LayerZero Relayer Service Framework
LayerZero Contracts
These contracts are sourced from Etherscan and reproduced here in buildable form. The current LayerZero repo does not have some of these contracts published for whatever reason.
Trustless Omnichain Interoperability Protocol
a.k.a generic calldata messaging framework
Bridges like ThorChain, AnySwap, etc, are DEXes and require an intermediary token (RUNE, ANY, etc) to be minted and burned, and swapped for desired token at destination, requiring another transaction
With LayerZero, chain A can notify application on Chain B to grant user a token, using a single transaction without intermediary tokens. The exchange is handled by contracts on both sides, with
LayerZero delivering messages between the two
- Valid Delivery: -every message m sent over the network is coupled with a transaction t on the sender chain.
A message m is delivered to the receiver if and only if the associated transaction t is valid and has been committed on the sender chain Centralized exchanges gurantee valid delivery DEXes are not ideal because it requires converting sender token to intermediary token in one transaction, and then converting intermediary token to real token on destination in another transaction.
Trust is also required in the intermediate consensus layer that confirmation transactions and mints token at the destination.
user-facing interface to LayerZero. These are contracts implemented on each chain.
Uses Chainlink for Oracle to read block header from one chain and send it to another chain. Relayer is an off-chain service like Oracle, but instead it fetches the proof for a specified transaction.
The oracle and Relayer must be independent of each other, so then don't collude.
layerzero message contains:
t: the unique transaction identifier for Tdst: a global identifier pointing to a smart contract on chain Bpayload: any data that app A wishes to send to app Brelayer_args: arguments describing payments in formation in the event app A wishes to use the reference Relayer.
Validation will succeed if and only if the block header and transaction proof match the EVM library handles merkle-patricia tree validation for transactions on an evm block, using open-source implementation by Golden Gate
Trustless interchain transactions combines two independent entities: an Oracle that provides the block header a Relayer that provides proof associated with the aforementioned transaction "valid delivery" every message sent over the network is coupled with a transaction on the sender chain a message is delivered to the received only if the associated transaction is valid and has been committed on the sender chain "endpoints" allow user to send a message
LayerZero Endpoint is split into four modules:
- Communicator,
- Validator,
- Network,
- Libraries
A valid delivery can only happen if there's no collusion between Oracle and Relayer
Only the endpoint can be the caller of the function.
Relayer delivering the message is NOT the relayer the UA has configured.
User Application has configured an invalid proof library version for remote chainId
During message delivery, the Oracle didnt wait enough block confirmations as specified by the UA.
Invalid source sender of the message.
The LayerZero message specifies a different destination contract address than the relayer.
Endpoint.send() was flagged to be paid in tokens, but the address is invalid.
User Application needs to send more msg.value (see: Endpoint.estimateFees())
The specified _refundAddress is not payable, or invalid. (Try sending the exact amount)
The Oracle tried to update the data, but it was identical to what already existed.
setConfig() cannot set the specified inbound proof library version
setConfig() cannot set the specified outbound proof type
setConfig() does not know how to set this value
withdrawZRO() called by invalid address
Only a certain address can call withdraw on the UltraLightNode
withdrawZRO() called with invalid type
SEE LICENSE IN SPDX HEADERS