85 lines
3.2 KiB
Solidity
85 lines
3.2 KiB
Solidity
pragma solidity ^0.5.8;
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import "./Mixer.sol";
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import "@openzeppelin/contracts-ethereum-package/contracts/GSN/GSNRecipient.sol";
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import "@openzeppelin/contracts-ethereum-package/contracts/GSN/IRelayHub.sol";
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contract GSNMixer is Mixer, GSNRecipient {
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constructor(
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address _verifier,
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uint256 _mixDenomination,
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uint8 _merkleTreeHeight,
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uint256 _emptyElement,
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address payable _operator
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) Mixer(_verifier, _mixDenomination, _merkleTreeHeight, _emptyElement, _operator) public {
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}
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bool couldBeWithdrawn;
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modifier onlyHub() {
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require(msg.sender == getHubAddr(), "only relay hub");
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_;
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}
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function withdrawViaRelayer(uint256[2] memory a, uint256[2][2] memory b, uint256[2] memory c, uint256[5] memory input) public {
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uint256 root = input[0];
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uint256 nullifierHash = input[1];
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require(!nullifierHashes[nullifierHash], "The note has been already spent");
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require(isKnownRoot(root), "Cannot find your merkle root"); // Make sure to use a recent one
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require(verifier.verifyProof(a, b, c, input), "Invalid withdraw proof");
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nullifierHashes[nullifierHash] = true;
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couldBeWithdrawn = true;
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// we will process withdraw in postRelayedCall func
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}
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// gsn related stuff
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// this func is called by a Relayer via the RelayerHub before sending a tx
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function acceptRelayedCall(
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address /*relay*/,
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address /*from*/,
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bytes memory encodedFunction,
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uint256 /*transactionFee*/,
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uint256 /*gasPrice*/,
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uint256 /*gasLimit*/,
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uint256 /*nonce*/,
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bytes memory /*approvalData*/,
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uint256 /*maxPossibleCharge*/
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) public view returns (uint256, bytes memory) {
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// think of a withdraw dry-run
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if (!compareBytesWithSelector(encodedFunction, this.withdrawViaRelayer.selector)) {
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return (1, "Only withdrawViaRelayer can be called");
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}
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bytes memory recipient;
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assembly {
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let dataPointer := add(encodedFunction, 32)
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let nullifierPointer := mload(add(dataPointer, 292)) // 4 + (8 * 32) + (32) == selector + proof + root
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let recipientPointer := mload(add(dataPointer, 324)) // 4 + (8 * 32) + (32) + (32) == selector + proof + root + nullifier
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mstore(recipient, 64) // save array length
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mstore(add(recipient, 32), recipientPointer) // save recipient address
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mstore(add(recipient, 64), nullifierPointer) // save nullifier address
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}
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return (0, recipient);
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}
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// this func is called by RelayerHub right before calling a target func
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function preRelayedCall(bytes calldata /*context*/) external returns (bytes32) {}
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function postRelayedCall(bytes memory context, bool /*success*/, uint actualCharge, bytes32 /*preRetVal*/) public {}
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function compareBytesWithSelector(bytes memory data, bytes4 sel) internal pure returns (bool) {
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return data[0] == sel[0]
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&& data[1] == sel[1]
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&& data[2] == sel[2]
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&& data[3] == sel[3];
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}
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function withdrawFundsFromHub(uint256 amount, address payable dest) external {
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require(msg.sender == operator, "unauthorized");
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IRelayHub(getHubAddr()).withdraw(amount, dest);
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}
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function upgradeRelayHub(address newRelayHub) external {
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require(msg.sender == operator, "unauthorized");
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_upgradeRelayHub(newRelayHub);
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}
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}
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