L1SenderV3

Introduction

The L1SenderV3 contract serves as a critical component in the cross-chain infrastructure of the protocol. Its primary responsibility is to transfer both reward data and yield assets from Ethereum (L1) to Base (L2), ensuring that users receive accurate MOR token rewards and that the protocol’s yield is available for conversion and distribution on L2.

The contract automatically receives deposit tokens from the Distributor contract. These tokens represent the yield generated by various DepositPools and may come in different ERC-20 formats depending on the underlying staking strategy. To unify these assets for bridging, the L1SenderV3 integrates with Uniswap v3, enabling it to swap the received tokens into wstETH. Once converted, the resulting wstETH is sent through the Lido Bridge to the L2TokenReceiverV2 contract on Arbitrum, ensuring the protocol’s yield is properly transferred and made available for liquidity and reward mechanisms on L2.

Key Responsibilities

1. Cross-chain reward messaging via LayerZero:

   • The contract communicates with the L2MessageReceiver on Arbitrum using LayerZero.

   • It packages the user’s reward data (including recipient address and reward amount) and sends it securely across chains.

   • This action is triggered by the DepositPool contract after calculating a user’s rewards.

   • On arrival to L2, the message is decoded, and MOR tokens are minted to the user.

2. Bridging stETH yield via Lido Bridge:

   • The contract manages the bridging of yield generated from stETH held by the Morpheus protocol.

   • It wraps stETH into wstETH and uses Lido Bridge to transfer tokens to the L2TokenReceiver contract.

3. Token configuration management:

   • The contract stores configuration data for both deposit and reward tokens:

     • Deposit token: the wrapped stETH token to be bridged.

     • Reward token: LayerZero configuration for sending mint instructions.

   • It handles dynamic updates to these configurations, allowing the protocol to change tokens or gateways without redeploying the contract.

4. Automated deposit handling:

   Receives various yield tokens directly from the Distributor contract.

5. Uniswap V3 integration for token conversion:

   Swaps received tokens into wstETH before bridging to L2.

Storage

stETH

The address of the original deposit token (e.g., stETH) before it is wrapped for cross-chain transfer.

address public stETH;

distributor

The address of the Distributor contract.

address public distributor;

tokenBridgeConfig

Configuration details for bridging the stETH token via Lido Bridge.

TokenBridgeConfig public tokenBridgeConfig;

struct TokenBridgeConfig {
  address token;
  address gateway;
  address receiver;
}

Name	Description
token	The address of wstETH.
gateway	The address of token's gateway, L1GatewayRouter
receiver	The L2MessageReceiver address.

messageBridgeConfig

Configuration for the LayerZero cross-chain messaging.

MessageBridgeConfig public messageBridgeConfig;

struct LayerZeroConfig {
  address gateway;
  address receiver;
  uint16 receiverChainId;
  address zroPaymentAddress;
  bytes adapterParams;
}

Name	Description
gateway	The LayerZero EnpointV1 address.
receiver	The L2MessageReceiver address.
receiverChainId	The receiver chain ID, from the LZ doc.
zroPaymentAddress	The LayerZero ZRO payment address for gas fees.
adapterParams	LayerZero adapter parameters used to customize messaging behavior.

Write functions for the contract owner

L1SenderV3__init

Initializes the contract. This is a one-time setup function, used during deployment via proxies.

function L1SenderV3__init() external initializer

setStETh

Allows the contract owner to set or update the address of the stETH token.

function setStETh(address value_) external onlyOwner

Name	Description
value_	The stETH token address

setDistributor

Allows the contract owner to set or update the address of the Distributor contract.

function setDistributor(address value_) public onlyOwner

Name	Description
value_	The Distributor contract address

setUniswapSwapRouter

Allows the contract owner to set the Uniswap v3 SwapRouter contract address.

function setUniswapSwapRouter(address value_) external onlyOwner

Name	Description
value_	The SwapRouter contract address

setLayerZeroConfig

Allows the contract owner to update the LayerZero MOR token configuration used for cross-chain messaging.

function setMessageBridgeConfig(
  MessageBridgeConfig calldata config_
) external onlyOwner

Name	Description
config_	Configuration for the LayerZero cross-chain messaging.

setArbitrumBridgeConfig

Allows the contract owner to update the Lido Bridge configuration.

function setTokenBridgeConfig(
  TokenBridgeConfig calldata config_
) external onlyOwner

Name	Description
config_	Configuration details for bridging the stETH token.

sendWstETH

Transfers tokens on the contract balance (e.g., stETH and wstETH) from L1 to L2 using the Lido Bridge.

function sendWstETH(uint32 l2Gas_, bytes calldata data_) external onlyOwner;

Name	Description
l2Gas_	Gas limit required to complete the deposit on L2.
data_	Optional data to forward to L2. This data is provided solely as a convenience for external contracts. Aside from enforcing a maximum length, these contracts provide no guarantees about its content.

swapExactInputMultihop

Allows the contract owner to swap deposit asset to the wstETH via Uniswap v3. Support multihop swaps (e.g. USDC/wETH, wETH/wstETH).

function swapExactInputMultihop(
  address[] calldata tokens_,
  uint24[] calldata poolsFee_,
  uint256 amountIn_,
  uint256 amountOutMinimum_,
  uint256 deadline_
) external onlyOwner returns (uint256)

Name	Description
tokens_	Tokens addresses. [USDC, wETH, wstETH]
poolsFee_	Uniswap v3 pool fee (e.g., 3000 = 0.3%).
amountIn_	The input token amount to swap. See the token decimals for the precision.
amountOutMinimum_	The minimal tokens amount at the end of swap (wstETH). See the token decimals for the precision.
deadline_	Expiry timestamp in seconds for the transaction.

Write functions for the Distributor contract

sendMintMessage

Sends a cross-chain message via LayerZero to L2, instructing minting of MOR tokens to the user.

function sendMintMessage(
  address user_, 
  uint256 amount_, 
  address refundTo_
) external payable

Name	Description
value (sendMintMessage)	Requires a bit of native gas token so the LZ relayer can complete the message delivery on the destination chain. This value can be estimated: https://docs.layerzero.network/v1/developers/evm/evm-guides/advanced/estimating-message-fees.
user_	Recipient address on L2.
amount_	Amount of MOR tokens to mint. Wei.
refundTo_	If the source transaction is cheaper than the amount of value passed, refund the additional amount to this address on the L1.

Read functions

supportsInterface

Used for interface detection (ERC165). Returns true if the contract supports a specific interfaceId_. Supports IL1SenderV3, IERC165.

function supportsInterface(bytes4 interfaceId_) external pure returns (bool)

version

Returns the current version of the contract.

function version() external pure returns (uint256)