spvwallet

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 Go to latest Published: Jul 15, 2016 License: MIT Imports: 32 Imported by: 0

README

spvwallet

Lightweight p2p SPV wallet in Go. It connects directly to the bitcoin p2p network to fetch headers, merkle blocks, and transactions. It mostly utilizes utilities from btcd and is partially based on https://github.com/LightningNetwork/lnd/tree/master/uspv.

Interfaces

These are the used interfaces:

Database

A sqlite implementation is included for testing but you should probably implement your own custom solution. Note there is no encryption in the example db.

  • Keys

The wallet manages an hd keychain (m/0'/change/index/) and stores they keys in this database. Used keys are marked in the db and a lookahead window is maintained to ensure all transactions can be recovered when restoring from seed.

  • Utxos

Stores all the utxos. The goal of bitcoin is to get lots of utxos, earning a high score.

  • Stxos

For record keeping. Stores what used to be utxos, but are no longer "u"txos, and are spent outpoints. It references the spending txid.

  • Txns

This bucket stores full serialized transactions which are refenced in the Stxos bucket. These can be used to re-play transactions in the case of re-orgs.

  • State

This has describes some miscellaneous global state variables of the database, such as what height it has synchronized up to.

Header file (currently headers.bin)

This is currently a bolt db which stores the chain of headers as well as orphans. A separate bucks tracks the tip of the chain. Cumulative work is calculated for each header and enables us to smoothly handle reorgs.

Synchronization overview

At startup addresses are gathered from the DNS seeds and it will maintain one or more connections (determined by the MAX_PEERS constant). It first asks for headers, providing the last known header, then loops through asking for headers until it receives an empty header message, which signals that headers are fully synchronized.

After header synchronization is complete, it requests merkle blocks starting at the last db height recorded in state. If the height is zero it requests from the last checkpoiint. Bloom filters are generated for the addresses and utxos known to the wallet. If too many false positives are received, a new filter is generated and sent. Once the merkle blocks have been received up to the header height, the wallet is considered synchronized and it will listen for new inv messages from the remote node.

TODO

  • Evict confirmed transactions from the db when a reorg is triggered.
  • Cache peer addresses and request more using getaddr. Only use the DNS seeds if we absolutely need to.
  • General refactoring, comments, and clean up.
  • Unit tests.

Documentation

Index

Constants

View Source 
const (
	MAX_HEADERS                = 2000
	MAINNET_CHECKPOINT_HEIGHT  = 407232
	TESTNET3_CHECKPOINT_HEIGHT = 895104
)
View Source 
const (
	EXTERNAL = 0
	INTERNAL = 1
)
View Source 
const (
	CONNECTING = 0
	CONNECTED  = 1
	DEAD       = 2
)
View Source 
const (
	PRIOIRTY = 0
	NORMAL   = 1
	ECONOMIC = 2
)
View Source 
const (
	SYNCING = 0
	WAITING = 1
	REORG   = 2
)
View Source 
const LOOKAHEADWINDOW = 100
View Source 
const MAX_PEERS = 10
View Source 
const (
	VERSION = 70012
)
View Source 
const WALLET_VERSION = "0.1.0"

Variables

View Source 
var (
	BKTHeaders  = []byte("Headers")
	BKTChainTip = []byte("ChainTip")
	KEYChainTip = []byte("ChainTip")
)
View Source 
var MainnetCheckpoint wire.BlockHeader
View Source 
var Testnet3Checkpoint wire.BlockHeader

Functions

func CheckDoubleSpends 

func CheckDoubleSpends(
	argTx *wire.MsgTx, txs []*wire.MsgTx) ([]*wire.ShaHash, error)

GetDoubleSpends takes a transaction and compares it with all transactions in the db. It returns a slice of all txids in the db which are double spent by the received tx.

func MakeMerkleParent 

func MakeMerkleParent(left *wire.ShaHash, right *wire.ShaHash) *wire.ShaHash

func NewCoin 

func NewCoin(txid []byte, index uint32, value btc.Amount, numConfs int64, scriptPubKey []byte) coinset.Coin

func OutPointsEqual 

func OutPointsEqual(a, b wire.OutPoint) bool

need this because before I was comparing pointers maybe? so they were the same outpoint but stored in 2 places so false negative?

Types

type Blockchain 

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

func NewBlockchain 

func NewBlockchain(filePath string, params *chaincfg.Params) *Blockchain

func (*Blockchain) CheckHeader 

func (b *Blockchain) CheckHeader(header wire.BlockHeader, prevHeader StoredHeader) (bool, uint32)

func (*Blockchain) CommitHeader 

func (b *Blockchain) CommitHeader(header wire.BlockHeader) (bool, error)

func (*Blockchain) GetBlockLocatorHashes 

func (b *Blockchain) GetBlockLocatorHashes() []*wire.ShaHash

func (*Blockchain) GetEpoch 

func (b *Blockchain) GetEpoch() (*wire.BlockHeader, error)

func (*Blockchain) GetNPrevBlockHashes 

func (b *Blockchain) GetNPrevBlockHashes(n int) []*wire.ShaHash

type ChainState 

type ChainState int

type Coin 

type Coin struct {
	TxHash       *wire.ShaHash
	TxIndex      uint32
	TxValue      btc.Amount
	TxNumConfs   int64
	ScriptPubKey []byte
}

func (*Coin) Hash 

func (c *Coin) Hash() *wire.ShaHash

func (*Coin) Index 

func (c *Coin) Index() uint32

func (*Coin) NumConfs 

func (c *Coin) NumConfs() int64

func (*Coin) PkScript 

func (c *Coin) PkScript() []byte

func (*Coin) Value 

func (c *Coin) Value() btc.Amount

func (*Coin) ValueAge 

func (c *Coin) ValueAge() int64

type ConnectionState 

type ConnectionState int

type Datastore 

type Datastore interface {
	Utxos() Utxos
	Stxos() Stxos
	Txns() Txns
	Keys() Keys
	State() State
}

type FeeLevel 

type FeeLevel int

type HashAndHeight 

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

HashAndHeight is needed instead of just height in case a fullnode responds abnormally (?) by sending out of order merkleblocks. we cache a merkleroot:height pair in the queue so we don't have to look them up from the disk. Also used when inv messages indicate blocks so we can add the header and parse the txs in one request instead of requesting headers first.

func NewRootAndHeight 

func NewRootAndHeight(b wire.ShaHash, h int32) (hah HashAndHeight)

NewRootAndHeight saves like 2 lines.

type HeaderDB 

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

func NewHeaderDB 

func NewHeaderDB(filePath string) *HeaderDB

func (*HeaderDB) GetBestHeader 

func (h *HeaderDB) GetBestHeader() (sh StoredHeader, err error)

func (*HeaderDB) GetPreviousHeader 

func (h *HeaderDB) GetPreviousHeader(header wire.BlockHeader) (sh StoredHeader, err error)

func (*HeaderDB) Height 

func (h *HeaderDB) Height() (uint32, error)

func (*HeaderDB) Print 

func (h *HeaderDB) Print()

func (*HeaderDB) Prune 

func (h *HeaderDB) Prune() error

func (*HeaderDB) Put 

func (h *HeaderDB) Put(sh StoredHeader, newBestHeader bool) error

type Headers 

type Headers interface {
	// Put a block header to the database
	// Total work and height are required to be calculated prior to insertion
	// If this is the new best header, the chain tip should also be updated
	Put(header StoredHeader, newBestHeader bool) error

	// Delete all headers after the MAX_HEADERS most recent
	Prune() error

	// Returns all information about the previous header
	GetPreviousHeader(header wire.BlockHeader) (StoredHeader, error)

	// Retreive the best header from the database
	GetBestHeader() (StoredHeader, error)

	// Get the height of chain
	Height() (uint32, error)

	// Print all headers
	Print()
}

type KeyPath 

type KeyPath struct {
	Purpose KeyPurpose
	Index   int
}

type KeyPurpose 

type KeyPurpose int

type Keys 

type Keys interface {
	// Put a bip32 key to the database
	Put(scriptPubKey []byte, keyPath KeyPath) error

	// Mark the script as used
	MarkKeyAsUsed(scriptPubKey []byte) error

	// Fetch the last index for the given key purpose
	// The bool should state whether the key has been used or not
	GetLastKeyIndex(purpose KeyPurpose) (int, bool, error)

	// Returns the first unused path for the given purpose
	GetPathForScript(scriptPubKey []byte) (KeyPath, error)

	// Get the first unused index for the given purpose
	GetUnused(purpose KeyPurpose) (int, error)

	// Fetch all key paths
	GetAll() ([]KeyPath, error)

	// Get the number of unused keys following the last used key
	// for each key purpose.
	GetLookaheadWindows() map[KeyPurpose]int
}

Keys provides a database interface for the wallet to save key material, track used keys, and manage the look ahead window.

type Peer 

type Peer struct {
	WBytes uint64 // total bytes written
	RBytes uint64 // total bytes read

	TS *TxStore // transaction store to write to

	// known good txids and their heights
	OKTxids map[wire.ShaHash]int32
	OKMutex sync.Mutex
	// contains filtered or unexported fields
}

func NewPeer 

func NewPeer(remoteNode string, blockchain *Blockchain, inTs *TxStore, params *chaincfg.Params, userAgent string, diconnectChan chan string, downloadPeer bool) (*Peer, error)

OpenPV starts a

func (*Peer) AskForBlocks 

func (p *Peer) AskForBlocks() error

AskForMerkBlocks requests blocks from current to last right now this asks for 1 block per getData message. Maybe it's faster to ask for many in a each message?

func (*Peer) AskForHeaders 

func (p *Peer) AskForHeaders() error

func (*Peer) AskForMerkleBlock 

func (p *Peer) AskForMerkleBlock(hash wire.ShaHash)

func (*Peer) AskForTx 

func (p *Peer) AskForTx(txid wire.ShaHash)

AskForTx requests a tx we heard about from an inv message. It's one at a time but should be fast enough. I don't like this function because SPV shouldn't even ask...

func (*Peer) GetDataHandler 

func (p *Peer) GetDataHandler(m *wire.MsgGetData)

GetDataHandler responds to requests for tx data, which happen after advertising our txs via an inv message

func (*Peer) HeaderHandler 

func (p *Peer) HeaderHandler(m *wire.MsgHeaders)

func (*Peer) IngestBlockAndHeader 

func (p *Peer) IngestBlockAndHeader(m *wire.MsgMerkleBlock)

func (*Peer) IngestHeaders 

func (p *Peer) IngestHeaders(m *wire.MsgHeaders) (bool, error)

IngestHeaders takes in a bunch of headers and appends them to the local header file, checking that they fit. If there's no headers, it assumes we're done and returns false. If it worked it assumes there's more to request and returns true.

func (*Peer) IngestMerkleBlock 

func (p *Peer) IngestMerkleBlock(m *wire.MsgMerkleBlock)

func (*Peer) InvHandler 

func (p *Peer) InvHandler(m *wire.MsgInv)

func (*Peer) NewOutgoingTx 

func (p *Peer) NewOutgoingTx(tx *wire.MsgTx) error

func (*Peer) PongBack 

func (p *Peer) PongBack(nonce uint64)

func (*Peer) Rebroadcast 

func (p *Peer) Rebroadcast()

Rebroadcast sends an inv message of all the unconfirmed txs the db is aware of. This is called after every sync. Only txids so hopefully not too annoying for nodes.

func (*Peer) SendFilter 

func (p *Peer) SendFilter(f *bloom.Filter)

func (*Peer) TxHandler 

func (p *Peer) TxHandler(m *wire.MsgTx)

TxHandler takes in transaction messages that come in from either a request after an inv message or after a merkle block message.

func (*Peer) UpdateFilterAndSend 

func (p *Peer) UpdateFilterAndSend()

type SPVWallet 

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

func NewSPVWallet 

func NewSPVWallet(mnemonic string, params *chaincfg.Params, maxFee uint64, lowFee uint64, mediumFee uint64, highFee uint64, feeApi,
	repoPath string, db Datastore, userAgent string, logger logging.LeveledBackend) *SPVWallet

func (*SPVWallet) Balance 

func (w *SPVWallet) Balance() (confirmed, unconfirmed int64)

func (*SPVWallet) CurrencyCode 

func (w *SPVWallet) CurrencyCode() string

func (*SPVWallet) CurrentAddress 

func (w *SPVWallet) CurrentAddress(purpose KeyPurpose) *btc.AddressPubKeyHash

func (*SPVWallet) MasterPrivateKey 

func (w *SPVWallet) MasterPrivateKey() *hd.ExtendedKey

func (*SPVWallet) MasterPublicKey 

func (w *SPVWallet) MasterPublicKey() *hd.ExtendedKey

func (*SPVWallet) Params 

func (w *SPVWallet) Params() *chaincfg.Params

func (*SPVWallet) Spend 

func (w *SPVWallet) Spend(amount int64, addr btc.Address, feeLevel FeeLevel) error

func (*SPVWallet) Start 

func (w *SPVWallet) Start()

type State 

type State interface {
	// Put a key/value pair to the database
	Put(key, value string) error

	// Get a value given the key
	Get(key string) (string, error)
}

type StoredHeader 

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

type Stxo 

type Stxo struct {
	Utxo        Utxo         // when it used to be a utxo
	SpendHeight int32        // height at which it met its demise
	SpendTxid   wire.ShaHash // the tx that consumed it
}

Stxo is a utxo that has moved on.

type Stxos 

type Stxos interface {
	// Put a stxo to the database
	Put(stxo Stxo) error

	// Fetch all stxos from the db
	GetAll() ([]Stxo, error)

	// Delete a stxo from the db
	Delete(stxo Stxo) error
}

type TxStore 

type TxStore struct {
	Adrs []btcutil.Address

	Param *chaincfg.Params
	// contains filtered or unexported fields
}

func NewTxStore 

func NewTxStore(p *chaincfg.Params, db Datastore, masterPrivKey *hd.ExtendedKey) *TxStore

func (*TxStore) GetCurrentKey 

func (t *TxStore) GetCurrentKey(purpose KeyPurpose) *hd.ExtendedKey

func (*TxStore) GetDBSyncHeight 

func (ts *TxStore) GetDBSyncHeight() (int32, error)

SyncHeight returns the chain height to which the db has synced

func (*TxStore) GetFreshKey 

func (t *TxStore) GetFreshKey(purpose KeyPurpose) *hd.ExtendedKey

func (*TxStore) GetKeyForScript 

func (t *TxStore) GetKeyForScript(scriptPubKey []byte) (*hd.ExtendedKey, error)

func (*TxStore) GetKeys 

func (t *TxStore) GetKeys() []*hd.ExtendedKey

func (*TxStore) GetPendingInv 

func (ts *TxStore) GetPendingInv() (*wire.MsgInv, error)

GetPendingInv returns an inv message containing all txs known to the db which are at height 0 (not known to be confirmed). This can be useful on startup or to rebroadcast unconfirmed txs.

func (*TxStore) GimmeFilter 

func (t *TxStore) GimmeFilter() (*bloom.Filter, error)

... or I'm gonna fade away

func (*TxStore) Ingest 

func (ts *TxStore) Ingest(tx *wire.MsgTx, height int32) (uint32, error)

Ingest puts a tx into the DB atomically. This can result in a gain, a loss, or no result. Gain or loss in satoshis is returned.

func (*TxStore) PopulateAdrs 

func (ts *TxStore) PopulateAdrs() error

PopulateAdrs just puts a bunch of adrs in ram; it doesn't touch the DB

func (*TxStore) SetDBSyncHeight 

func (ts *TxStore) SetDBSyncHeight(n int32) error

SetDBSyncHeight sets sync height of the db, indicated the latest block of which it has ingested all the transactions.

type Txns 

type Txns interface {

	// Put a new transaction to the database
	Put(txn *wire.MsgTx) error

	// Fetch a tx given it's hash
	Get(txid wire.ShaHash) (*wire.MsgTx, error)

	// Fetch all transactions from the db
	GetAll() ([]*wire.MsgTx, error)

	// Delete a transactions from the db
	Delete(txid *wire.ShaHash) error
}

type Utxo 

type Utxo struct {
	Op wire.OutPoint // where

	// all the info needed to spend
	AtHeight int32 // block height where this tx was confirmed, 0 for unconf
	Value    int64 // higher is better

	ScriptPubkey []byte
}

type Utxos 

type Utxos interface {
	// Put a utxo to the database
	Put(utxo Utxo) error

	// Fetch all utxos from the db
	GetAll() ([]Utxo, error)

	// Delete a utxo from the db
	Delete(utxo Utxo) error
}

Source Files

View all Source files

Directories

Path Synopsis
db

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