Add aggregation hook for V3

solidity/contracts/hooks/AggregationHook.sol

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity >=0.8.0;
+
+/*@@@@@@@       @@@@@@@@@
+ @@@@@@@@@       @@@@@@@@@
+  @@@@@@@@@       @@@@@@@@@
+   @@@@@@@@@       @@@@@@@@@
+    @@@@@@@@@@@@@@@@@@@@@@@@@
+     @@@@@  HYPERLANE  @@@@@@@
+    @@@@@@@@@@@@@@@@@@@@@@@@@
+   @@@@@@@@@       @@@@@@@@@
+  @@@@@@@@@       @@@@@@@@@
+ @@@@@@@@@       @@@@@@@@@
+@@@@@@@@@       @@@@@@@@*/
+
+import {IPostDispatchHook} from "../interfaces/hooks/IPostDispatchHook.sol";
+import {MetaProxy} from "../libs/MetaProxy.sol";
+
+contract AggregationHook is IPostDispatchHook {
+    event SuccessfulAggregationHookCall(address indexed hook);
+    event ErroneousAggregationHookCall(address indexed hook);
+
+    function postDispatch(bytes calldata metadata, bytes calldata message)
+        external
+        payable
+        override
+    {
+        address[] memory _hooks = hooks(message);
+        uint256 count = _hooks.length;
+        for (uint256 i = 0; i < count; i++) {
+            try
+                IPostDispatchHook(_hooks[i]).postDispatch{value: msg.value}(
+                    metadata,
+                    message
+                )
+            {
+                emit SuccessfulAggregationHookCall(_hooks[i]);
+            } catch {
+                emit ErroneousAggregationHookCall(_hooks[i]);
+            }
+        }
+    }
+
+    function quoteDispatch(bytes calldata metadata, bytes calldata message)
+        external
+        view
+        override
+        returns (uint256)
+    {
+        address[] memory _hooks = hooks(message);
+        uint256 count = _hooks.length;
+        uint256 total = 0;
+        for (uint256 i = 0; i < count; i++) {
+            try
+                IPostDispatchHook(_hooks[i]).quoteDispatch(metadata, message)
+            returns (uint256 _quote) {
+                total += _quote;
+            } catch {}
+        }
+        return total;
+    }
+
+    function hooks(bytes calldata) public pure returns (address[] memory) {
+        return abi.decode(MetaProxy.metadata(), (address[]));
+    }
+}

solidity/contracts/hooks/ConfigFallbackDomainRoutingHook.sol

@@ -49,6 +49,21 @@ contract ConfigFallbackDomainRoutingHook is IPostDispatchHook {
         return _getConfiguredHook(message).quoteDispatch(metadata, message);
     }
 
+    function quoteDispatch(bytes calldata metadata, bytes calldata message)
+        public
+        view
+        returns (uint256)
+    {
+        IPostDispatchHook configuredHook = customHooks[message.senderAddress()][
+            message.destination()
+        ][message.recipient()];
+        if (address(configuredHook) == address(0)) {
+            configuredHook = mailbox.defaultHook();
+        }
+
+        return configuredHook.quoteDispatch(metadata, message);
+    }
+
     function setHook(
         uint32 destinationDomain,
         bytes32 recipient,