feat: support l2 plus

contracts/contracts/GatewayDiamond.sol

@@ -16,9 +16,9 @@ import {BATCH_PERIOD, MAX_MSGS_PER_BATCH} from "./structs/CrossNet.sol";
 
 error FunctionNotFound(bytes4 _functionSelector);
 
-bool constant FEATURE_MULTILEVEL_CROSSMSG = false;
+bool constant FEATURE_MULTILEVEL_CROSSMSG = true;
 bool constant FEATURE_GENERAL_PUPRPOSE_CROSSMSG = true;
-uint8 constant FEATURE_SUBNET_DEPTH = 2;
+uint8 constant FEATURE_SUBNET_DEPTH = 10;
 
 contract GatewayDiamond {
     GatewayActorStorage internal s;

contracts/contracts/errors/IPCErrors.sol

@@ -80,6 +80,7 @@ error InvalidFederationPayload();
 error DuplicatedGenesisValidator();
 error NotEnoughGenesisValidators();
 error ValidatorPowerChangeDenied();
+error UnroutableMessage(string reason);
 
 enum InvalidXnetMessageReason {
     Sender,

contracts/contracts/gateway/GatewayManagerFacet.sol

@@ -141,7 +141,7 @@ contract GatewayManagerFacet is GatewayActorModifiers, ReentrancyGuard {
             revert InvalidXnetMessage(InvalidXnetMessageReason.Value);
         }
         // slither-disable-next-line unused-return
-        (bool registered, ) = LibGateway.getSubnet(subnetId);
+        (bool registered, Subnet storage subnet) = LibGateway.getSubnet(subnetId);
         if (!registered) {
             revert NotRegisteredSubnet();
         }
@@ -158,7 +158,7 @@ contract GatewayManagerFacet is GatewayActorModifiers, ReentrancyGuard {
         });
 
         // commit top-down message.
-        LibGateway.commitTopDownMsg(crossMsg);
+        LibGateway.commitTopDownMsg(subnet, crossMsg);
     }
 
     /// @notice Sends funds to a specified subnet receiver using ERC20 tokens.
@@ -174,7 +174,7 @@ contract GatewayManagerFacet is GatewayActorModifiers, ReentrancyGuard {
             revert InvalidXnetMessage(InvalidXnetMessageReason.Value);
         }
         // slither-disable-next-line unused-return
-        (bool registered, ) = LibGateway.getSubnet(subnetId);
+        (bool registered, Subnet storage subnet) = LibGateway.getSubnet(subnetId);
         if (!registered) {
             revert NotRegisteredSubnet();
         }
@@ -199,7 +199,7 @@ contract GatewayManagerFacet is GatewayActorModifiers, ReentrancyGuard {
         });
 
         // Commit top-down message.
-        LibGateway.commitTopDownMsg(crossMsg);
+        LibGateway.commitTopDownMsg(subnet, crossMsg);
     }
 
     /// @notice release() burns the received value locally in subnet and commits a bottom-up message to release the assets in the parent.

contracts/contracts/gateway/GatewayMessengerFacet.sol

@@ -4,21 +4,25 @@ 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 {SubnetID, AssetKind, IPCAddress} from "../structs/Subnet.sol";
-import {InvalidXnetMessage, InvalidXnetMessageReason, CannotSendCrossMsgToItself, MethodNotAllowed} from "../errors/IPCErrors.sol";
+import {Subnet, SubnetID, AssetKind, IPCAddress} from "../structs/Subnet.sol";
+import {InvalidXnetMessage, InvalidXnetMessageReason, CannotSendCrossMsgToItself, MethodNotAllowed, UnroutableMessage} from "../errors/IPCErrors.sol";
 import {SubnetIDHelper} from "../lib/SubnetIDHelper.sol";
-import {LibGateway} from "../lib/LibGateway.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 {EnumerableSet} from "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
+
 string constant ERR_GENERAL_CROSS_MSG_DISABLED = "Support for general-purpose cross-net messages is disabled";
 string constant ERR_MULTILEVEL_CROSS_MSG_DISABLED = "Support for multi-level cross-net messages is disabled";
 
 contract GatewayMessengerFacet is GatewayActorModifiers {
     using FilAddress for address payable;
     using SubnetIDHelper for SubnetID;
+    using EnumerableSet for EnumerableSet.Bytes32Set;
+    using CrossMsgHelper for IpcEnvelope;
 
     /**
      * @dev Sends a general-purpose cross-message from the local subnet to the destination subnet.
@@ -31,7 +35,7 @@ contract GatewayMessengerFacet is GatewayActorModifiers {
      * @return committed envelope.
      */
     function sendContractXnetMessage(
-        IpcEnvelope calldata envelope
+        IpcEnvelope memory envelope
     ) external payable returns (IpcEnvelope memory committed) {
         if (!s.generalPurposeCrossMsg) {
             revert MethodNotAllowed(ERR_GENERAL_CROSS_MSG_DISABLED);
@@ -62,8 +66,20 @@ contract GatewayMessengerFacet is GatewayActorModifiers {
             nonce: 0 // nonce will be updated by LibGateway.commitCrossMessage
         });
 
+        CrossMessageValidationOutcome outcome = committed.validateCrossMessage();
+
+        if (outcome != CrossMessageValidationOutcome.Valid) {
+            if (outcome == CrossMessageValidationOutcome.InvalidDstSubnet) {
+                revert InvalidXnetMessage(InvalidXnetMessageReason.DstSubnet);
+            } else if (outcome == CrossMessageValidationOutcome.CannotSendToItself) {
+                revert CannotSendCrossMsgToItself();
+            } else if (outcome == CrossMessageValidationOutcome.CommonParentNotExist) {
+                revert UnroutableMessage("no common parent");
+            }
+        }
+
         // Commit xnet message for dispatch.
-        bool shouldBurn = LibGateway.commitCrossMessage(committed);
+        bool shouldBurn = LibGateway.commitValidatedCrossMessage(committed);
 
         // Apply side effects, such as burning funds.
         LibGateway.crossMsgSideEffects({v: committed.value, shouldBurn: shouldBurn});
@@ -75,23 +91,9 @@ contract GatewayMessengerFacet is GatewayActorModifiers {
     }
 
     /**
-     * @dev propagates the populated cross net message for the given cid
-     * @param msgCid - the cid of the cross-net message
+     * @dev Propagates all the populated cross-net messages from the postbox.
      */
-    function propagate(bytes32 msgCid) external payable {
-        if (!s.multiLevelCrossMsg) {
-            revert MethodNotAllowed(ERR_MULTILEVEL_CROSS_MSG_DISABLED);
-        }
-
-        IpcEnvelope storage crossMsg = s.postbox[msgCid];
-
-        bool shouldBurn = LibGateway.commitCrossMessage(crossMsg);
-        // We must delete the message first to prevent potential re-entrancies,
-        // and as the message is deleted and we don't have a reference to the object
-        // anymore, we need to pull the data from the message to trigger the side-effects.
-        uint256 v = crossMsg.value;
-        delete s.postbox[msgCid];
-
-        LibGateway.crossMsgSideEffects({v: v, shouldBurn: shouldBurn});
+    function propagateAll() external payable {
+        LibGateway.propagateAllPostboxMessages();
     }
 }

contracts/contracts/gateway/router/CheckpointingFacet.sol

@@ -21,6 +21,9 @@ contract CheckpointingFacet is GatewayActorModifiers {
     using SubnetIDHelper for SubnetID;
     using CrossMsgHelper for IpcEnvelope;
 
+    /// @dev Emitted when a checkpoint is committed to gateway.
+    event CheckpointCommitted(address indexed subnet, uint256 subnetHeight);
+
     /// @notice submit a verified checkpoint in the gateway to trigger side-effects.
     /// @dev this method is called by the corresponding subnet actor.
     ///     Called from a subnet actor if the checkpoint is cryptographically valid.
@@ -41,6 +44,8 @@ contract CheckpointingFacet is GatewayActorModifiers {
         LibGateway.checkMsgLength(checkpoint.msgs);
 
         execBottomUpMsgs(checkpoint.msgs, subnet);
+
+        emit CheckpointCommitted({subnet: checkpoint.subnetID.getAddress(), subnetHeight: checkpoint.blockHeight});
     }
 
     /// @notice creates a new bottom-up checkpoint

contracts/contracts/gateway/router/XnetMessagingFacet.sol

@@ -27,6 +27,7 @@ contract XnetMessagingFacet is GatewayActorModifiers {
     /// @dev It requires the caller to be the system actor.
     /// @param crossMsgs The array of cross-network messages to be applied.
     function applyCrossMessages(IpcEnvelope[] calldata crossMsgs) external systemActorOnly {
-        LibGateway.applyMessages(s.networkName.getParentSubnet(), crossMsgs);
+        LibGateway.applyTopDownMessages(s.networkName.getParentSubnet(), crossMsgs);
+        LibGateway.propagateAllPostboxMessages();
     }
 }

contracts/contracts/interfaces/IGateway.sol

@@ -61,8 +61,8 @@ interface IGateway {
         IpcEnvelope calldata envelope
     ) external payable returns (IpcEnvelope memory committed);
 
-    /// @notice Propagates the stored postbox item for the given cid
-    function propagate(bytes32 msgCid) external payable;
+    /// @notice Propagates all the stored messages to destination subnet
+    function propagateAll() external payable;
 
     /// @notice commit the ipc parent finality into storage
     function commitParentFinality(ParentFinality calldata finality) external;

contracts/contracts/lib/AssetHelper.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.23;
 
-import {NotEnoughBalance} from "../errors/IPCErrors.sol";
+import {NotEnoughBalance, InvalidSubnetActor} from "../errors/IPCErrors.sol";
 import {Asset, AssetKind} from "../structs/Subnet.sol";
 import {EMPTY_BYTES} from "../constants/Constants.sol";
 import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
@@ -145,6 +145,15 @@ library AssetHelper {
         return (success, ret);
     }
 
+    /// @notice Checks if the given address is a contract.
+    function isContract(address account) internal view returns (bool) {
+        uint256 size;
+        assembly {
+            size := extcodesize(account)
+        }
+        return size > 0;
+    }
+
     /// @dev Adaptation from implementation `openzeppelin-contracts/utils/Address.sol`
     /// that doesn't revert immediately in case of failure and merely notifies of the outcome.
     function functionCallWithValue(
@@ -156,6 +165,10 @@ library AssetHelper {
             revert NotEnoughBalance();
         }
 
+        if (!isContract(target)) {
+            revert InvalidSubnetActor();
+        }
+
         return target.call{value: value}(data);
     }
 
@@ -196,6 +209,15 @@ library AssetHelper {
         }
     }
 
+    // @notice Gets the balance of the account.
+    function balanceOf(Asset memory asset, address holder) internal view returns (uint256 ret) {
+        if (asset.kind == AssetKind.Native) {
+            ret = holder.balance;
+        } else if (asset.kind == AssetKind.ERC20) {
+            ret = IERC20(asset.tokenAddress).balanceOf(holder);
+        }
+    }
+
     // @notice Makes the asset available for spending by the given spender, without actually sending it.
     // @return msgValue The amount of msg.value that needs to be sent along with the subsequent call that will _actually_ spend that asset.
     //                  Will be 0 if the asset is a token, since no native coins are to be sent.

contracts/contracts/lib/CrossMsgHelper.sol

@@ -7,6 +7,7 @@ import {IPCMsgType} from "../enums/IPCMsgType.sol";
 import {SubnetID, IPCAddress} from "../structs/Subnet.sol";
 import {SubnetIDHelper} from "../lib/SubnetIDHelper.sol";
 import {FvmAddressHelper} from "../lib/FvmAddressHelper.sol";
+import {LibGateway, CrossMessageValidationOutcome} from "../lib/LibGateway.sol";
 import {FvmAddress} from "../structs/FvmAddress.sol";
 import {FilAddress} from "fevmate/contracts/utils/FilAddress.sol";
 import {Address} from "@openzeppelin/contracts/utils/Address.sol";
@@ -67,6 +68,7 @@ library CrossMsgHelper {
         bytes memory ret
     ) public pure returns (IpcEnvelope memory) {
         ResultMsg memory message = ResultMsg({id: toHash(crossMsg), outcome: outcome, ret: ret});
+
         uint256 value = crossMsg.value;
         if (outcome == OutcomeType.Ok) {
             // if the message was executed successfully, the value stayed
@@ -84,6 +86,7 @@ library CrossMsgHelper {
             });
     }
 
+    // creates transfer message from the child subnet to the parent subnet
     function createReleaseMsg(
         SubnetID calldata subnet,
         address signer,
@@ -98,6 +101,7 @@ library CrossMsgHelper {
             );
     }
 
+    // creates transfer message from the parent subnet to the child subnet
     function createFundMsg(
         SubnetID calldata subnet,
         address signer,
@@ -199,4 +203,8 @@ library CrossMsgHelper {
 
         return true;
     }
+
+    function validateCrossMessage(IpcEnvelope memory crossMsg) internal view returns (CrossMessageValidationOutcome)  {
+        return LibGateway.validateCrossMessage(crossMsg);
+    }
 }