> For the complete documentation index, see [llms.txt](https://docs.rigoblock.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.rigoblock.com/solidity-api-reference/protocol/extensions/ecrosschain.md).

# ECrosschain

## ECrosschain

This extension manages NAV integrity when receiving tokens from cross-chain sources.

*Called via delegatecall from pool. Can be called by Across messages, Escrow contracts, or anyone with tokens to donate. Direct calls will fail naturally because the contract does not implement `updateUnitaryValue`.*

### CallerTransferAmount

```solidity
error CallerTransferAmount()
```

### donate

```solidity
function donate(address token, uint256 amount, struct DestinationMessageParams params) external
```

Handles receiving tokens from a cross-chain message or an escrow refund.

*Called via delegatecall from pool. Callable by anyone.*

#### Parameters

| Name   | Type                            | Description                                                                    |
| ------ | ------------------------------- | ------------------------------------------------------------------------------ |
| token  | address                         | The token received on this chain.                                              |
| amount | uint256                         | The amount received.                                                           |
| params | struct DestinationMessageParams | The message params from the source calls sent to the across multicall handler. |