IBorrower

​

Overview

​

Contract Details

• Source: src/interfaces/IBorrower.sol
• License: GPL-3.0-or-later
• Solidity: ^0.8.28

​

Functions

​

flashLoanAndCallBack

function flashLoanAndCallBack(
    address lender,
    IERC20 token,
    uint256 amount,
    bytes calldata callBackData
) external;

• lender: Address of the flash loan provider
• token: ERC-20 token to borrow
• amount: Amount of tokens to borrow
• callBackData: Data to pass back to the router unchanged

• Only callable by the registered Flash Loan Router

​

approve

function approve(
    IERC20 token,
    address target,
    uint256 amount
) external;

• token: ERC-20 token to approve
• target: Address to approve for spending (typically the lender)
• amount: Amount to approve

• Only callable by the settlement contract

​

settlementContract

function settlementContract() external view returns (ICowSettlement);

​

router

function router() external view returns (IFlashLoanRouter);

​

Protocol-Specific Implementations

​

Implementation Requirements

1. Restrict access: Only the router should be able to trigger flash loans via flashLoanAndCallBack()
2. Pass data unchanged: The callBackData must be forwarded to the router exactly as received
3. No fund retention: The borrower should not hold funds between transactions
4. Careful approvals: Manage token approvals carefully to prevent unauthorized transfers
5. Implement provider callback: Handle the provider-specific callback and forward to router.borrowerCallBack()

​

Security Considerations

• flashLoanAndCallBack() must only be callable by the authorized router
• approve() must only be callable by the settlement contract
• Callback data integrity must be maintained throughout the execution flow
• Token approvals should be managed with care to prevent exploitation

​

Next Steps