consensus

Documentation

Overview

Package consensus implements different Ethereum consensus engines.

Package consensus implements different Ethereum consensus engines.

Index

• Variables
• type Broadcaster
• type ChainReader
• type Engine
• type Genesis
• type GenesisAccount
• type GenesisAlloc
• type Handler
• type Istanbul
• type P2PServer
• type Peer
• type PoW

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 its parent's
	// plus one.
	ErrInvalidNumber = errors.New("invalid block number")
)

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(targets map[enode.ID]bool, purpose p2p.PurposeFlag) map[enode.ID]Peer
}

Broadcaster defines the interface to enqueue blocks to fetcher, 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 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)

	// 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)
	// but does not assemble the 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)

	// FinalizeAndAssemble 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).
	FinalizeAndAssemble(chain ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, receipts []*types.Receipt, randomness *types.Randomness) (*types.Block, error)

	// Seal generates a new sealing request for the given input block and pushes
	// the result into the given channel.
	//
	// Note, the method returns immediately and will send the result async. More
	// than one result may also be returned depending on the consensus algorithm.
	Seal(chain ChainReader, block *types.Block, results chan<- *types.Block, stop <-chan struct{}) error

	// SealHash returns the hash of a block prior to it being sealed.
	SealHash(header *types.Header) common.Hash

	// GetValidators returns the list of current validators.
	GetValidators(blockNumber *big.Int, headerHash common.Hash) []istanbul.Validator

	EpochSize() uint64

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

	// Close terminates any background threads maintained by the consensus engine.
	Close() error
}

Engine is an algorithm agnostic consensus engine.

type Genesis

type Genesis interface {
	GetAlloc() GenesisAlloc

	UnmarshalFromDB(db ethdb.Database) error
}

type GenesisAccount

type GenesisAccount interface {
	GetPublicKey() []byte
}

type GenesisAlloc

type GenesisAlloc map[common.Address]GenesisAccount

type Handler

type Handler interface {
	// NewWork handles a new work event from the miner
	NewWork() error

	// NewChainHead handles a new head block
	NewChainHead(*types.Block)

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

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

	// SetP2PServer sets the p2p server to connect/disconnect to/from peers
	SetP2PServer(P2PServer)

	// RegisterPeer will notify the consensus engine that a new peer has been added
	RegisterPeer(peer Peer, fromProxiedNode bool)

	// UnregisterPeer will notify the consensus engine that a new peer has been removed
	UnregisterPeer(peer Peer, fromProxiedNode bool)

	// Handshake will begin a handshake with a new peer. It returns if the peer
	// has identified itself as a validator and should bypass any max peer checks.
	Handshake(peer Peer) (bool, error)
}

Handler should be implemented if the consensus needs to handle and send peer messages

type Istanbul

type Istanbul interface {
	Engine

	// SetChain injects the blockchain and related functions to the istanbul consensus engine
	SetChain(chain ChainReader, currentBlock func() *types.Block, stateAt func(common.Hash) (*state.StateDB, error))

	// StartValidating starts the validating engine
	StartValidating(hasBadBlock func(common.Hash) bool,
		processBlock func(*types.Block, *state.StateDB) (types.Receipts, []*types.Log, uint64, error),
		validateState func(*types.Block, *state.StateDB, types.Receipts, uint64) error) error

	// StopValidating stops the validating engine
	StopValidating() error

	// StartAnnouncing starts the announcing
	StartAnnouncing() error

	// StopAnnouncing stops the announcing
	StopAnnouncing() error

	// This is only implemented for Istanbul.
	// It will update the validator set diff in the header, if the mined header is the last block of the epoch.
	// The changes are executed inline.
	UpdateValSetDiff(chain ChainReader, header *types.Header, state *state.StateDB) error

	// This is only implemented for Istanbul.
	// It will check to see if the header is from the last block of an epoch
	IsLastBlockOfEpoch(header *types.Header) bool
}

Istanbul is a consensus engine to avoid byzantine failure

type P2PServer

type P2PServer interface {
	// Gets this node's enode
	Self() *enode.Node
	// AddPeer will add a peer to the p2p server instance
	AddPeer(node *enode.Node, purpose p2p.PurposeFlag)
	// RemovePeer will remove a peer from the p2p server instance
	RemovePeer(node *enode.Node, purpose p2p.PurposeFlag)
	// AddTrustedPeer will add a trusted peer to the p2p server instance
	AddTrustedPeer(node *enode.Node, purpose p2p.PurposeFlag)
	// RemoveTrustedPeer will remove a trusted peer from the p2p server instance
	RemoveTrustedPeer(node *enode.Node, purpose p2p.PurposeFlag)
}

P2PServer defines the interface for a p2p.server to get the local node's enode and to add/remove for static/trusted peers

type Peer

type Peer interface {
	// Send sends the message to this peer
	Send(msgcode uint64, data interface{}) error
	// Node returns the peer's enode
	Node() *enode.Node
	// Version returns the peer's version
	Version() int
	// Blocks until a message is read directly from the peer.
	// This should only be used during a handshake.
	ReadMsg() (p2p.Msg, error)
	// Inbound returns if the peer connection is inbound
	Inbound() bool
	// PurposeIsSet returns if the peer has a purpose set
	PurposeIsSet(purpose p2p.PurposeFlag) bool
}

Peer defines the interface for a p2p.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.