BridgeSettler UNDERPAYMENT_CHECK action

CHANGELOG.md

@@ -49,6 +49,7 @@ Master list of UniV3 forks:
 ### Non-breaking changes
 
 * Add Aerodrome Slipstream V3.1 UniswapV3 fork to Base
+* Added UNDERPAYMENT_CHECK action to BridgeSettlerBase.
 
 ## 2025-10-02
 

src/bridge/BridgeSettler.sol

@@ -6,7 +6,7 @@ import {revertActionInvalid} from "../core/SettlerErrors.sol";
 import {CalldataDecoder} from "../SettlerBase.sol";
 import {UnsafeMath} from "../utils/UnsafeMath.sol";
 import {ISignatureTransfer} from "@permit2/interfaces/ISignatureTransfer.sol";
-import {ISettlerActions} from "../ISettlerActions.sol";
+import {IBridgeSettlerActions} from "./IBridgeSettlerActions.sol";
 import {Permit2PaymentTakerSubmitted} from "../core/Permit2Payment.sol";
 
 interface IBridgeSettlerTakerSubmitted {
@@ -22,7 +22,7 @@ abstract contract BridgeSettler is IBridgeSettlerTakerSubmitted, Permit2PaymentT
     }
 
     function _dispatchVIP(uint256 action, bytes calldata data) internal virtual returns (bool) {
-        if (action == uint32(ISettlerActions.TRANSFER_FROM.selector)) {
+        if (action == uint32(IBridgeSettlerActions.TRANSFER_FROM.selector)) {
             (address recipient, ISignatureTransfer.PermitTransferFrom memory permit, bytes memory sig) =
                 abi.decode(data, (address, ISignatureTransfer.PermitTransferFrom, bytes));
             (ISignatureTransfer.SignatureTransferDetails memory transferDetails,) =

src/bridge/BridgeSettlerBase.sol

@@ -14,6 +14,7 @@ import {FastDeployer} from "../deployer/FastDeployer.sol";
 import {Basic} from "../core/Basic.sol";
 import {Relay} from "../core/Relay.sol";
 import {LayerZeroOFT} from "../core/LayerZeroOFT.sol";
+import {Underpayment} from "../core/SettlerErrors.sol";
 
 abstract contract BridgeSettlerBase is Basic, Relay, LayerZeroOFT {
     using SafeTransferLib for IERC20;
@@ -89,6 +90,16 @@ abstract contract BridgeSettlerBase is Basic, Relay, LayerZeroOFT {
         } else if (action == uint32(IBridgeSettlerActions.BRIDGE_TO_LAYER_ZERO_OFT.selector)) {
             (IERC20 token, uint256 nativeFee, address oft, bytes memory sendData) = abi.decode(data, (IERC20, uint256, address, bytes));
             bridgeLayerZeroOFT(token, nativeFee, oft, sendData);
+        } else if (action == uint32(IBridgeSettlerActions.UNDERPAYMENT_CHECK.selector)) {
+            (uint256 msgValueMin) = abi.decode(data, (uint256));
+            if (msg.value < msgValueMin) {
+                assembly ("memory-safe") {
+                    mstore(0x00, 0xd17e444b) // selector for `Underpayment(uint256,uint256)`
+                    mstore(0x20, msgValueMin)
+                    mstore(0x40, callvalue())
+                    revert(0x1c, 0x44)
+                }
+            }
         } else {
             return false;
         }

src/bridge/IBridgeSettlerActions.sol

@@ -11,6 +11,9 @@ interface IBridgeSettlerActions {
     /// @dev Execute swaps in Settler
     function SETTLER_SWAP(address token, uint256 amount, address settler, bytes calldata settlerData) external;
 
+    /// @dev msgValueMin is interpreted as an lower bound on the expected msg.value, not as an exact specification
+    function UNDERPAYMENT_CHECK(uint256 msgValueMin) external;
+
     /// @dev Bridge through a Bridge that follows the approval, transferFrom(msg.sender) interaction
     /// Pre-req: Funded
     function BASIC(address bridgeToken, uint256 bps, address pool, uint256 offset, bytes calldata data) external;

src/core/SettlerErrors.sol

@@ -115,3 +115,6 @@ error NotConverged();
 /// @notice Thrown when the encoded pool manager ID as part of PancakeSwap Infinity fill is not on
 ///         the list of recognized pool managers.
 error UnknownPoolManagerId(uint8 poolManagerId);
+
+/// @notice Thrown when the `msg.value` is less than the minimum expected value.
+error Underpayment(uint256 msgValueMin, uint256 msgValueActual);