Technical Specifications

Dynamic Address Generation

• Contract: RouterRelay

  • addressForTokenDeposit: Generates a dynamic, single-use deposit address for token deposits based on user-supplied data, which can also be displayed as a QR code for easy scanning.

  • sendTokenDeposit: Deploys a DepositReceiver contract to handle the asset forwarding and initiate cross-chain transfers.

Asset Transfer and Forwarding

• Contract: ReceiverImplementation

• Purpose: Receives assets and forwards them as per user-specified data. Handles transaction failures with a refund mechanism.

• Core Components:

  • Data Structure: GenericData

    • callTo: Target address for forward operation (e.g., another contract).

    • approvalTo: Address for granting token approval if required.

    • data: Encoded transaction data for interaction.

    • srcToken: Address of the asset being transferred.

    • refundAddress: Address for refunds in case of transaction failure.

    • Native Asset Identifier: NATIVE_ASSETID to detect and handle native tokens (e.g., ETH).

  • Key Function: receiveAndSendToken

    • Verifies callTo and refundAddress are non-zero.

    • Identifies asset type (native/ERC20) and retrieves the balance.

    • Grants approval for ERC20 transfers if necessary and initiates a call to callTo with data.

    • If the transaction fails, refunds the balance to refundAddress.

    • Uses safeTransfer for ERC20 tokens, ensuring a secure refund process.

Temporary Deposit Receiver Contract

• Contract: DepositReceiver

• Purpose: Acts as a transient address to hold the user’s tokens and call ReceiverImplementation using delegatecall.

• Core Components:

  • Constructor:

    • Executes delegatecall to ReceiverImplementation for asset handling.

    • If delegatecall fails, reverts with the original error and refunds assets to refundAddress.

    • Self-destructs after transaction completion to clear storage and prevent reuse.

    • Fallback Function: Receives native tokens (e.g., ETH), allowing flexibility for handling WETH and similar assets.

Deterministic Address Calculation

• _depositAddress Function in RouterRelay.

• Uses CREATE2 for predictable address generation based on salt and genericData.

• Allows the creation of identical addresses across chains, simplifying cross-chain deposits.