smom-dbis-138/docs/operations/integrations/CCIP_INTEGRATION.md

CCIP Integration Guide

Overview

Chainlink Cross-Chain Interoperability Protocol (CCIP) enables secure cross-chain communication for oracle data updates. This guide explains how to integrate CCIP with the DeFi Oracle Meta Mainnet.

Architecture

┌─────────────────┐         ┌──────────────┐         ┌─────────────────┐
│  Source Chain   │────────▶│  CCIP Router │────────▶│  Target Chain   │
│  (ChainID 138)  │         │              │         │  (Other Chain)  │
└─────────────────┘         └──────────────┘         └─────────────────┘
       │                            │                          │
       │                            │                          │
       ▼                            ▼                          ▼
┌──────────────┐         ┌──────────────┐         ┌──────────────┐
│ CCIPSender   │         │ CCIP Router  │         │ CCIPReceiver │
│  Contract    │         │   Service    │         │   Contract   │
└──────────────┘         └──────────────┘         └──────────────┘

Components

1. CCIP Router Interface

The IRouterClient interface defines the standard CCIP Router interface for sending and receiving cross-chain messages.

Location: contracts/ccip/IRouterClient.sol

2. CCIP Sender Contract

The CCIPSender contract sends oracle data to other chains via CCIP.

Location: contracts/ccip/CCIPSender.sol

Key Functions:

• sendOracleUpdate(): Sends oracle price update to target chain
• calculateFee(): Calculates CCIP message fee

3. CCIP Receiver Contract

The CCIPReceiver contract receives oracle data from other chains via CCIP.

Location: contracts/ccip/CCIPReceiver.sol

Key Functions:

• ccipReceive(): Handles incoming CCIP messages
• updateOracle(): Updates oracle aggregator with received data

Integration Steps

Step 1: Deploy CCIP Router

1. Deploy Chainlink CCIP Router on your chain
2. Get the router address
3. Configure router in your contracts

Step 2: Deploy CCIP Contracts

# Deploy CCIPSender
forge script script/DeployCCIPSender.s.sol --rpc-url $RPC_URL --broadcast

# Deploy CCIPReceiver
forge script script/DeployCCIPReceiver.s.sol --rpc-url $RPC_URL --broadcast

Step 3: Configure Contracts

1. Set CCIP Router address in sender and receiver contracts
2. Set target chain selector
3. Configure oracle aggregator address
4. Set transmitter role for receiver contract

Step 4: Send Cross-Chain Messages

// In your oracle update function
CCIPSender sender = CCIPSender(senderAddress);
uint256 fee = sender.calculateFee(targetChainSelector, messageData);
sender.sendOracleUpdate{value: fee}(targetChainSelector, receiverAddress, priceData);

Step 5: Receive Cross-Chain Messages

The CCIP Router automatically calls ccipReceive() on the receiver contract when a message arrives.

Message Format

CCIP messages contain encoded oracle data:

struct OracleMessage {
    uint256 answer;      // Oracle price/answer
    uint256 roundId;     // Round ID
    uint256 timestamp;   // Timestamp
}

Fee Calculation

CCIP fees are calculated based on:

• Message size
• Target chain
• Gas price on target chain

Use calculateFee() to get the required fee before sending.

Security Considerations

1. Replay Protection: Messages are tracked by messageId to prevent replay attacks
2. Access Control: Only authorized transmitters can update oracles
3. Message Validation: Validate message format and source chain
4. Fee Management: Ensure sufficient LINK tokens for fees

Monitoring

Monitor CCIP message flow:

• Message send success/failure rates
• Message delivery latency
• Fee consumption
• Error rates

See monitoring/prometheus/alerts/ccip.yml for alerting rules.

Troubleshooting

Message Not Received

1. Check CCIP Router is deployed and running
2. Verify target chain selector is correct
3. Check receiver contract address is correct
4. Verify sufficient LINK tokens for fees
5. Check message was sent successfully

High Fees

1. Optimize message size
2. Consider batching multiple updates
3. Monitor gas prices on target chain

Replay Protection Errors

1. Check processedMessages mapping
2. Verify message IDs are unique
3. Check for duplicate message sends

References

• Chainlink CCIP Documentation
• CCIP Router Setup Guide
• CCIP Message Format
• CCIP Fees