Bridge 合约
Bridge 合约同时部署在Ethereum 和 Polygon Hermez 网络上，用于实现资产跨链。
**bridge 函数 **
brige 函数用于发起跨链操作，需要用户存款进去。
/**
* @notice Deposit add a new leaf to the merkle tree
* @param token Token address, 0 address is reserved for ether
* @param destinationNetwork Network destination
* @param destinationAddress Address destination
* @param amount Amount of tokens
*/
function bridge(
address token, // 待跨链的token
uint32 destinationNetwork, // 目标网络
address destinationAddress, // 接收者地址
uint256 amount // 金额
) public payable
-
跨链通过
wrappedToken形式； -
用户每发起一起存款，分生成Merkle树的一个叶子节点，更新
ExitRoot， 主网络上和Rollup的状态根分别为mainnetExitRoot和rollupExit； -
叶子节点的值为：
/** * @notice Given the leaf data returns the leaf value * @param originNetwork Origin Network * @param originTokenAddress Origin token address, 0 address is reserved for ether * @param destinationNetwork Destination network * @param destinationAddress Destination address * @param amount Amount of tokens * @param metadataHash Hash of the metadata */ function getLeafValue( uint32 originNetwork, address originTokenAddress, uint32 destinationNetwork, address destinationAddress, uint256 amount, bytes32 metadataHash ) public pure returns (bytes32) { return keccak256( abi.encodePacked( originNetwork, originTokenAddress, destinationNetwork, destinationAddress, amount, metadataHash ) ); }
claim 函数
claim 函数用户于通过跨链取回用户资产。
/**
* @notice Verify merkle proof and withdraw tokens/ether
* @param smtProof Smt proof
* @param index Index of the leaf
* @param mainnetExitRoot Mainnet exit root
* @param rollupExitRoot Rollup exit root
* @param originNetwork Origin network
* @param originTokenAddress Origin token address, 0 address is reserved for ether
* @param destinationNetwork Network destination, must be 0 ( mainnet)
* @param destinationAddress Address destination
* @param amount Amount of tokens
* @param metadata abi encoded metadata if any, empty otherwise
*/
function claim(
bytes32[] memory smtProof,
uint32 index,
bytes32 mainnetExitRoot,
bytes32 rollupExitRoot,
uint32 originNetwork,
address originTokenAddress,
uint32 destinationNetwork,
address destinationAddress,
uint256 amount,
bytes memory metadata
) public
- 通于
claimNullifier记录用户是否已取过款；
// Leaf index --> claimed
mapping(uint256 => bool) public claimNullifier;
-
确保
mainnetExitRoot和rollupExitRoot存在； -
根据
destinationNetwork选择mainnetExitRoot或rollupExitRoot来验证Merkle 证明：smtProof; -
若对应的
wrappedToken不存进，则进行部署； -
更新
claimNullifier； -
将资产发给用户
PoE (Proof of Efficiency) 合约
sequenceBatches 函数
只允许TrustedSequencer 提交 batch， 一次可以同时提交多个batch。
* @notice Allows a sequencer to send multiple batches of L2 transactions
* @param batches Struct array which the necessary data to append new batces ot the sequence
* Global exit root, timestamp and forced batches that are pop from the queue
*/
function sequenceBatches(BatchData[] memory batches)
public
onlyTrustedSequencer
-
BatchData的结构为：
/**
* @notice Struct which will be used to call sequenceBatches
* @param transactions L2 ethereum transactions EIP-155 with signature:
* rlp(nonce, gasprice, gasLimit, to, value, data, chainid, 0, 0,) || v || r || s
* @param globalExitRoot Global exit root of the batch
* @param timestamp Timestamp of the batch
* @param forceBatchesTimestamp Every element of the array indicates the timestamp of the forceBatch
* that will be popped from the queue and added to the sequence
*/
struct BatchData {
bytes transactions; // 包含的交易
bytes32 globalExitRoot; // 跨链状态根
uint64 timestamp; // 时间戳
uint64[] forceBatchesTimestamp; // 强制处理的Batch, 从queue添加到sequence
}
-
处理后
BatchData添加到下面的sequence中：// Queue of batches that defines the virtual state mapping(uint64 => SequencedBatch) public sequencedBatches;
其中SequenceBatch 为：
/**
* @notice Struct which will be stored in the sequence mapping
* @param batchHashData Hash containing the necessary information to process a batch:
* This field will contain: keccak256(bytes transactions || bytes32 globalExitRoot || address sequencer)
* Note that in case of forceBatch, the previous hash is stored in the ForceBatches mapping, and this will remain empty
* @param timestamp Timestamp of the batch
* @param forceBatchNum Indicates which forceBatch is sequenced, 0 if it's a regular batch
*/
struct SequencedBatch {
bytes32 batchHashData; // This field will contain the hashed data including the transactions
uint64 timestamp;
uint64 forceBatchNum;
}
verifyBatch 函数
由aggregator 提交证明，验证batch
/**
* @notice Allows an aggregator to verify a batch
* @param newLocalExitRoot New local exit root once the batch is processed
* @param newStateRoot New State root once the batch is processed
* @param numBatch Batch number that the aggregator intends to verify, used as a sanity check
* @param proofA zk-snark input
* @param proofB zk-snark input
* @param proofC zk-snark input
*/
function verifyBatch(
bytes32 newLocalExitRoot, // 新的`Exit` 根
bytes32 newStateRoot, // 新的状态根
uint64 numBatch, // 待证的Batch的数目
uint256[2] calldata proofA,
uint256[2][2] calldata proofB,
uint256[2] calldata proofC
) public
通过Groth16算法对证明验证通过后，会更新newStateRoot 和 newLocalExitRoot (即rollupExitRoot)。
forceBatch 函数
若trusted sequencer 离线， 任何人都可以通地forceBach 提交batch，
/**
* @notice Allows a sequencer/user to force a batch of L2 transactions.
* This should be used only in extreme cases where the trusted sequencer does not work as expected
* @param transactions L2 ethereum transactions EIP-155 with signature:
* rlp(nonce, gasprice, gasLimit, to, value, data, chainid, 0, 0,) || v || r || s
* @param maticAmount Max amount of MATIC tokens that the sender is willing to pay
*/
function forceBatch(bytes memory transactions, uint256 maticAmount)
public
isForceBatchAllowed
相应的 forceBatch 添加到 forcedBatches 队列中。
// Queue of forced batches with their associated data
mapping(uint64 => ForcedBatchData) public forcedBatches;
其中 forcedBatchData 结构为：
/**
* @notice Struct which will be stored in the force batch mapping
* @param batchHashData Hash containing the necessary information to process a batch:
* This field will contain: keccak256(bytes transactions || bytes32 globalExitRoot || address sequencer)
* @param maticFee Matic fee that will be payed to the aggregator
* @param minTimestamp Timestamp that will be an down limit of the batch once this is added to the sequence
*/
struct ForcedBatchData {
bytes32 batchHashData;
uint256 maticFee;
uint64 minTimestamp;
}
sequenceForceBatches 函数
若trusted sequencer 离线，在超时后，用户可以将 forcedBatch 添加到sequencedBatches 中进行处理。
/**
* @notice Allows anyone to sequence forced Batches if the trusted sequencer do not have done it in the timeout period
* Also allow in any time the trusted sequencer to append forceBatches to the sequence in order to avoid timeout issues
* @param numForcedBatches number of forced batches that will be added to the sequence
*/
function sequenceForceBatches(uint64 numForcedBatches)
public
isForceBatchAllowed
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