ZetaChain Gateway Router

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Key Features

• Cross-chain message parsing
• Multi-DEX integration (Algebra & UniswapV2)
• Native token wrapping/unwrapping
• Gas fee management for cross-chain transactions
• Blacklist protection

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Architecture Overview

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Core Functions

    //function designed to be called automatically by zeta observers
    function onCall(
        zContext calldata context,
        address fromToken,
        uint256 amount,
        bytes calldata message
    ) external virtual;

    //functions to be called by eoa wallets to leave zetachain
    function fromZetaCrosschain(
        address fromToken,
        address toToken,
        bytes calldata path,
        uint256 inputAmount,
        uint256 minAmountOut,
        bytes calldata receiver
    ) external virtual;

    function fromZetaNativeCrosschain(
        address wzeta,
        address toToken,
        bytes calldata path,
        uint256 inputAmount,
        uint256 minAmountOut,
        bytes calldata receiver
    ) external virtual payable;

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Message Structure

The cross-chain messages follow a specific structure parsed by the MessageParserLib:

{
  toToken: string // Destination token address
  receiver: bytes // Recipient address bytes
  path: bytes // Swap path for routing
  withdraw: boolean // Whether to withdraw from ZetaChain
  minAmountOut: uint256 // Minimum amount to receive
}

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Security Features

1. Token Blacklisting

   • Contract maintains a blacklist of tokens
   • Owner can update blacklist entries
   • Prevents swaps with malicious tokens

2. Slippage Protection

   • Enforces minimum output amounts
   • Handles gas token swaps with 4% slippage tolerance

3. Deadline Checks

   • All swaps expire after 600 seconds
   • Prevents pending transactions from executing at unfavorable rates

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Integration Points

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1. DEX Integration

The router integrates with two types of DEXes:

• Algebra (concentrated liquidity)
• UniswapV2 (constant product)

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2. Token Standards

Supports multiple token types:

• Native ZetaChain token (ZETA)
• Wrapped ZETA (WZETA)
• ZRC20 tokens
• Cross-chain assets

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3. Gas Management

To ensure we always have the necessary liquidity required for the bridge token we leverage uniswap v2 style pools offered by zetachain

if (params.withdraw && params.toToken != gasZRC20) {
    // Gas token swap logic
    address[] memory path = UniswapV2Library.getUniswapV2Path(
        params.toToken,
        gasZRC20,
        wzeta
    );
    uint256[] memory amountsQuote = UniswapV2Library.getAmountsIn(
        gasFee,
        path
    );
    uint256 amountInMax = amountsQuote[0] + amountsQuote[0] / 25;
}

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Best Practices

1. Gas Optimization

   • Use direct pool swaps when possible
   • Optimize path encoding for Bitcoin transactions
   • Batch operations where feasible

2. Error Handling

   • Implement comprehensive revert messages
   • Handle edge cases for token transfers
   • Validate input parameters

3. Security Considerations

   • Always verify token approvals
   • Check pool existence before swaps
   • Validate recipient addresses

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Maintenance

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Owner Functions

1. Token Management

function updateBlacklist(address contractAddress, bool flag) public onlyOwner
function sweepToken(address receiver, address token) public onlyOwner

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Emergency Procedures

1. Token Recovery
   • Owner can sweep stuck tokens
   • Requires valid token and receiver addresses
   • Verifies transfer success

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Considerations

1. Cross-Chain Testing

   • Test with various source chains
   • Verify message parsing
   • Validate gas fee calculations

2. Pool Integration

   • Test direct vs multi-hop swaps
   • Verify pool existence checks
   • Validate slippage protection

3. Edge Cases

   • Zero amount transfers
   • Invalid token addresses
   • Insufficient gas token amounts