FeeDistributor

• Source code
• Deployed contract

FeeDistributor is a supplementary contract that holds the module's stETH reward shares while they are unallocated or claimable by Node Operators. FeeOracle reports the latest rewards-distribution Merkle root and CID, distribution log, newly claimable shares, and any rebate. The contract stores a history of these reports and transfers the reported rebate to the configured recipient.

Using a valid Merkle proof of a Node Operator's cumulative reward entitlement, Accounting pulls only the undistributed difference into that operator's bond. FeeDistributor records the cumulative shares already distributed to prevent duplicate claims.

State Variables

INITIALIZED_VERSION

uint64 internal constant INITIALIZED_VERSION = 3

STETH

IStETH public immutable STETH

ACCOUNTING

address public immutable ACCOUNTING

ORACLE

address public immutable ORACLE

treeRoot

The latest Merkle Tree root

bytes32 public treeRoot

treeCid

CID of the last published Merkle tree

string public treeCid

logCid

CID of the file with log for the last frame reported

string public logCid

distributedShares

Amount of stETH shares sent to the Accounting in favor of the NO

mapping(uint256 nodeOperatorId => uint256 distributed) public distributedShares

totalClaimableShares

Total Amount of stETH shares available for claiming by NOs

uint256 public totalClaimableShares

_distributionDataHistory

Array of the distribution data history

mapping(uint256 index => DistributionData) internal _distributionDataHistory

distributionDataHistoryCount

The number of records retrievable via getHistoricalDistributionData

uint256 public distributionDataHistoryCount

rebateRecipient

The address to transfer rebate to

address public rebateRecipient

Functions

onlyAccounting

modifier onlyAccounting() ;

onlyOracle

modifier onlyOracle() ;

constructor

constructor(address stETH, address accounting, address oracle) ;

initialize

Initialize contract from scratch. In case of a method call frontrun, the contract instance should be discarded. It is recommended to call this method in the same transaction as the deployment transaction and perform extensive deployment verification before using the contract instance.

function initialize(address admin, address _rebateRecipient) external reinitializer(INITIALIZED_VERSION);

finalizeUpgradeV3

This method is expected to be called only when the contract is upgraded from version 2 to version 3 for the existing version 2 deployment. If the version 3 contract is deployed from scratch, the initialize method should be used instead. To prevent possible frontrun this method should strictly be called in the same TX as the upgrade transaction and should not be called separately.

function finalizeUpgradeV3() external reinitializer(INITIALIZED_VERSION);

setRebateRecipient

Set address to send rebate to

function setRebateRecipient(address _rebateRecipient) external onlyRole(DEFAULT_ADMIN_ROLE);

Parameters

Name	Type	Description
_rebateRecipient	address	Address to send rebate to

distributeFees

Distribute fees to the Accounting in favor of the Node Operator

function distributeFees(uint256 nodeOperatorId, uint256 cumulativeFeeShares, bytes32[] calldata proof)
    external
    onlyAccounting
    returns (uint256 sharesToDistribute);

Parameters

Name	Type	Description
nodeOperatorId	uint256	ID of the Node Operator
cumulativeFeeShares	uint256	Total Amount of stETH shares earned as fees
proof	bytes32[]	Merkle proof of the leaf

Returns

Name	Type	Description
sharesToDistribute	uint256	Amount of stETH shares distributed

processOracleReport

Receive the data of the Merkle tree from the Oracle contract and process it

function processOracleReport(
    bytes32 _treeRoot,
    string calldata _treeCid,
    string calldata _logCid,
    uint256 distributed,
    uint256 rebate,
    uint256 refSlot
) external onlyOracle;

Parameters

Name	Type	Description
_treeRoot	bytes32	Root of the Merkle tree
_treeCid	string	IPFS CID of the tree
_logCid	string	IPFS CID of the log
distributed	uint256	Amount of the distributed shares
rebate	uint256	Amount of the rebate shares
refSlot	uint256	Reference slot of the report

recoverERC20

Allows sender to recover ERC20 tokens held by the contract

function recoverERC20(address token, uint256 amount) external override;

Parameters

Name	Type	Description
token	address	The address of the ERC20 token to recover
amount	uint256	The amount of the ERC20 token to recover

getInitializedVersion

Get the initialized version of the contract

function getInitializedVersion() external view returns (uint64);

pendingSharesToDistribute

Get the Amount of stETH shares that are pending to be distributed

function pendingSharesToDistribute() external view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	Amount shares that are pending to distribute

getHistoricalDistributionData

Get the historical record of distribution data

function getHistoricalDistributionData(uint256 index) external view returns (DistributionData memory);

Parameters

Name	Type	Description
index	uint256	Historical entry index

Returns

Name	Type	Description
<none>	DistributionData	Historical distribution data

getFeesToDistribute

Get the Amount of stETH shares that can be distributed in favor of the Node Operator

function getFeesToDistribute(uint256 nodeOperatorId, uint256 cumulativeFeeShares, bytes32[] calldata proof)
    public
    view
    returns (uint256 sharesToDistribute);

Parameters

Name	Type	Description
nodeOperatorId	uint256	ID of the Node Operator
cumulativeFeeShares	uint256	Total Amount of stETH shares earned as fees
proof	bytes32[]	Merkle proof of the leaf

Returns

Name	Type	Description
sharesToDistribute	uint256	Amount of stETH shares that can be distributed

hashLeaf

Get a hash of a leaf

Double hash the leaf to prevent second preimage attacks

function hashLeaf(uint256 nodeOperatorId, uint256 shares) public pure returns (bytes32);

Parameters

Name	Type	Description
nodeOperatorId	uint256	ID of the Node Operator
shares	uint256	Amount of stETH shares

Returns

Name	Type	Description
<none>	bytes32	Hash of the leaf

_setRebateRecipient

function _setRebateRecipient(address _rebateRecipient) internal;

_onlyAccounting

function _onlyAccounting() internal view;

_onlyOracle

function _onlyOracle() internal view;

_onlyRecoverer

function _onlyRecoverer() internal view override;