L1SenderV2

Introduction

The L1SenderV2 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 Arbitrum (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 L1SenderV2 integrates with Uniswap v3, enabling it to swap the received tokens into wstETH. Once converted, the resulting wstETH is sent through the Arbitrum 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 Arbitrum Bridge:

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

   • It wraps stETH into wstETH and uses Arbitrum 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;

arbitrumBridgeConfig

Configuration details for bridging the stETH token via Arbitrum Bridge.

ArbitrumBridgeConfig public arbitrumBridgeConfig;

struct ArbitrumBridgeConfig {
  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.

layerZeroConfig

Configuration for the LayerZero cross-chain messaging.

LayerZeroConfig public layerZeroConfig;

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

L1SenderV2__init

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

function L1SenderV2__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 setLayerZeroConfig(
  LayerZeroConfig calldata layerZeroConfig_
) external onlyOwner

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

setArbitrumBridgeConfig

Allows the contract owner to update the Arbitrum Bridge configuration.

function setArbitrumBridgeConfig(
  ArbitrumBridgeConfig calldata newConfig_
) external onlyOwner

Name	Description
newConfig_	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 Arbitrum Bridge.

function sendWstETH(
  uint256 gasLimit_,
  uint256 maxFeePerGas_,
  uint256 maxSubmissionCost_
) external payable onlyOwner returns (bytes memory)

Name	Description
eth_value	Payable amount, value, in the ETH.
gasLimit_	Gas limit for the L2 execution.
maxFeePerGas_	Max fee for L2 execution.
maxSubmissionCost_	Base submission cost for the retryable ticket.

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.

Explanation

Uniswap UI can be used to detect the best route. With the help of this, it is possible to form all TX params exept deadline_

For example, we want to swap wstETH->tBTC (in real practice, you will do the swap in reverse USDC->wstETH, wBTC->wstETH...; this screenshot is for illustrative purposes only.

• tokens_: look at the order routing on the UI, [wstETH, wETH, tBTC].

• poolsFee_: look at the percent near the pool icons, [100, 2000]. It is equals to [0.01%, 0.2%].

• amountIn_: amount to swap, 0.00040790... wstETH, 407900000000000 wei in token decimals.

• amountOutMinimum_: amount to receive, 0.0000181086 tBTC, 18108600000000 wei in token decimals. You can decrease this value on 1-3%.

• deadline_: TX execution timestamp in seconds + 1 or 2 minutes.

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
user_	Recipient address on L2.
amount_	Amount of tokens to mint. Wei.
refundTo_	Address that receives any unspent msg.value.

Read functions

supportsInterface

Used for interface detection (ERC165). Returns true if the contract supports a specific interfaceId_. Supports IL1SenderV2, IERC165.

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

version

Returns the current version of the contract.

function version() external pure returns (uint256)