LightRelayMaintainerProxy

LightRelayMaintainerProxy

The proxy contract that allows the relay maintainers to be refunded for the spent gas from the ReimbursementPool. When proving the next Bitcoin difficulty epoch, the maintainer calls the LightRelayMaintainerProxy which in turn calls the actual LightRelay contract.

lightRelay

contract ILightRelay lightRelay

isAuthorized

mapping(address => bool) isAuthorized

Stores the addresses that can maintain the relay. Those addresses are attested by the DAO.

The goal is to prevent a griefing attack by frontrunning relay maintainer which is responsible for retargetting the relay in the given round. The maintainer's transaction would revert with no gas refund. Having the ability to restrict maintainer addresses is also important in case the underlying relay contract has authorization requirements for callers.

retargetGasOffset

uint256 retargetGasOffset

Gas that is meant to balance the retarget overall cost. Can be

LightRelayUpdated

event LightRelayUpdated(address newRelay)

MaintainerAuthorized

event MaintainerAuthorized(address maintainer)

MaintainerDeauthorized

event MaintainerDeauthorized(address maintainer)

RetargetGasOffsetUpdated

event RetargetGasOffsetUpdated(uint256 retargetGasOffset)

onlyRelayMaintainer

modifier onlyRelayMaintainer()

onlyReimbursableAdmin

modifier onlyReimbursableAdmin()

constructor

constructor(contract ILightRelay _lightRelay, contract ReimbursementPool _reimbursementPool) public

updateLightRelay

function updateLightRelay(contract ILightRelay _lightRelay) external

Allows the governance to upgrade the LightRelay address.

The function does not implement any governance delay and does not check the status of the LightRelay. The Governance implementation needs to ensure all requirements for the upgrade are satisfied before executing this function.

authorize

function authorize(address maintainer) external

Authorizes the given address as a maintainer. Can only be called by the owner and the address of the maintainer must not be already authorized.

The function does not implement any governance delay.

Parameters

Name	Type	Description
maintainer	address	The address of the maintainer to be authorized.

deauthorize

function deauthorize(address maintainer) external

Deauthorizes the given address as a maintainer. Can only be called by the owner and the address of the maintainer must be authorized.

The function does not implement any governance delay.

Parameters

Name	Type	Description
maintainer	address	The address of the maintainer to be deauthorized.

updateRetargetGasOffset

function updateRetargetGasOffset(uint256 newRetargetGasOffset) external

Updates the values of retarget gas offset.

Can be called only by the contract owner. The caller is responsible for validating the parameter. The function does not implement any governance delay.

Parameters

Name	Type	Description
newRetargetGasOffset	uint256	New retarget gas offset.

retarget

function retarget(bytes headers) external

Wraps LightRelay.retarget call and reimburses the caller's transaction cost. Can only be called by an authorized relay maintainer.

See LightRelay.retarget function documentation.