ethereum

README

Exohood Smart Chain

Exohood Smart Chain implementation based on go-ethereum.

Exohood Smart Chain is EVM-compatible, supports all the existing Ethereum tooling, provides nearly instant transaction verification and 1-block finality with a modified version of the Istanbul Byzantine Fault Torerance (IBFT) consensus protocol.

Key Features

IBFT Consensus Protocol

Exohood Smart Chain implements a modified version of the standard IBFT proof of authority consensus protocol, making it the perfect consensus algorithm for public blockchains with a consortium of publicly-known validators participating in the block creation. Existing validators propose and vote to add or remove validators through our on-chain voting system.

This state-of-the-art consensus protocol features:

• Immediate Finality: blocks are final, meaning there are no forks or concurrent alt-chains, and valid blocks must be in the main chain
• Nearly Instant Confirmations: blocks are created every 5 seconds
• Dynamic Validator Set: validators can be added or removed from the network by an on-chain voting mechanism
• Optimal Byzantine Resilience: the protocol can withstand up to (n-1)/3 Byzantine validators, where n is the number of validators

EVM-Compatible

Exohood Smart Chain supports all the existing Ethereum tooling, smart contracts, decentralized applications and regular applications based on the Ethereum JSON RPC, such as MetaMask.

Cross-chain Bridge

Exohood Smart Chain supports cross-chain transfers between our legacy Exohood Blockchain and the Smart Chain. All users, exchanges and other services providers can seemlessly transfer their funds over to the Exohood Smart Chain, free of charge.

Building the source

For prerequisites and detailed build instructions please read the Installation Instructions.

Building exo-sc requires both a Go (version 1.16 or later) and a C compiler. You can install them using your favourite package manager. Once the dependencies are installed, run

make exo-sc

or, to build the full suite of utilities:

make all

Executables

The Exohood-sc project comes with several wrappers/executables found in the cmd directory.

Command	Description
exo-sc	Our main Exohood Smart Chain CLI client. It is the entry point into the Exohood-SC network (main-, test- or private net), capable of running as a full node (default), archive node (retaining all historical state) or a light node (retrieving data live). It can be used by other processes as a gateway into the Exohood-SC network via JSON RPC endpoints exposed on top of HTTP, WebSocket and/or IPC transports. exo-sc --help and the CLI page for command line options.
clef	Stand-alone signing tool, which can be used as a backend signer for exo-sc.
devp2p	Utilities to interact with nodes on the networking layer, without running a full blockchain.
abigen	Source code generator to convert Exohood contract definitions into easy to use, compile-time type-safe Go packages. It operates on plain Ethereum contract ABIs with expanded functionality if the contract bytecode is also available. However, it also accepts Solidity source files, making development much more streamlined. Please see our Native DApps page for details.
bootnode	Stripped down version of our Exohood-SC client implementation that only takes part in the network node discovery protocol, but does not run any of the higher level application protocols. It can be used as a lightweight bootstrap node to aid in finding peers in private networks.
evm	Developer utility version of the EVM (Ethereum Virtual Machine) that is capable of running bytecode snippets within a configurable environment and execution mode. Its purpose is to allow isolated, fine-grained debugging of EVM opcodes (e.g. evm --code 60ff60ff --debug run).
rlpdump	Developer utility tool to convert binary RLP (Recursive Length Prefix) dumps (data encoding used by the Ethereum protocol both network as well as consensus wise) to user-friendlier hierarchical representation (e.g. rlpdump --hex CE0183FFFFFFC4C304050583616263).
puppeth	a CLI wizard that aids in creating a new Exohood-SC network.

Running exo-sc

Going through all the possible command line flags is out of scope here (please consult our CLI Wiki page), but we've enumerated a few common parameter combos to get you up to speed quickly on how you can run your own exo-sc instance.

Hardware Requirements

Minimum:

• CPU with 2+ cores
• 4GB RAM
• 8 MBit/sec download Internet service

Recommended:

• Fast CPU with 4+ cores
• 16GB+ RAM
• High Performance SSD
• 25+ MBit/sec download Internet service

Full node on the main Exohood Smart Chain network

By far the most common scenario is people wanting to simply interact with the Exohood Smart Chain network: create accounts; transfer funds; deploy and interact with contracts. For this particular use-case the user doesn't care about years-old historical data, so we can sync quickly to the current state of the network. To do so:

$ exo-sc console

This command will:

• Start exo-sc in snap sync mode (default, can be changed with the --syncmode flag), causing it to download more data in exchange for avoiding processing the entire history of the Exohood Smart Chain network, which is very CPU intensive.
• Start up exo-sc's built-in interactive JavaScript console, (via the trailing console subcommand) through which you can interact using web3 methods (note: the web3 version bundled within exo-sc is very old, and not up to date with official docs), as well as exo-sc's own management APIs. This tool is optional and if you leave it out you can always attach to an already running exo-sc instance with exo-sc attach.

Full node on the test network

Transitioning towards developers, if you'd like to play around with creating Exohood contracts, you almost certainly would like to do that without any real cryptocurrency involved until you get the hang of the entire system. In other words, instead of attaching to the main network, you want to join the test network with your node, which is fully equivalent to the main network, but with play-exo only.

$ exo-sc --testnet console

The console subcommand has the exact same meaning as above and they are equally useful on the testnet too. Please, see above for their explanations if you've skipped here.

Specifying the --testnet flag, however, will reconfigure your exo-sc instance a bit:

• Instead of connecting the main Exohood Smart Chain network, the client will connect to the test network, which uses different P2P bootnodes, different network IDs and genesis states.
• Instead of using the default data directory (~/.Exohood on Linux for example), exo-sc will nest itself one level deeper into a testnet subfolder (~/.ethereum/testbet on Linux). Note, on OSX and Linux this also means that attaching to a running testnet node requires the use of a custom endpoint since exo-sc attach will try to attach to a production node endpoint by default, e.g., exo-sc attach <datadir>/testnet/exo-sc.ipc. Windows users are not affected by this.

Note: Although there are some internal protective measures to prevent transactions from crossing over between the main network and test network, you should make sure to always use separate accounts for play-cryptocurrency and real-cryptocurrency. Unless you manually move accounts, exo-sc will by default correctly separate the two networks and will not make any accounts available between them.

Configuration

As an alternative to passing the numerous flags to the exo-sc binary, you can also pass a configuration file via:

$ exo-sc --config /path/to/your_config.toml

To get an idea how the file should look like you can use the dumpconfig subcommand to export your existing configuration:

$ exo-sc --your-favourite-flags dumpconfig

Docker quick start

One of the quickest ways to get Exohood Smart Chain up and running on your machine is by using Docker:

docker run -d --name exo-sc-node -v /Users/alice/Exohood:/root \
           -p 8545:8545 -p 30303:30303 \
           Exohood/client-go

This will start exo-sc in snap-sync mode with a DB memory allowance of 1GB just as the above command does. It will also create a persistent volume in your home directory for saving your blockchain as well as map the default ports. There is also an alpine tag available for a slim version of the image.

Do not forget --http.addr 0.0.0.0, if you want to access RPC from other containers and/or hosts. By default, exo-sc binds to the local interface and RPC endpoints are not accessible from the outside.

Programmatically interfacing exo-sc nodes

As a developer, sooner rather than later you'll want to start interacting with exo-sc and the Exohood Smart Chain network via your own programs and not manually through the console. To aid this, exo-sc has built-in support for a JSON-RPC based APIs (standard APIs and exo-sc specific APIs). These can be exposed via HTTP, WebSockets and IPC (UNIX sockets on UNIX based platforms, and named pipes on Windows).

The IPC interface is enabled by default and exposes all the APIs supported by exo-sc, whereas the HTTP and WS interfaces need to manually be enabled and only expose a subset of APIs due to security reasons. These can be turned on/off and configured as you'd expect.

HTTP based JSON-RPC API options:

• --http Enable the HTTP-RPC server
• --http.addr HTTP-RPC server listening interface (default: localhost)
• --http.port HTTP-RPC server listening port (default: 8545)
• --http.api API's offered over the HTTP-RPC interface (default: eth,net,web3)
• --http.corsdomain Comma separated list of domains from which to accept cross origin requests (browser enforced)
• --ws Enable the WS-RPC server
• --ws.addr WS-RPC server listening interface (default: localhost)
• --ws.port WS-RPC server listening port (default: 8546)
• --ws.api API's offered over the WS-RPC interface (default: eth,net,web3)
• --ws.origins Origins from which to accept websockets requests
• --ipcdisable Disable the IPC-RPC server
• --ipcapi API's offered over the IPC-RPC interface (default: admin,debug,eth,miner,net,personal,shh,txpool,web3)
• --ipcpath Filename for IPC socket/pipe within the datadir (explicit paths escape it)

You'll need to use your own programming environments' capabilities (libraries, tools, etc) to connect via HTTP, WS or IPC to a exo-sc node configured with the above flags and you'll need to speak JSON-RPC on all transports. You can reuse the same connection for multiple requests!

Note: Please understand the security implications of opening up an HTTP/WS based transport before doing so! Hackers on the internet are actively trying to subvert Exohood nodes with exposed APIs! Further, all browser tabs can access locally running web servers, so malicious web pages could try to subvert locally available APIs!

Contribution

Thank you for considering to help out with the source code! We welcome contributions from anyone on the internet, and are grateful for even the smallest of fixes!

If you'd like to contribute to Exohood-sc, please fork, fix, commit and send a pull request for the maintainers to review and merge into the main code base. If you wish to submit more complex changes though, please check up with the core devs first on our Discord Server to ensure those changes are in line with the general philosophy of the project and/or get some early feedback which can make both your efforts much lighter as well as our review and merge procedures quick and simple.

Please make sure your contributions adhere to our coding guidelines:

• Code must adhere to the official Go formatting guidelines (i.e. uses gofmt).
• Code must be documented adhering to the official Go commentary guidelines.
• Pull requests need to be based on and opened against the master branch.
• Commit messages should be prefixed with the package(s) they modify.
  • E.g. "eth, rpc: make trace configs optional"

Please see the Developers' Guide for more details on configuring your environment, managing project dependencies, and testing procedures.

License

The Exohood-sc and go-ethereum library (i.e. all code outside of the cmd directory) is licensed under the GNU Lesser General Public License v3.0, also included in our repository in the COPYING.LESSER file.

The Exohood-sc and go-ethereum binaries (i.e. all code inside of the cmd directory) is licensed under the GNU General Public License v3.0, also included in our repository in the COPYING file.

Documentation

Overview

Package ethereum defines interfaces for interacting with Ethereum.

Index

• Variables
• type CallMsg
• type ChainReader
• type ChainStateReader
• type ChainSyncReader
• type ContractCaller
• type FilterQuery
• type GasEstimator
• type GasPricer
• type LogFilterer
• type PendingContractCaller
• type PendingStateEventer
• type PendingStateReader
• type Subscription
• type SyncProgress
• type TransactionReader
• type TransactionSender

Variables

var NotFound = errors.New("not found")

NotFound is returned by API methods if the requested item does not exist.

Types

type CallMsg

type CallMsg struct {
	From      common.Address  // the sender of the 'transaction'
	To        *common.Address // the destination contract (nil for contract creation)
	Gas       uint64          // if 0, the call executes with near-infinite gas
	GasPrice  *big.Int        // wei <-> gas exchange ratio
	GasFeeCap *big.Int        // EIP-1559 fee cap per gas.
	GasTipCap *big.Int        // EIP-1559 tip per gas.
	Value     *big.Int        // amount of wei sent along with the call
	Data      []byte          // input data, usually an ABI-encoded contract method invocation

	AccessList types.AccessList // EIP-2930 access list.
}

CallMsg contains parameters for contract calls.

type ChainReader

type ChainReader interface {
	BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
	BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error)
	HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
	HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
	TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error)
	TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error)

	// This method subscribes to notifications about changes of the head block of
	// the canonical chain.
	SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (Subscription, error)
}

ChainReader provides access to the blockchain. The methods in this interface access raw data from either the canonical chain (when requesting by block number) or any blockchain fork that was previously downloaded and processed by the node. The block number argument can be nil to select the latest canonical block. Reading block headers should be preferred over full blocks whenever possible.

The returned error is NotFound if the requested item does not exist.

type ChainStateReader

type ChainStateReader interface {
	BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error)
	StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error)
	CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
	NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error)
}

ChainStateReader wraps access to the state trie of the canonical blockchain. Note that implementations of the interface may be unable to return state values for old blocks. In many cases, using CallContract can be preferable to reading raw contract storage.

type ChainSyncReader

type ChainSyncReader interface {
	SyncProgress(ctx context.Context) (*SyncProgress, error)
}

ChainSyncReader wraps access to the node's current sync status. If there's no sync currently running, it returns nil.

type ContractCaller

type ContractCaller interface {
	CallContract(ctx context.Context, call CallMsg, blockNumber *big.Int) ([]byte, error)
}

A ContractCaller provides contract calls, essentially transactions that are executed by the EVM but not mined into the blockchain. ContractCall is a low-level method to execute such calls. For applications which are structured around specific contracts, the abigen tool provides a nicer, properly typed way to perform calls.

type FilterQuery

type FilterQuery struct {
	BlockHash *common.Hash     // used by eth_getLogs, return logs only from block with this hash
	FromBlock *big.Int         // beginning of the queried range, nil means genesis block
	ToBlock   *big.Int         // end of the range, nil means latest block
	Addresses []common.Address // restricts matches to events created by specific contracts

	// The Topic list restricts matches to particular event topics. Each event has a list
	// of topics. Topics matches a prefix of that list. An empty element slice matches any
	// topic. Non-empty elements represent an alternative that matches any of the
	// contained topics.
	//
	// Examples:
	// {} or nil          matches any topic list
	// {{A}}              matches topic A in first position
	// {{}, {B}}          matches any topic in first position AND B in second position
	// {{A}, {B}}         matches topic A in first position AND B in second position
	// {{A, B}, {C, D}}   matches topic (A OR B) in first position AND (C OR D) in second position
	Topics [][]common.Hash
}

FilterQuery contains options for contract log filtering.

type GasEstimator

type GasEstimator interface {
	EstimateGas(ctx context.Context, call CallMsg) (uint64, error)
}

GasEstimator wraps EstimateGas, which tries to estimate the gas needed to execute a specific transaction based on the pending state. There is no guarantee that this is the true gas limit requirement as other transactions may be added or removed by miners, but it should provide a basis for setting a reasonable default.

type GasPricer

type GasPricer interface {
	SuggestGasPrice(ctx context.Context) (*big.Int, error)
}

GasPricer wraps the gas price oracle, which monitors the blockchain to determine the optimal gas price given current fee market conditions.

type LogFilterer

type LogFilterer interface {
	FilterLogs(ctx context.Context, q FilterQuery) ([]types.Log, error)
	SubscribeFilterLogs(ctx context.Context, q FilterQuery, ch chan<- types.Log) (Subscription, error)
}

LogFilterer provides access to contract log events using a one-off query or continuous event subscription.

Logs received through a streaming query subscription may have Removed set to true, indicating that the log was reverted due to a chain reorganisation.

type PendingContractCaller

type PendingContractCaller interface {
	PendingCallContract(ctx context.Context, call CallMsg) ([]byte, error)
}

PendingContractCaller can be used to perform calls against the pending state.

type PendingStateEventer

type PendingStateEventer interface {
	SubscribePendingTransactions(ctx context.Context, ch chan<- *types.Transaction) (Subscription, error)
}

A PendingStateEventer provides access to real time notifications about changes to the pending state.

type PendingStateReader

type PendingStateReader interface {
	PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error)
	PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error)
	PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error)
	PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
	PendingTransactionCount(ctx context.Context) (uint, error)
}

A PendingStateReader provides access to the pending state, which is the result of all known executable transactions which have not yet been included in the blockchain. It is commonly used to display the result of ’unconfirmed’ actions (e.g. wallet value transfers) initiated by the user. The PendingNonceAt operation is a good way to retrieve the next available transaction nonce for a specific account.

type Subscription

type Subscription interface {
	// Unsubscribe cancels the sending of events to the data channel
	// and closes the error channel.
	Unsubscribe()
	// Err returns the subscription error channel. The error channel receives
	// a value if there is an issue with the subscription (e.g. the network connection
	// delivering the events has been closed). Only one value will ever be sent.
	// The error channel is closed by Unsubscribe.
	Err() <-chan error
}

Subscription represents an event subscription where events are delivered on a data channel.

type SyncProgress

type SyncProgress struct {
	StartingBlock uint64 // Block number where sync began
	CurrentBlock  uint64 // Current block number where sync is at
	HighestBlock  uint64 // Highest alleged block number in the chain

	// "fast sync" fields. These used to be sent by geth, but are no longer used
	// since version v1.10.
	PulledStates uint64 // Number of state trie entries already downloaded
	KnownStates  uint64 // Total number of state trie entries known about

	// "snap sync" fields.
	SyncedAccounts      uint64 // Number of accounts downloaded
	SyncedAccountBytes  uint64 // Number of account trie bytes persisted to disk
	SyncedBytecodes     uint64 // Number of bytecodes downloaded
	SyncedBytecodeBytes uint64 // Number of bytecode bytes downloaded
	SyncedStorage       uint64 // Number of storage slots downloaded
	SyncedStorageBytes  uint64 // Number of storage trie bytes persisted to disk

	HealedTrienodes     uint64 // Number of state trie nodes downloaded
	HealedTrienodeBytes uint64 // Number of state trie bytes persisted to disk
	HealedBytecodes     uint64 // Number of bytecodes downloaded
	HealedBytecodeBytes uint64 // Number of bytecodes persisted to disk

	HealingTrienodes uint64 // Number of state trie nodes pending
	HealingBytecode  uint64 // Number of bytecodes pending
}

SyncProgress gives progress indications when the node is synchronising with the Ethereum network.

type TransactionReader

type TransactionReader interface {
	// TransactionByHash checks the pool of pending transactions in addition to the
	// blockchain. The isPending return value indicates whether the transaction has been
	// mined yet. Note that the transaction may not be part of the canonical chain even if
	// it's not pending.
	TransactionByHash(ctx context.Context, txHash common.Hash) (tx *types.Transaction, isPending bool, err error)
	// TransactionReceipt returns the receipt of a mined transaction. Note that the
	// transaction may not be included in the current canonical chain even if a receipt
	// exists.
	TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
}

TransactionReader provides access to past transactions and their receipts. Implementations may impose arbitrary restrictions on the transactions and receipts that can be retrieved. Historic transactions may not be available.

Avoid relying on this interface if possible. Contract logs (through the LogFilterer interface) are more reliable and usually safer in the presence of chain reorganisations.

The returned error is NotFound if the requested item does not exist.

type TransactionSender

type TransactionSender interface {
	SendTransaction(ctx context.Context, tx *types.Transaction) error
}

TransactionSender wraps transaction sending. The SendTransaction method injects a signed transaction into the pending transaction pool for execution. If the transaction was a contract creation, the TransactionReceipt method can be used to retrieve the contract address after the transaction has been mined.

The transaction must be signed and have a valid nonce to be included. Consumers of the API can use package accounts to maintain local private keys and need can retrieve the next available nonce using PendingNonceAt.