| description |
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An app for executing cross-chain function calls |
The Controller is an Abacus application that allows arbitrary function calls to be executed on remote chains, built according to the Router design pattern.
We expect the Controller to be most useful as a tool to extend the reach of a governance protocol to multiple chains. For example, the Controller can allow a DAO deployed on Ethereum to execute transactions on remote chains like Polygon, Avalanche, or Celo.
The primary function of the Controller is to execute calls on remote chains. This can be done by calling ControllerRouter.callRemote(), specifying the ID of the remote chain and the calls to make on that chain.
This results in a message being dispatched to the corresponding ControllerRouter on the remote chain, which executes the calls on that chain.
The ControllerRouter can also be directed to execute calls on the local chain by calling ControllerRouter.call().
struct Call {
bytes32 to;
bytes data;
}
/**
* @notice Dispatch calls on a remote chain via the remote ControllerRouter
* @param _destination The domain of the remote chain
* @param _calls The calls
*/
function callRemote(
uint32 _destination,
Call[] calldata _calls
) external onlyGovernor onlyNotInRecovery;
/**
* @notice Handle remote message and execute calls locally
* @param _msg The message containing the calls to execute
*/
function _handleCall(bytes29 _msg) internal;
/**
* @notice Execute calls locally
* @param _calls The calls to execute
*/
function call(Call[] calldata _calls) external onlyOwner;The controller is a permissioned role on the ControllerRouter that is allowed to dispatch calls to remote chains. Calls to ControllerRouter.callRemote() by addresses other than the controller will revert.
To use the Controller application to extend the control of a DAO to multiple chains, the controller of the ControllerRouters should be set to:
- On the DAO chain: The DAO address
- On all other chains: The null address
This gives the DAO the exclusive power to execute calls on remote chains.
Recovery mode provides a fail-safe mechanism for regaining control in the event of a catastrophic Abacus liveness failure.
Recovery mode can be triggered by the recoveryManager, a permissioned role on the ControllerRouter, and is subject to a time lock.
When a ControllerRouter is in recovery mode, it becomes owned by the recoveryManager, which gives the recoveryManager permission to trigger function calls on the local chain.
/**
* @notice Initiate the recovery timelock
* @dev callable by the recovery manager iff not in recovery
*/
function initiateRecoveryTimelock() external onlyNotInRecovery onlyRecoveryManager;
/**
* @notice Exit recovery mode
* @dev callable by the recovery manager iff in recovery
*/
function exitRecovery() external onlyInRecovery onlyRecoveryManager;