consensus

Documentation

Overview

Package consensus implements different Ethereum consensus engines.

Package consensus implements different Ethereum consensus engines.

Index

• Constants
• Variables
• type Broadcaster
• type ChainReader
• type Engine
• type Handler
• type Istanbul
• type Peer
• type PoW
• type Protocol

Constants

const (
	Eth62 = 62
	Eth63 = 63
)

Constants to match up protocol versions and messages

Variables

var (
	// ErrUnknownAncestor is returned when validating a block requires an ancestor
	// that is unknown.
	ErrUnknownAncestor = errors.New("unknown ancestor")

	// ErrPrunedAncestor is returned when validating a block requires an ancestor
	// that is known, but the state of which is not available.
	ErrPrunedAncestor = errors.New("pruned ancestor")

	// ErrFutureBlock is returned when a block's timestamp is in the future according
	// to the current node.
	ErrFutureBlock = errors.New("block in the future")

	// ErrInvalidNumber is returned if a block's number doesn't equal it's parent's
	// plus one.
	ErrInvalidNumber = errors.New("invalid block number")
)

var (
	EthProtocol = Protocol{
		Name:     "eth",
		Versions: []uint{Eth62, Eth63},
		Lengths:  []uint64{17, 8},
	}
)

Types

type Broadcaster

type Broadcaster interface {
	// Enqueue add a block into fetcher queue
	Enqueue(id string, block *types.Block)
	// FindPeers retrives peers by addresses
	FindPeers(map[common.Address]bool) map[common.Address]Peer
}

Broadcaster defines the interface to enqueue blocks to fetcher and find peer

type ChainReader

type ChainReader interface {
	// Config retrieves the blockchain's chain configuration.
	Config() *params.ChainConfig

	// CurrentHeader retrieves the current header from the local chain.
	CurrentHeader() *types.Header

	// GetHeader retrieves a block header from the database by hash and number.
	GetHeader(hash common.Hash, number uint64) *types.Header

	// GetHeaderByNumber retrieves a block header from the database by number.
	GetHeaderByNumber(number uint64) *types.Header

	// GetHeaderByHash retrieves a block header from the database by its hash.
	GetHeaderByHash(hash common.Hash) *types.Header

	// GetBlock retrieves a block from the database by hash and number.
	GetBlock(hash common.Hash, number uint64) *types.Block
}

ChainReader defines a small collection of methods needed to access the local blockchain during header and/or uncle verification.

type Engine

type Engine interface {
	// Author retrieves the Ethereum address of the account that minted the given
	// block, which may be different from the header's coinbase if a consensus
	// engine is based on signatures.
	Author(header *types.Header) (common.Address, error)

	// VerifyHeader checks whether a header conforms to the consensus rules of a
	// given engine. Verifying the seal may be done optionally here, or explicitly
	// via the VerifySeal method.
	VerifyHeader(chain ChainReader, header *types.Header, seal bool) error

	// VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers
	// concurrently. The method returns a quit channel to abort the operations and
	// a results channel to retrieve the async verifications (the order is that of
	// the input slice).
	VerifyHeaders(chain ChainReader, headers []*types.Header, seals []bool) (chan<- struct{}, <-chan error)

	// VerifyUncles verifies that the given block's uncles conform to the consensus
	// rules of a given engine.
	VerifyUncles(chain ChainReader, block *types.Block) error

	// VerifySeal checks whether the crypto seal on a header is valid according to
	// the consensus rules of the given engine.
	VerifySeal(chain ChainReader, header *types.Header) error

	// Prepare initializes the consensus fields of a block header according to the
	// rules of a particular engine. The changes are executed inline.
	Prepare(chain ChainReader, header *types.Header) error

	// Finalize runs any post-transaction state modifications (e.g. block rewards)
	// and assembles the final block.
	// Note: The block header and state database might be updated to reflect any
	// consensus rules that happen at finalization (e.g. block rewards).
	Finalize(chain ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction,
		uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error)

	// Seal generates a new block for the given input block with the local miner's
	// seal place on top.
	Seal(chain ChainReader, block *types.Block, stop <-chan struct{}) (*types.Block, error)

	// CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
	// that a new block should have.
	CalcDifficulty(chain ChainReader, time uint64, parent *types.Header) *big.Int

	// APIs returns the RPC APIs this consensus engine provides.
	APIs(chain ChainReader) []rpc.API

	// Protocol returns the protocol for this consensus
	Protocol() Protocol
}

Engine is an algorithm agnostic consensus engine.

type Handler

type Handler interface {
	// NewChainHead handles a new head block comes
	NewChainHead() error

	// HandleMsg handles a message from peer
	HandleMsg(address common.Address, data p2p.Msg) (bool, error)

	// SetBroadcaster sets the broadcaster to send message to peers
	SetBroadcaster(Broadcaster)
}

Handler should be implemented is the consensus needs to handle and send peer's message

type Istanbul

type Istanbul interface {
	Engine

	// Start starts the engine
	Start(chain ChainReader, currentBlock func() *types.Block, hasBadBlock func(hash common.Hash) bool) error

	// Stop stops the engine
	Stop() error
}

Istanbul is a consensus engine to avoid byzantine failure

type Peer

type Peer interface {
	// Send sends the message to this peer
	Send(msgcode uint64, data interface{}) error
}

Peer defines the interface to communicate with peer

type PoW

type PoW interface {
	Engine

	// Hashrate returns the current mining hashrate of a PoW consensus engine.
	Hashrate() float64
}

PoW is a consensus engine based on proof-of-work.

type Protocol

type Protocol struct {
	// Official short name of the protocol used during capability negotiation.
	Name string
	// Supported versions of the eth protocol (first is primary).
	Versions []uint
	// Number of implemented message corresponding to different protocol versions.
	Lengths []uint64
}

Protocol defines the protocol of the consensus