Chainlink CCIP Smart Contracts

[!IMPORTANT] Since v1.6.0 of the CCIP contracts, the contracts have been moved to a new repository: chainlink-ccip. The EVM contracts exist in the chains/evm directory of the repository.

Installation

Chainlink-ccip relies on chainlink-evm, below are the instructions to install both. To find the correct version of chainlink-evm to use for any given version of chainlink-ccip, please refer to the package.json file in /chains/evm. It contains an NPM dependency on @chainlink/contracts with the correct version for the given version of chainlink-ccip.

NOTE: while other versions of chainlink-evm may work, we only test against the version specified in the package.json file. Audits are also only done against the version specified in the package.json file. No guarantees are made for other versions.

Foundry (git)

[!WARNING] When installing via git, the ref defaults to master when no tag is given.

When installing through git, it is recommended to use a specific version tag to avoid breaking changes. The corresponding git tag will be contracts-ccip-v<version> for chainlink-ccip, and contracts-v<version> for chainlink-evm.

forge install smartcontractkit/[email protected]
forge install smartcontractkit/[email protected]
forge install foundry-rs/[email protected]

CCIP contracts also depend on OpenZeppelin and Chainlink ACE packages that are distributed via npm. Install the versions listed in package.json for the CCIP release you are using:

pnpm add @chainlink/[email protected]
pnpm add @openzeppelin/contracts-4.8.3@npm:@openzeppelin/[email protected]
pnpm add @openzeppelin/contracts-5.3.0@npm:@openzeppelin/[email protected]

Add the following remappings to remappings.txt:

forge-std/=lib/forge-std/src/
@chainlink/contracts/=lib/chainlink-evm/contracts/
@chainlink/contracts-ccip/contracts/=lib/chainlink-ccip/chains/evm/contracts/
@chainlink/policy-management/=node_modules/@chainlink/ace/packages/policy-management/src/
@openzeppelin/[email protected]=node_modules/@openzeppelin/contracts-4.8.3
@openzeppelin/[email protected]=node_modules/@openzeppelin/contracts-5.3.0

(P)NPM

# pnpm
pnpm add @chainlink/[email protected]
pnpm add @chainlink/[email protected]
pnpm add @chainlink/[email protected]
pnpm add @openzeppelin/contracts-4.8.3@npm:@openzeppelin/[email protected]
pnpm add @openzeppelin/contracts-5.3.0@npm:@openzeppelin/[email protected]

# npm
npm install @chainlink/[email protected] --save
npm install @chainlink/[email protected] --save
npm install @chainlink/[email protected] --save
npm install @openzeppelin/contracts-4.8.3@npm:@openzeppelin/[email protected] --save
npm install @openzeppelin/contracts-5.3.0@npm:@openzeppelin/[email protected] --save

Add the following remappings to remappings.txt:

@chainlink/contracts/=node_modules/@chainlink/contracts/
@chainlink/contracts-ccip/contracts/=node_modules/@chainlink/contracts-ccip/contracts/
@chainlink/policy-management/=node_modules/@chainlink/ace/packages/policy-management/src/
@openzeppelin/[email protected]=node_modules/@openzeppelin/contracts-4.8.3
@openzeppelin/[email protected]=node_modules/@openzeppelin/contracts-5.3.0

Directory Structure

@chainlink/contracts-ccip
├── contracts # Solidity contracts
├── scripts # Compilation script
└── abi # ABI json output

Usage

[!WARNING] Contracts in dev/ directories or with a typeAndVersion ending in -dev are under active development and are likely unaudited. Please refrain from using these in production applications.

The contracts can be imported via @chainlink/contracts-ccip/contracts:

import {CCIPReceiver} from '@chainlink/contracts-ccip/contracts/applications/CCIPReceiver.sol';

Getting started with CCIP

To get started with CCIP, please refer to the CCIP documentation.

The MockRouter contract is a good starting point when developing dapps that use CCIP. It is a simplified same-chain entry and exit point for CCIP messages. It lives in contracts/test/mocks/MockRouter.sol.

Remapping

This repository uses Solidity remappings to resolve imports.

The remappings.txt file in this directory contains the remappings used when developing CCIP itself via npm. When consuming CCIP in another project, use the remappings from the Installation section above, which additionally include the @chainlink/contracts-ccip/contracts/ prefix.

CCIP contracts import versioned OpenZeppelin packages using aliases such as @openzeppelin/[email protected]. The remappings above map those aliases to the corresponding npm package directories (for example, @openzeppelin/contracts-5.3.0). This allows you to use a wide range of versions of Openzeppelin in your project without conflicts.

Changesets

We use changesets to manage versioning the contracts.

Every PR that modifies any configuration or code, should most likely accompanied by a changeset file.

To install changesets:

1. Install pnpm if it is not already installed - docs.
2. Run pnpm install.

Either after or before you create a commit, run the pnpm changeset command in the chains/evm directory to create an accompanying changeset entry which will reflect on the CHANGELOG for the next release.

The format is based on Keep a Changelog and this project adheres to Semantic Versioning.

License

The CCIP contracts are licensed under the BUSL-1.1 license. See v2.0-CCIP-License-grants for additional use grants.