snap

package
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Published: Apr 1, 2021 License: GPL-3.0 Imports: 25 Imported by: 0

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Index

Constants

View Source
const (
	GetAccountRangeMsg  = 0x00
	AccountRangeMsg     = 0x01
	GetStorageRangesMsg = 0x02
	StorageRangesMsg    = 0x03
	GetByteCodesMsg     = 0x04
	ByteCodesMsg        = 0x05
	GetTrieNodesMsg     = 0x06
	TrieNodesMsg        = 0x07
)
View Source
const ProtocolName = "snap"

ProtocolName is the official short name of the `snap` protocol used during devp2p capability negotiation.

Variables

View Source
var ErrCancelled = errors.New("sync cancelled")

ErrCancelled is returned from snap syncing if the operation was prematurely terminated.

View Source
var ProtocolVersions = []uint{snap1}

ProtocolVersions are the supported versions of the `snap` protocol (first is primary).

Functions

func MakeProtocols

func MakeProtocols(backend Backend, dnsdisc enode.Iterator) []p2p.Protocol

MakeProtocols constructs the P2P protocol definitions for `snap`.

Types

type AccountData

type AccountData struct {
	Hash common.Hash  // Hash of the account
	Body rlp.RawValue // Account body in slim format
}

AccountData represents a single account in a query response.

type AccountRangePacket

type AccountRangePacket struct {
	ID       uint64         // ID of the request this is a response for
	Accounts []*AccountData // List of consecutive accounts from the trie
	Proof    [][]byte       // List of trie nodes proving the account range
}

AccountRangePacket represents an account query response.

func (*AccountRangePacket) Kind

func (*AccountRangePacket) Kind() byte

func (*AccountRangePacket) Name

func (*AccountRangePacket) Name() string

func (*AccountRangePacket) Unpack

func (p *AccountRangePacket) Unpack() ([]common.Hash, [][]byte, error)

Unpack retrieves the accounts from the range packet and converts from slim wire representation to consensus format. The returned data is RLP encoded since it's expected to be serialized to disk without further interpretation.

Note, this method does a round of RLP decoding and reencoding, so only use it once and cache the results if need be. Ideally discard the packet afterwards to not double the memory use.

type Backend

type Backend interface {
	// Chain retrieves the blockchain object to serve data.
	Chain() *core.BlockChain

	// RunPeer is invoked when a peer joins on the `eth` protocol. The handler
	// should do any peer maintenance work, handshakes and validations. If all
	// is passed, control should be given back to the `handler` to process the
	// inbound messages going forward.
	RunPeer(peer *Peer, handler Handler) error

	// PeerInfo retrieves all known `snap` information about a peer.
	PeerInfo(id enode.ID) interface{}

	// Handle is a callback to be invoked when a data packet is received from
	// the remote peer. Only packets not consumed by the protocol handler will
	// be forwarded to the backend.
	Handle(peer *Peer, packet Packet) error
}

Backend defines the data retrieval methods to serve remote requests and the callback methods to invoke on remote deliveries.

type ByteCodesPacket

type ByteCodesPacket struct {
	ID    uint64   // ID of the request this is a response for
	Codes [][]byte // Requested contract bytecodes
}

ByteCodesPacket represents a contract bytecode query response.

func (*ByteCodesPacket) Kind

func (*ByteCodesPacket) Kind() byte

func (*ByteCodesPacket) Name

func (*ByteCodesPacket) Name() string

type GetAccountRangePacket

type GetAccountRangePacket struct {
	ID     uint64      // Request ID to match up responses with
	Root   common.Hash // Root hash of the account trie to serve
	Origin common.Hash // Hash of the first account to retrieve
	Limit  common.Hash // Hash of the last account to retrieve
	Bytes  uint64      // Soft limit at which to stop returning data
}

GetAccountRangePacket represents an account query.

func (*GetAccountRangePacket) Kind

func (*GetAccountRangePacket) Kind() byte

func (*GetAccountRangePacket) Name

func (*GetAccountRangePacket) Name() string

type GetByteCodesPacket

type GetByteCodesPacket struct {
	ID     uint64        // Request ID to match up responses with
	Hashes []common.Hash // Code hashes to retrieve the code for
	Bytes  uint64        // Soft limit at which to stop returning data
}

GetByteCodesPacket represents a contract bytecode query.

func (*GetByteCodesPacket) Kind

func (*GetByteCodesPacket) Kind() byte

func (*GetByteCodesPacket) Name

func (*GetByteCodesPacket) Name() string

type GetStorageRangesPacket

type GetStorageRangesPacket struct {
	ID       uint64        // Request ID to match up responses with
	Root     common.Hash   // Root hash of the account trie to serve
	Accounts []common.Hash // Account hashes of the storage tries to serve
	Origin   []byte        // Hash of the first storage slot to retrieve (large contract mode)
	Limit    []byte        // Hash of the last storage slot to retrieve (large contract mode)
	Bytes    uint64        // Soft limit at which to stop returning data
}

GetStorageRangesPacket represents an storage slot query.

func (*GetStorageRangesPacket) Kind

func (*GetStorageRangesPacket) Kind() byte

func (*GetStorageRangesPacket) Name

type GetTrieNodesPacket

type GetTrieNodesPacket struct {
	ID    uint64            // Request ID to match up responses with
	Root  common.Hash       // Root hash of the account trie to serve
	Paths []TrieNodePathSet // Trie node hashes to retrieve the nodes for
	Bytes uint64            // Soft limit at which to stop returning data
}

GetTrieNodesPacket represents a state trie node query.

func (*GetTrieNodesPacket) Kind

func (*GetTrieNodesPacket) Kind() byte

func (*GetTrieNodesPacket) Name

func (*GetTrieNodesPacket) Name() string

type Handler

type Handler func(peer *Peer) error

Handler is a callback to invoke from an outside runner after the boilerplate exchanges have passed.

type NodeInfo

type NodeInfo struct{}

NodeInfo represents a short summary of the `snap` sub-protocol metadata known about the host peer.

type Packet

type Packet interface {
	Name() string // Name returns a string corresponding to the message type.
	Kind() byte   // Kind returns the message type.
}

Packet represents a p2p message in the `snap` protocol.

type Peer

type Peer struct {
	*p2p.Peer // The embedded P2P package peer
	// contains filtered or unexported fields
}

Peer is a collection of relevant information we have about a `snap` peer.

func (*Peer) ID

func (p *Peer) ID() string

ID retrieves the peer's unique identifier.

func (*Peer) Log

func (p *Peer) Log() log.Logger

Log overrides the P2P logget with the higher level one containing only the id.

func (*Peer) RequestAccountRange

func (p *Peer) RequestAccountRange(id uint64, root common.Hash, origin, limit common.Hash, bytes uint64) error

RequestAccountRange fetches a batch of accounts rooted in a specific account trie, starting with the origin.

func (*Peer) RequestByteCodes

func (p *Peer) RequestByteCodes(id uint64, hashes []common.Hash, bytes uint64) error

RequestByteCodes fetches a batch of bytecodes by hash.

func (*Peer) RequestStorageRanges

func (p *Peer) RequestStorageRanges(id uint64, root common.Hash, accounts []common.Hash, origin, limit []byte, bytes uint64) error

RequestStorageRange fetches a batch of storage slots belonging to one or more accounts. If slots from only one accout is requested, an origin marker may also be used to retrieve from there.

func (*Peer) RequestTrieNodes

func (p *Peer) RequestTrieNodes(id uint64, root common.Hash, paths []TrieNodePathSet, bytes uint64) error

RequestTrieNodes fetches a batch of account or storage trie nodes rooted in a specificstate trie.

func (*Peer) Version

func (p *Peer) Version() uint

Version retrieves the peer's negoatiated `snap` protocol version.

type StorageData

type StorageData struct {
	Hash common.Hash // Hash of the storage slot
	Body []byte      // Data content of the slot
}

StorageData represents a single storage slot in a query response.

type StorageRangesPacket

type StorageRangesPacket struct {
	ID    uint64           // ID of the request this is a response for
	Slots [][]*StorageData // Lists of consecutive storage slots for the requested accounts
	Proof [][]byte         // Merkle proofs for the *last* slot range, if it's incomplete
}

StorageRangesPacket represents a storage slot query response.

func (*StorageRangesPacket) Kind

func (*StorageRangesPacket) Kind() byte

func (*StorageRangesPacket) Name

func (*StorageRangesPacket) Name() string

func (*StorageRangesPacket) Unpack

func (p *StorageRangesPacket) Unpack() ([][]common.Hash, [][][]byte)

Unpack retrieves the storage slots from the range packet and returns them in a split flat format that's more consistent with the internal data structures.

type SyncPeer

type SyncPeer interface {
	// ID retrieves the peer's unique identifier.
	ID() string

	// RequestAccountRange fetches a batch of accounts rooted in a specific account
	// trie, starting with the origin.
	RequestAccountRange(id uint64, root, origin, limit common.Hash, bytes uint64) error

	// RequestStorageRange fetches a batch of storage slots belonging to one or
	// more accounts. If slots from only one accout is requested, an origin marker
	// may also be used to retrieve from there.
	RequestStorageRanges(id uint64, root common.Hash, accounts []common.Hash, origin, limit []byte, bytes uint64) error

	// RequestByteCodes fetches a batch of bytecodes by hash.
	RequestByteCodes(id uint64, hashes []common.Hash, bytes uint64) error

	// RequestTrieNodes fetches a batch of account or storage trie nodes rooted in
	// a specificstate trie.
	RequestTrieNodes(id uint64, root common.Hash, paths []TrieNodePathSet, bytes uint64) error

	// Log retrieves the peer's own contextual logger.
	Log() log.Logger
}

SyncPeer abstracts out the methods required for a peer to be synced against with the goal of allowing the construction of mock peers without the full blown networking.

type Syncer

type Syncer struct {
	// contains filtered or unexported fields
}

Syncer is an Ethereum account and storage trie syncer based on snapshots and the snap protocol. It's purpose is to download all the accounts and storage slots from remote peers and reassemble chunks of the state trie, on top of which a state sync can be run to fix any gaps / overlaps.

Every network request has a variety of failure events:

  • The peer disconnects after task assignment, failing to send the request
  • The peer disconnects after sending the request, before delivering on it
  • The peer remains connected, but does not deliver a response in time
  • The peer delivers a stale response after a previous timeout
  • The peer delivers a refusal to serve the requested state

func NewSyncer

func NewSyncer(db ethdb.KeyValueStore) *Syncer

NewSyncer creates a new snapshot syncer to download the Ethereum state over the snap protocol.

func (*Syncer) OnAccounts

func (s *Syncer) OnAccounts(peer SyncPeer, id uint64, hashes []common.Hash, accounts [][]byte, proof [][]byte) error

OnAccounts is a callback method to invoke when a range of accounts are received from a remote peer.

func (*Syncer) OnByteCodes

func (s *Syncer) OnByteCodes(peer SyncPeer, id uint64, bytecodes [][]byte) error

OnByteCodes is a callback method to invoke when a batch of contract bytes codes are received from a remote peer.

func (*Syncer) OnStorage

func (s *Syncer) OnStorage(peer SyncPeer, id uint64, hashes [][]common.Hash, slots [][][]byte, proof [][]byte) error

OnStorage is a callback method to invoke when ranges of storage slots are received from a remote peer.

func (*Syncer) OnTrieNodes

func (s *Syncer) OnTrieNodes(peer SyncPeer, id uint64, trienodes [][]byte) error

OnTrieNodes is a callback method to invoke when a batch of trie nodes are received from a remote peer.

func (*Syncer) Register

func (s *Syncer) Register(peer SyncPeer) error

Register injects a new data source into the syncer's peerset.

func (*Syncer) Sync

func (s *Syncer) Sync(root common.Hash, cancel chan struct{}) error

Sync starts (or resumes a previous) sync cycle to iterate over an state trie with the given root and reconstruct the nodes based on the snapshot leaves. Previously downloaded segments will not be redownloaded of fixed, rather any errors will be healed after the leaves are fully accumulated.

func (*Syncer) Unregister

func (s *Syncer) Unregister(id string) error

Unregister injects a new data source into the syncer's peerset.

type TrieNodePathSet

type TrieNodePathSet [][]byte

TrieNodePathSet is a list of trie node paths to retrieve. A naive way to represent trie nodes would be a simple list of `account || storage` path segments concatenated, but that would be very wasteful on the network.

Instead, this array special cases the first element as the path in the account trie and the remaining elements as paths in the storage trie. To address an account node, the slice should have a length of 1 consisting of only the account path. There's no need to be able to address both an account node and a storage node in the same request as it cannot happen that a slot is accessed before the account path is fully expanded.

type TrieNodesPacket

type TrieNodesPacket struct {
	ID    uint64   // ID of the request this is a response for
	Nodes [][]byte // Requested state trie nodes
}

TrieNodesPacket represents a state trie node query response.

func (*TrieNodesPacket) Kind

func (*TrieNodesPacket) Kind() byte

func (*TrieNodesPacket) Name

func (*TrieNodesPacket) Name() string

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