Bridge Program

Abstract

In this repository you will find the bridge program on the Solana side for MultiversX <-> Solana bridge. The main purpose is to allow users to deposit and lock tokens inside the program liquidity. The relayer service is responsible for the transfer of the tokens between the two blockchains, using bridge liquidity smart contracts on both sides.

Overview

The bridge program can be directly controlled by an administrator account. The administrator account can perform the following actions:

• Initialize the contract
• Change fee amount
• Change the deposit limits
• Activate/deactivate the program
• Change the relayer address
• Change the whitelisted token
• Activate/Deactivate a user whitelist
• Add/Remove a user from the whitelist
• Add/Remove liquidity

The administrator account is a constant address defined in the constants.rs file. There are some workarounds or other solutions to restrict the access of an endpoint to the administrator account, but are more error-prone, so we decided to use a simple solution, a constant address.

The whitelisted relayer address which is stored in the bridge state account is used to restrict the sendFromLiquidity endpoint to the relayer address.

Folder structure

• programs - contains the bridge program
• src - contains all the source code
• src/contexts - contains the program contexts for each endpoint
• src/states - contains the program states accounts
• src/constants - contains the program constants
• src/errors - contains the program custom errors
• src/lib - contains the program endpoints

Install, Build, Deploy and Test

Let's run the test once to see what happens.

Install anchor

First, make sure that anchor is installed:

Install avm:

$ cargo install --git https://github.com/coral-xyz/anchor avm --locked --force
...

Install latest anchor version:

$ avm install 0.29.0
...
$ avm use 0.29.0
...

Verify the Installation

Check if Anchor is successfully installed:

$ anchor --version
anchor-cli 0.29.0

Install Dependencies

Next, install dependencies:

$ yarn

Build bridge-program

Update program_id

Get the public key of the deploy key. This keypair is generated automatically so a different key is exptected:

$ anchor keys list
bridge-program: DRxp3EJv4hGQDze6Evf515KE1YwVgYNv6PiDp1dqF4pK

Replace the default value of program_id with this new value:

# Anchor.toml

[programs.localnet]
bridge_program = "DRxp3EJv4hGQDze6Evf515KE1YwVgYNv6PiDp1dqF4pK"

...

// lib.rs

...

declare_id!("DRxp3EJv4hGQDze6Evf515KE1YwVgYNv6PiDp1dqF4pK");

...

Build the program:

$ anchor build

Deploy bridge-program

Let's deploy the program.

$ solana config set --url localhost

$ anchor deploy


Program Id: DRxp3EJv4hGQDze6Evf515KE1YwVgYNv6PiDp1dqF4pK

Deploy success

Test bridge-program

To test against localnet, update the cluster section in Anchor.toml:

[provider]
cluster = "localnet"

Because the program needs a constant admin address, the tests will use the UNIT_TEST_PRIVATE_KEY stored in the .env file. This key is used to sign transactions in the tests. Copy the content from env.copy to .env. Copy the UNIT_TEST_PUBLIC_KEY from the env.copy to the constants.rs file where the ADMIN_PUBKEY constant is defined.

$ anchor test

Admin CLI for bridge-program

The admin CLI is a simple rust CLI that can be used to interact with the program admin endpoints. It is located in the interactions directory.

To run the CLI, first build it:

cargo run

Run help for the complete list of options:

cargo run -- --help

admin-bridge-cli 0.1.0

USAGE:
    admin-bridge-cli [OPTIONS] <SUBCOMMAND>

OPTIONS:
    -C, --config <PATH>        Configuration file to use [default:
                               /Users/<user>/.config/solana/cli/config.yml]
    -h, --help                 Print help information
        --keypair <KEYPAIR>    Filepath or URL to a keypair [default: client keypair]
    -u, --url <URL>            JSON RPC URL for the cluster [default: value from configuration file]
    -v, --verbose              Show additional information
    -V, --version              Print version information

SUBCOMMANDS:
    addLiquidity             Send an add liquidity transaction
    addToWhitelist           Send an add to whitelist transaction
    help                     Print this message or the help of the given subcommand(s)
    initializeContract       Send an initialize contract transaction
    pause                    Send a pause transaction
    removeFromWhitelist      Send a remove from whitelist transaction
    removeLiquidity          Send a remove liquidity transaction
    setDepositLimits         Send a set deposit limits transaction
    setWhitelistActive       Send a set whitelist active transaction
    setWhitelistInactive     Send a set whitelist inactive transaction
    unpause                  Send a unpause transaction
    updateRelayer            Send an update relayer transaction
    updateWhitelistedMint    Send a update whitelisted mint transaction

Example:

cargo run -- pause --url https://api.devnet.solana.com --keypair "usb://ledger?key=0"

To sign and send a transaction using ledger Nano S, do the following:

1. Allow blind signing in the ledger settings.
2. Pubkey length set to Long in the ledger settings.