lbcd/blockchain
Dave Collins 59169540c3
blockchain: Reconstruct headers from block nodes.
This modifies the block node structure to include a couple of extra
fields needed to be able to reconstruct the block header from a node,
and exposes a new function from chain to fetch the block headers which
takes advantage of the new functionality to reconstruct the headers from
memory when possible.  Finally, it updates both the p2p and RPC servers
to make use of the new function.

This is useful since many of the block header fields need to be kept in
order to form the block index anyways and storing the extra fields means
the database does not have to be consulted when headers are requested if
the associated node is still in memory.

The following timings show representative performance gains as measured
from one system:

new: Time to fetch 100000 headers:   59ms
old: Time to fetch 100000 headers: 4783ms
2017-02-01 12:27:56 -06:00
..
fullblocktests blockchain: Remove isMajorityVersion code. 2016-11-30 14:26:13 -06:00
indexers multi: Simplify code per gosimple linter. 2016-11-03 13:00:35 -05:00
testdata blockchain: Rework to use new db interface. 2016-04-11 16:47:27 -05:00
accept.go blockchain: Store side chain blocks in database. 2017-01-31 10:25:43 -06:00
bench_test.go Relicense to the btcsuite developers. 2015-05-01 12:00:56 -05:00
blocklocator.go Correct typo 2017-01-11 13:21:14 -08:00
chain.go blockchain: Reconstruct headers from block nodes. 2017-02-01 12:27:56 -06:00
chain_test.go multi: Improvements to configurable checkpoints. 2017-01-23 12:07:54 -06:00
chainio.go blockchain: Use int64 timestamps in block nodes. 2017-01-31 17:51:29 -06:00
chainio_test.go chainhash: Abstract hash logic to new package. (#729) 2016-08-08 14:04:33 -05:00
checkpoints.go multi: Improvements to configurable checkpoints. 2017-01-23 12:07:54 -06:00
common_test.go blockchain: Allow adding additional checkpoints 2017-01-18 23:56:43 +01:00
compress.go blockchain: Rework to use new db interface. 2016-04-11 16:47:27 -05:00
compress_test.go blockchain: Rework to use new db interface. 2016-04-11 16:47:27 -05:00
difficulty.go blockchain: Use int64 timestamps in block nodes. 2017-01-31 17:51:29 -06:00
difficulty_test.go Relicense to the btcsuite developers. 2015-05-01 12:00:56 -05:00
doc.go Relicense to the btcsuite developers. 2015-05-01 12:00:56 -05:00
error.go Implement infrastructure for BIP0009. 2016-11-30 13:51:59 -06:00
error_test.go Implement infrastructure for BIP0009. 2016-11-30 13:51:59 -06:00
example_test.go blockchain: Expose main chain flag on ProcessBlock. 2016-10-13 16:47:50 -05:00
fullblocks_test.go blockchain: Add block validation infrastructure. 2016-10-17 12:16:53 -05:00
internal_test.go blockchain: Use int64 timestamps in block nodes. 2017-01-31 17:51:29 -06:00
log.go multi: Remove unused code found by deadcode. 2016-11-02 17:37:31 -05:00
mediantime.go Relicense to the btcsuite developers. 2015-05-01 12:00:56 -05:00
mediantime_test.go Relicense to the btcsuite developers. 2015-05-01 12:00:56 -05:00
merkle.go chainhash: Abstract hash logic to new package. (#729) 2016-08-08 14:04:33 -05:00
merkle_test.go Relicense to the btcsuite developers. 2015-05-01 12:00:56 -05:00
notifications.go blockchain: Rework to use new db interface. 2016-04-11 16:47:27 -05:00
process.go blockchain: Expose main chain flag on ProcessBlock. 2016-10-13 16:47:50 -05:00
README.md docs: Make various README.md files consistent. 2015-10-23 14:51:36 -05:00
reorganization_test.go multi: Improvements to configurable checkpoints. 2017-01-23 12:07:54 -06:00
scriptval.go multi: Simplify code per gosimple linter. 2016-11-03 13:00:35 -05:00
scriptval_test.go blockchain: make scriptval_test fail more nicely 2016-09-16 15:44:27 -04:00
thresholdstate.go blockchain: Correct startup threshold state warns. 2016-12-03 13:42:26 -06:00
thresholdstate_test.go Implement infrastructure for BIP0009. 2016-11-30 13:51:59 -06:00
timesorter.go blockchain: Use int64 timestamps in block nodes. 2017-01-31 17:51:29 -06:00
timesorter_test.go blockchain: Use int64 timestamps in block nodes. 2017-01-31 17:51:29 -06:00
utxoviewpoint.go mempool: Add basic test harness infrastructure. 2016-08-24 10:04:40 -05:00
validate.go blockchain: Use int64 timestamps in block nodes. 2017-01-31 17:51:29 -06:00
validate_test.go wire: Make NewMsgTx accept the tx version. 2016-10-27 14:09:29 -05:00
versionbits.go blockchain: Correct startup threshold state warns. 2016-12-03 13:42:26 -06:00

blockchain

[Build Status] (https://travis-ci.org/btcsuite/btcd) ![ISC License] (http://img.shields.io/badge/license-ISC-blue.svg) [GoDoc] (http://godoc.org/github.com/btcsuite/btcd/blockchain)

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.

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.

Installation and Updating

$ go get -u 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

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 the btcsuite developers. 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:

    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:

    git tag -v TAG_NAME
    

License

Package blockchain is licensed under the copyfree ISC License.