tornado-nova/contracts/TornadoPool.sol
2021-10-06 18:14:01 +03:00

244 lines
8.9 KiB
Solidity

// SPDX-License-Identifier: MIT
// https://tornado.cash
/*
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*/
pragma solidity ^0.7.0;
pragma experimental ABIEncoderV2;
import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import { IERC20Receiver, IERC6777 } from "./interfaces/IBridge.sol";
import { IVerifier } from "./interfaces/IVerifier.sol";
import "./MerkleTreeWithHistory.sol";
contract TornadoPool is MerkleTreeWithHistory, IERC20Receiver, ReentrancyGuard {
int256 public constant MAX_EXT_AMOUNT = 2**248;
uint256 public constant MAX_FEE = 2**248;
address public immutable governance;
IVerifier public immutable verifier2;
IVerifier public immutable verifier16;
IERC6777 public immutable token;
address public immutable omniBridge;
address public immutable l1Unwrapper;
uint256 public lastBalance;
uint256 public minimalWithdrawalAmount;
uint256 public maximumDepositAmount;
mapping(bytes32 => bool) public nullifierHashes;
struct ExtData {
address recipient;
int256 extAmount;
address relayer;
uint256 fee;
bytes encryptedOutput1;
bytes encryptedOutput2;
bool isL1Withdrawal;
}
struct Proof {
bytes proof;
bytes32 root;
bytes32[] inputNullifiers;
bytes32[2] outputCommitments;
uint256 publicAmount;
bytes32 extDataHash;
}
struct Account {
address owner;
bytes publicKey;
}
event NewCommitment(bytes32 commitment, uint256 index, bytes encryptedOutput);
event NewNullifier(bytes32 nullifier);
event PublicKey(address indexed owner, bytes key);
modifier onlyGovernance() {
require(msg.sender == governance, "only governance");
_;
}
/**
@dev The constructor
@param _verifier2 the address of SNARK verifier for 2 inputs
@param _verifier16 the address of SNARK verifier for 16 inputs
*/
constructor(
IVerifier _verifier2,
IVerifier _verifier16,
uint32 _levels,
address _hasher,
IERC6777 _token,
address _omniBridge,
address _l1Unwrapper,
address _governance
) MerkleTreeWithHistory(_levels, _hasher) {
verifier2 = _verifier2;
verifier16 = _verifier16;
token = _token;
omniBridge = _omniBridge;
l1Unwrapper = _l1Unwrapper;
governance = _governance;
}
function initialize(uint256 _minimalWithdrawalAmount, uint256 _maximumDepositAmount) external initializer {
_configureLimits(_minimalWithdrawalAmount, _maximumDepositAmount);
super._initialize();
}
function configureLimits(uint256 _minimalWithdrawalAmount, uint256 _maximumDepositAmount) public onlyGovernance {
_configureLimits(_minimalWithdrawalAmount, _maximumDepositAmount);
}
function transact(Proof memory _args, ExtData memory _extData) public {
if (_extData.extAmount > 0) {
// for deposits from L2
token.transferFrom(msg.sender, address(this), uint256(_extData.extAmount));
require(uint256(_extData.extAmount) <= maximumDepositAmount, "amount is larger than maximumDepositAmount");
}
_transact(_args, _extData);
}
function _transact(Proof memory _args, ExtData memory _extData) internal nonReentrant {
require(isKnownRoot(_args.root), "Invalid merkle root");
for (uint256 i = 0; i < _args.inputNullifiers.length; i++) {
require(!isSpent(_args.inputNullifiers[i]), "Input is already spent");
}
require(uint256(_args.extDataHash) == uint256(keccak256(abi.encode(_extData))) % FIELD_SIZE, "Incorrect external data hash");
require(_args.publicAmount == calculatePublicAmount(_extData.extAmount, _extData.fee), "Invalid public amount");
require(verifyProof(_args), "Invalid transaction proof");
for (uint256 i = 0; i < _args.inputNullifiers.length; i++) {
nullifierHashes[_args.inputNullifiers[i]] = true;
}
if (_extData.extAmount < 0) {
require(_extData.recipient != address(0), "Can't withdraw to zero address");
if (_extData.isL1Withdrawal) {
token.transferAndCall(omniBridge, uint256(-_extData.extAmount), abi.encodePacked(l1Unwrapper, _extData.recipient));
} else {
token.transfer(_extData.recipient, uint256(-_extData.extAmount));
}
require(uint256(-_extData.extAmount) >= minimalWithdrawalAmount, "amount is less than minimalWithdrawalAmount"); // prevents ddos attack to Bridge
}
if (_extData.fee > 0) {
token.transfer(_extData.relayer, _extData.fee);
}
lastBalance = token.balanceOf(address(this));
_insert(_args.outputCommitments[0], _args.outputCommitments[1]);
emit NewCommitment(_args.outputCommitments[0], nextIndex - 2, _extData.encryptedOutput1);
emit NewCommitment(_args.outputCommitments[1], nextIndex - 1, _extData.encryptedOutput2);
for (uint256 i = 0; i < _args.inputNullifiers.length; i++) {
emit NewNullifier(_args.inputNullifiers[i]);
}
}
function calculatePublicAmount(int256 _extAmount, uint256 _fee) public pure returns (uint256) {
require(_fee < MAX_FEE, "Invalid fee");
require(_extAmount > -MAX_EXT_AMOUNT && _extAmount < MAX_EXT_AMOUNT, "Invalid ext amount");
int256 publicAmount = _extAmount - int256(_fee);
return (publicAmount >= 0) ? uint256(publicAmount) : FIELD_SIZE - uint256(-publicAmount);
}
/** @dev whether a note is already spent */
function isSpent(bytes32 _nullifierHash) public view returns (bool) {
return nullifierHashes[_nullifierHash];
}
function verifyProof(Proof memory _args) public view returns (bool) {
if (_args.inputNullifiers.length == 2) {
return
verifier2.verifyProof(
_args.proof,
[
uint256(_args.root),
_args.publicAmount,
uint256(_args.extDataHash),
uint256(_args.inputNullifiers[0]),
uint256(_args.inputNullifiers[1]),
uint256(_args.outputCommitments[0]),
uint256(_args.outputCommitments[1])
]
);
} else if (_args.inputNullifiers.length == 16) {
return
verifier16.verifyProof(
_args.proof,
[
uint256(_args.root),
_args.publicAmount,
uint256(_args.extDataHash),
uint256(_args.inputNullifiers[0]),
uint256(_args.inputNullifiers[1]),
uint256(_args.inputNullifiers[2]),
uint256(_args.inputNullifiers[3]),
uint256(_args.inputNullifiers[4]),
uint256(_args.inputNullifiers[5]),
uint256(_args.inputNullifiers[6]),
uint256(_args.inputNullifiers[7]),
uint256(_args.inputNullifiers[8]),
uint256(_args.inputNullifiers[9]),
uint256(_args.inputNullifiers[10]),
uint256(_args.inputNullifiers[11]),
uint256(_args.inputNullifiers[12]),
uint256(_args.inputNullifiers[13]),
uint256(_args.inputNullifiers[14]),
uint256(_args.inputNullifiers[15]),
uint256(_args.outputCommitments[0]),
uint256(_args.outputCommitments[1])
]
);
} else {
revert("unsupported input count");
}
}
function register(Account memory _account) public {
require(_account.owner == msg.sender, "only owner can be registered");
_register(_account);
}
function _register(Account memory _account) internal {
emit PublicKey(_account.owner, _account.publicKey);
}
function registerAndTransact(
Account memory _account,
Proof memory _proofArgs,
ExtData memory _extData
) public {
register(_account);
transact(_proofArgs, _extData);
}
function onTokenBridged(
IERC6777 _token,
uint256 _amount,
bytes calldata _data
) external override {
(Proof memory _args, ExtData memory _extData) = abi.decode(_data, (Proof, ExtData));
require(_token == token, "provided token is not supported");
require(msg.sender == omniBridge, "only omni bridge");
require(_amount >= uint256(_extData.extAmount), "amount from bridge is incorrect");
require(token.balanceOf(address(this)) >= uint256(_extData.extAmount) + lastBalance, "bridge did not send enough tokens");
require(uint256(_extData.extAmount) <= maximumDepositAmount, "amount is larger than maximumDepositAmount");
_transact(_args, _extData);
}
function _configureLimits(uint256 _minimalWithdrawalAmount, uint256 _maximumDepositAmount) internal {
minimalWithdrawalAmount = _minimalWithdrawalAmount;
maximumDepositAmount = _maximumDepositAmount;
}
}