// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)pragmasolidity ^0.8.1;/**
* @dev Collection of functions related to the address type
*/libraryAddress{
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*
* [IMPORTANT]
* ====
* You shouldn't rely on `isContract` to protect against flash loan attacks!
*
* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
* constructor.
* ====
*/functionisContract(address account) internalviewreturns (bool) {
// This method relies on extcodesize/address.code.length, which returns 0// for contracts in construction, since the code is only stored at the end// of the constructor execution.return account.code.length>0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/functionsendValue(addresspayable recipient, uint256 amount) internal{
require(address(this).balance>= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{value: amount}("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain `call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/functionfunctionCall(address target, bytesmemory data) internalreturns (bytesmemory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/functionfunctionCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalreturns (bytesmemory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/functionfunctionCallWithValue(address target,
bytesmemory data,
uint256 value
) internalreturns (bytesmemory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/functionfunctionCallWithValue(address target,
bytesmemory data,
uint256 value,
stringmemory errorMessage
) internalreturns (bytesmemory) {
require(address(this).balance>= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
(bool success, bytesmemory returndata) = target.call{value: value}(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/functionfunctionStaticCall(address target, bytesmemory data) internalviewreturns (bytesmemory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/functionfunctionStaticCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalviewreturns (bytesmemory) {
require(isContract(target), "Address: static call to non-contract");
(bool success, bytesmemory returndata) = target.staticcall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/functionfunctionDelegateCall(address target, bytesmemory data) internalreturns (bytesmemory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/functionfunctionDelegateCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalreturns (bytesmemory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytesmemory returndata) = target.delegatecall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason using the provided one.
*
* _Available since v4.3._
*/functionverifyCallResult(bool success,
bytesmemory returndata,
stringmemory errorMessage
) internalpurereturns (bytesmemory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if presentif (returndata.length>0) {
// The easiest way to bubble the revert reason is using memory via assembly/// @solidity memory-safe-assemblyassembly {
let returndata_size :=mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
Contract Source Code
File 2 of 6: IERC20.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)pragmasolidity ^0.8.0;/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/interfaceIERC20{
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/eventTransfer(addressindexedfrom, addressindexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/eventApproval(addressindexed owner, addressindexed spender, uint256 value);
/**
* @dev Returns the amount of tokens in existence.
*/functiontotalSupply() externalviewreturns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/functionbalanceOf(address account) externalviewreturns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/functiontransfer(address to, uint256 amount) externalreturns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/functionallowance(address owner, address spender) externalviewreturns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/functionapprove(address spender, uint256 amount) externalreturns (bool);
/**
* @dev Moves `amount` tokens from `from` to `to` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/functiontransferFrom(addressfrom,
address to,
uint256 amount
) externalreturns (bool);
}
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)pragmasolidity ^0.8.0;import"../IERC20.sol";
import"../extensions/draft-IERC20Permit.sol";
import"../../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/librarySafeERC20{
usingAddressforaddress;
functionsafeTransfer(
IERC20 token,
address to,
uint256 value
) internal{
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
functionsafeTransferFrom(
IERC20 token,
addressfrom,
address to,
uint256 value
) internal{
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/functionsafeApprove(
IERC20 token,
address spender,
uint256 value
) internal{
// safeApprove should only be called when setting an initial allowance,// or when resetting it to zero. To increase and decrease it, use// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'require(
(value ==0) || (token.allowance(address(this), spender) ==0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
functionsafeIncreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal{
uint256 newAllowance = token.allowance(address(this), spender) + value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
functionsafeDecreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal{
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
uint256 newAllowance = oldAllowance - value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
}
functionsafePermit(
IERC20Permit token,
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) internal{
uint256 nonceBefore = token.nonces(owner);
token.permit(owner, spender, value, deadline, v, r, s);
uint256 nonceAfter = token.nonces(owner);
require(nonceAfter == nonceBefore +1, "SafeERC20: permit did not succeed");
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/function_callOptionalReturn(IERC20 token, bytesmemory data) private{
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that// the target address contains contract code and also asserts for success in the low-level call.bytesmemory returndata =address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length>0) {
// Return data is optionalrequire(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
Contract Source Code
File 5 of 6: SwapFeeRouter.sol
// SPDX-License-Identifier: MITpragmasolidity 0.8.16;import { IERC20, SafeERC20 } from"@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import { Ownable } from"./Ownable.sol";
// NOTE: There is no non-arbitrary upper-limit for the `feeBasisPoints`, and setting it above 10_000 just pauses the swap functions.contractSwapFeeRouterisOwnable{
errorETHTransferFailed(bytes errorData);
errorFeeBasisPointsNotRespected(uint256 expectedFeeBasisPoints_, uint256 actualFeeBasisPoints_);
errorContractNotWhitelisted(address callee);
errorRenterAttempted();
errorSwapCallFailed(bytes errorData);
eventContractAddedToWhitelist(addressindexed contract_);
eventContractRemovedFromWhitelist(addressindexed contract_);
eventETHPulled(addressindexed destination_, uint256 amount_);
eventFeeSet(uint256 feeBasisPoints_);
eventTokensPulled(addressindexed token_, addressindexed destination_, uint256 amount_);
uint256internal _locked =1;
uint256public feeBasisPoints; // 1 = 0.01%, 100 = 1%, 10_000 = 100%mapping(address=>bool) public isWhitelisted;
constructor(address owner_, uint256 feeBasisPoints_, address[] memory whitelist_) {
_setOwner(owner_);
_setFees(feeBasisPoints_);
_addToWhitelist(whitelist_);
}
modifiernoRenter() {
if (_locked ==2) revert RenterAttempted();
_locked =2;
_;
_locked =1;
}
modifierfeeBasisPointsRespected(uint256 feeBasisPoints_) {
// Revert if the expected fee is less than the current fee.if (feeBasisPoints_ < feeBasisPoints) revert FeeBasisPointsNotRespected(feeBasisPoints_, feeBasisPoints);
_;
}
functionswapWithFeesOnInput(address inAsset_,
uint256 swapAmount_,
uint256 feeBasisPoints_,
address swapContract_,
address tokenPuller_,
bytescalldata swapCallData_
) publicnoRenterfeeBasisPointsRespected(feeBasisPoints_) {
// Pull funds plus fees from caller.// NOTE: Assuming `swapCallData_` is correct, fees will remain in this contract.// NOTE: Worst case, assuming `swapCallData_` is incorrect/malicious, this contract loses nothing, but gains nothing.
SafeERC20.safeTransferFrom(IERC20(inAsset_), msg.sender, address(this), getAmountWithFees(swapAmount_, feeBasisPoints_));
// Perform the swap (set allowance, swap, unset allowance).// NOTE: This assume that the `swapCallData_` instructs the swapContract to send outAsset to correct destination.
_performSwap(inAsset_, swapAmount_, swapContract_, tokenPuller_, swapCallData_);
}
functionswapWithFeesOnOutput(address inAsset_,
uint256 swapAmount_,
address outAsset_,
uint256 feeBasisPoints_,
address swapContract_,
address tokenPuller_,
bytescalldata swapCallData_
) externalnoRenterfeeBasisPointsRespected(feeBasisPoints_) {
// Track this contract's starting outAsset balance to determine its increase later.uint256 startingOutAssetBalance = IERC20(outAsset_).balanceOf(address(this));
// Pull funds from caller.
SafeERC20.safeTransferFrom(IERC20(inAsset_), msg.sender, address(this), swapAmount_);
// Perform the swap (set allowance, swap, unset allowance).// NOTE: This assume that the `swapCallData_` instructs the swapContract to send outAsset to this contract.
_performSwap(inAsset_, swapAmount_, swapContract_, tokenPuller_, swapCallData_);
// Send the amount of outAsset the swap produced, minus fees, to the destination.
SafeERC20.safeTransfer(
IERC20(outAsset_),
msg.sender,
getAmountWithoutFees(
IERC20(outAsset_).balanceOf(address(this)) - startingOutAssetBalance,
feeBasisPoints
)
);
}
functionswapFromEthWithFeesOnInput(uint256 feeBasisPoints_,
address swapContract_,
bytescalldata swapCallData_
) externalpayablenoRenterfeeBasisPointsRespected(feeBasisPoints_) {
// Perform the swap (attaching ETH minus fees to call).// NOTE: This assume that the `swapCallData_` instructs the swapContract to send outAsset to correct destination.
_performSwap(getAmountWithoutFees(msg.value, feeBasisPoints_), swapContract_, swapCallData_);
}
functionswapFromEthWithFeesOnOutput(address outAsset_,
uint256 feeBasisPoints_,
address swapContract_,
bytescalldata swapCallData_
) externalpayablenoRenterfeeBasisPointsRespected(feeBasisPoints_) {
// Track this contract's starting outAsset balance to determine its increase later.uint256 startingOutAssetBalance = IERC20(outAsset_).balanceOf(address(this));
// Perform the swap (attaching ETH to call).// NOTE: This assume that the `swapCallData_` instructs the swapContract to send outAsset to this contract.
_performSwap(msg.value, swapContract_, swapCallData_);
// Send the amount of outAsset the swap produced, minus fees, to the destination.
SafeERC20.safeTransfer(
IERC20(outAsset_),
msg.sender,
getAmountWithoutFees(
IERC20(outAsset_).balanceOf(address(this)) - startingOutAssetBalance,
feeBasisPoints
)
);
}
functionswapToEthWithFeesOnInput(address inAsset_,
uint256 swapAmount_,
uint256 feeBasisPoints_,
address swapContract_,
address tokenPuller_,
bytescalldata swapCallData_
) externalfeeBasisPointsRespected(feeBasisPoints_) {
// NOTE: Ths is functionally the same as `swapWithFeesOnInput` since the output is irrelevant.// NOTE: No `noRenter` needed since `swapWithFeesOnInput` will check that.
swapWithFeesOnInput(inAsset_, swapAmount_, feeBasisPoints_, swapContract_, tokenPuller_, swapCallData_);
}
functionswapToEthWithFeesOnOutput(address inAsset_,
uint256 swapAmount_,
uint256 feeBasisPoints_,
address swapContract_,
address tokenPuller_,
bytescalldata swapCallData_
) externalnoRenterfeeBasisPointsRespected(feeBasisPoints_) {
// Track this contract's starting ETH balance to determine its increase later.uint256 startingETHBalance =address(this).balance;
// Pull funds from caller.
SafeERC20.safeTransferFrom(IERC20(inAsset_), msg.sender, address(this), swapAmount_);
// Perform the swap (set allowance, swap, unset allowance).// NOTE: This assume that the `swapCallData_` instructs the swapContract to send ETH to this contract.
_performSwap(inAsset_, swapAmount_, swapContract_, tokenPuller_, swapCallData_);
// Send the amount of ETH the swap produced, minus fees, to the destination, and revert if it fails.
_transferETH(
msg.sender,
getAmountWithoutFees(
address(this).balance- startingETHBalance,
feeBasisPoints_
)
);
}
functionaddToWhitelist(address[] calldata whitelist_) externalonlyOwner{
_addToWhitelist(whitelist_);
}
functionremoveFromWhitelist(address[] calldata whitelist_) externalonlyOwner{
_removeFromWhitelist(whitelist_);
}
functionsetFee(uint256 feeBasisPoints_) externalonlyOwner{
_setFees(feeBasisPoints_);
}
functionpullToken(address token_, address destination_) publiconlyOwner{
if (destination_ ==address(0)) revert ZeroAddress();
uint256 amount = IERC20(token_).balanceOf(address(this));
emit TokensPulled(token_, destination_, amount);
SafeERC20.safeTransfer(IERC20(token_), destination_, amount);
}
functionpullTokens(address[] calldata tokens_, address destination_) externalonlyOwner{
for (uint256 i; i < tokens_.length; ++i) {
pullToken(tokens_[i], destination_);
}
}
functionpullETH(address destination_) externalonlyOwner{
if (destination_ ==address(0)) revert ZeroAddress();
uint256 amount =address(this).balance;
emit ETHPulled(destination_, amount);
_transferETH(destination_, amount);
}
functiongetAmountWithFees(uint256 amountWithoutFees_, uint256 feeBasisPoints_) publicpurereturns (uint256 amountWithFees_) {
amountWithFees_ = (amountWithoutFees_ * (10_000+ feeBasisPoints_)) /10_000;
}
functiongetAmountWithoutFees(uint256 amountWithFees_, uint256 feeBasisPoints_) publicpurereturns (uint256 amountWithoutFees_) {
amountWithoutFees_ = (10_000* amountWithFees_) / (10_000+ feeBasisPoints_);
}
function_addToWhitelist(address[] memory whitelist_) internal{
for (uint256 i; i < whitelist_.length; ++i) {
address account = whitelist_[i];
isWhitelisted[whitelist_[i]] =true;
emit ContractAddedToWhitelist(account);
}
}
function_performSwap(address inAsset_, uint256 swapAmount_, address swapContract_, address tokenPuller_, bytescalldata swapCallData_) internal{
// Prevent calling contracts that are not whitelisted.if (!isWhitelisted[swapContract_]) revert ContractNotWhitelisted(swapContract_);
// Approve the contract that will pull inAsset.
IERC20(inAsset_).approve(tokenPuller_, swapAmount_);
// Call the swap contract as defined by `swapCallData_`, and revert if it fails.
( bool success, bytesmemory errorData ) = swapContract_.call(swapCallData_);
if (!success) revert SwapCallFailed(errorData);
// Un-approve the contract that pulled inAsset.// NOTE: This is important to prevent exploits that rely on allowances to arbitrary swapContracts to be non-zero after swap calls.
IERC20(inAsset_).approve(tokenPuller_, 0);
}
function_performSwap(uint256 swapAmount_, address swapContract_, bytescalldata swapCallData_) internal{
// Prevent calling contracts that are not whitelisted.if (!isWhitelisted[swapContract_]) revert ContractNotWhitelisted(swapContract_);
// Call the swap contract as defined by `swapCallData_`, and revert if it fails.
( bool success, bytesmemory errorData ) = swapContract_.call{ value: swapAmount_ }(swapCallData_);
if (!success) revert SwapCallFailed(errorData);
}
function_removeFromWhitelist(address[] memory whitelist_) internal{
for (uint256 i; i < whitelist_.length; ++i) {
address account = whitelist_[i];
isWhitelisted[whitelist_[i]] =false;
emit ContractRemovedFromWhitelist(account);
}
}
function_setFees(uint256 feeBasisPoints_) internal{
emit FeeSet(feeBasisPoints = feeBasisPoints_);
}
function_transferETH(address destination_, uint256 amount_) internal{
// NOTE: callers of this function are validating `destination_` to not be zero.
( bool success, bytesmemory errorData ) = destination_.call{ value: amount_ }("");
if (!success) revert ETHTransferFailed(errorData);
}
receive() externalpayable{}
}
Contract Source Code
File 6 of 6: draft-IERC20Permit.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)pragmasolidity ^0.8.0;/**
* @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
* https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
*
* Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
* presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
* need to send a transaction, and thus is not required to hold Ether at all.
*/interfaceIERC20Permit{
/**
* @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
* given ``owner``'s signed approval.
*
* IMPORTANT: The same issues {IERC20-approve} has related to transaction
* ordering also apply here.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `deadline` must be a timestamp in the future.
* - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
* over the EIP712-formatted function arguments.
* - the signature must use ``owner``'s current nonce (see {nonces}).
*
* For more information on the signature format, see the
* https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
* section].
*/functionpermit(address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external;
/**
* @dev Returns the current nonce for `owner`. This value must be
* included whenever a signature is generated for {permit}.
*
* Every successful call to {permit} increases ``owner``'s nonce by one. This
* prevents a signature from being used multiple times.
*/functionnonces(address owner) externalviewreturns (uint256);
/**
* @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
*/// solhint-disable-next-line func-name-mixedcasefunctionDOMAIN_SEPARATOR() externalviewreturns (bytes32);
}