Proxy Airdrop Contracts

This repository contains two different implementations of proxy airdrop contracts.

Contract Options

1. ProxySponsor_OPTION1 (Simplified)

File: contracts/ProxySponsor_OPTION1.sol

A streamlined proxy contract focused solely on efficient airdrop operations without additional complexity.

Features:

• ✅ Smart Airdrop Logic - Prevents over-funding by checking receiver balance
• ✅ Gas Cost Calculation - Dynamic gas cost calculation for optimal transfers adding approve and stake txs
• ✅ Gas Cost Coefficient - Configurable multiplier for gas cost calculations (default: 105%)
• ✅ Minimum Transfer Value - Configurable minimum airdrop amounts

Constructor Parameters:

constructor(address _dedicatedMsgSender)

---

2. ProxySponsor (Full Featured)

File: contracts/ProxySponsor.sol

A comprehensive proxy contract with advanced features including gasless transactions and staking capabilities.

Features:

• ✅ Smart Airdrop Logic - Prevents over-funding by checking receiver balance
• ✅ Gas Cost Calculation - Dynamic gas cost calculation for optimal transfers only considering approve
• ✅ Gas Cost Coefficient - Configurable multiplier for gas cost calculations (default: 105%)
• ✅ Minimum Transfer Value - Configurable minimum airdrop amounts
• ✅ Gasless USDC Staking - Integration with external USDC staking contracts
• ✅ Gasless ETH Staking - Integration with external ETH staking contracts

Constructor Parameters:

constructor(
    address _dedicatedMsgSender,
    address _trustedForwarder,
    address _stakeContractUSDC,
    address _stakeContractETH
)

---

Technical Architecture

State Variables

Both contracts maintain:

• owner - Contract administrator
• dedicatedMsgSender - Authorized airdrop caller
• minimumTransferValue - Minimum ETH transfer amount
• gasCostCoefficient - Gas cost multiplier in basis points (default: 10500 = 105%)
• gasApprove - Gas units for approve operation (default: 40000)

ProxySponsor_OPTION1 Additional:

• gasStake - Gas units for stake operation (default: 140000)

Core Airdrop Functionality

function airdrop(address receiver, uint256 gasPrice) external onlyDedicatedMsgSender

• Transfers ETH to receiver based on provided gas price and gas costs or minimum value
• Prevents over-funding by checking receiver's current balance
• Only callable by the dedicated message sender
• Validates that gas price is not zero

Admin Functions

function setMinimumTransferValue(uint256 _minimumValue) external onlyOwner
function setGasCostCoefficient(uint256 _coefficient) external onlyOwner
function setGasApprove(uint256 _gasApprove) external onlyOwner
function changeDedicatedMsgSender(address _newDedicatedMsgSender) external onlyOwner
function changeOwner(address _newOwner) external onlyOwner
function withdraw() external onlyOwner

ProxySponsor_OPTION1 Additional:

function setGasStake(uint256 _gasStake) external onlyOwner

Setup and Testing

Installation

npm install

Compilation

npx hardhat compile

Testing

# Test both contracts
npx hardhat test --network hardhat

# Test specific contract
npx hardhat test test/proxy-sponsor.ts --network hardhat
npx hardhat test test/proxy-sponsor-option1.ts --network hardhat

Test Coverage

• ProxySponsor_OPTION1: 36 tests covering core functionality
• ProxySponsor_OPTION2: 42 tests covering all features

Security Considerations

Both Contracts

• ✅ Access Control - Proper modifier usage
• ✅ Reentrancy Protection - No external calls in critical functions
• ✅ Input Validation - Comprehensive parameter checks
• ✅ Custom Errors - Gas-efficient error handling

ProxySponsor_OPTION2 Additional

• ✅ ERC2771 Security - Trusted forwarder validation
• ✅ Staking Integration - External contract validation
• ✅ Advanced Admin - Stake contract management

License

MIT