232,7 @@ contract GatewayDiamondTokenTest is Test, IntegrationTestBase {
         vm.prank(address(saDiamond));
         vm.expectCall(recipient, abi.encodeCall(IIpcHandler.handleIpcMessage, (msgs[0])), 1);
         gatewayDiamond.checkpointer().commitCheckpoint(batch);
-        assertEq(token.balanceOf(recipient), 0);
+        assertEq(token.balanceOf(recipient), 8);
     }
 
     function test_propagation() public {