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Merge btcchain repo into blockchain directory.

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blockchain
==========
[![Build Status](http://img.shields.io/travis/btcsuite/btcd.svg)]
(https://travis-ci.org/btcsuite/btcd) [![ISC License]
(http://img.shields.io/badge/license-ISC-blue.svg)](http://copyfree.org)
Package blockchain implements bitcoin block handling and chain selection rules.
The test coverage is currently only around 60%, but will be increasing over
time. See `test_coverage.txt` for the gocov coverage report. Alternatively, if
you are running a POSIX OS, you can run the `cov_report.sh` script for a
real-time report. Package blockchain is licensed under the liberal ISC license.
There is an associated blog post about the release of this package
[here](https://blog.conformal.com/btcchain-the-bitcoin-chain-package-from-bctd/).
This package has intentionally been designed so it can be used as a standalone
package for any projects needing to handle processing of blocks into the bitcoin
block chain.
## Documentation
[![GoDoc](https://img.shields.io/badge/godoc-reference-blue.svg)]
(http://godoc.org/github.com/btcsuite/btcd/blockchain)
Full `go doc` style documentation for the project can be viewed online without
installing this package by using the GoDoc site here:
http://godoc.org/github.com/btcsuite/btcd/blockchain
You can also view the documentation locally once the package is installed with
the `godoc` tool by running `godoc -http=":6060"` and pointing your browser to
http://localhost:6060/pkg/github.com/btcsuite/btcd/blockchain
## Installation
```bash
$ go get github.com/btcsuite/btcd/blockchain
```
## Bitcoin Chain Processing Overview
Before a block is allowed into the block chain, it must go through an intensive
series of validation rules. The following list serves as a general outline of
those rules to provide some intuition into what is going on under the hood, but
is by no means exhaustive:
- Reject duplicate blocks
- Perform a series of sanity checks on the block and its transactions such as
verifying proof of work, timestamps, number and character of transactions,
transaction amounts, script complexity, and merkle root calculations
- Compare the block against predetermined checkpoints for expected timestamps
and difficulty based on elapsed time since the checkpoint
- Save the most recent orphan blocks for a limited time in case their parent
blocks become available
- Stop processing if the block is an orphan as the rest of the processing
depends on the block's position within the block chain
- Perform a series of more thorough checks that depend on the block's position
within the block chain such as verifying block difficulties adhere to
difficulty retarget rules, timestamps are after the median of the last
several blocks, all transactions are finalized, checkpoint blocks match, and
block versions are in line with the previous blocks
- Determine how the block fits into the chain and perform different actions
accordingly in order to ensure any side chains which have higher difficulty
than the main chain become the new main chain
- When a block is being connected to the main chain (either through
reorganization of a side chain to the main chain or just extending the
main chain), perform further checks on the block's transactions such as
verifying transaction duplicates, script complexity for the combination of
connected scripts, coinbase maturity, double spends, and connected
transaction values
- Run the transaction scripts to verify the spender is allowed to spend the
coins
- Insert the block into the block database
## Examples
* [ProcessBlock Example]
(http://godoc.org/github.com/btcsuite/btcd/blockchain#example-BlockChain-ProcessBlock)
Demonstrates how to create a new chain instance and use ProcessBlock to
attempt to attempt add a block to the chain. This example intentionally
attempts to insert a duplicate genesis block to illustrate how an invalid
block is handled.
* [CompactToBig Example]
(http://godoc.org/github.com/btcsuite/btcd/blockchain#example-CompactToBig)
Demonstrates how to convert the compact "bits" in a block header which
represent the target difficulty to a big integer and display it using the
typical hex notation.
* [BigToCompact Example]
(http://godoc.org/github.com/btcsuite/btcd/blockchain#example-BigToCompact)
Demonstrates how to convert how to convert a target difficulty into the
compact "bits" in a block header which represent that target difficulty.
## GPG Verification Key
All official release tags are signed by Conformal so users can ensure the code
has not been tampered with and is coming from Conformal. To verify the
signature perform the following:
- Download the public key from the Conformal website at
https://opensource.conformal.com/GIT-GPG-KEY-conformal.txt
- Import the public key into your GPG keyring:
```bash
gpg --import GIT-GPG-KEY-conformal.txt
```
- Verify the release tag with the following command where `TAG_NAME` is a
placeholder for the specific tag:
```bash
git tag -v TAG_NAME
```
## License
Package blockchain is licensed under the [copyfree](http://copyfree.org) ISC
License.

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"fmt"
"github.com/btcsuite/btcutil"
)
// maybeAcceptBlock potentially accepts a block into the memory block chain.
// It performs several validation checks which depend on its position within
// the block chain before adding it. The block is expected to have already gone
// through ProcessBlock before calling this function with it.
//
// The flags modify the behavior of this function as follows:
// - BFFastAdd: The somewhat expensive BIP0034 validation is not performed.
// - BFDryRun: The memory chain index will not be pruned and no accept
// notification will be sent since the block is not being accepted.
func (b *BlockChain) maybeAcceptBlock(block *btcutil.Block, flags BehaviorFlags) error {
fastAdd := flags&BFFastAdd == BFFastAdd
dryRun := flags&BFDryRun == BFDryRun
// Get a block node for the block previous to this one. Will be nil
// if this is the genesis block.
prevNode, err := b.getPrevNodeFromBlock(block)
if err != nil {
log.Errorf("getPrevNodeFromBlock: %v", err)
return err
}
// The height of this block is one more than the referenced previous
// block.
blockHeight := int64(0)
if prevNode != nil {
blockHeight = prevNode.height + 1
}
block.SetHeight(blockHeight)
blockHeader := &block.MsgBlock().Header
if !fastAdd {
// Ensure the difficulty specified in the block header matches
// the calculated difficulty based on the previous block and
// difficulty retarget rules.
expectedDifficulty, err := b.calcNextRequiredDifficulty(prevNode,
block.MsgBlock().Header.Timestamp)
if err != nil {
return err
}
blockDifficulty := blockHeader.Bits
if blockDifficulty != expectedDifficulty {
str := "block difficulty of %d is not the expected value of %d"
str = fmt.Sprintf(str, blockDifficulty, expectedDifficulty)
return ruleError(ErrUnexpectedDifficulty, str)
}
// Ensure the timestamp for the block header is after the
// median time of the last several blocks (medianTimeBlocks).
medianTime, err := b.calcPastMedianTime(prevNode)
if err != nil {
log.Errorf("calcPastMedianTime: %v", err)
return err
}
if !blockHeader.Timestamp.After(medianTime) {
str := "block timestamp of %v is not after expected %v"
str = fmt.Sprintf(str, blockHeader.Timestamp,
medianTime)
return ruleError(ErrTimeTooOld, str)
}
// Ensure all transactions in the block are finalized.
for _, tx := range block.Transactions() {
if !IsFinalizedTransaction(tx, blockHeight,
blockHeader.Timestamp) {
str := fmt.Sprintf("block contains "+
"unfinalized transaction %v", tx.Sha())
return ruleError(ErrUnfinalizedTx, str)
}
}
}
// Ensure chain matches up to predetermined checkpoints.
// It's safe to ignore the error on Sha since it's already cached.
blockHash, _ := block.Sha()
if !b.verifyCheckpoint(blockHeight, blockHash) {
str := fmt.Sprintf("block at height %d does not match "+
"checkpoint hash", blockHeight)
return ruleError(ErrBadCheckpoint, str)
}
// Find the previous checkpoint and prevent blocks which fork the main
// chain before it. This prevents storage of new, otherwise valid,
// blocks which build off of old blocks that are likely at a much easier
// difficulty and therefore could be used to waste cache and disk space.
checkpointBlock, err := b.findPreviousCheckpoint()
if err != nil {
return err
}
if checkpointBlock != nil && blockHeight < checkpointBlock.Height() {
str := fmt.Sprintf("block at height %d forks the main chain "+
"before the previous checkpoint at height %d",
blockHeight, checkpointBlock.Height())
return ruleError(ErrForkTooOld, str)
}
if !fastAdd {
// Reject version 1 blocks once a majority of the network has
// upgraded. This is part of BIP0034.
if blockHeader.Version < 2 {
if b.isMajorityVersion(2, prevNode,
b.netParams.BlockV1RejectNumRequired,
b.netParams.BlockV1RejectNumToCheck) {
str := "new blocks with version %d are no " +
"longer valid"
str = fmt.Sprintf(str, blockHeader.Version)
return ruleError(ErrBlockVersionTooOld, str)
}
}
// Ensure coinbase starts with serialized block heights for
// blocks whose version is the serializedHeightVersion or
// newer once a majority of the network has upgraded. This is
// part of BIP0034.
if blockHeader.Version >= serializedHeightVersion {
if b.isMajorityVersion(serializedHeightVersion,
prevNode,
b.netParams.CoinbaseBlockHeightNumRequired,
b.netParams.CoinbaseBlockHeightNumToCheck) {
expectedHeight := int64(0)
if prevNode != nil {
expectedHeight = prevNode.height + 1
}
coinbaseTx := block.Transactions()[0]
err := checkSerializedHeight(coinbaseTx,
expectedHeight)
if err != nil {
return err
}
}
}
}
// Prune block nodes which are no longer needed before creating
// a new node.
if !dryRun {
err = b.pruneBlockNodes()
if err != nil {
return err
}
}
// Create a new block node for the block and add it to the in-memory
// block chain (could be either a side chain or the main chain).
newNode := newBlockNode(blockHeader, blockHash, blockHeight)
if prevNode != nil {
newNode.parent = prevNode
newNode.height = blockHeight
newNode.workSum.Add(prevNode.workSum, newNode.workSum)
}
// Connect the passed block to the chain while respecting proper chain
// selection according to the chain with the most proof of work. This
// also handles validation of the transaction scripts.
err = b.connectBestChain(newNode, block, flags)
if err != nil {
return err
}
// Notify the caller that the new block was accepted into the block
// chain. The caller would typically want to react by relaying the
// inventory to other peers.
if !dryRun {
b.sendNotification(NTBlockAccepted, block)
}
return nil
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"github.com/btcsuite/btcwire"
)
// BlockLocator is used to help locate a specific block. The algorithm for
// building the block locator is to add the hashes in reverse order until
// the genesis block is reached. In order to keep the list of locator hashes
// to a reasonable number of entries, first the most recent previous 10 block
// hashes are added, then the step is doubled each loop iteration to
// exponentially decrease the number of hashes as a function of the distance
// from the block being located.
//
// For example, assume you have a block chain with a side chain as depicted
// below:
// genesis -> 1 -> 2 -> ... -> 15 -> 16 -> 17 -> 18
// \-> 16a -> 17a
//
// The block locator for block 17a would be the hashes of blocks:
// [17a 16a 15 14 13 12 11 10 9 8 6 2 genesis]
type BlockLocator []*btcwire.ShaHash
// BlockLocatorFromHash returns a block locator for the passed block hash.
// See BlockLocator for details on the algotirhm used to create a block locator.
//
// In addition to the general algorithm referenced above, there are a couple of
// special cases which are handled:
//
// - If the genesis hash is passed, there are no previous hashes to add and
// therefore the block locator will only consist of the genesis hash
// - If the passed hash is not currently known, the block locator will only
// consist of the passed hash
func (b *BlockChain) BlockLocatorFromHash(hash *btcwire.ShaHash) BlockLocator {
// The locator contains the requested hash at the very least.
locator := make(BlockLocator, 0, btcwire.MaxBlockLocatorsPerMsg)
locator = append(locator, hash)
// Nothing more to do if a locator for the genesis hash was requested.
if hash.IsEqual(b.netParams.GenesisHash) {
return locator
}
// Attempt to find the height of the block that corresponds to the
// passed hash, and if it's on a side chain, also find the height at
// which it forks from the main chain.
blockHeight := int64(-1)
forkHeight := int64(-1)
node, exists := b.index[*hash]
if !exists {
// Try to look up the height for passed block hash. Assume an
// error means it doesn't exist and just return the locator for
// the block itself.
block, err := b.db.FetchBlockBySha(hash)
if err != nil {
return locator
}
blockHeight = block.Height()
} else {
blockHeight = node.height
// Find the height at which this node forks from the main chain
// if the node is on a side chain.
if !node.inMainChain {
for n := node; n.parent != nil; n = n.parent {
if n.inMainChain {
forkHeight = n.height
break
}
}
}
}
// Generate the block locators according to the algorithm described in
// in the BlockLocator comment and make sure to leave room for the
// final genesis hash.
iterNode := node
increment := int64(1)
for len(locator) < btcwire.MaxBlockLocatorsPerMsg-1 {
// Once there are 10 locators, exponentially increase the
// distance between each block locator.
if len(locator) > 10 {
increment *= 2
}
blockHeight -= increment
if blockHeight < 1 {
break
}
// As long as this is still on the side chain, walk backwards
// along the side chain nodes to each block height.
if forkHeight != -1 && blockHeight > forkHeight {
// Intentionally use parent field instead of the
// getPrevNodeFromNode function since we don't want to
// dynamically load nodes when building block locators.
// Side chain blocks should always be in memory already,
// and if they aren't for some reason it's ok to skip
// them.
for iterNode != nil && blockHeight > iterNode.height {
iterNode = iterNode.parent
}
if iterNode != nil && iterNode.height == blockHeight {
locator = append(locator, iterNode.hash)
}
continue
}
// The desired block height is in the main chain, so look it up
// from the main chain database.
h, err := b.db.FetchBlockShaByHeight(blockHeight)
if err != nil {
// This shouldn't happen and it's ok to ignore block
// locators, so just continue to the next one.
log.Warnf("Lookup of known valid height failed %v",
blockHeight)
continue
}
locator = append(locator, h)
}
// Append the appropriate genesis block.
locator = append(locator, b.netParams.GenesisHash)
return locator
}
// LatestBlockLocator returns a block locator for the latest known tip of the
// main (best) chain.
func (b *BlockChain) LatestBlockLocator() (BlockLocator, error) {
// Lookup the latest main chain hash if the best chain hasn't been set
// yet.
if b.bestChain == nil {
// Get the latest block hash for the main chain from the
// database.
hash, _, err := b.db.NewestSha()
if err != nil {
return nil, err
}
return b.BlockLocatorFromHash(hash), nil
}
// The best chain is set, so use its hash.
return b.BlockLocatorFromHash(b.bestChain.hash), nil
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"testing"
"github.com/btcsuite/btcd/blockchain"
"github.com/btcsuite/btcnet"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
// TestHaveBlock tests the HaveBlock API to ensure proper functionality.
func TestHaveBlock(t *testing.T) {
// Load up blocks such that there is a side chain.
// (genesis block) -> 1 -> 2 -> 3 -> 4
// \-> 3a
testFiles := []string{
"blk_0_to_4.dat.bz2",
"blk_3A.dat.bz2",
}
var blocks []*btcutil.Block
for _, file := range testFiles {
blockTmp, err := loadBlocks(file)
if err != nil {
t.Errorf("Error loading file: %v\n", err)
return
}
for _, block := range blockTmp {
blocks = append(blocks, block)
}
}
// Create a new database and chain instance to run tests against.
chain, teardownFunc, err := chainSetup("haveblock")
if err != nil {
t.Errorf("Failed to setup chain instance: %v", err)
return
}
defer teardownFunc()
// Since we're not dealing with the real block chain, disable
// checkpoints and set the coinbase maturity to 1.
chain.DisableCheckpoints(true)
blockchain.TstSetCoinbaseMaturity(1)
timeSource := blockchain.NewMedianTime()
for i := 1; i < len(blocks); i++ {
isOrphan, err := chain.ProcessBlock(blocks[i], timeSource,
blockchain.BFNone)
if err != nil {
t.Errorf("ProcessBlock fail on block %v: %v\n", i, err)
return
}
if isOrphan {
t.Errorf("ProcessBlock incorrectly returned block %v "+
"is an orphan\n", i)
return
}
}
// Insert an orphan block.
isOrphan, err := chain.ProcessBlock(btcutil.NewBlock(&Block100000),
timeSource, blockchain.BFNone)
if err != nil {
t.Errorf("Unable to process block: %v", err)
return
}
if !isOrphan {
t.Errorf("ProcessBlock indicated block is an not orphan when " +
"it should be\n")
return
}
tests := []struct {
hash string
want bool
}{
// Genesis block should be present (in the main chain).
{hash: btcnet.MainNetParams.GenesisHash.String(), want: true},
// Block 3a should be present (on a side chain).
{hash: "00000000474284d20067a4d33f6a02284e6ef70764a3a26d6a5b9df52ef663dd", want: true},
// Block 100000 should be present (as an orphan).
{hash: "000000000003ba27aa200b1cecaad478d2b00432346c3f1f3986da1afd33e506", want: true},
// Random hashes should not be availble.
{hash: "123", want: false},
}
for i, test := range tests {
hash, err := btcwire.NewShaHashFromStr(test.hash)
if err != nil {
t.Errorf("NewShaHashFromStr: %v", err)
continue
}
result, err := chain.HaveBlock(hash)
if err != nil {
t.Errorf("HaveBlock #%d unexpected error: %v", i, err)
return
}
if result != test.want {
t.Errorf("HaveBlock #%d got %v want %v", i, result,
test.want)
continue
}
}
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"fmt"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcnet"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
// CheckpointConfirmations is the number of blocks before the end of the current
// best block chain that a good checkpoint candidate must be.
const CheckpointConfirmations = 2016
// newShaHashFromStr converts the passed big-endian hex string into a
// btcwire.ShaHash. It only differs from the one available in btcwire in that
// it ignores the error since it will only (and must only) be called with
// hard-coded, and therefore known good, hashes.
func newShaHashFromStr(hexStr string) *btcwire.ShaHash {
sha, _ := btcwire.NewShaHashFromStr(hexStr)
return sha
}
// DisableCheckpoints provides a mechanism to disable validation against
// checkpoints which you DO NOT want to do in production. It is provided only
// for debug purposes.
func (b *BlockChain) DisableCheckpoints(disable bool) {
b.noCheckpoints = disable
}
// Checkpoints returns a slice of checkpoints (regardless of whether they are
// already known). When checkpoints are disabled or there are no checkpoints
// for the active network, it will return nil.
func (b *BlockChain) Checkpoints() []btcnet.Checkpoint {
if b.noCheckpoints || len(b.netParams.Checkpoints) == 0 {
return nil
}
return b.netParams.Checkpoints
}
// LatestCheckpoint returns the most recent checkpoint (regardless of whether it
// is already known). When checkpoints are disabled or there are no checkpoints
// for the active network, it will return nil.
func (b *BlockChain) LatestCheckpoint() *btcnet.Checkpoint {
if b.noCheckpoints || len(b.netParams.Checkpoints) == 0 {
return nil
}
checkpoints := b.netParams.Checkpoints
return &checkpoints[len(checkpoints)-1]
}
// verifyCheckpoint returns whether the passed block height and hash combination
// match the hard-coded checkpoint data. It also returns true if there is no
// checkpoint data for the passed block height.
func (b *BlockChain) verifyCheckpoint(height int64, hash *btcwire.ShaHash) bool {
if b.noCheckpoints || len(b.netParams.Checkpoints) == 0 {
return true
}
// Nothing to check if there is no checkpoint data for the block height.
checkpoint, exists := b.checkpointsByHeight[height]
if !exists {
return true
}
if !checkpoint.Hash.IsEqual(hash) {
return false
}
log.Infof("Verified checkpoint at height %d/block %s", checkpoint.Height,
checkpoint.Hash)
return true
}
// findPreviousCheckpoint finds the most recent checkpoint that is already
// available in the downloaded portion of the block chain and returns the
// associated block. It returns nil if a checkpoint can't be found (this should
// really only happen for blocks before the first checkpoint).
func (b *BlockChain) findPreviousCheckpoint() (*btcutil.Block, error) {
if b.noCheckpoints || len(b.netParams.Checkpoints) == 0 {
return nil, nil
}
// No checkpoints.
checkpoints := b.netParams.Checkpoints
numCheckpoints := len(checkpoints)
if numCheckpoints == 0 {
return nil, nil
}
// Perform the initial search to find and cache the latest known
// checkpoint if the best chain is not known yet or we haven't already
// previously searched.
if b.bestChain == nil || (b.checkpointBlock == nil && b.nextCheckpoint == nil) {
// Loop backwards through the available checkpoints to find one
// that we already have.
checkpointIndex := -1
for i := numCheckpoints - 1; i >= 0; i-- {
exists, err := b.db.ExistsSha(checkpoints[i].Hash)
if err != nil {
return nil, err
}
if exists {
checkpointIndex = i
break
}
}
// No known latest checkpoint. This will only happen on blocks
// before the first known checkpoint. So, set the next expected
// checkpoint to the first checkpoint and return the fact there
// is no latest known checkpoint block.
if checkpointIndex == -1 {
b.nextCheckpoint = &checkpoints[0]
return nil, nil
}
// Cache the latest known checkpoint block for future lookups.
checkpoint := checkpoints[checkpointIndex]
block, err := b.db.FetchBlockBySha(checkpoint.Hash)
if err != nil {
return nil, err
}
b.checkpointBlock = block
// Set the next expected checkpoint block accordingly.
b.nextCheckpoint = nil
if checkpointIndex < numCheckpoints-1 {
b.nextCheckpoint = &checkpoints[checkpointIndex+1]
}
return block, nil
}
// At this point we've already searched for the latest known checkpoint,
// so when there is no next checkpoint, the current checkpoint lockin
// will always be the latest known checkpoint.
if b.nextCheckpoint == nil {
return b.checkpointBlock, nil
}
// When there is a next checkpoint and the height of the current best
// chain does not exceed it, the current checkpoint lockin is still
// the latest known checkpoint.
if b.bestChain.height < b.nextCheckpoint.Height {
return b.checkpointBlock, nil
}
// We've reached or exceeded the next checkpoint height. Note that
// once a checkpoint lockin has been reached, forks are prevented from
// any blocks before the checkpoint, so we don't have to worry about the
// checkpoint going away out from under us due to a chain reorganize.
// Cache the latest known checkpoint block for future lookups. Note
// that if this lookup fails something is very wrong since the chain
// has already passed the checkpoint which was verified as accurate
// before inserting it.
block, err := b.db.FetchBlockBySha(b.nextCheckpoint.Hash)
if err != nil {
return nil, err
}
b.checkpointBlock = block
// Set the next expected checkpoint.
checkpointIndex := -1
for i := numCheckpoints - 1; i >= 0; i-- {
if checkpoints[i].Hash.IsEqual(b.nextCheckpoint.Hash) {
checkpointIndex = i
break
}
}
b.nextCheckpoint = nil
if checkpointIndex != -1 && checkpointIndex < numCheckpoints-1 {
b.nextCheckpoint = &checkpoints[checkpointIndex+1]
}
return b.checkpointBlock, nil
}
// isNonstandardTransaction determines whether a transaction contains any
// scripts which are not one of the standard types.
func isNonstandardTransaction(tx *btcutil.Tx) bool {
// TODO(davec): Should there be checks for the input signature scripts?
// Check all of the output public key scripts for non-standard scripts.
for _, txOut := range tx.MsgTx().TxOut {
scriptClass := txscript.GetScriptClass(txOut.PkScript)
if scriptClass == txscript.NonStandardTy {
return true
}
}
return false
}
// IsCheckpointCandidate returns whether or not the passed block is a good
// checkpoint candidate.
//
// The factors used to determine a good checkpoint are:
// - The block must be in the main chain
// - The block must be at least 'CheckpointConfirmations' blocks prior to the
// current end of the main chain
// - The timestamps for the blocks before and after the checkpoint must have
// timestamps which are also before and after the checkpoint, respectively
// (due to the median time allowance this is not always the case)
// - The block must not contain any strange transaction such as those with
// nonstandard scripts
//
// The intent is that candidates are reviewed by a developer to make the final
// decision and then manually added to the list of checkpoints for a network.
func (b *BlockChain) IsCheckpointCandidate(block *btcutil.Block) (bool, error) {
// Checkpoints must be enabled.
if b.noCheckpoints {
return false, fmt.Errorf("checkpoints are disabled")
}
blockHash, err := block.Sha()
if err != nil {
return false, err
}
// A checkpoint must be in the main chain.
exists, err := b.db.ExistsSha(blockHash)
if err != nil {
return false, err
}
if !exists {
return false, nil
}
// A checkpoint must be at least CheckpointConfirmations blocks before
// the end of the main chain.
blockHeight := block.Height()
_, mainChainHeight, err := b.db.NewestSha()
if err != nil {
return false, err
}
if blockHeight > (mainChainHeight - CheckpointConfirmations) {
return false, nil
}
// Get the previous block.
prevHash := &block.MsgBlock().Header.PrevBlock
prevBlock, err := b.db.FetchBlockBySha(prevHash)
if err != nil {
return false, err
}
// Get the next block.
nextHash, err := b.db.FetchBlockShaByHeight(blockHeight + 1)
if err != nil {
return false, err
}
nextBlock, err := b.db.FetchBlockBySha(nextHash)
if err != nil {
return false, err
}
// A checkpoint must have timestamps for the block and the blocks on
// either side of it in order (due to the median time allowance this is
// not always the case).
prevTime := prevBlock.MsgBlock().Header.Timestamp
curTime := block.MsgBlock().Header.Timestamp
nextTime := nextBlock.MsgBlock().Header.Timestamp
if prevTime.After(curTime) || nextTime.Before(curTime) {
return false, nil
}
// A checkpoint must have transactions that only contain standard
// scripts.
for _, tx := range block.Transactions() {
if isNonstandardTransaction(tx) {
return false, nil
}
}
return true, nil
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"compress/bzip2"
"encoding/binary"
"fmt"
"io"
"os"
"path/filepath"
"strings"
"github.com/btcsuite/btcd/blockchain"
"github.com/btcsuite/btcd/database"
_ "github.com/btcsuite/btcd/database/ldb"
_ "github.com/btcsuite/btcd/database/memdb"
"github.com/btcsuite/btcnet"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
// testDbType is the database backend type to use for the tests.
const testDbType = "memdb"
// testDbRoot is the root directory used to create all test databases.
const testDbRoot = "testdbs"
// filesExists returns whether or not the named file or directory exists.
func fileExists(name string) bool {
if _, err := os.Stat(name); err != nil {
if os.IsNotExist(err) {
return false
}
}
return true
}
// isSupportedDbType returns whether or not the passed database type is
// currently supported.
func isSupportedDbType(dbType string) bool {
supportedDBs := database.SupportedDBs()
for _, sDbType := range supportedDBs {
if dbType == sDbType {
return true
}
}
return false
}
// chainSetup is used to create a new db and chain instance with the genesis
// block already inserted. In addition to the new chain instnce, it returns
// a teardown function the caller should invoke when done testing to clean up.
func chainSetup(dbName string) (*blockchain.BlockChain, func(), error) {
if !isSupportedDbType(testDbType) {
return nil, nil, fmt.Errorf("unsupported db type %v", testDbType)
}
// Handle memory database specially since it doesn't need the disk
// specific handling.
var db database.Db
var teardown func()
if testDbType == "memdb" {
ndb, err := database.CreateDB(testDbType)
if err != nil {
return nil, nil, fmt.Errorf("error creating db: %v", err)
}
db = ndb
// Setup a teardown function for cleaning up. This function is
// returned to the caller to be invoked when it is done testing.
teardown = func() {
db.Close()
}
} else {
// Create the root directory for test databases.
if !fileExists(testDbRoot) {
if err := os.MkdirAll(testDbRoot, 0700); err != nil {
err := fmt.Errorf("unable to create test db "+
"root: %v", err)
return nil, nil, err
}
}
// Create a new database to store the accepted blocks into.
dbPath := filepath.Join(testDbRoot, dbName)
_ = os.RemoveAll(dbPath)
ndb, err := database.CreateDB(testDbType, dbPath)
if err != nil {
return nil, nil, fmt.Errorf("error creating db: %v", err)
}
db = ndb
// Setup a teardown function for cleaning up. This function is
// returned to the caller to be invoked when it is done testing.
teardown = func() {
dbVersionPath := filepath.Join(testDbRoot, dbName+".ver")
db.Sync()
db.Close()
os.RemoveAll(dbPath)
os.Remove(dbVersionPath)
os.RemoveAll(testDbRoot)
}
}
// Insert the main network genesis block. This is part of the initial
// database setup.
genesisBlock := btcutil.NewBlock(btcnet.MainNetParams.GenesisBlock)
_, err := db.InsertBlock(genesisBlock)
if err != nil {
teardown()
err := fmt.Errorf("failed to insert genesis block: %v", err)
return nil, nil, err
}
chain := blockchain.New(db, &btcnet.MainNetParams, nil)
return chain, teardown, nil
}
// loadTxStore returns a transaction store loaded from a file.
func loadTxStore(filename string) (blockchain.TxStore, error) {
// The txstore file format is:
// <num tx data entries> <tx length> <serialized tx> <blk height>
// <num spent bits> <spent bits>
//
// All num and length fields are little-endian uint32s. The spent bits
// field is padded to a byte boundary.
filename = filepath.Join("testdata/", filename)
fi, err := os.Open(filename)
if err != nil {
return nil, err
}
// Choose read based on whether the file is compressed or not.
var r io.Reader
if strings.HasSuffix(filename, ".bz2") {
r = bzip2.NewReader(fi)
} else {
r = fi
}
defer fi.Close()
// Num of transaction store objects.
var numItems uint32
if err := binary.Read(r, binary.LittleEndian, &numItems); err != nil {
return nil, err
}
txStore := make(blockchain.TxStore)
var uintBuf uint32
for height := uint32(0); height < numItems; height++ {
txD := blockchain.TxData{}
// Serialized transaction length.
err = binary.Read(r, binary.LittleEndian, &uintBuf)
if err != nil {
return nil, err
}
serializedTxLen := uintBuf
if serializedTxLen > btcwire.MaxBlockPayload {
return nil, fmt.Errorf("Read serialized transaction "+
"length of %d is larger max allowed %d",
serializedTxLen, btcwire.MaxBlockPayload)
}
// Transaction.
var msgTx btcwire.MsgTx
err = msgTx.Deserialize(r)
if err != nil {
return nil, err
}
txD.Tx = btcutil.NewTx(&msgTx)
// Transaction hash.
txHash, err := msgTx.TxSha()
if err != nil {
return nil, err
}
txD.Hash = &txHash
// Block height the transaction came from.
err = binary.Read(r, binary.LittleEndian, &uintBuf)
if err != nil {
return nil, err
}
txD.BlockHeight = int64(uintBuf)
// Num spent bits.
err = binary.Read(r, binary.LittleEndian, &uintBuf)
if err != nil {
return nil, err
}
numSpentBits := uintBuf
numSpentBytes := numSpentBits / 8
if numSpentBits%8 != 0 {
numSpentBytes++
}
// Packed spent bytes.
spentBytes := make([]byte, numSpentBytes)
_, err = io.ReadFull(r, spentBytes)
if err != nil {
return nil, err
}
// Populate spent data based on spent bits.
txD.Spent = make([]bool, numSpentBits)
for byteNum, spentByte := range spentBytes {
for bit := 0; bit < 8; bit++ {
if uint32((byteNum*8)+bit) < numSpentBits {
if spentByte&(1<<uint(bit)) != 0 {
txD.Spent[(byteNum*8)+bit] = true
}
}
}
}
txStore[*txD.Hash] = &txD
}
return txStore, nil
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"fmt"
"math/big"
"time"
"github.com/btcsuite/btcwire"
)
const (
// targetTimespan is the desired amount of time that should elapse
// before block difficulty requirement is examined to determine how
// it should be changed in order to maintain the desired block
// generation rate.
targetTimespan = time.Hour * 24 * 14
// targetSpacing is the desired amount of time to generate each block.
targetSpacing = time.Minute * 10
// BlocksPerRetarget is the number of blocks between each difficulty
// retarget. It is calculated based on the desired block generation
// rate.
BlocksPerRetarget = int64(targetTimespan / targetSpacing)
// retargetAdjustmentFactor is the adjustment factor used to limit
// the minimum and maximum amount of adjustment that can occur between
// difficulty retargets.
retargetAdjustmentFactor = 4
// minRetargetTimespan is the minimum amount of adjustment that can
// occur between difficulty retargets. It equates to 25% of the
// previous difficulty.
minRetargetTimespan = int64(targetTimespan / retargetAdjustmentFactor)
// maxRetargetTimespan is the maximum amount of adjustment that can
// occur between difficulty retargets. It equates to 400% of the
// previous difficulty.
maxRetargetTimespan = int64(targetTimespan * retargetAdjustmentFactor)
)
var (
// bigOne is 1 represented as a big.Int. It is defined here to avoid
// the overhead of creating it multiple times.
bigOne = big.NewInt(1)
// oneLsh256 is 1 shifted left 256 bits. It is defined here to avoid
// the overhead of creating it multiple times.
oneLsh256 = new(big.Int).Lsh(bigOne, 256)
)
// ShaHashToBig converts a btcwire.ShaHash into a big.Int that can be used to
// perform math comparisons.
func ShaHashToBig(hash *btcwire.ShaHash) *big.Int {
// A ShaHash is in little-endian, but the big package wants the bytes
// in big-endian. Reverse them. ShaHash.Bytes makes a copy, so it
// is safe to modify the returned buffer.
buf := hash.Bytes()
blen := len(buf)
for i := 0; i < blen/2; i++ {
buf[i], buf[blen-1-i] = buf[blen-1-i], buf[i]
}
return new(big.Int).SetBytes(buf)
}
// CompactToBig converts a compact representation of a whole number N to an
// unsigned 32-bit number. The representation is similar to IEEE754 floating
// point numbers.
//
// Like IEEE754 floating point, there are three basic components: the sign,
// the exponent, and the mantissa. They are broken out as follows:
//
// * the most significant 8 bits represent the unsigned base 256 exponent
// * bit 23 (the 24th bit) represents the sign bit
// * the least significant 23 bits represent the mantissa
//
// -------------------------------------------------
// | Exponent | Sign | Mantissa |
// -------------------------------------------------
// | 8 bits [31-24] | 1 bit [23] | 23 bits [22-00] |
// -------------------------------------------------
//
// The formula to calculate N is:
// N = (-1^sign) * mantissa * 256^(exponent-3)
//
// This compact form is only used in bitcoin to encode unsigned 256-bit numbers
// which represent difficulty targets, thus there really is not a need for a
// sign bit, but it is implemented here to stay consistent with bitcoind.
func CompactToBig(compact uint32) *big.Int {
// Extract the mantissa, sign bit, and exponent.
mantissa := compact & 0x007fffff
isNegative := compact&0x00800000 != 0
exponent := uint(compact >> 24)
// Since the base for the exponent is 256, the exponent can be treated
// as the number of bytes to represent the full 256-bit number. So,
// treat the exponent as the number of bytes and shift the mantissa
// right or left accordingly. This is equivalent to:
// N = mantissa * 256^(exponent-3)
var bn *big.Int
if exponent <= 3 {
mantissa >>= 8 * (3 - exponent)
bn = big.NewInt(int64(mantissa))
} else {
bn = big.NewInt(int64(mantissa))
bn.Lsh(bn, 8*(exponent-3))
}
// Make it negative if the sign bit is set.
if isNegative {
bn = bn.Neg(bn)
}
return bn
}
// BigToCompact converts a whole number N to a compact representation using
// an unsigned 32-bit number. The compact representation only provides 23 bits
// of precision, so values larger than (2^23 - 1) only encode the most
// significant digits of the number. See CompactToBig for details.
func BigToCompact(n *big.Int) uint32 {
// No need to do any work if it's zero.
if n.Sign() == 0 {
return 0
}
// Since the base for the exponent is 256, the exponent can be treated
// as the number of bytes. So, shift the number right or left
// accordingly. This is equivalent to:
// mantissa = mantissa / 256^(exponent-3)
var mantissa uint32
exponent := uint(len(n.Bytes()))
if exponent <= 3 {
mantissa = uint32(n.Bits()[0])
mantissa <<= 8 * (3 - exponent)
} else {
// Use a copy to avoid modifying the caller's original number.
tn := new(big.Int).Set(n)
mantissa = uint32(tn.Rsh(tn, 8*(exponent-3)).Bits()[0])
}
// When the mantissa already has the sign bit set, the number is too
// large to fit into the available 23-bits, so divide the number by 256
// and increment the exponent accordingly.
if mantissa&0x00800000 != 0 {
mantissa >>= 8
exponent++
}
// Pack the exponent, sign bit, and mantissa into an unsigned 32-bit
// int and return it.
compact := uint32(exponent<<24) | mantissa
if n.Sign() < 0 {
compact |= 0x00800000
}
return compact
}
// CalcWork calculates a work value from difficulty bits. Bitcoin increases
// the difficulty for generating a block by decreasing the value which the
// generated hash must be less than. This difficulty target is stored in each
// block header using a compact representation as described in the documenation
// for CompactToBig. The main chain is selected by choosing the chain that has
// the most proof of work (highest difficulty). Since a lower target difficulty
// value equates to higher actual difficulty, the work value which will be
// accumulated must be the inverse of the difficulty. Also, in order to avoid
// potential division by zero and really small floating point numbers, the
// result adds 1 to the denominator and multiplies the numerator by 2^256.
func CalcWork(bits uint32) *big.Int {
// Return a work value of zero if the passed difficulty bits represent
// a negative number. Note this should not happen in practice with valid
// blocks, but an invalid block could trigger it.
difficultyNum := CompactToBig(bits)
if difficultyNum.Sign() <= 0 {
return big.NewInt(0)
}
// (1 << 256) / (difficultyNum + 1)
denominator := new(big.Int).Add(difficultyNum, bigOne)
return new(big.Int).Div(oneLsh256, denominator)
}
// calcEasiestDifficulty calculates the easiest possible difficulty that a block
// can have given starting difficulty bits and a duration. It is mainly used to
// verify that claimed proof of work by a block is sane as compared to a
// known good checkpoint.
func (b *BlockChain) calcEasiestDifficulty(bits uint32, duration time.Duration) uint32 {
// Convert types used in the calculations below.
durationVal := int64(duration)
adjustmentFactor := big.NewInt(retargetAdjustmentFactor)
// The test network rules allow minimum difficulty blocks after more
// than twice the desired amount of time needed to generate a block has
// elapsed.
if b.netParams.ResetMinDifficulty {
if durationVal > int64(targetSpacing)*2 {
return b.netParams.PowLimitBits
}
}
// Since easier difficulty equates to higher numbers, the easiest
// difficulty for a given duration is the largest value possible given
// the number of retargets for the duration and starting difficulty
// multiplied by the max adjustment factor.
newTarget := CompactToBig(bits)
for durationVal > 0 && newTarget.Cmp(b.netParams.PowLimit) < 0 {
newTarget.Mul(newTarget, adjustmentFactor)
durationVal -= maxRetargetTimespan
}
// Limit new value to the proof of work limit.
if newTarget.Cmp(b.netParams.PowLimit) > 0 {
newTarget.Set(b.netParams.PowLimit)
}
return BigToCompact(newTarget)
}
// findPrevTestNetDifficulty returns the difficulty of the previous block which
// did not have the special testnet minimum difficulty rule applied.
func (b *BlockChain) findPrevTestNetDifficulty(startNode *blockNode) (uint32, error) {
// Search backwards through the chain for the last block without
// the special rule applied.
iterNode := startNode
for iterNode != nil && iterNode.height%BlocksPerRetarget != 0 &&
iterNode.bits == b.netParams.PowLimitBits {
// Get the previous block node. This function is used over
// simply accessing iterNode.parent directly as it will
// dynamically create previous block nodes as needed. This
// helps allow only the pieces of the chain that are needed
// to remain in memory.
var err error
iterNode, err = b.getPrevNodeFromNode(iterNode)
if err != nil {
log.Errorf("getPrevNodeFromNode: %v", err)
return 0, err
}
}
// Return the found difficulty or the minimum difficulty if no
// appropriate block was found.
lastBits := b.netParams.PowLimitBits
if iterNode != nil {
lastBits = iterNode.bits
}
return lastBits, nil
}
// calcNextRequiredDifficulty calculates the required difficulty for the block
// after the passed previous block node based on the difficulty retarget rules.
// This function differs from the exported CalcNextRequiredDifficulty in that
// the exported version uses the current best chain as the previous block node
// while this function accepts any block node.
func (b *BlockChain) calcNextRequiredDifficulty(lastNode *blockNode, newBlockTime time.Time) (uint32, error) {
// Genesis block.
if lastNode == nil {
return b.netParams.PowLimitBits, nil
}
// Return the previous block's difficulty requirements if this block
// is not at a difficulty retarget interval.
if (lastNode.height+1)%BlocksPerRetarget != 0 {
// The test network rules allow minimum difficulty blocks after
// more than twice the desired amount of time needed to generate
// a block has elapsed.
if b.netParams.ResetMinDifficulty {
// Return minimum difficulty when more than twice the
// desired amount of time needed to generate a block has
// elapsed.
allowMinTime := lastNode.timestamp.Add(targetSpacing * 2)
if newBlockTime.After(allowMinTime) {
return b.netParams.PowLimitBits, nil
}
// The block was mined within the desired timeframe, so
// return the difficulty for the last block which did
// not have the special minimum difficulty rule applied.
prevBits, err := b.findPrevTestNetDifficulty(lastNode)
if err != nil {
return 0, err
}
return prevBits, nil
}
// For the main network (or any unrecognized networks), simply
// return the previous block's difficulty requirements.
return lastNode.bits, nil
}
// Get the block node at the previous retarget (targetTimespan days
// worth of blocks).
firstNode := lastNode
for i := int64(0); i < BlocksPerRetarget-1 && firstNode != nil; i++ {
// Get the previous block node. This function is used over
// simply accessing firstNode.parent directly as it will
// dynamically create previous block nodes as needed. This
// helps allow only the pieces of the chain that are needed
// to remain in memory.
var err error
firstNode, err = b.getPrevNodeFromNode(firstNode)
if err != nil {
return 0, err
}
}
if firstNode == nil {
return 0, fmt.Errorf("unable to obtain previous retarget block")
}
// Limit the amount of adjustment that can occur to the previous
// difficulty.
actualTimespan := lastNode.timestamp.UnixNano() - firstNode.timestamp.UnixNano()
adjustedTimespan := actualTimespan
if actualTimespan < minRetargetTimespan {
adjustedTimespan = minRetargetTimespan
} else if actualTimespan > maxRetargetTimespan {
adjustedTimespan = maxRetargetTimespan
}
// Calculate new target difficulty as:
// currentDifficulty * (adjustedTimespan / targetTimespan)
// The result uses integer division which means it will be slightly
// rounded down. Bitcoind also uses integer division to calculate this
// result.
oldTarget := CompactToBig(lastNode.bits)
newTarget := new(big.Int).Mul(oldTarget, big.NewInt(adjustedTimespan))
newTarget.Div(newTarget, big.NewInt(int64(targetTimespan)))
// Limit new value to the proof of work limit.
if newTarget.Cmp(b.netParams.PowLimit) > 0 {
newTarget.Set(b.netParams.PowLimit)
}
// Log new target difficulty and return it. The new target logging is
// intentionally converting the bits back to a number instead of using
// newTarget since conversion to the compact representation loses
// precision.
newTargetBits := BigToCompact(newTarget)
log.Debugf("Difficulty retarget at block height %d", lastNode.height+1)
log.Debugf("Old target %08x (%064x)", lastNode.bits, oldTarget)
log.Debugf("New target %08x (%064x)", newTargetBits, CompactToBig(newTargetBits))
log.Debugf("Actual timespan %v, adjusted timespan %v, target timespan %v",
time.Duration(actualTimespan), time.Duration(adjustedTimespan),
targetTimespan)
return newTargetBits, nil
}
// CalcNextRequiredDifficulty calculates the required difficulty for the block
// after the end of the current best chain based on the difficulty retarget
// rules.
//
// This function is NOT safe for concurrent access.
func (b *BlockChain) CalcNextRequiredDifficulty(timestamp time.Time) (uint32, error) {
return b.calcNextRequiredDifficulty(b.bestChain, timestamp)
}

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// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"math/big"
"testing"
"github.com/btcsuite/btcd/blockchain"
)
func TestBigToCompact(t *testing.T) {
tests := []struct {
in int64
out uint32
}{
{0, 0},
{-1, 25231360},
}
for x, test := range tests {
n := big.NewInt(test.in)
r := blockchain.BigToCompact(n)
if r != test.out {
t.Errorf("TestBigToCompact test #%d failed: got %d want %d\n",
x, r, test.out)
return
}
}
}
func TestCompactToBig(t *testing.T) {
tests := []struct {
in uint32
out int64
}{
{10000000, 0},
}
for x, test := range tests {
n := blockchain.CompactToBig(test.in)
want := big.NewInt(test.out)
if n.Cmp(want) != 0 {
t.Errorf("TestCompactToBig test #%d failed: got %d want %d\n",
x, n.Int64(), want.Int64())
return
}
}
}
func TestCalcWork(t *testing.T) {
tests := []struct {
in uint32
out int64
}{
{10000000, 0},
}
for x, test := range tests {
bits := uint32(test.in)
r := blockchain.CalcWork(bits)
if r.Int64() != test.out {
t.Errorf("TestCalcWork test #%d failed: got %v want %d\n",
x, r.Int64(), test.out)
return
}
}
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
/*
Package blockchain implements bitcoin block handling and chain selection rules.
The bitcoin block handling and chain selection rules are an integral, and quite
likely the most important, part of bitcoin. Unfortunately, at the time of
this writing, these rules are also largely undocumented and had to be
ascertained from the bitcoind source code. At its core, bitcoin is a
distributed consensus of which blocks are valid and which ones will comprise the
main block chain (public ledger) that ultimately determines accepted
transactions, so it is extremely important that fully validating nodes agree on
all rules.
At a high level, this package provides support for inserting new blocks into
the block chain according to the aforementioned rules. It includes
functionality such as rejecting duplicate blocks, ensuring blocks and
transactions follow all rules, orphan handling, and best chain selection along
with reorganization.
Since this package does not deal with other bitcoin specifics such as network
communication or wallets, it provides a notification system which gives the
caller a high level of flexibility in how they want to react to certain events
such as orphan blocks which need their parents requested and newly connected
main chain blocks which might result in wallet updates.
Bitcoin Chain Processing Overview
Before a block is allowed into the block chain, it must go through an intensive
series of validation rules. The following list serves as a general outline of
those rules to provide some intuition into what is going on under the hood, but
is by no means exhaustive:
- Reject duplicate blocks
- Perform a series of sanity checks on the block and its transactions such as
verifying proof of work, timestamps, number and character of transactions,
transaction amounts, script complexity, and merkle root calculations
- Compare the block against predetermined checkpoints for expected timestamps
and difficulty based on elapsed time since the checkpoint
- Save the most recent orphan blocks for a limited time in case their parent
blocks become available
- Stop processing if the block is an orphan as the rest of the processing
depends on the block's position within the block chain
- Perform a series of more thorough checks that depend on the block's position
within the block chain such as verifying block difficulties adhere to
difficulty retarget rules, timestamps are after the median of the last
several blocks, all transactions are finalized, checkpoint blocks match, and
block versions are in line with the previous blocks
- Determine how the block fits into the chain and perform different actions
accordingly in order to ensure any side chains which have higher difficulty
than the main chain become the new main chain
- When a block is being connected to the main chain (either through
reorganization of a side chain to the main chain or just extending the
main chain), perform further checks on the block's transactions such as
verifying transaction duplicates, script complexity for the combination of
connected scripts, coinbase maturity, double spends, and connected
transaction values
- Run the transaction scripts to verify the spender is allowed to spend the
coins
- Insert the block into the block database
Errors
Errors returned by this package are either the raw errors provided by underlying
calls or of type blockchain.RuleError. This allows the caller to differentiate
between unexpected errors, such as database errors, versus errors due to rule
violations through type assertions. In addition, callers can programmatically
determine the specific rule violation by examining the ErrorCode field of the
type asserted blockchain.RuleError.
Bitcoin Improvement Proposals
This package includes spec changes outlined by the following BIPs:
BIP0016 (https://en.bitcoin.it/wiki/BIP_0016)
BIP0030 (https://en.bitcoin.it/wiki/BIP_0030)
BIP0034 (https://en.bitcoin.it/wiki/BIP_0034)
*/
package blockchain

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// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"fmt"
)
// ErrorCode identifies a kind of error.
type ErrorCode int
// These constants are used to identify a specific RuleError.
const (
// ErrDuplicateBlock indicates a block with the same hash already
// exists.
ErrDuplicateBlock ErrorCode = iota
// ErrBlockTooBig indicates the serialized block size exceeds the
// maximum allowed size.
ErrBlockTooBig
// ErrBlockVersionTooOld indicates the block version is too old and is
// no longer accepted since the majority of the network has upgraded
// to a newer version.
ErrBlockVersionTooOld
// ErrInvalidTime indicates the time in the passed block has a precision
// that is more than one second. The chain consensus rules require
// timestamps to have a maximum precision of one second.
ErrInvalidTime
// ErrTimeTooOld indicates the time is either before the median time of
// the last several blocks per the chain consensus rules or prior to the
// most recent checkpoint.
ErrTimeTooOld
// ErrTimeTooNew indicates the time is too far in the future as compared
// the current time.
ErrTimeTooNew
// ErrDifficultyTooLow indicates the difficulty for the block is lower
// than the difficulty required by the most recent checkpoint.
ErrDifficultyTooLow
// ErrUnexpectedDifficulty indicates specified bits do not align with
// the expected value either because it doesn't match the calculated
// valued based on difficulty regarted rules or it is out of the valid
// range.
ErrUnexpectedDifficulty
// ErrHighHash indicates the block does not hash to a value which is
// lower than the required target difficultly.
ErrHighHash
// ErrBadMerkleRoot indicates the calculated merkle root does not match
// the expected value.
ErrBadMerkleRoot
// ErrBadCheckpoint indicates a block that is expected to be at a
// checkpoint height does not match the expected one.
ErrBadCheckpoint
// ErrForkTooOld indicates a block is attempting to fork the block chain
// before the most recent checkpoint.
ErrForkTooOld
// ErrCheckpointTimeTooOld indicates a block has a timestamp before the
// most recent checkpoint.
ErrCheckpointTimeTooOld
// ErrNoTransactions indicates the block does not have a least one
// transaction. A valid block must have at least the coinbase
// transaction.
ErrNoTransactions
// ErrTooManyTransactions indicates the block has more transactions than
// are allowed.
ErrTooManyTransactions
// ErrNoTxInputs indicates a transaction does not have any inputs. A
// valid transaction must have at least one input.
ErrNoTxInputs
// ErrNoTxOutputs indicates a transaction does not have any outputs. A
// valid transaction must have at least one output.
ErrNoTxOutputs
// ErrTxTooBig indicates a transaction exceeds the maximum allowed size
// when serialized.
ErrTxTooBig
// ErrBadTxOutValue indicates an output value for a transaction is
// invalid in some way such as being out of range.
ErrBadTxOutValue
// ErrDuplicateTxInputs indicates a transaction references the same
// input more than once.
ErrDuplicateTxInputs
// ErrBadTxInput indicates a transaction input is invalid in some way
// such as referencing a previous transaction outpoint which is out of
// range or not referencing one at all.
ErrBadTxInput
// ErrMissingTx indicates a transaction referenced by an input is
// missing.
ErrMissingTx
// ErrUnfinalizedTx indicates a transaction has not been finalized.
// A valid block may only contain finalized transactions.
ErrUnfinalizedTx
// ErrDuplicateTx indicates a block contains an identical transaction
// (or at least two transactions which hash to the same value). A
// valid block may only contain unique transactions.
ErrDuplicateTx
// ErrOverwriteTx indicates a block contains a transaction that has
// the same hash as a previous transaction which has not been fully
// spent.
ErrOverwriteTx
// ErrImmatureSpend indicates a transaction is attempting to spend a
// coinbase that has not yet reached the required maturity.
ErrImmatureSpend
// ErrDoubleSpend indicates a transaction is attempting to spend coins
// that have already been spent.
ErrDoubleSpend
// ErrSpendTooHigh indicates a transaction is attempting to spend more
// value than the sum of all of its inputs.
ErrSpendTooHigh
// ErrBadFees indicates the total fees for a block are invalid due to
// exceeding the maximum possible value.
ErrBadFees
// ErrTooManySigOps indicates the total number of signature operations
// for a transaction or block exceed the maximum allowed limits.
ErrTooManySigOps
// ErrFirstTxNotCoinbase indicates the first transaction in a block
// is not a coinbase transaction.
ErrFirstTxNotCoinbase
// ErrMultipleCoinbases indicates a block contains more than one
// coinbase transaction.
ErrMultipleCoinbases
// ErrBadCoinbaseScriptLen indicates the length of the signature script
// for a coinbase transaction is not within the valid range.
ErrBadCoinbaseScriptLen
// ErrBadCoinbaseValue indicates the amount of a coinbase value does
// not match the expected value of the subsidy plus the sum of all fees.
ErrBadCoinbaseValue
// ErrMissingCoinbaseHeight indicates the coinbase transaction for a
// block does not start with the serialized block block height as
// required for version 2 and higher blocks.
ErrMissingCoinbaseHeight
// ErrBadCoinbaseHeight indicates the serialized block height in the
// coinbase transaction for version 2 and higher blocks does not match
// the expected value.
ErrBadCoinbaseHeight
// ErrScriptMalformed indicates a transaction script is malformed in
// some way. For example, it might be longer than the maximum allowed
// length or fail to parse.
ErrScriptMalformed
// ErrScriptValidation indicates the result of executing transaction
// script failed. The error covers any failure when executing scripts
// such signature verification failures and execution past the end of
// the stack.
ErrScriptValidation
)
// Map of ErrorCode values back to their constant names for pretty printing.
var errorCodeStrings = map[ErrorCode]string{
ErrDuplicateBlock: "ErrDuplicateBlock",
ErrBlockTooBig: "ErrBlockTooBig",
ErrBlockVersionTooOld: "ErrBlockVersionTooOld",
ErrInvalidTime: "ErrInvalidTime",
ErrTimeTooOld: "ErrTimeTooOld",
ErrTimeTooNew: "ErrTimeTooNew",
ErrDifficultyTooLow: "ErrDifficultyTooLow",
ErrUnexpectedDifficulty: "ErrUnexpectedDifficulty",
ErrHighHash: "ErrHighHash",
ErrBadMerkleRoot: "ErrBadMerkleRoot",
ErrBadCheckpoint: "ErrBadCheckpoint",
ErrForkTooOld: "ErrForkTooOld",
ErrCheckpointTimeTooOld: "ErrCheckpointTimeTooOld",
ErrNoTransactions: "ErrNoTransactions",
ErrTooManyTransactions: "ErrTooManyTransactions",
ErrNoTxInputs: "ErrNoTxInputs",
ErrNoTxOutputs: "ErrNoTxOutputs",
ErrTxTooBig: "ErrTxTooBig",
ErrBadTxOutValue: "ErrBadTxOutValue",
ErrDuplicateTxInputs: "ErrDuplicateTxInputs",
ErrBadTxInput: "ErrBadTxInput",
ErrMissingTx: "ErrMissingTx",
ErrUnfinalizedTx: "ErrUnfinalizedTx",
ErrDuplicateTx: "ErrDuplicateTx",
ErrOverwriteTx: "ErrOverwriteTx",
ErrImmatureSpend: "ErrImmatureSpend",
ErrDoubleSpend: "ErrDoubleSpend",
ErrSpendTooHigh: "ErrSpendTooHigh",
ErrBadFees: "ErrBadFees",
ErrTooManySigOps: "ErrTooManySigOps",
ErrFirstTxNotCoinbase: "ErrFirstTxNotCoinbase",
ErrMultipleCoinbases: "ErrMultipleCoinbases",
ErrBadCoinbaseScriptLen: "ErrBadCoinbaseScriptLen",
ErrBadCoinbaseValue: "ErrBadCoinbaseValue",
ErrMissingCoinbaseHeight: "ErrMissingCoinbaseHeight",
ErrBadCoinbaseHeight: "ErrBadCoinbaseHeight",
ErrScriptMalformed: "ErrScriptMalformed",
ErrScriptValidation: "ErrScriptValidation",
}
// String returns the ErrorCode as a human-readable name.
func (e ErrorCode) String() string {
if s := errorCodeStrings[e]; s != "" {
return s
}
return fmt.Sprintf("Unknown ErrorCode (%d)", int(e))
}
// RuleError identifies a rule violation. It is used to indicate that
// processing of a block or transaction failed due to one of the many validation
// rules. The caller can use type assertions to determine if a failure was
// specifically due to a rule violation and access the ErrorCode field to
// ascertain the specific reason for the rule violation.
type RuleError struct {
ErrorCode ErrorCode // Describes the kind of error
Description string // Human readable description of the issue
}
// Error satisfies the error interface and prints human-readable errors.
func (e RuleError) Error() string {
return e.Description
}
// ruleError creates an RuleError given a set of arguments.
func ruleError(c ErrorCode, desc string) RuleError {
return RuleError{ErrorCode: c, Description: desc}
}

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// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"testing"
"github.com/btcsuite/btcd/blockchain"
)
// TestErrorCodeStringer tests the stringized output for the ErrorCode type.
func TestErrorCodeStringer(t *testing.T) {
tests := []struct {
in blockchain.ErrorCode
want string
}{
{blockchain.ErrDuplicateBlock, "ErrDuplicateBlock"},
{blockchain.ErrBlockTooBig, "ErrBlockTooBig"},
{blockchain.ErrBlockVersionTooOld, "ErrBlockVersionTooOld"},
{blockchain.ErrInvalidTime, "ErrInvalidTime"},
{blockchain.ErrTimeTooOld, "ErrTimeTooOld"},
{blockchain.ErrTimeTooNew, "ErrTimeTooNew"},
{blockchain.ErrDifficultyTooLow, "ErrDifficultyTooLow"},
{blockchain.ErrUnexpectedDifficulty, "ErrUnexpectedDifficulty"},
{blockchain.ErrHighHash, "ErrHighHash"},
{blockchain.ErrBadMerkleRoot, "ErrBadMerkleRoot"},
{blockchain.ErrBadCheckpoint, "ErrBadCheckpoint"},
{blockchain.ErrForkTooOld, "ErrForkTooOld"},
{blockchain.ErrCheckpointTimeTooOld, "ErrCheckpointTimeTooOld"},
{blockchain.ErrNoTransactions, "ErrNoTransactions"},
{blockchain.ErrTooManyTransactions, "ErrTooManyTransactions"},
{blockchain.ErrNoTxInputs, "ErrNoTxInputs"},
{blockchain.ErrNoTxOutputs, "ErrNoTxOutputs"},
{blockchain.ErrTxTooBig, "ErrTxTooBig"},
{blockchain.ErrBadTxOutValue, "ErrBadTxOutValue"},
{blockchain.ErrDuplicateTxInputs, "ErrDuplicateTxInputs"},
{blockchain.ErrBadTxInput, "ErrBadTxInput"},
{blockchain.ErrBadCheckpoint, "ErrBadCheckpoint"},
{blockchain.ErrMissingTx, "ErrMissingTx"},
{blockchain.ErrUnfinalizedTx, "ErrUnfinalizedTx"},
{blockchain.ErrDuplicateTx, "ErrDuplicateTx"},
{blockchain.ErrOverwriteTx, "ErrOverwriteTx"},
{blockchain.ErrImmatureSpend, "ErrImmatureSpend"},
{blockchain.ErrDoubleSpend, "ErrDoubleSpend"},
{blockchain.ErrSpendTooHigh, "ErrSpendTooHigh"},
{blockchain.ErrBadFees, "ErrBadFees"},
{blockchain.ErrTooManySigOps, "ErrTooManySigOps"},
{blockchain.ErrFirstTxNotCoinbase, "ErrFirstTxNotCoinbase"},
{blockchain.ErrMultipleCoinbases, "ErrMultipleCoinbases"},
{blockchain.ErrBadCoinbaseScriptLen, "ErrBadCoinbaseScriptLen"},
{blockchain.ErrBadCoinbaseValue, "ErrBadCoinbaseValue"},
{blockchain.ErrMissingCoinbaseHeight, "ErrMissingCoinbaseHeight"},
{blockchain.ErrBadCoinbaseHeight, "ErrBadCoinbaseHeight"},
{blockchain.ErrScriptMalformed, "ErrScriptMalformed"},
{blockchain.ErrScriptValidation, "ErrScriptValidation"},
{0xffff, "Unknown ErrorCode (65535)"},
}
t.Logf("Running %d tests", len(tests))
for i, test := range tests {
result := test.in.String()
if result != test.want {
t.Errorf("String #%d\n got: %s want: %s", i, result,
test.want)
continue
}
}
}
// TestRuleError tests the error output for the RuleError type.
func TestRuleError(t *testing.T) {
tests := []struct {
in blockchain.RuleError
want string
}{
{
blockchain.RuleError{Description: "duplicate block"},
"duplicate block",
},
{
blockchain.RuleError{Description: "human-readable error"},
"human-readable error",
},
}
t.Logf("Running %d tests", len(tests))
for i, test := range tests {
result := test.in.Error()
if result != test.want {
t.Errorf("Error #%d\n got: %s want: %s", i, result,
test.want)
continue
}
}
}

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// Copyright (c) 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"fmt"
"math/big"
"github.com/btcsuite/btcd/blockchain"
"github.com/btcsuite/btcd/database"
_ "github.com/btcsuite/btcd/database/memdb"
"github.com/btcsuite/btcnet"
"github.com/btcsuite/btcutil"
)
// This example demonstrates how to create a new chain instance and use
// ProcessBlock to attempt to attempt add a block to the chain. As the package
// overview documentation describes, this includes all of the Bitcoin consensus
// rules. This example intentionally attempts to insert a duplicate genesis
// block to illustrate how an invalid block is handled.
func ExampleBlockChain_ProcessBlock() {
// Create a new database to store the accepted blocks into. Typically
// this would be opening an existing database and would not use memdb
// which is a memory-only database backend, but we create a new db
// here so this is a complete working example.
db, err := database.CreateDB("memdb")
if err != nil {
fmt.Printf("Failed to create database: %v\n", err)
return
}
defer db.Close()
// Insert the main network genesis block. This is part of the initial
// database setup. Like above, this typically would not be needed when
// opening an existing database.
genesisBlock := btcutil.NewBlock(btcnet.MainNetParams.GenesisBlock)
_, err = db.InsertBlock(genesisBlock)
if err != nil {
fmt.Printf("Failed to insert genesis block: %v\n", err)
return
}
// Create a new BlockChain instance using the underlying database for
// the main bitcoin network and ignore notifications.
chain := blockchain.New(db, &btcnet.MainNetParams, nil)
// Create a new median time source that is required by the upcoming
// call to ProcessBlock. Ordinarily this would also add time values
// obtained from other peers on the network so the local time is
// adjusted to be in agreement with other peers.
timeSource := blockchain.NewMedianTime()
// Process a block. For this example, we are going to intentionally
// cause an error by trying to process the genesis block which already
// exists.
isOrphan, err := chain.ProcessBlock(genesisBlock, timeSource, blockchain.BFNone)
if err != nil {
fmt.Printf("Failed to process block: %v\n", err)
return
}
fmt.Printf("Block accepted. Is it an orphan?: %v", isOrphan)
// Output:
// Failed to process block: already have block 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
}
// This example demonstrates how to convert the compact "bits" in a block header
// which represent the target difficulty to a big integer and display it using
// the typical hex notation.
func ExampleCompactToBig() {
// Convert the bits from block 300000 in the main block chain.
bits := uint32(419465580)
targetDifficulty := blockchain.CompactToBig(bits)
// Display it in hex.
fmt.Printf("%064x\n", targetDifficulty.Bytes())
// Output:
// 0000000000000000896c00000000000000000000000000000000000000000000
}
// This example demonstrates how to convert a target difficulty into the compact
// "bits" in a block header which represent that target difficulty .
func ExampleBigToCompact() {
// Convert the target difficulty from block 300000 in the main block
// chain to compact form.
t := "0000000000000000896c00000000000000000000000000000000000000000000"
targetDifficulty, success := new(big.Int).SetString(t, 16)
if !success {
fmt.Println("invalid target difficulty")
return
}
bits := blockchain.BigToCompact(targetDifficulty)
fmt.Println(bits)
// Output:
// 419465580
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
/*
This test file is part of the blockchain package rather than than the
blockchain_test package so it can bridge access to the internals to properly
test cases which are either not possible or can't reliably be tested via the
public interface. The functions are only exported while the tests are being
run.
*/
package blockchain
import (
"sort"
"time"
)
// TstSetCoinbaseMaturity makes the ability to set the coinbase maturity
// available to the test package.
func TstSetCoinbaseMaturity(maturity int64) {
coinbaseMaturity = maturity
}
// TstTimeSorter makes the internal timeSorter type available to the test
// package.
func TstTimeSorter(times []time.Time) sort.Interface {
return timeSorter(times)
}
// TstCheckSerializedHeight makes the internal checkSerializedHeight function
// available to the test package.
var TstCheckSerializedHeight = checkSerializedHeight
// TstSetMaxMedianTimeEntries makes the ability to set the maximum number of
// median tiem entries available to the test package.
func TstSetMaxMedianTimeEntries(val int) {
maxMedianTimeEntries = val
}
// TstCheckBlockScripts makes the internal checkBlockScripts function available
// to the test package.
var TstCheckBlockScripts = checkBlockScripts

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"errors"
"io"
"github.com/btcsuite/btclog"
)
// log is a logger that is initialized with no output filters. This
// means the package will not perform any logging by default until the caller
// requests it.
var log btclog.Logger
// The default amount of logging is none.
func init() {
DisableLog()
}
// DisableLog disables all library log output. Logging output is disabled
// by default until either UseLogger or SetLogWriter are called.
func DisableLog() {
log = btclog.Disabled
}
// UseLogger uses a specified Logger to output package logging info.
// This should be used in preference to SetLogWriter if the caller is also
// using btclog.
func UseLogger(logger btclog.Logger) {
log = logger
}
// SetLogWriter uses a specified io.Writer to output package logging info.
// This allows a caller to direct package logging output without needing a
// dependency on seelog. If the caller is also using btclog, UseLogger should
// be used instead.
func SetLogWriter(w io.Writer, level string) error {
if w == nil {
return errors.New("nil writer")
}
lvl, ok := btclog.LogLevelFromString(level)
if !ok {
return errors.New("invalid log level")
}
l, err := btclog.NewLoggerFromWriter(w, lvl)
if err != nil {
return err
}
UseLogger(l)
return nil
}
// LogClosure is a closure that can be printed with %v to be used to
// generate expensive-to-create data for a detailed log level and avoid doing
// the work if the data isn't printed.
type logClosure func() string
func (c logClosure) String() string {
return c()
}
func newLogClosure(c func() string) logClosure {
return logClosure(c)
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"math"
"sort"
"sync"
"time"
)
const (
// maxAllowedOffsetSeconds is the maximum number of seconds in either
// direction that local clock will be adjusted. When the median time
// of the network is outside of this range, no offset will be applied.
maxAllowedOffsetSecs = 70 * 60 // 1 hour 10 minutes
// similarTimeSecs is the number of seconds in either direction from the
// local clock that is used to determine that it is likley wrong and
// hence to show a warning.
similarTimeSecs = 5 * 60 // 5 minutes
)
var (
// maxMedianTimeEntries is the maximum number of entries allowed in the
// median time data. This is a variable as opposed to a constant so the
// test code can modify it.
maxMedianTimeEntries = 200
)
// MedianTimeSource provides a mechanism to add several time samples which are
// used to determine a median time which is then used as an offset to the local
// clock.
type MedianTimeSource interface {
// AdjustedTime returns the current time adjusted by the median time
// offset as calculated from the time samples added by AddTimeSample.
AdjustedTime() time.Time
// AddTimeSample adds a time sample that is used when determining the
// median time of the added samples.
AddTimeSample(id string, timeVal time.Time)
// Offset returns the number of seconds to adjust the local clock based
// upon the median of the time samples added by AddTimeData.
Offset() time.Duration
}
// int64Sorter implements sort.Interface to allow a slice of 64-bit integers to
// be sorted.
type int64Sorter []int64
// Len returns the number of 64-bit integers in the slice. It is part of the
// sort.Interface implementation.
func (s int64Sorter) Len() int {
return len(s)
}
// Swap swaps the 64-bit integers at the passed indices. It is part of the
// sort.Interface implementation.
func (s int64Sorter) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
// Less returns whether the 64-bit integer with index i should sort before the
// 64-bit integer with index j. It is part of the sort.Interface
// implementation.
func (s int64Sorter) Less(i, j int) bool {
return s[i] < s[j]
}
// medianTime provides an implementation of the MedianTimeSource interface.
// It is limited to maxMedianTimeEntries includes the same buggy behavior as
// the time offset mechanism in Bitcoin Core. This is necessary because it is
// used in the consensus code.
type medianTime struct {
mtx sync.Mutex
knownIDs map[string]struct{}
offsets []int64
offsetSecs int64
invalidTimeChecked bool
}
// Ensure the medianTime type implements the MedianTimeSource interface.
var _ MedianTimeSource = (*medianTime)(nil)
// AdjustedTime returns the current time adjusted by the median time offset as
// calculated from the time samples added by AddTimeSample.
//
// This function is safe for concurrent access and is part of the
// MedianTimeSource interface implementation.
func (m *medianTime) AdjustedTime() time.Time {
m.mtx.Lock()
defer m.mtx.Unlock()
// Limit the adjusted time to 1 second precision.
now := time.Unix(time.Now().Unix(), 0)
return now.Add(time.Duration(m.offsetSecs) * time.Second)
}
// AddTimeSample adds a time sample that is used when determining the median
// time of the added samples.
//
// This function is safe for concurrent access and is part of the
// MedianTimeSource interface implementation.
func (m *medianTime) AddTimeSample(sourceID string, timeVal time.Time) {
m.mtx.Lock()
defer m.mtx.Unlock()
// Don't add time data from the same source.
if _, exists := m.knownIDs[sourceID]; exists {
return
}
m.knownIDs[sourceID] = struct{}{}
// Truncate the provided offset to seconds and append it to the slice
// of offsets while respecting the maximum number of allowed entries by
// replacing the oldest entry with the new entry once the maximum number
// of entries is reached.
now := time.Unix(time.Now().Unix(), 0)
offsetSecs := int64(timeVal.Sub(now).Seconds())
numOffsets := len(m.offsets)
if numOffsets == maxMedianTimeEntries && maxMedianTimeEntries > 0 {
m.offsets = m.offsets[1:]
numOffsets--
}
m.offsets = append(m.offsets, offsetSecs)
numOffsets++
// Sort the offsets so the median can be obtained as needed later.
sortedOffsets := make([]int64, numOffsets)
copy(sortedOffsets, m.offsets)
sort.Sort(int64Sorter(sortedOffsets))
offsetDuration := time.Duration(offsetSecs) * time.Second
log.Debugf("Added time sample of %v (total: %v)", offsetDuration,
numOffsets)
// NOTE: The following code intentionally has a bug to mirror the
// buggy behavior in Bitcoin Core since the median time is used in the
// consensus rules.
//
// In particular, the offset is only updated when the number of entries
// is odd, but the max number of entries is 200, an even number. Thus,
// the offset will never be updated again once the max number of entries
// is reached.
// The median offset is only updated when there are enough offsets and
// the number of offsets is odd so the middle value is the true median.
// Thus, there is nothing to do when those conditions are not met.
if numOffsets < 5 || numOffsets&0x01 != 1 {
return
}
// At this point the number of offsets in the list is odd, so the
// middle value of the sorted offsets is the median.
median := sortedOffsets[numOffsets/2]
// Set the new offset when the median offset is within the allowed
// offset range.
if math.Abs(float64(median)) < maxAllowedOffsetSecs {
m.offsetSecs = median
} else {
// The median offset of all added time data is larger than the
// maximum allowed offset, so don't use an offset. This
// effectively limits how far the local clock can be skewed.
m.offsetSecs = 0
if !m.invalidTimeChecked {
m.invalidTimeChecked = true
// Find if any time samples have a time that is close
// to the local time.
var remoteHasCloseTime bool
for _, offset := range sortedOffsets {
if math.Abs(float64(offset)) < similarTimeSecs {
remoteHasCloseTime = true
break
}
}
// Warn if none of the time samples are close.
if !remoteHasCloseTime {
log.Warnf("Please check your date and time " +
"are correct! btcd will not work " +
"properly with an invalid time")
}
}
}
medianDuration := time.Duration(m.offsetSecs) * time.Second
log.Debugf("New time offset: %v", medianDuration)
}
// Offset returns the number of seconds to adjust the local clock based upon the
// median of the time samples added by AddTimeData.
//
// This function is safe for concurrent access and is part of the
// MedianTimeSource interface implementation.
func (m *medianTime) Offset() time.Duration {
m.mtx.Lock()
defer m.mtx.Unlock()
return time.Duration(m.offsetSecs) * time.Second
}
// NewMedianTime returns a new instance of concurrency-safe implementation of
// the MedianTimeSource interface. The returned implementation contains the
// rules necessary for proper time handling in the chain consensus rules and
// expects the time samples to be added from the timestamp field of the version
// message received from remote peers that successfully connect and negotiate.
func NewMedianTime() MedianTimeSource {
return &medianTime{
knownIDs: make(map[string]struct{}),
offsets: make([]int64, 0, maxMedianTimeEntries),
}
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"strconv"
"testing"
"time"
"github.com/btcsuite/btcd/blockchain"
)
// TestMedianTime tests the medianTime implementation.
func TestMedianTime(t *testing.T) {
tests := []struct {
in []int64
wantOffset int64
useDupID bool
}{
// Not enough samples must result in an offset of 0.
{in: []int64{1}, wantOffset: 0},
{in: []int64{1, 2}, wantOffset: 0},
{in: []int64{1, 2, 3}, wantOffset: 0},
{in: []int64{1, 2, 3, 4}, wantOffset: 0},
// Various number of entries. The expected offset is only
// updated on odd number of elements.
{in: []int64{-13, 57, -4, -23, -12}, wantOffset: -12},
{in: []int64{55, -13, 61, -52, 39, 55}, wantOffset: 39},
{in: []int64{-62, -58, -30, -62, 51, -30, 15}, wantOffset: -30},
{in: []int64{29, -47, 39, 54, 42, 41, 8, -33}, wantOffset: 39},
{in: []int64{37, 54, 9, -21, -56, -36, 5, -11, -39}, wantOffset: -11},
{in: []int64{57, -28, 25, -39, 9, 63, -16, 19, -60, 25}, wantOffset: 9},
{in: []int64{-5, -4, -3, -2, -1}, wantOffset: -3, useDupID: true},
// The offset stops being updated once the max number of entries
// has been reached. This is actually a bug from Bitcoin Core,
// but since the time is ultimately used as a part of the
// consensus rules, it must be mirrored.
{in: []int64{-67, 67, -50, 24, 63, 17, 58, -14, 5, -32, -52}, wantOffset: 17},
{in: []int64{-67, 67, -50, 24, 63, 17, 58, -14, 5, -32, -52, 45}, wantOffset: 17},
{in: []int64{-67, 67, -50, 24, 63, 17, 58, -14, 5, -32, -52, 45, 4}, wantOffset: 17},
// Offsets that are too far away from the local time should
// be ignored.
{in: []int64{-4201, 4202, -4203, 4204, -4205}, wantOffset: 0},
// Excerise the condition where the median offset is greater
// than the max allowed adjustment, but there is at least one
// sample that is close enough to the current time to avoid
// triggering a warning about an invalid local clock.
{in: []int64{4201, 4202, 4203, 4204, -299}, wantOffset: 0},
}
// Modify the max number of allowed median time entries for these tests.
blockchain.TstSetMaxMedianTimeEntries(10)
defer blockchain.TstSetMaxMedianTimeEntries(200)
for i, test := range tests {
filter := blockchain.NewMedianTime()
for j, offset := range test.in {
id := strconv.Itoa(j)
now := time.Unix(time.Now().Unix(), 0)
tOffset := now.Add(time.Duration(offset) * time.Second)
filter.AddTimeSample(id, tOffset)
// Ensure the duplicate IDs are ignored.
if test.useDupID {
// Modify the offsets to ensure the final median
// would be different if the duplicate is added.
tOffset = tOffset.Add(time.Duration(offset) *
time.Second)
filter.AddTimeSample(id, tOffset)
}
}
// Since it is possible that the time.Now call in AddTimeSample
// and the time.Now calls here in the tests will be off by one
// second, allow a fudge factor to compensate.
gotOffset := filter.Offset()
wantOffset := time.Duration(test.wantOffset) * time.Second
wantOffset2 := time.Duration(test.wantOffset-1) * time.Second
if gotOffset != wantOffset && gotOffset != wantOffset2 {
t.Errorf("Offset #%d: unexpected offset -- got %v, "+
"want %v or %v", i, gotOffset, wantOffset,
wantOffset2)
continue
}
// Since it is possible that the time.Now call in AdjustedTime
// and the time.Now call here in the tests will be off by one
// second, allow a fudge factor to compensate.
adjustedTime := filter.AdjustedTime()
now := time.Unix(time.Now().Unix(), 0)
wantTime := now.Add(filter.Offset())
wantTime2 := now.Add(filter.Offset() - time.Second)
if !adjustedTime.Equal(wantTime) && !adjustedTime.Equal(wantTime2) {
t.Errorf("AdjustedTime #%d: unexpected result -- got %v, "+
"want %v or %v", i, adjustedTime, wantTime,
wantTime2)
continue
}
}
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"math"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
// nextPowerOfTwo returns the next highest power of two from a given number if
// it is not already a power of two. This is a helper function used during the
// calculation of a merkle tree.
func nextPowerOfTwo(n int) int {
// Return the number if it's already a power of 2.
if n&(n-1) == 0 {
return n
}
// Figure out and return the next power of two.
exponent := uint(math.Log2(float64(n))) + 1
return 1 << exponent // 2^exponent
}
// HashMerkleBranches takes two hashes, treated as the left and right tree
// nodes, and returns the hash of their concatenation. This is a helper
// function used to aid in the generation of a merkle tree.
func HashMerkleBranches(left *btcwire.ShaHash, right *btcwire.ShaHash) *btcwire.ShaHash {
// Concatenate the left and right nodes.
var sha [btcwire.HashSize * 2]byte
copy(sha[:btcwire.HashSize], left.Bytes())
copy(sha[btcwire.HashSize:], right.Bytes())
// Create a new sha hash from the double sha 256. Ignore the error
// here since SetBytes can't fail here due to the fact DoubleSha256
// always returns a []byte of the right size regardless of input.
newSha, _ := btcwire.NewShaHash(btcwire.DoubleSha256(sha[:]))
return newSha
}
// BuildMerkleTreeStore creates a merkle tree from a slice of transactions,
// stores it using a linear array, and returns a slice of the backing array. A
// linear array was chosen as opposed to an actual tree structure since it uses
// about half as much memory. The following describes a merkle tree and how it
// is stored in a linear array.
//
// A merkle tree is a tree in which every non-leaf node is the hash of its
// children nodes. A diagram depicting how this works for bitcoin transactions
// where h(x) is a double sha256 follows:
//
// root = h1234 = h(h12 + h34)
// / \
// h12 = h(h1 + h2) h34 = h(h3 + h4)
// / \ / \
// h1 = h(tx1) h2 = h(tx2) h3 = h(tx3) h4 = h(tx4)
//
// The above stored as a linear array is as follows:
//
// [h1 h2 h3 h4 h12 h34 root]
//
// As the above shows, the merkle root is always the last element in the array.
//
// The number of inputs is not always a power of two which results in a
// balanced tree structure as above. In that case, parent nodes with no
// children are also zero and parent nodes with only a single left node
// are calculated by concatenating the left node with itself before hashing.
// Since this function uses nodes that are pointers to the hashes, empty nodes
// will be nil.
func BuildMerkleTreeStore(transactions []*btcutil.Tx) []*btcwire.ShaHash {
// Calculate how many entries are required to hold the binary merkle
// tree as a linear array and create an array of that size.
nextPoT := nextPowerOfTwo(len(transactions))
arraySize := nextPoT*2 - 1
merkles := make([]*btcwire.ShaHash, arraySize)
// Create the base transaction shas and populate the array with them.
for i, tx := range transactions {
merkles[i] = tx.Sha()
}
// Start the array offset after the last transaction and adjusted to the
// next power of two.
offset := nextPoT
for i := 0; i < arraySize-1; i += 2 {
switch {
// When there is no left child node, the parent is nil too.
case merkles[i] == nil:
merkles[offset] = nil
// When there is no right child, the parent is generated by
// hashing the concatenation of the left child with itself.
case merkles[i+1] == nil:
newSha := HashMerkleBranches(merkles[i], merkles[i])
merkles[offset] = newSha
// The normal case sets the parent node to the double sha256
// of the concatentation of the left and right children.
default:
newSha := HashMerkleBranches(merkles[i], merkles[i+1])
merkles[offset] = newSha
}
offset++
}
return merkles
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"testing"
"github.com/btcsuite/btcd/blockchain"
"github.com/btcsuite/btcutil"
)
// TestMerkle tests the BuildMerkleTreeStore API.
func TestMerkle(t *testing.T) {
block := btcutil.NewBlock(&Block100000)
merkles := blockchain.BuildMerkleTreeStore(block.Transactions())
calculatedMerkleRoot := merkles[len(merkles)-1]
wantMerkle := &Block100000.Header.MerkleRoot
if !wantMerkle.IsEqual(calculatedMerkleRoot) {
t.Errorf("BuildMerkleTreeStore: merkle root mismatch - "+
"got %v, want %v", calculatedMerkleRoot, wantMerkle)
}
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"fmt"
)
// NotificationType represents the type of a notification message.
type NotificationType int
// NotificationCallback is used for a caller to provide a callback for
// notifications about various chain events.
type NotificationCallback func(*Notification)
// Constants for the type of a notification message.
const (
// NTBlockAccepted indicates the associated block was accepted into
// the block chain. Note that this does not necessarily mean it was
// added to the main chain. For that, use NTBlockConnected.
NTBlockAccepted NotificationType = iota
// NTBlockConnected indicates the associated block was connected to the
// main chain.
NTBlockConnected
// NTBlockDisconnected indicates the associated block was disconnected
// from the main chain.
NTBlockDisconnected
)
// notificationTypeStrings is a map of notification types back to their constant
// names for pretty printing.
var notificationTypeStrings = map[NotificationType]string{
NTBlockAccepted: "NTBlockAccepted",
NTBlockConnected: "NTBlockConnected",
NTBlockDisconnected: "NTBlockDisconnected",
}
// String returns the NotificationType in human-readable form.
func (n NotificationType) String() string {
if s, ok := notificationTypeStrings[n]; ok {
return s
}
return fmt.Sprintf("Unknown Notification Type (%d)", int(n))
}
// Notification defines notification that is sent to the caller via the callback
// function provided during the call to New and consists of a notification type
// as well as associated data that depends on the type as follows:
// - NTBlockAccepted: *btcutil.Block
// - NTBlockConnected: *btcutil.Block
// - NTBlockDisconnected: *btcutil.Block
type Notification struct {
Type NotificationType
Data interface{}
}
// sendNotification sends a notification with the passed type and data if the
// caller requested notifications by providing a callback function in the call
// to New.
func (b *BlockChain) sendNotification(typ NotificationType, data interface{}) {
// Ignore it if the caller didn't request notifications.
if b.notifications == nil {
return
}
// Generate and send the notification.
n := Notification{Type: typ, Data: data}
b.notifications(&n)
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"fmt"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
// BehaviorFlags is a bitmask defining tweaks to the normal behavior when
// performing chain processing and consensus rules checks.
type BehaviorFlags uint32
const (
// BFFastAdd may be set to indicate that several checks can be avoided
// for the block since it is already known to fit into the chain due to
// already proving it correct links into the chain up to a known
// checkpoint. This is primarily used for headers-first mode.
BFFastAdd BehaviorFlags = 1 << iota
// BFNoPoWCheck may be set to indicate the proof of work check which
// ensures a block hashes to a value less than the required target will
// not be performed.
BFNoPoWCheck
// BFDryRun may be set to indicate the block should not modify the chain
// or memory chain index. This is useful to test that a block is valid
// without modifying the current state.
BFDryRun
// BFNone is a convenience value to specifically indicate no flags.
BFNone BehaviorFlags = 0
)
// blockExists determines whether a block with the given hash exists either in
// the main chain or any side chains.
func (b *BlockChain) blockExists(hash *btcwire.ShaHash) (bool, error) {
// Check memory chain first (could be main chain or side chain blocks).
if _, ok := b.index[*hash]; ok {
return true, nil
}
// Check in database (rest of main chain not in memory).
return b.db.ExistsSha(hash)
}
// processOrphans determines if there are any orphans which depend on the passed
// block hash (they are no longer orphans if true) and potentially accepts them.
// It repeats the process for the newly accepted blocks (to detect further
// orphans which may no longer be orphans) until there are no more.
//
// The flags do not modify the behavior of this function directly, however they
// are needed to pass along to maybeAcceptBlock.
func (b *BlockChain) processOrphans(hash *btcwire.ShaHash, flags BehaviorFlags) error {
// Start with processing at least the passed hash. Leave a little room
// for additional orphan blocks that need to be processed without
// needing to grow the array in the common case.
processHashes := make([]*btcwire.ShaHash, 0, 10)
processHashes = append(processHashes, hash)
for len(processHashes) > 0 {
// Pop the first hash to process from the slice.
processHash := processHashes[0]
processHashes[0] = nil // Prevent GC leak.
processHashes = processHashes[1:]
// Look up all orphans that are parented by the block we just
// accepted. This will typically only be one, but it could
// be multiple if multiple blocks are mined and broadcast
// around the same time. The one with the most proof of work
// will eventually win out. An indexing for loop is
// intentionally used over a range here as range does not
// reevaluate the slice on each iteration nor does it adjust the
// index for the modified slice.
for i := 0; i < len(b.prevOrphans[*processHash]); i++ {
orphan := b.prevOrphans[*processHash][i]
if orphan == nil {
log.Warnf("Found a nil entry at index %d in the "+
"orphan dependency list for block %v", i,
processHash)
continue
}
// Remove the orphan from the orphan pool.
// It's safe to ignore the error on Sha since the hash
// is already cached.
orphanHash, _ := orphan.block.Sha()
b.removeOrphanBlock(orphan)
i--
// Potentially accept the block into the block chain.
err := b.maybeAcceptBlock(orphan.block, flags)
if err != nil {
return err
}
// Add this block to the list of blocks to process so
// any orphan blocks that depend on this block are
// handled too.
processHashes = append(processHashes, orphanHash)
}
}
return nil
}
// ProcessBlock is the main workhorse for handling insertion of new blocks into
// the block chain. It includes functionality such as rejecting duplicate
// blocks, ensuring blocks follow all rules, orphan handling, and insertion into
// the block chain along with best chain selection and reorganization.
//
// It returns a bool which indicates whether or not the block is an orphan and
// any errors that occurred during processing. The returned bool is only valid
// when the error is nil.
func (b *BlockChain) ProcessBlock(block *btcutil.Block, timeSource MedianTimeSource, flags BehaviorFlags) (bool, error) {
fastAdd := flags&BFFastAdd == BFFastAdd
dryRun := flags&BFDryRun == BFDryRun
blockHash, err := block.Sha()
if err != nil {
return false, err
}
log.Tracef("Processing block %v", blockHash)
// The block must not already exist in the main chain or side chains.
exists, err := b.blockExists(blockHash)
if err != nil {
return false, err
}
if exists {
str := fmt.Sprintf("already have block %v", blockHash)
return false, ruleError(ErrDuplicateBlock, str)
}
// The block must not already exist as an orphan.
if _, exists := b.orphans[*blockHash]; exists {
str := fmt.Sprintf("already have block (orphan) %v", blockHash)
return false, ruleError(ErrDuplicateBlock, str)
}
// Perform preliminary sanity checks on the block and its transactions.
err = checkBlockSanity(block, b.netParams.PowLimit, timeSource, flags)
if err != nil {
return false, err
}
// Find the previous checkpoint and perform some additional checks based
// on the checkpoint. This provides a few nice properties such as
// preventing old side chain blocks before the last checkpoint,
// rejecting easy to mine, but otherwise bogus, blocks that could be
// used to eat memory, and ensuring expected (versus claimed) proof of
// work requirements since the previous checkpoint are met.
blockHeader := &block.MsgBlock().Header
checkpointBlock, err := b.findPreviousCheckpoint()
if err != nil {
return false, err
}
if checkpointBlock != nil {
// Ensure the block timestamp is after the checkpoint timestamp.
checkpointHeader := &checkpointBlock.MsgBlock().Header
checkpointTime := checkpointHeader.Timestamp
if blockHeader.Timestamp.Before(checkpointTime) {
str := fmt.Sprintf("block %v has timestamp %v before "+
"last checkpoint timestamp %v", blockHash,
blockHeader.Timestamp, checkpointTime)
return false, ruleError(ErrCheckpointTimeTooOld, str)
}
if !fastAdd {
// Even though the checks prior to now have already ensured the
// proof of work exceeds the claimed amount, the claimed amount
// is a field in the block header which could be forged. This
// check ensures the proof of work is at least the minimum
// expected based on elapsed time since the last checkpoint and
// maximum adjustment allowed by the retarget rules.
duration := blockHeader.Timestamp.Sub(checkpointTime)
requiredTarget := CompactToBig(b.calcEasiestDifficulty(
checkpointHeader.Bits, duration))
currentTarget := CompactToBig(blockHeader.Bits)
if currentTarget.Cmp(requiredTarget) > 0 {
str := fmt.Sprintf("block target difficulty of %064x "+
"is too low when compared to the previous "+
"checkpoint", currentTarget)
return false, ruleError(ErrDifficultyTooLow, str)
}
}
}
// Handle orphan blocks.
prevHash := &blockHeader.PrevBlock
if !prevHash.IsEqual(zeroHash) {
prevHashExists, err := b.blockExists(prevHash)
if err != nil {
return false, err
}
if !prevHashExists {
if !dryRun {
log.Infof("Adding orphan block %v with parent %v",
blockHash, prevHash)
b.addOrphanBlock(block)
}
return true, nil
}
}
// The block has passed all context independent checks and appears sane
// enough to potentially accept it into the block chain.
err = b.maybeAcceptBlock(block, flags)
if err != nil {
return false, err
}
// Don't process any orphans or log when the dry run flag is set.
if !dryRun {
// Accept any orphan blocks that depend on this block (they are
// no longer orphans) and repeat for those accepted blocks until
// there are no more.
err := b.processOrphans(blockHash, flags)
if err != nil {
return false, err
}
log.Debugf("Accepted block %v", blockHash)
}
return false, nil
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"compress/bzip2"
"encoding/binary"
"io"
"os"
"path/filepath"
"strings"
"testing"
"github.com/btcsuite/btcd/blockchain"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
// TestReorganization loads a set of test blocks which force a chain
// reorganization to test the block chain handling code.
// The test blocks were originally from a post on the bitcoin talk forums:
// https://bitcointalk.org/index.php?topic=46370.msg577556#msg577556
func TestReorganization(t *testing.T) {
// Intentionally load the side chain blocks out of order to ensure
// orphans are handled properly along with chain reorganization.
testFiles := []string{
"blk_0_to_4.dat.bz2",
"blk_4A.dat.bz2",
"blk_5A.dat.bz2",
"blk_3A.dat.bz2",
}
var blocks []*btcutil.Block
for _, file := range testFiles {
blockTmp, err := loadBlocks(file)
if err != nil {
t.Errorf("Error loading file: %v\n", err)
}
for _, block := range blockTmp {
blocks = append(blocks, block)
}
}
t.Logf("Number of blocks: %v\n", len(blocks))
// Create a new database and chain instance to run tests against.
chain, teardownFunc, err := chainSetup("reorg")
if err != nil {
t.Errorf("Failed to setup chain instance: %v", err)
return
}
defer teardownFunc()
// Since we're not dealing with the real block chain, disable
// checkpoints and set the coinbase maturity to 1.
chain.DisableCheckpoints(true)
blockchain.TstSetCoinbaseMaturity(1)
timeSource := blockchain.NewMedianTime()
expectedOrphans := map[int]struct{}{5: struct{}{}, 6: struct{}{}}
for i := 1; i < len(blocks); i++ {
isOrphan, err := chain.ProcessBlock(blocks[i], timeSource, blockchain.BFNone)
if err != nil {
t.Errorf("ProcessBlock fail on block %v: %v\n", i, err)
return
}
if _, ok := expectedOrphans[i]; !ok && isOrphan {
t.Errorf("ProcessBlock incorrectly returned block %v "+
"is an orphan\n", i)
}
}
return
}
// loadBlocks reads files containing bitcoin block data (gzipped but otherwise
// in the format bitcoind writes) from disk and returns them as an array of
// btcutil.Block. This is largely borrowed from the test code in btcdb.
func loadBlocks(filename string) (blocks []*btcutil.Block, err error) {
filename = filepath.Join("testdata/", filename)
var network = btcwire.MainNet
var dr io.Reader
var fi io.ReadCloser
fi, err = os.Open(filename)
if err != nil {
return
}
if strings.HasSuffix(filename, ".bz2") {
dr = bzip2.NewReader(fi)
} else {
dr = fi
}
defer fi.Close()
var block *btcutil.Block
err = nil
for height := int64(1); err == nil; height++ {
var rintbuf uint32
err = binary.Read(dr, binary.LittleEndian, &rintbuf)
if err == io.EOF {
// hit end of file at expected offset: no warning
height--
err = nil
break
}
if err != nil {
break
}
if rintbuf != uint32(network) {
break
}
err = binary.Read(dr, binary.LittleEndian, &rintbuf)
blocklen := rintbuf
rbytes := make([]byte, blocklen)
// read block
dr.Read(rbytes)
block, err = btcutil.NewBlockFromBytes(rbytes)
if err != nil {
return
}
blocks = append(blocks, block)
}
return
}

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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"fmt"
"math"
"runtime"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
// txValidateItem holds a transaction along with which input to validate.
type txValidateItem struct {
txInIndex int
txIn *btcwire.TxIn
tx *btcutil.Tx
}
// txValidator provides a type which asynchronously validates transaction
// inputs. It provides several channels for communication and a processing
// function that is intended to be in run multiple goroutines.
type txValidator struct {
validateChan chan *txValidateItem
quitChan chan struct{}
resultChan chan error
txStore TxStore
flags txscript.ScriptFlags
}
// sendResult sends the result of a script pair validation on the internal
// result channel while respecting the quit channel. The allows orderly
// shutdown when the validation process is aborted early due to a validation
// error in one of the other goroutines.
func (v *txValidator) sendResult(result error) {
select {
case v.resultChan <- result:
case <-v.quitChan:
}
}
// validateHandler consumes items to validate from the internal validate channel
// and returns the result of the validation on the internal result channel. It
// must be run as a goroutine.
func (v *txValidator) validateHandler() {
out:
for {
select {
case txVI := <-v.validateChan:
// Ensure the referenced input transaction is available.
txIn := txVI.txIn
originTxHash := &txIn.PreviousOutPoint.Hash
originTx, exists := v.txStore[*originTxHash]
if !exists || originTx.Err != nil || originTx.Tx == nil {
str := fmt.Sprintf("unable to find input "+
"transaction %v referenced from "+
"transaction %v", originTxHash,
txVI.tx.Sha())
err := ruleError(ErrMissingTx, str)
v.sendResult(err)
break out
}
originMsgTx := originTx.Tx.MsgTx()
// Ensure the output index in the referenced transaction
// is available.
originTxIndex := txIn.PreviousOutPoint.Index
if originTxIndex >= uint32(len(originMsgTx.TxOut)) {
str := fmt.Sprintf("out of bounds "+
"input index %d in transaction %v "+
"referenced from transaction %v",
originTxIndex, originTxHash,
txVI.tx.Sha())
err := ruleError(ErrBadTxInput, str)
v.sendResult(err)
break out
}
// Create a new script engine for the script pair.
sigScript := txIn.SignatureScript
pkScript := originMsgTx.TxOut[originTxIndex].PkScript
engine, err := txscript.NewScript(sigScript, pkScript,
txVI.txInIndex, txVI.tx.MsgTx(), v.flags)
if err != nil {
str := fmt.Sprintf("failed to parse input "+
"%s:%d which references output %s:%d - "+
"%v (input script bytes %x, prev output "+
"script bytes %x)", txVI.tx.Sha(),
txVI.txInIndex, originTxHash,
originTxIndex, err, sigScript, pkScript)
err := ruleError(ErrScriptMalformed, str)
v.sendResult(err)
break out
}
// Execute the script pair.
if err := engine.Execute(); err != nil {
str := fmt.Sprintf("failed to validate input "+
"%s:%d which references output %s:%d - "+
"%v (input script bytes %x, prev output "+
"script bytes %x)", txVI.tx.Sha(),
txVI.txInIndex, originTxHash,
originTxIndex, err, sigScript, pkScript)
err := ruleError(ErrScriptValidation, str)
v.sendResult(err)
break out
}
// Validation succeeded.
v.sendResult(nil)
case <-v.quitChan:
break out
}
}
}
// Validate validates the scripts for all of the passed transaction inputs using
// multiple goroutines.
func (v *txValidator) Validate(items []*txValidateItem) error {
if len(items) == 0 {
return nil
}
// Limit the number of goroutines to do script validation based on the
// number of processor cores. This help ensure the system stays
// reasonably responsive under heavy load.
maxGoRoutines := runtime.NumCPU() * 3
if maxGoRoutines <= 0 {
maxGoRoutines = 1
}
if maxGoRoutines > len(items) {
maxGoRoutines = len(items)
}
// Start up validation handlers that are used to asynchronously
// validate each transaction input.
for i := 0; i < maxGoRoutines; i++ {
go v.validateHandler()
}
// Validate each of the inputs. The quit channel is closed when any
// errors occur so all processing goroutines exit regardless of which
// input had the validation error.
numInputs := len(items)
currentItem := 0
processedItems := 0
for processedItems < numInputs {
// Only send items while there are still items that need to
// be processed. The select statement will never select a nil
// channel.
var validateChan chan *txValidateItem
var item *txValidateItem
if currentItem < numInputs {
validateChan = v.validateChan
item = items[currentItem]
}
select {
case validateChan <- item:
currentItem++
case err := <-v.resultChan:
processedItems++
if err != nil {
close(v.quitChan)
return err
}
}
}
close(v.quitChan)
return nil
}
// newTxValidator returns a new instance of txValidator to be used for
// validating transaction scripts asynchronously.
func newTxValidator(txStore TxStore, flags txscript.ScriptFlags) *txValidator {
return &txValidator{
validateChan: make(chan *txValidateItem),
quitChan: make(chan struct{}),
resultChan: make(chan error),
txStore: txStore,
flags: flags,
}
}
// ValidateTransactionScripts validates the scripts for the passed transaction
// using multiple goroutines.
func ValidateTransactionScripts(tx *btcutil.Tx, txStore TxStore, flags txscript.ScriptFlags) error {
// Collect all of the transaction inputs and required information for
// validation.
txIns := tx.MsgTx().TxIn
txValItems := make([]*txValidateItem, 0, len(txIns))
for txInIdx, txIn := range txIns {
// Skip coinbases.
if txIn.PreviousOutPoint.Index == math.MaxUint32 {
continue
}
txVI := &txValidateItem{
txInIndex: txInIdx,
txIn: txIn,
tx: tx,
}
txValItems = append(txValItems, txVI)
}
// Validate all of the inputs.
validator := newTxValidator(txStore, flags)
if err := validator.Validate(txValItems); err != nil {
return err
}
return nil
}
// checkBlockScripts executes and validates the scripts for all transactions in
// the passed block.
func checkBlockScripts(block *btcutil.Block, txStore TxStore) error {
// Setup the script validation flags. Blocks created after the BIP0016
// activation time need to have the pay-to-script-hash checks enabled.
var flags txscript.ScriptFlags
if block.MsgBlock().Header.Timestamp.After(txscript.Bip16Activation) {
flags |= txscript.ScriptBip16
}
// Collect all of the transaction inputs and required information for
// validation for all transactions in the block into a single slice.
numInputs := 0
for _, tx := range block.Transactions() {
numInputs += len(tx.MsgTx().TxIn)
}
txValItems := make([]*txValidateItem, 0, numInputs)
for _, tx := range block.Transactions() {
for txInIdx, txIn := range tx.MsgTx().TxIn {
// Skip coinbases.
if txIn.PreviousOutPoint.Index == math.MaxUint32 {
continue
}
txVI := &txValidateItem{
txInIndex: txInIdx,
txIn: txIn,
tx: tx,
}
txValItems = append(txValItems, txVI)
}
}
// Validate all of the inputs.
validator := newTxValidator(txStore, flags)
if err := validator.Validate(txValItems); err != nil {
return err
}
return nil
}

43
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// Copyright (c) 2013-2015 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"fmt"
"runtime"
"testing"
"github.com/btcsuite/btcd/blockchain"
)
// TestCheckBlockScripts ensures that validating the all of the scripts in a
// known-good block doesn't return an error.
func TestCheckBlockScripts(t *testing.T) {
runtime.GOMAXPROCS(runtime.NumCPU())
testBlockNum := 277647
blockDataFile := fmt.Sprintf("%d.dat.bz2", testBlockNum)
blocks, err := loadBlocks(blockDataFile)
if err != nil {
t.Errorf("Error loading file: %v\n", err)
return
}
if len(blocks) > 1 {
t.Errorf("The test block file must only have one block in it")
}
txStoreDataFile := fmt.Sprintf("%d.txstore.bz2", testBlockNum)
txStore, err := loadTxStore(txStoreDataFile)
if err != nil {
t.Errorf("Error loading txstore: %v\n", err)
return
}
if err := blockchain.TstCheckBlockScripts(blocks[0], txStore); err != nil {
t.Errorf("Transaction script validation failed: %v\n",
err)
return
}
}

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File path: reorgTest/blk_0_to_4.dat
Block 0:
f9beb4d9
1d010000
01000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 3ba3edfd 7a7b12b2 7ac72c3e 67768f61 7fc81bc3 888a5132 3a9fb8aa
4b1e5e4a 29ab5f49 ffff001d 1dac2b7c
01
01000000 01000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00ffffff ff4d04ff ff001d01 04455468 65205469 6d657320 30332f4a
616e2f32 30303920 4368616e 63656c6c 6f72206f 6e206272 696e6b20 6f662073
65636f6e 64206261 696c6f75 7420666f 72206261 6e6b73ff ffffff01 00f2052a
01000000 43410467 8afdb0fe 55482719 67f1a671 30b7105c d6a828e0 3909a679
62e0ea1f 61deb649 f6bc3f4c ef38c4f3 5504e51e c112de5c 384df7ba 0b8d578a
4c702b6b f11d5fac 00000000
Block 1:
f9beb4d9
d4000000
01000000 6fe28c0a b6f1b372 c1a6a246 ae63f74f 931e8365 e15a089c 68d61900
00000000 3bbd67ad e98fbbb7 0718cd80 f9e9acf9 3b5fae91 7bb2b41d 4c3bb82c
77725ca5 81ad5f49 ffff001d 44e69904
01
01000000 01000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00ffffff ff04722f 2e2bffff ffff0100 f2052a01 00000043 41046868
0737c76d abb801cb 2204f57d be4e4579 e4f710cd 67dc1b42 27592c81 e9b5cf02
b5ac9e8b 4c9f49be 5251056b 6a6d011e 4c37f6b6 d17ede6b 55faa235 19e2ac00
000000
Block 2:
f9beb4d9
95010000
01000000 13ca7940 4c11c63e ca906bbd f190b751 2872b857 1b5143ae e8cb5737
00000000 fc07c983 d7391736 0aeda657 29d0d4d3 2533eb84 76ee9d64 aa27538f
9b4fc00a d9af5f49 ffff001d 630bea22
02
01000000 01000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00ffffff ff04eb96 14e5ffff ffff0100 f2052a01 00000043 41046868
0737c76d abb801cb 2204f57d be4e4579 e4f710cd 67dc1b42 27592c81 e9b5cf02
b5ac9e8b 4c9f49be 5251056b 6a6d011e 4c37f6b6 d17ede6b 55faa235 19e2ac00
000000
01000000 0163451d 1002611c 1388d5ba 4ddfdf99 196a86b5 990fb5b0 dc786207
4fdcb8ee d2000000 004a4930 46022100 3dde52c6 5e339f45 7fe1015e 70eed208
872eb71e dd484c07 206b190e cb2ec3f8 02210011 c78dcfd0 3d43fa63 61242a33
6291ba2a 8c1ef5bc d5472126 2468f2bf 8dee4d01 ffffffff 0200ca9a 3b000000
001976a9 14cb2abd e8bccacc 32e893df 3a054b9e f7f227a4 ce88ac00 286bee00
00000019 76a914ee 26c56fc1 d942be8d 7a24b2a1 001dd894 69398088 ac000000
00
Block 3:
f9beb4d9
96020000
01000000 7d338254 0506faab 0d4cf179 45dda023 49db51f9 6233f24c 28002258
00000000 4806fe80 bf85931b 882ea645 77ca5a03 22bb8af2 3f277b20 55f160cd
972c8e8b 31b25f49 ffff001d e8f0c653
03
01000000 01000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00ffffff ff044abd 8159ffff ffff0100 f2052a01 00000043 4104b95c
249d84f4 17e3e395 a1274254 28b54067 1cc15881 eb828c17 b722a53f c599e21c
a5e56c90 f340988d 3933acc7 6beb832f d64cab07 8ddf3ce7 32923031 d1a8ac00
000000
01000000 01f287b5 e067e1cf 80f7da8a f89917b5 505094db d82412d9 35b665eb
bad253d3 77010000 008c4930 46022100 96ee0d02 b35fd61e 4960b44f f396f67e
01fe17f9 de4e0c17 b6a963bd ab2b50a6 02210034 920d4daa 7e9f8abe 5675c931
495809f9 0b9c1189 d05fbaf1 dd6696a5 b0d8f301 41046868 0737c76d abb801cb
2204f57d be4e4579 e4f710cd 67dc1b42 27592c81 e9b5cf02 b5ac9e8b 4c9f49be
5251056b 6a6d011e 4c37f6b6 d17ede6b 55faa235 19e2ffff ffff0100 286bee00
00000019 76a914c5 22664fb0 e55cdc5c 0cea73b4 aad97ec8 34323288 ac000000
00
01000000 01f287b5 e067e1cf 80f7da8a f89917b5 505094db d82412d9 35b665eb
bad253d3 77000000 008c4930 46022100 b08b922a c4bde411 1c229f92 9fe6eb6a
50161f98 1f4cf47e a9214d35 bf74d380 022100d2 f6640327 e677a1e1 cc474991
b9a48ba5 bd1e0c94 d1c8df49 f7b0193b 7ea4fa01 4104b95c 249d84f4 17e3e395
a1274254 28b54067 1cc15881 eb828c17 b722a53f c599e21c a5e56c90 f340988d
3933acc7 6beb832f d64cab07 8ddf3ce7 32923031 d1a8ffff ffff0100 ca9a3b00
00000019 76a914c5 22664fb0 e55cdc5c 0cea73b4 aad97ec8 34323288 ac000000
00
Block 4:
f9beb4d9
73010000
01000000 5da36499 06f35e09 9be42a1d 87b6dd42 11bc1400 6c220694 0807eaae
00000000 48eeeaed 2d9d8522 e6201173 743823fd 4b87cd8a ca8e6408 ec75ca38
302c2ff0 89b45f49 ffff001d 00530839
02
01000000 01000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00ffffff ff04d41d 2213ffff ffff0100 f2052a01 00000043 4104678a
fdb0fe55 48271967 f1a67130 b7105cd6 a828e039 09a67962 e0ea1f61 deb649f6
bc3f4cef 38c4f355 04e51ec1 12de5c38 4df7ba0b 8d578a4c 702b6bf1 1d5fac00
000000
01000000 0163451d 1002611c 1388d5ba 4ddfdf99 196a86b5 990fb5b0 dc786207
4fdcb8ee d2000000 004a4930 46022100 8c8fd57b 48762135 8d8f3e69 19f33e08
804736ff 83db47aa 248512e2 6df9b8ba 022100b0 c59e5ee7 bfcbfcd1 a4d83da9
55fb260e fda7f42a 25522625 a3d6f2d9 1174a701 ffffffff 0100f205 2a010000
001976a9 14c52266 4fb0e55c dc5c0cea 73b4aad9 7ec83432 3288ac00 000000
File path: reorgTest/blk_3A.dat
Block 3A:
f9beb4d9
96020000
01000000 7d338254 0506faab 0d4cf179 45dda023 49db51f9 6233f24c 28002258
00000000 5a15f573 1177a353 bdca7aab 20e16624 dfe90adc 70accadc 68016732
302c20a7 31b25f49 ffff001d 6a901440
03
01000000 01000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00ffffff ff04ad1b e7d5ffff ffff0100 f2052a01 00000043 4104ed83
704c95d8 29046f1a c2780621 1132102c 34e9ac7f fa1b7111 0658e5b9 d1bdedc4
16f5cefc 1db0625c d0c75de8 192d2b59 2d7e3b00 bcfb4a0e 860d880f d1fcac00
000000
01000000 01f287b5 e067e1cf 80f7da8a f89917b5 505094db d82412d9 35b665eb
bad253d3 77010000 008c4930 46022100 96ee0d02 b35fd61e 4960b44f f396f67e
01fe17f9 de4e0c17 b6a963bd ab2b50a6 02210034 920d4daa 7e9f8abe 5675c931
495809f9 0b9c1189 d05fbaf1 dd6696a5 b0d8f301 41046868 0737c76d abb801cb
2204f57d be4e4579 e4f710cd 67dc1b42 27592c81 e9b5cf02 b5ac9e8b 4c9f49be
5251056b 6a6d011e 4c37f6b6 d17ede6b 55faa235 19e2ffff ffff0100 286bee00
00000019 76a914c5 22664fb0 e55cdc5c 0cea73b4 aad97ec8 34323288 ac000000
00
01000000 01f287b5 e067e1cf 80f7da8a f89917b5 505094db d82412d9 35b665eb
bad253d3 77000000 008c4930 46022100 9cc67ddd aa6f592a 6b2babd4 d6ff954f
25a784cf 4fe4bb13 afb9f49b 08955119 022100a2 d99545b7 94080757 fcf2b563
f2e91287 86332f46 0ec6b90f f085fb28 41a69701 4104b95c 249d84f4 17e3e395
a1274254 28b54067 1cc15881 eb828c17 b722a53f c599e21c a5e56c90 f340988d
3933acc7 6beb832f d64cab07 8ddf3ce7 32923031 d1a8ffff ffff0100 ca9a3b00
00000019 76a914ee 26c56fc1 d942be8d 7a24b2a1 001dd894 69398088 ac000000
00
File path: reorgTest/blk_4A.dat
Block 4A:
f9beb4d9
d4000000
01000000 aae77468 2205667d 4f413a58 47cc8fe8 9795f1d5 645d5b24 1daf3c92
00000000 361c9cde a09637a0 d0c05c3b 4e7a5d91 9edb184a 0a4c7633 d92e2ddd
f04cb854 89b45f49 ffff001d 9e9aa1e8
01
01000000 01000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00ffffff ff0401b8 f3eaffff ffff0100 f2052a01 00000043 4104678a
fdb0fe55 48271967 f1a67130 b7105cd6 a828e039 09a67962 e0ea1f61 deb649f6
bc3f4cef 38c4f355 04e51ec1 12de5c38 4df7ba0b 8d578a4c 702b6bf1 1d5fac00
000000
File path: reorgTest/blk_5A.dat
Block 5A:
f9beb4d9
73010000
01000000 ebc7d0de 9c31a71b 7f41d275 2c080ba4 11e1854b d45cb2cf 8c1e4624
00000000 a607774b 79b8eb50 b52a5a32 c1754281 ec67f626 9561df28 57d1fe6a
ea82c696 e1b65f49 ffff001d 4a263577
02
01000000 01000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00ffffff ff049971 0c7dffff ffff0100 f2052a01 00000043 4104678a
fdb0fe55 48271967 f1a67130 b7105cd6 a828e039 09a67962 e0ea1f61 deb649f6
bc3f4cef 38c4f355 04e51ec1 12de5c38 4df7ba0b 8d578a4c 702b6bf1 1d5fac00
000000
01000000 0163451d 1002611c 1388d5ba 4ddfdf99 196a86b5 990fb5b0 dc786207
4fdcb8ee d2000000 004a4930 46022100 8c8fd57b 48762135 8d8f3e69 19f33e08
804736ff 83db47aa 248512e2 6df9b8ba 022100b0 c59e5ee7 bfcbfcd1 a4d83da9
55fb260e fda7f42a 25522625 a3d6f2d9 1174a701 ffffffff 0100f205 2a010000
001976a9 14c52266 4fb0e55c dc5c0cea 73b4aad9 7ec83432 3288ac00 000000

31
blockchain/timesorter.go Normal file
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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"time"
)
// timeSorter implements sort.Interface to allow a slice of timestamps to
// be sorted.
type timeSorter []time.Time
// Len returns the number of timestamps in the slice. It is part of the
// sort.Interface implementation.
func (s timeSorter) Len() int {
return len(s)
}
// Swap swaps the timestamps at the passed indices. It is part of the
// sort.Interface implementation.
func (s timeSorter) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
// Less returns whether the timstamp with index i should sort before the
// timestamp with index j. It is part of the sort.Interface implementation.
func (s timeSorter) Less(i, j int) bool {
return s[i].Before(s[j])
}

52
blockchain/timesorter_test.go Normal file
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// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"reflect"
"sort"
"testing"
"time"
"github.com/btcsuite/btcd/blockchain"
)
// TestTimeSorter tests the timeSorter implementation.
func TestTimeSorter(t *testing.T) {
tests := []struct {
in []time.Time
want []time.Time
}{
{
in: []time.Time{
time.Unix(1351228575, 0), // Fri Oct 26 05:16:15 UTC 2012 (Block #205000)
time.Unix(1351228575, 1), // Fri Oct 26 05:16:15 UTC 2012 (+1 nanosecond)
time.Unix(1348310759, 0), // Sat Sep 22 10:45:59 UTC 2012 (Block #200000)
time.Unix(1305758502, 0), // Wed May 18 22:41:42 UTC 2011 (Block #125000)
time.Unix(1347777156, 0), // Sun Sep 16 06:32:36 UTC 2012 (Block #199000)
time.Unix(1349492104, 0), // Sat Oct 6 02:55:04 UTC 2012 (Block #202000)
},
want: []time.Time{
time.Unix(1305758502, 0), // Wed May 18 22:41:42 UTC 2011 (Block #125000)
time.Unix(1347777156, 0), // Sun Sep 16 06:32:36 UTC 2012 (Block #199000)
time.Unix(1348310759, 0), // Sat Sep 22 10:45:59 UTC 2012 (Block #200000)
time.Unix(1349492104, 0), // Sat Oct 6 02:55:04 UTC 2012 (Block #202000)
time.Unix(1351228575, 0), // Fri Oct 26 05:16:15 UTC 2012 (Block #205000)
time.Unix(1351228575, 1), // Fri Oct 26 05:16:15 UTC 2012 (+1 nanosecond)
},
},
}
for i, test := range tests {
result := make([]time.Time, len(test.in))
copy(result, test.in)
sort.Sort(blockchain.TstTimeSorter(result))
if !reflect.DeepEqual(result, test.want) {
t.Errorf("timeSorter #%d got %v want %v", i, result,
test.want)
continue
}
}
}

318
blockchain/txlookup.go Normal file
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@ -0,0 +1,318 @@
// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"fmt"
"github.com/btcsuite/btcd/database"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
// TxData contains contextual information about transactions such as which block
// they were found in and whether or not the outputs are spent.
type TxData struct {
Tx *btcutil.Tx
Hash *btcwire.ShaHash
BlockHeight int64
Spent []bool
Err error
}
// TxStore is used to store transactions needed by other transactions for things
// such as script validation and double spend prevention. This also allows the
// transaction data to be treated as a view since it can contain the information
// from the point-of-view of different points in the chain.
type TxStore map[btcwire.ShaHash]*TxData
// connectTransactions updates the passed map by applying transaction and
// spend information for all the transactions in the passed block. Only
// transactions in the passed map are updated.
func connectTransactions(txStore TxStore, block *btcutil.Block) error {
// Loop through all of the transactions in the block to see if any of
// them are ones we need to update and spend based on the results map.
for _, tx := range block.Transactions() {
// Update the transaction store with the transaction information
// if it's one of the requested transactions.
msgTx := tx.MsgTx()
if txD, exists := txStore[*tx.Sha()]; exists {
txD.Tx = tx
txD.BlockHeight = block.Height()
txD.Spent = make([]bool, len(msgTx.TxOut))
txD.Err = nil
}
// Spend the origin transaction output.
for _, txIn := range msgTx.TxIn {
originHash := &txIn.PreviousOutPoint.Hash
originIndex := txIn.PreviousOutPoint.Index
if originTx, exists := txStore[*originHash]; exists {
if originIndex > uint32(len(originTx.Spent)) {
continue
}
originTx.Spent[originIndex] = true
}
}
}
return nil
}
// disconnectTransactions updates the passed map by undoing transaction and
// spend information for all transactions in the passed block. Only
// transactions in the passed map are updated.
func disconnectTransactions(txStore TxStore, block *btcutil.Block) error {
// Loop through all of the transactions in the block to see if any of
// them are ones that need to be undone based on the transaction store.
for _, tx := range block.Transactions() {
// Clear this transaction from the transaction store if needed.
// Only clear it rather than deleting it because the transaction
// connect code relies on its presence to decide whether or not
// to update the store and any transactions which exist on both
// sides of a fork would otherwise not be updated.
if txD, exists := txStore[*tx.Sha()]; exists {
txD.Tx = nil
txD.BlockHeight = 0
txD.Spent = nil
txD.Err = database.ErrTxShaMissing
}
// Unspend the origin transaction output.
for _, txIn := range tx.MsgTx().TxIn {
originHash := &txIn.PreviousOutPoint.Hash
originIndex := txIn.PreviousOutPoint.Index
originTx, exists := txStore[*originHash]
if exists && originTx.Tx != nil && originTx.Err == nil {
if originIndex > uint32(len(originTx.Spent)) {
continue
}
originTx.Spent[originIndex] = false
}
}
}
return nil
}
// fetchTxStoreMain fetches transaction data about the provided set of
// transactions from the point of view of the end of the main chain. It takes
// a flag which specifies whether or not fully spent transaction should be
// included in the results.
func fetchTxStoreMain(db database.Db, txSet map[btcwire.ShaHash]struct{}, includeSpent bool) TxStore {
// Just return an empty store now if there are no requested hashes.
txStore := make(TxStore)
if len(txSet) == 0 {
return txStore
}
// The transaction store map needs to have an entry for every requested
// transaction. By default, all the transactions are marked as missing.
// Each entry will be filled in with the appropriate data below.
txList := make([]*btcwire.ShaHash, 0, len(txSet))
for hash := range txSet {
hashCopy := hash
txStore[hash] = &TxData{Hash: &hashCopy, Err: database.ErrTxShaMissing}
txList = append(txList, &hashCopy)
}
// Ask the database (main chain) for the list of transactions. This
// will return the information from the point of view of the end of the
// main chain. Choose whether or not to include fully spent
// transactions depending on the passed flag.
fetchFunc := db.FetchUnSpentTxByShaList
if includeSpent {
fetchFunc = db.FetchTxByShaList
}
txReplyList := fetchFunc(txList)
for _, txReply := range txReplyList {
// Lookup the existing results entry to modify. Skip
// this reply if there is no corresponding entry in
// the transaction store map which really should not happen, but
// be safe.
txD, ok := txStore[*txReply.Sha]
if !ok {
continue
}
// Fill in the transaction details. A copy is used here since
// there is no guarantee the returned data isn't cached and
// this code modifies the data. A bug caused by modifying the
// cached data would likely be difficult to track down and could
// cause subtle errors, so avoid the potential altogether.
txD.Err = txReply.Err
if txReply.Err == nil {
txD.Tx = btcutil.NewTx(txReply.Tx)
txD.BlockHeight = txReply.Height
txD.Spent = make([]bool, len(txReply.TxSpent))
copy(txD.Spent, txReply.TxSpent)
}
}
return txStore
}
// fetchTxStore fetches transaction data about the provided set of transactions
// from the point of view of the given node. For example, a given node might
// be down a side chain where a transaction hasn't been spent from its point of
// view even though it might have been spent in the main chain (or another side
// chain). Another scenario is where a transaction exists from the point of
// view of the main chain, but doesn't exist in a side chain that branches
// before the block that contains the transaction on the main chain.
func (b *BlockChain) fetchTxStore(node *blockNode, txSet map[btcwire.ShaHash]struct{}) (TxStore, error) {
// Get the previous block node. This function is used over simply
// accessing node.parent directly as it will dynamically create previous
// block nodes as needed. This helps allow only the pieces of the chain
// that are needed to remain in memory.
prevNode, err := b.getPrevNodeFromNode(node)
if err != nil {
return nil, err
}
// If we haven't selected a best chain yet or we are extending the main
// (best) chain with a new block, fetch the requested set from the point
// of view of the end of the main (best) chain without including fully
// spent transactions in the results. This is a little more efficient
// since it means less transaction lookups are needed.
if b.bestChain == nil || (prevNode != nil && prevNode.hash.IsEqual(b.bestChain.hash)) {
txStore := fetchTxStoreMain(b.db, txSet, false)
return txStore, nil
}
// Fetch the requested set from the point of view of the end of the
// main (best) chain including fully spent transactions. The fully
// spent transactions are needed because the following code unspends
// them to get the correct point of view.
txStore := fetchTxStoreMain(b.db, txSet, true)
// The requested node is either on a side chain or is a node on the main
// chain before the end of it. In either case, we need to undo the
// transactions and spend information for the blocks which would be
// disconnected during a reorganize to the point of view of the
// node just before the requested node.
detachNodes, attachNodes := b.getReorganizeNodes(prevNode)
for e := detachNodes.Front(); e != nil; e = e.Next() {
n := e.Value.(*blockNode)
block, err := b.db.FetchBlockBySha(n.hash)
if err != nil {
return nil, err
}
disconnectTransactions(txStore, block)
}
// The transaction store is now accurate to either the node where the
// requested node forks off the main chain (in the case where the
// requested node is on a side chain), or the requested node itself if
// the requested node is an old node on the main chain. Entries in the
// attachNodes list indicate the requested node is on a side chain, so
// if there are no nodes to attach, we're done.
if attachNodes.Len() == 0 {
return txStore, nil
}
// The requested node is on a side chain, so we need to apply the
// transactions and spend information from each of the nodes to attach.
for e := attachNodes.Front(); e != nil; e = e.Next() {
n := e.Value.(*blockNode)
block, exists := b.blockCache[*n.hash]
if !exists {
return nil, fmt.Errorf("unable to find block %v in "+
"side chain cache for transaction search",
n.hash)
}
connectTransactions(txStore, block)
}
return txStore, nil
}
// fetchInputTransactions fetches the input transactions referenced by the
// transactions in the given block from its point of view. See fetchTxList
// for more details on what the point of view entails.
func (b *BlockChain) fetchInputTransactions(node *blockNode, block *btcutil.Block) (TxStore, error) {
// Build a map of in-flight transactions because some of the inputs in
// this block could be referencing other transactions earlier in this
// block which are not yet in the chain.
txInFlight := map[btcwire.ShaHash]int{}
transactions := block.Transactions()
for i, tx := range transactions {
txInFlight[*tx.Sha()] = i
}
// Loop through all of the transaction inputs (except for the coinbase
// which has no inputs) collecting them into sets of what is needed and
// what is already known (in-flight).
txNeededSet := make(map[btcwire.ShaHash]struct{})
txStore := make(TxStore)
for i, tx := range transactions[1:] {
for _, txIn := range tx.MsgTx().TxIn {
// Add an entry to the transaction store for the needed
// transaction with it set to missing by default.
originHash := &txIn.PreviousOutPoint.Hash
txD := &TxData{Hash: originHash, Err: database.ErrTxShaMissing}
txStore[*originHash] = txD
// It is acceptable for a transaction input to reference
// the output of another transaction in this block only
// if the referenced transaction comes before the
// current one in this block. Update the transaction
// store acccordingly when this is the case. Otherwise,
// we still need the transaction.
//
// NOTE: The >= is correct here because i is one less
// than the actual position of the transaction within
// the block due to skipping the coinbase.
if inFlightIndex, ok := txInFlight[*originHash]; ok &&
i >= inFlightIndex {
originTx := transactions[inFlightIndex]
txD.Tx = originTx
txD.BlockHeight = node.height
txD.Spent = make([]bool, len(originTx.MsgTx().TxOut))
txD.Err = nil
} else {
txNeededSet[*originHash] = struct{}{}
}
}
}
// Request the input transactions from the point of view of the node.
txNeededStore, err := b.fetchTxStore(node, txNeededSet)
if err != nil {
return nil, err
}
// Merge the results of the requested transactions and the in-flight
// transactions.
for _, txD := range txNeededStore {
txStore[*txD.Hash] = txD
}
return txStore, nil
}
// FetchTransactionStore fetches the input transactions referenced by the
// passed transaction from the point of view of the end of the main chain. It
// also attempts to fetch the transaction itself so the returned TxStore can be
// examined for duplicate transactions.
func (b *BlockChain) FetchTransactionStore(tx *btcutil.Tx) (TxStore, error) {
// Create a set of needed transactions from the transactions referenced
// by the inputs of the passed transaction. Also, add the passed
// transaction itself as a way for the caller to detect duplicates.
txNeededSet := make(map[btcwire.ShaHash]struct{})
txNeededSet[*tx.Sha()] = struct{}{}
for _, txIn := range tx.MsgTx().TxIn {
txNeededSet[txIn.PreviousOutPoint.Hash] = struct{}{}
}
// Request the input transactions from the point of view of the end of
// the main chain without including fully spent trasactions in the
// results. Fully spent transactions are only needed for chain
// reorganization which does not apply here.
txStore := fetchTxStoreMain(b.db, txNeededSet, false)
return txStore, nil
}

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@ -0,0 +1,951 @@
// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain
import (
"encoding/binary"
"fmt"
"math"
"math/big"
"time"
"github.com/btcsuite/btcd/database"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcnet"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
const (
// MaxSigOpsPerBlock is the maximum number of signature operations
// allowed for a block. It is a fraction of the max block payload size.
MaxSigOpsPerBlock = btcwire.MaxBlockPayload / 50
// lockTimeThreshold is the number below which a lock time is
// interpreted to be a block number. Since an average of one block
// is generated per 10 minutes, this allows blocks for about 9,512
// years. However, if the field is interpreted as a timestamp, given
// the lock time is a uint32, the max is sometime around 2106.
lockTimeThreshold uint32 = 5e8 // Tue Nov 5 00:53:20 1985 UTC
// MaxTimeOffsetSeconds is the maximum number of seconds a block time
// is allowed to be ahead of the current time. This is currently 2
// hours.
MaxTimeOffsetSeconds = 2 * 60 * 60
// MinCoinbaseScriptLen is the minimum length a coinbase script can be.
MinCoinbaseScriptLen = 2
// MaxCoinbaseScriptLen is the maximum length a coinbase script can be.
MaxCoinbaseScriptLen = 100
// medianTimeBlocks is the number of previous blocks which should be
// used to calculate the median time used to validate block timestamps.
medianTimeBlocks = 11
// serializedHeightVersion is the block version which changed block
// coinbases to start with the serialized block height.
serializedHeightVersion = 2
// baseSubsidy is the starting subsidy amount for mined blocks. This
// value is halved every SubsidyHalvingInterval blocks.
baseSubsidy = 50 * btcutil.SatoshiPerBitcoin
// CoinbaseMaturity is the number of blocks required before newly
// mined bitcoins (coinbase transactions) can be spent.
CoinbaseMaturity = 100
)
var (
// coinbaseMaturity is the internal variable used for validating the
// spending of coinbase outputs. A variable rather than the exported
// constant is used because the tests need the ability to modify it.
coinbaseMaturity = int64(CoinbaseMaturity)
// zeroHash is the zero value for a btcwire.ShaHash and is defined as
// a package level variable to avoid the need to create a new instance
// every time a check is needed.
zeroHash = &btcwire.ShaHash{}
// block91842Hash is one of the two nodes which violate the rules
// set forth in BIP0030. It is defined as a package level variable to
// avoid the need to create a new instance every time a check is needed.
block91842Hash = newShaHashFromStr("00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec")
// block91880Hash is one of the two nodes which violate the rules
// set forth in BIP0030. It is defined as a package level variable to
// avoid the need to create a new instance every time a check is needed.
block91880Hash = newShaHashFromStr("00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721")
)
// isNullOutpoint determines whether or not a previous transaction output point
// is set.
func isNullOutpoint(outpoint *btcwire.OutPoint) bool {
if outpoint.Index == math.MaxUint32 && outpoint.Hash.IsEqual(zeroHash) {
return true
}
return false
}
// IsCoinBase determines whether or not a transaction is a coinbase. A coinbase
// is a special transaction created by miners that has no inputs. This is
// represented in the block chain by a transaction with a single input that has
// a previous output transaction index set to the maximum value along with a
// zero hash.
func IsCoinBase(tx *btcutil.Tx) bool {
msgTx := tx.MsgTx()
// A coin base must only have one transaction input.
if len(msgTx.TxIn) != 1 {
return false
}
// The previous output of a coin base must have a max value index and
// a zero hash.
prevOut := msgTx.TxIn[0].PreviousOutPoint
if prevOut.Index != math.MaxUint32 || !prevOut.Hash.IsEqual(zeroHash) {
return false
}
return true
}
// IsFinalizedTransaction determines whether or not a transaction is finalized.
func IsFinalizedTransaction(tx *btcutil.Tx, blockHeight int64, blockTime time.Time) bool {
msgTx := tx.MsgTx()
// Lock time of zero means the transaction is finalized.
lockTime := msgTx.LockTime
if lockTime == 0 {
return true
}
// The lock time field of a transaction is either a block height at
// which the transaction is finalized or a timestamp depending on if the
// value is before the lockTimeThreshold. When it is under the
// threshold it is a block height.
blockTimeOrHeight := int64(0)
if lockTime < lockTimeThreshold {
blockTimeOrHeight = blockHeight
} else {
blockTimeOrHeight = blockTime.Unix()
}
if int64(lockTime) < blockTimeOrHeight {
return true
}
// At this point, the transaction's lock time hasn't occured yet, but
// the transaction might still be finalized if the sequence number
// for all transaction inputs is maxed out.
for _, txIn := range msgTx.TxIn {
if txIn.Sequence != math.MaxUint32 {
return false
}
}
return true
}
// isBIP0030Node returns whether or not the passed node represents one of the
// two blocks that violate the BIP0030 rule which prevents transactions from
// overwriting old ones.
func isBIP0030Node(node *blockNode) bool {
if node.height == 91842 && node.hash.IsEqual(block91842Hash) {
return true
}
if node.height == 91880 && node.hash.IsEqual(block91880Hash) {
return true
}
return false
}
// CalcBlockSubsidy returns the subsidy amount a block at the provided height
// should have. This is mainly used for determining how much the coinbase for
// newly generated blocks awards as well as validating the coinbase for blocks
// has the expected value.
//
// The subsidy is halved every SubsidyHalvingInterval blocks. Mathematically
// this is: baseSubsidy / 2^(height/subsidyHalvingInterval)
//
// At the target block generation rate for the main network, this is
// approximately every 4 years.
func CalcBlockSubsidy(height int64, netParams *btcnet.Params) int64 {
if netParams.SubsidyHalvingInterval == 0 {
return baseSubsidy
}
// Equivalent to: baseSubsidy / 2^(height/subsidyHalvingInterval)
return baseSubsidy >> uint(height/int64(netParams.SubsidyHalvingInterval))
}
// CheckTransactionSanity performs some preliminary checks on a transaction to
// ensure it is sane. These checks are context free.
func CheckTransactionSanity(tx *btcutil.Tx) error {
// A transaction must have at least one input.
msgTx := tx.MsgTx()
if len(msgTx.TxIn) == 0 {
return ruleError(ErrNoTxInputs, "transaction has no inputs")
}
// A transaction must have at least one output.
if len(msgTx.TxOut) == 0 {
return ruleError(ErrNoTxOutputs, "transaction has no outputs")
}
// A transaction must not exceed the maximum allowed block payload when
// serialized.
serializedTxSize := tx.MsgTx().SerializeSize()
if serializedTxSize > btcwire.MaxBlockPayload {
str := fmt.Sprintf("serialized transaction is too big - got "+
"%d, max %d", serializedTxSize, btcwire.MaxBlockPayload)
return ruleError(ErrTxTooBig, str)
}
// Ensure the transaction amounts are in range. Each transaction
// output must not be negative or more than the max allowed per
// transaction. Also, the total of all outputs must abide by the same
// restrictions. All amounts in a transaction are in a unit value known
// as a satoshi. One bitcoin is a quantity of satoshi as defined by the
// SatoshiPerBitcoin constant.
var totalSatoshi int64
for _, txOut := range msgTx.TxOut {
satoshi := txOut.Value
if satoshi < 0 {
str := fmt.Sprintf("transaction output has negative "+
"value of %v", satoshi)
return ruleError(ErrBadTxOutValue, str)
}
if satoshi > btcutil.MaxSatoshi {
str := fmt.Sprintf("transaction output value of %v is "+
"higher than max allowed value of %v", satoshi,
btcutil.MaxSatoshi)
return ruleError(ErrBadTxOutValue, str)
}
// TODO(davec): No need to check < 0 here as satoshi is
// guaranteed to be positive per the above check. Also need
// to add overflow checks.
totalSatoshi += satoshi
if totalSatoshi < 0 {
str := fmt.Sprintf("total value of all transaction "+
"outputs has negative value of %v", totalSatoshi)
return ruleError(ErrBadTxOutValue, str)
}
if totalSatoshi > btcutil.MaxSatoshi {
str := fmt.Sprintf("total value of all transaction "+
"outputs is %v which is higher than max "+
"allowed value of %v", totalSatoshi,
btcutil.MaxSatoshi)
return ruleError(ErrBadTxOutValue, str)
}
}
// Check for duplicate transaction inputs.
existingTxOut := make(map[btcwire.OutPoint]struct{})
for _, txIn := range msgTx.TxIn {
if _, exists := existingTxOut[txIn.PreviousOutPoint]; exists {
return ruleError(ErrDuplicateTxInputs, "transaction "+
"contains duplicate inputs")
}
existingTxOut[txIn.PreviousOutPoint] = struct{}{}
}
// Coinbase script length must be between min and max length.
if IsCoinBase(tx) {
slen := len(msgTx.TxIn[0].SignatureScript)
if slen < MinCoinbaseScriptLen || slen > MaxCoinbaseScriptLen {
str := fmt.Sprintf("coinbase transaction script length "+
"of %d is out of range (min: %d, max: %d)",
slen, MinCoinbaseScriptLen, MaxCoinbaseScriptLen)
return ruleError(ErrBadCoinbaseScriptLen, str)
}
} else {
// Previous transaction outputs referenced by the inputs to this
// transaction must not be null.
for _, txIn := range msgTx.TxIn {
prevOut := &txIn.PreviousOutPoint
if isNullOutpoint(prevOut) {
return ruleError(ErrBadTxInput, "transaction "+
"input refers to previous output that "+
"is null")
}
}
}
return nil
}
// checkProofOfWork ensures the block header bits which indicate the target
// difficulty is in min/max range and that the block hash is less than the
// target difficulty as claimed.
//
//
// The flags modify the behavior of this function as follows:
// - BFNoPoWCheck: The check to ensure the block hash is less than the target
// difficulty is not performed.
func checkProofOfWork(block *btcutil.Block, powLimit *big.Int, flags BehaviorFlags) error {
// The target difficulty must be larger than zero.
target := CompactToBig(block.MsgBlock().Header.Bits)
if target.Sign() <= 0 {
str := fmt.Sprintf("block target difficulty of %064x is too low",
target)
return ruleError(ErrUnexpectedDifficulty, str)
}
// The target difficulty must be less than the maximum allowed.
if target.Cmp(powLimit) > 0 {
str := fmt.Sprintf("block target difficulty of %064x is "+
"higher than max of %064x", target, powLimit)
return ruleError(ErrUnexpectedDifficulty, str)
}
// The block hash must be less than the claimed target unless the flag
// to avoid proof of work checks is set.
if flags&BFNoPoWCheck != BFNoPoWCheck {
// The block hash must be less than the claimed target.
blockHash, err := block.Sha()
if err != nil {
return err
}
hashNum := ShaHashToBig(blockHash)
if hashNum.Cmp(target) > 0 {
str := fmt.Sprintf("block hash of %064x is higher than "+
"expected max of %064x", hashNum, target)
return ruleError(ErrHighHash, str)
}
}
return nil
}
// CheckProofOfWork ensures the block header bits which indicate the target
// difficulty is in min/max range and that the block hash is less than the
// target difficulty as claimed.
func CheckProofOfWork(block *btcutil.Block, powLimit *big.Int) error {
return checkProofOfWork(block, powLimit, BFNone)
}
// CountSigOps returns the number of signature operations for all transaction
// input and output scripts in the provided transaction. This uses the
// quicker, but imprecise, signature operation counting mechanism from
// txscript.
func CountSigOps(tx *btcutil.Tx) int {
msgTx := tx.MsgTx()
// Accumulate the number of signature operations in all transaction
// inputs.
totalSigOps := 0
for _, txIn := range msgTx.TxIn {
numSigOps := txscript.GetSigOpCount(txIn.SignatureScript)
totalSigOps += numSigOps
}
// Accumulate the number of signature operations in all transaction
// outputs.
for _, txOut := range msgTx.TxOut {
numSigOps := txscript.GetSigOpCount(txOut.PkScript)
totalSigOps += numSigOps
}
return totalSigOps
}
// CountP2SHSigOps returns the number of signature operations for all input
// transactions which are of the pay-to-script-hash type. This uses the
// precise, signature operation counting mechanism from the script engine which
// requires access to the input transaction scripts.
func CountP2SHSigOps(tx *btcutil.Tx, isCoinBaseTx bool, txStore TxStore) (int, error) {
// Coinbase transactions have no interesting inputs.
if isCoinBaseTx {
return 0, nil
}
// Accumulate the number of signature operations in all transaction
// inputs.
msgTx := tx.MsgTx()
totalSigOps := 0
for _, txIn := range msgTx.TxIn {
// Ensure the referenced input transaction is available.
txInHash := &txIn.PreviousOutPoint.Hash
originTx, exists := txStore[*txInHash]
if !exists || originTx.Err != nil || originTx.Tx == nil {
str := fmt.Sprintf("unable to find input transaction "+
"%v referenced from transaction %v", txInHash,
tx.Sha())
return 0, ruleError(ErrMissingTx, str)
}
originMsgTx := originTx.Tx.MsgTx()
// Ensure the output index in the referenced transaction is
// available.
originTxIndex := txIn.PreviousOutPoint.Index
if originTxIndex >= uint32(len(originMsgTx.TxOut)) {
str := fmt.Sprintf("out of bounds input index %d in "+
"transaction %v referenced from transaction %v",
originTxIndex, txInHash, tx.Sha())
return 0, ruleError(ErrBadTxInput, str)
}
// We're only interested in pay-to-script-hash types, so skip
// this input if it's not one.
pkScript := originMsgTx.TxOut[originTxIndex].PkScript
if !txscript.IsPayToScriptHash(pkScript) {
continue
}
// Count the precise number of signature operations in the
// referenced public key script.
sigScript := txIn.SignatureScript
numSigOps := txscript.GetPreciseSigOpCount(sigScript, pkScript,
true)
// We could potentially overflow the accumulator so check for
// overflow.
lastSigOps := totalSigOps
totalSigOps += numSigOps
if totalSigOps < lastSigOps {
str := fmt.Sprintf("the public key script from "+
"output index %d in transaction %v contains "+
"too many signature operations - overflow",
originTxIndex, txInHash)
return 0, ruleError(ErrTooManySigOps, str)
}
}
return totalSigOps, nil
}
// checkBlockSanity performs some preliminary checks on a block to ensure it is
// sane before continuing with block processing. These checks are context free.
//
// The flags do not modify the behavior of this function directly, however they
// are needed to pass along to checkProofOfWork.
func checkBlockSanity(block *btcutil.Block, powLimit *big.Int, timeSource MedianTimeSource, flags BehaviorFlags) error {
// A block must have at least one transaction.
msgBlock := block.MsgBlock()
numTx := len(msgBlock.Transactions)
if numTx == 0 {
return ruleError(ErrNoTransactions, "block does not contain "+
"any transactions")
}
// A block must not have more transactions than the max block payload.
if numTx > btcwire.MaxBlockPayload {
str := fmt.Sprintf("block contains too many transactions - "+
"got %d, max %d", numTx, btcwire.MaxBlockPayload)
return ruleError(ErrTooManyTransactions, str)
}
// A block must not exceed the maximum allowed block payload when
// serialized.
serializedSize := msgBlock.SerializeSize()
if serializedSize > btcwire.MaxBlockPayload {
str := fmt.Sprintf("serialized block is too big - got %d, "+
"max %d", serializedSize, btcwire.MaxBlockPayload)
return ruleError(ErrBlockTooBig, str)
}
// Ensure the proof of work bits in the block header is in min/max range
// and the block hash is less than the target value described by the
// bits.
err := checkProofOfWork(block, powLimit, flags)
if err != nil {
return err
}
// A block timestamp must not have a greater precision than one second.
// This check is necessary because Go time.Time values support
// nanosecond precision whereas the consensus rules only apply to
// seconds and it's much nicer to deal with standard Go time values
// instead of converting to seconds everywhere.
header := &block.MsgBlock().Header
if !header.Timestamp.Equal(time.Unix(header.Timestamp.Unix(), 0)) {
str := fmt.Sprintf("block timestamp of %v has a higher "+
"precision than one second", header.Timestamp)
return ruleError(ErrInvalidTime, str)
}
// Ensure the block time is not too far in the future.
maxTimestamp := timeSource.AdjustedTime().Add(time.Second *
MaxTimeOffsetSeconds)
if header.Timestamp.After(maxTimestamp) {
str := fmt.Sprintf("block timestamp of %v is too far in the "+
"future", header.Timestamp)
return ruleError(ErrTimeTooNew, str)
}
// The first transaction in a block must be a coinbase.
transactions := block.Transactions()
if !IsCoinBase(transactions[0]) {
return ruleError(ErrFirstTxNotCoinbase, "first transaction in "+
"block is not a coinbase")
}
// A block must not have more than one coinbase.
for i, tx := range transactions[1:] {
if IsCoinBase(tx) {
str := fmt.Sprintf("block contains second coinbase at "+
"index %d", i)
return ruleError(ErrMultipleCoinbases, str)
}
}
// Do some preliminary checks on each transaction to ensure they are
// sane before continuing.
for _, tx := range transactions {
err := CheckTransactionSanity(tx)
if err != nil {
return err
}
}
// Build merkle tree and ensure the calculated merkle root matches the
// entry in the block header. This also has the effect of caching all
// of the transaction hashes in the block to speed up future hash
// checks. Bitcoind builds the tree here and checks the merkle root
// after the following checks, but there is no reason not to check the
// merkle root matches here.
merkles := BuildMerkleTreeStore(block.Transactions())
calculatedMerkleRoot := merkles[len(merkles)-1]
if !header.MerkleRoot.IsEqual(calculatedMerkleRoot) {
str := fmt.Sprintf("block merkle root is invalid - block "+
"header indicates %v, but calculated value is %v",
header.MerkleRoot, calculatedMerkleRoot)
return ruleError(ErrBadMerkleRoot, str)
}
// Check for duplicate transactions. This check will be fairly quick
// since the transaction hashes are already cached due to building the
// merkle tree above.
existingTxHashes := make(map[btcwire.ShaHash]struct{})
for _, tx := range transactions {
hash := tx.Sha()
if _, exists := existingTxHashes[*hash]; exists {
str := fmt.Sprintf("block contains duplicate "+
"transaction %v", hash)
return ruleError(ErrDuplicateTx, str)
}
existingTxHashes[*hash] = struct{}{}
}
// The number of signature operations must be less than the maximum
// allowed per block.
totalSigOps := 0
for _, tx := range transactions {
// We could potentially overflow the accumulator so check for
// overflow.
lastSigOps := totalSigOps
totalSigOps += CountSigOps(tx)
if totalSigOps < lastSigOps || totalSigOps > MaxSigOpsPerBlock {
str := fmt.Sprintf("block contains too many signature "+
"operations - got %v, max %v", totalSigOps,
MaxSigOpsPerBlock)
return ruleError(ErrTooManySigOps, str)
}
}
return nil
}
// CheckBlockSanity performs some preliminary checks on a block to ensure it is
// sane before continuing with block processing. These checks are context free.
func CheckBlockSanity(block *btcutil.Block, powLimit *big.Int, timeSource MedianTimeSource) error {
return checkBlockSanity(block, powLimit, timeSource, BFNone)
}
// checkSerializedHeight checks if the signature script in the passed
// transaction starts with the serialized block height of wantHeight.
func checkSerializedHeight(coinbaseTx *btcutil.Tx, wantHeight int64) error {
sigScript := coinbaseTx.MsgTx().TxIn[0].SignatureScript
if len(sigScript) < 1 {
str := "the coinbase signature script for blocks of " +
"version %d or greater must start with the " +
"length of the serialized block height"
str = fmt.Sprintf(str, serializedHeightVersion)
return ruleError(ErrMissingCoinbaseHeight, str)
}
serializedLen := int(sigScript[0])
if len(sigScript[1:]) < serializedLen {
str := "the coinbase signature script for blocks of " +
"version %d or greater must start with the " +
"serialized block height"
str = fmt.Sprintf(str, serializedLen)
return ruleError(ErrMissingCoinbaseHeight, str)
}
serializedHeightBytes := make([]byte, 8, 8)
copy(serializedHeightBytes, sigScript[1:serializedLen+1])
serializedHeight := binary.LittleEndian.Uint64(serializedHeightBytes)
if int64(serializedHeight) != wantHeight {
str := fmt.Sprintf("the coinbase signature script serialized "+
"block height is %d when %d was expected",
serializedHeight, wantHeight)
return ruleError(ErrBadCoinbaseHeight, str)
}
return nil
}
// isTransactionSpent returns whether or not the provided transaction data
// describes a fully spent transaction. A fully spent transaction is one where
// all outputs have been spent.
func isTransactionSpent(txD *TxData) bool {
for _, isOutputSpent := range txD.Spent {
if !isOutputSpent {
return false
}
}
return true
}
// checkBIP0030 ensures blocks do not contain duplicate transactions which
// 'overwrite' older transactions that are not fully spent. This prevents an
// attack where a coinbase and all of its dependent transactions could be
// duplicated to effectively revert the overwritten transactions to a single
// confirmation thereby making them vulnerable to a double spend.
//
// For more details, see https://en.bitcoin.it/wiki/BIP_0030 and
// http://r6.ca/blog/20120206T005236Z.html.
func (b *BlockChain) checkBIP0030(node *blockNode, block *btcutil.Block) error {
// Attempt to fetch duplicate transactions for all of the transactions
// in this block from the point of view of the parent node.
fetchSet := make(map[btcwire.ShaHash]struct{})
for _, tx := range block.Transactions() {
fetchSet[*tx.Sha()] = struct{}{}
}
txResults, err := b.fetchTxStore(node, fetchSet)
if err != nil {
return err
}
// Examine the resulting data about the requested transactions.
for _, txD := range txResults {
switch txD.Err {
// A duplicate transaction was not found. This is the most
// common case.
case database.ErrTxShaMissing:
continue
// A duplicate transaction was found. This is only allowed if
// the duplicate transaction is fully spent.
case nil:
if !isTransactionSpent(txD) {
str := fmt.Sprintf("tried to overwrite "+
"transaction %v at block height %d "+
"that is not fully spent", txD.Hash,
txD.BlockHeight)
return ruleError(ErrOverwriteTx, str)
}
// Some other unexpected error occurred. Return it now.
default:
return txD.Err
}
}
return nil
}
// CheckTransactionInputs performs a series of checks on the inputs to a
// transaction to ensure they are valid. An example of some of the checks
// include verifying all inputs exist, ensuring the coinbase seasoning
// requirements are met, detecting double spends, validating all values and fees
// are in the legal range and the total output amount doesn't exceed the input
// amount, and verifying the signatures to prove the spender was the owner of
// the bitcoins and therefore allowed to spend them. As it checks the inputs,
// it also calculates the total fees for the transaction and returns that value.
func CheckTransactionInputs(tx *btcutil.Tx, txHeight int64, txStore TxStore) (int64, error) {
// Coinbase transactions have no inputs.
if IsCoinBase(tx) {
return 0, nil
}
txHash := tx.Sha()
var totalSatoshiIn int64
for _, txIn := range tx.MsgTx().TxIn {
// Ensure the input is available.
txInHash := &txIn.PreviousOutPoint.Hash
originTx, exists := txStore[*txInHash]
if !exists || originTx.Err != nil || originTx.Tx == nil {
str := fmt.Sprintf("unable to find input transaction "+
"%v for transaction %v", txInHash, txHash)
return 0, ruleError(ErrMissingTx, str)
}
// Ensure the transaction is not spending coins which have not
// yet reached the required coinbase maturity.
if IsCoinBase(originTx.Tx) {
originHeight := originTx.BlockHeight
blocksSincePrev := txHeight - originHeight
if blocksSincePrev < coinbaseMaturity {
str := fmt.Sprintf("tried to spend coinbase "+
"transaction %v from height %v at "+
"height %v before required maturity "+
"of %v blocks", txInHash, originHeight,
txHeight, coinbaseMaturity)
return 0, ruleError(ErrImmatureSpend, str)
}
}
// Ensure the transaction is not double spending coins.
originTxIndex := txIn.PreviousOutPoint.Index
if originTxIndex >= uint32(len(originTx.Spent)) {
str := fmt.Sprintf("out of bounds input index %d in "+
"transaction %v referenced from transaction %v",
originTxIndex, txInHash, txHash)
return 0, ruleError(ErrBadTxInput, str)
}
if originTx.Spent[originTxIndex] {
str := fmt.Sprintf("transaction %v tried to double "+
"spend output %v", txHash, txIn.PreviousOutPoint)
return 0, ruleError(ErrDoubleSpend, str)
}
// Ensure the transaction amounts are in range. Each of the
// output values of the input transactions must not be negative
// or more than the max allowed per transaction. All amounts in
// a transaction are in a unit value known as a satoshi. One
// bitcoin is a quantity of satoshi as defined by the
// SatoshiPerBitcoin constant.
originTxSatoshi := originTx.Tx.MsgTx().TxOut[originTxIndex].Value
if originTxSatoshi < 0 {
str := fmt.Sprintf("transaction output has negative "+
"value of %v", originTxSatoshi)
return 0, ruleError(ErrBadTxOutValue, str)
}
if originTxSatoshi > btcutil.MaxSatoshi {
str := fmt.Sprintf("transaction output value of %v is "+
"higher than max allowed value of %v",
originTxSatoshi, btcutil.MaxSatoshi)
return 0, ruleError(ErrBadTxOutValue, str)
}
// The total of all outputs must not be more than the max
// allowed per transaction. Also, we could potentially overflow
// the accumulator so check for overflow.
lastSatoshiIn := totalSatoshiIn
totalSatoshiIn += originTxSatoshi
if totalSatoshiIn < lastSatoshiIn ||
totalSatoshiIn > btcutil.MaxSatoshi {
str := fmt.Sprintf("total value of all transaction "+
"inputs is %v which is higher than max "+
"allowed value of %v", totalSatoshiIn,
btcutil.MaxSatoshi)
return 0, ruleError(ErrBadTxOutValue, str)
}
// Mark the referenced output as spent.
originTx.Spent[originTxIndex] = true
}
// Calculate the total output amount for this transaction. It is safe
// to ignore overflow and out of range errors here because those error
// conditions would have already been caught by checkTransactionSanity.
var totalSatoshiOut int64
for _, txOut := range tx.MsgTx().TxOut {
totalSatoshiOut += txOut.Value
}
// Ensure the transaction does not spend more than its inputs.
if totalSatoshiIn < totalSatoshiOut {
str := fmt.Sprintf("total value of all transaction inputs for "+
"transaction %v is %v which is less than the amount "+
"spent of %v", txHash, totalSatoshiIn, totalSatoshiOut)
return 0, ruleError(ErrSpendTooHigh, str)
}
// NOTE: bitcoind checks if the transaction fees are < 0 here, but that
// is an impossible condition because of the check above that ensures
// the inputs are >= the outputs.
txFeeInSatoshi := totalSatoshiIn - totalSatoshiOut
return txFeeInSatoshi, nil
}
// checkConnectBlock performs several checks to confirm connecting the passed
// block to the main chain (including whatever reorganization might be necessary
// to get this node to the main chain) does not violate any rules.
//
// The CheckConnectBlock function makes use of this function to perform the
// bulk of its work. The only difference is this function accepts a node which
// may or may not require reorganization to connect it to the main chain whereas
// CheckConnectBlock creates a new node which specifically connects to the end
// of the current main chain and then calls this function with that node.
//
// See the comments for CheckConnectBlock for some examples of the type of
// checks performed by this function.
func (b *BlockChain) checkConnectBlock(node *blockNode, block *btcutil.Block) error {
// If the side chain blocks end up in the database, a call to
// CheckBlockSanity should be done here in case a previous version
// allowed a block that is no longer valid. However, since the
// implementation only currently uses memory for the side chain blocks,
// it isn't currently necessary.
// The coinbase for the Genesis block is not spendable, so just return
// now.
if node.hash.IsEqual(b.netParams.GenesisHash) && b.bestChain == nil {
return nil
}
// BIP0030 added a rule to prevent blocks which contain duplicate
// transactions that 'overwrite' older transactions which are not fully
// spent. See the documentation for checkBIP0030 for more details.
//
// There are two blocks in the chain which violate this
// rule, so the check must be skipped for those blocks. The
// isBIP0030Node function is used to determine if this block is one
// of the two blocks that must be skipped.
enforceBIP0030 := !isBIP0030Node(node)
if enforceBIP0030 {
err := b.checkBIP0030(node, block)
if err != nil {
return err
}
}
// Request a map that contains all input transactions for the block from
// the point of view of its position within the block chain. These
// transactions are needed for verification of things such as
// transaction inputs, counting pay-to-script-hashes, and scripts.
txInputStore, err := b.fetchInputTransactions(node, block)
if err != nil {
return err
}
// BIP0016 describes a pay-to-script-hash type that is considered a
// "standard" type. The rules for this BIP only apply to transactions
// after the timestamp defined by txscript.Bip16Activation. See
// https://en.bitcoin.it/wiki/BIP_0016 for more details.
enforceBIP0016 := false
if node.timestamp.After(txscript.Bip16Activation) {
enforceBIP0016 = true
}
// The number of signature operations must be less than the maximum
// allowed per block. Note that the preliminary sanity checks on a
// block also include a check similar to this one, but this check
// expands the count to include a precise count of pay-to-script-hash
// signature operations in each of the input transaction public key
// scripts.
transactions := block.Transactions()
totalSigOps := 0
for i, tx := range transactions {
numsigOps := CountSigOps(tx)
if enforceBIP0016 {
// Since the first (and only the first) transaction has
// already been verified to be a coinbase transaction,
// use i == 0 as an optimization for the flag to
// countP2SHSigOps for whether or not the transaction is
// a coinbase transaction rather than having to do a
// full coinbase check again.
numP2SHSigOps, err := CountP2SHSigOps(tx, i == 0,
txInputStore)
if err != nil {
return err
}
numsigOps += numP2SHSigOps
}
// Check for overflow or going over the limits. We have to do
// this on every loop iteration to avoid overflow.
lastSigops := totalSigOps
totalSigOps += numsigOps
if totalSigOps < lastSigops || totalSigOps > MaxSigOpsPerBlock {
str := fmt.Sprintf("block contains too many "+
"signature operations - got %v, max %v",
totalSigOps, MaxSigOpsPerBlock)
return ruleError(ErrTooManySigOps, str)
}
}
// Perform several checks on the inputs for each transaction. Also
// accumulate the total fees. This could technically be combined with
// the loop above instead of running another loop over the transactions,
// but by separating it we can avoid running the more expensive (though
// still relatively cheap as compared to running the scripts) checks
// against all the inputs when the signature operations are out of
// bounds.
var totalFees int64
for _, tx := range transactions {
txFee, err := CheckTransactionInputs(tx, node.height, txInputStore)
if err != nil {
return err
}
// Sum the total fees and ensure we don't overflow the
// accumulator.
lastTotalFees := totalFees
totalFees += txFee
if totalFees < lastTotalFees {
return ruleError(ErrBadFees, "total fees for block "+
"overflows accumulator")
}
}
// The total output values of the coinbase transaction must not exceed
// the expected subsidy value plus total transaction fees gained from
// mining the block. It is safe to ignore overflow and out of range
// errors here because those error conditions would have already been
// caught by checkTransactionSanity.
var totalSatoshiOut int64
for _, txOut := range transactions[0].MsgTx().TxOut {
totalSatoshiOut += txOut.Value
}
expectedSatoshiOut := CalcBlockSubsidy(node.height, b.netParams) +
totalFees
if totalSatoshiOut > expectedSatoshiOut {
str := fmt.Sprintf("coinbase transaction for block pays %v "+
"which is more than expected value of %v",
totalSatoshiOut, expectedSatoshiOut)
return ruleError(ErrBadCoinbaseValue, str)
}
// Don't run scripts if this node is before the latest known good
// checkpoint since the validity is verified via the checkpoints (all
// transactions are included in the merkle root hash and any changes
// will therefore be detected by the next checkpoint). This is a huge
// optimization because running the scripts is the most time consuming
// portion of block handling.
checkpoint := b.LatestCheckpoint()
runScripts := !b.noVerify
if checkpoint != nil && node.height <= checkpoint.Height {
runScripts = false
}
// Now that the inexpensive checks are done and have passed, verify the
// transactions are actually allowed to spend the coins by running the
// expensive ECDSA signature check scripts. Doing this last helps
// prevent CPU exhaustion attacks.
if runScripts {
err := checkBlockScripts(block, txInputStore)
if err != nil {
return err
}
}
return nil
}
// CheckConnectBlock performs several checks to confirm connecting the passed
// block to the main chain does not violate any rules. An example of some of
// the checks performed are ensuring connecting the block would not cause any
// duplicate transaction hashes for old transactions that aren't already fully
// spent, double spends, exceeding the maximum allowed signature operations
// per block, invalid values in relation to the expected block subsidy, or fail
// transaction script validation.
//
// This function is NOT safe for concurrent access.
func (b *BlockChain) CheckConnectBlock(block *btcutil.Block) error {
prevNode := b.bestChain
blockSha, _ := block.Sha()
newNode := newBlockNode(&block.MsgBlock().Header, blockSha, block.Height())
if prevNode != nil {
newNode.parent = prevNode
newNode.workSum.Add(prevNode.workSum, newNode.workSum)
}
return b.checkConnectBlock(newNode, block)
}

381
blockchain/validate_test.go Normal file
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@ -0,0 +1,381 @@
// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package blockchain_test
import (
"math"
"reflect"
"testing"
"time"
"github.com/btcsuite/btcd/blockchain"
"github.com/btcsuite/btcnet"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwire"
)
// TestCheckConnectBlock tests the CheckConnectBlock function to ensure it
// fails
func TestCheckConnectBlock(t *testing.T) {
// Create a new database and chain instance to run tests against.
chain, teardownFunc, err := chainSetup("checkconnectblock")
if err != nil {
t.Errorf("Failed to setup chain instance: %v", err)
return
}
defer teardownFunc()
err = chain.GenerateInitialIndex()
if err != nil {
t.Errorf("GenerateInitialIndex: %v", err)
}
// The genesis block should fail to connect since it's already
// inserted.
genesisBlock := btcnet.MainNetParams.GenesisBlock
err = chain.CheckConnectBlock(btcutil.NewBlock(genesisBlock))
if err == nil {
t.Errorf("CheckConnectBlock: Did not received expected error")
}
}
// TestCheckBlockSanity tests the CheckBlockSanity function to ensure it works
// as expected.
func TestCheckBlockSanity(t *testing.T) {
powLimit := btcnet.MainNetParams.PowLimit
block := btcutil.NewBlock(&Block100000)
timeSource := blockchain.NewMedianTime()
err := blockchain.CheckBlockSanity(block, powLimit, timeSource)
if err != nil {
t.Errorf("CheckBlockSanity: %v", err)
}
// Ensure a block that has a timestamp with a precision higher than one
// second fails.
timestamp := block.MsgBlock().Header.Timestamp
block.MsgBlock().Header.Timestamp = timestamp.Add(time.Nanosecond)
err = blockchain.CheckBlockSanity(block, powLimit, timeSource)
if err == nil {
t.Errorf("CheckBlockSanity: error is nil when it shouldn't be")
}
}
// TestCheckSerializedHeight tests the checkSerializedHeight function with
// various serialized heights and also does negative tests to ensure errors
// and handled properly.
func TestCheckSerializedHeight(t *testing.T) {
// Create an empty coinbase template to be used in the tests below.
coinbaseOutpoint := btcwire.NewOutPoint(&btcwire.ShaHash{}, math.MaxUint32)
coinbaseTx := btcwire.NewMsgTx()
coinbaseTx.Version = 2
coinbaseTx.AddTxIn(btcwire.NewTxIn(coinbaseOutpoint, nil))
// Expected rule errors.
missingHeightError := blockchain.RuleError{
ErrorCode: blockchain.ErrMissingCoinbaseHeight,
}
badHeightError := blockchain.RuleError{
ErrorCode: blockchain.ErrBadCoinbaseHeight,
}
tests := []struct {
sigScript []byte // Serialized data
wantHeight int64 // Expected height
err error // Expected error type
}{
// No serialized height length.
{[]byte{}, 0, missingHeightError},
// Serialized height length with no height bytes.
{[]byte{0x02}, 0, missingHeightError},
// Serialized height length with too few height bytes.
{[]byte{0x02, 0x4a}, 0, missingHeightError},
// Serialized height that needs 2 bytes to encode.
{[]byte{0x02, 0x4a, 0x52}, 21066, nil},
// Serialized height that needs 2 bytes to encode, but backwards
// endianness.
{[]byte{0x02, 0x4a, 0x52}, 19026, badHeightError},
// Serialized height that needs 3 bytes to encode.
{[]byte{0x03, 0x40, 0x0d, 0x03}, 200000, nil},
// Serialized height that needs 3 bytes to encode, but backwards
// endianness.
{[]byte{0x03, 0x40, 0x0d, 0x03}, 1074594560, badHeightError},
}
t.Logf("Running %d tests", len(tests))
for i, test := range tests {
msgTx := coinbaseTx.Copy()
msgTx.TxIn[0].SignatureScript = test.sigScript
tx := btcutil.NewTx(msgTx)
err := blockchain.TstCheckSerializedHeight(tx, test.wantHeight)
if reflect.TypeOf(err) != reflect.TypeOf(test.err) {
t.Errorf("checkSerializedHeight #%d wrong error type "+
"got: %v <%T>, want: %T", i, err, err, test.err)
continue
}
if rerr, ok := err.(blockchain.RuleError); ok {
trerr := test.err.(blockchain.RuleError)
if rerr.ErrorCode != trerr.ErrorCode {
t.Errorf("checkSerializedHeight #%d wrong "+
"error code got: %v, want: %v", i,
rerr.ErrorCode, trerr.ErrorCode)
continue
}
}
}
}
// Block100000 defines block 100,000 of the block chain. It is used to
// test Block operations.
var Block100000 = btcwire.MsgBlock{
Header: btcwire.BlockHeader{
Version: 1,
PrevBlock: btcwire.ShaHash([32]byte{ // Make go vet happy.
0x50, 0x12, 0x01, 0x19, 0x17, 0x2a, 0x61, 0x04,
0x21, 0xa6, 0xc3, 0x01, 0x1d, 0xd3, 0x30, 0xd9,
0xdf, 0x07, 0xb6, 0x36, 0x16, 0xc2, 0xcc, 0x1f,
0x1c, 0xd0, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00,
}), // 000000000002d01c1fccc21636b607dfd930d31d01c3a62104612a1719011250
MerkleRoot: btcwire.ShaHash([32]byte{ // Make go vet happy.
0x66, 0x57, 0xa9, 0x25, 0x2a, 0xac, 0xd5, 0xc0,
0xb2, 0x94, 0x09, 0x96, 0xec, 0xff, 0x95, 0x22,
0x28, 0xc3, 0x06, 0x7c, 0xc3, 0x8d, 0x48, 0x85,
0xef, 0xb5, 0xa4, 0xac, 0x42, 0x47, 0xe9, 0xf3,
}), // f3e94742aca4b5ef85488dc37c06c3282295ffec960994b2c0d5ac2a25a95766
Timestamp: time.Unix(1293623863, 0), // 2010-12-29 11:57:43 +0000 UTC
Bits: 0x1b04864c, // 453281356
Nonce: 0x10572b0f, // 274148111
},
Transactions: []*btcwire.MsgTx{
{
Version: 1,
TxIn: []*btcwire.TxIn{
{
PreviousOutPoint: btcwire.OutPoint{
Hash: btcwire.ShaHash{},
Index: 0xffffffff,
},
SignatureScript: []byte{
0x04, 0x4c, 0x86, 0x04, 0x1b, 0x02, 0x06, 0x02,
},
Sequence: 0xffffffff,
},
},
TxOut: []*btcwire.TxOut{
{
Value: 0x12a05f200, // 5000000000
PkScript: []byte{
0x41, // OP_DATA_65
0x04, 0x1b, 0x0e, 0x8c, 0x25, 0x67, 0xc1, 0x25,
0x36, 0xaa, 0x13, 0x35, 0x7b, 0x79, 0xa0, 0x73,
0xdc, 0x44, 0x44, 0xac, 0xb8, 0x3c, 0x4e, 0xc7,
0xa0, 0xe2, 0xf9, 0x9d, 0xd7, 0x45, 0x75, 0x16,
0xc5, 0x81, 0x72, 0x42, 0xda, 0x79, 0x69, 0x24,
0xca, 0x4e, 0x99, 0x94, 0x7d, 0x08, 0x7f, 0xed,
0xf9, 0xce, 0x46, 0x7c, 0xb9, 0xf7, 0xc6, 0x28,
0x70, 0x78, 0xf8, 0x01, 0xdf, 0x27, 0x6f, 0xdf,
0x84, // 65-byte signature
0xac, // OP_CHECKSIG
},
},
},
LockTime: 0,
},
{
Version: 1,
TxIn: []*btcwire.TxIn{
{
PreviousOutPoint: btcwire.OutPoint{
Hash: btcwire.ShaHash([32]byte{ // Make go vet happy.
0x03, 0x2e, 0x38, 0xe9, 0xc0, 0xa8, 0x4c, 0x60,
0x46, 0xd6, 0x87, 0xd1, 0x05, 0x56, 0xdc, 0xac,
0xc4, 0x1d, 0x27, 0x5e, 0xc5, 0x5f, 0xc0, 0x07,
0x79, 0xac, 0x88, 0xfd, 0xf3, 0x57, 0xa1, 0x87,
}), // 87a157f3fd88ac7907c05fc55e271dc4acdc5605d187d646604ca8c0e9382e03
Index: 0,
},
SignatureScript: []byte{
0x49, // OP_DATA_73
0x30, 0x46, 0x02, 0x21, 0x00, 0xc3, 0x52, 0xd3,
0xdd, 0x99, 0x3a, 0x98, 0x1b, 0xeb, 0xa4, 0xa6,
0x3a, 0xd1, 0x5c, 0x20, 0x92, 0x75, 0xca, 0x94,
0x70, 0xab, 0xfc, 0xd5, 0x7d, 0xa9, 0x3b, 0x58,
0xe4, 0xeb, 0x5d, 0xce, 0x82, 0x02, 0x21, 0x00,
0x84, 0x07, 0x92, 0xbc, 0x1f, 0x45, 0x60, 0x62,
0x81, 0x9f, 0x15, 0xd3, 0x3e, 0xe7, 0x05, 0x5c,
0xf7, 0xb5, 0xee, 0x1a, 0xf1, 0xeb, 0xcc, 0x60,
0x28, 0xd9, 0xcd, 0xb1, 0xc3, 0xaf, 0x77, 0x48,
0x01, // 73-byte signature
0x41, // OP_DATA_65
0x04, 0xf4, 0x6d, 0xb5, 0xe9, 0xd6, 0x1a, 0x9d,
0xc2, 0x7b, 0x8d, 0x64, 0xad, 0x23, 0xe7, 0x38,
0x3a, 0x4e, 0x6c, 0xa1, 0x64, 0x59, 0x3c, 0x25,
0x27, 0xc0, 0x38, 0xc0, 0x85, 0x7e, 0xb6, 0x7e,
0xe8, 0xe8, 0x25, 0xdc, 0xa6, 0x50, 0x46, 0xb8,
0x2c, 0x93, 0x31, 0x58, 0x6c, 0x82, 0xe0, 0xfd,
0x1f, 0x63, 0x3f, 0x25, 0xf8, 0x7c, 0x16, 0x1b,
0xc6, 0xf8, 0xa6, 0x30, 0x12, 0x1d, 0xf2, 0xb3,
0xd3, // 65-byte pubkey
},
Sequence: 0xffffffff,
},
},
TxOut: []*btcwire.TxOut{
{
Value: 0x2123e300, // 556000000
PkScript: []byte{
0x76, // OP_DUP
0xa9, // OP_HASH160
0x14, // OP_DATA_20
0xc3, 0x98, 0xef, 0xa9, 0xc3, 0x92, 0xba, 0x60,
0x13, 0xc5, 0xe0, 0x4e, 0xe7, 0x29, 0x75, 0x5e,
0xf7, 0xf5, 0x8b, 0x32,
0x88, // OP_EQUALVERIFY
0xac, // OP_CHECKSIG
},
},
{
Value: 0x108e20f00, // 4444000000
PkScript: []byte{
0x76, // OP_DUP
0xa9, // OP_HASH160
0x14, // OP_DATA_20
0x94, 0x8c, 0x76, 0x5a, 0x69, 0x14, 0xd4, 0x3f,
0x2a, 0x7a, 0xc1, 0x77, 0xda, 0x2c, 0x2f, 0x6b,
0x52, 0xde, 0x3d, 0x7c,
0x88, // OP_EQUALVERIFY
0xac, // OP_CHECKSIG
},
},
},
LockTime: 0,
},
{
Version: 1,
TxIn: []*btcwire.TxIn{
{
PreviousOutPoint: btcwire.OutPoint{
Hash: btcwire.ShaHash([32]byte{ // Make go vet happy.
0xc3, 0x3e, 0xbf, 0xf2, 0xa7, 0x09, 0xf1, 0x3d,
0x9f, 0x9a, 0x75, 0x69, 0xab, 0x16, 0xa3, 0x27,
0x86, 0xaf, 0x7d, 0x7e, 0x2d, 0xe0, 0x92, 0x65,
0xe4, 0x1c, 0x61, 0xd0, 0x78, 0x29, 0x4e, 0xcf,
}), // cf4e2978d0611ce46592e02d7e7daf8627a316ab69759a9f3df109a7f2bf3ec3
Index: 1,
},
SignatureScript: []byte{
0x47, // OP_DATA_71
0x30, 0x44, 0x02, 0x20, 0x03, 0x2d, 0x30, 0xdf,
0x5e, 0xe6, 0xf5, 0x7f, 0xa4, 0x6c, 0xdd, 0xb5,
0xeb, 0x8d, 0x0d, 0x9f, 0xe8, 0xde, 0x6b, 0x34,
0x2d, 0x27, 0x94, 0x2a, 0xe9, 0x0a, 0x32, 0x31,
0xe0, 0xba, 0x33, 0x3e, 0x02, 0x20, 0x3d, 0xee,
0xe8, 0x06, 0x0f, 0xdc, 0x70, 0x23, 0x0a, 0x7f,
0x5b, 0x4a, 0xd7, 0xd7, 0xbc, 0x3e, 0x62, 0x8c,
0xbe, 0x21, 0x9a, 0x88, 0x6b, 0x84, 0x26, 0x9e,
0xae, 0xb8, 0x1e, 0x26, 0xb4, 0xfe, 0x01,
0x41, // OP_DATA_65
0x04, 0xae, 0x31, 0xc3, 0x1b, 0xf9, 0x12, 0x78,
0xd9, 0x9b, 0x83, 0x77, 0xa3, 0x5b, 0xbc, 0xe5,
0xb2, 0x7d, 0x9f, 0xff, 0x15, 0x45, 0x68, 0x39,
0xe9, 0x19, 0x45, 0x3f, 0xc7, 0xb3, 0xf7, 0x21,
0xf0, 0xba, 0x40, 0x3f, 0xf9, 0x6c, 0x9d, 0xee,
0xb6, 0x80, 0xe5, 0xfd, 0x34, 0x1c, 0x0f, 0xc3,
0xa7, 0xb9, 0x0d, 0xa4, 0x63, 0x1e, 0xe3, 0x95,
0x60, 0x63, 0x9d, 0xb4, 0x62, 0xe9, 0xcb, 0x85,
0x0f, // 65-byte pubkey
},
Sequence: 0xffffffff,
},
},
TxOut: []*btcwire.TxOut{
{
Value: 0xf4240, // 1000000
PkScript: []byte{
0x76, // OP_DUP
0xa9, // OP_HASH160
0x14, // OP_DATA_20
0xb0, 0xdc, 0xbf, 0x97, 0xea, 0xbf, 0x44, 0x04,
0xe3, 0x1d, 0x95, 0x24, 0x77, 0xce, 0x82, 0x2d,
0xad, 0xbe, 0x7e, 0x10,
0x88, // OP_EQUALVERIFY
0xac, // OP_CHECKSIG
},
},
{
Value: 0x11d260c0, // 299000000
PkScript: []byte{
0x76, // OP_DUP
0xa9, // OP_HASH160
0x14, // OP_DATA_20
0x6b, 0x12, 0x81, 0xee, 0xc2, 0x5a, 0xb4, 0xe1,
0xe0, 0x79, 0x3f, 0xf4, 0xe0, 0x8a, 0xb1, 0xab,
0xb3, 0x40, 0x9c, 0xd9,
0x88, // OP_EQUALVERIFY
0xac, // OP_CHECKSIG
},
},
},
LockTime: 0,
},
{
Version: 1,
TxIn: []*btcwire.TxIn{
{
PreviousOutPoint: btcwire.OutPoint{
Hash: btcwire.ShaHash([32]byte{ // Make go vet happy.
0x0b, 0x60, 0x72, 0xb3, 0x86, 0xd4, 0xa7, 0x73,
0x23, 0x52, 0x37, 0xf6, 0x4c, 0x11, 0x26, 0xac,
0x3b, 0x24, 0x0c, 0x84, 0xb9, 0x17, 0xa3, 0x90,
0x9b, 0xa1, 0xc4, 0x3d, 0xed, 0x5f, 0x51, 0xf4,
}), // f4515fed3dc4a19b90a317b9840c243bac26114cf637522373a7d486b372600b
Index: 0,
},
SignatureScript: []byte{
0x49, // OP_DATA_73
0x30, 0x46, 0x02, 0x21, 0x00, 0xbb, 0x1a, 0xd2,
0x6d, 0xf9, 0x30, 0xa5, 0x1c, 0xce, 0x11, 0x0c,
0xf4, 0x4f, 0x7a, 0x48, 0xc3, 0xc5, 0x61, 0xfd,
0x97, 0x75, 0x00, 0xb1, 0xae, 0x5d, 0x6b, 0x6f,
0xd1, 0x3d, 0x0b, 0x3f, 0x4a, 0x02, 0x21, 0x00,
0xc5, 0xb4, 0x29, 0x51, 0xac, 0xed, 0xff, 0x14,
0xab, 0xba, 0x27, 0x36, 0xfd, 0x57, 0x4b, 0xdb,
0x46, 0x5f, 0x3e, 0x6f, 0x8d, 0xa1, 0x2e, 0x2c,
0x53, 0x03, 0x95, 0x4a, 0xca, 0x7f, 0x78, 0xf3,
0x01, // 73-byte signature
0x41, // OP_DATA_65
0x04, 0xa7, 0x13, 0x5b, 0xfe, 0x82, 0x4c, 0x97,
0xec, 0xc0, 0x1e, 0xc7, 0xd7, 0xe3, 0x36, 0x18,
0x5c, 0x81, 0xe2, 0xaa, 0x2c, 0x41, 0xab, 0x17,
0x54, 0x07, 0xc0, 0x94, 0x84, 0xce, 0x96, 0x94,
0xb4, 0x49, 0x53, 0xfc, 0xb7, 0x51, 0x20, 0x65,
0x64, 0xa9, 0xc2, 0x4d, 0xd0, 0x94, 0xd4, 0x2f,
0xdb, 0xfd, 0xd5, 0xaa, 0xd3, 0xe0, 0x63, 0xce,
0x6a, 0xf4, 0xcf, 0xaa, 0xea, 0x4e, 0xa1, 0x4f,
0xbb, // 65-byte pubkey
},
Sequence: 0xffffffff,
},
},
TxOut: []*btcwire.TxOut{
{
Value: 0xf4240, // 1000000
PkScript: []byte{
0x76, // OP_DUP
0xa9, // OP_HASH160
0x14, // OP_DATA_20
0x39, 0xaa, 0x3d, 0x56, 0x9e, 0x06, 0xa1, 0xd7,
0x92, 0x6d, 0xc4, 0xbe, 0x11, 0x93, 0xc9, 0x9b,
0xf2, 0xeb, 0x9e, 0xe0,
0x88, // OP_EQUALVERIFY
0xac, // OP_CHECKSIG
},
},
},
LockTime: 0,
},
},
}