mirror of
https://github.com/Instadapp/aave-protocol-v2.git
synced 2024-07-29 21:47:30 +00:00
Updated flashloans
This commit is contained in:
emilio
parent
ab88aa64bf
commit
16fc0d4971
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@ -153,21 +153,13 @@ contract LendingPool is VersionedInitializable, ILendingPool {
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emit Withdraw(asset, msg.sender, amount);
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}
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struct BorrowLocalVars {
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address asset;
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address user;
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uint256 amount;
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uint256 interestRateMode;
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bool releaseUnderlying;
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uint16 referralCode;
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}
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/**
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* @dev Allows users to borrow a specific amount of the reserve currency, provided that the borrower
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* already deposited enough collateral.
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* @param asset the address of the reserve
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* @param amount the amount to be borrowed
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* @param interestRateMode the interest rate mode at which the user wants to borrow. Can be 0 (STABLE) or 1 (VARIABLE)
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* @param referralCode a referral code for integrators
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**/
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function borrow(
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address asset,
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@ -176,71 +168,15 @@ contract LendingPool is VersionedInitializable, ILendingPool {
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uint16 referralCode
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) external override {
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_executeBorrow(
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BorrowLocalVars(asset, msg.sender, amount, interestRateMode, true, referralCode)
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);
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}
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/**
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* @dev Internal function to execute a borrowing action, allowing to transfer or not the underlying
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* @param vars Input struct for the borrowing action, in order to avoid STD errors
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**/
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function _executeBorrow(BorrowLocalVars memory vars) internal {
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ReserveLogic.ReserveData storage reserve = _reserves[vars.asset];
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UserConfiguration.Map storage userConfig = _usersConfig[vars.user];
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address oracle = _addressesProvider.getPriceOracle();
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uint256 amountInETH = IPriceOracleGetter(oracle).getAssetPrice(vars.asset).mul(vars.amount).div(
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10**reserve.configuration.getDecimals()
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);
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ValidationLogic.validateBorrow(
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reserve,
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vars.asset,
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vars.amount,
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amountInETH,
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vars.interestRateMode,
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MAX_STABLE_RATE_BORROW_SIZE_PERCENT,
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_reserves,
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_usersConfig[vars.user],
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_reservesList,
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oracle
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);
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//caching the current stable borrow rate
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uint256 userStableRate = reserve.currentStableBorrowRate;
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reserve.updateCumulativeIndexesAndTimestamp();
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if (
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ReserveLogic.InterestRateMode(vars.interestRateMode) == ReserveLogic.InterestRateMode.STABLE
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) {
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IStableDebtToken(reserve.stableDebtTokenAddress).mint(vars.user, vars.amount, userStableRate);
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} else {
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IVariableDebtToken(reserve.variableDebtTokenAddress).mint(vars.user, vars.amount);
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}
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address aToken = reserve.aTokenAddress;
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reserve.updateInterestRates(vars.asset, aToken, 0, vars.amount);
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uint256 reserveIndex = reserve.index;
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if (!userConfig.isBorrowing(reserveIndex)) {
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userConfig.setBorrowing(reserveIndex, true);
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}
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//if we reached this point and we need to, we can transfer
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if (vars.releaseUnderlying) {
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IAToken(aToken).transferUnderlyingTo(vars.user, vars.amount);
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}
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emit Borrow(
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vars.asset,
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vars.user,
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vars.amount,
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vars.interestRateMode,
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ReserveLogic.InterestRateMode(vars.interestRateMode) == ReserveLogic.InterestRateMode.STABLE
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? userStableRate
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: reserve.currentVariableBorrowRate,
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vars.referralCode
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ExecuteBorrowParams(
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asset,
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msg.sender,
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amount,
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interestRateMode,
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_reserves[asset].aTokenAddress,
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referralCode,
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true
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)
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);
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}
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@ -396,10 +332,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
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* @param asset the address of the reserve
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* @param useAsCollateral true if the user wants to user the deposit as collateral, false otherwise.
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**/
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function setUserUseReserveAsCollateral(address asset, bool useAsCollateral)
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external
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override
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{
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function setUserUseReserveAsCollateral(address asset, bool useAsCollateral) external override {
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ReserveLogic.ReserveData storage reserve = _reserves[asset];
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ValidationLogic.validateSetUseReserveAsCollateral(
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@ -473,13 +406,13 @@ contract LendingPool is VersionedInitializable, ILendingPool {
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}
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/**
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* @dev allows smartcontracts to access the liquidity of the pool within one transaction,
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* @dev allows smart contracts to access the liquidity of the pool within one transaction,
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* as long as the amount taken plus a fee is returned. NOTE There are security concerns for developers of flashloan receiver contracts
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* that must be kept into consideration. For further details please visit https://developers.aave.com
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* @param receiverAddress The address of the contract receiving the funds. The receiver should implement the IFlashLoanReceiver interface.
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* @param asset The address of the principal reserve
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* @param amount The amount requested for this flashloan
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* @param debtType Type of the debt to open if the flash loan is not returned. 0 -> Don't open any debt, just revert, 1 -> stable, 2 -> variable
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* @param mode Type of the debt to open if the flash loan is not returned. 0 -> Don't open any debt, just revert, 1 -> stable, 2 -> variable
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* @param params Variadic packed params to pass to the receiver as extra information
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* @param referralCode Referral code of the flash loan
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**/
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@ -487,7 +420,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
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address receiverAddress,
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address asset,
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uint256 amount,
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uint256 debtType,
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uint256 mode,
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bytes calldata params,
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uint16 referralCode
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) external override {
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@ -498,13 +431,12 @@ contract LendingPool is VersionedInitializable, ILendingPool {
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vars.premium = amount.mul(FLASHLOAN_PREMIUM_TOTAL).div(10000);
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require(vars.premium > 0, 'The requested amount is too small for a FlashLoan.');
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ReserveLogic.InterestRateMode debtMode = ReserveLogic.InterestRateMode(mode);
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ValidationLogic.validateFlashloan(debtMode, vars.premium);
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vars.receiver = IFlashLoanReceiver(receiverAddress);
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// Update of the indexes until the current moment
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reserve.updateCumulativeIndexesAndTimestamp();
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//transfer funds to the receiver
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IAToken(vars.aTokenAddress).transferUnderlyingTo(receiverAddress, amount);
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@ -513,60 +445,30 @@ contract LendingPool is VersionedInitializable, ILendingPool {
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vars.amountPlusPremium = amount.add(vars.premium);
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if (debtType == 0) { // To not fetch balance/allowance if no debt needs to be opened
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if (debtMode == ReserveLogic.InterestRateMode.NONE) {
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IERC20(asset).transferFrom(receiverAddress, vars.aTokenAddress, vars.amountPlusPremium);
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reserve.updateCumulativeIndexesAndTimestamp();
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reserve.cumulateToLiquidityIndex(IERC20(vars.aTokenAddress).totalSupply(), vars.premium);
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reserve.updateInterestRates(asset, vars.aTokenAddress, vars.premium, 0);
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emit FlashLoan(receiverAddress, asset, amount, vars.premium, referralCode);
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} else {
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vars.receiverBalance = IERC20(asset).balanceOf(receiverAddress);
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vars.receiverAllowance = IERC20(asset).allowance(receiverAddress, address(this));
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if (vars.receiverBalance >= vars.amountPlusPremium && vars.receiverAllowance >= vars.amountPlusPremium) {
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IERC20(asset).transferFrom(receiverAddress, vars.aTokenAddress, vars.amountPlusPremium);
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reserve.cumulateToLiquidityIndex(IERC20(vars.aTokenAddress).totalSupply(), vars.premium);
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reserve.updateInterestRates(asset, vars.aTokenAddress, vars.premium, 0);
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} else {
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if (debtType == 1 || debtType == 2) {
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// If the transfer didn't succeed, the receiver either didn't return the funds, or didn't approve the transfer.
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// We will try to pull all the available funds from the receiver and create a debt position with the rest owed
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// if it has collateral enough
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vars.availableBalance = (vars.receiverBalance > vars.receiverAllowance)
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? vars.receiverAllowance
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: vars.receiverBalance;
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if (vars.availableBalance > 0) {
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// If not enough premium, include as premium all the funds available to pull
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if (vars.availableBalance < vars.premium) {
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vars.premium = vars.availableBalance;
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}
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IERC20(asset).transferFrom(receiverAddress, vars.aTokenAddress, vars.availableBalance);
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reserve.cumulateToLiquidityIndex(
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IERC20(vars.aTokenAddress).totalSupply(),
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vars.premium
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);
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reserve.updateInterestRates(
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asset,
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vars.aTokenAddress,
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vars.premium,
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0
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);
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}
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_executeBorrow(
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BorrowLocalVars(
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asset,
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msg.sender,
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vars.amountPlusPremium.sub(vars.availableBalance),
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debtType,
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false,
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referralCode
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)
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);
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} else {
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revert("INSUFFICIENT_FUNDS_TO_PULL");
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}
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}
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// If the transfer didn't succeed, the receiver either didn't return the funds, or didn't approve the transfer.
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_executeBorrow(
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ExecuteBorrowParams(
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asset,
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msg.sender,
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vars.amountPlusPremium.sub(vars.availableBalance),
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mode,
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vars.aTokenAddress,
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referralCode,
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false
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)
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);
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}
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emit FlashLoan(receiverAddress, asset, amount, vars.premium, referralCode);
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}
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/**
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@ -783,9 +685,89 @@ contract LendingPool is VersionedInitializable, ILendingPool {
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return _reserves[asset].configuration;
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}
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// internal functions
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struct ExecuteBorrowParams {
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address asset;
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address user;
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uint256 amount;
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uint256 interestRateMode;
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address aTokenAddress;
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uint16 referralCode;
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bool releaseUnderlying;
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}
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/**
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* @notice internal functions
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* @dev Internal function to execute a borrowing action, allowing to transfer or not the underlying
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* @param vars Input struct for the borrowing action, in order to avoid STD errors
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**/
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function _executeBorrow(ExecuteBorrowParams memory vars) internal {
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ReserveLogic.ReserveData storage reserve = _reserves[vars.asset];
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UserConfiguration.Map storage userConfig = _usersConfig[msg.sender];
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address oracle = _addressesProvider.getPriceOracle();
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uint256 amountInETH = IPriceOracleGetter(oracle).getAssetPrice(vars.asset).mul(vars.amount).div(
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10**reserve.configuration.getDecimals()
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);
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ValidationLogic.validateBorrow(
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reserve,
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vars.asset,
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vars.amount,
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amountInETH,
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vars.interestRateMode,
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MAX_STABLE_RATE_BORROW_SIZE_PERCENT,
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_reserves,
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userConfig,
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_reservesList,
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oracle
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);
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uint256 reserveIndex = reserve.index;
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if (!userConfig.isBorrowing(reserveIndex)) {
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userConfig.setBorrowing(reserveIndex, true);
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}
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reserve.updateCumulativeIndexesAndTimestamp();
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//caching the current stable borrow rate
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uint256 currentStableRate = 0;
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if (
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ReserveLogic.InterestRateMode(vars.interestRateMode) == ReserveLogic.InterestRateMode.STABLE
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) {
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currentStableRate = reserve.currentStableBorrowRate;
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IStableDebtToken(reserve.stableDebtTokenAddress).mint(
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vars.user,
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vars.amount,
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currentStableRate
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);
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} else {
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IVariableDebtToken(reserve.variableDebtTokenAddress).mint(vars.user, vars.amount);
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}
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reserve.updateInterestRates(vars.asset, vars.aTokenAddress, 0, vars.releaseUnderlying ? vars.amount : 0);
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if(vars.releaseUnderlying){
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IAToken(vars.aTokenAddress).transferUnderlyingTo(msg.sender, vars.amount);
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}
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emit Borrow(
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vars.asset,
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msg.sender,
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vars.amount,
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vars.interestRateMode,
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ReserveLogic.InterestRateMode(vars.interestRateMode) == ReserveLogic.InterestRateMode.STABLE
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? currentStableRate
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: reserve.currentVariableBorrowRate,
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vars.referralCode
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);
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}
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/**
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* @dev adds a reserve to the array of the _reserves address
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@ -324,4 +324,14 @@ library ValidationLogic {
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'User deposit is already being used as collateral'
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);
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}
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/**
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* @dev validates a flashloan action
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* @param mode the flashloan mode (NONE = classic flashloan, STABLE = open a stable rate loan, VARIABLE = open a variable rate loan)
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* @param premium the premium paid on the flashloan
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**/
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function validateFlashloan(ReserveLogic.InterestRateMode mode, uint256 premium) internal pure {
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require(premium > 0, 'The requested amount is too small for a FlashLoan.');
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require(mode <= ReserveLogic.InterestRateMode.VARIABLE, 'Invalid flashloan mode selected');
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}
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}
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@ -36,14 +36,14 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
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await pool.deposit(weth.address, amountToDeposit, '0');
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});
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it('Takes ETH flashloan, returns the funds correctly', async () => {
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it('Takes WETH flashloan, returns the funds correctly', async () => {
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const {pool, deployer, weth} = testEnv;
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await pool.flashLoan(
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_mockFlashLoanReceiver.address,
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weth.address,
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ethers.utils.parseEther('0.8'),
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2,
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0,
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'0x10',
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'0'
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);
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@ -72,7 +72,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
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_mockFlashLoanReceiver.address,
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weth.address,
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'1000720000000000000',
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2,
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0,
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'0x10',
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'0'
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);
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@ -209,7 +209,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
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_mockFlashLoanReceiver.address,
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usdc.address,
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flashloanAmount,
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2,
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0,
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'0x10',
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'0'
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);
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@ -283,40 +283,6 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
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expect(callerDebt.toString()).to.be.equal('500450000', 'Invalid user debt');
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});
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it('Caller deposits 5 ETH as collateral, Takes a USDC flashloan, approves only partially funds. A loan for caller is created', async () => {
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const {usdc, pool, weth, users} = testEnv;
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const caller = users[3];
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await weth.connect(caller.signer).mint(await convertToCurrencyDecimals(weth.address, '5'));
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await weth.connect(caller.signer).approve(pool.address, APPROVAL_AMOUNT_LENDING_POOL);
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const amountToDeposit = await convertToCurrencyDecimals(weth.address, '5');
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await pool.connect(caller.signer).deposit(weth.address, amountToDeposit, '0');
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const flashloanAmount = await convertToCurrencyDecimals(usdc.address, '500');
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await _mockFlashLoanReceiver.setFailExecutionTransfer(false);
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await _mockFlashLoanReceiver.setAmountToApprove(flashloanAmount.div(2));
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await pool
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.connect(caller.signer)
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.flashLoan(_mockFlashLoanReceiver.address, usdc.address, flashloanAmount, 2, '0x10', '0');
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const {variableDebtTokenAddress} = await pool.getReserveTokensAddresses(usdc.address);
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const usdcDebtToken = await getContract<VariableDebtToken>(
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eContractid.VariableDebtToken,
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variableDebtTokenAddress
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);
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const callerDebt = await usdcDebtToken.balanceOf(caller.address);
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expect(callerDebt.toString()).to.be.equal('250450000', 'Invalid user debt');
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});
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it('Caller deposits 1000 DAI as collateral, Takes WETH flashloan, does not return the funds and selects revert as result', async () => {
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const {dai, pool, weth, users} = testEnv;
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