AccrossBridge

Inherits: BaseBridge, IBridge, IAcrossReceiverV3, ReentrancyGuard

Title: AcrossBridge

Author: Merge Layers Inc.

Bridge integration for Across V3 used by the rebalancer

State Variables

SLIPPAGE_PRECISION

Precision used for slippage calculations

uint256 private constant SLIPPAGE_PRECISION = 1e5

ACROSS_SPOKE_POOL

Across spoke pool address

address public immutable ACROSS_SPOKE_POOL

MAX_SLIPPAGE

Maximum allowed slippage in basis points

uint256 public immutable MAX_SLIPPAGE

REBALANCER

Rebalancer contract address

address public immutable REBALANCER

whitelistedRelayers

Whitelisted relayers per destination chain

mapping(uint32 dstChainId => mapping(address relayer => bool isWhitelisted)) public whitelistedRelayers

Functions

onlySpokePool

Modifier to restrict access to only the spoke pool

modifier onlySpokePool() ;

constructor

Initializes the Across bridge

constructor(address _roles, address _spokePool, address _rebalancer) BaseBridge(_roles);

Parameters

Name	Type	Description
`_roles`	`address`	Address of the roles contract
`_spokePool`	`address`	Address of the Across spoke pool
`_rebalancer`	`address`	Address of the rebalancer contract

setWhitelistedRelayer

Whitelists or removes a relayer for a destination chain

function setWhitelistedRelayer(uint32 _dstId, address _relayer, bool status) external onlyBridgeConfigurator;

Parameters

Name	Type	Description
`_dstId`	`uint32`	The destination chain ID
`_relayer`	`address`	The relayer address to update
`status`	`bool`	Whether the relayer is whitelisted

handleV3AcrossMessage

handles AcrossV3 SpokePool message

function handleV3AcrossMessage(
    address tokenSent,
    uint256 amount,
    address, /* relayer is unused */
    bytes calldata message
)
    external
    onlySpokePool
    nonReentrant;

Parameters

Name	Type	Description
`tokenSent`	`address`	the token address received
`amount`	`uint256`	the token amount
`<none>`	`address`
`message`	`bytes`	the custom message sent from source

sendMsg

rebalance through bridge

function sendMsg(
    uint256 _extractedAmount,
    address _market,
    uint32 _dstChainId,
    address _token,
    bytes calldata _message,
    bytes calldata /* _bridgeData */
) external payable onlyRebalancer;

Parameters

Name	Type	Description
`_extractedAmount`	`uint256`	extracted amount for rebalancing
`_market`	`address`	destination address
`_dstChainId`	`uint32`	destination chain id
`_token`	`address`	the token to rebalance
`_message`	`bytes`	operation message data
`<none>`	`bytes`

isRelayerWhitelisted

Returns whether an address is whitelisted as relayer for a destination chain

function isRelayerWhitelisted(uint32 dstChain, address relayer) external view returns (bool);

Parameters

Name	Type	Description
`dstChain`	`uint32`	The destination chain ID
`relayer`	`address`	The relayer address

Returns

Name	Type	Description
`<none>`	`bool`	isWhitelisted True if relayer is whitelisted

getFee

computes fee for bridge operation

function getFee(
    uint32,
    /* _dstChainId */
    bytes calldata,
    /* _message */
    bytes calldata /* _bridgeData */
)
    external
    pure
    returns (uint256);

Parameters

Name	Type	Description
`<none>`	`uint32`
`<none>`	`bytes`
`<none>`	`bytes`

Returns

Name	Type	Description
`<none>`	`uint256`	fee Computed bridge fee

_depositV3Now

Deposits funds into Across spoke pool for immediate relay

function _depositV3Now(bytes calldata _message, address _token, uint32 _dstChainId, address _market) private;

Parameters

Name	Type	Description
`_message`	`bytes`	Encoded Across message
`_token`	`address`	Token being transferred
`_dstChainId`	`uint32`	Destination chain ID
`_market`	`address`	Market address encoded in the message

_decodeMessage

Decodes the Across message payload

function _decodeMessage(bytes calldata _message) private pure returns (DecodedMessage memory messageData);

Parameters

Name	Type	Description
`_message`	`bytes`	Encoded message data

Returns

Name	Type	Description
`messageData`	`DecodedMessage`	The decoded message struct

Events

Rebalanced

Emitted when funds are rebalanced to a market

event Rebalanced(address indexed market, uint256 amount);

Parameters

Name	Type	Description
`market`	`address`	The market receiving funds
`amount`	`uint256`	The amount rebalanced

WhitelistedRelayerStatusUpdated

Emitted when relayer whitelist status is updated

event WhitelistedRelayerStatusUpdated(
    address indexed sender, uint32 indexed dstId, address indexed delegate, bool status
);

Parameters

Name	Type	Description
`sender`	`address`	The caller updating whitelist
`dstId`	`uint32`	The destination chain ID
`delegate`	`address`	The relayer address
`status`	`bool`	The whitelist status

Errors

AcrossBridge_TokenMismatch

Error thrown when tokens do not match expected underlying

error AcrossBridge_TokenMismatch();

AcrossBridge_NotAuthorized

Error thrown when caller is not authorized

error AcrossBridge_NotAuthorized();

AcrossBridge_NotImplemented

Error thrown when feature is not implemented

error AcrossBridge_NotImplemented();

AcrossBridge_AddressNotValid

Error thrown when an address is not valid

error AcrossBridge_AddressNotValid();

AcrossBridge_SlippageNotValid

Error thrown when slippage exceeds maximum

error AcrossBridge_SlippageNotValid();

AcrossBridge_RelayerNotValid

Error thrown when relayer is not valid

error AcrossBridge_RelayerNotValid();

AcrossBridge_InvalidReceiver

Error thrown when receiver market is invalid

error AcrossBridge_InvalidReceiver();

AcrossBridge_MaxFeeExceeded

Error thrown when relayer fee exceeds maximum

error AcrossBridge_MaxFeeExceeded();

Structs

DecodedMessage

Decoded Across message payload

struct DecodedMessage {
    address outputToken;
    uint256 inputAmount;
    uint256 outputAmount;
    address relayer;
    uint32 deadline;
    uint32 exclusivityDeadline;
}

Malda