LZCrossChainBridge

Git Source

Inherits: Owned, IVersioned, ReEnablerGracePeriod, ILZCrossChainBridge, Rescueable

Title: LZCrossChainBridge

Sends OHM to other chains using LayerZero V2.

It is a periphery contract, as it does not require any privileged access to the Olympus protocol. The user approves this contract for OHM, then calls sendOhm(). OHM is transferred to the gateway, which burns it and sends a LayerZero message.

Authorization for the lifecycle entry points splits responsibilities between the owner and the address pinned in configurator (expected to be an LZBridgeAndDelegateConfig instance, i.e. the timelock policy):

• enable, disable, rescue, and the bootstrap setConfigurator call are restricted to the owner.
• setGateway, setReEnabler, setGracePeriod, and the post-bootstrap rotation of setConfigurator are restricted to the current configurator.
• reEnable is restricted to the configured reEnabler, which is set in the constructor and may be updated or cleared via setReEnabler. A re-enable additionally requires that the grace window since the last transition has not yet elapsed.

Constants

OHM

Returns the OHM token address.

address public immutable override OHM;

Returns

Name	Type	Description
<none>	address

State Variables

gateway

Returns the LZBridgeGateway address.

address public override gateway;

Returns

Name	Type	Description
<none>	address

reEnabler

Returns the address authorized to call reEnable().

Returns address(0) when no re-enabler has been configured.

address public override reEnabler;

Returns

Name	Type	Description
<none>	address

configurator

Returns the configurator address (an LZBridgeAndDelegateConfig instance).

Returns address(0) before the owner has performed the bootstrap call.

address public override configurator;

Returns

Name	Type	Description
<none>	address

Functions

onlyConfigurator

Reverts if msg.sender is not the currently configured configurator.

The check also rejects calls while the configurator variable is unset, i.e. before the owner has performed the bootstrap setConfigurator call.

modifier onlyConfigurator();

_requireConfigurator

Reverts if msg.sender is not the currently configured configurator.

The check also rejects calls while the configurator variable is unset, i.e. before the owner has performed the bootstrap setConfigurator call.

function _requireConfigurator() private view;

constructor

constructor(
        address ohm_,
        address owner_,
        address gateway_,
        address reEnabler_,
        uint32 grace_
    ) Owned(owner_) ReEnablerGracePeriod(grace_);

Parameters

Name	Type	Description
ohm_	address
owner_	address
gateway_	address
reEnabler_	address
grace_	uint32

VERSION

Returns the version of the contract

function VERSION() external pure override returns (uint8 major, uint8 minor);

Returns

Name	Type	Description
major	uint8	- Major version upgrade indicates breaking change to the interface.
minor	uint8	- Minor version change retains backward-compatible interface.

sendOhm

Sends OHM to a destination chain via the gateway.

Reverts if:

• The bridge is not enabled.
• amount_ is zero.
• The user has insufficient OHM balance or approval.
• The gateway reverts (e.g. no peer configured, rate limit exceeded, gateway not enabled).

function sendOhm(
        uint32 dstEid_,
        address to_,
        uint256 amount_
    ) external payable override givenEnabled;

Parameters

Name	Type	Description
dstEid_	uint32	The LayerZero destination endpoint ID.
to_	address	The recipient address on the destination chain.
amount_	uint256	The amount of OHM to send.

setGateway

Sets the gateway address.

Reverts if:

• The caller is not the configurator.
• gateway_ is the zero address.

function setGateway(address gateway_) external override onlyConfigurator;

Parameters

Name	Type	Description
gateway_	address	The new gateway address.

_authorizeRescue

Hook for subclasses to authorize the caller of rescue().

Implementations MUST revert if the caller is not authorised.

function _authorizeRescue() internal view override onlyOwner;

setReEnabler

Sets the address authorized to call reEnable().

Reverts if:

• The caller is not the configurator.

function setReEnabler(address reEnabler_) external override onlyConfigurator;

Parameters

Name	Type	Description
reEnabler_	address	The new re-enabler address, or address(0) to clear.

setConfigurator

Sets the configurator address.

In both cases the new configurator must implement ILZBridgeAndDelegateConfig

via ERC-165 to prevent the bridge from being bricked by an incompatible address.

Reverts if:

• The bootstrap call is made by anyone other than the owner.
• A subsequent rotation is made by anyone other than the current configurator.
• newConfigurator_ is the zero address.
• newConfigurator_ does not implement ILZBridgeAndDelegateConfig via ERC-165.

function setConfigurator(address newConfigurator_) external override;

Parameters

Name	Type	Description
newConfigurator_	address	The new configurator address.

estimateSendFee

Estimates the fee for sending OHM to a destination chain.

Proxies to the gateway's estimateSendFee function with empty extra options.

function estimateSendFee(
        uint32 dstEid_,
        address to_,
        uint256 amount_
    ) external view override returns (MessagingFee memory fee);

Parameters

Name	Type	Description
dstEid_	uint32	The LayerZero destination endpoint ID.
to_	address	The recipient address on the destination chain.
amount_	uint256	The amount of OHM to send.

Returns

Name	Type	Description
fee	MessagingFee	The estimated messaging fee (native + lzToken (unused)).

sendable

Returns the current outbound capacity for a destination endpoint, with the in-flight amount decayed against the current timestamp.

Proxies to the gateway's sendable function.

function sendable(
        uint32 dstEid_
    ) external view override returns (uint256 inFlight, uint256 available);

Parameters

Name	Type	Description
dstEid_	uint32	The LayerZero destination endpoint ID.

Returns

Name	Type	Description
inFlight	uint256	The decayed outbound in-flight amount at the current timestamp.
available	uint256	The amount that may still be sent to the destination before the outbound rate limit is exceeded.

receivable

Returns the current inbound capacity for a source endpoint, with the in-flight amount decayed against the current timestamp.

Proxies to the gateway's receivable function.

function receivable(
        uint32 srcEid_
    ) external view override returns (uint256 inFlight, uint256 available);

Parameters

Name	Type	Description
srcEid_	uint32	The LayerZero source endpoint ID.

Returns

Name	Type	Description
inFlight	uint256	The decayed inbound in-flight amount at the current timestamp.
available	uint256	The amount that may still be received from the source before the inbound rate limit is exceeded.

supportsInterface

function supportsInterface(
        bytes4 interfaceId
    ) public view override(ReEnablerGracePeriod, Rescueable) returns (bool);

Parameters

Name	Type	Description
interfaceId	bytes4

Returns

Name	Type	Description
<none>	bool

_authorizeEnable

Validates that the caller is permitted to enable the contract.

Reverts if:

• The caller is not authorized to perform the enable.

The function is invoked from enable before any state mutation. The data_ payload is forwarded unchanged so that authorization may depend on the contents of the call.

function _authorizeEnable(bytes calldata) internal view override;

Parameters

Name	Type	Description
_	bytes	The calldata payload passed to enable.

_authorizeDisable

Validates that the caller is permitted to disable the contract.

Reverts if:

• The caller is not authorized to perform the disable.

The function is invoked from disable before any state mutation. The data_ payload is forwarded unchanged so that authorization may depend on the contents of the call.

function _authorizeDisable(bytes calldata) internal view override;

Parameters

Name	Type	Description
_	bytes	The calldata payload passed to disable.

_authorizeReEnable

The function is invoked from reEnable after the state checks pass and before

any state mutation.

Reverts if:

• The caller is not authorized to perform the re-enable.

Reverts if msg.sender is not the configured re-enabler. The check also rejects calls when no re-enabler has been set (i.e. reEnabler == address(0)).

function _authorizeReEnable() internal view override;

_authorizeSetGracePeriod

Validates that the caller is permitted to update the grace window.

Reverts if:

• The caller is not authorized to update the grace window.

Restricts setGracePeriod to the address pinned in configurator (expected to be the LZBridgeAndDelegateConfig timelock policy).

function _authorizeSetGracePeriod() internal view override;

validateSetGateway

Validates the payload that would be passed to setGateway.

Reverts if:

• gateway_ is the zero address.

function validateSetGateway(address gateway_) public pure override;

Parameters

Name	Type	Description
gateway_	address	The candidate gateway address.

validateSetConfigurator

Validates the payload that would be passed to setConfigurator.

Reverts if:

• newConfigurator_ is the zero address.
• newConfigurator_ does not implement ILZBridgeAndDelegateConfig via ERC-165.

function validateSetConfigurator(address newConfigurator_) public view override;

Parameters

Name	Type	Description
newConfigurator_	address	The candidate configurator address.

_onlyOwner

function _onlyOwner() private view;

_setGateway

function _setGateway(address gateway_) private;

Parameters

Name	Type	Description
gateway_	address

_setReEnabler

function _setReEnabler(address reEnabler_) private;

Parameters

Name	Type	Description
reEnabler_	address

_requireNonzeroAddress

function _requireNonzeroAddress(address address_, string memory parameter_) private pure;

Parameters

Name	Type	Description
address_	address
parameter_	string